FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Tsuda, T VanZandtz, TE Saito, H AF Tsuda, T VanZandtz, TE Saito, H TI Zenith-angle dependence of VHF specular reflection echoes in the lower atmosphere SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID GRAVITY-WAVE SPECTRUM; PHASED-ARRAY SYSTEM; ASPECT SENSITIVITY; LOWER STRATOSPHERE; MU-RADAR; TROPOSPHERE; TEMPERATURE; POWER; SCATTERING; FLUCTUATIONS AB We studied the characteristics of specular echoes reflected from stratified layers in the troposphere and lower stratosphere. In particular, we observed echoes at antenna-beam zenith angles, theta, from 0 degrees to 28 degrees in steps of 2 degrees. When the radar measurements were averaged over about 30 min, the zenith angle dependence of the echo power normalized by the vertical power, (S) over tilde(theta), was generally the same for sufficiently intense reflection echoes. That is, the echo power was largest in the vertical direction, decreased to about -10 dB at 6 degrees, and then gradually decreased to a constant level between -15 and -25 dB at theta greater than or equal to 20 degrees. This constant level is interpreted as the isotropic turbulence scattering level <(S)over tilde(i)>. The width of (S) over tilde(theta) was significantly broader than expected for specular reflection from a perfectly horizontal layer. In order to explain this broadening, we developed two numerical models that describe statistically the slope of a reflection layer that has been distorted by vertical gravity-wave motions. With realistic gravity-wave spectra, the shape of (S) over tilde(theta) for theta = 0-6 degrees was successfully explained. However, from 8 degrees to 18 degrees the observed (S) over tilde(theta) was enhanced by as much as 7 dB over the model. From the observations we showed that all of the reflection echoes, including the enhanced echoes at theta = 8-18 degrees, are probably due to the same process. Then we showed that the discrepancy with the model may be the result of our neglect of the horizontal component of gravity-wave motions, which was done in order to constrain the number of calculations. (C) 1997 Elsevier Science Ltd. C1 NOAA,AERON LAB,BOULDER,CO 80303. RP Tsuda, T (reprint author), KYOTO UNIV,CTR RADIO ATMOSPHER SCI,UJI,KYOTO,JAPAN. RI tsuda, toshitaka/A-3035-2015 NR 35 TC 37 Z9 37 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAY PY 1997 VL 59 IS 7 BP 761 EP 775 DI 10.1016/S1364-6826(96)00057-0 PG 15 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA WP044 UT WOS:A1997WP04400003 ER PT J AU Defibaugh, DR CarrilloNava, E Hurly, JJ Moldover, MR Schmidt, JW Weber, LA AF Defibaugh, DR CarrilloNava, E Hurly, JJ Moldover, MR Schmidt, JW Weber, LA TI Thermodynamic properties of HFC-338mccq, CF3CF2CF2CH2F,1,1,1,2,2,3,3,4-octafluorobutane SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID VAPOR-PRESSURE; EBULLIOMETRIC MEASUREMENT; SURFACE-TENSION; LIQUID; DIFLUOROMETHANE; TEMPERATURE; DENSITIES; EQUATION; STATE; R141B AB We report the thermodynamic properties of 1,1,1,2,2,3,3,4-octafluorobutane, which has been designated as HFC-338 mccq by the refrigeration industry. The measurements span the temperature and pressure ranges encountered in thermal machinery. The properties measured include the vapor pressure, the density of the compressed liquid, the refractive index of both the saturated liquid and the saturated vapor, the critical temperature, the capillary rise, and the speed of sound in the vapor phase. These data were used to determine the ideal gas heat capacity, the saturated liquid and vapor densities, the surface tension, the virial equation of state for the vapor phase, and estimates of the critical pressure and density. A Carnahan-Starling-DeSantis equation of state was deduced from the measured fluid properties. RP Defibaugh, DR (reprint author), NIST,PHYS & CHEM PROPERTIES DIV,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. RI Moldover, Michael/E-6384-2013 NR 17 TC 21 Z9 21 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAY-JUN PY 1997 VL 42 IS 3 BP 488 EP 496 DI 10.1021/je9603133 PG 9 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA WY825 UT WOS:A1997WY82500013 ER PT J AU Overland, JE Adams, JM Bond, NA AF Overland, JE Adams, JM Bond, NA TI Regional variation of winter temperatures in the Arctic SO JOURNAL OF CLIMATE LA English DT Article ID NORTHERN-HEMISPHERE; PATTERNS; DATASET; VORTEX; WAVES AB The surface temperature field in the Arctic winter is primarily controlled by downward longwave radiation, which is determined by local atmospheric; temperature and humidity profiles and the presence of clouds. The authors show that regional differences in the atmospheric thermal energy budget are related to the tropospheric circulation in the Arctic. Data sources include several gridded meteorological datasets and surface and rawinsonde observational data. Four independent climatologies of mean January surface temperature show consistent spatial patterns: coldest temperatures in the western Arctic north of Canada and warmer regions in the Chukchi, Greenland, and Barents Seas. Data from the five winters of 1986-90 illustrate the coupling between the surface temperature, the downward longwave radiative fields, and the tropospheric temperature and humidity fields, with monthly surface-upper-air correlations on the order of 0.6. Upper-level circulation patterns reveal features similar to the surface temperature fields, notably a persistent low center located over northern Canada; the cyclonic flow around the low is a tropospheric extension of the polar vortex. Colder and drier conditions are maintained within the vortex and communicated to the surface through radiative processes. The polar vortex also steers transient weather systems, the most important mechanism for horizontal heat transport, into the eastern Arctic, which results in as much as 25 W m(-2) more heat flux into the eastern Arctic than the western Arctic. A reason for the colder temperatures in the western Arctic is that the polar vortex tends to be situated downstream of the northern Rocky Mountains; this preferred location is related to orographic forcing of planetary waves. Monthly and interannual variability of winter temperatures is conditioned by the interaction of the Arctic and midlatitude circulations through the strength and position of the polar vortex. C1 UNIV WASHINGTON,JOINT INST STUDY ATMOSPHERE & OCEANS,SEATTLE,WA 98195. RP Overland, JE (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,BLDG 3,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. NR 35 TC 26 Z9 26 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1997 VL 10 IS 5 BP 821 EP 837 DI 10.1175/1520-0442(1997)010<0821:RVOWTI>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XB773 UT WOS:A1997XB77300001 ER PT J AU Soden, BJ AF Soden, BJ TI Variations in the tropical greenhouse effect during El Nino SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; WATER-VAPOR; CONVECTION; COOLNESS; HUMIDITY; CLIMATE; OCEANS AB Observations of the clear-sky outgoing longwave radiation and sea surface temperature are combined to examine the evolution of the tropical greenhouse effect from colder La Nina conditions in early 1985 to warmer El Nino conditions in late 1987. Although comparison of individual months can suggest a decrease in greenhouse trapping from cold to warm conditions, when the entire 4-yr record is considered a distinct increase in tropical-mean greenhouse trapping of similar to 2 W m(-2) is observed in conjunction with a similar to 0.4 K increase in tropical-mean sea surface temperature. This observed increase compares favorably with GCM simulations of the change in the clear-sky greenhouse effect during El Nino-Southern Oscillation (ENSO). Superimposed on top of the SST-driven change in greenhouse trapping are dynamically induced changes in tropical moisture apparently associated with a redistribution of SST during ENSO. The GCM simulations also successfully reproduce this feature, providing reassurance in the ability of GCMs to predict both dynamically and thermodynamically driven changes in greenhouse trapping. RP Soden, BJ (reprint author), PRINCETON UNIV,NOAA,GFDL,POB 308,PRINCETON,NJ 08542, USA. NR 25 TC 44 Z9 44 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1997 VL 10 IS 5 BP 1050 EP 1055 DI 10.1175/1520-0442(1997)010<1050:VITTGE>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XB773 UT WOS:A1997XB77300013 ER PT J AU Weng, FZ Grody, NC Ferraro, R Basist, A Forsyth, D AF Weng, FZ Grody, NC Ferraro, R Basist, A Forsyth, D TI Cloud liquid water climatology from the special sensor microwave/imager SO JOURNAL OF CLIMATE LA English DT Article ID OUTGOING LONGWAVE RADIATION; SEA-SURFACE TEMPERATURE; 40-50 DAY OSCILLATION; IMAGER SSM/I; WIND; RETRIEVAL; PACIFIC; OCEANS AB A Special Sensor Microwave/Imager (SSM/I) algorithm is developed to measure both cloud liquid water path (LWP) and cloud frequency (CF) over the oceans. For climate analysis, the LWP and CF parameters are computed on pentad and monthly timescales. Comparisons are made between cloud frequencies obtained from microwave and visible/infrared measurements. It is shown that the SSM/I CF correlates with International Satellite Cloud Climatology Program low- and middle-level cloudiness. Interannual variations of monthly LWP are found to be strongly correlated with Fl Nino and La Nina events. In general, positive LWP anomalies are associated with positive SST anomalies. However, positive LWP anomalies may also occur in regions of negative SST anomalies. This is probably due to an increase in warm top rain clouds, produced from low-level convergence. When pentads of outgoing longwave radiation data are compared to the LWP, they both show the detailed structure for atmospheric intraseasonal oscillations at 30-60-day periods. However, there are some interesting differences. Finally, as an important application, the monthly LWP is compared with simulations from a general circulation model. While the simulation captures the locations of observed maxima and minima, there is a large discrepancy between the model and measurement for the Northern Hemisphere in summer. C1 UNIV CORP ATMOSPHER RES,VISITING SCIENTIST PROGRAM,CAMP SPRINGS,MD. NOAA,NATL CLIMAT DATA CTR,ASHEVILLE,NC. NOAA,NESDIS,OFF RES & APPLIVAT,CLIMATE RES & APPLICAT DIV,CAMP SPRINGS,MD 20746. RP Weng, FZ (reprint author), NOAA,NESDIS,OFF RES & APPLIVAT,ATMOSPHER RES & APPLICAT DIV,5200 AUTH RD,RM 601,CAMP SPRINGS,MD 20746, USA. RI Ferraro, Ralph/F-5587-2010; Weng, Fuzhong/F-5633-2010 OI Ferraro, Ralph/0000-0002-8393-7135; Weng, Fuzhong/0000-0003-0150-2179 NR 30 TC 49 Z9 51 U1 0 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1997 VL 10 IS 5 BP 1086 EP 1098 DI 10.1175/1520-0442(1997)010<1086:CLWCFT>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XB773 UT WOS:A1997XB77300016 ER PT J AU Braun, J Epperly, SP Collazo, JA AF Braun, J Epperly, SP Collazo, JA TI Evaluation of a sonic telemetry system in three habitats of an estuarine environment SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE accuracy; angle error estimate; Cheloniidae; estuaries; North Carolina; precision; sea turtle; sonic telemetry ID TURTLES CHELONIA-MYDAS; SEA-TURTLES; ACCURACY; WATERS; ERROR AB A directional sonic telemetry system in small embayment, seagrass, and channel habitats in Core Sound, North Carolina was evaluated. We compared point location estimates calculated after correcting for system bias in three different ways: using test station (i.e. known location transmitting-receiving stations) angle errors, and using a within test site and an among test site mean angle error estimate. Estimates are necessary because, when tracking an animal, system bias cannot be corrected for using test station angle errors. In addition, telemetered animals may move beyond test areas or into different habitats. We found no significant difference (P > 0.05) among point location estimates, suggesting that a within or an among mean angle error was an acceptable estimate. Choosing the appropriate angle error estimate must be done carefully because both presented limitations. A within test site mean angle error was the more conservative approach, avoiding biases caused by significant (P<0.05) interhabitat angle error variability. An estimate containing interhabitat variability (i.e. among test site angle error) might be more robust for correcting system bias when the instrumented animal moves outside test areas or into a heterogeneous area. Seagrass habitat polygons in southern Core Sound range in size from 0.1 to 3189 ha. Attained levels of accuracy and precision from this study suggest that work could be conducted in areas where polygons are greater than or equal to 6.9 ha, which represents > 97% of the seagrass habitat in Core Sound. Although the majority (80%) of the polygons are small (< 10.0 ha), they represent < 5% of the total seagrass area. In addition, classifying use of habitat in areas where polygons are less than or equal to 6.9 ha is possible because small polygons have a contagious distribution; hence, their areas may be additive. Risks of misclassifying use of habitat can be reduced also by controlling the size of confidence areas (A,) by adjusting the distance between observers and the tracked animal. The confidence area as a function of distance can be predicted because location error varied linearly and significantly with geometric mean distance (D-g). On the basis of this relationship, D-g must be < 326 m for A(e)95 to be < 10.0 ha. (C) 1997 Elsevier Science B.V. C1 N CAROLINA STATE UNIV,N CAROLINA COOPERAT FISH & WILDLIFE RES UNIT,NATL BIOL SERV,RALEIGH,NC 27695. RP Braun, J (reprint author), NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES CTR,BEAUFORT LAB,BEAUFORT,NC 28516, USA. NR 26 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD MAY 1 PY 1997 VL 212 IS 1 BP 111 EP 121 DI 10.1016/S0022-0981(96)02737-2 PG 11 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA XC623 UT WOS:A1997XC62300008 ER PT J AU Jahncke, ML Gooch, JA AF Jahncke, ML Gooch, JA TI Sensory and chemical characteristics of selected Gulf of Mexico coastal herring species SO JOURNAL OF FOOD SCIENCE LA English DT Article DE on-board handling; sensory quality; herring; mackerel; fatty acids AB Gulf of Mexico coastal herrings may become an important alternative fisheries resource for U.S. commercial fisherman. Effects of on board handling on sensory characteristics of chub mackerel (Scomber japonicus) and rough scad (Trachurus lathami) were investigated. Proximate and fatty acid composition of chub mackerel, rough scad, round scad (Decapturus punctatus), round herring (Etrumeus teres), and silver rag (Ariomma bondi) were determined to provide nutritional and product formulation data. Chub mackerel and rough scad had similar sensory characteristics found in other commercial species, which, with proper on board handling, could be maintained during frozen storage. Proximate and fatty acid compositions of the fish varied by species, season, and year. C1 NATL MARINE FISHERIES SERV,CHARLESTON LAB,PASCAGOULA,MS 39567. RP Jahncke, ML (reprint author), NATL MARINE FISHERIES SERV,NATL SEAFOOD INSPECT LAB,3209 FREDERIC ST,PASCAGOULA,MS 39567, USA. NR 42 TC 5 Z9 5 U1 1 U2 2 PU INST FOOD TECHNOLOGISTS PI CHICAGO PA SUITE 300 221 N LASALLE ST, CHICAGO, IL 60601-1291 SN 0022-1147 J9 J FOOD SCI JI J. Food Sci. PD MAY-JUN PY 1997 VL 62 IS 3 BP 626 EP 631 DI 10.1111/j.1365-2621.1997.tb04447.x PG 6 WC Food Science & Technology SC Food Science & Technology GA XD362 UT WOS:A1997XD36200046 ER PT J AU Shue, JH Chao, JK Fu, HC Russell, CT Song, P Khurana, KK Singer, HJ AF Shue, JH Chao, JK Fu, HC Russell, CT Song, P Khurana, KK Singer, HJ TI A new functional form to study the solar wind control of the magnetopause size and shape SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLASMA OBSERVATIONS; MAGNETIC SHEAR; BOW SHOCK; ISEE 1; MAGNETOMETER; MODEL; IRM AB In this study a new functional form, r=r(0) [2/(1+cos theta)]alpha, is used to fit the size and shape of the magnetopause using crossings from ISEE 1 and 2, Active Magnetospheric Particle Tracer Explorers/Ion Release Module (AMPTE/IRM), and IMP 8 satellites. This functional form has two parameters, r(0) and alpha, representing the standoff distance and the level of tail flaring. The value r is the radial distance at an angle (theta) between the Sun-Earth line and the direction of r. It is found that r(0) varies with the interplanetary magnetic field (IMF) B-z component and has a break in the slope at B-z=0 nT. The best-fit value of r(0) decreases with increasing southward IMF B-z. For northward IMF B-z, the best-fit value of r(0) increases slightly with increasing B-z. The best-fit value of alpha increases monotonically with decreasing IMF B-z. The dynamic pressure (Dp) also changes r(0) and alpha. The parameters D-p and r(0) are related by a power law of -1/(6.6+/-0.8). The best-fit value of alpha is slightly larger for larger dynamic pressure, which implies that D-p also has a role ill flux transfer from the dayside to the nightside, but the size of this effect is small. An explicit function for the size and shape of the magnetopause, in terms of D-p and B-z, is obtained by using multiple parameter fitting in a form that is useful for operational space applications such as predicting when satellites at geosynchronous orbit will be found in the magnetosheath. C1 NATL CENT UNIV,INST SPACE SCI,CHUNGLI 32054,TAIWAN. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90095. NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,BOULDER,CO 80307. NOAA,R E SE,SPACE ENVIRONM CTR,BOULDER,CO 80303. OI Russell, Christopher/0000-0003-1639-8298 NR 23 TC 419 Z9 434 U1 6 U2 32 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1997 VL 102 IS A5 BP 9497 EP 9511 DI 10.1029/97JA00196 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WX560 UT WOS:A1997WX56000001 ER PT J AU Gupta, AK Prosser, C Cook, C Avedisian, CT AF Gupta, AK Prosser, C Cook, C Avedisian, CT TI Heat transfer effects on droplet vaporization by air preheating SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT International Mechanical Engineering Congress and Exposition - Winter Annual Meeting of the ASME CY NOV 17-22, 1996 CL ATLANTA, GA SP Amer Soc Mech Engineers C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. UNIV MARYLAND,COLLEGE PK,MD 20742. CORNELL UNIV,ITHACA,NY 14853. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD MAY PY 1997 VL 119 IS 2 BP 208 EP 208 DI 10.1115/1.2824207 PG 1 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA XB119 UT WOS:A1997XB11900008 ER PT J AU Rose, AH Etzel, SM Wang, CM AF Rose, AH Etzel, SM Wang, CM TI Verdet constant dispersion in annealed optical fiber current sensors SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article AB The Verdet constant in annealed optical fiber current sensors has been measured at wavelengths from 636 to 1320 nm. The measurements are fitted to two models, one classical and the other an expansion of the classical model that includes a nonlinear term. These measurements and models are compared to previous measurements made in optical fiber and bulk SiO2. Our measurements have an average accuracy of +/- 0.6% and an average measurement uncertainty of +/- 0.5% over the 636 to 1320 nm range. RP Rose, AH (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 19 TC 47 Z9 57 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD MAY PY 1997 VL 15 IS 5 BP 803 EP 807 DI 10.1109/50.580818 PG 5 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA WX890 UT WOS:A1997WX89000010 ER PT J AU Rose, AH AF Rose, AH TI Devitrification in annealed optical fiber SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article ID SINGLE-MODE FIBERS; CRYSTALLIZATION; GLASS; SCATTERING; BIREFRINGENCE; CRISTOBALITE; DIFFUSION AB The decrease in transmittance of annealed optical fiber has been measured versus temperature and time. The annealing loss is due to the devitrification of the glass and OH absorption in the 1200 to 1500 nm wavelength region. Both loss mechanisms propagate primarily from the surface into the core. However, to increase the OH absorption significantly, annealing times greater than 10 h are required. Fibers heated from 1000 to 1300 degrees C in an air atmosphere quickly devitrify and their transmittance approaches zero. Also, the current sensitivity of annealed fiber current sensors versus annealing time at 850 degrees C has been measured. A decrease in the current sensitivity is attributed to devitrification in the fiber. RP Rose, AH (reprint author), NATL INST STAND & TECHNOL, 325 BROADWAY, BOULDER, CO 80303 USA. NR 39 TC 30 Z9 30 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0733-8724 EI 1558-2213 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD MAY PY 1997 VL 15 IS 5 BP 808 EP 814 DI 10.1109/50.580819 PG 7 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA WX890 UT WOS:A1997WX89000011 ER PT J AU York, AE Scheffer, VB AF York, AE Scheffer, VB TI Timing of implantation in the northern fur seal, Callorhinus ursinus SO JOURNAL OF MAMMALOGY LA English DT Article DE Callorhinus ursinus; fur seals; implantation; embryonic diapause; gestation ID DELAYED IMPLANTATION; GROWTH; PHOTOPERIOD; BIRTH; REPRODUCTION AB We describe the timing of three stages of implantation in the northern fur seal, Callorhinus ursinus. The median date of formation of the implantation chamber is 14 November (+/- 1 SE = 2 days) ca. 237 days prepartum and 123 days postcopulation, of the amnion it is 22 November (+/- 1 SE = 3 days), and of the embryo, it is 29 November (+/- 1 SE = 3 days). The estimated rate of failure of implantation is 11.5% (+/- 1 SE = 0.1). Implantation dates are earlier in larger and older females. RP York, AE (reprint author), NATL MARINE MAMMAL LAB,ALASKA FISHERIES SCI CTR,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. NR 44 TC 12 Z9 13 U1 1 U2 3 PU AMER SOC MAMMALOGISTS PI PROVO PA BRIGHAM YOUNG UNIV, DEPT OF ZOOLOGY, PROVO, UT 84602 SN 0022-2372 J9 J MAMMAL JI J. Mammal. PD MAY PY 1997 VL 78 IS 2 BP 675 EP 683 DI 10.2307/1382919 PG 9 WC Zoology SC Zoology GA XB316 UT WOS:A1997XB31600039 ER PT J AU Ivester, R Danai, K Malkin, S AF Ivester, R Danai, K Malkin, S TI Cycle-time reduction in machining by recursive constraint bounding SO JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB Modeling uncertainty in machining, caused by modeling inaccuracy, noise and process time-variability due to tool wear, hinders application of traditional optimization to minimize cost or production time. Process time-variability can be overcome by adaptive control optimization (AGO) to improve machine settings in reference to process feedback so as to satisfy constraints associated with part quality and machine capability. However, ACO systems rely on process models to define the optimal conditions, so they are still affected by modeling inaccuracy and noise. This paper presents the method of Recursive Constraint Bounding (RCB2) which is designed to cope with modeling uncertainty as well as process time-variability. RCB2 uses a model, similar to other ACO methods. However, it considers confidence levels and noise buffers to account for degrees of inaccuracy and randomness associated with each modeled constraint. RCB2 assesses optimality by measuring the slack in individual constraints after each part is completed (cycle), and then redefines the constraints to yield more aggressive machine settings for the next cycle. The application of RCB2 is demonstrated here in reducing cycle-time for internal cylindrical plunge grinding. C1 UNIV MASSACHUSETTS,DEPT MECH ENGN,AMHERST,MA 01003. RP Ivester, R (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 14 TC 10 Z9 10 U1 3 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1087-1357 J9 J MANUF SCI E-T ASME JI J. Manuf. Sci. Eng.-Trans. ASME PD MAY PY 1997 VL 119 IS 2 BP 201 EP 207 DI 10.1115/1.2831096 PG 7 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA XC318 UT WOS:A1997XC31800009 ER PT J AU Garzoli, SL Goni, GJ Mariano, AJ Olson, DB AF Garzoli, SL Goni, GJ Mariano, AJ Olson, DB TI Monitoring the upper southeastern Atlantic transports using altimeter data SO JOURNAL OF MARINE RESEARCH LA English DT Article ID INVERTED ECHO SOUNDERS; AGULHAS CURRENT; CIRCULATION; HEIGHT; OCEAN AB A large in-situ data set, collected in the southeastern Atlantic Ocean, is merged with the TOPEX/POSEIDON altimeter observations in order to verify the use of altimeter data in monitoring the transports of the Agulhas/Benguela system. Comparisons between altimeter observations and either moored current meters or inverted echo sounder measurements shows that the sea-surface elevation anomaly is significantly correlated with the thermocline depth and the surface dynamic height, respectively. Knowing the least-squares regression parameters, it is possible to calculate the transports by using geostrophy and either a two-layer or a continuously-stratified model. The transports obtained from fits of dynamic height to altimeter sea-surface height are similar to the ones calculated with the moored instruments. In the southern part of the area under analysis, around 35S, close to the Agulhas retroflection, the transports obtained from the two-layer model are overestimated. Across the Benguela Current, at 30S, transports are still overestimated but of the same order as the measured ones. In this part of the region, the two-layer model can be successfully used to calculate the total and barotropic transports of the Benguela Current. Analysis of the three years of geostrophic transport obtained from the altimeter data indicate that the mean Benguela Current transport does not change interannually more than 20%. However, the primary interannual variability derives from the source water that forms the Benguela Current. C1 UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MIAMI,FL 33149. RP Garzoli, SL (reprint author), NOAA,ATLANTIC OCEANOG & METEOROL LAB,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Garzoli, Silvia/A-3556-2010; Goni, Gustavo/D-2017-2012; OI Garzoli, Silvia/0000-0003-3553-2253; Goni, Gustavo/0000-0001-7093-3170; Olson, Donald/0000-0001-7180-5672 NR 21 TC 31 Z9 31 U1 0 U2 1 PU KLINE GEOLOGY LABORATORY PI NEW HAVEN PA YALE UNIV, NEW HAVEN, CT 06520 SN 0022-2402 J9 J MAR RES JI J. Mar. Res. PD MAY PY 1997 VL 55 IS 3 BP 453 EP 481 DI 10.1357/0022240973224355 PG 29 WC Oceanography SC Oceanography GA XH680 UT WOS:A1997XH68000002 ER PT J AU Reed, RK Stabeno, PJ AF Reed, RK Stabeno, PJ TI Long-term measurements of flow near the Aleutian islands SO JOURNAL OF MARINE RESEARCH LA English DT Article ID ALASKAN STREAM; BERING SEA; BASIN AB In summer 1995, the Alaskan Stream at 173.5W was very intense; the peak geostrophic speed was similar to 125 cm s(-1), and the computed volume transport above 1000 db, referred to 1000 db, was 9 x 10(6) m(3) s(-1). Flow north of the central Aleutians was shallow, convoluted and weak (2-3 x 10(6) m(3) s(-1)). A sequence of CTD casts across Amukta Pass, spaced irregularly in time during 1993-1996, showed a mean northward (southward) geostrophic transport of 1.0 (0.4) x 10(6) m(3) s(-1), for a net flow into the Bering Sea of 0.6 x 10(6) m(3) s(-1). The source of this flow was the Alaskan Stream except in 1995, when it was Bering Sea water. Results from two 13-month current moorings west and east of the pass were quite different. To the west, flow was weak and variable and appeared to have a barotropic component. To the east, flow was stronger and unidirectional eastward. RP Reed, RK (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. NR 12 TC 16 Z9 16 U1 0 U2 2 PU KLINE GEOLOGY LABORATORY PI NEW HAVEN PA YALE UNIV, NEW HAVEN, CT 06520 SN 0022-2402 J9 J MAR RES JI J. Mar. Res. PD MAY PY 1997 VL 55 IS 3 BP 565 EP 575 DI 10.1357/0022240973224328 PG 11 WC Oceanography SC Oceanography GA XH680 UT WOS:A1997XH68000006 ER PT J AU Atkinson, R Baulch, DL Cox, RA Hampson, RF Kerr, JA Rossi, MJ Troe, J AF Atkinson, R Baulch, DL Cox, RA Hampson, RF Kerr, JA Rossi, MJ Troe, J TI Evaluated kinetic, photochemical and heterogeneous data for atmospheric chemistry .5. IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Review DE air pollution; atmospheric chemistry; chemical kinetics; data evaluation; gas phase; heterogeneous atmospheric reactions; photoabsorption cross-section, photochemistry; quantum yield; rate coefficient ID ABSORPTION CROSS-SECTIONS; ABSOLUTE RATE CONSTANTS; PHOTOLYSIS-RESONANCE FLUORESCENCE; OH RADICAL REACTIONS; LASER-INDUCED FLUORESCENCE; BAND OSCILLATOR-STRENGTHS; SCHUMANN-RUNGE BANDS; SULFURIC-ACID SURFACES; MASS ACCOMMODATION COEFFICIENT; ATOM-INITIATED OXIDATION AB This paper updates and extends previous critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992)]. 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 658 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each 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. 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 data on enthalpies of formation of the reactant and product species. We have also included for the first time in this series of evaluations a section on heterogeneous reactions of importance in atmospheric chemistry. (C) 1997 American Institute of Physics and American Chemical Society. C1 UNIV CALIF RIVERSIDE, DEPT SOIL & 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. NATL INST STAND & TECHNOL, CHEM KINET DATA CTR, GAITHERSBURG, MD 20899 USA. SWISS FED INST TECHNOL, ETH, EAWAG, CH-8600 DUBENDORF, SWITZERLAND. ECOLE POLYTECH FED LAUSANNE, DGR, LAB POLLUT ATMOSPHER & SOL, CH-1015 LAUSANNE, SWITZERLAND. UNIV GOTTINGEN, INST PHYS CHEM, D-37077 GOTTINGEN, GERMANY. RP Atkinson, R (reprint author), UNIV CALIF RIVERSIDE, STATEWIDE AIR POLLUT RES CTR, RIVERSIDE, CA 92521 USA. RI ROSSI, Michel J./C-7878-2013 OI ROSSI, Michel J./0000-0003-3504-695X NR 1596 TC 707 Z9 719 U1 13 U2 125 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD MAY-JUN PY 1997 VL 26 IS 3 BP 521 EP 1011 PG 491 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA XB683 UT WOS:A1997XB68300001 ER PT J AU Eberhard, J Howard, CJ AF Eberhard, J Howard, CJ TI Rate coefficients for the reactions of some C-3 to C-5 hydrocarbon peroxy radicals with NO SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TERT-BUTYL ETHER; GAS-PHASE; RATE CONSTANTS; ABSORPTION-SPECTRUM; MOLECULAR-OXYGEN; PULSE-RADIOLYSIS; KINETICS; CH3O2; ALKYL; 295-K AB The rate coefficients for the gas-phase reactions of allyl-, tert-butyl-, cyclopentyl-, and 2-pentylperoxy radicals with NO have been measured at 297 +/- 2 K in a flow tube reactor using chemical ionization mass spectrometric (CIMS) detection of the peroxy radical. The hydrocarbon radicals were produced through the dissociation of the parent alkyl iodide in a low-power radio frequency (rf) discharge. The unimolecular decomposition of the c-pentyl radicals in the rf discharge yielded allyl radicals, The peroxy radicals were generated by reacting the hydrocarbon radicals with O-2. The rate coefficients were found to be, in units of 10(-12) cm(3) molecule(-1) s(-1), 10.5 +/- 1.8, 7.9 +/- 1.3, 10.9 +/- 1.9, and 8.0 +/- 1.4 for the reactions of NO with CH2=CHCH2O2, t-C4H9O2, C-C5H9O2, and 2-C5H11O2 radicals, respectively. The results of this study together with our previous results for nonsubstituted C-1-C-3 alkyl peroxy radicals suggest no significant trend in the rate coefficients with size and branching of the radicals, This is in contradiction to some previous studies, which found that the rate coefficients decrease with increasing radical size and complexity. Some implications of this finding for atmospheric chemistry are briefly discussed. C1 NOAA,ERL,AERON LAB,BOULDER,CO 80303. NR 50 TC 45 Z9 45 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 1 PY 1997 VL 101 IS 18 BP 3360 EP 3366 DI 10.1021/jp9640282 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WX119 UT WOS:A1997WX11900024 ER PT J AU Russell, TP Piermarini, GJ Miller, PJ AF Russell, TP Piermarini, GJ Miller, PJ TI Pressure/temperature and reaction phase diagram for dinitro azetidinium dinitramide SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID THERMAL-DECOMPOSITION; AMMONIUM DINITRAMIDE; PRESSURE; KBAR; CHEMISTRY; CELL AB The pressure/temperature and reaction phase diagram for dinitro azetidinium dinitramide (DNAZ-DN) has been delineated using a high-pressure diamond anvil cell with Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and optical polarizing light microscopy. The phase diagram was determined between ambient pressure and 10.0 GPa over the temperature range from -75 degrees C to decomposition temperatures or > 150 degrees C, The phase diagram delineates the melt curve for alpha-DNAZ-DN, a reversible phase transformation in alpha-DNAZ-DN forming a new high-pressure polymorph, beta-DNAZ-DN, and also identifies the pressure and temperature conditions for solid state decomposition of beta-DNAZ-DN. FTIR and Raman spectra were obtained for both the alpha and beta phases as a function of pressure at room temperature. The new high-pressure beta polymorph could not be retrieved to ambient conditions. C1 NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899. USN,CTR SURFACE WARFARE,SILVER SPRING,MD 20901. RP Russell, TP (reprint author), USN,RES LAB,DIV CHEM,CODE 6110,WASHINGTON,DC 20375, USA. NR 19 TC 3 Z9 3 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 1 PY 1997 VL 101 IS 18 BP 3566 EP 3570 DI 10.1021/jp962826m PG 5 WC Chemistry, Physical SC Chemistry GA WX113 UT WOS:A1997WX11300019 ER PT J AU Vaughan, SL Molinari, RL AF Vaughan, SL Molinari, RL TI Temperature and salinity variability in the deep western boundary current SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID NORTH-ATLANTIC OCEAN; LABRADOR SEA; ABACO-ISLAND; 26.5-DEGREES-N; BAHAMAS; EAST; CIRCULATION; TRANSPORT AB A ten-year time series (1984-1993) of repeat hydrographic sections from offshore Abaco Island, the Bahamas (26.5 degrees N), is used to define the mean and time dependent characteristics of the deep western boundary current (DWBC). The DWBC flow is divided into four vertical layers based on chlorofluorocarbon (CFC) concentration and formation regions (upper layer: CFC core, theta similar to 3.9 degrees-5.0 degrees C; second layer: classical Labrador Sea Water, a similar to 3.2 degrees-3.9 degrees C; third layer: CFC minimum, theta similar to 2.4 degrees-3.2 degrees C; deepest layer: CFC core, theta similar to 1.85 degrees-2.4 degrees C). Time series analysis of mean layer properties and their anomalies showed that the temperature and salinity of each layer did not increase or decrease monotonically with time. Variations in temperature and salinity were characterized by 2-3-yr period oscillations. Variability between years is illustrated by subtracting repeat sections of temperature and salinity along levels of both constant pressure and constant potential density. To determine an original water mass modification that could be responsible for the observed variability in the section differences, an analytical method, which uses both types of differencing schemes, was applied to the DWBC data. Variability in the upper layer between 1987 and 1993 was shown to originate primarily from an increased salinity of the source waters for this layer. Variability in the second layer was shown to arise from a combination of cooling and salinification. Variability in the two deepest layers seemed to be almost entirely due to vertical movement of the isopycnals. Increases in potential temperature and salinity observed in a sublayer of the second layer defined by sigma(1.5) similar to 34.68-34.74 (classical Labrador Sea Water) from 1991 to 1993 was shown to be mainly the result of cooling. It is suggested that this cooling may have originally occurred in the central Labrador Sea during the period of active deep water renewal in the early 1970s. C1 NATL OCEAN & ATMOSPHER ADM,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL. RP Vaughan, SL (reprint author), PRINCE WILLIAM SOUND SCI CTR,POB 705,CORDOVA,AK 99574, USA. NR 21 TC 11 Z9 11 U1 2 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD MAY PY 1997 VL 27 IS 5 BP 749 EP 761 DI 10.1175/1520-0485(1997)027<0749:TASVIT>2.0.CO;2 PG 13 WC Oceanography SC Oceanography GA WZ308 UT WOS:A1997WZ30800009 ER PT J AU Cummins, PF Oey, LY AF Cummins, PF Oey, LY TI Simulation of barotropic and baroclinic tides off northern British Columbia SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID INTERNAL TIDE; MODEL; CIRCULATION; GENERATION; STRAIT; SHELF; COAST AB The tidal response of northern British Columbia coastal waters is studied through simulations with a three-dimensional, prognostic, primitive equation model. The model is forced at the boundaries with the leading semidiurnal and diurnal constituents and experiments with stratified and homogeneous fluid are compared. The barotropic response shows good agreement with previously published studies of tides in the region. A comparison with tide gauge measurements indicates that average relative rms differences between observations and the model surface elevation field are less than 5% for the largest constituents. An internal tide is generated in cases where the model is initialized with a vertical stratification. Diagnostic calculations of the baroclinic energy flux are used to identify regions of generation and propagation of internal tidal energy. With a representative summer stratification, the integrated offshore flux is about 0.5 gigawatts, higher than previously estimated from theoretical models. Comparisons between observed and modeled M-2 current ellipses are discussed for several moorings and demonstrate the significant influence of the internal tide. C1 PRINCETON UNIV, PROGRAM ATMOSPHER & OCEAN SCI, PRINCETON, NJ 08544 USA. RP FISHERIES & OCEANS CANADA INST OCEAN SCI, POB 6000, 9860 W SAANICH RD, SIDNEY, BC V8L 4B2, CANADA. NR 33 TC 112 Z9 117 U1 0 U2 4 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 MAY PY 1997 VL 27 IS 5 BP 762 EP 781 DI 10.1175/1520-0485(1997)027<0762:SOBABT>2.0.CO;2 PG 20 WC Oceanography SC Oceanography GA WZ308 UT WOS:A1997WZ30800010 ER PT J AU Thompson, A Early, EA DeLuisi, J Disterhoft, P Wardle, D Kerr, J Rives, J Sun, YC Lucas, T Mestechkina, T Neale, P AF Thompson, A Early, EA DeLuisi, J Disterhoft, P Wardle, D Kerr, J Rives, J Sun, YC Lucas, T Mestechkina, T Neale, P TI The 1994 North American interagency intercomparison of ultraviolet monitoring spectroradiometers SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE environmental monitoring; intercomparison; solar ultraviolet; spectroradiometers AB Concern over stratospheric ozone depletion has prompted several government agencies in North America to establish networks of spectroradiometers for monitoring solar ultraviolet irradiance at the surface of the Earth. To assess the ability of spectroradiometers to accurately measure solar ultraviolet irradiance, and to compare the results between instruments of different monitoring networks, the first North American Intercomparison of Ultraviolet Monitoring Spectroradiometers was held September 19-29, 1994 at Table Mountain outside Boulder, Colorado, USA. This Intercomparison was coordinated by the National Institute of Standards and Technology and the National Oceanic and Atmospheric Administration (NOAA). Participating agencies were the Environmental Protection Agency, National Science Foundation, Smithsonian Environmental Research Center, and Atmospheric Environment Service, Canada. Instruments were characterized for wavelength accuracy, bandwidth, stray-light rejection, and spectral irradiance responsivity, the latter with a NIST standard lamp calibrated to operate in the horizontal position. The spectral irradiance responsivity was determined once indoors and twice outdoors, and demonstrated that, while the responsivities changed upon moving the instruments, they were relatively stable when the instruments remained outdoors. Synchronized spectral scans of the solar irradiance were performed over several days. Using the spectral irradiance responsivities determined with the NIST standard lamp, and a simple convolution technique to account for the different bandwidths of the instruments, the measured solar irradiances agreed within 5%. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NOAA, Boulder, CO 80303 USA. Environm Canada, Atomospher Environm Serv, Toronto, ON M3H 5T4, Canada. Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. Biospher Instruments Inc, San Diego, CA 92110 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Thompson, A (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 16 TC 19 Z9 19 U1 0 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAY-JUN PY 1997 VL 102 IS 3 BP 279 EP 322 DI 10.6028/jres.102.021 PG 44 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2817 UT WOS:000168726400001 PM 27805148 ER PT J AU Ohno, Y AF Ohno, Y TI Improved photometric standards and calibration procedures at NIST SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE calibration; candela; illuminance; integrating sphere; lumen; luminance; luminous flux; luminous intensity; lux AB NIST has recently established a detector-based luminous intensity unit (candela, ed), which is derived from the NIST absolute cryogenic radiometer. Subsequently, the luminous flux unit (lumen, Im) and the luminance unit (cd/m(2)) have been established based on the detector-based candela, and now all the NIST photometric units are tied to the cryogenic radiometer. The illuminance unit is realized and maintained on five standard photometers. The large dynamic range of the standard photometers eliminates the need for maintaining many working standard lamps of various wattages. The luminous intensities of lamps are determined from the illuminances measured with these photometers and the distances measured with a linear encoder system. Transfer photometers and illuminance meters are calibrated by direct comparison with the standard photometers with no distance measurements involved. The luminous flux unit is realized using an absolute integrating sphere method newly developed at NIST. The luminance unit is realized on an integrating sphere source, which is used for calibration of other luminance sources and luminance meters. These detector-based methods have made it possible to reduce the uncertainties of photometric calibrations and to provide more varieties of photometric calibration services at NIST. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Ohno, Y (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 9 TC 12 Z9 12 U1 1 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAY-JUN PY 1997 VL 102 IS 3 BP 323 EP 331 DI 10.6028/jres.102.022 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2817 UT WOS:000168726400002 PM 27805149 ER PT J AU Mechels, SE Schlager, JB Franzen, DL AF Mechels, SE Schlager, JB Franzen, DL TI Accurate measurements of the zero-dispersion wavelength in optical fibers SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE chromatic dispersion; dispersion slope; nonlinear four-wave mixing; optical fiber; optical fiber bandwidth; polarization-mode dispersion; Standard Reference Material; telecommunication systems; zero-dispersion wavelength AB We have developed a frequency-domain phase shift system for measuring the zero-dispersion wavelength and the dispersion slope of single-mode optical fibers. A differential phase shift method and nonlinear four-wave mixing technique were also investigated. The frequency-domain phase shift method is used to produce Standard Reference Materials that have their zero-dispersion wavelengths characterized with an expanded uncertainty (k - 2) of +/- 0.060 nm. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Mechels, SE (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 39 TC 25 Z9 27 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 MAY-JUN PY 1997 VL 102 IS 3 BP 333 EP 347 DI 10.6028/jres.102.023 PG 15 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2817 UT WOS:000168726400003 PM 27805150 ER PT J AU Bartel, TW Yaniv, SL AF Bartel, TW Yaniv, SL TI Creep and creep recovery response of load cells tested according to US and international evaluation procedures SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE creep; creep recovery; force measurement; load cell AB The 60 min creep data from National Type Evaluation Procedure (NTEP) tests performed at the National Institute of Standards and Technology (NIST) on 65 load cells have been analyzed in order to compare their creep and creep recovery responses, and to compare the 60 min creep with creep over shorter time periods. To facilitate this comparison the data were fitted to a multiple-term exponential equation, which adequately describes the creep and creep recovery responses of load cells. The use of such a curve fit reduces the effect of the random error in the indicator readings on the calculated values of the load cell creep. Examination of the fitted curves show that the creep recovery responses, after inversion by a change in sign, are generally similar in shape to the creep response, but smaller in magnitude. The average ratio of the absolute value of the maximum creep recovery to the maximum creep is 0.86; however, no reliable correlation between creep and creep recovery can be drawn from the data. The fitted curves were also used to compare the 60 min creep of the NTEP analysis with the 30 min creep and other parameters calculated according to the Organization Internationale de Metrologie Legale (OIML) R 60 analysis. The average ratio of the 30 min creep value to the 60 min value is 0.84. The OIML class C creep tolerance is less than 0.5 of the NTEP tolerance for classes III and III L. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Bartel, TW (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 11 TC 5 Z9 6 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAY-JUN PY 1997 VL 102 IS 3 BP 349 EP 362 DI 10.6028/jres.102.024 PG 14 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2817 UT WOS:000168726400004 PM 27805151 ER PT J AU Fanney, AH Dougherty, BP AF Fanney, AH Dougherty, BP TI A photovoltaic solar water heating system SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB A novel solar water heating system was patented in 1994. This system uses photovoltaic cells to generate electrical energy that is subsequently dissipated in multiple electric resistive heating elements. A microprocessor controller continually selects the appropriate heating elements such that the resistive load causes the photovoltaic array to operate at or near maximum power. Unlike other residential photovoltaic systems, the photovoltaic solar Water heating system does not require an inverter to convert the direct current supplied by the photovoltaic array to an alternating current or a battery system for storage. It uses the direct current supplied by the photovoltaic array and the inherent storage capabilities of a residential water heater. A photovoltaic solar hot water system eliminates the components most often associated with the failures of solar thermal hot water systems. Although currently more expensive than a solar thermal hot water system, the continued decline of photovoltaic cell prices is likely to make this system competitive with solar thermal hot water systems within the next decade. This paper describes the system, discusses the advantages and disadvantages relative to solar thermal water heating systems, reviews the various control strategies which have been considered, and presents experimental results for two full-scale prototype systems. RP Fanney, AH (reprint author), NATL INST STAND & TECHNOL,BLDG ENVIRONM DIV,GAITHERSBURG,MD 20899, USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD MAY PY 1997 VL 119 IS 2 BP 126 EP 133 DI 10.1115/1.2887891 PG 8 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA XA716 UT WOS:A1997XA71600006 ER PT J AU Lee, BP Cardy, J AF Lee, BP Cardy, J TI Renormalization group study of the A+B->0 diffusion-limited reaction (vol 80, pg 971, 1995) SO JOURNAL OF STATISTICAL PHYSICS LA English DT Correction, Addition AB A recent argument of Oerding shows that our calculation of the quantity Delta, which determines the amplitude of the asymptotic decay of the particle density in 2 < d < 4, was in error. Instead it is simply given by Delta = n(0) the initial density, for uncorrelated initial conditions. C1 UNIV OXFORD,OXFORD OX1 3NP,ENGLAND. UNIV OXFORD ALL SOULS COLL,OXFORD OX1 3NP,ENGLAND. RP Lee, BP (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 7 TC 21 Z9 21 U1 0 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD MAY PY 1997 VL 87 IS 3-4 BP 951 EP 954 DI 10.1007/BF02181256 PG 4 WC Physics, Mathematical SC Physics GA XK436 UT WOS:A1997XK43600024 ER PT J AU Hoshikuma, J Kawashima, K Nagaya, K Taylor, AW AF Hoshikuma, J Kawashima, K Nagaya, K Taylor, AW TI Stress-strain model for confined reinforced concrete in bridge piers SO JOURNAL OF STRUCTURAL ENGINEERING-ASCE LA English DT Article ID DUCTILITY; STRENGTH; COLUMNS AB In this paper, a stress-strain model of concrete that takes confinement effects into account is developed, based on the results of a series of compression loading tests of reinforced concrete column specimens. The specimens have circular, square, and wall-type cross sections, with various arrangements of hoop reinforcement so as to cover practical bridge column sections designed in Japan. Test results showed that three parameters-peak stress, strain at peak stress, and deteriorating rate-are significant factors for the stress-strain curve of confined concrete. These parameters were analyzed statistically based on test data and equations for estimating them were proposed. An equivalent confined section was also proposed to evaluate effect of cross ties in wall-type cross section. Test results were compared with both the proposed model and existing models. The comparison showed that the predicted stress-strain relation by the proposed model provides better agreement with the experimental results than existing models. C1 TOKYO INST TECHNOL,DEPT CIVIL ENGN,TOKYO 152,JAPAN. NATL INST STAND & TECHNOL,STRUCT DIV,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899. RP Hoshikuma, J (reprint author), MINIST CONSTRUCT,PUBL WORKS RES INST,EARTHQUAKE ENGN DIV,TSUKUBA,IBARAKI 305,JAPAN. NR 16 TC 113 Z9 131 U1 0 U2 10 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9445 J9 J STRUCT ENG-ASCE JI J. Struct. Eng.-ASCE PD MAY PY 1997 VL 123 IS 5 BP 624 EP 633 DI 10.1061/(ASCE)0733-9445(1997)123:5(624) PG 10 WC Construction & Building Technology; Engineering, Civil SC Construction & Building Technology; Engineering GA WV716 UT WOS:A1997WV71600012 ER PT J AU Wang, JCM Splett, JD AF Wang, JCM Splett, JD TI Consensus values and reference values illustrated by the Charpy machine certification program SO JOURNAL OF TESTING AND EVALUATION LA English DT Article DE consensus value; reference value; weighted averages; variance components; notched-bar testing; reference specimens; Charpy machine certification program; pendulum impact machines; impact testing ID WEIGHTING FACTORS AB We present an overview of consensus values and reference values for various situations and apply the computational methods to data from the Charpy machine certification program administered by the National Institute of Standards and Technology. Candidate Charpy machines are certified by comparing a reference value to the average of a set of verification specimens measured by the candidate machine. Currently, the reference value is the average of three averages observed for measurements taken using three Charpy reference machines. However, the simple average, which does not account for differences among reference machines, may not be the optimal method of computing the reference value for every situation. We describe four different methods based on the simple average, the average weighted by sample size, the weighted average that takes into account machine differences, and the weighted average when machine biases are known, for computing the consensus value and its uncertainty. We also present two methods for computing reference values using weighted and unweighted averages. The techniques and recommendations described in the paper are applicable to consensus value and reference value problems in general. RP Wang, JCM (reprint author), NATL INST STAND & TECHNOL,STAT ENGN DIV,COMP & ALLIED MATH LAB,BOULDER,CO 80303, USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD MAY PY 1997 VL 25 IS 3 BP 308 EP 314 PG 7 WC Materials Science, Characterization & Testing SC Materials Science GA XB875 UT WOS:A1997XB87500005 ER PT J AU Munro, RG AF Munro, RG TI Material specifications of advanced ceramics and other issues in the use of property databases with corrosion analysis models SO JOURNAL OF TESTING AND EVALUATION LA English DT Article; Proceedings Paper CT E49 Symposium on Chemical Data Standards - Database, Data Interchange, and Information Systems CY MAY 10-11, 1995 CL COLUMBUS, OH DE ceramics; corrosion; database; materials specification AB The growing interest in linking analysis models with distributed materials property databases gives rise to new database design requirements. This paper discusses the conditions encountered in the modeling of the corrosion of a ceramic material as a time-dependent phenomenon. fn the corrosion of ceramics, numerous distinct contributing processes occur in different regions of the specimen simultaneously. These different regions usually have different compositions, native microstructures, and environmentally intrusive agents. Both predictive modeling efforts and post-test diagnostic analyses, therefore, require chemical and physical property data that are related to the specific material substructures. There are significant problems in the practice of representing such information in general-purpose materials property databases. The essential issues pertain to the form of the representation, the accessibility of the data, and the uniqueness of the value set. This paper addresses these issues in the context of a multipurpose database into which access is needed by an automated, external, analysis program. The corrosion of silicon carbide is used as a prototypic case in discussing the standards for the database, the expectations of the user, and the implications of the practical design of the property database. It is concluded that the required analysis tools include the model with constraints on the material and the environment, a property database that distinguishes the material's substructure types and locations, a reactions database for all significantly reacting species in the system, and an expert system interface to assess the performance level options available by means of the property data. RP Munro, RG (reprint author), NIST,DIV CERAM,A256,BLDG 223,GAITHERSBURG,MD 20899, USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD MAY PY 1997 VL 25 IS 3 BP 349 EP 353 PG 5 WC Materials Science, Characterization & Testing SC Materials Science GA XB875 UT WOS:A1997XB87500011 ER PT J AU Voronovich, AG Shang, EC AF Voronovich, AG Shang, EC TI Numerical simulations with horizontal-refraction-modal tomography .1. Adiabatic propagation SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID OCEAN ACOUSTIC TOMOGRAPHY AB Numerical simulations on retrieving the 3-D structure of the sound-speed inhomogeneities based on data on the horizontal refraction angle (HRA) of acoustic modes have been performed. The inversion proceeds in two stages. At the first stage the values of propagation constants of different acoustic modes at the nodes of a horizontal grid are calculated. The corresponding procedure represents a linear 2-D problem which is solved for different modes independently. At the second stage the coefficients of the expansion of the variation of the sound-speed profile with respect to some set of empirical orthogonal functions are calculated based on already determined values of propagation constants. This stage represents a 1-D nonlinear problem which is solved for different nodes of the horizontal grid independently. When error-free HRA data were used in the numerical simulations, the 3-D sound-speed field was retrieved perfectly. Then the HRA data were artificially distorted with random errors. It was found that the relative error of the retrieved values of the propagation constant of modes is proportional to the error in HRA (expressed in radians). Corresponding relative error in retrieved values of sound speed is in its turn proportional to the relative error in propagation constants. When the level of HRA error has been chosen according to the level arising from distortions caused by internal waves, the rms error in the retrieved sound-speed values for the situation considered appeared to be about 0.7 m/s. (C) 1997 Acoustical Society of America. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. RP Voronovich, AG (reprint author), NOAA,ENVIRONM TECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 7 TC 6 Z9 10 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAY PY 1997 VL 101 IS 5 BP 2636 EP 2643 DI 10.1121/1.418504 PN 1 PG 8 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA WZ041 UT WOS:A1997WZ04100026 ER PT J AU Lu, CG Ciesielski, PE Schubert, WH AF Lu, CG Ciesielski, PE Schubert, WH TI Geostrophic and ageostrophic circulations in midlatitude squall lines SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MESOSCALE CONVECTIVE SYSTEMS; 10-11 JUNE 1985; POTENTIAL VORTICITY; REAR-INFLOW; STRATIFORM PRECIPITATION; NUMERICAL-SIMULATION; MODEL; INSTABILITY; EVOLUTION; STABILITY AB The Eliassen transverse circulation equation is derived from the set of f-plane, semigeostrophic, slab-symmetric equations with the inclusion of both diabatic hearing and ambient shear effects. Numerical integrations of this model in geostrophic coordinates are performed in the context of a typical midlatitude squall line characterized by a leading convective line and a trailing stratiform rain region. Some dynamical insights are provided by these integrations in conjunction with the theoretical framework, which seem to be unavailable by primitive-equation model simulations. A more complete dynamical picture of a squall line circulation system is revealed from this study: a balanced midlevel horizontal vortex coupled with an ageostrophic transverse circulation in the normal-line plane. This configuration suggests an interaction between two distinct dynamical scales, that is, the scales with geostrophic and ageostrophic-like motions, both of which play important roles in mesoscale convective systems. The internal and external physical processes that affect the ageostrophic transverse circulation are further discussed. C1 COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523. RP Lu, CG (reprint author), NOAA,ERL,FORECAST SYST LAB,BOULDER,CO 80303, USA. NR 35 TC 4 Z9 4 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 1 PY 1997 VL 54 IS 9 BP 1218 EP 1230 DI 10.1175/1520-0469(1997)054<1218:GAACIM>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX110 UT WOS:A1997WX11000007 ER PT J AU Hayashi, Y Golder, DG AF Hayashi, Y Golder, DG TI United mechanisms for the generation of low- and high-frequency tropical waves .1. Control experiments with moist convective adjustment SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Review ID EVAPORATION-WIND FEEDBACK; ROSSBY-GRAVITY-WAVES; MADDEN-JULIAN OSCILLATION; FORCED EQUATORIAL PERTURBATIONS; 40-50 DAY OSCILLATION; SUPER CLOUD CLUSTERS; LARGE-SCALE DYNAMICS; QBO-LIKE OSCILLATION; AQUA PLANET MODEL; CIRCULATION MODEL AB To examine several mechanisms for the generation of low- and high-frequency tropical waves, numerical experiments are conducted using an idealized nine-level R21 spectral model with the original scheme of moist convective adjustment (MCA). The model prescribes globally uniform, time-independent distributions of sea surface temperatures and insolation, thereby excluding stationary waves and extratropical baroclinic waves. The idealized model, however, still produces tropical intraseasonal oscillations, superclusters, Kelvin waves, and mixed Rossby-gravity waves. When eliminating the wind fluctuations in the parameterized surface fluxes of latent and sensible heat, the intraseasonal oscillations are profoundly weakened while other waves are not substantially weakened. Subsequently, the MCA scheme is modified to neutralize any conditionally unstable stratification that would otherwise develop during periods of nonsaturation. This modification suppresses the part of the MCA process that neutralizes, upon saturation, any preexisting unstable stratification. In spite of the presence of moisture convergence, all tropical transient waves then disappear, in contrast to the wave-CISK (conditional instability of the second kind) mechanism. The above results are consistent with the united mechanisms proposed as follows. Intraseasonal oscillations are maintained primarily through the evaporation-wind feedback mechanism. Other waves are maintained primarily through the ''saturation-triggering mechanism'' and/or the lateral-triggering mechanism. The saturation-triggering mechanism hypothesizes that transient waves can be triggered by the intermittent onset of nonequilibrium moist convection, upon saturation, to neutralize any preexisting unstable stratification. RP PRINCETON UNIV, GEOPHYS FLUID DYNAM LAB, NOAA, POB 308, PRINCETON, NJ 08542 USA. NR 158 TC 28 Z9 28 U1 1 U2 4 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 1997 VL 54 IS 9 BP 1262 EP 1276 DI 10.1175/1520-0469(1997)054<1262:UMFTGO>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX110 UT WOS:A1997WX11000010 ER PT J AU Zhou, P Papanek, P Lee, R Fischer, JE Kamitakahara, WA AF Zhou, P Papanek, P Lee, R Fischer, JE Kamitakahara, WA TI Local structure and vibrational spectroscopy of disordered carbons for Li batteries: Neutron scattering studies SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID GRAPHITE COMPOUND LIC6; CARBONACEOUS MATERIALS; LITHIUM INSERTION; INTERCALATION; SYSTEMS AB Compositions, local atomic structures, porosity, and vibrational dynamics of carbons obtained by pyrolyzing epoxy novolak resins at 650 and 1000 degrees C are investigated using several neutron scattering techniques. The ultimate goal is to understand the origin of the very high capacity for Li uptake exhibited by these materials. Neutron radial distribution function analysis and incoherent inelastic scattering show that the structural motif is a planar hexagonal graphene fragment similar to 10 Angstrom on a side, with edge carbons terminated by single hydrogen atoms and random stacking between fragments. Small-angle neutron scattering reveals substantial porosity on a length scale comparable to the size of the graphene fragments. Coupled with computer simulations, these results are consistent with two proposed mechanisms for unusually high Li capacity one analogous to conventional intercalation but with Li on both sides of isolated graphene fragments, the other involving bonding of Li to H-terminated edge carbons. C1 UNIV PENN,RES STRUCT MATTER LAB,PHILADELPHIA,PA 19104. NATL INST STAND & TECHNOL,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. RP Zhou, P (reprint author), UNIV PENN,DEPT MAT SCI & ENGN,3231 WALNUT ST,PHILADELPHIA,PA 19104, USA. NR 38 TC 30 Z9 30 U1 1 U2 15 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1997 VL 144 IS 5 BP 1744 EP 1750 DI 10.1149/1.1837672 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XD006 UT WOS:A1997XD00600051 ER PT J AU Shaw, JA Churnside, JH AF Shaw, JA Churnside, JH TI Fractal laser glints from the ocean surface SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article DE fractals; self-similarity; statistical optics; ocean optics; sea-surface roughness ID SEA; WATER; WAVES AB Time series of laser glint counts from the ocean surface exhibit fractal behavior. Glint-count histogram widths do not follow Gaussian statistics, and histogram shapes are approximately log normal. Fractal dimensions for the statistically self-similar glint-count time series are found from the power spectra, which have an inverse power-law form. Glint counts in one spatial dimension from a linearly scanning laser and glint counts in two spatial dimensions from a laser glint imager behave similarly. In both sets of data, spectral density peaks exist at frequencies corresponding to swell and long wind waves. This implies that the glint-count process contains information related to long-wave modulation of surface roughness. (C) 1997 Optical Society of America. RP Shaw, JA (reprint author), NOAA,ENVIRONM TECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Churnside, James/H-4873-2013 NR 20 TC 7 Z9 7 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD MAY PY 1997 VL 14 IS 5 BP 1144 EP 1150 DI 10.1364/JOSAA.14.001144 PG 7 WC Optics SC Optics GA WV712 UT WOS:A1997WV71200021 ER PT J AU Nave, G Johansson, S Thorne, AP AF Nave, G Johansson, S Thorne, AP TI Precision vacuum ultraviolet wavelengths of Fe II measured by Fourier-transform and grating spectrometry SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID HOLLOW-CATHODE LAMP; ENERGY-LEVELS; SPECTRUM AB We have measured the wavelengths of 236 Fe II lines between 150 and 200 nm, using Fourier-transform spectrometry. These measurements have been combined with those of 237 lines from 92.7 to 150 nm in high-resolution grating spectra. Ritz wavelengths for all 473 lines have been determined from energy-level values derived from ultraviolet, visible, and infrared Fourier-transform spectrometry and are recommended as wavelength standards with an uncertainty ranging from 0.009 to 0.07 pm (0.005-0.02 cm(-1)). Recent developments in calibrating the spectra from Ar II line standards are discussed. (C) 1997 Optical Society of America. C1 LUND UNIV,DEPT PHYS,S-22362 LUND,SWEDEN. LUND UNIV,LUND OBSERV,LUND,SWEDEN. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. RP Nave, G (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 16 TC 23 Z9 24 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1997 VL 14 IS 5 BP 1035 EP 1042 DI 10.1364/JOSAB.14.001035 PG 8 WC Optics SC Optics GA WY400 UT WOS:A1997WY40000005 ER PT J AU Migdall, A AF Migdall, A TI Polarization directions of noncollinear phase-matched optical parametric downconversion output SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID CONVERSION; PAIRS AB An analysis of the output polarization of a noncollinear type I optical parametric downconversion source is presented. Such a source can be made by pumping a nonlinear crystal with an extraordinary-polarized beam to produce pairs of ordinary-polarized photons. A polarization map of the output light illustrates dramatic variation in the polarization direction at large scattering angles. The effect of this variation in polarization direction is seen on a map of the nonlinear conversion efficiency. The apparent ambiguity in the polarization for the particular case in which one of the outputs propagates along the crystal optic axis is also discussed. (C) 1997 Optical Society of America. RP Migdall, A (reprint author), NIST,OPT TECHNOL DIV,221-B208,GAITHERSBURG,MD 20899, USA. NR 14 TC 19 Z9 20 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1997 VL 14 IS 5 BP 1093 EP 1098 DI 10.1364/JOSAB.14.001093 PG 6 WC Optics SC Optics GA WY400 UT WOS:A1997WY40000013 ER PT J AU Gadzuk, JW AF Gadzuk, JW TI Role of secondary electrons in hot-electron femtochemistry at surfaces using tunnel junctions SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID INDUCED DESORPTION; FIELD-EMISSION; PHOTOCHEMISTRY; SCATTERING; STATE; PHOTODESORPTION; MANIPULATION; MICROSCOPE; RESONANCES; NO/PT(111) AB A theory of resonance-assisted, hot-electron-induced femtochemical processing at surfaces using a tunnel junction device, which has previously been developed in terms of inelastic electron scattering via negative-molecular-ion shape resonances associated with molecules adsorbed on solid surfaces, is extended here to include the effects of secondary electron cascades produced within the device. The potential influence of the secondaries on the proposed control and selectivity of the device is demonstrated and assessed. RP Gadzuk, JW (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 65 TC 14 Z9 14 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1520 EP 1525 DI 10.1116/1.580573 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200074 ER PT J AU Rochford, K Rose, A Wang, CM AF Rochford, K Rose, A Wang, CM TI NIST study investigates retardance uncertainty SO LASER FOCUS WORLD LA English DT Article AB Intercomparison study to determine optical retardance of waveplates and rhombs uncovers limits of high-precision measurements. C1 NATL INST STAND & TECHNOL,STAT ENGN DIV,BOULDER,CO 80303. RP Rochford, K (reprint author), NATL INST STAND & TECHNOL,DIV OPTOELECT,325 BROADWAY,BOULDER,CO 80303, USA. NR 4 TC 8 Z9 8 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD MAY PY 1997 VL 33 IS 5 BP 223 EP 227 PG 5 WC Optics SC Optics GA WZ697 UT WOS:A1997WZ69700049 ER PT J AU Meador, JP Krone, CA Dyer, DW Varanasi, U AF Meador, JP Krone, CA Dyer, DW Varanasi, U TI Toxicity of sediment-associated tributyltin to infaunal invertebrates: Species comparison and the role of organic carbon SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article ID QUALITY CRITERIA; PHASE SEPARATION; PUGET SOUND; BUTYLTINS; AMPHIPODS; MATTER; BIOAVAILABILITY; SPECIATION; ESTUARINE; TISSUE AB Experiments with three species of infaunal invertebrates (a polychaete, Armandia brevis and amphipods, Rhepoxynius abronius and Eohaustorius washingtonianus) with different modes of feeding gave a wide range in toxic response to sediment associated tributyltin (TBT), while exhibiting consistent lethal tissue residues. These studies showed that bioaccumulation and toxicity of sediment-associated TBT were strongly controlled by the organic carbon content of the sediment, which we concluded was primarily due to its influence on interstitial water (IW) concentrations of TBT. Major differences in the response to sediment-associated TBT were found between species, which was attributed to differences in their rates of uptake and elimination of this compound. Predictions for bioaccumulation and toxicity for each species based on these toxicokinetic rates were matched closely by observed values. Based on comparisons of water-only and IW exposures (when water and sediment concentrations of TBT were in equilibrium) and predictions made with toxicokinetic rates, the major route of uptake for each of the species tested appeared to be from dissolved TBT. We determined the mean (sd) organic-carbon normalized sediment-water partition coefficient (K-oc) to be approximately 25 100 (5500) for TOC values ranging from 0.3 to 1.0%, which was five times higher than the reported K-ow. Additionally, we determined the dissolved organic carbon-water partition coefficient (K-doc) to be 1652, which was three fold lower than the K-ow. The results also showed that the K-oc could be influenced by infaunal organisms, presumably by reducing IW concentrations below predicted values, which mises questions about the environmental relevance of sediment bioassays using these organisms and the expected IW concentrations present infield sediments. Published by Elsevier Science Ltd RP Meador, JP (reprint author), NOAA, NATL MARINE FISHERIES SERV, NW FISHERIES SCI CTR, ENVIRONM CONSERVAT DIV, 2725 MONTLAKE BLVD E, SEATTLE, WA 98112 USA. NR 46 TC 42 Z9 46 U1 0 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD MAY PY 1997 VL 43 IS 3 BP 219 EP 241 DI 10.1016/0141-1136(96)00090-6 PG 23 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA VR527 UT WOS:A1997VR52700006 ER PT J AU Queirolo, LE Johnston, RS Zhang, ZK AF Queirolo, LE Johnston, RS Zhang, ZK TI The nature and evolution of cooperative fishing arrangements in extended jurisdiction zones SO MARINE POLICY LA English DT Article DE EEZ; joint-ventures; property rights AB Following the global extension of marine fishery jurisdiction, cooperative fishing arrangements have emerged between coastal nations and distant water fleets. Economic analysis of these arrangements to date has emphasized their bilateral nature and the associated difficulties of influencing and monitoring behavior, including incentive gaps resulting from differing perceptions of the future. When it is recognized that there are many buyers and sellers of ''access'', and that the resources themselves are heterogeneous, the magnitude of such gaps diminishes. We develop a theoretical model and provide empirical evidence supporting the position that a competitive ''international market for access'' is evolving. Published by Elsevier Science Ltd. C1 OREGON STATE UNIV,DEPT AGR & RESOURCE ECON,CORVALLIS,OR 97331. RP Queirolo, LE (reprint author), NOAA,NATL MARINE FISHERIES SERV,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. NR 13 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0308-597X J9 MAR POLICY JI Mar. Pol. PD MAY PY 1997 VL 21 IS 3 BP 255 EP 266 DI 10.1016/S0308-597X(97)00007-9 PG 12 WC Environmental Studies; International Relations SC Environmental Sciences & Ecology; International Relations GA XA238 UT WOS:A1997XA23800005 ER PT J AU Newbury, DE AF Newbury, DE TI Chemical compositional mapping by microbeam analysis at the micrometer scale and finer SO MICROELECTRONICS JOURNAL LA English DT Article ID ELECTRON-PROBE MICROANALYZER AB Spatially-resolved analysis on the micrometer to nanometer spatial scale is possible through the techniques of microbeam analysis. Radiation used includes electrons, ions, photons and neutrons. Both a microprobe and a microscope approach are possible. Techniques generally combine a form of microscopy with an analytical spectrometry. Electron beam techniques are among the most mature and widely applied. Electron probe X-ray micro-analysis under conventional conditions (beam energy 10-30 keV) generally samples on a lateral scale of a micrometer, with sample masses from 1 to 100pg. Strategies for improving the spatial resolution include operation at low overvoltage, operation at low incident beam energy (< 5 keV), and operation on thin foil specimens at high beam energy (> 100 keV). Published by Elsevier Science Ltd. RP Newbury, DE (reprint author), NATL INST STAND & TECHNOL,SURFACE & MICROANAL SCI DIV,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 19 TC 7 Z9 7 U1 0 U2 2 PU ELSEVIER ADVANCED TECHNOLOGY PI OXFORD PA OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0026-2692 J9 MICROELECTR J JI Microelectron. J. PD MAY PY 1997 VL 28 IS 4 BP 489 EP 508 DI 10.1016/S0026-2692(96)00073-0 PG 20 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology SC Engineering; Science & Technology - Other Topics GA WY854 UT WOS:A1997WY85400011 ER PT J AU Ji, M Leetmaa, A AF Ji, M Leetmaa, A TI Impact of data assimilation on ocean initialization and El Nino prediction SO MONTHLY WEATHER REVIEW LA English DT Article ID NATIONAL-METEOROLOGICAL-CENTER; SEA-SURFACE TEMPERATURE; TROPICAL PACIFIC-OCEAN; SOUTHERN OSCILLATION; WIND STRESS; ATMOSPHERE MODEL; PREDICTABILITY; FORECAST; CLIMATE; SYSTEM AB In this study, the authors compare skills of forecasts of tropical Pacific sea surface temperatures From the National Centers for Environmental Prediction (NCEP) coupled general circulation model that were initiated using different sets of ocean initial conditions. These were produced with and without assimilation of observed subsurface upper-ocean temperature data from expendable bathythermographs (XBTs) and from the Tropical Ocean Global Atmosphere-Tropical Atmosphere Ocean (TOGA-TAO) buoys. These experiments show that assimilation of observed subsurface temperature data in the determining of the initial conditions, especially far summer and fall starts, results in significantly improved forecasts for the NCEP coupled model. The assimilation compensates For errors in the forcing fields and inadequate physical parameterizations in the ocean model. Furthermore, additional skill improvements over that provided by XBT assimilation, result from assimilation of subsurface temperature data collected by the TOGA-TAO buoys. This is a consequence of the current predominance of TAO data in the tropical Pacific in recent years. Results suggest that in the presence of erroneous wind forcing and inadequate physical parameterizations in the ocean model ocean data assimilation can improve ocean initialization and thus call improve the skill of the forecasts. However, the need far assimilation can create imbalances between the mean states of the oceanic initial conditions and the coupled model. These imbalances and errors in the coupled model can be significant limiting factors to forecast skill, especially for forecasts initiated in the northern winter. These limiting factors cannot be avoided by using data assimilation and must be corrected by improving the models and the forcing fields. C1 NOAA, NATL WEATHER SERV, NATL CTR ENVIRONM PREDICT, WASHINGTON, DC 20233 USA. NR 40 TC 71 Z9 73 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1997 VL 125 IS 5 BP 742 EP 753 DI 10.1175/1520-0493(1997)125<0742:IODAOO>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX683 UT WOS:A1997WX68300006 ER PT J AU Rosati, A Miyakoda, K Gudgel, R AF Rosati, A Miyakoda, K Gudgel, R TI The impact of ocean initial conditions on ENSO forecasting with a coupled model SO MONTHLY WEATHER REVIEW LA English DT Article ID GENERAL-CIRCULATION MODEL; NINO SOUTHERN OSCILLATION; EL-NINO; DATA ASSIMILATION; ATMOSPHERE MODEL; TROPICAL PACIFIC; SPECTRAL MODEL; WIND STRESS; PREDICTABILITY; SYSTEM AB A coupled atmosphere-ocean GCM (general circulation model) has been developed for climate predictions on seasonal to interannual timescales. The atmosphere model is a global spectral GCM T30L18 and the ocean model is global on a 1 degrees grid. Initial conditions for the atmosphere were obtained from National Meteorological Center (now known as the National Centers for Environmental Prediction) analyses, while those for the ocean came from three ocean data assimilation (DA) systems. One systems a four-dimensional DA scheme that uses conventional SST observations and vertical temperature profiles inserted into the ocean model and is forced from winds from an operational analysis. The other two initialization schemes are based on the coupled model, both nudging the surface temperature toward observed SSTs and one nudging surface winds from an operational analysis. All three systems were run from 1979 to 1988, saving the state of the ocean every month, thus initial conditions may be obtained for any month during this period. The ocean heat content from the three systems was examined, and it was found that a strong lag correlation between Nino-3 SST anomalies and equatorial thermocline displacements crisis. This suggests that, based on subsurface temperature field only, eastern tropical Pacific SST changes are possibly predictable at lead times of a year or more. It is this "memory" that is the physical basis for ENSO predictions. Using the coupled GCM, 13-month forecasts were made for seven January and seven July eases, focusing on ENSO (El Nino-Southern Oscillation) prediction. The forecasts, whose ocean initial conditions contained subsurface thermal data, were successful in predicting the two EI Nino and two La Nina events during the decade, whereas the forecasts that utilized ocean initial conditions from the coupled model that were nudged toward surface wind fields and SST only, failed to predict the events. Despite the coupled model's poor simulation of the annual cycle in the tropical Pacific, the ENSO forecasts from the full DA were remarkably good. RP Rosati, A (reprint author), PRINCETON UNIV, NOAA, GEOPHYS FLUID DYNAM LAB, FORRESTAL CAMPUS, POB 308, PRINCETON, NJ 08542 USA. NR 47 TC 111 Z9 115 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1997 VL 125 IS 5 BP 754 EP 772 DI 10.1175/1520-0493(1997)125<0754:TIOOIC>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX683 UT WOS:A1997WX68300007 ER PT J AU Fischer, M Latif, M Flugel, M Ji, M AF Fischer, M Latif, M Flugel, M Ji, M TI The impact of data assimilation on ENSO simulations and predictions SO MONTHLY WEATHER REVIEW LA English DT Article ID SEA-SURFACE TEMPERATURE; OCEAN-ATMOSPHERE MODEL; TROPICAL PACIFIC; EL-NINO; SYSTEM AB In this study, the impact of oceanic data assimilation on ENSO simulations and predictions is investigated. The authors' main objective is to compare the impact of the assimilation of sea level observations and three-dimensional temperature measurements relative to each other. Three experiments were performed. In a control run the ocean model was forced with observed winds only, and in two assimilation runs three-dimensional temperatures and sea levels were assimilated one by one. The root-mean-square differences between the model solution and observations were computed and heat content anomalies of the upper 275 m compared to each other. Three ensembles of ENSO forecasts were performed additionally to investigate the impact of data assimilation on ENSO predictions. In a control ensemble a hybrid coupled ocean-atmosphere model was initialized with observed winds only, while either three-dimensional temperatures or sea level data were assimilated during the initialization phase in two additional forecast ensembles. The predicted sea surface temperature anomalies were averaged over the eastern equatorial Pacific and compared to observations. Two different objective skill measures were computed to evaluate the impact of data assimilation on ENSO forecasts. The authors' experiments indicate that sea level observations contain useful information and that this information can be inserted successfully into an oceanic general circulation model. It is inferred from the forecast ensembles that the benefit of sea level and temperature assimilation is comparable. However, the positive impact of sea level assimilation could be shown more clearly when the forecasted temperature differences rather than the temperature anomalies themselves were compared with observations. C1 TEXAS A&M UNIV,COLLEGE STN,TX. NATL CTR ENVIRONM PREDICT,WASHINGTON,DC. RP Fischer, M (reprint author), MAX PLANCK INST METEOROL,BUNDESSTR 55,D-20146 HAMBURG,GERMANY. RI Latif, Mojib/C-2428-2016 OI Latif, Mojib/0000-0003-1079-5604 NR 29 TC 28 Z9 33 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1997 VL 125 IS 5 BP 819 EP 829 DI 10.1175/1520-0493(1997)125<0819:TIODAO>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX683 UT WOS:A1997WX68300011 ER PT J AU Langer, SA Glotzer, SC AF Langer, SA Glotzer, SC TI Morphogenesis in nematic liquid crystal polymer materials SO PHYSICA A LA English DT Article; Proceedings Paper CT Proceedings of the International Conference on Pattern Formation in Fluids and Materials CPiP 96 (Collective Phenomena in Physics 96) CY JUN 13-15, 1996 CL UNIV WESTERN ONTARIO, LONDON, CANADA HO UNIV WESTERN ONTARIO ID DYNAMICS AB Materials used in such optical del ices as Bat panel displays often consist of liquid crystal droplets dispersed in a polymer matrix. Because the behavior of the devices depends on the size, shape, and distribution of these droplets, understanding pattern formation in these materials is crucial for optimal processing. The droplets can be formed in a number of ways, all of which combine the processes of phase separation and orientational ordering. The fact that these two processes are coupled makes this problem both theoretically and computationally challenging. C1 NATL INST STAND & TECHNOL,INFORMAT TECHNOL LAB,GAITHERSBURG,MD 20899. RP Langer, SA (reprint author), NATL INST STAND & TECHNOL,CTR THEORET & COMPUTAT MAT SCI,GAITHERSBURG,MD 20899, USA. NR 8 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAY 1 PY 1997 VL 239 IS 1-3 BP 358 EP 362 DI 10.1016/S0378-4371(97)00030-7 PG 5 WC Physics, Multidisciplinary SC Physics GA XE559 UT WOS:A1997XE55900039 ER PT J AU Hobbie, EK AF Hobbie, EK TI Kinetics of size segregation in quasi-two-dimensional nearly-hard-sphere mixtures SO PHYSICAL REVIEW E LA English DT Article ID PHASE-SEPARATION; COLLOIDS; FLUIDS AB Time-resolved phase-contrast microscopy has been used to study the dynamics of size segregation in confined binary colloidal suspensions with a size ratio R-L/R-S approximate to 11 and an approximately hard-sphere potential. The time evolution of the pair-correlation function, the structure factor, the average cluster size, and the total number of large spheres clustered is consistent with entropically driven quasi-two-dimensional ''freezing'' of the minority component. Clustering is evident as a spinodal-like peak in the low-q structure factor. RP Hobbie, EK (reprint author), NATL INST STAND & TECHNOL,DIV POLYMERS,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899, USA. RI Hobbie, Erik/C-8269-2013 NR 19 TC 11 Z9 11 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 MAY PY 1997 VL 55 IS 5 BP 6281 EP 6284 DI 10.1103/PhysRevE.55.6281 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB192 UT WOS:A1997XB19200076 ER PT J AU Fickett, F Chelton, DB AF Fickett, F Chelton, DB TI Bascom W. Birmingham - Obituary SO PHYSICS TODAY LA English DT Item About an Individual RP Fickett, F (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1997 VL 50 IS 5 BP 79 EP 79 DI 10.1063/1.881829 PG 1 WC Physics, Multidisciplinary SC Physics GA WX105 UT WOS:A1997WX10500023 ER PT J AU Wu, WL Wallace, WE vanZanten, JH Bauer, BJ Liu, DW Wong, A AF Wu, WL Wallace, WE vanZanten, JH Bauer, BJ Liu, DW Wong, A TI Diffusion of linear polystyrene into crosslinked polystyrene SO POLYMER LA English DT Article DE diffusion; crosslinked network; concentration profile ID CHAINS; NETWORKS; INTERDIFFUSION; INTERFACE AB The diffusion of linear polystyrene (PS) into its crosslinked counterpart was studied using both neutron reflectivity (NR) and forward recoil scattering (FRES). The penetrant molecular weights were monodisperse and ranged from 10000 to 690000 gmol(-1). The molecular weight between crosslinks was kept at 22000 g mol(-1). The crosslinks were introduced by polymerizing styrene monomer in the presence of divinylbenzene. The FRES results revealed the presence of a high molecular weight cut-off for the linear PS above which diffusion could not proceed. The NR results indicated that even at these high molecular weights a certain amount of diffusion did occur but was confined to the first few hundred Angstroms of the interface. A step function in the polymer concentration profile was found at these high molecular weights as expected for systems showing a limited solubility for the diffusant. The counter diffusion of residual sol from the crosslinked network is used to explain certain features of the diffusion profile. (C) 1997 Elsevier Science Ltd. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP Wu, WL (reprint author), NIST,DIV POLYMERS,BLDG 224 ROOM B320,GAITHERSBURG,MD 20899, USA. NR 18 TC 17 Z9 17 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0032-3861 J9 POLYMER JI Polymer PD MAY PY 1997 VL 38 IS 11 BP 2583 EP 2594 DI 10.1016/S0032-3861(97)85589-9 PG 12 WC Polymer Science SC Polymer Science GA WZ446 UT WOS:A1997WZ44600001 ER PT J AU Holloway, CL Doviak, RJ Cohn, SA Lataitis, RJ VanBaelen, JS AF Holloway, CL Doviak, RJ Cohn, SA Lataitis, RJ VanBaelen, JS TI Cross correlations and cross spectra for spaced antenna wind profilers .2. Algorithms to estimate wind and turbulence SO RADIO SCIENCE LA English DT Article ID RADAR INTERFEROMETER MEASUREMENTS; FULL CORRELATION-ANALYSIS; FREQUENCY-DOMAIN; BOUNDARY-LAYER; VHF RADAR; MODEL; JICAMARCA; FIELD AB In part 1 of this paper we developed analytic relationships linking the cross correlation and cross spectrum of the echoes from a spaced antenna system to the properties of a horizontally isotropic scattering medium (e.g., clear-air refractive index irregularities) and the background flow (e.g., laminar or isotropic turbulent flow). Using these analytic expressions, in the present paper, part 2, we construct algorithms (for both the time domain and frequency domain) for extracting unbiased wind and turbulence estimates. We derive a condition under which one can ignore turbulence when computing winds from the time delay to the peak of the cross-correlation functions. We show profiles of the horizontal wind and turbulence based on these algorithms using data from the unique 33-cm wavelength spaced antenna wind profiler developed by the National Center for Atmospheric Research. C1 NOAA,NATL SEVERE STORMS LAB,NORMAN,OK 73069. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. NOAA,ENVIRONM RES LAB,BOULDER,CO 80303. CNRS,TOULOUSE,FRANCE. RP Holloway, CL (reprint author), NATL TELECOMMUN & INFORMAT ADM,INST TELECOMMUN SCI,325 BROADWAY,BOULDER,CO 80303, USA. NR 37 TC 31 Z9 32 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAY-JUN PY 1997 VL 32 IS 3 BP 967 EP 982 DI 10.1029/96RS03885 PG 16 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA XC931 UT WOS:A1997XC93100010 ER PT J AU Cohn, SA Holloway, CL Oncley, SP Doviak, RJ Lataitis, RJ AF Cohn, SA Holloway, CL Oncley, SP Doviak, RJ Lataitis, RJ TI Validation of a UHF spaced antenna wind profiler for high-resolution boundary layer observations SO RADIO SCIENCE LA English DT Article ID RADAR; NETWORK; SYSTEM; FIELD AB In this paper we apply a spaced antenna technique derived from the recent work of Doviak et al. [1996a] and Holloway et al. [this issue] to wind measurement with a small UHF boundary layer profiler. We discuss the implementation of the technique, averaging and quality control strategies, and some advantages and limitations of spaced antenna methods over conventional Doppler beam swinging wind profilers in the boundary layer. Such advantages include a relaxation of the assumption of a horizontally uniform wind field and the possibility of high temporal resolution wind profiles. In this regard we present velocity measurements derived from this UHF system with time resolution of about 30 s and compare these measurements with in situ sonic anemometer data taken on a 300-m tower. Finally, we present an example of a high-resolution time-height cross section of atmospheric winds. This example, collected in stratiform precipitation, shows the intriguing situation of a wind speed maximum (jet) which closely follows the height of the melting layer over several hours even as this height changes by several hundred meters. C1 NOAA,NATL SEVERE STORMS LAB,NORMAN,OK 73069. NATL TELECOMMUN & INFORMAT ADM,INST TELECOMMUN SCI,BOULDER,CO 80303. NOAA,ENVIRONM RES LABS,BOULDER,CO 80303. RP Cohn, SA (reprint author), NATL CTR ATMOSPHER RES,ATMOSPHER TECHNOL DIV,POB 3000,BOULDER,CO 80307, USA. NR 29 TC 21 Z9 21 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAY-JUN PY 1997 VL 32 IS 3 BP 1279 EP 1296 DI 10.1029/97RS00578 PG 18 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA XC931 UT WOS:A1997XC93100035 ER PT J AU Ratliff, LP Bell, EW Parks, DC Pikin, AI Gillaspy, JD AF Ratliff, LP Bell, EW Parks, DC Pikin, AI Gillaspy, JD TI Continuous highly charged ion beams from the National Institute of Standards and Technology electron-beam ion trap SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB We describe our newly modified beam line and present its performance in conjunction with the National Institute of Standards and Technology electron-beam ion trap. We find that, contrary to previously reported results from similar ion sources, the highest intensity time-averaged ion fluxes are achieved by letting the ions boil out of the trap in a continuous stream rather than periodically trap to produce a pulsed beam. We produced continuous beams of 3.0(6) x 10(6) Xe44+ ions per second and lower flux beams of charge states up to Xe49+. Also, in pulsed mode, we created beams with very high peak flux, over 10(10)Xe(44+) ions per second. C1 DIAMOND SEMICOND GRP,GLOUCESTER,MA 01930. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP Ratliff, LP (reprint author), NIST,ATOM PHYS DIV,GAITHERSBURG,MD 20899, USA. NR 18 TC 28 Z9 29 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1997 VL 68 IS 5 BP 1998 EP 2002 DI 10.1063/1.1148087 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA WZ517 UT WOS:A1997WZ51700012 ER PT J AU Karl, TR Nicholls, N Gregory, J AF Karl, TR Nicholls, N Gregory, J TI The coming climate SO SCIENTIFIC AMERICAN LA English DT Article C1 HADLEY CTR,UK METEOROL OFF,BRACKNELL,BERKS,ENGLAND. AUSTRALIAN BUR,METEOROL RES CTR,MELBOURNE,VIC,AUSTRALIA. RP Karl, TR (reprint author), NOAA,NATL CLIMAT DATA CTR,ROCKVILLE,MD 20852, USA. RI Nicholls, Neville/A-1240-2008; Gregory, Jonathan/J-2939-2016 OI Gregory, Jonathan/0000-0003-1296-8644 NR 6 TC 52 Z9 54 U1 0 U2 6 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD MAY PY 1997 VL 276 IS 5 BP 78 EP 83 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WU977 UT WOS:A1997WU97700024 ER PT J AU Carasso, AS AF Carasso, AS TI Error bounds in nonsmooth image deblurring SO SIAM JOURNAL ON MATHEMATICAL ANALYSIS LA English DT Article DE ill-posed problems; infinitely smoothing operators; image deblurring; SECB restoration; Tikhonov-Miller restoration; nonsmooth images; PET imaging; error bounds ID TOMOGRAPHY AB This paper deals with image deblurring when the unknown original image is not smooth and a priori bounds on its derivatives cannot be prescribed in the inversion algorithm. A significant class of such deblurring problems occurring in medical, industrial, military, astronomical, and environmental applications is shown to be equivalent to backwards-in-time continuation in a generalized diffusion equation that may involve fractional Laplacians. The slow-evolution-from-the-continuation-boundary (SECB) constraint, introduced by the author in [SIAM J. Numer. Anal., 31 (1994), pp. 1535-1557], is applicable to such nonsmooth image deblurring. A new analytical approach based on Fourier analysis provides sharp error estimates for SECB deblurring explicitly in terms of the constants entering the a priori constraints. It also leads to an explicit formula that expresses SECB's improvement over the classical Tikhonov-Miller method. An example from positron emission tomography (PET) imaging is used to illustrate the meaning of the SECB constraint. In this application, use of the SECB constraint reduces the L-2 norm of the Tikhonov-Miller inverse operator by almost a factor of ten. RP Carasso, AS (reprint author), NATL INST STAND & TECHNOL,COMP & APPL MATH LAB,GAITHERSBURG,MD 20899, USA. NR 27 TC 11 Z9 11 U1 1 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0036-1410 J9 SIAM J MATH ANAL JI SIAM J. Math. Anal. PD MAY PY 1997 VL 28 IS 3 BP 656 EP 668 DI 10.1137/S0036141095290215 PG 13 WC Mathematics, Applied SC Mathematics GA WW983 UT WOS:A1997WW98300009 ER PT J AU Harte, SP Vinton, S Lindsay, R Hakansson, L Muryn, CA Thornton, G Dhanak, VR Robinson, AW Binsted, N Norman, D Fischer, DA AF Harte, SP Vinton, S Lindsay, R Hakansson, L Muryn, CA Thornton, G Dhanak, VR Robinson, AW Binsted, N Norman, D Fischer, DA TI Effect of multiple scattering on the S K-edge EXAFS of Ni(110)-c(2x2)-S SO SURFACE SCIENCE LA English DT Letter DE chalcogens; chemisorption; extended X-ray absorption fine structure; low index single crystal surfaces; nickel ID ABSORPTION FINE-STRUCTURE; CURVED-WAVE THEORY; SURFACE-EXAFS; NICKEL SURFACES; METAL SULFIDES; SULFUR; DEPENDENCE; SEXAFS; COVERAGE; XAFS AB We have re-examined the surface geometry of Ni(110)-c(2x2)-S using SEXAFS. Data out to an electron wavevector of 9 Angstrom(-1) are analysed with a new code to assess the influence of multiple scattering. The first-shell S-Ni distance is determined to be 2.20+/-0.02 Angstrom with the next-nearest neighbour distance being 2.29+/-0.02 Angstrom, giving a top-layer Ni expansion of 14+/-3% relative to the bulk. The influence of multiple scattering is sufficiently small not to modify these values. C1 UNIV MANCHESTER,INTERDISCIPLINARY RES CTR SURFACE SCI,MANCHESTER M13 9PL,LANCS,ENGLAND. UNIV MANCHESTER,DEPT CHEM,MANCHESTER M13 9PL,LANCS,ENGLAND. UNIV LIVERPOOL,INTERDISCIPLINARY RES CTR SURFACE SCI,LIVERPOOL L69 3BX,MERSEYSIDE,ENGLAND. SERC,DARESBURY LAB,CCLRC,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. NR 28 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 1 PY 1997 VL 380 IS 1 BP L463 EP L468 DI 10.1016/S0039-6028(96)01590-7 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA WY973 UT WOS:A1997WY97300006 ER PT J AU Wang, CM Lam, CT AF Wang, CM Lam, CT TI A mixed-effects model for the analysis of circular measurements SO TECHNOMETRICS LA English DT Article DE circle fitting; coordinate measuring machine; tolerance region; variance components ID STATISTICAL BEHAVIOR; STRUCTURAL MODEL; ESTIMATORS; TOLERANCE; INTERVALS; CIRCLES AB This article presents a statistical model for measurements collected on the circumference of circular features. The proposed model takes into consideration the center location variability of different machined parts. Maximum likelihood estimators are derived for both the within- and between-parts variations as well as for the geometric parameters. Statistical procedures' are developed to assess the performance of the manufacturing process in producing parts that conform to design specifications and to keep track of the trend of the manufacturing process over time. An example for a transmission gear carrier is presented to illustrate the use of the results. RP Wang, CM (reprint author), NATL INST STAND & TECHNOL,STAT ENGN DIV,325 BROADWAY,BOULDER,CO 80303, USA. NR 20 TC 7 Z9 12 U1 0 U2 1 PU AMER STATISTICAL ASSOC PI ALEXANDRIA PA 1429 DUKE ST, ALEXANDRIA, VA 22314 SN 0040-1706 J9 TECHNOMETRICS JI Technometrics PD MAY PY 1997 VL 39 IS 2 BP 119 EP 126 DI 10.2307/1270900 PG 8 WC Statistics & Probability SC Mathematics GA WV217 UT WOS:A1997WV21700001 ER PT J AU Doucette, GJ Logan, MM Ramsdell, JS VanDolah, FM AF Doucette, GJ Logan, MM Ramsdell, JS VanDolah, FM TI Development and preliminary validation of a microtiter plate-based receptor binding assay for paralytic shellfish poisoning toxins SO TOXICON LA English DT Article ID SAXITOXIN BINDING; SYNAPTOSOMES; ALEXANDRIUM AB More than 20 countries have either established or proposed regulatory limits for one or more of the paralytic shellfish poisoning (PSP) toxins as they occur in seafood products. PSP toxin levels are generally estimated using the standard AOAC mouse bioassay, yet because of various limitations of this method [e.g. high variability (+/-20%), low sensitivity, limited sample throughput and use of live animals], there remains a need for alternative testing protocols. A sensitive and selective, high capacity assay was developed for the PSP toxins which exploits the highly specific interaction of these toxins with their biological receptor (i.e. voltage-dependent sodium channel) and is thus based on functional activity. This receptor binding assay provides a radioactive endpoint, and is performed in a microtiter filter plate format with results determined by standard liquid scintillation counting within 24 hr. The K-i for the assay is 3.66 +/- 0.86 nM saxitoxin, with a limit of detection of c. 5 ng saxitoxin/ml in a sample extract, Good quantitative agreement of the assay with both mouse bioassay and high-performance liquid chromatographic analysis of crude extracts of contaminated shellfish, as well as PSP toxin-producing algae, was observed, Our findings indicate that the receptor binding assay has a strong predictive value for toxicity determined by mouse bioassay, and that this approach warrants consideration as a rapid, reliable and cost-effective alternative to live animal testing for detection and estimation of PSP-related toxicity in seafood and toxic algae. RP Doucette, GJ (reprint author), NATL MARINE FISHERIES SERV,CHARLESTON LAB,MARINE BIOTOXINS PROGRAM,219 FT JOHNSON RD,CHARLESTON,SC 29412, USA. RI Doucette, Gregory/M-3283-2013 NR 27 TC 88 Z9 91 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0041-0101 J9 TOXICON JI Toxicon PD MAY PY 1997 VL 35 IS 5 BP 625 EP 636 DI 10.1016/S0041-0101(96)00189-4 PG 12 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA XE623 UT WOS:A1997XE62300001 PM 9203287 ER PT J AU Gessner, BD Bell, P Doucette, GJ Moczydlowski, E Poli, MA VanDolah, F Hall, S AF Gessner, BD Bell, P Doucette, GJ Moczydlowski, E Poli, MA VanDolah, F Hall, S TI Hypertension and identification of toxin in human urine and serum following a cluster of mussel-associated paralytic shellfish poisoning outbreaks SO TOXICON LA English DT Article ID SAXITOXIN-BINDING PROTEIN; SODIUM-CHANNELS; MUSCLE; TETRODOTOXIN; BULLFROG; RAT; SAXIPHILIN; CHEMISTRY; CHILE AB Following four outbreaks of paralytic shellfish poisoning on Kodiak Island, Alaska, during 1994, medical records of ill persons were reviewed and interviews were conducted, Urine and serum specimens were analyzed at three independent laboratories using four different saxitoxin binding assays, High-performance liquid chromatography was used to determine the presence of specific toxin congeners, Among 11 ill persons, three required mechanical ventilation and one died, Mean peak systolic and diastolic blood pressure measurements were 172 (range 128-247) and 102 (range 78-165) mmHg, respectively, and blood pressure measurements corresponded with ingested toxin dose, All four different laboratory methodologies detected toxin in serum at 2.8-47 nM during acute illness and toxin in urine at 65-372 nM after acute symptom resolution. The composition of specific paralytic shellfish poisons differed between mussels and human biological specimens, suggesting that human metabolism of toxins had occurred. The results of this study indicate that saxitoxin analogues may cause severe hypertension. In addition, we demonstrate that saxitoxins can be detected in human biological specimens, that nanomolar serum toxin levels may cause serious illness and that human metabolism of toxin may occur. Clearance of paralytic shellfish poisons from serum was evident within 24 hr and urine was identified as a major route of toxin excretion in humans. (C) 1997 Elsevier Science Ltd. C1 YALE UNIV, SCH MED, DEPT PHARMACOL, NEW HAVEN, CT 06520 USA. YALE UNIV, SCH MED, DEPT CELLULAR & MOL PHYSIOL, NEW HAVEN, CT 06520 USA. US DEPT COMMERCE, NOAA, SE FISHERIES SCI CTR, NATL MARINE FISHERIES SERV, CHARLESTON, SC 29422 USA. USA, MED RES INST INFECT DIS, FT DETRICK, MD 21702 USA. US FDA, WASHINGTON, DC 20204 USA. RP Gessner, BD (reprint author), ALASKA DIV PUBL HLTH, 1231 GAMBELL ST, 2ND FLOOR, ANCHORAGE, AK 99501 USA. RI Moczydlowski, Edward/A-9304-2009; Moczydlowski, Edward/D-1734-2013; Doucette, Gregory/M-3283-2013 NR 35 TC 61 Z9 65 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0041-0101 J9 TOXICON JI Toxicon PD MAY PY 1997 VL 35 IS 5 BP 711 EP 722 DI 10.1016/S0041-0101(96)00154-7 PG 12 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA XE623 UT WOS:A1997XE62300010 PM 9203296 ER PT J AU Savina, MR Lykke, KR AF Savina, MR Lykke, KR TI Chemical imaging of surfaces with laser desorption mass spectrometry SO TRAC-TRENDS IN ANALYTICAL CHEMISTRY LA English DT Article ID IONIZATION AB Mass spectrometric imaging of surfaces can reveal features not evident in micrographs. The use of two lasers, one to desorb atoms and molecules and a second to ionize them in the gas phase, produces a reasonably steady ion yield as the desorption spot is rastered across a surface. When combined with a time-of-flight mass analyzer, the result is a simple instrument capable of molecular imaging with micron resolution. C1 NIST,DIV OPT TECHNOL,GAITHERSBURG,MD 20899. RP Savina, MR (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 31 TC 12 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-9936 J9 TRAC-TREND ANAL CHEM JI Trac-Trends Anal. Chem. PD MAY PY 1997 VL 16 IS 5 BP 242 EP 252 DI 10.1016/S0165-9936(97)00028-9 PG 11 WC Chemistry, Analytical SC Chemistry GA XJ329 UT WOS:A1997XJ32900016 ER PT J AU Waldman, JR Richards, RA Schill, WB Wirgin, I Fabrizio, MC AF Waldman, JR Richards, RA Schill, WB Wirgin, I Fabrizio, MC TI An empirical comparison of stock identification techniques applied to striped bass SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID MITOCHONDRIAL-DNA POLYMORPHISMS; CHESAPEAKE BAY; HUDSON RIVER; RELATIVE CONTRIBUTIONS; FISHERY COMPOSITION; MORONE-SAXATILIS; ATLANTIC COAST; DISCRIMINATION; CLASSIFICATION; ONCORHYNCHUS AB Managers of migratory striped bass stocks that mix along the Atlantic coast of the USA require periodic estimates of the relative contributions of the individual stocks to coastal mixed-stock fisheries; however, to date, a standard approach has not been adopted. We compared the performances of alternative stock identification approaches, using samples taken from the same sets of fish. Reference (known) samples were collected from three Atlantic coast spawning systems: the Hudson River, Chesapeake Bay, and the Roanoke River. Striped bass of mixed-stock origin were collected from eastern Long Island, New York, and were used as test (unknown) samples. The approaches applied were discriminant analysis of morphometric data and of meristic data, logistic regression analysis of combined meristic and morphometric data, discriminant analysis of scale-shape features, discriminant analysis of immunoassay data, and mixed-stock analysis of mitochondrial DNA (mtDNA) data. Overall correct classification rates of reference samples ranged from 94% to 66% when just the Hudson and Chesapeake stocks were considered and were comparable when the Chesapeake and Roanoke stocks were grouped as the ''southern'' stock. When all three stocks were treated independently, correct classification rates ranged from 82% to 49%. Despite the moderate range in correct classification rates, bias due to misallocation was relatively low for all methods, suggesting that resulting stock composition estimates should be fairly accurate. However, relative contribution estimates for the mixed-stock sample varied widely (e.g., from 81% to 47% for the Hudson River stock, when only the Hudson River and Chesapeake Bay stocks were considered). Discrepancies may be related to the reliance by all of these approaches (except mtDNA) on phenotypic features. Our results support future use of either a morphometrics-based approach (among the phenotypic methods) or a genotypic approach based on mtDNA analysis. We further recommend a conservative strategy of reliance on a single approach in tracking changes in relative contributions of striped bass stocks to coastal fisheries. C1 NATL MARINE FISHERIES SERV,NE FISHERIES SCI CTR,WOODS HOLE,MA 02543. US GEOL SURVEY,LEETOWN SCI CTR,NATL FISH HLTH RES LAB,KEARNEYSVILLE,WV 25430. NYU,INST ENVIRONM MED,MED CTR,TUXEDO PK,NY 10987. US GEOL SURVEY,BIOL RESOURCES DIV,GREAT LAKES SCI CTR,ANN ARBOR,MI 48105. RP Waldman, JR (reprint author), HUDSON RIVER FDN SCI & ENVIRONM RES,40 W 20TH ST,9TH FLOOR,NEW YORK,NY 10011, USA. OI Fabrizio, Mary/0000-0002-6115-5490; Schill, William/0000-0002-9217-984X NR 50 TC 36 Z9 41 U1 0 U2 5 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 1997 VL 126 IS 3 BP 369 EP 385 DI 10.1577/1548-8659(1997)126<0369:AECOSI>2.3.CO;2 PG 17 WC Fisheries SC Fisheries GA XN047 UT WOS:A1997XN04700003 ER PT J AU Grosse, DJ Scholz, PM Hirshfield, MF Meaburn, GM Fletcher, M AF Grosse, DJ Scholz, PM Hirshfield, MF Meaburn, GM Fletcher, M TI Fisheries and pollution: A conference overview SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Editorial Material C1 NOAA,COASTAL SERV CTR,CHARLESTON,SC 29405. CTR MARINE CONSERVAT,WASHINGTON,DC 20036. NATL MARINE FISHERIES SERV,CHARLESTON LAB,CHARLESTON,SC 29412. MARYLAND BIOTECHNOL INST,CTR MARINE BIOTECHNOL,BALTIMORE,MD 21202. RP Grosse, DJ (reprint author), TERRAQUA ENVIRONM SCI & POLICY,LLC,3754 JENIFER ST NW,WASHINGTON,DC 20015, USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 1997 VL 126 IS 3 BP 504 EP 505 PG 2 WC Fisheries SC Fisheries GA XN047 UT WOS:A1997XN04700014 ER PT J AU Boreman, J AF Boreman, J TI Methods for comparing the impacts of pollution and fishing on fish populations SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article; Proceedings Paper CT Conference on Fisheries and Pollution - Population-Level Effects of Marine Contamination CY OCT 12-13, 1995 CL BALTIMORE, MD SP NOAA, Coastal Serv Ctr, Natl Marine Fisheries Serv, Charleston Lab, Ctr Marine Conservat, Maryland Biotechnol Inst, Ctr Marine Biotechnol, Rifkin & Assoc Inc, TerrAqua Environm Sci & Policy, LLC ID STRIPED BASS; MORTALITY; STOCK AB Until recently, human-induced perturbations other than fishing have received little attention in the stock assessment literature. Beginning in the late 1960s, environmental legislation in the United States has directed attention toward assessing the mortality of fish and other living aquatic resources caused by observed (or anticipated) changes in water quality or other habitat features that are related to ongoing (or proposed) human activity. Scientists are being requested not only to devise means to estimate the extent of aquatic impacts related to the causes, but also to devise means to reduce or avoid them. In this paper I review methods that can be used for comparing the population-level effects of mortality in fish populations induced by pollution (and sources with similar effects) to mortality induced by fishing. I also review the types of data needed to use the methods, limitations of the methods, and examples of method applications. Methods reviewed are the equivalent adult, production forgone, reproductive potential (eggs per recruit and spawning stock biomass per recruit), and individual-based. All of the methods reviewed share several common limitations, the foremost being inherent difficulties in estimating survival rates for early life stages of fish. Despite their shortcomings, the methods have been and continue to be useful tools for fishery management. RP Boreman, J (reprint author), UNIV MASSACHUSETTS,INST ENVIRONM,COOPERAT MARINE EDUC & RES PROGRAM,NOAA,AMHERST,MA 01003, USA. NR 38 TC 10 Z9 11 U1 0 U2 7 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 1997 VL 126 IS 3 BP 506 EP 513 DI 10.1577/1548-8659(1997)126<0506:MFCTIO>2.3.CO;2 PG 8 WC Fisheries SC Fisheries GA XN047 UT WOS:A1997XN04700015 ER PT J AU Landahl, JT Johnson, LL Stein, JE Collier, TK Varanasi, U AF Landahl, JT Johnson, LL Stein, JE Collier, TK Varanasi, U TI Approaches for determining effects of pollution on fish populations of Puget Sound SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article; Proceedings Paper CT Conference on Fisheries and Pollution - Population-Level Effects of Marine Contamination CY OCT 12-13, 1995 CL BALTIMORE, MD SP NOAA, Coastal Serv Ctr, Natl Marine Fisheries Serv, Charleston Lab, Ctr Marine Conservat, Maryland Biotechnol Inst, Ctr Marine Biotechnol, Rifkin & Assoc Inc, TerrAqua Environm Sci & Policy, LLC ID SOLE PAROPHRYS-VETULUS; SCOPHTHALMUS-MAXIMUS L; LIMANDA-LIMANDA L; ENGLISH SOLE; REPRODUCTIVE SUCCESS; HEPATIC-LESIONS; CHEMICAL CONTAMINANTS; MORTALITY-RATES; PLEURONECTES-VETULUS; EUROPEAN WATERS AB Puget Sound is a large marine and estuarine ecosystem in Washington State that serves as the habitat for a number of recreationally and commercially important species of groundfish and Pacific salmon Onchorhynchus spp. Over the past several decades, the human population of the Puget Sound drainage basin has increased substantially, resulting in increased habitat degradation and chemical pollution. There is now a body of evidence showing that groundfish and salmon in Puget Sound are experiencing a range of biological effects from chemical contaminant exposure, including impairment of several stages in the reproductive process, increased susceptibility to pathogens resulting from altered immune competence, and development of toxicopathic diseases. Preliminary studies suggest the potential for reduced survival of fish from urban areas of Puget Sound resulting from increased infectious and idiopathic diseases. The question that now must be addressed is whether contaminant-related reductions in reproductive and survival rates are sufficient to affect fish abundance in Puget Sound. fn the current study, the potential impact of contaminant-related mortality and reproductive impairment on the population growth rate of English sole Pleuronectes vetulus was examined by simulation modeling. An initial Leslie matrix population model was constructed for investigation of contaminant effects. The adult mortality rate for English sole in Puget Sound was estimated from recent historical data. Age-specific fecundity was determined from previously collected English sole ovary samples. Existing data on the effects of contaminants on reproduction, including impaired gonadal development, reduced spawning ability, and decreased egg and larval viability, were incorporated into the fecundity component of the model. The influence of density-dependent population regulation on model results was also examined. Results suggest that declines in the fecundity component of the model, like those observed in field studies of fish from contaminated sites such as the Duwamish Waterway and Eagle Harbor, could substantially decrease the population growth rate (r) if density dependence is weak or moderate. Estimated declines in r are comparable in magnitude to those associated with typical levels of commercial fishing pressure. However, a compensation for loss of recruits due to contaminant effects is observed if strong density-dependent population regulation is assumed. RP Landahl, JT (reprint author), NOAA, NATL MARINE FISHERIES SERV, NW FISHERIES SCI CTR, SEATTLE, WA 98112 USA. NR 74 TC 14 Z9 15 U1 3 U2 16 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 1997 VL 126 IS 3 BP 519 EP 535 DI 10.1577/1548-8659(1997)126<0519:AFDEOP>2.3.CO;2 PG 17 WC Fisheries SC Fisheries GA XN047 UT WOS:A1997XN04700017 ER PT J AU Hsu, SM Shen, MC Ruff, AW AF Hsu, SM Shen, MC Ruff, AW TI Wear prediction for metals SO TRIBOLOGY INTERNATIONAL LA English DT Article DE friction; metals; wear; wear mechanisms; wear models ID MAPS; TEMPERATURES; SURFACES; CONTACT; MODEL AB In spite of the large number of wear models found in the literature, no model can predict metal wear a priori based only on materials property data and contact information. The complexity of wear and the large number of parameters affecting the outcome are the primary reasons for this situation. This paper summarizes the current understanding of wear modelling for metals. Several recent approaches such as wear mapping and wear transition diagrams have suggested some future possible directions for improvement. Some success has been achieved in describing severe wear of steels under unlubricated conditions using thermomechanical approaches. However, modelling of mild wear remains problematic, especially under lubricated conditions. In mild wear, asperity contact events dominate the wear processes. A single asperity collision simulation apparatus has been used to study asperity-asperity contact phenomena. Shear strain and strain accumulation were found to be the dominant underlying causes for wear. It is proposed that future research in wear prediction for metals incorporate the following aspects: wear mapping, temperature, shear strain response, boundary lubricating film strength, and surface roughness. (C) 1997 Elsevier Science Ltd. RP Hsu, SM (reprint author), NIST,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 27 TC 53 Z9 56 U1 2 U2 10 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0301-679X J9 TRIBOL INT JI Tribol. Int. PD MAY PY 1997 VL 30 IS 5 BP 377 EP 383 DI 10.1016/S0301-679X(96)00067-9 PG 7 WC Engineering, Mechanical SC Engineering GA WR315 UT WOS:A1997WR31500007 ER PT J AU Stivers, JT Harris, TK Mildvan, AS AF Stivers, JT Harris, TK Mildvan, AS TI Vaccinia DNA topoisomerase I: Evidence supporting a free rotation mechanism for DNA supercoil relaxation SO BIOCHEMISTRY LA English DT Article ID CLEAVAGE; BINDING; REQUIREMENTS; STEP AB The Vaccinia type I topoisomerase catalyzes site-specific DNA strand cleavage and religation by forming a transient phosphotyrosyl linkage between the DNA and Tyr-274, resulting in the release of DNA supercoils. For type I topoisomerases, two mechanisms have been proposed for supercoil release: (1) a coupled mechanism termed strand passage, in which a single supercoil is removed per cleavage/religation cycle, resulting in multiple topoisomer intermediates and late product formation, or (2) an uncoupled mechanism termed free rotation, where multiple supercoils are removed per cleavage/religation cycle, resulting in few intermediates and early product formation. To determine the mechanism, single-turnover experiments were done with supercoiled plasmid DNA under conditions in which the topoisomerase cleaves predominantly at a single site per DNA molecule. The concentrations of supercoiled substrate, intermediate topoisomers, and relaxed product vs time were measured by fluorescence imaging, and the rate constants for their interconversion were determined by kinetic simulation. Few intermediates and early product formation were observed. From these data, the rate constants for cleavage (0.3 s(-1)), religation (4 s(-1)), and the cleavage equilibrium constant on the enzyme (0.075) at 22 degrees C are in reasonable agreement with those obtained with small oligonucleotide substrates, while the rotation rate of the cleaved DNA strand is fast (similar to 20 rotations/s). Thus, the average number of supercoils removed for each cleavage event greatly exceeds unity (Delta n = 5) and depends on kinetic competition between religation and supercoil release, establishing a free rotation mechanism. This free rotation mechanism for a type I topoisomerase differs from the strand passage mechanism proposed for the type II enzymes. C1 NIST,ROCKVILLE,MD 20850. JOHNS HOPKINS UNIV,SCH MED,DEPT BIOL CHEM,BALTIMORE,MD 21205. RP Stivers, JT (reprint author), UNIV MARYLAND,MARYLAND BIOTECHNOL INST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850, USA. FU NIDDK NIH HHS [DK28616]; NIGMS NIH HHS [GM17514] NR 30 TC 80 Z9 81 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD APR 29 PY 1997 VL 36 IS 17 BP 5212 EP 5222 DI 10.1021/bi962880t PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA WW560 UT WOS:A1997WW56000016 PM 9136883 ER PT J AU Poole, PH Glotzer, SC Coniglio, A Jan, N AF Poole, PH Glotzer, SC Coniglio, A Jan, N TI Emergence of fast local dynamics on cooling toward the ising spin glass transition SO PHYSICAL REVIEW LETTERS LA English DT Article ID MULTIDIMENSIONAL NMR; CRITICAL-BEHAVIOR; O-TERPHENYL; RELAXATION; POLYSTYRENE; MOLECULES; FIELD AB We present a detailed Monte Carlo evaluation of the equilibrium distribution of local spin-flip rates and local energies in the paramagnetic phase of the d = 2 and d = 3 +/- J Ising spin glass. Both quantities are spatially heterogeneous, and we find that the shapes of the distributions change dramatically with decreasing temperature, In particular as temperature decreases we find that for an increasing fraction of spins the local spin-flip rate and local energy increase as the glass transition is approached. C1 NIST,CTR THEORET & COMPUTAT MAT SCI,GAITHERSBURG,MD 20899. UNIV NAPLES,DIPARTIMENTO SCI FIS,I-80125 NAPLES,ITALY. ST FRANCIS XAVIER UNIV,DEPT PHYS,ANTIGONISH,NS B2G 2W5,CANADA. RP Poole, PH (reprint author), UNIV WESTERN ONTARIO,DEPT APPL MATH,LONDON,ON N6A 5B7,CANADA. RI Poole, Peter/C-7943-2009 OI Poole, Peter/0000-0001-5985-0585 NR 27 TC 28 Z9 28 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 28 PY 1997 VL 78 IS 17 BP 3394 EP 3397 DI 10.1103/PhysRevLett.78.3394 PG 4 WC Physics, Multidisciplinary SC Physics GA WW399 UT WOS:A1997WW39900042 ER PT J AU Portmann, RW Solomon, S Fishman, J Olson, JR Kiehl, JT Briegleb, B AF Portmann, RW Solomon, S Fishman, J Olson, JR Kiehl, JT Briegleb, B TI Radiative forcing of the Earth's climate system due to tropical tropospheric ozone production SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AEROSOLS; MODEL AB The radiative forcing of the Earth's climate system due to tropical tropospheric ozone is estimated using ozonesonde profiles and maps of the tropospheric ozone column derived from satellite data. The forcing is estimated using several different techniques in order to place bounds on its likely magnitude and to elucidate the role of biomass burning in producing the observed forcing. The results suggest that a widespread radiative forcing of at least 0.5 to 1 W m(-2) exists over large areas in the tropics for much of the year. This radiative forcing is comparable in magnitude, but opposite in sign, to estimates of the aerosol forcing from tropical biomass burning. However, the burning contribution to ozone forcing is present over a larger geographic area than the aerosol forcing. The majority of the burning and thus these radiative forcings have likely been present only in the past century. These enhancements in tropical ozone are also estimated to be responsible for a radiative forcing of between 0.1 and 0.4 W m(-2) when globally averaged. Comparison of these regional and global forcings due to tropical ozone changes to the estimates of forcing due to carbon dioxide and other trace gas increases since preindustrial times (about 2.45 W m(-2)) suggests that the effects of tropical ozone changes could be significant for evaluation of both regional and global anthropogenic forcing of climate. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP NOAA, AERON LAB, R-E-AL8, 325 S BROADWAY, BOULDER, CO 80303 USA. RI Portmann, Robert/C-4903-2009 OI Portmann, Robert/0000-0002-0279-6087 NR 35 TC 41 Z9 44 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 27 PY 1997 VL 102 IS D8 BP 9409 EP 9417 DI 10.1029/96JD04007 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WW559 UT WOS:A1997WW55900009 ER PT J AU Angell, JK AF Angell, JK TI Stratospheric warming due to Agung, El Chichon, and Pinatubo taking into account the quasi-biennial oscillation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID VOLCANIC-ERUPTION; TEMPERATURE-CHANGE; AEROSOLS; MEXICO; OZONE AB Radiosonde data are used to estimate the impact on stratospheric temperature of Agung, El Chichon, and Pinatubo volcanic eruptions, taking into account the quasibiennial oscillation (QBO). This is done by comparing the temperature variations following the three eruptions with the average quasi-biennial variation in temperature obtained by applying the superposed epoch method to the 13 QBO cycles (centered on Singapore 50 mbar east wind maxima) between 1958 and 1996 which do not include these three eruptions. Confidence estimates are based on the 2-standard deviation value of the 13 comparisons. Shown are estimates of the volcanic impact and approximate 95% confidence intervals in 300-100 and 100-50 mbar layers of polar, temperate, subtropical, and equatorial zones (and the globe as a whole), as well as in north subtropical and equatorial zones at pressure surfaces of 50, 30, 20, and 10 mbar. Based on this procedure, and ignoring other possible influences on stratospheric temperature, all three eruptions warmed the tropical low stratosphere by nearly 2 degrees C, with the largest warming 3 degrees C at 50 mbar in the equatorial zone following Agung and Pinatubo. Above 50 mbar, the volcanic warming usually decreases with height in the tropics, an exception being the 2 degrees C warming of the 10 mbar surface in the north subtropics following El Chichon. While the volcanic warming is most frequently a maximum 2 seasons after the eruption, the warming duration can be 2 years. In the polar zones there is evidence of cooling of stratospheric 300-100 and 100-50 mbar layers following the eruptions. Comparisons are made with other volcanic warming estimates. RP NOAA, AIR RESOURCES LAB, 1315 E W HIGHWAY, SILVER SPRING, MD 20910 USA. NR 35 TC 45 Z9 45 U1 4 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 27 PY 1997 VL 102 IS D8 BP 9479 EP 9485 DI 10.1029/96JD03588 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WW559 UT WOS:A1997WW55900014 ER PT J AU Berry, RJ Ehlers, CJ Burgess, DR Zachariah, MR Marshall, P AF Berry, RJ Ehlers, CJ Burgess, DR Zachariah, MR Marshall, P TI A computational study of the reactions of atomic hydrogen with fluoromethanes: Kinetics and product channels SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ELECTRON-SPIN-RESONANCE; TRANSITION-STATE THEORY; ACTIVATION-ENERGIES; ABSTRACTION; ENTHALPIES; EXCHANGE; METHANE; CF3BR; CH3; OH AB Transition states for the H-abstraction, F-abstraction and substitution pathways of the reaction of H with fluoromethanes were characterized at the HF and MP2(FU) levels of theory with the 6-31G(d) basis set. The reaction barrier heights for these pathways were obtained from single point energy calculations using the Gaussian-2 and BAC-MP4 methods. These results were employed to calculate rate constants via transition state theory. The computed rate constants are in good accord with available experimental data, and are discussed in the context of the differing flame suppression chemistries of CH3F, CH2F2, CHF3 and CF4. C1 NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. UNIV N TEXAS,DEPT CHEM,DENTON,TX 76203. RP Berry, RJ (reprint author), USAF,WRIGHT LAB,CTR COMPUTAT MODELING NONSTRUCT MAT,MAT DIRECTORATE,WRIGHT PATTERSON AFB,OH 45433, USA. NR 35 TC 34 Z9 34 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 25 PY 1997 VL 269 IS 1-2 BP 107 EP 116 DI 10.1016/S0009-2614(97)00248-0 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WV113 UT WOS:A1997WV11300017 ER PT J AU Williams, GP AF Williams, GP TI Planetary vortices and Jupiter's vertical structure SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID OUTER PLANETS; DYNAMICS; ATMOSPHERES AB Measurements of the vertical structure of Jupiter's circulation have recently been made near the equator by the Galileo spacecraft probe. In other regions, planetary vortices exist selectively; for a limited range of generic (exponential) vertical forms and can be used to probe the atmospheric structure theoretically. A study of vortex genesis with a three-dimensional numerical model produces reasonably realistic simulations of the Great Red Spot for both the generic and galilean forms, provided that Jupiter's winds do not extend much beyond a 500 km depth. However, the actual depth of the winds remains uncertain. RP Williams, GP (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,FORRESTAL CAMPUS,US ROUTE 1,POB 308,PRINCETON,NJ 08542, USA. NR 19 TC 18 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 1997 VL 102 IS E4 BP 9303 EP 9308 DI 10.1029/97JE00520 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WX323 UT WOS:A1997WX32300024 ER PT J AU McAdoo, D Laxon, S AF McAdoo, D Laxon, S TI Antarctic tectonics: Constraints from an ERS-1 satellite marine gravity field SO SCIENCE LA English DT Article ID PLATE MOTIONS; WEDDELL SEA; GEOSAT DATA; PACIFIC; OCEAN; GONDWANALAND; EVOLUTION; HISTORY; MODEL; FLOOR AB A high-resolution gravity field of poorly charted and ice-covered ocean near West Antarctica, from the Ross Sea east to the Weddell Sea, has been derived with the use of satellite altimetry, including ERS-1 geodetic phase, wave-form data. This gravity field reveals regional tectonic fabric, such as gravity lineations, which are the expression of fracture zones left by early (65 to 83 million years ago) Pacific-Antarctic sea-floor spreading that separated the Campbell Plateau and New Zealand continent from West Antarctica. These lineations constrain plate motion history and confirm the hypothesis that Antarctica behaved as two distinct plates, separated from each other by an extensional Bellingshausen plate boundary active in the Amundsen Sea before about 61 million years ago. C1 UCL, MULLARD SPACE SCI LAB, DEPT SPACE & CLIMATE PHYS, DORKING RH5 6NT, SURREY, ENGLAND. RP McAdoo, D (reprint author), NATL OCEAN SERV, GEOSCI LAB, NATL OCEAN & ATMOSPHER ADM, SILVER SPRING, MD 20910 USA. RI Laxon, Seymour/C-1644-2008; McAdoo, Dave/F-5612-2010 OI McAdoo, Dave/0000-0002-7533-5564 NR 37 TC 66 Z9 68 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 APR 25 PY 1997 VL 276 IS 5312 BP 556 EP 560 DI 10.1126/science.276.5312.556 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WV721 UT WOS:A1997WV72100036 ER PT J AU Miyano, KE Woicik, JC Robins, LH Bouldin, CE Wickenden, DK AF Miyano, KE Woicik, JC Robins, LH Bouldin, CE Wickenden, DK TI Extended x-ray absorption fine structure study of AlxGa(1-x)N films SO APPLIED PHYSICS LETTERS LA English DT Article ID ALXGA1-XN AB Extended x-ray absorption fine structure above the Ga-K edge has been used to study the local structure of AlxGal-xN films grown by metal organic chemical vapor deposition. With increasing Al content, x, the Ga-N bond length decreases, but much less than the average bond length. On the other hand, the x dependence of the Ga-Ga and Ga-Al distances does follow the variation of the average cation-cation distance. We conclude that bond angle distortions accommodate the differences between the Ga-N and Al-N bond lengths. (C) 1997 American Institute of Physics. C1 CUNY BROOKLYN COLL,BROOKLYN,NY 11210. NIST,GAITHERSBURG,MD 20899. JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. RP Miyano, KE (reprint author), CUNY,CTR ADV TECHNOL ULTRAFAST PHOTON MAT & APPLICAT,NEW YORK,NY 10031, USA. NR 10 TC 41 Z9 42 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 21 PY 1997 VL 70 IS 16 BP 2108 EP 2110 DI 10.1063/1.118963 PG 3 WC Physics, Applied SC Physics GA WU601 UT WOS:A1997WU60100015 ER PT J AU Proffitt, MH Langford, AO AF Proffitt, MH Langford, AO TI Ground-based differential absorption lidar system for day or night measurements of ozone throughout the free troposphere SO APPLIED OPTICS LA English DT Article DE lidar; differential absorption lidar; ozone; troposphere ID STRATOSPHERIC OZONE; ARCTIC STRATOSPHERE; FORMALDEHYDE CH2O; DIAL MEASUREMENTS; PROFILES; UV; PHOTOMETER; LASER AB The National Oceanic and Atmospheric Administration Aeronomy Laboratory's rapid tunable daylight differential absorption lidar system for monitoring ozone throughout the free troposphere is described. The system components are optimized to provide continuously and rapidly profiles of ozone, day or night, with a vertical resolution of 1 km and an absolute accuracy of +/-10% to the tropopause under clear sky conditions. Routine observations of ozone with frequent error assessments are made by scanning wavelengths between 286 and 292 nm. (C) 1997 Optical Society of America. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Proffitt, MH (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Langford, Andrew/D-2323-2009 OI Langford, Andrew/0000-0002-2932-7061 NR 66 TC 34 Z9 38 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 1997 VL 36 IS 12 BP 2568 EP 2585 DI 10.1364/AO.36.002568 PG 18 WC Optics SC Optics GA WU839 UT WOS:A1997WU83900024 PM 18253247 ER PT J AU Weatherhead, EC Tiao, GC Reinsel, GC Frederick, JE DeLuisi, JJ Choi, DS Tam, WK AF Weatherhead, EC Tiao, GC Reinsel, GC Frederick, JE DeLuisi, JJ Choi, DS Tam, WK TI Analysis of long-term behavior of ultraviolet radiation measured by Robertson-Berger meters at 14 sites in the United States SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SUNLIGHT; TRENDS AB Surface ultraviolet (UV) radiation measurements from the Robertson-Berl (RB) meter network and existing documentation of these data were examined to determine long-term variations of UV. RB meter data from 14 sites in the United States were analyzed for trends over the period 1974-1991. A more in-depth analysis of the RB meter data, including the use of supporting geophysical data, was carried out for four of the locations. Results based on analysis of data from the 14 sites show a significant negative trend of the order of -6% per decade overall, reasonably consistent with annual trends obtained by Scotto et al. [1988] using similar data for the period 1974-1985. However, when allowance is made for mean level shifts in the data for several of the stations around 1979, which may be due to calibration anti other instrument-related problems, the resulting overall trend is found to be of the order of +2% per decade and not statistically significant. An additional trend analysis using only RB meter data since 1979 at the 14 sites is also performed and leads to overall trend results similar to those from the analysis which allows for mean level shifts in the data. The more detailed analysis of data from four of the stations for the period 1979-1991 is performed to investigate the extent to which the trend behavior in the RB meter measurements call be explained by the behavior of other geophysical quantities such as cloudiness and total ozone. In particular, radiative transfer model-based calculations of ultraviolet irradiance based on satellite data from the total ozone mapping spectrometer are compared with the RB meter measurements to help explain their behavior. Generally, inconsistencies are found between the trend behavior in RB meter measurements and radiative transfer calculations, with the RB data showing substantial downward movement relative to the calculations for three of the four sites. Significant evidence exists to indicate that problems with the network render the existing RB meter measurements unreliable for long-term trend detection. Different reasonable treatments of the data result in dramatically different trend results. Without further information, the data, by themselves, do not allow for definitive trend analysis results. C1 UNIV CHICAGO, GRAD SCH BUSINESS, CHICAGO, IL 60637 USA. UNIV WISCONSIN, DEPT STAT, MADISON, WI 53706 USA. UNIV CHICAGO, DEPT GEOPHYS SCI, CHICAGO, IL 60637 USA. NOAA, ENVIRONM RES LAB, BOULDER, CO 80303 USA. UNIV CHICAGO, DEPT STAT, CHICAGO, IL 60637 USA. RP Weatherhead, EC (reprint author), UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, CAMPUS BOX 449, BOULDER, CO 80309 USA. RI Weatherhead, Elizabeth/I-7091-2015 OI Weatherhead, Elizabeth/0000-0002-9252-4228 NR 14 TC 52 Z9 52 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 1997 VL 102 IS D7 BP 8737 EP 8754 DI 10.1029/96JD03590 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX558 UT WOS:A1997WX55800003 ER PT J AU Harris, JM Oltmans, SJ AF Harris, JM Oltmans, SJ TI Variations in tropospheric ozone related to transport at American Samoa SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC METHANE; FLOW PATTERNS; CLIMATOLOGY; SURFACE; RECORD AB Ten years of isentropic trajectories were summarized using cluster analysis to describe flow patterns for American Samoa. The trajectories were then paired with surface ozone data to determine the dependence of surface ozone on transport. The two main transport regimes affecting surface ozone are trade wind transport, where trajectories show flow bringing ozone from the east in the tropical marine boundary layer, and midlatitude transport, where trajectories show strong westerly flow at higher elevations of southern midlatitudes, followed by descent with anticyclonic curvature. These two transport regimes yield ozone from distinctly different origins, having different mixing ratios. The seasonally changing frequency of transport type is shown to be partly responsible for the seasonal cycle and changes in variability of Samoa surface ozone. On average, 45% of winter ozone variation can be explained by differences in transport type. This strong relationship was absent, however, during 1991, probably because of UV blocking by aerosols from the eruption of Mount Pinatubo. Reduced total column ozone during winter 1992 may have contributed to this season having the lowest surface ozone levels of the study period. RP Harris, JM (reprint author), NOAA, CLIMATE MONITORING & DIAGNOST LAB, 325 BROADWAY, BOULDER, CO 80303 USA. NR 25 TC 21 Z9 22 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 20 PY 1997 VL 102 IS D7 BP 8781 EP 8791 DI 10.1029/97JD00238 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX558 UT WOS:A1997WX55800006 ER PT J AU Hurst, DF Bakwin, PS Myers, RC Elkins, JW AF Hurst, DF Bakwin, PS Myers, RC Elkins, JW TI Behavior of trace gas mixing ratios on a very tall tower in North Carolina SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CARBON-MONOXIDE; NITROUS-OXIDE; METHANE; TRENDS; OZONE; TROPOSPHERE; LIFETIMES; DECREASE; PROFILES; DIOXIDE AB We present a 15-month record of mixing ratios of CO, CH4, N2O, and eight halogenated gases (CCl3F, CCl2F2, CCl2FCClF2, CH3CCl3, CCl4, CHCl3, C2Cl4, and SF6) at a rural site in eastern North Carolina. The data result from hourly gas chromatographic analyses of air sampled at three heights on a 610-m-tall telecommunications tower during November 1994 through January 1996. At night, most of these gases were more abundant near the ground (51 m) than aloft (496 m) because of the buildup of local and regional surface emissions in the shallow nocturnal stable layer. The abundance and variability of trace gases at this continental site were generally higher than those at similar latitude remote locations. Mixing ratios of most gases were well correlated in polluted air masses occasionally advected to the tower. Frequent, strong enhancements in CHCl3 at the lower sampling level(s) indicate a local point source(s) of this gas that is not associated with combustion. Temporal trends of regional background mixing ratios at this continental site are, for the most part, in good agreement with recent trends of remote background mixing ratios in the northern hemisphere. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Hurst, DF (reprint author), NOAA, CLIMATE MONITORING & DIAGNOST LAB, 325 BROADWAY, BOULDER, CO 80303 USA. RI Hurst, Dale/D-1554-2016 OI Hurst, Dale/0000-0002-6315-2322 NR 39 TC 29 Z9 32 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 APR 20 PY 1997 VL 102 IS D7 BP 8825 EP 8835 DI 10.1029/97JD00130 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX558 UT WOS:A1997WX55800010 ER PT J AU McPeters, RD Labow, GJ Johnson, BJ AF McPeters, RD Labow, GJ Johnson, BJ TI A satellite-derived ozone climatology for balloonsonde estimation of total column ozone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERIC OZONE; NIMBUS-7 SBUV; TRENDS AB The standard technique for computing total column ozone from a balloonsonde measurement includes an extrapolation of the measured ozone profile to altitudes above the balloon burst altitude. This total column calculation can be improved by using a monthly average ozone climatology based on ozone profile measurements from the solar backscattered ultraviolet instrument on the Nimbus 7 satellite. For each month and 10 degrees latitude zone we provide the column ozone above 30 distinct pressure levels in the middle and upper atmosphere (from 1 through 30 mbar) that can be added to the measured balloon profile. Use of this climatology reduces the uncertainty in the column ozone estimate when the sonde data are compared with simultaneous Dobson observations at Boulder and at Mauna Loa. C1 NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. HUGHES STX CORP, GREENBELT, MD 20770 USA. RP McPeters, RD (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 916, GREENBELT, MD 20771 USA. RI McPeters, Richard/G-4955-2013 OI McPeters, Richard/0000-0002-8926-8462 NR 16 TC 60 Z9 62 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 1997 VL 102 IS D7 BP 8875 EP 8885 DI 10.1029/96JD02977 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX558 UT WOS:A1997WX55800016 ER PT J AU Wennberg, PO Brault, JW Hanisco, TF Salawitch, RJ Mount, GH AF Wennberg, PO Brault, JW Hanisco, TF Salawitch, RJ Mount, GH TI The atmospheric column abundance of IO: Implications for stratospheric ozone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ABSORPTION CROSS-SECTIONS; CHLORINE RADICALS; DIURNAL-VARIATION; MID-LATITUDE; KINETICS; BRO; SPECTROSCOPY; PHOTOLYSIS; IODINE; CHEMISTRY AB Absorption attributable to atmospheric IO is observed in high-resolution, high air mass solar spectra taken at the National Solar Observatory, Kitt Peak, Arizona, in March 1995. These observations, together with cross sections measured in the laboratory for the IO {A(2) Pi(3/2)<--X-2 Pi(3/2) (2,0)} rotationally resolved electronic transition, are consistent with a total stratospheric iodine mixing ratio of 0.2 (+0.3 -0.2) parts per trillion by volume. This result, combined with recent laboratory measurements of the rate of the reactions of IO with other halogen species, suggests that iodine chemistry is not responsible for the reductions observed in lower stratospheric ozone during the last several decades. C1 UNIV COLORADO, DEPT CHEM & BIOCHEM, BOULDER, CO 80309 USA. NOAA, AERON LAB, BOULDER, CO 80307 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP Wennberg, PO (reprint author), HARVARD UNIV, DEPT CHEM & BIOL CHEM, 12 OXFORD ST, CAMBRIDGE, MA 02138 USA. RI Salawitch, Ross/B-4605-2009; Wennberg, Paul/A-5460-2012 OI Salawitch, Ross/0000-0001-8597-5832; NR 49 TC 40 Z9 40 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 20 PY 1997 VL 102 IS D7 BP 8887 EP 8898 DI 10.1029/96JD03712 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX558 UT WOS:A1997WX55800017 ER PT J AU Hofmann, DJ Oltmans, SJ Harris, JM Johnson, BJ Lathrop, JA AF Hofmann, DJ Oltmans, SJ Harris, JM Johnson, BJ Lathrop, JA TI Ten years of ozonesonde measurements at the south pole: Implications for recovery of springtime Antarctic ozone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID QUASI-BIENNIAL OSCILLATION; PINATUBO VOLCANIC AEROSOL; INTERANNUAL VARIABILITY; STRATOSPHERIC CLOUDS; EQUATORIAL QBO; EL-CHICHON; HOLE; DEPLETION; TRANSPORT; SEPTEMBER AB Ten years of ozonesonde data at the south pole are used to investigate trends and search for indicators that can be used to detect Antarctic ozone recovery in the future. These data indicate that there have been no systematic winter temperature trends at altitudes of 7-25 km and thus no expected changes in stratospheric cloud particle surface area, which would affect heterogeneous chemistry. Springtime ozone depletion has been very severe since about 1992, with near-total loss of ozone in the 14- to 18-km region, but has lessened somewhat in 1994 and 1995, probably because of the decay of the sulfate aerosol from the Mount Pinatubo eruption which was present at 10-16 km. Sulfate aerosol particles from the Pinatubo eruption resulted in new ozone depletion in 1992 and 1993 in the 10- to 12-km region where it is too warm for polar stratospheric clouds (PSCs) to form. The volcanic aerosol also augmented depletion related to PSCs at 12-16 km. Although ozone depletion was not as severe in 1995 as in 1993, the depleted region remained intact longer than ever, with record low values throughout December in 1995. Since about 1992, a pseudo-equilibrium seems to have been reached in which springtime ozone depletion, as measured by the total column or the ozone in the 12- to 20-km main stratospheric cloud region, has remained relatively constant. Independent of volcanic aerosol, ozone depletion has extended into the upper altitudes at 22-24 km since about 1992. There is some indication that ozone depletion has also worsened at the bottom of the depletion region at 12-14 km. Extensions of the ozone hole in the vertical dimension are believed to be the result of increases in man-made halogens and not due to changes in particle surface area or dynamics. A quasi-biennial component in the ozone destruction rate in September, especially above 18 km, is believed to be related to variations in the transport of halogen-bearing molecules to the polar region. A number of indicators for recovery of the ozone hole have been identified. They include an end to springtime ozone depletion at 22-24 km, a 12- to 20-km mid-September column ozone loss rate of less than about 3 Dobson Units (DU) per day, and a 12- to 20-km ozone column value of more than about 70 DU on September 15. It is estimated that if the Montreal protocol and its amendments, banning and/or limiting substances that deplete the ozone layer, is adhered to, recovery of the Antarctic ozone hole may be conclusively detected from the aforementioned changes in the vertical profile of ozone as early as the year 2008. Future volcanic eruptions would affect ozone at 10-16 km, making detection more difficult, but indicators such as depletion in the 22- to 24-km region will be immune to these effects. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Hofmann, DJ (reprint author), NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. NR 32 TC 70 Z9 71 U1 2 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 APR 20 PY 1997 VL 102 IS D7 BP 8931 EP 8943 DI 10.1029/96JD03749 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX558 UT WOS:A1997WX55800020 ER PT J AU Zhou, ST Rottman, GJ Miller, AJ AF Zhou, ST Rottman, GJ Miller, AJ TI Stratospheric ozone response to short- and intermediate-term variations of solar UV flux SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LONG-TERM; MIDDLE ATMOSPHERE; VARIABILITY; MODEL; PERIODICITY AB On the basis of three years (October 1991 through September 1994) of UARS SOLSTICE (solar stellar irradiance comparison experiments) and MLS (microwave limb sounder) data, correlations between tropical ozone and spectral solar UV flux have been studied. In addition to the 27-day period of solar rotation, this new result shows a relatively weak UV-ozone correlation at periods of 60-80 days in the upper stratosphere. The 60-80 day correlation coefficient (similar to 0.5) is somewhat smaller than the 27-day correlation (similar to 0.7). For the 60-80 day periodicity the overall phase lag of ozone is about 2 weeks throughout the 1-10 mbar layer, but the phase relation differs each year. This suggests that dynamical effects could be influencing the 60-80 day ozone variation. Although the 60-80 day solar variation is much smaller than the 27-day variation, the ozone response to these solar variations is about as strong. Further investigation of the 60-80 day variation using alternate data sets for different time periods would be desirable. C1 NATL CTR ATMOSPHER RES, HIGH ALTITUDE OBSERV, BOULDER, CO 80307 USA. RP Zhou, ST (reprint author), NOAA, NATL CTR ENVIRONM PREDICT, W NMC53, 200 AUTH RD, WASHINGTON, DC 20233 USA. NR 20 TC 21 Z9 21 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 20 PY 1997 VL 102 IS D7 BP 9003 EP 9011 DI 10.1029/96JD03383 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WX558 UT WOS:A1997WX55800027 ER PT J AU Edgar, JH Smith, DT Eddy, CR Carosella, CA Sartwell, BD AF Edgar, JH Smith, DT Eddy, CR Carosella, CA Sartwell, BD TI c-Boron aluminum nitride alloys prepared by ion-beam assisted deposition SO THIN SOLID FILMS LA English DT Article DE boron nitride; aluminium nitride; ion-beam-assisted deposition ID FILMS; STRESS AB The structure, mechanical, and chemical properties of boron-aluminum nitride thin films prepared by ion-beam-assisted deposition (IBAD) are reported. The ratio of N to Al + B as determined by Auger electron spectroscopy was consistently 1.0 in all films. The c-lattice constant of the alloy decreased linearly up to approximately 10% BN, suggesting the formation of a single-phase AlN-wurtzite-BN alloy. The hardness of the films was between 20 and 25 GPa, as measured by nanoindentation, and did not change significantly with the amount of boron present. The etch rate in warm phosphoric acid of an alloy containing 9% BN was an order of magnitude lower than that of pure AlN. C1 NIST,DIV CERAM,GAITHERSBURG,MD 20899. USN,RES LAB,WASHINGTON,DC 20375. RP Edgar, JH (reprint author), KANSAS STATE UNIV,DEPT CHEM ENGN,DURLAND HALL,MANHATTAN,KS 66506, USA. RI Smith, Douglas/I-4403-2016 OI Smith, Douglas/0000-0002-9358-3449 NR 22 TC 21 Z9 22 U1 0 U2 10 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 20 PY 1997 VL 298 IS 1-2 BP 33 EP 38 DI 10.1016/S0040-6090(96)08884-0 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA XH324 UT WOS:A1997XH32400005 ER PT J AU Harvey, AH AF Harvey, AH TI On the suitability of the virial equation for modeling the solubility of solids in supercritical fluids SO FLUID PHASE EQUILIBRIA LA English DT Article DE molecular simulation; solid-fluid equilibria; solubility; supercritical fluids; virial equation ID COMPRESSED GASES; STATE; MIXTURES AB Five model systems, the van der Waals fluid, the Soave-Redlich-Kwong fluid, the Peng-Robinson fluid, the hard-sphere fluid, and the square-well fluid, are used to examine the performance of the truncated virial expansion in describing the fugacity of a solute at infinite dilution in a solvent. It is demonstrated that the virial fugacity results deteriorate at significantly lower densities as the solute becomes larger. This has consequences for attempts to describe the solubility of solids in supercritical fluids, where the virial expansion, truncated after the third virial coefficient, has been considered as a modeling option. The results of this work suggest that, for the densities and solute-to-solvent size ratios commonly encountered in supercritical extraction, the truncated virial expansion should not be expected to describe correctly the solute fugacity, and therefore any success it has in fitting solubility data should be viewed with caution. (C) 1997 Elsevier Science B.V. RP Harvey, AH (reprint author), NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,PHYS & CHEM PROPERTIES DIV,325 BROADWAY,BOULDER,CO 80303, USA. NR 26 TC 12 Z9 12 U1 1 U2 2 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 APR 15 PY 1997 VL 130 IS 1-2 BP 87 EP 100 DI 10.1016/S0378-3812(96)03228-1 PG 14 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA XB292 UT WOS:A1997XB29200007 ER PT J AU Bates, TS Quinn, PK AF Bates, TS Quinn, PK TI Dimethylsulfide (DMS) in the equatorial Pacific Ocean (1982 to 1996): Evidence of a climate feedback? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NORTHEAST PACIFIC; SULFUR; ATMOSPHERE; PHYTOPLANKTON; SULFIDE AB Oceanic dimethylsulfide (DMS) is the major natural source of sulfur to the atmosphere. The equatorial Pacific Ocean is a region of relatively high DMS emissions that persist throughout the year. Measurements from 11 cruises between 1982 and 1996 show that the mean surface seawater DMS concentration in this region (15 degrees N to 15 degrees S) is relatively constant both seasonally and interannually (2.7 +/- 0.7 nM). The large interannual variations in oceanic and atmospheric properties associated with El Nino-Southern Oscillation (ENSO) events appear to have little effect on the concentration of DMS in surface ocean waters. RP Bates, TS (reprint author), NOAA, PACIFIC MARINE ENVIRONM LAB, 7600 SAND POINT WAY NE, SEATTLE, WA 98115 USA. RI Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 24 TC 35 Z9 35 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 1997 VL 24 IS 8 BP 861 EP 864 DI 10.1029/97GL00784 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WU965 UT WOS:A1997WU96500009 ER PT J AU Slavin, JA Fairfield, DH Lepping, RP Szabo, A Reiner, MJ Kaiser, M Owen, CJ Phan, T Lin, R Kokubun, S Mukai, T Yamamoto, T Singer, HJ Romanov, SA Buechner, J Iyemori, T Rostoker, G AF Slavin, JA Fairfield, DH Lepping, RP Szabo, A Reiner, MJ Kaiser, M Owen, CJ Phan, T Lin, R Kokubun, S Mukai, T Yamamoto, T Singer, HJ Romanov, SA Buechner, J Iyemori, T Rostoker, G TI WIND, GEOTAIL, and GOES 9 observations of magnetic field dipolarization and bursty bulk flows in the near-tail SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLASMA SHEET; SIGNATURES AB The WIND, GEOTAIL, and GOES 9 spacecraft were all in the nightside magnetosphere and Interball was in the solar wind when a substorm began at similar to 07:25 UT on April 18, 1996. WIND and GEOTAIL were located at downstream distances of X = -12 to -14 R-c. The separation between these spacecraft was similar to 10 R-c in the Y direction and less than similar to 1 R-c in Z. While the northward field component at GOES 9 began to increase immediately, little or no dipolarization was observed at WIND and GEOTAIL until a series of very rapid B-z increases were observed similar to 25-30 min later. About similar to 1-2 min prior to each dipolarization event at WIND and GEOTAIL an earthward flow burst with peak speeds of 100-500 km/s was initiated. The duration of these bursty bulk flows were 1-7 min. These unique observations are interpreted as strong evidence for the existence of spatially localized, but sometimes temporally overlapping flow bursts in the near-tail during substorm expansion phase which result, cumulatively, in sufficient earthward magnetic flux transport to produce the well known dipolarization at geosynchronous orbit. C1 UNIV LONDON QUEEN MARY & WESTFIELD COLL, ASTRON UNIT, LONDON E1 4N3, ENGLAND. UNIV CALIF BERKELEY, SPACE SCI LAB, BERKELEY, CA 94720 USA. NAGOYA UNIV, SOLAR TERR ENVIRONM LAB, TOYOKAWA 442, JAPAN. INST SPACE & ASTRONAUT SCI, KANAGAWA 229, JAPAN. NOAA, SPACE ENVIRONM CTR, BOULDER, CO 80303 USA. RUSSIAN ACAD SCI, SPACE RES INST, MOSCOW 117810, RUSSIA. MAX PLANCK INST AERON, D-37191 KATLENBURG DUHM, GERMANY. UNIV ALBERTA, DEPT PHYS, EDMONTON, AB T6G 2J1, CANADA. KYOTO UNIV, DATA ANAL CTR GEOMAGNETISM & SPACE MAGNETISM, KYOTO, JAPAN. RP Slavin, JA (reprint author), NASA, GODDARD SPACE FLIGHT CTR, EXTRATERR PHYS LAB, GREENBELT, MD 20771 USA. RI Owen, Christopher/C-2999-2008; Buechner, Joerg/B-1213-2009; Slavin, James/H-3170-2012 OI Owen, Christopher/0000-0002-5982-4667; Slavin, James/0000-0002-9206-724X NR 12 TC 42 Z9 44 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 15 PY 1997 VL 24 IS 8 BP 971 EP 974 DI 10.1029/97GL00542 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WU965 UT WOS:A1997WU96500037 ER PT J AU Pulkkinen, TI Baker, DN Turner, NE Singer, HJ Frank, LA Sigwarth, JB Scudder, J Anderson, R Kokubun, S Nakamura, R Mukai, T Blake, JB Russell, CT Kawano, H Mozer, F Slavin, JA AF Pulkkinen, TI Baker, DN Turner, NE Singer, HJ Frank, LA Sigwarth, JB Scudder, J Anderson, R Kokubun, S Nakamura, R Mukai, T Blake, JB Russell, CT Kawano, H Mozer, F Slavin, JA TI Solar wind magnetosphere coupling during an isolated substorm event: A multispacecraft ISTP study SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOCATION AB Multispacecraft data from the upstream solar wind, polar cusp, and inner magnetotail are used to show that the polar ionosphere responds within a few minutes to a southward IMF turning, whereas the inner tail signatures are visible within ten min from the southward turning. Comparison of two subsequent substorm onsets, one during southward and the other during northward IMF, demonstrates the dependence of the expansion phase characteristics on the external driving conditions. Both onsets are shown to have initiated in the midtail, with signatures in the inner tail and auroral oval following a few minutes later. C1 UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242. AEROSP CORP,LOS ANGELES,CA 90009. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. NAGOYA UNIV,SOLAR TERR ENVIRONM LAB,TOYOKAWA,AICHI 442,JAPAN. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. NOAA,SPACE ENVIRONM CTR,BOULDER,CO 80303. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. FINNISH METEOROL INST,FIN-00101 HELSINKI,FINLAND. RP Pulkkinen, TI (reprint author), UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,1234 INNOVAT DR,BOULDER,CO 80303, USA. RI Slavin, James/H-3170-2012; Nakamura, Rumi/I-7712-2013; Pulkkinen, Tuija/D-8403-2012; OI Slavin, James/0000-0002-9206-724X; Nakamura, Rumi/0000-0002-2620-9211; Pulkkinen, Tuija/0000-0002-6317-381X; Turner, Niescja/0000-0002-3280-4260; Russell, Christopher/0000-0003-1639-8298 NR 6 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 15 PY 1997 VL 24 IS 8 BP 983 EP 986 DI 10.1029/97GL00816 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WU965 UT WOS:A1997WU96500040 ER PT J AU Lummerzheim, D Brittnacher, M Evans, D Germany, GA Parks, GK Rees, MH Spann, JF AF Lummerzheim, D Brittnacher, M Evans, D Germany, GA Parks, GK Rees, MH Spann, JF TI High time resolution study of the hemispheric power carried by energetic electrons into the ionosphere during the May 19/20, 1996 auroral activity SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID THERMOSPHERE; ATMOSPHERE AB The ultraviolet imager (UVI) on board the POLAR satellite offers the opportunity to obtain high time resolution global auroral images. The spectral discrimination of the imager is sufficient to separate the auroral far ultraviolet emissions from the scattered sunlight, even when the entire auroral Bone is sunlit. The energy flux of the precipitating electrons is derived from the surface brightness through the LBH-long filter. Global images which have the dayglow removed are spatially integrated to yield the total rate of energy input into the northern hemisphere. This parameter, the hemispheric power, has found much application in ionospheric modeling. It can also be derived from electron spectra measured along the track of the NOAA/TIROS satellites that are combined with average empirical auroral precipitation patterns. We show that the hemispheric power derived from the two-dimensional images represents a substantial improvement in the temporal variability of this parameter. We present an example for the period of 19/20 May 1996 by comparing the hemispheric power derived from NOAA/TIROS measurements with those derived from the UVI images. C1 UNIV WASHINGTON,GEOPHYS PROGRAM,SEATTLE,WA 98195. NOAA,SPACE ENVIRONM CTR,BOULDER,CO 80303. UNIV ALABAMA,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. UNIV SOUTHAMPTON,DEPT PHYS,SOUTHAMPTON SO17 1BJ,HANTS,ENGLAND. RP Lummerzheim, D (reprint author), UNIV ALASKA,INST GEOPHYS,FAIRBANKS,AK 99775, USA. NR 11 TC 50 Z9 50 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 15 PY 1997 VL 24 IS 8 BP 987 EP 990 DI 10.1029/96GL03828 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WU965 UT WOS:A1997WU96500041 ER PT J AU Borchers, JA Gehring, PM Majkrzak, CF Zeltser, AM Smith, N Ankner, JF AF Borchers, JA Gehring, PM Majkrzak, CF Zeltser, AM Smith, N Ankner, JF TI Dependence of the interlayer coupling on anneal temperature in Ni-Fe/Cu evaporated multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID GIANT MAGNETORESISTANCE; THIN-FILMS AB Resistivity and magnetization studies of [Ni83Fe17(27 Angstrom)\Cu(37 Angstrom)](10) multilayers, grown by electron-beam evaporation, reveal that the magnetoresistance (Delta R/R) increases from <0.3% to 4.4% following a heat treatment at 325 degrees C. Polarized neutron reflectivity measurements on annealed samples show that the interlayer coupling changes from ferromagnetic to antiferromagnetic, confirming the conclusions of the bulk studies. Data for the 300 and 325 degrees C annealed samples in small fields show a magnetic peak at half-order that is absent for the as-deposited and 275 degrees C annealed multilayers. Some of the Ni-Fe spins in the annealed multilayers are thus ordered in large (>100 mu m) in-plane domains aligned antiparallel across the Cu layers. An increase in the magnetic scattering at low angles indicates that some of the remaining Ni-Fe moments are randomly oriented from one layer to the next. (C) 1997 American Institute of Physics. C1 EASTMAN KODAK CO,SAN DIEGO LABS,SAN DIEGO,CA 92121. UNIV MISSOURI,RES REACTOR FACIL,COLUMBIA,MO 65211. RP Borchers, JA (reprint author), NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899, USA. OI Ankner, John/0000-0002-6737-5718; Gehring, Peter/0000-0002-9236-2046 NR 13 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3771 EP 3773 DI 10.1063/1.364745 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600011 ER PT J AU Hyman, RA Stiles, MD Tang, LH Zangwill, A AF Hyman, RA Stiles, MD Tang, LH Zangwill, A TI Coercivity of ultrathin films with in-plane magnetization SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID ANISOTROPIES AB We report numerical and analytic results for a model of coercivity and magnetization reversal in an array of square monolayer-height magnetic islands on a monolayer of magnetic material with in-plane magnetization. Reversal nucleates at step edges where local two-fold anisotropy is present in addition to the intrinsic four-fold anisotropy of the (001) flat surface of a cubic crystal. Simple analytic formulas for the coercive field are derived that agree well with numerical simulations. (C) 1997 American Institute of Physics. C1 NIST,ELECTRON PHYS GRP,GAITHERSBURG,MD 20899. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. RP Hyman, RA (reprint author), GEORGIA INST TECHNOL,SCH PHYS,ATLANTA,GA 30332, USA. RI Stiles, Mark/K-2426-2012 OI Stiles, Mark/0000-0001-8238-4156 NR 9 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3911 EP 3913 DI 10.1063/1.365068 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600066 ER PT J AU Chopra, HD Hockey, BJ Chen, PJ McMichael, RD Egelhoff, WF AF Chopra, HD Hockey, BJ Chen, PJ McMichael, RD Egelhoff, WF TI Nanostructuue, interfaces, and magnetic properties in giant magnetoresistive NiO-Co-Cu-based spin valves SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID MULTILAYERS AB Giant magnetoresistive NiO-Co-Cu-based top and symmetric spin valves were studied with emphasis on the role of oxygen partial pressure, p(O-2), in affecting the magnetic pinning of Co by NiO. Results show a correlation between the underlying nanostructure and pinning strength as a function of p(O-2). High-resolution transmission electron microscopy show that at progressively higher oxygen partial pressures, NiO-Co interface becomes crystallographically disordered, in part, due to the oxidation of Co layer on which NiO is deposited; an amorphous film is formed at the interface. An optimum p(O-2) interval for the deposition of NiO is identified (similar to 1 X 10(-5)-3.0 X 10(-5) Torr), in which a sharp and crystallographically well-defined NiO-Co interface can exist. Finally, a simple model suggest that defect structures at the NiO-Co interface may play an important role in the magnetization reversal of a NiO-pinned Co layer in an applied field. (C) 1997 American Institute of Physics. C1 UNIV MARYLAND,DEPT MAT & NUCL ENGN,COLLEGE PK,MD 20742. DARTMOUTH COLL,THAYER SCH ENGN,HANOVER,NH 03755. RP Chopra, HD (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. RI McMichael, Robert/J-8688-2012; OI McMichael, Robert/0000-0002-1372-664X NR 13 TC 23 Z9 23 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4017 EP 4019 DI 10.1063/1.365273 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600106 ER PT J AU Seyoum, HM Melamud, M WongNg, W Bennett, LH Swartzendruber, LJ Cook, L Brown, HJ AF Seyoum, HM Melamud, M WongNg, W Bennett, LH Swartzendruber, LJ Cook, L Brown, HJ TI Effect of barium cuprate on high temperature superconductors SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID GRANULAR SUPERCONDUCTORS; REENTRANT SUPERCONDUCTIVITY; CHARGING ENERGY; METAL-FILMS; TRANSITION AB BaCuO2 has a pronounced effect on the magnetization data of high-T-c superconductors. By subtracting the estimated magnetic contribution of BaCuO2 present in the superconducting samples, the susceptibility is seen to be purely diamagnetic. (C) 1997 American Institute of Physics. C1 NUCL RES CTR NEGEV,IL-84190 BEER SHEVA,ISRAEL. NIST,GAITHERSBURG,MD 20899. GEORGE WASHINGTON UNIV,ASHBURN,VA 22011. RP Seyoum, HM (reprint author), UNIV DIST COLUMBIA,DEPT PHYS,4200 CONNECTICUT AVE NW,WASHINGTON,DC 20008, USA. NR 16 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4244 EP 4246 DI 10.1063/1.365135 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600190 ER PT J AU Swartzendruber, LJ Hicho, GE Chopra, HD Leigh, SD Adam, G Tsory, E AF Swartzendruber, LJ Hicho, GE Chopra, HD Leigh, SD Adam, G Tsory, E TI Effect of plastic strain on magnetic and mechanical properties of ultralow carbon sheet steel SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB We have investigated how plastic deformation changes the yield stress and the magnetic properties of an ultralow carbon sheet steel. Plastic strains up to 10% nearly doubled the yield stress from 150 to 290 MPa (22-42 ksi), and the coercive field from 0.17 to 0.31 kA/m (2.1-3.9 Oe). The effects on other magnetic properties, such as the Barkhausen signal and permeability, were also determined. It was found that a single magnetic parameter could be related to the yield stress with residual standard deviations as low as 1 MPa (0.2 ksi). Observations using a high-resolution interference-contrast colloid technique revealed a fine intragrain magnetic domain structure with the walls more effectively pinned in the 10% strained material. (C) 1997 American Institute of physics. C1 NUCL RES CTR NEGEV,IL-84190 BEER SHEVA,ISRAEL. RP Swartzendruber, LJ (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 6 TC 28 Z9 28 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4263 EP 4265 DI 10.1063/1.364796 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600197 ER PT J AU Unguris, J Celotta, RJ Davies, A Pierce, DT Stroscio, JA AF Unguris, J Celotta, RJ Davies, A Pierce, DT Stroscio, JA TI Effect of interfacial roughness on exchange coupling SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,ELECTRON PHYS GRP,GAITHERSBURG,MD 20899. RI Unguris, John/J-3989-2014 NR 0 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4342 EP 4342 DI 10.1063/1.364762 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600225 ER PT J AU Crawford, TM Rogers, CT Silva, TJ Kim, YK AF Crawford, TM Rogers, CT Silva, TJ Kim, YK TI Nonlinear optical investigations of magnetic heterostructures SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID GIANT MAGNETORESISTANCE; 2ND-HARMONIC GENERATION; MULTILAYERS AB We report second-harmonic magneto-optic Kerr effect investigations of magnetic heterostructures. The heterostructures studied are multilayers of Si/Al2O3/Cu(50 nm)/Ni81Fe19(x), Si/Al2O3/Cu(50 nm)/Co(2 nm)/Ni81Fe19(x), and Si/Al2O3Cu(50 nm)/Ni81Fe19(x)/Cu(5 nm), where x ranges from 1 to 30 nm. For films thinner than the optical penetration depth, the transverse second-harmonic Kerr effect experimentally separates and distinctly identifies each of these multilayered structures. We find that the addition of the 2 nm Co layer between Cu and Ni81Fe19 increases the magnetic signature in the second-harmonic intensity by more than a factor of two. This increase correlates with the observed magnetoresistance increase in spin valves with the addition of Co. For films thicker than the penetration depth, the structures with air-exposed Ni81Fe19 are identical, but they differ significantly from Ni81Fe19 films capped with Cu. We used spectroscopic ellipsometry to determine the linear optical properties of each film in the structure. Modeling of both Cu(50 nm)/Ni81Fe19 and Cu(50 nm)/Ni81Fe19(x)/Cu(5 nm) suggests that the buried magnetic interfaces are better generators of second-harmonic than the air-exposed Ni81Fe19 surface. There is a distinct decay in the magnetic component of the second-harmonic intensity for film thicknesses below 2 nm. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. QUANTUM CORP,LOUISVILLE,CO 80028. RP Crawford, TM (reprint author), UNIV COLORADO,DEPT PHYS,CONDENSED MATTER LAB,BOULDER,CO 80309, USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 13 TC 8 Z9 8 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4354 EP 4358 DI 10.1063/1.364820 PN 2A PG 5 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600232 ER PT J AU Lind, DM Erwin, RW Borchers, JA Lee, SH Majkrzak, CF AF Lind, DM Erwin, RW Borchers, JA Lee, SH Majkrzak, CF TI Spin structure in ferrimagnetic/antiferromagnetic Fe3O4/NiO superlattices SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. NR 0 TC 1 Z9 1 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4488 EP 4488 DI 10.1063/1.364883 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600285 ER PT J AU Hua, SZ Lashmore, DS Swartzendruber, LJ Egelhoff, WF Raj, K Chopra, HD AF Hua, SZ Lashmore, DS Swartzendruber, LJ Egelhoff, WF Raj, K Chopra, HD TI Observation of domain dynamics in giant magnetoresistive Co-Cu-based polycrystalline multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB A high resolution interference-contrast colloid technique has been used to investigate domain dynamics associated with the antiferromagnetic (AF)double left right arrow ferromagnetic (F) magnetization reversal processes in polycrystalline Co-Cu-based magnetic multilayers exhibiting giant magnetoresistance. The magnetization reversal was found to be local and nonuniform in nature: within each grain reversal occurs by nucleation of one or more reversed domains at its grain boundary, and different grains require different critical applied field values for wall nucleation, and their subsequent motion. Significantly, the domain dynamics associated with F double right arrow AF reversal were found to have different characteristics in comparison with the AF double right arrow F magnetization reversal. These results indicate asymmetrical giant magnetoresistance loop characteristics at the mesoscopic scale. (C) 1997 American Institute of Physics. C1 MAT INNOVAT INC,W LEBANON,NH 03784. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. FERROFLUID CORP,NASHUA,NH 03061. UNIV MARYLAND,DEPT MAT & NUCL ENGN,COLLEGE PK,MD 20742. NR 8 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4582 EP 4584 DI 10.1063/1.364749 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600320 ER PT J AU Skanthakumar, S Lynn, JW Dogan, F AF Skanthakumar, S Lynn, JW Dogan, F TI Spin dynamics of Er-3+ in ErBa2Cu3O7-delta SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID BEHAVIOR; ER AB Neutron scattering techniques are used to study the magnetic excitations of the Er ions in superconducting ErBa2Cu3O7, a system where the Er ions order antiferromagnetically at T-N = 0.62 K and the sublattice magnetization obeys the relation for a 2D S = 1/2 Ising model. Our data, which were taken on a cold neutron triple axis spectrometer using a horizontally focusing analyzer, reveal that there is a large gap of about 0.20 meV in the excitation spectrum, about four times the thermal energy kT(N), as expected for an Ising system. However, we also observe dispersion of the spin waves in the a-b plane. These excitations are found to renormalize with temperature and only diffuse paramagnetic scattering is observed well above the ordering temperature. (C) 1997 American Institute of Physics. C1 UNIV MARYLAND,DEPT PHYS,CTR SUPERCOND RES,COLLEGE PK,MD 20742. UNIV WASHINGTON,DEPT MAT SCI & ENGN,SEATTLE,WA 98195. RP Skanthakumar, S (reprint author), NATL INST STAND & TECHNOL,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899, USA. NR 9 TC 7 Z9 7 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4934 EP 4936 DI 10.1063/1.365002 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700070 ER PT J AU Lin, YC Chuang, WY Li, WH Lee, KC Lynn, JW Yang, CL Ku, HC AF Lin, YC Chuang, WY Li, WH Lee, KC Lynn, JW Yang, CL Ku, HC TI Crystal structure and magnetic ordering of Pr in (Pb0.5Cu0.5)(2)(Ba0.5Sr0.5)(2)PrCu2O8 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB The crystal structure of polycrystalline PbBaSrPrCu3O8 was studied using high resolution neutron diffraction. Rietveld refinement of the diffraction pattern shows that the compound crystallizes into the Tl2Ba2YCu2O8 2212-type structure. The Pb and Cu atoms in the two (Pb,Cu)O layers are randomly mixed to form two (Pb0.5Cu0.5)O layers, and the Pa and Sr atoms are also randomly mixed to form two (Ba0.5Sr0.5)O layers, resulting in (Pb0.5Cu0.5)(2)(Ba0.5Sr0.5)(2)PrCu2O8. The magnetic ordering of the Pr ions was also studied using magnetic neutron diffraction and ac susceptibility measurements. At low temperatures, magnetic peaks presumably originating from the Pr spin ordering were observed at the {1/2 1/2 1/2 1/2}, {1/2 1/2 3/2}, and {1/2 1/2 5/2} positions. The Pr spins order at T-N approximate to 9 K with the moment direction along the c axis and the nearest-neighbor spins coupled antiferromagnetically. A cusp associated with the antiferromagnetic ordering at T-N is also clearly observed in ac susceptibility measurements. (C) 1997 American Institute of Physics. C1 NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. NATL TSING HUA UNIV,DEPT PHYS,HSINCHU 300,TAIWAN. RP Lin, YC (reprint author), NATL CENT UNIV,DEPT PHYS,CHUNGLI 32054,TAIWAN. NR 11 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4940 EP 4942 DI 10.1063/1.365004 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700072 ER PT J AU Silva, TJ Kos, AB AF Silva, TJ Kos, AB TI Nonreciprocal differential detection method for scanning Kerr-effect microscopy SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB We describe an optical detection scheme for scanning Kerr-effect microscopy (SKEM) which does not require modification of the magnetic state of a sample for domain observation. The scheme exploits the nonreciprocal nature of the magneto-optic Kerr effect (MOKE) to distinguish polarization rotation due to sample magnetization from other spurious sources, such as sample roughness and birefringence of the microscope optics. We present SKEM images of domain structures in lithographically patterned Ni81Fe19 elements which demonstrate the imaging capabilities of the new detection scheme for materials with typical MOKE magnitudes. RP Silva, TJ (reprint author), NATL INST STAND & TECHNOL,DIV 814 05,325 BROADWAY,BOULDER,CO 80303, USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 12 TC 10 Z9 10 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5015 EP 5017 DI 10.1063/1.365550 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700106 ER PT J AU Gornakov, VS Nikitenko, VI Bennett, LH Brown, HJ Donahue, MJ Egelhoff, WF McMichael, RD Shapiro, AJ AF Gornakov, VS Nikitenko, VI Bennett, LH Brown, HJ Donahue, MJ Egelhoff, WF McMichael, RD Shapiro, AJ TI Experimental study of magnetization reversal processes in nonsymmetric spin valve SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID FILMS AB We have investigated a nonsymmetric bottom giant magnetoresistance spin valve with the structure Si/NiO/Co/Cu/Co/Ta, as well as single ferromagnetic Co layers on antiferromagnetic NiO, with or without a nonmagnetic Cu spacer. Magnetic hysteresis loops have been measured by SQUID magnetometry, and magnetic domain structures have been imaged using an advanced magneto-optical indicator film (MOIF) technique. The MOIF technique demonstrated that the first stage of magnetization reversal is characterized by nucleation of many microdomains. With increasing reversed field, the domain walls move over small distances (5-20 mu m) until annihilation. The domain size was observed to increase with the thickness of the Co layer. When an alternating magnetic field was applied, the domain structure was dramatically changed. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. GEORGE WASHINGTON UNIV,INST MAGNET RES,ASHBURN,VA 22011. RP Gornakov, VS (reprint author), RUSSIAN ACAD SCI,INST SOLID STATE PHYS,CHERNOGOLOVKA 142432,MOSCOW,RUSSIA. RI McMichael, Robert/J-8688-2012; OI McMichael, Robert/0000-0002-1372-664X NR 11 TC 19 Z9 19 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5215 EP 5217 DI 10.1063/1.364954 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700186 ER PT J AU Vajda, F Bennett, LH Swartzendruber, LJ Rugkwamsook, P DellaTorre, E AF Vajda, F Bennett, LH Swartzendruber, LJ Rugkwamsook, P DellaTorre, E TI Experimental validation of the Preisach accommodation properties of recording media SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID MODEL; IDENTIFICATION AB The characterization of accommodation plays an important role in determining both the archival and the recording properties of magnetic recording materials. In this article the basic properties of the recently proposed accommodation paper were experimentally investigated on a commercial flexible disk material. The new technique of operative field accommodation was used in our measurements. It was seen that the direction of the drift in remanence depends on the initial field reversal and that the amount of accommodation depends not only on the width of the minor loop, but the extrema values, as well. Although the amount of accommodation depends on the field reversal points, it was seen that for any initial field reversal point, when cycling between the same operative field values, the stable minor loop is always the same. It was found that if \h(1)\=\h(2)\, that is, the accommodation process is symmetrical in the operative field, the stable minor loop is also symmetrical. The amount of accommodation was found to be maximized for a process in which \h(1)\=\h(2)\=h(i). The latter property could be utilized to accurately measure the accommodation parameter, beta. (C) 1997 American Institute of Physics. C1 GEORGE WASHINGTON UNIV, INST MAGNET RES, ASHBURN, VA 22011 USA. NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. RP DIGITAL MEASUREMENT SYST INC, BURLINGTON, MA 01803 USA. NR 12 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5227 EP 5229 DI 10.1063/1.364475 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700190 ER PT J AU McMichael, RD Donahue, MJ AF McMichael, RD Donahue, MJ TI Micromagnetic computational standard problem SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 NIST,DIV MET,GAITHERSBURG,MD 20899. RI McMichael, Robert/J-8688-2012 NR 0 TC 2 Z9 2 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5242 EP 5242 DI 10.1063/1.364955 PN 2B PG 1 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700195 ER PT J AU Bodeker, P Sonntag, P Schreyer, A Zabel, H Borchers, J Hamacher, K Kaiser, H AF Bodeker, P Sonntag, P Schreyer, A Zabel, H Borchers, J Hamacher, K Kaiser, H TI Effect of Fe cap layers on the spin density waves in epitaxial Cr(001) films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID CHROMIUM AB We have investigated proximity effects of Fe layers on the spin density waves (SDW) and the concomitant charge density waves or strain waves in thin epitaxial Cr[001] films using synchrotron and neutron scattering. Unlike in bulk Cr we observe a strong anisotropic occupation of the three possible SDWs with their wave vectors Q pointing along the {001} directions. In a pure 3000 Angstrom thick Cr[001] film, the SDW exhibits an almost complete out-of-plane orientation, whereas in a Cr film of the same thickness capped by a 20 Angstrom Fe layer the SDW becomes completely reoriented with Q now propagating in the plane. This SDW is preserved over the entire temperature range from 10 K up to the Neel temperature of about 311 K. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. UNIV MISSOURI,RES REACTOR,COLUMBIA,MO 65211. RP Bodeker, P (reprint author), RUHR UNIV BOCHUM,D-44780 BOCHUM,GERMANY. RI Zabel, Hartmut/C-1994-2009 NR 19 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5247 EP 5249 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700198 ER PT J AU Kepa, H Giebultowicz, TM Goldman, KI Nunez, V Majkrzak, CF Springholz, G Bauer, G AF Kepa, H Giebultowicz, TM Goldman, KI Nunez, V Majkrzak, CF Springholz, G Bauer, G TI Polarized neutron diffraction studies of antiferromagnetic EuTe/PbTe superlattices SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract ID INTERLAYER C1 OREGON STATE UNIV,CORVALLIS,OR 97331. NIST,GAITHERSBURG,MD 20899. JOHANNES KEPLER UNIV,A-4040 LINZ,AUSTRIA. NR 2 TC 1 Z9 1 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5373 EP 5373 DI 10.1063/1.364601 PN 2B PG 1 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700249 ER PT J AU Erwin, RW Lynn, JW Borchers, JA Peng, JL Greene, RL AF Erwin, RW Lynn, JW Borchers, JA Peng, JL Greene, RL TI Correlation length in La1-xCaxMnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. UNIV MARYLAND,COLLEGE PK,MD 20742. NR 0 TC 1 Z9 1 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5487 EP 5487 DI 10.1063/1.364574 PN 2B PG 1 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700291 ER PT J AU Lynn, JW Erwin, RW Borchers, JA Santoro, A Huang, Q Peng, JL Greene, RL AF Lynn, JW Erwin, RW Borchers, JA Santoro, A Huang, Q Peng, JL Greene, RL TI Magnetic, structural, and spin dynamical properties of La1-xCaxMnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID FILMS AB Neutron scattering has been used to study the magnetic order, spin dynamics, and structural properties of La1-xCaxMnO3 in the ferromagnetic regime (0T-C. A magnetic field strongly reduces this quasielastic scattering, shifting the spectral weight into the spin wave component of the fluctuation spectrum. (C) 1997 American Institute of Physics. C1 NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. UNIV MARYLAND,MAT ENGN PROGRAM,COLLEGE PK,MD 20742. UNIV MARYLAND,CTR SUPERCONDUCT RES,COLLEGE PK,MD 20742. RP Lynn, JW (reprint author), UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742, USA. NR 14 TC 40 Z9 41 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5488 EP 5490 DI 10.1063/1.364576 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700293 ER PT J AU VasiliuDoloc, L Lynn, JW Moudden, AH deLeonGuevara, AM Revcolevschi, A AF VasiliuDoloc, L Lynn, JW Moudden, AH deLeonGuevara, AM Revcolevschi, A TI Neutron scattering investigation of the structure and spin dynamics in La0.85Sr0.15MnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID MAGNETIC-FIELD; LA1-XSRXMNO3; MAGNETORESISTANCE; RESISTIVITY; TRANSITION; FILMS AB We have performed diffraction and inelastic neutron scattering experiments on La0.85Sr0.15MnO3 single crystal. In the ferromagnetic phase of this system (T-C=235 K) the long wavelength dispersion relation along the (0,1,0) direction is well represented by E=E-0+Dq(2), but with the spin wave spectrum almost gapless (E-0<0.1 meV), and with D-T=0=83.75+/-0.36 meV Angstrom(2). The spin-wave stiffness constant D(T) exhibits a power law behavior as a function of temperature, and appears to collapse as T-->T-C. An orthorhombic-rhombohedral structural phase transition is observed at T-s = 360 K, and exhibits a hysteretic character suggesting a first-order transformation. Anomalies in magnetization measurements and Bragg peak intensities indicate the existence of a second phase transition at T=200 K. (C) 1997 American Institute of Physics. C1 UNIV MARYLAND,CTR SUPERCONDUCT RES,COLLEGE PK,MD 20742. CTR ETUD SACLAY,CNRS,CEA,LAB LEON BRILLOUIN,F-91191 GIF SUR YVETTE,FRANCE. UNIV PARIS 11,CHIM SOLIDE LAB,F-91405 ORSAY,FRANCE. RP VasiliuDoloc, L (reprint author), NATL INST STAND & TECHNOL,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899, USA. NR 24 TC 21 Z9 22 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5491 EP 5493 DI 10.1063/1.364846 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700294 ER PT J AU Moudden, AH VasiliuDoloc, L deLeonGuevara, AM Pinsard, L Revcolevschi, A AF Moudden, AH VasiliuDoloc, L deLeonGuevara, AM Pinsard, L Revcolevschi, A TI Spin dynamics of lightly doped La1-xSrxMnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 CTR ETUD SACLAY,CNRS,CEA,LAB LEON BRILLOUIN,F-91191 GIF SUR YVETTE,FRANCE. NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. UNIV PARIS 11,CHIM SOLIDE LAB,F-91405 ORSAY,FRANCE. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5494 EP 5494 DI 10.1063/1.364577 PN 2B PG 1 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700295 ER PT J AU Cronin, MF McPhaden, MJ AF Cronin, MF McPhaden, MJ TI The upper ocean heat balance in the western equatorial Pacific warm pool during September-December 1992 SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA-SURFACE TEMPERATURE; 1986-87 EL-NINO; WIND BURSTS; MIXED LAYER; TOGA COARE; VARIABILITY; 140-DEGREES-W; RADIATION; BUDGET; MODELS AB The upper ocean heat budget in the western equatorial Pacific warm pool is analyzed for a 3-month period from mid-September through mid-December 1992 using data from the Tropical Atmosphere Ocean (TAO) array enhanced for the Coupled Ocean Atmosphere Response Experiment. Surface heat and moisture fluxes were measured from a centrally located TAO current meter mooring at 0 degrees, 156 degrees E. Lateral heat advection was estimated using temperature data from moorings within 150-250 km of 0 degrees, 156 degrees E. Mixing was estimated as the residual of the heat balance and compared to estimates of mixing based on the Niiler-Kraus parameterization of entrainment mixing. The analysis shows that for the diurnal cycle and for daily to weekly timescale variations like those associated with westerly wind bursts, the sea surface temperature (SST) variability is to a large extent controlled by shortwave radiation and latent heat flux. However, three-dimensional processes can also be important. For example, in early October 1992, the SST at 0 degrees, 156 degrees E increased by nearly 1 degrees C in 7 days due predominately to westward heat advection. Also, the dynamical response to a moderately strong wind burst in late October 1992 included a deepening of the pycnocline, which affected the rate of entrainment cooling, and a reversal of the surface current, which affected the zonal heat advection. The importance of three-dimensional processes (particularly heat advection) in the warm-pool heat balance during this 3-month study period is confirmed by comparing the observed temperature variability with that simulated by a one-dimensional mixed layer model. RP Cronin, MF (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. RI McPhaden, Michael/D-9799-2016 NR 51 TC 103 Z9 106 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 15 PY 1997 VL 102 IS C4 BP 8533 EP 8553 DI 10.1029/97JC00020 PG 21 WC Oceanography SC Oceanography GA WU659 UT WOS:A1997WU65900004 ER PT J AU McKenna, GB Crissman, JM AF McKenna, GB Crissman, JM TI Temperature and crosslinking effects on the swelling of poly(isoprene) in isopiestic conditions SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE crosslinked rubber; Flory-Rehner hypothesis; gels; networks; polymer; rubber elasticity; swelling; swelling activity parameter; thermodynamics ID RUBBER ELASTICITY; POLY(VINYL ALCOHOL); POLYMER NETWORKS; POLY(DIMETHYLSILOXANE); DEPENDENCE; HYDROGELS; GELS; CHI AB Isopiestic measurements of solvent uptake have been made in the synthetic isoprene/benzene system for both crosslinked and uncrosslinked polymers in order to revisit the question of the swelling activity parameter S. Both the nonzero value of S at zero swelling and the appearance of a peak in S vs. degree of swelling have been observed in some solvent/rubber pairs and we here investigate both the crosslink and temperature dependencies of these phenomena. The data analysis is an extension of prior work from this laboratory using continuum thermodynamics concepts and avoiding molecular models in an attempt to establish the fundamental phenomenology of the process and the validity or lack of validity of the hypothesis that the mixing and elastic contributions to the free energy of networks are separable. We present results from measurements in benzene vapors at temperatures between 10 and 55 degrees C for an uncrosslinked rubber and rubbers crosslinked with 1, 5, 10, and 15 parts per hundred dicumyl peroxide. (C) 1997 John Wiley & Sons, Inc. RP McKenna, GB (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 33 TC 18 Z9 18 U1 1 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD APR 15 PY 1997 VL 35 IS 5 BP 817 EP 826 DI 10.1002/(SICI)1099-0488(19970415)35:5<817::AID-POLB10>3.0.CO;2-D PG 10 WC Polymer Science SC Polymer Science GA WQ019 UT WOS:A1997WQ01900010 ER PT J AU Jones, PW Hamilton, K Wilson, RJ AF Jones, PW Hamilton, K Wilson, RJ TI A very high resolution general circulation model simulation of the global circulation in austral winter SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GRAVITY-WAVE DRAG; HORIZONTAL RESOLUTION; SENSITIVITY; STRATOSPHERE; CLIMATE; TROPOSPHERE AB This paper discusses a simulation obtained with the Geophysical Fluid Dynamics Laboratory ''SKYHI'' troposphere-stratosphere-mesosphere general circulation model run at very high horizontal resolution (similar to 60-km grid spacing) and without any parameterization of subgrid-scale gravity wave drag. The results are for a period around the austral winter solstice, and the emphasis is on the simulated Southern Hemisphere (SH) winter circulation. Comparisons are made with results obtained from lower horizontal resolution versions of the same model. The focus in this paper is on two particularly striking features of the high-resolution simulation: the extratropical surface winds and the winter polar middle atmospheric vortex. In the extratropical SH, the simulated surface westerlies and meridional surface pressure gradients in the high-resolution model are considerably stronger than observed and are stronger than those simulated at lower horizontal resolution. In the middle atmosphere, the high-resolution model produces a simulation of the zonal mean winter polar vortex that is considerably improved over that found with lower resolution models (although it is still significantly affected by the usual cold pole bias). Neither the improvement of the middle atmospheric polar vortex simulation nor the deterioration of the simulation of surface winds with increased model resolution shows a clear convergence, even at the similar to 60-km grid spacing employed here. C1 PRINCETON UNIV, NOAA, GFDL, PRINCETON, NJ 08542 USA. LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM USA. NR 29 TC 21 Z9 21 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR 15 PY 1997 VL 54 IS 8 BP 1107 EP 1116 DI 10.1175/1520-0469(1997)054<1107:AVHRGC>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV759 UT WOS:A1997WV75900011 ER PT J AU Germer, TA Kolasinski, KW Stephenson, JC Richter, LJ AF Germer, TA Kolasinski, KW Stephenson, JC Richter, LJ TI Depletion-electric-field-induced second-harmonic generation near oxidized GaAs(001) surfaces SO PHYSICAL REVIEW B LA English DT Article ID OPTICAL 2ND-HARMONIC GENERATION; CUBIC CENTROSYMMETRIC CRYSTALS; GAAS 100 SURFACES; 3RD-HARMONIC GENERATION; PHENOMENOLOGICAL THEORY; SEMICONDUCTOR SURFACES; GAAS(100) SURFACE; TIO2 ELECTRODES; PROBE; AIR AB Second-order nonlinear mixing is evaluated as a probe of the depletion electric field in the nearsurface region of GaAs(001). A phenomenological model is presented whereby the nonlinear susceptibility is expanded in the depletion electric field. For GaAs, three terms contribute to the observed nonlinear mixing: the dipole-allowed bulk contribution and first- and second-order contributions in the depletion electric field. All three contributions can be isolated by a combination of rotational anisotropy and photomodulation studies. The second-harmonic signal from oxidized GaAs(001) surfaces was measured as a function of azimuthal sample orientation, photomodulation, and dopant density for fundamental photon energies in the region 1.17-1.51 eV. The first-order depletion-electric-field contribution dominates the second-order contribution, and can be comparable to the intrinsic bulk contribution for high surface fields. The results rule out significant contributions arising from either bulk electric quadrupole or surface dipole effects. C1 UNIV BIRMINGHAM,SCH CHEM,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND. RP Germer, TA (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. RI Schaff, William/B-5839-2009; Kolasinski, Kurt/A-3342-2008; Richter, Lee/N-7730-2016 OI Kolasinski, Kurt/0000-0002-9469-2700; Richter, Lee/0000-0002-9433-3724 NR 56 TC 28 Z9 28 U1 2 U2 12 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10694 EP 10706 DI 10.1103/PhysRevB.55.10694 PG 13 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300075 ER PT J AU McDaniel, EB Hsu, JWP Goldner, LS Tonucci, RJ Shirley, EL Bryant, GW AF McDaniel, EB Hsu, JWP Goldner, LS Tonucci, RJ Shirley, EL Bryant, GW TI Local characterization of transmission properties of a two-dimensional photonic crystal SO PHYSICAL REVIEW B LA English DT Article ID SCANNING OPTICAL MICROSCOPY; BAND-STRUCTURE; WAVE-GUIDES; ARRAY AB We use a near-field scanning optical microscope to study optical transmission through a two-dimensional triangular photonic crystal. Spatial variations in the intensity of Light coupled through the sample depend on the photon energy and the numerical aperture of the collection optics. We discuss the relationship between the observed dependence and the local structure of the optical modes in the crystal. Features in the data arising from modes with Fourier components inside and outside the first Brillouin zone can be distinguished by this technique. C1 UNIV VIRGINIA,DEPT PHYS,CHARLOTTESVILLE,VA 22901. NIST,GAITHERSBURG,MD 20899. USN,RES LAB,WASHINGTON,DC 20375. NR 22 TC 32 Z9 33 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10878 EP 10882 DI 10.1103/PhysRevB.55.10878 PG 5 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300096 ER PT J AU Biggerstaff, BJ Tweedie, RL AF Biggerstaff, BJ Tweedie, RL TI Incorporating variability in estimates of heterogeneity in the random effects model in meta-analysis SO STATISTICS IN MEDICINE LA English DT Article ID TRIALS AB When combining results from separate investigations in a meta-analysis, random effects methods enable the modelling of differences between studies by incorporating a heterogeneity parameter tau(2) that accounts explicitly for across-study variation. We develop a simple form for the variance of Cochran's homogeneity statistic Q, leading to interval estimation of tau(2) utilizing an approximating distribution for Q; this enables us to extend the point estimation of DerSimonian and Laird. We also develop asymptotic likelihood methods and compared them with this method. We then use these approximating distributions to give a new method of calculating the weight given to the individual studies' results when estimating the overall mean which takes into account variation in these point estimates of tau(2). Two examples illustrate the methods presented, where we show that the new weighting scheme is between the standard fixed and random effects models in down-weighting the results of large studies and up-weighting those of small studies. (C) 1997 by John Wiley & Sons, Ltd. C1 COLORADO STATE UNIV,DEPT STAT,FT COLLINS,CO 80523. RP Biggerstaff, BJ (reprint author), NATL INST STAND & TECHNOL,STAT ENGN DIV,BOULDER,CO 80303, USA. NR 26 TC 139 Z9 142 U1 0 U2 8 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0277-6715 J9 STAT MED JI Stat. Med. PD APR 15 PY 1997 VL 16 IS 7 BP 753 EP 768 DI 10.1002/(SICI)1097-0258(19970415)16:7<753::AID-SIM494>3.3.CO;2-7 PG 16 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 WU162 UT WOS:A1997WU16200004 PM 9131763 ER PT J AU Brown, EB Iyer, HK Wang, CM AF Brown, EB Iyer, HK Wang, CM TI Tolerance intervals for assessing individual bioequivalence SO STATISTICS IN MEDICINE LA English DT Article ID COMPARATIVE BIOAVAILABILITY TRIALS; CONFIDENCE-INTERVALS; TRANSFORMATION; EQUIVALENCE; POPULATION; CRITERIA AB Evaluation of equivalence of two formulations of a drug typically entails the comparison of average bioavailabilities. Recently, however, authors have become aware that this may be insufficient to assess individual bioequivalence, that is, interchangeability of formulations on an individual basis. This paper outlines a tolerance interval procedure to assess individual bioequivalence based on a model that includes a subject by formulation interaction. We give methods for several higher-order cross-over designs along with examples. (C) 1997 by John Wiley & Sons, Ltd. C1 NATL INST STAND & TECHNOL,STAT ENGN DIV,BOULDER,CO 80303. RP Brown, EB (reprint author), COLORADO STATE UNIV,DEPT STAT,FT COLLINS,CO 80523, USA. NR 28 TC 11 Z9 11 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0277-6715 J9 STAT MED JI Stat. Med. PD APR 15 PY 1997 VL 16 IS 7 BP 803 EP 820 DI 10.1002/(SICI)1097-0258(19970415)16:7<803::AID-SIM499>3.3.CO;2-V PG 18 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 WU162 UT WOS:A1997WU16200008 PM 9131767 ER PT J AU Saha, HP Lin, D AF Saha, HP Lin, D TI Theoretical study of the valence and core photoionization of a three-electron system from lithium to neon SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID K-SHELL PHOTOIONIZATION; CROSS-SECTIONS; PHOTOELECTRON SPECTROMETRY; ATOMIC LITHIUM; BERYLLIUM; SPECTRUM; SODIUM AB The multiconfiguration Hartree-Fock (MCHF) method for continuum wavefunctions is used to study the photoionization of lithium and ions of its isoelectronic sequence for photon energies from 0.1 to 250 Ryd. Electron correlation and polarization effects in the initial and final states and relaxation and correlation in the final ionic stales, which are found to be very important in the valence- and K-shell partial photoionization cross sections, have been taken into account accurately in an ab initio manner through the configuration interaction procedure. The present results are compared with available experimental measurements and accurate theoretical data for a limited energy range and are found to be in good agreement. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Saha, HP (reprint author), UNIV CENT FLORIDA,DEPT PHYS,ORLANDO,FL 32816, USA. NR 29 TC 2 Z9 2 U1 2 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD APR 14 PY 1997 VL 30 IS 7 BP 1651 EP 1667 DI 10.1088/0953-4075/30/7/006 PG 17 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WV062 UT WOS:A1997WV06200006 ER PT J AU Raithel, G Birkl, G Phillips, WD Rolston, SL AF Raithel, G Birkl, G Phillips, WD Rolston, SL TI Compression and parametric driving of atoms in optical lattices SO PHYSICAL REVIEW LETTERS LA English DT Article ID LIGHT AB Using Bragg scattering we study classical squeezing and wave packet oscillations of the atomic center-of-mass motion of cesium atoms trapped in 1D and 3D optical lattices. A sudden increase of the potential depth leads to wave packets substantially more localized than in steady state, and subsequent breathing-mode oscillations with a decay rate that under some conditions is remarkably slow. We also study the response of the atoms to parametric driving of the center-of-mass motion. Our results are in agreement with Monte Carlo simulations. RP Raithel, G (reprint author), NIST, PHYS A167, GAITHERSBURG, MD 20899 USA. RI rolston, steven/L-5175-2013 OI rolston, steven/0000-0003-1671-4190 NR 17 TC 49 Z9 49 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 2928 EP 2931 DI 10.1103/PhysRevLett.78.2928 PG 4 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300015 ER PT J AU Weetall, HH AF Weetall, HH TI Biosensor technology: Present state and future perspectives. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 1 EP SCHB PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703722 ER PT J AU Kasianowicz, JJ AF Kasianowicz, JJ TI Detecting and characterizing analytes with an ion channel SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract ID PROTEIN C1 NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 2 EP SCHB PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703723 ER PT J AU Coxon, B Sari, N Mulard, LA Kovac, P Glaudemans, CPJ Pozsgay, V AF Coxon, B Sari, N Mulard, LA Kovac, P Glaudemans, CPJ Pozsgay, V TI Investigation by NMR spectroscopy and molecular mechanics of the conformations of some modified disaccharide antigens for Shigella dysenteriae type 1. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. NIDDK,MED CHEM LAB,NIH,BETHESDA,MD 20892. NICHHD,DEV & MOL IMMUN LAB,NIH,BETHESDA,MD 20892. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 27 EP BIOT PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18500622 ER PT J AU Taylor, JJ Joel, EC Goodway, M Vocke, RD AF Taylor, JJ Joel, EC Goodway, M Vocke, RD TI Geological implications of the lead isotope data on ores from the Great Orme mine, North Wales SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV LIVERPOOL,SACOS,LIVERPOOL L69 3BX,MERSEYSIDE,ENGLAND. NIST,DIV ANALYT CHEM,GAITHERSBURG,MD 20899. SMITHSONIAN INST,CAL,MSC,WASHINGTON,DC 20560. NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 34 EP GEOC PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18503477 ER PT J AU Nyden, MR AF Nyden, MR TI Applications of molecular dynamics to the study of thermal degradation in polymers SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899. NR 0 TC 2 Z9 2 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 49 EP COMP PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502681 ER PT J AU Blakeslee, DM Rumble, JR AF Blakeslee, DM Rumble, JR TI Achieving database quality - With special emphasis on the delivery of chemical information. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 56 EP CINF PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502134 ER PT J AU Xia, J Gebeyehu, G Gaigalas, A Erber, EF Wergin, WP AF Xia, J Gebeyehu, G Gaigalas, A Erber, EF Wergin, WP TI Quasi-elastic light scattering, electrophoretic light scattering, fluorescence, thermal analysis and electron microscopic studies of DNA-liposome complexes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 LTI,GAITHERSBURG,MD 20884. NIST,GAITHERSBURG,MD 20877. USDA,BELTSVILLE,MD 20705. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 57 EP COLL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502299 ER PT J AU Rudich, Y Talukdar, RK Ravishankara, AR AF Rudich, Y Talukdar, RK Ravishankara, AR TI Heterogeneous chemistry of the NO3 radical in the marine boundary layer SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA,AERON LAB,BOULDER,CO 80309. RI Rudich, Yinon/K-1498-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 59 EP ENVR PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18503090 ER PT J AU Lin, MY Sirota, EB Gang, H AF Lin, MY Sirota, EB Gang, H TI Neutron scattering characterization of asphaltene particles. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. EXXON RES & ENGN CO,ANNANDALE,NJ 08801. RI Sirota, Eric/A-7633-2009 NR 0 TC 5 Z9 5 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 66 EP FUEL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18503353 ER PT J AU Tchatchoua, C Ji, Q Srinivasan, SA Ghassemi, H Yoon, TH MartinezNunez, M Kashiwagi, T McGrath, JE AF Tchatchoua, C Ji, Q Srinivasan, SA Ghassemi, H Yoon, TH MartinezNunez, M Kashiwagi, T McGrath, JE TI Flame resistant epoxy networks based on aryl phosphine oxide containing diamines flame resistant epoxy networks based on aryl phosphine oxide containing diamines. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 VIRGINIA POLYTECH INST & STATE UNIV,DEPT CHEM,BLACKSBURG,VA 24061. NSF SCI & TECHNOL CTR,HIGH PERFORMANCE POLYMER ADHES & COMPOSITES,BLACKSBURG,VA 24061. NIST,MAT & FIRE RES GRP,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 66 EP POLY PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18702803 ER PT J AU Howard, CJ Russell, A Atkinson, R Calvert, J AF Howard, CJ Russell, A Atkinson, R Calvert, J TI Air quality effects of the winter oxyfuel program. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA,AERON LAB,BOULDER,CO 80303. GEORGIA INST TECHNOL,DEPT CIVIL & ENVIRONM ENGN,ATLANTA,GA 30332. UNIV CALIF RIVERSIDE,STATEWIDE AIR POLLUT RES CTR,RIVERSIDE,CA 92521. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 97 EP ENVR PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18503128 ER PT J AU Glazier, SA Campbell, E Campbell, W AF Glazier, SA Campbell, E Campbell, W TI Measurement of nitrate by standard addition using a nitrate reductase-based electrode. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. NITRATE ELIMINAT CO INC,LAKE LINDEN,MI 49931. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 124 EP ANYL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18500479 ER PT J AU DiMarzio, EA AF DiMarzio, EA TI The use of configurational entropy to derive the kinetic properties of polymer glasses. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 126 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703442 ER PT J AU Schultheisz, CR McKenna, GB AF Schultheisz, CR McKenna, GB TI Volume recovery and physical aging in glassy polycarbonate following temperature jumps. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 131 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703447 ER PT J AU Cole, KD McKenney, K Blakesley, RW AF Cole, KD McKenney, K Blakesley, RW TI Electrochromatography of DNA: Preparative separations of different plasmid physical forms. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. INST GENOM RES,ROCKVILLE,MD. LIFE TECHNOL INC,GAITHERSBURG,MD 20897. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 159 EP BIOT PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18500752 ER PT J AU Materer, N Goodman, RS Leone, SR AF Materer, N Goodman, RS Leone, SR TI Pulsed laser single-photon ionization of chlorinated silicon products during etching of Si(100) SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. UNIV COLORADO,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 160 EP COLL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502400 ER PT J AU Coxon, B Sari, N Holden, MJ Vilker, V AF Coxon, B Sari, N Holden, MJ Vilker, V TI Characterization 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. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 182 EP BIOT PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18500775 ER PT J AU Roitberg, A AF Roitberg, A TI Modeling the interactions between putidaredoxin and cytochrome P450cam. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. NR 1 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 200 EP BIOT PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18500793 ER PT J AU Stevens, WJ Gilson, HS AF Stevens, WJ Gilson, HS TI A computational study of strong, anionic hydrogen bonds. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,CTR ADV RES BIOTECHNOL,GAITHERSBURG,MD 20899. NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 200 EP COMP PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502832 ER PT J AU Goldberg, RN Tewari, YB AF Goldberg, RN Tewari, YB TI Thermodynamics of enzyme-catalyzed reactions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 212 EP BIOT PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18500805 ER PT J AU Weldon, MK Eng, J Bent, BE Chabal, YJ Struck, LM AF Weldon, MK Eng, J Bent, BE Chabal, YJ Struck, LM TI Vibrational studies of the water-induced oxidation of Si(100). SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 AT&T BELL LABS,LUCENT TECHNOL,MURRAY HILL,NJ 07974. COLUMBIA UNIV,NEW YORK,NY 10027. NIST,GAITHERSBURG,MD 20899. RI Chabal, Yves/A-5998-2011 OI Chabal, Yves/0000-0002-6435-0347 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 218 EP COLL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502459 ER PT J AU OConnell, PA McKenna, GB AF OConnell, PA McKenna, GB TI Time - Temperature and time - Strain superposition in polycarbonate below Tg. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract DE glass transition; KWW function; polycarbonate; stress relaxation; time-strain superposition; time-temperature superposition C1 NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 220 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703536 ER PT J AU Lin, MY Hanley, HJM Straty, GC Muzny, CD Sinha, SK Peiffer, DG AF Lin, MY Hanley, HJM Straty, GC Muzny, CD Sinha, SK Peiffer, DG TI Simultaneous measurement of viscosity and structure for a rod-like micellar solution. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,BOULDER,CO 80303. ARGONNE NATL LAB,EXPT FACIL DIV,ARGONNE,IL 60439. EXXON RES & ENGN CO,ANNANDALE,NJ 08801. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 271 EP COLL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502512 ER PT J AU Leone, SR AF Leone, SR TI Alignment and control of rovibronic wave packets. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV COLORADO,BOULDER,CO 80309. NIST,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NIST,JILA,BOULDER,CO 80309. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 286 EP PHYS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18702542 ER PT J AU Haralampus, N Northrop, JP Scordalakes, C Ashmore, E Martin, W Kranbuehl, D AF Haralampus, N Northrop, JP Scordalakes, C Ashmore, E Martin, W Kranbuehl, D TI Dynamic Monte Carlo simulation and dielectric measurements of the effect of pore size on the glass transition temperature and the state of the glass. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 COLL WILLIAM & MARY,DEPT CHEM,WILLIAMSBURG,VA 23187. NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 292 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703608 ER PT J AU Sinniah, K Karim, A Douglas, JF ReuttRobey, JE AF Sinniah, K Karim, A Douglas, JF ReuttRobey, JE TI In-situ imaging of swelling of end-grafted polymer layers under variable SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 CALVIN COLL,DEPT CHEM & BIOCHEM,GRAND RAPIDS,MI 49546. NIST,GAITHERSBURG,MD 20899. UNIV MARYLAND,DEPT CHEM & BIOCHEM,COLLEGE PK,MD 20742. RI Reutt-Robey, Janice /C-3517-2009 OI Reutt-Robey, Janice /0000-0002-9309-7854 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 389 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703126 ER PT J AU Gilman, JW Lomakin, S Kashiwagi, T VanderHart, DL Nagy, V AF Gilman, JW Lomakin, S Kashiwagi, T VanderHart, DL Nagy, V TI Characterization of flame retarded polymer combustion chars by solid-state C-13 and Si-29 NMR and EPR. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20988. NR 0 TC 0 Z9 0 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 418 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703155 ER PT J AU Weiss, RA Feng, Y Xie, R Tucker, R Han, CC AF Weiss, RA Feng, Y Xie, R Tucker, R Han, CC TI Phase behavior and structure pinning during phase-separation of polyamide/ionomer blends. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV CONNECTICUT,DEPT CHEM ENGN,STORRS,CT 06269. NIST,DIV POLYMER,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 515 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18703251 ER PT J AU Vanderah, TA AF Vanderah, TA TI Comparative crystal chemistry and subsolidus phase relations in systems of interest for microwave dielectric ceramics SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV CERAM,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 646 EP INOR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18700807 ER PT J AU Tziperman, E AF Tziperman, E TI Inherently unstable climate behaviour due to weak thermohaline ocean circulation SO NATURE LA English DT Article ID MIXED BOUNDARY-CONDITIONS; NORTH-ATLANTIC OCEAN; ATMOSPHERE SYSTEM; WATER; VARIABILITY; MODEL; TEMPERATURE; DRIVEN; CO2 AB The oceanic thermohaline circulation (THC) carries Light, warm surface water polewards and dense, cold deep water equator-wards, thereby transporting a large amount of heat towards the poles and significantly affecting high latitude climate. The THC has been remarkably stable, and its variability quite low over the Holocene period (the past 10,000 years). The much greater climate instability and high-frequency variability recorded in ice(1) and deep-sea(31) cores throughout the preceding 150,000 years has been linked to greater THC variability(2,3). Here we argue, using a global coupled ocean-atmosphere-ice general circulation model with realistic geography, that there is a wide range of weak mean states of the THC that Cannot be stably sustained by the climate system. When the model THC is forced into a state in the unstable range, the THC may rapidly strengthen, collapse or display strong oscillations. The existence of this unstable regime may account for the greater variability of the THC and climate before the Holocene period. C1 PRINCETON UNIV,GEOPHYS FLUID DYNAM LAB,ATMOSPHER & OCEAN SCI PROGRAM,PRINCETON,NJ 08544. RP Tziperman, E (reprint author), WEIZMANN INST SCI,DEPT ENVIRONM SCI,IL-76100 REHOVOT,ISRAEL. NR 31 TC 82 Z9 82 U1 3 U2 8 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 10 PY 1997 VL 386 IS 6625 BP 592 EP 595 DI 10.1038/386592a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WT273 UT WOS:A1997WT27300054 ER PT J AU MahroofTahir, M Keramidas, AD Goldfarb, RB Anderson, OP Miller, MM Crans, DC AF MahroofTahir, M Keramidas, AD Goldfarb, RB Anderson, OP Miller, MM Crans, DC TI Solution and solid state properties of [N-(2-hydroxyethyl)iminodiacetato]vanadium(IV), -(V), and -(IV/V) complexes SO INORGANIC CHEMISTRY LA English DT Article ID MIXED-VALENCE COMPLEXES; CRYSTAL-STRUCTURE; VANADIUM(V) COMPLEXES; LABILE OXOVANADATES; MOLECULAR-STRUCTURE; DIABETES-MELLITUS; CORE; VIV; VV AB A mononuclear vanadium(IV), a mononuclear vanadium(V), and a binuclear mixed valence vanadium(IV/V) complex with the ligand N-(2-hydroxyethyl)iminodiacetic acid (H(3)hida) have been structurally characterized. Crystal data for [VO(Hhida)(H2O)]. CH3OH (1): orthorhombic; P2(1)2(1)2(1); a = 6.940(2), b = 9.745(3), c = 18.539(4) Angstrom; Z = 4. Crystal data for Na[V(O)(2)(Hhida)(2)]. 4H(2)O (2): monoclinic; P2(1)/c; a = 6.333(2), b = 18.796(2), c = 11.5040(10) Angstrom; beta = 102.53(2)degrees; Z = 4. Crystal data for (NH4)[V-2(O)(2)(mu-O)(Hhida)(2)]. H2O (3): monoclinic; C2/c; a = 18.880(2), b = 7.395(2), c = 16.010(2) Angstrom; beta = 106.33(2)degrees; Z = 4. The mononuclear vanadium(IV) and vanadium(V) complexes are formed from the monoprotonated Hhida(2-) ligand, and their structural and magnetic characteristics are as expected for six-coordinate vanadium complexes. An interesting structural feature in these complexes is the fact that the two carboxylate moieties are coordinated trans to one another, whereas the carboxylate moieties are coordinated in a cis fashion in previously characterized complexes. The aqueous solution properties of the vanadium(IV) and -(V) complexes are consistent with their structures. The vanadium(V) complex was previously characterized; in the current study structural characterization in the solid state is provided. X-ray crystallography and magnetic methods show that the mixed valence complex contains two indistinguishable vanadium atoms; the thermal ellipsoid of the bridging oxygen atom suggests a type III complex in the solid state. Magnetic methods show that the mixed valence complex contains a free electron. Characterization of aqueous solutions of the mixed valence complex by UV/vis and EPR spectroscopies suggests that the complex may be described as a type II complex. The Hhida(2-) complexes have some similarities, but also some significant differences, with complexes of related ligands, such as nitrilotriacetate (nta), N-(2-pyridylmethyl)iminodiacetate (pmida), and N-(S)-[1-(2-pyridyl)ethyl]iminodiacetate (s-peida). Perhaps most importantly, the mixed valence Hhida(2-) complex is significantly less stable than the corresponding pmida and s-peida complexes of similar overall charge but very similar in stability to the nta and V2O33+ complexes with higher charges. Thus, there is the potential for designing stable mixed valence dimers. C1 COLORADO STATE UNIV,DEPT CHEM,FT COLLINS,CO 80523. NATL INST STAND & TECHNOL,DIV ELECTROMAGNET TECHNOL,BOULDER,CO 80303. RI Goldfarb, Ronald/A-5493-2011; OI Goldfarb, Ronald/0000-0002-1942-7974; Keramidas, Anastasios/0000-0002-0446-8220 NR 46 TC 84 Z9 85 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 9 PY 1997 VL 36 IS 8 BP 1657 EP 1668 DI 10.1021/ic9610243 PG 12 WC Chemistry, Inorganic & Nuclear SC Chemistry GA WT552 UT WOS:A1997WT55200021 ER PT J AU Peterlinz, KA Georgiadis, RM Herne, TM Tarlov, MJ AF Peterlinz, KA Georgiadis, RM Herne, TM Tarlov, MJ TI Observation of hybridization and dehybridization of thiol-tethered DNA using two-color surface plasmon resonance spectroscopy SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID REAL-TIME DETECTION; BIOSENSOR; STRATEGY; SENSOR C1 BOSTON UNIV, DEPT CHEM, BOSTON, MA 02215 USA. NATL INST STAND & TECHNOL, PROC MEASUREMENTS DIV, GAITHERSBURG, MD 20899 USA. NR 25 TC 404 Z9 409 U1 1 U2 65 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 9 PY 1997 VL 119 IS 14 BP 3401 EP 3402 DI 10.1021/ja964326c PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA WT419 UT WOS:A1997WT41900036 ER PT J AU deGouw, JA Krishnamurthy, M Leone, SR AF deGouw, JA Krishnamurthy, M Leone, SR TI The mobilities of ions and cluster ions drifting in polar gases SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DIFFUSION AB The mobility of ions drifting in polar gases is explored both theoretically and experimentally. New experimental results are presented for (i) NO+ ions drifting in H2O (the reduced zero-field mobility K-0((0)) is 0.66+/-0.07 cm(2)V(-1)s(-1)), (ii) H3O+(H2O)(3) ions drifting in H2O (K-0((0))=0.43+/-0.06 cm(2)V(-1)s(-1)), and (iii) NO+(CH3COCH3)(n) ions (n=2,3) drifting in CH3COCH3 (K-0((0))=0.041+/-0.010 cm(2)V(-1)s(-1) for n=2 and K-0((0))=0.050+/-0.015 cm(2)V(-1)s(-1) for n=3). A number of theoretical models for ion mobilities in polar gases are described. The models are compared with the available experimental data and a reasonable agreement is obtained. For larger cluster ions the measured mobilities are considerably smaller than the calculated values. Some possible reasons for the discrepancies are discussed, including momentum transfer outside the capture cross section, dipole-dipole interactions, ligand exchange, inelastic collisions, and the validity of Blanc's law. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,NATL INST STAND & TECHNOL,JILA,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. RI de Gouw, Joost/A-9675-2008 OI de Gouw, Joost/0000-0002-0385-1826 NR 23 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 8 PY 1997 VL 106 IS 14 BP 5937 EP 5942 DI 10.1063/1.473609 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WR620 UT WOS:A1997WR62000014 ER PT J AU Poirier, GE AF Poirier, GE TI Mechanism of formation of Au vacancy islands in alkanethiol monolayers on Au(111) SO LANGMUIR LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; SELF-ASSEMBLED MONOLAYERS; ORGANIZED MOLECULAR ASSEMBLIES; SUPERLATTICE STRUCTURE; PROBE MICROSCOPY; EPITAXIAL-GROWTH; GOLD; SURFACE; FORCE; ADSORPTION AB Using an ultrahigh-vacuum scanning tunneling microscope we have discovered evidence for a novel mechanism by which Au vacancy islands form during assembly of alkanethiol monolayers on Au(111). Our results suggest a model whereby excess Au atoms are forced out of the surface layer by relaxation of the compressed herringbone reconstruction. This creates adatoms on, and vacancies in, the surface layer. On large terraces the vacancies nucleate into islands while the adatoms migrate and adsorb at ascending step edges. At saturation coverage of alkanethiols the surface exhibits approximate to 6% of a monolayer of vacancy islands. These results show that complex interactions between the assembling thiols and the herringbone reconstruction influence the mesoscopic aspects of the final monolayer surface. RP Poirier, GE (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 48 TC 275 Z9 275 U1 6 U2 36 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 2 PY 1997 VL 13 IS 7 BP 2019 EP 2026 DI 10.1021/la960777z PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA WR590 UT WOS:A1997WR59000025 ER PT J AU Siewert, TA Madigan, RB Quinn, TP AF Siewert, TA Madigan, RB Quinn, TP TI Sensors control gas metal arc welding SO ADVANCED MATERIALS & PROCESSES LA English DT Article AB Improved sensors electronically capture welding process data that provide the necessary information to build "intelligent" welding control systems. C1 Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA. RP Siewert, TA (reprint author), Natl Inst Stand & Technol, Div Mat Reliabil, 325 Broadway, Boulder, CO 80303 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 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 APR PY 1997 VL 151 IS 4 BP 23 EP 25 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA ZA403 UT WOS:000072360000002 ER PT J AU Chipanshi, AC Ripley, EA Lawford, RG AF Chipanshi, AC Ripley, EA Lawford, RG TI Early prediction of spring wheat yields in Saskatchewan from current and historical weather data using the CERES-Wheat model SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE spring wheat yields; current weather data; historical weather data; CERES-wheat model AB Wheat yields were simulated at three locations in Saskatchewan (Swift Current, Saskatoon and Melfort) using the CERES (crop estimation through resource and environment synthesis-wheat)-Wheat model. The simulations were made using climatic data of selected (base) years from the start of the growing season up to the prediction date; data for the remainder of the season (runout data) were taken from 1960-1990 climate records. Years corresponding to the first, second, and third quartile yield values were selected for the three study sites. Predicted yields were calculated as the means of the yields for the runout years, and were made at five growth stages: (i) emergence; (ii) terminal spikelet initiation; (iii) end of vegetative growth; (iv) start of ear growth; and (v) start of grain filling. Predictions using this method were found to agree well with measured data, suggesting that simulations made using a combination of historical climate records and current weather data as inputs provide good indications of yield. Use of these predictions would allow producers and those in agribusiness to choose alternative actions for minimizing losses when yield prospects are poor. (C) 1997 Elsevier Science B.V. C1 UNIV SASKATCHEWAN,DEPT CROP SCI & PLANT ECOL,SASKATOON,SK S7N 5A8,CANADA. NOAA,OGP,GCIP PROJECT OFF,SILVER SPRING,MD 20910. RP Chipanshi, AC (reprint author), UNIV SASKATCHEWAN,DEPT GEOG,9 CAMPUS DR,SASKATOON,SK S7N 5A5,CANADA. NR 34 TC 36 Z9 36 U1 4 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD APR PY 1997 VL 84 IS 3-4 BP 223 EP 232 DI 10.1016/S0168-1923(96)02363-5 PG 10 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA XH211 UT WOS:A1997XH21100003 ER PT J AU Duewer, DL Thomas, JB Kline, MC MacCrehan, WA Schaffer, R Sharpless, KE May, WE Crowell, JA AF Duewer, DL Thomas, JB Kline, MC MacCrehan, WA Schaffer, R Sharpless, KE May, WE Crowell, JA TI NIST/NCI micronutrients measurement quality assurance program: Measurement repeatabilities and reproducibilities for fat-soluble vitamin-related compounds in human sera SO ANALYTICAL CHEMISTRY LA English DT Article ID LIQUID-CHROMATOGRAPHIC SEPARATION; BETA-CAROTENE; ELECTROCHEMICAL DETECTION; ALPHA-TOCOPHEROL; RETINOL; ISOMERS AB The NIST/NCI Micronutrient Measurement Quality Assurance Program has conducted 33 interlaboratory comparison exercises for fat-soluble vitamin-related compounds in human sera over the past 12 years, Periodic reanalysis of lyophilized serum samples prepared from more than 70 different sera has enabled estimation of the short- and long-term measurement characteristics. Median- and interquartile-range-based statistics adequately estimate the distribution of results from laboratories that are in analytical control from total distributions that include a significant minority of outlier data, Short-term interlaboratory reproducibility standard deviations (SDs) are predictable functions of analyte concentration, with an asymptotic limit at low analyte concentration and a linear relationship at high concentrations, Long-term trends in the interlaboratory reproducibility can be estimated by standardizing the short-term SD at the observed analyte concentration to an expected SD at a given physiologically significant analyte concentration. The ''average'' laboratory's same-day analytical repeatability SD is about one-third of the estimated interlaboratory reproducibility; repeatability for longer periods between analyses is, on average, no better than the reproducibility. While a few exceptional laboratories have maintained excellent repeatability over the entire decade, long-term study measurements generated within a single laboratory are not generally more internally consistent than results from multiple laboratories, Enhanced and more consistently implemented intralaboratory quality control and quality assurance methods are required to further improve and maintain interlaboratory measurement comparability. C1 NCI,CHEMOPREVENT BRANCH,DIV CANC PREVENT & CONTROL,NIH,BETHESDA,MD 20892. RP Duewer, DL (reprint author), NATL INST STAND & TECHNOL,DIV ANALYT CHEM,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. RI Duewer, David/B-7410-2008 NR 25 TC 19 Z9 19 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD APR 1 PY 1997 VL 69 IS 7 BP 1406 EP 1413 DI 10.1021/ac9607727 PG 8 WC Chemistry, Analytical SC Chemistry GA WQ777 UT WOS:A1997WQ77700028 PM 9105181 ER PT J AU Camps, J Massons, J Soler, MR Nickerson, EC AF Camps, J Massons, J Soler, MR Nickerson, EC TI Pollutant transport in coastal areas with and without background wind SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article ID SEA-BREEZE; MODEL; VEGETATION; FLOW; CIRCULATIONS; MICROPHYSICS; SIMULATIONS; DISPERSION; DIFFUSION; TERRAIN AB A three-dimensional meteorological model and a Lagrangian particle dispersion model are used to study the effects of a uniform large-scale wind on the dispersion of a non-reactive pollutant in a coastal region with complex terrain. Simulations are carried out both with and without a background wind. A comparison between model results and measured data (wind and pollutant concentrations) indicates that the coupled model system provides a useful mechanism for analyzing pollutant dispersion in coastal regions. C1 UNIV ROVIRA & VIRGILI,APPL PHYS LAB,TARRAGONA,SPAIN. UNIV BARCELONA,DEPT ASTRON & METEOROL,BARCELONA,SPAIN. NOAA,FORECAST SYST LAB,BOULDER,CO. RI Soler, Maria Rosa/H-9224-2015; OI Soler, Maria Rosa/0000-0003-3830-3202; massons, jaume/0000-0003-4325-6084 NR 24 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD APR PY 1997 VL 15 IS 4 BP 476 EP 486 DI 10.1007/s00585-997-0476-5 PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA WX436 UT WOS:A1997WX43600012 ER PT J AU Zimmerman, BE Colle, R AF Zimmerman, BE Colle, R TI Comparison of the French and US National H-3 (tritiated H2O) standards by 4 pi beta liquid scintillation spectrometry SO APPLIED RADIATION AND ISOTOPES LA English DT Article ID EFFICIENCY AB Radioactivity standards of tritiated water ((H2O)-H-3)-disseminated by the Laboratoire Primaire des Rayonnements Ionisants (LPRI) and the National Institute of Standards and Technology (NIST), the national radionuclidic metrology and standardization laboratories of France and U.S.A., respectively-have been intercompared by liquid scintillation (LS) spectrometry. The ratio of the certified massic activities for the two standards was compared to that obtained from direct measurements on matched sets of LS cocktails prepared from the standards. Seven experimental trials (involving a total of 21 counting sources for each standard) were performed for the comparison. The trials were performed under a wide range of experimental conditions, including use of two different LS spectrometers and three series of LS cocktail compositions (with systematically varied) H-3 detection efficiencies). The results exhibited an apparent mean disagreement between standards of < 0.4% on a relative basis. For contrast, the relative combined standard uncertainty on the massic activity ratio for the two standards, as obtained from their respective certified uncertainty assessments, is about 0.7%. (C) 1997 Published by Elsevier Science Ltd. RP Zimmerman, BE (reprint author), NIST,PHYS LAB,GAITHERSBURG,MD 20899, USA. NR 20 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD APR PY 1997 VL 48 IS 4 BP 521 EP 526 DI 10.1016/S0969-8043(96)00270-9 PG 6 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA WR455 UT WOS:A1997WR45500016 PM 9106992 ER PT J AU Zhang, ZM Zhu, CJ Hanssen, LM AF Zhang, ZM Zhu, CJ Hanssen, LM TI Absolute detector calibration applied to nonlinearity error correction in FT-IR measurements SO APPLIED SPECTROSCOPY LA English DT Article; Proceedings Paper CT 2nd International Symposium on Advanced Infrared Spectroscopy, AIRS II CY JUN, 1996 CL DUKE UNIV, DURHAM, NC SP Bio Rad Digilab Div, Bruker Spectrospin, Bruker Optics Div, Nicolet Instruments, Duke Univ, Coblenz Soc HO DUKE UNIV DE detector responsivity calibration; FT-IR spectrometer; nonlinearity correction; transmittance AB A method for correcting the effects of detector nonlinearity in Fourier transform infrared (FT-IR) spectrometers has been developed, The method incorporates directly measured results, No adjustable parameters are used. The absolute responsivity of two HgCdTe (MCT) detector/preamplifier systems as a function of incident photon flux was calibrated against a transfer-standard Ge detector with a diode laser source at 1.32 mu m With the use of the MCT detector, preliminary measurements were made on an FT-IR spectrometer in both the near- and mid-infrared spectral regions, The measured nonlinear interferograms were corrected by using the detector response curve and the measured de output of the preamplifier. Ln the resultant spectra, the nonzero values in the spectral region below the detector cutoff frequency mere significantly reduced when the corrected interferograms were used, The transmittance spectra of a Si wafer and a neutral-density filter mere measured with an MCT detector and a deuterated triglycine sulfate (DTGS) detector, Errors in transmittance caused hy detector nonlinearity were greatly reduced with the use of the correction method. C1 UNIV IDAHO,DEPT CHEM,MOSCOW,ID 83844. NATL INST STAND & TECHNOL,OPT TECHNOL DIV,GAITHERSBURG,MD 20899. RP Zhang, ZM (reprint author), UNIV FLORIDA,DEPT MECH ENGN,GAINESVILLE,FL 32611, USA. NR 12 TC 17 Z9 17 U1 2 U2 6 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD APR PY 1997 VL 51 IS 4 BP 576 EP 579 DI 10.1366/0003702971940639 PG 4 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA WX756 UT WOS:A1997WX75600024 ER PT J AU Meador, JP AF Meador, JP TI Comparative toxicokinetics of tributyltin in five marine species and its utility in predicting bioaccumulation and acute toxicity SO AQUATIC TOXICOLOGY LA English DT Article DE tributyltin; toxicokinetics; species differences; bioaccumulation; LC50; LR50 ID ANTIFOULING PAINTS; NUCELLA-LAPILLUS; INFAUNAL AMPHIPODS; DOG-WHELK; SEDIMENT; TBT; CHEMICALS; TISSUE; FISH; BIOAVAILABILITY AB The acute toxic response (LC50), bioconcentration factor (BCF), lethal tissue residue (LR50), uptake clearance constant (k(1)), and elimination rate constant (k(2)) for tributyltin (TBT) were examined and compared in four marine invertebrate and one marine fish species. The toxic response and BCFs were vastly different among the species when exposed to the dissolved compound, which was reflected in their unequal uptake clearance and elimination rate constants. Based on the dual-rate constant approach for a one compartment, first-order kinetic model (1CFOK), predicted values for both the acute toxic response and BCF based on these toxicokinetic constants were matched closely by observed values. Additionally, a strong correlation between the LC50 and BCF was found, which was expected based on their relationship to the balance between uptake and elimination and a consistent LR50 (lethal residue causing 50% mortality) among species. Predictions were made about the time to steady-state tissue concentrations with k(2) values and how this would affect the results of the standard 10 day toxicity bioassay. Because acute TBT toxicity occurs at tissue concentrations 100 times lower than compounds exhibiting a narcosis mode of action, tributyltin is very toxic at low environmental concentrations, especially to organisms that have high uptake clearance and low elimination rate constants. Making predictions about toxicity based on uptake clearance and elimination rate constants in conjunction with the critical body residue will be helpful when choosing sensitive organisms for determining water and sediment quality criteria. RP Meador, JP (reprint author), NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,ENVIRONM CONSERVAT DIV,2725 MONTLAKE BLVD E,SEATTLE,WA 98112, USA. NR 53 TC 43 Z9 47 U1 0 U2 14 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 1997 VL 37 IS 4 BP 307 EP 326 DI 10.1016/S0166-445X(96)00827-2 PG 20 WC Marine & Freshwater Biology; Toxicology SC Marine & Freshwater Biology; Toxicology GA XC780 UT WOS:A1997XC78000004 ER PT J AU Zweibel, EG Brandenburg, A AF Zweibel, EG Brandenburg, A TI Current sheet formation in the interstellar medium SO ASTROPHYSICAL JOURNAL LA English DT Article DE diffusion; ISM, magnetic fields; MHD ID AMBIPOLAR DIFFUSION; MOLECULAR CLOUDS; MAGNETIC-FIELDS AB There is phenomenological evidence that magnetic reconnection operates in the interstellar medium, and magnetic reconnection is also necessary for the operation of a galactic dynamo. The extremely long ohmic diffusion times of magnetic fields in typical interstellar structures suggest that reconnection occurs in two stages, with thin current layers that have relatively short resistive decay times forming by magnetohydrodynamical processes first, followed by reconnection of the fields in the layers. We propose that ambipolar drift can lead to the formation of these thin sheets in weakly ionized interstellar gas and can delineate the parameter regime in which this occurs by means of a numerical model: we find that the magnetic field cannot be too large and the medium cannot be too diffusive. Both limits are imposed by the requirement that the field be wound up about 1 time by the eddy. C1 UNIV COLORADO,BOULDER,CO 80309. UNIV NEWCASTLE,DEPT MATH & STAT,CALLAGHAN,NSW 2308,AUSTRALIA. RP Zweibel, EG (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. RI Brandenburg, Axel/I-6668-2013 OI Brandenburg, Axel/0000-0002-7304-021X NR 24 TC 60 Z9 60 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1997 VL 478 IS 2 BP 563 EP 568 DI 10.1086/303824 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WQ321 UT WOS:A1997WQ32100014 ER PT J AU Kogan, FN AF Kogan, FN TI Global drought watch from space SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID HIGH-RESOLUTION RADIOMETER; NATURAL DISASTER REDUCTION; AVHRR DATA; DATA SETS; VEGETATION; CALIBRATION; CHANNELS; PRODUCT AB Drought is the most damaging environmental phenomenon. During 1967-91, droughts affected 50% of the 2.8 billion people who suffered from weather-related disasters. Since droughts cover large areas, it is difficult to monitor them using conventional systems. In recent years the National Oceanic and Atmospheric Administration has designed a new Advanced Very High Resolution Radiometer- (AVHRR) based Vegetation Condition Index (VCI) and Temperature Condition Index (TCI), which have been useful in detecting and monitoring large area, drought-related vegetation stress. The VCI was derived from the Normalized Difference Vegetation Index (NDVI), which is the ratio of the difference between AVHRR-measured near-infrared and visible reflectance to their sum. The TCI was derived from the 10.3-11.3-mu m AVHRR-measured radiances, converted to brightness temperature CBT). Algorithms were developed to reduce the noise and to adjust NDVI and BT for land surface nonhomogeneity. The VCI and TCI are used to determine the water- and temperature-related vegetation stress occuring during drought. This paper provides the principles of these indices, describes data processing, and gives examples of VCI-TCI applications in different ecological environments of the world. The results presented here are the first attempt to use both NDVI and thermal channels on a large area with very diversified ecological resources. The application of VCI and TCI are illustrated and validated by in situ measurements. These indices were also used for assessment of drought impact on regional agricultural production in South America, Africa, Asia, North America, and Europe. For this purpose, the average VCI-TCI values for a given region and for each week of the growing season were calculated and compared with yields of agricultural crops. The results showed a very strong correlation between these indices and yield, particularly during the critical periods of crop growth. RP Kogan, FN (reprint author), NOAA,NESDIS,CTR SCI,ROOM 712,5200 AUTH RD,CAMP SPRINGS,MD 20746, USA. RI Kogan, Felix/F-5600-2010 OI Kogan, Felix/0000-0001-8216-900X NR 59 TC 268 Z9 287 U1 8 U2 41 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 1997 VL 78 IS 4 BP 621 EP 636 DI 10.1175/1520-0477(1997)078<0621:GDWFS>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XA634 UT WOS:A1997XA63400001 ER PT J AU Crescenti, GH AF Crescenti, GH TI A look back on two decades of Doppler sodar comparison studies SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID TEMPERATURE STRUCTURE PARAMETER; ATMOSPHERIC BOUNDARY-LAYER; AIR-POLLUTION METEOROLOGY; ACOUSTIC SOUNDERS; HEAT-FLUX; FLOWS; ANEMOMETERS; ANTARCTICA; PROFILES; DYNAMICS AB This paper is a compilation of the results obtained from various Doppler sodar comparison experiments conducted over the last 20 years. These studies have attempted to quantify the uncertainties in sodar-derived values of the horizontal wind speed, wind direction, standard deviation of the vertical wind speed sigma(w), and standard deviation of the horizontal wind direction sigma(theta). Doppler sodar configurations examined in these studies included bistatic, monostatic, and phased array. In most cases, reference measurements used for comparison were made by tower-based in situ sensors. Many investigators have used simple linear regressions and other statistical measures such as the correlation coefficient, bias (mean difference), comparability (root-mean-square difference), and precision (standard deviation) in an attempt to quantify those errors. The sodar-derived wind speed and wind direction are highly correlated against reference measurements (similar to 0.92) with a precision of 1.06 m s(-1) and 21.5 degrees, respectively, for the entire dataset. Correlations of sodar-derived values of sigma(w) were not quite as good (similar to 0.81) with an average precision of 0.18 m s(-1). Past studies have shown that sigma(w) accuracies vary significantly from day (convective conditions) to night (stable conditions). Very few data values were available for sigma(theta), which had a poor correlation of 0.57 and a precision of 10.7 degrees. The conclusions from many of these studies have shown that Doppler sodars can accurately obtain the mean wind speed and wind direction. Values of sigma(w) have larger uncertainties, while estimates of sigma(theta), have errors that are considered unacceptable for any practical use. Much of the observed scatter in sodar wind measurements can be attributed to a number of factors. These include, but are not limited to, instrument configuration, spatiotemporal variability, noise, and processing techniques. C1 NOAA,ATMOSPHER SCI MODELING DIV,AIR RESOURCES LAB,RES TRIANGLE PK,NC. NR 88 TC 33 Z9 34 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 1997 VL 78 IS 4 BP 651 EP 673 DI 10.1175/1520-0477(1997)078<0651:ALBOTD>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XA634 UT WOS:A1997XA63400003 ER PT J AU Gould, P Ostrom, P Walker, W AF Gould, P Ostrom, P Walker, W TI Trophic relationships of albatrosses associated with squid and large-mesh drift-net fisheries in the North Pacific Ocean SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID STABLE ISOTOPES; DIOMEDEA-MELANOPHRIS; SEABIRDS; CARBON; FRACTIONATION; TURNOVER; NITROGEN; TISSUES; ECOLOGY; ISLANDS AB The diets of Laysan (Diomedea immutabilis) and black-footed albatrosses (D. nigripes) killed in squid and large-mesh drift nets in the transitional zone of the North Pacific Ocean were investigated by examining the contents of the digestive tracts and determining delta(13)C and delta(15)N values in breast-muscle tissue. The results show that (i) the combined prey of the two species of albatross consists of over 46 species of marine organisms including coelenterates, arthropods, mollusks, fish, and marine mammals; (ii) both species supplement their traditional diets with food made available by commercial fishing operations (e.g., net-caught squid and offal); (iii) while obtained from drift nets, diets of nonbreeding Laysan and black-footed albatrosses are dominated by neon flying squid (Ommastrephes bartrami); (iv) in the absence of drift-net-related food, Laysan albatrosses feed most heavily on fish and black-footed albatrosses feed most heavily on squid; and (v) based on delta(15)N values, nonbreeding adult Laysan albatrosses from the transitional zone of the North Pacific Ocean and Laysan albatross nestlings fed by adults from Midway Island in the subtropical Pacific feed at one trophic level and one-third of a trophic level lower than black-footed albatrosses, respectively. C1 MICHIGAN STATE UNIV,DEPT GEOL SCI,E LANSING,MI 48824. NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,NATL MARINE MAMMAL LAB,SEATTLE,WA 98115. RP Gould, P (reprint author), NATL BIOL SERV,ALASKA SCI CTR,1011 E TUDOR RD,ANCHORAGE,AK 99503, USA. NR 41 TC 37 Z9 38 U1 0 U2 16 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD APR PY 1997 VL 75 IS 4 BP 549 EP 562 DI 10.1139/z97-068 PG 14 WC Zoology SC Zoology GA XB777 UT WOS:A1997XB77700006 ER PT J AU Garboczi, EJ AF Garboczi, EJ TI Stress, displacement, and expansive cracking around a single spherical aggregate under different expansive conditions SO CEMENT AND CONCRETE RESEARCH LA English DT Article AB There seems to have been some confusion in recent years regarding the stress and displacements induced in a concrete material when either the matrix, the aggregate, or a shell around the aggregate is expansive. The case of a single spherical aggregate, surrounded by a single shell of arbitrary thickness, all of which are embedded in a matrix, can be solved exactly for any combination of elastic moduli and expansive strains. Solutions of this problem under various choices of parameters are used to illustrate the features of stress, displacement, and expansive cracking that are possible. These solutions can then be used to help better understand the features seen under the microscope in concretes that have been damaged by different expansive forces. (C) 1997 Elsevier Science Ltd RP Garboczi, EJ (reprint author), NATL INST STAND & TECHNOL,BLDG MAT DIV,226-B350,GAITHERSBURG,MD 20899, USA. NR 13 TC 20 Z9 20 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0008-8846 J9 CEMENT CONCRETE RES JI Cem. Concr. Res. PD APR PY 1997 VL 27 IS 4 BP 495 EP 500 DI 10.1016/S0008-8846(97)00029-X PG 6 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA WZ181 UT WOS:A1997WZ18100003 ER PT J AU Kuhn, DR AF Kuhn, DR TI Sources of failure in the Public Switched Telephone Network SO COMPUTER LA English DT Article AB The US portion of possibly the largest distributed system in the world, the PSTN is also among the most reliable. But why? The author studied outage records maintained by the US Federal Communications Commission to find out. The FCC data tallies the number and duration of outages as well as the number of customers affected. Although such data are interesting as separate entities, it became clear that a meaningful comparison required their combination. The author used the concept of customer minutes-the number of affected customers multiplied by the length of the outage in minutes-to provide this comparison. The author also used a classification technique that is general enough to compare with other large distributed systems. Major categories of failure include human error, acts of nature, hardware and software failures, overloads, and vandalism. Analysis of the FCC records shows that although human error causes almost half the outages, such outages are relatively short. Overloads-outages accepted as a cost-performance trade-off for the telephone system-affect the most customers for the most minutes. The capability for human intervention is one key to the PSTN's reliability. This system also achieves an excellent tradeoff between loose coupling and interaction simplicity, showing that the balance between these characteristics is an important consideration in any distributed system design. Telephone switch manufacturers also produce extremely reliable software. RP Kuhn, DR (reprint author), NATL INST STAND & TECHNOL,SOFTWARE QUAL GRP,GAITHERSBURG,MD 20899, USA. NR 8 TC 37 Z9 37 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 SN 0018-9162 J9 COMPUTER JI Computer PD APR PY 1997 VL 30 IS 4 BP 31 EP & DI 10.1109/2.585151 PG 7 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA WR934 UT WOS:A1997WR93400029 ER PT J AU Klein, R AF Klein, R TI Dissolution of zirconium in nitric-hydrofluoric acid mixtures SO CORROSION LA English DT Article DE dissolution; enthalpy; hydrofluoric acid; hydrogen evolution; nitric acid; zirconium ID STANDARD AB There is a linear relationship between the enthalpy of solution of zirconium in nitric-hydrofluoric acid (HNO3-HF) mixtures and the molar HNO3/HF ratio (R) from R = 0 to 0.55. At R = 0.55, the enthalpy attains a maximum value and remains constant up to at least R = 8. There is a corresponding behavior in a reverse order with regard to hydrogen evolution which is linear with R from a maximum at R = 0 to zero at R greater than or equal to 0.55. Regardless of composition of the mixed acids, the zirconium-containing product is the same. A mechanism was proposed to account for the relationship of solution enthalpy and hydrogen evolution with the acid ratio. The rate of dissolution of zirconium in HF alone displayed a strong dependence on concentration > 0.5 mol/L. II was not sensitive to addition of HNO3, but there was a slowing of the rate for HNO3 concentrations > 0.4 mol/L. RP Klein, R (reprint author), NATL INST STAND & TECHNOL,US DEPT COMMERCE,CHEM SCI & TECHNOL LAB,DIV CHEM KINET & THERMODYNAM,GAITHERSBURG,MD 20899, USA. NR 15 TC 4 Z9 4 U1 0 U2 3 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 SN 0010-9312 J9 CORROSION JI Corrosion PD APR PY 1997 VL 53 IS 4 BP 327 EP 332 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA XU785 UT WOS:A1997XU78500009 ER PT J AU Sturrock, CP Bogaerts, WF AF Sturrock, CP Bogaerts, WF TI Empirical learning investigations of the stress corrosion cracking of austenitic stainless steels in high-temperature aqueous environments SO CORROSION LA English DT Article DE aqueous corrosion; decision tree; expert system; fuzzy logic; linear discriminant; nearest neighbor; polynomial network; stainless steel; stress corrosion cracking AB A collection of data documenting the stress corrosion cracking (SCC) behavior of austenitic stainless steels (SS) in high-temperature aqueous environments was investigated using empirical learning techniques. Computer-based empirical learning systems based on classical and nonparametric statistics, connectionist models, machine learning methods, and fuzzy logic are described. An original method for inducing fuzzy rules from input-output data is presented. Performance comparisons of the various approaches are summarized, along with the relative intelligibility of the outputs. In both respects, the decision-tree approach was found to perform very well on the problem investigated. C1 KATHOLIEKE UNIV LEUVEN,DEPT MTM,B-3001 LOUVAIN,BELGIUM. RP Sturrock, CP (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 17 TC 5 Z9 6 U1 0 U2 3 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 SN 0010-9312 J9 CORROSION JI Corrosion PD APR PY 1997 VL 53 IS 4 BP 333 EP 343 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA XU785 UT WOS:A1997XU78500010 ER PT J AU Doney, SC Jenkins, WJ Bullister, JL AF Doney, SC Jenkins, WJ Bullister, JL TI A comparison of ocean tracer dating techniques on a meridional section in the eastern North Atlantic SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID GYRE VENTILATION; TRITIUM; HE-3; RATES; WATER; CHLOROFLUOROCARBON-11; DISTRIBUTIONS; THERMOCLINE; CIRCULATION; SEAWATER AB Tritium and excess He-3 data from a 1988 meridional section in the eastern North Atlantic are presented and related to hydrographic data for the region. The computed tritium-He-3 ventilation ages are well correlated over a wide range of water masses with an independent tracer age estimate from a contemporaneous chlorofluorocarbon CFC-12 data set, with residuals only slightly greater than those expected from sampling error alone. The tritium-He-3 ages are slightly younger (similar to 1 year) than the CFC-12 ages in recently ventilated water, and the disparity between the two tracer ages increases sharply for ages approaching the elapsed period since the bomb-tritium input in the early 1960s. The overall features of the tracer age-age curve are captured by a simple 2-D gyre circulation model and are related to the timescales of the transient for each tracer and the pre-anthropogenic and primordial backgrounds of He-3. Regions of anomalously low tritium-He-3 age relative to the overall section tracer age-age curve are observed near the tropical-subtropical transition and in the deep thermocline in the southern part of the subtropical gyre. These areas contain steep tracer gradients on isopycnal surfaces and elevated non-linear tracer age mixing effects, based on diagnostic calculations. (C) 1997 EIsevier Science Ltd. C1 WOODS HOLE OCEANOG INST, MARINE CHEM & GEOCHEM DEPT, WOODS HOLE, MA 02543 USA. NOAA, PACIFIC MARINE ENVIRONM LAB, SEATTLE, WA 98115 USA. RP Doney, SC (reprint author), NATL CTR ATMOSPHER RES, CLIMATE & GLOBAL DYNAM DIV, POB 3000, BOULDER, CO 80307 USA. RI Doney, Scott/F-9247-2010 OI Doney, Scott/0000-0002-3683-2437 NR 46 TC 67 Z9 68 U1 4 U2 8 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 1997 VL 44 IS 4 BP 603 EP 626 DI 10.1016/S0967-0637(96)00105-7 PG 24 WC Oceanography SC Oceanography GA XA977 UT WOS:A1997XA97700005 ER PT J AU Edgington, DN Robbins, JA Colman, SM Orlandini, KA Gustin, MP Klump, JV Granina, LZ AF Edgington, DN Robbins, JA Colman, SM Orlandini, KA Gustin, MP Klump, JV Granina, LZ TI Comment on ''Uranium-series disequilibrium, sedimentation, diatom frustules, and paleoclimate change in Lake Baikal'' - Reply SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Editorial Material ID EQUILIBRIA; CARBON C1 NOAA, GREAT LAKES ENVIRONM RES LAB, ANN ARBOR, MI 48105 USA. US GEOL SURVEY, WOODS HOLE, MA 02543 USA. ARGONNE NATL LAB, DIV ENVIRONM RES, ARGONNE, IL 60439 USA. RUSSIAN ACAD SCI, INST LIMNOL, SIBERIAN DIV, IRKUTSK 664003, RUSSIA. RP UNIV WISCONSIN, CTR GREAT LAKES STUDIES, MILWAUKEE, WI 53204 USA. NR 17 TC 11 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X EI 1385-013X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD APR PY 1997 VL 148 IS 1-2 BP 399 EP 404 DI 10.1016/S0012-821X(97)00033-2 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XC561 UT WOS:A1997XC56100030 ER PT J AU Driscoll, SK Harkey, GA Landrum, PF AF Driscoll, SK Harkey, GA Landrum, PF TI Accumulation and toxicokinetics of fluoranthene in sediment bioassays with freshwater amphipods SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE fluoranthene; sediment; amphipods; toxicokinetics; accumulation ID POLYCYCLIC AROMATIC-HYDROCARBONS; EQUILIBRIUM-PARTITIONING THEORY; HYALELLA-AZTECA; ORGANIC CONTAMINANTS; QUALITY CRITERIA; PONTOPOREIA-HOYI; TOXICITY TESTS; BIOAVAILABILITY; DIPOREIA; WATER AB Two freshwater amphipods, Hyalella azteca and Diporeia sp., were exposed to sediment spiked with radiolabeled fluoranthene at nominal concentrations of 0.1 (trace) to 1,270 nmal fluoranthene/g dry weight. In two experiments, uptake kinetics and mortality were determined over 30-d exposures. Concentrations of fluoranthene in sediment and pore water were also measured. Mean survival of H, azteca was generally high, greater than 90% after 10 or 16 d, and greater than 74% after 30 d. Mean survival was lower for Diporeia, 14% after a 30-d exposure to the highest sediment concentration in experiment I, and 53% in experiment 2. Tissue concentrations in Diporeia were as high as 2 to 4 mu mol/g wet weight, a body burden that could be expected to result in death by narcosis. Hyalella azteca did not typically accumulate more than 1 mu mol/g wet weight, which is consistent with the lower observed mortality. Apparent steady-state biota-sediment accumulation factors (BSAFs, lipid- and organic-carbon-normalized) for sediment concentrations other than trace level tended to be higher for Diporeia (0.345-0.818) than for H, azteca (0.161-0.612). The BSAFs for trace levels tended to be lower for both species (0.045-0.436) in comparison La higher sediment concentrations. For both organisms, the internal concentration based on body residue was a more reliable indicator of toxicity than were equilibrium partitioning predictions. C1 NOAA, GREAT LAKES ENVIRONM RES LAB, ANN ARBOR, MI 48105 USA. NR 45 TC 34 Z9 35 U1 0 U2 5 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0730-7268 EI 1552-8618 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD APR PY 1997 VL 16 IS 4 BP 742 EP 753 DI 10.1897/1551-5028(1997)016<0742:AATOFI>2.3.CO;2 PG 12 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA WU832 UT WOS:A1997WU83200019 ER PT J AU Driscoll, SK Landrum, PF Tigue, E AF Driscoll, SK Landrum, PF Tigue, E TI Accumulation and toxicokinetics of fluoranthene in water-only exposures with freshwater amphipods SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE fluoranthene; amphipods; toxicokinetics; water; critical body burden ID POLYCYCLIC AROMATIC-HYDROCARBONS; LIPOPHILIC CHEMICALS; ORGANIC XENOBIOTICS; AQUATIC ORGANISMS; PONTOPOREIA-HOYI; LIPID-CONTENT; DIPOREIA SP; SEDIMENT; TOXICITY; BIOAVAILABILITY AB Two 10-d water-only toxicity tests with radiolabeled fluoranthene were conducted with two species of freshwater amphipods, Hyalella azteca and Diporeia sp. For H. azteca, 10-d median lethal concentrations were 564 nmol/L and 481 nmol/L. Tentative median lethal doses, determined from the regressions of body burden of remaining live H, azteca versus survival, were 5.6 and 3.6 mmol fluoranthene/kg wet weight tissue. Diporeia appeared to be less sensitive, because survival in Diporeia was greater than 84% after 10-d exposures. Elimination rates determined for Diporeia, ranging from 0.0011 to 0.0042/h (half-lives of 7-26 d), were much slower than rates determined for H. azteca of 0,128 to 0.188/h (half-lives of 4-6 h). Faster elimination in H, azteca may be related to its greater ability to metabolize fluoranthene. For H. azteca, an average of 17% of its body burden was present as metabolites after 24 h of exposure to radiolabeled fluoranthene, as compared to 5% for Diporeia. For Diporeia, exposure to various water concentrations of fluoranthene for various lengths of time resulted in declines in the conditional uptake clearance rates (mi water cleared/g wet weight tissue/h). A similar, although less dramatic trend was observed for conditional uptake clearance rates in H, azteca. C1 NOAA, GREAT LAKES ENVIRONM RES LAB, ANN ARBOR, MI 48105 USA. NR 35 TC 37 Z9 38 U1 0 U2 4 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0730-7268 EI 1552-8618 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD APR PY 1997 VL 16 IS 4 BP 754 EP 761 DI 10.1897/1551-5028(1997)016<0754:AATOFI>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA WU832 UT WOS:A1997WU83200020 ER PT J AU Harkey, GA Driscoll, SK Landrum, PF AF Harkey, GA Driscoll, SK Landrum, PF TI Effect of feeding in 30-day bioaccumulation assays using Hyalella azteca in fluoranthene-dosed sediment SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE sediment; bioaccumulation; fluoranthene; feeding; Hyalella azteca ID POLYCYCLIC AROMATIC-HYDROCARBONS; AMPHIPOD PONTOPOREIA-HOYI; ORGANIC CONTAMINANTS; TOXICITY TESTS; WHOLE-SEDIMENT; BIOAVAILABILITY; WATER; DIPOREIA; TOXICOKINETICS; BIOASSAYS AB Current protocols for conducting freshwater sediment bioaccumulation tests recommend that food not be added to exposures, whereas toxicity tests require food addition. To determine effects of adding food on exposure, 30-d sediment exposures were conducted with Hyalella azteca to sediment dosed with four fluoranthene concentrations (trace level to 897 nmol/g dry weight), Accumulation was significantly greater in fed versus nonfed animals al all dose levels after 96 h of exposure and continued to be greater after 30 d in the low dose levels. At sediment concentrations above 478 nmol/g dry weight, survival of unfed animals dropped to 34% after 30 d. After 30 d of exposure, growth and reproduction were observed in fed animals exposed to sediment concentrations 20 to 90 times the expected median lethal concentration (LC50) values for fluoranthene in sediment, according to 10-d studies reported in the literature using sediment with comparable organic carbon concentrations. Samples of sediment in exposure beakers taken from the sediment-water interface (flocculant layer) and 1 to 2 cm below the interface had large differences in fluoranthene and organic carbon concentrations. The concentration of fluoranthene was 2 to IO times greater in the flocculant layer, the area inhabited by H. azteca, compared to the deeper sediment. These data raise questions concerning the interpretation of standard toxicity and bioaccumulation tests when food is routinely added. C1 NOAA,GREAT LAKES ENVIRONM RES LAB,ANN ARBOR,MI 48105. NR 24 TC 19 Z9 19 U1 0 U2 1 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD APR PY 1997 VL 16 IS 4 BP 762 EP 769 DI 10.1897/1551-5028(1997)016<0762:EOFIDB>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA WU832 UT WOS:A1997WU83200021 ER PT J AU Sheridan, P AF Sheridan, P TI Benthos of adjacent mangrove, seagrass and non-vegetated habitats in Rookery Bay, Florida, USA SO ESTUARINE COASTAL AND SHELF SCIENCE LA English DT Article DE benthos; mangroves; seagrass; mud; habitats; estuaries; Florida ID NORTHWESTERN AUSTRALIA; PLANT STRUCTURE; COMMUNITIES; ABUNDANCE; MEIOFAUNA; ESTUARY; COMPLEXITY; ECOSYSTEM; PREDATION; EELGRASS AB Benthic faunal abundances and biomasses in adjacent mangrove, seagrass and non-vegetated mud habitats were compared in Rookery Bay, Florida, U.S.A. Although all habitats were intertidal, mangroves received the shortest duration of flooding, and non-vegetated mud received the longest. Replicate cores were taken at high tide in each habitat in July, September and December 1988, and in April 1989. Seagrass substrates were low organic content sands, whereas mangrove and non-vegetated substrates were high organic content sandy clays. Over 300 taxa were recorded, most of them relatively rare, and only 32 taxa were considered dominant (averaging greater than or equal to 636 individuals m(-2) or five core(-1) in any habitat at a given time). Seagrass and non-vegetated mud faunas were more diverse than those of mangrove substrates. Total densities were always higher in red mangrove (Rhizophora mangle) pear than elsewhere, averaging 22 591 to 52 914 individuals m(-2). Densities in mixed seagrasses ranged between 6347 and 23 545 individuals m(-2), while those in non-vegetated mud ranged between 3611 and 22 465 individuals m(-2). Biomasses, however, were always higher in either seagrasses (15.7-87.4 g wet weight m(-2)) or non-vegetated mud (11.9-26.2 g m(-2)) than in mangroves (3.6-8.2 g m(-2)). Tanaids and annelids were the numerical dominants, reaching maximum densities of 35 127 and 31 388 m(-2) respectively, in mangroves. Annelids were also the dominant biomass in most habitats each month. Variation in densities of most of the 32 dominant taxa were related to habitat not time. Each habitat harboured four to eight taxa that were significantly more abundant there than in alternate habitats. Feeding guild analysis indicated few differences among habitats, as surface deposit feeders and carnivores were predominant. Red mangrove appear capable of functioning in a manner similar to intertidal marsh habitats by providing high densities of small prey items for mobile consumers able to exploit the intertidal zone during high tide. Experimental verification of this function remains necessary. (C) 1997 Academic Press Limited. RP Sheridan, P (reprint author), US DEPT COMMERCE,NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,4700 AVE U,GALVESTON,TX 77551, USA. NR 59 TC 66 Z9 70 U1 2 U2 14 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0272-7714 J9 ESTUAR COAST SHELF S JI Estuar. Coast. Shelf Sci. PD APR PY 1997 VL 44 IS 4 BP 455 EP 469 DI 10.1006/ecss.1996.0125 PG 15 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA WW945 UT WOS:A1997WW94500006 ER PT J AU Cooper, LY AF Cooper, LY TI VENTCF2: An algorithm and associated FORTRAN 77 subroutine for calculating flow through a horizontal ceiling/floor vent in a zone-type compartment fire model SO FIRE SAFETY JOURNAL LA English DT Article AB An algorithm and associated FORTRAN 77 subroutine, called VENTCF2, for calculating the effects on two-layer compartment fire environments of the quasi-steady flow through a circular, shallow (i.e. small ratio of depth-to-diameter), horizontal vent connecting two spaces is presented. The two spaces can be either two inside rooms of a multi-room facility or one inside room and the outside ambient environment local to the vent. The flow is determined by consideration of standard orifice-type flows driven by cross-vent pressure differences and, when appropriate, the combined pressure- and buoyancy-driven flows which occur when the density configuration across the vent is unstable, i.e. a relatively cool, dense gas in the upper space overlays a less dense gas in the lower space. The algorithm calculates rates of flow exchange between the two spaces based on previously reported model equations. Characteristics of geometry and the instantaneous environments of the two spaces are assumed to be known and specified as inputs. Outputs calculated are the rates and top space from the bottom space and/or as it enters the bottom space from the top space. Rates of mass, enthalpy and products of combustion extracted by the vent flows from upper and lower layers of inside room environments and from outside ambient spaces are determined explicitly. VENTCF2 is an advanced version of the algorithm/subroutine. VENTCF in that it includes an improved theoretical and experimental basis. The subroutine is completely modular and it is suitable for general use in two-layer, multi-room, zone-type fire model computer codes. It has been tested numerically over a wide range of input variables and the results of some of these tests are described. Published by Elsevier Science Ltd. RP Cooper, LY (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 20 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0379-7112 J9 FIRE SAFETY J JI Fire Saf. J. PD APR PY 1997 VL 28 IS 3 BP 253 EP 287 DI 10.1016/S0379-7112(96)00072-0 PG 35 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA XF909 UT WOS:A1997XF90900005 ER PT J AU Steimle, FW Meier, MH AF Steimle, FW Meier, MH TI What information do artificial reef managers really want from fishery science? SO FISHERIES LA English DT Article RP Steimle, FW (reprint author), NATL MARINE FISHERIES SERV,NE FISHERIES SCI CTR,JJ HOWARD MARINE SCI LAB,HIGHLANDS,NJ 07732, USA. NR 3 TC 11 Z9 13 U1 0 U2 0 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0363-2415 J9 FISHERIES JI Fisheries PD APR PY 1997 VL 22 IS 4 BP 6 EP 8 PG 3 WC Fisheries SC Fisheries GA WQ998 UT WOS:A1997WQ99800002 ER PT J AU Bohnsack, JA Ecklund, AM Szmant, AM AF Bohnsack, JA Ecklund, AM Szmant, AM TI Artificial reef research: Is there more than the attraction-production issue? SO FISHERIES LA English DT Article ID FISH POPULATIONS RP NATL MARINE FISHERIES SERV, MIAMI LAB, SE FISHERIES SCI CTR, 75 VIRGINIA BEACH DR, MIAMI, FL 33149 USA. NR 12 TC 56 Z9 58 U1 2 U2 24 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 0363-2415 EI 1548-8446 J9 FISHERIES JI Fisheries PD APR PY 1997 VL 22 IS 4 BP 14 EP 16 PG 3 WC Fisheries SC Fisheries GA WQ998 UT WOS:A1997WQ99800004 ER PT J AU Broadhurst, MK Kennelly, SJ Watson, JW Workman, IK AF Broadhurst, MK Kennelly, SJ Watson, JW Workman, IK TI Evaluations of the Nordmore grid and secondary bycatch-reducing devices (BRD's) in the Hunter River prawn-trawl fishery, Australia SO FISHERY BULLETIN LA English DT Article ID BY-CATCH; REDUCTION AB Several bycatch-reducing devices (BRD's) were compared for their effectiveness in reducing bycatch while maintaining catches of prawns in an estuarine prawn-trawl fishery in New South Wales (NSW), Australia. A solid separator-panel (the Nordmore grid), a soft separator panel (the commercially used blubber chute), and four secondary BRD's (the fisheye, extended mesh funnel, Allerio Brothers grid, and square-mesh panel) each attached to a Nordmore grid, were compared against each other in a series of paired comparisons in the Hunter River prawn-trawl. fishery. The results showed that the Nordmore grid and all secondary BRD's caught less bycatch and more prawns than the commercially used blubber chute. Most bycatch seemed to escape with use of the Nordmore grid, and there was no significant advantage in adding a secondary BRD to this design. The efficiency of the Nordmore grid has led to its voluntary adoption by many commercial prawn-trawl fishermen throughout NSW estuaries. C1 MISSISSIPPI LABS,NATL MARINE FISHERIES SERV,PASCAGOULA FACIL,PASCAGOULA,MS 39568. RP Broadhurst, MK (reprint author), NEW S WALES AGR & FISHERIES,FISHERIES RES INST,POB 21,CRONULLA,NSW 2230,AUSTRALIA. RI Broadhurst, Matt/I-6783-2015 OI Broadhurst, Matt/0000-0003-0184-7249 NR 17 TC 9 Z9 10 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1997 VL 95 IS 2 BP 209 EP 218 PG 10 WC Fisheries SC Fisheries GA WU782 UT WOS:A1997WU78200003 ER PT J AU Johnson, LL Sol, SY Lomax, DP Nelson, GM Sloan, CA Casillas, E AF Johnson, LL Sol, SY Lomax, DP Nelson, GM Sloan, CA Casillas, E TI Fecundity and egg weight in English sole, Pleuronectes vetulus, from Puget Sound, Washington: Influence of nutritional status and chemical contaminants SO FISHERY BULLETIN LA English DT Article ID SUCKER CATOSTOMUS-COMMERSONI; CLUPEA-HARENGUS-PALLASI; PAROPHRYS-VETULUS; REPRODUCTIVE SUCCESS; WINTER FLOUNDER; NORTH-SEA; PSEUDOPLEURONECTES-AMERICANUS; POLYCHLORINATED-BIPHENYLS; OVARIAN DEVELOPMENT; AROMATIC-COMPOUNDS AB Differences in fecundity and egg weight were evaluated in English sole, Pleuronectes vetulus, from four sites in Puget Sound (the Duwamish Waterway Eagle Harbor, Sinclair Inlet, and Port Susan) with differing concentrations and types of sediment contamination. Duwamish Waterway sediment has high concentrations of both polychlorinated biphenyls (PCB's) and polycyclic aromatic hydrocarbons (PAH's), Eagle Harbor sediment has high concentrations of PAH's, and Sinclair Inlet sediment has low concentrations of PAH's and moderate concentrations of PCB's, whereas sediments at Port Susan, the reference site, are minimally contaminated. Fish from the Duwamish Waterway and Eagle Harbor had significantly higher levels of fluorescent aromatic compounds (FAC's) in bile than sole from Port Susan and Sinclair Inlet, and fish from the Duwamish Waterway had significantly higher concentrations of PCB's in ovary and liver tissue than fish from the other sampling sites. Fecundity and egg weight were compared in fish of equivalent size, age, and reproductive maturity from the four sites; fish from the Duwamish Waterway showed significantly higher relative fecundity and lower egg weight than fish collected from the three other sites. Production of more and smaller eggs in fish from the Duwamish Waterway site was associated with elevated hepatosomatic indices, elevated plasma triglyceride levels, and elevated levels of PCB's in liver and ovarian tissue, and reduced plasma vitellogenin levels (as estimated from alkali-labile protein (ALP) concentrations). Fish from the Duwamish Waterway and Sinclair Inlet also had higher age-specific fecundity than animals from other sites because of their larger size at age. On an individual fish basis, elevated tissue PCB concentrations were significantly correlated with low plasma ALP, reduced egg weight, and increased egg number, whereas elevated biliary FAC's were associated with increased ovarian atresia, increased egg weight, and reduced egg number. The results of this study suggest that English sole exposed to chemical contaminants may experience alterations in egg development; however, nutritional or other environmental factors may also contribute to the observed intersite differences in egg weight and fecundity. RP Johnson, LL (reprint author), NOAA, NATL MARINE FISHERIES SERV, NW FISHERIES SCI CTR, ENVIRONM CONSERVAT DIV, 2725 MONTLAKE BLVD E, SEATTLE, WA 98112 USA. NR 92 TC 24 Z9 26 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 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1997 VL 95 IS 2 BP 231 EP 249 PG 19 WC Fisheries SC Fisheries GA WU782 UT WOS:A1997WU78200005 ER PT J AU Lamkin, J AF Lamkin, J TI The Loop Current and the abundance of larval Cubiceps pauciradiatus (Pisces: Nomeidae) in the Gulf of Mexico: Evidence for physical and biological interaction SO FISHERY BULLETIN LA English DT Article ID OF-MEXICO; HYDROGRAPHIC FEATURES; CURRENT PATTERNS; CURRENT BOUNDARY; CYCLONIC EDDIES; WESTERN GULF; EASTERN GULF; BUCHAN AREA; FISH; VARIABILITY AB By analyzing annual ichthyoplankton survey data from 1983 to 1988, I found a significant positive correlation in distribution and abundance between larval Cubiceps pauciradiatus and the Loop Current in the Gulf of Mexico. The data indicate that C. pauciradiatus is a species whose adult spawning grounds and larval habitat are tied to sharp temperature gradients. These gradients occur along the edge of the Loop Current in the eastern Gulf of Mexico and along the anticyclonic-cyclonic rings in the western Gulf of Mexico. Transects made across the Loop Current, in 1987 and 1988, show that larval C. pauciradiatus is found close to the frontal interface and that peak abundance occurs before peak SST (sea surface temperature). Variation in the extent of the frontal systems in the Gulf of Mexico would be expected to affect annual recruitment of a species that is tied to a frontal habitat. Annual abundance of C. pauciradiatus varied considerably but was similar to that of other pelagic species. This finding suggests that the physical processes in the Gulf of Mexico may affect a wide range of species. RP Lamkin, J (reprint author), NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES CTR,75 VIRGINIA BEACH DR,MIAMI,FL 33149, USA. NR 60 TC 8 Z9 8 U1 1 U2 3 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1997 VL 95 IS 2 BP 250 EP 266 PG 17 WC Fisheries SC Fisheries GA WU782 UT WOS:A1997WU78200006 ER PT J AU Lenarz, WH Shaw, FR AF Lenarz, WH Shaw, FR TI Estimates of tag loss from double-tagged sablefish, Anoplopoma fimbria SO FISHERY BULLETIN LA English DT Article ID NORTHEASTERN PACIFIC; MORTALITY; RATES; EXPLOITATION; MOVEMENT AB Between 1986 and 1988, 10,545 double-tagged sablefish were released off California, Oregon, and Washington. Tags recovered from these fish have provided one of the best sets of data available for estimating tag-shedding rates. We developed a new model and a maximum-likelihood procedure to estimate the rates. Both initial and long-term shedding rates were low, but posteriorly placed tags were shed at about twice the rate of anteriorly placed tags. Bootstrapping indicated that the estimates were precise and accurate. Shedding rates for sablefish were considerably lower than most published estimates for other species. Although the rates were low, the extra tag increased recoveries by nine percent over a six-year period. C1 NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115. RP Lenarz, WH (reprint author), NOAA,NATL MARINE FISHERIES SERV,TIBURON LAB,3150 PARADISE DR,TIBURON,CA 94920, USA. NR 41 TC 4 Z9 4 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1997 VL 95 IS 2 BP 293 EP 299 PG 7 WC Fisheries SC Fisheries GA WU782 UT WOS:A1997WU78200009 ER PT J AU Lutcavage, M Kraus, S Hoggard, W AF Lutcavage, M Kraus, S Hoggard, W TI Aerial survey of giant bluefin tuna, Thunnus thynnus, in the great Bahama Bank, Straits of Florida, 1995 SO FISHERY BULLETIN LA English DT Article AB Aerial surveys were conducted daily from 19 May to 9 June 1995 to document the apparent abundance and migration behavior of giant bluefin tuna, Thunnus thynnus, over the Great Bahama Bank region of the Straits of Florida. Our objectives mere to conduct an aerial assessment of giant bluefin tuna in this region and to compare our results with previous aerial surveys conducted in the 1950's and 1970's. Two professional bluefin spotter pilots flew 70-nmi transect surveys along ''Tuna Alley'' as well as surveys into adjacent areas in search of bluefin tuna. The present study area was broader than that surveyed in the 1970's, which consisted of repeated flight tracks, each 1 nmi, across Tuna Alley at a point just south of South Cat Cay. Spotter aircraft carried a data acquisition system consisting of a global positioning system (GPS), a laptop computer, and a 35-mm camera to photograph schools. A total of 839 giant bluefin tuna were documented, within range of totals counted in the 1974-76 surveys (368-3,125 bluefin tuna). Single fish and loosely aggregated schools of up to 100 fish were seen travelling steadily north along the western flank of the Great Bahama Bank. They did not engage in feeding, smashing, or cartwheeling behaviors that are exhibited in New England waters. AU bluefin tuna appeared to be ''large giants,'' weighing an estimated 227 kg and over. There is little information documenting the origins and previous locations of giant bluefin tuna travelling along the Great Bahama Bank; therefore the use of direct counts of bluefin tuna in this region as an index of spawning biomass would require further documentation. C1 NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,PASCAGOULA,MS 39568. RP Lutcavage, M (reprint author), NEW ENGLAND AQUARIUM,EDGERTON RES LAB,CENT WHARF,BOSTON,MA 02110, USA. NR 6 TC 22 Z9 22 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 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1997 VL 95 IS 2 BP 300 EP 310 PG 11 WC Fisheries SC Fisheries GA WU782 UT WOS:A1997WU78200010 ER PT J AU McDermott, SF Lowe, SA AF McDermott, SF Lowe, SA TI The reproductive cycle and sexual maturity of Atka mackerel, Pleurogrammus monopterygius, in Alaska Waters SO FISHERY BULLETIN LA English DT Article AB The reproductive biology and sexual maturity of Atka mackerel (Pleurogrammus monopterygius) in Alaskan waters were examined with data collected from commercial fishing vessels and National Marine Fisheries Service research surveys. The female reproductive system and ovarian development over time were described by using histological methods. The reproductive cycle is characterized by a period of slow development from January until May, a rapid growth period of vitellogenesis in June, and a protracted spawning period, July until October, during which three batches of eggs are spawned an average. Length and age at maturity were calculated and compared for different subareas of the Aleutian Islands and Gulf of Alaska region. Size at 50% maturity was significantly different among the subareas,decreasing from east to west. Lengths at 50% maturity were 38.24, 35.91, 33.55, and 33.64 cm in the Gulf of Alaska, eastern Aleutian Islands, central Aleutian Islands, and western Aleutian Islands, respectively. Age at maturity was not significantly different by area; Atka mackerel were found to reach 50% maturity at 3.6 years. Therefore, it was assumed that different sizes at sexual maturity were reflections of different growth rates in the respective geographic subareas. C1 NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115. RP McDermott, SF (reprint author), UNIV WASHINGTON,SCH FISHERIES,SEATTLE,WA 98115, USA. NR 14 TC 21 Z9 22 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 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1997 VL 95 IS 2 BP 321 EP 333 PG 13 WC Fisheries SC Fisheries GA WU782 UT WOS:A1997WU78200012 ER PT J AU Robertson, KM Chivers, SJ AF Robertson, KM Chivers, SJ TI Prey occurrence in pantropical spotted dolphins, Stenella attenuata, from the eastern tropical Pacific SO FISHERY BULLETIN LA English DT Article ID PHOCOENA-PHOCOENA L; STOMACH CONTENTS; PORPOISE; LACTATION; GROWTH; DIET AB Identified prey of pan-tropical spotted dolphins, Stenella attenuata, include 56 species of fish and 36 species of cephalopods. Species identifications were made from fish otoliths and cephalopod beaks recovered from 428 stomachs collected throughout the eastern tropical Pacific between 1989 and 1991. The most frequently found fish were lanternfish (family Myctophidae) at 40%, and the most frequently found cephalopods were flying squids (family Ommastrephidae) at 65%. The dominance of these primarily mesopelagic prey species and a significantly higher stomach fullness index for stomachs collected during the morning hours (chi(2)=112.99, df=6, P<0.0001) suggest that pantropical spotted dolphins feed at night when many mesopelagic species migrate toward the surface. Significant differences in prey composition by season and geographic region indicate that pantropical spotted dolphins are flexible in their diet and may be opportunistic feeders. Comparison of the diets of pregnant and lactating female dolphins revealed that lactating females increase both the proportion of squid in their diet and quantity of food consumed. RP Robertson, KM (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,POB 271,LA JOLLA,CA 92038, USA. NR 82 TC 38 Z9 38 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1997 VL 95 IS 2 BP 334 EP 348 PG 15 WC Fisheries SC Fisheries GA WU782 UT WOS:A1997WU78200013 ER PT J AU Levy, H Kasibhatla, PS Moxim, WJ Klonecki, AA Hirsch, AI Oltmans, SJ Chameides, WL AF Levy, H Kasibhatla, PS Moxim, WJ Klonecki, AA Hirsch, AI Oltmans, SJ Chameides, WL TI The global impact of human activity on tropospheric ozone SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID UNITED-STATES; TRANSPORT; EXPORT AB Within a conceptual framework of stratospheric injection, CO-CH4 background tropospheric chemistry, parameterized pollution production in the continental boundary layer and surface deposition, we use an 11 level GCTM to simulate global distributions of present and pre-industrial tropospheric O-3. The chemistry is driven by previously simulated present and preindustrial NOx fields, while prescribed fields of CO, CH4 and H2O are held constant. An evaluation with measurements from 12 surface sites, 21 ozonesonde sites and 1 aircraft campaign finds agreement within +/-25% for 73% of the observations while identifying systematic; errors in the wintertime high-latitude Northern Hemisphere (NH), the Southern Hemisphere (SH) tropics during biomass burning, and the remote SH. We predict that human activity has increased the annual integral of tropospheric ozone by 39% with 3/4's of that increase in the free troposphere, though the boundary layer [BL] annual integral has increased by 66%. The 2 largest components of the global O-3 budget are stratospheric injection at 696 TgO(3)/yr, and loss through dry deposition, which increases from 459 TgO(3)/yr to a present level of 825 TgO(3)/yr. While tropospheric chemistry's net contribution is relatively small, changing from a preindustrial destruction of -236 TgO(3)/yr to a present production of +128 TgO(3)/yr, it is a balance between two much larger terms, -558 TgO(3)/yr of destruction in the background troposphere and +686 TgO(3)/yr of production in the polluted boundary layer. Human impact on O-3 predominates in the summertime extratropical NH and in the tropics during their biomass burning seasons [increases of 50%-100% or more]. Conversely, there has been little increase in most of the upper troposphere [<20%], where ozone's influence on tropospheric climate is strongest. C1 MCNC,ENVIRONM PROGRAMS,RES TRIANGLE PK,NC 27709. UNIV CALIF IRVINE,DEPT EARTH SYST SCI,IRVINE,CA 92697. NOAA,CLIMATE MONITORING & DIAGNOST LAB,BOULDER,CO 80303. GEORGIA INST TECHNOL,EAS,ATLANTA,GA 30332. PRINCETON UNIV,ATMOSPHER & OCEAN SCI PROGRAM,PRINCETON,NJ 08542. RP Levy, H (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,POB 308,PRINCETON,NJ 08542, USA. RI Kasibhatla, Prasad/A-2574-2010; OI Kasibhatla, Prasad/0000-0003-3562-3737 NR 20 TC 75 Z9 76 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 1 PY 1997 VL 24 IS 7 BP 791 EP 794 DI 10.1029/97GL00599 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WR211 UT WOS:A1997WR21100015 ER PT J AU Vomel, H Rummukainen, M Kivi, R Karhu, J Turunen, T Kyro, E Rosen, J Kjome, N Oltmans, S AF Vomel, H Rummukainen, M Kivi, R Karhu, J Turunen, T Kyro, E Rosen, J Kjome, N Oltmans, S TI Dehydration and sedimentation of ice particles in the Arctic stratospheric vortex SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WATER-VAPOR; WINTER; EVOLUTION; OZONE AB Balloon borne frost-point hygrometers and backscatter sondes were launched at Sodankyla, Finland in January and February of 1996. These instruments measure water vapor and the backscatter ratio of light due to polar stratospheric clouds in the Arctic stratospheric vortex. Here we report the results of a hygrometer sonde and a backscatter sonde launched within 3.5 hours of each other on January 22/23. Together these soundings show a strong loss of water vapor due to the formation of ice clouds as a result of record cold temperatures in the Arctic stratosphere. The separation of the upper edge of the layer showing water vapor loss and the upper edge of the PSC layer indicates sedimentation of the ice particle layer, possibly leading to a permanent dehydration in the upper part of the layer exhibiting water vapor loss. C1 UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. UNIV WYOMING,DEPT PHYS & ASTRON,LARAMIE,WY 82071. SODANKYLA OBSERV,FINNISH METEOROL INST,FIN-99600 SODANKYLA,FINLAND. NOAA,CLIMATE MONITORING & DIAGNOST LAB,BOULDER,CO 80303. NR 18 TC 41 Z9 41 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 1 PY 1997 VL 24 IS 7 BP 795 EP 798 DI 10.1029/97GL00668 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WR211 UT WOS:A1997WR21100016 ER PT J AU Nevison, CD Solomon, S Garcia, RR AF Nevison, CD Solomon, S Garcia, RR TI Model overestimates of NOy in the upper stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOWER THERMOSPHERE; MESOSPHERE; DYNAMICS; NITROGEN AB Stratospheric NOy profiles from the Garcia-Solomon two-dimensional model are compared to observed profiles from the Upper Atmosphere Research Satellite (UARS) and the Atmospheric Trace Molecule Spectroscopy Experiment (ATMOS). The model consistently overestimates NOy in the upper stratosphere beyond the range of uncertainty in the satellite data. The relatively short lifetime of NOy in this region suggests a largely photochemical explanation for the discrepancy. Uncertainties in the photochemical production of NOy from N2O strongly influence stratospheric NOy profiles, but this influence decreases with increasing height in the upper stratosphere. Photochemical loss of NO is controlled by the NO photolysis rate and the reaction rates of N + NO and N + O-2. All these rates are subject to substantial uncertainties that probably contribute to the discrepancy between model and observations. C1 NATL CTR ATMOSPHER RES,BOULDER,CO 80307. NOAA,ENVIRONM RES LAB,BOULDER,CO 80303. NR 17 TC 17 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 1 PY 1997 VL 24 IS 7 BP 803 EP 806 DI 10.1029/97GL00549 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WR211 UT WOS:A1997WR21100018 ER PT J AU Baker, DJ AF Baker, DJ TI Presidential initiatives & the geosciences SO GEOTIMES LA English DT Editorial Material RP Baker, DJ (reprint author), NOAA,WASHINGTON,DC 20230, USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU AMER GEOLOGICAL INST PI ALEXANDRIA PA 4220 KING ST, ALEXANDRIA, VA 22302-1507 SN 0016-8556 J9 GEOTIMES JI Geotimes PD APR PY 1997 VL 42 IS 4 BP 5 EP 5 PG 1 WC Geosciences, Multidisciplinary SC Geology GA WR555 UT WOS:A1997WR55500007 ER PT J AU Fogarty, MJ Addison, JT AF Fogarty, MJ Addison, JT TI Modelling capture processes in individual traps: Entry, escapement and soak time SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article DE binomial distribution; Poisson distribution; stochastic models ID FISH TRAPS; CRAB; DENSITY; LOBSTER AB Stationary fishing gear is employed in a diverse array of fisheries including those for many high unit-value species. The mode of operation of these gear types (traps, long-lines, gillnets, etc.) requires special consideration in the development of abundance indices because of gear saturation effects. Specifically, factors affecting the probability of capture and of escapement or other sources of loss must be addressed. Here, we describe two models of capture processes in traps that include existing models as special cases. Deterministic models are first developed to illustrate the basic principles. Stochastic analogues of two well-known models are then described using the theory of birth-death stochastic processes. II is shown that the mean of the stochastic models is identical to the deterministic case for models where closed form solutions are possible. The stochastic models provide additional diagnostic information in terms of the variance and the probability distribution of catch levels. Illustrations of this approach are provided for experimental observations on ingress and catch for the American lobster (Homarus americanus). (C) 1997 international Council for the Exploration of the Sea. C1 NOAA,NATL MARINE FISHERIES SERV,WOODS HOLE,MA 02543. CTR ENVIRONM FISHERIES & AQUACULTURE SCI,LOWESTOFT NR33 OHT,SUFFOLK,ENGLAND. NR 47 TC 27 Z9 28 U1 1 U2 9 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD APR PY 1997 VL 54 IS 2 BP 193 EP 205 DI 10.1006/jmsc.1996.9998 PG 13 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA WZ751 UT WOS:A1997WZ75100005 ER PT J AU Knopp, KJ Christensen, DH Hill, JR AF Knopp, KJ Christensen, DH Hill, JR TI Vertical-cavity surface-emitting lasers with low-ripple optical pumping windows SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article; Proceedings Paper CT 15th IEEE International Semiconductor Laser Conference (HAIFA 1996 ISLC) CY OCT 13-18, 1996 CL HAIFA, ISRAEL SP IEEE, Lasers & Electro Opt Soc, S Neaman Inst, ECI Telecom, Semiconductor Devices, Technion, Israel Inst Technol, Israeli Minist Sci & Arts DE distributed Bragg reflector lasers; laser resonators; optical pumping; thin-film devices; semiconductor lasers ID DISTRIBUTED BRAGG REFLECTORS; MOLECULAR-BEAM EPITAXY; GROWTH AB A general technique for numerically optimizing the optical admittances in vertical-cavity structures is used to suppress the interference ripple in the typical reflectance/transmittance spectra. This technique is applicable to any vertical-cavity device whose photonic properties at various wavelengths requires modification for specific applications. In this paper, we report the use of this optimization method to enhance the coupling of pump light into 850-nm vertical-cavity surface-emitting lasers (VCSEL's). We have designed and fabricated novel lasers which contain a wideband window of low reflectance amidst the typical interference fringe spectrum. The 750-800-nm region for the low-ripple design has an average reflectance of 5%; the peak-to-peak amplitude of the ripple is 0.25%. The sensitivity of these devices to temperature variations and layer-thickness manufacturing variations is also studied. The low-ripple pump window shifts at a rate of 0.036 nm/degrees C, the peak-to-peak ripple of the reflectance varies less than 2%, and the pump bandwidth remains constant, over temperatures ranging from 0 degrees C to 100 degrees C. The low-ripple structure substantially reduces the temperature and wavelength variation of the pump-field overlap by creating a window of nearly constant reflectance. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. UNIV COLORADO,DEPT ELECT & COMP ENGN,BOULDER,CO 80309. RP Knopp, KJ (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 20 TC 8 Z9 8 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD APR PY 1997 VL 3 IS 2 BP 366 EP 371 DI 10.1109/2944.605680 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA XP732 UT WOS:A1997XP73200034 ER PT J AU Walker, DK Williams, DF AF Walker, DK Williams, DF TI Compensation for geometrical variations in coplanar waveguide probe-tip calibration SO IEEE MICROWAVE AND GUIDED WAVE LETTERS LA English DT Article DE automatic network analyzers; coplanar waveguide; on-wafer calibration AB We show how coplanar-waveguide probe-tip scattering parameter calibrations performed in one coplanar waveguide conductor geometry may be adjusted for measurement in another. The method models the difference between the two probe-tip-to-coplanar-waveguide transitions as a change in shunt capacitance and applies previously developed techniques for its determination and compensation. Comparison to accurate multiline Thru-Reflect-Line calibrations verifies the accuracy of the method. Differences in both conductor geometry and substrate permittivity are considered in the comparison. The method requires only a single, compact open stub or thru line fabricated on the measurement wafer. RP Walker, DK (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 6 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 SN 1051-8207 J9 IEEE MICROW GUIDED W JI IEEE Microw. Guided Wave Lett. PD APR PY 1997 VL 7 IS 4 BP 97 EP 99 DI 10.1109/75.563631 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA WR246 UT WOS:A1997WR24600001 ER PT J AU Shirley, JH AF Shirley, JH TI Velocity distributions calculated from the Fourier transforms of Ramsey lineshapes SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY DE Fourier transform; frequency standard; NIST-7; Ramsey lineshape; second-order Doppler shift; transit time; velocity distribution AB A computerized method for finding velocity distributions from the Fourier transforms of Ramsey Iineshapes has been developed, Experimental and numerical tests of the method show that it works very wed for broad distributions and lineshapes where the drift time is much longer than the excitation time, The method is routinely used to find velocity distributions for the primary frequency standard NIST-7, The second-order Doppler shift is calculated from these distributions,vith an uncertainty of a few tenths of 1 percent. RP Shirley, JH (reprint author), NATL INST STAND & TECHNOL, DIV TIME & FREQUENCY, BOULDER, CO 80303 USA. NR 9 TC 20 Z9 20 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 117 EP 121 DI 10.1109/19.571788 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900008 ER PT J AU Ye, J Ma, LS Hall, JL AF Ye, J Ma, LS Hall, JL TI Ultrastable optical frequency reference at 1.064 mu m using a C2HD molecular overtone transition SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY ID 532 NM; SPECTROSCOPY AB Saturated molecular overtone transitions in the visible and near infrared can be detected with record-high sensitivities using our cavity-enhanced frequency modulation technique, We have stabilized a Nd:YAG laser onto the P(5) line in (v(2) +/- 3v(3)) overtone band of C2HD at 1.064 mu m and established its absolute frequency, Excellent signal-to-noise ratio produced an Allan variance of 3.4 x 10(-13) at 1 s averaging, improving to 1 x 10(-14) after 800 s, Selection of slow molecules with low power and gas pressure gave a linewidth 13 times below the room temperature transit time limit. C1 NIST,BOULDER,CO 80309. E CHINA NORMAL UNIV,DEPT PHYS,SHANGHAI,PEOPLES R CHINA. NATL INST STAND & TECHNOL,DIV QUANTUM PHYS,BOULDER,CO 80309. RP Ye, J (reprint author), UNIV COLORADO,BOULDER,CO 80309, USA. RI Ye, Jun/C-3312-2011 NR 16 TC 36 Z9 37 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 178 EP 182 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900023 ER PT J AU Ascarrunz, FG Jefferts, SR Parker, TE AF Ascarrunz, FG Jefferts, SR Parker, TE TI Earth station errors in two-way time and frequency transfer SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB We have investigated the earth station errors in two-way time transfer, A 3.7-m earth station and a very small aperture terminal earth station were used in these experiments along with a transponder located on a mountain about 10 km away, The temperature coefficient of the receive delay for the 3.7 m NIST earth station was (-150 +/- 30) ps/K, and the temperature coefficient for the transmit delay was (-50 +/- 10) ps/K, The overall temperature coefficient for the earth station was (100 +/- 30) ps/K, Aside from environmental errors there are apparent changes in delay due to characteristics of the modulation/demodulation scheme. Apparent delay changes due to nonlinearity effects in the earth station were as high as 10 ns, The errors due to code dependence and third code interference were sometimes as high as 3 ns. RP Ascarrunz, FG (reprint author), NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,BOULDER,CO 80303, USA. NR 3 TC 5 Z9 10 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 205 EP 208 DI 10.1109/19.571813 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900029 ER PT J AU Jefferts, SR Weiss, MA Levine, J Dilla, S Bell, EW Parker, TE AF Jefferts, SR Weiss, MA Levine, J Dilla, S Bell, EW Parker, TE TI Two-way time and frequency transfer using optical fibers SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB The National Institute of Standards and Technology (NIST) has built a two-way time-transfer device which uses any currently unused byte in the SONET (SDH) overhead to effect time transfer, The hardware shows stability which allows time transfer over short distances (km) with stabilities less than 10 ps. Time transfer over distances that require additional amplifiers in the fiber have not yet been investigated, Accuracy at the same level should also be possible. RP Jefferts, SR (reprint author), NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,BOULDER,CO 80303, USA. NR 2 TC 11 Z9 14 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 209 EP 211 DI 10.1109/19.571814 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900030 ER PT J AU Hamilton, CA Burroughs, CJ Benz, SP Kinard, JR AF Hamilton, CA Burroughs, CJ Benz, SP Kinard, JR TI AC Josephson voltage standard: Progress report SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY DE AC; digital-to-analog converter; Josephson; standard; voltage; waveform synthesis AB Progress toward a Josephson voltage standard for fast de measurements and accurate ac waveform synthesis is described, A superconductor-normal-superconductor (SNS) junction process is used to make 5 mA critical current arrays with up to 32 768 junctions, With rf excitation at 11 GHz these arrays generate milliampere constant-voltage steps, A bias control circuit that provides output current amplification, transient suppression, and submicrosecond settling time is used with both superconductor-insulator-superconductor (SIS) and SNS junction arrays for fast, automated measurements of A/D converter linearity, a test for subnanovolt accuracy, waveform synthesis, and a preliminary measurement of the ac-dc difference of a thermal voltage converter. RP Hamilton, CA (reprint author), NATL BUR STAND & TECHNOL,BOULDER,CO 80303, USA. NR 6 TC 34 Z9 35 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 224 EP 228 DI 10.1109/19.571818 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900034 ER PT J AU Hamilton, CA Burroughs, CJ Kupferman, SL Naujoks, GA Vickery, A AF Hamilton, CA Burroughs, CJ Kupferman, SL Naujoks, GA Vickery, A TI A compact transportable Josephson voltage standard SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY DE DC; Josephson; standard; transportable; voltage AB The development of a compact, portable 10 V Josephson calibration system is described, Its accuracy is the same as typical laboratory systems, but its weight and volume are reduced by more than a factor of three, The new system will replace conventional travelling voltage standards used within several NASA and DOE standards laboratories. C1 KEITHLEY INSTRUMENTS INC,SOLON,OH 44139. MILLITECH CORP,S DEERFIELD,MA 01373. RP Hamilton, CA (reprint author), NATL INST STAND & TECHNOL,BOULDER,CO 80303, USA. NR 3 TC 17 Z9 17 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 237 EP 241 DI 10.1109/19.571821 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900037 ER PT J AU Jeffery, AM Elmquist, RE Lee, LH Shields, JQ Dziuba, RF AF Jeffery, AM Elmquist, RE Lee, LH Shields, JQ Dziuba, RF TI NIST comparison of the quantized hall resistance and the realization of the SI OHM through the calculable capacitor SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY ID NBS AB The latest NIST result from the comparison of the quantized Hall resistance (QHR) with the realization of the SI ohm obtained from the NIST calculable capacitor is reported, A small difference between the 1988 result and the present result has led to a re-evaluation of the sources and magnitudes of possible systematic errors. RP Jeffery, AM (reprint author), NIST,DIV ELECT,ELECT & ELECT ENGN LAB,TECHOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 10 TC 58 Z9 59 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 264 EP 268 DI 10.1109/19.571828 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900044 ER PT J AU Zimmerman, NM Cobb, JL Clark, AF AF Zimmerman, NM Cobb, JL Clark, AF TI Recent results and future challenges for the NIST charged-capacitor experiment SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY ID ELECTRON AB This paper reports on recent results in some of the work toward developing a new capacitance standard using single electron tunneling (SET) devices, In particular, we plan on using a SET pump to charge a cryogenic standard capacitor and measure the voltage that develops, In this paper, we summarize: 1) measurements of the ratio of two capacitors in a bridge configuration, using a SET transistor as the null detector and 2) stability and leakage measurements on the cryogenic capacitors, We then discuss in detail several of the possible challenges, including the effects of stray capacitance and line impedance, and resulting requirements on the sensitivity of the SET null detector. RP Zimmerman, NM (reprint author), NIST,DIV ELECT,ELECT & ELECT ENGN LAB,TECHNOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 6 TC 7 Z9 7 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 294 EP 298 DI 10.1109/19.571835 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900051 ER PT J AU Keller, MW Martinis, JM Steinbach, AH Zimmerman, NM AF Keller, MW Martinis, JM Steinbach, AH Zimmerman, NM TI A seven-junction electron pump: Design, fabrication, and operation SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB We have developed a seven-junction electron pump for use in a new standard of capacitance based on measuring the voltage produced when a known charge is placed on a capacitor, This new pump,,with an error per pumped electron of 15x10(-9), is about 30 times more accurate than a five-junction pump made previously at NIST, By careful design of the pump geometry, we have reduced the effect of cross capacitance and simplified device operation. Our fabrication recipe produces small, stable tunnel junctions relatively quickly and reliably, We have developed a method of tuning the pump for highly accurate electron counting, This tuning can be quickly repeated whenever fluctuations in background charges degrade accuracy. C1 NIST,GAITHERSBURG,MD 20899. RP Keller, MW (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 11 TC 27 Z9 28 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 307 EP 310 DI 10.1109/19.571841 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900054 ER PT J AU Elmquist, RE Dziuba, RF AF Elmquist, RE Dziuba, RF TI Loading effects in resistance scaling SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB Reference resistors are affected by the heating of the resistor element caused by the measurement current. The effects of such loading are complex and can change in magnitude as a function of the initial state of the resistor and the external environment. This paper describes a method for determining relative load coefficients by using cryogenic current comparator ratio measurements in a two-step scaling process. Previously undiscovered loading effects are analyzed using a resistance element made from copper, which has an easily measured change of resistance with temperature. The magnitude of loading effects in several types of resistors are listed. RP Elmquist, RE (reprint author), NIST,DIV ELECT,ELECT & ELECT ENGN LAB,TECHNOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 4 TC 8 Z9 8 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 322 EP 324 DI 10.1109/19.571847 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900058 ER PT J AU Jarrett, DG AF Jarrett, DG TI Automated guarded bridge for calibration of multimegohm standard resistors from 10 M Omega to 1 T Omega SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB The implementation of an automated guarded bridge for calibrating multimegohm standard resistors is described. A guarded multimegohm bridge has been assembled with programmable dc calibrators in two of the arms allowing multiple ratios and test voltages to be remotely selected. A programmable electrometer with a resolution of +/-3 fA in the current mode is used to measure the difference in currents flowing through the remaining two arms of the bridge consisting of unknown and standard resistors. The balancing algorithm used to estimate the calibrator setting required to obtain a null is described along with a graphical user interface (GUI) that has been written to provide flexibility to the measurement system and improve control of the instrumentation. Evaluation of the multimegohm bridge from 10 M Omega to 1 T Omega is reported along with a comparison of the multimegohm bridge performance to that of the existing manual and semi-automated systems that the multimegohm bridge will replace. RP Jarrett, DG (reprint author), NIST,DIV ELECT,ELECT & ELECT ENGN LAB,TECHNOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 4 TC 34 Z9 34 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 325 EP 328 DI 10.1109/19.571848 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900059 ER PT J AU Huang, DX Rebuldela, G Harper, JD AF Huang, DX Rebuldela, G Harper, JD TI RF-DC differences of micropotentiometers SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY DE annular resistor; micropotentiometer; thermoelement; transmission line ID VOLTAGE STANDARDS AB Various sources for the rf-dc differences of micropotentiometers (micropots) are analyzed and calculated, The results are shown to agree well with experimental values, A new design is introduced that reduces the rf-de differences of the micropots significantly. Observations show good stability over a long period. This makes the micropot suitable as a primary rf and audio standard in the microvolt and millivolt ranges. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. RP Huang, DX (reprint author), BALLANTINE LABS INC,CEDAR KNOLLS,NJ 07927, USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 337 EP 341 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900062 ER PT J AU Kinard, JR Novotny, DB Lipe, TE Huang, DX AF Kinard, JR Novotny, DB Lipe, TE Huang, DX TI Development of thin-film multijunction thermal converters at NIST SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB This paper gives an overview of the development of thin-film multijunction thermal converters (FMJTC's) at the National Institute of Standards and Technology (NIST). A historical perspective of film thermal converters is presented, followed by descriptions of the motivation, fabrication processes, physical characteristics, and the electrical properties of the FMJTC's produced at NIST, Integrated micropotentiometers that incorporate FMJTC's and thermal converters, produced by an alternative fabrication technology using a CMOS foundry, are also described. The paper concludes with a report on the present status of the FMJTC project and future directions. C1 NIST,DIV SEMICOND ELECT,ELECT & ELECT ENGN LAB,TECHNOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899. BALLANTINE LABS INC,CEDAR KNOLLS,NJ 07927. RP Kinard, JR (reprint author), NIST,DIV ELECT,ELECT & ELECT ENGN LAB,TECHNOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 9 TC 16 Z9 17 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 347 EP 351 DI 10.1109/19.571853 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900064 ER PT J AU Oldham, NM AvramovZamurovic, S Parker, ME AF Oldham, NM AvramovZamurovic, S Parker, ME TI Exploring the low-frequency performance of thermal converters using circuit models and a digitally synthesized source SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY ID AC AB Low frequency errors of thermal voltage converters are described and estimated using a circuit model that includes easily measured parameters. A digitally synthesized source is used to confirm the estimated ac-dc differences in the 0.01 Hz to 40 Hz range. C1 USN ACAD,WEAPONS & SYST DEPT,ANNAPOLIS,MD 21402. RP Oldham, NM (reprint author), NIST,DIV ELECT,GAITHERSBURG,MD 20899, USA. NR 5 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 352 EP 355 DI 10.1109/19.571854 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900065 ER PT J AU Kinard, JR Lipe, TE Childers, CB Novotny, DB Huang, DX AF Kinard, JR Lipe, TE Childers, CB Novotny, DB Huang, DX TI High-current thin-film multijunction thermal converters and multiconverter modules SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB High-current, thin-film multijunction thermal converters (FMJTC's) have been fabricated at NIST with heater ranges from a few milliamperes to 1 A. Multiconverter modules containing high-current FMJTC's have also been constructed to measure currents up to 6 A at frequencies up to 100 kHz. C1 NIST,DIV SEMICOND ELECT,ELECT & ELECT ENGN LAB,TECHNOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899. BALLANTINE LABS INC,CEDAR KNOLLS,NJ 07927. RP Kinard, JR (reprint author), NIST,DIV ELECT,ELECT & ELECT ENGN LAB,TECHNOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 5 TC 3 Z9 3 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 391 EP 394 DI 10.1109/19.571863 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900074 ER PT J AU Oldham, NM AvramovZamurovic, S Parker, ME Waltrip, BC AF Oldham, NM AvramovZamurovic, S Parker, ME Waltrip, BC TI Low-voltage standards in the 10 Hz to 1 MHz range SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY DE calibration; impedance measurement; micropotentiometer; thermal converters; voltage measurement AB A step-down procedure is described for establishing voltage standards in the 2 mV to 200 mV range at frequencies between 10 Hz and 1 MHz. The step-down employs low-voltage thermal voltage converters and micropotentiometers. Techniques are given for measuring input impedance and calculating loading errors. C1 USN ACAD,WEAPONS & SYST DEPT,ANNAPOLIS,MD 21402. RP Oldham, NM (reprint author), NIST,DIV ELECT,ELECT & ELECT ENGN LAB,TECHNOL ADM,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 6 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 395 EP 398 DI 10.1109/19.571864 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900075 ER PT J AU Petersons, O FitzPatrick, GJ Simmon, ED AF Petersons, O FitzPatrick, GJ Simmon, ED TI An active high-voltage divider with 20 mu V/V uncertainty SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY DE compressed gas capacitor; electronic compensation; high-voltage divider ID BRIDGE AB A voltage divider has been developed consisting of an external compressed-gas capacitor, a group of stable solid-dielectric capacitors, and special electronic circuitry, A developmental prototype divider has been constructed and test results obtained to verify the operating principle and accuracy target. The new critical items enabling the desired performance are the solid-dielectric capacitors in the low-voltage arm, approaching the short-term stability of gas-insulated capacitors, and the active circuit consisting of a feedback amplifier, complemented with a controlled source, which essentially removes the error contribution from the feedback amplifier. RP Petersons, O (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 430 EP 434 DI 10.1109/19.571876 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900084 ER PT J AU Wait, DF Randa, J AF Wait, DF Randa, J TI Amplifier noise measurements at NIST SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB We have recently measured the noise characteristics of two low-noise commercial amplifiers in the 2.0-4.0 GHz frequency range, The tests were part of a program to develop and validate measurement methods for a noise-figure measurement service. Measured noise figures were about 0.5 +/- 0.04 dB, We present the results and the accompanying uncertainties. We also describe the measurement method and summarize the many checks that were used to validate the method. RP Wait, DF (reprint author), NATL INST STAND & TECHNOL,DIV ELECTROMAGNET FIELDS,BOULDER,CO 80303, USA. NR 12 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 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 482 EP 485 DI 10.1109/19.571891 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900097 ER PT J AU Ginley, RA AF Ginley, RA TI Line-reflect-match calibration technique for the dual six-port automatic network analyzer SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY ID ONLINE ACCURACY ASSESSMENT; 6-PORT ANA AB A newly developed method allows dual six-post automatic network analyzers (ANA's) to be calibrated with a single, known one-port termination instead of air line standards. This technique is especially useful for calibrations below 30 MHz, where air lines cannot be adequately characterized, The choice of the value of the standard is also discussed. RP NATL INST STAND & TECHNOL, 325 BROADWAY, BOULDER, CO 80303 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9456 EI 1557-9662 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 523 EP 526 DI 10.1109/19.571901 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900107 ER PT J AU Kessler, EG Schweppe, JE Deslattes, RD AF Kessler, EG Schweppe, JE Deslattes, RD TI Intercomparison of silicon samples from the avogadro projects SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY ID LATTICE-PARAMETERS; COMPARATOR AB The NIST lattice comparator assesses lattice parameter differences among carefully prepared samples of monocrystalline silicon with a level of imprecision near 10(-8). This instrument has recently been used to effect intercomparisons among samples from laboratories currently engaged in direct optical measurements of such lattice periods. We report lattice parameter differences among samples representative of current optical measurements in all active national measurement laboratories. These data are suggestive of the current state of the art of these determinations and the population of silicon materials presently available for such purposes. RP Kessler, EG (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 11 TC 14 Z9 14 U1 0 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 551 EP 555 DI 10.1109/19.571909 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900114 ER PT J AU Steiner, RL Gillespie, AD Fujii, K Williams, ER Newell, DB Picard, A Stenbakken, GN Olsen, PT AF Steiner, RL Gillespie, AD Fujii, K Williams, ER Newell, DB Picard, A Stenbakken, GN Olsen, PT TI The NIST watt balance: Progress toward monitoring the kilogram SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY DE absolute ampere; balance; fundamental constants; kilogram; mass standard; watt experiment AB The National Institute of Standards and Technology (NIST) watt balance is an experiment to compare measurements of the watt using electrical references (volt, ohm) to those using mechanical references (length, time, mass). A coil within a radial magnetic field has a dual use of: 1) generating a voltage by moving at some velocity to calibrate the magnetic flux density, and, 2) generating a force with electrical current to balance the gravitational force of a mass. This experiment has had several improvements made to it in the last year. These include the incorporation of three-laser interferometry and a refractometer to improve the velocity measurements, temperature control and coil rotation damping to reduce drifts and stabilize laser and mechanical alignments, and a gravimeter to determine local gravity. Systematic errors and scatter in long-term measurements have been greatly reduced in the last year, but statistically significant deviations relative to within-run uncertainty still persist. The source of these deviations has not yet been identified. Recent within-run standard deviations are generally near 0.1 mu W/W, which is the target precision of this present design. RP Steiner, RL (reprint author), TECHNOL ADM, DIV ELECT, ELECT & ELECT ENGN LAB, NATL INST STAND & TECHNOL, US DEPT COMMERCE, GAITHERSBURG, MD 20899 USA. NR 5 TC 20 Z9 20 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 601 EP 604 DI 10.1109/19.571932 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900126 ER PT J AU Gillespie, AD Fujii, K Newell, DB Olsen, PT Picard, A Steiner, RL Stenbakken, GN Williams, ER AF Gillespie, AD Fujii, K Newell, DB Olsen, PT Picard, A Steiner, RL Stenbakken, GN Williams, ER TI Alignment uncertainties of the NIST watt experiment SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT Conference on Precision Electromagnetic Measurements (CPEM 96) CY JUN 17-20, 1996 CL BRAUNSCHWEIG, GERMANY AB The effects of alignment uncertainties of the NIST watt balance with respect to local gravity and the magnetic flux density of the balance have been analyzed. Techniques for measuring all quantities relevant to misalignment have been developed. The components of the relative combined standard uncertainty of the measured value of the watt due to alignment uncertainties have been reduced to 20 nW/W, and potential improvements in the balance design have been identified which could ultimately lead to a reduction of that uncertainty to below 10 nW/W. RP Gillespie, AD (reprint author), TECHNOL ADM,DIV ELECT,ELECT & ELECT ENGN LAB,NATL INST STAND & TECHNOL,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 5 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 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1997 VL 46 IS 2 BP 605 EP 608 DI 10.1109/19.571933 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WY149 UT WOS:A1997WY14900127 ER PT J AU Elvidge, CD Baugh, KE Kihn, EA Kroehl, HW Davis, ER Davis, CW AF Elvidge, CD Baugh, KE Kihn, EA Kroehl, HW Davis, ER Davis, CW TI Relation between satellite observed visible-near infrared emissions, population, economic activity and electric power consumption SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article AB The area lit by anthropogenic visible-near infrared emissions (i.e., lights) has been estimated for 21 countries using night-time data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). The area lit is highly correlated to gross domestic product and electric power consumption. Significant outliers exist in the relation between area lit and population. The results indicate that the local level of economic development must be factored into the apportionment of population across the land surface based on DMSP-OLS observed lights. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. NOAA,NATL GEOPHYS DATA CTR,SOLAR TERR PHYS DIV,BOULDER,CO 80303. NOAA,NATL GEOPHYS DATA CTR,USAF,DEPT DEF LIAISON,BOULDER,CO 80303. RP Elvidge, CD (reprint author), UNIV NEVADA,DESERT RES INST,RENO,NV 89506, USA. RI Elvidge, Christopher/C-3012-2009 NR 12 TC 205 Z9 247 U1 5 U2 61 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD APR PY 1997 VL 18 IS 6 BP 1373 EP 1379 DI 10.1080/014311697218485 PG 7 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA WR306 UT WOS:A1997WR30600014 ER PT J AU Woicik, JC Pellegrino, JG Miyano, KE AF Woicik, JC Pellegrino, JG Miyano, KE TI Bond lengths and elasticity in strained-layer semiconductors SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 9th International Conference on X-Ray Absorption Fine Structure CY AUG 26-30, 1996 CL GRENOBLE, FRANCE SP European Synchrotron Radiat Facil, Ville Grenoble, Univ Joseph Fourier Grenoble, Minist Educ Natl, CNRS, CEA, Soc Francaise Chim, Jobin Yvon, Microcontrole, Eurisys Mesures, Inst Francais Petr, Air Liquide, Huber Diffrakt Teck, Haldor Topsoe A/S ID ABSORPTION FINE-STRUCTURE; EPITAXIAL LAYERS; HETEROSTRUCTURES AB The x-ray standing wave (XSW) and extended x-ray absorption fine structure (EXAFS) techniques have determined the strain and bond distortions in an InAs monolayer embedded in GaAs(001). A unifying picture of bond lengths and elasticity in strained-layer semiconductors is presented. C1 CUNY BROOKLYN COLL,DEPT PHYS,BROOKLYN,NY 11210. RP Woicik, JC (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 11 TC 1 Z9 1 U1 0 U2 3 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD APR PY 1997 VL 7 IS C2 BP 687 EP 689 DI 10.1051/jp4:1997205 PN 2 PG 3 WC Physics, Multidisciplinary SC Physics GA XQ952 UT WOS:A1997XQ95200006 ER PT J AU Cross, JO Newville, M Sorensen, LB Stragier, HJ Bouldin, CE Woicik, JC AF Cross, JO Newville, M Sorensen, LB Stragier, HJ Bouldin, CE Woicik, JC TI Separated anomalous scattering amplitudes for the inequivalent Cu sites in YBa2Cu3O7-delta using DAFS SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 9th International Conference on X-Ray Absorption Fine Structure CY AUG 26-30, 1996 CL GRENOBLE, FRANCE SP European Synchrotron Radiat Facil, Ville Grenoble, Univ Joseph Fourier Grenoble, Minist Educ Natl, CNRS, CEA, Soc Francaise Chim, Jobin Yvon, Microcontrole, Eurisys Mesures, Inst Francais Petr, Air Liquide, Huber Diffrakt Teck, Haldor Topsoe A/S ID DIFFRACTION AB The separate complex resonant scattering amplitudes for the two inequivalent Cu sites in YBa2Cu3O7-delta have been determined using diffraction anomalous fine structure (DAFS). The combined amplitudes Delta f(Q,E) for eight specular (00l) reflections were isolated from the measured intensity using the iterative dispersion algorithm of Pickering, et al., modified to accommodate contributions to the imaginary part of the scattering amplitude from the heavy Ba and Y atoms. The individual site response functions f ''(E) were solved by singular value decomposition of the matrix of crystallographic coefficients and applying the inverse matrix to Delta f(Q,E) at each value of energy. For comparison, a second set of coefficients was obtained by simultaneously fitting the DAFS fine structure functions chi(Q, k) using the computer program FEFFIT under a set of constraints. The chi(Q, k) were modeled as linear combinations of the two Cu site chi(k) functions using a kinematic structure factor model with Q as the independent variable and theoretical chi(k) from FEFF7. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV WASHINGTON,DEPT PHYS,SEATTLE,WA 98195. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Cross, JO (reprint author), USN,RES LAB,WASHINGTON,DC 20375, USA. NR 7 TC 9 Z9 9 U1 0 U2 3 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD APR PY 1997 VL 7 IS C2 BP 745 EP 747 DI 10.1051/jp4:1997224 PN 2 PG 3 WC Physics, Multidisciplinary SC Physics GA XQ952 UT WOS:A1997XQ95200025 ER PT J AU Newville, M Cross, JO Ravel, B Sorensen, LB Bouldin, CE Yacoby, Y AF Newville, M Cross, JO Ravel, B Sorensen, LB Bouldin, CE Yacoby, Y TI Co-refinement of diffraction anomalous fine-structure data SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 9th International Conference on X-Ray Absorption Fine Structure CY AUG 26-30, 1996 CL GRENOBLE, FRANCE SP European Synchrotron Radiat Facil, Ville Grenoble, Univ Joseph Fourier Grenoble, Minist Educ Natl, CNRS, CEA, Soc Francaise Chim, Jobin Yvon, Microcontrole, Eurisys Mesures, Inst Francais Petr, Air Liquide, Huber Diffrakt Teck, Haldor Topsoe A/S AB Diffraction Anomalous Fine-Structure (DAFS) combines the sensitivity to long-range-order of diffraction with the short-range-order sensitivity of XAFS. This makes it possible to use a set of DAFS measured intensities to simultaneously refine both long-and short-range structural parameters, while maintaining some constraints between them. This method combines a calculation of the structure factor based on the unit cell of the crystal with a calculation of the fine-structure chi(E) around each resonant site. Tabulated values of the scattering amplitude are used away from the resonant energies, while the near-edge anomalous scattering amplitude is calculated for the resonant sites using a differential Kramers-Kronig transform of an embedded atom absorption coefficient mu(0)(E) from FEFF. We discuss some of the subtleties of this approach to DAFS analysis. C1 USN,RES LAB,WASHINGTON,DC 20375. UNIV WASHINGTON,DEPT PHYS,SEATTLE,WA 98195. NIST,GAITHERSBURG,MD 20899. HEBREW UNIV JERUSALEM,RACAH INST PHYS,IL-91904 JERUSALEM,ISRAEL. RP Newville, M (reprint author), LAWRENCE LIVERMORE NATL LAB,L-219,LIVERMORE,CA 94550, USA. NR 4 TC 2 Z9 2 U1 0 U2 6 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD APR PY 1997 VL 7 IS C2 BP 759 EP 760 DI 10.1051/jp4:1997228 PN 2 PG 2 WC Physics, Multidisciplinary SC Physics GA XQ952 UT WOS:A1997XQ95200029 ER PT J AU Harris, VG Kemner, KM Das, BN Woicik, JC Crespo, P Hernando, A Escorial, AG AF Harris, VG Kemner, KM Das, BN Woicik, JC Crespo, P Hernando, A Escorial, AG TI Mechanical-alloying and lattice distortions in ball-milled CuFe SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 9th International Conference on X-Ray Absorption Fine Structure CY AUG 26-30, 1996 CL GRENOBLE, FRANCE SP European Synchrotron Radiat Facil, Ville Grenoble, Univ Joseph Fourier Grenoble, Minist Educ Natl, CNRS, CEA, Soc Francaise Chim, Jobin Yvon, Microcontrole, Eurisys Mesures, Inst Francais Petr, Air Liquide, Huber Diffrakt Teck, Haldor Topsoe A/S ID ABSORPTION FINE-STRUCTURE; FCC FE-CU; MAGNETIC-PROPERTIES AB Extended X-ray absorption fine structure (EXAFS) measurements were used to obtain element-specific, structural and chemical information of the local environments around Cu and Fe atoms in high-energy ball-milled samples. Analysis of the EXAFS data shows both Fe and Cu atoms reside in face-centered-cubic sites with the first coordination sphere consisting of a mixture of Fe and Cu atoms reflecting the as-prepared stoichiometry. The calculated bond distances indicate a dilation in the bonds between unlike neighbors which accounts for the lattice expansion measured by X-ray diffraction. C1 NIST,GAITHERSBURG,MD 20899. INST MAGNETISMO APLICADO,MADRID 28230,SPAIN. CSIC,CENIM,E-28040 MADRID,SPAIN. RP Harris, VG (reprint author), USN,RES LAB,WASHINGTON,DC 20375, USA. RI Harris, Vincent/A-8337-2009; Hernando, Antonio/E-2105-2015 NR 10 TC 3 Z9 3 U1 0 U2 1 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD APR PY 1997 VL 7 IS C2 BP 1151 EP 1152 DI 10.1051/jp4:19972168 PN 2 PG 2 WC Physics, Multidisciplinary SC Physics GA XQ952 UT WOS:A1997XQ95200169 ER PT J AU Harris, VG Kemner, KM Das, BN Woicik, JC Crespo, P Hernando, A Escorial, AG AF Harris, VG Kemner, KM Das, BN Woicik, JC Crespo, P Hernando, A Escorial, AG TI Mechanical-alloying and lattice distortions in ball-milled CuFe SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 9th International Conference on X-Ray Absorption Fine Structure CY AUG 26-30, 1996 CL GRENOBLE, FRANCE SP European Synchrotron Radiat Facil, Ville Grenoble, Univ Joseph Fourier Grenoble, Minist Educ Natl, CNRS, CEA, Soc Francaise Chim, Jobin Yvon, Microcontrole, Eurisys Mesures, Inst Francais Petr, Air Liquide, Huber Diffrakt Teck, Haldor Topsoe A/S ID ABSORPTION FINE-STRUCTURE; ELECTRON-YIELD; FE AB A least-square fitting analysis of EXAFS data collected From partially-crystallized Fe80B20 thin films (t=15 nm), using data collected from pure phase standards of the crystallization products, was found effective in determining the relative atomic fraction of each crystalline phase present. This fitting scheme provides a means for the quantitative treatment of crystallization and precipitation kinetics in thin films and multilayered structures. C1 NIST,GAITHERSBURG,MD 20899. INST MAGNETISMO APLICADO,MADRID 28230,SPAIN. CSIC,CENIM,E-28040 MADRID,SPAIN. RP Harris, VG (reprint author), USN,RES LAB,CODE 6342,WASHINGTON,DC 20375, USA. RI Harris, Vincent/A-8337-2009 NR 8 TC 1 Z9 1 U1 0 U2 0 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD APR PY 1997 VL 7 IS C2 BP 1153 EP 1154 DI 10.1051/jp4:19972169 PN 2 PG 2 WC Physics, Multidisciplinary SC Physics GA XQ952 UT WOS:A1997XQ95200170 ER PT J AU Liao, K Altkorn, RI Milkovich, SM Fildes, JM Gomez, J Schultheisz, CR Hunston, DL Brinson, LC AF Liao, K Altkorn, RI Milkovich, SM Fildes, JM Gomez, J Schultheisz, CR Hunston, DL Brinson, LC TI Long-term durability of glass-fiber reinforced composites in infrastructure applications SO JOURNAL OF ADVANCED MATERIALS LA English DT Article ID UNIDIRECTIONAL COMPOSITES; STRUCTURAL APPLICATIONS; FATIGUE PERFORMANCE; STRESS-CORROSION; PLASTICS AB Pultruded glass-fiber-reinforced composite coupons and I-beams were subjected to four-point bend environmental fatigue, freezing and thawing, and salt spraying in the laboratory to study their long-term durability for infrastructure applications. Specimens have survived to over 10 million cycles under four-point bend fatigue at 30 percent of the flexural strength in air without showing signs of degradation. However, preliminary results suggest that water and salt solutions are detrimental to the life of the material during long-term fatigue. Freezing and thawing in 2 percent (by mass) NaCl in water solution resulted in a decrease in dynamic modulus, flexural modulus, flexural strength, and toughness of the composite. Spraying composite I-beams and hybrid I-beams having carbon fiber outer layers with salt solution for nearly 1,300 hours at 19 degrees C has not changed their flexural moduli. Two composite structures in actual service were also monitored in addition to laboratory resting. Field data collected from an all-composite pedestrian bridge for over seven months does not suggest any change in its flexural modulus, and two composite walkway sections on a steel lift bridge have performed well in corrosion resistance since they were installed in November 1995. C1 VIRGINIA TRANSPORTAT RES COUNCIL,CHARLOTTESVILLE,VA. NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899. NORTHWESTERN UNIV,DEPT MECH ENGN,EVANSTON,IL 60208. RP Liao, K (reprint author), NORTHWESTERN UNIV,BASIC IND RES LAB,EVANSTON,IL 60201, USA. RI Brinson, L. Catherine/B-6678-2009; Brinson, L Catherine/B-1315-2013; Liao, Kin/A-7915-2014 OI Brinson, L Catherine/0000-0003-2551-1563; Liao, Kin/0000-0001-6352-2349 NR 62 TC 7 Z9 7 U1 0 U2 2 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 1070-9789 J9 J ADV MATER JI J. Adv. Mater. PD APR PY 1997 VL 28 IS 3 BP 54 EP 63 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA XK445 UT WOS:A1997XK44500008 ER PT J AU Blank, DHA Bijlsma, ME Moerman, R Rogalla, H Stork, FJB Roshko, A AF Blank, DHA Bijlsma, ME Moerman, R Rogalla, H Stork, FJB Roshko, A TI Surface roughness and height-height correlations dependence on thickness of YBaCuO thin films SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT Symposium on High Temperature Superconductor Thin Films - Growth Mechanisms, Interfaces, Multilayers, at the 1996 Spring Meeting of the European-Materials-Society CY JUN 04-07, 1996 CL STRASBOURG, FRANCE SP European Mat Res Soc DE surface roughness; superconductors; YBaCuO thin films AB For high T-c superconducting multilayer applications, smooth interfaces between the individual layers are required. However, in general, e.g., YBaCuO grows in a 3D screw-dislocation or island nucleation growth mode, introducing a surface roughness. In this contribution we study the surface layer roughness as a function of different deposition techniques as well as deposition parameters. Special attention will be paid to the increase in film roughness with increasing film thickness. For these studies we used scanning probe microscopy. From these experiments, we obtained an island density decreasing with a square root dependence on the film thickness. Furthermore, height-height correlations indicate that the him growth can be described by a ballistic growth process, with very limited effective surface diffusion. The correlation lengths xi are on the order of the island size, inferring that the island size forms the mean diffusion barrier. This results in a representation of non-correlated islands, which can be considered as autonomous systems. C1 NIST,BOULDER,CO. RP Blank, DHA (reprint author), UNIV TWENTE,POB 217,NL-7500 AE ENSCHEDE,NETHERLANDS. NR 7 TC 5 Z9 5 U1 2 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD APR PY 1997 VL 251 IS 1-2 BP 31 EP 33 DI 10.1016/S0925-8388(96)02765-X PG 3 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA XM340 UT WOS:A1997XM34000009 ER PT J AU Ayache, J Thorel, A LeDuigou, J Bonevich, J Dahmen, U AF Ayache, J Thorel, A LeDuigou, J Bonevich, J Dahmen, U TI Influence of the growth mechanism on the grain boundary structure in YBa2Cu3O7 thin film bicrystals SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT Symposium on High Temperature Superconductor Thin Films - Growth Mechanisms, Interfaces, Multilayers, at the 1996 Spring Meeting of the European-Materials-Society CY JUN 04-07, 1996 CL STRASBOURG, FRANCE SP European Mat Res Soc DE growth; grain boundary structure; YBa2Cu3O7 thin film bicrystals ID WEAK LINKS AB The growth control of thin YBa2Cu3O7 (YBCO) film bicrystals determines the quality of Josephson junctions and weak links. Previous TEM experiments on various thin him bicrystals showed grain boundary oscillations that were not clearly explained. We combined AFM, SEM, conventional TEM and HRTEM in order to perform a complete characterization of both substrate and YBa2Cu3O7 thin film bicrystals. Our results clearly show that the grain boundary oscillations are due to the YBCO growth mechanisms leading to a conflictual crystallographic situation at the grain boundary. The resulting crystallographic structure of the grain boundary may affect the interpretation of several recant experiments purporting to determine the nature of the HTC superconductivity. C1 ECOLE MINES PARIS,F-91003 EVRY,FRANCE. CNRS,LPS,F-92125 MEUDON,FRANCE. NATL INST STAND & TECHNOL,DIV MET,GAITHERSBURG,MD 20899. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,MSD,BERKELEY,CA 94720. RP Ayache, J (reprint author), CNRS,IN2P3,CSNSM,BAT 108,F-91405 ORSAY,FRANCE. NR 14 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD APR PY 1997 VL 251 IS 1-2 BP 78 EP 82 DI 10.1016/S0925-8388(96)02774-0 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA XM340 UT WOS:A1997XM34000019 ER PT J AU Prince, E Wilkinson, C McIntyre, GJ AF Prince, E Wilkinson, C McIntyre, GJ TI Comparison of the sigma(I)/I and least-squares methods for integration of Bragg reflections SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID DIFFRACTION DATA AB It is shown that peak integration by the sigma(I)/I method is equivalent to a least-squares method that uses a weight matrix W not equal V-y(-1), where V-y is the variance-covariance matrix of the observations. By the Gauss-Markov theorem, this gives variances for the estimated parameters that are greater, but in practice only slightly greater, than those obtained from an ideally weighted least-squares method. C1 NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899. EUROPEAN MOL BIOL LAB,F-38042 GRENOBLE,FRANCE. INST LAUE LANGEVIN,F-38042 GRENOBLE,FRANCE. RP Prince, E (reprint author), UNIV MARYLAND,DEPT MAT & NUCL ENGN,COLLEGE PK,MD 20742, USA. NR 12 TC 19 Z9 19 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD APR 1 PY 1997 VL 30 BP 133 EP 137 DI 10.1107/S0021889896012824 PN 2 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA WW377 UT WOS:A1997WW37700010 ER PT J AU Maddox, RA Howard, HW Dempsey, CL AF Maddox, RA Howard, HW Dempsey, CL TI Intense convective storms with little or no lightning over central Arizona: A case of inadvertent weather modification? SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID THUNDERSTORMS AB On 20/21 August 1993, deep convective storms occurred across much of Arizona, except for the southwestern quarter of the state. Several storms were quite severe, producing downbursts and extensive wind damage in the greater Phoenix area during the late afternoon and evening. The most severe convective storms occurred from 0000 to 0230 UTC 21 August and were noteworthy in that, except for the first reported severe thunderstorm, there was almost no cloud-to-ground (CG) lightning observed during their life cycles. Other intense storms on this day, particularly early storms to the south of Phoenix and those occurring over mountainous terrain to the north and east of Phoenix, were prolific producers of CG lightning. Radar data for an 8-h period (2000 UTC 20 August-0400 UTC 21 August) indicated that 88 convective cells having maximum reflectivities greater than 55 dBZ and persisting longer than 25 min occurred within a 200-km range of Phoenix. Of these cells, 30 were identified as ''low-lightning'' storms, that is, cells having three or fewer detected CG strikes during their entire radar-detected life cycle. The region within which the low-lightning storms were occurring spread to the north and east during the analysis period. Examination of the reflectivity structure of the storms using operational Doppler radar data from Phoenix, and of the supportive environment using upper-air sounding data taken at Luke Air Force Base just northwest of Phoenix, revealed no apparent physical reasons for the distinct difference in observed cloud-to-ground lightning character between the storms in and to the west of the immediate Phoenix area versus those to the north, east, and south. However, the radar data do reveal that several extensive clouds of chaff initiated over flight-restricted military ranges to the southwest of Phoenix. The prevailing flow advected the chaff clouds to the north and east. Convective storms that occurred in the area likely affected by the dispersing chaff clouds were characterized by little or no CG lightning. Field studies in the 1970s demonstrated that chaff injected into building thunderstorms markedly decreased CG lightning strikes. There are no data available regarding either the in-cloud lightning character of storms on this day or the technical specifications of the chaff being used in military aircraft anti-electronic warfare systems. However, it is hypothesized that this case of severe, but low-lightning, convective storms resulted from inadvertent lightning suppression over south-central Arizona due to an extended period of numerous chaff releases over the military ranges. RP Maddox, RA (reprint author), NOAA,ENVIRONM RES LAB,NATL SEVERE STORMS LAB,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. NR 14 TC 20 Z9 21 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 1997 VL 36 IS 4 BP 302 EP 314 DI 10.1175/1520-0450(1997)036<0302:ICSWLO>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV594 UT WOS:A1997WV59400003 ER PT J AU Reinking, RF Matrosov, SY Bruintjes, RT Martner, BE AF Reinking, RF Matrosov, SY Bruintjes, RT Martner, BE TI Identification of hydrometeors with elliptical and linear polarization K-a-band radar SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ICE CRYSTALS; CLOUDS AB Polarimetric radar can be used to identify various types of hydrometeors. Ice crystals of the varied growth habits depolarize and backscatter millimeter-wavelength radiation according to crystal aspect ratio, bulk density, and orientation, and the polarization state of the incident radiation. In this paper model calculations of the depolarization caused by various crystal types are extended from previous work, and K-a-band (8.66 mm) radar measurements of linear and elliptical depolarization ratios (LDR and EDR) from various ice hydrometeors are presented. The measurements for regular crystals are related to the models. Drizzle drops, which are quasi-spherical, serve as a reference. Signature discrimination in cloud systems with more than one type of hydrometeor is addressed. The model calculations illustrate the interplay of the parameters that control depolarization. They predict that in the depolarization signatures, crystals of the various basic planar and columnar habits should generally be most separable, one habit group from another and, to a degree, within each group when they occur in common, mature size distributions. It is verified in this and related papers that measurements of depolarization with a K-a-band dual-polarization radar provide good estimates of hydrometeor identity to separately distinguish drizzle, pristine crystals of various growth habits, graupel, and aggregates in winter storm clouds that have reasonable horizontal homogeneity over short distances (similar to 10-20 km). Characterization of the mix of two or three hydrometeor types is also possible, once the individual types are identified in some part of the cloud. Quantitative agreement between the measurements and the models, supported by snow crystal samples, was much better for EDR than for LDR; that is, EDR enabled more specific hydrometeor identification. However, LDR provided indications of randomness of crystal orientation and a wider decibel gap differentiating graupel from drizzle. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. NATL CTR ATMOSPHER RES,RES APPLICAT PROGRAM,BOULDER,CO 80307. RP Reinking, RF (reprint author), NOAA,ENVIRONM RES LAB,ENVIRONM TECHNOL LAB,R-E-ET6,325 BROADWAY,BOULDER,CO 80303, USA. NR 19 TC 18 Z9 19 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 1997 VL 36 IS 4 BP 322 EP 339 DI 10.1175/1520-0450(1997)036<0322:IOHWEA>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV594 UT WOS:A1997WV59400005 ER PT J AU Ryzhkov, A Zrnic, D Atlas, D AF Ryzhkov, A Zrnic, D Atlas, D TI Polarimetrically tuned R(Z) relations and comparison of radar rainfall methods SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID PRECIPITATION AB The following rainfall measurements are compared: 1) the reflectivity factor-rain rate or R(Z) relation, whereby the rain is estimated point by point for mapping or area integration; 2) use of a specific differential phase K-DP (between vertical and horizontal polarization) in a relation with rainfall rate for point-by-point mapping and subsequent integration over areas and time; 3) use of a R(K-DP) relation together with a relation between K-DP and Z to derive a polarimetrically tuned or matched R(Z) relation; and 4) use of empirical relations between the rainfall volume and the time integral of the storm area in which reflectivity is larger than a selected threshold. These methods are tested on five cases-two summer-type convections, one winter convective case, and two events of stratiform rain with embedded convection. Accumulations of rain in a dense gauge network in Oklahoma are used as a standard for comparison with radar measurements. In four of the five cases the rain totals obtained from the R(K-DP) relation agree very well with actual gauge accumulations. This is significantly better than the Marshall-Palmer R(Z) relation, which agrees well with gauges for only one event. Matching Z to K-DP brought the R(Z) derived rain total to better agreement with gauges in three more cases. C1 UNIV OKLAHOMA,COOPERAT INST MESOSCALE METEOROL STUDIES,NORMAN,OK 73019. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Ryzhkov, A (reprint author), NOAA,NATL SEVERE STORMS LAB,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. NR 20 TC 13 Z9 13 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 1997 VL 36 IS 4 BP 340 EP 349 DI 10.1175/1520-0450(1997)036<0340:PTRZRA>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV594 UT WOS:A1997WV59400006 ER PT J AU Grachev, AA Fairall, CW AF Grachev, AA Fairall, CW TI Dependence of the Monin-Obukhov stability parameter on the bulk Richardson number over the ocean SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ATMOSPHERIC SURFACE-LAYER; TURBULENT FLUXES; FREE-CONVECTION; BOUNDARY-LAYER; HEAT; INTERFACE; COEFFICIENTS; TEMPERATURE; ROUGHNESS; VELOCITY AB Recent measurements made onboard the R/P FLIP in the San Clemente Ocean Probing Experiment in September 1993 and onboard the R/V Moana Wave during Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment are used to evaluate the direct dependence between the Monin-Obukhov stability parameter (ratio of height to Obukhov length) zeta and the bulk Richardson number Ri(b) derived from standard meteorological mean observations of water surface temperature, wind speed, air temperature, and humidity. It is found that in the unstable marine surface layer, zeta = C Ri(b)(1 + Ri(b)/Ri(bc),)(-1), where the numerical coefficient C and the saturation Richardson number Ri(bc) are analytical functions of the standard bulk exchange coefficients. For measurements at a height of 10-15 m, C is about 10 and Ri(bc) is about -4.5. Their values are insensitive to variations of Ri(b) and zeta over three decades. Thus, a simple dependence between zeta and Ri(b) has a much wider range of applicability than previously believed. The authors show that this behavior is the result of the effects of ''gustiness'' driven by boundary layer-scale convective eddies. The derived relationship can be used as a first guess for zeta in bulk flux routines and reduces or eliminates the need for lengthy iterative solutions. Using this approximation yields errors in the latent heat flux of a few watts per square meter, compared to the full iterative solution. C1 INST ATMOSPHER PHYS, MOSCOW, RUSSIA. RP NOAA, ENVIRONM RES LAB, ENVIRONM TECHNOL LAB, R-E-ET7, 325 BROADWAY, BOULDER, CO 80303 USA. OI GRACHEV, ANDREY/0000-0002-7143-0820 NR 43 TC 52 Z9 53 U1 1 U2 6 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 1997 VL 36 IS 4 BP 406 EP 414 DI 10.1175/1520-0450(1997)036<0406:DOTMOS>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV594 UT WOS:A1997WV59400010 ER PT J AU Steele, KE AF Steele, KE TI Ocean current kinematic effects on pitch-roll buoy observations of mean wave direction and nondirectional spectra SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB The effects of ocean surface current Doppler frequency shifting on nondirectional spectra and mean wave direction are modeled. The model does not consider physical wave-current interactions. Model values for both ideal surface-following and 10-m-diameter discus hulls are computed. Unusual wave data reported by a 10-m-diameter discus buoy moored in a strong current in the eastern Gulf of Mexico are also analyzed using the model. Results indicate that the unusual characteristics of the measured data can be explained, at least in part, by the observations being made in a frame of reference (the buoy frame) in motion relative to that in which no ocean current would be observed (the frame moving with the current), provided hull response functions are included and reasonable current directions and speeds are assumed. RP Steele, KE (reprint author), NOAA,NATL DATA BUOY CTR,BAY ST LOUIS,MS 39529, USA. NR 15 TC 2 Z9 2 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 1997 VL 14 IS 2 BP 278 EP 291 DI 10.1175/1520-0426(1997)014<0278:OCKEOP>2.0.CO;2 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA WN718 UT WOS:A1997WN71800006 ER PT J AU Wilfong, TL Smith, SA Crosiar, CL AF Wilfong, TL Smith, SA Crosiar, CL TI Characteristics of high-resolution wind profiles derived from radar-tracked jimspheres and the rose processing program SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID UNIVERSAL SPECTRUM; WAVE SPECTRUM; STRATOSPHERE; ATMOSPHERE AB Results are presented from an investigation to estimate the limiting accuracy of atmospheric wind measurements obtained from a radar-tracked jimsphere and the data reduction program. The current system used to support space launches includes the jimsphere balloon, the radar, and the data processing system. Characteristics of the derived wind profiles are examined by spectral analysis of the radar tracking data and the derived wind profiles. Consistent with earlier work, the quality of the resulting wind profile is found to depend on the slant range of the balloon. In the current data processing systems, however, no explicit attempt is made to remove the effect of the regular oscillation of the jimsphere. The limiting accuracy of the system at low altitudes is found to be the result of aliased self-induced balloon motion in the wind profile. The magnitude of the error resulting from the aliased balloon oscillation decreases from 0.5 m s(-1) near the surface to near zero at about 12 km in proportion to the jimsphere rise rate. Radar noise adds to the errors in the wind profile and increases with slant range. For independent layer averages of about 30 m, the resulting accuracy is 0.5-0.7 m s(-1) in most tracking conditions. The effective vertical resolution of the system is found to increase in magnitude with altitude and slant range. Near the surface it is possible to resolve vertical features on the order of 150 m. At altitudes over 12 km at long slant ranges the effective vertical resolution decreases to 300 m. C1 LODI,NEW YORK,NY. RP Wilfong, TL (reprint author), SCI & TECHNOL CORP,NOAA,ETL,ET-4,325 BROADWAY,BOULDER,CO 80303, USA. NR 23 TC 8 Z9 8 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 1997 VL 14 IS 2 BP 318 EP 325 DI 10.1175/1520-0426(1997)014<0318:COHRWP>2.0.CO;2 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA WN718 UT WOS:A1997WN71800009 ER PT J AU Anthony, EB Schade, W Bastian, MJ Bierbaum, VM Leone, SR AF Anthony, EB Schade, W Bastian, MJ Bierbaum, VM Leone, SR TI Laser probing of velocity-subgroup dependent rotational alignment of N-2(+) drifted in He SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INDUCED FLUORESCENCE MEASUREMENTS; COLLISIONAL ALIGNMENT; HYPERFINE-STRUCTURE; PHOTOFRAGMENT ALIGNMENT; MOLECULAR ROTATION; DISTRIBUTIONS; ORIENTATION; POLARIZATION; POPULATION; TRANSPORT AB Results are presented for Doppler-resolved laser-induced fluorescence measurements of collision-induced rotational alignment of N-2(+)(v ''=0) drifted in He in a drift-tube apparatus. A single-frequency ring dye laser is used to probe the R(1)(N ''=15) rotational line of the B (2) Sigma(u)(+)-X (2) Sigma(g)(+) system both parallel and perpendicular to the drift field at three different field strengths and at several different Doppler-selected velocities. A strong correlation is found between the degree of rotational alignment and the velocity subgroup probed along the field direction. For field strengths of 8 and 16 Td and laser probe parallel to the drift field, there is a monotonic increase in the quadrupole alignment parameter A(2) With higher velocity subgroup, up to a maximum value of A(0)((2)) = -0.150 (6) for 16 Td at the high-velocity tail. There is evidence that the correlation between alignment and velocity increases with increasing field strength. The mechanisms of the alignment are discussed and these results are attributed primarily to the change in anisotropy of the relative velocity vector distribution of the N-2(+)-He pair with field strength. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. CHRISTIAN ALBRECHTS UNIV KIEL,INST PHYS EXPT,D-24098 KIEL,GERMANY. RP Anthony, EB (reprint author), UNIV COLORADO,NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,DEPT PHYS,BOULDER,CO 80309, USA. NR 43 TC 26 Z9 26 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 1997 VL 106 IS 13 BP 5413 EP 5422 DI 10.1063/1.473604 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WP839 UT WOS:A1997WP83900009 ER PT J AU Thiebaux, HJ AF Thiebaux, HJ TI The power of the duality in spatial-temporal estimation SO JOURNAL OF CLIMATE LA English DT Article ID MULTIVARIATE AB Space-time filtering has a long and often confusing history in the geosciences. it is called by different names in different areas of geoscience, where numerous applications have been developed. The variety of notations that have emerged adds to this confusion. A unified treatment of spatial-temporal estimation is presented, which highlights its duality and the associated trade-off in the construction of any optimal estimation algorithm. The duality in optimal estimation comes from the requirement that the representation of the spatial-temporal statistical structure of the increments between the true field and the system-operator model used by the filter be matched with the true ensemble structure of the increment field. The associated trade-off arises from the following dichotomy: the closer the system-operator model corresponds to the true system operator, the less ensemble structure remains in the increment field. Conversely, the simpler the model of the system operator, the more residual statistical structure remains to be represented. Several examples of estimation of spatial-temporal systems, in practice, are presented to illustrate the power of the duality. The rationale for determining the placement of effort in modeling the system operator vis-a-vis representing residual statistical structure is discussed. RP Thiebaux, HJ (reprint author), NOAA,NATL WEATHER SERV,NATL CTR ENVIRONM PREDICT,CTR ENVIRONM MODELING,DEPT COMMERCE,CAMP SPRINGS,MD 20746, USA. NR 11 TC 10 Z9 10 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 1997 VL 10 IS 4 BP 567 EP 573 DI 10.1175/1520-0442(1997)010<0567:TPOTDI>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV718 UT WOS:A1997WV71800003 ER PT J AU Zhang, RH Levitus, S AF Zhang, RH Levitus, S TI Structure and cycle of decadal variability of upper-ocean temperature in the North Pacific SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; CLIMATE VARIABILITY; INTERDECADAL VARIABILITY; ATLANTIC OCEAN; HEAT-FLUX; MODEL; INTERMEDIATE; ANOMALIES; SALINITY; SCALES AB Yearly upper-ocean in situ temperature anomaly data for the period 1961-90 are analyzed to reveal spatial structure and evolution of decadal variability in the North Pacific Ocean. An EOF analysis has been performed on individual temperature anomaly fields at upper-ocean standard levels, as well as simultaneously on the entire upper-ocean data to depict the combined three-dimensional structure in a coherent manner Time evolution of anomaly fields is depicted by using a regression analysis. The analyses detect the principal basin-scale structure of decadal warm period (DCVP) and decadal cold period (DCP). There is a well-defined subsurface thermal anomaly pattern, characterized by a prominent seesaw structure with opposite anomaly polarity between the midlatitude North Pacific and the subtropical regions. During a DWP, a positive temperature anomaly is found in the central midlatitude upper ocean, with the maximum at about 100-m depth. This is accompanied by a corresponding negative anomaly in the American coastal region and in the subtropics. A reverse pattern of these anomalies is observed during the DCP. Evolution between the DWP and the DCP involves significant zonal and meridional propagation of anomaly phase around the North Pacific, showing consistent and coherent variations from subsurface to sea surfacer from central midlatitudes to the American coastal regions, and to the subtropical Pacific Ocean. This phase propagation is much more well-organized at subsurface depths than that at the sea surface, suggesting an anomaly decadal-scale cycle circulating clockwise around the subtropical gyre, which supports earlier findings by Latif and Barnett. There is a systematic and coherent westward transpacific phase propagation in the subtropical region. These analyses present evidence of the manner in which upper-ocean temperature anomalies evolved in the North Pacific, thus providing an observational basis for evaluating theoretical studies and model simulations. The dynamical implication for physical understanding and prediction of decadal climate Variability are discussed. C1 NOAA,NATL OCEANOG DATA CTR,OCEAN CLIMATE LAB,SILVER SPRING,MD. NR 35 TC 96 Z9 112 U1 3 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 1997 VL 10 IS 4 BP 710 EP 727 DI 10.1175/1520-0442(1997)010<0710:SACODV>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV718 UT WOS:A1997WV71800013 ER PT J AU Vitart, F Anderson, JL Stern, WF AF Vitart, F Anderson, JL Stern, WF TI Simulation of interannual variability of tropical storm frequency in an ensemble of GCM integrations SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; HURRICANE-TYPE VORTICES; EXISTING CLIMATE MODELS; CYCLONE ACTIVITY; ANTHROPOGENIC CHANGES; SOUTHERN-OSCILLATION; SPECTRAL MODEL; ATLANTIC BASIN; EL-NINO; FORECASTS AB The present study examines the simulation of the number of tropical storms produced in GCM integrations with a prescribed SST A g-member ensemble of IO-yr integrations (1979-88) of a T42 atmospheric model forced by observed SSTs has been produced; each ensemble member differs only in the initial atmospheric conditions. An objective procedure for tracking-model-generated tropical storms is applied to this ensemble during the last 9 yr of the integrations (1980-88). The seasonal and monthly variations of tropical storm numbers are compared with observations for each ocean basin. Statistical tools such as the Chi-square test, the F test, and the t test are applied to the ensemble number of tropical storms, leading to the conclusion that the potential predictability is particularly strong over the western North Pacific and the eastern North Pacific, and to a lesser extent over the western North Atlantic. A set of tools including the joint probability distribution and the ranked probability score are used to evaluate the simulation skill of this ensemble simulation. The simulation skill over the western North Atlantic basin appears to be exceptionally high, particularly during years of strong potential predictability. C1 PRINCETON UNIV,PROGRAM ATMOSPHER & OCEAN SCI,PRINCETON,NJ 08544. RP Vitart, F (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,POB 308,PRINCETON,NJ 08542, USA. NR 58 TC 96 Z9 100 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 1997 VL 10 IS 4 BP 745 EP 760 DI 10.1175/1520-0442(1997)010<0745:SOIVOT>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV718 UT WOS:A1997WV71800015 ER PT J AU MacKay, RM Ko, MKW Shia, RL Yang, YJ Zhou, ST Molnar, G AF MacKay, RM Ko, MKW Shia, RL Yang, YJ Zhou, ST Molnar, G TI An estimation of the climatic effects of stratospheric ozone losses during the 1980s SO JOURNAL OF CLIMATE LA English DT Article ID DYNAMICAL HEAT FLUXES; ENERGY-BALANCE; MODEL; ATMOSPHERE; PARAMETERIZATION; SENSITIVITY; TEMPERATURE; OCEAN; CO2; O-3 AB In order to study the potential climatic effects of the ozone hole more directly and to assess the validity of previous lower resolution model results, the latest high spatial resolution version of the Atmospheric and Environmental Research, Inc., seasonal radiative dynamical climate model is used to simulate the climatic effects of ozone changes relative to the other greenhouse gases. The steady-state climatic effect of a sustained decrease in lower stratospheric ozone, similar in magnitude to the observed 1979-90 decrease, is estimated by comparing three steady-state climate simulations: I) 1979 greenhouse gas concentrations and 1979 ozone, II) 1990 greenhouse gas concentrations with 1979 ozone, and III) 1990 greenhouse gas concentrations with 1990 ozone. The simulated increase in surface air temperature resulting from nonozone greenhouse gases is 0.272 K. When changes in lower stratospheric ozone are included, the greenhouse warming is 0.165 K, which is approximately 39% lower than when ozone is fixed at the 1979 concentrations. Ozone perturbations at high latitudes result in a cooling of the surface-troposphere system that is greater (by a factor of 2.8) than that estimated from the change in radiative forcing resulting from ozone depletion and the model's 2 x CO2 climate sensitivity. The results suggest that changes in meridional heat transport from low to high latitudes combined with the decrease in the infrared opacity of the lower stratosphere are Very important in determining the steady-state response to high latitude ozone losses. The 39% compensation in greenhouse warming resulting from lower stratospheric ozone losses is also larger than the 28% compensation simulated previously by the lower resolution model. The higher resolution model is able to resolve the high latitude features of the assumed ozone perturbation, which are important in determining the overall climate sensitivity to these perturbations. C1 ATMOSPHER & ENVIRONM RES INC,CAMBRIDGE,MA 02139. NATL CTR ENVIRONM PREDICT,WASHINGTON,DC. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI Ko, Malcolm/D-5898-2015 NR 39 TC 11 Z9 11 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 1997 VL 10 IS 4 BP 774 EP 788 DI 10.1175/1520-0442(1997)010<0774:AEOTCE>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV718 UT WOS:A1997WV71800017 ER PT J AU Li, TM Philander, SGH AF Li, TM Philander, SGH TI On the seasonal cycle of the equatorial Atlantic Ocean SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; MODEL AB Although the seasonal cycle of the equatorial Atlantic and Pacific Oceans have many similarities, for example, an annual signal is dominant at the equator even though the sun ''crosses'' the equator twice a year, different processes determine the seasonal cycles of the two oceans and in the Atlantic different processes are important in the east and west. In the Gulf of Guinea in the eastern equatorial Atlantic, the seasonal cycle of surface winds is primarily in response to seasonal variations in land temperatures so that annual changes in sea surface temperatures are, to a first approximation, the passive response of the ocean to the winds. The seasonal cycle of the western equatorial Atlantic has similarities with that of the equatorial Pacific-both are strongly influenced by ocean-atmosphere interactions in which the surface winds and sea surface temperature patterns depend on each other-but only in the western equatorial Atlantic are the seasonal variations in sea surface temperature influenced by vertical excursions of the thermocline. These results are obtained by means of a general circulation model of the atmosphere and a relatively simple coupled ocean-atmosphere model. C1 PRINCETON UNIV,ATMOSPHER & OCEAN SCI PROGRAM,PRINCETON,NJ 08544. NR 11 TC 39 Z9 39 U1 1 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 1997 VL 10 IS 4 BP 813 EP 817 DI 10.1175/1520-0442(1997)010<0813:OTSCOT>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV718 UT WOS:A1997WV71800020 ER PT J AU Braun, RJ Murray, BT AF Braun, RJ Murray, BT TI Adaptive phase-field computations of dendritic crystal growth SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 10th American Conference on Crystal Growth/9th International Conference on Vapor Growth and Epitaxy CY AUG 04-09, 1996 CL VAIL, CO ID MODEL; INTERFACE; SOLIDIFICATION; SIMULATIONS AB Phase-field models have been the subject of much interest in the last several years for the investigation of phase transitions with complicated morphology, such as dendritic growth. The phase-field method introduces a continuous transition between the two phases across a thin layer of finite thickness; the advantage of this approach is that the location of the interface does not have to be explicitly determined as part of the solution but is obtained from the solution of an additonal field equation representing the evolution of the phase-field variable over the entire domain. A brief overview is presented of the phase-field model development for a pure material using irreversible thermodynamics. The computational model includes four-fold anisotropy both in surface energy and interfacial kinetics. Numerical solutions are obtained using a general-purpose adaptive finite-difference algorithm. Adaptivity in space and time is found to extend somewhat the parameter regime where computations can be carried out. Good convergence to sharp-interface models is achieved for dimensionless undercoolings of 0.25, but a relatively small amount of solid phase grows before the thermal field is affected by the size of the computational domain. Further progress to smaller undercoolings will have to be aided by more sophisticated modeling. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Braun, RJ (reprint author), UNIV DELAWARE,DEPT MATH SCI,501 EWING HALL,NEWARK,DE 19716, USA. NR 33 TC 67 Z9 70 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 1997 VL 174 IS 1-4 BP 41 EP 53 DI 10.1016/S0022-0248(96)01059-7 PG 13 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA XJ186 UT WOS:A1997XJ18600008 ER PT J AU Roshko, A Stork, FJB Rudman, DA Aldrich, DJ Hotsenpiller, PAM AF Roshko, A Stork, FJB Rudman, DA Aldrich, DJ Hotsenpiller, PAM TI Comparison of heteroepitaxial YBa2Cu3O7-delta and TiO2 thin film growth SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 10th American Conference on Crystal Growth/9th International Conference on Vapor Growth and Epitaxy CY AUG 04-09, 1996 CL VAIL, CO DE film growth; heteroepitaxy; rutile; YBCO; growth mechanism; scanning probe microscopy ID SCANNING-TUNNELING-MICROSCOPY; TRANSMISSION ELECTRON-MICROSCOPY; SCREW DISLOCATIONS; ATOMIC-FORCE; MICROSTRUCTURE; MECHANISM; EVOLUTION AB The growth of heteroepitaxial YBa2Cu3O7-delta and TiO2 thin films has been investigated as a function of deposition rate, film thickness, and deposition temperature. In spite of the fact that the two materials are grown at very different rates and undercoolings, the films are found to have similar growth mechanisms and dependences on film thickness and deposition temperature. Both types of films were found to have an island growth morphology, as shown by STM and AFM. The diameter of the islands was found to increase with the film thickness through a power law dependence. It is shown that this is not the result of a grain growth mechanism, but is consistent with that predicted for a coarsening mechanism. The density of the islands decreased exponentially with increasing substrate temperature. The temperature dependence is consistent With those of homogeneous nucleation and of a diffusion-controlled process. The similar characteristics of the films of these two different materials suggest that YBa2Cu3O7-delta may be useful as a model system for studying heteroepitaxial oxide film growth. C1 DUPONT CO INC, WILMINGTON, DE USA. RP UNIV COLORADO, NIST, JOINT INST LAB ASTROPHYS, 325 BROADWAY, BOULDER, CO 80309 USA. NR 35 TC 14 Z9 14 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 EI 1873-5002 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 1997 VL 174 IS 1-4 BP 398 EP 408 DI 10.1016/S0022-0248(96)01135-9 PG 11 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA XJ186 UT WOS:A1997XJ18600063 ER PT J AU Hotsenpiller, PAM Roshko, A Lowekamp, JB Rohrer, GS AF Hotsenpiller, PAM Roshko, A Lowekamp, JB Rohrer, GS TI Growth morphologies of heteroepitaxial rutile films on sapphire substrates SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 10th American Conference on Crystal Growth/9th International Conference on Vapor Growth and Epitaxy CY AUG 04-09, 1996 CL VAIL, CO DE titanium dioxide; rutile; films; epitaxy; morphologies; growth; sputtering; MOCVD ID IONIZED CLUSTER BEAM; CHEMICAL-VAPOR-DEPOSITION; EPITAXIAL TIO2 FILMS; THIN-FILMS; MOCVD AB The growth morphologies of (100), (101) and (001) rutile films grown on sapphire substrates by the ion-beam sputter deposition technique have been examined as a function of film/substrate orientation, film thickness, substrate surface preparation, growth rate and growth temperature. The rutile films of each orientation appear to grow via island (Volmer-Weber) type growth. Al the early stages of growth (less than or equal to 100 Angstrom) on as-polished substrates, the roughnesses of the films grown at 725 degrees C and 3 Angstrom/min are correlated to their lattice mismatches and inversely related to the calculated surface energies of their sapphire substrates. Thicker films (greater than or equal to 700 Angstrom) have morphologies which are orientation dependent, appear to minimize their surface energies and are stable with respect to annealing. Rougher and slightly less crystallographically aligned (100) and (001) rutile films result from the more three-dimensional growth found on annealed sapphire substrates. Relatively small increases in the growth rate, at very low rates, can change the details of the surface structures present. The changes in the morphologies observed on films grown at lower temperatures indicate that the processes controlling their development have a strong temperature dependence at all stages. Comparisons were also made between (100) and (101) rutile films grown by the ion-beam sputter deposition and metalorganic chemical vapor deposition techniques under similar conditions. The chemical vapor deposited films have morphologies which are similar to the ion-beam sputtered films with comparable thicknesses, but grown al lower temperatures. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. CARNEGIE MELLON UNIV,DEPT MAT SCI & ENGN,PITTSBURGH,PA 15213. RP Hotsenpiller, PAM (reprint author), DUPONT CO INC,EXPT STN,WILMINGTON,DE 19880, USA. RI Rohrer, Gregory/A-9420-2008 OI Rohrer, Gregory/0000-0002-9671-3034 NR 22 TC 19 Z9 21 U1 1 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 1997 VL 174 IS 1-4 BP 424 EP 433 DI 10.1016/S0022-0248(96)01138-4 PG 10 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA XJ186 UT WOS:A1997XJ18600066 ER PT J AU Sekerka, RF Coriell, SR McFadden, GB AF Sekerka, RF Coriell, SR McFadden, GB TI Stagnant film model of the effect of natural convection on the dendrite operating state (vol 154, pg 370, 1995) SO JOURNAL OF CRYSTAL GROWTH LA English DT Correction, Addition C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. CARNEGIE MELLON UNIV,DEPT MATH & PHYS,PITTSBURGH,PA 15213. RI McFadden, Geoffrey/A-7920-2008 OI McFadden, Geoffrey/0000-0001-6723-2103 NR 1 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 1997 VL 173 IS 3-4 BP 597 EP 597 DI 10.1016/S0022-0248(96)01065-2 PG 1 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA XC981 UT WOS:A1997XC98100045 ER PT J AU Garris, MD Blue, JL Candela, GT Dimmick, DL Geist, J Grother, PJ Janet, SA Omidvar, OM Wilson, CL AF Garris, MD Blue, JL Candela, GT Dimmick, DL Geist, J Grother, PJ Janet, SA Omidvar, OM Wilson, CL TI Design of a handprint recognition system SO JOURNAL OF ELECTRONIC IMAGING LA English DT Article AB A public domain optical character recognition (OCR) system has been developed by the National institute of Standards and Technology (NIST). This standard reference form-based handprint recognition system is designed to provide a baseline of performance on an open application. The system's source code, training data, performance assessment tools, and type of forms processed are all publicly available. The system is modular, allowing for system component testing and comparisons, and it can be used to validate training and testing sets in an end-to-end application. The system's source code is written in C and will run on virtually any UNIX-based computer. The presented functional components of the system are divided into three levels of processing: (1) form-level processing in eludes the tasks of form registration and form removal; (2) field-level processing includes the tasks of field isolation, line trajectory reconstruction, and field segmentation; and (3) character-level processing includes character normalization, feature extraction, character classification, and dictionary-based postprocessing. The system contains a number of significant contributions to OCR technology, in eluding an optimized probabilistic neural network (PNN) classifier that operates a factor of 20 times faster than traditional software implementations of the algorithm. Provided in the system are a host of data structures and low-level utilities for computing spatial histo grams, least-squares fitting, spatial zooming, connected components, Karhunen Loeve feature extraction, optimized PNN classification, and dynamic string alignment. Any portion of this standard reference OCR system can be used in commercial products without restrictions, (C) 1997 SPIE and IS&T. [S1017-9909(97)00502-3]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Garris, MD (reprint author), Natl Inst Stand & Technol, Bldg 225,Room A216, Gaithersburg, MD 20899 USA. NR 28 TC 0 Z9 0 U1 0 U2 0 PU I S & T - SOC IMAGING SCIENCE TECHNOLOGY PI SPRINGFIELD PA 7003 KILWORTH LANE, SPRINGFIELD, VA 22151 USA SN 1017-9909 J9 J ELECTRON IMAGING JI J. Electron. Imaging PD APR PY 1997 VL 6 IS 2 BP 231 EP 243 DI 10.1117/12.266865 PG 13 WC Engineering, Electrical & Electronic; Optics; Imaging Science & Photographic Technology SC Engineering; Optics; Imaging Science & Photographic Technology GA ZY364 UT WOS:000074613400008 ER PT J AU Albus, JS AF Albus, JS TI The NIST Real-time Control System (RCS): An approach to intelligent systems research SO JOURNAL OF EXPERIMENTAL & THEORETICAL ARTIFICIAL INTELLIGENCE LA English DT Article AB Differences between the deliberative and reactive aspects of behaviour have led to different scientific approaches that have divided the field of cognitive research for at least a century. In the tradition of the behaviourist school of psychology, many present day researchers in advanced robotics and artificial intelligence have abandoned inquiry into the complexities of cognitive behaviour in favour of a minimalist philosophy that focuses primarily on stimulus-response reactivity. In contrast, the Real-time Control System (RCS) developed at NIST and elsewhere over the past two decades provides a model for bridging the gap between deliberative and reactive behaviours. RCS is a reference model architecture for intelligent systems design that consists of a hierarchically layered set of processing nodes. In each node, there are both cognitive and reactive elements. At each layer, entities are recognized, tasks are deliberatively planned, and feedback from sensors closes a reactive control loop. RCS thus integrates and distributes deliberative and reactive functions throughout the entire hierarchical architecture, at all levels and time frames. A comparison is made between RCS and subsumption and some illustrative examples of RCS applications are given. C1 NATL INST STAND & TECHNOL,INTELLIGENT SYST DIV,GAITHERSBURG,MD 20895. NR 22 TC 20 Z9 20 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0952-813X J9 J EXP THEOR ARTIF IN JI J. Exp. Theor. Artif. Intell. PD APR-SEP PY 1997 VL 9 IS 2-3 BP 157 EP 174 DI 10.1080/095281397147059 PG 18 WC Computer Science, Artificial Intelligence SC Computer Science GA XA328 UT WOS:A1997XA32800003 ER PT J AU Wagner, C Klokocnik, J Cheney, R AF Wagner, C Klokocnik, J Cheney, R TI Making the connection between Geosat and TOPEX/Poseidon SO JOURNAL OF GEODESY LA English DT Article ID PRECISION ORBIT DETERMINATION; ERS-1 CROSSOVER ALTIMETRY; ACCURACY; MODEL AB We can presently construct two independent time series of sea level, each at a precision of a few centimeters, from Geosat (1985-1988) and TOPEX/Poseidon (1992-1995) collinear altimetry. Both are based on precise satellite orbits computed using a common geopotential model, JGM-2 (Nerem et al. 1994). We have attempted to connect these series using Geosat-T/P crossover differences in order to assess long-term ocean changes between these missions. Unfortunately, the observed result are large-scale sea level differences which appear to be due to a combination of geodetic and geopotential error sources. The most significant geodetic component seems to be a coordinate system bias for Geosat sea level (relative to T/P) of -7 to -9 cm in the y-axis (towards the Eastern Pacific). The Geosat-T/P sea height differences at crossovers (with JGM-2 orbits) probably also contain stationary geopotential-orbit error of about the same magnitude which also distort any oceanographic interpretation of the observed changes. We also found JGM-3 Geosat orbits have not resolved the datum errors evident from the JGM-2 Geosat-T/P results. We conclude that the direct altimetric approach to accurate determination of sea level change using Geosat and T/P data still depends on further improvement in the Geosat orbits, including definition of the geocenter. C1 ACAD SCI CZECH REPUBL,INST ASTRON,CZ-25165 ONDREJOV,CZECH REPUBLIC. RP Wagner, C (reprint author), NOAA,GEOSCI LAB,SILVER SPRING,MD 20910, USA. RI Klokocnik, Jaroslav/G-9025-2014 NR 23 TC 8 Z9 8 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0949-7714 J9 J GEODESY JI J. Geodesy PD APR PY 1997 VL 71 IS 5 BP 273 EP 281 DI 10.1007/s001900050095 PG 9 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA XB287 UT WOS:A1997XB28700003 ER PT J AU Buonsanto, MJ Codrescu, M Emery, BA Fesen, CG FullerRowell, TJ MelendezAlvira, DJ Sipler, DP AF Buonsanto, MJ Codrescu, M Emery, BA Fesen, CG FullerRowell, TJ MelendezAlvira, DJ Sipler, DP TI Comparison of models and measurements at Millstone Hill during the January 24-26, 1993, minor storm interval SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID GENERAL-CIRCULATION MODEL; HIGH-LATITUDE IONOSPHERE; COLLISION CROSS-SECTION; PEAK ELECTRON-DENSITY; O+-O; THERMOSPHERIC DYNAMICS; GEOMAGNETIC STORM; F-REGION; AERONOMICAL MEASUREMENTS; SEPTEMBER 18-19 AB Results from four first-principle models are compared with Millstone Hill incoherent scatter radar and Fabry-Perot interferometer measurements taken during January 24-26, 1993, a period which included a minor geomagnetic storm. The models used in this study are the thermosphere ionosphere electrodynamics general circulation model (TIEGCM) with and without forcings from the assimilative mapping of ionospheric electrodynamics (AMIE) technique, the coupled thermosphere ionosphere model (CTIM), and the field line interhemispheric plasma (FLIP) model. The present study is the first time the AMIE inputs have been used in the TIEGCM model. TIEGCM and CTIM both underestimate the neutral temperature because of an underestimation of the Joule heating rate. An increase in the high latitude Joule heating would modify the thermospheric circulation. This could result in increases in N-2 and O-2 density above Millstone Hill, which would decrease the AMIE TIEGCM peak electron density (NmF(2)) to agree better with the observations, but would result in poorer agreement between CTIM and the data. The FLIP model NmF is a little low compared to the data, perhaps because of an inadequacy of the mass spectrometer incoherent scatter (MSIS) 86 model composition or the H+ flux in the model. Good agreement is obtained between atomic oxygen density [O] given by MSIS and [O] obtained from the radar data using a heat balance equation, provided an O+-O collision frequency factor of 1.3 is used. While the TIEGCM underestimates the electron and ion temperatures, the FLIP model reproduces major features of the data, apart from a large nighttime enhancement in T-e. During the minor storm interval the observed neutral winds show alternating equatorward surges and abatements apparently due to passage of traveling atmospheric disturbances (TADs) seen in the model results. These are associated with a late evening increase observed in NmF(2) accompanied by a large increase in F-2 peak height (hmF(2)). These perturbations in NmF(2) and hmF(2) are not reproduced by the TIEGCM or CTIM. The NmF2 increase may be due to a decrease in O+ recombination rate caused by the higher hmF(2), combined with compressional effects of a TAD and an enhanced downward flux of O+ ions. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. NATL CTR ATMOSPHER RES, HIGH ALTITUDE OBSERV, BOULDER, CO 80307 USA. USN, RES LAB, EO HULBURT CTR SPACE RES, WASHINGTON, DC 20375 USA. NOAA, SPACE ENVIRONM CTR, BOULDER, CO USA. DARTMOUTH COLL, DEPT PHYS & ASTRON, HANOVER, NH 03755 USA. RP MIT, HAYSTACK OBSERV, WESTFORD, MA 01886 USA. NR 66 TC 60 Z9 60 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1997 VL 102 IS A4 BP 7267 EP 7277 DI 10.1029/96JA02602 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WR367 UT WOS:A1997WR36700023 ER PT J AU Flaud, JM Betrencourt, M Arcas, P Burger, H Polanz, O Lafferty, WJ AF Flaud, JM Betrencourt, M Arcas, P Burger, H Polanz, O Lafferty, WJ TI Simultaneous analysis of the 2 nu(2), nu(1), and nu v(3) bands of hydrogen telluride SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article AB Spectra of a natural sample of hydrogen telluride as well as a spectrum of monoisotopic H-2 Te-130 have been recorded by means of Fourier transform spectrometry with a resolution of 0.003 cm(-1) in the spectral domain 7.5-4.3 mu m where it is easy to observe the main absorbing bands nu(1) and nu(3). We have located and assigned for the first time the 2 nu(2) band which appears in the lower wavenumber range of the recorded spectral domain near 1700 cm(-1). It proved necessary to treat simultaneously the three states (020), (100), and (001), nu(1) and nu(3) are indeed Coriolis-coupled vibration-rotation bands and it was observed that a few rotational levels of (001) could not be fitted to within their experimental accuracy without considering the second-order Coriolis interaction between the rotational levels of (020) and (001). In this way all the experimental levels were calculated to within the experimental uncertainty, and precise sets of vibrational energies and rotational and coupling constants were obtained for the seven most abundant H2Te isotopic species, namely H-2 Te-130, H-2 Te-128, H-2 Te-126, H-2 Te-125, H-2 Te-124, H-2 Te-123, and H-2 Te-122. For the most abundant isotopic species H-2 Te-130 the bands centers are nu(0)(2 nu(2)) = 1715.9568, nu(0)(v(1)) = 2065.2709, nu(0)(nu(3)) = 2072.1101 cm(-1). (C) 1997 Academic Press. C1 UNIV PARIS 06,LAB PHYS MOL & APPLICAT,F-91405 ORSAY,FRANCE. BERG UNIV GESAMTHSCH WUPPERTAL,FB9,D-42097 WUPPERTAL,GERMANY. NATL INST STAND & TECHNOL,DIV MOL PHYS,GAITHERSBURG,MD 20899. RP Flaud, JM (reprint author), UNIV PARIS 11,CNRS,LAB PHYS MOL & APPLICAT,BAT 350,F-91405 ORSAY,FRANCE. NR 7 TC 6 Z9 6 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD APR PY 1997 VL 182 IS 2 BP 396 EP 420 DI 10.1006/jmsp.1996.7213 PG 25 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA WT456 UT WOS:A1997WT45600016 ER PT J AU Treguier, AM Held, IM Larichev, VD AF Treguier, AM Held, IM Larichev, VD TI Parameterization of quasigeostrophic eddies in primitive equation ocean models SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID GENERAL-CIRCULATION; POTENTIAL VORTICITY; NORTH-ATLANTIC; EDDY; TRANSPORTS; FLOWS AB A parameterization of mesoscale eddy fluxes in the ocean should be consistent with the fact that the ocean interior is nearly adiabatic. Gent and McWilliams have described a framework in which this can be approximated in L-coordinate primitive equation models by incorporating the effects of eddies on the buoyancy field through an eddy-induced velocity. It is also natural to base a parameterization on the simple picture of the mixing of potential vorticity in the interior and the mixing of buoyancy at the surface. The authors discuss the various constraints imposed by these two requirements and attempt to clarify the appropriate boundary conditions on the eddy-induced velocities at the surface. Quasigeostrophic theory is used as a guide to the simplest way of satisfying these constraints. C1 PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,PRINCETON,NJ 08542. PRINCETON UNIV,AOS PROGRAM,PRINCETON,NJ 08544. RP Treguier, AM (reprint author), IFREMER,LPO,BP70,F-29280 PLOUZANE,FRANCE. RI Treguier, Anne Marie/B-7497-2009 OI Treguier, Anne Marie/0000-0003-4569-845X NR 35 TC 175 Z9 175 U1 0 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD APR PY 1997 VL 27 IS 4 BP 567 EP 580 DI 10.1175/1520-0485(1997)027<0567:POQEIP>2.0.CO;2 PG 14 WC Oceanography SC Oceanography GA WT536 UT WOS:A1997WT53600006 ER PT J AU Balmer, ML Huang, Q WongNg, W Roth, RS Santoro, A AF Balmer, ML Huang, Q WongNg, W Roth, RS Santoro, A TI Neutron and X-ray diffraction study of the crystal structure of CsTiSi2O6.5 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article AB The structure of the silicotitanate CsTiSi2O6.5 has been analyzed with neutron powder and X-ray single crystal diffraction techniques. The compound crystallizes with the symmetry of space group Ia (3) over bar d and lattice parameter a = 13.8417(7) Angstrom. There are 16 formula units in the unit cell, The basic structure of the silicotitanate is similar to that of pollucite and consists of a framework of corner-sharing TO4 tetrahedra (T = 1/3 Ti+ 2/3 Si) forming large voids in which the Cs+ cations are located. Titanium and silicon are disordered over the 48g sites of the cubic space group. Compared to pollucite, there are eight extra oxygen atoms in the unit cell. These atoms partially occupy two sets of general sites and are bonded to both the cesium and the T cations of neighboring tetrahedra. (C) 1997 Academic Press. C1 UNIV MARYLAND, COLLEGE PK, MD 20742 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 12 TC 18 Z9 18 U1 1 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD APR PY 1997 VL 130 IS 1 BP 97 EP 102 DI 10.1006/jssc.1997.7284 PG 6 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA XB116 UT WOS:A1997XB11600014 ER PT J AU Zelkowitz, M Cuthill, B AF Zelkowitz, M Cuthill, B TI Application of an information technology model to software engineering environments SO JOURNAL OF SYSTEMS AND SOFTWARE LA English DT Article AB The Information Technology Engineering and Measurement (ITEM) Model has been developed to describe the information processing activities of an enterprise, both the automated tasks performed by computer and the manual processes performed by the information technology staff of an organization. In this article, the ITEM model is applied to the description of software engineering environments as extensions to two previously developed reference models, the NIST/ECMA framework (i.e., ''toaster'') model and the Project Support Environment reference model. The ability to measure the degree of automation within a process, the ability to define the complexity of a process, and the ability to measure technology transition via a concept called technological drift are all metrics that can evolve from this model. (C) 1997 by Elsevier Science Inc. C1 UNIV MARYLAND,DEPT COMP SCI,COLLEGE PK,MD 20742. RP Zelkowitz, M (reprint author), NIST,COMP SYST LAB,NORTH,ROOM 517,GAITHERSBURG,MD 20899, USA. NR 18 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0164-1212 J9 J SYST SOFTWARE JI J. Syst. Softw. PD APR PY 1997 VL 37 IS 1 BP 27 EP 40 DI 10.1016/S0164-1212(96)00045-3 PG 14 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA WK573 UT WOS:A1997WK57300004 ER PT J AU Law, PL Lioy, PJ Zelenka, MP Huber, AH McCurdy, TR AF Law, PL Lioy, PJ Zelenka, MP Huber, AH McCurdy, TR TI Evaluation of a probabilistic exposure model applied to carbon monoxide (pNEM/CO) using Denver Personal Exposure Monitoring Data SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article AB The probabilistic National Ambient Air Quality Standards (NAAQS) Exposure Model applied to carbon monoxide (pNEM/CO) was developed by the U.S. Environmental Protection Agency (EPA) to estimate frequency distributions of population exposure to carbon monoxide (GO) and the resulting carboxyhemoglobin (COHb) levels. To evaluate pNEM/CO, the model was set up to simulate CO exposure data collected during a Denver Personal Exposure Monitoring Study (PEM) conducted during the winter of 1982-1983. This paper compares computer-simulated exposure distributions obtained by pNEM/CO with the observed cumulative relative frequency distributions of population exposure to CO from 779 people in the Denver PEM study. The subjects were disaggregated into two categories depending upon whether they Lived in a home with a gas stove or an electric stove. The observed and predicted population exposure frequency distributions were compared in terms of 1-hr daily maximum exposure (1DME) and 8-hr daily maximum moving average exposure (8DME) for people Living in homes with gas stove or an electric stove. For 1DME, the computer-simulated results from pNEM/CO agreed most closely within the range of 6-13 ppm, but overestimated occurrences at low exposure (<6 ppm) and underestimated occurrences at high exposure (>13 ppm). For 8DME, the predicted exposures agreed best with observed exposures in the range of CO concentration between 5.5 and 7 ppm, and over-predicted occurrences below 5.5 ppm and under-predicted occurrences above 7 ppm. C1 EOHSI,EXPOSURE MEASUREMENT & ASSESSMENT DIV,PISCATAWAY,NJ 08855. NOAA,AIR RESOURCES LAB,ATMOSPHER SCI MODELING DIV,RES TRIANGLE PK,NC. US EPA,RES TRIANGLE PK,NC 27711. RI Lioy, Paul/F-6148-2011 NR 17 TC 23 Z9 24 U1 0 U2 0 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD APR PY 1997 VL 47 IS 4 BP 491 EP 500 PG 10 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA WU264 UT WOS:A1997WU26400009 PM 28065154 ER PT J AU Luecke, WE Wiederhorn, SM AF Luecke, WE Wiederhorn, SM TI Interlaboratory verification of silicon nitride tensile creep properties SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID BEHAVIOR AB Five laboratories tested NIST-supplied, pin-loaded, 76-mm-long tensile creep specimens at 1400 degrees C under a 150 MPa load using flag-based, laser extensometry, The laboratories reported failure time and strain and supplied the individual creep curves, Only one of the laboratories produced failure times that were significantly less than the others, It is likely that their reduced failure times resulted from small load calibration and test temperature errors, After steps were taken to ameliorate these problems, three additional tests yielded failure times that agreed with those of the other four laboratories, Although the times to failure from the four laboratories that initially agreed were statistically indistinguishable, their creep curves exhibited subtle differences, These differences probably arose because the laboratories used different gage length definitions, When we recalculated the creep curves to the same gage length definition, the differences between the four laboratories whose times to failure agreed, vanished, Although a number of the specimens exhibited edge chips, creep cracks, and obvious chemical interactions with the flags, the presence of these defects did not reduce the time or strain to failure, Two additional creep tests in our laboratory, using specimens that were grossly misaligned, yielded failure times and strains that were commensurate with those from well-aligned specimens. RP Luecke, WE (reprint author), NATL INST STAND & TECHNOL,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899, USA. NR 15 TC 24 Z9 24 U1 0 U2 2 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD APR PY 1997 VL 80 IS 4 BP 831 EP 838 PG 8 WC Materials Science, Ceramics SC Materials Science GA WV760 UT WOS:A1997WV76000001 ER PT J AU Latella, BA OConnor, BH Padture, NP Lawn, BR AF Latella, BA OConnor, BH Padture, NP Lawn, BR TI Hertzian contact damage in porous alumina ceramics SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID POLYCRYSTALLINE CERAMICS; GRAIN-SIZE; MICROMECHANICS; PRESSURE; DUCTILE AB A study has been made of Hertzian contact damage in porous and dense liquid-phase-sintered aluminas. Indentation stress-strain curves show increasing nonlinearity as the materials become more porous, illustrating an increasing component of ''quasi-plasticity'' in the contact damage. Observations of the surface and subsurface damage patterns using a bonded-interface sectioning technique reveal a transition in the Hertzian damage process, from classical tension-driven cone cracks in the high-density material, to distributed shear- and compression-driven subsurface damage and deformation in the porous materials. Strength tests on specimens subjected to cyclic indentations reveal a substantially higher susceptibility to fatigue in the most porous structure. C1 NIST, MAT SCI & ENGN LAB, GAITHERSBURG, MD 20899 USA. RP CURTIN UNIV TECHNOL, DEPT APPL PHYS, PERTH, WA 6845, AUSTRALIA. RI Padture, Nitin/A-9746-2009 OI Padture, Nitin/0000-0001-6622-8559 NR 23 TC 51 Z9 51 U1 0 U2 4 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD APR PY 1997 VL 80 IS 4 BP 1027 EP 1031 PG 5 WC Materials Science, Ceramics SC Materials Science GA WV760 UT WOS:A1997WV76000030 ER PT J AU Swanson, KL Kushner, PJ Held, IM AF Swanson, KL Kushner, PJ Held, IM TI Dynamics of barotropic storm tracks SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID PARALLEL SHEAR FLOWS; ROSSBY-WAVE BREAKING; CONTOUR DYNAMICS; MEAN FLOW; VORTEX; FILAMENTATION; CIRCULATION; PROPAGATION; VORTICITY; SURGERY AB Longitudinal variations in the upper-tropospheric time-mean how strongly modulate the structure and amplitude of upper-tropospheric eddies. This barotropic modulation is studied using simple models of wave propagation through zonally varying basic states that consist of contours separating regions of uniform barotropic potential vorticity. Such basic states represent in a simple manner the potential vorticity distribution in the upper troposphere. Predictions of the effect of basic-state zonal variations on the amplitude and spatial structure of eddies and their associated particle displacements are made using conservation of wave action or, equivalently, the linearized ''pseudoenergy'' wave activity. The predictions are confirmed using WKB theory and linear numerical calculations. The interaction of finite-amplitude disturbances with the basic flow is also analyzed numerically using nonlinear contour-dynamical simulations. It is found that breaking nonlinear contour waves undergo irreversible amplitude attenuation, scale lengthening, and frequency lowering upon passing through a region of weak basic-state flow. C1 PRINCETON UNIV,PROGRAM ATMOSPHER & OCEAN SCI,PRINCETON,NJ 08544. PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,PRINCETON,NJ 08542. RI Kushner, Paul/H-6716-2016 OI Kushner, Paul/0000-0002-6404-4518 NR 30 TC 59 Z9 60 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR 1 PY 1997 VL 54 IS 7 BP 791 EP 810 DI 10.1175/1520-0469(1997)054<0791:DOBST>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WR417 UT WOS:A1997WR41700002 ER PT J AU Kane, DJ Rodriguez, G Taylor, AJ Clement, TS AF Kane, DJ Rodriguez, G Taylor, AJ Clement, TS TI Simultaneous measurement of two ultrashort laser pulses from a single spectrogram in a single shot SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID GENERALIZED PROJECTIONS; PHASE; RETRIEVAL; INTENSITY; AMPLITUDE AB Frequency-resolved optical gating (FROG) is a technique that produces a spectrogram of an ultrashort laser pulse. The intensity and phase of the ultrashort laser pulse can be determined through solving for the phase of the spectrogram with an iterative, phase-retrieval algorithm. This work presents a pew phase-retrieval algorithm that retrieves both the probe and the gate pulses independently by converting the FROG phase-retrieval problem to an eigenvector problem. The new algorithm is robust and general, It is tested theoretically by use of synthetic data sets and experimentally by use of single-shot, polarization-gate FROG. We independently and simultaneously characterize the electric field amplitude and phase of a pulse (probe) that was passed though 200 mm of BK7 glass and the amplitude of an unchanged pulse (gate) from an amplified Ti:sapphire laser. When the effect of the 200 mm of BK7 glass; was removed mathematically from the probe, there was good agreement between the measured gate and the calculated, prechirped probe. (C) 1997 Optical Society of America. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NATL INST STAND & TECHNOL,BOULDER,CO 80303. UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. RP Kane, DJ (reprint author), SW SCI INC,1570 PACHECO ST,SUITE E-11,SANTA FE,NM 87505, USA. RI Clement, Tracy/A-8885-2008; Rodriguez, George/G-7571-2012 OI Rodriguez, George/0000-0002-6044-9462 NR 21 TC 62 Z9 64 U1 1 U2 7 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD APR PY 1997 VL 14 IS 4 BP 935 EP 943 DI 10.1364/JOSAB.14.000935 PG 9 WC Optics SC Optics GA WU017 UT WOS:A1997WU01700031 ER PT J AU Heath, RB DeLong, R Jameson, V Bradley, D Spraker, T AF Heath, RB DeLong, R Jameson, V Bradley, D Spraker, T TI Isoflurane anesthesia in free ranging sea lion pups SO JOURNAL OF WILDLIFE DISEASES LA English DT Article DE Zalophus californianus; sea lions; pinniped; equine foals; anesthesia; isoflurane ID ZALOPHUS-CALIFORNIANUS; HALOTHANE AB California sea lion pups, Zalophus californianus, (n = 151), were captured and anesthetized for (mean +/- SD) 17.6 +/- 7.8 min on San Miguel Island, California (USA) in November of 1992. Mask isoflurane anesthesia allowed intubation in 7.1 +/- 2.74 min. Pups recovered and walked in 7.32 +/- 4.8 min. Mask anesthesia in pups resulted in relaxation in 45 +/- 14 sec. Safe, brief anesthesia was delivered in support of weighing, medical evaluation, and short surgical procedures. Recovery character of all pups was sufficient to permit release to the free ranging state immediately after surgery, saving labor, supervision personnel, and postoperative time. C1 COLORADO STATE UNIV,DEPT CLIN SCI,FT COLLINS,CO 80523. NATL MARINE MAMMAL LAB,SEATTLE,WA 98115. RP Heath, RB (reprint author), COLORADO STATE UNIV,DIAGNOST LAB,FT COLLINS,CO 80523, USA. NR 12 TC 46 Z9 51 U1 0 U2 2 PU WILDLIFE DISEASE ASSN, INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044-8897 SN 0090-3558 J9 J WILDLIFE DIS JI J. Wildl. Dis. PD APR PY 1997 VL 33 IS 2 BP 206 EP 210 PG 5 WC Veterinary Sciences SC Veterinary Sciences GA WW770 UT WOS:A1997WW77000004 PM 9131549 ER PT J AU Dziak, RP Fox, CG Matsumoto, H Schreiner, AE AF Dziak, RP Fox, CG Matsumoto, H Schreiner, AE TI The April 1992 Cape Mendocino earthquake sequence: Seismo-acoustic analysis utilizing fixed hydrophone arrays SO MARINE GEOPHYSICAL RESEARCHES LA English DT Article DE Cape Mendocino; earthquake; hydrophone; T-waves; acoustic propagation ID GORDA PLATE; TRIPLE JUNCTION; CALIFORNIA; SUBDUCTION; MOMENT; RIDGE AB The oceanic T-waves of earthquakes associated with the 1992 Cape Mendocino earthquake sequence were recorded and analyzed using fixed hydrophone arrays located throughout the northeast Pacific Ocean. The T-waves of these events were well recorded with high S/N ratios and strong acoustic energy present over a 0-64 Hz bandwidth. The smallest event recorded by the hydrophone arrays from the sequence had a local magnitude of 2.4. The hydrophone records of the three largest shocks in the sequence (M-L 6.9, 6.2, 6.5) exhibited both T-waves and lithospheric phases from these events. Low-pass filtering (2 Hz) of the lithospheric phases yielded a clear P-wave arrival for epicentral distances of <10 degrees, but no apparent S-wave. A seafloor cable-break was detected immediately after the second M > 6 aftershock, possibly the result of a submarine slide. The direct P-wave hydrophone records from the second large aftershock showed a relatively high-amplitude, high-frequency arrival, consistent with seismic analyses which used this information to infer rupture direction. The rupture direction was toward the location of the cable break, thus rupture directivity possibly played a role in initiating the slide event. Modelling of the T-wave propagation path, using the Parabolic Equation model, produced estimates of the acoustic transmission loss from epicenter to receiver. The transmission loss to the most distant phones is typically 10-20 dB, and can be as large as 50-70 dB for acoustic propagation paths that cross the continental margin. The amount of acoustic energy each earthquake released into the ocean at the seafloor-water interface was estimated applying the transmission loss and instrument response to the recorded T-wave signals. This acoustic source power level was calculated for 41 events with magnitudes over a recorded range of 2.4 less than or equal to M-L less than or equal to 6.9, with 17 of these events having their seismic moment estimates available through the NEIC. Ground displacement spectra were estimated from the acoustic power spectra and showed no indication of a corner frequency. Thus empirical analyses relating source level to magnitude and seismic moment were necessary to quantitatively derive an earthquake's size from hydrophone records. The results of indicator variable regression analyses suggest that T-wave source level increases linearly with the event's local magnitude and seismic moment. Furthermore, the source power level versus magnitude relationships for oceanic and continental earthquakes are significantly different, probably illustrating differences in the seismic and acoustic propagation paths from hypocenter to the hydrophone receivers. The results indicate that acoustic measurements provide a reasonable estimate of magnitude and seismic moment of an oceanic earthquake that was not detected by land-based seismic networks. C1 NOAA,HATFIELD MARINE SCI CTR,PACIFIC MARINE ENVIRONM LAB,NEWPORT,OR 97365. RP Dziak, RP (reprint author), OREGON STATE UNIV,HATFIELD MARINE SCI CTR,COOPERAT INST MARINE RESOURCES STUDIES,NEWPORT,OR 97365, USA. NR 36 TC 22 Z9 24 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0025-3235 J9 MAR GEOPHYS RES JI Mar. Geophys. Res. PD APR PY 1997 VL 19 IS 2 BP 137 EP 162 DI 10.1023/A:1004256910362 PG 26 WC Geochemistry & Geophysics; Oceanography SC Geochemistry & Geophysics; Oceanography GA XN354 UT WOS:A1997XN35400003 ER PT J AU Westlake, RL Perryman, WL Ono, KA AF Westlake, RL Perryman, WL Ono, KA TI Comparison of vertical aerial photographic and ground censuses of Steller sea lions at Ano Nuevo Island, July 1990-1993 SO MARINE MAMMAL SCIENCE LA English DT Article DE Steller sea lion; Eumetopias jubatus; pups; non-pups; Ano Nuevo Island; vertical aerial photo counts; ground counts; replicate surveys; trends in abundance ID DETECTING TRENDS; POWER AB Counts of Steller sea lion (Eumetopias jubatus) PUPS and non-pups (adults and juveniles) from aerial photographs of rookeries at Ano Nuevo Island between 1990 and 1993 were significantly higher than those made on the ground. Based on regression of natural logs of photographic counts versus year, the number of pups declined at a rate of -0.099/yr while non-pup numbers declined at -0.315/yr. Examination of ground count data for the same period revealed a significant decline in non-pups (-0.139/yr), but no trend was detected in the ground counts of pups. The regression coefficients from photographic and ground counts of non-pups did not differ significantly. Power analyses using the program TRENDS indicated that detectable rates of change in abundance from four annual surveys were much lower for counts of pups than counts of non-pups where sampling precision was based on fits to linear models. C1 UNIV NEW ENGLAND,DEPT LIFE SCI,BIDDEFORD,ME 04005. RP Westlake, RL (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,8604 LA JOLLA SHORES DR,LA JOLLA,CA 92038, USA. NR 25 TC 6 Z9 6 U1 0 U2 2 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD APR PY 1997 VL 13 IS 2 BP 207 EP 218 DI 10.1111/j.1748-7692.1997.tb00628.x PG 12 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA WU789 UT WOS:A1997WU78900004 ER PT J AU Wickens, P York, AE AF Wickens, P York, AE TI Comparative population dynamics of fur seals SO MARINE MAMMAL SCIENCE LA English DT Review DE fur seal; life history; population dynamics; modeling; Arctocephalus; Callorhinus ID ARCTOCEPHALUS-PUSILLUS-PUSILLUS; NEW-ZEALAND; SOUTH-GEORGIA; CALLORHINUS-URSINUS; AMSTERDAM-ISLAND; PUP PRODUCTION; GAZELLA; FORSTERI; TROPICALIS; MORTALITY AB The population sizes, trends, exploitation, and life history parameters for the ten fur seal species and subspecies are summarized. The largest population is that of Arctocephalus pusillus pusillus with approximately two million seals, and the smallest is A, townsendi with approximately 7,000 individuals. Most populations are legally protected, although controlled harvesting may occur. None of the fur seal populations is currently known to be decreasing. Data are presented for parameters related to the survival of pups, juveniles, adults, and territorial males, and to reproduction, including the age of attainment of territorial status, aggregation sizes, age of first parturition, pregnancy rates, sex ratios of young animals, and information on the birth seasons of the different species. Since pinnipeds are often of concern in fisheries management, their daily consumption rates are of importance, and consequently data on body masses are summarized and the paucity of data on consumption rates as a function of body mass noted. A simplified age-structured model is developed, and the results of this model are compared with results from more detailed models based on two published life tables for Callorhinus ursinus. This comparison shows that the use of the simplified age-structured model is justified to explore changes in population growth rate. However, the simplified model does show exaggerated age structure effects compared to the more detailed models. This model is used to compare the population dynamics of those species for which sufficient data are available. Areas in which limited, or no, data are available for the different fur seal species are highlighted. C1 NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,NATL MARINE MAMMAL LAB,SEATTLE,WA 98115. RP Wickens, P (reprint author), UNIV CAPE TOWN,MARINE BIOL RES INST,ZA-7700 RONDEBOSCH,CAPE TOWN,SOUTH AFRICA. NR 122 TC 77 Z9 77 U1 0 U2 26 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD APR PY 1997 VL 13 IS 2 BP 241 EP 292 DI 10.1111/j.1748-7692.1997.tb00631.x PG 52 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA WU789 UT WOS:A1997WU78900007 ER PT J AU LeDuc, RG Perrin, WF Debrot, AO Barros, NB vanBree, PJH AF LeDuc, RG Perrin, WF Debrot, AO Barros, NB vanBree, PJH TI Stenella attenuata from Curacao misidentified as S-coeruleoalba SO MARINE MAMMAL SCIENCE LA English DT Letter C1 CARMABI FDN,CURACAO,NETH ANTILLES. HUBBS SEA WORLD RES INST,ORLANDO,FL 32869. UNIV AMSTERDAM,ZOOL MUSEUM,NL-1092 AD AMSTERDAM,NETHERLANDS. RP LeDuc, RG (reprint author), SW FISHERIES SCI CTR,POB 271,LA JOLLA,CA 92038, USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD APR PY 1997 VL 13 IS 2 BP 356 EP 357 DI 10.1111/j.1748-7692.1997.tb00643.x PG 2 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA WU789 UT WOS:A1997WU78900019 ER PT J AU Sindermann, CJ AF Sindermann, CJ TI The search for cause and effect relationships in marine pollution studies SO MARINE POLLUTION BULLETIN LA English DT Editorial Material ID EPIDEMIOLOGY; INFERENCE RP NOAA, OXFORD, MD USA. NR 19 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD APR PY 1997 VL 34 IS 4 BP 218 EP 221 DI 10.1016/S0025-326X(97)00014-3 PG 4 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA XE088 UT WOS:A1997XE08800001 ER PT J AU Basson, M Fogarty, MJ AF Basson, M Fogarty, MJ TI Harvesting in discrete-time predator-prey systems SO MATHEMATICAL BIOSCIENCES LA English DT Article ID DELAYED-RECRUITMENT MODEL; MULTISPECIES FISHERIES; POPULATION-DYNAMICS; ECOLOGICAL MODELS; CHAOS; MANAGEMENT; BEHAVIOR AB Fisheries for assemblages of interacting species with seasonal recruitment occur throughout temperate and boreal regions of the world ocean. Such systems are conveniently modeled within a difference-equation framework. Here, we examine the dynamic behavior of discrete-time models for an exploited predator-prey system. We contrast the dynamic properties of an aggregate production model and an age-structured model in which recruitment and mortality are explicitly considered. The joint effects of harvesting and interspecific interactions on the stability of the system are defined and contrasted with results for single species systems. We demonstrate that harvesting is a potentially stabilizing factor in the production model and in an age-structured model in which juveniles are harvested and that the relative magnitude of the interaction between predator and prey strongly affects the exploitation levels at which stabilization occurs. In contrast, harvesting is potentially destabilizing (i.e., results in complex dynamics) in an age-structured model with harvesting of adults only; again, the magnitude of the interaction determines the stability boundaries, with stronger interactions leading to a broader range of stable parameter space. In both the aggregate production model and the age-structured model with harvesting of juvenile predator and prey, exploitation effectively reduces the intrinsic rate of increase of the populations; for prey, this effect is amplified by high predation mortality rates. Sustainable levels of exploitation for both predators and prey are lower for the case where juveniles are harvested. Predators and resource harvesters can be viewed as competitors for the prey, and sustainable harvest levels are directly affected by the magnitude of predation mortality. These considerations expand the scope of issues to be resolved in fishery management to include factors such as trade-offs between mean yield and the potential for intrinsic variability and the role of predator-prey interactions in shaping the dynamics of exploited systems. (C) Elsevier Science Inc., 1997. C1 NOAA, NATL MARINE FISHERIES SERV, NE FISHERIES SCI CTR, WOODS HOLE, MA 02543 USA. NR 51 TC 22 Z9 24 U1 1 U2 13 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0025-5564 J9 MATH BIOSCI JI Math. Biosci. PD APR 1 PY 1997 VL 141 IS 1 BP 41 EP 74 DI 10.1016/S0025-5564(96)00173-3 PG 34 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA WM790 UT WOS:A1997WM79000003 PM 9077079 ER PT J AU Stensrud, DJ Gall, RL Nordquist, MK AF Stensrud, DJ Gall, RL Nordquist, MK TI Surges over the Gulf of California during the Mexican Monsoon SO MONTHLY WEATHER REVIEW LA English DT Article ID 4-DIMENSIONAL DATA ASSIMILATION; PLANETARY BOUNDARY-LAYER; MARITIME TROPICAL AIR; AREA MESOSCALE MODEL; NUMERICAL-SIMULATION; WAVE DISTURBANCES; CENTRAL ARIZONA; EASTERLY WAVES; NORTH-AMERICA; PARAMETERIZATION AB Northward surges of relatively cool, moist, maritime air from the tropical Pacific into the southwestern United States occur via the Gulf of California every summer during the Mexican monsoon season. These surges advect large amounts of moisture northward and promote increased convective activity in Arizona. Mesoscale model output from 32 successive 24-h simulations are used to examine both the large-scale and mesoscale features associated with surge events. Model data are compared to high-resolution aircraft measurements on two days, showing clearly that the model is capable of reproducing many of the detailed structures found in the observations. Results from a large-scale analysis indicate that strong surges are produced in the model when a midlatitude trough is in the proper phase relationship with a tropical easterly wave. weak surges occur when this relationship is missing. C1 NATL CTR ATMOSPHER RES,MMM,BOULDER,CO 80307. NATL WEATHER SERV,EUREKA,CA. RP Stensrud, DJ (reprint author), NATL SEVERE STORMS LAB,ERL,NOAA,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. NR 55 TC 108 Z9 108 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD APR PY 1997 VL 125 IS 4 BP 417 EP 437 DI 10.1175/1520-0493(1997)125<0417:SOTGOC>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WP480 UT WOS:A1997WP48000001 ER PT J AU Takacs, E OnodiSzucs, Z Ratliff, LP Gillaspy, JD Palinkas, J AF Takacs, E OnodiSzucs, Z Ratliff, LP Gillaspy, JD Palinkas, J TI X-ray emission for 3-137 keV Ar17+ impacting SiO2 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT Proceedings of the 6th Workshop on Fast Ion-Atom Collision Processes CY SEP 09-13, 1996 CL DEBRECEN, HUNGARY ID HIGHLY CHARGED IONS; HOLLOW ATOMS; SURFACE; SLOW AB We report X-ray spectra from Ar17+ impacting a SiO2 surface at 30 degrees from normal incidence, for projectile energies ranging from 3 to 137 keV. At the highest energy we see only X-rays from the filling of the argon K shell. As the projectile energy is reduced, these argon X-rays are gradually reduced to zero while a silicon K-alpha peak appears. We interpret these data to be the result of the onset of a direct transfer of a silicon K-shell electron to the K-shell vacancy in the argon projectile. We suggest that this transfer occurs through an argon-silicon Auger process which takes place during a close collision in the solid. The velocity dependence of this process is not yet fully understood. C1 NATL INST STAND & TECHNOL,ATOM PHYS DIV,GAITHERSBURG,MD 20899. RP Takacs, E (reprint author), LAJOS KOSSUTH UNIV,EXPT PHYS DEPT,BEM TER 18-A,DEBRECEN,HUNGARY. RI Palinkas, Jozsef/B-2993-2011 NR 27 TC 6 Z9 6 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD APR PY 1997 VL 124 IS 2-3 BP 431 EP 434 DI 10.1016/S0168-583X(96)01054-3 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA WU535 UT WOS:A1997WU53500047 ER PT J AU Irlandi, EA Crawford, MK AF Irlandi, EA Crawford, MK TI Habitat linkages: The effect of intertidal saltmarshes and adjacent subtidal habitats on abundance, movement, and growth of an estuarine fish SO OECOLOGIA LA English DT Article DE habitat heterogeneity; Lagodon rhomboides; landscape ecology; saltmarsh Seagrass ID JUVENILE BLUE CRABS; CALLINECTES-SAPIDUS; FUNDULUS-HETEROCLITUS; ZOSTERA-MARINA; SALT MARSHES; COMMUNITIES; PREDATION; EELGRASS; HETEROGENEITY; MEADOWS AB In this study we used pinfish (Lagodon rhomboides) in field experiments to examine linkages between intertidal saltmarsh and adjacent subtidal habitats. Pinfish are more than twice as abundant in intertidal marshes adjacent to seagrass beds than in those adjacent to the unvegetated subtidal bottom. Movement of pinfish between the marsh edge and the adjacent subtidal habitat was greater for fish captured in areas with both intertidal and subtidal vegetation than in those with intertidal vegetation and adjacent unvegetated mudflats. This movement provides an important link between habitats, allowing transfer of marsh-derived secondary production to subtidal seagrass beds and vice versa. Pinfish held in enclosures with both intertidal and subtidal vegetation were, on average, approximately 90% heavier than fish held in enclosures with intertidal vegetation and unvegetated subtidal bottom. Because saltmarshes and seagrass beds contribute to the production of living marine resources, active measures are being taken to preserve and restore these habitats. The results from this study have direct application to decisions concerning site selection and optimal spatial proximity of saltmarsh and seagrass habitats in the planning of restoration and mitigation projects. To maximize secondary production and utilization of intertidal marshes, managers may opt to restore and/or preserve marshes adjacent to subtidal seagrass beds. C1 NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES CTR,BEAUFORT LAB,BEAUFORT,NC 28516. NR 35 TC 112 Z9 114 U1 1 U2 33 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0029-8549 J9 OECOLOGIA JI Oecologia PD APR PY 1997 VL 110 IS 2 BP 222 EP 230 DI 10.1007/s004420050154 PG 9 WC Ecology SC Environmental Sciences & Ecology GA WW157 UT WOS:A1997WW15700011 PM 28307429 ER PT J AU Manabe, S Stouffer, RJ AF Manabe, S Stouffer, RJ TI Coupled ocean-atmosphere model response to freshwater input: Comparison to Younger Dryas event SO PALEOCEANOGRAPHY LA English DT Article ID ATLANTIC THERMOHALINE CIRCULATION; ABRUPT CLIMATE-CHANGE; TRANSIENT RESPONSES; LAST DEGLACIATION; DEEP CIRCULATION; GRADUAL CHANGES; NEW-ZEALAND; CO2; TEMPERATURE; INCREASE AB This study explores the responses of a coupled ocean-atmosphere model to the discharge of freshwater into the North Atlantic Ocean. In the first numerical experiment in which freshwater is discharged into high North Atlantic latitudes over a period of 500 years, the thermohaline circulation (THC) in the Atlantic Ocean weakens, reducing surface air temperature over the northern North Atlantic Ocean and Greenland and, to a lesser degree, over the Arctic Ocean, the Scandinavian peninsula, and the Circumpolar Ocean and the Antarctic continent of the southern hemisphere. Upon the termination of the water discharge at the 500th year, the THC begins to intensify, regaining its original intensity in a few hundred years. With the exception of the Pacific sector of the Circumpolar Ocean of the southern hemisphere, where the surface air temperature recovery is delayed, the climate of the northern North Atlantic and surrounding regions rapidly resumes its original distribution. The evolution of the ocean-atmosphere system described above resembles the Younger Dryas event as inferred from the comprehensive analysis of ice cores and deep-sea and lake sediments. In the second experiment, in which the same amount of freshwater is discharged into the subtropical North Atlantic again over a period of 500 years, the THC and climate evolve in a manner qualitatively similar to the first experiment. However, the magnitude of the THC response is 4-5 times smaller. It appears that freshwater is much less effective in weakening the THC if it were discharged outside high North Atlantic latitudes. RP Manabe, S (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,POB 308,PRINCETON,NJ 08542, USA. NR 58 TC 231 Z9 240 U1 1 U2 26 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0883-8305 J9 PALEOCEANOGRAPHY JI Paleoceanography PD APR PY 1997 VL 12 IS 2 BP 321 EP 336 DI 10.1029/96PA03932 PG 16 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA WQ646 UT WOS:A1997WQ64600012 ER PT J AU Kildiyarova, RR Joshi, YN Churilov, SS Ryabtsev, AN Sugar, J AF Kildiyarova, RR Joshi, YN Churilov, SS Ryabtsev, AN Sugar, J TI A study of the 5d(2), 5d6p and 5d5f configurations of Pt IX SO PHYSICA SCRIPTA LA English DT Article AB The spectrum of eight-times ionized platinum was photographed in the 100-400 Angstrom region using a 2-m and a IO-m grazing incidence spectrographs. The 5d(2)-(5d6p + 5d5f) transitions of Pt IX were analysed and 116 lines have been classified in the 216-345 Angstrom region. All nine levels of the 5d(2) configuration, all twelve levels of the 5d6p configuration and eighteen of twenty levels of the 5d5f configuration have been established. Hartree-Fock and least-squares fitted parametric calculations were carried out and they interpret the observed level structure quite satisfactorily. C1 ST FRANCIS XAVIER UNIV,DEPT PHYS,ANTIGONISH,NS B2G 2W5,CANADA. NIST,GAITHERSBURG,MD 20899. RP Kildiyarova, RR (reprint author), RUSSIAN ACAD SCI,INST SPECT,TROITSK 142092,MOSCOW REGION,RUSSIA. NR 8 TC 9 Z9 9 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PD APR PY 1997 VL 55 IS 4 BP 438 EP 444 DI 10.1088/0031-8949/55/4/011 PG 7 WC Physics, Multidisciplinary SC Physics GA WU429 UT WOS:A1997WU42900011 ER PT J AU Burke, JP Bohn, JL Esry, BD Greene, CH AF Burke, JP Bohn, JL Esry, BD Greene, CH TI Impact of the Rb-87 singlet scattering length on suppressing inelastic collisions SO PHYSICAL REVIEW A LA English DT Article ID ALKALI AB A computation of Rb-87-Rb-87 spin-exchange rate constants as functions of the two-body singlet scattering length a(s) demonstrates that the inelastic collision rate is suppressed over a small range of the possible values for a(s). A two-channel model relates this inelastic suppression to an interference phenomenon, manifested in the near coincidence of the singlet and triplet scattering lengths. This mechanism explains the diminished rates measured in recent ''double-trap'' experiments. Combining information extracted from these rates and from previous scattering length measurements allows us to place bounds on the Rb-87 Singlet scattering length (74-102 a.u.). C1 UNIV COLORADO, DEPT PHYS, BOULDER, CO 80309 USA. NATL INST STAND & TECHNOL, QUANTUM PHYS LAB, BOULDER, CO 80309 USA. RP UNIV COLORADO, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. RI Greene, Chris/C-3821-2011; Esry, Brett/H-7511-2013 OI Greene, Chris/0000-0002-2096-6385; Esry, Brett/0000-0003-3207-8526 NR 24 TC 61 Z9 61 U1 0 U2 3 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 APR PY 1997 VL 55 IS 4 BP R2511 EP R2514 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WT252 UT WOS:A1997WT25200007 ER PT J AU Monroe, C Leibfried, D King, BE Meekhof, DM Itano, WM Wineland, DJ AF Monroe, C Leibfried, D King, BE Meekhof, DM Itano, WM Wineland, DJ TI Simplified quantum logic with trapped ions SO PHYSICAL REVIEW A LA English DT Article ID COMPUTATION; GATES; DECOHERENCE; TRANSITION; UNIVERSAL; DYNAMICS AB We describe a simplified scheme for quantum logic with a collection of laser-cooled trapped atomic ions. Building on the scheme of Cirac and Zoller, we show how the fundamental controlled-NOT gate between a collective mode of ion motion and the internal slates of a single ion can be reduced to a single laser pulse, and the need for a third auxiliary internal electronic state can be eliminated. RP Monroe, C (reprint author), NATL INST STAND & TECHNOL, 325 BROADWAY, BOULDER, CO 80303 USA. RI Monroe, Christopher/G-8105-2011 NR 26 TC 108 Z9 108 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 1997 VL 55 IS 4 BP R2489 EP R2491 PG 3 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WT252 UT WOS:A1997WT25200001 ER PT J AU Hu, X AF Hu, X TI Magnetization reversal and coercive force in ultrathin films with perpendicular surface anisotropy: Micromagnetic theory SO PHYSICAL REVIEW B LA English DT Article ID FERROMAGNETIC-FILMS; SPIN ANISOTROPY; THIN-FILMS; MAGNETORESISTANCE; SUPERLATTICES AB Quasistatic magnetization reversal in ultrathin magnetic films with perpendicular surface anisotropy is discussed. In order to focus on the role of the surface anisotropy, magnetization is presumed uniform across the film plane, and its variation along the film normal is subject to micromagnetic analysis of a functional including the shape anisotropy energy from dipolar interactions. Different reversal processes-such as nucleations, coherent and incoherent rotations, domain-wall motion, and abrupt jumps-are found in films, depending on the values of shape anisotropy, surface anisotropy, exchange stiffness, and film thickness. The coercivity of ultrathin magnetic films in fields perpendicular to the film plane decreases with the square of the reciprocal of the Nm thickness. which coincides very well with experimental observations. Magnetization reversal processes resulting from applying in-plane external fields are also described. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. NR 27 TC 17 Z9 17 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 1 PY 1997 VL 55 IS 13 BP 8382 EP 8389 DI 10.1103/PhysRevB.55.8382 PG 8 WC Physics, Condensed Matter SC Physics GA WV252 UT WOS:A1997WV25200056 ER PT J AU Chopra, HD Hockey, BJ Chen, PJ Egelhoff, WF Wuttig, M Hua, SZ AF Chopra, HD Hockey, BJ Chen, PJ Egelhoff, WF Wuttig, M Hua, SZ TI Nanostructural considerations in giant magnetoresistive Co-Cu-based symmetric spin valves SO PHYSICAL REVIEW B LA English DT Article ID ANTIFERROMAGNETIC INTERLAYER EXCHANGE; LAYERED MAGNETIC-STRUCTURES; CO/CU MULTILAYERS; ENHANCED MAGNETORESISTANCE; SUPERLATTICES; SANDWICHES AB The effect of surface modifying species, Pb, on the nanostructure and resulting giant magnetoresistive properties of symmetric spin valves of the type NiO/Co/Cu/Co/Cu/Co/NiO is investigated, using high-resolution and conventional transmission electron microscopy. When a monolayer of Pb is deposited on the first Co/Cu bilayer, the net ferromagnetic coupling between the middle Co layer and the NiO-pinned Co layers is reduced by an order of magnitude. Nanostructure investigations revealed that, in the absence of Pb, the Co and Cu layers grow coherently over each other within columnar grains. The coherent growth mode of the metal layers in the Pb-free samples gives rise to topographically correlated ferromagnetic films, a requisite if ferromagnetic coupling arises from Neel's ''orange-peel'' effect. In the presence of Pb, the deposition proceeds by the nucleation of fine, (apparently) randomly oriented nanocrystallites in successive metal layers, instead of a coherent growth mode, thereby disrupting topographic correlation between the adjacent ferromagnetic films, and reducing the net ferromagnetic coupling due to Neel's ''orange-peel'' effect. Due to well defined orientation relationships between the adjacent grains in the Pb-free samples, a faceted surface morphology develops, on which the top NiO film is deposited. This is in contrast to the Ph-containing samples which have an irregular, undulatorylike surface. Although not directly observable, the characteristics of Co-Cu interfaces can be inferred from the nature of the top Co surface. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. UNIV MARYLAND,DEPT MAT & NUCL ENGN,COLLEGE PK,MD 20742. MAT INNOVAT INC,W LEBANON,NH 03784. NR 36 TC 44 Z9 44 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 1 PY 1997 VL 55 IS 13 BP 8390 EP 8397 DI 10.1103/PhysRevB.55.8390 PG 8 WC Physics, Condensed Matter SC Physics GA WV252 UT WOS:A1997WV25200057 ER PT J AU Gallagher, T Gilliland, GL AF Gallagher, T Gilliland, GL TI Water in crystal contacts: Retention of bridging waters SO PROTEIN AND PEPTIDE LETTERS LA English DT Article ID SUBTILISIN AB In 3 well-refined crystal structures of subtilisin BPN' ih different space groups, crystal contact hydration was compared. The structures are: 1sup, space group C2, resolution 1.6 Angstrom, with 194 waters; 2st1, P2(1)2(1)2(1), resolution 1.8 Angstrom, with 154 waters, and 1sub, P2(1), resolution 1.75 Angstrom, with 200 waters. Of 106 bridging water sites, approximately 50% retain the water in the absence of the crystal contact, suggesting that bound water may serve as a template for crystal contact formation. Bridging waters that are retained on both surfaces must overlap when the contact forms, eliminating one water in a condensation reaction. In such cases, the water sites are geometric determinants of the contact. Specific examples are described in the C2 crystal structure. C1 UNIV MARYLAND, MARYLAND BIOTECHNOL INST, CTR ADV RES BIOTECHNOL, ROCKVILLE, MD 20850 USA. NIST, ROCKVILLE, MD 20850 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU BENTHAM SCIENCE PUBL LTD PI SHARJAH PA EXECUTIVE STE Y26, PO BOX 7917, SAIF ZONE, 1200 BR SHARJAH, U ARAB EMIRATES SN 0929-8665 J9 PROTEIN PEPTIDE LETT JI Protein Pept. Lett. PD APR PY 1997 VL 4 IS 2 BP 81 EP 86 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA WX941 UT WOS:A1997WX94100002 ER PT J AU Pu, ZX Kalnay, E Derber, JC Sela, JG AF Pu, ZX Kalnay, E Derber, JC Sela, JG TI Using forecast sensitivity patterns to improve future forecast skill SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE adjoint model; data assimilation; numerical weather prediction; forecast errors; sensitivity; 4-D VAR ID VARIATIONAL DATA ASSIMILATION; ANALYSIS SYSTEM AB A simple, relatively inexpensive technique has been developed for using past forecast errors to improve the future forecast skill. The method uses the forecast model and its adjoint and can be considered as a simplified 4-dimensional variational (4-D VAR) system. One- or two-day forecast errors are used to calculate a small perturbation (sensitivity perturbation) to the analyses that minimizes the forecast error. The longer forecasts started from the corrected initial conditions, although better than the original forecasts, are still significantly worse than the shorter forecasts started from the latest analysis, even though they both had access to information covering the same period. As a much less expensive alternative to 4-D VAR, the adjusted initial conditions from one or two days ago are used as a starting point for a second iteration of the regular NCEP analysis and forecast cycle until the present time (t = 0) analysis is reached. Forecast experiments indicate that the new analyses result in improvements to medium-range forecast skill, and suggest that the technique can be used in operations, since it increases the cost of the regular analysis cycle by a maximum factor of about 4 to 8, depending on the length of the analysis cycle that is repeated. Several possible operational configurations are also tested. The model used in these experiments is the NCEP's operational global spectral model with 62 waves triangular truncation and 28 sigma-vertical levels. An adiabatic version of the adjoint was modified to make it more consistent with the complete forecast model, including only a few simple physical parametrizations (horizontal diffusion and vertical mixing). This adjoint model was used to compute the gradient of the forecast error with respect to initial conditions. RP Pu, ZX (reprint author), NATL CTR ENVIRONM PREDICT,W-NCEP2,ROOM 207,5200 AUTH RD,CAMP SPRINGS,MD 20746, USA. RI Kalnay, Eugenia/F-4393-2010; OI Kalnay, Eugenia/0000-0002-9984-9906 NR 34 TC 15 Z9 16 U1 0 U2 0 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD APR PY 1997 VL 123 IS 540 BP 1035 EP 1053 PN B PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XB534 UT WOS:A1997XB53400011 ER PT J AU Camus, T AF Camus, T TI Real-time quantized optical flow SO REAL-TIME IMAGING LA English DT Article ID COMPUTATION; PERCEPTION; ALGORITHM; MOTION AB Algorithms based on the correlation of image patches can be robust in practice but are computationally intensive due to the computational complexity of their search-based nature. Performing the search over time instead of over space is linear in nature, rather than quadratic, and results in a very efficient algorithm. This, combined with implementations which are highly efficient on standard computing hardware, yields performance of 9 frames/sec on a scientific workstation. Although the resulting velocities are quantized with resulting quantization error, they have been shown to be sufficiently accurate for many robotic vision tasks such as time-to-collision and robotic navigation. Thus, this algorithm is highly suitable for real-time robotic vision research. (C) 1997 Academic Press Limited. RP NATL INST STAND & TECHNOL, INTELLIGENT SYST DIV, BLDG 220, RM B-124, GAITHERSBURG, MD 20899 USA. NR 40 TC 30 Z9 30 U1 5 U2 8 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1077-2014 J9 REAL-TIME IMAGING JI Real-Time Imaging PD APR PY 1997 VL 3 IS 2 BP 71 EP 86 DI 10.1006/rtim.1996.0048 PG 16 WC Computer Science, Artificial Intelligence; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA WX491 UT WOS:A1997WX49100002 ER PT J AU Brown, CW Podesta, GP AF Brown, CW Podesta, GP TI Remote sensing of coccolithophore blooms in the western South Atlantic Ocean SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID BIOGENIC SULFUR; NORTH-ATLANTIC; SHELF-BREAK; SATELLITE; MAINE; COLOR; GULF; DIMETHYLSULFIDE; PHYTOPLANKTON; CURRENTS AB High-reflectance patches are regularly observed off the southeastern coast of South America during the lat austral spring and summer in visible satellite imagery of the Coastal Zone Color Scanner (CZCS). Unfortunately, coincident in situ samples for identifying their cause are lacking. To ascertain the likelihood that these patches represent surface blooms of the coccolithophore Emiliania huxleyi, their distribution pattern was mapped and their spectral signature evaluated by classifying CZCS imagery with a supervised, multispectral classification scheme that had been developed to detect this phytoplankton species. On the basis of the similarity of these characteristics to those of documented cases, we conclude that the high-reflectance patches observed in surface waters of the shelf and beyond are E. huxleyi blooms. The blooms seasonally occupied an area as large as 550,000 km(2). Standing stock estimates indicate that the detected blooms produce an average of 1.5-4.9X10(5) metric tons of calcite carbon and 4.0X10(3) t of dimethyl sulfide sulfur. The bloom's production of these climatically relevant compounds and their alteration of optical properties in the surface layer suggest that the blooms significantly affect the biogeochemistry and ecology of this region. (C) Elsevier Science Inc., 1997. C1 UNIV MIAMI, ROSENSTIEL SCH MARINE & ATMOSPHER SCI, MIAMI, FL 33149 USA. RP Brown, CW (reprint author), NOAA, NATL ENVIRONM SATELLITE DATA & INFORMAT SERV, SATELLITE RES LAB, E-RA13, WASHINGTON, DC 20233 USA. RI Brown, Christopher/B-8213-2008; OI Brown, Christopher/0000-0002-9905-6391; Podesta, Guillermo/0000-0002-4909-0567 NR 44 TC 53 Z9 54 U1 1 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR PY 1997 VL 60 IS 1 BP 83 EP 91 DI 10.1016/S0034-4257(96)00140-X PG 9 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA WT709 UT WOS:A1997WT70900007 ER PT J AU Howard, LP Stone, JA AF Howard, LP Stone, JA TI Differential wavelength meter for laser tuning SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID INTERFEROMETER AB A simple interferometer for matching the wavelengths of tunable lasers is described. Our interferometer uses the angular dispersion of a diffraction grating at the Littrow angle to produce a tilted wavefront with respect to a reference mirror in an opposing arm of a Michelson interferometer. As a first step, the resulting interference pattern is adjusted to produce a null frill using a reference laser as a wavelength standard. When a tunable laser, such as a laser diode, is used to illuminate the system, the laser is simply tuned to reproduce the null fringe pattern established using the reference laser. When so tuned, the wavelength of the tunable laser is matched to that of the reference laser within about 3 GHz, close enough for optical heterodyning. RP Howard, LP (reprint author), NIST,DIV PRECIS ENGN,BLDG 220 ROOM A117,GAITHERSBURG,MD 20899, USA. NR 7 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 1997 VL 68 IS 4 BP 1648 EP 1651 DI 10.1063/1.1147971 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA WV617 UT WOS:A1997WV61700002 ER PT J AU Russell, TP Piermarini, GJ AF Russell, TP Piermarini, GJ TI A high pressure optical cell utilizing single crystal cubic zirconia anvil windows SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID DIAMOND CELL; KBAR AB A high pressure optical cell capable of producing pressures up to 13.2 GPa using gem-cut single crystal cubic zirconia (CZ) anvils was developed. Maximum pressures obtainable were found to depend upon the particular pressure transmitting medium and gasket material employed. The cubic zirconia anvil high pressure cell (CZAC) provides advantages over the diamond anvil cell in optical and infrared spectroscopy while still maintaining a substantial pressure capability. To demonstrate these advantages, microRaman, optical fluorescence, and infrared absorption measurements were made on diamond, ruby, and 1,3,5-trinitrohexahydro-1,3,5-triazine samples, respectively, using the CZAC cell under high pressure conditions. C1 NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899. RP Russell, TP (reprint author), USN,RES LAB,DIV CHEM,CODE 6110,WASHINGTON,DC 20375, USA. NR 17 TC 13 Z9 13 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 1997 VL 68 IS 4 BP 1835 EP 1840 DI 10.1063/1.1147955 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA WV617 UT WOS:A1997WV61700038 ER PT J AU Libes, D AF Libes, D TI Tcl/Tk-based agents for mail and news notification SO SOFTWARE-PRACTICE & EXPERIENCE LA English DT Article DE agents; biff; mail notification; Tcl; Tk; Usenet news notification AB Two agent implementations are described-one for mail notification and one for news notification, Both agents are implemented using Tcl, This paper provides a brief history and perspective of similar agents, Included are experiences using Tcl as an agent-implementation language, and comparisons of the results to similar agents, Also described are some new techniques of interest to Tcl programmers. (C) 1997 by John Wiley & Sons, Ltd. RP Libes, D (reprint author), NATL INST STAND & TECHNOL,BLDG 220,RM A-127,GAITHERSBURG,MD 20899, USA. NR 17 TC 2 Z9 2 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0038-0644 J9 SOFTWARE PRACT EXPER JI Softw.-Pract. Exp. PD APR PY 1997 VL 27 IS 4 BP 481 EP 493 DI 10.1002/(SICI)1097-024X(199704)27:4<481::AID-SPE94>3.0.CO;2-J PG 13 WC Computer Science, Software Engineering SC Computer Science GA WU487 UT WOS:A1997WU48700005 ER PT J AU Hsieh, G Mason, TO Garboczi, EJ Pederson, LR AF Hsieh, G Mason, TO Garboczi, EJ Pederson, LR TI Experimental limitations in impedance spectroscopy .3. Effect of reference electrode geometry/position SO SOLID STATE IONICS LA English DT Article DE impedance spectroscopy; YSZ; Pt electrode; Ag electrode; reference electrode ID STABILIZED ZIRCONIA INTERFACE; OXIDE FUEL-CELLS; CEMENT PASTE; OXYGEN REDUCTION; DISK ELECTRODE; RESISTANCE; LOCATION; MODEL AB Experiments and computer simulations on Pt/YSZ specimens in various electrode configurations were performed to investigate the effect of reference electrode geometry/position on the accuracy of impedance measurements. The internal, Luggin probe-type, geometry is the preferred reference electrode configuration as it accurately measures both electrolyte and electrode impedances. External, 'pseudoreference', electrodes sample an averaged effective potential and can register inaccurate electrolyte resistances, sometimes with distorted electrode arcs. A symmetric configuration can accurately measure the impedance of an electrode; however, the electrolyte resistance will not scale linearly according to sample dimensions, as one might expect, An asymmetric configuration exhibits both non-linear partitioning of electrolyte resistance and distortions in the electrode impedance are under certain circumstances. The reliability of three-electrode measurements is very sensitive to aspect ratio and electrode configuration. C1 NORTHWESTERN UNIV, DEPT MAT SCI & ENGN, EVANSTON, IL 60208 USA. NIST, BLDG MAT DIV, GAITHERSBURG, MD 20899 USA. PACIFIC NW LAB, DEPT CHEM & MAT SCI, RICHLAND, WA 99352 USA. RI Mason, Thomas/B-7528-2009 NR 29 TC 56 Z9 56 U1 3 U2 25 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD APR PY 1997 VL 96 IS 3-4 BP 153 EP 172 DI 10.1016/S0167-2738(97)00073-8 PG 20 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA WY909 UT WOS:A1997WY90900004 ER PT J AU Onsager, TG Lockwood, M AF Onsager, TG Lockwood, M TI High-latitude particle precipitation and its relationship to magnetospheric source regions SO SPACE SCIENCE REVIEWS LA English DT Review DE magnetosphere; ionosphere; low latitude boundary layer; cusp; mantle; polar rain; plasma sheet; plasma sheet boundary layer; particle Precipitation ID INTERPLANETARY MAGNETIC-FIELD; SHEET BOUNDARY-LAYER; GEOMAGNETICALLY ACTIVE TIMES; RECONNECTION RATE VARIATIONS; NIGHTSIDE AURORAL OVAL; LOW-ALTITUDE SATELLITE; PLASMA SHEET; ION PRECIPITATION; DAYSIDE IONOSPHERE; MAGNETOTAIL CONVECTION AB Two central issues in magnetospheric research are understanding the mapping of the low-altitude ionosphere to the distant regions of the magnetsphere, and understanding the relationship between the small-scale features detected in the various regions of the ionosphere and the global properties of the magnetosphere. The high-latitude ionosphere, through its magnetic connection to the outer magnetosphere, provides an important view of magnetospheric boundaries and the physical processes occurring there. All physical manifestations of this magnetic connectivity (waves, particle precipitation, etc.), however, have non-zero propagation times during which they are convected by the large-scale magnetospheric electric field, with phenomena undergoing different convection distances depending on their propagation times. Identification of the ionospheric signatures of magnetospheric regions and phenomena, therefore, can be difficult. Considerable progress has recently been made in identifying these convection signatures in data from low-and high-altitude satellites. This work has allowed us to learn much about issues such as: the rates of magnetic reconnection, both at the dayside magnetopause and in the magnetotail; particle transport across the open magnetopause; and particle acceleration at the magnetopause and the magnetotail current sheets. C1 RUTHERFORD APPLETON LAB, DIDCOT OX11 0QX, OXON, ENGLAND. RP NOAA, SPACE ENVIRONM CTR, 325 BROADWAY, BOULDER, CO 80303 USA. RI Lockwood, Mike/G-1030-2011 OI Lockwood, Mike/0000-0002-7397-2172 NR 115 TC 24 Z9 24 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD APR PY 1997 VL 80 IS 1-2 BP 77 EP 107 DI 10.1023/A:1004925720793 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XW668 UT WOS:A1997XW66800005 ER PT J AU Ho, DT Bliven, LF Wanninkhof, R Schlosser, P AF Ho, DT Bliven, LF Wanninkhof, R Schlosser, P TI The effect of rain on air-water gas exchange SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID WIND-SPEED; SULFUR-HEXAFLUORIDE; TRANSFER VELOCITIES; HUDSON ESTUARY; LAKES; PARAMETERS; INTERFACE; SF6 AB The relationship between gas transfer velocity and rain rate was investigated at NASA's Rain-Sea Interaction Facility (RSIF) using several SF6 evasion experiments. During each experiment, a water tank below the rain simulator was supersaturated with SF6, a synthetic gas, and the gas transfer velocities were calculated from the measured decrease in SF6 concentration with time. The results from experiments with 18 different rain rates (7 to 110 mm h(-1)) and 1 of 2 dropsizes (2.8 or 4.2 mm diameter) confirm a significant and systematic enhancement of air-water gas exchange by rainfall. The gas transfer velocities derived from our experiment were related to the kinetic energy flux calculated from the rain rate and dropsize. The relationship obtained for mono-dropsize rain at the RSIF was extrapolated to natural rain using the kinetic energy flux of natural rain calculated from the Marshall-Palmer raindrop size distribution. Results of laboratory experiments at RSIF were compared to field observations made during a tropical rainstorm in Miami, Florida and show good agreement between laboratory and field data. C1 COLUMBIA UNIV, DEPT EARTH & ENVIRONM SCI, PALISADES, NY 10964 USA. NASA, GODDARD SPACE FLIGHT CTR, LAB HYDROSPHER PROC, WALLOPS ISL, VA 23337 USA. NOAA, ATLANTIC OCEANOG & METEOROL LAB, OCEAN CHEM DIV, MIAMI, FL 33149 USA. RP Ho, DT (reprint author), COLUMBIA UNIV, LAMONT DOHERTY EARTH OBSERV, PALISADES, NY 10964 USA. RI Ho, David/A-3154-2011; Schlosser, Peter/C-6416-2012; bliven, francis/E-1450-2012 OI Ho, David/0000-0002-0944-6952; Schlosser, Peter/0000-0002-6514-4203; NR 29 TC 62 Z9 65 U1 0 U2 14 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 1997 VL 49 IS 2 BP 149 EP 158 DI 10.1034/j.1600-0889.49.issue2.3.x PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WZ858 UT WOS:A1997WZ85800003 ER PT J AU Coursey, BM AF Coursey, BM TI Standards for radioiodines SO THYROID LA English DT Article; Proceedings Paper CT International Symposium on Radioiodine CY AUG 24-27, 1996 CL MAYO CLINIC, PHILIPS HALL, ROCHESTER, MN HO MAYO CLINIC, PHILIPS HALL AB The National Institute of Standards and Technology, NIST (formerly National Bureau of Standards), is the nation's standards laboratory for civilian technology. NIST develops and maintains the nation's physical measurement standards for medical therapy and diagnostics. For the past 50 years, NIST has developed radioactivity Standard Reference Materials (SRMs) for radioiodines as well as decay-scheme data and test methods for use by the radiopharmaceutical manufacturers in their quality assurance and quality control at the point of manufacture. Methods of standardizing radioiodines include 4 pi beta-gamma coincidence counting (I-131), 4 pi beta-gamma anti-coincidence counting (I-129), 4 pi(e,x)-gamma coincidence counting (I-123), and gamma sum peak coincidence counting (I-125). NIST also uses sources standardized by these techniques to calibrate re-entrant ionization chambers (dose calibrators) and scintillation counters. SRMs of I-131 and I-125 are now available on an annual basis, and the long-lived I-129 has recently been reissued. RP Coursey, BM (reprint author), NIST,IONIZING RADIAT DIV,PHYS LAB,GAITHERSBURG,MD 20899, USA. NR 11 TC 1 Z9 1 U1 0 U2 1 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 SN 1050-7256 J9 THYROID JI Thyroid PD APR PY 1997 VL 7 IS 2 BP 285 EP 288 DI 10.1089/thy.1997.7.285 PG 4 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA WW437 UT WOS:A1997WW43700025 PM 9133702 ER PT J AU Johns, PM Maxwell, MR AF Johns, PM Maxwell, MR TI Sexual cannibalism: Who benefits? SO TRENDS IN ECOLOGY & EVOLUTION LA English DT Editorial Material ID PRAYING-MANTIS; SPIDER C1 NATL MARINE FISHERIES SERV,WOODS HOLE,MA 02543. RP Johns, PM (reprint author), UNIV CHICAGO,DEPT ECOL & EVOLUT,1101 E 57TH ST,CHICAGO,IL 60637, USA. NR 13 TC 28 Z9 30 U1 6 U2 35 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0169-5347 J9 TRENDS ECOL EVOL JI Trends Ecol. Evol. PD APR PY 1997 VL 12 IS 4 BP 127 EP 128 DI 10.1016/S0169-5347(97)01005-7 PG 2 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA WN303 UT WOS:A1997WN30300001 PM 21238005 ER PT J AU Leonartz, K Sahm, PR Coriell, SR AF Leonartz, K Sahm, PR Coriell, SR TI Convection in melts under varying gravity level between 0.001 g and 1 g SO ZEITSCHRIFT FUR METALLKUNDE LA German DT Article ID SOLUTAL CONVECTION; BINARY ALLOY; SOLIDIFICATION; STABILITY AB The properties of metallic products and semiconductors are determined by the melt composition and the micro- and macrostructure development during solidification. Heat and mass transfer by diffusion and convection determine the phase change liquid/solid. Experiments concerning the influence of convection on solidifying melts were performed in the range between 0.001 g and 1 g. Deeper insight into the convective transport during solidification was achieved by using transparent model systems behaving similar to metals. As expected, thermal convection due to parasitic gradients tilted to the solidification direction could be reduced drastically. In the experiments the melt was more stable against the onset of thermal convection than predicted by models. C1 RHEIN WESTFAL TH AACHEN,GIESSEREI INST,D-52072 AACHEN,GERMANY. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Leonartz, K (reprint author), INGENIEURBURO,EIFELSTR 41,D-52068 AACHEN,GERMANY. NR 40 TC 0 Z9 0 U1 0 U2 0 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 860420, W-8163 MUNICH, GERMANY SN 0044-3093 J9 Z METALLKD JI Z. Metallk. PD APR PY 1997 VL 88 IS 4 BP 291 EP 300 PG 10 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA XA157 UT WOS:A1997XA15700004 ER PT J AU Yu, JW Douglas, JF Hobbie, EK Kim, S Han, CC AF Yu, JW Douglas, JF Hobbie, EK Kim, S Han, CC TI Shear-induced ''homogenization'' of a diluted polymer blend SO PHYSICAL REVIEW LETTERS LA English DT Article ID SEMIDILUTE SOLUTION; LIGHT-SCATTERING; CRITICAL-POINT; MIXTURE; RENORMALIZATION; FLUIDS; FLOW AB The miscibility of a diluted polymer blend under steady shear has been investigated in the two-phase region using fluorescence and phase-contrast microscopy. Critical exponents describing the shape of the coexistence curve and the shift of the critical temperature Delta T-c(gamma) were compatible with expectations based on renormalization group and mode-coupling theories, but the introduction of a reduced variable description of Delta T-c suggested a tendency for T-c to saturate at high shear rates. RP Yu, JW (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. RI Hobbie, Erik/C-8269-2013 NR 20 TC 35 Z9 35 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 31 PY 1997 VL 78 IS 13 BP 2664 EP 2667 DI 10.1103/PhysRevLett.78.2664 PG 4 WC Physics, Multidisciplinary SC Physics GA WQ502 UT WOS:A1997WQ50200042 ER PT J AU Phillips, WD Westbrook, CI AF Phillips, WD Westbrook, CI TI Observation of temporal behavior of an atomic wave packet localized in an optical potential - Comment SO PHYSICAL REVIEW LETTERS LA English DT Article C1 INST OPT,URA 14 CNRS,F-91403 ORSAY,FRANCE. RP Phillips, WD (reprint author), NATL INST STAND & TECHNOL,PHY A267,GAITHERSBURG,MD, USA. RI Westbrook, Christoph/B-6092-2009 OI Westbrook, Christoph/0000-0002-6490-0468 NR 8 TC 12 Z9 12 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAR 31 PY 1997 VL 78 IS 13 BP 2676 EP 2676 DI 10.1103/PhysRevLett.78.2676 PG 1 WC Physics, Multidisciplinary SC Physics GA WQ502 UT WOS:A1997WQ50200045 ER PT J AU Nastrom, GD VanZandt, TE Warnock, JM AF Nastrom, GD VanZandt, TE Warnock, JM TI Vertical wavenumber spectra of wind and temperature from high-resolution balloon soundings over Illinois SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GRAVITY-WAVE SPECTRA; MIDDLE ATMOSPHERE; LOWER STRATOSPHERE; PERTURBATION SPECTRA; UNIVERSAL SPECTRUM; MOMENTUM FLUXES; PROFILES; SATURATION; SHEAR; FLUCTUATIONS AB We spectrally analyzed high-resolution balloon measurements of vertical profiles of temperature and horizontal wind in the troposphere and lower stratosphere over very flat terrain in Illinois. This paper is principally concerned with spectra in the power law range at vertical wavenumbers m greater than or similar to 10(-3) cycle/m. The logarithmic spectral slopes and amplitudes are found to have only insignificant dependencies on meteorological parameters, including time of day, season, wind speed and direction, vertical shear, etc., except that between the troposphere and stratosphere the spectral amplitude scales as (N-2)(q) with q similar to 0.3, where N is the buoyancy frequency. The mean slopes are approximate to -3 in the stratosphere and approximate to -2.6 in the troposphere. On the average the individual spectra with larger amplitudes have less negative spectral slopes. The wide variation of spectral slopes (sigma approximate to 0.5) and amplitudes and the weak dependence on N-2 are quite inconsistent with the predictions of theories of saturated spectra. Further, the wind spectra in the troposphere and stratosphere are correlated, which suggests some unsaturated propagation between the regions. The ratio of kinetic to potential energy spectra is constant versus m, consistent with the linear gravity wave polarization relations. The magnitude of the model ratio can be brought into agreement with the observed ratio by assuming a model intrinsic frequency spectrum varying as omega(-p) with p similar to 5/3 to 2 plus an enhancement of energy near the inertial frequency. C1 NOAA, AERON LAB, BOULDER, CO 80303 USA. RP Nastrom, GD (reprint author), ST CLOUD STATE UNIV, DEPT EARTH SCI, ST CLOUD, MN 56301 USA. NR 53 TC 57 Z9 59 U1 1 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 MAR 27 PY 1997 VL 102 IS D6 BP 6685 EP 6701 DI 10.1029/96JD03784 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WR433 UT WOS:A1997WR43300005 ER PT J AU Mo, KC Dickey, JO Marcus, SL AF Mo, KC Dickey, JO Marcus, SL TI Interannual fluctuations in atmospheric angular momentum simulated by the national centers for environmental prediction medium range forecast model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOUTHERN OSCILLATION; HADLEY CIRCULATION; CLIMATE; SCALES; SYSTEM AB An earlier study by Dickey et al. [1992] established the existence of globally coherent interannual fluctuations in atmospheric angular momentum (AAM), associated with the El Nino-Southern Oscillation (ENSO) cycle. In this paper, we pursue the origin and the structure of these fluctuations using an ensemble of experiments generated by the National Centers for Environmental Prediction, medium range forecast model version 9. In the control experiments, where the observed sea surface temperatures (SSTs) were used as the lower boundary conditions, the model captures the characteristic V-like structure in time-latitude plots of zonally averaged AAM found by Dickey et al., while experiments with climatological SSTs and those with either perpetual warm or cold ENSO conditions superimposed on the climatological SSTs failed to reproduce this structure. The numerical results indicate that these AAM structures are related to SST variations associated with transitions between different phases of the ENSO cycle and have both propagating and standing components. The largest zonal wind contribution from the levels studied (850, 500, and 200 hPa) is at 200 hPa, where the tropical convective outflow is the strongest. Composites of zonal wind and geopotential height show a clear relationship between the stages of the global AAM oscillation and the ENSO cycle. The strong similarity between the simulated and observed AAM series attests to the model's ability to realistically simulate the interannual response of the atmosphere to ENSO SST anomalies. C1 CALTECH, JET PROP LAB, SPACE GEODET SCI & APPL GRP, PASADENA, CA 91109 USA. RP Mo, KC (reprint author), NOAA, NATL WEATHER SERV, NCEP, CLIMATE PREDICT CTR, WASHINGTON, DC 20233 USA. OI Marcus, Steven/0000-0002-5763-6961 NR 34 TC 11 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 27 PY 1997 VL 102 IS D6 BP 6703 EP 6713 DI 10.1029/96JD02609 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WR433 UT WOS:A1997WR43300006 ER PT J AU Bishop, JKB Rossow, WB Dutton, EG AF Bishop, JKB Rossow, WB Dutton, EG TI Surface solar irradiance from the International Satellite Cloud Climatology Project 1983-1991 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NORTH-ATLANTIC OCEAN; SHORTWAVE RADIATION; ISCCP; SEA; VARIABILITY; TEMPERATURE; PRODUCTS; MODELS AB An 8 year (July 1983 through June 1991) time series of daily and monthly mean surface solar irradiance has been produced for the globe using data from the International Satellite Cloud Climatology Project (ISCCP) and a revised Bishop and Rossow [1991] algorithm. We present a detailed validation analysis of the ISCCP solar irradiance fields with contemporaneous surface observations at buoys, at remote islands, and from the Global Energy Balance Archives (GEBA) [Ohmura et al., 1991]. The validation is hampered to some degree by the scale difference between the 280 km ISCCP product and the single-point measurements, some of which are affected by orographic clouds and other local meteorological effects. Our analysis suggests criteria for siting of island or coastal monitoring locations to minimize such biases. Particularly, eastward or poleward facing oceanic exposures are to be avoided. In addition, we suggest that deep sea buoys should be investigated for validation of oceanic surface fluxes. At open-ocean, clean-air sites, the ISCCP product is shown to be good to within 10 W m(-2) in the monthly mean. The high-frequency (daily) systematics of solar irradiance variability at the open-ocean sites are also well duplicated by the ISCCP product. An identifiable error in the revised solar irradiance product is the neglect of spatially and temporally varying aerosol extinction. This error, when translated into an equivalent aerosol extinction coefficient, can be as large as 0.6 in known polluted and mineral dust-affected regions. We cannot determine additional satellite sensor calibration errors beyond those already corrected in the ISCCP processing This uniquely long data set has been publicly available since 1994 at the National Center for Atmospheric Research. The data documents significant differences in solar fluxes received by the major oceans as well as significant flux variability on seasonal to interannual timescales. C1 UNIV VICTORIA, SCH EARTH & OCEAN SCI, VICTORIA, BC, CANADA. NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. RP Bishop, JKB (reprint author), NASA, GODDARD SPACE FLIGHT CTR, INST SPACE STUDIES, NEW YORK, NY 10025 USA. RI Rossow, William/F-3138-2015 NR 51 TC 69 Z9 70 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 27 PY 1997 VL 102 IS D6 BP 6883 EP 6910 DI 10.1029/96JD03865 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WR433 UT WOS:A1997WR43300017 ER PT J AU Pinto, JO Curry, JA Fairall, CW AF Pinto, JO Curry, JA Fairall, CW TI Radiative characteristics of the Arctic atmosphere during spring as inferred from ground-based measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DELTA-EDDINGTON APPROXIMATION; SOLAR-RADIATION; STRATUS CLOUDS; MULTIPLE-SCATTERING; CLIMATE FEEDBACK; WATER CLOUDS; MODEL; PARAMETERIZATION; BUDGETS AB The radiative characteristics of low-level clouds over the Arctic ice pack in spring are inferred from ground-based broadband flux measurements using a radiative transfer model. An informal comparison of several radiative transfer models is performed for clear-sky conditions observed in April during LEADEX. The broadband longwave and shortwave surface fluxes obtained with Streamer and the broadband longwave surface flux obtained with the Rapid Radiative Transfer Model (RRTM) correlate well with the observations. The Streamer code is chosen to determine cloud optical and microphysical properties based on its performance under clear-sky conditions, its sophisticated treatment of clouds, and its option for calculating fluxes using a discrete ordinate technique. The radiative properties of the Arctic atmosphere are complicated by the presence of clouds. Low clouds occurred 30% of the time during LEADEX. The longwave and shortwave optical depths of clouds based below 2 km are inferred from surface-based measurements of cloud base height and broadband radiative fluxes by matching the observed fluxes with those obtained with the four-stream radiative transfer code available as part of Streamer. The retrieved broadband shortwave and longwave optical depths for low clouds observed during LEADEX ranged between 0.2 and 3. An attempt is made to infer cloud phase and cloud particle size from the ratio of the retrieved broadband shortwave and longwave cloud optical depths. This ratio ranges from 1.33 to 1.75 for ice, from 0.85 to 1.9 for liquid, and from 0.85 to 1.9 for mixed-phase clouds. Although there is much overlap between the ranges, it is shown that liquid-water clouds are characterized by optical depth ratios that are generally smaller than those found in ice clouds. This method for inferring cloud microphysics from surface-based measurements of broadband radiative fluxes and cloud base height may prove useful where more sophisticated observations of cloud microphysics are lacking. C1 NOAA, ERL, ENVIRONM TECHNOL LAB, BOULDER, CO 80303 USA. RP Pinto, JO (reprint author), UNIV COLORADO, PROGRAM ATMOSPHER & OCEAN SCI, BOULDER, CO 80309 USA. NR 39 TC 32 Z9 32 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 27 PY 1997 VL 102 IS D6 BP 6941 EP 6952 DI 10.1029/96JD03348 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WR433 UT WOS:A1997WR43300020 ER PT J AU Douglas, JF Freed, KF AF Douglas, JF Freed, KF TI Modification of continuum chain model of surface-interacting polymers to describe the crossover between weak and strong adsorption SO MACROMOLECULES LA English DT Article ID RENORMALIZATION-GROUP; EXCLUDED VOLUME; FLEXIBLE POLYMERS; MONTE-CARLO; MACROMOLECULES AB Continuum models of flexible polymers give physically incorrect results in situations where polymers are ''localized'' to restricted regions of space. Limitations of continuum chain theories for confined polymers are illustrated for surface-interacting polymers where both lattice and continuum calculations can be performed exactly for ideal chains. This comparison reveals the details of the breakdown of the continuum chain model in the regime of strong polymer adsorption. As a remedy to this difficulty, we formally introduce a corrected continuum chain theory by taking the spatial dimension d to depend on the surface interaction in such a way that the lattice and continuum model calculations are required to be consistent for weak and strong polymer adsorption. C1 UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637. RP Douglas, JF (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 24 TC 8 Z9 8 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAR 24 PY 1997 VL 30 IS 6 BP 1813 EP 1817 DI 10.1021/ma961007x PG 5 WC Polymer Science SC Polymer Science GA WP909 UT WOS:A1997WP90900040 ER PT J AU Rye, BJ Hardesty, RM AF Rye, BJ Hardesty, RM TI Detection techniques for validating Doppler estimates in heterodyne lidar SO APPLIED OPTICS LA English DT Article ID SPECTRAL PEAK ESTIMATION; VELOCITY ESTIMATION; ACCUMULATION; RADAR AB We investigate the ability of detection techniques based on the likelihood ratio to discriminate between heterodyne lidar Doppler estimates at low signal levels using examples generated by simulation. The distinction between estimates that are regarded as acceptable and as spurious is based on the Cramer-Rao lower bound. The conditional false alarm probability, which ordinarily describes recording detection of a signal when none is present, is then found to be an approximate upper bound on the probability of selection of a spurious estimate. The method is superior theoretically to similar techniques based on detection functions other than the likelihood ratio. The likelihood ratio also provides a basis for reprocessing rejected data in the light of contextual information provided by those estimates that are accepted. (C) 1997 Optical Society of America. C1 NOAA,ENVIRONM TECHNOL LAB,BOULDER,CO 80303. RP Rye, BJ (reprint author), UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,ENVIRONM TECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Hardesty, Robert/H-9844-2013 NR 21 TC 22 Z9 25 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAR 20 PY 1997 VL 36 IS 9 BP 1940 EP 1951 DI 10.1364/AO.36.001940 PG 12 WC Optics SC Optics GA WN598 UT WOS:A1997WN59800015 PM 18250885 ER PT J AU Lynn, JW AF Lynn, JW TI Rare earth magnetic ordering in exchange-coupled superconductors SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 21st Rare Earth Research Conference CY JUL 07-12, 1996 CL DULUTH, MN SP Rare Earth Res Conf Inc, Univ Minnesota, USR Optonix Inc, Amer Chem Soc, Petr Res Fund, Arris Int Corp, Baotou Steel & Rare Earth Co, US DE rare earth; magnetic order; superconductivity; exchange interactions; neutron scattering ID NICKEL BORIDE CARBIDES; ANTIFERROMAGNETIC ORDER; NEUTRON-DIFFRACTION; B-C; PR; PRBA2CU3O7; HONI2B2C; DYNI2B2C; SUSCEPTIBILITY; STATE AB Magnetic neutron diffraction measurements are reviewed for two families of superconductors where exchange interactions dominate the energetics of the magnetic system. One system is cuprates that contain Pr, which exhibit magnetic rare earth ordering temperatures that are an order-of-magnitude higher than for the other rare earths, and where f-electron hybridization effects destroy any chance for superconductivity. The second family of materials is the quaternary RNi2B2C borocarbides. These materials have comparable magnetic and superconducting transition temperatures, and exhibit a rich variety of commensurate and incommensurate magnetic structures that coexist and compete with the superconducting state. C1 UNIV MARYLAND,CTR SUPERCONDUCT RES,COLLEGE PK,MD 20742. RP Lynn, JW (reprint author), NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899, USA. NR 57 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAR 20 PY 1997 VL 250 IS 1-2 BP 552 EP 558 DI 10.1016/S0925-8388(96)02634-5 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA XD794 UT WOS:A1997XD79400055 ER PT J AU Ciais, P Denning, AS Tans, PP Berry, JA Randall, DA Collatz, GJ Sellers, PJ White, JWC Trolier, M Meijer, HAJ Francey, RJ Monfray, P Heimann, M AF Ciais, P Denning, AS Tans, PP Berry, JA Randall, DA Collatz, GJ Sellers, PJ White, JWC Trolier, M Meijer, HAJ Francey, RJ Monfray, P Heimann, M TI A three-dimensional synthesis study of delta O-18 in atmospheric CO2 .1. Surface fluxes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; ISOTOPIC COMPOSITION; BOUNDARY-LAYER; STOMATAL CONDUCTANCE; SPATIAL VARIATION; CARBON-DIOXIDE; WATER-VAPOR; OXYGEN; O-18; FRACTIONATION AB The isotope O-18 in CO2 is of particular interest in studying the global carbon cycle because it is sensitive to the processes by which the global land biosphere absorbs and respires CO2. Carbon dioxide and water exchange isotopically both in leaves and in soils, and the O-18 character of atmospheric CO2 is strongly influenced by the land biota, which should constrain the gross primary productivity and total respiration of land ecosystems, In this study we calculate the global surface fluxes of O-18 for vegetation and soils using the SiB2 biosphere model coupled with the Colorado State University general circulation model. This approach makes it possible to use physiological variables that are consistently weighted by the carbon assimilation rate and integrated through the vegetation canopy, We also calculate the air-sea exchange of O-18 and the isotopic character of fossil emissions and biomass burning. Global mean values of the isotopic exchange with each reservoir are used to close the global budget of O-18 in CO2 results confirm the fact that the land biota exert a dominant control on the delta(18)O of the atmospheric reservoir, At the global scale, exchange with the canopy produces an isotopic enrichment of CO2, whereas exchange with soils has the opposite effect. C1 CARNEGIE INST WASHINGTON, DEPT PLANT BIOL, STANFORD, CA 94305 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. CSIRO, DIV ATMOSPHER RES, MELBOURNE, VIC 3195, AUSTRALIA. MAX PLANCK INST METEOROL, D-20146 HAMBURG, GERMANY. UNIV GRONINGEN, CIO, NL-9722 JX GRONINGEN, NETHERLANDS. CTR FAIBLES RADIOACT, LMCE, F-91191 GIF SUR YVETTE, FRANCE. UNIV COLORADO, INST ARCTIC & ALPINE RES, BOULDER, CO 80303 USA. NOAA, ERL 3, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. RP Ciais, P (reprint author), CEA ORME MERISIERS, LMCE, COMMISSARIAT ENERGIE ATOM, BATIMENT 709, F-91191 GIF SUR YVETTE, FRANCE. RI Berry, Joseph/B-8211-2009; White, James/A-7845-2009; Meijer, Harro/A-5787-2012; collatz, george/D-5381-2012; Denning, Scott/F-4974-2011; Randall, David/E-6113-2011; Heimann, Martin/H-7807-2016 OI Berry, Joseph/0000-0002-5849-6438; White, James/0000-0001-6041-4684; Denning, Scott/0000-0003-3032-7875; Randall, David/0000-0001-6935-4112; Heimann, Martin/0000-0001-6296-5113 NR 64 TC 156 Z9 162 U1 4 U2 19 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 1997 VL 102 IS D5 BP 5857 EP 5872 DI 10.1029/96JD02360 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100001 ER PT J AU Ciais, P Tans, PP Denning, AS Francey, RJ Trolier, M Meijer, HAJ White, JWC Berry, JA Randall, DA Collatz, GJ Sellers, PJ Monfray, P Heimann, M AF Ciais, P Tans, PP Denning, AS Francey, RJ Trolier, M Meijer, HAJ White, JWC Berry, JA Randall, DA Collatz, GJ Sellers, PJ Monfray, P Heimann, M TI A three-dimensional synthesis study of delta O-18 in atmospheric CO2 .2. Simulations with the TM2 transport model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CARBON-DIOXIDE; EXCHANGE AB In this study, using a three-dimensional (3-D) tracer modeling approach, we simulate the delta(18)O of atmospheric CO2. In the atmospheric transport model TM2 we prescribe the surface fluxes of O-18 due to vegetation and soils, ocean exchange, fossil emissions, and biomass burning. The model simulations are first discussed for each reservoir separately, then all the reservoirs are combined to allow a comparison with the atmospheric delta(18)O measurements made by the National Oceanic and Atmospheric Administration-University of Colorado, Scripps Institution of Oceanography-Centrum Voor Isotopen Onderzoek (United States-Netherlands) and Commonwealth Scientific and Industrial Research Organisation (Australia) air sampling programs, Insights into the latitudinal differences and into the seasonal cycle of delta(18)O in CO2 are gained by looking at the contribution of each source, The isotopic exchange with soils induces a large isotopic depletion over the northern hemisphere continents, which overcomes the concurrent effect of isotopic enrichment due to leaf exchange, Compared to the land biota, the ocean fluxes and the anthropogenic CO2 source have a relatively minor influence, The shape of the latitudinal profile in delta(18)O appears determined primarily by the respiration of the land biota, which balances photosynthetic uptake over the course of a year, Additional information on the phasing of the terrestrial carbon exchange comes from the seasonal cycle of delta(18)O at high northern latitudes. C1 CARNEGIE INST WASHINGTON, DEPT PLANT BIOL, STANFORD, CA 94305 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. CSIRO, DIV ATMOSPHER RES, MELBOURNE, VIC 3195, AUSTRALIA. MAX PLANCK INST METEOROL, D-20146 HAMBURG, GERMANY. UNIV GRONINGEN, CIO, NL-9722 JX GRONINGEN, NETHERLANDS. CTR FAIBLES RADIOACT, LMCE, F-91191 GIF SUR YVETTE, FRANCE. NOAA, ERL 3, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. UNIV COLORADO, INST ARCTIC & ALPINE RES, BOULDER, CO 80303 USA. RP Ciais, P (reprint author), CEA ORME MERISIERS, LMCE, BATIMENT 709, F-91191 GIF SUR YVETTE, FRANCE. RI Berry, Joseph/B-8211-2009; White, James/A-7845-2009; Meijer, Harro/A-5787-2012; collatz, george/D-5381-2012; Denning, Scott/F-4974-2011; Randall, David/E-6113-2011; Heimann, Martin/H-7807-2016 OI Berry, Joseph/0000-0002-5849-6438; White, James/0000-0001-6041-4684; Denning, Scott/0000-0003-3032-7875; Randall, David/0000-0001-6935-4112; Heimann, Martin/0000-0001-6296-5113 NR 24 TC 59 Z9 60 U1 1 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 20 PY 1997 VL 102 IS D5 BP 5873 EP 5883 DI 10.1029/96JD02361 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100002 ER PT J AU Zhao, CL Tans, PP Thoning, KW AF Zhao, CL Tans, PP Thoning, KW TI A high precision manometric system for absolute calibrations of CO2 in dry air SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CARBON-DIOXIDE AB A high-precision manometric system has been developed for absolute calibrations of CO2-in-air mixture gas. This report describes the principle of the calibration method and evaluates the performance of the manometric apparatus. The test results show that the reproducibility of the manometric system for calibrating CO2-in-air gas mixtures is within +/-0.1 mu mol mol(-1) in the atmospheric CO2 concentration range of 300 to 400 mu mol mol(-1). Preliminary measurements indicate that the agreement with the absolute World Meteorological Organization mole fraction scale, widely used for atmospheric CO2 monitoring, is also within +/-0.1 mu mol mol(-1) in that same range. C1 NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. RP Zhao, CL (reprint author), UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. NR 14 TC 45 Z9 45 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 20 PY 1997 VL 102 IS D5 BP 5885 EP 5894 DI 10.1029/96JD03764 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100003 ER PT J AU Olson, J Prather, M Berntsen, T Carmichael, G Chatfield, R Connell, P Derwent, R Horowitz, L Jin, SX Kanakidou, M Kasibhatla, P Kotamarthi, R Kuhn, M Law, K Penner, J Perliski, L Sillman, S Stordal, F Thompson, A Wild, O AF Olson, J Prather, M Berntsen, T Carmichael, G Chatfield, R Connell, P Derwent, R Horowitz, L Jin, SX Kanakidou, M Kasibhatla, P Kotamarthi, R Kuhn, M Law, K Penner, J Perliski, L Sillman, S Stordal, F Thompson, A Wild, O TI Results from the Intergovernmental Panel on Climatic Change Photochemical Model Intercomparison (PhotoComp) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OH CONCENTRATIONS; OZONE PRODUCTION; ATMOSPHERE; MECHANISM; NITROGEN; KINETICS; STRATOSPHERE; TROPOSPHERE; OXIDES; FIELD AB Results from the Intergovernmental Panel on Climatic Change (IPCC) tropospheric photochemical model intercomparison (PhotoComp) are presented with a brief discussion of the factors that may contribute to differences in the modeled behaviors of HOx cycling and the accompanying O-3 tendencies. PhotoComp was a tightly controlled model experiment in which the IPCC 1994 assessment sought to determine the consistency among models that are used to predict changes in tropospheric ozone, an important greenhouse gas, Calculated tropospheric photodissociation rates displayed significant differences, with a root-mean-square (rms) error of the reported model results ranging from about +/-6-9% of the mean (for O-3 and NO2) to up to +/-15% (H2O2 and CH2O). Models using multistream methods in radiative transfer calculations showed distinctly higher rates for photodissociation of NO2 and CH2O compared to models using two-stream methods, and this difference accounted for up to one third of the rms error for these two rates, In general, some small but systematic differences between models were noted for the predicted chemical tendencies in cases that did not include reactions of nonmethane hydrocarbons (NMHC). These differences in modeled O-3 tendencies in some cases could be identified, for example, as being due to differences in photodissociation rates, but in others they could not and must be ascribed to unidentified errors. O-3 tendencies showed rms errors of about +/-10% in the moist, surface level cases with NOx concentrations equal to a few tens of parts per trillion by volume. Most of these model to model differences can be traced to differences in the destruction of O-3 due to reaction with HO2. Differences in HO2, in turn, are likely due to (1) inconsistent reaction rates used by the models for the conversion of HO2 to H2O2 and (2) differences in the model-calculated photolysis of H2O2 and CH2O. In the middle tropospheric ''polluted'' scenario with NOx concentrations larger than a few parts per billion by volume, O-3 tendencies showed rms errors of +/-10-30%. These model to model differences most likely stem from differences in the calculated rates of O-3 photolysis to O(D-1), which provides about 80% of the HOx source under these conditions. The introduction of hydrocarbons dramatically increased both the rate of NOx loss and its model to model differences, which, in turn, are reflected in an increased spread of predicted O-3. Including NMHC in the simulation approximately doubled the rms error for O-3 concentration. C1 UNIV OSLO, N-1305 OSLO, NORWAY. UNIV IOWA, IOWA CITY, IA 52240 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. METEOROL OFF, BRACKNELL RG12 2SZ, BERKS, ENGLAND. HARVARD UNIV, CAMBRIDGE, MA 02138 USA. NEW YORK STATE DEPT TRANSPORTAT, NEW YORK, NY 12232 USA. CTR FAIBLES RADIOACT, GIF SUR YVETTE, FRANCE. MCNC, ENVIRONM PROGRAMS, RES TRIANGLE PK, NC 27709 USA. ATMOSPHER & ENVIRONM RES INC, CAMBRIDGE, MA 02139 USA. FRAUNHOFER INST ATMOSPHAR UMWELTFORSCH, D-82467 GARMISCH PARTENKIRCHEN, GERMANY. UNIV CAMBRIDGE, CAMBRIDGE CB2 1EW, ENGLAND. NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08542 USA. UNIV CALIF IRVINE, IRVINE, CA 92717 USA. UNIV MICHIGAN, ANN ARBOR, MI 48109 USA. NORWEGIAN INST AIR RES, N-2007 KJELLER, NORWAY. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP Olson, J (reprint author), NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. RI Wild, Oliver/A-4909-2009; Kasibhatla, Prasad/A-2574-2010; Kanakidou, Maria/D-7882-2012; Horowitz, Larry/D-8048-2014; Garmisch-Pa, Ifu/H-9902-2014; Thompson, Anne /C-3649-2014; OI Wild, Oliver/0000-0002-6227-7035; Kanakidou, Maria/0000-0002-1724-9692; Horowitz, Larry/0000-0002-5886-3314; Thompson, Anne /0000-0002-7829-0920; Sillman, Sanford/0000-0001-6250-1191; Stordal, Frode/0000-0002-5190-6473; Derwent, Richard/0000-0003-4498-645X; Kasibhatla, Prasad/0000-0003-3562-3737 NR 34 TC 54 Z9 54 U1 1 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 MAR 20 PY 1997 VL 102 IS D5 BP 5979 EP 5991 DI 10.1029/96JD03380 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100011 ER PT J AU Martin, D Tsivou, M Bonsang, B Abonnel, C Carsey, T SpringerYoung, M Pszenny, A Suhre, K AF Martin, D Tsivou, M Bonsang, B Abonnel, C Carsey, T SpringerYoung, M Pszenny, A Suhre, K TI Hydrogen peroxide in the marine atmospheric boundary layer during the Atlantic Stratocumulus Transition Experiment Marine Aerosol and Gas Exchange Experiment in the eastern subtropical North Atlantic SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ASTEX LAGRANGIAN EXPERIMENTS; NORTHEASTERN UNITED-STATES; TROPOSPHERIC CHEMISTRY; AIRCRAFT MEASUREMENTS; ACID GENERATION; H2O2; OZONE; PHASE; CLOUD; AIR AB Gas phase H2O2 was measured in surface air on the NOAA ship Malcolm Baldrige from June 8 to 27, 1992 (Julian days 160-179), during the Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange experiment in the eastern subtropical North Atlantic region. Average H2O2 mixing ratios observed were 0.63 +/- 0.28 ppbv, ranging between detection limit and 1.5 ppbv. For the entire experiment, only weak or no correlation was found between H2O2 mixing ratio and meteorological parameters (pressure, temperature, humidity, or UV radiation flux) as well as with tracers of continental air masses (CO, black carbon, radon), The average daily H2O2 cycle for the entire period exhibits a maximum of 0.8 +/- 0.3 ppbv near sunset and a minimum of 0.4 +/- 0.2 ppbv 4-5 hours after sunrise, Several clear H2O2 diurnal variations have been observed, from which a first-order removal rate of about 1 x 10(-5) s(-1) for H2O2 can be inferred from nighttime measurements, This rate compares well with those deduced from measurements taken at Cape Grim (Tasmania, 41 degrees S) and during the Soviet-American Gas and Aerosol III experiment (equatorial Pacific Ocean). C1 CTR NATL RECH METEOROL, CTR AVIAT METEOROL, F-91128 BRETIGNY SUR ORGE, FRANCE. CNRS, CTR FAIBLES RADIO ACTIV, F-91198 GIF SUR YVETTE, FRANCE. NOAA, ATLANTIC OCEANOG & METEOROL LAB, MIAMI, FL 33149 USA. MIT, IGAC, CORE PROJECT OFF, CAMBRIDGE, MA 02139 USA. OBSERV MIDI PYRENEES, UMR CNRS, UPS 5560, LAB AEROL, F-31400 TOULOUSE, FRANCE. RP Martin, D (reprint author), CNRS, CTR FAIBLES RADIO ACTIV, BATIMENT 709, F-91198 GIF SUR YVETTE, FRANCE. RI Carsey, Thomas/B-7939-2014; OI Carsey, Thomas/0000-0001-9964-5092; Suhre, Karsten/0000-0001-9638-3912 NR 61 TC 18 Z9 19 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 1997 VL 102 IS D5 BP 6003 EP 6015 DI 10.1029/96JD03056 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100013 ER PT J AU Carmichael, GR Hong, MS Ueda, H Chen, LL Murano, K Park, JK Lee, HG Kim, Y Kang, C Shim, S AF Carmichael, GR Hong, MS Ueda, H Chen, LL Murano, K Park, JK Lee, HG Kim, Y Kang, C Shim, S TI Aerosol composition at Cheju Island, Korea SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; PACIFIC-OCEAN; CONTINENTAL SOURCES; ASIA; SO2; NOX; EMISSIONS; TRANSPORT; NITRATE; ACID AB The seasonal variation in chemical composition of aerosols measured at Cheju Island, Korea, is presented and discussed. Daily tape filters have been obtained for the three year period analyzed March 1992 through February 1995. The annual average non-sea-salt sulfate and nitrate mass concentrations of aerosols measured at Cheju, are 7.2 mu g/m(3) and 1.2 mu g/m(3), respectively; while calcium and potassium are present in nearly equal amounts of similar to 0.5 mu g/m(3), and ammonium averages 1.3 mu g/m(3). The annual mean mass ratios are SO42-/NO3- = 6.2. NH4+/SO42- = 0.2, Ca2+/Na+ = 0.3, and NH4/NO3- = 1.1. Each species is found to follow a seasonal cycle, with sulfate, nitrate, ammonium, potassium, and calcium all showing higher values in the spring. In contrast, chlorine concentrations are 10% lower in the spring. Aerosol enrichment factors relative to the composition of seawater and crustal material from the dust-source regions in central China reveal that the aerosol measured at Cheju is enriched in sulfate, nitrate, and ammonium, but is deficient in chlorine (relative to seawater). The data from the daily tape filters are also compared with those from weekly Hi-Vol filters located at the same site and other measurements in the region. C1 AJOU UNIV, ENVIRONM SCI & ENGN RES INST, SUWON 441749, SOUTH KOREA. CHEJU UNIV, DEPT CHEM, CHEJU, SOUTH KOREA. NOAA, BOULDER, CO 80303 USA. KOREA INST SCI & TECHNOL, SYST ENGN RES INST, TAEJON, SOUTH KOREA. NATL INST ENVIRONM STUDIES, TSUKUBA, IBARAKI 305, JAPAN. KOREA INST SCI & TECHNOL, ENVIRONM RES CTR, SEOUL 136791, SOUTH KOREA. KYUSHU UNIV, APPL MECH RES INST, KASUGA, FUKUOKA 816, JAPAN. RP Carmichael, GR (reprint author), UNIV IOWA, CTR GLOBAL & REG ENVIRONM RES, IOWA CITY, IA 52242 USA. RI Kyushu, RIAM/F-4018-2015; U-ID, Kyushu/C-5291-2016 NR 32 TC 109 Z9 112 U1 2 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 20 PY 1997 VL 102 IS D5 BP 6047 EP 6061 DI 10.1029/96JD02961 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100017 ER PT J AU Mount, GH Williams, EJ AF Mount, GH Williams, EJ TI An overview of the tropospheric OH photochemistry experiment, Fritz Peak Idaho Hill, Colorado, Fall 1993 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NIWOT RIDGE; ABSORPTION; CHEMISTRY; NOY AB `An extensive study of tropospheric photochemical trace species, including the hydroxyl radical OH was conducted in the Colorado Rocky Mountains from early August to early October 1993. Many of the parameters that influence the abundance of OH in the atmosphere, including j(O-3 and NO2), formaldehyde, nonmethane hydrocarbons, NOx, ozone, H2O, aerosols, and others, were measured simultaneously with OH. Instrumentation for measurement of OH included a long-path spectroscopic technique and several in situ techniques: ion-assisted mass spectrometry, laser-induced resonance fluorescence, and a liquid scrubber/liquid chromatographic method. Instrument comparisons between long-path and in situ measurements were conducted for OH, O-3, CH2O, NO2, and H2O, and these measurements provide a valuable insight into the chemistry of the region. The complete data set provided a robust set of inputs to a zero-dimensional model for exploring OH photochemistry. Independently measured OH concentrations were in agreement within one standard error much of the time, thus giving confidence that hydroxyl is being measured correctly. OH concentrations were typically low during clean continental airflow with concentrations rarely above 4 x 10(6) cm(-3). During occasions of polluted airflow from the Denver-Boulder metropolitan areas, values of OH rose as high as 1.2 x 10(7) cm(-3). The nearly complete suite of trace gases measured simultaneously with the hydroxyl radical severely constrained the models and provided numerous opportunities to compare relations between species (e.g. OH versus NOx, OH/HO2, RO(2) versus NOx). Modeled hydroxyl results using the complete species suite were about a factor of 1.5 higher than measured OH concentrations suggesting that the photochemistry may not be well understood. The campaign data provide new insights into the chemistry of the lower troposphere. This paper provides an overview of the campaign and brief descriptions of results from individual experiments. Details are provided in the accompanying papers in this issue. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Mount, GH (reprint author), NOAA, AERON LAB, 325 BROADWAY, BOULDER, CO 80303 USA. RI Williams, Eric/F-1184-2010 NR 21 TC 32 Z9 32 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 20 PY 1997 VL 102 IS D5 BP 6171 EP 6186 DI 10.1029/96JD00693 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100028 ER PT J AU Olson, JA Baumann, K Volpe, CJ Harder, JW Williams, EJ Mount, GH AF Olson, JA Baumann, K Volpe, CJ Harder, JW Williams, EJ Mount, GH TI Meteorological overview of the 1993 OH photochemistry experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BOUNDARY-LAYER EVOLUTION; REGIONAL-SCALE FLOWS; MOUNTAINOUS TERRAIN; NIWOT-RIDGE; COLORADO; CLIMATE AB Meteorological data from three weather stations in the Fritz Peak region of the Colorado Front Range are presented to aid in the interpretation of photochemical results from the tropospheric OH Photochemistry Experiment. The field site, its surrounding topography, and pollution sources are described. Meteorological data show a transition during the campaign from the summer into the fall season, marked by decreasing temperatures and cloud cover, along with increasing wind speeds and westerly flow. Mountainous terrain significantly influences the meteorology over the site and thereby complicates the comparisons of chemical measurements. The meteorological data suggest that an appropriate time to make comparisons between measurement techniques is under conditions of strong westerly airflow, though synchronous upslope wind events should not be excluded. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Olson, JA (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E-AL5, BOULDER, CO 80303 USA. RI Williams, Eric/F-1184-2010 NR 17 TC 0 Z9 0 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 1997 VL 102 IS D5 BP 6187 EP 6197 DI 10.1029/96JD00402 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100029 ER PT J AU Baumann, K Williams, EJ Olson, JA Harder, JW Fehsenfeld, FC AF Baumann, K Williams, EJ Olson, JA Harder, JW Fehsenfeld, FC TI Meteorological characteristics and spatial extent of upslope events during the 1993 Tropospheric OH Photochemistry Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID REGIONAL-SCALE FLOWS; BOUNDARY-LAYER EVOLUTION; MOUNTAINOUS TERRAIN; NIWOT-RIDGE; COLORADO; OZONE AB A detailed study of mountain-valley circulation at the Front Range, west of Boulder, Colorado, during the transition period from summer to fall has been conducted using an extensive chemical and meteorological data set. This set was collected during the Tropospheric OH Photochemistry Experiment (TOHPE) in August and September 1993. One major objective of TOHPE was to compare chemical trace gas concentrations measured simultaneously by a long-path (10.3 km) absorption spectrometer and by various in situ methods that were located at the ends of the long-path beam. Generally, the study area experienced clean westerly flaw challenging the detection limits of the trace gas measurement techniques and limiting the dynamic range of the instrument comparison. Occasionally, however, the westerly flow was replaced by thermally driven upslope flow that brought in polluted air masses out of the Denver-Boulder urban corridor from the east. The trace gas signatures of these upslope events are used to characterize the frequency and spatial extent of the specific flow mechanisms. Upslope flow reached regional scale at sunset, providing short instances of the best meteorological conditions for comparing the trace gas measurements at higher concentration levels. The concept of a generally easterly moving layer of regionally polluted air masses applies and agrees well with these observations. Two pollution events on September 28 and 29, 1993, are studied in detail and strongly support this concept. These complex upslope transport mechanisms may have the potential for mixing anthropogenic pollutants into the free troposphere. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. RI Williams, Eric/F-1184-2010; Fehsenfeld, Frederick/I-4876-2013 NR 19 TC 1 Z9 1 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 20 PY 1997 VL 102 IS D5 BP 6199 EP 6213 DI 10.1029/96JD03251 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100030 ER PT J AU Harder, JW Jakoubek, RO Mount, GH AF Harder, JW Jakoubek, RO Mount, GH TI Measurement of tropospheric trace gases by long-path differential absorption spectroscopy during the 1993 OH Photochemistry Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OPTICAL-ABSORPTION; MCMURDO STATION; NO2; COLORADO; ANTARCTICA AB In August and September 1993 a comparative study of tropospheric long-path absorption techniques with in situ methods was performed for both the hydroxyl radical and the other important trace species. Long-path measurements were made over the 10.3 km path between Fritz Peak Observatory and Caribou Mine in the mountains 17 km west of Boulder, Colorado. At Caribou Mine, a 121 element, 1 m(2) retroreflector array folds the optical path to give a total path of 20.6 km. The in situ instruments were located at Idaho Hill 0.5 km northwest of Caribou Mine. The optical design and analysis techniques used to obtain the path-integrated concentrations of O-3, CH2O, SO2, and NO2 will be presented. The spectrograph used in this study is a 1/4 m double, crossed Czerny-Turner that employs a diode array detector allowing the acquisition of 40 nm spectral bands in the near UV and visible spectral regions. This system also utilizes automatic alignment and self-adjusting time integration so the system will acquire data in an unattended mode. The spectral bands selected for this study permit the simultaneous measurement of O-3, NO2, CH2O, and SO2; NO2 and H2O; and NO3 and H2O. The data analysis uses a nonlinear least squares regression procedure to deduce the concentration of each of the species present in the atmosphere and also provides an effective method for removing the influence of scattered solar light for daytime measurements. An estimate of the measurement precision can be found by comparing atmospheric spectra analyzed with two different I-0 spectra; one measured through the atmosphere and the other a direct are lamp spectrum. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Harder, JW (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E-AL7, BOULDER, CO 80303 USA. NR 32 TC 15 Z9 15 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 20 PY 1997 VL 102 IS D5 BP 6215 EP 6226 DI 10.1029/96JD03608 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100031 ER PT J AU Harder, JW Williams, EJ Baumann, K Fehsenfeld, FC AF Harder, JW Williams, EJ Baumann, K Fehsenfeld, FC TI Ground-based comparison of NO2, H2O, and O-3 measured by long-path and in situ techniques during the 1993 tropospheric OH photochemistry experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB One of the major objectives of the 1993 Tropospheric OH Photochemistry Experiment (August 8 to October 4, 1993) was to compare atmospheric measurements of the important trace gas species NO2, O-3, and H2O by in situ techniques and by long-path differential absorption spectroscopy. These compounds were measured over a 20.6 km folded optical path from Fritz Peak Observatory to Caribou Mine where a retroreflector array is located. In situ measurements were made at Idaho Hill, 0.7 km northwest of Caribou Mine and 25 km west of Boulder, Colorado. NO2 was determined at Idaho Hill by photolysis followed by NO chemiluminescence. O-3 and H2O were measured at this site using calibrated commercial instruments. Using fractional differences ([long path - Idaho Hill]/Idaho Hill) as a measure of agreement, overall agreement for ozone and water are +3+/-7% and -4+/-17%, respectively. For NO2 the comparison is complicated by the influence of strong sources and large ambient variability during the measurements. During times of clean westerly flow, fractional differences of +30+/-110% were observed. Further analysis of the data to evaluate these biases show that for mixing ratios greater than 300 pptv (well above the lo detection limit of 30-45 pptv) the two methods differ by no more than 10%, a value well within the combined uncertainties of the measurement techniques. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Harder, JW (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E-AL7, BOULDER, CO 80303 USA. RI Williams, Eric/F-1184-2010; Fehsenfeld, Frederick/I-4876-2013 NR 8 TC 21 Z9 21 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 MAR 20 PY 1997 VL 102 IS D5 BP 6227 EP 6243 DI 10.1029/96JD01729 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100032 ER PT J AU Harder, JW Brault, JW AF Harder, JW Brault, JW TI Atmospheric measurements of water vapor in the 442-nm region SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ABSORPTION-MEASUREMENTS; MCMURDO STATION; NO2; SPECTROSCOPY; ANTARCTICA; SPECTRUM; DATABASE; OXYGEN AB In recent years much interest has been generated in the atmospheric community concerning low resolution water vapor cross sections in the blue spectral region. Proper removal of water absorption from long path tropospheric and zenith sky stratospheric measurements has posed a significant problem for recovery of absorption spectra of low concentration molecular species which overlap the water vapor spectrum. The 7-quanta 4 nu(1)+3 nu(3) and 5 nu(1)+2 nu(3) water vapor overtone bands absorb light near 442.6 nm, and were found to have an integrated band intensity of 4.05 x 10(-24) cm(-1) cm(2) molecule(-1) with a measured accuracy of 4%. This cross section was synthesized from high resolution (0.001 nm or 0.055 cm(-1)) solar spectra taken on the Fourier transform spectrometer at the National Solar Observatory (NSO). This cross section was convolved with the instrument function of a low resolution spectrometer and used to simultaneously measure tropospheric water vapor and nitrogen dioxide over a folded 20.6 km optical path. A comparison of this spectroscopic measurement and a frost point hygrometer located at one end of the path agree to within 4%+/-17% with the spectroscopic measurement generally lower. Some of the observed discrepancy can be explained by the proximity of the hygrometric measurement to local surface sources of water, and by the tendency of the elevated long path measurement to sample drier air coming from aloft. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Harder, JW (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E-AL7, BOULDER, CO 80303 USA. NR 16 TC 29 Z9 31 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 1997 VL 102 IS D5 BP 6245 EP 6252 DI 10.1029/96JD01730 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100033 ER PT J AU Harder, JW Fried, A Sewell, S Henry, B AF Harder, JW Fried, A Sewell, S Henry, B TI Comparison of tunable diode laser and long-path ultraviolet/visible spectroscopic measurements of ambient formaldehyde concentrations during the 1993 OH Photochemistry Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERE AB Two different spectroscopic techniques for measuring atmospheric concentrations of formaldehyde were compared during a 6-week field study in the mountains 17 km west of Boulder, Colorado, in August and September 1993. A long-path ultraviolet/visible (UV/Vis) absorption spectrometer and an IR tunable diode laser absorption spectrometer (TDLAS) were the two instruments employed. The former measured ambient formaldehyde levels over a 10.3 km open path (20.6 km total path) extending between Fritz Peak Observatory and Idaho Hill, while the latter measured in situ levels at the Idaho Hill site. In addition to utilizing different spectral regions, both instruments employed different sampling and calibration approaches. Because of the closer proximity to anthropogenic sources the long-path UV/Vis instrument generally detected higher formaldehyde concentrations than the TDLAS system at all times during the day. Averaged over the entire study for all wind regimes, the former resulted in formaldehyde concentrations 15% higher than the latter. The mean and median formaldehyde concentration measured by both instruments was around 1.5 ppbv and individual 5-min averages varied from a maximum of about 5 ppbv down to levels 0.6 ppbv. However, during periods of strong westerly flow where anthropogenic and meteorological influences are minimized, both techniques were in agreement to within 5%. This regime, which constitutes 19% of the total mutual data set, resulted in a continental background formaldehyde concentration of 0.92 +/- 0.16 ppbv. The present instrument comparison thus bridges the gap in formaldehyde instrument comparison studies between those in the background free troposphere and those in polluted urban regimes. In addition to providing further confidence in both measurement techniques, the present comparison study also provided a valuable data set necessary for advancing our understanding of tropospheric oxidation mechanisms. A set of guidelines for future comparisons of long-path and in situ measurements of formaldehyde at this site are also discussed. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. RP Harder, JW (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E-AL7, BOULDER, CO 80303 USA. NR 22 TC 34 Z9 35 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 20 PY 1997 VL 102 IS D5 BP 6267 EP 6282 DI 10.1029/96JD01731 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100035 ER PT J AU Fried, A McKeen, S Sewell, S Harder, J Henry, B Goldan, P Kuster, W Williams, E Baumann, K Shetter, R Cantrell, C AF Fried, A McKeen, S Sewell, S Harder, J Henry, B Goldan, P Kuster, W Williams, E Baumann, K Shetter, R Cantrell, C TI Photochemistry of formaldehyde during the 1993 Tropospheric OH Photochemistry Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC OXIDATION; ALPHA-PINENE; OZONE BUDGET; BETA-PINENE; ACETALDEHYDE; AIR; HYDROCARBONS; VARIABILITY; PHOTOLYSIS; ABSORPTION AB The present study examines in detail the photochemistry of the important hydrocarbon intermediate HCHO during the 1993 Fritz Peak/Idaho Hill OH Photochemistry Experiment. Measurement-model relationships for HCHO were studied employing a box model with input measurements of hydrocarbons, photolysis frequencies, NOx, and HOx measured at the Idaho Hill sampling site during clean westerly flow. Tunable diode laser absorption and long-path UV-visible absorption spectroscopic techniques provided the high-quality time-resolved ambient HCHO database necessary for this study. For clear sky conditions during clean westerly flow, midday HCHO measurements and model calculations were in agreement to within 12% under various realistic model scenarios. This is significant since it places constraints on the OH concentrations as well as the characteristics of potential missing hydrocarbons necessary to balance measured and modeled OH. Measurement relationships between HCHO and CH3CHO were also investigated; polluted air from the Denver-Boulder front range resulted in the following linear regression: [HCHO] = (0.62 +/- 0.20) ppbv + (1.83 +/- 0.15) CH3CHO. The slope reflects the large if not dominant influence of primary and biogenic emissions, and the intercept reflects the existence of HCHO sources which are not sources of CH3CHO. Clean westerly flow produced a significantly different relationship with no obvious correlation, and this is consistent with smaller biogenic sources of CH3CHO compared with the much larger known biogenic sources of HCHO. C1 NOAA, AERON LAB, BOULDER, CO 80303 USA. RP Fried, A (reprint author), NATL CTR ATMOSPHER RES, DIV ATMOSPHER CHEM, BOX 3000, BOULDER, CO 80307 USA. RI Williams, Eric/F-1184-2010; Kuster, William/E-7421-2010; McKeen, Stuart/H-9516-2013 OI Kuster, William/0000-0002-8788-8588; NR 41 TC 38 Z9 41 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 MAR 20 PY 1997 VL 102 IS D5 BP 6283 EP 6296 DI 10.1029/96JD03249 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100036 ER PT J AU Williams, EJ Roberts, JM Baumann, K Bertman, SB Buhr, S Norton, RB Fehsenfeld, FC AF Williams, EJ Roberts, JM Baumann, K Bertman, SB Buhr, S Norton, RB Fehsenfeld, FC TI Variations in NOy composition at Idaho Hill, Colorado SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ODD-NITROGEN NOY; ORGANIC NITRATES; PEROXYACETYL NITRATE; NITRIC-ACID; NIWOT-RIDGE; PARTICULATE NITRATE; UNITED-STATES; TROPOSPHERE; BUDGET; SITE AB Measurements of NOy and the principal constituent NOy species (NO, NO2, PAN, HNO3, PPN, NO3-) were taken during the fall of 1993 at a high-elevation site in the Colorado mountains west of Boulder. The meteorology provided two principal flow regimes: strong westerly flow, bringing drier and cleaner air over the Continental Divide from the west where emission sources are sparse, and weaker easterly upslope flow which brought moist and more polluted air from the Denver-Boulder urban corridor and perhaps from smaller more local sources such as the mountain town of Nederland. The upslope flow data generally indicate a balance between measured NOy and the separately measured NOy species with NOx, PAN, and HNO3 accounting for over 90%. Under these conditions, NOx was the dominant fraction of NOy, and occasionally fresh emissions were indicated as shown by NOx/NOy close to unity. For downslope flow there was generally a shortfall in the NOy balance where measured NOy was higher than the constituent species by about 20%, on average. Known potential interferences in the measurements do not appear to account for the NOy deficit. Missing NOy correlated directly with NOx/NOy, O-3, and aerosols and inversely with temperature. These relationships suggest the presence of one or more NOy species that were not measured by the individual techniques. C1 UNIV COLORADO, CIRES, BOULDER, CO 80309 USA. RP Williams, EJ (reprint author), NOAA, ERL, AERON LAB, 325 BROADWAY, BOULDER, CO 80303 USA. RI Roberts, James/A-1082-2009; Williams, Eric/F-1184-2010; Fehsenfeld, Frederick/I-4876-2013 OI Roberts, James/0000-0002-8485-8172; NR 28 TC 30 Z9 30 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 MAR 20 PY 1997 VL 102 IS D5 BP 6297 EP 6314 DI 10.1029/96JD03252 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100037 ER PT J AU Goldan, PD Kuster, WC Fehsenfeld, FC AF Goldan, PD Kuster, WC Fehsenfeld, FC TI Nonmethane hydrocarbon measurements during the Tropospheric OH Photochemistry Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AIR MASSES; EMISSION; CHEMISTRY; COLORADO; METHANOL; HYDROXYL; RATIOS; FLUXES AB In the rural troposphere, the nonmethane hydrocarbon compounds (NMHCs) play a significant role in establishing the absolute, as well as, the relative concentration of the odd-hydrogen radicals. In order to provide data which could be used to estimate OH reactive loss rates with hydrocarbons directly, and to broaden our understanding of the production of biogenic NMHCs in and the transport of anthropogenic NMHCs into the Colorado mountains, in situ hydrocarbon measurements were made during the Tropospheric OH Photochemistry Experiment in the fall of 1993. NMHC measurements were made using an automated gas chromatographic system that was capable of quantifying alkanes C-3 (propane) through C-10 (decane), alkenes C-4 (butene) through C-10 (decene), light alcohols from C-1 (methanol) through C-5 (pentanol), light ketones from C-3 (acetone) through C-5 (pentanone), aromatics from C-6 (benzene) through C-9 (trimethylbenzenes), C-10 monoterpenes, and acetaldehyde. During periods of influx of urban air masses, the NMHCs appeared to be the dominant sink for OH radicals. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Goldan, PD (reprint author), NOAA, AERON LAB, 325 BROADWAY, BOULDER, CO 80303 USA. RI Kuster, William/E-7421-2010; Fehsenfeld, Frederick/I-4876-2013 OI Kuster, William/0000-0002-8788-8588; NR 27 TC 28 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 MAR 20 PY 1997 VL 102 IS D5 BP 6315 EP 6324 DI 10.1029/96JD01868 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100038 ER PT J AU Murphy, DM Thomson, DS Kaluzhny, M Marti, JJ Weber, RJ AF Murphy, DM Thomson, DS Kaluzhny, M Marti, JJ Weber, RJ TI Aerosol characteristics at Idaho Hill during the OH Photochemistry Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB This paper supports other measurements at Idaho Hill by describing measurements of the aerosol surface area, volume, and size distribution. The aerosol size distributions at the Idaho Hill site showed nuclei and accumulation modes similar to other clean continental sites. However, there were fewer large aerosols. Principal components analysis verifies that the modes present in the size distribution also had distinct time behavior. The coarse aerosol mode had two components with distinctly different time behavior: aerosols larger than 2 mu m displayed a great deal of shortterm variability not present in smaller aerosols. Accumulation mode aerosols had separate correlations with fresh and aged pollution, whereas smaller aerosols were correlated only with fresh pollution. Aerosols larger than 15 nm showed no diurnal variation in downslope conditions and an afternoon maximum in upslope conditions. Aerosol surface areas were too small to directly affect OH chemistry even if OH or HO2 had fast surface losses. Aerosol volumes indicate that aerosol nitrate is not a likely candidate to balance the NOy shortfall. C1 UNIV MINNESOTA, DEPT MECH ENGN, MINNEAPOLIS, MN 55455 USA. RP Murphy, DM (reprint author), NOAA, AERON LAB, 325 BROADWAY, MAIL CODE R-E-AL6, BOULDER, CO 80303 USA. RI Murphy, Daniel/J-4357-2012 OI Murphy, Daniel/0000-0002-8091-7235 NR 10 TC 12 Z9 12 U1 1 U2 2 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 20 PY 1997 VL 102 IS D5 BP 6325 EP 6330 DI 10.1029/96JD02552 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100039 ER PT J AU Murphy, DM Thomson, DS AF Murphy, DM Thomson, DS TI Chemical composition of single aerosol particles at Idaho Hill: Positive ion measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The chemical compositions of single aerosol particles larger than 0.3 mu m optical diameter were measured at Idaho Hill using a laser ionization mass spectrometer. The mass spectrometer can analyze either positive or negative ions; this paper covers the positive ion results. Potassium, iron, and organics were among the most common positive ions in the spectra of particles at Idaho Hill. Organic ions were the largest contributor to the ion current from accumulation mode particles and were also significant in larger particles. Iron was present mostly in coarse mode particles. Potassium was bimodal, with large amounts of K in coarse mode particles and large amounts in particles near 0.3 mu m in west winds but not in east winds. Boron was observed in a number of particles. A wide variety of metals were also observed including lead, tin, and vanadium. Lead was less common in polluted air. Silver, copper, zinc, nickel, molybdenum, rhenium, and thallium were also observed in a few particles. Ammonium ions and duster ions were more abundant in upslope conditions. Amines seem to be evident in many of the spectra, especially in east winds. Elemental carbon was observed in 2 to 3% of the particles. Almost all of the particles contained some nonvolatile material. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Murphy, DM (reprint author), NOAA, US DEPT COMMERCE, AERON LAB, 325 BROADWAY, MAIL CODE R-E-AL6, BOULDER, CO 80303 USA. RI Murphy, Daniel/J-4357-2012 OI Murphy, Daniel/0000-0002-8091-7235 NR 9 TC 78 Z9 79 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 20 PY 1997 VL 102 IS D5 BP 6341 EP 6352 DI 10.1029/96JD00858 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100041 ER PT J AU Murphy, DM Thomson, DS AF Murphy, DM Thomson, DS TI Chemical composition of single aerosol particles at Idaho Hill: Negative ion measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MICROPROBE MASS ANALYSIS; REAL-TIME; SEA-SALT; SPECTROMETER; SULFATE; SIZE AB The chemical compositions of single aerosol particles larger than 0.3 mu m optical diameter were measured at Idaho Hill using a laser ionization mass spectrometer. The mass spectrometer can analyze either positive or negative ions; this paper covers the negative ion results. Sulfate, nitrate, organics, O-, and OH- were the most common peaks observed in the negative ion spectra. Other species identified in the negative ion spectra include silicon, chlorine, iodine, organic acids, and elemental carbon. Neither external nor internal mixing completely describes the particles: most of the particles were in various classes that were distinctly different from each other. All air masses had more than one class of particle present. However, most of the particle classes were in themselves mixtures. Sulfate was the most common negative ion in smaller particles whereas nitrate and complicated mixtures were more common in particles larger than about 0.7 mu m. However, nearly all types of particles were observed in all size ranges and wind conditions. Aerosol chemistry was not well correlated with gas phase chemistry. Certain combinations, such as nitrate and silicon, were frequently observed together in single particles. Sulfate and chlorine did not coexist in the same particles, nor did silicon and elemental carbon. Small amounts of organics were present in most particles. Sulfate and nitrate were usually, but not always, in different particles. The nitrate/sulfate ratio estimated with the mass spectrometer data correlated well with filter measurements. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Murphy, DM (reprint author), NOAA, US DEPT COMMERCE, AERON LAB, 325 BROADWAY, MAIL CODE R-E-AL6, BOULDER, CO 80303 USA. RI Murphy, Daniel/J-4357-2012 OI Murphy, Daniel/0000-0002-8091-7235 NR 22 TC 93 Z9 93 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 MAR 20 PY 1997 VL 102 IS D5 BP 6353 EP 6368 DI 10.1029/96JD00859 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100042 ER PT J AU Cantrell, CA Shetter, RE Calvert, JG Eisele, FL Williams, E Baumann, K Brune, WH Stevens, PS Mather, JH AF Cantrell, CA Shetter, RE Calvert, JG Eisele, FL Williams, E Baumann, K Brune, WH Stevens, PS Mather, JH TI Peroxy radicals from photostationary state deviations and steady state calculations during the Tropospheric OH Photochemistry Experiment at Idaho Hill, Colorado, 1993 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLEAN-AIR; SITES; ROSE AB Concentrations of peroxy radicals and a number of other trace gases were measured during the Tropospheric OH Photochemistry Experiment in August and September, 1993. The trace gas concentrations were used to derive two estimates of peroxy radical levels: deviations from the photostationary state, and theoretical calculations with the assumption of steady state radical concentrations. As in many previous studies, the photostationary state method yielded midday peroxy radical levels about twice those measured. Calculations were performed to assess the expected uncertainty in the photostationary state derived peroxy radical concentrations from the uncertainty of the input parameters. The agreement between measurements and steady state determinations was better than the photostationary state estimates, with the measurements slightly higher on average. Radical formation and destruction rates for clear sky conditions with low and high NOx were derived from the steady state calculations and the results demonstrate the processes that control peroxy radical levels in clean and polluted continental atmospheres. C1 NOAA, AERON LAB, BOULDER, CO 80303 USA. PENN STATE UNIV, DEPT METEOROL, UNIVERSITY PK, PA 16802 USA. RP Cantrell, CA (reprint author), NATL CTR ATMOSPHER RES, POB 3000, BOULDER, CO 80307 USA. RI Williams, Eric/F-1184-2010 NR 27 TC 52 Z9 52 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 20 PY 1997 VL 102 IS D5 BP 6369 EP 6378 DI 10.1029/96JD01703 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100043 ER PT J AU Stevens, PS Mather, JH Brune, WH Eisele, F Tanner, D Jefferson, A Cantrell, C Shetter, R Sewall, S Fried, A Henry, B Williams, E Baumann, K Goldan, P Kuster, W AF Stevens, PS Mather, JH Brune, WH Eisele, F Tanner, D Jefferson, A Cantrell, C Shetter, R Sewall, S Fried, A Henry, B Williams, E Baumann, K Goldan, P Kuster, W TI HO2/OH and RO(2)/HO2 ratios during the Tropospheric OH Photochemistry Experiment: Measurement and theory SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PEROXY-RADICALS; PHOTOSTATIONARY STATE; NATURAL HYDROCARBONS; RATE CONSTANTS; GAS-PHASE; KINETICS; MECHANISM; CHEMISTRY; NO; TEMPERATURE AB Ambient concentrations of the hydroxyl (OH), hydroperoxyl (HO2), and total peroxy (Sigma RO(2)) radicals were measured as part of the Tropospheric OH Photochemistry Experiment at Idaho Hill, Colorado, during August and September of 1993. OH radicals were measured using ion-assisted mass spectroscopy and low-pressure laser-induced fluorescence (LIF) detection techniques. HO2 was measured using; chemical conversion and LIF detection of OH. Sigma RO(2) radicals were measured using a chemical amplifier technique, The simultaneous measurements of these key species provide an opportunity to test our present understanding of the fast photochemistry of the troposphere, Measured HO2/OH ratios were typically between 15 and 80, and agreed well with predictions under conditions where NO mixing ratios were greater than 100 pptv, However, under clean conditions the measured ratio was a factor of 3-4 lower than predicted. The RO(2)/HO2 ratio was typically a factor of 4-15 larger than predicted by present theories of tropospheric chemistry, A steady state model was used in an attempt to analyze the discrepancies between the measured HO2/OH and RO(2)/HO2 ratios with present theories of hydrocarbon oxidation in the troposphere. C1 PENN STATE UNIV, DEPT METEOROL, UNIVERSITY PK, PA 16802 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. RI Williams, Eric/F-1184-2010; Kuster, William/E-7421-2010; Jefferson, Anne/K-4793-2012 OI Kuster, William/0000-0002-8788-8588; NR 38 TC 65 Z9 67 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 MAR 20 PY 1997 VL 102 IS D5 BP 6379 EP 6391 DI 10.1029/96JD01704 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100044 ER PT J AU Mount, GH Brault, JW Johnston, PV Marovich, E Jakoubek, RO Volpe, CJ Harder, J Olson, J AF Mount, GH Brault, JW Johnston, PV Marovich, E Jakoubek, RO Volpe, CJ Harder, J Olson, J TI Measurement of tropospheric OH by long-path laser absorption at Fritz Peak Observatory, Colorado, during the OH Photochemistry Experiment, Fall 1993 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERE; CHEMISTRY AB The determination of the concentration of hydroxyl (OH) in the Earth's troposphere is of fundamental importance to an understanding of the chemistry of the lower atmosphere. This paper describes the results from the laser long-path spectroscopic OH experiment used in the Tropospheric OH Photochemistry Experiment (TOHPE) held at Fritz Peak, Colorado, in fall 1993. A primary goal of TOHPE was to compare the OH concentrations measured using a variety of different techniques: a long-path spectroscopic instrument [Mount, 1992], an in situ ion-assisted chemical conversion instrument (Eisele and Tanner, 1991, 1993), a laser resonance fluorescence instrument [Stevens et al., 1994), and a liquid scrubber instrument (X. Chen and K. Mopper, unpublished data,; 1996), all with sensitivities at or below 1 x 10(6) molecules cm(-3). In addition to the OH measurements, a nearly complete suite of trace gas species that affect the OH concentration were measured simultaneously, using both in situ and/or long-path techniques, to provide the information necessary to understand the OH variation and concentration differences observed. Measurements of OH, NO2, CH2O, SO2, H2O, and O-3 were made using long-path spectroscopic absorption of white light or laser light and OH, NO, NO2, NOy, O-3, CO, SO2, CH2O, j(O-3), j(NO2), RO(2)/HO2, HO2, H2O, SO2, PAN, PPN, HNO3, and aerosols (size and composition) and ozone and nitrogen dioxide j-values were measured using in situ instruments. Meteorological parameters at each end of the long path and at the Idaho Hill in situ site were also measured. The comparison of the long-path and in situ species from this set of complementary measurements provides an effective way of interpreting air masses over the long path with those at the in situ site; this is a critical issue since the long-path spectroscopic OH determinations provide a nonchemical and well-calibrated measurement of OH which must be compared in a meaningful manner with the in situ determinations. Over the period of the TOHPE experiment, OH concentrations were typically low during periods of clean and clear airflow, averaging about 4 x 10(6) molecules cm(-3) at noon. In contrast, during the well-defined pollution episodes which occurred during the campaign, OH concentrations rose as high as 15 x 10(6) molecules cm(-3). C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. NIWA, LAUDER, CENTRAL OTAGO, NEW ZEALAND. RP Mount, GH (reprint author), NOAA, AERON LAB, ENVIRONM RES LABS, 325 BROADWAY, BOULDER, CO 80303 USA. NR 22 TC 29 Z9 29 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 20 PY 1997 VL 102 IS D5 BP 6393 EP 6413 DI 10.1029/96JD00401 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100045 ER PT J AU Mount, GH Eisele, FL Tanner, DJ Brault, JW Johnston, PV Harder, JW Williams, EJ Fried, A Shetter, R AF Mount, GH Eisele, FL Tanner, DJ Brault, JW Johnston, PV Harder, JW Williams, EJ Fried, A Shetter, R TI An intercomparison of spectroscopic laser long-path and ion-assisted in situ measurements of hydroxyl concentrations during the Tropospheric OH Photochemistry Experiment, fall 1993 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ABSORPTION; COLORADO AB Hydroxyl plays a central role in the chemistry of the troposphere. Since the importance of OH was first recognized in the early 1970s, many experiments have attempted to measure OH, but very few have been successful, and much controversy has surrounded the measurements made [Crosley, this issue]. Thus, intercomparison of OH measurements is a requirement for community acceptance of derived OH concentrations, and accurate measurements of OH are essential to provide robust modeling of tropospheric chemistry since models typically allow OH concentrations to be determined within the model for lack of measurements. The Tropospheric OH Photochemistry Experiment held in the Colorado Rocky Mountains in fall 1993 brought together four instruments that to measure OH. In order to make a proper comparison, a number of other trace species and relevant jvalues were measured simultaneously with hydroxyl to provide a photochemical understanding of the measurements and an understanding of the airflow in the mountainous region in which this work was conducted. This region provided opportunities to measure both clean and polluted air over a wide dynamic range of species that affect the OH concentration. The measurements extended over a long enough period of time that a large quantity of data were collected under a variety of atmospheric conditions, thus allowing for a meaningful comparison of techniques. The long-path spectroscopic laser system and the in situ selected ion chemical ionization mass spectrometry system determined OH concentrations for 4 weeks simultaneously. Generally, the derived concentrations from the two instruments agreed within the 2 sigma error bars over half the observation time. One quarter of the time, OH differences could be explained by different air masses between the long path and in situ site which contained different concentrations of trace species that affect OH abundance. Approximately one quarter of the data disagreed outside the observational errors with no obvious explanation. The long-path experiment typically gave concentrations about 20% higher than the ion-assisted experiment. This could be caused by inaccuracies in the absolute calibrations of the two instruments, or by trace species variations along the long path that differed from those at the in situ site, Generally, agreement between ion-assisted and long-path OH measurements was good, showing that measurements of hydroxyl in the troposphere can be performed with good accuracy on a routine basis. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. NATL INST WATER & ATMOSPHERES, LAUDER, CENTRAL OTAGO, NEW ZEALAND. GEORGIA INST TECHNOL, GEORGIA TECH RES INST, ELECTROOPT ENVIRONM & MAT LAB, ATLANTA, GA 30332 USA. RP Mount, GH (reprint author), NOAA, AERON LAB, ENVIRONM RES LABS, 325 BROADWAY, BOULDER, CO 80303 USA. RI Williams, Eric/F-1184-2010 NR 6 TC 23 Z9 23 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 20 PY 1997 VL 102 IS D5 BP 6437 EP 6455 DI 10.1029/96JD02342 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100048 ER PT J AU Eisele, FL Mount, GH Tanner, D Jefferson, A Shetter, R Harder, JW Williams, EJ AF Eisele, FL Mount, GH Tanner, D Jefferson, A Shetter, R Harder, JW Williams, EJ TI Understanding the production and interconversion of the hydroxyl radical during the Tropospheric OH Photochemistry Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The hydroxyl radical plays a critical role in the chemistry of the lower atmosphere. Understanding its production, interconversion, and sinks is central to modeling and predicting the chemistry of the troposphere. The OH measurements made during the 1993 Tropospheric OH Photochemistry Experiment provide a detailed look at these mechanisms since NOx, j(O-3), RO(2), HO2, nonmethane hydrocarbons (NMHC), and many other relevant species were measured simultaneously. The relationship of OH to NOx and to primary production is extensively examined. Close agreement with theory is shown in the NOx/OH relation with OH concentrations increasing with increasing NO to a maximum at 1-2 ppbv due to conversion of HO2 to OH, and then OH decreasing with further increasing NOx due to conversion of NO2 to HNO3. Close correlations of OH concentrations with primary production (water, ozone, j(O-3)) are also shown both on average and on rapid timescales. C1 GEORGIA INST TECHNOL, GEORGIA TECH RES INST, ELECTOOPT ENVIRONM & MAT LAB, ATLANTA, GA 30332 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Eisele, FL (reprint author), NATL CTR ATMOSPHER RES, DIV ATMOSPHER CHEM, POB 3000, BOULDER, CO 80307 USA. RI Williams, Eric/F-1184-2010; Jefferson, Anne/K-4793-2012 NR 1 TC 33 Z9 33 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 MAR 20 PY 1997 VL 102 IS D5 BP 6457 EP 6465 DI 10.1029/96JD02207 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100049 ER PT J AU McKeen, SA Mount, G Eisele, F Williams, E Harder, J Goldan, P Kuster, W Liu, SC Baumann, K Tanner, D Fried, A Sewell, S Cantrell, C Shetter, R AF McKeen, SA Mount, G Eisele, F Williams, E Harder, J Goldan, P Kuster, W Liu, SC Baumann, K Tanner, D Fried, A Sewell, S Cantrell, C Shetter, R TI Photochemical modeling of hydroxyl and its relationship to other species during the Tropospheric OH Photochemistry Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID METHYL VINYL KETONE; GAS-PHASE REACTIONS; CHEMICAL MECHANISM; UNITED-STATES; NIWOT-RIDGE; PHOTOSTATIONARY STATE; NATURAL HYDROCARBONS; ORGANIC-COMPOUNDS; PEROXY-RADICALS; ALPHA-PINENE AB Because of the extremely short photochemical lifetime of tropospheric OH, comparisons between observation and model calculations should be an effective test of our understanding of the photochemical processes controlling the concentration of OH, the primary oxidant in the atmosphere. However, unambiguous estimates of calculated OH require sufficiently accurate and complete measurements of the key species and physical variables that determine OH concentrations. The Tropospheric OH Photochemistry Experiment (TOHPE) provides an extremely complete set of measurements, sometimes from multiple independent experimental platforms, that allows such a test to be conducted. When the calculations explicitly use observed NO, NO2, hydrocarbons, and formaldehyde, the photochemical model consistently overpredicts in situ observed OH by similar to 50% for the relatively clean conditions predominantly encountered at Idaho Hill. The model bias is much higher when only CH4-CO chemistry is assumed, or NO is calculated from the steady state assumption. For the most polluted conditions encountered during the campaign, the model results and observations show better agreement. Although the comparison between calculated and observed OH can be considered reasonably good given the +/-30% uncertainties of the OH instruments and various uncertainties in the model, the consistent bias suggests a fundamental difference between theoretical expectations and the measurements. Several explanations for this discrepancy are possible, including errors in the measurements, unidentified hydrocarbons, losses of HOx to aerosols and the Earth's surface, and unexpected peroxy radical chemistry. Assuming a single unidentified type of hydrocarbon is responsible, the amount of additional hydrocarbon needed to reduce theoretical OH to observed levels is a factor of 2 to 3 greater than the OH-reactivity-weighted hydrocarbon content measured at the site. Constraints can be placed on the production and yield of various radicals formed in the oxidation sequence by considering the observed levels of certain key oxidation products such as formaldehyde and acetaldehyde. The model results imply that, under midday clean westerly flow conditions, formaldehyde levels are fairly consistent with the OH and hydrocarbon observations, but observed acetaldehyde levels are a factor of 4 larger than what is expected and also imply a biogenic source. Levels of methacrolein and methylvinylketone are much lower than expected from steady state isoprene chemistry, which implies important removal mechanisms or missing information regarding the kinetics of isoprene oxidation within the model. In a prognostic model application, additional hydrocarbons are added to the model in order to force calculated OH to observed levels. Although the products and oxidation steps related to pinenes and other biogenic hydrocarbons are somewhat uncertain, the addition of a species with an oxidation mechanism similar to that expected from C-10 pinenes would be consistent with the complete set of observations, as opposed to naturally emitted isoprene or any of the anthropogenic hydrocarbons examined in the model. Further constraints on the abundance of peroxy radicals are necessary in order to fill the gaps in our understanding of OH photochemistry for the clean continental conditions typical of Idaho Hill. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. NATL CTR ATMOSPHER RES, BOULDER, CO 80303 USA. RP McKeen, SA (reprint author), NOAA, AERON LAB, R-E-AL4, 325 BROADWAY, BOULDER, CO 80303 USA. RI Williams, Eric/F-1184-2010; Kuster, William/E-7421-2010; McKeen, Stuart/H-9516-2013 OI Kuster, William/0000-0002-8788-8588; NR 49 TC 112 Z9 115 U1 2 U2 25 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 1997 VL 102 IS D5 BP 6467 EP 6493 DI 10.1029/96JD03322 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ021 UT WOS:A1997WQ02100050 ER PT J AU Xu, LH Andrews, AM Cavanagh, RR Fraser, GT Irikura, KK Lovas, FJ Grabow, JU Stahl, W Crawford, MK Smalley, RJ AF Xu, LH Andrews, AM Cavanagh, RR Fraser, GT Irikura, KK Lovas, FJ Grabow, JU Stahl, W Crawford, MK Smalley, RJ TI Rotational and vibrational spectroscopy and ideal gas heat capacity of HFC 134a (CF3CFH2) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID AB-INITIO CALCULATIONS; MICROWAVE-SPECTRUM; INTERNAL-ROTATION; MOLECULAR-BEAM; FREQUENCIES; HFC-134A; REFRIGERANTS; SPECTROMETER; COMPLEXES; BARRIERS AB The hydrofluorocarbon HFC 134a (CF3CFH2) is the primary replacement for the chlorofluorocarbon CFC 12 (CF2Cl2) in numerous applications, including automobile air conditioning and home and commercial refrigeration. Here we describe a comprehensive spectroscopic study of this molecule. Precise microwave frequencies and molecular constants have been obtained for the vibrational ground state with a pulsed-molecular-beam Fourier-transform microwave spectrometer. New isotopic ground-state microwave measurements have also been made to improve the ground-state structural determination. Infrared and Raman spectra have been obtained, and all 18 vibrations have been observed and assigned. A high-resolution (3 MHz) microwave-sideband CO2 laser and an electric-resonance optothermal spectrometer have been used to observe the molecular-beam infrared spectrum in the vicinity of the low-resolution gas-phase feature at 975 cm-l assigned here and in some of the earlier studies as the v(15), A ''-symmetry, CH2 rock. Two nearly equal-intensity c-type bands are observed under high resolution with origins at 974.35 and 974.87 cm(-1) The presence of two vibrational bands of A '' symmetry is attributed to strong anharmonic mixing of the v(15) vibration with a nearby combination vibration. On the basis of our low-resolution infrared measurements, we identify the perturbing state as the 3v(18) + v(8) combination level. Finally, the experimental results are used to calculate the vibrational contribution to the heat capacity and are compared with the results of earlier experimental and theoretical work, including our own electronic-structure calculations using an HF/6-31G* basis set. C1 CHRISTIAN ALBRECHTS UNIV KIEL, INST PHYS CHEM, D-24098 KIEL, GERMANY. NATL INST STAND & TECHNOL, OPT TECHNOL DIV, SURFACE & MICROANAL SCI DIV, GAITHERSBURG, MD 20899 USA. NATL INST STAND & TECHNOL, PHYS & CHEM PROPERTIES DIV, GAITHERSBURG, MD 20899 USA. DUPONT CO INC, CENT RES & DEV, WILMINGTON, DE 19880 USA. RI Irikura, Karl/A-4266-2009; Xu, Li-Hong/J-5095-2015 OI Irikura, Karl/0000-0001-7515-6761; NR 47 TC 22 Z9 22 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 20 PY 1997 VL 101 IS 12 BP 2288 EP 2297 DI 10.1021/jp9640383 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WP414 UT WOS:A1997WP41400012 ER PT J AU Imamura, T Rudich, Y Talukdar, RK Fox, RW Ravishankara, AR AF Imamura, T Rudich, Y Talukdar, RK Fox, RW Ravishankara, AR TI Uptake of NO3 on water solutions: Rate coefficients for reactions of NO3 with cloud water constituents SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID RATE CONSTANTS; AQUEOUS-SOLUTION; NIGHTTIME CHEMISTRY; PHASE REACTIONS; KINETICS; ATMOSPHERE; DROPLETS; RADICALS AB The reactive uptake coefficients, gamma, of NO3 onto aqueous solutions containing ions X(-) = HSO3-, SO32-, HCOO-, CH3COO-, and OH- were measured at 273 +/- 1 K using a wetted-wall flow tube reactor. The values of (HD)-D-2/k (H = Henry's law coefficient, D-/ = diffusion coefficient in the liquid phase, and k = second-order rate coefficient for the liquid phase reactions of NO3 with X(-)) for the reactive uptake of NO3 were determined by measuring gamma as a function of liquid phase reactant concentration. The linear correlation between the measured rate coefficients and those for corresponding SO4- reactions, and the dependence of the measured rate coefficients on the redox potential of the X/X(-) pair suggest that the NO3 + X(-) reactions proceed by electron transfer. The atmospheric implications of these findings are briefly discussed. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80303. NOAA,AERON LAB,BOULDER,CO 80303. RI Rudich, Yinon/K-1498-2012; TALUKDAR, RANAJIT/G-4530-2013; Ravishankara, Akkihebbal/A-2914-2011 OI TALUKDAR, RANAJIT/0000-0001-6017-8431; NR 36 TC 19 Z9 19 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 20 PY 1997 VL 101 IS 12 BP 2316 EP 2322 DI 10.1021/jp962787e PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WP414 UT WOS:A1997WP41400016 ER PT J AU Vierheller, TR Foster, MD Schmidt, A Mathauer, K Knoll, W Wegner, G Statija, S Majkrzak, CF AF Vierheller, TR Foster, MD Schmidt, A Mathauer, K Knoll, W Wegner, G Statija, S Majkrzak, CF TI Structure and stability of two-component Langmuir-Blodgett multilayers containing cadmium arachidate and polyglutamate determined by reflectivity SO LANGMUIR LA English DT Article ID X-RAY REFLECTOMETRY; FILMS; DIFFUSION; NEUTRON AB Interlayer diffusion and interdigitation in Langmuir-Blodgett multilayers containing asymmetric interfaces between cadmium arachidate (CdA) and an octadecyl-substituted polyglutamate (PG) were studied using neutron reflectometry and X-ray reflectometry. It was found that the structure of the two-component CdA/PG multilayers is less stable to annealing than is the structure of multilayers containing only CdA or only PG. The PG side chains and CdA tails at adjoining layers appear to interdigitate significantly in unannealed multilayers, and this interdigitation becomes more mal ked after annealing. C1 UNIV AKRON,INST POLYMER SCI,AKRON,OH 44325. MAX PLANCK INST POLYMER RES,D-55021 MAINZ 1,GERMANY. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. INST PHYS & CHEM RES,FRONTIER RES PROGRAM,WAKO,SAITAMA,JAPAN. NR 19 TC 5 Z9 5 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAR 19 PY 1997 VL 13 IS 6 BP 1712 EP 1717 DI 10.1021/la961002t PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA WP366 UT WOS:A1997WP36600054 ER PT J AU VanPoolen, LJ Holcomb, CD Niesen, VG AF VanPoolen, LJ Holcomb, CD Niesen, VG TI Critical temperature and density from liquid-vapor coexistence data: Application to refrigerants R32, R124, and R152a SO FLUID PHASE EQUILIBRIA LA English DT Article ID CRITICAL PARAMETERS; REFRACTIVE-INDEX; SURFACE-TENSION; PRESSURES AB Liquid-vapor coexisting density and temperature data within 3 to 20 K of the critical point at approximately 1 K intervals are used to obtain the critical temperature (T-c) and the critical density (rho(c)) of the refrigerants R32, R124, and R152a. The difference between the saturated liquid density and the saturated vapor density is used to obtain T-c which is, in turn, used in an equation for the rectilinear diameter to obtain rho(c). For the determination of T-c, coexisting densities and temperature are allowed to vary as normally distributed variables about a mean, the reported experimental value, with a standard deviation equal to one-third the reported experimental uncertainty. For the determination of rho(c),T-c is similarly allowed to vary based on its previously determined value and uncertainty. Equally probable data subsets are chosen randomly from the complete data set. Consistent results for T-c and rho(c), obtained as averages, and their uncertainties expressed at the 2 sigma level based on deviations from these averages, are achieved when the data selection-data fitting procedure is repeated two to three hundred times. The critical values obtained agree with those in the literature within the estimated uncertainties. This method yields critical properties consistent with experimental coexisting properties using data removed from the critical point and can complement various methods of determining T-c and rho(c) that include the direct observation of the critical point. (C) 1997 Elsevier Science B.V. C1 NATL INST STAND & TECHNOL,DIV THERMOPHYS,CHEM SCI & TECHNOL LAB,BOULDER,CO 80303. CALVIN COLL,DEPT ENGN,GRAND RAPIDS,MI 49546. CONOCO INC,PONCA CITY,OK 74603. NR 18 TC 11 Z9 11 U1 0 U2 7 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 MAR 15 PY 1997 VL 129 IS 1-2 BP 105 EP 111 DI 10.1016/S0378-3812(96)03171-8 PG 7 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA WY212 UT WOS:A1997WY21200009 ER PT J AU Angell, JK AF Angell, JK TI Estimated impact of Agung, El Chichon and Pinatubo volcanic eruptions on global and regional total ozone after adjustment for the Quasi-Biennial Oscillation (QBO) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NINO-SOUTHERN OSCILLATION; STRATOSPHERIC OZONE; MT-PINATUBO; HETEROGENEOUS CHEMISTRY; ATMOSPHERIC OZONE; MOUNT-PINATUBO; AEROSOL; TEMPERATURE; DEPLETION AB Dobson total-ozone data are used to compare the impact on global and regional total ozone of Agung, El Chichon and Pinatubo volcanic eruptions taking into account the quasi-biennial oscillation (QBO). This is done by comparing the total-ozone variation following the 3 eruptions with the average quasi-biennial variation in total ozone obtained by applying the superposed epoch method to the 13 QBO cycles between 1958 and 1995 which do not include these 3 eruptions. Confidence estimates are based on the 2-standard-deviation value of the 13 comparisons. The largest volcanic impact on total ozone is in the European region, with significant (at the 5% level) total-ozone decreases of about 5% following Agung and El Chichon, and 8% following Pinatubo. The decreases in the north polar zone, Russia, North America and Asia are 5-6% following Pinatubo and 2-3% following El Chichon. In the tropics the ozone decrease is less than 2% following all 3 eruptions, and there is little consistent impact on south temperate or south polar total ozone. Comparisons are made between these findings and those obtained by others using satellite data. RP Angell, JK (reprint author), NOAA,AIR RESOURCES LAB,1315 EAST WEST HIGHWAY,SILVER SPRING,MD 20910, USA. NR 43 TC 33 Z9 33 U1 2 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 15 PY 1997 VL 24 IS 6 BP 647 EP 650 DI 10.1029/97GL00544 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WN972 UT WOS:A1997WN97200007 ER PT J AU Ralph, FM Neiman, PJ Levinson, D AF Ralph, FM Neiman, PJ Levinson, D TI Lidar observations of a breaking mountain wave associated with extreme turbulence SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MOMENTUM FLUX; GRAVITY-WAVE; AIRCRAFT MEASUREMENTS; DOWNSLOPE WINDSTORMS; GENERAL-CIRCULATION; DRAG; EVOLUTION; SIMULATIONS; STABILITY; EVENT AB Observations from a Doppler lidar, which are enhanced by stratospheric aerosols from Mount Pinatubo's eruption, provide unique measurements of mountain waves over the Rocky Mountains, including nearly instantaneous observations of wave breaking in the lower stratosphere. The wave breaking is revealed by a flow-reversal aloft that marks a localized critical layer created when the wave amplitude was great enough to cause overturning. The altitude, spatial scale, and duration of this wave-induced critical layer are documented. The mountain waves led to turbulence affecting commercial aircraft, including one accident in which a cargo jet lost an engine and part of a wing in extreme turbulence at the same time the lidar was making observations nearby. Although earlier observations of mountain-wave drag assumed wave stationarity over 3-5 h, significant changes over less than 2 h are documented here. Such nonstationarity could contribute to discrepancies remaining between observations and simulations of mountain-wave drag. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. RP Ralph, FM (reprint author), NOAA,ENVIRONM TECHNOL LAB,MAIL CODE R-E-ET7,325 BROADWAY,BOULDER,CO 80303, USA. NR 36 TC 24 Z9 24 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 15 PY 1997 VL 24 IS 6 BP 663 EP 666 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WN972 UT WOS:A1997WN97200011 ER PT J AU Ramaswamy, V Chen, CT AF Ramaswamy, V Chen, CT TI Climate forcing-response relationships for greenhouse and shortwave radiative perturbations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GENERAL-CIRCULATION MODEL; PARAMETERIZATION; SENSITIVITY; AEROSOLS; CLOUDS; GASES; CO2 AB The earth's climate system is subject to radiative forcings caused by perturbations in the infrared 'greenhouse' effect and absorbed solar energy. The forcings can be classified as being global in extent (e.g., increase of CO2) or spatially confined to the northern hemisphere midlatitudes (e.g., anthropogenic sulfate aerosols). Of central importance to climate change assessments are the characteristics of the global and latitudinal changes, and the forcing-response relationships for different kinds of perturbations. Using a general circulation climate model with fixed cloud distributions and microphysical properties, we analyze the equilibrium climate responses to different perturbations representing global and spatially localized radiative forcings. The total climate feedback in the various experiments does not differ significantly, and the global-mean climate sensitivity (ratio of the equilibrium global-mean surface temperature change to the global-mean imposed radiative forcing) behaves in a near-invariant manner for both global and spatially confined forcings. However, relative to the global perturbation cases, forcings confined to the northern hemisphere midlatitudes exhibit a steepening of the meridional gradient of the temperature response in that hemisphere. C1 NATL TAIWAN NORMAL UNIV,DEPT EARTH SCI,TAIPEI,TAIWAN. RP Ramaswamy, V (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,POB 308,PRINCETON,NJ 08542, USA. NR 21 TC 11 Z9 11 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 15 PY 1997 VL 24 IS 6 BP 667 EP 670 DI 10.1029/97GL00253 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WN972 UT WOS:A1997WN97200012 ER PT J AU Geller, LS Elkins, JW Lobert, JM Clarke, AD Hurst, DF Butler, JH Myers, RC AF Geller, LS Elkins, JW Lobert, JM Clarke, AD Hurst, DF Butler, JH Myers, RC TI Tropospheric SF6: Observed latitudinal distribution and trends, derived emissions and interhemispheric exchange time SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GROWTH-RATES; DECREASE AB Sulfur hexafluoride (SF6), an anthropogenically produced compound that is a potent greenhouse gas, had been measured in a number of NOAA CMDL air sampling programs. These include high resolution latitudinal profiles over the Atlantic and Pacific oceans, weekly flask samples from seven remote, globally distributed sites, hourly in situ measurements in rural North Carolina, and a series of archived air samples from Niwot Ridge, Colorado. The observed increase in atmospheric mixing ratio is consistent with an overall quadratic growth rate, at 6.9 +/- 0.2% yr(-1) (0.24 +/- 0.01 ppt yr(-1)) for early 1996. From these data we derive an early 1996 emission rate of 5.9 +/- 0.2 Gg SF6 yr(-1) and an interhemispheric exchange time of 1.3 +/- 0.1 years. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Geller, LS (reprint author), NOAA,CLIMATE MONITORING & DIAGNOST LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Hurst, Dale/D-1554-2016 OI Hurst, Dale/0000-0002-6315-2322 NR 15 TC 114 Z9 118 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 15 PY 1997 VL 24 IS 6 BP 675 EP 678 DI 10.1029/97GL00523 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WN972 UT WOS:A1997WN97200014 ER PT J AU Kranbuehl, DE Verdier, PH AF Kranbuehl, DE Verdier, PH TI Separating connectivity and expansion effects in polymer single chain dynamics SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CUBIC LATTICE MODELS; VARIABLE EXCLUDED-VOLUME; BEAD MOVEMENT RULES; MONTE-CARLO METHOD; COORDINATION-NUMBER; COMPUTER-SIMULATION; MULTICHAIN SYSTEMS; RELAXATION; TIME; DIMENSIONS AB The effects of chain volume and connectivity upon the motions of flexible polymers in dilute solution have been studied by computer simulation of simple off-lattice bead-flip models of from 9 to 99 beads. Long internal relaxation times are given for free-draining chains with bead diameters from zero to 0.93 times the stick lengths. Moves are forbidden which would result either in bead overlap (excluded volume) or in one stick passing through another (chain connectivity). In the extreme case of zero bead diameter, where there is no expansion of the chains by excluded volume, the long relaxation time varies as about the 2.1 power of chain length, as opposed to the 2.0 power for similar chains without connectivity constraints. As bead diameter is increased until it equals stick length, the exponent increases to the value of 2.48 established by previous work. Over the range of bead diameters employed, the chain-length dependence of long relaxation times and translational diffusion constants can be described by the sum of two terms, the first due to chain swelling by excluded volume and consistent with the predictions of scaling theory, the second due only to chain connectivity. (C) 1997 American Institute of Physics. C1 NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. RP Kranbuehl, DE (reprint author), COLL WILLIAM & MARY,DEPT CHEM,WILLIAMSBURG,VA 23187, USA. NR 62 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 15 PY 1997 VL 106 IS 11 BP 4788 EP 4796 DI 10.1063/1.473477 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WM910 UT WOS:A1997WM91000044 ER PT J AU Davis, RF Moore, CC Zaneveld, JRV Napp, JM AF Davis, RF Moore, CC Zaneveld, JRV Napp, JM TI Reducing the effects of fouling on chlorophyll estimates derived from long-term deployments of optical instruments SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID BIOOPTICAL PROPERTIES; PHYTOPLANKTON GROWTH; UPPER OCEAN; BERING SEA; TEMPERATURE; ABSORPTION; SPECTRUM; SHELF AB Two methods to alleviate the problem of fouling of moored flow tube optical instruments are presented. A chemical method diffuses a concentrated solution of bromine into the flow tube between sampling periods, creating a toxic environment for microorganisms. An optical method removes a baseline value from the red peak of chlorophyll a. Three spectral absorption meters equipped with the chemical system were deployed in the southeastern Bering Sea from March to September 1993. For a 40-m instrument the system prevented biofouling for the entire deployment, while an 11-m instrument was free of contamination for approximately 3.5 months. Reasonable estimates of in situ chlorophyll a were obtained from all three instruments by the subtraction of the baseline. C1 OREGON STATE UNIV,COLL OCEAN & ATMOSPHER SCI,CORVALLIS,OR 97331. WESTERN ENVIRONM TECHNOL LABS INC,PHILOMATH,OR. NOAA,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115. NR 18 TC 30 Z9 30 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 15 PY 1997 VL 102 IS C3 BP 5851 EP 5855 DI 10.1029/96JC02430 PG 5 WC Oceanography SC Oceanography GA WN409 UT WOS:A1997WN40900023 ER PT J AU Bender, MA AF Bender, MA TI The effect of relative flow on the asymmetric structure in the interior of hurricanes SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID TROPICAL CYCLONE MOTION; KINEMATIC STRUCTURE; VORTEX ASYMMETRIES; BAROTROPIC MODEL; INNER CORE; EVOLUTION; NORBERT; SCHEME AB Asymmetric structure of tropical cyclones simulated by the Geophysical Fluid Dynamics Laboratory high-resolution triply nested movable-mesh hurricane model was analyzed. Emphasis was placed on the quasi-steady component of the asymmetric structure in the region of the eyewall. It was found that the asymmetry was primarily caused by the relative wind, that is, the flow entering and leaving the storm region relative to the moving storm. A set of idealized numerical experiments was first performed both with a constant and a variable Coriolis parameter (f) and the addition of basic flows that were either constant or sheared with height. Analysis was then made for one case of Hurricane Gilbert (1988) to demonstrate that the quasi-steady asymmetric structure analyzed in the idealized studies could be identified in this real data case. Vorticity analysis in the variable f experiment indicated that quasi-steady asymmetries resulted in the eyewall region through the effect of vorticity advection due to differences between the beta gyre flow in the lower free atmosphere and the storm motion. This was roughly matched with a persistent area of divergence and vorticity compression in the lower free atmosphere ahead of the storm and enhanced convergence and vorticity stretching to the rear. An asymmetric structure in the upward motion and accumulated precipitation, when averaged over a sufficiently long period of time, exhibited a corresponding maximum in the eyewall's rear quadrant. With the addition of an easterly basic flow, a pronounced change in the asymmetry of the time-averaged boundary layer convergence resulted, with maximum convergence located ahead of the storm. However, the asymmetries in the average vertical motion in the middle troposphere and accumulated precipitation were more affected by the convergence field in the lower free atmosphere produced by the relative flow there. The relative Bow depended on both the basic and beta gyre flow. With the addition of an easterly vertical shear to the easterly basic Flow, the storm moved faster than the lower-level winds, and strong relative wind was from the front to the rear in the lower free atmosphere and from the opposite direction in the outflow layer aloft. As a result, the upward motion was significantly increased in the front of the storm and reduced in the rear, and the precipitation maximum shifted to the left front quadrant. Overall, analysis results suggest that the flow relative to the storm motion is an important factor contributing to the formation of quasi-steady asymmetries in the convergence and vertical motion fields, as well as in the mean precipitation pattern of tropical cyclones. RP Bender, MA (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,POB 308,PRINCETON,NJ 08542, USA. NR 33 TC 137 Z9 151 U1 0 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 15 PY 1997 VL 54 IS 6 BP 703 EP 724 DI 10.1175/1520-0469(1997)054<0703:TEORFO>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WM594 UT WOS:A1997WM59400002 ER PT J AU Chen, WY vandenDool, HM AF Chen, WY vandenDool, HM TI Asymmetric impact of tropical SST anomalies on atmospheric internal variability over the North Pacific SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NATIONAL-METEOROLOGICAL-CENTER; 3-DIMENSIONAL INSTABILITY THEORY; GENERAL-CIRCULATION MODEL; TELECONNECTION PATTERNS; GEOPOTENTIAL HEIGHTS; TRANSIENT EDDIES; MEAN-FLOW; BLOCKING; PREDICTABILITY; HEMISPHERE AB A substantial asymmetric impact of tropical Pacific SST anomalies on the internal variability of the extratropical atmosphere is found. A variety of diagnoses is performed to help reveal the dynamical processes leading to the large impact. Thirty-five years of geopotential heights and 29 years of wind fields analyzed operationally at the National Centers for Environmental Prediction (NCEP), formerly the National Meteorological Center, and three sets of 10-yr-long perpetual January integrations run with a low-resolution NCEP global spectral model are investigated in detail for the impact of the SST anomalies on the blocking flows over the North Pacific. The impact on large-scale deep trough flows is also examined. Both the blocking and deep trough Bows develop twice as much over the North Pacific during La Nina as during El Nino winters. Consequently, the internal dynamics associated low-frequency variability (LFV), with timescales between 7 and 61 days examined in this study, display distinct characteristics: much larger magnitude for the La Nina than the El Nino winters over the eastern North Pacific, where the LFV is highest in general. The diagnosis of the localized Eliassen-Palm fluxes and their divergence reveals that the high-frequency transient eddies (1-7 days) at high latitudes are effective in forming and maintaining the large-scale blocking flows, while the midlatitude transients are less effective. The mean deformation field over the North Pacific is much more diffluent for the La Nina than the El Nino winters, resulting in more blocking flows being developed and maintained during La Nina by the high-frequency transients over the central North Pacific. In addition to the above dynamical process operating on the high-frequency end of the spectrum, the local barotropic energy conversion between the LFV components and the time-mean Bows is also operating and playing a crucial role. The kinetic energy conversion represented by the scalar product between the E vector of the low-frequency components and the deformation D vector of the time-mean flow reveals that, on average, the low-frequency components extract energy from the time-mean flow during La Nina winters while they lose energy to the time-mean Bow during El Nino winters. This local barotropic energy conversion on the low-frequency end of the spectrum, together with the forcing of the high-frequency transients on blocking flows on the high-frequency end, explain why there is a large difference in the magnitude of low-frequency variability between the La Nina and the El Nino winters. RP NOAA, PREDICT BRANCH,CLIMATE PREDICT CTR,NWS,NMC, NCEP, WASHINGTON, DC 20233 USA. NR 52 TC 44 Z9 45 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 15 PY 1997 VL 54 IS 6 BP 725 EP 740 DI 10.1175/1520-0469(1997)054<0725:AIOTSA>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WM594 UT WOS:A1997WM59400003 ER PT J AU Atkinson, DB Irikura, KK Hudgens, JW AF Atkinson, DB Irikura, KK Hudgens, JW TI Electronic structure of the BF2 radical determined by ab initio calculations and resonance-enhanced multiphoton ionization spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID INFRARED-SPECTRA; BASIS-SETS; BORON; ATOMS; PREDICTION; ABSORPTION; FEATURES; ENERGIES; SI(100); STATES AB We report the first electronic absorption spectrum of the baron difluoride radical. This spectrum appeared in mass-selected multiphoton ionization spectra between 235 and 420 nm. Strong bent-linear structure changes prevented observations of electronic origin bands. EOM-CCSD ab initio calculations suggest that the observed vibrational bands arise from (A) over tilde(2)B(1)<--(X) over tilde(2)A(1) (T-vert = 35 100 cm(-1)) one-photon absorption and from (B) over tilde(2)A(1) (3S) <--<-- (X) over tilde(2)A(1) (T-vert = 59 100 cm(-1)) and (C) over tilde (3p) <--<-- (X) over tilde(2)A(1) (T-vert = 63 100 cm(-1)) two-photon transitions. Ab initio calculations predicted the geometries and vibrational frequencies of the ground states of the BF2 radical, cation, and anion. Ab initio calculations also predicted the vertical transition energies to the excited electronic states from the ground state radical. QCISD(T) calculations estimate ionization potentials for BF2 radicals of IPa = 8.66 eV and IPv = 10.44 eV and adiabatic and vertical electron detachment energies for BR(2)(-) of EA = 1.14 eV and VDE = 1.64 eV. We estimate these ionization and detachment energies to be reliable to about 0.05 and 0.10 eV, respectively. C1 NIST,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. OI Irikura, Karl/0000-0001-7515-6761 NR 42 TC 8 Z9 8 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 13 PY 1997 VL 101 IS 11 BP 2045 EP 2049 DI 10.1021/jp9623251 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WM884 UT WOS:A1997WM88400009 ER PT J AU Alfassi, ZB Neta, P Beaver, B AF Alfassi, ZB Neta, P Beaver, B TI Radiolytic studies of the mechanism of autoxidation of triphenylphosphine and related compounds SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PULSE-RADIOLYSIS; PEROXYL RADICALS; RATE CONSTANTS; OXIDATION AB Triphenylphosphine (Ph(3)P) undergoes one-electron oxidation in irradiated CH2Cl2 solutions to yield the radical cation Ph(3)P(.+). This short-lived species exhibits intense absorption with a maximum at 325 nm and an extended shoulder at 400-500 nm and decays by a second-order process in the absence of O-2. In the presence of O-2, however, the radical cation reacts with O-2 with a rate constant of 7 x 10(6) L mol(-1) s(-1) to yield a peroxyl radical, Ph(3)P(+)OO(.), which exhibits no significant absorbance at lambda > 300 nm. Similar results, but with slightly different rate constants, were obtained also in CCl4 solutions and in CH3CN and cyclohexane solutions containing 1% CCl4. Tris(2,4,6-trimethoxyphenyl)phosphine in CH2Cl2 exhibits a behavior similar to that of Ph(3)P, but the reaction of its radical cation with O-2 is an order of magnitude more rapid. On the other hand, the perfluorinated Ph(3)P(.+) in CH2Cl2 reacts with O-2 much more slowly, if at all. Diphenyl-2-pyridylphosphine yields a radical cation which exhibits a slightly narrower absorption band but reacts with O-2 With the same rate constant as Ph(3)P(.+). The peroxyl radicals propagate a chain reaction by further oxidation of phosphine molecules to Ph(3)P(.+) either directly or indirectly. The final radiolysis product is the phosphine oxide, Ph(3)PO. The radiolytic yields for oxidation of the phosphines were much higher than the radiolytic yield of the solvent derived radicals, except for the case of the perfluoro derivative, and were dependent on the concentrations of phosphine and O-2 and on the dose rate. At low dose rates and high solute concentrations the chain lengths exceeded 1000. C1 NIST,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. DUQUESNE UNIV,DEPT BIOCHEM & CHEM,PITTSBURGH,PA 15282. BEN GURION UNIV NEGEV,IL-84105 BEER SHEVA,ISRAEL. NR 28 TC 36 Z9 36 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 13 PY 1997 VL 101 IS 11 BP 2153 EP 2158 DI 10.1021/jp9637486 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WM884 UT WOS:A1997WM88400024 ER PT J AU Rightor, EG Hitchcock, AP Ade, H Leapman, RD Urquhart, SG Smith, AP Mitchell, G Fischer, D Shin, HJ Warwick, T AF Rightor, EG Hitchcock, AP Ade, H Leapman, RD Urquhart, SG Smith, AP Mitchell, G Fischer, D Shin, HJ Warwick, T TI Spectromicroscopy of poly(ethylene terephthalate): Comparison of spectra and radiation damage rates in x-ray absorption and electron energy loss SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID CORE EXCITATION SPECTROSCOPY; INNER-SHELL SPECTROSCOPY; PHOTOELECTRON-SPECTROSCOPY; MICROSCOPY; POLY(ETHYLENE-TEREPHTHALATE); MICROANALYSIS; ORIENTATION; DEPENDENCE; MOLECULES; POLYMERS AB The C 1s and O 1s X-ray absorption spectra of poly(ethylene terephthalate) (PET) have been recorded using transmission, fluorescence, and electron yield detection. The corresponding electron energy loss spectra (EELS) have been recorded in a scanning transmission electron microscope. These results are compared to the C 1s and O 1s spectra of gas phase 1,4-dimethyl terephthalate (the monomer of PET) recorded using EELS. The comparison of monomer and polymer materials in different phases and with different techniques has aided the understanding of the relative strengths and limitations of each technique as well as assisting the spectral interpretation. Good agreement is found in the overall shape and the energies of the spectral features. Relatively minor differences in intensities can be understood in terms of the properties of the individual spectroscopic techniques. The critical dose for radiation damage by 100 keV electrons incident on PET at 100 K is found to be (1.45 +/- 0.15) x 10(3) eV nm(-3). In contrast, the critical dose for radiation damage by 302 eV X-rays incident on PET at 300 K is (1.2 +/- 0.6) x 10(4) eV nm(-3). A figure of merit involving the product of critical energy dose and spectral efficiency (as expressed by the appropriate G value) is developed. This indicates that, for near-edge studies involving a 20 eV spectral width, there is similar to 500-fold advantage of X-ray absorption studies on room temperature PET relative to electron energy loss studies of cooled PET. C1 MCMASTER UNIV, DEPT CHEM, HAMILTON, ON L8S 4M1, CANADA. DOW CHEM CO USA, FREEPORT, TX 77541 USA. N CAROLINA STATE UNIV, DEPT PHYS, RALEIGH, NC 27695 USA. NIH, BEIP, NCRR, BETHESDA, MD 20892 USA. DOW CHEM CO USA, MIDLAND, MI 48667 USA. NATL INST STAND & TECHNOL, MAT SCI & ENGN LAB, GAITHERSBURG, MD 20899 USA. POHANG LIGHT SOURCE, POHANG, SOUTH KOREA. LAWRENCE BERKELY NATL LAB, BERKELEY, CA 91420 USA. RI Ade, Harald/E-7471-2011; Urquhart, Stephen/A-6237-2014 OI Urquhart, Stephen/0000-0002-6415-6341 NR 66 TC 123 Z9 123 U1 2 U2 23 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAR 13 PY 1997 VL 101 IS 11 BP 1950 EP 1960 DI 10.1021/jp9622748 PG 11 WC Chemistry, Physical SC Chemistry GA WM886 UT WOS:A1997WM88600004 ER PT J AU Nucci, JA Keller, RR Field, DP ShachamDiamand, Y AF Nucci, JA Keller, RR Field, DP ShachamDiamand, Y TI Grain boundary misorientation angles and stress-induced voiding in oxide passivated copper interconnects SO APPLIED PHYSICS LETTERS LA English DT Article ID LINES AB Grain boundary misorientations were determined by electron backscattering diffraction for tantalum-encapsulated, copper interconnects which contained thermal-stress-induced voids. The misorientation angles at voided and unvoided line segments were analyzed for two differently heat treated sample types, which were not equally susceptibile to stress voiding. Unvoided line segments contained a larger percentage of low misorientation angle, lower diffusivity boundaries than regions adjacent to voids. In addition, the mow void resistant sample type also contained an overall higher proportion of low misorientation angle boundaries than the sample type which exhibited more voiding. The data provide further support for the importance of local variations in microstructure, which control the kinetics of stress void formation and growth. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL,DIV MAT RELIABIL,BOULDER,CO 80303. TEXSEM LABS INC,PROVO,UT 84604. RP Nucci, JA (reprint author), CORNELL UNIV,SCH ELECT ENGN,PHILLIPS HALL,ITHACA,NY 14853, USA. RI Keller, Robert/I-9014-2012; Field, David/D-5216-2012 OI Field, David/0000-0001-9415-0795 NR 13 TC 47 Z9 48 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAR 10 PY 1997 VL 70 IS 10 BP 1242 EP 1244 DI 10.1063/1.118942 PG 3 WC Physics, Applied SC Physics GA WL865 UT WOS:A1997WL86500019 ER PT J AU Frohlich, C Coffin, MF Massell, C Mann, P Schuur, CL Davis, SD Jones, T Karner, G AF Frohlich, C Coffin, MF Massell, C Mann, P Schuur, CL Davis, SD Jones, T Karner, G TI Constraints on Macquarie Ridge tectonics provided by Harvard focal mechanisms and teleseismic earthquake locations SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID DAY PLATE MOTIONS; OCEANIC FRACTURE; RUPTURE PROCESS; SEISMICITY; CONSISTENCY; PARAMETERS; COMPLEX; STRESS; SEA AB In this study we evaluate teleseismically determined focal mechanisms and epicenters for earthquakes along the Macquarie Ridge Complex (MRC) from 45 degrees S to 61 degrees S and 155 degrees E to 168 degrees E, a region characterized by some previous investigators as undergoing subduction initiation. From 65 centroid moment tensors reported by Harvard, we develop statistical guidelines for choosing 26 which represent better determined, more reliable focal mechanisms for tectonic analysis. Although thrust mechanisms occur in the north, near Fiordland, elsewhere along the MRC the better determined mechanisms virtually all indicate that present-day motion along most of the MRC is strike-slip. This is consistent with sidescan sonar and multichannel reflection data collected between 50 degrees S and 57 degrees S on 1994 and 1996 cruises; the active plate boundary zone appears to be quite narrow (< 5 km wide), and no active compressional features can be observed on the seafloor. If we determine a rotation pole for plate boundary motion using only slip vectors from better determined Harvard mechanisms along the MRC, the best fitting ''instantaneous'' pole is at 57.4 degrees S, 179.4 degrees E, about 2.5 degrees north of the NUVEL-I Australian-Pacific pole, which averages motion over the last 3.0 my. If the MRC pole was formerly farther south than at present, this could explain the existence of relict features associated with crustal shortening, such as bathymetric highs and troughs; yet, the absence of active features such as thrust faults, etc., suggests ongoing compression or subduction initiation. We also carefully read arrival times for P phases for 53 earthquakes at 16 teleseismic stations, selected to represent a range of azimuths surrounding the earthquakes; we relocated these earthquakes using standard joint epicentral determination (JED) methods. While most of the better quality relocations lie on or very close to the Australia-Pacific boundary as determined on the 1994 cruise, a few epicenters occur well away from the boundary, apparently on Cenozoic fracture zones. Thus, on the Macquarie Ridge Complex and other major strike-slip boundaries (e.g., in California), it appears that the very largest earthquakes occur on the principal plate boundary fault but that other earthquakes, some quite large, may occur away from the boundary along zones of preexisting weakness. C1 NOAA, NATL GEOPHYS DATA CTR, CIRES, BOULDER, CO 80303 USA. AUSTRALIAN GEOL SURVEY ORG, CANBERRA, ACT 2601, AUSTRALIA. COLUMBIA UNIV, LAMONT DOHERTY EARTH OBSERV, PALISADES, NY 10964 USA. RP Frohlich, C (reprint author), UNIV TEXAS, INST GEOPHYS, 8701 N MOPAC BLVD, AUSTIN, TX 78759 USA. RI Mann, Paul/A-2077-2009; Frohlich, Cliff/A-8573-2008; Coffin, Millard/H-4619-2011 OI Coffin, Millard/0000-0001-9960-0038 NR 46 TC 33 Z9 37 U1 0 U2 0 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 1997 VL 102 IS B3 BP 5029 EP 5041 DI 10.1029/96JB03408 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WM584 UT WOS:A1997WM58400007 ER PT J AU Julienne, PS Mies, FH Tiesinga, E Williams, CJ AF Julienne, PS Mies, FH Tiesinga, E Williams, CJ TI Collisional stability of double bose condensates SO PHYSICAL REVIEW LETTERS LA English DT Article ID EINSTEIN CONDENSATION; ATOMIC-HYDROGEN AB This paper presents quantitative calculations of collisional loss rates for pure Na-23 or Rb-87 atoms in a binary mixture of hyperfine states \F, M]. We find that the recent observation of a dual Bose condensate consisting of Rb-87 \1, -1] and \2, 2] atoms is unique and will not occur in Na. We attribute this to the unexpectedly small inelastic spin-exchange rate associated with Rb-87 s-wave hyperfine collisions. This fortuitous result arises from nearly equal (5.45 +/- 0.26 nm) scattering lengths for two colliding Rb-87 atoms in their \1, -1] or \2, 2] states. C1 UNIV CHICAGO, JAMES FRANCK INST, CHICAGO, IL 60637 USA. RP NATL INST STAND & TECHNOL, ATOM PHYS DIV, GAITHERSBURG, MD 20899 USA. RI Williams, Carl/B-5877-2009; Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 15 TC 96 Z9 97 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAR 10 PY 1997 VL 78 IS 10 BP 1880 EP 1883 DI 10.1103/PhysRevLett.78.1880 PG 4 WC Physics, Multidisciplinary SC Physics GA WM064 UT WOS:A1997WM06400013 ER PT J AU Loomis, RA Klaassen, JJ Lindner, J Christopher, PG Leone, SR AF Loomis, RA Klaassen, JJ Lindner, J Christopher, PG Leone, SR TI Fourier transform infrared emission study of the mechanism and dynamics of HOI formed in the reaction of alkyl iodides with O(P-3) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID UNIMOLECULAR ELIMINATION-REACTIONS; OZONE DEPLETION; GAS-PHASE; STRATOSPHERE; PHOTOLYSIS; PHOTODISSOCIATION; CHLORINE; IODINE; ENERGY; OH AB Vibrationally excited hypoiodous acid (HOI) is observed as a product in the reaction of alkyl iodides with O(P-3). Fourier transform infrared emission techniques are used to detect the excited nu(1), OH, stretch of the HOI product, to determine the mechanism of HOI production, and to measure the vibrational product state distributions. The HOI product is formed by O atom reaction with two-carbon and larger straight or branched chain alkyl iodides and cyclic alkyl iodides, e.g., C2H5I, n-C3H7I, i-C3H7I, (CH3)(3)CI, n-C6H13I, and c-C6H11I, but not with CH3I. Experiments with selectively deuterated ethyl iodides provide direct evidence that HOI is formed in a beta-elimination mechanism involving a five-membered ring transition state. The O atom attacks the iodine and then abstracts a hydrogen from the beta carbon during the lifetime of the complex. Time-resolved experiments allow the extraction of nascent vibrational state distributions for the nu(1) stretch of HOI (upsilon=1:upsilon=2:upsilon=3) using different alkyl iodides and assuming the radiative rates are given by A(nu-->nu-1=upsilon A?(1-->0): C2H5I, 0.53(4):0.39(3):0.08(3); n-C3H7I, 0.61(6):0.34(5):0.05(2); and i-C3H7I, 0.54(6):0.38(4):0.08(3). These distributions are nonstatistical with the upsilon=2 states having only slightly less population than those with upsilon=1. For product molecules with up to three quanta of vl excitation, more than 50% of the reaction exothermicity is deposited into the OH stretch. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Loomis, RA (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 66 TC 29 Z9 29 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 8 PY 1997 VL 106 IS 10 BP 3934 EP 3947 DI 10.1063/1.473510 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WL946 UT WOS:A1997WL94600012 ER PT J AU Margolis, SA Schapira, RM AF Margolis, SA Schapira, RM TI Liquid chromatographic measurement of L-ascorbic acid and D-ascorbic acid in biological samples SO JOURNAL OF CHROMATOGRAPHY B LA English DT Article DE ascorbic acid; vitamins ID CYTOCHROME-C REDUCTION; ISOASCORBIC ACID; DEHYDROASCORBIC ACID; ELECTROCHEMICAL DETECTION; DEHYDROISOASCORBIC ACID; QUANTITATIVE-ANALYSIS; ERYTHORBIC ACID; HUMAN-PLASMA; VITAMIN-C; SEPARATION AB D- and L-Ascorbic acids have been separated using liquid chromatography (LC) on a polymer-coated silica-based NH2 column and the L-isomer has been quantified in human serum, rat serum, rat lung, rat lung perfusate, infant formula (SRM 1846) and mixed food sample (SRM 2383). The D-isomer was observed only in trace amounts in the mixed food sample. The results demonstrate that ascorbic acid was stable on the column and completely recovered from supplemented samples of human serum and that this method of analysis is accurate, precise and has broad application exhibiting no dependence on the nature of the matrices evaluated herein. C1 ZABLOCKI VET ADM MED CTR,SECT PULM CRIT CARE MED,MILWAUKEE,WI 53295. MED COLL WISCONSIN,DEPT MED,MILWAUKEE,WI 53226. RP Margolis, SA (reprint author), NIST,CHEM SCI & TECHNOL LAB,QUINCE ORCHARD RD,GAITHERSBURG,MD 20899, USA. FU NCI NIH HHS [Y01-CN-30698, Y01-CP9-0506]; PHS HHS [K08-239] NR 25 TC 36 Z9 37 U1 4 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4347 J9 J CHROMATOGR B JI J. Chromatogr. B PD MAR 7 PY 1997 VL 690 IS 1-2 BP 25 EP 33 DI 10.1016/S0378-4347(96)00401-X PG 9 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA WV315 UT WOS:A1997WV31500004 PM 9106026 ER PT J AU Burns, TJ Davis, RW Moore, EF AF Burns, TJ Davis, RW Moore, EF TI Dynamical systems approach to particle transport modeling in dilute gas-particle flows with application to a chemical vapor deposition reactor SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article AB A general method for treating the transport of particles in dilute gas-particle flows is presented. This method formulates the particle transport equations as a dynamical system and utilizes the corresponding theory to analyze the resulting dynamics. As an illustration of this technique, the transport of contaminant particles in a barrel-type chemical vapor deposition reactor is analyzed. The background gas flow field is determined via a numerical simulation of the Navier-Stokes equations. The analysis reveals the presence of particle attractors in the how which are particle size specific. The features of these attractors are discussed, as is their behavior with varying particle size. (C) 1997 American Association for Aerosol Research. C1 NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. RP Burns, TJ (reprint author), NIST,COMP & APPL MATH LAB,BLDG 820,ROOM 365,GAITHERSBURG,MD 20899, USA. NR 30 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD MAR PY 1997 VL 26 IS 3 BP 193 EP 211 DI 10.1080/02786829708965425 PG 19 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA WK868 UT WOS:A1997WK86800002 ER PT J AU Paul, RL AF Paul, RL TI Hydrogen measurement by prompt gamma-ray activation analysis - A review SO ANALYST LA English DT Review DE hydrogen; prompt gamma rays; activation analysis; cold neutrons ID NEUTRON-SCATTERING; MULTIELEMENT ANALYSIS; STANDARDS; FACILITY; ELEMENTS; NIST RP Paul, RL (reprint author), NIST,DIV ANALYT CHEM,GAITHERSBURG,MD 20899, USA. NR 45 TC 34 Z9 34 U1 0 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0003-2654 J9 ANALYST JI Analyst PD MAR PY 1997 VL 122 IS 3 BP R35 EP R41 DI 10.1039/a606419a PG 7 WC Chemistry, Analytical SC Chemistry GA WP439 UT WOS:A1997WP43900001 ER PT J AU Wells, GD Rodger, AS Moffett, RJ Bailey, GJ FullerRowell, TJ AF Wells, GD Rodger, AS Moffett, RJ Bailey, GJ FullerRowell, TJ TI The effects of nitric oxide cooling and the photodissociation of molecular oxygen on the thermosphere/ionosphere system over the Argentine Islands SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article ID MODEL; IONOSPHERE; SPECTRUM AB In the past the global, fully coupled, time-dependent mathematical model of the Earth's thermosphere/ionosphere/plasmasphere (CTIP) has been unable to reproduce accurately observed values of the maximum plasma frequency, foF2, at extreme geophysical locations such as the Argentine Islands during the summer solstice where the ionosphere remains in sunlight throughout the day. This probably because the This seasonal dependence of thermospheric cooling by 5.3 mu m nitric oxide has been neglected and the photodissociation of O-2 and heating rate calculations have been over-simplified. Now we have included an up-to-date calculation of the solar EUV and UV thermospheric heating rate, coupled with a new calculation of a photodissociation rate, in the model. Seasonally dependent 5.3 Irm nitric oxide cooling is also included. With these important improvements, it is found that model values of foF2 are in substantially better agreement with observation. The height of the F2-peak is reduced throughout the day, but remains within acceptable limits of values derived from observation, except at around 0600 h LT. We also carry out two studies of the sensitivity of the upper atmosphere to changes in the magnitude of nitric oxide cooling and photodissociation rates. We find that hmF2 increases with increased heating, whilst foF2 falls. The converse is true for an increase in the cooling rate. Similarly increasing the photodissociation rate increases both hmF2 and foF2. These changes are explained in terms of changes in the neutral temperature, composition and neutral wind. C1 BRITISH ANTARCTIC SURVEY, CAMBRIDGE CB3 0ET, ENGLAND. UNIV COLORADO, NOAA, COOPERAT INST RES ENVIRONM SCI, SPACE ENVIRONM LAB, BOULDER, CO 80303 USA. RP UNIV SHEFFIELD, SCH MATH & STAT, HICKS BLDG, SHEFFIELD S3 7RH, S YORKSHIRE, ENGLAND. NR 22 TC 5 Z9 5 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 1997 VL 15 IS 3 BP 355 EP 365 DI 10.1007/s00585-997-0355-0 PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA WM891 UT WOS:A1997WM89100008 ER PT J AU Zimmerman, BE Colle, R AF Zimmerman, BE Colle, R TI Cocktail volume effects in 4 pi beta liquid scintillation spectrometry with H-3-standard efficiency tracing for low-energy beta-emitting radionuclides SO APPLIED RADIATION AND ISOTOPES LA English DT Article ID STANDARDIZATION AB The effect of total liquid scintillation (LS) cocktail volume (or mass) in the 4 pi beta LS spectrometry of beta-emitting radionuclides has been investigated. The magnitude of such possible volume effects on the apparent activity of low-energy beta-emitting radionuclides, as determined by the CIEMAT/NIST H-3-standard efficiency tracing method, as well as any systematic trends in the relative detection efficiencies of low-energy beta-emitters were studied. The radionuclides chosen for the study, Ni-63 and Cl-36, were traced against H-3. Detection efficiency losses, as a function of total LS cocktail volume, were found to be energy-dependent. Because of the low E(beta,max) for the decay of H-3 and Ni-63, systematic losses in the efficiency with increasing cocktail mass, as well as at extremely low (<5 g) masses were observed. The determination of quench-indicating parameters, even for cocktails of uniform composition, were also found to be volume-dependent. Despite a relatively large (17%) variation in the H-3 counting efficiency over the volume range 1-20 mL in 22 mL vials and a corresponding 7% variation in the Ni-63 counting efficiency, the CIEMAT/NIST method was able to trace the observed Ni-63 activity to about 0.1%. No volume effect on the observed relative efficiency of Cl-36 was found. The best condition for repeatability in the determination of the massic activity of a single sample was found to be when the volume is 8-12 mL in a 22 mL vial. The effect of total LS cocktail volume on the efficiency-traced massic activities was found to have no clear, consistent trend and proved difficult to quantify. Nonetheless, two approaches to estimating the magnitude of the effect are presented and indicate that it is extremely small (<0.1%) and was within the statistical variation of the measurements. Published by Elsevier Science Ltd. RP Zimmerman, BE (reprint author), NATL INST STAND & TECHNOL,PHYS LAB,GAITHERSBURG,MD 20899, USA. NR 27 TC 13 Z9 14 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAR PY 1997 VL 48 IS 3 BP 365 EP 378 DI 10.1016/S0969-8043(96)00217-5 PG 14 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA WL882 UT WOS:A1997WL88200010 ER PT J AU Asgard, T Shearer, KD AF Asgard, T. Shearer, K. D. TI Dietary phosphorus requirement of juvenile Atlantic salmon, Salmo salar L. SO AQUACULTURE NUTRITION LA English DT Article DE Atlantic salmon; dietary requirement; phosphorus AB The objective of this study was to determine the dietary phosphorus (P) requirement of juvenile Atlantic salmon, Salmon salar L. Triplicate groups of fish (mean initial weight 1.4 g) were fed semipurified, casein-gelatine-based diets containing one of five levels of P (4, 8, 10, 15 and 25 g kg(-1)) from Ca(H2PO4)(2)center dot H2O, or a commercial feed (17 g kg(-1) P) for 9 weeks. Weight gains did not differ significantly among treatment groups fed the experimental diets but were slightly less than gains in fish fed the commercial feed. Feed efficiency (wet weight gain/dry feed consumed) was similar in all groups, averaging 1.45. Availability of dietary P, estimated from apparent retention and apparent digestibility, was 86%. Whole-body P concentrations declined in fish fed diets containing less than 10 g kg(-1) P. Fitting a logistic curve to dietary P vs. whole-body P concentrations indicated that a minimum of 11 g kg(-1) dietary P (9 g kg(-1) digestible P) was required by juvenile Atlantic salmon to maintain whole-body P concentrations at initial levels. Calculation of a dietary requirement using a simple factorial model which incorporated measurements of P availability, feed efficiency and normal whole-body P concentration indicated that the dietary requirement was approximately 10g kg(-1). The dietary requirement established in this study (10(-11)g kg(-1)) is higher than previously reported for Atlantic salmon or other fishes. Possible reasons for the wide range of reported dietary P requirements in fishes are discussed. C1 [Shearer, K. D.] NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. [Asgard, T.] Inst Aquaculture Res Ltd AKVAFORSK, Sunndalsora, Norway. RP Shearer, KD (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. FU Norwegian State Pollution Control Authorities; Bank of Industrial Development; Biomar Ltd (Trondheim, Norway) FX We wish to acknowledge the Norwegian State Pollution Control Authorities, The Bank of Industrial Development and Biomar Ltd (Trondheim, Norway) for financial support. We thank Erich Gauglitz Jr and Jo ann Lund of NWFSC, NMFS and Arild Linseth at AKVAFORSK for technical support and Dr R. W. Hardy for helpful comments on the manuscript. NR 35 TC 74 Z9 86 U1 0 U2 13 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1353-5773 J9 AQUACULT NUTR JI Aquac. Nutr. PD MAR PY 1997 VL 3 IS 1 BP 17 EP 23 DI 10.1046/j.1365-2095.1997.00069.x PG 7 WC Fisheries SC Fisheries GA V27EZ UT WOS:000208597800003 ER PT J AU Zelenka, MP AF Zelenka, MP TI An analysis of the meteorological parameters affecting ambient concentrations of acid aerosols in Uniontown, Pennsylvania SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE particulate matter; human exposure; meteorology; regional transport; synoptic climatology; principal components analysis; cluster analysis; linear regression ID SYNOPTIC CLIMATOLOGICAL CLASSIFICATION; OZONE; POLLUTION; AIR; TRANSPORT; SYSTEM; GASES AB Ambient concentrations of aerosol strong acidity (H+) that were collected in Uniontown, Pennsylvania, during the summer of 1990 were evaluated to determine the relationships between meteorology and the magnitude of the H+ concentrations. An extensive database containing 17 meteorological parameters was compiled for the Uniontown - Pittsburgh region. The database included both surface and upper air meteorological parameters. Concentrations of ambient acid sulfate aerosols collected in Uniontown, Pennsylvania, in the summer of 1990 were greatly affected by both local and regional meteorological conditions. Seven distinct meteorological synoptic types or regimes were identified for the summer months. A clear association was shown between episodic events of elevated ambient H+ concentrations and one of the regimes, referred to here as synoptic type 5, which occurred when an anticyclone set up to the east of the mid-Atlantic states. Much of the variability (approximately 45%) in H+ concentrations for the overall model was explained by the surface air temperature. Approximately 10% of the H+ variability was explained by westerly winds as expressed by the U components of the morning 850 mb wind and the mean daily surface wind at Uniontown. Results showed that for days under the influence of synoptic type 5, which was associated with the highest levels of ambient H+, the surface temperature explained approximately one-third of the variability in H+ concentrations. The height of the mixing layer also affected the variability in H+ concentrations, accounting for nearly a quarter of the variance. These results show that an analysis of the surface wind speed and direction alone will not adequately explain the variability in the concentrations of ambient acid aerosols. Analyses of the meteorological parameters affecting ambient concentrations of acid aerosols should include the mixing height, as well as the temperature, wind speed, and wind direction; both at the surface and for an upper level of the atmosphere that facilitates regional transport of pollutants. Copyright (C) 1996 Elsevier Science Ltd RP Zelenka, MP (reprint author), NOAA,ATMOSPHER SCI MODELING DIV,AIR RESOURCES LAB MD 56,RES TRIANGLE PK,NC 27711, USA. NR 28 TC 16 Z9 17 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAR PY 1997 VL 31 IS 6 BP 869 EP 878 DI 10.1016/S1352-2310(96)00237-3 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA WB867 UT WOS:A1997WB86700009 ER PT J AU Hwang, D Byun, DW Odman, MT AF Hwang, D Byun, DW Odman, MT TI An automatic differentiation technique for sensitivity analysis of numerical advection schemes in air quality models SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE sensitivity coefficients; ADIFOR; advection process ID SYSTEMS AB Sensitivity analysis, which characterizes the change in model output due to variations in model input parameters, is of critical importance in simulation models. Sensitivity coefficients, defined as the partial derivatives of the model output with respect to the input parameters, are useful in assessing the reliability of the output from a complex model with many uncertainty parameters. Most existing sensitivity methods, however, have one or more of the following limitations: inaccuracy in the results, high cost in human effort, and difficulty in mathematical formulation and computer program implementation. To overcome these limitations, we are exploring ADIFOR, an automatic differentiation technique for systematically studying sensitivities. One can apply ADIFOR without having an intimate knowledge of the algorithms implemented in a model, sb manual preparation of sensitivity code is avoided. In this paper, ADIFOR's accuracy and computational efficiency are demonstrated by calculating the sensitivity of concentration to a global perturbation of wind velocity in advection models and comparing this with results from the brute-force method of sensitivity analysis. ADIFOR-generated code can produce exact sensitivity information up to the machine epsilon, and can reduce computer CPU time requirements by up to 57% compared with the brute-force method for a single sensitivity calculation (and the savings increases with the number of parameters). Furthermore, we demonstrate the applicability of ADIFOR to models with a large number of uncertainty parameters by calculating the sensitivity of model output to initial conditions in a two-dimensional advection model. Copyright (C) 1996 Elsevier Science Ltd C1 MCNC, N CAROLINA SUPERCOMP CTR, ENVIRONM PROGRAMS, RES TRIANGLE PK, NC 27709 USA. NOAA, ATMOSPHER SCI MODELING DIV, AIR RESOURCES LAB, RES TRIANGLE PK, NC 27711 USA. RI Odman, Mehmet/L-6218-2013 OI Odman, Mehmet/0000-0002-3947-7047 NR 14 TC 22 Z9 23 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 EI 1873-2844 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAR PY 1997 VL 31 IS 6 BP 879 EP 888 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA WB867 UT WOS:A1997WB86700010 ER PT J AU Tsang, W Bedanov, V Zachariah, MR AF Tsang, W Bedanov, V Zachariah, MR TI Unimolecular decomposition of large organic radicals with low reaction thresholds: Decomposition and reversible isomerization of n-pentyl radicals SO BERICHTE DER BUNSEN-GESELLSCHAFT-PHYSICAL CHEMISTRY CHEMICAL PHYSICS LA English DT Article; Proceedings Paper CT Discussion Meeting of the Deutsche-Bunsen-Gesellschaft on Unimolecular Reactions CY OCT 21-24, 1996 CL TUTZING, GERMANY SP Deut Bunsen Gesell DE chemical kinetics; elementary reactions; energy transfer; cases; radicals ID ALKYL RADICALS AB The decomposition kinetics of n-pentyl radicals in the high temperature regime where steady state distributions are not achieved and reversible isomerization to decomposing 2-pentyl radicals is of importance has been analyzed through the solution of the time-dependent master equation. The reactions are characterized by low activation thresholds and lead to large rate constants that vary with time. Particular attention is paid to branching ratios for direct decomposition of the n-pentyl radical and the decomposition that follows reversible isomerization to the 2-pentyl species. The behavior of the system under a variety of conditions is described and the use of branching ratios as a possible means of characterizing the reactions in a manner that is compatible with present methods for employing kinetic data for simulating complex chemical phenomenon is considered. At higher temperatures, rate constants and branching ratios collapse to limiting values. The combination of limiting and the onset of steady state behavior complicates the situation at lower temperatures. The overall behavior of such systems is highly dependent on the magnitude of the barrier to isomerization. The extent of departures from the high pressure-branching ratios are defined. RP Tsang, W (reprint author), NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 18 TC 35 Z9 35 U1 0 U2 8 PU VCH PUBLISHERS INC PI DEERFIELD BEACH PA 303 NW 12TH AVE, DEERFIELD BEACH, FL 33442-1788 SN 0005-9021 J9 BER BUNSEN PHYS CHEM JI Ber. Bunsen-Ges. Phys. Chem. Chem. Phys. PD MAR PY 1997 VL 101 IS 3 BP 491 EP 499 PG 9 WC Chemistry, Physical SC Chemistry GA WR854 UT WOS:A1997WR85400022 ER PT J AU Gilson, MK Given, JA Bush, BL McCammon, JA AF Gilson, MK Given, JA Bush, BL McCammon, JA TI The statistical-thermodynamic basis for computation of binding affinities: A critical review SO BIOPHYSICAL JOURNAL LA English DT Review ID FREE-ENERGY CALCULATIONS; MOLECULAR-DYNAMICS SIMULATION; HIGH-PRESSURE DISSOCIATION; ABSOLUTE FREE-ENERGIES; AIDED DRUG DESIGN; LIGAND-BINDING; IONIC FLUIDS; RECEPTOR INTERACTIONS; COMPUTER-SIMULATIONS; LACTIC-DEHYDROGENASE AB Although the statistical thermodynamics of noncovalent binding has been considered in a number of theoretical papers, few methods of computing binding affinities are derived explicitly from this underlying theory. This has contributed to uncertainty and controversy in certain areas. This article therefore reviews and extends the connections of some important computational methods with the underlying statistical thermodynamics. A derivation of the standard free energy of binding forms the basis of this review. This derivation should be useful in formulating novel computational methods for predicting binding affinities. It also permits several important points to be established. For example, it is found that the double-annihilation method of computing binding energy does not yield the standard free energy of binding, but can be modified to yield this quantity. The derivation also makes it possible to define clearly the changes in translational, rotational, configurational, and solvent entropy upon binding. It is argued that molecular mass has a negligible effect upon the standard free energy of binding for biomolecular systems, and that the cratic entropy defined by Gurney is not a useful concept. In addition, the use of continuum models of the solvent in binding calculations is reviewed, and a formalism is presented for incorporating a limited number of solvent molecules explicitly. C1 MERCK RES LABS,DEPT MOL DESIGN & DIVERS,RAHWAY,NJ 07065. UNIV CALIF SAN DIEGO,DEPT CHEM & BIOCHEM,LA JOLLA,CA 92093. UNIV CALIF SAN DIEGO,DEPT PHARMACOL,LA JOLLA,CA 92093. RP Gilson, MK (reprint author), NIST,CTR ADV RES BIOTECHNOL,9600 GUDELSKY DR,ROCKVILLE,MD 20850, USA. NR 120 TC 619 Z9 626 U1 17 U2 251 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD MAR PY 1997 VL 72 IS 3 BP 1047 EP 1069 PG 23 WC Biophysics SC Biophysics GA WJ824 UT WOS:A1997WJ82400010 PM 9138555 ER PT J AU Dornbrack, A Nappo, CJ AF Dornbrack, A Nappo, CJ TI A note on the application of linear wave theory at a critical level SO BOUNDARY-LAYER METEOROLOGY LA English DT Article DE stratified flows; critical level; linear wave theory; numerical simulations ID GRAVITY-WAVES; ATMOSPHERE; FLOWS AB The purpose of this note is to estimate the accuracy and practical limitations of applying linear theory at a critical level over a realistic range of atmospheric stabilities for an idealized surface terrain. These estimates are made by comparing the results of a linear model with a nonlinear numerical model at a critical level. Essentially similar results are obtained from each model for wave stress, wave breaking height and wave dissipation through the critical level. Because gravity waves can be either evanescent or internal depending on the relative sizes of the Scorer parameter and the wavenumber of the ground surface disturbance, the somewhat paradoxical result develops that wave breaking and non-linearity increase with increasing bulk Richardson number. It is recommended that steady linear wave theory be used in gravity wave drag parameterizations provided near real time profiles of background velocity and temperature are available. C1 NOAA,ATMOSPHER TURBULENCE & DIFFUS DIV,AIR RESOURCES LAB,OAK RIDGE,TN 37831. RP Dornbrack, A (reprint author), DLR,INST PHYS ATMOSPHARE,D-82230 OBERPFAFFENHOFEN,GERMANY. NR 19 TC 12 Z9 12 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 1997 VL 82 IS 3 BP 399 EP 416 DI 10.1023/A:1000270821161 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WT073 UT WOS:A1997WT07300003 ER PT J AU Holle, RL Lopez, RE Howard, KW Cummins, KL Malone, MD Krider, EP AF Holle, RL Lopez, RE Howard, KW Cummins, KL Malone, MD Krider, EP TI An isolated winter cloud-to-ground lightning flash causing damage and injury in Connecticut SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CALIBRATION; NETWORK AB An isolated lightning flash at 1436:52 UTC 11 February 1996 struck and destroyed a house in Burlington, Connecticut, injuring an occupant of the house. A flash detected simultaneously by the National Lightning Detection Network was within 1.1 km of the house. The flash was separated from any other flash by several hours and hundreds of kilometers and occurred during winter. Positive charge was lowered to ground by the flash, as has been found in previous studies of winter storms. Its estimated peak current of +76 kA was stronger than most positive flashes and nearly all negative cloud-to-ground flashes for the entire year in the same area. The incident is compared with other previously documented lightning casualty and damage statistics during wintertime for Connecticut and other regions of the United States. The importance of the flash is described in relation to the resulting material damage and personal injury, the handling of insurance claims, the use of flash data in forecasting and warning applications, and personal safety. C1 GLOBAL ATMOSPHERES INC,TUCSON,AZ. UNIV ARIZONA,INST ATMOSPHER PHYS,TUCSON,AZ 85721. RP Holle, RL (reprint author), NOAA,NATL SEVERE STORMS LAB,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. NR 15 TC 9 Z9 9 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 1997 VL 78 IS 3 BP 437 EP 441 DI 10.1175/1520-0477(1997)078<0437:AIWCTG>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WW304 UT WOS:A1997WW30400006 ER PT J AU Nappo, CJ Bach, WD AF Nappo, CJ Bach, WD TI Summary report on the ARO/ARL workshop on turbulence and diffusion in the stable planetary boundary layer SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material AB A workshop on turbulence and diffusion in the stable planetary boundary layer (SPBL) was held on 11-13 January 1994 at Arizona State University, Tempe, Arizona. Topics discussed included the interactions of gravity waves with turbulence, observations and data analysis in the SPBL, laboratory experiments in stably stratified fluids, and atmospheric dispersion in the SPBL. This report summaries the presentations and discussions made during the workshop and lists the recommendations made for further research. C1 USA,RES OFF,RES TRIANGLE PK,NC 27709. RP Nappo, CJ (reprint author), NOAA,ENVIRONM RES LABS,ATMOSPHER TURBULENCE & DIFFUS DIV,AIR RESOURCES LAB,POB 2456,OAK RIDGE,TN 37831, USA. NR 0 TC 6 Z9 6 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 1997 VL 78 IS 3 BP 493 EP 498 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WW304 UT WOS:A1997WW30400012 ER PT J AU Hayes, DB Brodziak, JKT AF Hayes, DB Brodziak, JKT TI Efficiency and bias of estimators and sampling designs for determining length-weight relationships of fish - Reply SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Editorial Material C1 NATL MARINE FISHERIES SERV,NW FISHERY SCI CTR,HATFIELD MARINE SCI CTR,NEWPORT,OR 97365. RP Hayes, DB (reprint author), MICHIGAN STATE UNIV,DEPT FISHERIES & WILDLIFE,PARTNERSHIP ECOSYST RES & MANAGEMENT,E LANSING,MI 48824, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAR PY 1997 VL 54 IS 3 BP 744 EP 745 DI 10.1139/cjfas-54-3-744 PG 2 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XB788 UT WOS:A1997XB78800027 ER PT J AU Hall, A Manabe, S AF Hall, A Manabe, S TI Can local linear stochastic theory explain sea surface temperature and salinity variability? SO CLIMATE DYNAMICS LA English DT Article ID GENERAL-CIRCULATION MODEL; CLIMATE MODELS; OCEAN; CO2 AB Sea surface temperature (SST) and salinity (SSS) time series from four ocean weather stations and data from an integration of the GFDL coupled ocean-atmosphere model are analyzed to test the applicability of local linear stochastic theory to the mixed-layer ocean. According to this theory, mixed-layer variability away from coasts and fronts can be explained as a 'red noise' response to the 'white noise' forcing by atmospheric disturbances. At one weather station, Papa (northeast Pacific), this stochastic theory can be applied to both salinity and temperature, explaining the relative redness of the SSS spectrum. Similar results hold for a model grid point adjacent to Papa, where the relationships between atmospheric energy and water fluxes and actual changes in SST and SSS are what is expected from local linear stochastic theory. At the other weather stations, this theory cannot adequately explain mixed-layer variability. Two oceanic processes must be taken into account: at Panulirus (near Bermuda), mososcale eddies enhance the observed variability at high frequencies. At Mike and India (North Atlantic), variations in SST and SSS advection, indicated by the coherence and equal persistence of SST and SSS anomalies, contribute to much of the low frequency variability in the model and observations. To achieve a global perspective, TOPEX altimeter data and model results are used to identify regions of the ocean where these mechanisms of variability are important. Where mesoscale eddies are as energetic as at Panulirus, indicated by the TOPEX global distribution of sea level variability, one would expect enhanced variability on short time scales. In regions exhibiting signatures of variability similar to Mike and India, variations in SST and SSS advection should dominate at low frequencies. According to the model, this mode of variability is found in the circumpolar ocean and the northern North Atlantic, where it is associated with the irregular oscillations of the model's thermohaline circulation. C1 PRINCETON UNIV,ATMOSPHER & OCEAN SCI PROGRAM,PRINCETON,NJ 08544. RI Hall, Alex/D-8175-2014 NR 25 TC 45 Z9 47 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD MAR PY 1997 VL 13 IS 3 BP 167 EP 180 DI 10.1007/s003820050158 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WT943 UT WOS:A1997WT94300001 ER PT J AU Levine, J AF Levine, J TI Why experimentalists mistrust computer modeling - And why they rely on it SO COMPUTERS IN PHYSICS LA English DT Editorial Material RP Levine, J (reprint author), UNIV COLORADO,NIST,DIV TIME & FREQUENCY,BOULDER,CO 80309, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0894-1866 J9 COMPUT PHYS JI Comput. Phys. PD MAR-APR PY 1997 VL 11 IS 2 BP 125 EP 125 PG 1 WC Computer Science, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Computer Science; Physics GA WR042 UT WOS:A1997WR04200002 ER PT J AU Reader, J AF Reader, J TI Transition arrays in atomic spectroscopy with a commercial spreadsheet program SO COMPUTERS IN PHYSICS LA English DT Article ID ENERGY-LEVELS; SPECTRUM AB In deducing the experimental energy levels of an atom from its observed spectral lines, a two-dimensional transition array showing all the predicted and identified electric-dipole transitions can be of gnat help. A system for using a commercial spreadsheet program to construct these arrays is described. Use of such a program facilitates the generation of large arrays with little computer coding. The basic principles should be applicable to other areas where it is desired to organize experimental and theoretical data in a two-dimensional array. (C) 1997 American Institute of Physics. RP Reader, J (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 6 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0894-1866 J9 COMPUT PHYS JI Comput. Phys. PD MAR-APR PY 1997 VL 11 IS 2 BP 190 EP 193 DI 10.1063/1.168597 PG 4 WC Computer Science, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Computer Science; Physics GA WR042 UT WOS:A1997WR04200018 ER PT J AU Incze, LS Siefert, DW Napp, JM AF Incze, LS Siefert, DW Napp, JM TI Mesozooplankton of Shelikof Strait, Alaska: Abundance and community composition SO CONTINENTAL SHELF RESEARCH LA English DT Article ID POLLOCK THERAGRA-CHALCOGRAMMA; OCEANIC SUBARCTIC PACIFIC; SOUTHEASTERN BERING SEA; YOUNG WALLEYE POLLOCK; GULF-OF-ALASKA; COASTAL CURRENT; WESTERN GULF; NEOCALANUS-PLUMCHRUS; LIFE-HISTORY; VERTICAL-DISTRIBUTION AB Zooplankton was sampled in Shelikof Strait and some of the surrounding shelf waters from March to October 1985, and then in Shelikof Strait during spring 1986-1989, using 150 and 333 mu m mesh nets. The median integrated abundance of copepods in spring was 1-2 orders of magnitude greater in the Strait (maximum depth >250 m) than over shallower, adjacent regions of continental shelf. Zooplankton fauna was a mixture of oceanic and continental shelf taxa, and among the copepods was strongly influenced by abundance of two deep-water species, Neocalanus plumchrus and Metridia pacifica. Seasonal development of the copepod community in Shelikof Strait followed similar patterns over the 5-year period. Biomass of copepods showed some large interannual differences related mostly to abundance of the oceanic taxa. Large interannual differences were found for some of the other zooplanktonic taxa as well, but there did not appear to be any correspondence between the patterns shown by these groups and those shown by the copepods. Although euphausiids were not quantitatively sampled, the taxonomic composition and relative abundance and seasonality of species within this group are reported. Copyright (C) 1996 Elsevier Science Ltd C1 NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98195. RP Incze, LS (reprint author), BIGELOW LAB OCEAN SCI,W BOOTHBAY HARBOR,ME 04575, USA. NR 64 TC 35 Z9 36 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0278-4343 J9 CONT SHELF RES JI Cont. Shelf Res. PD MAR PY 1997 VL 17 IS 3 BP 287 EP 305 DI 10.1016/S0278-4343(96)00036-2 PG 19 WC Oceanography SC Oceanography GA WB924 UT WOS:A1997WB92400004 ER PT J AU Wilson, WD Johns, WE AF Wilson, WD Johns, WE TI Velocity structure and transport in the Windward Islands Passages SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID NORTH BRAZIL CURRENT; FLORIDA CURRENT; CURRENT RETROFLECTION; ATLANTIC CIRCULATION; OCEAN; VARIABILITY AB During 1991-1994, repeated measurements of current structure and water mass properties were made in the major southern passages to the Caribbean Sea between Trinidad and Dominica. A total of 10 cruises were performed in different seasons, consisting primarily of serial station occupations in the Grenada, St Vincent, St Lucia, and Dominica Passages. This data set is by far the most comprehensive available in these passages and better determines the mean flow and range of variability than do previous studies. The flow structure in these passages is characterized by a strong and relatively stable inflow above the thermocline (approximately the upper 100 m), and a more highly variable flow regime within and below the thermocline. Typical near-surface inflow velocities in Grenada and St Vincent passages were 40-60 cm s(-1), with maximum observed currents of 90 cm s(-1). Frequently, counterflows were observed below this surface layer flowing out of the Caribbean, trapped to the southern side of the passages. This subsurface counterflow appeared to be strongest and most prevalent in Grenada Passage, where outflow speeds as large as 30 cm s(-1) were observed. As a result, the ensemble mean sections for the three southern passages exhibit a deep inflow concentrated in the northern and central parts of the passages, and weak outflow on the southern sides. The ensemble of measurements from this program indicate a mean transport of 9.5 +/- 3 x 10(6)m(3)s(-1) through the southern passages, with a range of variability from 3 to 17 x 10(6) m(3) s(-1). No clear annual cycle is apparent in the passage transports. Mean transports calculated for the individual passages were 4.7, 3.4, 0.9, and 0.5 x 10(6) m(3) s(-1), respectively, for Grenada, St Vincent, St Lucia, and Dominica Passages, decreasing monotonically northward and indicating that Grenada and St Vincent Passages largely dominate the inflow to the southern Caribbean. Consideration of this data set, historical data, Sverdrup theory and numerical model results suggests that very little of the mean inflow to the Caribbean through the southern passages can be attributed to wind-driven circulation, and that most of the transport (6-8 x 10(6) m(3) s(-1)) is derived from South Atlantic waters crossing the equator in the upper limb of the Atlantic thermohaline cell. The remainder of the upper ocean thermohaline transport likely follows a different route into the subtropical gyre, possibly flowing northward in the interior and entering the Caribbean through the more northern passages. C1 UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MIAMI,FL 33149. RP Wilson, WD (reprint author), NOAA,ATLANTIC OCEANOG & METEOROL LAB,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. NR 47 TC 32 Z9 33 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0967-0637 J9 DEEP-SEA RES PT I JI Deep-Sea Res. Part I-Oceanogr. Res. Pap. PD MAR PY 1997 VL 44 IS 3 BP 487 EP 520 DI 10.1016/S0967-0637(96)00113-6 PG 34 WC Oceanography SC Oceanography GA WV153 UT WOS:A1997WV15300008 ER PT J AU Barlow, J Clapham, PJ AF Barlow, J Clapham, PJ TI A new birth-interval approach to estimating demographic parameters of humpback whales SO ECOLOGY LA English DT Article DE birth intervals; birth rate; demography; fecundity; growth rate; humpback whale; Megaptera novaeangliae; modelling; population; survival ID MEGAPTERA-NOVAEANGLIAE; SEX-RATIO; MAINE; GULF AB A demographic model is developed based on interbirth intervals and is applied to estimate the population growth rate of humpback whales (Megaptera novaeangliae) in the Gulf of Maine. Fecundity rates in this model are based on the probabilities of giving birth at time t after a previous birth and on the probabilities of giving birth first at age x. Maximum likelihood methods are used to estimate these probabilities using sighting data collected for individually identified whales. Female survival rates are estimated from these same sighting data using a modified Jolly-Seber method. The youngest age at first parturition is 5 yr, the estimated mean birth interval is 2.38 yr (se = 0.10 yr), the estimated noncalf survival rate is 0.960 (se = 0.008), and the estimated calf survival rate is 0.875 (se = 0.047). The population growth rate (lambda) is estimated to be 1.065; its standard error is estimated as 0.012 using a Monte Carlo approach, which simulated sampling from a hypothetical population of whales. The simulation is also used to investigate the bias in estimating birth intervals by previous methods. The approach developed here is applicable to studies of other populations for which individual interbirth intervals can be measured. C1 CETACEAN RES PROGRAM,CTR COASTAL STUDIES,PROVINCETOWN,MA 02657. RP Barlow, J (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,POB 271,LA JOLLA,CA 92038, USA. NR 28 TC 74 Z9 86 U1 1 U2 26 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 0012-9658 J9 ECOLOGY JI Ecology PD MAR PY 1997 VL 78 IS 2 BP 535 EP 546 PG 12 WC Ecology SC Environmental Sciences & Ecology GA WN754 UT WOS:A1997WN75400018 ER PT J AU Beaver, B DeMunshi, R Heneghan, SP Whitacre, SD Neta, P AF Beaver, B DeMunshi, R Heneghan, SP Whitacre, SD Neta, P TI Model studies directed at the development of new thermal oxidative stability enhancing additives for future jet fuels SO ENERGY & FUELS LA English DT Article ID PEROXYL RADICALS; AROMATIC-AMINES; RATE CONSTANTS; DEGRADATION; RADIOLYSIS; IONS AB Thermal stressing of a Jet A fuel containing triphenylphosphine (TPP) as an additive results in a significant enhancement in thermal oxidative stability. Efforts to elucidate the mechanism(s) responsible for the observed thermal oxidative stability enhancement are reported, Data presented for the reaction of TPP with molecular oxygen show two pathways to be important. In particular, in nonpolar solvents and in the presence of BHT, the data. are consistent with TPP playing an oxygen scavenging role via operation of an electron-transfer-initiated-oxygenation chain mechanism. The significances of these findings to the potential development of a new generation of thermal oxidative stability enhancing additives is discussed. C1 UNIV DAYTON,RES INST,DAYTON,OH 45469. NIST,PHYS & CHEM POPERTIES DIV,GAITHERSBURG,MD 20899. RP Beaver, B (reprint author), DUQUESNE UNIV,DEPT CHEM & BIOCHEM,PITTSBURGH,PA 15282, USA. NR 24 TC 13 Z9 14 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD MAR-APR PY 1997 VL 11 IS 2 BP 396 EP 401 DI 10.1021/ef960192c PG 6 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA WP332 UT WOS:A1997WP33200024 ER PT J AU Boreman, J AF Boreman, J TI Sensitivity of North American sturgeons and paddlefish to fishing mortality SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article; Proceedings Paper CT International Conference on Sturgeon Biodiversity and Conservation CY JUL 28-30, 1994 CL AMER MUSEUM NAT HIST, NEW YORK, NY HO AMER MUSEUM NAT HIST DE reproductive potential; exploitation; endangered species; chondrosteans; eggs per recruit ID PALLID STURGEON; FISHES AB Sturgeons and paddlefish exhibit unusual combinations of morphology, habits, and life history characteristics, which make them highly vulnerable to impacts from human activities, particularly fisheries. Five North American sturgeons (shortnose, Gulf, pallid, Alabama, and green sturgeon) are listed as endangered or threatened by management authorities. Managers have instituted fishery closures for the three other species of North American sturgeons (Atlantic, white, and shovelnose) and paddlefish because of low stock abundance at some point in this century. Reproductive potential in four species I examined (Atlantic, white, and shortnose sturgeon, and paddlefish) is more sensitive to fishing mortality than it is for three other intensively-fished coastal species in North America: striped bass, winter flounder, and bluefish. The sturgeons and paddlefish are generally longer-lived than the three other coastal species, and also have an older age at full maturity, lower maximum fecundity values, and older ages at which 50% of the lifetime egg production is realized with no fishing mortality. RP Boreman, J (reprint author), UNIV MASSACHUSETTS,INST ENVIRONM,NOAA,COOPERAT MARINE EDUC & RES PROGRAM,POB 30820,AMHERST,MA 01003, USA. NR 22 TC 108 Z9 108 U1 4 U2 33 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD MAR PY 1997 VL 48 IS 1-4 BP 399 EP 406 DI 10.1023/A:1007345806559 PG 8 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA WX720 UT WOS:A1997WX72000029 ER PT J AU Cohen, A AF Cohen, A TI Sturgeon poaching and black market caviar: A case study SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article; Proceedings Paper CT International Conference on Sturgeon Biodiversity and Conservation CY JUL 28-30, 1994 CL AMER MUSEUM NAT HIST, NEW YORK, NY HO AMER MUSEUM NAT HIST DE Acipenser transmontanus; Columbia River; Lacey Act; beluga caviar; illegal harvesting; environmental crimes AB This paper documents a recent United States Federal prosecution of members of a poaching ring that sold caviar derived from illegally taken Columbia River white sturgeon, Acipenser transmontanus. Experts estimated that over 2000 adult sturgeon were killed in the process of illegally harvesting the more than 1500 kg of caviar involved in the case. Case studies of illegal activities related to exploitation of natural resources are rare. These crimes are difficult to discover and prosecute, for secrecy is essential, and by the time the facts are publicly available, irreparable environmental damage may have already been done. Sturgeons and paddle-fishes have long life spans but take many years to reach reproductive maturity; they reproduce infrequently and rely upon large, often urban rivers for their spawning migrations. These basic biological characteristics render these fishes especially susceptible to illegal exploitation, particularly when stocks have already been damaged by overfishing, dam construction or pollution (as has the Columbia River population of white sturgeon). Given the often exorbitant prices for sturgeon and paddlefish caviar, and the relative ease of capturing these fishes during their spawning migrations, persons may be tempted to circumvent state and federal regulations designed to protect acipenseriforms. Additionally, those involved in the distribution and sale of caviar can be motivated to fraudulently mislabel the product; for instance, in this case, white sturgeon caviar was marked as beluga caviar and sold at approximately five times the normal price of white sturgeon caviar. Despite the clear evidence of an environmental crime, the scale of the abuse, and the convictions, sentencing was light, a discouraging sign for those who hope to limit such destructive crimes in the future. RP Cohen, A (reprint author), NOAA,NATL MARINE FISHERIES SERV,US DEPT COMMERCE,OFF ENFORCEMENT,SEATTLE,WA 98115, USA. NR 6 TC 20 Z9 20 U1 1 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD MAR PY 1997 VL 48 IS 1-4 BP 423 EP 426 DI 10.1023/A:1007388803332 PG 4 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA WX720 UT WOS:A1997WX72000033 ER PT J AU Rozas, LP Minello, TJ AF Rozas, LP Minello, TJ TI Estimating densities of small fishes and decapod crustaceans in shallow estuarine habitats: A review of sampling design with focus on gear selection SO ESTUARIES LA English DT Review ID CRABS CALLINECTES-SAPIDUS; SEAGRASS-COVERED BANKS; BEAM-TRAWL CATCHES; BUOYANT POP NET; CAPE FEAR RIVER; SALT-MARSH; SOUTH-CAROLINA; NORTH-CAROLINA; PENAEUS-AZTECUS; FRESH-WATER AB Shallow estuarine habitats often support large populations of small nekton (fishes and decapod crustaceans), but unique characteristics of these habitats make sampling these nekton populations difficult. We discuss development of sampling designs and evaluate some commonly used devices for quantitatively sampling nekton populations. Important considerations of the sampling design include the size and number of samples, their distribution in time and space, and control of tide level. High, stable catch efficiency should be the most important gear characteristic considered when selecting a sampling device to quantify nekton densities. However, the most commonly used gears in studies of estuarine habitats (trawls and seines) have low, variable catch efficiency. Problems with consistently low catch efficiency can be corrected, but large unpredictable variations in this gear characteristic pose a much more difficult challenge. Study results may be biased if the variability in catch efficiency is related to the treatments or habitat characteristics being measured in the sampling design. Enclosure devices, such as throw traps and drop samplers, have fewer variables influencing catch efficiency than do towed nets (i.e., trawls and seines); and the catch efficiency of these enclosure samplers does not appear to vary substantially with habitat characteristics typical of shallow estuarine areas (e.g., presence of vegetation). The area enclosed by these samplers is often small, but increasing the sample number can generally compensate for this limitation. We recommend using enclosure samplers for estimating densities of small nekton in shallow estuarine habitats because these samplers provide the most reliable quantitative data, and the results of studies using these samplers should be comparable. Many kinds of enclosure samplers are now available, and specific requirements of a project will dictate which gear should be selected. RP Rozas, LP (reprint author), NATL OCEAN & ATMOSPHER ADM,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,4700 AVE U,GALVESTON,TX 77551, USA. NR 123 TC 224 Z9 235 U1 7 U2 50 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 SN 0160-8347 J9 ESTUARIES JI Estuaries PD MAR PY 1997 VL 20 IS 1 BP 199 EP 213 DI 10.2307/1352731 PG 15 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA WT784 UT WOS:A1997WT78400016 ER PT J AU Cerco, CF Seitzinger, SP AF Cerco, CF Seitzinger, SP TI Measured and modeled effects of benthic algae on eutrophication in Indian River Rehoboth Bay, Delaware SO ESTUARIES LA English DT Article ID COASTAL LAGOON ECOSYSTEM; NUTRIENT FLUX; INORGANIC NITROGEN; CHESAPEAKE BAY; FRESH-WATER; SEDIMENT; OXYGEN; MICROPHYTOBENTHOS; COMMUNITY; DYNAMICS AB A combination of field studies and mathematical modeling was used to examine the role of subtidal benthic algae in the eutrophication processes in two shallow estuarine systems. Field measurements indicated uptake by benthic algae retained ammonium and phosphate in the sediments when light at the sediment surface exceeded approximate to 150 mu E m(-2) s(-1). The measurements were used to calibrate a newly developed model of benthic algal activity. The benthic algal model was coupled with a hydrodynamic model, a eutrophication model, and a sediment diagenesis model. In the simulated ecosystem, benthic algae had a major influence in the intra-annual cycling of nitrogen and phosphorus. When nutrients were abundant in the water column (late winter and spring) they were transferred to the sediments through algal activity. Diagenesis released these nutrients to the water column in summer when nutrients were scarce. As a result of the nutrient transfer, annual primary production in the water column, in the presence of benthic algae, exceeded production in the absence of the algae. C1 RUTGERS STATE UNIV,INST MARINE & COASTAL SCI,NOAA,CMER PROGRAM,NEW BRUNSWICK,NJ 08903. RP Cerco, CF (reprint author), USA,ENGINEER WATERWAYS EXPT STN,3909 HALLS FERRY RD,VICKSBURG,MS 39180, USA. NR 53 TC 56 Z9 60 U1 2 U2 9 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 SN 0160-8347 J9 ESTUARIES JI Estuaries PD MAR PY 1997 VL 20 IS 1 BP 231 EP 248 DI 10.2307/1352733 PG 18 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA WT784 UT WOS:A1997WT78400018 ER PT J AU Hillery, BR Girard, JE Schantz, MM Wise, SA AF Hillery, BR Girard, JE Schantz, MM Wise, SA TI Characterization of three Aroclor mixtures using a new cyanobiphenyl stationary phase SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article ID POLYCHLORINATED BIPHENYL CONGENERS; ELECTRON-CAPTURE DETECTION; GAS-CHROMATOGRAPHY; TECHNICAL MIXTURES; MASS-SPECTROMETRY; CHLOROBIPHENYLS; COLUMNS; SAMPLES AB The retention characteristics of all 209 polychlorinated biphenyl (PCB) congeners were determined on a new p,p-cyanobiphenyl stationary phase using gas chromatography with electron capture detection (GC-ECD). Response factors were determined relative to decachlorobiphenyl, PCB 209. Several congeners that coelute on the phases routinely used for PCB analysis are separated on this phase, including the hexachlorobiphenyls 138, 163, and 164. The p,p-cyanobiphenyl stationary phase exhibits altered retention for planar congeners, such that the toxic coplanar PCBs 77, 126, and 169 are eluted free from interference. Of the 209 congeners, 61 were separated using the p,p-cyanobiphenyl phase in conjunction with GC-ECD. When analyzed by gas chromatography with mass selective detection (GC-MSD), the number of congeners determined increased to 133. Therefore GC-MSD was used with the p,p-cyanobiphenyl phase to characterize three PCB mixtures: Aroclor 1242, Aroclor 1254, and Aroclor 1260. C1 NIST,DIV ANALYT CHEM,GAITHERSBURG,MD 20899. AMERICAN UNIV,DEPT CHEM,WASHINGTON,DC 20016. NR 35 TC 12 Z9 12 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD MAR PY 1997 VL 357 IS 6 BP 723 EP 731 DI 10.1007/s002160050239 PG 9 WC Chemistry, Analytical SC Chemistry GA WQ869 UT WOS:A1997WQ86900027 ER PT J AU Kilb, D Ellis, M Gomberg, J Davis, S AF Kilb, D Ellis, M Gomberg, J Davis, S TI On the origin of diverse aftershock mechanisms following the 1989 Loma Prieta earthquake SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE aftershocks; Loma Prieta ID WHITTIER-NARROWS; CALIFORNIA; SEQUENCE; INVERSION; STRESS; FAULT; SLIP; TECTONICS; GEOMETRY; HISTORY AB We test the hypothesis that the origin of the diverse suite of aftershock mechanisms following the 1989 M7.1 Loma Prieta, California, earthquake is related to the post-main-shock static stress field. We use a 3-D boundary-element algorithm to calculate static stresses, combined with a Coulomb failure criterion to calculate conjugate failure planes at aftershock locations. The post-main-shock static stress field is taken as the sum of a pre-existing stress field and changes in stress due to the heterogeneous slip across the Loma Prieta rupture plane. The background stress field is assumed to be either a simple shear parallel to the regional trend of the San Andreas fault or approximately fault-normal compression. A suite of synthetic aftershock mechanisms from the conjugate failure planes is generated and quantitatively compared (allowing for uncertainties in both mechanism parameters and earthquake locations) to well-constrained mechanisms reported in the US Geological Survey Northern California Seismic Network catalogue. We also compare calculated rakes with those observed by resolving the calculated stress tensor onto observed focal mechanism nodal planes, assuming either plane to be a likely rupture plane. Various permutations of the assumed background stress field, frictional coefficients of aftershock fault planes, methods of comparisons, etc. explain between 52 and 92 per cent of the aftershock mechanisms. We can explain a similar proportion of mechanisms, however, by comparing a randomly reordered catalogue with the various suites of synthetic aftershocks. The inability to duplicate aftershock mechanisms reliably on a one-to-one basis is probably a function of the combined uncertainties in models of main-shock slip distribution, the background stress field, and aftershock locations. In particular, we show theoretically that any specific main-shock slip distribution and a reasonable background stress held are able to generate a highly variable suite of failure planes such that quite different aftershock mechanisms may be expected to occur within a kilometre or less of each other. This scale of variability is less than the probable location error of aftershock earthquakes in the Loma Prieta region. We successfully duplicate a measure of the variability in the mechanisms of the entire suite of aftershocks. If static stress changes are responsible for the generation of aftershock mechanisms, we are able to place quantitative constraints on the level of stress that must have existed in the upper crust prior to the Loma Prieta rupture. This stress level appears to be too low to generate the average slip across the main-shock rupture plane. Possible reasons for this result range from incorrect initial assumptions of homogeneity in the background stress field, friction and fault geometry to driving stresses that arise from deeper in the crust or upper mantle. Alternatively, aftershock focal mechanisms may be determined by processes other than, or in addition to, static stress changes, such as pore-pressure changes or dynamic stresses. C1 US GEOL SURVEY,MEMPHIS,TN. UNIV COLORADO,NGDC,NOAA,CIRES,BOULDER,CO 80309. RP Kilb, D (reprint author), UNIV MEMPHIS,CTR EARTHQUAKE RES & INFORMAT,MEMPHIS,TN 38152, USA. NR 48 TC 38 Z9 43 U1 0 U2 3 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD MAR PY 1997 VL 128 IS 3 BP 557 EP 570 DI 10.1111/j.1365-246X.1997.tb05318.x PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WL669 UT WOS:A1997WL66900005 ER PT J AU Carr, ME Kearns, EJ Rossby, HT AF Carr, ME Kearns, EJ Rossby, HT TI Isopycnal RAFOS floats as roving hydrographers in the North Atlantic Current region SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The properties measured by isopycnal floats can be compiled to provide hydrographic information about the sampled surfaces. The height and temperature of two specific volume anomaly surfaces reported by 84 RAFOS floats deployed in the North Atlantic Current (NAC) region are compared here with the climatological hydrographic database. The mean pathway of the NAC and other prominent features of the region are similar in float-derived and climatological surfaces. The most striking difference between floats and climatology, an extended trough in the NAC path at 44 degrees N in the float-derived surface, reflects the sampling time scales. The baroclinic transport of the NAC estimated from RAFOS floats using the observed climatological relationship between the potential energy anomaly and the height of the specific volume anomaly surfaces was 42 Sv at 42 degrees N and 24 Sv at 47 degrees N, in reasondble agreement with climatological estimates. C1 NATL DATA BUOY CTR,BAY ST LOUIS,MS 39529. UNIV RHODE ISL,GRAD SCH OCEANOG,NARRAGANSETT,RI 02882. RP Carr, ME (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 300-323,PASADENA,CA 91109, USA. NR 11 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 1 PY 1997 VL 24 IS 5 BP 551 EP 554 DI 10.1029/97GL00156 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WL742 UT WOS:A1997WL74200015 ER PT J AU Ramaswamy, V Chen, CT AF Ramaswamy, V Chen, CT TI Linear additivity of climate response for combined albedo and greenhouse perturbations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AEROSOLS; GASES AB Using an atmospheric general circulation model with fixed cloud amounts and microphysical properties, and coupled to a mixed-layer static ocean, we perform idealized experiments to inquire into the linear characteristics of the modeled climate system's mean response to simultaneous greenhouse and Northern Hemisphere midlatitude albedo perturbations, two forcings deemed to be important during the present times. The two forcings are chosen to be equal and opposite in the global, annual-mean such that a linear behavior would be expected to lead to a complete offset of the global, annual-mean surface temperature change, which is indeed obtained. The monthly and annual zonal-mean surface temperature, and the annual zonal-mean precipitation responses to the combined forcings, also are reasonably similar to the sum of the responses to the individual forcings. The albedo forcing case casts a distinct signature on the circulation and precipitation changes in the northern and southern equatorial regions, which is absent for the greenhouse forcing case. The combined simulation yields a result similar to that for the albedo forcing case, one that is consistent with linear additive expectations. C1 NATL TAIWAN NORMAL UNIV,DEPT EARTH SCI,TAIPEI 117,TAIWAN. RP Ramaswamy, V (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,POB 308,PRINCETON,NJ 08542, USA. NR 12 TC 38 Z9 38 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 1 PY 1997 VL 24 IS 5 BP 567 EP 570 DI 10.1029/97GL00248 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WL742 UT WOS:A1997WL74200019 ER PT J AU Tans, PP AF Tans, PP TI A note on isotopic ratios and the global atmospheric methane budget SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID CARBON; GASES; MODEL AB The temporal and spatial behavior of the isotopic ratio of atmospheric methane can be quite different from that of total methane. Changes in the isotopic ratio are the result of shifts between isotopically different methane sources, as well as changes in the total amount of methane into which methane from sources is being diluted. As a result, the timescale for isotopic changes is often considerably longer than for changes in total methane, and large-scale spatial gradients of the isotopic ratio adjust very slowly to a new source configuration, in sharp contrast to total methane. RP Tans, PP (reprint author), NOAA,CLIMATE MONITORING & DIAGNOST LAB,MAIL CODE R-E-CG1,325 BROADWAY,BOULDER,CO 80303, USA. NR 11 TC 49 Z9 49 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD MAR PY 1997 VL 11 IS 1 BP 77 EP 81 DI 10.1029/96GB03940 PG 5 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA WL541 UT WOS:A1997WL54100005 ER PT J AU Voas, J AF Voas, J TI How assertions can increase test effectiveness SO IEEE SOFTWARE LA English DT Article RP Voas, J (reprint author), NATL INST STAND & TECHNOL,BOULDER,CO 80303, USA. NR 0 TC 8 Z9 8 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 SN 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD MAR-APR PY 1997 VL 14 IS 2 BP 118 EP & DI 10.1109/52.582981 PG 3 WC Computer Science, Software Engineering SC Computer Science GA WM371 UT WOS:A1997WM37100024 ER PT J AU Grody, NC Basist, AN AF Grody, NC Basist, AN TI Interpretation of SSM/I measurements over Greenland SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID ICE-SHEET; MICROWAVE MEASUREMENTS; SNOW-COVER; MELT; SMMR AB Multispectral brightness temperature (T-B) measurements over Greenland are obtained from the Special Sensor Microwave Imager (SSM/I), which are flown aboard the DMSP satellites, This paper examines the different spectral characteristics over Greenland throughout the year, Although snow covers the vast majority of Greenland, the southern regions rarely exhibit the spectral characteristics associated with snowcover (i.e., T-B decreases at higher frequencies), In fact, the SSM/I polarization and frequency measurements over southern Greenland are more indicative of water than a snow-covered surface (i.e., T-B increases at higher frequencies), A simplified physical model is developed to help explain the anomalous measurements over southern Greenland, Model results indicate that high frequency radiation is mainly scattered by snow grains residing above the subsurface ice layers, whereas low frequency radiation is scattered throughout a much greater depth, Since low frequencies are scattered throughout a greater volume, they are depressed relative to high frequencies, and the typical snowcover signature is absent. C1 NOAA,CLIMATE ANAL CTR,WASHINGTON,DC 20233. RP Grody, NC (reprint author), NOAA,SATELLITE RES LAB,WASHINGTON,DC 20233, USA. NR 18 TC 19 Z9 21 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 1997 VL 35 IS 2 BP 360 EP 366 DI 10.1109/36.563275 PG 7 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA WN531 UT WOS:A1997WN53100016 ER PT J AU Jacobson, MD Nunnelee, WM AF Jacobson, MD Nunnelee, WM TI Design and performance of a spinning flat reflector for millimeter-wave radiometry SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID MICROWAVE RADIOMETER; LIQUID; WATER; VAPOR AB Two collocated millimeter-wave radiometers were operated at the Platteville, Colorado, site from January through March 1994. These radiometers are identical, with the exception that one radiometer uses a spinning flat reflector, while the other one uses a fixed flat reflector, The spinning reflector was designed to shed precipitation particles, thus improving the radiometer's performance during precipitating conditions. C1 NOAA,NATL WEATHER SERV,KANSAS CITY,MO 64106. RP Jacobson, MD (reprint author), NOAA,ENVIRONM TECHNOL LAB,BOULDER,CO 80303, USA. NR 7 TC 4 Z9 4 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 1997 VL 35 IS 2 BP 464 EP 466 DI 10.1109/36.563285 PG 3 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA WN531 UT WOS:A1997WN53100026 ER PT J AU Walls, FL FerrePikal, ES Jefferts, SR AF Walls, FL FerrePikal, ES Jefferts, SR TI Origin of 1/fPM and AM noise in bipolar junction transistor amplifiers SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article AB In this paper we report the results of extensive research on phase modulation (PM) and amplitude modulation (AM) noise in linear bipolar junction transistor (BJT) amplifiers. BJT amplifiers exhibit 1/f PM and AM noise about a carrier signal that is much larger than the amplifiers thermal noise at those frequencies in the absence of the carrier signal. Our work shows that the 1/f PM noise of a BJT based amplifier is accompanied by 1/f AM noise which can be higher, lower, or nearly equal, depending on the circuit implementation. The 1/f AM and PM noise in BJTs is primarily the result of 1/f fluctuations in transistor current, transistor capacitance, circuit supply voltages, circuit impedances, and circuit configuration. We discuss the theory and present experimental data in reference to common emitter amplifiers, but the analysis can be applied to other configurations as well. This study provides the functional dependence of 1/f AM and PM noise on transistor parameters, circuit parameters, and signal frequency, thereby laying the groundwork for a comprehensive theory of 1/f AM and PM noise in BJT amplifiers. We show that in many cases the 1/f PM and AM noise can be reduced below the thermal noise of the amplifier. RP Walls, FL (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 10 TC 49 Z9 49 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAR PY 1997 VL 44 IS 2 BP 326 EP 334 DI 10.1109/58.585117 PG 9 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA WR981 UT WOS:A1997WR98100009 PM 18244130 ER PT J AU FerrePikal, ES Walls, FL Nelson, CW AF FerrePikal, ES Walls, FL Nelson, CW TI Guidelines for designing BJT amplifiers with low 1/f AM and PM noise SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article AB In this paper we discuss guidelines for designing linear bipolar junction transistor amplifiers with low 1/f amplitude modulation (AM) and phase modulation (PM) noise. These guidelines are derived from a new theory that relates AM and PM noise to transconductance fluctuations, junction capacitance fluctuations, and circuit architecture. We analyse the noise equations of each process for a common emitter (CE) amplifier and use the results to suggest amplifier designs that minimize the 1/f noise while providing other required attributes such as high gain. Although we use a CE amplifier as an example, the procedure applies to other configurations as well. Experimental noise results for several amplifier configurations are presented. RP FerrePikal, ES (reprint author), NATL INST STAND & TECHNOL, 325 BROADWAY, BOULDER, CO 80303 USA. NR 8 TC 23 Z9 23 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 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAR PY 1997 VL 44 IS 2 BP 335 EP 343 DI 10.1109/58.585118 PG 9 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA WR981 UT WOS:A1997WR98100010 PM 18244131 ER PT J AU Liu, HC Hong, TH Herman, M Chellappa, R AF Liu, HC Hong, TH Herman, M Chellappa, R TI A general motion model and spatio-temporal filters for computing optical flow SO INTERNATIONAL JOURNAL OF COMPUTER VISION LA English DT Article DE Hermite polynomial; motion estimation; evaluation ID RECOVERING 3-D MOTION; INHERENT AMBIGUITIES; IMAGE VELOCITY; FIELD; SEGMENTATION; OPTIMIZATION; COMPUTATION; PERCEPTION AB Traditional optical flow algorithms assume local image translational motion and apply simple image filtering techniques. Recent studies have taken two separate approaches toward improving the accuracy of computed flow: the application of spatio-temporal filtering schemes and the use of advanced motion models such as the affine model. Each has achieved some improvement over traditional algorithms in specialized situations but the computation of accurate optical flow for general motion has been elusive. In this paper, we exploit the interdependency between these two approaches and propose a unified approach. The general motion model we adopt characterizes arbitrary 3-D steady motion. Under perspective projection, we derive an image motion equation that describes the spatio-temporal relation of gray-scale intensity in an image sequence, thus making the utilization of 3-D filtering possible. However, to accommodate this motion model, we need to extend the filter design to derive additional motion constraint equations. Using Hermite polynomials, we design differentiation filters, whose orthogonality and Gaussian derivative properties insure numerical stability; a recursive relation facilitates application of the general nonlinear motion model while separability promotes efficiency. The resulting algorithm produces accurate optical flow and other useful motion parameters. It is evaluated quantitatively using the scheme established by Barren et al. (1994) and qualitatively with real images. C1 NIST, DIV INTELLIGENT SYST, GAITHERSBURG, MD 20899 USA. UNIV MARYLAND, CTR AUTOMAT RES, DEPT ELECT ENGN, COLLEGE PK, MD 20742 USA. NR 59 TC 31 Z9 33 U1 6 U2 8 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0920-5691 EI 1573-1405 J9 INT J COMPUT VISION JI Int. J. Comput. Vis. PD MAR PY 1997 VL 22 IS 2 BP 141 EP 172 DI 10.1023/A:1007988028861 PG 32 WC Computer Science, Artificial Intelligence SC Computer Science GA XD967 UT WOS:A1997XD96700003 ER PT J AU Yang, JC Vazquez, I Boyer, CI Huber, ML Weber, L AF Yang, JC Vazquez, I Boyer, CI Huber, ML Weber, L TI Measured and predicted thermodynamic properties of selected halon alternative nitrogen mixtures SO INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID LA English DT Article DE experimental methods; corresponding states model; halon alternatives; industrial applications ID REFRIGERANTS AB Experimental measurements of selected thermodynamic properties of alternative agent/ nitrogen mixtures were performed. The selected alternatives were HFC-227ea (C3HF7), CF3I, FC-218 (C3F8), and HFC-125 (C2HF5); CF3Br was also included as a reference, A thermodynamic model based on an extended corresponding states principle was used. The model predictions were generally found to be within 10% or less of the experimental measurements. The model can be used as a computational teal for designers of fire extinguishers to obtain pressure-temperature relationships for selected halon alternative/nitrogen mixtures. Published by Elsevier Science Ltd and IIR. C1 NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,BOULDER,CO 80303. RP Yang, JC (reprint author), NIST,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899, USA. NR 21 TC 5 Z9 8 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0140-7007 J9 INT J REFRIG JI Int. J. Refrig.-Rev. Int. Froid PD MAR PY 1997 VL 20 IS 2 BP 96 EP 105 DI 10.1016/S0140-7007(96)00070-9 PG 10 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA WZ882 UT WOS:A1997WZ88200004 ER PT J AU Alapaty, K Pleim, JE Raman, S Niyogi, DS Byun, DW AF Alapaty, K Pleim, JE Raman, S Niyogi, DS Byun, DW TI Simulation of atmospheric boundary layer processes using local- and nonlocal-closure schemes SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID MODEL; PARAMETERIZATION; FLUX AB A soil-vegetation-atmospheric boundary layer model was developed to study the performance of two local-closure and two nonlocal-closure boundary layer mixing schemes for use in meteorological and air quality simulation models. Full interaction between the surface and atmosphere is achieved by representing surface characteristics and associated processes using a prognostic soil-vegetation scheme and atmospheric boundary layer schemes. There are 30 layers in the lowest 3 km of the model with a high resolution near the surface, The four boundary layer schemes are tested by simulating atmospheric boundary layer structures over densely and sparsely vegetated regions using the observational data from the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE) and from Wangara. Simulation results indicate that the near-surface turbulent fluxes predicted by the four boundary layer schemes differ from each other, even though the formulation used to represent the surface-layer processes is the same. These differences arise from the differing ways of representing subgrid-scale vertical mixing processes. Results also indicate that the vertical profiles of predicted parameters (i.e., temperature, mixing ratio, and horizontal winds) from the four mixed-layer schemes differ from each other, particularly during the daytime growth of the mixed layer. During the evening hours, after the mixed layer has reached its maximum depth, the differences among these respective predicted variables are found to be insignificant. There were some general features that were associated with each of the schemes in all of the simulations. Compared with observations, in all of the cases the simulated maximum depths of the boundary layer for each scheme were consistently either lower or higher, superadiabatic lapse rates were consistently either stronger or weaker, and the intensity of the vertical mixing was either stronger or weaker. Also, throughout the simulation period in all case studies, most of the differences in the predicted parameters are present in the surface layer and near the top of the mixed layer. C1 NATL OCEAN & ATMOSPHER ADM,AIR RESOURCES LAB,RES TRIANGLE PK,NC. N CAROLINA STATE UNIV,DEPT MARINE EARTH & ATMOSPHER SCI,RALEIGH,NC 27695. RP Alapaty, K (reprint author), MCNC N CAROLINA SUPERCOMP CTR,ENVIRONM PROGRAMS,POB 12889,3021 CORNWALLIS RD,RES TRIANGLE PK,NC 27709, USA. RI Pleim, Jonathan Pleim/C-1331-2017 OI Pleim, Jonathan Pleim/0000-0001-6190-6082 NR 26 TC 53 Z9 53 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAR PY 1997 VL 36 IS 3 BP 214 EP 233 DI 10.1175/1520-0450(1997)036<0214:SOABLP>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WM250 UT WOS:A1997WM25000003 ER PT J AU Archer, DG AF Archer, DG TI Enthalpy increment measurements for NaCl(cr) and KBr(cr) from 4.5 K to 350 K. Thermodynamic properties of the NaCl+H2O system .3. SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID INTERNATIONAL TEMPERATURE SCALE; SYNTHETIC SAPPHIRE ALPHA-AL2O3; STANDARD REFERENCE MATERIAL; COPPER; HEAT AB Enthalpy increments for sodium chloride and potassium bromide were measured from 4.5 K to 350 K with an adiabatic calorimeter. These measurements were combined with other selected values from the literature to generate models that represented the thermal properties of crystalline sodium chloride and potassium bromide to the melting points. The entropy, enthalpy relative to 0 K, and the heat capacity of sodium chloride and potassium bromide were calculated from these models. The new measurements and models were compared to previous measurements of the thermodynamic properties of crystalline sodium chloride and potassium bromide. Additionally, the equation for the thermodynamic properties of copper given by Martin (Rev. Sci. Instrum. 1987, 58, 639), which is useful for calibration of calorimeters for temperatures below 310 K, was adjusted for the difference of the International Temperature Scale of 1990 from the International Practical Temperature Scale of 1968. RP Archer, DG (reprint author), NIST,CHEM SCI & TECHNOL LAB,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899, USA. NR 30 TC 9 Z9 9 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAR-APR PY 1997 VL 42 IS 2 BP 281 EP 292 DI 10.1021/je960224q PG 12 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA WM813 UT WOS:A1997WM81300011 ER PT J AU Ripple, D Defibaugh, D AF Ripple, D Defibaugh, D TI Viscosity of the saturated liquid phase of three fluorinated ethanes: R152a, R143a, and R125 SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID PENTAFLUOROETHANE R125; VISCOMETER AB Data are reported for the viscosity of three saturated liquids over a temperature range from 255 K to 323 K. The liquids studied are the fluorinated compounds 1,1-difluoroethane (R152a), 1,1,1-trifluoroethane (R143a), and pentafluoroethane (R125). A capillary viscometer constructed of stainless steel and sapphire was used to obtain the data. The viscosity measurements have an expanded uncertainty of 2.4%. A free volume model of viscosity was used to correlate the data. C1 NIST,TECHNOL ADM,DEPT COMMERCE,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. RP Ripple, D (reprint author), NIST,TECHNOL ADM,DEPT COMMERCE,PROC MEASUREMENTS DIV,GAITHERSBURG,MD 20899, USA. NR 25 TC 17 Z9 18 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAR-APR PY 1997 VL 42 IS 2 BP 360 EP 364 DI 10.1021/je960284w PG 5 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA WM813 UT WOS:A1997WM81300027 ER PT J AU Given, JA Hubbard, JB Douglas, JF AF Given, JA Hubbard, JB Douglas, JF TI A first-passage algorithm for the hydrodynamic friction and diffusion-limited reaction rate of macromolecules SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BROWNIAN DYNAMICS SIMULATIONS; SPHERICAL-PARTICLES; FIBROUS MATRICES; CAPACITANCE; POLYHEDRA; SURFACE AB Many important properties of a macromolecule can be expressed in terms of averages over the trajectories of diffusing particles that,begin in the medium surrounding the molecule and terminate at its surface. These properties include its translational hydrodynamic friction coefficient and the Smoluchowski rate constant for diffusion-limited reactions. In this paper we introduce a first-passage algorithm (FPA) for calculating such quantities. This algorithm uses certain exact Green's functions, or propagators, for the Laplace equation to eliminate the need to construct explicitly those portions of a diffusing particle's trajectory that are not near an absorbing object. The algorithm is especially efficient for studying objects that contain large voids or have very irregular surfaces, such as macromolecules. Diffusion algorithms were previously shown to give accurate results for the quantities we study. In this paper, we show that rst-passage methods make these algorithms more accurate and efficient. In future work, we expect to present systematic results for the properties of globular proteins. (C) 1997 American Institute of Physics. C1 NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. RP Given, JA (reprint author), CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850, USA. NR 57 TC 38 Z9 38 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 1 PY 1997 VL 106 IS 9 BP 3761 EP 3771 DI 10.1063/1.473428 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WJ575 UT WOS:A1997WJ57500037 ER PT J AU Higgins, RW Yao, Y Yarosh, ES Janowiak, JE Mo, KC AF Higgins, RW Yao, Y Yarosh, ES Janowiak, JE Mo, KC TI Influence of the Great Plains low-level jet on summertime precipitation and moisture transport over the central United States SO JOURNAL OF CLIMATE LA English DT Article ID DIURNAL-VARIATIONS; SLOPING TERRAIN; SYSTEM; FLOODS AB The influence of the Great Plains low-lever jet (LLJ) on summertime precipitation and moisture transport over the central United States is examined in observations and in assimilated datasets recently produced by the NCEP/NCAR and the NASA/DAO. Intercomparisons between the assimilated datasets and comparisons with station observations of precipitation, winds, and specific humidity are used to evaluate the limitations of the assimilated products for studying the diurnal cycle of rainfall and the Great Plains LLJ. The winds from the reanalyses are used to diagnose the impact of the LLJ on observed nocturnal precipitation and moisture transport over a multisummer (JJA 1985-89) period. The impact of the LLJ on the overall inoisture budget of the central United States is also examined. An inspection of the diurnal cycle of precipitation in gridded hourly station observations for 1963-93 reveals a well-defined nocturnal maximum over the Great Plains region during the spring and summer months consistent with earlier observational studies. During summer in excess of 25% more precipitation falls during the nighttime hours than during the daytime hours over a large portion of the Great Plains, with a commensurate decrease in the percentage amount of nocturnal precipitation along the Gulf Coast Inspection of the nighttime precipitation by month shows that the maximum in precipitation along the Gulf Coast slowly shifts northward from the lower Mississippi Valley to the upper Midwest during the late spring and summer months and then back again during the fall. Both reanalyses produce a Great Plains LLJ with a structure, diurnal cycle, and frequency of occurrence that compares favorably to hourly wind profiler data. Composites of observed nighttime rainfall during LLJ events show a fundamentally different pattern in the distribution of precipitation compared to nonjet events. Overall, LLJ events are associated with enhanced precipitation over the north central United States and Great Plains and decreased precipitation along the Gulf Coast and East Coast; nonjet events are associated with much weaker anomalies that are generally in the opposite:sense. Inspection of the LLJ composites for each month shows a gradual shift of the region of enhanced precipitation from the northern tier of states toward the south and east in a manner consistent with the anomalous moisture transport. LLJ-related precipitation is found to be associated most closely with the strongest, least frequent LLJ events. The moisture transport in the reanalyses compares favorably to radiosonde data, although Significant regional differences exist, particularly along the Gulf Coast during summer. The diurnal cycle of the low-level moisture transport is well reserved in the reanalyses with the largest and most extensive anomalies being those associated with the nocturnal inland flow of the Great Plains LLJ. Examination of the impact of the LLJ on the:nighttime moisture transport shows a coherent evolution from May to August with a gradual increase in the anomalous westerly transport over the southeastern United States, consistent with the evolution of the precipitation patterns. The impact of the LLJ on the overall moisture budget during summer is considerable with low-level inflow from the Gulf of Mexico increasing by more than 45%, on average, over nocturnal mean values. C1 RES & DATA SYST CORP,GREENBELT,MD. RP Higgins, RW (reprint author), NOAA,NATL WEATHER SERV,NCEP,ANAL BRANCH,CLIMATE PREDICT CTR,WASHINGTON,DC 20233, USA. NR 41 TC 195 Z9 200 U1 4 U2 27 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAR PY 1997 VL 10 IS 3 BP 481 EP 507 DI 10.1175/1520-0442(1997)010<0481:IOTGPL>2.0.CO;2 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WM904 UT WOS:A1997WM90400009 ER PT J AU Goodberlet, MA Swift, CT Kiley, KP Miller, JL Zaitzeff, JB AF Goodberlet, MA Swift, CT Kiley, KP Miller, JL Zaitzeff, JB TI Microwave remote sensing of coastal zone salinity SO JOURNAL OF COASTAL RESEARCH LA English DT Article DE coastal salinity; coastal ocean temperature; coastal environments; littoral zone AB An operational airborne salinity remote sensing system is now available for coastal and estuarine studies with an accuracy of 1 ppt at 100 m spatial resolution. The system can perform area mapping at a rate of 100 km(2)/hr from low altitude light aircraft. Called the Scanning Low-Frequency Microwave Radiometer (SLFMR), the system is designed to operate from a small single-engine aircraft. The system is composed of an 8-beam 1.4 GHz microwave radiometer, a a-channel infrared radiometer, a Global Positioning Satellite (GPS) receiver for geolocation of the measurements and integral computer control. Working closely with personnel at the Virginia Institute of Marine Science (VIMS), the SLFMR was fitted to the VIMS U6-A DeHavilland Beaver aircraft. The first test flights of the SLFMR were completed in August 1993 over the Chesapeake Bay and coincided with extensive boat-based monitoring missions conducted by VIMS and Old Dominion University. Due to extensive Radio Frequency Interference (RFI) the 1993 test was not totally successful. The system was subsequently re-flown in 1994 over the Chesapeake Bay in a more friendly RFI environment. In this case, successful remote sensing measurements were made, which compared favorably with in situ data collected by VIMS. A final flight was conducted over Delaware Bay in an even more friendly RFI environment, and the data compared favorably with historical data compiled from ship surveys. C1 UNIV MASSACHUSETTS,AMHERST,MA 01003. COLL WILLIAM & MARY,SCH MARINE SCI,GLOUCESTER POINT,VA 23062. OLD DOMINION UNIV,CTR COASTAL PHYS OCEANOG,NORFOLK,VA 23529. NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,WASHINGTON,DC. RP Goodberlet, MA (reprint author), USN,RES LAB,CODE 7332,BAY ST LOUIS,MS 39529, USA. NR 12 TC 15 Z9 17 U1 0 U2 1 PU COASTAL EDUCATION & RESEARCH FOUNDATION PI LAWRENCE PA 810 EAST 10TH STREET, LAWRENCE, KS 66044 SN 0749-0208 J9 J COASTAL RES JI J. Coast. Res. PD SPR PY 1997 VL 13 IS 2 BP 363 EP 372 PG 10 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA WW936 UT WOS:A1997WW93600008 ER PT J AU Vogel, GL Mao, Y Carey, CM Chow, LC AF Vogel, GL Mao, Y Carey, CM Chow, LC TI Increased overnight fluoride concentrations in saliva, plaque, and plaque fluid after a novel two-solution rinse SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE fluoride; rinse; plaque; plaque-fluid; saliva ID CALCIUM-FLUORIDE; ENAMEL; INVITRO; DEMINERALIZATION; PHOSPHATE; RETENTION; NAF AB Recent studies showed that salivary, plaque-fluid, and whole-plaque fluoride were significantly higher 120 min after subjects rinsed with a novel two-solution rinse than after they rinsed with a NaF rinse of the same fluoride concentration. In this study, the persistence of these increases was investigated overnight, a period of time that is more clinically relevant. improved analytical techniques for the ultramicro determination of whole-plaque and plaque-fluid fluoride from the same sample are also described. Thirteen subjects abstained from toothbrushing for 48 hrs and rinsed for 1 min with a 12 mmol/L (228 ppm) NaF or the two-solution rinse before bedtime. Samples were then collected the following morning before breakfast: (1) Saliva samples were either clarified by centrifugation or acid-extracted with 1 mol/L HClO4; and (2) single-site molar plaque samples were centrifuged to obtain plaque fluid and/or extracted with 1 mol/L HClO4. Results showed that, compared with NaF, the two-solution rinse produced significantly higher fluoride concentrations in all samples: The concentration of fluoride in whole plaque and whole saliva following the new rinse exceeded concentrations found after the NaF rinse by factors of three and four, respectively, while in plaque fluid, the two-solution rinse produced about a two-fold increase over NaF values, which were near baseline levels. This increase, however, was only about 20% in centrifuged saliva. The increases in saliva and especially in plaque-fluid fluoride after the two-solution rinse indicate a greater remineralization potential, while the enhanced fluoride reservoirs found in plaque overnight after this rinse constitute a reserve that may release fluoride into the plaque fluid over an extended period of time. RP Vogel, GL (reprint author), NIST,AMER DENT ASSOC HLTH FDN,PAFFENBARGER RES CTR,ROOM A153,BLDG 224,GAITHERSBURG,MD 20899, USA. FU NIDCR NIH HHS [DE05354, DE10840, DE10851] NR 28 TC 36 Z9 39 U1 1 U2 5 PU AMER ASSOC DENTAL RESEARCH PI ALEXANDRIA PA 1619 DUKE ST, ALEXANDRIA, VA 22314 SN 0022-0345 J9 J DENT RES JI J. Dent. Res. PD MAR PY 1997 VL 76 IS 3 BP 761 EP 767 PG 7 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA WU193 UT WOS:A1997WU19300008 PM 9109825 ER PT J AU Gardner, JA Rao, MV Tian, YL Holland, OW Roth, EG Chi, PH Ahmad, I AF Gardner, JA Rao, MV Tian, YL Holland, OW Roth, EG Chi, PH Ahmad, I TI Rapid thermal annealing of ion implanted 6H-SIC by microwave processing SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 38th Electronic Materials Conference (EMC) CY JUN 26-28, 1996 CL UNIV OF CALIF AT SANTA BARBARA, SANTA BARBARA, CA HO UNIV OF CALIF AT SANTA BARBARA DE implantation; microwave annealing; rapid thermal processing; silicon carbide AB Rapid thermal processing utilizing microwave energy has been used to anneal N, P, and Al ion-implanted 6H-SiC. The microwaves raise the temperature of the sample at a rate of 200 degrees C/min vs 10 degrees C/min for conventional ceramic furnace annealing. Samples were annealed in the temperature range of 1400-1700 degrees C for 2-10 min. The implanted/annealed samples were characterized using van der Pauw Hall, Rutherford backscattering, and secondary ion mass spectrometry. For a given annealing temperature, the characteristics of the microwave annealed material are similar to those of conventional furnace anneals despite the difference in cycle time. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NIST,GAITHERSBURG,MD 20899. FM TECHNOL,FAIRFAX,VA 22032. RP Gardner, JA (reprint author), GEORGE MASON UNIV,DEPT ELECT & COMP ENGN,FAIRFAX,VA 22030, USA. NR 17 TC 19 Z9 20 U1 0 U2 2 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAR PY 1997 VL 26 IS 3 BP 144 EP 150 DI 10.1007/s11664-997-0141-5 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA WN137 UT WOS:A1997WN13700009 ER PT J AU Edwards, A Rao, MV Molnar, B Wickenden, AE Holland, OW Chi, PH AF Edwards, A Rao, MV Molnar, B Wickenden, AE Holland, OW Chi, PH TI Ion implantation doping of OMCVD grown GaN SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 38th Electronic Materials Conference (EMC) CY JUN 26-28, 1996 CL UNIV OF CALIF AT SANTA BARBARA, SANTA BARBARA, CA HO UNIV OF CALIF AT SANTA BARBARA DE annealing; gallium nitride; ion implantation; Rutherford back scattering ID MOLECULAR-BEAM EPITAXY; THERMAL-STABILITY; GALLIUM NITRIDE; FILMS; DIFFUSION; DOPANTS; INP; MG AB Doping by ion implantation using Si, O, Mg, and Ca has been studied in single crystal semi-insulating and n-type GaN grown on a-sapphire substrates. The nand p-type dopants used in this study are Si and O; Mg and Ca, respectively. Room temperature activation of Si and O donors has been achieved after 1150 degrees C annealing for 120 s. The activation of Mg and Ca accepters is too low to measure at both room temperature and 300 degrees C. Using higher doses to achieve a measurable p-type conduction increases the amount of damage created by the implantation. Rutherford back scattering measurements on this material indicate that the damage is still present even after the maximum possible heat treatment. Secondary ion mass spectrometry measurements have indicated a redistribution in the measured profiles of Mg due to annealing. C1 USN,RES LAB,WASHINGTON,DC 20375. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NIST,GAITHERSBURG,MD 20899. RP Edwards, A (reprint author), GEORGE MASON UNIV,DEPT ELECT & COMP ENGN,FAIRFAX,VA 22030, USA. NR 34 TC 12 Z9 12 U1 1 U2 9 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAR PY 1997 VL 26 IS 3 BP 334 EP 339 DI 10.1007/s11664-997-0174-9 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA WN137 UT WOS:A1997WN13700042 ER PT J AU Clauer, CR Ridley, AJ Sitar, RJ Singer, HJ Rodger, AS FriisChristensen, E Papitashvili, VO AF Clauer, CR Ridley, AJ Sitar, RJ Singer, HJ Rodger, AS FriisChristensen, E Papitashvili, VO TI Field line resonant pulsations associated with a strong dayside ionospheric shear convection flow reversal SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID LATITUDE BOUNDARY-LAYER; ELF-VLF EMISSIONS; PLASMA SHEET; ULF WAVES; MAGNETOSPHERE; GENERATION; CURRENTS AB We discuss a set of coordinated observations from the arrays of Greenland ground magnetometers, Sondrestrom incoherent scatter radar, and the DMSP, GOES 7, and IMP 8 satellites during 1000-1400 UT on August 4, 1991. The work presented here follows work presented by Clauer and Ridley [1995]. In the previous work we show that this particular interval is characterized by a large positive interplanetary magnetic field (IMF) B-y and near-zero IMF B-z components. Associated with these conditions is a very strong ionospheric convection shear reversal boundary in the dayside noon and prenoon sector in the northern hemisphere. The convection reversal boundary is observed to be very dynamic, showing wave-like displacements of several degrees in invariant latitude with a tailward phase propagation. These variations are associated with magnetic pulsations with a period of about 34 min. We have suggested that these waves are produced by a Kelvin-Helmholtz instability at the shear convection reversal boundary. We present here a more detailed analysis of the magnetic variations from the Greenland arrays of magnetometers. Our new findings show that equatorward of the convection reversal boundary there is power in the pulsation spectra in bands with periods of about 34, 17, 12, and 8 min. Examination of the northward component of the pulsations along a meridional chain of stations ranging from 76.23 degrees to 66.86 degrees invariant latitude shows high coherence between stations and a change in relative phase of about 160 degrees over the observed latitude range for the 8-min. pulsations. These observations are consistent with the expected signature of a field line resonance. We suggest that the source of the resonance is the disturbance generated at the shear convection reversal boundary which then produces resonances on nearby equatorward closed field lines. In this case we suggest that the source is the Kelvin-Helmholtz wave established at the east-west convection shear which develops near local noon and prenoon regions during large IMF B-y positive conditions. This is possibly the first observation of the field line resonance associated with such a source. C1 UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,ANN ARBOR,MI 48109. UNIV MICHIGAN,DEPT PHYS,ANN ARBOR,MI 48109. NOAA,SPACE ENVIRONM CTR,BOULDER,CO. BRITISH ANTARCTIC SURVEY,CAMBRIDGE,ENGLAND. DANISH INST FUNDAMENTAL METROL,COPENHAGEN,DENMARK. RP Clauer, CR (reprint author), UNIV MICHIGAN,SPACE PHYS RES LAB,2455 HAYWARD STREEN,ANN ARBOR,MI 48109, USA. RI Ridley, Aaron/F-3943-2011; OI Ridley, Aaron/0000-0001-6933-8534; Papitashvili, Vladimir/0000-0001-6955-4894 NR 26 TC 18 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1997 VL 102 IS A3 BP 4585 EP 4596 DI 10.1029/96JA02929 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WL464 UT WOS:A1997WL46400008 ER PT J AU Maynard, NC Weber, EJ Weimer, DR Moen, J Onsager, T Heelis, RA Egeland, A AF Maynard, NC Weber, EJ Weimer, DR Moen, J Onsager, T Heelis, RA Egeland, A TI How wide in magnetic local time is the cusp? An event study SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MIDDAY AURORAL BREAKUP; ELECTRIC-FIELD; MAGNETOPAUSE RECONNECTION; PARTICLE-PRECIPITATION; MAGNETOSPHERE; MODEL; MAGNETOSHEATH; IONOSPHERE; DYNAMICS; PLASMA AB A unique pass of the DMSP F11 satellite, longitudinally cutting through the cusp and mantle, combined with simultaneous optical measurements of the dayside cusp from Svalbard has been used to determine the width in local time of the cusp. We have shown from this event study that the cusp was at least 3.7 hours wide in magnetic local time. These measurements provide a lower limit for the cusp width. The observed cusp optical emissions are relatively constant, considering the processes which lead to the 630.0 nm emissions, and require precipitating electron flux to be added each minute during the DMSP pass throughout the local time extent observed by the imaging photometer and probably over the whole extent of the cusp defined by DMSP data. We conclude that the electron fluxes which produce the cusp aurora are from a process which must have been operable sometime during each minute but could have had both temporal and spatial variations. The measured width along with models of cusp precipitation provide the rationale to conclude that the region of flux tube opening in the dayside merging process involves the whole frontside magnetopause and cap extend beyond the dawn-dusk terminator. The merging process for this event was found to be continuous, although spatially and temporally variable. C1 PHILLIPS LAB,HANSCOM AFB,MA. UNIV COURSES SVALBARD,LONGYEARBYEN,NORWAY. NOAA,SPACE ENVIRONM CTR,BOULDER,CO. UNIV TEXAS,WILLIAM B HANSON CTR SPACE SCI,RICHARDSON,TX. UNIV OSLO,DEPT PHYS,OSLO,NORWAY. RP Maynard, NC (reprint author), MISSION RES CORP,1 TARA BLVD,SUITE 302,NASHUA,NH 03062, USA. NR 33 TC 26 Z9 26 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1997 VL 102 IS A3 BP 4765 EP 4776 DI 10.1029/96JA03433 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WL464 UT WOS:A1997WL46400025 ER PT J AU Fuselier, SA Anderson, BJ Onsager, TG AF Fuselier, SA Anderson, BJ Onsager, TG TI Electron and ion signatures of field line topology at the low-shear magnetopause SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID LATITUDE BOUNDARY-LAYER; PLASMA DEPLETION LAYER; SUBSOLAR MAGNETOSHEATH; DAYSIDE MAGNETOPAUSE; MAGNETIC SHEAR; RECONNECTION; DISTRIBUTIONS; CONVECTION; EVENTS AB Electrons above 50 eV are a sensitive indicator of field line topology at the magnetopause, particularly when the solar wind dynamic pressure is high and the shear across the boundary is low. AMPTE/CCE electron observations under conditions when these criteria are fulfilled indicate a clear topological transition from the magnetosheath to open field lines threading the magnetopause in the magnetosheath boundary, layer (MSBL). Once across the magnetopause and in the low latitude boundary layer (LLBL), the fast moving electrons are no longer a good indicator of magnetic field topology. In particular, the counterstreaming electron observations in this region are not an indicator of a closed magnetic topology. Rather, the field topology continues to be open, and the counterstreaming occurs because electrons from the magnetopause region move rapidly enough along the LLBL magnetic field to make it to the ionosphere, mirror, and return to the observation point. Slower moving ions provide important additional information on magnetic field topology in the LLBL. CCE observations discussed here indicate that two types of solar wind ion distributions are observed in this layer. One type consists of a single, heated distribution which resembles somewhat the electron distribution in the layer. The field-aligned velocity of this distribution is near zero. The other type consists of a unidirectional streaming distribution. The field-aligned velocity of this distribution is higher than in the adjacent magnetosheath. Combining these observations with magnetospheric ion observations (e.g., O+) in the LLBL and with electron observations in the MSBL, two distinct magnetic field topologies emerge for the low-shear magnetopause. The first, which gives rise to single, low-parallel-velocity and heated solar wind ion distributions in the LLBL, is magnetic reconnection poleward of the cusp. The second, which gives rise to unidirectional streaming solar wind ion distributions in the LLBL, is magnetic reconnection equatorward of the cusp. This type of component reconnection may not be sustained in a quasi-steady fashion. C1 JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. NOAA,SPACE ENVIRONM CTR,BOULDER,CO 80303. RP Fuselier, SA (reprint author), LOCKHEED PALO ALTO RES LABS,3251 HANOVER ST, DEPT H1-11,BLDG 252,PALO ALTO,CA 94304, USA. RI Anderson, Brian/I-8615-2012 NR 27 TC 74 Z9 75 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1997 VL 102 IS A3 BP 4847 EP 4863 DI 10.1029/96JA03635 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WL464 UT WOS:A1997WL46400031 ER PT J AU Jin, M Fread, DL AF Jin, M Fread, DL TI Dynamic flood routing with explicit and implicit numerical solution schemes SO JOURNAL OF HYDRAULIC ENGINEERING-ASCE LA English DT Article ID BREAK AB A characteristics-based, upwind, explicit numerical scheme is developed for one-dimensional (1D) unsteady flow modeling of natural rivers and implemented into the U.S. National Weather Service (NWS) FLDWAV model in combination with the original four-point implicit scheme. The new explicit scheme is extensively tested and compared with the implicit scheme. The study shows that the new explicit scheme provides improved versatility and accuracy in some situations, such as particularly large dam-break waves and other unsteady hows with near critical mixed-flow regimes. A technique for implicit-explicit multiple routing is introduced to incorporate the advantages of using both schemes within an application of the FLDWAV model. RP Jin, M (reprint author), NOAA,NATL WEATHER SERV,HYDROL RES LAB,1325 EAST WEST HIGHWAY,SILVER SPRING,MD 20910, USA. NR 19 TC 31 Z9 35 U1 0 U2 5 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9429 J9 J HYDRAUL ENG-ASCE JI J. Hydraul. Eng.-ASCE PD MAR PY 1997 VL 123 IS 3 BP 166 EP 173 DI 10.1061/(ASCE)0733-9429(1997)123:3(166) PG 8 WC Engineering, Civil; Engineering, Mechanical; Water Resources SC Engineering; Water Resources GA WM260 UT WOS:A1997WM26000001 ER PT J AU Weinberg, JR Leavitt, DF Lancaster, BA Capuzzo, JM AF Weinberg, JR Leavitt, DF Lancaster, BA Capuzzo, JM TI Experimental field studies with Mya arenaria (Bivalvia) on the induction and effect of hematopoietic neoplasia SO JOURNAL OF INVERTEBRATE PATHOLOGY LA English DT Article DE Mya arenaria; hematopoietic neoplasia; field experiment; survival; prevalence ID SOFT-SHELL CLAM; LONG-ISLAND-SOUND; POPULATION-DYNAMICS; NEW-BEDFORD; CELLS; PREVALENCE; MORTALITY; MOLLUSCA; BAY; TRANSMISSION AB A field experiment was conducted from 1991 to 1992 to examine induction and impact of hematopoietic neoplasia on the marine bivalve Mya arenaria in southeastern Massachusetts. Clams were collected from Little Buttermilk Bay and separated into three size classes (20-29, 30-39, and 40-49 mm shell length) in the laboratory. These sizes span the range of adults found in the population. A random subsample of these clams was taken to estimate disease prevalence at the start of the experiment, and this was found to be less than or equal to 10% in all size classes. Remaining clams were assigned randomly to two groups: Control and Treated. ''Controls'' were injected with filtered seawater, while ''Treated'' clams were injected with hemocytes extracted from diseased individuals. Injection of diseased hemocytes was performed to increase disease prevalence in the Treated group. Clams were returned to New Bedford Harbor, a more contaminated field location, where hematopoietic neoplasia is more prevalent, in January 1991, and characteristics of both groups were monitored for 555 days. Among Controls, probability of survival was size-dependent, with higher survival rates in larger clams. Treated clams had a lower probability of survival than Controls, and the magnitude of treatment effect increased with size class. The impact on survival was evident after 89 days, but it was first shown to be statistically significant after 189 days. Among Controls, probability of disease was strongly season-dependent, increasing in the large size class from 0.19 in spring to 0.50 in summer. During summer, Treated clams had a higher probability of being diseased than Controls. Among survivors, no significant sublethal effects due to treatment were detected in the field experiment. Experimental manipulation of disease prevalence may be a useful tool in future studies. In addition to results pertaining to disease, this study obtained long-term growth information, by size class, on somatic and reproductive tissue and shell size. (C) 1997 Academic Press. C1 WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543. RP Weinberg, JR (reprint author), NATL MARINE FISHERIES SERV,POPULAT DYNAM BRANCH,WOODS HOLE,MA 02543, USA. NR 48 TC 13 Z9 13 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2011 J9 J INVERTEBR PATHOL JI J. Invertebr. Pathol. PD MAR PY 1997 VL 69 IS 2 BP 183 EP 194 DI 10.1006/jipa.1996.4641 PG 12 WC Zoology SC Zoology GA WN412 UT WOS:A1997WN41200012 PM 9056469 ER PT J AU Biswas, P Wu, CY Zachariah, MR McMillin, B AF Biswas, P Wu, CY Zachariah, MR McMillin, B TI Characterization of iron oxide-silica nanocomposites in flames .2. Comparison of discrete-sectional model predictions to experimental data SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID AEROSOL DYNAMICS; KINETICS; SYSTEMS; REACTOR; GROWTH AB A discrete-sectional model accounting for particle formation by chemical reaction and growth by coagulation and condensation is developed to predict the evolution of the nanocomposite aerosol size distribution in a multicomponent iron-silicon system in a flame. Particle formation by nucleation of the vapor is represented by an Arrhenius-type rate expression, with the rate constant being obtained from experiments and simulation results reported in the literature. Precursor vapor concentrations and the second aerosol volume moment predictions are compared to laser-induced fluorescence (LIF) and light scattering intensity measurements from experiments described in Part I-20 Of the paper, The results elucidate the important formation and growth mechanisms of nanocomposite ferric oxide-silica particles in flame reactors, The role of operating parameters such as precursor characteristics and temperature profiles on the final product characteristics is established. C1 NIST, CHEM SCI & TECHNOL LAB, GAITHERSBURG, MD 20899 USA. RP UNIV CINCINNATI, AEROSOL & AIR QUAL RES LAB, ENVIRONM ENGN & SCI DIV, CINCINNATI, OH 45221 USA. NR 20 TC 46 Z9 46 U1 0 U2 15 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 1997 VL 12 IS 3 BP 714 EP 723 DI 10.1557/JMR.1997.0106 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA WM879 UT WOS:A1997WM87900025 ER PT J AU Belmonte, M Lee, SK AF Belmonte, M Lee, SK TI Contact damage in alumina reinforced with silicon carbide platelets SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID ACCUMULATION; COMPOSITES; FRACTURE; CERAMICS; FATIGUE C1 NIST, MAT SCI & ENGN LAB, GAITHERSBURG, MD 20899 USA. NR 20 TC 4 Z9 4 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD MAR 1 PY 1997 VL 16 IS 5 BP 379 EP 381 DI 10.1023/A:1018554629979 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA WL616 UT WOS:A1997WL61600012 ER PT J AU Szykman, S Cagan, J AF Szykman, S Cagan, J TI Constrained three-dimensional component layout using simulated annealing SO JOURNAL OF MECHANICAL DESIGN LA English DT Article ID PACKING PROBLEMS AB This research introduces a computational algorithm that uses simulated annealing to optimize three-dimensional component layouts. General component layout problems are characterized by three objectives: achieving high packing density, fitting components into a given container and satisfying spatial constraints on components. This paper focuses on the extension of a simulated annealing packing algorithm to a general layout algorithm through the implementation of a language of spatial constraints that are characteristic of layout problems. These constraints allow the designer to specify desired component proximities or to restrict translation or rotation of components based on a global origin or set of coordinate axes, or relative to other component locations or orientations. The layout of components from a cordless power drill illustrates the algorithm. RP Szykman, S (reprint author), NIST,ENGN DESIGN LAB,MFG SYST INTEGRAT DIV,GAITHERSBURG,MD 20899, USA. NR 18 TC 36 Z9 42 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-0472 J9 J MECH DESIGN JI J. Mech. Des. PD MAR PY 1997 VL 119 IS 1 BP 28 EP 35 DI 10.1115/1.2828785 PG 8 WC Engineering, Mechanical SC Engineering GA WT434 UT WOS:A1997WT43400005 ER PT J AU Tseng, SH Eggers, DF Blake, TA Beck, R Watts, RO Lovas, FJ Zobov, N AF Tseng, SH Eggers, DF Blake, TA Beck, R Watts, RO Lovas, FJ Zobov, N TI Infrared and microwave spectra of the N-2-propyne van der Waals cluster SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID INTERNAL-ROTATION; HIGH-RESOLUTION; SPECTROSCOPY; FORMAMIDE; PROPYNE; COMPLEX AB The infrared spectrum of N-14(2)-CH3CCH in the 3.0-mu m region has been observed and the rovibrational transitions have been assigned for the A (m = 0) and E (m = +/- 1) methyl top internal rotor states of this near slipped parallel van der Waals molecule. The E-state transitions were used to estimate the barrier to internal rotation as 10 cm(-1). The observed A-state microwave transitions of N-14(2)-CH3CCH, N-15(2)-CH3CCH, and N-15(2)-CH3CCD are split into doublets, This doubler splitting, which is too small to be observed in the infrared spectrum, is attributed to the internal motion of the N-2 moiety about an axis connecting the centers-of-mass of the molecules in the cluster; i.e., the N-2 molecule relates out of the heavy atom plane of the cluster. The splittings in the microwave spectra were fit to a barrier height of 71 cm(-1) for the hindered N-2 motion. (C) 1997 Academic Press. C1 UNIV WASHINGTON, DEPT CHEM, SEATTLE, WA 98195 USA. NIST, OPT TECHNOL DIV, GAITHERSBURG, MD 20899 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. ECOLE POLYTECH FED LAUSANNE, INST CHIM PHYS MOL, CH-1015 LAUSANNE, SWITZERLAND. UNIV MELBOURNE, SCH CHEM, PARKVILLE, VIC 3052, AUSTRALIA. INST PHYS APPL, NIZHNII NOVGOROD, RUSSIA. NR 17 TC 3 Z9 3 U1 1 U2 4 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAR PY 1997 VL 182 IS 1 BP 132 EP 147 DI 10.1006/jmsp.1996.7193 PG 16 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA WN854 UT WOS:A1997WN85400014 ER PT J AU OBrian, TR Lawler, JE AF OBrian, TR Lawler, JE TI Radiative lifetimes in CI and an atomic carbon beam source SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID OSCILLATOR STRENGTH MEASUREMENTS; NEUTRAL CARBON; VACUUM ULTRAVIOLET; TRANSITIONS; SPECTRA; LINES AB Radiative lifetimes for the 3s P-1(1)0, 4p D-1(2), and 4p S-1(0) levels of CI are measured using time-resolved laser-induced fluorescence (LIF) on a slow beam of atomic carbon. A simple method is reported for generating an atomic beam rich in metastable carbon atoms. (C) 1997 Elsevier Science Ltd. C1 UNIV WISCONSIN, DEPT PHYS, MADISON, WI 53706 USA. NIST, OPT TECHNOL DIV, GAITHERSBURG, MD 20899 USA. NR 22 TC 5 Z9 5 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 1997 VL 57 IS 3 BP 309 EP 315 DI 10.1016/S0022-4073(96)00136-7 PG 7 WC Optics; Spectroscopy SC Optics; Spectroscopy GA WL787 UT WOS:A1997WL78700002 ER PT J AU Musielok, J Veres, G Wiese, WL AF Musielok, J Veres, G Wiese, WL TI Some experimental tests of the spectroscopic coupling scheme of C I SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID NEUTRAL CARBON AB With a wall-stabilized are source, we have measured the relative line strengths for various neutral carbon lines between electronic states with angular momentum quantum numbers l = 0, 1, 2 (s, p, d) and principal quantum numbers 3, 4 and 5, in order to provide some experimental data on the spectroscopic coupling situation for this spectrum. C I is of interest because it is the first element in the periodic table for which calculations have predicted significant departures from LS-coupling line strengths for prominent transitions, while lighter atoms and ions adhere quite closely to the LS-coupling scheme. We have found indeed that for 3p-4d and 3p-5s lines the deviations of the measured line strengths from LS-coupling values become large, while the agreement with recent intermediate coupling calculations is very good. (C) 1997 Elsevier Science Ltd. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. OPOLE UNIV,PL-45052 OPOLE,POLAND. KFKI,RES INST PARTICLE & NUCL PHYS,H-1525 BUDAPEST 114,HUNGARY. NR 10 TC 15 Z9 15 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAR PY 1997 VL 57 IS 3 BP 395 EP 398 DI 10.1016/S0022-4073(96)00124-0 PG 4 WC Optics; Spectroscopy SC Optics; Spectroscopy GA WL787 UT WOS:A1997WL78700008 ER PT J AU Di Marzio, EA Yang, AJM AF Di Marzio, EA Yang, AJM TI Configurational entropy approach to the kinetics of glasses SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE Gibbs-Di Marzio entropy theory; glass kinetics; glass transition temperature; Vogel equation AB A kinetic theory of glasses is developed using equilibrium theory as a foundation. After establishing basic criteria for glass formation and the capability of the equilibrium entropy theory to describe the equilibrium aspects of glass formation, a minimal model for the glass kinetics is proposed. Our kinetic model is based on a trapping description of particle motion in which escapes from deep wells provide the rate-determining steps for motion. The formula derived for the zero frequency viscosity eta (0,T) is log eta (0,T) - B - AF(T)kT where F is the free energy and T the temperature. Contrast this to the Vogel-Fulcher law log eta (0,T) - B + A/(T - T-c). A notable feature of our description is that even though the location of the equilibrium second-order transition in temperature-pressure space is given by the break in the entropy or volume curves the viscosity and its derivative are continuous through the transition. The new expression for eta (0,T) has no singularity at a critical temperature T-c as in the Vogel-Fulcher law and the behavior reduces to the Arrhenius form in the glass region. Our formula for eta (0, T) is discussed in the context of the concepts of strong and fragile glasses, and the experimentally observed connection of specific heat to relaxation response in a homologous series of polydimethylsiloxane is explained. The frequency and temperature dependencies of the complex viscosity eta(omega ,T), the diffusion coefficient D(omega ,T), and the dielectric response epsilon(omega, T) are also obtained for our kinetic model and found to be consistent with stretched exponential behavior. C1 NIST, Mat Sci & Engn Lab, Div Polymers, Gaithersburg, MD 20899 USA. Armstrong World Ind, Lancaster, PA 17603 USA. RP Di Marzio, EA (reprint author), NIST, Mat Sci & Engn Lab, Div Polymers, Gaithersburg, MD 20899 USA. NR 66 TC 105 Z9 105 U1 6 U2 16 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 1997 VL 102 IS 2 BP 135 EP 157 DI 10.6028/jres.102.011 PG 23 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2816 UT WOS:000168726300002 PM 27805133 ER PT J AU Mandel, J AF Mandel, J TI Repeatability and reproducibility for pass/fail data SO JOURNAL OF TESTING AND EVALUATION LA English DT Article DE attribute data; interlaboratory studies; pass/fail data; reproducibility; repeatability AB A distribution-free method is presented for the evaluation of the reproducibility standard deviation in interlaboratory studies. The method is especially useful in the analysis of pass/fail interlaboratory data. RP Mandel, J (reprint author), NATL INST STAND & TECHNOL,US DEPT COMMERCE,GAITHERSBURG,MD 20899, USA. NR 0 TC 9 Z9 9 U1 1 U2 2 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD MAR PY 1997 VL 25 IS 2 BP 151 EP 153 PG 3 WC Materials Science, Characterization & Testing SC Materials Science GA WU021 UT WOS:A1997WU02100001 ER PT J AU Neff, WD AF Neff, WD TI The Denver Brown Cloud studies from the perspective of model assessment needs and the role of meteorology SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID DRAINAGE FLOWS; AIR-QUALITY; FRONT RANGE; MESOSCALE; COLORADO; LAYER AB The 1987-1988 Denver Brown Cloud Study addressed Denver's severe winter brown cloud episodes in a three-month field study followed by the application of a receptor-oriented chemical mass balance modeling method to apportion light extinction to primary emissions. However, this modeling method did not apportion light extinction from secondary particulates to individual sources. Recently, an independent meteorological and chemical modeling study, driven by the need to apportion secondary particles, reported on the initial numerical simulation of visibility for two days during the winter of 1987-1988. The MM4 meteorological model used in this recent study was operated in a four-dimensional, data-assimilation mode using standard, low-resolution synoptic observations and analyses. The chemical and aerosol numerical modeling system, which uses the MM4 meteorological model numerical output, was derived from the family of models developed for the National Acid Precipitation Assessment Program. This paper summarizes the meteorological features underlying the Denver brown cloud and assesses the consistency of the reported numerical simulations with the detailed meteorological observations available for the same periods. We found that the meteorological model, in its current form and range of application, does not address some of the critical mesoscale structures responsible for the initiation and maintenance of the brown cloud episodes studied nor, under some circumstances, does it properly predict boundary layer properties compared with observations. In addition, cloud systems and surface moisture fluxes are not addressed by the model, although many chemical processes depend on the presence of additional moisture. Comparison between model results and observations suggest that moist processes, particularly during the initiation phase of episodes, should be a critical issue for future experimental and modeling exercises. In addition, the limited model results available, when evaluated against the detailed boundary layer observations of the Brown Cloud Study, suggest that model uncertainties in the treatment of local terrain influence, boundary layer depth, and humidity may have obscured model overestimates of optical extinction. Finally, we suggest that although models will remain limited in many aspects, their use in combination with detailed observations of meteorology and chemistry will prove a valuable tool in the assessment of urban visibility issues. RP NOAA, METEOROL APPL & ASSESSMENT DIV, ENVIRONM TECHNOL LAB, BOULDER, CO 80303 USA. RI Neff, William/E-2725-2010 OI Neff, William/0000-0003-4047-7076 NR 34 TC 23 Z9 23 U1 1 U2 12 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 1096-2247 EI 2162-2906 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD MAR PY 1997 VL 47 IS 3 BP 269 EP 285 PG 17 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA WQ335 UT WOS:A1997WQ33500002 ER PT J AU Chestnut, LG Dennis, RL AF Chestnut, LG Dennis, RL TI Economic benefits of improvements in visibility: Acid Rain Provisions of the 1990 Clean Air Act Amendments SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article AB The Acid Rain Provisions (Title IV) of the Clean Air Act Amendments of 1990 call for about a 10 million ton reduction in annual SO, emissions in the United States. Although the provisions apply nationwide, most of the reduction will occur in the eastern half of the country, where use of high-sulfur coal for electricity generation is most common. One potentially large benefit of Title IV is the expected improvement in visibility conditions in the eastern United States due to the reductions in secondary sulfate aerosols. This paper combines available economic estimates of willingness to pay for improvements in visibility with current estimates of the difference between expected visibility conditions in the eastern United States with and without Title IV to estimate the expected visibility benefits of Title IV. The results suggest an annual value of $2.3 billion (in 1994 dollars) in the year 2010, as a result of visibility improvements due to Title IV in residential areas of the eastern United States. The results also suggest a possible additional annual value for eastern U.S. residents of as much as $1-2 billion for visibility improvements at national parks in the Southeast. C1 US EPA,ATMOSPHER RES & EXPOSURE ASSESSMENT LABS,NATL OCEAN & ATMOSPHER ADM,AIR RESOURCES LAB,RES TRIANGLE PK,NC 27711. RP Chestnut, LG (reprint author), HAGLER BAILLY SERV INC,PO DRAWER O,BOULDER,CO 80306, USA. NR 17 TC 15 Z9 15 U1 1 U2 2 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD MAR PY 1997 VL 47 IS 3 BP 395 EP 402 PG 8 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA WQ335 UT WOS:A1997WQ33500011 ER PT J AU Ilavsky, J Allen, AJ Long, GG Krueger, S Berndt, CC Herman, H AF Ilavsky, J Allen, AJ Long, GG Krueger, S Berndt, CC Herman, H TI Influence of spray angle on the pore and crack microstructure of plasma-sprayed deposits SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID X-RAY-DIFFRACTION; NEUTRON-SCATTERING; COATINGS; CERAMICS; ZIRCONIA; ALUMINA AB To understand the influence of processing parameters on the microstructure of plasma-sprayed deposits, small-angle neutron scattering measurements were made of the processing-parameter-dependent specific surface area of the voids in gray alumina deposits, These studies indicate that the voids are in the form of pores between the splats and around inclusions or unmelted particles, and are also in the form of cracks within the splats which may develop during cooling, The porous volume increases as the angle between the spray gun and the substrate (the ''spray angle'') decreases, This study also indicates that the cracks are preferentially oriented, and that the crack orientation also depends on the spray angle, The interlamellar pores, however, are preferentially oriented parallel to the substrate surface, and the orientation of the pore is independent of the spray angle. C1 NIST,GAITHERSBURG,MD 20899. SUNY STONY BROOK,STONY BROOK,NY 11794. RI Ilavsky, Jan/D-4521-2013 OI Ilavsky, Jan/0000-0003-1982-8900 NR 39 TC 82 Z9 84 U1 2 U2 6 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAR PY 1997 VL 80 IS 3 BP 733 EP 742 PG 10 WC Materials Science, Ceramics SC Materials Science GA WQ570 UT WOS:A1997WQ57000027 ER PT J AU Munro, RG AF Munro, RG TI Effects of oxidation on the flaw-limited strengths of brittle materials SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID FRACTURE ORIGINS AB The weakest-link statistical model is used to derive an approximate relation describing the influence of oxidation or corrosion on the fracture strengths of brittle materials. Differences in strength under comparable short-term oxidizing and nonoxidizing exposures are found to be proportional to delta m/m(2) where m is the Weibull modulus. RP Munro, RG (reprint author), NIST,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAR PY 1997 VL 80 IS 3 BP 811 EP 812 PG 2 WC Materials Science, Ceramics SC Materials Science GA WQ570 UT WOS:A1997WQ57000044 ER PT J AU Liao, Q Pitner, WR Stewart, G Hussey, CL Stafford, GR AF Liao, Q Pitner, WR Stewart, G Hussey, CL Stafford, GR TI Electrodeposition of aluminum from the aluminum chloride-1-methyl-3-ethylimidazolium chloride room temperature molten salt plus benzene SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID BUTYLPYRIDINIUM CHLORIDE; IONIC LIQUIDS; MELTS; CONDUCTIVITY; DISSOLUTION; DEPOSITION; MECHANISM; BATH AB The constant current electrodeposition of bulk aluminum on copper substrates was investigated in the Lewis acidic [> 50 mole percent (m/o) AlCl3] aluminum chloride-1-methyl-3-ethylimidazolium chloride room temperature molten salt (AlCl3-MeEtimCl). Although aluminum can be electroplated from the neat molten salt, we have found that the quality of the electrodeposit is greatly enhanced by the addition of benzene as a ''cosolvent.'' Electrodeposits produced in such melts exhibited a grain size on the order of 5 to 15 mu m. The lattice parameters of these electrodeposits were slightly smaller than the Joint Committee on Powder Diffraction Standards (JCPDS) value; this was attributed to the presence of vacancies in the aluminum lattice that were present at concentrations ranging from about 0.1 to 0.5 atomic percent (a/o). The copper substrate was found to have a slight (311) texture as determined by x-ray diffraction; however, ail of the electrodeposits exhibited a preferred (220) crystallographic orientation with the intensity of the (311) reflection being equal to that of a randomly oriented sample. The (200) and (111) reflections were relatively weak. The relative intensity of the (220) reflection increased and those for the (311), (200), and (111) orientations decreased as the benzene concentration was increased. A Williamson-Hall treatment indicated that microstrain in the electrodeposits was essentially nonexistent. C1 NIST,DEPT MET,GAITHERSBURG,MD 20899. RP Liao, Q (reprint author), UNIV MISSISSIPPI,DEPT CHEM,UNIVERSITY,MS 38677, USA. NR 38 TC 79 Z9 88 U1 5 U2 41 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAR PY 1997 VL 144 IS 3 BP 936 EP 943 DI 10.1149/1.1837510 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA WR237 UT WOS:A1997WR23700028 ER PT J AU Parrish, DF Derber, JC Purser, RJ Wu, WS Pu, ZX AF Parrish, DF Derber, JC Purser, RJ Wu, WS Pu, ZX TI The NCEP global analysis system: Recent improvements and future plans SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article; Proceedings Paper CT 2nd WMO International Symposium on Assimilation of Observations in Meteorology and Oceanography CY MAR 13-17, 1995 CL TOKYO, JAPAN SP World Meteorol Org AB This paper describes significant changes to the U.S. National Centers for Environmental Prediction (NCEP, formerly NMC, the National Meteorological Center) global data assimilation system that were made operational in January, 1995. The emphasis is on changes to the 3D-variational analysis, which has been running operationally since June, 1991. The changes include additions of new data types, modifications to the background error, and addition of a weak constraint on divergence tendency. A uniform improvement in fit of the 6 hour forecast guess to all observation types was observed in parallel tests over a period of 9 months. Most of the improvement is believed to be due to the addition of the divergence tendency constraint. The improved performance extends to medium range forecasts, as measured by anomaly correlation scores for geopotential height. Current research activities related to global and regional data assimilation at NCEP are also briefly described. RP Parrish, DF (reprint author), NATL CTR ENVIRONM PREDICT, ENVIRONM MODELING CTR, WASHINGTON, DC USA. NR 11 TC 30 Z9 33 U1 0 U2 0 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 1997 VL 75 IS 1B BP 359 EP 365 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG476 UT WOS:A1997XG47600018 ER PT J AU Kalnay, E Anderson, DLT Bennett, AF Busalacchi, AJ Cohn, SE Courtier, P Derber, J Lorenc, AC Parrish, D Purser, J Sato, N Schlatter, T AF Kalnay, E Anderson, DLT Bennett, AF Busalacchi, AJ Cohn, SE Courtier, P Derber, J Lorenc, AC Parrish, D Purser, J Sato, N Schlatter, T TI Data assimilation in the ocean and in the atmosphere: What should be next? SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Editorial Material C1 UNIV OXFORD, OXFORD, ENGLAND. OREGON STATE UNIV, CORVALLIS, OR 97331 USA. NASA, GODDARD SPACE FLIGHT CTR, WASHINGTON, DC USA. JAPAN METEOROL AGCY, TOKYO, JAPAN. RP Kalnay, E (reprint author), NATL CTR ENVIRONM PREDICT, WASHINGTON, DC USA. RI Kalnay, Eugenia/F-4393-2010; Cohn, Stephen/K-1954-2012; OI Cohn, Stephen/0000-0001-8506-9354; Kalnay, Eugenia/0000-0002-9984-9906 NR 9 TC 9 Z9 9 U1 0 U2 0 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 1997 VL 75 IS 1B BP 489 EP 496 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG476 UT WOS:A1997XG47600027 ER PT J AU Spector, N Sugar, J Wyart, JF AF Spector, N Sugar, J Wyart, JF TI Analysis of the third spectrum of dysprosium (Dy III) SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article AB The third spectrum of dysprosium has been observed in a sliding-spark discharge with a 10.7-m normal-incidence spectrograph in the wavelength region between 2007 and 5020 Angstrom. Of the 2500 lines that were attributed to Dy III, 544 are classified. With these data 106 energy levels were established, including five of the I-5 ground term of the 4f(10) configuration, 49 of 4f(9)5d, 15 of 4f(9)6s, and 37 of 4f(9)6p. The levels have been interpreted theoretically and have been assigned percentage compositions in the most appropriate coupling schemes. Using semiempirical calculations with least-squares-fitted radial parameters, we have obtained average deviations between experimental and calculated levels of +/-49, +/-29, and +/-16 cm(-1) for the 4f(9)5d, the 4f(9)6p, and the 4f(9)6s configurations, respectively. The overlapping configurations 4f(9)5d and 4f(9)6s show slight evidence of configuration interaction. This analysis leaves Pm III as the last spectrum of a doubly ionized rare earth to remain uninterpreted. With these data, a value of 184 970 +/- 800 cm(-1) has been derived for the ionization energy. (C) 1997 Optical Society of America. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. CNRS,F-91405 ORSAY,FRANCE. RP Spector, N (reprint author), SOREQ NUCL RES CTR,IL-81800 YAVNE,ISRAEL. NR 11 TC 19 Z9 19 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAR PY 1997 VL 14 IS 3 BP 511 EP 521 DI 10.1364/JOSAB.14.000511 PG 11 WC Optics SC Optics GA WM652 UT WOS:A1997WM65200004 ER PT J AU Dapkunas, SJ AF Dapkunas, SJ TI Measurement methods and standards for processing and application of thermal barrier coatings SO JOURNAL OF THERMAL SPRAY TECHNOLOGY LA English DT Article DE measurement methods; standards; thermal barrier coatings ID ADHESION AB Application of thermal barrier coatings deposited by thermal spray, physical vapor and possibly other methods is expected to be extended from aircraft gas turbines to industrial and utility gas turbines as well as diesel engines. This increased usage implies the participation of greater numbers of processors and users, making the availability of standards for process control and property measurement more important, In this paper, available standards specifically for processing and evaluation of thermal barrier coatings are identified as well as those generally applicable to coatings and those needed but unavailable. C1 NIST,DIV CERAM,GAITHERSBURG,MD 20899. NR 17 TC 6 Z9 7 U1 2 U2 2 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 1059-9630 J9 J THERM SPRAY TECHN JI J. Therm. Spray Technol. PD MAR PY 1997 VL 6 IS 1 BP 67 EP 76 DI 10.1007/BF02646314 PG 10 WC Materials Science, Coatings & Films SC Materials Science GA WM436 UT WOS:A1997WM43600008 ER PT J AU McMillin, BK Zachariah, MR AF McMillin, BK Zachariah, MR TI Two-dimensional imaging of CF2 density by laser-induced fluorescence in CF4 etching plasmas in the gaseous electronics conference reference cell SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID RADIO-FREQUENCY PLASMA; RADICALS; DISCHARGES; SPECTROSCOPY; PHOTOPHYSICS; ABSORPTION; REACTOR; SILICON; SYSTEM; ARGON AB Spatially resolved two-dimensional maps of the relative CF2 density in low-pressure radio-frequency Ar/CF4/O-2 discharges generated within a parallel-plate Gaseous Electronics Conference reference cell have been obtained using planar laser-induced fluorescence imaging. The experiments cover a wide range of pressure, composition, flow rate, and power deposition conditions (13.3-133.3 Pa, 1%-100% CF4, 1%-10% O-2, 5-100 seem, 3-35 W). Typically, the centerline (r = 0) axial CF2 distribution was symmetric with the local peak occurring near the center of the electrode gap, but, in all cases, significant radial variations in CF2 density were observed (14%-45% standard deviation from the mean) with the peak density occurring near the edge of the discharge region. Varying the pressure led to significant changes in both the magnitude and spatial distribution of CF2 density, while varying the composition, flow rate, and power primarily affected only the magnitude of the CF2 density, with only modest changes in the spatial distribution. Based on image-averaged comparisons, the CF2 density increased with power, pressure, and CF4 mole fraction, decreased with addition of oxygen, and varied nonmonotonically with flow rate. C1 NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. NR 33 TC 19 Z9 19 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAR-APR PY 1997 VL 15 IS 2 BP 230 EP 237 DI 10.1116/1.580517 PG 8 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA WP127 UT WOS:A1997WP12700004 ER PT J AU Zimmerman, NM AF Zimmerman, NM TI A simple fabrication method for nanometer-scale thin-metal stencils SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article AB We describe a simple fabrication method for the production of thin-metal stencils using the overlayer him from lift-off patterning. While such stencils have been fabricated before using other techniques, this method has several advantages. The advantages include the fact that this method requires only the capability to perform standard lithography and thin-film deposition, but does not require any dry etching or other sophisticated capabilities. In addition, by using the negative of the lithographically defined pattern, we show that a small number of trenches of lateral size down to 100 nm, in an otherwise continuous stencil, can be produced using electron-beam lithography with very little beam rastering necessary (i.e., small exposure times). We also argue that any group with access to simple photolithography and thin-film deposition facilities should be able to make these stencils, with openings much smaller than the lithography resolution limit. RP Zimmerman, NM (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 7 TC 0 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1997 VL 15 IS 2 BP 369 EP 372 DI 10.1116/1.589321 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA WU267 UT WOS:A1997WU26700033 ER PT J AU Gardner, WS Cavaletto, JF Cotner, JB Johnson, JR AF Gardner, WS Cavaletto, JF Cotner, JB Johnson, JR TI Effects of natural light on nitrogen cycling rates in the Mississippi River plume SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID DISSOLVED ORGANIC-MATTER; INTERMEDIATE SALINITIES; COASTAL WATERS; AMMONIUM; PHYTOPLANKTON; BACTERIA; BACTERIOPLANKTON; MINERALIZATION; REGENERATION; METABOLISM AB Isotope-dilution experiments with (NH4+)-N-15 were conducted on near-surface water samples in the Mississippi River plume during May 1992 and July 1993 to quantify community cycling rates for ammonium and determine whether regeneration rates are enhanced by light. Experiments done under natural light in May showed ranges of potential uptake and regeneration rates of 0-0.4 mu M h(-1) and 0-0.18 mu M h(-1). Samples collected offshore from the Atchafalaya River and the Southwest Pass of the Mississippi River in July yielded potential uptake rates of 0.4-1.8 mu M h(-1) under natural light vs. 0-0.45 mu M h(-1) in the dark. Ammonium regeneration rates ranged from 0.08 to 0.75 mu M h(-1) in the light and from 0.02 to 0.3 mu M h(-1) in the dark. The observed light/dark regeneration-rate differences imply a close coupling between phytoplankton production and ammonium regeneration. The ratio of bacterial cell-specific regeneration to uptake rates increased in the outer regions of the plume, indicating a changing contribution of bacterial-sized organisms to nitrogen cycling processes in different regions of the plume. C1 NOAA,GREAT LAKES ENVIRONM RES LAB,ANN ARBOR,MI 48105. TEXAS A&M UNIV,DEPT WILDLIFE & FISHERIES SCI,COLLEGE STN,TX 77843. UNIV MICHIGAN,COOPERAT INST LIMNOL & ECOSYST RES,ANN ARBOR,MI 48105. NR 30 TC 28 Z9 29 U1 0 U2 6 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAR PY 1997 VL 42 IS 2 BP 273 EP 281 PG 9 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA XK561 UT WOS:A1997XK56100007 ER PT J AU Gannon, DP Read, AJ Craddock, JE Fristrup, KM Nicolas, JR AF Gannon, DP Read, AJ Craddock, JE Fristrup, KM Nicolas, JR TI Feeding ecology of long-finned pilot whales Globicephala melas in the western north Atlantic SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE food habits; bycatch; Globicephala melas; Loligo pealei ID STOMACH CONTENTS AB Stomach contents from 30 long-finned pilot whales Globicephala melas captured incidentally in the Distant Water Fleet (DWF) mackerel fishery off the northeastern United States were examined. Several methods oi assessing prey importance were used in order to construct a true representation of the pilot whale diet. Separate analyses of trace (free, durable body parts from well-digested prey) and non-trace (relatively intact prey) food materials were conducted to address biases caused by differential rates of digestion and passage. Squids dominated the diet and long-finned squid Loligo pealei was the most important prey, but we noted large yearly fluctuations in prey importance. Metric multidimensional scaling analyses of trace and non-trace stomach contents of individual whales suggest that many animals were caught while feeding opportunistically near fishing operations, resulting in a bias of non-trace (intact) stomach contents. The diversity of prey in this study was greater than previous reports of the food habits oi western North Atlantic long-finned pilot whales. C1 NATL MARINE FISHERIES SERV, WOODS HOLE, MA 02543 USA. RP Gannon, DP (reprint author), WOODS HOLE OCEANOG INST, WOODS HOLE, MA 02543 USA. NR 26 TC 31 Z9 35 U1 3 U2 14 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PD MAR PY 1997 VL 148 IS 1-3 BP 1 EP 10 DI 10.3354/meps148001 PG 10 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA WW714 UT WOS:A1997WW71400001 ER PT J AU Terrados, J Duarte, CM Kenworthy, WJ AF Terrados, J Duarte, CM Kenworthy, WJ TI Experimental evidence for apical dominance in the seagrass Cymodocea nodosa SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE seagrass; apical dominance; Cymodocea nodosa ID DYNAMICS; PLANTS; GROWTH AB The existence of apical dominance in the seagrass Cymodocea nodosa (Ucria) Ascherson was elucidated by in situ experimental manipulation. Removal of the apical meristem of a C. nodosa horizontal rhizome promoted an increase in the branching rate of the rhizome which was mostly driven by a change in the growth form of the nearest vertical rhizome into horizontal growth. Although the elongation of the branches increased when the rhizome apical meristem was eliminated, total plant growth was reduced by severing of the apical meristem. C1 NOAA, NATL MARINE FISHERIES SERV, SE FISHERIES SCI CTR, BEAUFORT LAB, BEAUFORT, NC 28516 USA. RP Terrados, J (reprint author), CSIC, CTR ESTUDIOS AVANZADOS BLANES, CAMI SANTA BARBARA SN, E-17300 BLANES, GIRONA, SPAIN. RI Terrados, Jorge/B-1062-2008; Duarte, Carlos M/A-7670-2013 OI Terrados, Jorge/0000-0002-0921-721X; Duarte, Carlos M/0000-0002-1213-1361 NR 13 TC 34 Z9 34 U1 0 U2 3 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PD MAR PY 1997 VL 148 IS 1-3 BP 263 EP 268 DI 10.3354/meps148263 PG 6 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA WW714 UT WOS:A1997WW71400023 ER PT J AU Dowell, DC Bluestein, HB Jorgensen, DP AF Dowell, DC Bluestein, HB Jorgensen, DP TI Airborne Doppler radar analysis of supercells during COPS-91 SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE CONVECTIVE SYSTEM; TORNADIC STORMS; KINEMATIC STRUCTURE; PRECIPITATION; THUNDERSTORMS; ROTATION; PROPAGATION; GENERATION; BUOYANCY; DRYLINE AB On 26 May 1991, NOAA P-3 airborne Doppler radar data were collected near two tornadic supercells in the southern Plains during the Cooperative Oklahoma Profiler Studies (COPS-91) field program. The 3-cm radar mounted in the tail of the aircraft was operated using the fore-aft scanning technique (FAST). Both storms were sampled just minutes after each had produced a tornado. The COPS-91 storms are the first tornadic supercells to be sampled extensively by airborne Doppler radar using the FAST methodology. Pseudo-dual-Doppler analyses of a dissipating storm in southwest Kansas show no remaining low-level circulation, even though the storm had just produced a tornado. The analyses of a storm in northwest Oklahoma reveal better-defined features in the wind field near the surface. In contrast to what has been previously observed in post-tornadic supercells, the cyclonic vorticity in both storms was greater aloft than at low levels. The 26 May 1991 storms provide further evidence that supercells often contain multiple updrafts and mesocyclones. Cyclical mesocyclogenesis was occurring in the northwest Oklahoma storm while pseudo-dual-Doppler data were being collected. Airborne Doppler radar provides the potential for obtaining datasets throughout the lifetime of a storm at close range, where the observational geometry can be controlled to minimize known errors. The lessons learned from COPS-91 were incorporated into the airborne Doppler strategies employed during the subsequent Verificafion of the Origins of Rotation in Tornadoes Experiment (1994-95). C1 NOAA,NSSL,BOULDER,CO 80303. RP Dowell, DC (reprint author), UNIV OKLAHOMA,SCH METEOROL,100 E BODY,ROOM 1310,NORMAN,OK 73019, USA. RI Dowell, David/E-7855-2015 NR 55 TC 13 Z9 13 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAR PY 1997 VL 125 IS 3 BP 365 EP 383 DI 10.1175/1520-0493(1997)125<0365:ADRAOS>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WJ869 UT WOS:A1997WJ86900004 ER PT J AU Currie, LA Eglinton, TI Benner, BA Pearson, A AF Currie, LA Eglinton, TI Benner, BA Pearson, A TI Radiocarbon ''dating'' of individual chemical compounds in atmospheric aerosol: First results comparing direct isotopic and multivariate statistical apportionment of specific polycyclic aromatic hydrocarbons SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7th Conference on Accelerator Mass Spectrometry CY MAY 20-24, 1996 CL TUCSON, AZ SP AMS DE microchemical dating; source apportionment; accelerator mass spectrometry; atmospheric aerosol; polycyclic aromatic hydrocarbons; GC/AMS; PCGC; urban particle standard reference material; PAHs from coal tar standard reference material; molecular level C-14 measurement ID ACCELERATOR MASS-SPECTROMETRY; SEDIMENTS; SAMPLES; SYSTEM; CARBON; C-14 AB Recent instrumental developments which allow radiocarbon (C-14) determinations on microgram quantities of organic material have revolutionized our ability to apportion fossil and biogenic sources of trace carbonaceous gases and aerosols in the environment. The chemical complexity of carbonaceous aerosol, however, presents a challenge in the interpretation of its average isotopic composition. For this reason, there has long been an interest in radiocarbon measurements of specific classes of compounds, or even individual trace compounds of particular environmental concern, such as the polycyclic aromatic hydrocarbons (PAHs). The PAHs hold special interest because they are produced at trace levels in combustion processes; they exhibit compound-specific genotoxicity; and they have the potential to serve as ''molecular markers'' or tracers for specific ambient aerosol sources, Prior to the work reported here, inferences from ambient studies concerning molecular tracer capabilities have been indirect, relying on circumstantial evidence and/or multivariate statistical techniques. In the present study we demonstrate, for the first time, the ability to measure the C-14 content of individual, trace organic compounds (PAHs) in atmospheric aerosol. The research utilized a special, well characterized atmospheric reference material, where individual PAHs were radiocarbon ''dated'' using off-line gas chromatography/accelerator mass spectrometry (GC/AMS). Separation of individual compounds in sufficient amounts for AMS was accomplished by automated preparative capillary gas chromatography (PCGC). Results showed the PAHs dated to be primarily fossil in origin, and lent support to an earlier multivariate statistical study suggesting that benzo[ghi]perylene might serve as a useful tracer for soot generated by motor vehicles, although this assessment must be viewed as tentative because of potential interference from other compounds incompletely removed from the purified PAH fraction. C1 WOODS HOLE OCEANOG INST, DEPT MARINE CHEM & GEOCHEM, WOODS HOLE, MA 02543 USA. RP Currie, LA (reprint author), NATL INST STAND & TECHNOL, CHEM SCI & TECHNOL LAB, GAITHERSBURG, MD 20899 USA. RI Pearson, Ann/A-6723-2009 NR 20 TC 36 Z9 41 U1 3 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1997 VL 123 IS 1-4 BP 475 EP 486 DI 10.1016/S0168-583X(96)00783-5 PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA WT653 UT WOS:A1997WT65300094 ER PT J AU Ye, J Ma, LS Daly, T Hall, JL AF Ye, J Ma, LS Daly, T Hall, JL TI Highly selective terahertz optical frequency comb generator SO OPTICS LETTERS LA English DT Article ID PARAMETRIC OSCILLATOR; PHASE-LOCKING; DIVISION AB Using a 10.5-GHz resonant electro-optic modulator placed inside a resonant optical cavity, we generated an optical frequency comb with a span wider than 3 THz. The optical resonator consists of three mirrors, with the output coupler being a thin Fabry-Perot cavity with a free spectral range of 2 THz and a finesse of 400. Tuning this filter cavity onto resonance with a particular high-order sideband permits efficient output coupling of the desired sideband power from the comb generator, while keeping all other sidebands inside for continued comb generation. This spectrally pure output light was then heterodyne detected by another laser with a frequency offset of the order of 1 THz. (C) 1997 Optical Society of America. C1 NATL INST STAND & TECHNOL, BOULDER, CO 80309 USA. E CHINA NORMAL UNIV, DEPT PHYS, SHANGHAI 200062, PEOPLES R CHINA. NEW FOCUS CORP, SANTA CLARA, CA 95051 USA. RP Ye, J (reprint author), UNIV COLORADO, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. RI Ye, Jun/C-3312-2011 NR 13 TC 27 Z9 27 U1 0 U2 15 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 1 PY 1997 VL 22 IS 5 BP 301 EP 303 DI 10.1364/OL.22.000301 PG 3 WC Optics SC Optics GA WJ765 UT WOS:A1997WJ76500016 PM 18183182 ER PT J AU Grother, PJ Candela, GT Blue, JL AF Grother, PJ Candela, GT Blue, JL TI Fast implementations of nearest neighbor classifiers SO PATTERN RECOGNITION LA English DT Article DE non-parametric classifiers; kd trees; k nearest neighbors; distance metrics; Karhunen-Loeve transform; OCR AB Standard implementations of non-parametric classifiers have large computational requirements. Parzen classifiers use the distances of an unknown vector to all N prototype samples, and consequently exhibit O(N) behavior in both memory and time. We describe four techniques for expediting the nearest neighbor methods: replacing the linear search with a new kd tree method, exhibiting approximately O(N-1/2) behavior; employing an L-infinity instead of L-2 distance metric; using variance-ordered features; and rejecting prototypes by evaluating distances in low dimensionality subspaces. We demonstrate that variance-ordered features yield significant efficiency gains over the same features linearly transformed to have uniform variance. We give results for a large OCR problem, but note that the techniques expedite recognition for arbitrary applications. Three of four techniques preserve recognition accuracy. (C) 1997 Pattern Recognition Society. C1 NIST,INFORMAT TECHNOL LAB,MATH MODELLING GRP,GAITHERSBURG,MD 20899. RP Grother, PJ (reprint author), NIST,INFORMAT TECHNOL LAB,IMAGE PROC GRP,GAITHERSBURG,MD 20899, USA. NR 14 TC 42 Z9 42 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0031-3203 J9 PATTERN RECOGN JI Pattern Recognit. PD MAR PY 1997 VL 30 IS 3 BP 459 EP 465 DI 10.1016/S0031-3203(96)00098-2 PG 7 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA WV667 UT WOS:A1997WV66700008 ER PT J AU Thomson, R Carlsson, AE AF Thomson, R Carlsson, AE TI The brittle-ductile behaviour of materials: Modelling the effect of interatomic force laws SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID EMBEDDED-ATOM METHOD; TRANSITION-METALS; DISLOCATION NUCLEATION; CRACK; CRITERION; EMISSION; LATTICE AB We present a model for brittle-ductile behaviour of materials containing interfaces based on the idea that the criteria for fracture can be couched as a balance between elastic driving forces and lattice resistance terms. This approach leads to a simple block construction for the lattice resistance term for blunting dislocation emission, which can be generalized to apply to first-principles quantum-mechanical bonding calculations for the crack. We have tested the model with a generic two-dimensional hexagonal lattice with universal binding energy relation (UBER) pair force laws and shown that the model gives quantitative results. The only exception is when the bonding relations at the crack tip lead to significant lattice trapping, for which the material is more ductile than predicted. With the generic system (which should be useful in a qualitative way for more realistic materials), we find that firstly the cross-over between ductile and brittle behaviour is determined by the local bonding at the interface atoms, secondly the cross-over occurs at lambda approximate to 0.17 (in units of the lattice spacing), where lambda is the range parameter in the UBER force law for a system emitting at an angle of about 60 degrees to the cleavage plane and thirdly the cross-over is independent of the spring constants in the interface but depends on the crystallography of the crack-emission system and on the elastic mismatch between the two sublattices at the interface. Consequences for chemical embrittlement are discussed. C1 WASHINGTON UNIV, DEPT PHYS, ST LOUIS, MO 63130 USA. RP Thomson, R (reprint author), NATL INST STAND & TECHNOL, MAT SCI & ENGN LAB, GAITHERSBURG, MD 20899 USA. NR 26 TC 10 Z9 10 U1 0 U2 5 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD MAR PY 1997 VL 75 IS 3 BP 749 EP 769 PG 21 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA WN480 UT WOS:A1997WN48000010 ER PT J AU Reader, J Acquista, N AF Reader, J Acquista, N TI Spectrum and energy levels of doubly-ionized zirconium (ZrIII) SO PHYSICA SCRIPTA LA English DT Article ID Y-III; YTTRIUM; REGION; VI AB The spectrum of doubly-ionized zirconium ZrIII, was observed from 630 Angstrom to 4610 Angstrom with sliding spark discharges on the 10.7-m normal-incidence vacuum spectrograph at the National Institute of Standards and Technology. The spectral analysis of C. C. Kiess, J. Res. Natl. Bur. Std (U.S.) 56, 167 (1956), was considerably revised and extended. Experimental energies were obtained for almost all levels of the 4d(2), 4d5s, 5s(2), 4d5p, 5s5p, 4d5d, 4d6s, 4d6p, 4d4f, 5p(2), 5s6s, 5s5d, 4d5f, 4d5g and 5s4f configurations as well as for a few levels of 4d7p and 4d6f. A total of 482 lines were classified as transitions between 139 energy levels. From the optimized energy level values, a system of Ritz-type wavelengths with uncertainties varying from about 0.005 Angstrom to 0.003 Angstrom was determined. The observed configurations were theoretically interpreted by means of Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels. The fitted energy parameters were used to calculate oscillator strengths and transition probabilities for all classified lines. An improved value of the ionization energy was obtained from the 4d4f, 4d5f and 4d5g configurations. The adopted value is 186 880 +/- 30 cm(-1) (23.170 +/- 0.004 eV). RP Reader, J (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 20 TC 15 Z9 15 U1 0 U2 2 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PD MAR PY 1997 VL 55 IS 3 BP 310 EP 329 DI 10.1088/0031-8949/55/3/009 PG 20 WC Physics, Multidisciplinary SC Physics GA WN824 UT WOS:A1997WN82400009 ER PT J AU Serpa, FG Bell, EW Meyer, ES Gillaspy, JD Roberts, JR AF Serpa, FG Bell, EW Meyer, ES Gillaspy, JD Roberts, JR TI Kr spectra from an electron-beam ion trap: 300 nm to 460 nm SO PHYSICAL REVIEW A LA English DT Article ID MAGNETIC DIPOLE TRANSITIONS; LINE; KRYPTON; XXXVI; CU AB Kr spectra from 300 nm to 460 nm produced in an electron-beam ion trap (EBIT) are reported in this work. The spectra include magnetic dipole (M1) transitions from Kr XXIII and Kr XXII, as well as electric dipole (E1) lines of Kr II and Kr III. Two new capabilities of the EBIT at the National Institute of Standards and Technology, time resolved data acquisition and extracted ion analysis, are used to aid in the charge state identification. C1 UNIV NOTRE DAME,DEPT PHYS,NOTRE DAME,IN 46556. DE SHAW CO,NEW YORK,NY 10036. RP Serpa, FG (reprint author), NIST,ATOM PHYS DIV,GAITHERSBURG,MD 20899, USA. NR 21 TC 25 Z9 25 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1997 VL 55 IS 3 BP 1832 EP 1835 DI 10.1103/PhysRevA.55.1832 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WN174 UT WOS:A1997WN17400038 ER PT J AU Smith, JR Kim, JB Lineberger, WC AF Smith, JR Kim, JB Lineberger, WC TI High-resolution threshold photodetachment spectroscopy of OH- SO PHYSICAL REVIEW A LA English DT Article ID NEGATIVE-IONS; CROSS-SECTIONS; ELECTRON PHOTODETACHMENT; AFFINITY; DYNAMICS; STATES; AUTODETACHMENT; MOLECULES; ENOLATE; ANIONS AB Relative photodetachment cross sections for rotational thresholds of the hydroxide anion were measured using a coaxial laser-ion beam spectrometer. The thresholds correspond to transitions from the J=1 and J=2 states of X (1) Sigma(+) OH- to the J=3/2 state of X (2) Pi(3/2) OH. Best fits of the data give cross sections that scale with energy above threshold as (E-E(th))(0.18+/-0.06) and (E-E(th))(0.21+/-0.05) for the two thresholds, respectively. This non-Wigner law energy dependence of the cross section results from the long-range r(-2) interaction between the dipole and the departing electron. Experimental results were compared with the predictions of a strong-coupling model of charge-dipole interaction devised by Engelking and good qualitative agreement was observed. When the resolution and range of the data for transitions that terminate in the lower Lambda-doublet component is such that the Lambda-doublet splitting is resolved, one observes the (E-E(th))(1/2) behavior predicted by the Wigner law. This result is explained in terms of the effect of the Lambda doubling upon the r(-2) charge-dipole interaction. From the threshold frequencies. an OH electron affinity of 14 741.02(3) cm(-1) was determined. C1 UNIV COLORADO, JILA, BOULDER, CO 80309 USA. NIST, BOULDER, CO 80309 USA. RP UNIV COLORADO, DEPT CHEM & BIOCHEM, CAMPUS BOX 215, BOULDER, CO 80309 USA. NR 46 TC 113 Z9 114 U1 1 U2 20 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 MAR PY 1997 VL 55 IS 3 BP 2036 EP 2043 DI 10.1103/PhysRevA.55.2036 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WN174 UT WOS:A1997WN17400063 ER PT J AU Chung, YS Djuric, N Wallbank, B Dunn, GH Bannister, ME Smith, ACH AF Chung, YS Djuric, N Wallbank, B Dunn, GH Bannister, ME Smith, ACH TI Resonance interference and absolute cross sections in near-threshold electron-impact excitation of the 3s(2) S-1->3s3p P-3 and 3s(2) S-1->3s3p P-1 transitions in Ar6+ SO PHYSICAL REVIEW A LA English DT Article ID ION EXCITATION; IONIZATION; SI-2+; BEAMS; KR6+ AB Strong resonance features were observed in the near-threshold excitation of Ar6+. Absolute total cross sections for electron-impact excitation of the 3s(2) S-1-->3s3p P-3(o) and 3s(2) S-1-->3s3p P-1(o) transitions in Ar6+ were measured by using the merged electron-ion beams energy loss technique. The results are compared with the R-matrix close-coupling theory (CCR) and the independent-process isolated-resonance distorted-wave approximation. Observed disagreement between CCR theory and experiment at the near-threshold peak for the 3s(2) S-1-->3s3p P-3(o) transition is interpreted to be due to very sensitive resonance interference. C1 UNIV COLORADO,BOULDER,CO 80309. OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. UNIV LONDON UNIV COLL,LONDON WC1E 6BT,ENGLAND. ST FRANCIS XAVIER UNIV,DEPT PHYS,ANTIGONISH,NS B2G 2W5,CANADA. RP Chung, YS (reprint author), NIST,JILA,BOULDER,CO 80309, USA. NR 24 TC 26 Z9 26 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1997 VL 55 IS 3 BP 2044 EP 2049 DI 10.1103/PhysRevA.55.2044 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WN174 UT WOS:A1997WN17400064 ER PT J AU Wang, H Li, J Wang, XT Williams, CJ Gould, PL Stwalley, WC AF Wang, H Li, J Wang, XT Williams, CJ Gould, PL Stwalley, WC TI Precise determination of the dipole matrix element and radiative lifetime of the K-39 4p state by photoassociative spectroscopy SO PHYSICAL REVIEW A LA English DT Article ID COOLED ATOMS; RANGE; MOLECULES AB Rovibrational levels (v = 0-30) of the 0(g)(-) ''pure long-range'' state of K-39(2) are observed by photoassociative spectroscopy of ultracold potassium atoms prepared in a high-density magneto-optical trap. The measured molecular binding energies are used to precisely determine the long-range dipole-dipole potential constant C-3(II) of the K(4s) + K(4p) asymptote and the radiative lifetime of the 4p state. We determine C-3(II) = -5.456(9) zJ nm(3) (-8.445(14) a.u.), tau(4 P-2(3/2)) = 26.34(5) ns, and tau(4 P-2(1/2)) = 26.69(5) ns. Our result is a significant improvement in precision over previous lifetime measurements and agrees well with the recent fast-beam experiment [U. Volt and H. Schmoranzer, Phys. Scr. T65, 48 (1996)]. C1 NIST,DIV ATOM PHYS,GAITHERSBURG,MD 20899. UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. RP Wang, H (reprint author), UNIV CONNECTICUT,DEPT PHYS,U-46,STORRS,CT 06269, USA. RI Williams, Carl/B-5877-2009 NR 37 TC 76 Z9 76 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1997 VL 55 IS 3 BP R1569 EP R1572 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WN174 UT WOS:A1997WN17400003 ER PT J AU Wiesler, DG Suzuki, M Suzuki, IS Rosov, N AF Wiesler, DG Suzuki, M Suzuki, IS Rosov, N TI Magnetic neutron-scattering study of MnCl2-graphite intercalation compound SO PHYSICAL REVIEW B LA English DT Article ID ELECTRON-SPIN-RESONANCE; PHASE-TRANSITIONS; XY-MODEL; GRAPHITE; TEMPERATURE; SYSTEMS; MNCL2 AB The in-plane spin order of MnCl2 graphite intercalation compound has been studied between 63 mK and 30 K by elastic neutron scattering. This compound approximates a classical XY antiferromagnet on a triangular lattice. Below 7.5 K magnetic critical scattering peaks are observed at wave vectors incommensurate with. the MnCl2 and graphene sublattices. As the temperature is raised, the cell contracts towards a commensurate 2 root 3x2 root 3 magnetic unit cell. The ground-state in-plane spin configuration is explained by an exchange Hamiltonian that includes no fewer than three shells of nearest neighbors in the plane. The magnetic peaks have a Lorentzian shape and are broader than resolution down to 63 mK, well below the peak in the magnetic susceptibility at 1.1 K. No evidence of three-dimensional magnetic correlations was found at any temperature. C1 GEORGE WASHINGTON UNIV,DEPT PHYS,WASHINGTON,DC 20052. SUNY BINGHAMTON,DEPT PHYS,BINGHAMTON,NY 13902. NATL INST STAND & TECHNOL,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. NR 41 TC 4 Z9 4 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1997 VL 55 IS 10 BP 6382 EP 6391 DI 10.1103/PhysRevB.55.6382 PG 10 WC Physics, Condensed Matter SC Physics GA WP345 UT WOS:A1997WP34500046 ER PT J AU Lynn, JW Skanthakumar, S Huang, Q Sinha, SK Hossain, Z Gupta, LC Nagarajan, R Godart, C AF Lynn, JW Skanthakumar, S Huang, Q Sinha, SK Hossain, Z Gupta, LC Nagarajan, R Godart, C TI Magnetic order and crystal structure in the superconducting RNi(2)B(2)C materials SO PHYSICAL REVIEW B LA English DT Article ID NICKEL BORIDE CARBIDES; ANTIFERROMAGNETIC ORDER; NEUTRON-DIFFRACTION; B-C; HONI2B2C; DYNI2B2C; LUNI2B2C; DEPENDENCE; LNNI2B2C; ERNI2B2C AB Neutron-diffraction measurements have been carried out to investigate the crystal structure, magnetic structures, and magnetic phase transitions in RNi(2)B(2)C (R = Y, Ce, Pr, Nd, Tb, Dy, Ho, Er, Tm, and Yb). The materials that order magnetically exhibit a wide variety of both commensurate and incommensurate magnetic structures, which argues strongly that the dominant exchange interactions are of the indirect Ruderman-Kittel-Kasuya-Yosida type. The Nd system exhibits a commensurate antiferromagnetic ordering at 4.8 K, with wave vector delta=(1/2,0,1/2) and moment direction along a (or equivalently with delta=(0,1/2,1/2) and moment direction along b in this tetragonal system). For Dy (T-N=10.6 K), Pr (T-N=4.0 K), and the low-temperature phase of Ho, the magnetic structure is also a commensurate antiferromagnet that consists of ferromagnetic sheets of rare-earth moments in the a-b plane, with the sheets coupled antiferromagnetically along the c axis [delta=(0,0,1)]. Pr is not superconducting, while for Dy (T-c=6 K) and Ho (T-c=8 K) this magnetic order coexists with superconductivity. For Ho, though, the magnetic state that initially forms at T-N approximate to 8.5 K is an incommensurate spiral antiferromagnetic state along the c axis in which the direction of these ferromagnetic sheets are rotated in the a-b plane by similar to 17 degrees from their low-temperature antiparallel configuration [delta=(0,0,0.91)]. The intensity for this spiral state reaches a maximum near the reentrant superconducting transition (similar to 5 K); the spiral state then collapses at lower temperature in favor of the commensurate antiferromagnetic state. An incommensurate a-axis modulation, with delta=(0.55,0,0), is also observed above the spiral-antiferromagnetic transition, but it exists over a narrower temperature range than the spiral state, and also collapses near the reentrant superconducting transition. The Er system forms an incommensurate, transversely polarized spin-density wave (SDW) state at T-N=6.8 K, with delta=(0.553,0,0) and moment direction along b (or with delta along b and the moment direction along a). The SDW squares up at low T, and coexists with the superconducting state (T-c=11 K) over the full temperature range where magnetic order is present. Tb, which does not superconduct, orders with a very similar wave vector, but the SDW is longitudinally polarized in this case and again squares up at low T. Tm orders at T-N=1.5 K in a transversely polarized SDW state, but with the moments along the c axis and delta=(0.093,0.093,0), This state is coexistent with superconductivity (T-c=11 K). No significant magnetic moment is found to develop on the Ni site in any of the materials, and there is no magnetic ordering of any kind in the Y, Yb, or Ce materials. Profile refinements have also been carried out on these same samples to investigate the systematics of the crystallography, and the crystal structure is I4/mmm over the full range of compositions and temperatures investigated. The area of the a-b plane and the volume of the unit cell both decrease smoothly with either decreasing lanthanide radius or decreasing temperature, but the strong boron-carbon and nickel-carbon bonding then forces the c axis to expand. C1 UNIV MARYLAND,CTR SUPERCOND RES,COLLEGE PK,MD 20742. UNIV MARYLAND,MAT ENGN PROGRAM,COLLEGE PK,MD 20742. ARGONNE NATL LAB,ADV PHOTON SOURCE,ARGONNE,IL 60439. TATA INST FUNDAMENTAL RES,BOMBAY 400005,MAHARASHTRA,INDIA. CNRS,UPR 209,F-92195 MEUDON,FRANCE. RP Lynn, JW (reprint author), NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899, USA. NR 66 TC 266 Z9 268 U1 1 U2 22 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1997 VL 55 IS 10 BP 6584 EP 6598 DI 10.1103/PhysRevB.55.6584 PG 15 WC Physics, Condensed Matter SC Physics GA WP345 UT WOS:A1997WP34500069 ER PT J AU Schwabedissen, A Benck, EC Roberts, JR AF Schwabedissen, A Benck, EC Roberts, JR TI Langmuir probe measurements in an inductively coupled plasma source SO PHYSICAL REVIEW E LA English DT Article ID ENERGY DISTRIBUTION FUNCTION; REFERENCE CELL; DISCHARGE; ION; DIAGNOSTICS AB Measurements of the plasma potential, electron density, effective electron temperature,and electron energy distribution function (EEDF) have been performed with Langmuir probes in planar, electrostatically shielded, low-pressure inductively coupled plasmas. The plasma source is a modification of the Gaseous Electronics Conference RF Reference Cell [P. J. Hargis et al., Rev. Sci. Instrum. 65, 140 (1994)] with the upper electrode replaced by a five-turn planar coil and a quartz vacuum interface. Four different rare gases (Ar, Kr, Xe, and Ne), a He:Ar (96:4) mixture, and O-2 and N-2 were investigated. We found that with increasing ionization potential of the rare gas the electron density decreases, while the effective electron temperature and the plasma potential increase. Non-Maxwellian EEDFs were observed for all energies for O-2 and N-2 discharges as well as for the rare gases above the energy range for elastic collisions. Spatially resolved measurements confirm that the EEDF is determined by spatially averaged quantities instead of the local electric field. RP Schwabedissen, A (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 35 TC 80 Z9 80 U1 1 U2 10 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 1997 VL 55 IS 3 BP 3450 EP 3459 DI 10.1103/PhysRevE.55.3450 PN B PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA WN935 UT WOS:A1997WN93500051 ER PT J AU Wang, YC VanBrunt, RJ AF Wang, YC VanBrunt, RJ TI Calculation of electron transport in Ar/N-2 and He/Kr gas mixtures - Implications for validity of the Blanc's law method SO PHYSICS OF PLASMAS LA English DT Article ID TRANSFER CROSS-SECTION; DRIFT VELOCITIES; SCATTERING; COEFFICIENTS; ATTACHMENT; SF6; N-2 AB The electron drift velocities and corresponding mean energies have been calculated numerically using an approximate two-term solution of the Boltzmann transport equation for Ar/N-2 gas mixtures at electric field-to-gas density ratios (E/N) below 2.0 x 10(-20) Vm(2) (20 Td) and for He/Kr mixtures at E/N below 5.0 x 10(-21) Vm(2) (5.0 Td). The results are compared with predictions obtained from a method proposed by Chiflikian based on an ''analog of Blanc's law'' [Phys. Plasmas 2, 3902 (1995)]. Large differences are found between the results derived from the Blanc's law method and those found here from solutions of the transport equation that indicate serious errors and Limitations associated with use of the Blanc's law method to compute drift velocities in gas mixtures. (C) 1997 American Institute of Physics. C1 UNIV TENNESSEE, DEPT PHYS, KNOXVILLE, TN 37996 USA. RP Wang, YC (reprint author), NIST, DIV ELECT, ELECT & ELECT ENGN LAB, GAITHERSBURG, MD 20899 USA. NR 26 TC 4 Z9 4 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1997 VL 4 IS 3 BP 551 EP 554 DI 10.1063/1.872563 PG 4 WC Physics, Fluids & Plasmas SC Physics GA WL771 UT WOS:A1997WL77100005 ER PT J AU Monroe, C Bollinger, J AF Monroe, C Bollinger, J TI Atomic physics in ion traps SO PHYSICS WORLD LA English DT Article ID QUANTUM RP Monroe, C (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. RI Monroe, Christopher/G-8105-2011 NR 9 TC 2 Z9 2 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-8585 J9 PHYS WORLD JI Phys. World PD MAR PY 1997 VL 10 IS 3 BP 37 EP 42 PG 6 WC Physics, Multidisciplinary SC Physics GA WM302 UT WOS:A1997WM30200025 ER PT J AU Meyer, WR Bengtson, JL Jansen, JK Russell, RW AF Meyer, WR Bengtson, JL Jansen, JK Russell, RW TI Relationships between brood size and parental provisioning performance in chinstrap penguins during the chick guard phase SO POLAR BIOLOGY LA English DT Article ID BREEDING ADELIE PENGUINS; PYGOSCELIS-ANTARCTICA; ISLAND; VARIABILITY; ENERGETICS; SEABIRDS; GENTOO; GROWTH; KRILL AB Chinstrap penguins (Pygoscelis antarctica) normally lay two eggs, but brood size is often reduced by mortality during incubation or after hatching. We hypothesized that this variation in brood size would affect the parents' foraging behavior and their chick provisioning performance. We studied patterns of adult foraging trip duration and frequency, food load delivery, and chick growth rates in relation to brood size during the guard phase in four breeding seasons (1991-1994) on Seal Island, Antarctica. Within a given year, parents with two chicks made more frequent foraging trips to sea and may have transported larger food loads to the nest; however, the duration of foraging trips was unrelated to brood size. Overall, parents with two chicks spent similar to 15% more time at sea than parents with only one chick. Both the frequency and duration of foraging trips varied between years. Foraging trip duration may partly reflect the birds' foraging radius, which probably varies with time in response to shifts in krill distribution. Chick growth rate varied betwen years, but was related to brood size only in 1992, when chicks from two-chick broods grew significantly more slowly than chicks from one-chick broods. Food loads transported to chicks, as well as chick growth rates, were highest in 1994, when concurrent hydroacoustic studies indicated that regional krill biomass was severely depressed. This apparent anomaly suggests that the spatial scale of the krill survey may have been too coarse to detect some high-density krill aggregations within the penguins' foraging range. C1 NOAA,NATL MARINE MAMMAL LAB,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115. NR 28 TC 9 Z9 9 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0722-4060 J9 POLAR BIOL JI Polar Biol. PD MAR PY 1997 VL 17 IS 3 BP 228 EP 234 DI 10.1007/s003000050126 PG 7 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA WJ468 UT WOS:A1997WJ46800005 ER PT J AU WongNg, W Snyder, RL Park, C Antipov, E McClune, WF AF WongNg, W Snyder, RL Park, C Antipov, E McClune, WF TI The ICDD/PDF Superconductor SubFile SO POWDER DIFFRACTION LA English DT Article ID CU-O SYSTEM; BULK SUPERCONDUCTIVITY; 120-K; TC; PB; (TL0.5PB0.5)SR2CA2CU3O9; LA AB The activity of the high T-c task group of the ICDD Ceramic Subcommittee is described. This activity includes the compilation of X-ray powder diffraction patterns of the high T-c superconductors and related phases identified from the International Centre for Diffraction Data/Powder Diffraction File (ICDD/PDF). The coverage of this ICDD/PDF Superconductor SubFile (SC) includes high T-c phases and their structurally related phases, products of elemental substitution in the high T-c phases, phases found in the phase diagrams containing the high T-c phases, as well as potential reaction products with commonly used sample containers, and potential conventional low-temperature (metallic and nonmetallic) superconductors. (C) 1997 International Centre for Diffraction Data. C1 ALFRED UNIV,NEW YORK STATE COLL CERAM,ALFRED,NY 14802. MOSCOW MV LOMONOSOV STATE UNIV,MOSCOW,RUSSIA. ICDD,NEWTOWN SQ,PA 19073. RP WongNg, W (reprint author), NIST,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 32 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0885-7156 J9 POWDER DIFFR JI Powder Diffr. PD MAR PY 1997 VL 12 IS 1 BP 13 EP 15 PG 3 WC Materials Science, Characterization & Testing SC Materials Science GA XB996 UT WOS:A1997XB99600004 ER PT J AU Chang, JL Avery, SK Riddle, AC Palo, SE Gage, KS AF Chang, JL Avery, SK Riddle, AC Palo, SE Gage, KS TI First results of tropospheric gravity wave momentum flux measurements over Christmas Island SO RADIO SCIENCE LA English DT Article ID VHF RADAR OBSERVATIONS; UPPER-ATMOSPHERE RADAR; MU-RADAR; LOWER STRATOSPHERE; MESOSCALE VARIABILITY; LOWER THERMOSPHERE; WIND PROFILER; MESOSPHERE; AUSTRALIA; ADELAIDE AB The importance of gravity wave effects on various dynamical processes has been well documented in the upper and middle atmosphere. However, less is known about these waves in the lower atmosphere. Whereas many studies of longer-period waves have previously been conducted using wind profiler data, this paper is an effort to quantify the short-term motions of the troposphere. We will present some of the initial tropospheric gravity wave horizontal variance and momentum flux estimates calculated from Christmas Island wind profiler data collected during 1994. A coplanar antenna beam configuration was used for this analysis. For periods shorter than 8 hours, the monthly vertical fluxes of zonal and meridional momentum were estimated to be between +/-0.02 kg m(-1) s(-2) and +/-0.01 kg m(-1) s(-2), respectively. The resulting net accelerations of the mean flow were in the range of +/-0.1 m s(-1) d(-1). In addition to the high-frequency results, we will discuss some of the difficulties we encountered while processing the data. In order to determine the robustness of applying a coplanar beam analysis method to tropospheric data, we have compared the results of two data sets that were created using two independently developed cleaning algorithms on the same original raw data. These results show that the high-frequency calculations are sensitive to the quality of the cleaned data used for this analysis. As long as the uncertainties associated with cleaning the data are considered, it is possible to establish the magnitude of the vertical momentum fluxes and the resulting accelerations in the troposphere. C1 NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,BOULDER,CO 80307. NATL OCEAN & ATMOSPHER ADM,AERON LAB,BOULDER,CO. UNIV COLORADO,DEPT ELECT & COMP ENGN,BOULDER,CO 80309. RP Chang, JL (reprint author), UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,CAMPUS BOX 216,BOULDER,CO 80309, USA. OI PALO, SCOTT/0000-0002-4729-4929 NR 44 TC 15 Z9 15 U1 2 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAR-APR PY 1997 VL 32 IS 2 BP 727 EP 748 DI 10.1029/96RS03468 PG 22 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA WP942 UT WOS:A1997WP94200036 ER PT J AU Meyer, DL Townsend, EC Thayer, GW AF Meyer, DL Townsend, EC Thayer, GW TI Stabilization and erosion control value of oyster cultch for intertidal marsh SO RESTORATION ECOLOGY LA English DT Article ID SALT-MARSH; BAY AB Oyster cultch was added to the lower intertidal fringe of three created Spartina alterniflora marshes to examine its value in protecting the marsh from erosion. Twelve 5-m-wide plots were established at each site, with six randomly selected plots unaltered (noncultched) and cultch added to the remaining (cultched) plots. Within each cultched plot, cultch was placed along the low tide fringe of the marsh during July 1992, in a band 1.5 m wide by 0.25 m deep. Marsh-edge vegetation stability and sediment erosion were measured for each plot from September 1992 to April 1994. Significant differences (p < 0.05) in marsh-edge vegetation change were detected at the only south-facing site after a major southwester storm. Significantly different rates of sediment erosion and accretion also were observed at this same site. Areas upland of the marsh edge in the cultched areas showed an average accretion of 6.3 cm, while noncultched treatment areas showed an average loss of 3.2 cm. A second site, with northern orientation, also experienced differential sediment accretion and erosion between treatment type, caused instead by boat wakes that were magnified by the abutment of a dredge effluent pipe across the entire front fringe of the site. During this period we observed significant differences in sediment accumulation, with the areas upland of the marsh edge in the cultched treatment having an average accretion of 2.9 cm and the noncultched an average loss of 1.3 cm. RP Meyer, DL (reprint author), SE FISHERIES SCI CTR,NATL MARINE FISHERIES SERV,BEAUFORT LAB,101 PIVERS ISL RD,BEAUFORT,NC 28516, USA. NR 25 TC 75 Z9 76 U1 3 U2 38 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 SN 1061-2971 J9 RESTOR ECOL JI Restor. Ecol. PD MAR PY 1997 VL 5 IS 1 BP 93 EP 99 DI 10.1046/j.1526-100X.1997.09710.x PG 7 WC Ecology SC Environmental Sciences & Ecology GA WP943 UT WOS:A1997WP94300010 ER PT J AU Newbury, DE Griffith, E AF Newbury, DE Griffith, E TI Part II of the special issue on environmental scanning electron microscopy SO SCANNING LA English DT Editorial Material RP Newbury, DE (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430 SN 0161-0457 J9 SCANNING JI Scanning PD MAR PY 1997 VL 19 IS 2 BP 70 EP 70 PG 1 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA WP939 UT WOS:A1997WP93900001 ER PT J AU Wight, S Gillen, G Herne, T AF Wight, S Gillen, G Herne, T TI Development of environmental scanning electron microscopy electron beam profile imaging with self-assembled monolayers and secondary ion mass spectroscopy SO SCANNING LA English DT Article DE environmental scanning electron microscope; self-assembled monolayer; Monte Carlo; SAM; ESEM; backscatter ID ALKANETHIOL MONOLAYERS AB A method for demonstrating the scattering of the primary electron beam in the presence of a gas has been developed. A self-assembled decanethiol monolayer is damaged by primary beam electrons. The damaged portion of the monolayer is exchanged with another thiol-containing molecule by immersion in solution. The resulting film is imaged using a secondary ion mass spectrometer. Three-dimensional reconstruction of the data yields a representation of scattered electrons in the gaseous environment of the environmental scanning electron microscope. C1 NIST,PROC MEASUREMENTS DIV,GAITHERSBURG,MD 20899. RP Wight, S (reprint author), NIST,SURFACE & MICROANAL SCI DIV,GAITHERSBURG,MD 20899, USA. NR 6 TC 13 Z9 13 U1 0 U2 0 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430 SN 0161-0457 J9 SCANNING JI Scanning PD MAR PY 1997 VL 19 IS 2 BP 71 EP 74 PG 4 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA WP939 UT WOS:A1997WP93900002 ER PT J AU Wight, SA AF Wight, SA TI Better visualization inside the environmental scanning electron microscope through the infrared chamberscope coupled with a mirror SO SCANNING LA English DT Article DE environmental scanning electron microscope (ESEM); chamberscope AB Clearances are tight inside the specimen chamber of the environmental scanning electron microscope (ESEM), and it is difficult to see the relative positions of detectors and specimens through the viewport. For example, the relative placement of the energy-dispersive spectrometer (EDS) and the specimen is critical for attaining reasonable x-ray efficiency while protecting the detector window from damage. An infrared chamberscope and mirror attachment were added to improve the visibility inside the chamber. RP Wight, SA (reprint author), NIST,MICROANAL RES GRP,2222-A113,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 SN 0161-0457 J9 SCANNING JI Scanning PD MAR PY 1997 VL 19 IS 2 BP 125 EP 126 PG 2 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA WP939 UT WOS:A1997WP93900012 ER PT J AU Smith, Z Watari, S Dryer, M Manoharan, PK McIntosh, PS AF Smith, Z Watari, S Dryer, M Manoharan, PK McIntosh, PS TI Identification of the solar source for the 18 October 1995 magnetic cloud SO SOLAR PHYSICS LA English DT Article ID CORONAL MASS EJECTIONS; INTERPLANETARY SHOCKS; ECLIPTIC-PLANE; ASSOCIATIONS; EVOLUTION; FLARES; MHD AB It is necessary to identify signatures of solar sources in order to improve predictions of solar-caused geomagnetic activity. This is not a straightforward task as the relationship is not well understood. We apply an algorithm, derived from numerical simulations to identify the solar source of an interplanetary event that was observed by the WIND spacecraft on October 18, 1995 and was followed by a geomagnetic storm. No specific geomagnetic activity had been predicted at Space Weather Operations (SWO) in Boulder, CO, on the basis of earlier solar observations. The algorithm is used to estimate the time and location of the expected solar source of this interplanetary event. A review of solar observations prior to the WIND observations showed that solar activity precursors could be identified. A long-duration-event was seen by GOES in soft X-rays at the same time as a type IV burst was observed in metric radio wavelengths, and a rearrangement of fields was observed by the soft X-ray telescope on the Yohkoh satellite. This suggests that the algorithm is useful for post facto identification of solar sources, and that such combinations of solar activity should be further investigated for use in geomagnetic forecasting. C1 COMMUN RES LABS,KOGANEI,TOKYO 184,JAPAN. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. OBSERV PARIS,DASOP,F-92195 MEUDON,FRANCE. HELIOSYNOPT,BOULDER,CO 80301. RP Smith, Z (reprint author), NOAA,SPACE ENVIRONM CTR,325 BROADWAY,BOULDER,CO 80303, USA. RI xue, yansheng/A-9712-2012 NR 30 TC 19 Z9 19 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 MAR PY 1997 VL 171 IS 1 BP 177 EP 190 DI 10.1023/A:1004998824082 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WT120 UT WOS:A1997WT12000012 ER PT J AU Wiese, WL AF Wiese, WL TI Atomic spectroscopic databases on the World Wide Web SO SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY LA English DT News Item RP Wiese, WL (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0584-8547 J9 SPECTROCHIM ACTA B JI Spectroc. Acta Pt. B-Atom. Spectr. PD MAR PY 1997 VL 52 IS 3 BP 279 EP 280 DI 10.1016/S0584-8547(96)01666-7 PG 2 WC Spectroscopy SC Spectroscopy GA XG261 UT WOS:A1997XG26100001 ER PT J AU Lamaze, GP ChenMayer, H Langland, JG Downing, RG AF Lamaze, GP ChenMayer, H Langland, JG Downing, RG TI Neutron depth profiling with the new NIST cold neutron source SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE boron; depth profiling; focusing; neutrons; nitrogen AB Neutron depth profiling (NDP) is a method of near-surface analysis for isotopes that undergo neutron-induced positive Q-value charged particle reactions, e.g. (n, alpha) and (n, p). The method is based on measuring the energy loss of the charged particles as they exit the specimen. Depending on the material under study, depths of up to 10 mu m can be profiled and depth resolutions of the order of 15 nm can be obtained The most studied analytes via NDP at the National Institute of Standards and Technology (NIST) are boron, lithium and nitrogen. These analytes have been determined in a variety of matrices. The NIST research reactor has recently undergone a major upgrade, including the addition of a new liquid-hydrogen cold source, which reaches a lower effective temperature and more fully illuminates the neutron guides. The cold neutron depth profiling (CNDP) facility has been placed on a curved super-mirror guide. Because of the guide curvature, the NDP chamber does not directly view the reactor and its associated fast neutrons and gamma rays, and therefore a 135 cm thick sapphire filter used previously in front of the beam port is no longer necessary. The increase in the neutron fluence rate at the end of the guide leads to an improvement in detection limit of more than a factor of four over the previous depth profiling instrument. The reduction in the gamma-ray background in the chamber will improve oar ability to measure elements such as nitrogen. (C) 1997 by John Wiley & Sons, Ltd. RP Lamaze, GP (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 9 TC 5 Z9 5 U1 1 U2 8 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD MAR PY 1997 VL 25 IS 3 BP 217 EP 220 DI 10.1002/(SICI)1096-9918(199703)25:3<217::AID-SIA226>3.0.CO;2-3 PG 4 WC Chemistry, Physical SC Chemistry GA WP460 UT WOS:A1997WP46000009 ER PT J AU Szunyogh, I Kalnay, E Toth, Z AF Szunyogh, I Kalnay, E Toth, Z TI A comparison of Lyapunov and optimal vectors in a low-resolution GCM SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article ID TRANSIENT ERROR GROWTH; OPTIMAL PERTURBATIONS; BAROTROPIC INSTABILITY; LOCAL PREDICTABILITY; ENSEMBLE PREDICTION; SPECTRAL MODEL; CIRCULATION; NMC; ASSIMILATION; SENSITIVITY AB We compare the first local Lyapunov vector (LLV) and the leading optimal vectors in a T10/18 level truncated version of the National Centers for Environmental Prediction global spectral model. The leading LLV is a vector toward which all other perturbations turn and hence it is characterized by the fastest possible growth over infinitely long time periods, while the optimal vectors are perturbations that maximize growth for a finite time period, with respect to a chosen norm. Linear tangent model breeding experiments without convection at T10 resolution show that arbitrary random perturbations converge within a transition period of 3 to 4 days to a single LLV. We computed optimal vectors with the Lanczos algorithm, using the total energy norm. For optimization periods shorter than the transition period (about 3 days), the horizontal structure of the leading initial optimal vectors differs substantially From that of the leading LLV, which provides maximum sustainable growth, There are also profound differences between the two types of vectors in their vertical structure. While the 24-hour optimal vectors rapidly become similar to the LLV in their vertical structure, changes in their horizontal structure are: very slow. As a consequence, their amplification factor drops and stays well below that of the LLV for an extended period after the optimization period ends, This may have an adverse effect when optimal vectors with short optimization periods are used as initial perturbations for medium-range ensemble forecasts. The optimal vectors computed for 3 days or longer are different. In these vectors, the fastest growing initial perturbation has a horizontal structure similar to that of the leading LLV, and its major difference from the LLV, in the vertical structure, tends to disappear by the end of the optimization period. Initially, the optimal vectors are highly unbalanced and the rapid changes in their vertical structure are associated with geostrophic adjustment. The kinetic energy of the initial optimal vectors peaks in the lower troposphere, whereas in the LLV the maximum is around the jet level. During the integration the phase of the streamfunction held of the optimal vectors, with respect to their corresponding temperature field, is rapidly shifted 180 degrees. And, due to drastic changes that also rake place in the vertical temperature distribution, the maximum baroclinic shear shifts from the lower troposphere to just below the jet level. Just after initial rime, when the geostrophic adjustment dominates, the leading optimal vectors exhibit a growth rate significantly higher than that of the LLV. By the end of the period of optimization, however, the growth rate associated with the leading optimal vectors drops to or below the level of the Lyapunov exponent. The transient super-lyapunov growth associated with the leading optimal vectors is due to a one-time-only rapid rotation of the optimal vectors toward the leading LLVs. The nature of this rapid rotation depends on the length of the optimization period and the norm chosen, We speculate that the initial optimal vectors computed with commonly used norms may not be realizable perturbations in a dynamical system (that is not forced by random noise) since the leading optimal vectors are directions in the phase space from which perturbations are ''repelled''. By contrast, the leading LLV is the vector toward which all random perturbations, including the optimal vectors, are attracted, which gives the LLV a unique role in linear perturbation development. C1 NATL CTR ENVIRONM PREDICT, CAMP SPRINGS, MD 20746 USA. EOTVOS LORAND UNIV, DEPT METEOROL, BUDAPEST, HUNGARY. 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 59 TC 54 Z9 55 U1 0 U2 3 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 MAR PY 1997 VL 49 IS 2 BP 200 EP 227 DI 10.1034/j.1600-0870.1997.00004.x PG 28 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA WP068 UT WOS:A1997WP06800004 ER PT J AU Fischer, DA Hu, ZS Hsu, SM AF Fischer, D. A. Hu, Z. S. Hsu, S. M. TI Tribochemical and thermochemical reactions of stearic acid on copper surfaces in air as measured by ultra-soft X-ray absorption spectroscopy SO TRIBOLOGY LETTERS LA English DT Article DE X-ray absorption spectroscopy; stearic acid; copper; steel; gold; adsorption; orientation measurements; Langmuir-Blodgett films; tribological effects AB For copper, steel, and gold surfaces the chemisorption of stearic acid was found to adsorb via the acid head group, displacing adsorbed contaminants on the surfaces. Tribochemical and thermochemical reactions of stearic acid adsorbed (in air) on a copper surface, were studied by ultra-soft X-ray absorption spectroscopy above the carbon and oxygen K edges. Chemisorbed stearic acid was found to adsorb in both monodentate and bidentate sites. The bidentate surface configuration was increased after the occurrence of the tribochemical reactions induced by surface rubbing. When the surface was subjected to a vacuum thermal annealing process, a reduction in bidentate configuration was observed. Carbon-K-edge X-ray absorption measurements were used to determine the tilt of the alkyl molecular chain from the surface normal, before and after the tribochemical or thermal annealing surface treatments. A stable chemically bonded molecular adsorbed layer persists on the surface even after these surface treatments. The molecular orientation of the molecules is also generally preserved after rubbing. C1 [Fischer, D. A.; Hu, Z. S.; Hsu, S. M.] Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fischer, DA (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 16 TC 12 Z9 13 U1 0 U2 3 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD MAR PY 1997 VL 3 IS 1 BP 35 EP 40 DI 10.1023/A:1019109407863 PG 6 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA V17SE UT WOS:000207956100006 ER PT J AU Fischer, DA Hu, ZS Hsu, SM AF Fischer, D. A. Hu, Z. S. Hsu, S. M. TI Molecular orientation and bonding of monolayer stearic acid on a copper surface prepared in air SO TRIBOLOGY LETTERS LA English DT Article DE X-ray absorption; stearic acid monolayers; molecular orientation; copper surfaces; tribochemical modification AB The molecular orientation of a monolayer stearic acid, adsorbed on a copper surface in air, was studied by means of Xray absorption spectroscopy above the carbon and oxygen K edges. Carbon-K-edge X-ray absorption measurements were used to quantify the molecular tilt of the alkyl chain from the surface normal, which was found to be 49 and 39 respectively before and after rubbing. Tribochemical bonding chemistry was observed using oxygen-K-edge X-ray absorption measurements. Chemisorbed stearic acid was found to adsorb initially in both monodentate and bidentate sites. The monodentate chemisorbed stearic acid was then transformed to a bidentate surface configuration after tribochemical reaction. Furthermore, spectra from the chemisorbed stearic acid monolayer were similar to the spectrum from a bulk stearic acid powder standard, and the data from the tribochemically modified stearic acid monolayer surface appeared to be identical to that from a bulk cupric stearate. C1 [Fischer, D. A.; Hu, Z. S.; Hsu, S. M.] Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fischer, DA (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 14 TC 17 Z9 17 U1 0 U2 4 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD MAR PY 1997 VL 3 IS 1 BP 41 EP 45 DI 10.1023/A:1019148131061 PG 5 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA V17SE UT WOS:000207956100007 ER PT J AU Hsu, SM AF Hsu, Stephen M. TI Summary report on the research needs and priorities in the tribology of boundary layer lubrication SO TRIBOLOGY LETTERS LA English DT Editorial Material C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hsu, SM (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 1 U2 3 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD MAR PY 1997 VL 3 IS 1 BP 139 EP 140 DI 10.1023/A:1019156400111 PG 2 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA V17SE UT WOS:000207956100020 ER PT J AU Blau, PJ Ludema, KC Rhee, SK Glaeser, WA Ruff, AW Bahadur, S Bayer, RG Rigney, DA Vingsbo, O LarsenBasse, J AF Blau, PJ Ludema, KC Rhee, SK Glaeser, WA Ruff, AW Bahadur, S Bayer, RG Rigney, DA Vingsbo, O LarsenBasse, J TI The birth and history of the International Conferences on Wear of Materials SO WEAR LA English DT Editorial Material AB The International Wear of Materials (WoM) Conference series has experienced a colorful history of changes. from the struggles of its founders and the difficulties of finding suitable publishers for its papers, to the latest organizational experiment in coordinating with another major conference, In the face of minimal technical society support, steadfast efforts by the Steering Committee, enthusiastic volunteers, and a host of international paper solicitors have permitted the conference to survive and even to flourish, Throughout the years, the conference has reflected the trends in materials tribology research and has developed a loyal following. The success of the WoM conference series has flowed directly from the confluence of four basic elements: a special focus on wear of materials, the use of a rigorous review and editing process for all the papers submitted, an organization based on an independent group of tribology researchers with diverse but complementary backgrounds, and, lastly, a willingness to experiment with all aspects of the conference, including the choice of conference sites, sponsoring organizations, and publishers for the proceedings. It is impossible to know what form the WoM conference series will take in 1999 or beyond, While the paper publication situation seems to have been resolved for the moment, who will manage the future conferences has not. Thanks to past efforts, important contributions to understanding and using tribomaterials and to the stimulation of new research on wear-resistant materials are a lingering legacy. It will take the enthusiastic work of many selfless and dedicated individuals to continue the fine traditions established in the first twenty years of WoM. (C) 1997 Elsevier Science S.A. C1 UNIV MICHIGAN,DEPT MECH ENGN,ANN ARBOR,MI 48109. ALLIED SIGNAL BRAKING SYST INC,TROY,MI 48084. BATTELLE MEM INST,COLUMBUS LABS,COLUMBUS,OH 43201. NIST,DIV CERAM,GAITHERSBURG,MD 20899. IOWA STATE UNIV,DEPT MECH ENGN,AMES,IA 50011. OHIO STATE UNIV,COLUMBUS,OH 43210. UPPSALA UNIV,S-75121 UPPSALA,SWEDEN. NATL SCI FDN,ARLINGTON,VA 22230. RP Blau, PJ (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 0 TC 1 Z9 1 U1 1 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD MAR PY 1997 VL 203 BP 1 EP 10 DI 10.1016/S0043-1648(96)07407-8 PG 10 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA WV203 UT WOS:A1997WV20300004 ER PT J AU Ruff, AW Kreider, KG AF Ruff, AW Kreider, KG TI Deposited thin-film wear sensors: Materials and design SO WEAR LA English DT Article; Proceedings Paper CT 11th International Conference on Wear of Materials (WoM 97) CY APR 20-23, 1997 CL SAN DIEGO, CA DE sensor; temperature; thin films; wear sensor AB Vacuum deposited thin-film sensors have been developed for monitoring wear and temperature in a variety of bearing applications. The sensor typically consists of one or more metallic or insulator films. This lamination of sputtered thin-film resistance elements and thermoelectric elements with appropriate insulators is deposited directly on the bearing surface. The thin-film package can be designed to have wear behavior similar to that of the bearing materials, and to have a small surface area that conforms to the bearing contour. The wear sensor monitors the regression of the surface, i.e. the loss of material due to wear, in the range 0.1-10 mu m (or more) over the small area that the sensor occupies. The thermoelectric sensor monitors local temperature. The effect of the materials and fabrication on the properties of the sensors are described as they affect the electrical response and the wear characteristics. Desired properties needed by the conducting film component include adequate electrical conductivity, adhesion to the insulating layers, low ductility, adequate toughness, and hardness. The critical properties of the insulating film component were found to be adhesion, low conductivity, strength, and hardness. Test results were obtained for sliding ring and block tests in both air and oil-lubricated environments. For conducting films, aluminum, platinum, tantalum, and type K+ and K- thermoelectric alloys were studied and are reported here. Copper and two metal silicides were also evaluated. For insulating films, results on aluminum oxide, tantalum oxide, and borosilicate glass are reported. The substrate block material was 304 stainless steel. It was found that the electrical performance of the conducting films in the sensor package can be described using a simple electrical resistance model. (C) 1997 Elsevier Science S.A. RP Ruff, AW (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 11 TC 10 Z9 10 U1 1 U2 7 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD MAR PY 1997 VL 203 BP 187 EP 195 DI 10.1016/S0043-1648(96)07410-8 PG 9 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA WV203 UT WOS:A1997WV20300024 ER PT J AU Aberson, SD AF Aberson, SD TI The prediction of the performance of a nested barotropic hurricane track forecast model SO WEATHER AND FORECASTING LA English DT Article ID SKILL AB Linear multiple regression and discriminant analyses provide estimates of the errors of track forecasts from a nested barotropic hurricane track forecast model(VICBAR), which was run in the North Atlantic Basin during the 1989-94 hurricane seasons. Predictors are determined from the synoptic situation, the magnitude of atmospheric changes in the environment of the tropical cyclone, the consistency between current and past predictions, and the past performance of the model for each particular storm. This technique distinguishes cases in which VICBAR performs well from those for which it performs poorly and can provide skillful operational predictions of model performance to forecasters. RP Aberson, SD (reprint author), NOAA,ATLANTIC OCEANOG & METEOROL LAB,HURRICANE RES DIV,ERL,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Aberson, Sim/C-4891-2013 OI Aberson, Sim/0000-0002-3670-0100 NR 15 TC 7 Z9 7 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD MAR PY 1997 VL 12 IS 1 BP 24 EP 30 DI 10.1175/1520-0434(1997)012<0024:TPOTPO>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ473 UT WOS:A1997WQ47300003 ER PT J AU Young, GS Harlan, JA Georges, TM AF Young, GS Harlan, JA Georges, TM TI Application of over-the-horizon radar observations to synoptic and mesoanalysis over the Atlantic SO WEATHER AND FORECASTING LA English DT Article ID OCEAN; WINDS; WAVES AB Over-the-horizon (OTH) radar observations of surface wind direction offer a high-resolution (15 km) resource for synoptic and mesoscale wind field analysis. With horizontal resolution at the lower end of the mesoscale and areal coverage in the synoptic scale, OTH radar has the potential to contribute significantly to the amelioration of the data sparseness that has long plagued over-ocean surface analysis. Because of a twofold ambiguity in the OTH radar algorithm for determining surface wind direction, however, mapping surface wind directions unambiguously would normally require two radars with overlapping coverage. Alternatively, the single-radar ambiguity can be resolved by combining NWP model analyses and incidental surface wind observations with meteorological insight. An approach to the latter, less expensive solution is presented that relies on the classic principles of streamline analysis and an easy-to-use graphical wind field editor developed specifically for this task. A case study demonstrates the utility of the resulting OTH radar analyses of surface wind direction over the tropical Atlantic Ocean. Existing military OTH radars in several countries could be used for such monitoring with little impact on their primary mission. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. NOAA,ENVIRONM TECHNOL LAB,BOULDER,CO. RP Young, GS (reprint author), PENN STATE UNIV,COLL EARTH & MINERAL SCI,DEPT METEOROL,503 WALKER BLDG,UNIVERSITY PK,PA 16802, USA. NR 23 TC 4 Z9 4 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD MAR PY 1997 VL 12 IS 1 BP 44 EP 55 DI 10.1175/1520-0434(1997)012<0044:AOOTHR>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ473 UT WOS:A1997WQ47300005 ER PT J AU Toth, Z Kalnay, E Tracton, SM Wobus, R Irwin, J AF Toth, Z Kalnay, E Tracton, SM Wobus, R Irwin, J TI A synoptic evaluation of the NCEP ensemble SO WEATHER AND FORECASTING LA English DT Article ID NMC; PREDICTION; FORECASTS; MODEL; SKILL AB Ensemble forecasting has been operational at NCEP (formerly the National Meteorological Center) since December 1992. In March 1994, more ensemble forecast members were added. In the new configuration, 17 forecasts with the NCEP global model are run every day, our to 16-day lead time. Beyond the 3 control forecasts (a T126 and a T62 resolution control at 0000 UTC and a T126 control at 1200 UTC), 14 perturbed forecasts are made at the reduced T62 resolution. Global products from the ensemble forecasts are available from NCEP via anonymous FTP. The initial perturbation vectors are derived from seven independent breeding cycles, where the fast-growing nonlinear perturbations grow freely, apart from the periodic rescaling that keeps their magnitude compatible with the estimated uncertainty within the control analysis. The breeding process is an integral part of the extended-range forecasts, and the generation of the initial perturbations for the ensemble is done at no computational cost beyond that of running the forecasts. A number of graphical forecast products derived from the ensemble are available to the users, including forecasters at the Hydrometeorological Prediction Center and the Climate Prediction Center of NCEP. The products include the ensemble and cluster means, standard deviations, and probabilities of different events. One of the most widely used products is the ''spaghetti'' diagram where a single map contains all 17 ensemble forecasts, as depicted by a selected contour level of a field, for example, 5520 m at 500-hPa height or 50 m s(-1) windspeed at the jet level. With the aid of the above graphical displays and also by objective verification, the authors have established that the ensemble can provide valuable information for both the short and extended range. In particular, the ensemble can indicate potential problems with the high-resolution control that occurs on rare occasions in the short range. Most of the time, the ''cloud'' of the ensemble encompasses the verification, thus providing a set of alternate possible scenarios beyond that of the control. Moreover, the ensemble provides a more consistent outlook for the future. While consecutive control forecasts verifying on a particular date may often display large ''jumps'' from one day to the next, the ensemble changes much less, and its envelope of solutions typically remains unchanged. In addition, the ensemble extends the practical limit of weather forecasting by about a day. For example, significant new weather systems (blocking, extratropical cyclones, etc.) are usually detected by some ensemble members a day earlier than by the high-resolution control. Similarly, the ensemble mean improves forecast skill by a day or more in the medium to extended range, with respect to the skill of the control. The ensemble is also useful in pointing out areas and times where the spread within the ensemble is high and consequently low skill can be expected and, conversely, those cases in which forecasters can make a confident extended-range forecast because the low ensemble spread indicates high predictability. Another possible application of the ensemble is identifying potential model errors. A case of low ensemble spread with all forecasts verifying poorly may be an indication of model bias. The advantage of the ensemble approach is that it can potentially indicate a systematic bias even for a single case, while studies using only a control forecast need to average many cases. RP Toth, Z (reprint author), NCEP,ENVIRONM MODELING CTR,5200 AUTH RD,ROOM 204,CAMP SPRINGS,MD 20746, USA. RI Kalnay, Eugenia/F-4393-2010; Toth, Zoltan/I-6624-2015; OI Toth, Zoltan/0000-0002-9635-9194; Kalnay, Eugenia/0000-0002-9984-9906 NR 33 TC 59 Z9 59 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD MAR PY 1997 VL 12 IS 1 BP 140 EP 153 DI 10.1175/1520-0434(1997)012<0140:ASEOTN>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ473 UT WOS:A1997WQ47300010 ER PT J AU Billet, J DeLisi, M Smith, BG Gates, C AF Billet, J DeLisi, M Smith, BG Gates, C TI Use of regression techniques to predict hail size and the probability of large hail SO WEATHER AND FORECASTING LA English DT Article ID WSR-88D AB Multiple regression and logistic regression equations were derived for the prediction of hail size based on data from 1992 through 1994. The multiple regression equation was formulated to predict hail diameter. The logistic regression equation was developed to predict the probability of hail size greater than or equal to 1.9 cm in diameter. Variables used for this study consisted of vertically integrated liquid (VIL) computed from the Weather Surveillance Radar-1988 Doppler (WSR-88D) radar and convective parameters derived from the skew-T/Hodograph analysis and research program. Data were obtained from the Baltimore, Maryland/Washington D.C., WSR-88D radar and Dulles, Virginia; upper-air soundings. Numerous parameters were tested; however, only VIL, 85-kPa temperature, freezing level, and mean storm-relative inflow in the lowest 2-km were retained for the multiple regression equation. These four parameters were used as a base to derive the logistic regression equation, and this derivation process added no additional terms or interactions to these four terms. Both of the equations were verified using statistical techniques with hail occurrence and diameter data from May 1994 through May 1995. The multiple regression equation was found to be of limited use in predicting hail diameter. However, the logistic regression equation did considerably better in predicting the probability of hail size greater than or equal to 1.9 cm. C1 NATL WEATHER SERV,FORECAST OFF,BALTIMORE,MD. NATL WEATHER SERV,FORECAST OFF,WASHINGTON,DC. NATL WEATHER SERV OFF,NEWPORT,NC. NR 12 TC 30 Z9 30 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD MAR PY 1997 VL 12 IS 1 BP 154 EP 164 DI 10.1175/1520-0434(1997)012<0154:UORTTP>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ473 UT WOS:A1997WQ47300011 ER PT J AU Howard, KW Gourley, JJ Maddox, RA AF Howard, KW Gourley, JJ Maddox, RA TI Uncertainties in WSR-88D measurements and their impacts on monitoring life cycles SO WEATHER AND FORECASTING LA English DT Article AB Radar measurement uncertainties associated with storm top, cloud top, and other height measurements are well recognized; however, the authors feel the resulting impacts on the trends of storm features are not as well documented or understood by some users of the WSR-88D system. Detailed examination of radar-measured life cycles of thunderstorms occurring in Arizona indicates substantial limitations in the WSR-88D's capability to depict certain aspects of storm-height attribute evolution (i.e., life cycle) accurately. These inherent limitations are illustrated using a vertical reflectivity structure model for the life cycle of a simple, ''single-pulse'' thunderstorm. The life cycle of this simple storm is ''scanned'' at varying ranges and translation speeds. The results show that radar-determined trends are often substantially different from those of the model storm and that in extreme cases the radar-detected storm and the model storm can have trends in storm-top height of opposite sign. Caution is clearly required by both the operational and research users of some products derived from operational WSR-88D data. C1 COOPERAT INST MESOSCALE METEOROL STUDIES,NORMAN,OK. RP Howard, KW (reprint author), US DEPT COMMERCE,NOAA,ERL,NATL SEVERE STORMS LAB,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. RI Gourley, Jonathan/C-7929-2016 OI Gourley, Jonathan/0000-0001-7363-3755 NR 8 TC 19 Z9 19 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD MAR PY 1997 VL 12 IS 1 BP 166 EP 174 DI 10.1175/1520-0434(1997)012<0166:UIWMAT>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ473 UT WOS:A1997WQ47300012 ER PT J AU Sichla, T Altorfer, F Hohlwein, D Reimann, K Steube, M Wrzesinski, J Jacobs, H AF Sichla, T Altorfer, F Hohlwein, D Reimann, K Steube, M Wrzesinski, J Jacobs, H TI Crystal structure determination of a strontium hydride imide nitride - Sr-2(H)N/SrNH resp Sr-2(D)N/SrND - By X-ray, neutron, and synchrotron radiation SO ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE LA German DT Article DE strontium hydride imide nitride; preparation; crystal structure determination AB Strontium reacts with nitrogen and hydrogen resp. deuterium under well defined conditions to a phase containing hydride, imide and nitride ions. Sr is evaporated at 1000 degrees C. The Sr vapor reacts with N-2 and H-2 resp. D-2 (p(N-2) = p(H-2/D-2) = 50 mbar) in the gas phase. The product crystallizes as orange-yellow resp. black needles at 800 degrees C. Neither X-ray single crystal nor X-ray and neutron powder diffraction data led to an acceptable model for the crystal structure. A high resolution diffraction experiment with synchrotron radiation gave the needed informations: Splitting of reflections led to a model in R3m with a = 3.870(1) Angstrom and c = 18.958(3) Angstrom. Further split reflections indicate, that the crystals contain areas where SrNH is a second phase besides Sr-2(PI)N. Neutron diffraction data (measured at 2 K, 10 K, 300 K and 505 K) were interpreted by a two phase model with Sr-2(D)N/SrND: In a slightly distorted cubic close packing of Sr-atoms hydride and nitride resp. imide ions occupy each by one third octahedral sites fully and in an ordered way. C1 UNIV DORTMUND,LEHRSTUHL ANORGAN CHEM 1,FACHBEREICH CHEM,D-44221 DORTMUND,GERMANY. NIST,GAITHERSBURG,MD 20899. UNIV TUBINGEN,INST KRISTALLOG,D-7400 TUBINGEN,GERMANY. HAHN MEITNER INST BERLIN GMBH,BENSC,D-1000 BERLIN,GERMANY. UNIV DORTMUND,FACHBEREICH PHYS,DORTMUND,GERMANY. RI Reimann, Klaus/B-8824-2009 OI Reimann, Klaus/0000-0003-4290-0659 NR 14 TC 13 Z9 13 U1 0 U2 2 PU JOHANN AMBROSIUS BARTH VERLAG PI HEIDELBERG PA IM WEIHER 10, D-69121 HEIDELBERG, GERMANY SN 0044-2313 J9 Z ANORG ALLG CHEM JI Z. Anorg. Allg. Chem. PD MAR PY 1997 VL 623 IS 3 BP 414 EP 422 DI 10.1002/zaac.19976230166 PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA WL731 UT WOS:A1997WL73100012 ER PT J AU Nagy, VY Komozin, PN Desrosiers, MF AF Nagy, VY Komozin, PN Desrosiers, MF TI Choosing reference samples for EPR concentration measurements .3. Systems of S=3/2 SO ANALYTICA CHIMICA ACTA LA English DT Article DE electron paramagnetic resonance (EPR) spectrometry; reference samples; reference materials; signal intensity; transition probability; accuracy AB The papers of this series provide tabulated values that characterize the specific intensity of electron paramagnetic resonance (EPR) spectrometric signals (signal area per paramagnetic center) for a wide range of paramagnetic species of various classes. These data enable one to choose a reference material producing an EPR signal close in specific intensity to the signal of the species to be quantitated in the unknown or to determine a correction factor when the specific intensities of the two signals are substantially different. The tabulated values comprise transition probabilities and the derivatives of the resonance fields with respect to frequency obtained by exact diagonalization of spin Hamiltonian matrices; they can be used in field-swept X-band EPR quantitations of solids, This part covers the S=3/2 paramagnetic centers in cubic, axial, and orthorhombic crystal fields. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Nagy, VY (reprint author), VI VERNADSKII INST GEOCHEM & ANALYT CHEM,19 KOSYGIN ST,MOSCOW 117975,RUSSIA. NR 9 TC 5 Z9 5 U1 1 U2 3 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 28 PY 1997 VL 339 IS 1-2 BP 31 EP 51 DI 10.1016/S0003-2670(96)00469-2 PG 21 WC Chemistry, Analytical SC Chemistry GA WL898 UT WOS:A1997WL89800003 ER PT J AU Nagy, VY Sokolov, DP Desrosiers, MF AF Nagy, VY Sokolov, DP Desrosiers, MF TI Choosing reference samples for EPR concentration measurements .4. Systems of S=5/2 SO ANALYTICA CHIMICA ACTA LA English DT Article DE electron paramagnetic resonance (EPR) spectrometry; reference samples; reference materials; signal intensity; transition probability; accuracy AB The papers of this series provide tabulated values that characterize the specific intensity of electron paramagnetic resonance (EPR) signals (signal area per paramagnetic center) for a wide range of paramagnetic species of various classes. These data enable one to choose a reference material producing an EPR signal close in specific intensity to the signal of the species to be quantitated in the unknown or to determine a correction factor when the specific intensities of the two signals are substantially different. The tabulated values comprise transition probabilities and the derivatives of the resonance fields with respect to frequency obtained by exact diagonalization of spin Hamiltonian matrices; they can be used in field-swept X-band EPR quantitations of solids. This part covers the S=5/2 paramagnetic centers in cubic and some axial crystal fields. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Nagy, VY (reprint author), VI VERNADSKII INST GEOCHEM & ANALYT CHEM,19 KOSYGIN ST,MOSCOW 117975,RUSSIA. NR 10 TC 3 Z9 3 U1 0 U2 2 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 28 PY 1997 VL 339 IS 1-2 BP 53 EP 62 DI 10.1016/S0003-2670(96)00470-9 PG 10 WC Chemistry, Analytical SC Chemistry GA WL898 UT WOS:A1997WL89800004 ER PT J AU Bushnell, PG Steffensen, JF Brill, RW Jones, DR AF Bushnell, PG Steffensen, JF Brill, RW Jones, DR TI Macromolecular capillary permeability of three species of fish. SO FASEB JOURNAL LA English DT Meeting Abstract C1 INDIANA UNIV,DEPT BIOL,S BEND,IN 46634. UNIV COPENHAGEN,MARINE BIOL LAB,HELSINGOR,DENMARK. NMFS,HONOLULU LAB,NOAA,HONOLULU,HI 96822. UNIV BRITISH COLUMBIA,DEPT ZOOL,VANCOUVER,BC V6T 2A9,CANADA. RI Steffensen, John/F-6778-2010 OI Steffensen, John/0000-0002-4477-8039 NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1997 VL 11 IS 3 BP 558 EP 558 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA WL530 UT WOS:A1997WL53000558 ER PT J AU Ravishankara, AR Rudich, Y Talukdar, R Barone, SB AF Ravishankara, AR Rudich, Y Talukdar, R Barone, SB TI Oxidation of atmospheric reduced sulphur compounds: Perspective from laboratory studies SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES LA English DT Article ID DIMETHYL SULFIDE; OH RADICALS; KINETICS; MECHANISM; SULFUR; CH3S; IO; EMISSIONS; SURFACES; CLIMATE AB Results of laboratory experiments which address the course of the OH+DMS (dimethyl sulphide) reaction in the atmosphere are presented. It is shown that OH reacts via a complex sequence of reactions to produce CH3S and other products, and argued that NO3 is unlikely to be an important oxidizer of DMS in the marine boundary layer because it is very efficiently taken up by water droplets. A simplified mechanism for the oxidation of DMS in the troposphere is presented. This mechanism explains some of the field observations on the end products of DMS oxidation and their variations with temperature. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Ravishankara, AR (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Rudich, Yinon/K-1498-2012; TALUKDAR, RANAJIT/G-4530-2013; Ravishankara, Akkihebbal/A-2914-2011; OI TALUKDAR, RANAJIT/0000-0001-6017-8431; Rudich, Yinon/0000-0003-3149-0201 NR 44 TC 66 Z9 67 U1 1 U2 12 PU ROYAL SOC LONDON PI LONDON PA 6 CARLTON HOUSE TERRACE, LONDON, ENGLAND SW1Y 5AG SN 0962-8436 J9 PHILOS T ROY SOC B JI Philos. Trans. R. Soc. Lond. Ser. B-Biol. Sci. PD FEB 28 PY 1997 VL 352 IS 1350 BP 171 EP 181 PG 11 WC Biology SC Life Sciences & Biomedicine - Other Topics GA WM317 UT WOS:A1997WM31700008 ER PT J AU Cox, RA Hewitt, N Toumi, R Ayres, GP AF Cox, RA Hewitt, N Toumi, R Ayres, GP TI Field measurements of dimethyl sulphide and its oxidation products in the atmosphere - Discussion SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES LA English DT Editorial Material C1 UNIV LONDON,IMPERIAL COLL,LONDON WC1E 7HU,ENGLAND. CSIRO,DIV ATMOSPHER RES,MORDIALLOC,VIC 3195,AUSTRALIA. NOAA,AERON LAB,BOULDER,CO 80303. RP Cox, RA (reprint author), UNIV CAMBRIDGE,CAMBRIDGE CB2 1TN,ENGLAND. NR 0 TC 0 Z9 0 U1 1 U2 1 PU ROYAL SOC LONDON PI LONDON PA 6 CARLTON HOUSE TERRACE, LONDON, ENGLAND SW1Y 5AG SN 0962-8436 J9 PHILOS T ROY SOC B JI Philos. Trans. R. Soc. Lond. Ser. B-Biol. Sci. PD FEB 28 PY 1997 VL 352 IS 1350 BP 188 EP 189 PG 2 WC Biology SC Life Sciences & Biomedicine - Other Topics GA WM317 UT WOS:A1997WM31700011 ER PT J AU Ravishankara, AR Slingo, A Liss, PS Wolff, E Shine, KP AF Ravishankara, AR Slingo, A Liss, PS Wolff, E Shine, KP TI Climate model studies of sulphate aerosols and clouds - Discussion SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES LA English DT Editorial Material C1 UNIV E ANGLIA,NORWICH NR4 7TJ,NORFOLK,ENGLAND. BRITISH ANTARCTIC SURVEY,CAMBRIDGE,ENGLAND. UNIV READING,READING RG6 2AH,BERKS,ENGLAND. RP Ravishankara, AR (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI LISS, Peter/A-8219-2013; Ravishankara, Akkihebbal/A-2914-2011; Shine, Keith/D-9093-2012 OI Shine, Keith/0000-0003-2672-9978 NR 0 TC 0 Z9 0 U1 0 U2 2 PU ROYAL SOC LONDON PI LONDON PA 6 CARLTON HOUSE TERRACE, LONDON, ENGLAND SW1Y 5AG SN 0962-8436 J9 PHILOS T ROY SOC B JI Philos. Trans. R. Soc. Lond. Ser. B-Biol. Sci. PD FEB 28 PY 1997 VL 352 IS 1350 BP 228 EP 229 PG 2 WC Biology SC Life Sciences & Biomedicine - Other Topics GA WM317 UT WOS:A1997WM31700019 ER PT J AU Han, Y Shaw, JA Churnside, JH Brown, PD Clough, SA AF Han, Y Shaw, JA Churnside, JH Brown, PD Clough, SA TI Infrared spectral radiance measurements in the tropical Pacific atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB Downwelling thermal infrared emission from the tropical atmosphere is affected strongly by the typically large amounts of water vapor. In two experiments within the last 2 years we have used a Fourier transform spectroradiometer to measure tropical atmospheric emission, concentrating on the ''window'' region between about 800 and 1200 cm(-1). Shortly after the first of these experiments, substantial differences between measured and calculated radiances led to the development of a new water vapor continuum model. This model subsequently has been incorporated into several widely distributed radiative transfer codes (LBLRTM, MODTRAN, FASCODE). Measurements from the second tropical experiment, which occurred during March and April 1996, validate this new continuum model. This is an important comparison because the new measurements were taken with an improved instrument under better defined clear-sky conditions than the original tropical data on which the continuum correction was based. Model residuals are of the order of the uncertainty in measurements, especially of the atmospheric water vapor and temperature profiles. C1 NOAA, ENVIRONM TECHNOL LAB, BOULDER, CO 80303 USA. ATMOSPHER & ENVIRONM RES INC, CAMBRIDGE, MA 02139 USA. RP Han, Y (reprint author), UNIV COLORADO, NOAA,ENVIRONM RES LAB, COOPERAT INST RES ENVIRONM SCI,325 BROADWAY, R-E-ETL, BOULDER, CO 80303 USA. RI Han, Yong/F-5590-2010; Churnside, James/H-4873-2013 OI Han, Yong/0000-0002-0183-7270; NR 7 TC 50 Z9 53 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 1997 VL 102 IS D4 BP 4353 EP 4356 DI 10.1029/96JD03717 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WL278 UT WOS:A1997WL27800011 ER PT J AU Roitberg, AE Gerber, RB Ratner, MA AF Roitberg, AE Gerber, RB Ratner, MA TI A vibrational eigenfunction of a protein: Anharmonic coupled-mode ground and fundamental excited states of BPTI SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PANCREATIC TRYPSIN-INHIBITOR; NEUTRON-SCATTERING ANALYSIS; CONSISTENT-FIELD APPROACH; FORCE-FIELD; MOLECULAR-DYNAMICS; CONFIGURATIONAL ENTROPY; MACROMOLECULES; CONFORMATIONS; SIMULATIONS; MYOGLOBIN AB We present detailed methodology and results for the approximate calculation of the anharmonic vibrational wave functions for a given structure of a protein. The ground state and the fundamental vibrationally excited states of hydrated BPTI are computed with an approach that is of very good accuracy for low-lying states. The eigenfunctions are used to predict quantum properties such as vibrational excitation frequencies and IR intensities as well as atomic mean square displacements at T = 0 K. The method treats diagonal anharmonic effects exactly up to fourth order in normal mode coordinates, while using a mean-field approximation, the vibrational self-consistent field (SCF) approximation for the mode-mode couplings. The inclusion of the diagonal effects (exact in fourth order) makes the potentials stiffer than quadratic. When the mode-mode coupling is included as a mean field, the system becomes even stiffer. These effects produce significant modifications of such observables as the vibrational spectrum and Debye-Waller factors. The results presented here should be considered essentially exact except for potentially important approximations: (a) that the potential energy used bears some resemblance to reality, (b) that the system is restricted to a single minimum in the potential energy surface, and (c) that the quartic expansion in normal modes, when truncated to fourth order, provides a good description of the potential. These issues will be addressed in the main text. The results show that the vibrational absorption spectrum is strongly affected by anharmonic and mode-mode coupling effects. Deviations from the corresponding harmonic absorption intensities are very large. Unlike our previous study that found only weak mode-mode coupling effects for the lowest 100 modes, the SCF corrections calculated here for the intermediate frequency modes are seen to be very significant. The results have important implications for the vibrational spectroscopy and other properties of proteins at low temperatures. C1 HEBREW UNIV JERUSALEM,DEPT PHYS CHEM,IL-91904 JERUSALEM,ISRAEL. HEBREW UNIV JERUSALEM,FRITZ HABER RES CTR MOL DYNAM,IL-91904 JERUSALEM,ISRAEL. UNIV CALIF IRVINE,DEPT CHEM,IRVINE,CA 92717. NORTHWESTERN UNIV,DEPT CHEM,EVANSTON,IL 60208. RP Roitberg, AE (reprint author), NATL INST STAND & TECHNOL,DIV BIOTECHNOL,222-A353,GAITHERSBURG,MD 20899, USA. RI Roitberg, Adrian/A-2378-2009 NR 41 TC 38 Z9 39 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD FEB 27 PY 1997 VL 101 IS 9 BP 1700 EP 1706 DI 10.1021/jp9629194 PG 7 WC Chemistry, Physical SC Chemistry GA WL357 UT WOS:A1997WL35700030 ER PT J AU Chen, CY Cohen, RM Simons, DS Chi, PH AF Chen, CY Cohen, RM Simons, DS Chi, PH TI Fermi energy pinning at the surface during growth of n- and p-type GaAs SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; PHASE EPITAXY; PRESSURE; ZN; DIETHYLZINC; DIFFUSION AB The Te donor concentration has been used as a probe to infer the surface carrier concentration during growth by organometallic vapor phase epitaxy. With the partial pressure of Te held constant during the growth of an npn structure, the Te concentration is found to remain nearly unchanged across the p-n junctions. This result is used to show that the carrier concentration at the growing surface shifts by a negligible amount as the growth is switched between n- and p-type GaAs. When combined with previous results for p-type GaAs, we conclude that the Fermi energy at the (100)-oriented surface remains pinned between 100 and 200 meV below the intrinsic Fermi energy, independent of the type or the concentration of dopant used. (C) 1997 American Institute of Physics. C1 NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. RP Chen, CY (reprint author), UNIV UTAH,DEPT MAT SCI & ENGN,SALT LAKE CITY,UT 84112, USA. NR 11 TC 0 Z9 0 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 24 PY 1997 VL 70 IS 8 BP 1005 EP 1007 DI 10.1063/1.118474 PG 3 WC Physics, Applied SC Physics GA WJ626 UT WOS:A1997WJ62600030 ER PT J AU Sobolewski, MA AF Sobolewski, MA TI Experimental test of models of radio-frequency plasma sheaths SO APPLIED PHYSICS LETTERS LA English DT Article ID CAPACITIVE RF SHEATH; ELECTRODE SHEATHS; PARALLEL-PLATE; REFERENCE CELL; DISCHARGES; REACTOR; ARGON; POWER AB The ion current and sheath impedance were measured at the radio-frequency-powered electrode of an asymmetric, capacitively coupled plasma reactor, for discharges in argon at 1.33-133 Pa. The measurements were used to test the models of the radio frequency sheath derived by Lieberman [IEEE Trans. Plasma Sci. 17, 338 (1989)] and Godyak and Sternberg [Phys. Rev. A 42, 2299 (1990)], and establish the range of pressure and sheath voltage in which they are valid. (C) 1997 American Institute of Physics. RP Sobolewski, MA (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 13 TC 16 Z9 16 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 24 PY 1997 VL 70 IS 8 BP 1049 EP 1051 DI 10.1063/1.118464 PG 3 WC Physics, Applied SC Physics GA WJ626 UT WOS:A1997WJ62600045 ER PT J AU Wang, H Kesani, PK Balsara, NP Hammouda, B AF Wang, H Kesani, PK Balsara, NP Hammouda, B TI Undulations and disorder in block copolymer lamellae under shear flow SO MACROMOLECULES LA English DT Article ID STYRENE-ISOPRENE-STYRENE; A PHASE-TRANSITION; DIBLOCK COPOLYMER; POLYSTYRENE-POLYISOPRENE; MICROPHASE SEPARATION; TRIBLOCK COPOLYMER; ORDER; MICROSTRUCTURE; ALIGNMENT; INSTABILITIES AB The effect of shear flow on a concentrated block copolymer solution with lamellar microstructure was studied by in-situ small angle neutron scattering. Microstructural changes were determined from scattering measurements in all three principal directions (flow, velocity gradient, and neutral directions). The lamellae were found to align along the velocity direction but exhibited two orientations: one parallel to the shearing surfaces and the other perpendicular to the shearing surfaces. The perfection of the perpendicular alignment was always significantly greater than that of the parallel alignment. In fact, our sample in the parallel alignment was, to a large extent, disordered (i.e., liquidlike). In some cases, we found transient, well-aligned, perpendicular lamellae that eventually degenerated to poorly ordered, parallel lamellae. In one case, a systematic increase in lamellar undulations was evident prior to disordering. These results are not in agreement with current theories, which only predict enhanced order in block copolymers under shear flow. C1 POLYTECH INST NEW YORK,DEPT CHEM ENGN,METROTECH CTR 6,BROOKLYN,NY 11201. NIST,GAITHERSBURG,MD 20899. NR 46 TC 43 Z9 43 U1 2 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD FEB 24 PY 1997 VL 30 IS 4 BP 982 EP 992 DI 10.1021/ma961269z PG 11 WC Polymer Science SC Polymer Science GA WK315 UT WOS:A1997WK31500040 ER PT J AU Weida, MJ Nesbitt, DJ AF Weida, MJ Nesbitt, DJ TI High resolution mid-infrared spectroscopy of ArH2O: The v(2) bend region of H2O SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACE; WEAKLY-BOUND COMPLEX; LASER SPECTROSCOPY; VANDERWAALS BONDS; AR-H2O; ROTATION; VIBRATION; DYNAMICS; PREDISSOCIATION; STABILIZATION AB Six internal rotation/vibration bands of ArH2O are observed in a slit supersonic expansion via direct absorption of a tunable diode laser in the upsilon(2) bend region of H2O. The spectra obtained for the ortho H2O manifold are well represented by a pseudodiatomic model with nearly free internal rotation of the H2O subunit. By way of contrast, the para bands show significant mixing between the internal rotor and stretch states, indicative of strong angular-radial coupling in the intermolecular potential. The spectra for the para Ar-H2O species can be deperturbed based on a three state Coriolis plus angular-radial coupling model which includes microwave, far-ir and near-ir data. The results indicate a redshift of approximate to 0.58 cm(-1) upon bend excitation of the H2O subunit, and in general rather modest changes in the excited state intermolecular potential from the ground state potential. No indication of predissociation broadening is found, and the instrument-limited linewidths place a lower limit on the vibrational lifetime in the excited state of tau greater than or equal to 7.2(6) ns. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Weida, MJ (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 22 TC 38 Z9 38 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 22 PY 1997 VL 106 IS 8 BP 3078 EP 3089 DI 10.1063/1.473051 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WH843 UT WOS:A1997WH84300010 ER PT J AU Romanik, K AF Romanik, K TI Directed rectangle-visibility graphs have unbounded dimension SO DISCRETE APPLIED MATHEMATICS LA English DT Article ID REPRESENTATIONS AB Visibility representations of graphs map vertices to sets in Euclidean space and express edges as visibility relations between these sets. One visibility representation in the plane that has been studied is one in which the vertices of the graph map to closed isothetic rectangles and the edges are expressed by horizontal or vertical visibility between the rectangles. Two rectangles are only considered to be visible to one another if there is a nonzero width horizontal or vertical band of sight between them. A graph that can be represented in this way is called a rectangle-visibility graph. A rectangle-visibility graph can be directed by directing all edges towards the positive x and y directions, which yields a directed acyclic graph. A directed acyclic graph G has dimension d if d is the minimum integer such that the vertices of G can be ordered by d linear orderings, <(l),..., <(d), and for vertices u and v there is a directed path from u to v if and only if u <(i) v for all 1 less than or equal to i less than or equal to d. In this note we show that the dimension of the class of directed rectangle-visibility graphs is unbounded. C1 NIST,INTELLIGENT SYST DIV,GAITHERSBURG,MD 20899. RP Romanik, K (reprint author), UNIV MARYLAND,CTR AUTOMAT RES,COLLEGE PK,MD 20742, USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-218X J9 DISCRETE APPL MATH JI Discret Appl. Math. PD FEB 21 PY 1997 VL 73 IS 1 BP 35 EP 39 DI 10.1016/S0166-218X(96)00075-3 PG 5 WC Mathematics, Applied SC Mathematics GA WK586 UT WOS:A1997WK58600006 ER PT J AU Bryan, K AF Bryan, K TI Ocean circulation theory - Pedlosky,J SO SCIENCE LA English DT Book Review RP Bryan, K (reprint author), PRINCETON UNIV, PROGRAM ATMOSPHER & OCEAN SCI, PRINCETON, NJ 08542 USA. NR 1 TC 0 Z9 0 U1 1 U2 1 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 21 PY 1997 VL 275 IS 5303 BP 1076 EP 1076 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WJ503 UT WOS:A1997WJ50300028 ER PT J AU Eickhoff, ML Hall, JL AF Eickhoff, ML Hall, JL TI Real-time precision refractometry: New approaches SO APPLIED OPTICS LA English DT Article ID UPDATED EDLEN EQUATION; REFRACTIVE-INDEX; AIR; SHIFTS AB We introduce two new approaches for near-real-time, high-precision tracking of the refractive index of the ambient atmosphere. The methods can be realized at low cost and are expected to have important practical application in those accurate dimensional metrology applications employing interferometry in air. A valuable potential application is the control of step-and-repeat mask positioning for integrated circuit production in which temporal stability time scales over days can be crucial. Extension of the methods to absolute index measurement is discussed. (C) 1997 Optical Society of America. C1 UNIV COLORADO, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. NATL INST STAND & TECHNOL, BOULDER, CO USA. NATL INST STAND & TECHNOL, QUANTUM PHYS DIV, BOULDER, CO 80303 USA. NR 26 TC 21 Z9 21 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 20 PY 1997 VL 36 IS 6 BP 1223 EP 1234 DI 10.1364/AO.36.001223 PG 12 WC Optics SC Optics GA WH289 UT WOS:A1997WH28900020 PM 18250795 ER PT J AU Borrmann, S Solomon, S Dye, JE Baumgardner, D Kelly, KK Chan, KR AF Borrmann, S Solomon, S Dye, JE Baumgardner, D Kelly, KK Chan, KR TI Heterogeneous reactions on stratospheric background aerosols, volcanic sulfuric acid droplets, and type I polar stratospheric clouds: Effects of temperature fluctuations and differences in particle phase SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SITU MEASUREMENTS; GROWTH; REMOVAL; HNO3 AB Northern hemispheric ER-2 (NASA) data from stratospheric aerosol measurements during background conditions, periods disturbed by the influence of Mount Pinatubo, ana polar stratospheric cloud (PSC) type I events are used to study the heterogeneous reactions of ClONO2 with H2O and of HOCl and ClONO2 with HCl in comparison to the gas phase reaction rate of OH with HCl. To calculate the reaction rates, the measured data of pressure, temperature, water vapor, and aerosol surface are utilized together with recent laboratory results for the heterogeneous reactive uptake coefficients. Because observations are limited, the mixing ratios of the gas phase species entering these rate calculations (i.e., ClONO2, HOCl, HCl, and N2O5) are taken from a two-dimensional model. It is found that in dense volcanic clouds at temperatures below 200 K the resulting heterogeneous reaction rates of chlorine activation can be of similar magnitude as the gas phase reaction rate. The heterogeneous rates in PSCs can exceed the gas phase fates by more than 2 orders of magnitude. For the ClONO2 and HOCl reactions the measured aerosol surfaces during the PSC events are treated both as liquid (e.g., ternary solution) droplets and: as solid NAT to compare the effects of the different phases. The reaction rates on NAT are significantly lower than on liquid droplets. Indeed, this study shows that a transition from liquid ternary solutions to NAT is expected to reduce the rate of chlorine activation based on present chemical understanding and on observed aerosol surface areas, Additionally, the effect of temperature and surface area fluctuations on the heterogeneous reaction rates is discussed. C1 NOAA, AERON LAB, BOULDER, CO 80303 USA. NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Borrmann, S (reprint author), UNIV MAINZ, INST ATMOSPHER PHYS, BECHERWEG 21, D-55099 MAINZ, GERMANY. RI Borrmann, Stephan/E-3868-2010 NR 16 TC 32 Z9 37 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 1997 VL 102 IS D3 BP 3639 EP 3648 DI 10.1029/96JD02976 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WK266 UT WOS:A1997WK26600010 ER PT J AU Harder, JW Brault, JW Johnston, PV Mount, GH AF Harder, JW Brault, JW Johnston, PV Mount, GH TI Temperature dependent NO2 cross sections at high spectral resolution SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERIC NO2; EQUILIBRIUM-CONSTANT; NITROGEN-DIOXIDE; MCMURDO-STATION; ABSORPTION-SPECTROSCOPY; VISIBLE SPECTROSCOPY; NM REGION; ANTARCTICA; N2O4; O-3 AB The importance of nitrogen dioxide in both the troposphere and the stratosphere has been known for some years, and since the early 1970s, spectroscopic determinations have played an important role in understanding NOx chemistry. Spectroscopic measurements of the atmosphere have improved in quality in recent years to the point that an accurate determination of the NO2 absorption cross section is essential to accurate retrievals of not only NO2 but also less abundant species in the troposphere and stratosphere. NO2 is such a large absorber (approximately 1% at large air mass) in the stratosphere at twilight or in the troposphere under even mildly polluted conditions, that if it is not properly removed from observed spectra, the spectra of the more subtle species are masked and cannot be measured at all. We present cross sections of NO2 in the spectral region 350-585 nm at four temperatures between 217 and 298, K and total pressures between 100 and 600 torr at a mixing ratio of 84.1 ppmv and at a spectral resolution sufficient for accurate convolution with instruments typically used to measure atmospheric NO2. Data will be presented to demonstrate the presence of NO2 pressure dependence in high resolution. A detailed comparison with commonly used literature cross sections is made to show how such instrument parameters as wavelength accuracy, resolution, spectrograph scattered light, and data sampling affect the usefulness of the observed cross section. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Harder, JW (reprint author), NOAA, AERON LAB, ENVIRONM RES LABS, 325 BROADWAY, BOULDER, CO 80303 USA. NR 50 TC 123 Z9 125 U1 1 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 FEB 20 PY 1997 VL 102 IS D3 BP 3861 EP 3879 DI 10.1029/96JD03086 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WK266 UT WOS:A1997WK26600025 ER PT J AU Tuck, A AF Tuck, A TI Introduction to special section: ASHOE/MAESA SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material RP Tuck, A (reprint author), NOAA, R-E-AL6, 325 BROADWAY, BOULDER, CO 80303 USA. RI Tuck, Adrian/F-6024-2011 OI Tuck, Adrian/0000-0002-2074-0538 NR 0 TC 1 Z9 1 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 FEB 20 PY 1997 VL 102 IS D3 BP 3899 EP 3899 DI 10.1029/96JD03920 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WK266 UT WOS:A1997WK26600028 ER PT J AU Tuck, AF Brune, WH Hipskind, RS AF Tuck, AF Brune, WH Hipskind, RS TI Airborne Southern Hemisphere Ozone Experiment Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/MAESA): A road map SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB ASHOE/MAESA used instruments aboard the ER-2 aircraft to study transport, photochemistry, radiation, and microphysics in the lower stratosphere over a range of seasons and latitudes. During the period from February tp November 1994 the ER-2 aircraft flew the suite of instruments between 60 degrees N and 70 degrees S in the longitude sector 115 degrees W to 160 degrees E. Of the 45 flights, 28 were entirely in the southern hemisphere between March and October, 6 were from Hawaii, 2 crossed the tropics between Hawaii and Fiji, and the remainder were from northern California. Data from these and associated ground-based, balloon-borne, and satellite instruments were combined with a variety of operational and research meteorological models to guide the flight planning and to interpret the results. The scientific rationale for the mission is given and the aircraft payload listed. A synopsis of the flights is supplied. C1 PENN STATE UNIV, DEPT METEOROL, UNIVERSITY PK, PA 16802 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Tuck, AF (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E AL 6, BOULDER, CO 80303 USA. RI Tuck, Adrian/F-6024-2011 OI Tuck, Adrian/0000-0002-2074-0538 NR 1 TC 21 Z9 21 U1 1 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 20 PY 1997 VL 102 IS D3 BP 3901 EP 3904 DI 10.1029/96JD02745 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WK266 UT WOS:A1997WK26600029 ER PT J AU Gao, RS Fahey, DW Salawitch, RJ Lloyd, SA Anderson, DE Demajistre, R McElroy, CT Woodbridge, EL Wamsley, RC Donnelly, SG DelNegro, LA Proffitt, MH Stimpfle, RM Kohn, DW Kawa, R Lait, LR Loewenstein, M Podolske, JR Keim, ER Dye, JE Wilson, JC Chan, KR AF Gao, RS Fahey, DW Salawitch, RJ Lloyd, SA Anderson, DE Demajistre, R McElroy, CT Woodbridge, EL Wamsley, RC Donnelly, SG DelNegro, LA Proffitt, MH Stimpfle, RM Kohn, DW Kawa, R Lait, LR Loewenstein, M Podolske, JR Keim, ER Dye, JE Wilson, JC Chan, KR TI Partitioning of the reactive nitrogen reservoir in the lower stratosphere of the southern hemisphere: Observations and modeling SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IN-SITU MEASUREMENTS; ANTARCTIC OZONE HOLE; INSITU MEASUREMENTS; ER-2 AIRCRAFT; SULFURIC-ACID; 72-DEGREES-S LATITUDE; SUPERSONIC AIRCRAFT; VOLCANIC AEROSOLS; CHLORINE RADICALS; SULFATE AEROSOLS AB Measurements of nitric oxide (NO), nitrogen dioxide (NO2), and total reactive nitrogen (NOy = NO + NO2 + NO3 + HNO3 + ClONO2 + 2N(2)O(5) + ...) were made during austral fall, winter, and spring 1994 as part of the NASA Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft mission. Comparisons between measured NO2 values and those calculated using a steady state (SS) approximation are presented for flights at mid and high latitudes. The SS results agree with the measurements to within 8%, suggesting that the kinetic rate coefficients and calculated NO2 photolysis rate used in the SS approximation are reasonably accurate for conditions in the lower stratosphere. However, NO2 values observed in the Concorde exhaust plume were significantly less than SS values. Calculated NO2 photolysis rates showed good agreement with values inferred from solar flux measurements, indicating a strong self-consistency in our understanding of UV radiation transmission in the lower stratosphere. Model comparisons using a full diurnal, photochemical steady state model also show good agreement with the NO and NO2 measurements, suggesting that the reactions affecting the partitioning of the NOy reservoir are well understood in the lower stratosphere. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MD 20723 USA. ATMOSPHER ENVIRONM SERV, DOWNSVIEW, ON M3H 5T4, CANADA. UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, LA JOLLA, CA 92093 USA. UNIV COLORADO, DEPT CHEM & BIOCHEM, BOULDER, CO 80309 USA. HARVARD UNIV, DEPT CHEM, CAMBRIDGE, MA 02138 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NATL CTR ATMOSPHER RES, MMM, BOULDER, CO 80307 USA. UNIV DENVER, DEPT ENGN, DENVER, CO 80208 USA. RP Gao, RS (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E-AL6, BOULDER, CO 80303 USA. RI Salawitch, Ross/B-4605-2009; Kawa, Stephan/E-9040-2012; 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 60 TC 48 Z9 48 U1 2 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 1997 VL 102 IS D3 BP 3935 EP 3949 DI 10.1029/96JD01967 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WK266 UT WOS:A1997WK26600032 ER PT J AU Hassanzadeh, P Irikura, KK AF Hassanzadeh, P Irikura, KK TI Nearly ab initio thermochemistry: The use of reaction schemes. Application to IO and HOI SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LEVEL-CORRELATED CALCULATIONS; MOLECULAR ELECTRIC PROPERTIES; POLARIZED BASIS-SETS; EFFECTIVE CORE POTENTIALS; OZONE DEPLETION; PHOTOELECTRON-SPECTROSCOPY; THERMODYNAMIC PROPERTIES; EQUILIBRIUM-CONSTANT; GAUSSIAN-2 THEORY; HOBR AB Reaction energetics from ab initio calculations are almost always combined with experimental data to derive enthalpies of formation. Some popular strategies are discussed, and a simple criterion is suggested for estimating the accuracy to be expected from using an arbitrary reaction, We recommend using more than one reaction scheme whenever possible and suggest how the results from different reactions may be combined in a weighted average. The uncertainties of the derived values can be estimated from the averaging procedure and by comparing the results obtained using different basis sets and treatments of electron correlation. As examples, we compute the gas-phase thermochemistry for IO-, IO, IO+, and HOI. As a check, analogous calculations are also done for the corresponding bromine species. Finally, we recommend that appropriate experimental data be exploited whenever they are expected to be more accurate than their theoretical counterparts. While compiling the auxiliary data to support these calculations, we found that recent measurements require that the experimental enthalpies of formation of many molecules be revised. We present values for HOCl, HOBr, Cl2O, and Br2O. C1 NIST,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 NR 68 TC 40 Z9 40 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 20 PY 1997 VL 101 IS 8 BP 1580 EP 1587 DI 10.1021/jp963011g PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WL095 UT WOS:A1997WL09500024 ER PT J AU Head, MS Given, JA Gilson, MK AF Head, MS Given, JA Gilson, MK TI ''Mining minima'': Direct computation of conformational free energy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MOLECULAR-DYNAMICS; GENETIC ALGORITHMS; BINDING-ENERGIES; SIMULATIONS; INHIBITORS; DESIGN; MINIMIZATION; PARAMETERS; PREDICTION; SILICALITE AB We describe a novel, two-step method for directly computing the conformational free energy of a molecule. In the first step, a finite set of low-energy conformations is identified, and its contribution to the configuration integral is evaluated by a straightforward Monte Carlo technique. The method of finding energy minima incorporates certain features of the global-underestimator method and of a genetic algorithm. In the second step, the contribution to the configuration integral due to conformations not included in the initial integration is determined by Metropolis Monte Carlo sampling. Applications to alanine oligopeptides and to three cyclic urea inhibitors of HIV protease are presented. C1 NIST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NR 47 TC 98 Z9 99 U1 1 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 20 PY 1997 VL 101 IS 8 BP 1609 EP 1618 DI 10.1021/jp963817g PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WL095 UT WOS:A1997WL09500028 ER PT J AU Webb, RS Rind, DH Lehman, SJ Healy, RJ Sigman, D AF Webb, RS Rind, DH Lehman, SJ Healy, RJ Sigman, D TI Influence of ocean heat transport on the climate of the Last Glacial Maximum SO NATURE LA English DT Article ID NORTH-ATLANTIC; SURFACE-TEMPERATURE; ICE-AGE; WATER CIRCULATION; RECONSTRUCTIONS; MODEL; DEEP; RECORD AB A series of climate simulations using an atmospheric general circulation model shows that maintaining ocean heat transport at close to present-day values, but with otherwise glacial boundary conditions, leads to an enhanced cooling, particularly in the tropics. This is in agreement with recent geochemical evidence from fossil corals, ground waters, and ice. Near-modern ocean heat transport may have been sustained in all ocean basins during the Last Glacial Maximum in order to balance the formation and export of Glacial North Atlantic Intermediate Water. C1 NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. UNIV COLORADO,DEPT GEOL SCI,BOULDER,CO 80309. UNIV COLORADO,INSTAAR,BOULDER,CO 80309. WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543. RP Webb, RS (reprint author), NOAA,NATL GEOPHYS DATA CTR,PALEOCLIMATOL PROGRAM,325 BROADWAY,BOULDER,CO 80303, USA. RI Sigman, Daniel/A-2649-2008; Healy, Richard/J-9214-2015 OI Sigman, Daniel/0000-0002-7923-1973; Healy, Richard/0000-0002-5098-8921 NR 44 TC 121 Z9 126 U1 0 U2 9 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 20 PY 1997 VL 385 IS 6618 BP 695 EP 699 DI 10.1038/385695a0 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WJ423 UT WOS:A1997WJ42300037 ER PT J AU Beary, ES Paulsen, PJ Jassie, LB Fassett, JD AF Beary, ES Paulsen, PJ Jassie, LB Fassett, JD TI Determination of environmental lead using continuous-flow microwave digestion isotope dilution inductively coupled plasma mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID CERTIFICATION AB A commercial now-through microwave system was successfully applied as an alternative sample preparation procedure for lead determinations using isotope dilution inductively coupled plasma quadrupole mass spectrometry, Sample is introduced as a slurry and then injected into a carrier stream which is continually flowing through the system, As configured, the sample dissolution is sequential, taking about 10 min/sample. This closed system is easy to use and produces lon blanks, thus providing a viable alternative to the direct introduction of untreated samples, which can degrade analytical results, Leaves, air filters, urine, sludge, dust, and paint standard reference materials previously certified for lead using isotope dilution mass spectrometry (IDMS) were used to evaluate the accuracy of this automated sample preparation device. Lead concentrations in the nanograms to micrograms per gram range were accurately determined when compared with the certified value and previous IDMS results. C1 CEM CORP,MATTHEWS,NC 28106. RP Beary, ES (reprint author), NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 32 TC 40 Z9 41 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD FEB 15 PY 1997 VL 69 IS 4 BP 758 EP 766 DI 10.1021/ac9606923 PG 9 WC Chemistry, Analytical SC Chemistry GA WH357 UT WOS:A1997WH35700035 ER PT J AU Kiselev, SB AF Kiselev, SB TI Prediction of the thermodynamic properties and the phase behavior of binary mixtures In the extended critical region SO FLUID PHASE EQUILIBRIA LA English DT Article DE binary mixtures; critical phenomena; crossover equation of state; dilute aqueous solutions; phase behavior; thermodynamic properties; methane; ethane; n-butane; sodium chloride ID LIQUID-VAPOR RELATIONS; CRITICAL-POINT; CRITICAL-TEMPERATURE; SINGLE-COMPONENT; SYSTEM NACL-H2O; FLUID MIXTURES; HEAT-CAPACITY; DILUTE NACL; METHANE; CROSSOVER AB A new parametric crossover equation of state for pure fluids and binary mixtures, which incorporates the scaling laws asymptotically close to the critical point and is transformed into the regular classical expansion far away from the critical point, is proposed. A comparison is made with the experimental data for pure methane, ethane and n-butane, and for binary mixtures of methane and ethane, and of ethane and n-butane. The equation of state yields a satisfactory representation of the thermodynamic properly data in a large range of temperatures and densities. An application for dilute aqueous sodium chloride solutions is also discussed. C1 RUSSIAN ACAD SCI,INST OIL & GAS RES,MOSCOW 117917,RUSSIA. RP Kiselev, SB (reprint author), NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,325 BROADWAY,BOULDER,CO 80303, USA. NR 62 TC 50 Z9 51 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 15 PY 1997 VL 128 IS 1-2 BP 1 EP 28 DI 10.1016/S0378-3812(96)03173-1 PG 28 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA WN310 UT WOS:A1997WN31000001 ER PT J AU Karcher, B Fahey, DW AF Karcher, B Fahey, DW TI The role of sulfur emission in volatile particle formation in jet aircraft exhaust plumes SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Recent in-situ emission measurements of the Concorde in the lower stratosphere point to a surprisingly efficient conversion of fuel sulfur to H2SO4 in the exhaust plume. By means of a comprehensive model, the formation and evolution of aerosol particles and precursors are calculated in the diluting aircraft wake. The results provide strong evidence that high levels of SO3 present in the nascent plume are required to explain the observations of large numbers of nanometer-sized aerosols. Limiting particle formation at emission to keep potential chemical effects on stratospheric ozone small will require control of the sulfur oxidation kinetics during fuel combustion. The similarities between super- and subsonic exhaust plumes suggest that the presence of SO3 in the latter will also be a key limiting factor in new aerosol production. C1 NOAA,AERON LAB,BOULDER,CO 80303. RP Karcher, B (reprint author), UNIV MUNICH,HOHENBACHERNSTR 22,D-85354 FREISING,GERMANY. RI Karcher, Bernd/D-5325-2014; Fahey, David/G-4499-2013 OI Karcher, Bernd/0000-0003-0278-4980; Fahey, David/0000-0003-1720-0634 NR 16 TC 35 Z9 35 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 15 PY 1997 VL 24 IS 4 BP 389 EP 392 DI 10.1029/97GL00119 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WJ181 UT WOS:A1997WJ18100010 ER PT J AU Wiegand, S Sengers, JMHL Zhang, KJ Briggs, ME Gammon, RW AF Wiegand, S Sengers, JMHL Zhang, KJ Briggs, ME Gammon, RW TI Discrepancies in turbidity measurements in the ionic binary mixture triethyl n-hexyl ammonium triethyl n-hexyl boride in diphenyl ether SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CRITICAL EXPONENTS; MICELLAR SOLUTIONS; CONSOLUTE POINT AB We have repeated and extended turbidity measurements on a new sample of the ionic mixture triethyl n-hexyl ammonium triethyl n-hexyl boride (N2226B2226) in diphenyl ether in a temperature range above its consolute point. Previous measurements on this system by some of us indicated mean-field critical behavior over the range of reduced temperatures 10(-4)2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WK941 UT WOS:A1997WK94100004 ER PT J AU Butterfield, DA Jonasson, IR Massoth, GJ Feely, RA Roe, KK Embley, RE Holden, JF McDuff, RE Lilley, MD Delaney, JR AF Butterfield, DA Jonasson, IR Massoth, GJ Feely, RA Roe, KK Embley, RE Holden, JF McDuff, RE Lilley, MD Delaney, JR TI Seafloor eruptions and evolution of hydrothermal fluid chemistry SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article ID DE-FUCA RIDGE; EAST PACIFIC RISE; VENT FLUIDS; VOLCANIC-ERUPTION; COAXIAL SEGMENT; MIDOCEAN RIDGE; DIKE INJECTION; AXIAL VOLCANO; EVENT; PLUMES AB A major challenge confronting geochemists is to relate the chemistry of vented hydrothermal fluids to the local or regional tectonic and volcanic state of mid-ocean ridges. After more than 15 years of sampling submarine hydrothermal fluids, a complex picture of spatial and temporal variability in temperature and composition is emerging. Recent time-series observations and sampling of ridge segments with confirmed recent volcanic eruptions (CoAxial and North Cleft on the Juan de Fuca ridge and 9-10 degrees N on the East Pacific Rise) have created a first-order understanding of how hydrothermal systems respond to volcanic events on the seafloor. Phase separation and enhanced volatile fluxes are associated with volcanic eruptions, with vapour-dominated fluids predominating in the initial post-eruption period, followed in time by brine-dominated fluids, consistent with temporary storage of brine below the seafloor. Chemical data for CoAxial vents presented here are consistent with this evolution. Rapid changes in output and composition of hydrothermal fluids following volcanic events may have a profound effect on microbiological production, macrofaunal colonization, and hydrothermal heat and mass fluxes. Size and location of the heat source are critical in determining how fast heat is removed and whether subseafloor microbial production will flourish. CoAxial event plumes may be a direct result of dyking and eruption of lavas on the seafloor. C1 GEOL SURVEY CANADA, OTTAWA, ON, CANADA. NOAA, PACIFIC MARINE ENVIRONM LAB, SEATTLE, WA 98115 USA. NOAA, PACIFIC MARINE ENVIRONM LAB, NEWPORT, OR 97365 USA. UNIV WASHINGTON, SCH OCEANOG, SEATTLE, WA 98195 USA. RP Butterfield, DA (reprint author), UNIV WASHINGTON, JOINT INST STUDY ATMOSPHERE & OCEANS, SEATTLE, WA 98195 USA. RI Holden, James/E-6815-2013; Butterfield, David/H-3815-2016 OI Butterfield, David/0000-0002-1595-9279 NR 38 TC 153 Z9 155 U1 4 U2 45 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD FEB 15 PY 1997 VL 355 IS 1723 BP 369 EP 386 DI 10.1098/rsta.1997.0013 PG 18 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WK209 UT WOS:A1997WK20900009 ER PT J AU Stiles, MD AF Stiles, MD TI Generalized Slater-Koster method for fitting band structures SO PHYSICAL REVIEW B LA English DT Article ID TIGHT-BINDING; TRANSITION-METALS; PHONON AB A tight-binding procedure is presented for fitting electronic band structures of crystals. It is based on a fully automated method of determining all possible independent matrix elements for arbitrary crystal structures. A fit, using this method, for the band structure of hexagonal close-packed Tc is more than an order of magnitude better than previous fits. RP Stiles, MD (reprint author), NIST,ELECTRON PHYS GRP,GAITHERSBURG,MD 20899, USA. RI Stiles, Mark/K-2426-2012 OI Stiles, Mark/0000-0001-8238-4156 NR 19 TC 4 Z9 4 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1997 VL 55 IS 7 BP 4168 EP 4173 DI 10.1103/PhysRevB.55.4168 PG 6 WC Physics, Condensed Matter SC Physics GA WK493 UT WOS:A1997WK49300037 ER PT J AU Saeta, PN Gallagher, AC AF Saeta, PN Gallagher, AC TI Photoluminescence properties of silicon quantum-well layers SO PHYSICAL REVIEW B LA English DT Article ID POROUS SILICON; VISIBLE LUMINESCENCE; AMORPHOUS-SILICON; NANOCRYSTALLINE SILICON; ULTRATHIN CRYSTALLINE; OPTICAL-PROPERTIES; BLUE LUMINESCENCE; SI-SIO2 INTERFACE; SI CRYSTALLITES; LIGHT-EMISSION AB Nanometer-scale crystal silicon films surrounded by SiO2 were prepared by oxidizing silicon-on-insulator substrates prepared from SIMOX (separation by implantation of oxygen) and crystallized hydrogenated amorphous silicon films. Average silicon layer thickness was determined from reflection spectra. When sufficiently thin (< 2 nm), all layers emitted red photoluminescence under blue and UV cw excitation, with a spectrum that did not depend on the mean layer thickness. The spectrum was roughly Gaussian with a peak energy of 1.65 eV, which is lower than for most porous silicon spectra. The time scale for the luminescence decay was similar to 35 mu s at room temperature and similar to 54 mu s at 88 K; the decay was nonexponential and did not exhibit spectral diffusion. Atomic force microscope images of the silicon layers showed that luminescing layers were broken apart into regions similar to 50-100 mu m in diameter, suggesting that luminescence comes only from regions small enough to have no nonradiative recombination centers in the band gap. These results an inconsistent with a simple quantum-confinement model for luminescence in two-dimensional silicon and suggest the importance of radiation from surface states. C1 UNIV COLORADO, JILA, BOULDER, CO 80309 USA. NIST, QUANT PHYS DIV, BOULDER, CO 80309 USA. NR 59 TC 39 Z9 41 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1997 VL 55 IS 7 BP 4563 EP 4574 DI 10.1103/PhysRevB.55.4563 PG 12 WC Physics, Condensed Matter SC Physics GA WK493 UT WOS:A1997WK49300087 ER PT J AU Hoobler, RJ Opansky, BJ Leone, SR AF Hoobler, RJ Opansky, BJ Leone, SR TI Low-temperature rate coefficients for reactions of ethynyl radical (C2H) with propane, isobutane, n-butane, and neopentane SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TITANS ATMOSPHERE; RATE CONSTANTS; PHOTOCHEMISTRY; HYDROCARBONS; CHEMISTRY; ACETYLENE AB Low-temperature rate coefficients for the reactions of C2H + RH --> products (RH = C3H8, i-C4H10, n-C4H10, and neo-C5H12) have been measured over the temperature range 154-361. K. Measurements were made using laser photolysis of C2H2 to produce C2H. Transient infrared laser absorption decays of C2H are used to monitor the subsequent reaction in a transverse flow eel. The results show that the rate coefficients for the reactions of C2H with propane are independent of temperature while the rate coefficients for the reactions of C2H with isobutane, n-butane, and neopentane have a negative temperature dependence. Over the experimental temperature range, the rate constants for C2H + RH fit the following Arrhenius expressions: k(propane) = (7.8 +/- 0.4) x 10(-11) exp[(3 +/- 12)/T], k(isobutane) = (8.7 +/- 0.8) x 10(-11) exp[(28 +/- 21)/T], k(n-butane) = s(-1). The corresponding rate constants at 298 K are k(propane) = 7.9 x 10(-11), k(isobutane) = 9.6 x 10(-11), k(n-butane) = 1.2 x 10(-10), k(neopentane) = 1.1 X 10(-10) cm(3) molecules(-1) s(-1). C1 NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NR 26 TC 26 Z9 26 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 13 PY 1997 VL 101 IS 7 BP 1338 EP 1342 DI 10.1021/jp963286w PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WL092 UT WOS:A1997WL09200024 ER PT J AU Wenthold, PG Kim, JB Lineberger, WC AF Wenthold, PG Kim, JB Lineberger, WC TI Photoelectron spectroscopy of m-xylylene anion SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GROUND-STATE; RESONANCE SPECTROSCOPY; ABINITIO CALCULATIONS; ACTIVATION-ENERGY; ELECTRON-AFFINITY; M-QUINODIMETHANE; TRIPLET-STATE; RING-CLOSURE; TRIMETHYLENEMETHANE; PHOTODETACHMENT AB The 351-nm photoelectron spectrum of the negative ion of 1,3-benzoquinodimethane (m-xylylene) is reported. Features are observed in the photoelectron spectrum corresponding to formation of the B-3(2), (1)A(1), and B-1(2) states of m-xylylene. The electron affinity of the triplet ground state is found to be 0.919 +/- 0.008 eV, and vibrational frequencies of 290, 540, and 1500 cm(-1) are obtained. The active modes are assigned to alpha-carbon bending, ring deformation, and methylene bending, respectively. The (1)A(1) state is found to lie 9.6 +/- 0.2 kcal/mol higher in energy than the ground state, in good agreement with theoretical predictions. Vibrational frequencies of 265, 1000, and 1265 cm(-1) are found for this state. The B-1(2) is estimated to be <21.5 kcal/mol higher in energy than the ground state. Density functional calculations have been carried out on the negative ion, indicating that the B-2(1) ion is a minimum on the potential energy surface, lying 2.9 kcal/mol lower in energy than the (2)A(2) ion, which is a transition state. C1 UNIV COLORADO,NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Wenthold, PG (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 52 TC 87 Z9 87 U1 2 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 12 PY 1997 VL 119 IS 6 BP 1354 EP 1359 DI 10.1021/ja9623830 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA WH326 UT WOS:A1997WH32600022 ER PT J AU Chapman, WB Weida, MJ Nesbitt, DJ AF Chapman, WB Weida, MJ Nesbitt, DJ TI Scattering dynamics in HF+He, Ne, and Ar: State-to-state cross sections, Dopplerimetry, and alignment measurement via direct infrared laser absorption in crossed supersonic jets SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ROTATIONALLY INELASTIC-COLLISIONS; MOLECULAR-BEAM SCATTERING; POTENTIAL-ENERGY SURFACE; HE-HF COLLISIONS; DIFFERENTIAL SCATTERING; DOUBLE-RESONANCE; SPECTRAL INTENSITIES; EXCITATION; PREDISSOCIATION; ARGON AB Absolute state-to-state cross sections are reported for rotationally inelastic scattering in crossed jets of HF with He, Ne, and Ar at mean center-of-mass collision energies of 480, 390, and 350 cm(-1), respectively. HF seeded in Ar diluent gas is cooled into the J=0 ground rotational state in a pulsed supersonic expansion, followed by single collision rotational excitation with rare gas atoms from a second pulsed supersonic jet. The column-integrated densities of HF in both the initial and final scattering slates are probed in the jet intersection region via direct absorption of light from a narrow bandwidth (0.0001 cm(-1)), continuously tunable, color center laser. Total inelastic cross sections for collisional loss out of J=0 and collisional excitation into J>0 states are determined in absolute units from the dependence of infrared absorption signals on collider gas concentration, Full close coupling scattering calculations are performed on several ab initio and empirical potential energy surfaces for each of the three HF+rare gas systems. Agreement for He+HF and Ar+HF integral cross sections is remarkably goad, but significant discrepancies are noted for the less accurately determined Ne+HF surface, Photoelastic polarization modulation of the IR laser is used to probe for rotational alignment in the scattered HF flux; the measurements set an upper polarizance limit for collisionally populated J=1 HF molecules [probed on P(1)] of /P/<2%. High resolution IR laser Doplerimetry reveals velocity structure in the collisionally excited J=1 Doppler profiles, which is in excellent qualitative agreement with theoretical predictions of rainbow features in the J=1<--0 state-to-state differential cross section. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Chapman, WB (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 89 TC 33 Z9 38 U1 2 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 1997 VL 106 IS 6 BP 2248 EP 2264 DI 10.1063/1.473787 PG 17 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WG307 UT WOS:A1997WG30700022 ER PT J AU Lindner, J Lundberg, JK Lovejoy, CM Leone, SR AF Lindner, J Lundberg, JK Lovejoy, CM Leone, SR TI Translational to vibrational and rotational (T->V,R) energy transfer and reactive exchange collisions of H(D)+HF(DF) in the energy range from 1 to 2 eV by time-resolved Fourier transform spectroscopy SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DOUBLE-RESONANCE MEASUREMENTS; MECHANICAL REACTION PROBABILITIES; CROSSED MOLECULAR-BEAM; F + D2; TRANSITION-STATE; F+H-2 REACTION; FTIR EMISSION; PHOTODISSOCIATION DYNAMICS; TEMPERATURE-DEPENDENCE; RATE COEFFICIENTS AB The product state distributions for hot atom collisions of H(D) with HF(DF) with a broad range of collision energies between 1.2 eV and 2.3 eV are measured with time-resolved Fourier transform spectroscopy and rotational resolution under multiple collision conditions. In most cases the vibrational distributions of reactive and nonreactive channels can be distinguished, All rotational distributions have a similar appearance with a maximum at J=5 and an additional pronounced higher component, which cannot be described by a single Boltzmann distribution. The results are compared with recent three dimensional quasiclassical trajectory calculations (accompanying paper by Schatz) by applying a multiple collision model for both the H(D) atom slowdown and the rotational and vibrational relaxation. The rotational distributions can also be interpreted by a three dimensional asymmetric breathing ellipsoid model. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. UNIV COLORADO,NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NR 59 TC 11 Z9 11 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 1997 VL 106 IS 6 BP 2265 EP 2276 DI 10.1063/1.473149 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WG307 UT WOS:A1997WG30700023 ER PT J AU Gu, DF Philander, SGH AF Gu, DF Philander, SGH TI Interdecadal climate fluctuations that depend on exchanges between the tropics and extratropics SO SCIENCE LA English DT Article ID UPPER-OCEAN; VARIABILITY; PACIFIC AB The unexpected and prolonged persistence of warm conditions over the tropical Pacific during the early 1990s can be attributed to an interdecadal climate fluctuation that involves changes in the properties of the equatorial thermocline arising as a result of an influx of water with anomalous temperatures from higher latitudes, The influx affects equatorial sea-surface temperatures and hence the tropical and extratropical winds that in turn affect the influx, A simple model demonstrates that these processes can give rise to continual interdecadal oscillations. RP PRINCETON UNIV, DEPT GEOSCI, PROGRAM ATMOSPHER & OCEAN SCI, POB CN710, SAYRE HALL, PRINCETON, NJ 08544 USA. NR 21 TC 669 Z9 738 U1 4 U2 44 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD FEB 7 PY 1997 VL 275 IS 5301 BP 805 EP 807 DI 10.1126/science.275.5301.805 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WG777 UT WOS:A1997WG77700052 ER PT J AU Bush, ABG AF Bush, ABG TI Numerical simulation of the cretaceous tethys circumglobal current SO SCIENCE LA English DT Article ID UPPER-OCEAN; VARIABILITY; PACIFIC AB Certain paleobiogeographical reconstructions of ocean currents during the Cretaceous (about 144 to 65 million years ago) suggest that a circumglobal tropical current flowed westward through the continental configuration of that time. Although some numerical climate models failed in initial attempts to simulate this current, simulations with a coupled atmosphere-ocean model with relatively high spatial resolution and a late Cretaceous continental distribution show that a circumglobal current is a robust feature even though local surface currents in the Tethys Seaway reverse during the south Eurasian monsoon months. RP PRINCETON UNIV, ATMOSPHER & OCEAN SCI PROGRAM, POB CN710, SAYRE HALL, PRINCETON, NJ 08544 USA. NR 21 TC 43 Z9 46 U1 1 U2 6 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD FEB 7 PY 1997 VL 275 IS 5301 BP 807 EP 810 DI 10.1126/science.275.5301.807 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WG777 UT WOS:A1997WG77700053 ER PT J AU Jin, DS Matthews, MR Ensher, JR Wieman, CE Cornell, EA AF Jin, DS Matthews, MR Ensher, JR Wieman, CE Cornell, EA TI Temperature-dependent damping and frequency shifts in collective excitations of a dilute Bose-Einstein condensate SO PHYSICAL REVIEW LETTERS LA English DT Article ID ATOMS; TRAP AB We extend to finite temperature the study of collective excitations of a Bose-Einstein condensate in a dilute gas of Rb-87. Measurements of two modes with different angular momenta show unexpected temperature-dependent frequency shifts, with very different behavior for the two symmetries; in addition there is a sharp feature in the temperature dependence of one mode. The damping of these excitations exhibits dramatic temperature dependence, with condensate modes at temperatures near the transition damping even faster than analogous noncondensate oscillations. C1 UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. RP Jin, DS (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,QUANTUM PHYS DIV,BOULDER,CO 80309, USA. NR 22 TC 318 Z9 322 U1 4 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 3 PY 1997 VL 78 IS 5 BP 764 EP 767 DI 10.1103/PhysRevLett.78.764 PG 4 WC Physics, Multidisciplinary SC Physics GA WG702 UT WOS:A1997WG70200003 ER PT J AU Xia, YN McClelland, JJ Gupta, R Qin, D Zhao, XM Sohn, LL Celotta, RJ Whitesides, GM AF Xia, YN McClelland, JJ Gupta, R Qin, D Zhao, XM Sohn, LL Celotta, RJ Whitesides, GM TI Replica molding using polymeric materials: A practical step toward nanomanufacturing SO ADVANCED MATERIALS LA English DT Article ID SCANNING TUNNELING MICROSCOPE; ATOMIC-FORCE MICROSCOPE; FABRICATION; NANOSTRUCTURES C1 HARVARD UNIV,DEPT CHEM & CHEM BIOL,CAMBRIDGE,MA 02138. NIST,ELECT PHYS GRP,GAITHERSBURG,MD 20899. PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. RI Qin, Dong/E-1434-2011; McClelland, Jabez/A-2358-2015; Xia, Younan/E-8499-2011 OI McClelland, Jabez/0000-0001-5672-5965; NR 21 TC 191 Z9 195 U1 3 U2 26 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA POSTFACH 10 11 61, D-69451 WEINHEIM, GERMANY SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD FEB PY 1997 VL 9 IS 2 BP 147 EP 149 DI 10.1002/adma.19970090211 PG 3 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA WH746 UT WOS:A1997WH74600009 ER PT J AU Manabe, S AF Manabe, S TI Early development in the study of greenhouse warming: The emergence of climate models SO AMBIO LA English DT Article ID GENERAL-CIRCULATION MODEL; RADIATIVE-CONVECTIVE MODEL; GLOBAL CLIMATE; CO2 CONCENTRATION; SENSITIVITY; OCEAN; ATMOSPHERE; GASES AB Following the pioneering contributions of Arrhenius, Callendar and others, climate models emerged as a very promising tool for the study of greenhouse warming. In the early 1960s, a one-dimensional, radiative-convective equilibrium model was developed as the first step towards the development of a three-dimensional model of climate. Incorporating not only the radiative but also the convective heat exchange between the earth's surface and the atmosphere, the model overcame the difficulty encountered by the earlier approach of surface radiative heat balance in estimating the magnitude of greenhouse warming. By the 1970s, a three-dimensional, general circulation model (GCM) of the atmosphere, coupled to a very idealized ocean of swamp-like wet surface, had been used for studies of greenhouse warming. Despite many drastic simplifications, the GCM was very effective for elucidating the physical mechanisms that control global warming and served as a stepping stone towards the use of more comprehensive, coupled ocean-atmosphere GCMs for the study of this problem. RP Manabe, S (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,PRINCETON,NJ 08542, USA. NR 27 TC 37 Z9 37 U1 1 U2 4 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0044-7447 J9 AMBIO JI Ambio PD FEB PY 1997 VL 26 IS 1 BP 47 EP 51 PG 5 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA WM532 UT WOS:A1997WM53200009 ER PT J AU VanDolah, FM Leighfield, TA Haynes, BL Hampson, DR Ramsdell, JS AF VanDolah, FM Leighfield, TA Haynes, BL Hampson, DR Ramsdell, JS TI A microplate receptor assay for the amnesic shellfish poisoning toxin, domoic acid, utilizing a cloned glutamate receptor SO ANALYTICAL BIOCHEMISTRY LA English DT Article ID PERFORMANCE LIQUID-CHROMATOGRAPHY; MUSSELS C1 UNIV TORONTO,FAC PHARM,TORONTO,ON,CANADA. RP VanDolah, FM (reprint author), US NATL MARINE FISHERIES SERV,CHARLESTON LAB,MARINE BIOTOXINS PROGRAM,CHARLESTON,SC 29412, USA. NR 10 TC 62 Z9 63 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD FEB 1 PY 1997 VL 245 IS 1 BP 102 EP 105 DI 10.1006/abio.1996.9889 PG 4 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA WE924 UT WOS:A1997WE92400014 PM 9025975 ER PT J AU Anderson, GW Kub, FJ Carruthers, TF Papanicolaou, NA Frankel, MY Katzer, DS Modolo, JA Tseng, WF AF Anderson, GW Kub, FJ Carruthers, TF Papanicolaou, NA Frankel, MY Katzer, DS Modolo, JA Tseng, WF TI Planar, Al0.3Ga0.7As-passivated-base, heterojunction bipolar phototransistors SO APPLIED OPTICS LA English DT Article DE heterojunction phototransistors; photodetectors; photodetector arrays; optical processing; optoelectronics; GaAs/AlGaAs materials systems AB New planar GaAs heterojunction bipolar phototransistors have been designed and demonstrated. The devices use a GaAs/Al0.3Ga0.7As molecular-beam-epitaxy materials system with an Al0.3Ga0.7As passivated, 10-nm-thick base; a depleted, high-low emitter; and a low emitter-base capacitance. Electrical contact to the emitter is made by a set of parallel, ohmic fingers and to the collector by an ohmic contact formed in a large, approximate to 1.48-mu m deep via. Rise times in response to impulse optical excitation at 810 nm were 747-891 ps except at the two lowest optical excitation powers measured. Photocurrent gains measured at 810 and 850 nm were 0.67-19, depending on experimental conditions. These devices are promising for use in heterodyne photodetector arrays for coherent optical processing channelizers requiring a 100-MHz bandwidth. C1 NIST,GAITHERSBURG,MD 20899. RP Anderson, GW (reprint author), USN,RES LAB,WASHINGTON,DC 20375, USA. RI Katzer, D. Scott/N-7841-2013 NR 12 TC 0 Z9 0 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 1 PY 1997 VL 36 IS 4 BP 760 EP 764 DI 10.1364/AO.36.000760 PG 5 WC Optics SC Optics GA WF061 UT WOS:A1997WF06100002 PM 18250735 ER PT J AU Gauck, H Gfroerer, TH Renn, MJ Cornell, EA Bertness, KA AF Gauck, H Gfroerer, TH Renn, MJ Cornell, EA Bertness, KA TI External radiative quantum efficiency of 96% from a GaAs/GaInP heterostructure SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article AB GaAs/GaInP double heterostructures are index matched with ZnSe hemispheres to increase the coupling of photoluminescence out of the device. We measure external quantum efficiencies as large as 96% at room temperature using a bolometric calibration technique. When the carriers are optically injected near the bandgap energy, the luminescence is blueshifted by up to 1.4 kT. In this case, external efficiencies exceeding 97.5% would yield optical refrigeration in the solid state. C1 UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. NR 9 TC 92 Z9 94 U1 1 U2 8 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD FEB PY 1997 VL 64 IS 2 BP 143 EP 147 DI 10.1007/s003390050455 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA WJ518 UT WOS:A1997WJ51800004 ER PT J AU Aust, JF Booksh, KS Stellman, CM Parnas, RS Myrick, ML AF Aust, JF Booksh, KS Stellman, CM Parnas, RS Myrick, ML TI Precise determination of percent cure of epoxide polymers and composites via fiber-optic Raman spectroscopy and multivariate analysis SO APPLIED SPECTROSCOPY LA English DT Article DE fiber-optic Raman; multivariate analysis, principal component analysis AB A method for real-time determination of the percent cure of epoxies via in situ fiber-optic Raman spectroscopy has been developed. This method utilizes a probe design developed for real-time monitoring of polymer curing and multivariate analysis to interpret the data and determine percent cure. This method was demonstrated to be reliable to +/-0.54% of cure in laboratory samples over a 50-99% cure range. A preliminary study measuring cure percentage in an industrial, glass-reinforced composite has been shown to be reliable to +/-0.82% in the 40-90% cure range. C1 UNIV S CAROLINA,DEPT CHEM & BIOCHEM,COLUMBIA,SC 29208. NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. OI Myrick, Michael/0000-0002-6905-0925 NR 22 TC 27 Z9 29 U1 1 U2 2 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD FEB PY 1997 VL 51 IS 2 BP 247 EP 252 DI 10.1366/0003702971939956 PG 6 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA WM533 UT WOS:A1997WM53300015 ER PT J AU McKinnell, S Thomson, AJ Black, EA Wing, BL Guthrie, CM Koerner, JF Helle, JH AF McKinnell, S Thomson, AJ Black, EA Wing, BL Guthrie, CM Koerner, JF Helle, JH TI Atlantic salmon in the North Pacific SO AQUACULTURE RESEARCH LA English DT Article ID SALAR L; POPULATIONS; SIZE AB The first catches of Atlantic salmon, Salmo salar L., in British Columbia (BC) waters occurred in 1987. The first reported escape of Atlantic salmon (2000 individuals) occurred in 1988. From 1988 to 1995, 97 799 Atlantic salmon were reported escaped from net pens in BC but the true number was higher as not all escapes are reported. Since 1987 a total of 9096 Atlantic salmon was caught in the coastal marine waters of BC, Washington and Alaska, and 188 were caught in fresh water. Most catches occurred in the Johnstone Strait area, where the abundance of salmon farms is highest. The most distant recovery occurred in 1994 when an Atlantic salmon was caught near the western end of the Alaska Peninsula. There have been no reports of successful reproduction of Atlantic salmon in the wild and no feral juveniles have been found. Atlantic salmon caught in the ocean in BC have substantial amounts of adipose tissue and they are heavier at length than fish caught in Alaska. The proportion of fish with prey items in their stomachs is generally low but higher in Alaska (13.1%) than in BC (5.8%). Most fish caught in fresh water are either maturing or mature. C1 MINIST AGR FISHERIES & FOOD,VICTORIA,BC,CANADA. NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,AUKE BAY LAB,JUNEAU,AK. ALASKA DEPT FISH & GAME,KETCHIKAN,AK. RP McKinnell, S (reprint author), FISHERIES & OCEANS CANADA,PACIFIC BIOL STN,NANAIMO,BC V9R 5K6,CANADA. NR 32 TC 23 Z9 28 U1 2 U2 17 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 1355-557X J9 AQUAC RES JI Aquac. Res. PD FEB PY 1997 VL 28 IS 2 BP 145 EP 157 PG 13 WC Fisheries SC Fisheries GA WV298 UT WOS:A1997WV29800007 ER PT J AU Druzhko, AB Weetall, HH AF Druzhko, AB Weetall, HH TI Photoinduced transformation of 4-keto-bacteriorhodopsin gelatin films based on both wild type and D96N mutant SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1997 VL 72 IS 2 BP MAMJ6 EP MAMJ6 PN 2 PG 1 WC Biophysics SC Biophysics GA WE747 UT WOS:A1997WE74700079 ER PT J AU Braha, O Walker, B Cheley, S Kasianowicz, J Hobaugh, MR Song, LZ Gouaux, JE Bayley, H AF Braha, O Walker, B Cheley, S Kasianowicz, J Hobaugh, MR Song, LZ Gouaux, JE Bayley, H TI Structure-based design of a heteromeric transmembrane protein pore. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 WORCESTER FDN EXPT BIOL INC,SHREWSBURY,MA 01545. NIST,GAITHERSBURG,MD 20899. COLUMBIA UNIV,NEW YORK,NY 10032. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1997 VL 72 IS 2 BP TUP10 EP TUP10 PN 2 PG 1 WC Biophysics SC Biophysics GA WE747 UT WOS:A1997WE74700787 ER PT J AU Forbes, JG Schwarz, FP Amann, KJ Ervasti, JM AF Forbes, JG Schwarz, FP Amann, KJ Ervasti, JM TI Comparison of the thermodynamics of binding of myosin S1 and the N-terminus of dystrophin to F-actin. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV MARYLAND,DEPT CHEM & BIOCHEM,COLLEGE PK,MD 20742. NIST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. UNIV WISCONSIN,DEPT PHYSIOL,MADISON,WI 53706. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1997 VL 72 IS 2 BP TH232 EP TH232 PN 2 PG 1 WC Biophysics SC Biophysics GA WE747 UT WOS:A1997WE74702208 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 Distinct and sensitive detection of heavy-metal divalent cations using a genetically engineered ion channel SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. INDIANA UNIV,BLOOMINGTON,IN 47405. WORCESTER FDN BIOMED RES,WORCESTER,MA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1997 VL 72 IS 2 BP THAM7 EP THAM7 PN 2 PG 1 WC Biophysics SC Biophysics GA WE747 UT WOS:A1997WE74701909 ER PT J AU Meuse, CW Plant, AL AF Meuse, CW Plant, AL TI Construction and characterization of phospholipid-alkanethiol hybrid bilayer membranes. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20899. NR 0 TC 1 Z9 1 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1997 VL 72 IS 2 BP TU416 EP TU416 PN 2 PG 1 WC Biophysics SC Biophysics GA WE747 UT WOS:A1997WE74701200 ER PT J AU Head, MS Given, JA Gilson, MK AF Head, MS Given, JA Gilson, MK TI ''Mining minima'': Direct computation of conformational free energy SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NIST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1997 VL 72 IS 2 BP WP437 EP WP437 PN 2 PG 1 WC Biophysics SC Biophysics GA WE747 UT WOS:A1997WE74701848 ER PT J AU Kasianowicz, JJ Bezrukov, SM AF Kasianowicz, JJ Bezrukov, SM TI pH sensitivity of PEG-induced effects on S-aureus alpha-hemolysin single channel current SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. NIH,BETHESDA,MD 20892. NR 0 TC 0 Z9 0 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1997 VL 72 IS 2 BP WP101 EP WP101 PN 2 PG 1 WC Biophysics SC Biophysics GA WE747 UT WOS:A1997WE74701512 ER PT J AU Krueger, S Plant, A Meuse, K Majkrzak, CF Dura, J AF Krueger, S Plant, A Meuse, K Majkrzak, CF Dura, J TI Neutron reflectivity studies of peptides in biomimetic bilayer membranes supported on planar substrates. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20899. RI Dura, Joseph/B-8452-2008 OI Dura, Joseph/0000-0001-6877-959X NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1997 VL 72 IS 2 BP WPME3 EP WPME3 PN 2 PG 1 WC Biophysics SC Biophysics GA WE747 UT WOS:A1997WE74701389 ER PT J AU Velden, CS Hayden, CM Nieman, SJ Menzel, WP Wanzong, S Goerss, JS AF Velden, CS Hayden, CM Nieman, SJ Menzel, WP Wanzong, S Goerss, JS TI Upper-tropospheric winds derived from geostationary satellite water vapor observations SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID PREDICTION SYSTEM; RELATIVE-HUMIDITY; IMAGE DATA; MOTION; CLOUD; INTENSITY; CHANNEL; FIELDS AB The coverage and quality of remotely sensed upper-tropospheric moisture parameters have improved considerably with the deployment of a new generation of operational geostationary meteorological satellites: GOES-8/9 and GMS-5. The GOES-8/9 water vapor imaging capabilities have increased as a result of improved radiometric sensitivity and higher spatial resolution. The addition of a water vapor sensing channel on the latest GMS permits nearly global viewing of upper-tropospheric water vapor (when joined with GOES and Meteosat) and enhances the commonality of geostationary meteorological satellite observing capabilities. Upper-tropospheric motions derived from sequential water vapor imagery provided by these satellites can be objectively extracted by automated techniques. Wind fields can be deduced in both cloudy and cloud-free environments. In addition to the spatially coherent nature of these vector fields, the GOES-8/9 multispectral water vapor sensing capabilities allow for determination of wind fields over multiple tropospheric layers in cloud-free environments. This article provides an update on the latest efforts to extract water vapor motion displacements over meteorological scales ranging from subsynoptic to global. The potential applications of these data to impact operations, numerical assimilation and prediction, and research studies are discussed. C1 COOPERAT INST METEOROL SATELLITE STUDIES, MADISON, WI USA. NOAA, DATA & INFORMAT SERV, NATL ENVIRONM SATELLITE, MADISON, WI USA. NOAA, NESDIS, ADV SATELLITE PROD PROJECT, MADISON, WI USA. USN, RES LAB, MONTEREY, CA USA. RI Menzel, W. Paul/B-8306-2011 OI Menzel, W. Paul/0000-0001-5690-1201 NR 43 TC 172 Z9 179 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 1997 VL 78 IS 2 BP 173 EP 195 DI 10.1175/1520-0477(1997)078<0173:UTWDFG>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WQ051 UT WOS:A1997WQ05100001 ER PT J AU McAllister, MK Ianelli, JN AF McAllister, MK Ianelli, JN TI Bayesian stock assessment using catch-age data and the sampling - Importance resampling algorithm SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID POSTERIOR DISTRIBUTIONS; INFERENCE; PARAMETERS; FISHERY AB A Bayesian approach to fisheries stock assessment is desirable because it yields a probability density function (pdf) of population model parameters. This pdf can help to provide advice to fishery managers about the consequences of alternative harvest policies and convey uncertainty about quantities of interest such as population biomass. In stock assessment, catch-age data are commonly used to estimate population parameters. However, there are few catch-age analyses that use Bayesian methods. In this paper, we extend the sampling - importance resampling algorithm so that a pdf of population model parameters can be estimated using catch-age data and indices of relative abundance. We illustrate the procedure by estimating a 54-parameter pdf for yellowfin sole (Limanda aspera) in the eastern Bering Sea. The example demonstrates how catch-age data can markedly improve Bayesian estimation, and also illustrates the potential for significant biases in treating trawl survey abundance indices as absolute measures of stock size. C1 UNIV WASHINGTON,FISHERIES RES INST,SEATTLE,WA 98195. NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115. NR 48 TC 143 Z9 149 U1 2 U2 13 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD FEB PY 1997 VL 54 IS 2 BP 284 EP 300 DI 10.1139/cjfas-54-2-284 PG 17 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XB787 UT WOS:A1997XB78700006 ER PT J AU Au, DW Smith, SE AF Au, DW Smith, SE TI A demographic method with population density compensation for estimating productivity and yield per recruit of the leopard shark (Triakis semifasciata) SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID MUSTELUS-ANTARCTICUS GUNTHER; AUSTRALIAN WATERS; GUMMY SHARK; CALIFORNIA; GROWTH; MODEL AB A procedure is shown, using the leopard shark (Triakis semifasciata) as an example, for obtaining estimates of a population's intrinsic rate of increase (r) that depends on the level of total mortality borne. The method uses age at female maturity, maximum reproductive age, and average fecundity and incorporates concepts of density dependence from standard fisheries population modelling. An estimate of the leopard shark's r value at the population size producing maximum sustainable yield was thus obtained and then extended to adjust estimates of its yield per recruit for the effects of recruitment reduction under fishing pressure. The results indicate that this shark may be more susceptible to overexploitation than previously thought. This procedure is shown to be capable of returning r values for the leopard and five other species of sharks that compare favorably with published values obtained by the more standard life table method. It should prove useful for assessing the status of populations for which few data exist. RP Au, DW (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,POB 271,LA JOLLA,CA 92038, USA. NR 26 TC 37 Z9 37 U1 1 U2 7 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD FEB PY 1997 VL 54 IS 2 BP 415 EP 420 DI 10.1139/cjfas-54-2-415 PG 6 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XB787 UT WOS:A1997XB78700016 ER EF