FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Tans, PP AF Tans, PP TI The CO2 lifetime concept should be banished - Comment SO CLIMATIC CHANGE LA English DT Editorial Material ID CARBON-CYCLE RP Tans, PP (reprint author), NOAA,CLIMATE MONITORING & DIAGNOST LAB,325 BROADWAY,MAILCODE R-E-CG1,BOULDER,CO 80303, USA. NR 8 TC 3 Z9 3 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD NOV PY 1997 VL 37 IS 3 BP 487 EP 490 DI 10.1023/A:1005373006194 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA YE335 UT WOS:A1997YE33500003 ER PT J AU Smyth, KC Shaddix, CR Everest, DA AF Smyth, KC Shaddix, CR Everest, DA TI Aspects of soot dynamics as revealed by measurements of broadband fluorescence and flame luminosity in flickering diffusion flames SO COMBUSTION AND FLAME LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; LASER-INDUCED-FLUORESCENCE; QUANTITATIVE MEASUREMENTS; ANOMALOUS FLUORESCENCE; INDUCED INCANDESCENCE; EXCITED FLUORESCENCE; VISIBLE FLUORESCENCE; PREMIXED FLAMES; METHANE; LAMINAR AB Numerous investigators have attributed laser-induced broadband fluorescence observed in both rich, premixed flames and in diffusion flames to small polycyclic aromatic hydrocarbons (PAH). However, the wide variety of experimental flame conditions and excitation/detection wavelengths have clouded the interpretation of such measurements, for example, in terms of indicating either the presence of soot precursors or unreactive by-products (or both). This paper presents PAH fluorescence measurements excited at 283.5 nm and detected at 400-447 nm in a series of steady and flickering methane, propane, and ethylene diffusion flames burning at atmospheric pressure in an axisymmetric, coflow configuration. In the flickering flame experiments, acoustic forcing of the fuel rate is used to phase lock the periodic flame flicker close to the natural flame flicker frequency caused by buoyancy-induced instabilities. When compared to our earlier measurements of soot concentrations in the same flames, soot inception in the annular region is found to occur at the interface between the fluorescing PAH and the region of high radical concentrations. Although the peak PAH fluorescence signals and maximum soot concentrations do not occur at the same spatial locations, indirect evidence is presented that the species responsible for PAH fluorescence participate in either soot inception or growth. In contrast to prior suggestions that PAH fluorescence intensities scale with soot concentrations, the relative peak PAH fluorescence signals are observed to be 1.0:9.8:5.4 for the steady methane, propane, and ethylene flames, respectively, whereas the maximum soot levels follow a different trend of 1.0:19:39. Similar results are observed in the flickering flames, all of which exhibit enhanced PAH fluorescence signals compared to the steady flames. PAH fluorescence excited at 560.3 nm in the steady flames is also strongest for propane. Measurements of flame radiation arising from soot particles have also been made, with detection at 395-547 nm and to a limited degree at 833-900 nm. Visible flame emission is particularly sensitive to the local soot temperature. Comparison of the luminosity images with those of OH fluorescence and soot scattering shows that the luminosity is strongest where the hydroxyl radicals and soot layers overlap, i.e., in regions of active soot oxidation. (C) 1997 by The Combustion Institute. RP Smyth, KC (reprint author), NATL INST STAND & TECHNOL,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899, USA. NR 90 TC 71 Z9 71 U1 2 U2 16 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD NOV PY 1997 VL 111 IS 3 BP 185 EP 207 DI 10.1016/S0010-2180(97)00017-5 PG 27 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA XZ886 UT WOS:A1997XZ88600004 ER PT J AU Roubal, WT Lomax, DP Willis, ML Johnson, LL AF Roubal, WT Lomax, DP Willis, ML Johnson, LL TI Purification and partial characterization of English sole (Pleuronectes vetulus) vitellogenin SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY LA English DT Article DE vitellogenin; English sole; purification; characterization ID HALIBUT HIPPOGLOSSUS-HIPPOGLOSSUS; TROUT SALMO-GAIRDNERI; EEL ANGUILLA-JAPONICA; EGG-YOLK PROTEINS; SERUM-PROTEIN; INDUCTION; CHROMATOGRAPHY; AMERICANUS; CHEMICALS; COD AB Vitellogenin (VTG) was purified by double-step chromatography from plasma of male English sole treated with 17 beta-estradiol. The intact protein appeared to exist as a dimer in two forms of approximately 300 and 320 kDa and had an isoelectric point of 6.63. In SDS-PAGE, it was reduced to a single monomer of approximately 130 kDa. In immunoblotting, the protein showed cross-reactivity with coho salmon VTG antiserum. Native PAGE (sample not treated with the reducing agent mercaptoethanol) and immunoblotting of plasma from control and estradiol-treated male sole and gravid female sole demonstrated that the putative English sole VTG was normally female specific and estradiol inducible in males. It was immunocytochemically localized in liver and ovary of English sole, rock sole and starry flounder, using polyclonal antiserum to the purified protein from the estradiol treated male English sole. The protein was characterized as a phospholipoglycoprotein by native PAGE, staining the gels for phosphorus with methyl green, for lipid with Sudan black B and for carbohydrate by an improved periodic-acid Fuchsin sulfite method. The amino acid composition of the putative VTG was generally similar to that of VTGs from other teleosts, with the non-polar amino acids alanine, valine, leucine and isoleucine accounting for one-third of the total amino acids present. However, English sole vitellogenin contained a higher proportion of leucine and a lower proportion of glycine than most other teleost vitellogenins isolated to date. (C) 1997 Elsevier Science Inc. C1 Natl Marine Fisheries Serv, Environm Conservat Div, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Natl Marine Fisheries Serv, Environm Conservat Div, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 39 TC 37 Z9 51 U1 1 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1096-4959 EI 1879-1107 J9 COMP BIOCHEM PHYS B JI Comp. Biochem. Physiol. B-Biochem. Mol. Biol. PD NOV PY 1997 VL 118 IS 3 BP 613 EP 622 DI 10.1016/S0305-0491(97)00241-1 PG 10 WC Biochemistry & Molecular Biology; Zoology SC Biochemistry & Molecular Biology; Zoology GA YN975 UT WOS:000071228800019 PM 9467873 ER PT J AU Gockenbach, MS Kearsley, AJ Symes, WW AF Gockenbach, MS Kearsley, AJ Symes, WW TI An infeasible point method for minimizing the Lennard-Jones potential SO COMPUTATIONAL OPTIMIZATION AND APPLICATIONS LA English DT Article DE global optimization; penalty methods; non linear programming ID DIFFUSION EQUATION METHOD; MULTIPLE-MINIMA PROBLEM; OPTIMIZATION; CLUSTERS; VELOCITY; STATICS AB Minimizing the Lennard-Jones potential, the most-studied model problem for molecular conformation, is an unconstrained global optimization problem with a large number of local minima. In this paper, the problem is reformulated as an equality constrained nonlinear programming problem with only linear constraints. This formulation allows the solution to approached through infeasible configurations, increasing the basin of attraction of the global solution. In this way the likelihood of finding a global minimizer is increased. An algorithm for solving this nonlinear program is discussed, and results of numerical tests are presented. C1 NIST,APPL & COMPUTAT MATH DIV,GAITHERSBURG,MD 20899. RICE UNIV,DEPT COMPUTAT & APPL MATH,HOUSTON,TX 77251. RP Gockenbach, MS (reprint author), UNIV MICHIGAN,DEPT MATH,ANN ARBOR,MI 48109, USA. NR 24 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0926-6003 J9 COMPUT OPTIM APPL JI Comput. Optim. Appl. PD NOV PY 1997 VL 8 IS 3 BP 273 EP 286 DI 10.1023/A:1008627606581 PG 14 WC Operations Research & Management Science; Mathematics, Applied SC Operations Research & Management Science; Mathematics GA XX340 UT WOS:A1997XX34000004 ER PT J AU Golmie, N Masson, S Pieris, G Su, DH AF Golmie, N Masson, S Pieris, G Su, DH TI A MAC protocol for HFC networks: Design issues and performance evaluation SO COMPUTER COMMUNICATIONS LA English DT Article DE cable TV networks; HFC systems; MAC protocol; contention resolution algorithm AB Medium Access Control (MAC) layer protocols are designed to control transmissions over shared mediums. Bi-directional Cable Tv networks using Hybrid Fiber/Coazial (HFC) systems are good examples of broadcast environments where a MAC protocol is needed to allocate the multiaccess medium among the various nodes. One can think of a MAC protocol as a collection of components each performing a certain number of functions. An HFC MAC protocol can be broken into the following set of components: ranging or acquisition process, frame format, support for higher layer traffic classes, bandwidth allocation, bandwidth request, contention resolution mechanism. Ranging is the phase during which the round trip delay time to the head-end is calculated and the station synchronization to the downstream timing is performed. The frame format element of the MAC defines the upstream and downstream frames and describes their contents. If the MAC needs to provide support for ATM, it also needs to differentiate between different classes of traffic supported by ATM, such as Constant Bit Rate (CBR), Variable Bit Rate (VER) and Available Bit Rate (ABR). Bandwidth allocation represents an essential part of the MAC and controls the granting of requests at the headend. Finally, the contention resolution mechanism which is maybe the most important aspect of the MAC consists of a backoff phase and a retransmission phase. This paper examines two of the MAC elements mentioned above, namely the contention resolution and the bandwidth allocation mechanisms. Different solutions for each component are considered and evaluated. Performance is measured in terms of request delay, mean access delay and access delay probability distribution. Simulation results for configurations and scenarios of interest are also presented. Published by Elsevier Science B.V. C1 NIST, Gaithersburg, MD 20899 USA. RP Golmie, N (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 7 TC 7 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0140-3664 J9 COMPUT COMMUN JI Comput. Commun. PD NOV 1 PY 1997 VL 20 IS 12 BP 1042 EP 1050 DI 10.1016/S0140-3664(97)00090-X PG 9 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA YT667 UT WOS:000071630000002 ER PT J AU Marks, KM Stock, JM AF Marks, KM Stock, JM TI Early Tertiary gravity field reconstructions of the Southwest Pacific SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE Southwest Pacific; lower Tertiary; gravity anomalies; Geosat; plate tectonics; reconstruction ID PLATE MOTIONS; TASMAN SEA; RIDGE; AUSTRALIA; GEOPHYSICS; ANTARCTICA; EVOLUTION AB The aim of our study is to chronicle the development of plate boundaries in the Southwest Pacific Ocean during the early Tertiary. This region has been the subject of numerous and often conflicting studies that have attempted to construct the history of plate motion and plate boundary evolution as the Australia and Pacific plates separated from Antarctica. Our novel approach entails reconstructing gravity fields from satellite altimeter gravity by first removing anomalies overlying seafloor younger than a selected age, and then rotating the remaining anomalies through appropriate finite rotations. Our reconstructions reveal: (1) an extensional plate boundary (the Iselin rift) existed between West and East Antarctica prior to A24 time; (2) the arrival of the Southeast Indian ridge (SEIR) at the Tasman ridge (prior to A24) led to the extinction of the Iselin rift as well as the conversion of the easternmost portion of the Tasman plate boundary (between the SEIR and the Iselin rift) into a transform fault on the Pacific-Antarctic ridge; and (3) an early (A24 or younger) inception of the Australia-Pacific plate boundary, Our scenario for the opening of the Southwest Pacific Ocean can explain the present-day gravity anomalies and magnetic isochrons observed in the northwest Ross Sea. We find that the East Antarctic seafloor northeast of the Iselin Bank was generated by spreading on the Tasman ridge prior to A24 time. (C) 1997 Elsevier Science B.V. C1 NOAA, Lab Satellite Altimetry, Silver Spring, MD 20910 USA. CALTECH, Pasadena, CA 91125 USA. RP Marks, KM (reprint author), NOAA, Lab Satellite Altimetry, E-OC2, Silver Spring, MD 20910 USA. RI Marks, Karen/F-5610-2010; OI Marks, Karen/0000-0001-6524-1495; Stock, Joann Miriam/0000-0003-4816-7865 NR 24 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD NOV PY 1997 VL 152 IS 1-4 BP 267 EP 274 DI 10.1016/S0012-821X(97)00139-8 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA YN938 UT WOS:000071223900020 ER PT J AU Carlson, JK Parsons, GR AF Carlson, JK Parsons, GR TI Age and growth of the bonnethead shark, Sphyrna tiburo, from northwest Florida, with comments on clinal variation SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE life history; elasmobranchs; ageing; cline; early growth ID ATLANTIC SHARPNOSE SHARK; RHIZOPRIONODON-TERRAENOVAE; 2 POPULATIONS AB Age and growth rates of the bonnethead shark, Sphyrna tiburo, from northwest Florida were estimated from vertebrae collected between October 1992 and October 1995. The von Bertalanffy growth equation was fit to male and female vertebral age data. Initial growth was rapid (approximate to 200 mm TL) for both sexes from age 0-1. At age 2 growth slowed for males but continued for females. Similar to many species of sharks, females grew slower than males (K = 0.28 and K = 0.69, respectively) but attained a larger maximum size (L-infinity = 1226 and L-infinity = 897). Maximum age was estimated in males and females to be 8+ and 12+ years, respectively. Growth of young-of-year sharks was 21 to 30 mm TL per month determined by three different methods. A comparison of age and growth estimates from populations at more southerly latitudes suggest that clinal variation in total length may be evident among bonnethead sharks in the Gulf of Mexico with females reaching larger sizes in northern areas as compared to south Florida. C1 UNIV MISSISSIPPI,DEPT BIOL,UNIVERSITY,MS 38677. RP Carlson, JK (reprint author), NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,3500 DELWOOD BEACH RD,PANAMA CITY,FL 32408, USA. NR 21 TC 33 Z9 35 U1 0 U2 8 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 NOV PY 1997 VL 50 IS 3 BP 331 EP 341 DI 10.1023/A:1007342203214 PG 11 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA YD417 UT WOS:A1997YD41700009 ER PT J AU MacDonald, LH Anderson, DM Dietrich, WE AF MacDonald, LH Anderson, DM Dietrich, WE TI Paradise threatened: Land use and erosion on St. John, US Virgin Islands SO ENVIRONMENTAL MANAGEMENT LA English DT Article DE erosion; sediment yield; roads; dry tropics; development ID SEDIMENT; FOREST AB Rapid development and the concomitant increases in erosion and sedimentation are believed to threaten the reefs and other marine resources that are a primary attraction of St. John and Virgin Islands National Park. Average annual sediment yields from undeveloped areas were estimated from a sediment pond and a mangrove swamp as less than 20 and less than 40 t/km(2)/yr, respectively. Geomorphic evidence indicates that plantation agriculture during the 18th and 19th centuries did not cause severe Erosion. Since about 1950 there has been rapid growth in roads and development due to increasing tourism and second-home development. Cur field investigations identified the approximately 50 km of unpaved roads as the primary source of anthropogenic sediment. Field measurements of the road network in two catchments led to the development of a vector-based GIS model to predict road surface erosion and sediment delivery. We estimate that road erosion has caused at least a fourfold increase in island-wide sediment yields and that current sedimentation rates are unprecedented. Paving the dirt roads and implementing standard sediment control practices can greatly reduce current sediment yields and possible adverse effects on the marine ecosystems surrounding St. John. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720. RP MacDonald, LH (reprint author), COLORADO STATE UNIV,DEPT EARTH RESOURCES,FT COLLINS,CO 80523, USA. NR 41 TC 49 Z9 51 U1 1 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0364-152X J9 ENVIRON MANAGE JI Environ. Manage. PD NOV-DEC PY 1997 VL 21 IS 6 BP 851 EP 863 DI 10.1007/s002679900072 PG 13 WC Environmental Sciences SC Environmental Sciences & Ecology GA XX882 UT WOS:A1997XX88200012 ER PT J AU Yang, JC Chien, W King, M Grosshandler, WL AF Yang, JC Chien, W King, M Grosshandler, WL TI A simple piezoelectric droplet generator SO EXPERIMENTS IN FLUIDS LA English DT Article ID COLLISION AB A design for a piezoelectric on-demand droplet generator is presented. Its simple construction and ease of operation distinguish this generator from others previously reported. The droplet generator has been successfully used to produce droplets of aqueous solutions with very high dissolved salt loadings and is currently used to study droplet import and evaporation on a heated surface. RP Yang, JC (reprint author), NIST,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899, USA. NR 8 TC 23 Z9 24 U1 0 U2 13 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD NOV PY 1997 VL 23 IS 5 BP 445 EP 447 DI 10.1007/s003480050134 PG 3 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA YK847 UT WOS:A1997YK84700013 ER PT J AU Kopp, M Doucette, GJ Kodama, M Gerdts, G Schutt, C Medlin, LK AF Kopp, M Doucette, GJ Kodama, M Gerdts, G Schutt, C Medlin, LK TI Phylogenetic analysis of selected toxic and non-toxic bacterial strains isolated from the toxic dinoflagellate Alexandrium tamarense SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article DE bacteria; dinoflagellate; phycotoxin; paralytic shellfish poison; rRNA AB Recent evidence has implicated bacterial involvement in the production of paralytic shellfish poison toxins, which are normally associated with bloom-forming algal species, specifically toxic dinoflagellate algae. Preliminary reports of the identification of toxin-producing bacteria isolated from the toxic marine dinoflagellate Alexandrium tamarense suggested that they belonged to the gamma sub-division of the Proteobacteria, specifically related to the bacterium Moraxella. Digoxigenin-labelled alpha, beta and gamma ribosomal rRNA probes, hybridized to both toxigenic and non-toxigenic bacteria isolated from several strains of Alexandrium tamarense, indicated that the bacteria belonged to the alpha sub-division of the Proteobacteria. Phylogenetic analysis of small subunit ribosomal RNA coding regions confirmed this and provided strong evidence that these bacteria are likely to represent a new genus in that group. C1 ALFRED WEGENER INST POLAR & MARINE RES,D-27570 BREMERHAVEN,GERMANY. NATL MARINE FISHERIES SERV,CHARLESTON LAB,MARINE BIOTOXINS PROGRAM,CHARLESTON,SC 29412. KITASATO UNIV,SCH FISHERIES SCI,LAB MARINE BIOL CHEM,SANRIKU,IWATE 02201,JAPAN. BIOL ANSTALT HELGOLAND,D-27498 HELGOLAND,GERMANY. RI medlin, linda/G-4820-2010; Doucette, Gregory/M-3283-2013 NR 33 TC 21 Z9 25 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD NOV PY 1997 VL 24 IS 3 BP 251 EP 257 DI 10.1016/S0168-6496(97)00066-4 PG 7 WC Microbiology SC Microbiology GA YE981 UT WOS:A1997YE98100007 ER PT J AU Rhoderick, GC AF Rhoderick, GC TI Development of a fifteen component hydrocarbon gas standard reference material at 5 nmol/mol in nitrogen SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article ID ORGANIC-COMPOUNDS AB Primary gravimetric gas cylinder standards containing fifteen alkane, alkene and aromatic hydrocarbons (C-2-C-10) were prepared. A procedure previously developed to prepare gas cylinder standards for volatile organic compounds at the 5 nmol/mol (ppb) level was used. The set of primary hydrocarbon gas standards prepared by this procedure were intercompared by using gas chromatography with a hydrogen flame ionization detector (GC-FID). The linear regression analysis showed excellent agreement among the standards for each compound. Similar mixtures containing many of these hydrocarbons have been evaluated over time and have shown stability of the concentrations in aluminum gas cylinders for three years. This research resulted in the production and certification of Standard Reference Material (SRM) 1800, which contains fifteen hydrocarbons in nitrogen at a nominal concentration of 5 nmol/mol for each analyte. A batch of twenty-four cylinders containing the mixture was prepared at NIST following previously demonstrated protocols for their preparation. Each cylinder was analyzed against one cylinder from the batch, designated as the ''lot control'', for each of the fifteen hydrocarbons. The data showed that the batch was homogeneous, from 0.2 to 0.7% depending on the compound, and stable for each hydrocarbon in the mixture resulting in certification and issuance of SRM 1800. RP Rhoderick, GC (reprint author), NIST,CHEM SCI & TECHNOL LAB,ORGAN ANALYT RES DIV,GAS METROL RES CTR,GAITHERSBURG,MD 20899, USA. NR 10 TC 13 Z9 14 U1 2 U2 4 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 NOV PY 1997 VL 359 IS 6 BP 477 EP 483 DI 10.1007/s002160050617 PG 7 WC Chemistry, Analytical SC Chemistry GA YJ059 UT WOS:A1997YJ05900003 ER PT J AU Peng, YG Clayton, EC Means, LW Ramsdell, JS AF Peng, YG Clayton, EC Means, LW Ramsdell, JS TI Repeated independent exposures to domoic acid do not enhance symptomatic toxicity in outbred or seizure-sensitive inbred mice SO FUNDAMENTAL AND APPLIED TOXICOLOGY LA English DT Article ID KAINIC ACID; BRAIN; RAT; NEUROTOXICITY; MECHANISMS; MUSSELS; POISON; TOXIN AB Domoic acid (DA) is an environmental neurotoxin to humans. This work examines whether repeated exposure to subsymptomatic or symptomatic nonlethal doses of domoic acid leads to enhanced symptomatic toxicity in ICR outbred and DBA inbred strains of laboratory mice. A multiple independent exposure paradigm was designed in which doses were administered intraperitoneally every other day for 7 days to achieve four separate exposures to domoic acid. We first examined the effect of repeated exposure on serum clearance of domoic acid. Serum domoic acid levels did not differ following a single or repeated exposure. We next examined the effect of repeated exposure on symptomatic toxicity. The mean toxicity scores did not show a significant difference between single and repeated exposures of either subsymptomatic (0.5 mg/kg) or symptomatic sublethal (2.0 mg/kg) doses of domoic acid. We then examined the effects of repeated domoic acid exposure on a second strain of mouse. DBA mice were chosen based upon their sensitivity to kainic acid-induced seizures; however, the ICR mice were more sensitive to low-dose domoic acid toxicity, particularly in terms of onset and duration of stereotypic scratching behavior. Our results indicate that both strains of mice have comparable concentration-dependent toxic responses to domoic acid; however, differences exist in the magnitude of the response and in specific symptoms. The mean toxicity scores did not show a significant difference when a single exposure (1.0 and 2.0 mg/kg domoic acid) and repeated exposure of the same dose were compared in the DBA mice. This study provides no evidence that short-term repeated exposure to domoic acid in laboratory mice alters domoic acid clearance from the serum, or leads to a more sensitive or a greater neurotoxic response. (C) 1997 Society of Toxicology. C1 E CAROLINA UNIV,DEPT PSYCHOL,GREENVILLE,NC 27858. RP Peng, YG (reprint author), MED UNIV S CAROLINA,MARINE BIOTOXINS PROGRAM,NOAA,SE FISHERIES SCI CTR,CHARLESTON LAB,CHARLESTON,SC 29412, USA. NR 23 TC 19 Z9 21 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0272-0590 J9 FUND APPL TOXICOL JI Fundam. Appl. Toxicol. PD NOV PY 1997 VL 40 IS 1 BP 63 EP 67 DI 10.1006/faat.1997.2360 PG 5 WC Toxicology SC Toxicology GA YK776 UT WOS:A1997YK77600006 PM 9398488 ER PT J AU Mananos, EL Swanson, P Stubblefield, S Zohar, Y AF Mananos, EL Swanson, P Stubblefield, S Zohar, Y TI Purification of gonadotropin II from a teleost fish, the hybrid striped bass, and development of a specific enzyme-linked immunosorbent assay SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article ID DISTINCT SALMON GONADOTROPINS; RAINBOW-TROUT; GTH-II; ONCORHYNCHUS-MYKISS; MOLECULAR-CLONING; PITUITARY-GLANDS; HOMOLOGOUS RADIOIMMUNOASSAY; GILTHEAD SEABREAM; SEQUENCE-ANALYSIS; SPARUS-AURATA AB A highly purified gonadotropin II (GtH II), referred to as striped bass GtH II (stbGtH II), and its alpha and beta subunits were prepared from pituitaries of sexually mature hybrid striped bass. Pituitary glycoproteins were extracted with ethanol and intact stbGtH II purified by gel-filtration chromatography on Sephadex G-100, ion-exchange chromatography (IEC) on DE-52, and fast-performance liquid chromatography (FPLC) on Superdex 75. The presence of GtHs during the purification procedure was monitored by characteristic elution on reversed-phase highperformance liquid chromatography (rpHPLC) and in vitro steroidogenic activity. The stbGtH II alpha and beta subunits were purified from the pituitary ethanol extract by gel-filtration, IEC, and rpHPLC, and their identities assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), rpHPLC, and N-terminal amino acid sequencing. Molecular weights of intact stbGtH II and its alpha and beta subunits, determined by SDS-PAGE, were 34.5, 14.8, and 20.4 kDa, respectively. The stbGtH II beta subunit was used to produce specific antibodies, and a competitive enzyme-linked immunosorbent assay was developed using intact stbGtH II for the standard curve. The sensitivity of the assay was 156 pg/ml (15.6 pg/well) and the intra-and interassay coefficients of variation (at 50% binding) were 7.7% (n = 16) and 8.7% (n = 10), respectively. Physiological validation of the assay was performed by measuring changes of plasma GtH II levels in mature striped bass females, after injection of GnRHa ([D-Ala(6),Pro(9)-NEt]-mGnRH, 100 mu g/kg BW). A maximum surge of GtH II in plasma was observed at 12 hr postinjection (22.5 +/- 3.01 ng/ml), whereas GtH II levels in control fish (around 4 ng/ml) remained unchanged. Displacement curves obtained with serial dilutions of plasma and pituitaries from a number of perciform species were parallel to the standard curve, indicating that this assay can be used for GtH II measurements in a variety of fish species. (C) 1997 Academic Press. C1 UNIV MARYLAND,CTR MARINE BIOTECHNOL,COLUMBUS CTR,INST BIOTECHNOL,BALTIMORE,MD 21202. NW FISHERIES SCI CTR,SEATTLE,WA 98112. RI Mananos, Evaristo/B-9708-2015 OI Mananos, Evaristo/0000-0001-5811-3882 FU PHS HHS [93-37203-9409] NR 45 TC 56 Z9 58 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 0016-6480 J9 GEN COMP ENDOCR JI Gen. Comp. Endocrinol. PD NOV PY 1997 VL 108 IS 2 BP 209 EP 222 DI 10.1006/gcen.1997.6966 PG 14 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA YF505 UT WOS:A1997YF50500005 PM 9356217 ER PT J AU Walker, RJ Morgan, JW Beary, ES Smoliar, MI Czamanske, GK Horan, MF AF Walker, RJ Morgan, JW Beary, ES Smoliar, MI Czamanske, GK Horan, MF TI Applications of the Pt-190-Os-186 isotope system to geochemistry and cosmochemistry SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID PLATINUM-GROUP ELEMENTS; IRON-METEORITES; MANTLE-PLUME; OCEANIC BASALTS; ISLAND BASALTS; SIBERIAN TRAP; FLOOD BASALTS; SULFIDE ORES; ND-ISOTOPE; OSMIUM AB Platinum is fractionated from osmium primarily as a consequence of processes involving sulfide and metal crystallization. Consequently, the Pt-190-Os-186 isotope system (Pt-190-->Os-186 + alpha) shows promise for dating some types of magmatic sulfide ores and evolved iron meteorites. The first Pt-190-Os-186 isochrons are presented here for ores from the ca. 251 Ma Noril'sk, Siberia plume, and for group IIAB magmatic iron meteorites. Given the known age of the Noril'sk system, a decay constant for Pt-190 is determined to be 1.542 x 10(-12)a(-1), with +/-1% uncertainty. The isochron generated for the IIAB irons is consistent with this decay constant and the known age of the group. The Os-186/Os-188 ratios of presumably young, mantle-derived osmiridiums and also the carbonaceous chondrite Allende were measured to high-precision to constrain the composition of the modern upper mantle. These compositions overlap, indicating that the upper mantle is chondritic within the level of resolution now available. Our best estimate for this Os-186/Os-188 ratio is 0.119834 +/- 2 (2 sigma(M)). The Pt-190/Os-186 ratios determined for six enstatite chondrites average 0.001659 +/- 75, which is very similar to published values for carbonaceous chondrites. Using this ratio and the presumed composition of the modern upper mantle and chondrites, a solar system initial Os-186/Os-188 ratio of 0.119820 is calculated. In comparison to the modern upper mantle composition, the Os-186/Os-188 ratio of the Noril'sk plume was approximately 0.012% enriched in Os-186. Possible reasons for this heterogeneity include the recycling of Pt-rich crust into the mantle source of the plume and derivation of the osmium from the outer core. Derivation of the osmium from the outer core is our favored model. Copyright (C) 1997 Elsevier Science Ltd. C1 Univ Maryland, Dept Geol, Isotope Geochem Lab, College Pk, MD 20742 USA. Colorado State Univ, Dept Earth Resources, Ft Collins, CO 80523 USA. NIST, Gaithersburg, MD 20899 USA. US Geol Survey, Menlo Park, CA 94025 USA. RP Walker, RJ (reprint author), Carnegie Inst Washington, Dept Terr Magnetism, 5241 Broad Branch Rd NW, Washington, DC 20015 USA. RI Walker, Richard/K-6869-2016 OI Walker, Richard/0000-0003-0348-2407 NR 51 TC 132 Z9 144 U1 0 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD NOV PY 1997 VL 61 IS 22 BP 4799 EP 4807 DI 10.1016/S0016-7037(97)00270-6 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA YM712 UT WOS:000071093300007 ER PT J AU Chereskin, TK Wilson, WD Bryden, HL Ffield, A Morrison, J AF Chereskin, TK Wilson, WD Bryden, HL Ffield, A Morrison, J TI Observations of the Ekman balance at 8 degrees 30' N in the Arabian Sea during the 1995 southwest monsoon SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN; TRANSPORTS; CURRENTS AB The Ekman transport is estimated from two sets of hydrographic and shipboard acoustic Doppler current profiler (ADCP) velocity observations made during June and September 1995, during the southwest monsoon in the Arabian Sea. Both sets of measurements were made along latitude 8 degrees 30' N, designated as World Ocean Circulation Experiment (WOCE) line I1W, from Somalia to Sri Lanka. The Ekman transport estimates calculated from ageostrophic velocity were southward: 17.6 +/- 2.4 10(6) m(3) s(-1) in June and 7.9 +/- 2.7 10(6) m(3) s(-1) in September. These direct estimates were in good agreement with those predicted by the Ekman balance using both shipboard and climatological winds. The vertical structure of the ageostrophic velocity and the stratification were quite different between the two occupations of the transect. The wind-driven momentum was confined to a very shallow layer in June (about 50 m) and the surface layer was strongly stratified, with a maximum salinity layer at depths between 50 and 70 m. The ageostrophic velocity penetrated much deeper in September (to about 160 m) and the pycnocline was correspondingly deeper. In both cases, the Ekman transport penetrated beneath the mixed layer, to the top of the pycnocline. C1 NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33124. SOUTHAMPTON OCEANOG CTR,SOUTHAMPTON SO14 3ZH,HANTS,ENGLAND. LAMONT DOHERTY EARTH OBSERV,PALISADES,NY 10964. N CAROLINA STATE UNIV,RALEIGH,NC 27695. RP Chereskin, TK (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093, USA. NR 10 TC 20 Z9 21 U1 1 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 NOV 1 PY 1997 VL 24 IS 21 BP 2541 EP 2544 DI 10.1029/97GL01057 PG 4 WC Geosciences, Multidisciplinary SC Geology GA YE985 UT WOS:A1997YE98500002 ER PT J AU Gordon, AL Ma, SB Olson, DB Hacker, P Ffield, A Talley, LD Wilson, D Baringer, M AF Gordon, AL Ma, SB Olson, DB Hacker, P Ffield, A Talley, LD Wilson, D Baringer, M TI Advection and diffusion of Indonesian throughflow water within the Indian Ocean South Equatorial Current SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GEOSTROPHIC TRANSPORT; THERMOCLINE; PACIFIC; SEAS; CIRCULATION; AREA AB Warm, low salinity Pacific water weaves through the Indonesian Seas into the eastern boundary of the Indian Ocean. The Indonesian Throughflow Water (ITW) adds freshwater into the Indian Ocean as it spreads by the advection and diffusion within the Indian Ocean's South Equatorial Current (SEC). The low salinity throughflow trace, centered along 12 degrees S, stretches across the Indian Ocean, separating the monsoon dominated regime of the northern Indian Ocean from the more typical subtropical stratification to the south. ITW is well represented within the SEC thermocline, extending with concentrations above 80% of initial characteristics from the sea surface to 300-m within the eastern half of the Indian Ocean, with 60% concentration reaching well into the western Indian Ocean. The ITW transport within the SEC varies from 4 to 12 x 10(6) m(3)sec(-1), partly in response to variations of the injection rate at the eastern boundary and to the likelihood of a zonally elongated recirculation cell between the Equatorial Counter Current and the SEC within the Indian Ocean. Lateral mixing disperses the ITW plume meridionally with an effective isopycnal mixing coefficient of 1.1 to 1.6 x 10(4) m(2)sec(-1). C1 UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MIAMI,FL 33149. UNIV HAWAII,SCH OCEAN & EARTH SCI & TECHNOL,HONOLULU,HI 96822. UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093. NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33149. RP Gordon, AL (reprint author), COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964, USA. RI Gordon, Arnold/H-1049-2011; Baringer, Molly/D-2277-2012; OI Gordon, Arnold/0000-0001-6480-6095; Baringer, Molly/0000-0002-8503-5194; Olson, Donald/0000-0001-7180-5672 NR 24 TC 51 Z9 53 U1 0 U2 5 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 NOV 1 PY 1997 VL 24 IS 21 BP 2573 EP 2576 DI 10.1029/97GL01061 PG 4 WC Geosciences, Multidisciplinary SC Geology GA YE985 UT WOS:A1997YE98500010 ER PT J AU Donaldson, DJ Frost, GJ Rosenlof, KH Tuck, AF Vaida, V AF Donaldson, DJ Frost, GJ Rosenlof, KH Tuck, AF Vaida, V TI Atmospheric radical production by excitation of vibrational overtones via absorption of visible light SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NITRIC-ACID; UNIMOLECULAR REACTIONS; PHOTOLYSIS; DYNAMICS; PHOTODISSOCIATION; RADIATION; HYDROGEN; TWILIGHT; O-3 AB We present calculations using a radiative transfer model which predict that in the lower stratosphere at high zenith angles, significant enhancements to the photodissociation rates of HNO3 and HNO4 can result from visible wavelength excitation of OH overtone vibrations containing sufficient energy to cleave the O-O and N-O bonds. The results indicate that atmospheric chromophores such as HONO2. HO2NO2 and H2O2, could make a potentially significant contribution to the production of HOx and NOx. Calculating the relative importance of their effect requires better knowledge of the absolute absorption cross sections: both for vibrational overtones and in the near UV. Stratospheric air masses in which this process could be important are those that experience lengthy exposure at high solar zenith angles: the outer regions of the polar winter vortex and the polar summer anticyclone. We note that the general mechanism may have application elsewhere such as in the atmospheres of other planets and in generating the diffuse interstellar bands associated with molecular clouds. C1 NOAA,AERON LAB,BOULDER,CO 80303. UNIV COLORADO,DEPT CHEM,BOULDER,CO 80309. UNIV TORONTO,SCARBOROUGH COLL,TORONTO,ON M5S 1A1,CANADA. RP Donaldson, DJ (reprint author), UNIV TORONTO,DEPT CHEM,80 ST GEORGE ST,TORONTO,ON M5S 1A1,CANADA. RI Tuck, Adrian/F-6024-2011; Frost, Gregory/I-1958-2013; Vaida, Veronica/N-6069-2014; Rosenlof, Karen/B-5652-2008; Donaldson, James/G-7120-2012 OI Tuck, Adrian/0000-0002-2074-0538; Vaida, Veronica/0000-0001-5863-8056; Rosenlof, Karen/0000-0002-0903-8270; Donaldson, James/0000-0002-5090-3318 NR 26 TC 84 Z9 84 U1 0 U2 10 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 NOV 1 PY 1997 VL 24 IS 21 BP 2651 EP 2654 DI 10.1029/97GL02663 PG 4 WC Geosciences, Multidisciplinary SC Geology GA YE985 UT WOS:A1997YE98500031 ER PT J AU Kawalko, SF Kanda, M AF Kawalko, SF Kanda, M TI Effective length and input impedance of the NIST standard dipoles SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE antenna input impedance; effective length; standard antenna method; standard dipole AB Computed values for the effective length and input impedance for a set of standard dipoles used at the National Institute of Standards and Technology will be presented, These dipoles are used as calculable reference antennas iaa the calibration of dipole-like electromagnetic interference antennas in an open-area test site, Estimates for the uncertainty in the computed values of the effective length and antenna impedance will also be given. RP Kawalko, SF (reprint author), NATL INST STAND & TECHNOL, DIV ELECTROMAGNET FIELDS, BOULDER, CO 80303 USA. NR 4 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 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD NOV PY 1997 VL 39 IS 4 BP 404 EP 408 DI 10.1109/15.649849 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA YG016 UT WOS:A1997YG01600021 ER PT J AU Kawalko, SF Kanda, M AF Kawalko, SF Kanda, M TI Near-zone gain of open-ended rectangular waveguides SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE anechoic chamber; near-zone gain; open-ended waveguides ID SURFACES AB Full-wave solutions ta the problem of radiation by open-ended rectangular waveguides (OEG) are presented. The radiation problem is formulated in terms of an electric field integral equation (EFIE). The EFIE is solved using the method of moments for three OEG antennas covering the frequncy range from 200 to 750 MHz. Results For the near-zone gains as a function of both frequency and distance from the OEG aperture are presented, Estimates for uncertainties in the calculated gain are also given. RP Kawalko, SF (reprint author), NATL INST STAND & TECHNOL,DIV ELECTROMAGNET FIELDS,BOULDER,CO 80303, USA. NR 10 TC 4 Z9 4 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 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD NOV PY 1997 VL 39 IS 4 BP 408 EP 413 DI 10.1109/15.649850 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA YG016 UT WOS:A1997YG01600022 ER PT J AU Parker, TE Levine, J AF Parker, TE Levine, J TI Impact of new high stability frequency standards on the performance of the NIST AT1 time scale SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article AB The recent addition of new commercial high stability frequency standards to the National Institute of Standards and Technology (NIST) real time AT1 time scale has resulted in significant improvements in the performance of the scale. The frequency stability of the scale at one day has increased by a factor of 2 to 4 x 10(-15) and the stability at 100 days has improved to approximately 1 x 10(-15), As a result UTC (NIST) has been kept within 50 ns of UTC (Coordinated Universal Time) for the last year, Further improvements are anticipated as more high performance clocks are added to the AT1 ensemble. RP Parker, TE (reprint author), NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,BOULDER,CO 80303, USA. NR 9 TC 10 Z9 11 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD NOV PY 1997 VL 44 IS 6 BP 1239 EP 1244 DI 10.1109/58.656627 PG 6 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA YH557 UT WOS:A1997YH55700010 ER PT J AU Zelkowitz, MV Wallace, D AF Zelkowitz, MV Wallace, D TI Experimental validation in software engineering SO INFORMATION AND SOFTWARE TECHNOLOGY LA English DT Article; Proceedings Paper CT Conference on Evaluation and Assessment in Software Engineering (EASE 97) CY MAR, 1997 CL KEELE UNIV, KEELE, ENGLAND HO KEELE UNIV DE data collection; experimentation; evaluation; measurement ID IMPROVEMENT AB Although experimentation is an accepted approach toward scientific validation in most scientific disciplines, it only recently has gained acceptance within the software development community. In this paper we discuss a 12-model classification scheme for performing experimentation within the software development domain. We evaluate over 600 published papers in the computer science literature and over one hundred papers from other scientific disciplines in order to determine: (1) how well the computer science community is succeeding at validating its theories, and (2) how computer science compares to other scientific disciplines. Published by Elsevier Science B.V. C1 NIST, ITL, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Comp Sci, College Pk, MD 20742 USA. RP Zelkowitz, MV (reprint author), NIST, ITL, Gaithersburg, MD 20899 USA. NR 10 TC 56 Z9 56 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0950-5849 J9 INFORM SOFTWARE TECH JI Inf. Softw. Technol. PD NOV PY 1997 VL 39 IS 11 BP 735 EP 743 DI 10.1016/S0950-5849(97)00025-6 PG 9 WC Computer Science, Information Systems; Computer Science, Software Engineering SC Computer Science GA YM120 UT WOS:000071030700002 ER PT J AU de Gouw, JA Krishnamurthy, M Bierbaum, VM Leone, SR AF de Gouw, JA Krishnamurthy, M Bierbaum, VM Leone, SR TI Measured and calculated mobilities of cluster ions drifting in helium and in nitrogen SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE ion; mobility; cluster; drift tube ID INFORMATION; REACTIVITY; RANGE; ATOMS AB New experimental results are presented for the mobilities of (1) the H3O+(H2O)(3) cluster ion drifting in He (the reduced zero-field mobility K-0((0)) is 11.5 +/- 0.4 cm(2) V-1 s(-1), (2) NO+(CH3COCH3)(n) cluster ions drifting in He (K-0((0)) = 7.5 +/- 0.4 cm(2) V-1 s(-1) for n = 2, K-0((0)) = 7.3 +/- 0.5 cm(2) V-1 s(-1) for n 3), and (3) the NO+(CH3CN)(2) cluster ion drifting in N-2 (K-0((0))) = 1.70 +/- 0.06 cm(3) V-1 s(-1)). These results together with other recently reported cluster ion mobilities in He are quantitatively explained using the hard-sphere collision model by von Helden et al. (J. Phys. Chem. 97 (1993) 8182-8192). The role of ion-induced dipole interactions is investigated and shown to be minor for the mobilities of all but the smallest ions in He. The existing data on cluster-ion mobilities in N-2. including the result here, are systematized. As a result of the stronger polarizability of N-2, the hard-sphere collision model does not agree with the data, and a better explanation is obtained using a simple model that includes ion-induced dipole interactions. The size of the cluster has only a minor effect on the mobility in N-2. The remaining discrepancies between the measured and calculated results are attributed to ion-quadrupole or dipole induced-dipole interactions. (C) 1997 Elsevier Science B.V. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Leone, SR (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI de Gouw, Joost/A-9675-2008 OI de Gouw, Joost/0000-0002-0385-1826 NR 23 TC 18 Z9 18 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD NOV PY 1997 VL 167 BP 281 EP 289 DI 10.1016/S0168-1176(97)00075-X PG 9 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA ZB778 UT WOS:000072507100026 ER PT J AU Outcalt, SL McLinden, MO AF Outcalt, SL McLinden, MO TI An equation of state for the thermodynamic properties of R143a (1,1,1-trifluoroethane) SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE 1,1,1-trifluoroethane (R143a); equation of state; refrigerants; thermodynamic properties ID THERMO-PHYSICAL PROPERTIES; GAS-PHASE; 2,2-DICHLORO-1,1,1-TRIFLUOROETHANE; METHANE AB Thermodynamic properties of 1,1,1-trifluoroethane (R143a) are expressed in terms of a 32-term modified Benedict-Webb-Rubin (MBWR) equation of state. Coefficients are reported for the MBWR equation and for ancillary equations used to fit the ideal-gas heat capacity, and the coexisting densities and pressure along the saturation boundary. The MBWR coefficients were determined from a multiproperty fit that used the following types of experimental data: PVT; isochoric, isobaric, and saturated-liquid heat capacities; second virial coefficients; speed of sound and properties at coexistence. The equation of state was optimized to the experimental data from 162 to 346 K and pressures to 35 MPa with the exception of the critical region. Upon extrapolation to 500 K and 60 MPa, the equation gives thermodynamically reasonable results. Comparisons between calculated and experimental values are presented. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Outcalt, SL (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 28 TC 18 Z9 18 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD NOV PY 1997 VL 18 IS 6 BP 1445 EP 1463 DI 10.1007/BF02575344 PG 19 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA YL803 UT WOS:000070994400007 ER PT J AU Matsumoto, T Cezairliyan, A AF Matsumoto, T Cezairliyan, A TI A combined transient and brief steady-state technique for measuring hemispherical total emissivity of electrical conductors at high temperatures: Application to tantalum SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE emissivity; hemispherical total emissivity; high temperatures; normal spectral emissivity; pulse heating; tantalum ID MOLYBDENUM AB A new method for measuring hemispherical total emissivity of electrically conducting materials at high temperatures (above 1500 K) using a feedback-controlled pulse-heating technique has been developed. The technique is based on rapid resistive self-heating of a solid cylindrical specimen in vacuum up to a preset high temperature in a short time (about 200 ms) and then keeping the specimen at that temperature under steady state conditions for a brief period (about 500 ms) before switching off the current through the specimen. The specimen is maintained at constant temperature with a feedback control system which controls the current through the specimen. The computer-controlled feedback system operates a solid-state switch (composed of field-effect transistors). The sensing signal for the feedback is provided by a high-speed optical pyrometer. Hemispherical total emissivity is determined at the temperature plateau from the data on current through the specimen, the voltage drop across the middle portion of the specimen, and the specimen temperature using the steady-state heat balance equation based on the Stefan-Boltzmann law. The true temperature of the specimen is determined from the measured radiance temperature and the normal spectral emissivity; the latter is obtained from laser polarimetric measurements. The experimental quantities are measured and recorded every 0.2 ms with a 12-bit digital oscilloscope. To demonstrate the feasibility of the technique, experiments were conducted on a tantalum specimen in the temperature range 2000 to 2800 K. The results on hemispherical total emissivity are presented and are compared with the data given in the literature. C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. Natl Res Lab Metrol, Measurement Syst Dept, Tsukuba, Ibaraki 305, Japan. RP Cezairliyan, A (reprint author), Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. NR 19 TC 21 Z9 21 U1 1 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD NOV PY 1997 VL 18 IS 6 BP 1539 EP 1556 DI 10.1007/BF02575350 PG 18 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA YL803 UT WOS:000070994400013 ER PT J AU Smith, DR AF Smith, DR TI Thermal conductivity of fibrous glass board by guarded hot plates and heat flow meters: An international round-robin SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE fibrous glass; guarded hot plate; heat flow meter; thermal conductivity; thermal insulation AB In the early 1980s, an international round-robin was held in which the apparent thermal conductivity of specimens of fibrous glass insulation board was measured by users of guarded hot plates (GHPs) and heat-flow meters (HFMs). The round-robin was performed over a period of several years by laboratories in Europe, North America, Australia, and the Far East. Participants in this round-robin were organized into 12 "loops," 8 for participants with GHPs and 4 for those with HFMs. Each loop included laboratories located in the same region of the world and sharing the same set of specimens. In an attempt to obtain insight into the accuracy of the measurements, participants were also asked to measure the thermal conductivity of a layer of air. The data submitted in this round-robin are exhibited and analyzed. The overall agreement of individual measurements with a least-squares fitted curve, as measured by one standard deviation sigma, was sigma = 2.4% for GHPs and sigma = 2.7% for HFMs. Suggestions are made for conducting future round-robins of this type. C1 Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA. RP Smith, DR (reprint author), Natl Inst Stand & Technol, Div Mat Reliabil, 325 Broadway, Boulder, CO 80303 USA. NR 2 TC 6 Z9 6 U1 0 U2 3 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD NOV PY 1997 VL 18 IS 6 BP 1557 EP 1573 DI 10.1007/BF02575351 PG 17 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA YL803 UT WOS:000070994400014 ER PT J AU Reinking, RF Matrosov, SY Martner, BE Kropfli, RA AF Reinking, RF Matrosov, SY Martner, BE Kropfli, RA TI Dual-polarization radar to identify drizzle, with applications to aircraft icing avoidance SO JOURNAL OF AIRCRAFT LA English DT Article ID WINTER STORMS; CLOUD; PERFORMANCE; PROJECT; SHAPE; DROPS; WIND AB Freezing drizzle has been identified as a primary aircraft in-flight icing hazard. New evidence shows that it can be a greater hazard than freezing rain, even though the latter can be significant. Freezing drizzle may form by droplet coalescence without an intermediate melting process, so that it also can be more difficult to detect than freezing rain. Theoretical calculations of microwave scattering and verification by the initial field studies presented here demonstrate that freezing drizzle should be detectable and distinguishable from other hydrometeor types in short-wavelength, dual-polarization radar measurements of elliptical and linear depolarization ratios. A practical procedure is suggested for identifying and monitoring this aviation hazard with the radar and concurrent atmospheric temperature measurements. The WSR-88D radar (NEXRAD) has the potential to add dual-linear polarization to operationally apply this method, within certain constraints. RP Reinking, RF (reprint author), NOAA,RADAR METEOROL & OCEANOG DIV,ENVIRONM TECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 28 TC 10 Z9 10 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD NOV-DEC PY 1997 VL 34 IS 6 BP 778 EP 784 DI 10.2514/2.2243 PG 7 WC Engineering, Aerospace SC Engineering GA YK024 UT WOS:A1997YK02400011 ER PT J AU Winchester, MR Maul, C AF Winchester, MR Maul, C TI On the determination of carbon, phosphorus, sulfur and silicon in grey cast irons using glow discharge optical emission spectrometry SO JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY LA English DT Article DE analytical bins; cast iron; glow discharge optical emission spectrometry; metalloids; non-metallic elements AB Glow discharge optical emission spectrometry is used to determine C, P, S and Si in grey cast irons, White cast irons are used as calibrants, and data are acquired while sputtering is non-stoichiometric. Type standardization is employed to correct the resulting matrix effect, For comparison, analytical mass fractions of P, S and Si are also calculated from the data while omitting the matrix effect correction, A statistical evaluation of the data shows that,while all except one of the experimental mass fractions, computed with or without type standardization, are in agreement with corresponding certified values at the P = 0.05 level of significance, the use of the type standard is indispensible for the unbiased determination of C and S and may be helpful in the case of P, In contrast, the data indicate that type standardization may in some cases introduce analytical bias into the determination of Si. C1 LECO CORP,ST JOSEPH,MI 49085. RP Winchester, MR (reprint author), NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,DIV ANALYT CHEM,GAITHERSBURG,MD 20899, USA. NR 11 TC 5 Z9 5 U1 1 U2 3 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0267-9477 J9 J ANAL ATOM SPECTROM JI J. Anal. At. Spectrom. PD NOV PY 1997 VL 12 IS 11 BP 1297 EP 1305 DI 10.1039/a702873c PG 9 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA YG295 UT WOS:A1997YG29500009 ER PT J AU Dobson, JEF McClure, FD Rainosek, AP AF Dobson, JEF McClure, FD Rainosek, AP TI Determination of fish flesh content in frozen coated fish products (modification of AOAC Official Method 971.13): Collaborative study SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article AB An intralaboratory(1) collaborative study evaluated a modified version of AOAC Official Method 971.13 for determining the fish flesh content (FFC) in frozen coated fish products by comparing it with the on-line method, Eleven collaborators analyzed 36 products (a total of 6336 test samples), Each product targeted one of 4 percent fish flesh (PFF) levels (35, 50, 65, and 80), Products were manufactured from one of 3 raw materials (fillet blocks, minced blocks, and natural fillets) and processed in one of 4 forms (sticks, portions, formed portions, and fillets) and one of 4 styles (raw breaded, batter-dipped, precooked, and fully cooked). Each ''official'' test sample was tracked through the processing system and weighed (1) before battering and/or breading and, depending on product style, before frying; and (2) after battering and/or breading and, depending on product style, after frying; so that it served as its own control, These weights were used to calculate actual percent fish flesh (APFF) and considered to be generated by the on-line method. Collaborators weighed official test samples (1) before scraping; and (2) after scraping, These weights were used to calculate determined percent fish flesh (DPFF) and considered to be generated by the modified AOAC method, APFF and DPFF were the primary data for statistical analysis, Recoveries ranged from 71.75 to 106.40%, Repeatability (method precision indicator for a single collaborator) relative standard deviation (RSDr) values ranged from 1.04 to 8.37%, Corresponding reproducibility (method precision indicator among collaborators) relative standard deviation (RSDR) values ranged from 1.41 to 11.95%, The DPFF mean was lower than the APFF mean for 30 (83.33%) of 36 products, For 29 of these 30 products, the differences between method means (APFF minus DPFF) ranged from 0.38 to 6.51%, For the remaining product within this group (C/06, fillet blocks, fully cooked portions), the difference between method means was 21.73%. For the remaining 6 (16.67%) of 36 products, the DPFF mean was greater than the APFF mean, The differences between method means ranged from -0.03 to -2.76%. RSD values were considered acceptable (i.e., RSDr < 9% and RSDR < 12%) for all products studied, The modified method for determining FFC in frozen coated fish products has been adopted first action to replace AOAC Official Method 971.13. C1 US FDA,CTR FOOD SAFETY & APPL NUTR,US DEPT HLTH & HUMAN SERV,OFF SCI ANAL & SUPPORT,DIV MATH,WASHINGTON,DC 20204. UNIV S ALABAMA,DEPT MATH & STAT,MOBILE,AL 36688. NATL MARINE FISHERIES SERV,US DEPT COMMERCE,NATL OCEAN & ATMOSPHER ADM,NATL SEAFOOD INSPECT LAB,PASCAGOULA,MS 39568. RP Dobson, JEF (reprint author), NATL MARINE FISHERIES SERV,US DEPT COMMERCE,NATL OCEAN & ATMOSPHER ADM,TECH SERV BRANCH,GLOUCESTER,MA 01930, USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU AOAC INTERNATIONAL PI GAITHERSBURG PA 481 NORTH FREDRICK AVE, STE 500, GAITHERSBURG, MD 20877-2504 SN 1060-3271 J9 J AOAC INT JI J. AOAC Int. PD NOV-DEC PY 1997 VL 80 IS 6 BP 1235 EP 1271 PG 37 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA YL259 UT WOS:A1997YL25900014 PM 9419864 ER PT J AU Zhang, JZ AF Zhang, JZ TI Distinction and quantification of carry-over and sample interaction in gas segmented continuous flow analysis SO JOURNAL OF AUTOMATIC CHEMISTRY LA English DT Article AB The formulae for calculation of carry-over and sample intel action are derived for the first time in this study. A scheme proposed by Thiers et al. (two samples of lore, concentration followed by a high concentration sample and bow concentration sample) is verified and recommended for the determination of the carry-over coefficient. The derivation demonstrates that both widely used schemes of a high concentration sample followed by two low concentration samples, and a low concentration sample followed by two high concentration samples actually measure the sum of the carry-over coefficient and sample interaction coefficient. A scheme of three lore, concentration samples followed by a high concentration sample is proposed and verified for determination of the sample interaction coefficient. Experimental results indicate that carry-over is a strong function of cycle time and a weak function of ratio of sample time to wash time. Sample dispersion is found to be a function of sample time. Fitted equations can be used to predict the carry-over, absorbance and dispersion given sample times, and wash times for an analytical system. Results clearly show the important role of intersample air segmentation in reducing carry-over, sample interaction and dispersion. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, NOAA,AOML, Cooperat Inst Marine & Atmospher Studies, Miami, FL 33149 USA. RP Zhang, JZ (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, NOAA,AOML, Cooperat Inst Marine & Atmospher Studies, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI Zhang, Jia-Zhong/B-7708-2008 OI Zhang, Jia-Zhong/0000-0002-1138-2556 NR 18 TC 15 Z9 15 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0142-0453 J9 J AUTOM CHEM JI J. Autom. Chem. PD NOV-DEC PY 1997 VL 19 IS 6 BP 205 EP 212 DI 10.1155/S1463924697000254 PG 8 WC Biochemical Research Methods; Chemistry, Multidisciplinary; Instruments & Instrumentation SC Biochemistry & Molecular Biology; Chemistry; Instruments & Instrumentation GA YM297 UT WOS:000071049500003 PM 18924810 ER PT J AU Weber, LA Defibaugh, DR AF Weber, LA Defibaugh, DR TI Derivation of the bubble pressure surface, P(x,T), of a binary mixture by ebulliometry: The system C3H3F5 plus C4H2F8 SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID COEFFICIENTS AB A high-pressure metal ebulliometer has been used to determine the infinite dilution activity coefficients for the azeotropic binary system 1,1,2,2,3-pentafluoropropane (HFC245ca) + 1,1,1,2,2,3,3,4-octofluorobutane (HFC338mccq) over the temperature range 300 K to 375 K. Pressures ranged from 98 kPa to 970 kPa. These results, combined with previously determined vapor pressures of the pure components,. the Wilson activity coefficient model for the Liquid, and a virial coefficient model for the vapor, allowed the calculation of the dew and bubble curves over the experimental temperature range. RP Weber, LA (reprint author), NIST,CHEM SCI & TECHNOL LAB,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899, USA. NR 10 TC 1 Z9 1 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 NOV-DEC PY 1997 VL 42 IS 6 BP 1187 EP 1190 DI 10.1021/je960335p PG 4 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA YG659 UT WOS:A1997YG65900030 ER PT J AU Lofgren, BM AF Lofgren, BM TI Simulated effects of idealized Laurentian Great Lakes on regional and large-scale climate SO JOURNAL OF CLIMATE LA English DT Article ID AGGREGATE MESOSCALE DISTURBANCES; HEAT-STORAGE; SENSITIVITY; MICHIGAN; MODEL AB Comparison is made between general circulation model (GCM) cases with and without the inclusion of idealized Great Lakes, in the form of four rectangular bodies of water, each occupying a single grid cell of the GCM at R30 resolution. The presence of idealized Great Lakes, as opposed to land, results in a phase shift in the annual cycle of latent and sensible heat flux. Very high upward sensible heat flux occurs over these idealized Great Lakes during the early winter. On the average over a region encompassing these idealized Great Lakes, evaporation and precipitation increase during the autumn and winter and decrease during the late spring and summer due to the lakes. Annual average water vapor flux convergence increases. The Great Lakes also alter the meridional air temperature gradient. During the autumn and winter, the meridional temperature gradient is intensified to the north of the Great Lakes and diminished to the south. This intensifies the mean jet stream core and displaces it toward the north. This effect is reduced during the winter compared to the autumn because air temperature changes due to the lakes are unable to penetrate as deeply into the strongly stably stratified winter atmosphere. The increase in jet stream speed seems to increase synoptic wave activity to the northeast of the Great Lakes. As an additional experimental case, a swamp surface (saturated surface with no thermal capacity) is used to represent the Great Lakes. In this case there is little effect on the thermal state of the surface and atmosphere and on the fluxes between them. However, there is increased evaporation during the late summer and early autumn and increased precipitation throughout the summer and autumn. Annual water vapor flux convergence in this experimental case is greater than in the case with no lakes. RP Lofgren, BM (reprint author), NOAA,GREAT LAKES ENVIRONM RES LAB,ERL,2205 COMMONWEALTH BLVD,ANN ARBOR,MI 48105, USA. OI Lofgren, Brent/0000-0003-2189-0914 NR 23 TC 36 Z9 40 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 NOV PY 1997 VL 10 IS 11 BP 2847 EP 2858 DI 10.1175/1520-0442(1997)010<2847:SEOILG>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YH745 UT WOS:A1997YH74500010 ER PT J AU Hoerling, MP Kumar, A AF Hoerling, MP Kumar, A TI Origins of extreme climate states during the 1982-83 ENSO winter SO JOURNAL OF CLIMATE LA English DT Article ID NORTHERN-HEMISPHERE; SEASONAL PREDICTIONS; SOUTHERN OSCILLATION; TEMPERATURE; CIRCULATION; PATTERNS; PRECIPITATION; PROSPECTS AB The origin of extreme climate states during the exceptional 1982-83 El Nino event has continued to be a source of controversy and debate. On the one hand, empirical analyses of extratropical climate patterns during past El Nino events suggests the observed anomalies during 1982-83 were consistent with tropical forcing. On the other hand, the large amplitude of those anomalies have not been replicated in atmospheric general circulation mod (AGCM) simulations for that period performed as part of the Atmospheric Model Intercomparison Project (AMIP). It has recently become apparent, however, that the sea surface boundary conditions used to drive the multitude of AMIP simulations were deficient, in that at least 30% of available tropical Pacific SST observations were discarded in the analysis cycle due to excessive trimming constraints. It is shown from a reanalysis of the sea surface temperatures that the observed east equatorial Pacific waters were 1.5 degrees C warmer than original estimates. In order to address the extent to which simulations of the extratropical climate of 1982-83 are sensitive to different SST analyses of that period, a parallel suite of AGCM simulations using two SST prescriptions is performed. One set is based on the blended satellite-in situ data used also in the AMIP runs, whereas the other is based on the optimum interpolation (OI) reanalysis. A nine-member ensemble of such simulations is performed, and this is compared with observations. The model response using the original blended SSTs is shown to severely underestimate the tropical rainfall anomalies, and this contributes to the simulation of a weak extratropical response as reported earlier in the AMIP experiments. A larger, more realistic response during 1982-83 is shown to occur in an identical set of runs based on che OI SST boundary conditions, and most aspects of the observed pattern and strength of the Pacific-North American climate anomalies during that winter are reproduced in the model's ensemble mean response. Further analysis of the models' intersample variability are performed to ascertain the extent to which the observed anomalies may have been influenced by atmospheric initial conditions. It is shown from the OI runs that the observed tropical Pacific rainfall anomalies and the Southern Oscillation index were phenomena causally determined by the El Nino. Even over the Pacific-North American region, the spatial pattern of the anomalies in individual runs was highly reproducible, and several members of the OI runs achieved climate anomalies exceeding in amplitude those observed. The findings strongly indicate the important role of El Nino in determining the climate state over the Pacific-North American region during 1882-83, and various competing hypotheses are critiqued in light of these new model results. C1 NOAA, NCEP, WASHINGTON, DC USA. RP Hoerling, MP (reprint author), UNIV COLORADO, CIRES, CLIMATE DIAG CTR, CAMPUS BOX 449, BOULDER, CO 80309 USA. NR 34 TC 28 Z9 28 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD NOV PY 1997 VL 10 IS 11 BP 2859 EP 2870 DI 10.1175/1520-0442(1997)010<2859:OOECSD>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YH745 UT WOS:A1997YH74500011 ER PT J AU Ott, AK Casey, SM Leone, SR AF Ott, AK Casey, SM Leone, SR TI Laser ionization mass spectrometry measurements of arsenic sticking and incorporation during GaAs(100) homoepitaxy SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE GaAs(100); mass spectrometry; arsenic incorporation; sticking probability ID MOLECULAR-BEAM EPITAXY; ENERGY ELECTRON-DIFFRACTION; INTENSITY OSCILLATIONS; INTERACTION KINETICS; RHEED OBSERVATIONS; MBE GROWTH; GAAS; REFLECTION; AS4; SURFACES AB The fluxes of Ca, As-4 and As-2 desorbed or scattered from a GaAs(1 0 0) surface are monitored with laser single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS) during homoepitaxy of GaAs(1 0 0) with incident As-4 and Ga molecular beams. When the Ga flux is opened to the surface under a constant incident arsenic flux, the observed decrease in the scattered As-4 and As-2 mass signals are a measure of the arsenic incorporation into the growing GaAs layers. Simultaneous reflection high-energy electron diffraction (RHEED) oscillations measured during epitaxy are used to quantify the arsenic and gallium fluxes. The sticking probability for As-4 molecules on the GaAs surface is measured over a range of As-4 and Ga incident fluxes and for the substrate temperature range 600-900 K. At substrate temperatures and under flux conditions in which RHEED specular beam intensity oscillations are observed during epitaxy, the maximum sticking probability for As-4 exceeds the often-quoted value of 0.5, with values observed greater than 0.8. At higher substrate temperatures and under flux conditions in which Ga islands are present on the GaAs surface, the maximum sticking probability of As-4 is 0.5. The sticking probability of As-4 On the GaAs surface decreases with increasing surface temperature. C1 NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,QUANTUM PHYS DIV,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NR 23 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD NOV PY 1997 VL 181 IS 4 BP 326 EP 336 DI 10.1016/S0022-0248(97)00295-9 PG 11 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA YH192 UT WOS:A1997YH19200002 ER PT J AU Garrett, ES Jahncke, ML Tennyson, JM AF Garrett, ES Jahncke, ML Tennyson, JM TI Microbiological hazards and emerging food-safety issues associated with seafoods SO JOURNAL OF FOOD PROTECTION LA English DT Article; Proceedings Paper CT ILSI Symposium on Ensuring a Safe Global Food Supply at the 83rd IAMFES Annual Meeting CY JUN 30-JUL 03, 1996 CL SEATTLE, WA SP ILSI N Amer, Tech Comm Food Microbiol, Int Assoc Milk Food & Environm Sanitorians DE seafood safety; seafood microbial hazards; coastal health AB The United States is entering into a new era in which dwindling natural fisheries resources are forcing regulatory agencies to develop a more holistic approach to seafood safety and natural marine resource issues. Public health issues associated with seafoods can be grouped as (i) environmentally induced (i.e., natural or anthropogenic), (ii) process-induced, (iii) distribution-induced, or (iv) consumer-induced hazards. Similarly, loss of habitat and ecosystem degradation threaten the future viability of fisheries and have important ramifications for seafood safety. In the United States, large-scale legistlative efforts are underway to reexamine regulatory food control systems. The driving forces behind these efforts are the discovery of new emerging pathogens for which little information is available and dramatic improvements in analytic technology that allow for detection of low levels of microbial and chemical contaminants in foods. The global nature of seafood trading issues and the worldwide implementation of new preventative food safety programs such as hazard analysis for critical control points are driving some of the efforts to build new scientific bridges that will reevaluate current risk analysis strategies. New scientific bridges are needed to close the gaps between the scientific community and society concerning the effects of anthropogenic impacts on seafood safety and the heatlh of coastal habitats and associated fishery resources. The driving force behind this latter issue is the realization that the United States has lost over half of its original coastal wetlands areas. Protecting, conserving, and restoring the health and safety of our fisheries resources will require an integrated approach of food science and fishery science. RP Garrett, ES (reprint author), NATL MARINE FISHERIES SERV, NATL SEAFOOD INSPECT LAB, 3209 FREDERIC ST, PASCAGOULA, MS 39567 USA. NR 44 TC 12 Z9 12 U1 0 U2 4 PU INT ASSOC FOOD PROTECTION PI DES MOINES PA 6200 AURORA AVE SUITE 200W, DES MOINES, IA 50322-2863 USA SN 0362-028X J9 J FOOD PROTECT JI J. Food Prot. PD NOV PY 1997 VL 60 IS 11 BP 1409 EP 1415 PG 7 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA YH532 UT WOS:A1997YH53200022 ER PT J AU Vandas, M Fischer, S Pelant, P Dryer, M Smith, Z Detman, T AF Vandas, M Fischer, S Pelant, P Dryer, M Smith, Z Detman, T TI Propagation of a spheromak .1. Some comparisons of cylindrical and spherical magnetic clouds SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-FLARES; MODELS; LOOP; MAGNETOSPHERE; DYNAMICS; PLASMA; SHOCK AB A series of our papers in the Journal of Geophysical Research, 1995-1996, was devoted to simulations of propagation of cylindrical magnetic clouds (flux ropes) having different orientation of their axes to the ecliptic plane and initial parameters. In this paper we supplement our study with the case of detached spherical plasmoids. By varying the velocity, density, temperature, and the magnetic field strength inside clouds, we simulate a number of plasmoid scenarios that can be compared with observations and with existing models and simulations of flux ropes. Initially, the spherical clouds have a poloidal magnetic field configuration within a sphere. During the propagation they evolve into toroids (i.e., closed flux ropes). Radial profiles of magnetic field and plasma quantities in these toroids are similar to cylindrical magnetic clouds. However, they are different in the central (now external) part of the cloud, where the poloidal axis was originally situated, that is, in the toroid's hole. Here the magnetic field is greatly enhanced but does not rotate, and the temperature decrease is absent. The deceleration and transit time to 1 AU is comparable between spherical and cylindrical clouds. The shock wave ahead of a spherical cloud is about 2 times closer than for a corresponding cylindrical cloud. C1 NOAA,SPACE ENVIRONM CTR,R E SE,BOULDER,CO 80303. RP Vandas, M (reprint author), ACAD SCI CZECH REPUBL,INST ASTRON,BOCNI II 1401,PRAGUE 14131 4,CZECH REPUBLIC. RI Vandas, Marek/G-9054-2014; xue, yansheng/A-9712-2012 NR 33 TC 15 Z9 16 U1 0 U2 1 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 NOV 1 PY 1997 VL 102 IS A11 BP 24183 EP 24193 DI 10.1029/97JA02257 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YE924 UT WOS:A1997YE92400016 ER PT J AU WongNg, W Cook, LP Jiang, F Greenwood, W Balachandran, U Lanagan, M AF WongNg, W Cook, LP Jiang, F Greenwood, W Balachandran, U Lanagan, M TI Subsolidus phase equilibria of coexisting high-T-c Pb-2223 and 2212 superconductors in the (Bi,Pb)-Sr-Ca-Cu-O system under 7.5% O-2 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID OXYGEN PARTIAL-PRESSURE; COMPOSITE CONDUCTORS; CRYSTAL-CHEMISTRY; FORMATION MECHANISM; TEXTURE FORMATION; CLAD (BI; SILVER; STABILITY; TAPES; AG AB The subsolidus phase relationships of the high-ir, 2223 superconductor in the (Bi, Pb)-Sr-Ca-Cu-O (BSCCO) system have been examined at 810-820 degrees C, All experiments were carried out at ambient pressure in a 7.5% 0(2) (92.5% Ar) atmosphere. Eleven phases were found to exist in equilibrium with the 2223 phase. These 11 phases include CuO and 10 oxide solid solutions. From among; these phases, a total of 48 five-phase combinations including the 2223 and 2212 phases were investigated experimentally, and 16 equilibrium assemblages were found which define a multicomponent compositional space corresponding to the 2223 + 2212 solid-state compatibility region. The subsolidus data form a partial basis for future investigation of the Pb-2223 primary phase field. C1 UNIV MARYLAND, DEPT GEOL, COLLEGE PK, MD 20742 USA. ARGONNE NATL LAB, DIV ENERGY TECHNOL, ARGONNE, IL USA. RP WongNg, W (reprint author), NIST, DIV CERAM, GAITHERSBURG, MD 20899 USA. NR 86 TC 20 Z9 21 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD NOV PY 1997 VL 12 IS 11 BP 2855 EP 2865 DI 10.1557/JMR.1997.0379 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA YG457 UT WOS:A1997YG45700003 ER PT J AU Kaiser, DL Turchinskaya, M Riley, GN Christopherson, C AF Kaiser, DL Turchinskaya, M Riley, GN Christopherson, C TI Effect of filament architecture on magnetic flux distributions in multifilamentary (Bi,Pb)(2)Sr2Ca2Cu3Ox/Ag composites SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID TAPES; PENETRATION; POLYCRYSTALS; GRANULARITY; CONDUCTORS; BOUNDARIES AB Multifilamentary (Bi, Pb)(2)Sr2Ca2Cu3Ox/Ag composites have been studied by a nondestructive magneto-optical imaging technique in order to determine the effect of filament architecture on the local magnetic flux distribution. The images reveal the homogeneity of the flux distribution in the upper layer filaments under magnetizing and demagnetizing conditions, and the alignment and morphology of these filaments in tapes with nine different composite structures. Certain types of filament arrangements led to homogeneous flux distributions, while other types caused localized inhomogeneities in the flux distribution. Nonuniform filament thickness also resulted in a highly inhomogeneous flux distribution. These results are useful in selecting optimal composite structures for power applications. C1 AMER SUPERCONDUCTOR,WESTBOROUGH,MA 01581. RP Kaiser, DL (reprint author), NATL INST STAND & TECHNOL,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 19 TC 4 Z9 4 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD NOV PY 1997 VL 12 IS 11 BP 3074 EP 3084 DI 10.1557/JMR.1997.0400 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA YG457 UT WOS:A1997YG45700024 ER PT J AU Wang, PS AF Wang, PS TI NMR characterization of silicon nitride: slurry homogeneity by T-2-weighted proton imaging SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID ALUMINA GREEN COMPACTS; BINDER DISTRIBUTION; CERAMICS AB The Si3N4/water slurries were studied by proton nuclear magnetic resonance (H-1 NMR) imaging for homogeneity. H-1 nuclear spin echo signals from Si3N4/water slurries were observed by a (pi/2)-tau-pi-tau-echo pulse sequence. Bloch's equations were used to calculate the spin-spin relaxation times (T-2) from these echo intensities. The T-2 for the protons in these slurries was measured to be 53.7 +/- 0.1 ms. The T-2-weighted imaging technique utilizing (pi/2)-tau-pi-tau multiple pulse sequence was mixed with a ''shape pulse'' for radio frequency (RF)-excitation to detect nuclear spin echo signals for image construction. Sinc shape pulses were used to mix with both the (pi/2) and the pi pulses as a frequency carrier because of the mobility of water molecules in the slurry. The nuclear spin echo intensities were transformed into three-dimensional pictures by magnetic field gradients generated by coils along x, y and z-co-ordinates. Axial-section slices were taken to map the water distribution of the slurry in an NMR tube. A stable and well-dispersed Si3N4/H2O slurry, With ammonium polymethacrylate as dispersant, was observed for several hours. Agglomerization of this slurry was detected after 15 h of standing and NMR imaging shown in contour plots depicted clearly the location and the degree of agglomerization. The water distribution can also be presented in three dimensions by stack plotting of the water intensity profiles. RP Wang, PS (reprint author), NIST,DIV CERAM,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899, USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD NOV 1 PY 1997 VL 32 IS 21 BP 5697 EP 5702 DI 10.1023/A:1018657415190 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA YE928 UT WOS:A1997YE92800017 ER PT J AU Leibfried, D Meekhof, DM Monroe, C King, BE Itano, WM Wineland, DJ AF Leibfried, D Meekhof, DM Monroe, C King, BE Itano, WM Wineland, DJ TI Experimental preparation and measurement of quantum states of motion of a trapped atom SO JOURNAL OF MODERN OPTICS LA English DT Article ID MECHANICAL STATE; SQUEEZED STATES; ION-TRAP; TOMOGRAPHY; MODEL; FLUORESCENCE; DECOHERENCE; REVIVAL; VACUUM AB We report the creation and full determination of several quantum states of motion of a Be-9(+) ion bound in a RF (Paul) trap. The states are coherently prepared from an ion which has been initially laser cooled to the zero-point of motion. We create states having both classical and non-classical character including thermal, number, coherent, squeezed, and 'Schrodinger cat' states. The motional quantum state is fully reconstructed using two novel schemes that determine the density matrix in the number slate basis or the Wigner function. Our techniques allow well controlled experiments decoherence and related phenomena on the quantum-classical borderline. RP Leibfried, D (reprint author), NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,325 BROADWAY,BOULDER,CO 80303, USA. RI Monroe, Christopher/G-8105-2011 NR 54 TC 73 Z9 73 U1 1 U2 11 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD NOV-DEC PY 1997 VL 44 IS 11-12 BP 2485 EP 2505 DI 10.1080/09500349708231896 PG 21 WC Optics SC Optics GA YH586 UT WOS:A1997YH58600034 ER PT J AU Atkinson, R Baulch, DL Cox, RA Hampson, RF Kerr, JA Rossi, MJ Troe, J AF Atkinson, R Baulch, DL Cox, RA Hampson, RF Kerr, JA Rossi, MJ Troe, J TI Evaluated kinetic and photochemical data for atmospheric chemistry: Supplement VI - IUPAC subcommittee on gas kinetic data evaluation for atmospheric chemistry SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE air pollution; atmospheric chemistry; chemical kinetics; data evaluation; gas phase; photoabsorption cross-section, photochemistry; quantum yield; rate coefficient ID THERMAL UNIMOLECULAR REACTIONS; COLLISION RATE CONSTANTS; CODATA TASK GROUP; FALL-OFF RANGE; CHEMICAL-KINETICS AB This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997)]. The present evaluation is limited to the following families of atmospherically important reactions: O-x, HOx, NOx, and SOx. 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 151 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross-sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available data on enthalpies of formation of the reactant and product species. (C) 1997 American Institute of Physics and American Chemical Society. [S0047-2689(97)00106-2]. C1 UNIV CALIF RIVERSIDE,DEPT SOIL & ENVIRONM SCI,RIVERSIDE,CA 92521. UNIV CALIF RIVERSIDE,DEPT CHEM,RIVERSIDE,CA 92521. UNIV LEEDS,SCH CHEM,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND. UNIV CAMBRIDGE,DEPT CHEM,CTR ATMOSPHER SCI,CAMBRIDGE CB2 1EW,ENGLAND. NIST,CHEM KINET DATA CTR,GAITHERSBURG,MD 20899. UNIV BIRMINGHAM,SCH CHEM,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND. ECOLE POLYTECH FED LAUSANNE,LAB POLLUT ATMOSPHER & SOL,IGR,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 11 TC 445 Z9 450 U1 5 U2 77 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD NOV-DEC PY 1997 VL 26 IS 6 BP 1329 EP 1499 PG 171 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA YK508 UT WOS:A1997YK50800002 ER PT J AU Domalski, ES Hearing, ED AF Domalski, ES Hearing, ED TI Heat capacities and entropies of organic compounds in the condensed phase, vol 3 (vol 25, pg 1, 1996) SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article AB The errata are arranged in the format shown below and are listed as found according to successive pages in the 1996 publication, J. Phys. Chem. Ref. Data 25, 1-525 (1996). After the page number for a specific erratum, which is shown on the extreme left side of the first Line, information is provided regarding its location on a given page, such as: compound formula, compound name, reference squib, or other pertinent information. On the second line, the erratum appears as found in the publication. On the third line, one finds the correction. The last line offers a comment or explanation about the erratum. (C) 1997 American Institute of Physics and American Chemical Society. [S0047-2689(97)00206-7]. RP Domalski, ES (reprint author), NIST,DIV CHEM KINET & THERMODYNAM,GAITHERSBURG,MD 20899, USA. NR 1 TC 1 Z9 1 U1 1 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD NOV-DEC PY 1997 VL 26 IS 6 BP 1501 EP 1505 PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA YK508 UT WOS:A1997YK50800003 ER PT J AU Johnson, GC Moore, DW AF Johnson, GC Moore, DW TI The Pacific subsurface countercurrents and an inertial model SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID WESTERN EQUATORIAL PACIFIC; INTERMEDIATE WATER; UNDERCURRENT; OCEAN; CIRCULATION; VARIABILITY; TERMINATION; DYNAMICS; CURRENTS AB The Tsuchiya jets. or subsurface countercurrents, extend across the Pacific Ocean carrying 7 (+/-2) x 10(6) m(3) s(-1) eastward on each side of the equator. Mean meridional sections of potential temperature, salinity, neutral density anomaly, and the square of buoyancy frequency are presented for the western. central, and eastern tropical Pacific Ocean. These sections are used together with maps of depth and salinity on isopycnals, as well as thickness between isopycnals, to describe the evolution of the Tsuchiya jets as they flow from west to east. An inertial-jet model is formulated in which conservation of the Bernoulli function and potential vorticity combine with the eastward shoaling of the tropical pycnocline to dictate the jet structure. This model jet is consistent with a number of features of the Tsuchiya jets: their roughly constant volume transports. their advection of properties such as salinity and oxygen over long zonal distances. their rapidity and narrowness, their poleward shift from west to east, the large potential vorticity gradients across them, and the pycnostad between them that builds in size and strength from west to east. However. an observed decrease in density carried by the Tsuchiya jets from west to east, not included in the model jet, suggests that diffusive or advective interaction with the surrounding ocean also may be important in subsurface countercurrent dynamics. RP Johnson, GC (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,7600 SAND POINT WAY NE,BLDG 3,SEATTLE,WA 98115, USA. RI Johnson, Gregory/I-6559-2012; MOORE, DENNIS/C-9901-2014 OI Johnson, Gregory/0000-0002-8023-4020; NR 23 TC 38 Z9 40 U1 1 U2 4 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 NOV PY 1997 VL 27 IS 11 BP 2448 EP 2459 DI 10.1175/1520-0485(1997)027<2448:TPSCAA>2.0.CO;2 PG 12 WC Oceanography SC Oceanography GA YF289 UT WOS:A1997YF28900010 ER PT J AU Zimmerman, BE Unterweger, MP Cessna, JT AF Zimmerman, BE Unterweger, MP Cessna, JT TI The half-life of Cu-62 SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article AB The half-life of the positron emitter (CU)-C-62 has been measured using 4 pi beta liquid scintillation (LS) spectrometry and counting in the National Institute of Standards and Technology (NIST) '4 pi'-gamma re-entrant ionization chamber (IC). A total of 12 independent LS measurements and two independent IC measurements were made, all of which spanned two to four half-lives. Weighted nonlinear fits of the data resulted in half-lives of 9.68 min +/- 0.04 min and 9.673 min +/- 0.026 min (uncertainties are combined standard uncertainties) for the LS and IC data, respectively (a difference of only 0.07%). The weighted mean of these two values is 9.67 min +/- 0.03 min, which is shorter than the ENSDF-recommended value of 9.74 min +/- 0.02 min by 0.7%. Since this radionuclide is being investigated for use in positron emission tomography (PET), this difference in the half-life has an important effect on the estimation of the amount of radioactivity administered to patients when decay corrections must be applied. RP Zimmerman, BE (reprint author), NATL INST STAND & TECHNOL,PHYS LAB,GAITHERSBURG,MD 20899, USA. NR 14 TC 6 Z9 6 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD NOV PY 1997 VL 23 IS 11 BP 1707 EP 1714 DI 10.1088/0954-3899/23/11/018 PG 8 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA YG224 UT WOS:A1997YG22400018 ER PT J AU Rana, MD Smith, JH Tribolet, RO AF Rana, MD Smith, JH Tribolet, RO TI Technical basis for flawed cylinder test specification to assure adequate fracture resistance of ISO high-strength steel cylinder SO JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Pressure Vessels and Piping Conference CY JUL 21-26, 1996 CL MONTREAL, CANADA SP Amer Soc Mech Engineers AB High-pressure industrial gases(such as oxygen, nitrogen, argon, hydrogen, etc.) are stared and transported in portable cylinders. ISO TC58 SC3 has developed a draft specification 9809 for design and fabrication of high-pressure cylinders with maximum tensile strength limitation of 1100 N/mm(2). In order to extend the ISO 9809 rules for higher than 1100 N/mm(2) strength level cylinders, a working group WG14 was formed in 1989 to develop new rules to assure adequate fracture resistance. In 1994, WG14 recommended a simple, but unique flawed cylinder test method for design qualification of the cylinder and acceptance criteria to assure adequate fracture resistance. WG14 also recommended Charpy-V-notch impact tests to control the required fracture resistance opt production cylinders. This paper presents the technical basis that was employed in developing the flawed cylinder rest method and acceptance criteria. The specification was developed for seamless steel cylinders having actual strength in the range of 1100 to 1400 N/mm(2) and cylindrical section wall thickness in the range of 3 to 10 mm. Flawed cylinder tests were conducted on several hundred cylinders of varying sizes and strength levels. The specification requires to demonstrate LEAK-BEFORE-BREAK performance of the cylinder having flaw length equal to 1.6 (o.d. x t(design))(0.5) at failure pressure = (t(design)/t(actual)) x Design Pressure. C1 NATL INST STAND & TECHNOL,DIV MET,GAITHERSBURG,MD 20899. RP Rana, MD (reprint author), PRAXAIR INC,PROC & SYST R&D,TONAWANDA,NY 14151, USA. NR 5 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 0094-9930 J9 J PRESS VESS-T ASME JI J. Press. Vessel Technol.-Trans. ASME PD NOV PY 1997 VL 119 IS 4 BP 475 EP 480 DI 10.1115/1.2842332 PG 6 WC Engineering, Mechanical SC Engineering GA YJ016 UT WOS:A1997YJ01600012 ER PT J AU Johnson, BC Sakuma, F Butler, JJ Biggar, SF Cooper, JW Ishida, J Suzuki, K AF Johnson, BC Sakuma, F Butler, JJ Biggar, SF Cooper, JW Ishida, J Suzuki, K TI Radiometric measurement comparison using the Ocean Color Temperature Scanner (OCTS) visible and near infrared integrating sphere SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE calibration; EOS; integrating sphere; measurement comparison; OCTS; ocean color; SeaWiFS; spectral radiometry; remote sensing; transfer radiometers ID CALIBRATION; INSTRUMENT AB As a part of the pre-flight calibration and validation activities for the Ocean Color and Temperature Scanner (OCTS) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) ocean color satellite instruments, a radiometric measurement comparison was held in February 1995 at the NEC Corporation in Yokohama, Japan. Researchers from the National Institute of Standards and Technology (NIST), the National Aeronautics and Space Administration/Goddard Space Right Center (NASA/GSFC), the University of Arizona Optical Sciences Center (UA), and the National Research Laboratory of Metrology (NRLM) in Tsukuba, Japan used their portable radiometers to measure the spec tral radiance of the OCTS visible and near-infrared integrating sphere at four radiance levels. These four levels corresponded to the configuration of the OCTS integrating sphere when the calibration coefficients for five of the eight spectral channels, or bands, of the OCTS instrument were determined. The measurements of the four radiometers differed by -2.7 % to 3.9 % when compared to the NEC calibration of the sphere and the overall agreement was within the combined measurement uncertainties. A comparison of the measurements from the participating radiometers also resulted in agreement within the combined measurement uncertainties. These results are encouraging and demonstrate the utility of comparisons using laboratory calibration integrating sphere sources. Other comparisons will focus on instruments that are scheduled for spacecraft in the NASA study of climate change, the Earth Observing System (EOS). C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Natl Res Lab Metrol, Tsukuba, Ibaraki 305, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. Hughes STX Corp, Greenbelt, MD 20771 USA. NEC Corp Ltd, Div Space Syst, Tsuzuki Ku, Yokohama, Kanagawa 224, Japan. RP Johnson, BC (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Butler, James/D-4188-2013 NR 16 TC 16 Z9 16 U1 1 U2 3 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD NOV-DEC PY 1997 VL 102 IS 6 BP 627 EP 646 DI 10.6028/jres.102.043 PG 20 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YW259 UT WOS:000071914400001 PM 27805113 ER PT J AU Doiron, T Stoup, J AF Doiron, T Stoup, J TI Uncertainty and dimensional calibrations SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE angle standards; calibration; dimensional metrology; gage blocks; gages; optical flats; uncertainty; uncertainty budget ID REFRACTIVE-INDEX; AIR AB The calculation of uncertainty for a measurement is an effort to set reasonable bounds for the measurement result according to standardized rules. Since every measurement produces only an estimate of the answer, the primary requisite of an uncertainty statement is to inform the reader of how sure the writer is that the answer is in a certain range. This report explains how we have implemented these rules for dimensional calibrations of nine different types of gages: gage blocks, gage wires, ring gages, gage balls, roundness standards, optical flats indexing tables, angle blocks, and sieves. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Doiron, T (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 26 TC 17 Z9 17 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 NOV-DEC PY 1997 VL 102 IS 6 BP 647 EP 676 DI 10.6028/jres.102.044 PG 30 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YW259 UT WOS:000071914400002 PM 27805114 ER PT J AU Cage, ME AF Cage, ME TI Current distributions in quantum Hall effect devices SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE conducting channels; flow patterns; distributed currents; edge-channel states; quantum Hall effect; skipping orbits; two-dimensional electron gas ID DIMENSIONAL ELECTRON-SYSTEMS; HIGH MAGNETIC-FIELDS; EDGE CURRENTS; POTENTIAL DISTRIBUTION; BREAKDOWN VOLTAGE; GAAS-ALXGA1-XAS HETEROSTRUCTURES; 2 DIMENSIONS; REGIME; RESISTANCE; GAS AB This paper addresses the question of how current is distributed within quantum Hall effect devices. Three types of flow patterns most often mentioned in the literature are considered. They are: (1) skipping orbits along the device periphery (which arise from elastic collisions off hard-walled potentials); (2) narrow conducting channels along the device sides (which are presumed to be generated from confining potentials); and (3) currents distributed throughout the device (which are assumed to arise from a combination of confining and charge-redistribution potentials). The major conclusions are that skipping orbits do not occur in quantum Hall effect devices, and that nearly all of the externally applied current is located within the device interior rather than along the device edges. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 70 TC 9 Z9 9 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 NOV-DEC PY 1997 VL 102 IS 6 BP 677 EP 691 DI 10.6028/jres.102.045 PG 15 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YW259 UT WOS:000071914400003 PM 27805115 ER PT J AU Kim, YK Ali, MA Rudd, ME AF Kim, YK Ali, MA Rudd, ME TI Electron-impact total ionization cross sections of CH and C2H2 SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE acetylene; hydrocarbon; radical; total ionization cross section ID MODEL AB Electron-impact total ionization cross sections for the CH radical and C2H2 (acetylene), have been calculated using the Binary Encounter-Bethe (BEB) model. The BEB model combines the Mott cross section and the asymptotic form of the Bethe theory, and has been shown to generate reliable ionization cross sections for a large variety of molecules. The BEB cross sections for CH and C2H2 are in good agreement with the available experimental data from ionization thresholds to hundreds of eV in incident energies. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Howard Univ, Dept Chem, Washington, DC 20059 USA. Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. RP Kim, YK (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 11 TC 35 Z9 35 U1 0 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD NOV-DEC PY 1997 VL 102 IS 6 BP 693 EP 696 DI 10.6028/jres.102.046 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YW259 UT WOS:000071914400004 PM 27805116 ER PT J AU Marks, RB Heutmaker, MS AF Marks, RB Heutmaker, MS TI 1997 Wireless Communications Conference - Boulder, CO - August 11-13, 1997 SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Editorial Material C1 Natl Inst Stand & Technol, Div Electromagnet Fields, Elect & Elect Engn Lab, Boulder, CO 80303 USA. Lucent Technol, Princeton, NJ 08542 USA. RP Marks, RB (reprint author), Natl Inst Stand & Technol, Div Electromagnet Fields, Elect & Elect Engn Lab, 325 Broadway, Boulder, CO 80303 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD NOV-DEC PY 1997 VL 102 IS 6 BP 697 EP 702 DI 10.6028/jres.102.047 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YW259 UT WOS:000071914400005 PM 27805117 ER PT J AU Marks, RB Alley, GD AF Marks, RB Alley, GD TI The Automatic Radio Frequency Techniques Group Conference on Characterization of Broadband Telecommunications Components and Systems - Denver, CO - June, 13, 1997 SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Editorial Material C1 Natl Inst Stand & Technol, Div Electromagnet Fields, Elect & Engn Lab, Boulder, CO 80303 USA. Lucent Technol, N Andover, MA 01845 USA. RP Marks, RB (reprint author), Natl Inst Stand & Technol, Div Electromagnet Fields, Elect & Engn Lab, 325 Broadway, Boulder, CO 80303 USA. NR 0 TC 0 Z9 0 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 NOV-DEC PY 1997 VL 102 IS 6 BP 703 EP 707 DI 10.6028/jres.102.048 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YW259 UT WOS:000071914400006 PM 27805118 ER PT J AU Bailey, KM AF Bailey, KM TI Structural dynamics and ecology of flatfish populations SO JOURNAL OF SEA RESEARCH LA English DT Article; Proceedings Paper CT 3rd International Symposium on Flatfish Ecology CY NOV 02-08, 1996 CL NETHERLANDS INST SEA RES, TEXEL, NETHERLANDS SP European Commiss, Programme FAIR, Netherlands Inst Sea Res, Netherlands Inst Fisheries Res, N Carolina State Univ, Royal Netherlands Acad Art & Sci HO NETHERLANDS INST SEA RES DE flatfish; population dynamics; dispersal; metapopulations; genetic structure ID PLAICE PLEURONECTES-PLATESSA; FLOUNDER GLYPTOCEPHALUS-CYNOGLOSSUS; HADDOCK MELANOGRAMMUS-AEGLEFINUS; COD GADUS-MORHUA; STOCK IDENTIFICATION; MITOCHONDRIAL-DNA; GENETIC-STRUCTURE; MARINE TELEOSTS; NORTH-SEA; RECRUITMENT AB The concept of structure in populations of marine fishes is fundamental to how we manage and conduct research on these resources. The degree of population structure ranges widely among flatfishes. Although we know that large populations tend to be subdivided into local populations, based on morphological, meristic and reproductive characteristics, these data often conflict with evidence on genetic stock structure, due to the scale and organization of movement within the metapopulation. Movement of individuals between local subpopulations and colonization events on a microecological scale are probably important to some flatfish populations. Dispersal of larvae is known to be a major factor affecting population mixing. Some flatfishes have planktonic stages of long duration and for these species there is often, but not always, little population structure; gene Bow sometimes may be limited by oceanographic features, such as eddies and fronts. At the juvenile stage dispersal can result in colonization of underutilized habitats; however, for flatfishes with strong habitat requirements. this type of event may be less likely when suitable habitats are fragmented. Complex population structure has major implications for management, e.g. lumping harvested populations with little gene flow can have detrimental local effects. Moreover, the issue of population structure and movement influences the interpretation of research data, where populations are generally treated as closed systems. There is currently a strong need for a multidisciplinary approach to study fish population dynamics and the structure of their populations. This research should involve molecular geneticists, population geneticists, animal behaviourists and ecologists. Migration mechanisms, colonization and extinction events, gene Bow and density-dependent movements are subject areas of great importance to managing large harvested populations, but our understanding of them at ecological scales, at least for marine fishes, is at a rudimentary level. C1 Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Bailey, KM (reprint author), Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM kevin_bailey@racesmtp.afsc.noaa.gov NR 77 TC 43 Z9 45 U1 2 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1385-1101 EI 1873-1414 J9 J SEA RES JI J. Sea Res. PD NOV PY 1997 VL 37 IS 3-4 BP 269 EP 280 DI 10.1016/S1385-1101(97)00018-X PG 12 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA YM253 UT WOS:000071045100009 ER PT J AU Fanney, AH Dougherty, BP Kramp, KP AF Fanney, AH Dougherty, BP Kramp, KP TI Field performance of photovoltaic solar water heating systems SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB Energy consumed for water heating accounts for approximately 17.9 EJ of the energy consumed by residential and commercial buildings. Although there are over 90 million water heaters currently in use within the United Stares (2ogg and Barbour, 1996), durability and installation issues as well as initial cost have limited the sales of solar water heaters to less than I million units. Durability issues have included freeze and fluid leakage problems, failure of pumps and their associated controllers, the loss of heat transfer fluids under stagnation conditions, and heat exchanger fouling. The installation of solar water heating systems has often proved difficult, requiring roof penetrations for the piping that transports fluid to and from the solar collectors. Fanney and Dougherty have recently proposed and patented a solar water heating system that eliminates the durability and installation problems associated with current solar water heating systems. The system employs photovoltaic modules to generate electrical energy which is dissipated in multiple electric heating elements. A microprocessor controller is used to match the electrical resistance of the load to the operating characteristics of the photovoltaic modules. Although currently more expensive than existing solar hot water systems, photovoltaic solar water heaters offer the promise of being less expensive than solar thermal systems within the next decade. To date, photovoltaic solar water heating systems have been installed at the National institute of Standards and Technology in Gaithersburg, MD and the Florida Solar Energy Center in Cocoa, FL. This paper will review the technology employed, describe the two photovoltaic solar water heating systems and present measured performance data. RP Fanney, AH (reprint author), NATL INST STAND & TECHNOL,BLDG ENVIRONM DIV,GAITHERSBURG,MD 20899, USA. NR 8 TC 4 Z9 4 U1 0 U2 1 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 NOV PY 1997 VL 119 IS 4 BP 265 EP 272 DI 10.1115/1.2888031 PG 8 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA YG911 UT WOS:A1997YG91100001 ER PT J AU Simiu, E AF Simiu, E TI Prediction of hurricane wind speeds in the United States - Discussion SO JOURNAL OF STRUCTURAL ENGINEERING-ASCE LA English DT Editorial Material RP Simiu, E (reprint author), NATL INST STAND & TECHNOL,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899, USA. NR 3 TC 1 Z9 1 U1 0 U2 1 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 NOV PY 1997 VL 123 IS 11 BP 1549 EP 1550 DI 10.1061/(ASCE)0733-9445(1997)123:11(1549) PG 2 WC Construction & Building Technology; Engineering, Civil SC Construction & Building Technology; Engineering GA YC375 UT WOS:A1997YC37500017 ER PT J AU Baskin, DM Zimmerman, MH Faber, KT Fuller, ER AF Baskin, DM Zimmerman, MH Faber, KT Fuller, ER TI Forming single-phase laminates via the gelcasting technique SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID THERMAL-EXPANSION ANISOTROPY; DISSIMILAR ELASTIC-MATERIALS; CERAMIC COMPOSITES; CRACK DEFLECTION; INTERFACE; STRESSES; ALUMINA AB Single-phase laminates of iron titanate were formed by gel-casting in both the presence and absence of a magnetic field to produce alternating layers of textured and nontextured microstructure, respectively. X-ray analysis was performed on each lamina verifying that alignment was maintained throughout processing. Tunnel cracks were found in trilayer laminates (nontextured/textured/nontextured) when the alignment direction was parallel to the interface between layers. The cracks are consistent with a stress profile of residual tension parallel to the interface in the textured layer. C1 NIST,DIV CERAM,GAITHERSBURG,MD 20899. RP Baskin, DM (reprint author), NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,ROBERT R MCCORMICK SCH ENGN & APPL SCI,EVANSTON,IL 60208, USA. RI Faber, Katherine/B-6741-2009 NR 17 TC 18 Z9 21 U1 1 U2 5 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD NOV PY 1997 VL 80 IS 11 BP 2929 EP 2932 DI 10.1111/j.1151-2916.1997.tb03213.x PG 4 WC Materials Science, Ceramics SC Materials Science GA YG203 UT WOS:A1997YG20300022 ER PT J AU Farrow, RC Postek, MT Keery, WJ Jones, SN Lowney, JR Blakey, M Fetter, LA Griffith, JE Liddle, JA Hopkins, LC Huggins, HA Peabody, M Novembre, A AF Farrow, RC Postek, MT Keery, WJ Jones, SN Lowney, JR Blakey, M Fetter, LA Griffith, JE Liddle, JA Hopkins, LC Huggins, HA Peabody, M Novembre, A TI Application of transmission electron detection to SCALPEL mask metrology SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 41st International Conference on Electron, Ion, and Photon Beam Technology and Nanofabrication (EIBPN) CY MAY 27-30, 1997 CL DANA POINT, CALIFORNIA SP Amer Vacuum Soc, IEEE, Electron Device Soc, Optical Soc Amer ID LITHOGRAPHY; LINEWIDTH AB Linewidth measurements were performed on a 4X scattering with angular limitation in projection electron lithography (SCALPEL) e-beam lithography mask using the transmitted electron signal in a modified scanning electron microscope. Features as small as 0.24 mu m were measured on the mask. The thin membrane mask structure that was used is found to provide sufficient transmitted signal contrast at energies ranging from 10 to 30 keV. The linewidth measurement accuracy is mostly limited by the variations in the material and not the measurement system. It is concluded that the linewidth measurement technique using transmitted electrons is suitable for the potential certification of SCALPEL mask standards. (C) 1997 American Vacuum Society. C1 AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Farrow, RC (reprint author), AT&T Bell Labs, Lucent Technol, 600 Mt Ave, Murray Hill, NJ 07974 USA. RI Liddle, James/A-4867-2013 OI Liddle, James/0000-0002-2508-7910 NR 7 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 1997 VL 15 IS 6 BP 2167 EP 2172 DI 10.1116/1.589346 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA YM807 UT WOS:000071103100053 ER PT J AU Liddle, JA Blakey, MI Saunders, T Farrow, RC Fetter, LA Knurek, CS Kasica, R Novembre, AE Peabody, ML Tennant, DM Windt, DL Postek, M AF Liddle, JA Blakey, MI Saunders, T Farrow, RC Fetter, LA Knurek, CS Kasica, R Novembre, AE Peabody, ML Tennant, DM Windt, DL Postek, M TI Metrology of scattering with angular limitation projection electron lithography masks SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 41st International Conference on Electron, Ion, and Photon Beam Technology and Nanofabrication (EIBPN) CY MAY 27-30, 1997 CL DANA POINT, CALIFORNIA SP Amer Vacuum Soc, IEEE, Electron Device Soc, Optical Soc Amer ID BEAM LITHOGRAPHY AB Mask metrology is a vital part of any lithographic technology, both for control of the mask patterning process and also for ensuring that the contribution of the mask to the system error budget is within acceptable limits. For design rules of 0.13 mu m and below, errors arising from metrology must be kept to less than 1 nm. We have examined the potential for achieving this, in the case of scattering with angular limitation projection electron lithography (SCALPEL) masks, by using high-energy (100 keV) electron transmission measurements. We have also performed extensive metrology using conventional scanning electron microscope techniques. These results show that the SCALPEL mask has the potential to meet the specifications necessary for lithography at the 0.13 mu m generation and beyond. (C) 1997 American Vacuum Society. C1 AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Liddle, JA (reprint author), AT&T Bell Labs, Lucent Technol, 600 Mt Ave, Murray Hill, NJ 07974 USA. RI Liddle, James/A-4867-2013 OI Liddle, James/0000-0002-2508-7910 NR 9 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 1997 VL 15 IS 6 BP 2197 EP 2203 DI 10.1116/1.589613 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA YM807 UT WOS:000071103100060 ER PT J AU Coxon, B Sari, N Holden, MJ Vilker, VL AF Coxon, B Sari, N Holden, MJ Vilker, VL TI Investigation of the paramagnetic domain of putidaredoxin by nitrogen-15 NMR spectroscopy SO MAGNETIC RESONANCE IN CHEMISTRY LA English DT Article DE N-15 NMR; H-1 NMR; paramagnetic proteins; putidaredoxin; N-15 T-1 values; iron-sulfur cluster; reduced distances ID MULTINUCLEAR MAGNETIC-RESONANCE; SPECIES STRAIN PCC-7120; HYPERFINE-SHIFTED N-15; OXIDIZED FORM; 2FE.2S-STAR FERREDOXIN; COHERENCE-TRANSFER; FE2S2 FERREDOXIN; H-1 RESONANCES; H-1-NMR; PROTEINS AB The oxidized forms of the redox proteins putidaredoxin and putidaredoxin-N-15 were prepared by insertion of suitable plasmids into E. coli and the structures of the proteins were studied by home-and heteronuclear H-1 and N-15 NMR methods, including identification of N-15 resonance types by one-and two-dimensional DEFT spectrum editing and measurements of N-15 chemical shifts, coupling constants, nuclear Overhauser effects and spin-lattice relaxation times. Direct detection of N-15 NMR spectra revealed a number of N-15 resonances that have not been found in previous H-1 detected NMR studies. These resonances include a set of 16 paramagnetically broadened signals from N-15 nuclei that are structurally close to the iron-sulfur cluster of the protein, proline backbone N-15 resonances and N-15 signals from the side-chains of glutamine and Iysine residues. Reduced distances between certain paramagnetically affected N-15 nuclei and the center of the iron-sulfur cluster were calculated from the N-15 spin-lattice relaxation times, based on the assumption of a dominant electron-nuclear dipole-dipole relaxation mechanism. Ranked by size, these distances agree with those computed from coordinates of a published structure of putidaredoxin determined by H-1 NMR and analogy with an Anabaena ferredoxin. (C) 1997 John Wiley & Sons, Ltd. RP Coxon, B (reprint author), NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899, USA. NR 52 TC 6 Z9 6 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0749-1581 J9 MAGN RESON CHEM JI Magn. Reson. Chem. PD NOV PY 1997 VL 35 IS 11 BP 743 EP 751 PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA YG122 UT WOS:A1997YG12200004 ER PT J AU Marinenko, RB Teplitsky, M AF Marinenko, RB Teplitsky, M TI Quantitative electron probe microanalysis of Bi-Sr-Ca-Cu-O high T(c) superconductors using energy- and wavelength-dispersive spectrometry SO MICROSCOPY AND MICROANALYSIS LA English DT Article DE Bi-Sr-Ca-Cu-O superconductor; electron probe microanalyzer; high T(c) superconductors; MLLSQ spectral processing; quantitative EDS analysis; sequential simplex; Bi-Pb simultaneous analysis; EDS spectral processing AB Multiple linear least squares (MLLSQ) and sequential simplex spectral processing procedures were used in an electron probe energy-dispersive (EDS) analysis of a 2223 Bi-Sr-Ca-Cu-O (BSCCO) high T(c) superconductor specimen. This phase is normally difficult to quantify by EDS at voltages below 25 kV because of the severe overlap of the BiM lines with the M lines from a small amount of Pb that is added to the phase for stability. Quantitative results from the MLLSQ spectral processing and ZAF matrix correction procedures agreed well with wavelength-dispersive analysis (WDS) of the same specimen. C1 NIST, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Amer Supercond Corp, Westborough, MA 01581 USA. RP Marinenko, RB (reprint author), NIST, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 9 TC 1 Z9 1 U1 1 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 1431-9276 J9 MICROSC MICROANAL JI Microsc. microanal. PD NOV-DEC PY 1997 VL 3 IS 6 BP 504 EP 511 PG 8 WC Materials Science, Multidisciplinary; Microscopy SC Materials Science; Microscopy GA YR816 UT WOS:000071533100002 ER PT J AU Betts, AK Chen, F Mitchell, KE Janjic, ZI AF Betts, AK Chen, F Mitchell, KE Janjic, ZI TI Assessment of the land surface and boundary layer models in two operational versions of the NCEP Eta Model using FIFE data SO MONTHLY WEATHER REVIEW LA English DT Article ID STEP-MOUNTAIN COORDINATE; PARAMETERIZATION SCHEME; SOLAR-RADIATION; SOIL HYDROLOGY; ECMWF MODEL; MOISTURE; FLUXES; CONVECTION; REANALYSIS; GRASSLAND AB Data from the 1987 summer FIFE experiment for four pairs of days are compared with corresponding 48-h forecasts from two different versions of the Era Model, both initialized from the NCEP-NCAR (National Centers for Environmental Prediction-National Center for Atmospheric Research) global reanalysis. One used the late 1995 operational Eta Model physics, the second, with a new soil and land surface scheme and revisions to the surface layer and boundary layer schemes, used the physics package that became operational on 31 January 1996. Improvements in the land surface parameterization and its interaction with the atmosphere are one key to improved summer precipitation forecasts. The new soil thermal model is an improvement over the earlier slab soil model, although the new skin temperature generally now has too large a diurnal cycle (whereas the old surface temperature had too small a diurnal cycle) and is more sensitive to net radiation errors. The nighttime temperature minima are often too low, because of a model underestimate of the downwelling radiation, despite improvements in the coupling of the surface and boundary layer at night, The daytime incoming solar radiation has a substantial high bias in both models, because of some coding errors (which have now been corrected), insufficient atmospheric shortwave absorption, and underestimates of cloud. The authors explore evaporation before and after a midsummer heavy rain event with the two models. The late 1995 operational model uses a soil moisture bucket physics, with a specified annual-mean fixed field soil moisture climatology, so the surface evaporation responds primarily to the atmospheric forcing. While the surface fluxes in the new model show this strong rain event more dramatically, because its soil moisture comes from the global reanalysis rather than climatology, there remain problems with soil moisture initialization. It appears that a fully continuous Eta data assimilation system (which is under development), likely with more than two soil layers and assimilation of observed hourly precipitation, will be needed to get an adequate soil moisture initialization. Evaporation in the new two-layer soil model falls too much from forecast day 1 to day 2, as the first shallow 10-cm layer dries out (as it also does in the 1995 model with the bucket physics). This appears to be related to the specified low vegetation fraction and the bare soil evaporation model. Although the new boundary layer scheme is better coupled to the surface at night, both versions underestimate entrainment at the top of the mixed layer. The improvement in the surface evaporation resulting from using a climatological green vegetation fraction (derived from satellite data) and a revised bare soil evaporation formulation are shown. These changes were incorporated in a model physics revision in February 1997. An encouraging result from one case study, when it rained in the model, shows that the interaction between the surface, boundary layer, and convection schemes during precipitation is satisfactory, although the model underestimates the impact of cloud cover on the incoming solar radiation. C1 NCEP,EMC,WASHINGTON,DC. RI Chen, Fei/B-1747-2009 NR 57 TC 145 Z9 152 U1 1 U2 5 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 NOV PY 1997 VL 125 IS 11 BP 2896 EP 2916 DI 10.1175/1520-0493(1997)125<2896:AOTLSA>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YE253 UT WOS:A1997YE25300009 ER PT J AU Anderson, JL AF Anderson, JL TI The impact of dynamical constraints on the selection of initial conditions for ensemble predictions: Low-order perfect model results SO MONTHLY WEATHER REVIEW LA English DT Article ID FORECAST SKILL; PERTURBATIONS; ADJOINT; SENSITIVITY; CIRCULATION; EVOLUTION; ERRORS; SYSTEM; NMC AB A number of operational atmospheric prediction centers now produce ensemble forecasts of the atmosphere. Because of the high-dimensional phase spaces associated with operational forecast models, many centers use constraints derived from the dynamics of the forecast model to define a greatly reduced subspace from which ensemble initial conditions are chosen. For instance, the European Centre for Medium-Range Weather Forecasts uses singular vectors of the forecast model and the National Centers for Environmental Prediction use the ''breeding cycle'' to determine a limited set of directions in phase space that are sampled by the ensemble forecast. The use of dynamical constraints on the selection of initial conditions for ensemble forecasts is examined in a perfect model study using a pair of three-variable dynamical systems and a prescribed observational error distribution. For these systems, one can establish that the direct use of dynamical constraints has no impact on the error of the ensemble mean forecast and a negative impact on forecasts of higher-moment quantities such as forecast spread. Simple examples are presented to show that this is not a result of the use of low-order dynamical systems but is instead related to the fundamental nature of the dynamics of these particular low-order systems themselves. Unless operational prediction models have fundamentally different dynamics, this study suggests that the use of dynamically constrained ensembles may not be justified. Further studies with more realistic prediction models are needed to evaluate this possibility. RP Anderson, JL (reprint author), PRINCETON UNIV,GEOPHYS FLUID DYNAM LAB,POB 308,PRINCETON,NJ 08540, USA. NR 45 TC 51 Z9 55 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 NOV PY 1997 VL 125 IS 11 BP 2969 EP 2983 DI 10.1175/1520-0493(1997)125<2969:TIODCO>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YE253 UT WOS:A1997YE25300012 ER PT J AU Reeder, PL Peurrung, AJ Sunberg, DS Stoffels, JJ ChenMayer, HH Mildner, DFR Sharov, VA Fokin, VS AF Reeder, PL Peurrung, AJ Sunberg, DS Stoffels, JJ ChenMayer, HH Mildner, DFR Sharov, VA Fokin, VS TI Metal capillaries for neutron lenses SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID CYLINDRICAL GUIDE TUBE; TRANSMISSION AB The use of metal reflective surfaces should greatly improve the transmission of neutron focusing devices based on glass polycapillary lenses because the longer scattering lengths of many metals allow greater critical angles compared to glass, The neutron transmission of single channel metal capillaries has been studied using cold neutron beams and an imaging neutron detector. Metal capillaries obtained from commercial sources have been studied both as supplied and as treated by chemical flow or electropolishing techniques to compare the transmission performance as a function of the smoothness of the metal surface. The reflectivities calculated from the experimental transmissions vary as a function of internal diameter and of capillary length, but are not sensitive to the various surface treatments studied here. None of the metal capillaries have reflectivities as good as the glass capillaries currently being used. C1 NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. XRAY OPT SYST INC, ALBANY, NY 12205 USA. RUSSIAN ACAD SCI, INST PHYS & TECHNOL, MOSCOW 117218, RUSSIA. RP Reeder, PL (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 10 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD NOV 1 PY 1997 VL 399 IS 1 BP 101 EP 112 DI 10.1016/S0168-9002(97)00903-0 PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA YE125 UT WOS:A1997YE12500013 ER PT J AU Rice, JP Zong, YQ Dummer, DJ AF Rice, JP Zong, YQ Dummer, DJ TI Spatial uniformity comparison of two nonimaging concentrators SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Annual Symposium on Infrared Radiometric Sensor Calibration CY MAY 13-15, 1997 CL UTAH STATE UNIV, LOGAN, UT SP Space Dynam Lab, Utah State Univ, NIST HO UTAH STATE UNIV DE infrared radiometric sensor calibration; concentrator; nonimaging; optics; radiometer; radiometry AB The spatial uniformity of two nonimaging concentrators is measured, each with a silicon photodetector positioned immediately behind the concentrator. The comparison is made between a compound parabolic concentrator (CPC) and a theta(i)/theta(o) concentrator. The latter consists of a parabolic section followed by a cone section to restrict the divergence angle of the exit beam. The spatial uniformity of the theta(i)/theta(o) concentrator measured with an f/4 beam diverging from a circular aperture is 1.2% across the central 4 mm of the entrance aperture of the concentrator, and demonstrates the use of this type of concentrator for effectively maintaining high throughput when using small-area (<2-mm-diam) detectors in applications requiring small fields of view. The uniformity of the gold-coated theta(i)/theta(o) concentrator measured with a nearly collimated HeNe laser beam is not nearly as good, due in part to the imperfect reflectance of gold. The uniformity of the CPC in the f/4 beam is not nearly as good as that of the theta(j)/theta(o) concentrator in the f/4 beam. (C) 1997 Society of Photo-Optical Instrumentation Engineers. RP Rice, JP (reprint author), NATL INST STAND & TECHNOL,OPT TECHNOL DIV,GAITHERSBURG,MD 20899, USA. NR 4 TC 6 Z9 6 U1 0 U2 4 PU SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD NOV PY 1997 VL 36 IS 11 BP 2943 EP 2947 DI 10.1117/1.601534 PG 5 WC Optics SC Optics GA YF405 UT WOS:A1997YF40500003 ER PT J AU Wallbank, B Djuric, N Woitke, O Zhou, S Dunn, GH Smith, ACH Bannister, ME AF Wallbank, B Djuric, N Woitke, O Zhou, S Dunn, GH Smith, ACH Bannister, ME TI Absolute cross sections for near-threshold electron-impact excitation of the 3s(2) S-1->3s3p P-1 and 3s(2) S-1->3s3p P-3 transitions in Si2+ SO PHYSICAL REVIEW A LA English DT Article ID ION EXCITATION; IONIZATION; SI-2+ AB Absolute total cross sections for electron-impact excitation of the 3s(2) S-1-->3s3p P-3 and 3s(2) S-1-->3s3p P-1 transitions in Si2+ were measured using the merged electron-ion beams energy-loss technique. The results are compared to R-matrix close-coupling theory, which predicts a strong resonance enhancement of the cross section near the threshold for excitation of the P-3 state and this is confirmed by the experiments. The observed disagreement between theory and experiment for the dipole excitation is suggested to be due to resonance interference. [S1050-2947(97)05911-8]. C1 NATL INST STAND & TECHNOL, BOULDER, CO 80309 USA. UCL, LONDON WC1E 6BT, ENGLAND. OAK RIDGE NATL LAB, DIV PHYS, OAK RIDGE, TN 37831 USA. ST FRANCIS XAVIER UNIV, DEPT PHYS, ANTIGONISH, NS B2G 2W5, CANADA. RP Wallbank, B (reprint author), UNIV COLORADO, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. NR 17 TC 21 Z9 22 U1 0 U2 1 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 NOV PY 1997 VL 56 IS 5 BP 3714 EP 3718 DI 10.1103/PhysRevA.56.3714 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA YF529 UT WOS:A1997YF52900051 ER PT J AU Schwabedissen, A Benck, EC Roberts, JR AF Schwabedissen, A Benck, EC Roberts, JR TI Influence of different coil geometries on the spatial distribution of the plasma density in planar inductively coupled plasmas SO PHYSICAL REVIEW E LA English DT Article ID ENERGY-DISTRIBUTIONS; POWER DEPOSITION; ETCHING REACTORS; REFERENCE CELL; MODEL; DISCHARGE; FLUXES AB The radial distributions of the electron density and the relative atomic argon excited state density have been investigated by means of Langmuir probes and optical emission spectroscopy, respectively, in planar inductively coupled plasmas. The plasma source is a modified Gaseous Electronics Conference RF Reference Cell [P. J. Hargis et nl., Rev. Sci. Instrum. 65, 140 (1994)]. Two different planar coil geometries, a five-turn spiral coil and a one-turn circular coil, were investigated for a variety of plasma parameters. Additionally, we investigated the effect of different powering configurations of the spiral coil and an electrostatic shield between the coil and the plasma. We found that the coil geometry and power configuration of the coil influences the radial distribution of the electron density in the region close to the coil only, while in the region close to the lower electrode the radial distribution is dominated by diffusion. RP Schwabedissen, A (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 44 TC 7 Z9 7 U1 1 U2 8 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 NOV PY 1997 VL 56 IS 5 BP 5866 EP 5875 DI 10.1103/PhysRevE.56.5866 PN B PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA YH168 UT WOS:A1997YH16800034 ER PT J AU Petrovic, ZL Phelps, AV AF Petrovic, ZL Phelps, AV TI Temporal and constriction behavior of low-pressure, cathode-dominated argon discharges SO PHYSICAL REVIEW E LA English DT Article ID CURRENT ELECTRICAL DISCHARGES; PARALLEL-PLANE ELECTRODES; CURRENT GLOW-DISCHARGE; GAS-DENSITY RATIOS; CROSS-SECTIONS; IONS; OSCILLATIONS; EXCITATION; FIELD; ATOMS AB Measurements of quasi-steady-state voltage-current characteristics, low-current voltage and current oscillations, and constriction formation are reported for cathode-dominated discharges in low-pressure Ar. Pulsed a discharges (similar to 5 ms long at 1-3 Hz) reduce heating and improve the accuracy of differential voltage measurements. Values of pressure p times the separation d of the parallel-plane electrodes are 0.12 to 2 Torr cm corresponding to discharge breakdown voltages of 2 kV to 230 V. Discharge currents range from 2 mu A to 40 mA. The quasi-steady-state discharge voltages decrease from their breakdown values in direct proportion to the current, i.e., the negative-differential-voltage-to-current ratio is constant. At currents below the onset of self-sustained sustained oscillations and at the higher pressures, the frequency and damping of transient oscillations are in agreement with a perturbation model based on changes in ion-induced electron emission at the cathode caused by space-charge electric fields. At the higher currents and low pressures transient voltage and current waveforms show the growth of low-frequency oscillations accompanying the onset of constrictions. Rotation of the constricted discharge is observed at these pressures. At the higher pressures the constrictions are stable during the pulse and emission scans parallel to the electrodes provide quantitative data on constricted discharge areas and emissivity per unit current as the discharge increases in size with increasing current. Comparisons are made of these experiments with recent models where possible. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80309. INST PHYS,YU-11001 BELGRADE,YUGOSLAVIA. RP Petrovic, ZL (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 67 TC 41 Z9 41 U1 0 U2 7 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 NOV PY 1997 VL 56 IS 5 BP 5920 EP 5931 DI 10.1103/PhysRevE.56.5920 PN B PG 12 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA YH168 UT WOS:A1997YH16800039 ER PT J AU Terashima, N Atalla, RH Vanderhart, DL AF Terashima, N Atalla, RH Vanderhart, DL TI Solid state NMR spectroscopy of specifically C-13-enriched lignin in wheat straw from coniferin SO PHYTOCHEMISTRY LA English DT Article DE Triticum aestivum; wheat; Gramineae; C-13-enrichment; solid state C-13 NMR spectroscopy; coniferin; lignin; lignin structure; interunit linkages ID NUCLEAR-MAGNETIC-RESONANCE; SIDE-CHAIN CARBONS; SELECTIVE C-13 ENRICHMENT; MILLED WOOD LIGNIN; DEFINED MORPHOLOGICAL PARTS; CELL-WALL LIGNIFICATION; STRUCTURAL CHARACTERIZATION; RADIOTRACER METHOD; BETA-GLUCOSIDASE; POLYMER MODELS AB Three coniferins, specifically C-13-enriched at side chain alpha, beta and gamma carbons, and natural abundance (unenriched) coniferin were administered to internode cavities of lignifying culms of dwarf wheat. Difference C-13 CP/MAS spectra were obtained between the spectra of the coniferin-fed and the unfed wheat straws, or between the spectra of straws fed with enriched coniferin and unenriched coniferin. The difference spectra indicated that, although the feeding of coniferin increased the lignin content slightly, the normal lignification process was not affected seriously by feeding of the precursor. The lignin derived from the coniferin in the wheat stalk was specifically C-13-enriched at the positions corresponding to the fed precursors. It is estimated that of the total lignin associated with the bottom and top sections of the wheat straws, respectively, 15.4 +/- 2.0 and 9.5 +/- 2.5% of the lignin originated from the labelled coniferin. The percentages of the major dimeric substructures of enriched lignin in the top and bottom of internodes, respectively, are: beta-O-4 including beta-O-4/alpha-O-R (R = carbohydrates and lignols), 74 +/- 1.5 and 65 +/- 1.5%; combined beta-5, beta-beta and B-I structures, 18 +/- 1.5 and 28 +/- 1.5%; and combined coniferyl alcohol and aldehyde end groups, 8 +/- 1.5 and 6 +/- 1.5%. (C) 1997 Elsevier Science Ltd. C1 NIST, DIV POLYMERS, GAITHERSBURG, MD 20899 USA. RP USDA, FOREST PROD LAB, MADISON, WI 53705 USA. NR 41 TC 33 Z9 33 U1 2 U2 21 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0031-9422 J9 PHYTOCHEMISTRY JI Phytochemistry PD NOV PY 1997 VL 46 IS 5 BP 863 EP 870 DI 10.1016/S0031-9422(97)00359-2 PG 8 WC Biochemistry & Molecular Biology; Plant Sciences SC Biochemistry & Molecular Biology; Plant Sciences GA YF763 UT WOS:A1997YF76300010 ER PT J AU El-Ahl, AAS Afeefy, H Metwally, MA AF El-Ahl, AAS Afeefy, H Metwally, MA TI Rapid entry to highly substituted 4,5-dihydronicotinonitriles SO REVUE ROUMAINE DE CHIMIE LA English DT Article ID AMMONIUM ACETATE; SALICYLALDEHYDE; KETONES AB Various 5-substituted 2-amino-3-cyano-4-(2-hydroxyphenyl)-4,5-dihydronicotinonitriles were prepared by ternary condensation of salicylaldehydes, malononitriles and aromatic heterocyclic ketones or by the condensation of 2-imino-3-cyanocoumarin and compounds with an active methylene in presence of ammonium acetate. The structures of these compounds were established by analytical and spectral analysis. C1 Mansoura Univ, Fac Sci, Dept Chem, Mansoura, Egypt. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP El-Ahl, AAS (reprint author), Mansoura Univ, Fac Sci, Dept Chem, Mansoura, Egypt. NR 10 TC 1 Z9 1 U1 0 U2 0 PU EDITURA ACADEMIEI ROMANE PI BUCHAREST PA CALEA VICTORIEI 125, BUCHAREST 79717, ROMANIA SN 0035-3930 J9 REV ROUM CHIM JI Rev. Roum. Chim. PD NOV PY 1997 VL 42 IS 11 BP 1049 EP 1053 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA ZH207 UT WOS:000073083600005 ER PT J AU Miller, HL Weaver, A Sanders, RW Arpag, K Solomon, S AF Miller, HL Weaver, A Sanders, RW Arpag, K Solomon, S TI Measurements of arctic sunrise surface ozone depletion events at Kangerlussuaq, Greenland (67 degrees N, to 51 degrees W) SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT European-Geophysical-Society Symposium on Arctic Tropospheric Chemistry CY MAY 06-10, 1996 CL THE HAGUE, NETHERLANDS SP European Geophys Soc ID NEAR-ULTRAVIOLET SPECTROSCOPY; MCMURDO-STATION; BOUNDARY-LAYER; POLAR SUNRISE; VISIBLE SPECTROSCOPY; TROPOSPHERIC OZONE; BROMINE; ANTARCTICA; RELEASE; OCLO AB In situ measurements of surface ozone were conducted from 30 January through 22 May 1995, at the Sondrestrom Incoherent Scatter Radar Facility near Kangerlussuaq, Greenland. Several periods of depleted ozone were observed, representing the lowest latitude measurements of springtime surface polar ozone depletion in the northern hemisphere to date. The most severe ozone depletion occurred during 14-17 March, when surface ozone levels abruptly fell to below 10 ppbv from typical values of about 40 ppbv. Simultaneous near-ultraviolet and visible total column spectroscopic measurements were made with ground-based instruments, yielding total column values for BrO and OClO. Elevated levels of BrO were observed at the onset of ozone depletion episodes and the behavior of BrO slant column values through the morning twilight of 15 March indicated that the BrO column must reside in the boundary layer. The boundary layer BrO mixing ratio was estimated at greater than 13 pptv during this episode. OClO levels showed no correlation with surface ozone depletion nor clear evidence of a large tropospheric burden. C1 UNIV COLORADO,CIRES,BOULDER,CO 80309. RP Miller, HL (reprint author), NOAA,AERON LAB,325 BROADWAY,REAL 8,BOULDER,CO 80303, USA. RI Miller, Henry/D-7628-2013 OI Miller, Henry/0000-0002-7155-8314 NR 32 TC 26 Z9 26 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD NOV PY 1997 VL 49 IS 5 BP 496 EP 509 DI 10.1034/j.1600-0889.49.issue5.6.x PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YJ577 UT WOS:A1997YJ57700006 ER PT J AU Robertson, BA Cannon, AC AF Robertson, BA Cannon, AC TI Occurrence of infectious bacteria in captive-reared Kemp's ridley (Lepidochelys kempii) and loggerhead (Caretta caretta) sea turtles SO TEXAS JOURNAL OF SCIENCE LA English DT Article AB Specimens of Kemp's ridley and loggerhead sea turtles which died during captive rearing (1984 to 1996) were subjected to complete necropsy. Seven different bacterial strains were isolated and identified from Kemp's ridleys and three strains from loggerheads. Salmonella spp., Aeromonas spp. and Pseudomonas spp. were found in both species. C1 NMFS, SE Fisheries Sci Ctr, Galveston Lab, Galveston, TX 77551 USA. RP Robertson, BA (reprint author), NMFS, SE Fisheries Sci Ctr, Galveston Lab, 4700 Ave U, Galveston, TX 77551 USA. NR 8 TC 1 Z9 2 U1 0 U2 1 PU TEXAS ACAD SCI PI LUBBOCK PA BOX 43151, LUBBOCK, TX 79409-3151 USA SN 0040-4403 J9 TEX J SCI JI Tex. J. Sci. PD NOV PY 1997 VL 49 IS 4 BP 331 EP 334 PG 4 WC Ecology; Zoology SC Environmental Sciences & Ecology; Zoology GA YN637 UT WOS:000071190400007 ER PT J AU Richards, RA Esteves, C AF Richards, RA Esteves, C TI Stock-specific variation in scale morphology of Atlantic striped bass SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID SHAPE-ANALYSIS; MORONE-SAXATILIS; DISCRIMINATION; SALMON; SIZE AB We examined scales of wild striped bass Morone saxatilis to determine whether scale morphology differs systematically among three Atlantic coast stocks and thus could be used for stock discrimination. Morphological variables investigated included Fourier coefficients, ratio shape descriptors (circularity, rectangularity), truss networks, perimeter landmarks, width and spacing of the first 10 circuli, and angular measurements of the scale interior, A variable was considered potentially useful for stock identification if it could be corrected for size variation, did not show year-class effects, and showed significant stock-of-origin effects in a multivariate analysis of variance. Fourier shape descriptors, rectangularity, and angular measurements of the scale interior showed the greatest potential for discrimination of Atlantic striped bass stocks. In addition, circulus patterns showed some usefulness. The remainder of the morphometric variables appeared less useful either because of failure to meet statistical assumptions for size correction (truss networks and perimeter landmarks), significant year-class effects (circulus patterns), or a paucity of significant stock-of-origin effects (truss networks, circulus patterns, circularity). Relatively few strong correlations (r greater than or equal to 0.70) were evident among morphological variables of different types. C1 Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Richards, RA (reprint author), Univ Maryland, Chesapeake Biol Lab, POB 38, Solomons, MD 20688 USA. NR 33 TC 10 Z9 15 U1 1 U2 4 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 0002-8487 EI 1548-8659 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD NOV PY 1997 VL 126 IS 6 BP 908 EP 918 DI 10.1577/1548-8659(1997)126<0908:SSVISM>2.3.CO;2 PG 11 WC Fisheries SC Fisheries GA ZB623 UT WOS:000072491100003 ER PT J AU Richards, RA Esteves, C AF Richards, RA Esteves, C TI Use of scale morphology for discriminating wild stocks of Atlantic striped bass SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID MORONE-SAXATILIS; GROWTH; SHAPE AB We used scale morphology to discriminate wild Atlantic striped bass Morone saxatilis from the Hudson River, Chesapeake Bay, and the Roanoke River. Morphological features used were perimeter shape as described by Fourier analysis, rectangularity, width and spacing of the first 10 circuli, and patterns of partitioning of the scale interior. Performance of discriminant functions was evaluated by examining the percent correct classification of known-origin samples (precision) and the bias in resulting stock composition estimates (accuracy). Correct classification rates ranged from 57% to 84%, varying with the number of stocks and year-classes included. Lowest rates were for three stocks with multiple year-classes; highest rates were for single-year-class analysis of the most geographically distant stocks. Despite some poor classification rates, bias and variance in stock composition estimates were low in four of five discrimination problems, suggesting that corrections based on the classification matrix could be applied with some confidence to unknown samples. However, we used bootstrapping to evaluate bias stability; further evaluation of independent samples would be useful. C1 Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Richards, RA (reprint author), Univ Maryland, Chesapeake Biol Lab, POB 38, Solomons, MD 20688 USA. NR 41 TC 16 Z9 20 U1 2 U2 3 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 0002-8487 EI 1548-8659 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD NOV PY 1997 VL 126 IS 6 BP 919 EP 925 DI 10.1577/1548-8659(1997)126<0919:UOSMFD>2.3.CO;2 PG 7 WC Fisheries SC Fisheries GA ZB623 UT WOS:000072491100004 ER PT J AU Chou, YK Evans, CJ AF Chou, YK Evans, CJ TI Tool wear mechanism in continuous cutting of hardened tool steels SO WEAR LA English DT Article DE cubic boron nitride (CBN) tools; hard turning; tool wear; tool steels; carbide sizes AB Precision hard turning provides an alternative to grinding in some finishing applications. Rapid tool wear, however, remains an impediment to the process being economically viable. This experimental study investigates microstructural aspects of cubic boron nitride (CBN) tool wear in finish hard turning. Results indicate the followig: (1) carbide sizes of the workpiece have significant effects on tool wear; (2) the flank wear rate can be correlated with mean carbide diameter of the workpiece; (3) the wear resistance increases monotonically with decreasing CBN grain size: (4) in finish turning with low CBN content tools, the governing wear mechanism is fine scale attrition by microfracture and fatigue. A powder metallurgy M50 bar hard turned using an ultrafine CBN grain tool shows flank wear less than 45 mu m VBmax after 6.2 km cutting distance; this wear rate equals 3.1 mu m/km, over an order of magnitude lower than when machining conventional M50 under identical conditions. The surface finish is better than 80 nm R-a. (C) 1997 U.S. Government. Published by Elsevier Science S.A. C1 NIST, Gaithersburg, MD 20899 USA. RP Chou, YK (reprint author), NIST, B106 Sound Bldg, Gaithersburg, MD 20899 USA. NR 16 TC 74 Z9 75 U1 0 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD NOV PY 1997 VL 212 IS 1 BP 59 EP 65 DI 10.1016/S0043-1648(97)00139-7 PG 7 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA YM263 UT WOS:000071046100008 ER PT J AU Gessner, BD Middaugh, JP Doucette, GJ AF Gessner, BD Middaugh, JP Doucette, GJ TI Paralytic shellfish poisoning in Kodiak, Alaska SO WESTERN JOURNAL OF MEDICINE LA English DT Article ID FISH; STX C1 NATL MARINE FISHERIES SERV,US DEPT COMMERCE,NATL OCEAN & ATMOSPHER ADM,SE FISHERIES SCI CTR,CHARLESTON,SC. RP Gessner, BD (reprint author), ALASKA DIV PUBL HLTH,1231 GAMBELL ST,2ND FLOOR,ANCHORAGE,AK 99501, USA. RI Doucette, Gregory/M-3283-2013 NR 13 TC 5 Z9 5 U1 0 U2 3 PU CARDEN JENNINGS PUBL CO LTD PI CHARLOTTESVILLE PA BLAKE CTR, STE 200, 1224 W MAIN ST, CHARLOTTESVILLE, VA 22903 SN 0093-0415 J9 WESTERN J MED JI West. J. Med. PD NOV PY 1997 VL 167 IS 5 BP 351 EP 353 PG 3 WC Medicine, General & Internal SC General & Internal Medicine GA YG385 UT WOS:A1997YG38500014 PM 9392992 ER PT J AU Pella, PA Lankosz, M AF Pella, PA Lankosz, M TI Highlights of X-ray spectrometry for microanalysis SO X-RAY SPECTROMETRY LA English DT Article ID MICROFLUORESCENCE ANALYSIS; FLUORESCENCE; OPTICS AB A review of selected highlights of x-ray fluorescence spectrometry applied to the analysis of micro-samples and/or for localized area analysis is presented from a historical perspective. A look towards the future indicates broader commercialization of laboratory instrumentation for microanalysis and compositional mapping due to important advances in capillary x-ray optics. (C) 1997 John Wiley & Sons, Ltd. C1 KRAKOW TECH UNIV, FAC PHYS & NUCL TECH, KRAKOW, POLAND. RP Pella, PA (reprint author), NIST, BLDG 222, ROOM B-224, GAITHERSBURG, MD 20899 USA. NR 48 TC 10 Z9 10 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0049-8246 J9 X-RAY SPECTROM JI X-Ray Spectrom. PD NOV-DEC PY 1997 VL 26 IS 6 BP 327 EP 332 PG 6 WC Spectroscopy SC Spectroscopy GA YG793 UT WOS:A1997YG79300004 ER PT J AU Lankosz, M Pella, PA AF Lankosz, M Pella, PA TI A new approach to quantitative X-ray microfluorescence analysis of individual particles SO X-RAY SPECTROMETRY LA English DT Article AB In the x-ray microfluorescence analysis of particles, the characteristic line intensity depends not only on the chemical composition of the sample, but also on the x-ray beam profile, particle size, shape and orientation, In previous work, optical measurements of particle dimensions were required to develop parametric equations for correction of both particle size and interelement effects, In that work the measurement of particle dimensions was limited in accuracy by the optical system used, A different approach here is described in which an estimate of the size of an irregularly shaped particle is obtained indirectly, This technique is particularly useful for the analysis of particles in which the concentrations of low atomic number elements are known or can be obtained from stoichiometry. This procedure has been tested with irregularly shaped, homogeneous glass particles of known composition and size ranging from 50-150 mu m using an x-ray microbeam 177 mu m in diameter. (C) 1997 John Wiley & Sons, Ltd. C1 NIST,GAITHERSBURG,MD 20899. RP Lankosz, M (reprint author), KRAKOW TECH UNIV,FAC PHYS & NUCL TECH,AL MICKIEWICZA 30,PL-30059 KRAKOW,POLAND. NR 4 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 0049-8246 J9 X-RAY SPECTROM JI X-Ray Spectrom. PD NOV-DEC PY 1997 VL 26 IS 6 BP 347 EP 349 PG 3 WC Spectroscopy SC Spectroscopy GA YG793 UT WOS:A1997YG79300006 ER PT J AU Scott, JF Ledbetter, H AF Scott, JF Ledbetter, H TI Interpretation of elastic anomalies in SrTiO3 at 37 K SO ZEITSCHRIFT FUR PHYSIK B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT Euroconference on Electron-Phonon-Interactions and Phase Transitions in Honor of Professor Heinz Bilz CY JUN 09-15, 1997 CL ERICE, ITALY SP Int Sch Solid State Phys ID QUANTUM PARAELECTRIC REGIME; PHONONS; PHASE AB We relate the measurements by Ming Lei and Hassel Ledbetter (1991) of elastic moduli in strontium titanate near 37 K to a dynamical anharmonic mode coupling model. It is suggested that the effects are purely dynamic and not indicative of a true structural phase transition and that neither macroscopic coherence nor second sound is involved. C1 Max Planck Inst Microstruct Phys, D-06120 Halle, Germany. Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. RP Scott, JF (reprint author), Max Planck Inst Microstruct Phys, D-06120 Halle, Germany. NR 29 TC 41 Z9 41 U1 0 U2 6 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0722-3277 J9 Z PHYS B CON MAT JI Z. Phys. B-Condens. Mat. PD NOV PY 1997 VL 104 IS 4 BP 635 EP 639 DI 10.1007/s002570050500 PG 5 WC Physics, Condensed Matter SC Physics GA YM561 UT WOS:000071077100008 ER PT J AU Delaney, N Faeder, J Maslen, PE Parson, R AF Delaney, N Faeder, J Maslen, PE Parson, R TI Photodissociation, recombination, and electron transfer in cluster ions: A nonadiabatic molecular dynamics study of I-2(-)(CO2)(n) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Letter ID VIBRATIONAL-RELAXATION; ULTRAFAST PHOTODISSOCIATION; CHARGE FLOW; I2; I-2(-); TRANSITIONS; ETHANOL AB we simulate and interpret the photodissociation and recombination of I-2(-) embedded in CO2 clusters using a Hamiltonian that accounts for the strong perturbation of the solute electronic structure by the solvent. The calculated product distributions agree well with the experimental results of Lineberger and co-workers. Excited-state dynamics are more involved than anticipated from the isolated solute potential curves. For example, dissociation does not occur from the A' state, and permanent recombination occurs only on the X state, despite the fact that the A state of I-2(-) is weakly bound. we discuss the role of the cluster environment in bringing about recombination and electronic relaxation in terms of a qualitative model inspired by the theory of electron transfer in solution. C1 UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. NR 29 TC 36 Z9 36 U1 0 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 OCT 30 PY 1997 VL 101 IS 44 BP 8147 EP 8151 DI 10.1021/jp972435n PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YE041 UT WOS:A1997YE04100001 ER PT J AU Schirripa, MJ Goodyear, CP AF Schirripa, MJ Goodyear, CP TI Simulation of alternative assumptions of fish otolith-somatic growth with a bioenergetics model SO ECOLOGICAL MODELLING LA English DT Article DE fish; otolith growth; somatic growth; bioenergetics ID BASS MORONE-SAXATILIS; ATLANTIC SALMON PARR; STRIPED BASS; CHESAPEAKE BAY; SALAR L; RIVER; FIELD; RATES AB Three different assumptions of the otolith-somatic growth relation were simulated using an individual-based bioenergetics model. The LINEAR model assumed that otolith growth was directly related to somatic growth; the TEMP-WT assumed that otolith growth was a function of ambient temperature and the weight of the fish; and the O2CON model assumed that otolith growth was a function of oxygen consumption. Although the LINEAR model resulted in an otolith radius-total length relation most often observed in nature (linear), otolith growth in the model ceased at temperatures and food rations that curtailed somatic growth, which contradicts some other studies. Model otolith growth continued at temperatures and ration levels that curtailed somatic growth in the TEMP-WT and O2CON model, however the resulting otolith radius-total length relation from the O2CON model was not as similar to naturally occurring ones. In all three models slower growing fish had larger otoliths than did faster growing fish of the same size when somatic growth was food limited. However, in the TEMP-WT and O2CON models, faster growing fish had larger otoliths when growth was limited by temperature. Different geometries between the fish body and otolith resulted in different growth rates between the two structures in terms of length, despite the fact that their growth rates in terms of weight were identical. This implies that a comparison between somatic and otolith growth needs to consider and specify the dimensions involved. (C) 1997 Elsevier Science B.V. C1 NATL MARINE FISHERIES SERV, SW FISHERIES SCI CTR, MIAMI LAB, MIAMI, FL USA. RP Schirripa, MJ (reprint author), FLORIDA INT UNIV, DEPT BIOL, UNIV PK, MIAMI, FL 33199 USA. NR 30 TC 12 Z9 13 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 J9 ECOL MODEL JI Ecol. Model. PD OCT 29 PY 1997 VL 102 IS 2-3 BP 209 EP 223 DI 10.1016/S0304-3800(97)00057-4 PG 15 WC Ecology SC Environmental Sciences & Ecology GA YG562 UT WOS:A1997YG56200002 ER PT J AU Peskin, AP Ko, MK Pellegrino, JJ AF Peskin, AP Ko, MK Pellegrino, JJ TI Three layer membrane model for characterizing ultrafiltration membranes (vol 60, pg 195, 1991) SO JOURNAL OF MEMBRANE SCIENCE LA English DT Correction, Addition RP Peskin, AP (reprint author), NATL INST STAND & TECHNOL,CHEM ENGN SCI DIV,325 BROADWAY,BOULDER,CO 80303, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD OCT 29 PY 1997 VL 134 IS 2 BP 271 EP 271 PG 1 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA YC934 UT WOS:A1997YC93400015 ER PT J AU MeotNer, M Sieck, LW Koretke, KK Deakyne, CA AF MeotNer, M Sieck, LW Koretke, KK Deakyne, CA TI The carbon lone pair as electron donor. Ionic hydrogen bonds in isocyanides SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GAUSSIAN-BASIS SETS; GAS-PHASE ION; PROTON AFFINITIES; INTERMOLECULAR INTERACTIONS; MOLECULAR CALCULATIONS; ROTATIONAL SPECTRUM; METHYL ISOCYANIDE; ONIUM IONS; COMPLEXES; NH3 AB Hydrogen bond dissociation energies (Delta H degrees(D)) in protonated dimer ions containing isocyanides were measured by pulsed high-pressure mass spectrometry, and the interactions were analyzed by ab initio calculations. Strong bonding (80-105 kT/mol (19-25 kcal/mol)) is observed when the carbon lone pair is the electron donor, i.e. in the complexes of isocyanides with protonated amines and protonated isocyanides (R3NH+...CNR and RNCH+...CNR complexes). The bonding is weaker (60-90 kT/mol (14-21 kcal/mol)) in the complexes of oxygen bases with protonated isocyanides, i.e, in RNCH+...O-type complexes. Inverse linear correlations between Delta H degrees(D) and the proton affinity difference of the components show slopes of -0.22 for R3NH+...CNR-and -0.25 for RNCH+...O-type complexes. The intercepts yield intrinsic bond strengths (Delta PA = 0) of 107.7 (25.7 kcal/mol) and 100.0 kJ/mol (23.9 kcal/mol), respectively. Geometry optimizations were carried out at four calculational levels, the largest of which is MP2/6-31+G(d,p). Single-point energies were obtained with increasingly flexible basis sets up to cc-pVTZ+. Trends in dissociation energies within the cyanide and isocyanide series of complexes and between the two series of complexes hold for every basis set considered. Calculated and experimental Delta H degrees(D) values agree within the standard uncertainty of +/-6 kJ/mol (1.5 kcal/mol) for only four of the nine complexes for which experimental data are available. The hydrogen bonding properties of sp-type carbon vs nitrogen lone pairs are illustrated by comparing analogous isocyanide and cyanide complexes. The relative importance of the electrostatic and delocalization components of the dissociation energy is different for the two sets of complexes, with delocalization effects being more important for the isocyanides. C1 NATL INST STAND & TECHNOL, CHEM KINET & THERMODYNAM DIV, GAITHERSBURG, MD 20876 USA. EASTERN ILLINOIS UNIV, DEPT CHEM, CHARLESTON, IL 61920 USA. NR 71 TC 19 Z9 19 U1 0 U2 0 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 OCT 29 PY 1997 VL 119 IS 43 BP 10430 EP 10438 DI 10.1021/ja960669z PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA YD815 UT WOS:A1997YD81500020 ER PT J AU Casey, RN Quackenbush, SL Work, TM Balazs, GH Bowser, PR Casey, JW AF Casey, RN Quackenbush, SL Work, TM Balazs, GH Bowser, PR Casey, JW TI Evidence for retrovirus infections in green turtles Chelonia mydas from the Hawaiian islands SO DISEASES OF AQUATIC ORGANISMS LA English DT Article DE green turtle; reverse transcriptase; retrovirus; fibropapillomatosis; electron microscopy ID CUTANEOUS FIBROPAPILLOMAS; STIZOSTEDION-VITREUM; TUMOR; VIRUS; PARTICLES; WALLEYE; FISH AB Apparently normal Hawaiian green turtles Chelonia mydas and those displaying fibropapillomas were analyzed for infection by retroviruses. Strikingly, all samples were positive for polymerase enhanced reverse transcriptase (PERT) with levels high enough to quantitate by the conventional reverse transcriptase (RT) assay. However, samples of skin, even from asymptomatic turtles, were RT positive, although the levels of enzyme activity in healthy turtles hatched and raised in captivity were much lower than those observed in asymptomatic free-ranging turtles. Turtles with fibropapillomas displayed a broad range of reverse transcriptase activity. Skin and eye fibropapillomas and a heart tumor were further analyzed and shown to have reverse transcriptase activity that banded in a sucrose gradient at 1.17 g ml(-1). The reverse transcriptase activity purified from the heart tumor displayed a temperature optimum of 37 degrees C and showed a preference for Mn2+ over Mg2+. Sucrose gradient fractions of this sample displaying elevated reverse transcriptase activity contained primarily retroviral-sized particles with prominent envelope spikes, when negatively stained and examined by electron microscopy. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of gradient-purified virions revealed a conserved profile among 4 independent tumors and showed 7 prominent proteins having molecular weights of 116, 83, 51, 43, 40, 20 and 14 kDa. The data suggest that retroviral infections are widespread in Hawaiian green turtles and a comprehensive investigation is warranted to address the possibility that these agents cause green turtle fibropapillomatosis (GTFP). C1 CORNELL UNIV,COLL VET MED,DEPT MICROBIOL & IMMUNOL,ITHACA,NY 14853. US GEOL SURVEY,BIOL RESOURCES DIV,NATL WILDLIFE HLTH CTR,HONOLULU FIELD STN,HONOLULU,HI 96850. NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822. RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 NR 31 TC 31 Z9 34 U1 0 U2 0 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0177-5103 J9 DIS AQUAT ORGAN JI Dis. Aquat. Org. PD OCT 28 PY 1997 VL 31 IS 1 BP 1 EP 7 DI 10.3354/dao031001 PG 7 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA YK736 UT WOS:A1997YK73600001 ER PT J AU Senturker, S Karahalil, B Inal, M Yilmaz, H Muslumanoglu, H Gedikoglu, G Dizdaroglu, M AF Senturker, S Karahalil, B Inal, M Yilmaz, H Muslumanoglu, H Gedikoglu, G Dizdaroglu, M TI Oxidative DNA base damage and antioxidant enzyme levels in childhood acute lymphoblastic leukemia SO FEBS LETTERS LA English DT Article DE catalase; hydroxyl radical; modified base; oxidative DNA damage; oxygen-derived species ID HYDROGEN-PEROXIDE; DEOXYRIBONUCLEIC-ACID; MASS-SPECTROMETRY; FREE-RADICALS; HUMAN-CELLS; IN-VITRO; 8-HYDROXYGUANINE; MUTAGENESIS; SUPEROXIDE; CHROMATIN AB We have investigated the levels of several antioxidant enzymes and the level of oxidative DNA base damage in lymphocytes of children with acute lymphoblastic leukemia (ALL) and in disease-free children, Children with ALL had just been diagnosed,vith the disease and had received no therapy prior to obtaining blood samples, A multitude of typical hydroxyl radical-induced base lesions in lymphocyte DNA of children were identified and quantified by gas chromatography-isotope dilution mass spectrometry. Higher levels of DNA base lesions were observed in patients with ALL than in children without the disease, The levels of the antioxidant enzymes glutathione peroxidase, catalase and superoxide dismutase in lymphocytes of ALL patients were lower than in lymphocytes of controls, These findings are in agreement with earlier observations in various types of adulthood cancer, Some of the identified DNA base lesions are known to possess premutagenic properties and may play a role in carcinogenesis, The results may indicate a possible link between decreased activities of antioxidant enzymes and increased levels of DNA base lesions due to oxidative damage, and support the notion that free radical reactions may be increased in malignant cells. (C) 1997 Federation of European Biochemical Societies. C1 NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. OSMAN GAZI UNIV,FAC MED,DEPT BIOCHEM,ESKISEHIR,TURKEY. GAZI UNIV,FAC PHARM,DEPT TOXICOL,ANKARA,TURKEY. UNIV ISTANBUL,DEPT MOL MED,EXPT MED RES INST,ISTANBUL,TURKEY. OSMAN GAZI UNIV,FAC MED,DEPT GENET,ESKISEHIR,TURKEY. UNIV ISTANBUL,FAC MED,DEPT GENET,ISTANBUL,TURKEY. UNIV ISTANBUL,FAC MED,FDN OUR CHILDREN LEUKEMIA,ISTANBUL,TURKEY. NR 36 TC 71 Z9 72 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD OCT 27 PY 1997 VL 416 IS 3 BP 286 EP 290 DI 10.1016/S0014-5793(97)01226-X PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA YE704 UT WOS:A1997YE70400015 PM 9373171 ER PT J AU Dong, XQ Ackerman, TP Clothiaux, EE Pilewskie, P Han, Y AF Dong, XQ Ackerman, TP Clothiaux, EE Pilewskie, P Han, Y TI Microphysical and radiative properties of boundary layer stratiform clouds deduced from ground-based measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE STRATOCUMULUS CLOUDS; EXTENDED WATER CLOUDS; NOCTURNAL STRATOCUMULUS; SOLAR-RADIATION; MULTIPLE-SCATTERING; BUDGET EXPERIMENT; STRATUS CLOUD; DOPPLER RADAR; ASTEX; ABSORPTION AB Two methods for retrieving the microphysical and radiative properties of marine and continental boundary layer stratiform clouds from ground-based measurements are implemented. The first method uses measurements of the cloud liquid water path and the cloud nadir radiance at 1 mu m to infer the cloud optical depth, cloud droplet effective radius, and cloud droplet concentration. In the second method a delta 2-stream radiative transfer model is used to retrieve the microphysical and radiative properties of stratiform clouds from measurements of the cloud liquid water path, the cloud geometric thickness, the downward shortwave irradiance at the surface, and atmospheric profiles of temperature, pressure, and relative humidity. In all of the retrievals the cloud droplets are assumed to have a lognormal size distribution with a logarithmic width of 0.35; the cloud droplet modal radius and cloud droplet concentration are free parameters. Data obtained in the Azores and Oklahoma from marine and continental boundary layer stratiform clouds, respectively, are used in the study.-Results of the analysis demonstrated that the retrieved cloud droplet effective radii from the marine clouds (13 mu m) were generally larger than the values from continental clouds (7 mu m), while cloud droplet number concentrations were much less in marine clouds (150 cm(-3)) than in continental clouds (500 cm(-3)). The retrieved cloud droplet effective radius had a strong negative correlation with the cloud droplet concentration. The effects of uncertainties in the measurements, the cloud droplet distribution width, and the Surface albedo on the retrieved properties were evaluated by using the delta 2-stream model. The errors in the retrieved cloud radiative properties were generally less than 5%, while the errors in the retrieved cloud microphysical properties were considerably larger. C1 PENN STATE UNIV, DEPT METEOROL, UNIVERSITY PK, PA 16802 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80303 USA. NASA, AMES RES CTR, ATMOSPHER PHYS RES BRANCH, MOFFETT FIELD, CA 94035 USA. NOAA, ENVIRONM TECHNOL LAB, BOULDER, CO 80303 USA. RI Han, Yong/F-5590-2010; OI Han, Yong/0000-0002-0183-7270; Dong, Xiquan/0000-0002-3359-6117 NR 45 TC 65 Z9 67 U1 0 U2 7 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 OCT 27 PY 1997 VL 102 IS D20 BP 23829 EP 23843 DI 10.1029/97JD02119 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YD175 UT WOS:A1997YD17500006 ER PT J AU Buntin, SA AF Buntin, SA TI H atom abstraction of D adsorbed on Si(100): dynamical evidence for an Eley-Rideal mechanism SO CHEMICAL PHYSICS LETTERS LA English DT Article ID GAS-PHASE; STATE DISTRIBUTIONS; HYDROGEN ADSORPTION; SURFACE-CHEMISTRY; SI(111) SURFACES; D-2 ADSORPTION; DESORPTION; KINETICS; INCIDENT; SILICON AB Kinetic energy distributions are reported for the HD product from the reaction of incident gas phase H atoms with D adsorbed on Si(100). For an incident kinetic energy of nominally 1 eV, the HD product kinetic energy distribution extends up to the nominal available-energy limit and has a mean value of 1.2-1.3 eV, providing dynamic evidence for a direct Eley-Rideal mechanism. For higher incident Fl atom kinetic energies, the HD product kinetic energy distribution broadens while the mean value remains unchanged, suggesting that energy loss to the substrate becomes more significant and the reaction becomes less Eley-Rideal-like. (C) 1997 Elsevier Science B.V. RP Buntin, SA (reprint author), NIST,SURFACE & MICROANAL SCI DIV,GAITHERSBURG,MD 20899, USA. NR 32 TC 24 Z9 24 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD OCT 24 PY 1997 VL 278 IS 1-3 BP 71 EP 76 DI 10.1016/S0009-2614(97)01030-0 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YF643 UT WOS:A1997YF64300012 ER PT J AU Sieck, LW AF Sieck, LW TI Gas-phase proton affinity and protonation entropy scale between acetaldehyde and methyl acetate. An experimental evaluation and comparative analysis SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TEMPERATURE EQUILIBRIUM MEASUREMENTS; PRESSURE ION-SOURCE; VARIABLE-TEMPERATURE; THERMAL-DECOMPOSITION; ETHANOL; THERMOCHEMISTRY; REEVALUATION; ASSOCIATION; ISOBUTENE; MOLECULES AB The thermochemistry associated with the gas-phase proton affinity scale between acetaldehyde and methyl acetate has been reinvestigated by variable-temperature equilibrium measurements using pulsed electron beam high-pressure mass spectrometry. This experimentally difficult and sometimes kinetically inaccessible subset is particularly important since it provides the only bridge between the expansive lower and upper scales. Data were taken from 497 to 665 K, with an average temperature for all base pair combinations of 584 K. Special care was taken to ensure that the measurements accurately reflected both the Delta H degrees and Delta S degrees values within this temperature range. The present data indicate that earlier values from this laboratory within the same subset were expanded by similar to 13% in both Delta G degrees and Delta H degrees, although no evidence was found for a similar expansion in our original ladder for bases with proton affinities above isobutene, which was used as the reference base in that study. A detailed analysis and comparison between experimental and computational scales is presented, emphasizing both the Delta H degrees and Delta S degrees values associated with protonation. Significant differences in the thermochemistry are found to exist between the present data and the most recent experimental ladder within this important bridging region. RP NIST, PHYS & CHEM PROPERTIES DIV, GAITHERSBURG, MD 20899 USA. NR 25 TC 13 Z9 14 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD OCT 23 PY 1997 VL 101 IS 43 BP 8140 EP 8145 DI 10.1021/jp970959h PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YD603 UT WOS:A1997YD60300035 ER PT J AU Langer, SA Liu, AJ AF Langer, SA Liu, AJ TI Effect of random packing on stress relaxation in foam SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID COMPRESSED EMULSIONS; ELASTICITY AB Numerical simulations are conducted to examine the effect of randomness in the bubble packing on the local elastic properties of a foam. We find that the response to a small-amplitude strain is spatially inhomogeneous: there are regions (of several bubbles) where bubbles shift their positions in order to prevent distortion. These regions respond differently when sheared in different directions, showing that the regions are elastically anisotropic. This work verifies assumptions made in an earlier, coarse-grained model. C1 UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90095. NIST,MATH & COMPUTAT SCI DIV,GAITHERSBURG,MD 20899. NR 7 TC 41 Z9 41 U1 1 U2 6 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 OCT 23 PY 1997 VL 101 IS 43 BP 8667 EP 8671 DI 10.1021/jp971265b PG 5 WC Chemistry, Physical SC Chemistry GA YD604 UT WOS:A1997YD60400008 ER PT J AU Baglin, FG Sweitzer, S Friend, DG AF Baglin, FG Sweitzer, S Friend, DG TI Interaction induced Raman light scattering studies of CH4/H-2 mixtures as a function of density SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MOLECULES; FLUIDS; MODE AB We have recently interrogated several binary supracritical mixtures by means of interaction-induced Raman light scattering originating from a probe molecule (supracritical methane) at a concentration of 10 mol % in a variety of supracritical solvent systems (e.g., Ar, CO2, CF4, etc.). In this paper we look at a very different kind of solvent, supracritical molecular hydrogen. It was chosen because of its well-known reorientational properties, i.e., quantum mechanical rotation in all phases (except perhaps metallic H-2(s)). The results indicate that the I/d vs d plots are more complicated than earlier systems studied and give good evidence of additional numbers of H-2 molecules clustered around the solute CH4. Hydrogen's absolute differential Raman rotational cross-section for Delta J = 1 --> 3 is very well known and combined with the cross-section of the methane probe molecules' nu(1) symmetric stretching vibration, it was possible to quantify and compare the contributions of various mechanisms known to be present in interaction-induced Raman light scattering of a wide variety of solvents and to therefore judge their solvating capacities vis a vis CH4. C1 NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,BOULDER,CO 80303. RP Baglin, FG (reprint author), UNIV NEVADA,CHEM PHYS PROGRAM,RENO,NV 89557, USA. NR 20 TC 0 Z9 0 U1 1 U2 1 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 OCT 23 PY 1997 VL 101 IS 43 BP 8816 EP 8822 DI 10.1021/jp9630481 PG 7 WC Chemistry, Physical SC Chemistry GA YD604 UT WOS:A1997YD60400027 ER PT J AU Plusquellic, DF Votava, O Nesbitt, DJ AF Plusquellic, DF Votava, O Nesbitt, DJ TI Photodissociation dynamics of jet-cooled H2O and D2O in the non-Franck-Condon regime: Relative absorption cross sections and product state distributions at 193 nm SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACE; VIBRATIONALLY EXCITED WATER; RESOLVED PHOTODISSOCIATION; STRETCHING VIBRATIONS; SPECTROSCOPIC DATA; GROUND-STATE; TERM VALUES; A-STATE; OH; BAND AB Quantum state distributions for nascent OH and OD fragments generated by Franck-Condon ''forbidden'' 193 nm photodissociation of H2O and D2O are reported, with the two isotopomers initially prepared in their zero-point vibrational and lowest ortho/para nuclear spin allowed rotational states (i.e., J(KaKc)=1(01) and 0(00) in a 3:1 ratio for H2O and 1:2 ratio for D2O) by cooling in a slit supersonic expansion. Product state distributions are probed via OH/OD laser-induced fluorescence (LIF) with cylindrical mirror collection optics optimized for the slit expansion geometry, which makes photodissociation studies feasible with cross sections as low as approximate to 10(-26) cm(2). The OH and OD fragments are formed exclusively in v=0, but with highly structured quantum state distributions in rotational, Lambda-doublet, and fine structure levels ((II3/2+)-I-2, (II1/2+)-I-2, and (II3/2-)-I-2) that exhibit qualitatively different trends than observed in previous jet photolysis studies at 157 nm in the Franck-Condon ''allowed'' regime. The relative OH/OD fragment yields at 193 nm indicate a 64+/-10 times greater propensity for OH vs OD bond cleavage in H2O than D2O, which is more than three-fold smaller than predicted from full three-dimensional quantum scattering calculations on ground ((X) over tilde(1)A(1)) and first excited state ((A) over tilde(1)B(1)) potential surfaces. One-dimensional semiclassical calculations of the Franck-Condon overlap matrix elements confirm these discrepancies to be considerably outside uncertainties associated with the ground and excited state potential surfaces. These results indicate that the photodissociation dynamics for this benchmark system are not yet fully understood and suggest either non-Born-Oppenheimer effects or contributions from other electronic surfaces may be important in the extreme non-Franck-Condon photolysis regime. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. UNIV COLORADO,NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NR 75 TC 28 Z9 28 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 22 PY 1997 VL 107 IS 16 BP 6123 EP 6135 DI 10.1063/1.474280 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YB713 UT WOS:A1997YB71300014 ER PT J AU Lee, C Gido, SP Poulos, Y Hadjichristidis, N Tan, NB Trevino, SF Mays, JW AF Lee, C Gido, SP Poulos, Y Hadjichristidis, N Tan, NB Trevino, SF Mays, JW TI H-shaped double graft copolymers: Effect of molecular architecture on morphology SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID STAR BLOCK-COPOLYMERS; MICROPHASE SEPARATION; CONFORMATIONAL ASYMMETRY; DIBLOCK COPOLYMERS; EQUILIBRIUM; STYRENE; DOMAINS; POLYBUTADIENE; ISOPRENE AB The morphologies formed by block copolymers with a double-graft, H or S2IS2 architecture were investigated using transmission electron microscopy (TEM) and small angle neutron scattering (SANS). Here S and I represent blocks of polystyrene and polyisoprene, respectively. These materials were synthesized using anionic polymerization and chlorosilane Linking, and they were characterized using size exclusion chromatography, membrane osmometry, and low-angle laser light scattering. This characterization work confirmed the desired molecular architectures and narrow molecular weight distributions. The results of morphological characterization indicate that one can understand complex grafting architectures by decomposing them into fundamental building blocks, which are taken as the component single graft structures out of which the larger structure is constructed. We propose rules for dividing structures into these components, which we call constituting block copolymers. The morphological behavior of the more complex architecture is approximately equivalent to that of the constituting block copolymer structure. Through the use of the constituting block copolymers we map the experimentally determined morphological behavior of the H architecture onto the morphology diagram calculated by Milner for miktoarm stars [Macromolecules 27, 2333 (1994)]. Mapping the H architecture onto the morphology diagram in this way produces general agreement between experimental results and the model. However, it is found that in the case of the H architecture, as well as in previously published results for I2S and I3S miktoarm star materials, that the morphology diagram slightly overestimates the amount of shift in the order-order transition lines produced by asymmetry in molecular architecture. This overestimation in the theory is attribute to a junction point localization effect which was neglected in Milner's calculation. (C) 1997 American Institute of Physics. C1 UNIV MASSACHUSETTS,DEPT POLYMER SCI & ENGN,WM KECK ELECTRON MICROSCOPY LAB,AMHERST,MA 01003. INST ELECT STRUCT & LASER,IRAKLION 71110,CRETE,GREECE. UNIV ATHENS,DEPT CHEM,ATHENS 15771,GREECE. USA,RES LAB,POLYMERS RES BRANCH,ABERDEEN PROVING GROUND,MD 21005. NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. UNIV ALABAMA,DEPT CHEM,BIRMINGHAM,AL 35294. NR 35 TC 79 Z9 79 U1 1 U2 11 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 OCT 22 PY 1997 VL 107 IS 16 BP 6460 EP 6469 DI 10.1063/1.474266 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YB713 UT WOS:A1997YB71300047 ER PT J AU Waksman, R Abizaid, A Chan, RC Oljaca, B Soares, CG Mintz, GS AF Waksman, R Abizaid, A Chan, RC Oljaca, B Soares, CG Mintz, GS TI The importance of centering for intracoronary radiation therapy: An ultrasound dosimetry analysis for gamma and beta emitters SO CIRCULATION LA English DT Meeting Abstract C1 WASHINGTON UNIV,WASHINGTON,DC. NIST,GAITHERSBURG,MD 20899. GEORGE WASHINGTON UNIV HOSP,WASHINGTON,DC. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER HEART ASSOC PI DALLAS PA 7272 GREENVILLE AVENUE, DALLAS, TX 75231-4596 SN 0009-7322 J9 CIRCULATION JI Circulation PD OCT 21 PY 1997 VL 96 IS 8 SU S BP 1068 EP 1068 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA YC880 UT WOS:A1997YC88001066 ER PT J AU Toth, K Nagy, G Bui, TTL Jeney, J Choquette, SJ AF Toth, K Nagy, G Bui, TTL Jeney, J Choquette, SJ TI Planar waveguide ion-selective sensors SO ANALYTICA CHIMICA ACTA LA English DT Article DE sensors; ion-selective sensors; optical sensors; total internal reflection ID NEUTRAL IONOPHORES; MEMBRANE ELECTRODES; OPTODE MEMBRANES; WAVE-GUIDE; OPTICAL SENSORS; BULK OPTODES; POTASSIUM; RESPONSES; SURFACE; PLASMA AB A potassium ion-selective planar waveguide total internal reflection (TIR) mode optical sensor was prepared for flow injection application by casting thin film optode membranes onto a glass substrate. For this sensor, a potassium selective ionophore is incorporated in plasticized polyvinyl chloride film sensitized with a hydrogen selective ionophore. The sensor response to potassium ion is determined by measuring the attenuation of a HeNe laser propagated in this thin film device. The laser was coupled into and out of the sensor using grating couplers providing an inexpensive, environmentally stable sensor. The sensitivity of the waveguide based how injection device is approximately 0.05 mM K+, while the rate of analysis is about 180 samples per hour. (C) 1997 Elsevier Science B.V. C1 NIST,GAITHERSBURG,MD 20899. RP Toth, K (reprint author), TECH UNIV BUDAPEST,INST GEN & ANALYT CHEM,H-1111 BUDAPEST,HUNGARY. NR 34 TC 22 Z9 23 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD OCT 20 PY 1997 VL 353 IS 1 BP 1 EP 10 DI 10.1016/S0003-2670(97)00382-6 PG 10 WC Chemistry, Analytical SC Chemistry GA YH949 UT WOS:A1997YH94900001 ER PT J AU Dring, AR Linsky, J Murthy, J Henry, RC Moos, W VidalMadjar, A Audouze, J Landsman, W AF Dring, AR Linsky, J Murthy, J Henry, RC Moos, W VidalMadjar, A Audouze, J Landsman, W TI Lyman-alpha absorption and the D/H ratio in the local interstellar medium SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, abundance; ISM, bubbles; ISM, clouds; ISM, kinematics and dynamics; ultraviolet, ISM ID DEUTERIUM ABUNDANCE; GHRS OBSERVATIONS; CANIS-MAJORIS; SOLAR-SYSTEM; HST-GHRS; SIRIUS-A; GAS; CLOUDS; ULTRAVIOLET; IONIZATION AB Using the Goddard High Resolution Spectrograph onboard the Hubble Space Telescope, we have observed Ly alpha absorption against stellar chromospheres along six lines of sight, with additional observations of the Mg II H and K lines along five of the lines of sight and Fe II absorption along four of the lines of sight. We found absorption near the projected velocity of the local interstellar cloud (LIC) along three lines of sight. The velocity toward the stars beta Gem and sigma Gem was only marginally consistent with the LIC. The single interstellar component toward 31 Com had a velocity that was inconsistent with the projected LIC velocity. Three of the lines of sight showed a multicomponent velocity structure. For the star epsilon Eri we required an additional hot, low-density component which we have interpreted as a stellar hydrogen wall. The LIC temperatures derived from our data range from 7800 to 9700 K with values of the microturbulence parameter less than 2.0 km s(-1). The measured D/H ratio for the LIC along every sight line is consistent with a value of 1.6 x 10(-5), the best determined value being the beta Cas line of sight with D/H = 1.7 +/- 0.3 x 10(-5). C1 UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. INST ASTROPHYS,CTR NATL RECH SPATIALE,F-75014 PARIS,FRANCE. NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX INC,GREENBELT,MD 20771. RP Dring, AR (reprint author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218, USA. RI Murthy, Jayant/F-4433-2010 NR 50 TC 62 Z9 62 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 1997 VL 488 IS 2 BP 760 EP 775 DI 10.1086/304738 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YB992 UT WOS:A1997YB99200025 ER PT J AU Marticorena, B Bergametti, G Gillette, D Belnap, J AF Marticorena, B Bergametti, G Gillette, D Belnap, J TI Factors controlling threshold friction velocity in semiarid and arid areas of the United States SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOIL PARTICLES; DESERT SOILS; WIND EROSION; ELEMENTS; DUST AB A physical model was developed to explain threshold friction velocities u(*t) for particles of the size 60-120 mu m lying on a rough surface in loose soils for semiarid and arid parts of the United States. The model corrected for the effect of momentum absorption by the nonerodible roughness. For loose or disturbed soils the most important parameter that controls u(*t) is the aerodynamic roughness height z(0). For physical crusts damaged by wind the size of erodible crust pieces is important along with the roughness. The presence of cyanobacterial-lichen soil crusts roughens the surface, and the biological fibrous growth aggregates soil particles. Only undisturbed sandy soils and disturbed soils of all types would be expected to be erodible in normal wind storms. Therefore disturbance of soils by both cattle and humans is very important in predicting wind erosion as confirmed by our measurements. C1 NATL PK SERV, MOAB, UT 84532 USA. NOAA, AIR RESOURCES LAB, ATMOSPHER SCI MODELING DIV, RES TRIANGLE PK, NC 27711 USA. UNIV PARIS 12, LAB INTERUNIV SYST ATMOSPHER, CTR MULTIDISCIPLINAIRE, CRETEIL, FRANCE. NR 33 TC 117 Z9 126 U1 4 U2 17 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 OCT 20 PY 1997 VL 102 IS D19 BP 23277 EP 23287 DI 10.1029/97JD01303 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YC171 UT WOS:A1997YC17100004 ER PT J AU Pellegrini, NN Sikka, M Satija, SK Winey, KI AF Pellegrini, NN Sikka, M Satija, SK Winey, KI TI Segregation of a random copolymer from miscible blends SO MACROMOLECULES LA English DT Article ID SEQUENCE DISTRIBUTION; POLYMER INTERFACES; BLOCK COPOLYMERS; HOMOPOLYMER AB Thin film bilayers of deuterated polystyrene (dPS) and blends of deuterated poly(methyl methacrylate) (dPMMA) with a compositionally symmetric random copolymer of styrene and methyl methacrylate (P[S-0.49-ran-MMA]) were investigated by neutron reflectivity. Copolymer segregation to the free surface occurs upon spin-coating blends onto silicon substrates. Annealing the bilayers to equilibrium at 150 degrees C increases the segregation of the copolymer from the blend layers to the interface with dPS. Blends containing 5 and 10 vol % copolymer both exhibit this segregation behavior. For these blend compositions the interfacial segregation of copolymer from the miscible blends is insufficient to form a discrete layer. These results suggest that this random copolymer would be an interfacial specific additive. C1 UNIV PENN,DEPT MAT SCI & ENGN,PHILADELPHIA,PA 19104. UNIV PENN,RES STRUCT MATTER LAB,PHILADELPHIA,PA 19104. UNIV PENN,DEPT CHEM ENGN,PHILADELPHIA,PA 19104. NIST,CTR NEUTRON RES,GAITHERSBURG,MD 20899. NR 15 TC 8 Z9 8 U1 2 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD OCT 20 PY 1997 VL 30 IS 21 BP 6640 EP 6644 DI 10.1021/ma970586i PG 5 WC Polymer Science SC Polymer Science GA YD345 UT WOS:A1997YD34500034 ER PT J AU Lukin, MD Fleischhauer, M Zibrov, AS Robinson, HG Velichansky, VL Hollberg, L Scully, MO AF Lukin, MD Fleischhauer, M Zibrov, AS Robinson, HG Velichansky, VL Hollberg, L Scully, MO TI Spectroscopy in dense coherent media: Line narrowing and interference effects SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; SATURATION SPECTROSCOPY; DISPERSIVE PROPERTIES; QUANTUM COHERENCE; RUBIDIUM ATOMS; INDEX; ENHANCEMENT; TRANSITION; RESONANCES; REFRACTION AB Spectroscopic properties of coherently prepared, optically dense atomic media are studied experimentally and analyzed theoretically. It is shown that in such media the power broadening of the resonances can be substantially reduced. A density-dependent spectral narrowing of the electromagnetically induced transparency (EIT) window and novel, even narrower, resonances superimposed on the EIT line are observed in dense Rb vapor. A nonlinear two-photon spectroscopic technique based on coherent atomic media and combining high resolution with a large signal-to-noise ratio seems feasible. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. UNIV MUNICH,SEKT PHYS,D-80333 MUNICH,GERMANY. MAX PLANCK INST QUANTUM OPT,D-85748 GARCHING,GERMANY. PN LEBEDEV PHYS INST,MOSCOW 117924,RUSSIA. RP Lukin, MD (reprint author), TEXAS A&M UNIV,DEPT PHYS,COLLEGE STN,TX 77843, USA. RI Fleischhauer, Michael/G-6716-2011; Velichansky, Vladimir/M-4861-2015; Zibrov, Alexander/G-7419-2014 NR 34 TC 189 Z9 193 U1 2 U2 12 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD OCT 20 PY 1997 VL 79 IS 16 BP 2959 EP 2962 DI 10.1103/PhysRevLett.79.2959 PG 4 WC Physics, Multidisciplinary SC Physics GA YB664 UT WOS:A1997YB66400010 ER PT J AU Norman, BR Mackey, EA AF Norman, BR Mackey, EA TI Concentrations of iodine determined by pre-irradiation combustion and neutron activation analysis in powdered grass as a function of particle size SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE iodine; neutron activation analysis; reference material; grass ID TRACER EXPERIMENTS; ELEMENTS; MATRICES; SYSTEM; I-129; DIET; SOIL AB Pre-irradiation combustion of a sample to liberate iodine, trapping the iodine on charcoal and quantifying the element by neutron activation analysis (NAA), has proven to be a reliable technique for the determination of iodine in biological samples. This method has been applied to the determination of iodine content of a powdered grass material that was prepared by another laboratory for use as an in-house quality assurance material. Analyses of aliquots of the material yielded results that ranged from 0.45 to 0.96 mu g/g of iodine, so additional studies were undertaken in order to determine material homogeneity. Visual inspection indicated that the material was inhomogeneous with respect to particle size. To determine whether various sizes of particles contained different amounts of iodine, the material was sieved into four differently sized fractions and a portion of each fraction was analyzed. Variations in iodine concentration as a function of particle size were observed. The fraction containing particles of sizes greater than 350 mu m, the woody and fibrous plant parts, contained the least iodine (0.43 +/- 0.09 mu g/g, average +/- expanded uncertainty), while iodine concentrations in the subsequent three fractions increased with decreasing particle size with a maximum concentration of 0.89 +/- 0.13 mu g/g for particles less than 75 mu m. These results support conclusions of many researchers that trace element concentrations are inhomogeneously distributed in various cells and structural parts, and emphasize the importance of achieving uniform particle sizes during sample grinding and blending in the preparation of reference materials. (C) 1997 Elsevier Science B.V. C1 NATL INST STAND & TECHNOL,DIV ANALYT CHEM,GAITHERSBURG,MD 20899. NR 20 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD OCT 20 PY 1997 VL 205 IS 2-3 BP 151 EP 158 DI 10.1016/S0048-9697(97)00193-9 PG 8 WC Environmental Sciences SC Environmental Sciences & Ecology GA YD363 UT WOS:A1997YD36300006 ER PT J AU Ranjan, A Sinha, S Ghosh, PK Hastie, JW Bonnell, DW Paul, AJ Schenck, PK AF Ranjan, A Sinha, S Ghosh, PK Hastie, JW Bonnell, DW Paul, AJ Schenck, PK TI Monte Carlo simulations of plume evolution from laser ablation of graphite and barium titanate SO CHEMICAL PHYSICS LETTERS LA English DT Article AB Evolution of laser ablation products from graphite and barium titanate targets has been simulated using a Monte Carlo method, assuming elastic collisions. The calculated species arrival times and intensities, at a hypothetical detection plane, compare favorably with those obtained experimentally by time-resolved mass spectrometric sampling of the expanded vapor plumes. As such experiments are difficult to perform, the simulation method should prove useful for unstudied systems in defining the spatial and temporal distributions of species arriving for example, at a film deposition substrate. (C) 1997 Published by Elsevier Science B.V. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Ranjan, A (reprint author), INDIAN INST TECHNOL,DEPT CHEM,KANPUR 208016,UTTAR PRADESH,INDIA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD OCT 17 PY 1997 VL 277 IS 5-6 BP 545 EP 550 DI 10.1016/S0009-2614(97)00917-2 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YD629 UT WOS:A1997YD62900023 ER PT J AU Williams, KL Sander, LC AF Williams, KL Sander, LC TI Enantiomer separations on chiral stationary phases in supercritical fluid chromatography SO JOURNAL OF CHROMATOGRAPHY A LA English DT Review DE enantiomer separation; chiral stationary phases, SFC; reviews ID PERFORMANCE LIQUID-CHROMATOGRAPHY; SUBCRITICAL FLUID; CARBON-DIOXIDE; BETA-BLOCKERS; PACKED-COLUMNS; CHYROSINE-A; PHOSPHINE OXIDES; RESOLUTION; SFC; SELECTIVITY AB Supercritical fluid chromatography (SFC) has proven to be widely applicable fcr the separation of enantiomers on chiral stationary phases. Many of the chiral selectors utilized in gas and liquid chromatography have also been transferred to SFC. This article provides an overview of the types of separations reported on different classes of chiral stationary phases in SFC and includes comparisons of SFC to other chromatographic techniques. The importance of various chromatographic parameters in obtaining successful enantioseparations in SFC is also discussed. (C) 1997 Elsevier Science B.V. RP Williams, KL (reprint author), NIST,CHEM SCI & TECHNOL LAB,DIV ANALYT CHEM,GAITHERSBURG,MD 20899, USA. NR 57 TC 65 Z9 67 U1 2 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD OCT 17 PY 1997 VL 785 IS 1-2 BP 149 EP 158 DI 10.1016/S0021-9673(97)00575-X PG 10 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA YH098 UT WOS:A1997YH09800013 ER PT J AU Giachetti, RE Young, RE AF Giachetti, RE Young, RE TI A parametric representation of fuzzy numbers and their arithmetic operators SO FUZZY SETS AND SYSTEMS LA English DT Article DE fuzzy arithmetic; triangular fuzzy numbers; membership functions; arithmetic approximations AB Direct implementation of extended arithmetic operators on fuzzy numbers is computationally complex. Implementation of the extension principle is equivalent to solving a nonlinear programming problem, To overcome this difficulty many applications limit the membership functions to certain shapes, usually either triangular fuzzy numbers (TFN) or trapezoidal fuzzy numbers (TrFN). Then calculation of the extended operators can be performed on the parameters defining the fuzzy numbers, thus making the calculations trivial. Unfortunately the TFN shape is not closed under multiplication and division. The result of these operators is a polynomial membership function and the triangular shape only approximates the actual result. The linear approximation can be quite poor and may lead to incorrect results when used in engineering applications. We analyze this problem and propose six parameters which define parameterized fuzzy numbers (PFN), of which TFNs are a special case, We provide the methods for performing fuzzy arithmetic and show that the PFN representation is closed under the arithmetic operations. The new representation in conjunction with the arithmetic operators obeys many of the same arithmetic properties as TFNs. The new method has better accuracy and similar computational speed to using TFNs and appears to have benefits when used in engineering applications. (C) 1997 Elsevier Science B.V. C1 N CAROLINA STATE UNIV,DEPT IND ENGN,WORKGRP INTELLIGENT SYST DESIGN & MFG,RALEIGH,NC 27695. RP Giachetti, RE (reprint author), NIST,MFG SYST INTEGRAT DIV,BLDG 304,RM 4,GAITHERSBURG,MD 20899, USA. NR 23 TC 80 Z9 84 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-0114 J9 FUZZY SET SYST JI Fuzzy Sets Syst. PD OCT 16 PY 1997 VL 91 IS 2 BP 185 EP 202 DI 10.1016/S0165-0114(97)00140-1 PG 18 WC Computer Science, Theory & Methods; Mathematics, Applied; Statistics & Probability SC Computer Science; Mathematics GA YC160 UT WOS:A1997YC16000007 ER PT J AU Kane, SM Rufael, TS Gland, JL Huntley, DR Fischer, DA AF Kane, SM Rufael, TS Gland, JL Huntley, DR Fischer, DA TI Role of hydrogen in benzene formation from benzenethiol on the Ni(111) surface SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID VIBRATIONAL EELS; ADSORPTION; HYDRODESULFURIZATION; PT(111); DESULFURIZATION; SPECTROSCOPY; THIOPHENOL; MECHANISM; CATALYSTS; THIOLATE AB The role of surface hydrogen in the desulfurization of benzenethiol to form benzene on the Ni(111) surface has been explored in hydrogen pressures ranging between UHV and up to 7 x 10(-3) Torr. Hydrogen availability plays a significant role in the reaction of adsorbed benzenethiol, as demonstrated over a wide range of reaction conditions. Adsorbed hydrogen and phenylthiolate, formed from sulfur-hydrogen bond scission of the benzenethiol upon adsorption at 100 K, react with increasing temperature to produce the primary desorbing products benzene and hydrogen. The dominant benzene formation channel at high coverage occurs at 260 K, with a smaller benzene peak occurring at 290 K and a final benzene peak near 400 K, Increasing the availability of surface hydrogen does not significantly affect either the benzene yield or the benzene formation temperature for high benzenethiol coverage. The same reaction temperature is observed even for hydrogen pressures up to 7 x 10(-3) Ton, as indicated by in situ temperature programmed fluorescence yield near edge spectroscopy (TP-FYNES) experiments. For low coverages of phenylthiolate on the clean Ni(111) surface, benzene formation decreases substantially and the higher temperature processes become more important. Hydrogen preadsorption in the low benzenethiol coverage case dramatically increases the amount of benzene formed at 260 K and decreases the high-temperature peak. Deuterium incorporation following reaction with coadsorbed deuterium clearly indicates three distinct levels of isotope incorporation for the benzene: peaks at 260, 290, and 400 K. Incorporation of a single deuterium dominates for the peak at 260 K, indicating an adsorbed phenylthiolate intermediate dominates for this low-temperature process. Multiple incorporation dominates for the peak at 240 K, indicating a dehydrogenated intermediate of the ''benzyne'' type, which is also observed by vibrational spectroscopy. Benzene formed above 400 K includes even more extensive deuterium incorporation, suggesting an even more extensively dehydrogenated intermediate. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV MICHIGAN,ANN ARBOR,MI 48109. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. NR 23 TC 18 Z9 18 U1 1 U2 1 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 OCT 16 PY 1997 VL 101 IS 42 BP 8486 EP 8491 DI 10.1021/jp970988s PG 6 WC Chemistry, Physical SC Chemistry GA YB794 UT WOS:A1997YB79400013 ER PT J AU Muller, R Crutzen, PJ Grooss, JU Bruhl, C Russell, JM Gernandt, H McKenna, DS Tuck, AF AF Muller, R Crutzen, PJ Grooss, JU Bruhl, C Russell, JM Gernandt, H McKenna, DS Tuck, AF TI Severe chemical ozone loss in the Arctic during the winter of 1995-96 SO NATURE LA English DT Article ID POLAR VORTEX CONDITIONS; DEPLETION; STRATOSPHERE; ANTARCTICA; LIDAR; MLS AB Severe stratospheric ozone depletion is the result of perturbations of chlorine chemistry owing to the presence of polar stratospheric clouds (PSCs) during periods of Limited exchange of air between the polar vortex and midlatitudes and partial exposure of the vortex to sunlight(1-4). These conditions are consistently encountered over Antarctica during the austral spring. In the Arctic, extensive PSC formation occurs only during the coldest winters, when temperatures fall as low as those regularly found in the Antarctic(1,5,6). Moreover, ozone levels in late winter and early spring are significantly higher than in the corresponding austral season(1,7,8), and usually strongly perturbed by atmospheric dynamics(9-12). For these reasons, chemical ozone loss in the Arctic is difficult to quantify. Here we use the correlation between CH4 and O-3 in the Arctic polar vortex to discriminate between changes in ozone concentration due to chemical and dynamical effects(10). Our results indicate that 120-160 Dobson units (DU) of ozone were chemically destroyed between January and March 1996-a loss greater than observed in Antarctica in 1985, when the 'ozone hole' was first reported(13,14). This loss outweighs the expected increase in total ozone over the same period through dynamical effects, leading to an observed(6) net decrease of about 50 DU. This ozone loss arises through the simultaneous occurrence of extremely low Arctic stratospheric temperatures(6,15) and large stratospheric chlorine loadings. Comparable depletion is likely to recur because stratospheric cooling(16,17) and elevated chlorine concentrations(5,18) are expected to persist for several decades. C1 MAX PLANCK INST CHEM, D-55020 MAINZ, GERMANY. HAMPTON UNIV, DEPT PHYS, HAMPTON, VA 23658 USA. ALFRED WEGENER INST POLAR & MARINE RES, D-14473 POTSDAM, GERMANY. NOAA, AERON LAB, BOULDER, CO 80303 USA. RP Muller, R (reprint author), FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, INST STRATOSPHER CHEM ICG 1, POSTFACH 1913, D-52425 JULICH, GERMANY. RI Tuck, Adrian/F-6024-2011; Crutzen, Paul/F-6044-2012; Muller, Rolf/A-6669-2013; GrooSS, Jens-Uwe/A-7315-2013; McKenna, Daniel/E-7806-2014 OI Tuck, Adrian/0000-0002-2074-0538; Muller, Rolf/0000-0002-5024-9977; GrooSS, Jens-Uwe/0000-0002-9485-866X; McKenna, Daniel/0000-0002-4360-4782 NR 36 TC 128 Z9 130 U1 2 U2 19 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD OCT 16 PY 1997 VL 389 IS 6652 BP 709 EP 712 DI 10.1038/39564 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA YA959 UT WOS:A1997YA95900049 ER PT J AU Schantz, MM Nichols, JJ Wise, SA AF Schantz, MM Nichols, JJ Wise, SA TI Evaluation of pressurized fluid extraction for the extraction of environmental matrix reference materials SO ANALYTICAL CHEMISTRY LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; STANDARD REFERENCE MATERIAL; CARBON-DIOXIDE EXTRACTION; SUPERCRITICAL-FLUID; POLYCHLORINATED-BIPHENYLS; ORGANIC POLLUTANTS; SAMPLE PREPARATION; MARINE SEDIMENT; SOLIDS; CERTIFICATION AB Pressurized fluid extraction (PFE) has been evaluated for the extraction of selected polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCB) congeners, and chlorinated pesticides from the following reference materials: SRM 1649a (Urban Dust/Organics), SRM 1650 (Diesel Particulate Matter), SRM 2975 (Diesel Particulate Matter, Industrial Forklift), SRM 1941a (Organics in Marine Sediment), SRM 1944 (New York/New Jersey Waterway Sediment), SRM 2974 (Organics in Freeze-Dried Mussel Tissue), CARP-1 (Ground Whole Carp), and CARP-2 (Ground Whole Carp). Several solvent systems were evaluated for each reference material. PFE showed extraction efficiency comparable to that of Soxhlet extraction for the selected PAHs, PCB congeners, and chlorinated pesticides quantified in the air particulate, sediment, mussel tissue, and fish materials and greater extraction efficiencies for the higher molecular weight PAHs in the diesel particulate materials. C1 NIST,DIV ANALYT CHEM,GAITHERSBURG,MD 20899. NR 29 TC 188 Z9 194 U1 3 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD OCT 15 PY 1997 VL 69 IS 20 BP 4210 EP 4219 DI 10.1021/ac970299c PG 10 WC Chemistry, Analytical SC Chemistry GA YA446 UT WOS:A1997YA44600018 ER PT J AU Davis, S Anderson, DT Duxbury, G Nesbitt, DJ AF Davis, S Anderson, DT Duxbury, G Nesbitt, DJ TI Jet-cooled molecular radicals in slit supersonic discharges: Sub-Doppler infrared studies of methyl radical SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID HYPERFINE COUPLING-CONSTANTS; LASER ABSORPTION-SPECTROSCOPY; PULSED ELECTRICAL-DISCHARGE; HIGH-RESOLUTION; MICROWAVE-SPECTRUM; DIODE-LASER; VIBRATIONAL PREDISSOCIATION; TRANSIENT MOLECULES; DIPOLE-MOMENT; HF DIMER AB A novel high-intensity source of jet-cooled molecular radicals is described based on the combination of (i) slit supersonic expansions with (ii) pulsed electric discharges. The electrode bias configuration effectively confines the discharge to a region upstream of the supersonic expansion, which results both in efficient rotational cooling (T-rot approximate to 25 K) and high radical densities (>10(14)/cm(3)). In conjunction with direct absorption laser probe methods, this discharge source provides a general technique for high-resolution IR studies of jet-cooled radicals. Performance of the slit discharge system is demonstrated on v = 1<--0 rovibrarional transitions in jet-cooled OH radicals, which indicate sub-Doppler linewidths (Delta v approximate to 100 MHz) when probed along the slit expansion axis, The enhanced spectral resolution of the slit discharge geometry is utilized to probe the v(3)= 1<--0 asymmetric CH stretch vibration-rotation spectra of CH3 radical. Under sub-Doppler conditions, spin-rotation splittings are fully resolved and nuclear hyperfine splittings partially resolved in all of the transitions, permitting the first measure of Fermi contact interactions [a(f)(n)=-65.5(9) MHz, epsilon(bb)'' = -354(5) MHz, a(f)' = -65(2) MHz, epsilon(bb)' = -353(2) MHz] and therefore both the sign and magnitude of spin-polarization effects for CH3 under isolated gas-phase conditions. The results permit direct comparison with high level ab initio calculations, and highlight a clear trend in spin-polarization effects between condensed and gas-phase behavior. (C) 1997 American Institute of Physics. C1 UNIV COLORADO, DEPT CHEM & BIOCHEM, BOULDER, CO 80309 USA. NIST, BOULDER, CO 80309 USA. RP Davis, S (reprint author), UNIV COLORADO, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. NR 90 TC 81 Z9 82 U1 5 U2 27 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 15 PY 1997 VL 107 IS 15 BP 5661 EP 5675 DI 10.1063/1.474259 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YA587 UT WOS:A1997YA58700004 ER PT J AU Tisch, TD Ramp, SR AF Tisch, TD Ramp, SR TI Moored observations of the current and temperature structure over the continental slope off central California 2. The energetics of the flow off Point Sur SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID COASTAL TRANSITION ZONE; GULF-STREAM DYNAMICS; KUROSHIO EXTENSION; CURRENT SYSTEM; MEAN FLOW; OCEAN CIRCULATION; EDDY ENERGETICS; VERTICAL MOTION; FLORIDA CURRENT; KINETIC-ENERGY AB The data from two current meter moorings off Point Sur, California, were analyzed to examine the energy transfers over the continental slope in the California Current system (CCS). The method used was to calculate terms in the heat equation at intermediate depths between instruments, using the thermal wind relation to estimate the horizontal temperature gradients from the vertical shear. Time series of u, v, and T were collected for 17 months (May 1989 to October 1990) at site P2 on the 800-m isobath and for 12 months (May 1990 to May 1991) at site P3, 25 km farther offshore on the 1800-m isobath. Instrument depths were 100, 350, and 500 m at both moorings plus 1000 m at site P3. Mean values of the energy conversion terms were computed at sites P2 and P3 at 225 m depth and at site P2 at 425 m depth. The local change of eddy potential energy (EPE) was approximately balanced (partial derivative EPE/partial derivative t approximate to 0) for each case but the dynamics were quite different. At P2 225, the sources of EPE were advection by the mean flow and baroclinic instability, which converted mean potential energy (MPE) to EPE. The losses came from eddy advection out of the region and the vertical eddy heat flux (VEHF), which converted EPE to eddy kinetic energy (EKE). At P2 425, baroclinic instability provided the major source of EPE. This, plus a small positive contribution from the VEHF, was balanced by advection of EPE out of the region by both the mean flow and the eddies. At P3 225, mean advection and baroclinic instability were negligible, and the downward eddy heat flux (VEHF) was balanced by advection of heat out of the region by the eddies. Time series of terms in the EPE equation were used to examine high energy transfer events at both moorings, Events at P2 involved both horizontal and vertical processes and had longer timescales (several days to weeks) than those at P3, which had much shorter timescales (2-5 days) and were: dominated by vertical processes. Compared to the Gulf Stream, the mean baroclinic instability at P2 (both depths) was smaller by at least a factor of 10. A term-by-term comparison between the mean values off Point Sur and the Kuroshio Extension showed different processes, with the eddies gaining strength at the expense of the mean flow off Point Sur and the opposite occurring in the Kuroshio Extension. C1 USN, Postgrad Sch, Dept Oceanog, Monterey, CA 93943 USA. RP Tisch, TD (reprint author), NOAA, Off Ocean & Atmospher Res, R-PDC,1315 E W Highway, Silver Spring, MD 20910 USA. NR 40 TC 4 Z9 4 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD OCT 15 PY 1997 VL 102 IS C10 BP 22903 EP 22920 DI 10.1029/97JC02329 PG 18 WC Oceanography SC Oceanography GA YL698 UT WOS:000070983400002 ER PT J AU Cokelet, ED Stabeno, PJ AF Cokelet, ED Stabeno, PJ TI Mooring observations of the thermal structure, salinity, and currents in the SE Bering Sea basin SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID THERAGRA-CHALCOGRAMMA; CONTINENTAL-SLOPE; WALLEYE POLLOCK; CIRCULATION AB Utilizing recently developed deep-sea mooring technology, we present the first interannual time series measurements of the ocean temperature, salinity, and velocity fields in the Bering Sea basin. These were made during spring and summer of 1992 and 1993 and late winter to summer of 1994, in 2195 m of water. Results show a weak background flow of similar to 5 cm/s with semidiurnal tides superimposed. Anticyclonic (clockwise) eddies pass by sporadically, inducing currents up to similar to 80 cm/s and depressing the isopycnals and isotherms up to similar to 200 m. The thermal structure in the upper 400 m shows a deep temperature maximum from warm Alaskan Stream inflows and a minimum above due to winter cooling. A sea surface cooling event was observed in the late winter of 1994, with cold water penetrating to similar to 120-m depth. Spring warming begins in late April to early May of each year, marked by the arrival of the 3.75 degrees C isotherm. The local wind plays little role in forcing ocean currents at the site except at the inertial frequency. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Cokelet, ED (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. NR 37 TC 22 Z9 23 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD OCT 15 PY 1997 VL 102 IS C10 BP 22947 EP 22964 DI 10.1029/97JC00881 PG 18 WC Oceanography SC Oceanography GA YL698 UT WOS:000070983400005 ER PT J AU Ando, K McPhaden, MJ AF Ando, K McPhaden, MJ TI Variability of surface layer hydrography in the tropical Pacific Ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID WESTERN EQUATORIAL PACIFIC; NINO SOUTHERN OSCILLATION; EL-NINO; MIXED-LAYER; EASTERN PACIFIC; BARRIER-LAYER; TOGA-COARE; TEMPERATURE; ATMOSPHERE; CIRCULATION AB The purpose of this study is to examine the variation of ocean surface layer hydrography on interannual timescales in the tropical Pacific Ocean using conductivity-temperature-depth measurements from 1976 to 1994. We demonstrate that associated with interannual variations in atmospheric forcing, there were distinct changes in mixed layer temperature, salinity, depth, and barrier layer thickness between normal, El Nino, and La Nina time periods. During El Nino a warm, fresh mixed layer accompanied by an underlying barrier layer develops in the central and eastern Pacific in association with increased precipitation and reduced trade wind forcing. Conversely, during La Nina, when unusually cold conditions prevail in the central and eastern equatorial Pacific and the warm pool is confined to the far western Pacific, a thick barrier layer is found west of 160 degrees E. Statistically, we demonstrate that barrier layers occur with increasing frequency as mixed layer temperatures increase from 20 degrees C to 30 degrees C, suggesting that barrier layer thickness may be one of the factors affecting surface temperatures. The physical mechanism underlying this relationship is likely to be related to the reduced efficiency of vertical turbulent mixing in cooling the surface via entrainment of thermocline water when the barrier layer is thick. Changes in mixed layer temperature, on the other hand, can affect precipitation and therefore mixed-layer salinity, leading to the possibility of feedbacks on interannual timescales involving the mixed-layer temperature balance and the hydrologic cycle over the ocean. The extent to which such feedbacks, if operative, may influence the detailed evolution of large-scale, lower-frequency variability in the tropical Pacific needs to be critically assessed in the context of coupled ocean-atmosphere models. C1 Japan Marine Sci & Technol Ctr, Yokosuka, Kanagawa 237, Japan. NOAA, Pacific Marine Environm Lab, Seattle, WA 98195 USA. RP Ando, K (reprint author), Japan Marine Sci & Technol Ctr, 2-15 Natsushima, Yokosuka, Kanagawa 237, Japan. EM mcphaden@pmel.noaa.gov RI 安藤, 健太郎/F-6685-2014; McPhaden, Michael/D-9799-2016 NR 58 TC 129 Z9 130 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD OCT 15 PY 1997 VL 102 IS C10 BP 23063 EP 23078 DI 10.1029/97JC01443 PG 16 WC Oceanography SC Oceanography GA YL698 UT WOS:000070983400012 ER PT J AU Zugenmaier, P Bluhm, TL Deslandes, Y Orts, WJ Hamer, GK AF Zugenmaier, P Bluhm, TL Deslandes, Y Orts, WJ Hamer, GK TI Diffraction studies on metal free phthalocyanines (beta-H2Pc and X-H2Pc) SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID CRYSTAL-STRUCTURE; RIETVELD ANALYSIS AB The crystal structure of the beta-polymorph of metal free phthalocyanine (beta-H2Pc) was redetermined from single crystals to obtain precise placements of the hydrogen atoms and a precise model for the X-polymorph (X-H2Pc) for which only limited data from different diffraction techniques are available. Partial occupancy for the hydrogens fixed to the nitrogens in the inner ring was found leading to a highly symmetric phthalocyanine molecule. Careful evaluation of X-ray, electron and neutron diffraction data for X-H(2)Pe results in an orthorhombic unit cell with a = 2.10 nm, b = 0.491 nm, c = 2.31 nm, space group Pna2(1) containing four molecules in contrast to a recent determination of Oka and Okada who proposed a monoclinic unit cell with two molecules. As expected the phthalocyanine molecules pack in stacks. The overlap of molecules within one stack matches the current ideas for photosensitive phthalocyanine pigments. C1 DOCUMENT CO XEROX,WEBSTER,NY 14580. NATL RES COUNCIL CANADA,INST CHEM PROC & ENVIRONM TECHNOL,OTTAWA,ON K1A 0R6,CANADA. NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. XEROX RES CTR CANADA LTD,MISSISSAUGA,ON L5K 2L2,CANADA. RP Zugenmaier, P (reprint author), TECH UNIV CLAUSTHAL,INST PHYS CHEM,D-38678 CLAUSTHAL ZELLERF,GERMANY. NR 6 TC 21 Z9 21 U1 0 U2 3 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD OCT 15 PY 1997 VL 32 IS 20 BP 5561 EP 5568 DI 10.1023/A:1018672423851 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA YD608 UT WOS:A1997YD60800031 ER PT J AU Gierczak, T Burkholder, JB Talukdar, RK Mellouki, A Barone, SB Ravishankara, AR AF Gierczak, T Burkholder, JB Talukdar, RK Mellouki, A Barone, SB Ravishankara, AR TI Atmospheric fate of methyl vinyl ketone and methacrolein SO JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY LA English DT Article DE methyl vinyl ketone; methacrolein; OH rate coefficient; absorption cross section; quantum yield ID SINGLY SUBSTITUTED METHYLPROPENALS; EXCITED-STATE GEOMETRIES; OXIDATION-PRODUCTS; OH; HYDROCARBONS; ISOPRENE; PHOTOLYSIS; MECHANISM; RADICALS; CH3OOH AB The rate coefficients for the reaction of OH with methyl vinyl ketone (MVK, CH3C(O)CHCH2) and methacrolein (MACR, CH2C(CH3) CHO) between 232 and 378 K were measured using the pulsed laser photolysis-pulsed laser induced fluorescence (PP-PLIF) technique. The rate coefficient data can be expressed in the Arrhenius form as k(1)(OH + MVK) = (2.67 +/- 0.45) x 10(-12) exp( (452 +/- 130)/T) and k(2)(OH + MACR) = (7.73 +/- 0.65) x 10(-12) exp((379 +/- 46)/T) cm(3) molecule(-1) s(-1), where the error limits are 2 sigma and include estimated systematic errors. The UV absorption cross-sections of MVK and MACR were measured over the wavelength range 250-395 nm using a diode array spectrometer. Absolute quantum yields for loss of MVK and MACR were measured at 308, 337, and 351 nm. The MACR quantum yield, Phi(MACR), was <0.01. The MVK quantum yield was both pressure and wavelength dependent and is represented by the expression: Phi(0)(lambda,P) < exp [-0.055(lambda - 308)]/(5.5 + 9.2 x 10(-19)N) where lambda is measured in nm and N is the number density in molecule cm(-3). Atmospheric loss rate calculations using these results show that the primary loss process for both MVK and MACR is the reaction with OH radicals throughout the troposphere. (C) 1997 Elsevier Science S.A. C1 NOAA,AERON LAB,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RI TALUKDAR, RANAJIT/G-4530-2013; Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011; Mellouki, Abdelwahid/H-5219-2011 OI TALUKDAR, RANAJIT/0000-0001-6017-8431; Mellouki, Abdelwahid/0000-0002-6594-5262 NR 24 TC 79 Z9 80 U1 1 U2 27 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 1010-6030 J9 J PHOTOCH PHOTOBIO A JI J. Photochem. Photobiol. A-Chem. PD OCT 15 PY 1997 VL 110 IS 1 BP 1 EP 10 DI 10.1016/S1010-6030(97)00159-7 PG 10 WC Chemistry, Physical SC Chemistry GA YF957 UT WOS:A1997YF95700001 ER PT J AU Ettedgui, E Davis, GT Hu, B Karasz, FE AF Ettedgui, E Davis, GT Hu, B Karasz, FE TI Degradation of polymer-based light-emitting diodes during operation SO SYNTHETIC METALS LA English DT Article DE light-emitting diodes; electrodes; scanning electron microscopy; atomic force microscopy; poly(phenylene vinylene) and derivatives ID POLY(P-PHENYLENEVINYLENE); ELECTROLUMINESCENCE; EFFICIENCY; EMISSION AB Segmented block copolymers consisting of conjugated-nonconjugated sequences an useful chromophores in polymer LEDs and can lead to efficient devices of high luminance. The lifetime of such diodes depends on numerous chemical and physical interactions. Some of these pertaining to the chromophore/electrode interface can be usefully studied by optical and various electron microscopies. Zn typical diodes studied here, failure is associated inter alia with irregularities in the spin-coated polymer films. Atomic force microscopy provides a more detailed examination of the morphology of the polymer films. (C) 1997 Elsevier Science S.A. C1 NIST,DIV POLYMER,GAITHERSBURG,MD 20899. UNIV MASSACHUSETTS,DEPT POLYMER SCI & ENGN,AMHERST,MA 01003. RI Hu, Bin/A-2954-2015 OI Hu, Bin/0000-0002-1573-7625 NR 20 TC 18 Z9 18 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD OCT 15 PY 1997 VL 90 IS 1 BP 73 EP 76 DI 10.1016/S0379-6779(97)81229-5 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA YF881 UT WOS:A1997YF88100013 ER PT J AU Meyer, KW Bohn, JL Greene, CH Esry, BD AF Meyer, KW Bohn, JL Greene, CH Esry, BD TI Dominance of short-range correlations in photoejection-induced excitation processes SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID ELECTRON-ATOM IONIZATION; R-MATRIX METHODS; INTERMEDIATE ENERGIES; DOUBLE PHOTOIONIZATION; HYDROGEN-ATOMS; THRESHOLD LAW; SCATTERING; HELIUM AB Much attention has been focused in recent decades on the process of double photoejection, with comparatively little study of the closely related process of photoejection plus excitation of the residual fragment. We present new calculations for the process hv + He --> He+(n) + e(-), which quantitatively reproduces recent experimental measurements (Wehlitz R er al 1997 J. Phys. B: Ar. Mel. Opt. Phys. 30 L51). These calculations show that the controlling electron correlations are confined to distances much smaller than the extent (similar to 3n(2)/Z au) of the He+(n) state that is excited. C1 UNIV COLORADO,JILA,BOULDER,CO 80309. NATL INST STAND & TECHNOL,QUANTUM PHYS DIV,BOULDER,CO 80309. RP Meyer, KW (reprint author), UNIV COLORADO,DEPT PHYS,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 28 TC 9 Z9 9 U1 0 U2 0 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 OCT 14 PY 1997 VL 30 IS 19 BP L641 EP L647 DI 10.1088/0953-4075/30/19/003 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA YB249 UT WOS:A1997YB24900003 ER PT J AU Bagchi, S Krause, SJ Roitman, P AF Bagchi, S Krause, SJ Roitman, P TI Dose dependence of microstructural development of buried oxide in oxygen implanted silicon-on-insulator material SO APPLIED PHYSICS LETTERS LA English DT Article AB The effect of implantation dose on microstructural development of the buried oxide (BOX) of 200 keV oxygen implanted Si was studied by electron microscopy, A continuous BOX layer with a low density of Si islands was obtained for a dose of 0.45 X 10(18) cm(-2), following high temperature annealing. At a lower dose of 0.225 x 10(18) cm(-2) a layer did not form, but only disjointed, isolated, oxide precipitates developed. At a higher dose, 0.675 X 10(18) cm(-2), a continuous BOX layer with a high density of Si islands formed. Microstructures of intermediate-temperature annealed samples showed the formation of oxide precipitates at preferred depths, the morphology being dose dependent. The final microstructure of the BOX is strongly influenced by the evolution of the oxide precipitates during annealing. A qualitative mechanism is proposed for the dose-dependent behavior of BOX formation during the annealing process. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL, DIV SEMICOND ELECT, GAITHERSBURG, MD 20899 USA. RP ARIZONA STATE UNIV, DEPT CHEM BIO & MAT ENGN, TEMPE, AZ 85287 USA. NR 6 TC 24 Z9 25 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD OCT 13 PY 1997 VL 71 IS 15 BP 2136 EP 2138 DI 10.1063/1.119360 PG 3 WC Physics, Applied SC Physics GA YA209 UT WOS:A1997YA20900026 ER PT J AU Kob, W Donati, C Plimpton, SJ Poole, PH Glotzer, SC AF Kob, W Donati, C Plimpton, SJ Poole, PH Glotzer, SC TI Dynamical heterogeneities in a supercooled Lennard-Jones liquid SO PHYSICAL REVIEW LETTERS LA English DT Article ID GLASS-FORMING LIQUIDS; MODE-COUPLING THEORY; MULTIDIMENSIONAL NMR; 2-DIMENSIONAL LIQUID; ORTHO-TERPHENYL; RELAXATION; TRANSITION; MIXTURE; BEHAVIOR; MEMORY AB We present the results of a molecular dynamics computer simulation study in which we investigate whether a supercooled Lennard-Jones liquid exhibits dynamical heterogeneities. We evaluate the non-Gaussian parameter for the self part of the van Hove correlation function and use it to identify ''mobile'' particles. We find that these particles form clusters whose sizes grow with decreasing temperature. We also find that the relaxation time of the mobile particles is significantly shorter than that of the average particle, and that this difference increases with decreasing temperature. C1 NATL INST STAND & TECHNOL, CTR THEORET & COMPUTAT MAT SCI, GAITHERSBURG, MD 20899 USA. NATL INST STAND & TECHNOL, DIV POLYMERS, GAITHERSBURG, MD 20899 USA. SANDIA NATL LABS, PARALLEL COMPUTAT SCI DEPT, ALBUQUERQUE, NM 87185 USA. UNIV WESTERN ONTARIO, DEPT APPL MATH, LONDON, ON N6A 5B7, CANADA. RP UNIV MAINZ, INST PHYS, STAUDINGER WEG 7, D-55099 MAINZ, GERMANY. RI Poole, Peter/C-7943-2009; Donati, Claudio/J-5180-2012; Kob, Walter/L-7010-2013; OI Poole, Peter/0000-0001-5985-0585; Kob, Walter/0000-0001-7405-2178; Donati, Claudio/0000-0001-8688-1651 NR 30 TC 628 Z9 630 U1 4 U2 88 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 OCT 13 PY 1997 VL 79 IS 15 BP 2827 EP 2830 DI 10.1103/PhysRevLett.79.2827 PG 4 WC Physics, Multidisciplinary SC Physics GA YA302 UT WOS:A1997YA30200019 ER PT J AU Udovic, TJ Huang, Q Rush, JJ AF Udovic, TJ Huang, Q Rush, JJ TI Theoretical prediction of the structure of insulating YH3 - Comment SO PHYSICAL REVIEW LETTERS LA English DT Editorial Material ID YTTRIUM C1 UNIV MARYLAND,DEPT MAT & NUCL ENGN,COLLEGE PK,MD 20742. RP Udovic, TJ (reprint author), NATL INST STAND & TECHNOL,CTR NEUTRON RES,GAITHERSBURG,MD 20899, USA. NR 6 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD OCT 13 PY 1997 VL 79 IS 15 BP 2920 EP 2920 DI 10.1103/PhysRevLett.79.2920 PG 1 WC Physics, Multidisciplinary SC Physics GA YA302 UT WOS:A1997YA30200043 ER PT J AU DiMarzio, EA Mandell, AJ AF DiMarzio, EA Mandell, AJ TI Phase transition behavior of a linear macromolecule threading a membrane SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POLYMER; SURFACE; HEAD AB The problem of a polymer molecule whose two ends reside on opposite sides of a membrane or partition separating two solutions is solved exactly in the limit of no self-excluded volume. The monomers can go from one side of the membrane to the other only by threading serially through one hole in the membrane. The ends can be free, confined to run freely on the membrane surfaces, or be fixed to specific points on the membrane. It is found that the equilibrium thermodynamic phase transition is first order in all cases so that slight changes in pH, ionic strength, or temperature can move the polymer from being completely on one side of the membrane to being completely on the other side. Application to two biological problems are suggested: (1) the breaching of cell walls by the nuclear material of T2 bacteriophages, and (2) the transport of drugs that are affixed to these translocating polymers. The relation of this newly discovered transition to four other phase transitions that occur in isolated macromolecules (helix-random coil; equilibrium polymerization; polymer collapse; surface adsorption) is briefly discussed. (C) 1997 American Institute of Physics. C1 EMORY UNIV,SCH MED,ATLANTA,GA 30322. RP DiMarzio, EA (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 24 TC 83 Z9 83 U1 3 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 8 PY 1997 VL 107 IS 14 BP 5510 EP 5514 DI 10.1063/1.474256 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XZ871 UT WOS:A1997XZ87100022 ER PT J AU Zakharov, O Cohen, ML Louie, SG Penn, DR AF Zakharov, O Cohen, ML Louie, SG Penn, DR TI Dynamical screening at the metal-semiconductor interface and excitonic superconductivity SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID MECHANISM; MODEL AB We examine the possibility of excitonic superconductivity at a metal-semiconductor interface. An ab initio RPA calculation of the screened Coulomb electron-electron interaction is performed for the silicon-jellium multilayer model. The superconducting kernel for this multilayered system is found to be positive in the whole frequency range considered. We show that the inclusion of local field effects does not change the sign of the kernel and thus does not enhance the excitonic mechanism. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NIST,DIV ELECTRON & OPT PHYS,PHYS LAB,TECHNOL ADM,DEPT COMMERCE,GAITHERSBURG,MD 20899. RP Zakharov, O (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 17 TC 0 Z9 0 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD OCT 6 PY 1997 VL 9 IS 40 BP 8501 EP 8514 DI 10.1088/0953-8984/9/40/016 PG 14 WC Physics, Condensed Matter SC Physics GA YB246 UT WOS:A1997YB24600015 ER PT J AU Unguris, J Celotta, RJ Pierce, DT AF Unguris, J Celotta, RJ Pierce, DT TI Determination of the exchange coupling strengths for Fe/Au/Fe SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC MULTILAYERS; LAYERS; OSCILLATIONS; GROWTH; REFLECTION; MONOLAYERS; THICKNESS; PERIOD; IRON AB We measure, as a function of interlayer thickness, the magnitude of the bilinear exchange coupling in an Fe/Au/Fe trilayer, to investigate the existing order of magnitude discrepancy between theory and experiment. We use Fe whisker substrates, scanning electron microscopy polarization analysis, and reflection high-energy electron diffraction to monitor the sample's magnetic and physical structure, and confocal magneto-optical Kerr effect to determine the coupling. We determine the exchange coupling strengths of the individual oscillating terms. The total bilinear coupling strength is -1.9 +/- 0.2 mJ/m(2), for a Au interlayer thickness of 4 monolayers, in substantial agreement with current theory. RP Unguris, J (reprint author), NATL INST STAND & TECHNOL,ELECTRON PHYS GRP,GAITHERSBURG,MD 20899, USA. RI Unguris, John/J-3989-2014 NR 25 TC 71 Z9 71 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 OCT 6 PY 1997 VL 79 IS 14 BP 2734 EP 2737 DI 10.1103/PhysRevLett.79.2734 PG 4 WC Physics, Multidisciplinary SC Physics GA XZ544 UT WOS:A1997XZ54400034 ER PT J AU Cahn, JW Fife, P Penrose, O AF Cahn, JW Fife, P Penrose, O TI A phase-field model for diffusion-induced grain-boundary motion SO ACTA MATERIALIA LA English DT Article ID DISCONTINUOUS PRECIPITATION; DRIVING FORCE; MIGRATION; MECHANISM; GROWTH; SYSTEM AB We model diffusion-induced grain boundary motion (DIGM) with a pair of differential equations: tau partial derivative phi/partial derivative t = - phi + delta(2) del(2) phi - epsilon partial derivative p(phi, u)/partial derivative phi if - 1 < phi < 1, else partial derivative phi/partial derivative t = 0 partial derivative u/partial derivative t = del.[D(phi)del v], where v = u + epsilon partial derivative p(phi, u)/partial derivative u. Here u represents the concentration of solute atoms, phi takes the values +1 and-1 in the two perfect crystal grains and intermediate values in the boundary between them, tau, delta and epsilon are constants characterizing the material, p(phi, u) is an interaction energy density, and the diffusivity D(phi) is large in the grain boundary (-1 < phi < 1) but zero in the grains (phi = +/- 1). The model is thermodynamically consistent, being derivable from a free energy functional. The aim of the work is to understand what interactions p(phi, u) can or cannot account for the observed results. For small epsilon the speed of travelling wave solutions can be calculated approximately using a successive approximations scheme. The results indicate that the simple interaction, p(phi, u) = u(1 - phi(2)), corresponding to differing solubility in the grain boundary and in the bulk crystal, cannot explain all the observed data. An interaction modelling the elastic coherency strain energy is also considered, and its consequences are consistent with the observed features of DIGM in nearly all cases. (C) 1997 Acta Metallurgica Inc. C1 UNIV UTAH, SALT LAKE CITY, UT USA. HERIOT WATT UNIV, EDINBURGH, MIDLOTHIAN, SCOTLAND. RP NIST, GAITHERSBURG, MD 20899 USA. NR 35 TC 56 Z9 56 U1 2 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD OCT PY 1997 VL 45 IS 10 BP 4397 EP 4413 DI 10.1016/S1359-6454(97)00074-8 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA XY517 UT WOS:A1997XY51700039 ER PT J AU Garboczi, EJ Bentz, DP AF Garboczi, EJ Bentz, DP TI Analytical formulas for interfacial transition zone properties SO ADVANCED CEMENT BASED MATERIALS LA English DT Article; Proceedings Paper CT MRS Symposium HH on Structure-Property Relationships in Hardened Cement Pastes and Composites CY DEC 02-06, 1996 CL BOSTON, MA SP Mat Res Soc DE concrete; interfacial transition zone; cement; elastic moduli; conductivity; shrinkage ID DC ELECTRICAL-CONDUCTIVITY; PORE STRUCTURE; CONCRETE; MORTAR; PASTE AB Two analytical results are presented that are of use to concrete material technologists. Using a model of concrete in which the aggregates are spherical, but with an arbitrary size distribution, a result from statistical geometry can be used to accurately give the total interfacial transition zone (ITZ) volume for any width ITZ and any volume fraction of aggregates. In reality, the ITZ contains a gradient of porosity and therefore a gradient of properties. When only a small volume fraction of aggregates is present (called the dilute limit), it is possible to analytically solve for the effect of the ITZ on the overall concrete properties. This calculation can be carried out for the effective linear elastic moduli, linear electrical conductivity/ionic diffusivity, and linear thermal/moisture shrinkage/expansion. The details of the calculation are summarized and applications described. Published by Elsevier Science Ltd. RP Garboczi, EJ (reprint author), NIST,BLDG MAT DIV,ROOM B350,BLDG 226,GAITHERSBURG,MD 20899, USA. NR 24 TC 120 Z9 132 U1 4 U2 24 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 1065-7355 J9 ADV CEM BASED MATER JI Adv. Cem. Based Mater. PD OCT-NOV PY 1997 VL 6 IS 3-4 BP 99 EP 108 DI 10.1016/S1065-7355(97)81592-1 PG 10 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA YK131 UT WOS:A1997YK13100004 ER PT J AU Atha, DH O'Connell, C Wenz, HM AF Atha, DH O'Connell, C Wenz, HM TI Detection of p53 point mutations by CE and SG electrophoresis SSCP. Identification of specific mutations by their unique temperature profiles. SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Appl Biosyst Inc, PE, Foster City, CA 94404 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1997 VL 61 IS 4 SU S MA 320 BP A60 EP A60 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA YQ995 UT WOS:000071446000322 ER PT J AU Levin, BC Cheng, H Reeder, DJ AF Levin, BC Cheng, H Reeder, DJ TI A human mitochondrial DNA standard deference material for quality control in mutation detection, medical diagnosis, and forensic identification. SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 USA. Geocenters Inc, Newton Ctr, MA USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1997 VL 61 IS 4 SU S MA 2291 BP A392 EP A392 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA YQ995 UT WOS:000071446002293 ER PT J AU Fulcrand, H Hapiot, P Neta, P Pinson, J Rolando, C AF Fulcrand, H Hapiot, P Neta, P Pinson, J Rolando, C TI Electrochemical and radiolytic oxidation of naturally occurring phenols SO ANALUSIS LA English DT Article ID ELECTRON REDOX POTENTIALS; CYCLIC VOLTAMMETRY; CONIFERYL ALCOHOL; LIGNIN; ULTRAMICROELECTRODES; THIOACIDOLYSIS; MECHANISM; RADICALS; KINETICS; STEP AB The combined use of electrochemical and radiolytic techniques permits elucidation of the mechanism of oxidation of phenols and characterization of the intermediates. C1 Inst Prod Vigne, Lab Polymeres & Tech Physicochim, F-30460 Montpellier, France. Univ Paris 07, Electrochim Mol Lab, CNRS, UMR 7591, F-75251 Paris 05, France. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Ecole Normale Super, Dept Chim, URA 1679, F-75231 Paris 05, France. RP Fulcrand, H (reprint author), Inst Prod Vigne, Lab Polymeres & Tech Physicochim, 9 Pl Viala, F-30460 Montpellier, France. RI PINSON, Jean/L-7028-2013; Pinson, Jean/M-9116-2016 NR 43 TC 4 Z9 4 U1 0 U2 4 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0365-4877 J9 ANALUSIS JI Analusis PD OCT PY 1997 VL 25 IS 8 BP M38 EP M43 PG 6 WC Chemistry, Analytical SC Chemistry GA YT102 UT WOS:000071564200009 ER PT J AU Ott, AK Casey, SM Leone, SR AF Ott, AK Casey, SM Leone, SR TI Laser ionization measurements of gaseous gallium atom desorption from GaAs(100) during molecular beam epitaxy SO APPLIED SURFACE SCIENCE LA English DT Article DE desorption; mass spectrometry; gallium; GaAs(100) ID ENERGY ELECTRON-DIFFRACTION; GROWTH; TEMPERATURES; LIMITATIONS; GENERATION; (AL,GA)AS; RADIATION; KRYPTON; XENON; GAAS AB The desorbed fluxes of gallium atoms from a GaAs(100) substrate during GaAs growth in the temperature range 550 to 1015 K are directly measured with laser single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS). At substrate temperatures above 900 K, Ga atoms desorb from the bulk GaAs wafer. The activation energy for this desorption under neither an incident As nor Ga flux is 4.7 +/- 0.2 eV. Under an incident As-4 flux, the measured activation energy for Ga desorption from the bulk is 5.2 +/- 0.2 eV. At substrate temperatures between 600 K and 900 K, scattered gallium atoms are detected during GaAs homoepitaxy with incident As-4 and Ga fluxes. The flux of Ga atoms increases with increasing GaAs surface temperature, but no flux is observed when the Ga oven shutter is closed. Simultaneous measurements of reflection high-energy electron diffraction (RHEED) specular beam intensity oscillations and scattered As-2 and As-4 mass signals are recorded. The sticking probability of Ga atoms during GaAs homoepitaxy derived from the RHEED results is found to decrease from unity to 0.92 +/- 0.02 with increasing temperature. The desorbing flux of Ga atoms linearly increases with incident Ga flux and is not appreciably affected by changes in the incident As-4 flux. A precursor mediated adsorption model for Ga atoms on GaAs(100) is discussed to interpret the results. (C) 1997 Elsevier Science B.V. C1 NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,QUANTUM PHYS DIV,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NR 23 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD OCT PY 1997 VL 119 IS 3-4 BP 301 EP 309 DI 10.1016/S0169-4332(97)00191-8 PG 9 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA YC749 UT WOS:A1997YC74900017 ER PT J AU Ferguson, RL Korfmacher, K AF Ferguson, RL Korfmacher, K TI Remote sensing and GIS analysis of seagrass meadows in North Carolina, USA SO AQUATIC BOTANY LA English DT Article DE seagrass; remote sensing; Landsat TM; land cover ID AQUATIC VEGETATION; RESOURCES; IMAGERY; SOUND; SEA; TM AB Seagrass meadows are a valuable and vulnerable resource which supports coastal fisheries. Spatial monitoring of seagrass meadows can improve coastal management and research with baseline inventories of change in location and areal extent through time. Vertical aerial photography is an effective but expensive approach for monitoring seagrass meadows. Remote sensing with Landsat TM is less expensive but image selection is critical because environmental factors affect detection of seagrass meadows. Interpretation of photographs (March 1985 and April 1988) provides reference data for evaluation of results with three Landsat TM images of coastal North Carolina. Agreement of the Landsat classification with reference data was as high as 72.6% for a June 1992 image. Despite limited development of coastal North Carolina, seagrasses closely associated with the mainland are relatively low in abundance and are restricted to shallower water than seagrasses nearer the uninhabited barrier islands. Published by Elsevier Science B.V. C1 DENISON UNIV, GRANVILLE, OH 43023 USA. RP Ferguson, RL (reprint author), NOAA, NATL MARINE FISHERIES SERV, SE FISHERIES SCI CTR, BEAUFORT LAB, 101 PIVERS ISL RD, BEAUFORT, NC 28516 USA. NR 47 TC 51 Z9 53 U1 1 U2 23 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3770 J9 AQUAT BOT JI Aquat. Bot. PD OCT PY 1997 VL 58 IS 3-4 BP 241 EP 258 DI 10.1016/S0304-3770(97)00038-7 PG 18 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA YL246 UT WOS:A1997YL24600004 ER PT J AU Porter, DE Edwards, D Scott, G Jones, B Street, WS AF Porter, DE Edwards, D Scott, G Jones, B Street, WS TI Assessing the impacts of anthropogenic and physiographic influences on grass shrimp in localized salt-marsh estuaries SO AQUATIC BOTANY LA English DT Article DE geographic information systems; estuaries; critical habitat; kriging; resource management; spatial modeling ID SOUTH-CAROLINA; MODELS; GIS AB The complexity and severity of ecological impacts associated with coastal development demand that resource managers explore new spatial analytical techniques combined with multidisciplinary scientific expertise for proactive coastal zone management. Arising from these environmental concerns and the identified need for adequate databases and integrated models, a long-term study of the impacts of urbanization on localized estuaries of the South eastern United States was initiated in 1990. A goal of this study was to examine the role of Geographic Information Processing (GIP) to integrate data and scientific expertise for the identification, assessment, and modeling of anthropogenic and physiographic relationships within estuaries. This goal is being achieved through the implementation and utilization of a multi-agency Geographic Information System (GIS) and the development and validation of spatially explicit models. This work presents spatial modeling efforts that incorporate land use and land cover characteristics with fisheries data to assess and predict the impacts of anthropogenic and natural influences on key species that inhabit critical estuarine wetlands and streams. A spatial assessment of two small, high-salinity estuaries suggests that upland development adjacent to critical estuarine habitat limits the population size and distribution of adult and larval grass shrimp (Palaemonetes pugio (Holthuis)). Modeled spatial distributions of adult populations suggest the existence of estuarine 'deserts' - wetlands and stream reaches adjacent to commercial and residential land use void of natant fauna. This paper's approach is being developed for coastal resource managers to predict the impact of proposed landscape modifications prior to occurrence of changes. (C) 1997 Elsevier Science B.V. C1 UNIV S CAROLINA, MARINE SCI PROGRAM, COLUMBIA, SC 29208 USA. UNIV S CAROLINA, DEPT STAT, COLUMBIA, SC 29208 USA. NOAA, NATL MARINE FISHERIES SERV, SE FISHERIES SCI CTR, CHARLESTON LAB, CHARLESTON, SC 29422 USA. RP Porter, DE (reprint author), UNIV S CAROLINA, BELLE W BARUCH INST MARINE BIOL & COASTAL RES, COLUMBIA, SC 29208 USA. NR 35 TC 12 Z9 13 U1 2 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3770 EI 1879-1522 J9 AQUAT BOT JI Aquat. Bot. PD OCT PY 1997 VL 58 IS 3-4 BP 289 EP 306 DI 10.1016/S0304-3770(97)00041-7 PG 18 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA YL246 UT WOS:A1997YL24600007 ER PT J AU Dove, JB Wilms, J Begelman, MC AF Dove, JB Wilms, J Begelman, MC TI Self-consistent thermal accretion disk corona models for compact objects .1. Properties of the corona and the spectrum of escaping radiation SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; radiation mechanisms, nonthermal; radiative transfer; stars, coronae ID ACTIVE GALACTIC NUCLEI; PHOTOIONIZATION CROSS-SECTIONS; X-RAY REFLECTION; BLACK-HOLES; CYGNUS X-1; PAIR PRODUCTION; COMPTON REFLECTION; SEYFERT-GALAXIES; COLD MATTER; EMISSION AB We present the properties of accretion disk corona (ADC) models in which the radiation field, the temperature, and the total opacity of the corona are determined self-consistently. We use a nonlinear Monte Carlo code to perform the calculations. As an example, we discuss models in which the corona is situated above and below a cold accretion disk with a plane-parallel (slab) geometry, similar to the model of Haardt & Maraschi. By Comptonizing the soft radiation emitted by the accretion disk, the corona is responsible for producing the high-energy component of the escaping radiation. Our models include the reprocessing of radiation in the accretion disk. Here the photons either are Compton-reflected or photoabsorbed, giving rise to fluorescent line emission and thermal emission. The self-consistent coronal temperature is determined by balancing heating (due to viscous energy dissipation) with Compton cooling, determined using the fully relativistic, angle-dependent cross sections. The total opacity is found by balancing pair productions with annihilations. We find that, for a disk temperature kT(BB) less than or similar to 200 eV, these coronae are unable to have a self-consistent temperature higher than similar to 140 keV if the total optical depth is greater than or similar to 0.2, regardless of the compactness parameter of the corona and the seed opacity. This limitation corresponds to the angle-averaged spectrum of escaping radiation having a photon index greater than or similar to 1.8 within the 5-30 keV band. Finally, all models that have reprocessing features also predict a large thermal excess at lower energies. These constraints make explaining the X-ray spectra of persistent black hole candidates with ADC models very problematic. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV COLORADO,DEPT ASTROPHYS PLANETARY & ATMOSPHER SCI,BOULDER,CO 80309. INST ASTRON & ASTROPHYS,ABT ASTRON,D-72076 TUBINGEN,GERMANY. RP Dove, JB (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,CAMPUS BOX 440,BOULDER,CO 80309, USA. RI Wilms, Joern/C-8116-2013 OI Wilms, Joern/0000-0003-2065-5410 NR 62 TC 54 Z9 55 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 1 PY 1997 VL 487 IS 2 BP 747 EP 758 DI 10.1086/304632 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YA040 UT WOS:A1997YA04000026 ER PT J AU Dove, JB Wilms, J Maisack, M Begelman, MC AF Dove, JB Wilms, J Maisack, M Begelman, MC TI Self-consistent thermal accretion disk corona models for compact objects .2. Application to Cygnus X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; radiation mechanisms, nonthermal; radiative transfer; stars, coronae; X-rays, stars ID ADVECTION-DOMINATED ACCRETION; X-RAY-SPECTRUM; HEXE OBSERVATIONS; BLACK-HOLES; IRON LINE; COMPTONIZATION; PARAMETERS; EMISSION; STARS AB We apply our self-consistent accretion disk corona (ADC) model, with two different geometries, to the broadband X-ray spectrum of the black hole candidate Cygnus X-1. As shown in a companion paper, models in which the Comptonizing medium is a slab surrounding the cold accretion disk cannot have a temperature higher than about 140 keV for optical depths greater than 0.2, resulting in spectra that are much softer than the observed 10-30 keV spectrum of Cyg X-1. In addition, the slab-geometry models predict a substantial ''soft excess'' at low energies, a feature not observed for Cyg X-1, and Fe K alpha fluorescence lines that are stronger than observed. Previous Comptonization models in the literature have invoked a slab geometry with optical depth tau(T) greater than or similar to 0.3 and coronal temperature T-c similar to 150 keV, but they are not self-consistent. Therefore, ADC models with a slab geometry are not appropriate for explaining the X-ray spectrum of Cyg X-1. Models with a spherical corona and an exterior disk, however, predict much higher self-consistent coronal temperatures than the slab-geometry models. The higher coronal temperatures are due to the lower amount of reprocessing of coronal radiation in the accretion disk, giving rise to a lower Compton cooling rate. Therefore, for the sphere-plus-disk geometry, the predicted spectrum can be hard enough to describe the observed X-ray continuum of Cyg X-1 while predicting Fe fluorescence lines having an equivalent width of similar to 40 eV. Our best-fit parameter values for the sphere-plus-disk geometry are tau(T) approximate to 1.5 and T-c approximate to 90 keV. C1 NATL INST STAND & TECHNOL, BOULDER, CO 80309 USA. UNIV COLORADO, DEPT ASTROPHYS PLANETARY & ATMOSPHER SCI, BOULDER, CO 80309 USA. INST ASTRON & ASTROPHYS, ABT ASTRON, D-72076 TUBINGEN, GERMANY. RP Dove, JB (reprint author), UNIV COLORADO, JOINT INST LAB ASTROPHYS, CAMPUS BOX 440, BOULDER, CO 80309 USA. RI Wilms, Joern/C-8116-2013 OI Wilms, Joern/0000-0003-2065-5410 NR 47 TC 96 Z9 96 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 1 PY 1997 VL 487 IS 2 BP 759 EP 768 DI 10.1086/304647 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YA040 UT WOS:A1997YA04000027 ER PT J AU Roitberg, AE AF Roitberg, AE TI A molecular dynamics study of Fe2S2 putidaredoxin: Multiple conformations of the C-terminal region SO BIOPHYSICAL JOURNAL LA English DT Article ID NORMAL-MODE ANALYSIS; CYTOCHROME P450(CAM); ELECTRON-TRANSFER; PROTEIN; IDENTIFICATION; FIELD; CYTOCHROME-P-450(CAM); DEHALOGENATION; HYDROXYLATION; OPTIMIZATION AB Putidaredoxin (Pdx) plays an essential role as an electron donor and effector in the biochemical cycle involving cytochrome P450cam. Only recently has an NMR-derived structure for this protein been published, but because of the presence of a paramagnetic Fe2S2 center, the NMR assignment could not be completed for residues within a region of 8 Angstrom around the active site. That region was modeled by homology with a related protein. The structural refinement for those experiments was done in vacuum, without the use of electrostatic terms in the force field. The present manuscript will describe and discuss a series of long-time, unrestrained, solution molecular dynamic runs for this system. Results will be presented that construct a molecular-level picture that rationalizes experimental results concerning the conformation and mobility of the C-terminal residue Trp(106). At least two different conformers are found for this residue during the simulations. The time scale for interconversion between them is found to be in the subnanosecond regime. The results presented here open the possibility for studying binding and electron transfer between Pdx and P450cam, in a framework that allows for dynamical information to be used during the computational process, instead of the single structures deposited on the protein data base. RP Roitberg, AE (reprint author), NIST, BIOPROC ENGN GRP, BLDG 222-A353, GAITHERSBURG, MD 20899 USA. RI Roitberg, Adrian/A-2378-2009 NR 45 TC 8 Z9 8 U1 0 U2 2 PU CELL PRESS PI CAMBRIDGE PA 600 TECHNOLOGY SQUARE, 5TH FLOOR, CAMBRIDGE, MA 02139 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD OCT PY 1997 VL 73 IS 4 BP 2138 EP 2148 PG 11 WC Biophysics SC Biophysics GA XY955 UT WOS:A1997XY95500043 PM 9336209 ER PT J AU Schwarz, FP Inesi, G AF Schwarz, FP Inesi, G TI Entropic drive in the sarcoplasmic reticulum ATPase interaction with Mg2+ and Pi SO BIOPHYSICAL JOURNAL LA English DT Article ID ADENOSINE-TRIPHOSPHATASE; ACTIVE-TRANSPORT; CALCIUM-ATPASE; SPIN-LABEL; PHOSPHORYLATION; MEMBRANES; BINDING; ORTHOPHOSPHATE; KINETICS; CHAINS AB Thermodynamic quantities for the binding of Mg2+ (in the presence of Ca2+) and Pi (in the presence of Mg2+ and absence of Ca2+) to sarcoplasmic reticulum ATPase were determined from isothermal titration calorimetry measurements at 25 degrees C. Mg2+ and Pi are involved in reversal of the ATPase hydrolytic reaction, and their interactions with the ATPase are conveniently studied under equilibrium conditions. We found that the Mg2+ binding reaction is endothermic with a binding constant (K-b) = 142 +/- 4 M-1, a binding enthalpy of 180 +/- 3 kJ mol(-1), and an entropy contribution (T Delta S-b) = 192 +/- 3 kJ mol(-1). Similarly, Pi binding is also an endothermic reaction with K-b = 167 +/- 17 M-1, Delta H-b = 65.3 +/- 5.4 kJ mol(-1), and T Delta S-b = 77.9 +/- 5.4 kJ mol(-1). Our measurements demonstrate that the ATPase can absorb heat from the environment upon ligand binding, and emphasize the important role of entropic mechanisms in energy transduction by this enzyme. C1 UNIV MARYLAND,SCH MED,DEPT BIOCHEM & MOL BIOL,BALTIMORE,MD 21201. NIST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NR 26 TC 3 Z9 4 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 OCT PY 1997 VL 73 IS 4 BP 2179 EP 2182 PG 4 WC Biophysics SC Biophysics GA XY955 UT WOS:A1997XY95500048 PM 9336214 ER PT J AU Juang, HMH Hong, SY Kanamitsu, M AF Juang, HMH Hong, SY Kanamitsu, M TI The NCEP regional spectral model: An update SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID FORECAST SYSTEM; NMC; PREDICTION AB The National Centers for Environmental Prediction (NCEP)/Environmental Modeling Center regional spectral model (RSM) has been improved in several aspects since Juang and Kanamitsu. The major improvements of RSM are its efficiency and functionality. The change of the map factor in the semi-implicit scheme from a mean value to maximal value over the regional domain, the relaxation of the lateral boundary from explicit method to implicit method (or simple blending), and the local diffusion over areas of strong wind allowed the doubling of the model computational time step. The model physics was upgraded with the improvements in the operational global spectral model (GSM) and with an additional explicit cloud scheme. An option to run in either hydrostatic or nonhydrostatic mode has been introduced. Another option to run on a GRAY machine or on a workstation has been fully tested. The nesting process has been changed to provide the capability of nesting into a coarse-resolution RSM, besides the GSM, in a one-way fashion. Thus, multinesting becomes possible, even with different map projections. Regional data assimilation with a gridpoint version of statistical interpolation and the three-dimensional variational method on sigma surfaces has been incorporated. All the output has been encoded in GRIB format, so it can be read on different machines. The authors have tested the improved functionalities of the RSM over a broad range of applications, at resolutions between 80 and 10 km. The daily routine experimental forecasts over North America have acceptable performance. Because the perturbation method, used in the RSM, results in smaller computational error than the full field method, and because the consistency between the GSM and RSM allows for a better treatment of the lateral boundary, the RSM could be used to enhance the reanalysis and regional climate simulations that have long-range integrations. The RSM is also used in the regional ensemble experiments at NCEP. The model was also applied in case studies, such as the case of PYREX in the regional COMPARE project. Several institutions both in the United States and overseas started using the RSM, mostly for regional short-range forecast and climate modeling studies. The RSM has been scheduled to implement into operations at NCEP to possibly enhance the guidance on aviation and on daily weather forecast over Hawaii. The current version of the RSM is available to any institution requesting from the director of NCEP. C1 NATL CTR ENVIRONM PREDICT,NATL RES COUNCIL,CAMP SPRINGS,MD 20746. NCEP,CLIMATE PREDICT CTR,CAMP SPRINGS,MD 20746. RP Juang, HMH (reprint author), NCEP,EMC,SAIC,GSC,WORLD WEATHER BLDG,ROOM 209,CAMP SPRINGS,MD 20746, USA. RI Hong, Song-You/I-3824-2012 NR 40 TC 187 Z9 191 U1 0 U2 6 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 OCT PY 1997 VL 78 IS 10 BP 2125 EP 2143 DI 10.1175/1520-0477(1997)078<2125:TNRSMA>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YE028 UT WOS:A1997YE02800002 ER PT J AU Brooks, HE Witt, A Eilts, MD AF Brooks, HE Witt, A Eilts, MD TI Verification of public weather forecasts available via the media SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID GENERAL FRAMEWORK AB The question of who is the ''best'' forecaster in a particular media market is one that the public frequently asks. The authors have collected approximately one year's forecasts from the National Weather Service and major media presentations for Oklahoma City. Diagnostic verification procedures indicate that the question of best does not have a clear answer. All of the forecast sources have strengths and weaknesses, and it is possible that a user could take information from a variety of sources to come up with a forecast that has more value than any one individual source provides. The analysis provides numerous examples of the utility of a distributions-oriented approach to verification while also providing insight into the problems the public faces in evaluating the array of forecasts presented to them. RP Brooks, HE (reprint author), NATL SEVERE STORMS LAB,ERL,NOAA,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. NR 15 TC 10 Z9 10 U1 0 U2 2 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 OCT PY 1997 VL 78 IS 10 BP 2167 EP 2177 DI 10.1175/1520-0477(1997)078<2167:VOPWFA>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YE028 UT WOS:A1997YE02800005 ER PT J AU Gaffen, DJ Friday, EW Weston, KE Franklin, DB AF Gaffen, DJ Friday, EW Weston, KE Franklin, DB TI The participation of women in meteorology and hydrology in the United States: The US response to a World Meteorological Organization questionnaire SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Letter ID ATMOSPHERIC SCIENCE; MEMBERSHIP C1 NOAA,OFF OCEAN & ATMOSPHER RES,WMO,SILVER SPRING,MD 20910. NOAA,NATL WEATHER SERV,INT ACT OFF,SILVER SPRING,MD 20910. NOAA,NATL WEATHER SERV,FED WOMENS PROGRAM,SILVER SPRING,MD 20910. RP Gaffen, DJ (reprint author), NOAA,AIR RESOURCES LAB,ENVIRONM RES LABS,SILVER SPRING,MD 20910, USA. NR 12 TC 2 Z9 2 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 OCT PY 1997 VL 78 IS 10 BP 2241 EP 2245 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YE028 UT WOS:A1997YE02800011 ER PT J AU Schwing, FB Hayward, TL Sakuma, KM Murphree, T Mascarenas, AS Castillo, SIL Mantyla, AW Cummings, SL Chavez, FP Baltz, K Ainley, DG AF Schwing, FB Hayward, TL Sakuma, KM Murphree, T Mascarenas, AS Castillo, SIL Mantyla, AW Cummings, SL Chavez, FP Baltz, K Ainley, DG TI The state of the California Current, 1996-1997: Mixed signals from the tropics SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article ID EQUATORIAL PACIFIC; CURRENT SYSTEM; EL-NINO; LA-NINA; FLOW AB A large number of data sets from within the California Current region, and the large-scale fields that affect this region, are available for timely assessment of recent environmental conditions in this system, In addition to the long-running quarterly CalCOFI cruises, which featured the initial research cruise of RV Roger Revelle, several surveys off Baja California and central California have provided information on coastal areas adjacent to the present CalCOFI coverage, Conditions throughout the north Pacific and in the California Current are summarized and interpreted for the 1996-97 period. Moderate to weak La Nina conditions have affected the north Pacific since late 1995, But this particular La Nina event displayed an unusual pattern of atmospheric heating in the tropical Pacific, compared to other La Nina events, This may have helped produce a different response over the north Pacific that was, in several important respects, different from a typical La Nina, The most notable differences were in the wind anomalies, which may have contributed to relatively high sea level and warm SSTs offshore of California and Mexico throughout this period. El Nino conditions began to develop in the tropics in early 1997, If this event continues to develop, significant effects on the California Current region can be expected, Variability in coastal conditions is complex, and seems due to the combined effect of local processes and anomalies in large-scale atmospheric and ocean forcing, Coastal indices and time series show no dominant pattern of variability, and the anomalies from their long-term seasonal means were generally not remarkable, Upwelling indices and buoy time series suggest generally high upwelling in the spring and summer of 1996, and unusually high rates in early 1997, In May 1997, upwelling was dramatically reduced along the entire coast, At SIO Pier, SSTs were anomalously warm during the first half of 1996, but closer to the norm in late 1996 and early 1997. In spring 1997, SST and coastal sea-level anomalies began increasing, but it is premature to say this was related to El Nino forcing. What is certain is that warm, El Nino-like conditions have been observed in the region long before the initial development of this latest apparent El Nino. Winter sea-level heights were relatively high due to onshore winds and high fresh-water discharge, and were connected with positive height anomalies extending across the entire north Pacific, a consequence of La Nina. Oceanic circulation patterns observed in 1996-97 were similar to the long-term mean, and have featured relatively high mesoscale activity since early 1996, Salinities in the core of the California Current were noticeably lower than historical climatologies indicate, A strong coastal countercurrent was noted off southern California in August and October 1996 and April 1997, and along the Big Sur coast in June 1996, Warm, saline water that was low in chlorophyll was associated with this now, Despite reasonably high primary production based on chlorophyll concentrations, macrozooplankton biomass remains very low compared to historical levels in the California Current. In recent years, there have also been reduced abundances of juvenile rockfish and seabird populations. High primary production is not clearly related to coastal time series or circulation patterns, and does not appear to be a good predictor of production at higher trophic levels in the California Current. RP Schwing, FB (reprint author), NATL MARINE FISHERIES SERV,PACIFIC FISHERIES ENVIRONM LAB,NOAA,1352 LIGHTHOUSE AVE,PACIFIC GROVE,CA 93950, USA. NR 34 TC 25 Z9 25 U1 0 U2 7 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1997 VL 38 BP 22 EP 47 PG 26 WC Fisheries SC Fisheries GA YK037 UT WOS:A1997YK03700003 ER PT J AU Butler, JL Nishimoto, RN AF Butler, JL Nishimoto, RN TI Growth and cohort dynamics of larval Pacific hake (Merluccius productus) SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article; Proceedings Paper CT 1996 Hake Symposium of the CALCOFI Conference CY OCT 30-31, 1996 CL ASILOMAR, CA ID SIZE-SELECTIVE MORTALITY; COD GADUS-MORHUA; MARINE FISH LARVAE; EARLY LIFE-HISTORY; NORTHERN ANCHOVY; PREDATION; SURVIVAL; MODEL; EGGS; GULF AB Size-specific mortality rates and stage-based models predict that fast-growing fish larvae experience lower mortality than slow-growing larvae. We provide empirical evidence that supports this hypothesis, by comparing otolith size-at-age of young larval Pacific hake (Merluccius productus) with back-calculated otolith size-at-age from older larvae collected about 45 days later. The mean back-calculated size-at-age of the larvae surviving beyond 45 days was greater than the average population growth rate of younger larvae sampled earlier. Thus hake larvae with slow growth rates appear to have suffered higher mortality than larvae with faster growth rates. RP Butler, JL (reprint author), NATL MARINE FISHERIES SERV, SW FISHERIES SCI CTR, POB 271, LA JOLLA, CA 92038 USA. NR 43 TC 22 Z9 22 U1 1 U2 3 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 USA SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1997 VL 38 BP 63 EP 68 PG 6 WC Fisheries SC Fisheries GA YK037 UT WOS:A1997YK03700006 ER PT J AU Dorn, MW AF Dorn, MW TI Mesoscale fishing patterns of factory trawlers in the Pacific hake (Merluccius productus) fishery SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article; Proceedings Paper CT 1996 Hake Symposium of the CALCOFI Conference CY OCT 30-31, 1996 CL ASILOMAR, CA ID DYNAMICS; VARIABILITY; CALIFORNIA; REGRESSION; ABUNDANCE; MOVEMENT; BEHAVIOR; SALMON; MODELS AB During 1991-95, up to 60% of the annual catch of Pacific hake (Merluccius productus) in the U.S. management zone was harvested by a U.S.-based fleet of factory trawlers. Optimal foraging theory was used to motivate a statistical analysis of movement patterns of these vessels. This study focused on the mesoscale characteristics of the environment (5-50 km), and vessel movement at these spatial scales. Geostatistical analyses of hake densities derived from the 1992 and 1995 National Marine Fisheries Service assessment surveys with quantitative echo-sounding techniques showed that strong spatial correlations of hake density do not extend beyond similar to 25-35 km. The range of Pacific hake spatial correlation suggests an association with mesoscale oceanographic features whose characteristic scale in the California Current system is determined by the Rossby radius of deformation (similar to 25 km in mid-latitudes off the West Coast). The foraging patterns of factory trawlers can be described as a series of moves between trawling locations. The distance between successive hauls depends on whether the vessel continues fishing within a local area of high fish density, or moves to a different area. Generalized additive models (GAM) were used to examine influence of the catch rates of prior hauls on the distance between successive hauls. The GAM models suggested that deviations from the expected catch rate influence the decision to move from a local foraging area, as expected from optimization models of animal foraging. These decisions appeared to be based on relatively short time frames, such that information from only the most recent one or two hauls in the area is used. In addition, results indicated that the presence of other fishing vessels operating nearby reduces the probability that a vessel will leave an area. RP Dorn, MW (reprint author), NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,7600 SAND POINT WAY NE,BIN C15700,SEATTLE,WA 98115, USA. NR 40 TC 7 Z9 7 U1 0 U2 0 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1997 VL 38 BP 77 EP 89 PG 13 WC Fisheries SC Fisheries GA YK037 UT WOS:A1997YK03700008 ER PT J AU Lo, NCH Griffith, D Hunter, JR AF Lo, NCH Griffith, D Hunter, JR TI Using a restricted adaptive cluster sampling to estimate Pacific hake larval abundance SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article; Proceedings Paper CT 1996 Hake Symposium of the CALCOFI Conference CY OCT 30-31, 1996 CL ASILOMAR, CA ID MERLUCCIUS-PRODUCTUS; BIOLOGY AB In adaptive sampling the procedure for selecting sample sites and allocating effort depends on data collected during the survey. From March 9 to 27, 1995, stratified adaptive sampling was used to survey Pacific hake larvae because the spatial distribution of the larvae is highly patchy and because adaptive sampling is an efficient means of surveying such a population. The survey, conducted between Los Angeles and San Francisco and covering an area of 202,115 km(2) (59,540 n mi(2)), was designed to test the feasibility of adaptive sampling. Because of limited survey time, we used a restricted design imposing a maximum number of stations in each stratum. A stratified, two-stage cluster Horvitz-Thompson (HT) estimator and a simple stratified (SS) sample mean were used to determine mean catch per tow The variance of the HT estimate included the variance resulting from subsampling within a cluster and was high. The mean density from SS sampling was biased downward, but its variance was a 2-fold reduction over what it would have been if the same number of samples had been allocated proportional to the area size within strata. Nonetheless, our adaptive sampling was relatively easy to implement, and it provided biological information within patches. RP Lo, NCH (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,NOAA,POB 271,LA JOLLA,CA 92038, USA. NR 26 TC 32 Z9 35 U1 0 U2 1 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1997 VL 38 BP 103 EP 113 PG 11 WC Fisheries SC Fisheries GA YK037 UT WOS:A1997YK03700010 ER PT J AU Moser, HG Lo, NCH Smith, PE AF Moser, HG Lo, NCH Smith, PE TI Vertical distribution of Pacific hake eggs in relation to stage of development and temperature SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article; Proceedings Paper CT 1996 Hake Symposium of the CALCOFI Conference CY OCT 30-31, 1996 CL ASILOMAR, CA ID FECUNDITY REDUCTION METHOD; EARLY-LIFE-HISTORY; BIOMASS ESTIMATION; MERLUCCIUS-PRODUCTUS; FISH BIOMASS; STOCK AB The vertical distribution of eggs of Pacific hake (Merluccius productus) was determined from 27 MOCNESS samples taken on cruises off southern and central California in March 1995 and February 1996. In 1995, nine depth strata (0-25, 25-50, 50-75, 75-100, 100-125, 125-150, 150-200, 200-250, and 250-300 m) were sampled. In 1996, nine 25-m depth strata were sampled down to 225 m. In 1995 Pacific hake eggs were taken in all strata down to 250-300 m; most of the eggs were found between 50 and 150 m, with the highest densities in the 50-75- and 75-100-m strata. Average temperatures for developing Pacific hake eggs were estimated to be 10.2 degrees-11.3 degrees C. Early-stage eggs were generally deeper in the water column than later-stage eggs. Most early-stage eggs were found between 75 and 150 m, with highest densities in the 125-150-m stratum. Tn contrast, mid-and late-stage eggs were most dense m the 50-75- and 75-100-m strata. Early-stage eggs were taken primarily in tows between 2200 and 0600 hrs, suggesting diel periodicity in spawning. On the 1996 cruise hake eggs had a slightly shallower distribution compared with 1995, and there was more overlap in vertical distribution between stages. Methods are given for separating Pacific hake eggs from similar eggs of other species, and criteria are described for staging Pacific hake eggs. RP Moser, HG (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,POB 271,LA JOLLA,CA 92038, USA. NR 17 TC 6 Z9 7 U1 0 U2 0 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1997 VL 38 BP 120 EP 126 PG 7 WC Fisheries SC Fisheries GA YK037 UT WOS:A1997YK03700012 ER PT J AU Sakuma, KM Ralston, S AF Sakuma, KM Ralston, S TI Vertical and horizontal distribution of juvenile Pacific whiting (Merluccius productus) in relation to hydrography off California SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article; Proceedings Paper CT 1996 Hake Symposium of the CALCOFI Conference CY OCT 30-31, 1996 CL ASILOMAR, CA ID THERAGRA-CHALCOGRAMMA; WALLEYE POLLOCK; LIFE-HISTORY; HAKE; RECRUITMENT; BIOLOGY; LARVAE; FISHES AB The vertical and horizontal distributional patterns of young-of-the-year juvenile Pacific whiting, Merluccius productus, collected during midwater trawl surveys off California from mid-May through mid-June 1986-95 were examined. Comparison of 1992 MOCNESS tows and depth-stratified midwater trawls indicated that although larvae were most abundant below the mixed layer, juveniles were most abundant in the upper mixed layer. Abundance estimates from the midwater trawl surveys varied from year to year. Large numbers were consistently observed in the Monterey Bay area. The least-squared mean catch per year from a sampling stratum offshore of Monterey Bay was significantly correlated with recruitment to the commercial fishery two years later, suggesting that midwater trawl surveys could provide useful fishery-independent forecasts of year-class strength. Information collected with CTD recorders in 1987-95 indicated that juveniles were significantly less abundant in upwelled water than in non-upwelled water. This could be attributed to advection away from upwelling fronts, a behavioral response to avoid upwelled water, or a general offshore distributional pattern, irrespective of upwelling events. Plots of juvenile abundances and density (sigma(t)) contours showed substantial catches nearshore during periods of upwelling relaxation, whereas nearshore abundances were greatly reduced during strong upwelling events. RP Sakuma, KM (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,TIBURON LAB,3150 PARADISE DR,TIBURON,CA 94920, USA. NR 36 TC 15 Z9 15 U1 0 U2 0 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1997 VL 38 BP 137 EP 146 PG 10 WC Fisheries SC Fisheries GA YK037 UT WOS:A1997YK03700014 ER PT J AU McKinnell, S Pella, JJ Dahlberg, ML AF McKinnell, S Pella, JJ Dahlberg, ML TI Population-specific aggregations of steelhead trout (Oncorhynchus mykiss) in the North Pacific Ocean SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID SALMO-GAIRDNERI; BRITISH-COLUMBIA; SIZE AB The distribution of North American hatchery-origin steelhead (Oncorhynchus mykiss) in the North Pacific Ocean varied by age and hatchery location. Columbia River steelhead were more abundant south of the Aleutian Islands at an earlier age than steelhead from the Georgia Basin (Georgia Strait, Puget Sound, and waters connecting with the open Pacific). Between 1984 and 1989, there were eight independent and coincident recoveries of coded-wire-tagged steelhead, where individuals released from hatcheries as juveniles at similar times and locations were recovered together on the high seas up to 3 years later. A statistical test was developed to determine whether these coincident recoveries should be expected if individual steelhead within populations travelled in the North Pacific in an uncoordinated manner. The overall test suggested that some tagged steelhead populations travelled together in a significantly (P < 0.05) coordinated manner on the high seas. C1 Pacific Biol Stn, Sci Branch, Dept Fisheries & Oceans, Nanaimo, BC V9R 5K6, Canada. Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP McKinnell, S (reprint author), Pacific Biol Stn, Sci Branch, Dept Fisheries & Oceans, Hammond Bay Rd, Nanaimo, BC V9R 5K6, Canada. NR 36 TC 22 Z9 22 U1 0 U2 3 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD OCT PY 1997 VL 54 IS 10 BP 2368 EP 2376 DI 10.1139/cjfas-54-10-2368 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA YR664 UT WOS:000071517900014 ER PT J AU Ferraris, CF Garboczi, EJ Davis, FL Clifton, JR AF Ferraris, CF Garboczi, EJ Davis, FL Clifton, JR TI The effect of stress relaxation, self-desiccation, and water absorption on the alkali-silica reaction in low water/cement ratio mortars SO CEMENT AND CONCRETE RESEARCH LA English DT Article; Proceedings Paper CT MRS Symposium HH on Structure-Property Relationships in Hardened Cement Pastes and Composites CY DEC 02-06, 1996 CL BOSTON, MA SP Mat Res Soc ID CONCRETE AB A device has been designed and tested for measuring the stress caused by the alkali-silica reaction (ASR) in mortars. Specimens were placed in a frame equipped with a load cell, allowing us to approximately fix the strain at zero and measure the total stress generated over time. The specimens and the frame were immersed in a 1-N NaOH solution at 50 degrees C. Even without ASR, the specimens expanded due to water absorption that relieves the shrinkage caused by self-desiccation. In addition, applied stresses, as well as stresses that were set up in the sample by expansion caused by ASR and/or water absorption, were subject to stress relaxation. By using companion samples having nonreactive aggregates, we were able to distinguish the stress caused by ASR from that caused by water absorption-driven expansion. The effects of stress relaxation could not be removed without further experimentation and theoretical analysis. (C) 1997 Elsevier Science Ltd. RP Ferraris, CF (reprint author), NATL INST STAND & TECHNOL,BLDG MAT DIV 226B350,GAITHERSBURG,MD 20899, USA. NR 18 TC 3 Z9 3 U1 3 U2 4 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 OCT PY 1997 VL 27 IS 10 BP 1553 EP 1560 DI 10.1016/S0008-8846(97)00171-3 PG 8 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA YH929 UT WOS:A1997YH92900010 ER PT J AU Neubauer, CM Jennings, HM Garboczi, EJ AF Neubauer, CM Jennings, HM Garboczi, EJ TI Mapping drying shrinkage deformations in cement-based materials SO CEMENT AND CONCRETE RESEARCH LA English DT Article; Proceedings Paper CT MRS Symposium HH on Structure-Property Relationships in Hardened Cement Pastes and Composites CY DEC 02-06, 1996 CL BOSTON, MA SP Mat Res Soc AB A new technique for mapping the deformations in a digital image of microstructure is presented. This technique works on any set of two digital images of the same area taken before and after deformations are generated. Results for cement paste show that the deformations are distributed as large compactions separated by crack-like rarefactions. The rarefactions may represent the precursor to microcracking. The results suggest that macro-scale deformation is the result of a competition between expanding and contracting parts of the matrix. Individual microdeformations can then be much higher in magnitude than average macrodeformations. A single shrinkage value like the average macrodeformation does not, therefore, adequately represent the microstructural processes occurring during drying shrinkage. (C) 1997 Elsevier Science Ltd. C1 NORTHWESTERN UNIV,DEPT MAT SCI,EVANSTON,IL 60208. NORTHWESTERN UNIV,DEPT CIVIL ENGN,EVANSTON,IL 60208. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RI Jennings, Hamlin/B-7006-2009 NR 14 TC 11 Z9 11 U1 0 U2 5 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 OCT PY 1997 VL 27 IS 10 BP 1603 EP 1612 DI 10.1016/S0008-8846(97)00217-2 PG 10 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA YH929 UT WOS:A1997YH92900015 ER PT J AU Reid, GC AF Reid, GC TI Solar forcing of global climate change since the mid-17th century SO CLIMATIC CHANGE LA English DT Article ID IRRADIANCE VARIATIONS; SURFACE-TEMPERATURE; MAUNDER MINIMUM; ICE-AGE; LUMINOSITY; CYCLE; MODEL; RECONSTRUCTION; VARIABILITY; NORTHERN AB Spacecraft measurements of the sun's total irradiance since 1980 have revealed a long-term variation that is roughly in phase with the 11-year solar cycle. Its origin is uncertain, but may be related to the overall level of solar magnetic activity as well as to the concurrent activity on the visible disk. A low-pass Gaussian filtered time series of the annual sunspot number has been developed as a suitable proxy for solar magnetic activity that contains a long-term component related to the average level of activity as well as a short-term component related to the current phase of the I I-year cycle. This time series is also assumed to be a proxy for solar total irradiance, and the irradiance is reconstructed for the period since 1617 based on the estimate from climatic evidence that global temperatures during the Maunder Minimum of solar activity, which coincided with one of the coldest periods of the Little Ice Age, were about 1 degrees C colder than modem temperatures. This irradiance variation is used as the variable radiative forcing function in a one-dimensional ocean-climate model, leading to a reconstruction of global temperatures over the same period, and to a suggestion that solar forcing and anthropogenic greenhouse-gas forcing made roughly equal contributions to the rise in global temperature that took place between 1900 and 1955. The importance of solar variability as a factor in climate change over the last few decades may have been underestimated in recent studies. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,CIRES,BOULDER,CO 80309. RP Reid, GC (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 46 TC 63 Z9 67 U1 0 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD OCT PY 1997 VL 37 IS 2 BP 391 EP 405 DI 10.1023/A:1005307009726 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XZ628 UT WOS:A1997XZ62800006 ER PT J AU Kim, J Sunder, SS AF Kim, J Sunder, SS TI Statistical effects on the evolution of compliance and compressive fracture stress of ice SO COLD REGIONS SCIENCE AND TECHNOLOGY LA English DT Article DE microcrack; fracture stress; evolution of compliance; statistical distribution ID ANISOTROPY; FAILURE AB The large scatter in the experimental data of ice is partly due to the difference in the microstructure. The micromechanical damage model of Wu and Shyam Sunder [Wu, M.S., Shyam Sunder, S., 1992. Elastic anisotropy and micro-damage processes in polycrystalline ice, Part I. Theoretical formulation. Int. J. Fracture 55, 223-243.] is used to investigate the statistical effects caused by the randomness in the microstructural properties such as: microcrack length, grain size and crystallographic orientation, Probability density functions are constructed from experimental data to represent the distribution of parameters, and are used to predict the evolution of the compliance. A probability theory is used to formulate the probabilistic distribution of the failure stress and the compliance caused by the distribution of the underlying microstructural parameters. The 10 to 90th percentiles of the failure stress obtained from the model analysis reasonably match with the scatter in the given experimental data. (C) 1997 Elsevier Science B.V. C1 Samsung Engn & Construct, Inst Technol, Gyung Gi Do, South Korea. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Kim, J (reprint author), Samsung Engn & Construct, Inst Technol, San 25, Gyung Gi Do, South Korea. NR 15 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-232X J9 COLD REG SCI TECHNOL JI Cold Reg. Sci. Tech. PD OCT PY 1997 VL 26 IS 2 BP 137 EP 152 DI 10.1016/S0165-232X(97)00013-X PG 16 WC Engineering, Environmental; Engineering, Civil; Geosciences, Multidisciplinary SC Engineering; Geology GA YN621 UT WOS:000071188300003 ER PT J AU Jones, CA Pease, KA AF Jones, CA Pease, KA TI Restoration-based compensation measures in natural resource liability statutes SO CONTEMPORARY ECONOMIC POLICY LA English DT Article ID STATED PREFERENCE METHODS; CONJOINT-ANALYSIS; VALUATION AB In the past two decades, the U.S. Congress has passed several major environmental statutes that designate natural resource management agencies as trustees of the resources on behalf of the public and that allow the trustees to recover damages for injuries to public resources from releases of hazardous substances and discharges of oil. The standard measure of damages in the various statutes is the cost of restoring the resources to baseline conditions (''primary restoration'') plus the interim loss in value from the time of the incident until full recovery from the injuries. However trustees are allowed to spend their damage recoveries only on enhancing or creating (''restoring, rehabilitating, replacing or acquiring the equivalent of'') natural resources. The statutory restriction on the use of the recoveries has motivated the development of an alternative measure of damages for interim losses-the cost of ''compensatory restoration'' actions providing in-kind compensation-which the National Oceanic and Atmospheric Administration (NOAA) incorporated in its 1996 regulations implementing the natural resource liability provisions of the Oil Pollution Act (OPA). This analysis first identifies the statutory measure of damages and the traditional framing of damages for interim losses (monetary compensation). It then defines an alternative utility-theoretic measure of resource compensation and identifies alternative methods of implementation. C1 NOAA,OFF GEN COUNSEL,LONG BEACH,CA. RP Jones, CA (reprint author), NOAA,DAMAGE ASSESSMENT CTR,RESOURCE VALUAT BRANCH,SILVER SPRING,MD 20910, USA. NR 26 TC 38 Z9 42 U1 0 U2 7 PU WESTERN ECONOMIC ASSOC INT PI HUNTINGTON BEACH PA 7400 CENTER AVE SUITE 109, HUNTINGTON BEACH, CA 92647-3039 SN 1074-3529 J9 CONTEMP ECON POLICY JI Contemp. Econ. Policy PD OCT PY 1997 VL 15 IS 4 BP 111 EP 122 PG 12 WC Economics; Public Administration SC Business & Economics; Public Administration GA YC467 UT WOS:A1997YC46700011 ER PT J AU Garrett, ES dosSantos, CL Jahncke, ML AF Garrett, ES dosSantos, CL Jahncke, ML TI Public, animal, and environmental health implications of aquaculture SO EMERGING INFECTIOUS DISEASES LA English DT Article; Proceedings Paper CT Conference on Emerging Foodborne Pathogens - Implications and Control CY MAR 24-26, 1997 CL ALEXANDRIA, VA SP Int Life Sci Inst, N Amer Tech Comm Food Microbiol, USDA, Ctr Dis Control & Prevention, USFDA, FAO, WHO, Pan Amer Hlth Org, NIDDKD AB Aquaculture is important to the United States and the world's fishery system. Both import and export markets for aquaculture products will expand and increase as research begins to remove physiologic and other animal husbandry barriers. Overfishing of wild stock will necessitate supplementation and replenishment through aquaculture. The aquaculture industry must have a better understanding of the impact of the ''shrouded'' public and animal health issues: technology ignorance, abuse, and neglect. Cross-pollination and cross-training of public health and aquaculture personnel in the effect of public health, animal health, and environmental health on aquaculture are also needed. Future aquaculture development programs require an integrated Gestalt public health approach to ensure that aquaculture does not cause unacceptable risks to public or environmental health and negate the potential economic and nutritional benefits of aquaculture. C1 VIRGINIA TECH,SEAFOOD RES & EXTENS CTR,HAMPTON,VA 23669. NATL SEAFOOD INSPECT LAB,PASCAGOULA,MS. FOOD & AGR ORG UN,ROME,ITALY. NR 23 TC 26 Z9 28 U1 0 U2 8 PU CENTER DISEASE CONTROL PI ATLANTA PA ATLANTA, GA 30333 SN 1080-6040 J9 EMERG INFECT DIS JI Emerg. Infect. Dis PD OCT-DEC PY 1997 VL 3 IS 4 BP 453 EP 457 PG 5 WC Immunology; Infectious Diseases SC Immunology; Infectious Diseases GA YE794 UT WOS:A1997YE79400006 PM 9366596 ER PT J AU Auster, PJ Malatesta, RJ Donaldson, CLS AF Auster, PJ Malatesta, RJ Donaldson, CLS TI Distributional responses to small-scale habitat variability by early juvenile silver hake, Merluccius bilinearis SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE ROV; transect; video; predator avoidance; prey capture ID CONTINENTAL-SHELF; GEORGES-BANK; COD AB Early juvenile (0-year) silver hake, Merluccius bilinearis, occurred at higher densities on bottoms with greater amphipod tube cover at a 55 m deep site in the Middle Atlantic Eight. The size range of individuals at this site was 1.5-5 cm total length. Additional observations at other sites showed that 0-year silver hake only occurred on silt-sand bottom with amphipod tubes at bottom water temperatures of 8.7-11.4 degrees C. This distribution pattern could be the result of either selective settlement into appropriate habitats or differential predation with higher survivorship in more complex habitats. We posit that 0-year silver hake occur in patches of dense amphipod tube cover to avoid visual predators and co-occur with preferred prey (i.e., amphipods and shrimps). C1 SEA EDUC ASSOC,WOODS HOLE,MA 02543. UNIV CONNECTICUT,INST MARINE SCI,GROTON,CT 06340. RP Auster, PJ (reprint author), UNIV CONNECTICUT,NOAA,NATL UNDERSEA RES CTR,GROTON,CT 06340, USA. NR 14 TC 54 Z9 54 U1 0 U2 3 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 OCT PY 1997 VL 50 IS 2 BP 195 EP 200 DI 10.1023/A:1007305628035 PG 6 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA XW489 UT WOS:A1997XW48900008 ER PT J AU Bergin, MH Ogren, JA Schwartz, SE McInnes, LM AF Bergin, MH Ogren, JA Schwartz, SE McInnes, LM TI Evaporation of ammonium nitrate aerosol in a heated nephelometer: Implications for field measurements SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID RELATIVE-HUMIDITY; SIZE; TEMPERATURE; DEPENDENCE AB Ammonium nitrate is a semivolatile aerosol component under typical ambient conditions and thus difficult to measure. In the field, the aersosol scattering coefficient is usually measured with a nephelometer by heating the ambient aerosol to a low reference relative humidity (similar to 40%) in order to measure a light scattering coefficient that is intrinsic to an aerosol rather than dependent on atmospheric relative humidity. In this paper, we examine the decrease in the light scattering coefficient of ammonium nitrate aerosol due to evaporation in a heated nephelometer. Changes in the scattering coefficient of a laboratory-generated ammonium nitrate aerosol are measured as a function of mean residence time and temperature within the nephelometer sample volume. At the same time, the change in the aerosol size distribution due to ammonium nitrate evaporation is directly measured with a laser particle counter. The change in the aerosol size distribution and scattering coefficient is modeled as a function of mean residence time and temperature. Model results for the change in the aerosol scattering coefficient due to evaporation agree with measurements to within 10%. Application of the theory to conditions typical of NOAA field sites suggests that the decrease in the aerosol scattering coefficient due to the evaporation of ammonium nitrate is generally less than 20%. C1 BROOKHAVEN NATL LAB,ENVIRONM CHEM DIV,UPTON,NY 11973. RP Bergin, MH (reprint author), NOAA,CLIMATE MONITORING & DIAGNOST LAB,325 BROADWAY,R-E-CG1,BOULDER,CO 80303, USA. RI Schwartz, Stephen/C-2729-2008; Ogren, John/M-8255-2015 OI Schwartz, Stephen/0000-0001-6288-310X; Ogren, John/0000-0002-7895-9583 NR 22 TC 56 Z9 59 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD OCT PY 1997 VL 31 IS 10 BP 2878 EP 2883 DI 10.1021/es970089h PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XZ787 UT WOS:A1997XZ78700049 ER PT J AU Driscoll, SK Landrum, PF AF Driscoll, SK Landrum, PF TI A comparison of equilibrium partitioning and critical body residue approaches for predicting toxicity of sediment-associated fluoranthene to freshwater amphipods SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE equilibrium partitioning; critical body residue; fluoranthene; sediment; amphipods ID POLYCYCLIC AROMATIC-HYDROCARBONS; ORGANIC-CHEMICALS; QUALITY CRITERIA; HYALELLA-AZTECA; DAPHNIA-MAGNA; TOXICOKINETICS; BURDENS; BIOAVAILABILITY; DIPOREIA; EXPOSURE AB Equilibrium partitioning (EqP) theory, which has been used to develop sediment quality criteria, predicts that the effects of organic compounds in sediments can be assessed by comparison of organic carbon-normalized sediment concentrations and estimated pore-water concentrations to effects determined in water-only exposures. A complementary approach, the critical body residue (CBR) theory, examines actual body burdens in relation to toxic effects. Critical body residue theory predicts that the narcotic effects of nonpolar compounds should be essentially constant for similar organisms, and narcosis should be observed at body burdens of 2 to 8 mu mol/g tissue. This study compares these two approaches for predicting toxicity of the polycyclic aromatic hydrocarbon (PAH) fluoranthene. The freshwater amphipods Hyalella azteca and Diporeia spp. were exposed for up to 30 d to sediment spiked with radiolabeled fluoranthene at concentrations of 0.1 (trace) to 3,940 nmol/g dry weight (=346 mu mol/g organic carbon). Mean survival of Diporeia was generally high (>70%) and not significantly different from that of control animals. This result agrees with EqP predictions, because little mortality was observed for Diporeia in 10-d water-only exposures to fluoranthene in previous studies. After 10-d exposures, mortality of H. azteca was not significantly different from that of controls, even though measured interstitial water concentrations exceeded the previously determined 10-d water-only median lethal concentration (LC50). Equilibrium partitioning overpredicted fluoranthene sediment toxicity in this species. More mortality was observed for H. azteca at later time points, and a 16-d LC50 of 3,550 nmol/g dry weight sediment (291 mu mol/g organic carbon) was determined. A body burden of 1.10 mu mol fluoranthene-equivalents/g wet weight in H. azteca was associated with 50% mortality after 16-d exposures. Body burdens as high as 5.9 mu mol/g wet weight resulted in little mortality in Diporeia. Diporeia, which has limited ability to metabolize fluoranthene and a higher lipid content, appears to be less sensitive than H. azteca, which does metabolize fluoranthene. These results demonstrate that the CBR approach is a useful complement to the EqP approach for the prediction and assessment of toxicity associated with contaminated sediments. C1 NOAA,GREAT LAKES ENVIRONM RES LAB,ANN ARBOR,MI 48105. UNIV MICHIGAN,COOPERAT INST LIMNOL & ECOSYST RES,ANN ARBOR,MI 48109. NR 29 TC 29 Z9 30 U1 3 U2 6 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 OCT PY 1997 VL 16 IS 10 BP 2179 EP 2186 DI 10.1897/1551-5028(1997)016<2179:ACOEPA>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA XZ451 UT WOS:A1997XZ45100027 ER PT J AU DeVries, DA Grimes, CB AF DeVries, DA Grimes, CB TI Spatial and temporal variation in age and growth of king mackerel, Scomberomorus cavalla, 1977-1992 SO FISHERY BULLETIN LA English DT Article ID SOUTHEASTERN UNITED-STATES; SEX-RATIO; SIZE; MEXICO; GULF AB A total of 12,180 king mackerel, Scomberomorus cavalla, collected from 1986 to 1992 from North Carolina to Yucatan, Mexico, and 2,033 collected in 1977 and 1978 from North Carolina to Texas were aged with whole or sectioned sagittal otoliths. Data were analyzed by region-Atlantic Ocean, eastern Gulf of Mexico, and western Gulf-reflecting the currently recognized stocks. Maximum sizes of females aged were 152, 158, and 147 cm FL in the Atlantic, eastern Gulf, and western Gulf, whereas the largest males were 121, 127, and 117 cm FL in those same regions. Maximum ages from the 1986-92 fish were 26, 21, and 26 yr for females and 24, 22, and 23 yr for males in the Atlantic, eastern Gulf, and western Gulf, respectively. Females grew faster and larger than males at every age in each region. A very consistent pattern of greatest growth in the eastern Gulf, intermediate in the western Gulf, and least in the Atlantic was present each year during 1986-92, most noticeably among females. During 1977-78, Atlantic females also had distinctly lower growth than Gulf fish. These consistent regional differences support the current hypothesis that there are three stocks as suggested by previous analyses of other types of data. Within a region and sex, growth was lower in 1971-78 than in 1986-92 in both the Atlantic and eastern Gulf, but higher for western Gulf females. RP DeVries, DA (reprint author), NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,PANAMA CITY LAB,3500 DELWOOD BEACH RD,PANAMA CITY,FL 32408, USA. NR 18 TC 26 Z9 28 U1 2 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 OCT PY 1997 VL 95 IS 4 BP 694 EP 708 PG 15 WC Fisheries SC Fisheries GA YA863 UT WOS:A1997YA86300006 ER PT J AU Johnson, SW Carls, MG Stone, RP Brodersen, CC Rice, SD AF Johnson, SW Carls, MG Stone, RP Brodersen, CC Rice, SD TI Reproductive success of Pacific herring, Clupea pallasi, in Prince William Sound, Alaska, six years after the Exxon Valdez oil spill SO FISHERY BULLETIN LA English DT Article ID HARENGUS-PALLASI AB The Exxon Valdez oil spill occurred just prior to the spring migration of Pacific herring, Clupea pallasi, from offshore feeding grounds to nearshore spawning areas in Prince William Sound PWS), Alaska. Most or all of the life stages of herring in PWS may have been exposed to oil after the March 1989 spill. Delayed impacts from the spill were suspected as one possible cause in the unprecedented crash of the adult herring population in 1993 and stimulated studies to assess reproductive success. In spring 1995, mature herring were collected from four sites in PWS and from three uncontaminated sites in southeast Alaska (SE) to determine if reproductive impairment was evident in PWS herring six years after the spill. Herring were artificially spawned and their eggs were reared in a laboratory until hatching. Observed response parameters included fertilization success, hatching times, hatching success, as well as larval viability, swimming ability and spinal abnormalities. Responses of all year classes combined or those restricted to the same year class did not differ significantly between regions (P>0.50); the best and worst responses generally occurred in the SE. Within each site, response of the 1989 year class (most likely impacted by the oil spill in PWS) generally did not differ significantly from any other year class. To verify macroscopic observations, a subset of larvae from the 1989 year class was also inspected microscopically for yolk and pericardial abnormalities, and yolk volume was measured-but no significant regional differences were observed for any of these morphological categories. Based on the parameters examined in this study, evidence of reproductive impairment of Pacific herring in PWS by the spill was not detected in 1995, and the chances of detecting any oil-related effects against natural background variation appeared to be negligible. RP Johnson, SW (reprint author), NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,AUKE BAY LAB,11305 GLACIER HIGHWAY,JUNEAU,AK 99801, USA. NR 25 TC 6 Z9 6 U1 1 U2 7 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 OCT PY 1997 VL 95 IS 4 BP 748 EP 761 PG 14 WC Fisheries SC Fisheries GA YA863 UT WOS:A1997YA86300010 ER PT J AU Ramon, D Bartoo, N AF Ramon, D Bartoo, N TI The effects of formalin and freezing on ovaries of albacore, Thunnus alalunga SO FISHERY BULLETIN LA English DT Article RP Ramon, D (reprint author), NATL MARINE FISHERIES SERV,NOAA,SW FISHERIES SCI CTR,LA JOLLA,CA 92038, USA. NR 7 TC 6 Z9 6 U1 1 U2 2 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD OCT PY 1997 VL 95 IS 4 BP 869 EP 872 PG 4 WC Fisheries SC Fisheries GA YA863 UT WOS:A1997YA86300021 ER PT J AU Schulz, RW vanderWind, F JanssenDommerholt, C Peute, J Mylonas, CC Zohar, Y Swanson, P Goos, HJT AF Schulz, RW vanderWind, F JanssenDommerholt, C Peute, J Mylonas, CC Zohar, Y Swanson, P Goos, HJT TI Modulation of testicular androgen production in adolescent African catfish (Clarias gariepinus) SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article ID GONADOTROPIN-RELEASING HORMONES; MESSENGER-RIBONUCLEIC-ACID; REPRODUCTIVE-CYCLE; RAINBOW-TROUT; LEYDIG-CELLS; CHORIONIC-GONADOTROPIN; STEROIDOGENIC ENZYMES; PUBERTAL DEVELOPMENT; ONCORHYNCHUS-MYKISS; SALMO-GAIRDNERI AB At 6 months of age the first spermatozoa appear in the testes of the African catfish considered to be adolescent, since the development to adulthood (12 months of age) is accompanied by further morphological and functional differentiation of Leydig cells. There are increasing plasma levels of 11-ketotestosterone (11-KT) and an increasing responsiveness to luteinizing hormone (LH) of testicular androgen secretion in vitro. Whether treatment of adolescent males with key hormones of the brain-pituitary-gonad axis [gonadotropin-releasing hormone (GnRH), LH, and 11-KT] affects the testicular steroidogenic response to a challenge with LM in vitro 7 days later has been investigated. Injection of GnRH (2.5 mu g chicken GnRH-11 per kilogram of body weight), LH (25 mu g/kg), or a high dose of 11-KT (50 mu g/kg) downregulated basal and LH-stimulated testicular androgen secretion to a minimum of 35% of control values. Treatment with LH was, moreover, associated with changes in the ultrastructure of Leydig cell mitochondria which were either swollen and had a less elect-ion-dense matrix or showed an elongated shape, Conversely, a moderate dose of 11-KT (20 mu g/kg) enhanced LH-stimulated, but not basal, androgen secretion in vitro to a maximum of 190% of control values. in view of the generally low LH plasma levels and of the steadily increasing 11-KT plasma levels during puberty, 11-KT may be involved in the up-regulation of the testicular steroidogenic capacity observed during development to full maturity. (C) 1997 Academic Press. C1 UNIV MARYLAND,INST BIOTECHNOL,COLUMBUS CTR,CTR MARINE BIOTECHNOL,BALTIMORE,MD 21202. NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,SEATTLE,WA 98112. RP Schulz, RW (reprint author), UNIV UTRECHT,DEPT EXPT ZOOL,RES GRP COMPARAT ENDOCRINOL,PADUALAAN 8,NL-3584 CH UTRECHT,NETHERLANDS. RI Mylonas, Constantinos/G-9196-2011; Schulz, Rudiger/B-9046-2011 OI Schulz, Rudiger/0000-0001-9115-669X NR 38 TC 9 Z9 9 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0016-6480 J9 GEN COMP ENDOCR JI Gen. Comp. Endocrinol. PD OCT PY 1997 VL 108 IS 1 BP 56 EP 66 DI 10.1006/gcen.1997.6951 PG 11 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA XZ498 UT WOS:A1997XZ49800005 PM 9378274 ER PT J AU Larsen, DA Swanson, P AF Larsen, DA Swanson, P TI Effects of gonadectomy on plasma gonadotropins I and II in coho salmon, Oncorhynchus kisutch SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article ID BETA SUBUNIT GENE; PRECOCIOUS SEXUAL DEVELOPMENT; JUVENILE RAINBOW-TROUT; AMINO-ACID-SEQUENCES; GTH-II; PITUITARY GONADOTROPHS; REPRODUCTIVE-CYCLE; MOLECULAR-CLONING; MASU SALMON; ALPHA-SUBUNIT AB Studies of both salmon and trout have indicated that the levels of gonadotropins, GTH I, and GTH II, in the pituitary and peripheral circulation vary during the reproductive cycle. To evaluate the possible Feedback relationship between the gonads and pituitary GTH secretion, we studied the effects of bilateral gonadectomy on plasma levels of GTH I and GTH II in coho salmon, Oncorhynchus kisutch. During late spermatogenesis in males and late vitellogenesis in females, plasma GTH I levels increased significantly after gonadectomy approximately 6- and 5-fold over presurgery levels at 3 and 14 days after surgery, respectively, and then declined to near presurgery levels by Day 17. No change in GTH I levels occurred in sham-operated fish. In all groups, GTH II levels were nondetectable and did not change significantly up to 17 days postsurgery In males gonadectomized during spermiation, plasma GTH I levels increased significantly, approximately 10-fold over presurgery levels by 7 days postsurgery, and remained elevated thereafter. in contrast to the males in late spermatogenesis, the spermiating fish had detectable levels of GTH II (2-3 ng/ml), and significant elevations in plasma GTH II levels (approximately 60-fold) were observed 7 days after gonadectomy. These experiments demonstrate that the gonads exert negative feedback effects on secretion of both GTH I and GTH II, but the effect varies seasonally and the nature of the specific factor(s) from the gonads that inhibits and/or stimulates GTH production and secretion remains to be clarified. (C) 1997 Academic Press. C1 UNIV WASHINGTON,SCH FISHERIES,SEATTLE,WA 98195. RP Larsen, DA (reprint author), NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,SEATTLE,WA 98112, USA. NR 67 TC 54 Z9 55 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 0016-6480 J9 GEN COMP ENDOCR JI Gen. Comp. Endocrinol. PD OCT PY 1997 VL 108 IS 1 BP 152 EP 160 DI 10.1006/gcen.1997.6958 PG 9 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA XZ498 UT WOS:A1997XZ49800014 PM 9378269 ER PT J AU German, CR Bourles, DL Brown, ET Hergt, J Colley, S Higgs, NC Ludford, EM Nelsen, TA Feely, RA Raisbeck, G Yiou, F AF German, CR Bourles, DL Brown, ET Hergt, J Colley, S Higgs, NC Ludford, EM Nelsen, TA Feely, RA Raisbeck, G Yiou, F TI Hydrothermal scavenging on the Juan de Fuca Ridge: Th-230(xs), Be-10, and REEs in ridge-flank sediments SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID EAST PACIFIC RISE; MID-ATLANTIC RIDGE; METALLIFEROUS SEDIMENTS; NORTHEAST PACIFIC; MARINE-SEDIMENTS; CLEFT SEGMENT; AMS FACILITY; HOT SPRINGS; OCEAN; PA-231 AB We have investigated the geochemistry of a hydrothermally enriched sediment core recovered from the western flank of the N.Cleft Segment, Juan de Fuca Ridge, similar to 8km west of the ''MegaPlume'' area previously identified near 45 degrees N. The core contains varying biogenic, lithogenic, and hydrothermal components, as reflected in CaCO3, Al, and Fe contents, respectively. Horizons of pronounced hydrothermal input, in core-top sediments and at depth, exhibit increased concentrations of Fe, Cu, Zn, and Pb and shifts in Pb isotopic compositions toward nonradiogenic (MORB/hydrothermal) values. REE concentrations co-vary with hydrothermal Fe down-core, and shale-normalised REE distribution patterns exhibit both negative Ce-anomalies and positive Eu-anomalies, indicative of input from plume-particle fall-out. Unsupported Th-230(xs), activities down-core are consistent with continuous slow sediment accumulation rates of 0.54 cm/ky for similar to 200 ky since the deposition of the deeper Fe-rich horizon. Be-10((0)) and Be-9 isotope concentrations also co-vary with hydrothermal Fe down-core and exhibit Be-10((0))/Be-9 ratios which approach that of Pacific Ocean deep water, indicative of a seawater-scavenging source. Be-10((0))/Th-230(xs(0)) ratios throughout most of Core GC88-6 are greater than mean Pacific Ocean values, indicating that hydrothermal scavenging can lead to significant net removal of dissolved Be-10 into ridge-flank sediments. Copyright (C) 1997 Elsevier Science Ltd. C1 IN2P3,CNRS,CSNSM,ORSAY,FRANCE. UNIV MELBOURNE,SCH EARTH SCI,PARKVILLE,VIC 3052,AUSTRALIA. NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33149. NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. RP German, CR (reprint author), SOUTHAMPTON OCEANOGRAPHY CTR,SOUTHAMPTON SO14 3ZH,HANTS,ENGLAND. NR 49 TC 31 Z9 31 U1 0 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD OCT PY 1997 VL 61 IS 19 BP 4067 EP 4078 DI 10.1016/S0016-7037(97)00230-5 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA YF972 UT WOS:A1997YF97200005 ER PT J AU Elvidge, CD Baugh, KE Hobson, VR Kihn, EA Kroehl, HW Davis, ER Cocero, D AF Elvidge, CD Baugh, KE Hobson, VR Kihn, EA Kroehl, HW Davis, ER Cocero, D TI Satellite inventory of human settlements using nocturnal radiation emissions: A contribution for the global toolchest SO GLOBAL CHANGE BIOLOGY LA English DT Article DE night-time lights; human settlements ID PHOTOPERIOD AB Time series data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) have been used to derive georeferenced inventories of human settlements for Europe, North, and South America, and Asia. The visible band of the OLS is intensified at night, permitting detection of nocturnal visible-near infrared emissions from cities, towns, and villages. The time series analysis makes it possible to eliminate ephemeral VNIR emission sources such as fire and to normalize for differences in the number of cloud-free observations. An examination of the area lit (km(2)) for 52 countries indicates the OLS derived products may be used to perform the spatial apportionment of population and energy related greenhouse gas emissions. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. NOAA,NATL GEOPHYS DATA CTR,SOLAR TERR PHYS DIV,BOULDER,CO 80303. UNIV ALCALA DE HENARES,DEPT GEOG,ALCALA DE HENARES 28801,SPAIN. RP Elvidge, CD (reprint author), UNIV NEVADA,DESERT RES INST,RENO,NV 89506, USA. RI Elvidge, Christopher/C-3012-2009 NR 20 TC 65 Z9 74 U1 2 U2 15 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 1354-1013 J9 GLOB CHANGE BIOL JI Glob. Change Biol. PD OCT PY 1997 VL 3 IS 5 BP 387 EP 395 DI 10.1046/j.1365-2486.1997.00115.x PG 9 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA YA089 UT WOS:A1997YA08900001 ER PT J AU Francis, MH AF Francis, MH TI Aperture-sampling requirements SO IEEE ANTENNAS AND PROPAGATION MAGAZINE LA English DT Article DE m RP Francis, MH (reprint author), NATL INST STAND & TECHNOL,ANTENNA & MAT METROL GRP,BOULDER,CO, USA. NR 1 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1045-9243 J9 IEEE ANTENNAS PROPAG JI IEEE Antennas Propag. Mag. PD OCT PY 1997 VL 39 IS 5 BP 76 EP 77 DI 10.1109/74.637108 PG 2 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA YH412 UT WOS:A1997YH41200010 ER PT J AU Law, DC Khorrami, JR Sessions, WB Shanahan, MK AF Law, DC Khorrami, JR Sessions, WB Shanahan, MK TI Radiation patterns of a large UHF phased-array antenna: A comparison of measurements using satellite repeaters and patterns derived from measurements of antenna current distributions SO IEEE ANTENNAS AND PROPAGATION MAGAZINE LA English DT Article DE phased arrays; antenna measurements; satellite communications; antenna radiation patterns AB The radiation patterns of a 404-MHz phased-array-radar antenna were measured relative to a reference dipole antenna, using 406-MHz repeaters on polar-orbiting satellites and associated ground-station equipment. More than 6000 measurements were collected from the three radar-antenna beams over a five-month period in 1995. The patterns were compared with those derived from measurements of the complex current distributions on the coaxial collinear radiating elements of the antenna. In addition to verifying the antenna specifications for gain, beamwidth, pointing direction, and sidelobe levels, the far-field satellite repeater measurements validated the convenient and inexpensive current measurement and model technique, developed for antenna testing and maintenance. C1 TECHNOSCI INC,LANHAM,MD 20706. COMP SCI CORP,LANHAM,MD 20706. SYST TECHNOL ASSOCIATES,BOULDER,CO 80303. RP Law, DC (reprint author), NOAA,FORECAST SYST LAB REFS3,325 BROADWAY,BOULDER,CO 80303, USA. NR 10 TC 4 Z9 4 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 1045-9243 J9 IEEE ANTENNAS PROPAG JI IEEE Antennas Propag. Mag. PD OCT PY 1997 VL 39 IS 5 BP 88 EP 93 DI 10.1109/74.637109 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA YH412 UT WOS:A1997YH41200014 ER PT J AU Beichl, I Sullivan, F AF Beichl, I Sullivan, F TI Make me a match SO IEEE COMPUTATIONAL SCIENCE & ENGINEERING LA English DT Article C1 IDA CTR COMP SCI,BOWIE,MD. RP Beichl, I (reprint author), NIST,COMP & APPL MATH LAB,GAITHERSBURG,MD 20899, USA. NR 1 TC 0 Z9 0 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 1070-9924 J9 IEEE COMPUT SCI ENG JI IEEE Comput. Sci. Eng. PD OCT-DEC PY 1997 VL 4 IS 4 BP 88 EP 93 DI 10.1109/99.641616 PG 6 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Mathematics, Applied SC Computer Science; Engineering; Mathematics GA YL219 UT WOS:A1997YL21900016 ER PT J AU Sanford, NA AF Sanford, NA TI Introduction to the feature issue on recent advances in lithium niobate optical technology SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Editorial Material RP Sanford, NA (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 0 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 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD OCT PY 1997 VL 33 IS 10 BP 1626 EP 1626 DI 10.1109/JQE.1997.631254 PG 1 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA XX249 UT WOS:A1997XX24900002 ER PT J AU Veasey, DL Gary, JM Amin, J Aust, JA AF Veasey, DL Gary, JM Amin, J Aust, JA TI Time-dependent modeling of erbium-doped waveguide lasers in lithium niobate pumped at 980 and 1480 nm SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE erbium-doped waveguide lasers; integrated optic components; laser modeling; laser radar; lithium niobate ID WAVE-GUIDE LASERS; TI-LINBO3; ER AB We have developed a rigorous phenomenological model for analyzing rare-earth-doped waveguide lasers. The model is based on time-dependent laser rate equations for an arbitrary rare-earth-doped laser host with multiple energy levels. The rate equations are coupled with the laser signal and pump photon flux equations that have time-dependent boundary conditions. The formulation results in a large and stiff set of transcendental and coupled differential equations that are solved using finite difference discretization and the method of lines. Solutions for the laser signal power, pump power, and populations of ion energy levels as functions of space and time are obtained for waveguide lasers. We have used the model to predict the CW characteristics and Q-switched performance of waveguide lasers in lithium niobate pumped by a 980-nm source. Our analysis shows that hole burning can occur in erbium-doped lithium niobate lasers because of the intensity variation across guided transverse modes. We have predicted that Q-switch pulse peak powers can exceed 1 kW with pulsewidths less than 1 ns. Moreover, we have compared the CW and Q-switched performance of 980-nm pumped waveguide lasers and 1480 nm pumped waveguide lasers. An analysis of the effects of host-and fabrication-dependent parameters on CW 980-nm pumped lasers is included. These parameters include cooperative upconversion, excited state absorption, doping concentration, excess waveguide loss, cavity length, and mirror reflectance values. We demonstrate good quantitative agreement with waveguide laser experimental data obtained in our laboratory and with results from the literature. RP Veasey, DL (reprint author), NATL INST STAND & TECHNOL,DIV OPTOELECT,BOULDER,CO 80303, USA. NR 27 TC 43 Z9 43 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 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD OCT PY 1997 VL 33 IS 10 BP 1647 EP 1662 DI 10.1109/3.631259 PG 16 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA XX249 UT WOS:A1997XX24900006 ER PT J AU Bhatt, B Birks, D Hermreck, D AF Bhatt, B Birks, D Hermreck, D TI Digital television: making it work SO IEEE SPECTRUM LA English DT Article C1 MITSUBISHI ELECTR CORP,ADV TELEVIS LAB,MITSUBISHI LABS,SOMERSET,NJ. NIST,ADV TECHNOL PROGRAMS DIGITAL VIDEO INFORMAT NETWO,GAITHERSBURG,MD 20899. RP Bhatt, B (reprint author), SARNOFF CORP,DAVID SARNOFF RES CTR,PRINCETON,NJ 08543, USA. NR 2 TC 14 Z9 14 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 0018-9235 J9 IEEE SPECTRUM JI IEEE Spectr. PD OCT PY 1997 VL 34 IS 10 BP 19 EP 28 DI 10.1109/6.625222 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA YA490 UT WOS:A1997YA49000009 ER PT J AU Damamme, G LeGressus, C DeReggi, AS AF Damamme, G LeGressus, C DeReggi, AS TI Space charge characterization for the 21st century SO IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION LA English DT Review ID SCANNING ELECTRON-MICROSCOPE; INSULATING MATERIALS; THERMAL PULSE; DIELECTRIC-BREAKDOWN; SURFACE; POLARIZATION; FLASHOVER; POLYMERS; VACUUM; RELAXATION AB Various methods of characterizing insulating materials by their ability to take up charge, retain it, and release it, are reviewed critically in search of measurable quantities that could be used to predict material behavior under stress up to failure conditions. Space charge characterization data on different types of materials from polymers to inorganic single crystals and ceramics are surveyed. The charging behavior is found to be influenced by many details such as surface condition and residual stresses, The traditional approach of linking dielectric breakdown to an intrinsic critical field for the material is tested against the newly emerging view that breakdown could be linked to space charge trapping at defect sites and to the attendant energetics of the mechanically strained lattice. The characterization process thus requires more care than was previously thought necessary, but after more research should become more predictive. C1 NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. RP Damamme, G (reprint author), COMMISSARIAT ENERGIE ATOM,BRUYERES CHATEL,FRANCE. NR 146 TC 51 Z9 61 U1 0 U2 13 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1070-9878 J9 IEEE T DIELECT EL IN JI IEEE Trns. Dielectr. Electr. Insul. PD OCT PY 1997 VL 4 IS 5 BP 558 EP 584 DI 10.1109/94.625645 PG 27 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA YD597 UT WOS:A1997YD59700006 ER PT J AU Gordon, RL Sieglaff, DR Rutherford, GH Stricklett, KL AF Gordon, RL Sieglaff, DR Rutherford, GH Stricklett, KL TI Optically enhanced electron attachment by p-benzoquinone SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY AND ION PROCESSES LA English DT Article DE electron attachment; excited states; trochoidal monochromator; mass spectrometry ID NEGATIVE-ION; METHYLATED DERIVATIVES; MOLECULES; CAPTURE; STATES AB The relative rate of formation of long-lived parent anions in p-benzoquinone (BQ) by attachment of electrons with energies between 0 and 3 eV has been measured at an energy resolution of roughly 50 meV using a trochoidal electron monochromatorbased electron impact negative ion mass spectrometer. A comparison of measurements taken near 0 eV shows an increase of the order of 10(5) in the attachment cross-section for BQ molecules excited by UV/visible light from a xenon are lamp over that of ground state molecules. Resonances in attachment by ground state molecules are observed at impact energies of approximately 0.8, 1.0, and 1.3 eV. Negative ion resonances exhibited in the transmitted electron current corroborate these observations. Comparison is made with the results of previous work. (C) 1997 Elsevier Science B.V. C1 GROVE CITY COLL,DEPT PHYS,GROVE CITY,PA 16127. ILLINOIS STATE UNIV,DEPT PHYS,NORMAL,IL 61790. NIST,GAITHERSBURG,MD 20899. RP Gordon, RL (reprint author), US DOE,DIV CHEM SCI ER 142,19901 GERMANTOWN RD,GERMANTOWN,MD 20874, USA. NR 15 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1176 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. Ion Process. PD OCT PY 1997 VL 164 IS 3 BP 177 EP 191 DI 10.1016/S0168-1176(97)00094-3 PG 15 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA YE478 UT WOS:A1997YE47800002 ER PT J AU Lu, J Arya, SP Snyder, WH Lawson, RE AF Lu, J Arya, SP Snyder, WH Lawson, RE TI A laboratory study of the urban heat island in a calm and stably stratified environment .1. Temperature field SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID PLANETARY BOUNDARY-LAYER; MODEL; CONVECTION AB An extensive and systematic water-tank study was performed to simulate the urban heat island under a calm and stably stratified environment. The objective was to examine the mean-temperature field, mixing height, and heat-island intensity as functions of surface heating rates, heat-island sizes, and ambient temperature gradients. The scaling parameters for the temperature field associated with the heat-island plume are the diameter D, surface heating rate H-0, and Brunt-Vaisala frequency N of the ambient stratification. The induced plume was turbulent, and the Froude number was found to be the most important similarity parameter. The differences between low- and high-aspect-ratio plumes are discussed, and simple theoretical models are proposed for low-aspect-ratio plumes. The experimental results generally confirm the theoretical predictions and agree reasonably well with field observations, in spite of several limitations of the laboratory simulation. The mean-temperature distributions are found to have a universal shape that is a function of location only. The results are described in two papers. In this paper, the temperature fields are described. Part II describes the velocity fields and develops analytical models that apply to low-aspect-ratio plumes. C1 N CAROLINA STATE UNIV,DEPT MARINE EARTH & ATMOSPHER SCI,RALEIGH,NC 27695. NOAA,ATMOSPHER SCI MODELING DIV,AIR RESOURCES LAB,RES TRIANGLE PK,NC. NR 42 TC 50 Z9 53 U1 0 U2 5 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 OCT PY 1997 VL 36 IS 10 BP 1377 EP 1391 DI 10.1175/1520-0450(1997)036<1377:ALSOTU>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XY744 UT WOS:A1997XY74400006 ER PT J AU Lu, J Arya, SP Snyder, WH Lawson, RE AF Lu, J Arya, SP Snyder, WH Lawson, RE TI A laboratory study of the urban heat island in a calm and stably stratified environment .2. Velocity field SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID PLANETARY BOUNDARY-LAYER; MODEL AB A fully turbulent, low-aspect-ratio buoyant plume with no initial momentum under calm and stably stratified conditions is produced in a convection tank. The plume is generated by a circular heat island at the bottom of the tank. Two analytical models, a bulk convection model and a hydrostatic model, are developed to formulate similarity relations for the low-aspect-ratio plume. The convective velocity scale W-D, suggested by the analytical models, is used as the similarity parameter for both the mean velocity and standard deviations of velocity fluctuations. The normalized standard deviations of horizontal and vertical velocities agree with each other for two heating rates, as well as with field observations in the center of Sapporo, Japan. The suggested scaling and empirical relations based on our experimental results may be applied to the velocity fields of other low-aspect-ratio plumes in calm and stably stratified environments. Further investigations are recommended to confirm the results of the current study. C1 N CAROLINA STATE UNIV,DEPT MARINE EARTH & ATMOSPHER SCI,RALEIGH,NC 27695. NOAA,ATMOSPHER SCI MODELING DIV,AIR RESOURCES LAB,RES TRIANGLE PK,NC. NR 14 TC 35 Z9 37 U1 0 U2 4 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 OCT PY 1997 VL 36 IS 10 BP 1392 EP 1402 DI 10.1175/1520-0450(1997)036<1392:ALSOTU>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XY744 UT WOS:A1997XY74400007 ER PT J AU Joyce, R Arkin, PA AF Joyce, R Arkin, PA TI Improved estimates of tropical and subtropical precipitation using the GOES precipitation index SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CLOUD-CLIMATOLOGY-PROJECT; RAINFALL; COVER AB Nine years (1986-94) of tropical and subtropical precipitation estimates based on the GOES precipitation index (GPI) are examined. The GPI, based on the results of studies relating fractional coverage of cold cloud to convective rainfall, uses IR observations gathered by geostationary and polar-ol biting satellites. Longitudinal discontinuities in mean GPI coincident with the boundaries of satellite coverage led to a comparison of GPI derived from each geostationary satellite in overlap regions. This study revealed both intersatellite calibration differences and satellite zenith angle dependence. Its goals are to remove these sources of systematic error within the GPI, investigate the climatology of the corrected GPI, and compare against other estimated rainfall datasets. To correct calibration differences. Global Precipitation Climatology Project geostationary satellite IR data are standardized to one satellite by temperature adjustments deduced by the International Satellite Cloud Climatology Project. The resulting GPI values are corrected for zenith angle dependence based on a comparison between GOES-7 and Metosat-3 that found a systematic increase in GPI of 9% for every 10 degrees of zenith angle beyond 25 degrees. The corrections remove noticeable discontinuities in time-averaged GPI and are largest (>2 mm day(-1)) over the eastern Indian Ocean, the equatorial Pacific near the date line, and South America. The spatial correlation between corrected GPI and rainfall derived from rain gauges is greater than 0.8 in tropical regions with adequate gauge density. Empirical orthogonal functions of monthly anomalies of corrected GPI show the expected El Nino-Southern Oscillation spatial pattern. RP Joyce, R (reprint author), NOAA,NATL WEATHER SERV,NATL CTR ENVIRONM PREDICT,CLIMATE PREDICT CTR,8605A,WASHINGTON,DC 20233, USA. RI Arkin, Phillip/F-5808-2010 NR 20 TC 45 Z9 47 U1 0 U2 2 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 OCT PY 1997 VL 14 IS 5 BP 997 EP 1011 DI 10.1175/1520-0426(1997)014<0997:IEOTAS>2.0.CO;2 PG 15 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XX162 UT WOS:A1997XX16200001 ER PT J AU Mayor, SD Lenschow, DH Schwiesow, RL Mann, J Frush, CL Simon, MK AF Mayor, SD Lenschow, DH Schwiesow, RL Mann, J Frush, CL Simon, MK TI Validation of NCAR 10.6-mu m CO2 Doppler lidar radial velocity measurements and comparison with a 915-MHz profiler SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID COHERENT LASER-RADAR; BOUNDARY-LAYER; SOUNDING SYSTEM; WIND PROFILER; PERFORMANCE; FLUXES; 2-MU-M; HEAT AB The capability of the NCAR 10.6-mu m-wavelength CO2 Doppler lidar to measure radial air motion is validated by examining hard-target test data, comparing measurements with those from a two-axis propeller anemometer and a 915-MHz profiling radar, and analyzing power spectra and autocovariance functions of the lidar radial velocities in a daytime convective boundary layer. Results demonstrate that the lidar is capable of measuring radial velocity to less than 0.5 m s(-1) precision from 20 laser pulse averages under high signal-to-noise ratio conditions. Hard-target test data and comparisons with other sensors show that the lidar data can be biased by as much as +/-2 m s(-1) when operating in the coherent oscillator mode and that correlated errors are negligible. Correlation coefficients are as large as 0.96 for 90-min comparisons of horizontal velocities averaged for 1 min from the lidar and anemometer, and 0.87 for 2.5-h comparisons between vertical velocities averaged for 30 s from the lidar and profiler. Comparisons of the lidar and profiler vertical velocities are particularly encouraging for the profiler since these results show that 915-MHz profilers are capable of making good vertical velocity measurements in strong convective boundary layers. The authors conclude that despite the commonplace systematic bias in lidar radial velocity, ground-based operation of the NCAR CO2 Doppler lidar can provide valuable velocity data for meso- and microscale meteorological studies. The lidar can also provide filtered velocity statistics that may be useful for boundary layer turbulence research. C1 NATL CTR ATMOSPHER RES,BOULDER,CO 80307. BALL AEROSP & TECHNOL CORP,BOULDER,CO. RISO NATL LAB,DK-4000 ROSKILDE,DENMARK. NOAA,BOULDER,CO. OI LENSCHOW, DONALD/0000-0003-4353-0098 NR 68 TC 24 Z9 24 U1 0 U2 2 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 OCT PY 1997 VL 14 IS 5 BP 1110 EP 1126 DI 10.1175/1520-0426(1997)014<1110:VONMCD>2.0.CO;2 PG 17 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XX162 UT WOS:A1997XX16200009 ER PT J AU Cogan, J Measure, E Wolfe, D AF Cogan, J Measure, E Wolfe, D TI Atmospheric soundings in near-real time from combined satellite and ground-based remotely sensed data SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID PROFILER; TEMPERATURE; ACCURACY; SYSTEM AB A mobile profiling system has been developed that is capable of probing the atmosphere from the surface to over 30 km. The Mobile Profiling System (MPS) combines ground-based instruments, including a five-beam 924-MHz radar wind profiler, a radio acoustic sounding system, and two passive microwave sounders, with a receiver and processor for meteorological satellite data. Software in the MPS produces profiles from the surface to the highest satellite sounding level by combining surface data and profiles generated from the suite of groundbased sensors with those from a meteorological satellite. The algorithms generate soundings of temperature, humidity, wind velocity, and other meteorological variables. The method for combining data from the separate sources is not site specific and requires no a priori information. The MPS has the potential for a variety of applications, including detailed analysis of meteorological variables for research and operations over mesoscale areas, such as regional pollution studies and severe storm forecasting. This paper describes the method for merging data From satellite and ground-based remote sensing systems, and presents results from a series of field tests of both individual sensors and combined soundings. Accuracy of the combined soundings appears comparable to that from rawinsonde with the exception of wind velocity at satellite sounding altitudes. The MPS has operated successfully in several different climates: in the Los Angeles Free Radical Experiment at Claremont, California, and in tests at White Sands Missile Range, New Mexico; Erie, Colorado; Ft. Sill, Oklahoma; and Wallops Island, Virginia. C1 NOAA,ENVIRONM TECHNOL LAB,BOULDER,CO. RP Cogan, J (reprint author), USA,RES LAB,AMSRL,IS,EA,BLDG 1622,WHITE SANDS MISSILE RANGE,NM 88002, USA. NR 28 TC 11 Z9 11 U1 1 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 OCT PY 1997 VL 14 IS 5 BP 1127 EP 1138 DI 10.1175/1520-0426(1997)014<1127:ASINRT>2.0.CO;2 PG 12 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XX162 UT WOS:A1997XX16200010 ER PT J AU Zhao, CL Bakwin, PS Tans, PP AF Zhao, CL Bakwin, PS Tans, PP TI A design for unattended monitoring of carbon dioxide on a very tall tower SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID TROPOSPHERE; CO2 AB Unattended measurements of carbon dioxide (CO2) mixing ratio at three altitudes up to 496 m above the surface on a television transmitter tower in the southeastern United States have been made for a period of 4 yr. This report describes the design of the automatic tower measuring system in detail. A nondispersive infrared (NDIR) analyzer is used to measure the CO2 concentration continuously. Real-time control and data collection uses a PC 486 running under the multitasking operating system QNX. The CO2 data show strong diurnal and seasonal variations, and large vertical gradients. A comparison of this study's continental tower data with data from ''background'' sites should provide a strong constraint for regional and global models of terrestrial CO2 fluxes. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Zhao, CL (reprint author), NOAA,CLIMATE MONITORING & DIAGNOST LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 12 TC 26 Z9 26 U1 0 U2 2 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 OCT PY 1997 VL 14 IS 5 BP 1139 EP 1145 DI 10.1175/1520-0426(1997)014<1139:ADFUMO>2.0.CO;2 PG 7 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XX162 UT WOS:A1997XX16200011 ER PT J AU Plimpton, PE Freitag, HP McPhaden, MJ AF Plimpton, PE Freitag, HP McPhaden, MJ TI ADCP velocity errors from pelagic fish schooling around equatorial moorings SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID OCEAN AB Beginning in 1990, PROTEUS (profile telemetry of upper ocean currents) moorings have been deployed in the equatorial Pacific with the ability to transmit ocean current measurements to shore in real time via satellite. The surface moorings were equipped with 153.6-kHz RD Instruments acoustic Doppler current profilers (ADCPs), along with mechanical current meters (MCMs) at six or seven depths. At times, large bias errors were found in the ADCP velocities relative to MCM velocities, due to the reflection of acoustic energy from fish in the vicinity of the moorings. An algorithm was subsequently developed and added to the ADCP firmware in an attempt to identify and reject fish-affected data before ensemble averaging of individual pings. The algorithm rejected some fish-biased data, but large velocity errors still occurred in the ADCP averages. A technique utilizing empirical orthogonal functions of ADCP-MCM speed differences was developed to correct the ADCP velocities after mooring recovery. The corrected daily averaged time series were found accurate to within +/-5 cm s(-1) at the depths where significant fish bias occurred. RP Plimpton, PE (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,7600 SAND POINT WAY NE,BLDG 3,SEATTLE,WA 98115, USA. RI McPhaden, Michael/D-9799-2016 NR 15 TC 17 Z9 17 U1 0 U2 2 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 OCT PY 1997 VL 14 IS 5 BP 1212 EP 1223 DI 10.1175/1520-0426(1997)014<1212:AVEFPF>2.0.CO;2 PG 12 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XX162 UT WOS:A1997XX16200017 ER PT J AU Emery, WJ Cherkauer, K Shannon, B Reynolds, RW AF Emery, WJ Cherkauer, K Shannon, B Reynolds, RW TI Hull-mounted sea surface temperatures from ships of opportunity SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB The design and deployment of an inexpensive hull temperature sensor and data logger system was undertaken for the purpose of improving the measurement of sea surface temperature (SST) by ship-of-opportunity merchant vessels. The resulting hull sensors and data logger systems were installed on four merchant vessels and one research vessel. A variety of installations tested the effects of placement and insulation on the temperature sensors themselves. The resulting hull SST data were compared with monthly SST analyses using optimal interpolation (OI) as well as with data from the thermosalinograph (TSG) on board the research vessel. The data collected from the hull sensor systems, while being slightly offset from the TSG data (likely due to a TSG calibration problem), were found to be in excellent agreement with the monthly OI data. C1 NATL CTR ENVIRONM PREDICT, COUPLED MODEL PROJECT, WASHINGTON, DC USA. RP Emery, WJ (reprint author), UNIV COLORADO, COLORADO CTR ASTRODYNAM RES, BOX 431, BOULDER, CO 80309 USA. RI Cherkauer, Keith/D-6510-2014; OI Cherkauer, Keith/0000-0002-6938-5303; Emery, William/0000-0002-7598-9082 NR 4 TC 7 Z9 7 U1 1 U2 3 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 OCT PY 1997 VL 14 IS 5 BP 1237 EP 1251 DI 10.1175/1520-0426(1997)014<1237:HMSSTF>2.0.CO;2 PG 15 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XX162 UT WOS:A1997XX16200020 ER PT J AU Higgins, RW Yao, Y Wang, XL AF Higgins, RW Yao, Y Wang, XL TI Influence of the North American monsoon system on the US summer precipitation regime SO JOURNAL OF CLIMATE LA English DT Article ID CENTRAL UNITED-STATES; MARITIME TROPICAL AIR; LOW-LEVEL JET; DIURNAL-VARIATIONS; MEXICAN MONSOON; MOISTURE BUDGET; CLIMATOLOGY; GULF; CALIFORNIA; SOUTHWEST AB Key features of the U.S. summer precipitation regime are examined within the context of the evolving North American monsoon system. The focus is on the antecedent and subsequent atmospheric conditions over the conterminous United Stares relative to the onset of monsoon precipitation over the southwestern United States, which typically begins in early July. The onset of the monsoon in this region is determined using a precipitation index, based on daily observed precipitation for a 31-yr (1963-94) period. Lagged composites of the observed precipitation and various fields from the NCEP-NCAR reanalysis for the period 1979-94 provide a comprehensive picture of atmospheric conditions during the evolution of the U.S. warm season precipitation regime. The summer precipitation regime is characterized by an out-of-phase relationship between precipitation over the Southwest and the Great Plains-northern tier and an in-phase relationship between precipitation over the Southwest and the East Coast. Changes in the upper-tropospheric wind and divergence fields (mean vertical motion) are broadly consistent with the evolution of this precipitation pattern. Enhanced upper-tropospheric divergence in the vicinity and south of the upper-tropospheric monsoon high coincides with enhanced upper-tropospheric easterlies and Mexican monsoon rainfall after onset. Over the Great Plains and along the northern tier, the middle-and upper-tropospheric flow is more convergent and rainfall diminishes after onset to the north and east of the monsoon high. The frequency of occurrence of the Great Plains low-level jet (LLJ) and southerly moisture transport change little during the evolution. However, LLJ-related precipitation is controlled by changes in the large-scale flow related to the North American monsoon system. There is increased upper-tropospheric divergence and precipitation after onset in the vicinity of an ''induced'' trough over the eastern United States. The pattern of evaporation minus precipitation from the NCEP-NCAR reanalysis shows broad consistency with the divergence of the vertically integrated flux of water vapor during the monsoon, although the resolution in the NCEP-NCAR reanalysis is inadequate to yield quantitatively accurate regional estimates of these fields. In agreement with earlier studies, the NCEP-NCAR reanalysis indicates that most of the moisture below 850 hPa over the desert Southwest comes from the northern Gulf of California, while most of the moisture at and above 850 hPa arrives from over the Gulf of Mexico. C1 RES & DATA SYST CORP,GREENBELT,MD. RP Higgins, RW (reprint author), NOAA,NATL WEATHER SERV,NCEP,CLIMATE PREDICT CTR,WASHINGTON,DC 20233, USA. RI Wang, Julian/C-3188-2016 NR 44 TC 273 Z9 275 U1 1 U2 39 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD OCT PY 1997 VL 10 IS 10 BP 2600 EP 2622 DI 10.1175/1520-0442(1997)010<2600:IOTNAM>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YC705 UT WOS:A1997YC70500013 ER PT J AU Misra, DN AF Misra, DN TI Interaction of ortho-phospho-L-serine with hydroxyapatite: Formation of a surface complex SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE adsorption; dissolution; hydroxyapatite; o-phospho-L-serine; uptake; surface complex ID INTERFACIAL PROPERTIES; AQUEOUS-SOLUTION; CALCIUM; ADSORPTION; PRECIPITATION; EXCHANGE; IONS AB ortho-Phospho-L-serine (H-2 Psi, where Psi represents the serine-phosphato ion), a constituent of salivary proteins, seems to play an important role in the mineralization of teeth, To understand the basic mechanism of this interaction, the uptake of o-phospho-L-serine from relatively concentrated aqueous solutions (up to 100 mmol/L) onto synthetic hydroxyapatite was studied. Previous studies have shown that in the dilute concentration range(<12.5 mmol/L) the uptake followed a regular Langmuirian adsorption plot. At higher concentrations the uptake curve increased steeply, but no formation of a separate phase in the reacted apatite was discernible, either by optical or by scanning electron microscopy, The dissolution of apatite released phosphate and calcium ions into the solution in amounts linearly related to the uptake of serine with P/Psi = 1 and Ca/Psi = 2, The charge and mass balance of the reaction can be reconciled with the formation of the surface complex (shown within brackets): Ca-10(OH)(2)(PO4)(6) + 6H(2) Psi --> [Ca-6(H Psi)(2)(HPO4)(2)(PO4)(2)] + 4Ca(2+) + 2H Psi(1-) + 2 Psi(2-) + 2H(2)PO(4)(1-) + 2H(2)O. The formation of two other surface complexes is possible; however, the complex shown above probably disrupts the apatite lattice the least, Traces of Ca Psi.H2O precipitate out from the filtrates of highly concentrated solutions after 6 days. (C) 1997 Academic Press. RP Misra, DN (reprint author), NIST,AMER DENT ASSOC HLTH FDN,PAFFENBARGER RES CTR,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 28 TC 15 Z9 15 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 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD OCT 1 PY 1997 VL 194 IS 1 BP 249 EP 255 DI 10.1006/jcis.1997.5108 PG 7 WC Chemistry, Physical SC Chemistry GA YG926 UT WOS:A1997YG92600026 ER PT J AU Chin, JW Nguyen, T Aouadi, K AF Chin, JW Nguyen, T Aouadi, K TI Effects of environmental exposure on fiber-reinforced plastic (FRP) materials used in construction SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article; Proceedings Paper CT 1st Symposium on Non-Aerospace Applications for Composite Materials CY NOV, 1996 CL NEW ORLEANS, LA SP Amer Soc Testing & Mat, Comm D 30 Composite Mat DE alkaline conditions; building technology; composites; durability; polyester; moisture; saline conditions; vinyl ester; ultraviolet radiation AB A major hindrance to the acceptance of polymer composites in civil engineering applications is the susceptibility of the polymeric matrix to weathering. The polymer matrix is prone to degradation initiated by ultraviolet (UV) radiation, moisture, temperature, and high pH environments. The objective of this study was to characterize chemical and physical changes in polymeric matrix resins following exposure to these environments. The ultimate goal is to identify factors that contribute to matrix resin degradation under environmental and mechanical stresses. Resin systems studied included vinyl ester and isophthalic polyester, both of which are commonly used in construction applications. Neat polymer films were exposed to UV radiation, moisture, alkaline, and saline environments. Diffusion of water, alkali, and saline solution into the polymers was calculated from gravimetric measurements. Changes in strength, viscoelastic response, and thermal properties were evaluated through tensile testing, dynamic mechanical thermal analysis (DMTA), and differential scanning calorimetry (DSC). Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were also used for detecting changes in the polymer surface following UV exposure. RP Chin, JW (reprint author), NATL INST STAND & TECHNOL,BLDG 226,ROOM B350,GAITHERSBURG,MD 20899, USA. NR 22 TC 73 Z9 75 U1 3 U2 29 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD OCT PY 1997 VL 19 IS 4 BP 205 EP 213 PG 9 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA YG908 UT WOS:A1997YG90800003 ER PT J AU Xu, HHK Kelly, JR Jahanmir, S Thompson, VP Rekow, ED AF Xu, HHK Kelly, JR Jahanmir, S Thompson, VP Rekow, ED TI Enamel subsurface damage due to tooth preparation with diamonds SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE enamel; fracture; subsurface; tooth preparation ID FRACTURE PROPERTIES; GRAIN-SIZE; CERAMICS; DENTIN AB In clinical tooth preparation with diamond burs, sharp diamond particles indent and scratch the enamel, causing material removal. Such operations may produce subsurface damage in enamel. However, little information is available on the mechanisms and the extent of subsurface damage in enamel produced during clinical tooth preparation. The aim of this study, therefore, was to investigate the mechanisms of subsurface damage produced in enamel during tooth preparation by means of diamond burs, and to examine the dependence of such damage on enamel rod orientation, diamond particle size, and removal rate. Subsurface damage was evaluated by a bonded-interface technique. Tooth preparation was carried out on two enamel rod orientations, with four clinical diamond burs (coarse, medium, fine, and superfine) used in a dental handpiece. The results of this study showed that subsurface damage in enamel took the form of median-type cracks and distributed microcracks, extending preferentially along the boundaries between the enamel rods. Microcracks within individual enamel rods were also observed. The median-type cracks were significantly longer in the direction parallel to the enamel rods than perpendicular to the rods. Preparation with the coarse diamond bur produced cracks as deep as 84 +/- 30 mu m in enamel. Finishing with fine diamond burs was effective in crack removal. The crack lengths in enamel were not significantly different when the removal rate was varied. Based on these results, it is concluded that subsurface damage in enamel induced by tooth preparation takes the form of median-type cracks as well as inter-and intra-rod microcracks, and that the lengths of these cracks are sensitive to diamond particle size and enamel rod orientation, but insensitive to removal rate. C1 NIST, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. Naval Dent Sch, Bethesda, MD 20889 USA. Univ Maryland, Dept Operat Dent, Baltimore, MD 21201 USA. Univ Med & Dent New Jersey, Dept Orthodont, Newark, NJ 07103 USA. RP Xu, HHK (reprint author), NIST, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Bldg 224,Room A-153, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [1 P01DE10976-01A1] NR 16 TC 60 Z9 63 U1 1 U2 4 PU INT AMER ASSOC DENTAL RESEARCHI A D R/A A D R PI ALEXANDRIA PA 1619 DUKE ST, ALEXANDRIA, VA 22314-3406 USA SN 0022-0345 J9 J DENT RES JI J. Dent. Res. PD OCT PY 1997 VL 76 IS 10 BP 1698 EP 1706 PG 9 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA YU391 UT WOS:000071712400012 PM 9326903 ER PT J AU Vandas, M Fischer, S Dryer, M Smith, Z Detman, T Geranios, A AF Vandas, M Fischer, S Dryer, M Smith, Z Detman, T Geranios, A TI MHD simulation of an interaction of a shock wave with a magnetic cloud SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY; PROPAGATION; AU AB Interplanetary shock waves, propagating in the heliosphere faster than earlier-emitted coronal ejecta, penetrate them and modify their parameters during this interaction. Using two and one half dimensional MHD simulations, we show how a magnetic cloud ( flux rope) propagating with a speed 3 times higher than the ambient solar wind is affected by an even faster traveling shock wave overtaking the cloud. The magnetic field increases inside the cloud during the interaction as it is compressed in the radial direction and becomes very oblate. The cloud is also accelerated and moves faster, as a whole, while both shocks (driven by the cloud and the faster interplanetary shock) merge upstream of the cloud. This interaction may be a rather common phenomenon due to the frequency of coronal mass ejections and occurrence of shock waves during periods of high solar activity. C1 NOAA,SPACE ENVIRONM CTR,RESE,BOULDER,CO 80303. UNIV ATHENS,NUCL & PARTICLE PHYS SECT,DEPT PHYS,ATHENS 15771,GREECE. RP Vandas, M (reprint author), ACAD SCI CZECH REPUBL,INST ASTRON,BOCNI II 1401,PRAGUE 14131 4,CZECH REPUBLIC. RI Vandas, Marek/G-9054-2014; xue, yansheng/A-9712-2012 NR 13 TC 38 Z9 40 U1 1 U2 1 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 OCT 1 PY 1997 VL 102 IS A10 BP 22295 EP 22300 DI 10.1029/97JA01675 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XZ208 UT WOS:A1997XZ20800024 ER PT J AU Croley, TE AF Croley, Thomas E., II TI MIXING PROBABILISTIC METEOROLOGY OUTLOOKS IN OPERATIONAL HYDROLOGY SO JOURNAL OF HYDROLOGIC ENGINEERING LA English DT Article AB There are now several kinds of probabilistic meteorology outlooks available to the water resource engineer or hydrologist. These outlooks are defined over different time periods at different lag times, and they forecast either event probabilities or only most-probable events. An existing operational hydrology approach (for making hydrology outlooks) builds a set of hydrological possibilities from past meteorology to match forecast event probabilities, but it does not consider most-probable event forecasts. This approach is extended to mix both types of probabilistic meteorology outlooks in determining weights to apply to the set of hydrological possibilities to make hydrological outlooks. Boundary condition equations for the weights are constructed corresponding to forecast event probabilities; and boundary condition inequalities are constructed corresponding to forecast most-probable events. The inequalities are converted to equivalent equations through the introduction of additional variables. The resulting set of all boundary condition equations is solved for physically relevant values. The solution is an optimization problem for the general case, similar to earlier consideration of only forecast event probabilities. An example illustrates the concepts and methods. C1 NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. RP Croley, TE (reprint author), NOAA, Great Lakes Environm Res Lab, 2205 Commonwealth Blvd, Ann Arbor, MI 48105 USA. NR 5 TC 10 Z9 10 U1 0 U2 2 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 1084-0699 J9 J HYDROL ENG JI J. Hydrol. Eng. PD OCT PY 1997 VL 2 IS 4 BP 161 EP 168 DI 10.1061/(ASCE)1084-0699(1997)2:4(161) PG 8 WC Engineering, Civil; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA V15AJ UT WOS:000207774600003 ER PT J AU Edgar, JH Wei, CH Smith, DT Kistenmacher, TJ Bryden, WA AF Edgar, JH Wei, CH Smith, DT Kistenmacher, TJ Bryden, WA TI Hardness, elastic modulus and structure of indium nitride thin films on AlN-nucleated sapphire substrates SO JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS LA English DT Article AB The structural properties of epitaxial indium nitride thin films were characterized and related to the mechanical properties as measured by nanoindentation. The seven epitaxial InN films examined were deposited over the temperature range 200-400 degrees C by reactive magnetron sputtering on (00.1) sapphire substrates buffered with a thin AlN layer. The hardness, surface texture and crystal quality of the InN films were functions of the deposition temperature, with the maximum hardness (11.2 GPa), the smoothest surface, the minimum c-lattice constant (0.5708 nm), and the minimum (00.4) X-ray rocking curve width (0.6 degrees) all occurring at the deposition temperature of 350 degrees C. The crystal quality and the hardness of the InN films degraded at both higher and lower temperatures. C1 NIST, DIV CERAM, GAITHERSBURG, MD 20899 USA. JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MD 20723 USA. 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 12 TC 18 Z9 18 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0957-4522 J9 J MATER SCI-MATER EL JI J. Mater. Sci.-Mater. Electron. PD OCT PY 1997 VL 8 IS 5 BP 307 EP 312 DI 10.1023/A:1018587306451 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA YA171 UT WOS:A1997YA17100005 ER PT J AU Westbrook, CI Jurczak, C Birkl, G Desruelle, B Phillips, WD Aspect, A AF Westbrook, CI Jurczak, C Birkl, G Desruelle, B Phillips, WD Aspect, A TI A study of atom localization in an optical lattice by analysis of the scattered light SO JOURNAL OF MODERN OPTICS LA English DT Article ID LASER-COOLED ATOMS; INTENSITY CORRELATIONS; CESIUM ATOMS; FLUORESCENCE; MOLASSES; WAVE AB We present an experimental study of a four-beam optical lattice using the light scattered by the atoms in the lattice. We use both intensity correlations and observations of the transient behaviour of the scattering when the lattice is suddenly switched on. We compare results for three different configurations of the optical lattice. We create situations in which the Lamb-Dicke effect is negligible and show that, in contrast with what has been stated in some of the literature, the damping rate of the 'coherent' atomic oscillations can be much longer than the inelastic photon scattering rate. C1 UNIV HANNOVER,INST QUANTENOPT,D-30167 HANNOVER,GERMANY. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Westbrook, CI (reprint author), INST OPT,CNRS,UA 14,BP 147,F-91403 ORSAY,FRANCE. RI Westbrook, Christoph/B-6092-2009 OI Westbrook, Christoph/0000-0002-6490-0468 NR 40 TC 8 Z9 8 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD OCT PY 1997 VL 44 IS 10 BP 1837 EP 1851 DI 10.1080/09500349708231850 PG 15 WC Optics SC Optics GA YC600 UT WOS:A1997YC60000010 ER PT J AU Benson, O Weidinger, M Raithel, G Walther, H AF Benson, O Weidinger, M Raithel, G Walther, H TI Atomic interference in the micromaser and statistical properties of the micromaser field SO JOURNAL OF MODERN OPTICS LA English DT Article ID MASER AB In this paper we report on atomic interferometry in the micromaser. The atomic inversion is recorded while scanning the cavity frequency across the atomic resonance. For high pump rates, interference patterns are observed on the low-frequency wing of the maser line. The interferences are due to the non-adiabatic mixing of dressed states of the atoms at the entrance and exit holes of the maser cavity, leading to a Ramsey-type two-field interaction. Furthermore, statistical properties of the maser field are investigated via a measurement of the statistics of the pump atoms that leave the maser cavity. Theoretical expressions for the time dependence of the Fano-Mandel parameter Q(A)(t) are compared with the experimental data. We demonstrate, that metastability of the maser field and atomic interference strongly influence the approach to a steady-state value of Q(A)(t). C1 MAX PLANCK INST QUANTUM OPT,D-85748 GARCHING,GERMANY. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Benson, O (reprint author), UNIV MUNICH,SEKT PHYS,D-85748 GARCHING,GERMANY. RI Benson, Oliver/C-1953-2012 NR 14 TC 3 Z9 3 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD OCT PY 1997 VL 44 IS 10 BP 2011 EP 2019 DI 10.1080/09500349708231862 PG 9 WC Optics SC Optics GA YC600 UT WOS:A1997YC60000022 ER PT J AU Tezcan, FA Varberg, TD Stroh, F Evenson, KM AF Tezcan, FA Varberg, TD Stroh, F Evenson, KM TI Far-infrared rotational spectra of ZnH and ZnD in the X-2 Sigma(+) (v=0) state SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID GROUND-STATE; RADICALS; SPECTROSCOPY; MOLECULES; CDH AB Several rotational transitions of zinc hydride and deuteride within the upsilon = 0 level of the X-2 Sigma(+) state have been measured in both electron spin components over the ranges N '' = 2 to 10 for ZnH and N '' = 9 to 21 for ZnD, A least-squares fit to these data in combination with low-N microwave data measured by Ether workers has resulted in improved values of the rotational, fine, and hyperfine structure constants. The values of the proton hyperfine constants are discussed in the context of a molecular orbital analysis of zinc hydride. (C) 1997 Academic Press. C1 MACALESTER COLL, DEPT CHEM, ST PAUL, MN 55105 USA. NATL INST STAND & TECHNOL, DIV TIME & FREQUENCY, BOULDER, CO 80303 USA. RI Stroh, Fred/A-6505-2009 OI Stroh, Fred/0000-0002-4492-2977 NR 17 TC 7 Z9 7 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 EI 1096-083X J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD OCT PY 1997 VL 185 IS 2 BP 290 EP 295 DI 10.1006/jmsp.1997.7424 PG 6 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA YG961 UT WOS:A1997YG96100010 ER PT J AU Graczyk, TK Fayer, R Lewis, EJ Farley, CA Trout, JM AF Graczyk, TK Fayer, R Lewis, EJ Farley, CA Trout, JM TI In vitro interactions between hemocytes of the Eastern oyster, Crassostrea virginica Gmelin, 1791 and Cryptosporidium parvum oocysts SO JOURNAL OF PARASITOLOGY LA English DT Article ID MARINE WATERS AB It was demonstrated by an in vitro slide phagocytosis assay that hemocytes of the Eastern oyster, Crassostrea virginica Gmelin, 1791 are capable of rapid recognition and internalization of infectious Cryptosporidium parvum (AUCP-1 strain) oocysts. The incubation of hemocyte monolayers (8.5 X 10(4) cells) that had received 6.8 X 10(5) or 3.4 x 10(5) oocysts was arrested at 5, 15, 30, 60, 90, and 120 min and the oocysts detected by acid-fast stain and immunofluorescent antibody (IFAT). An average of 20.5, 38.3, 50.2, 58.9, 69.0, and 75.0% oocysts were phagocytosed after 5, 15, 30, 60, 90, and 120 min, respectively. The intensity of fluorescence of phagocytosed oocysts significantly decreased over time (P < 0.01), and their round shape was altered. The number of cells containing oocysts and the mean number of ingested oocysts (range: 1.2-4.5 per cell) increased significantly over time (P < 0.01), whereas the numbers of nonphagocytosed oocysts that were adherent to the glass slides significantly decreased (P < 0.05). By extrapolation, the results indicate that Cr. virginica is capable of internalizing up to 6.4 x 10(6) Cryptosporidium oocysts per mi of its hemolymph. C1 ARS,IMMUN & DIS RESISTANCE LAB,INST LIVESTOCK & POULTRY SCI,USDA,BELTSVILLE,MD 20705. NATL MARINE FISHERIES SERV,NATL OCEAN & ATMOSPHER ADM,US DEPT COMMERCE,OXFORD,MD 21654. RP Graczyk, TK (reprint author), JOHNS HOPKINS UNIV,SCH HYG & PUBL HLTH,DEPT MOL MICROBIOL & IMMUNOL,615 N WOLFE ST,BALTIMORE,MD 21205, USA. NR 20 TC 16 Z9 16 U1 1 U2 1 PU AMER SOC PARASITOLOGISTS PI LAWRENCE PA 810 EAST 10TH STREET, LAWRENCE, KS 66044 SN 0022-3395 J9 J PARASITOL JI J. Parasitol. PD OCT PY 1997 VL 83 IS 5 BP 949 EP 952 DI 10.2307/3284296 PG 4 WC Parasitology SC Parasitology GA YB398 UT WOS:A1997YB39800031 PM 9379306 ER PT J AU Johns, E Fine, RA Molinari, RL AF Johns, E Fine, RA Molinari, RL TI Deep flow along the western boundary south of the Blake Bahama Outer Ridge SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID NORTH-ATLANTIC OCEAN; DENMARK STRAIT OVERFLOW; THERMOHALINE CIRCULATION; CURRENT VARIABILITY; WATER MASSES; ABACO-ISLAND; GULF-STREAM; 26.5-DEGREES-N; EAST; TRANSPORT AB In June-July 1990, hydrographic, chlorofluorocarbon (CFC), and velocity observations were taken along the western boundary of the North Atlantic south of the Blake Bahama Outer Ridge from 30 degrees to 24 degrees N between the northern Bahamas and 71 degrees W. The deep flow in the region, associated with the deep western boundary current, forms a pattern of strong, narrow currents and cyclonic gyres close to the continental slope with broad, slower southward flow offshore. The CFCs reveal that the most recently ''ventilated'' water (i.e., having the highest CFC concentrations due to more recent contact with the atmosphere in the northern North Atlantic) is found along the western boundary in two distinct cores between potential temperatures 4 degrees-6 degrees C and 1.9 degrees-2.4 degrees C. Geostrophic transport streamlines were constructed for the deep flow, referenced using direct velocity observations at 26.5 degrees N and assuming mass conservation between closed areas bounded by the hydrographic sections. The tracers and transports are used together to describe the deep circulation in the region, to determine the origins and pathways of the various flow components, to define the spatial scales and strengths of the deep currents and recirculation gyres, and to examine their relationship to bottom topography and their possible role in ventilating the interior. The close correspondence of the tracer distributions with the regional bottom topography implies that the major topographic features in this region strongly influence the deep circulation. The geostrophic transport for the narrow branch of current having the highest CFC concentration, which transits the region and continues equatorward adjacent to the western boundary, is 31 Sv (Sv -10(6) m(3) s(-1)) below 6 degrees C. A cyclonic gyre with one or more embedded gyres extends offshore of the narrow boundary current out to about 74 degrees W transporting 12 Sv of water with intermediate CFC concentrations. Farther offshore, a broad band of southward flow contributes an additional 16 Sv of water with considerably lower CFC: concentrations. Thus there is a total deep (<6 degrees C) equatorward transport through the study area along the western boundary of 47 Sv at 24 degrees N. The layer containing the shallower CFC core (4 degrees-6 degrees C) appears to be less constrained by the bottom topography. Within this temperature layer, one current branch with high CFC and low salinity flows southward along the Blake Escarpment. However, there is another branch of flow within this laver that forms an extended zonal high CFC and high salinity distribution from the eastern to the western bounds of the study region. This second branch apparently originates in the Gulf Stream recirculation and carries the higher salinity influence of the Mediterranean Water. C1 UNIV MIAMI, ROSENSTIEL SCH MARINE & ATMOSPHER SCI, MIAMI, FL 33149 USA. RP Johns, E (reprint author), NOAA, ATLANTIC OCEANOG & METEOROL LAB, 4301 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA. RI Johns, Elizabeth/I-3547-2013 OI Johns, Elizabeth/0000-0002-2181-5052 NR 43 TC 19 Z9 19 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD OCT PY 1997 VL 27 IS 10 BP 2187 EP 2208 DI 10.1175/1520-0485(1997)027<2187:DFATWB>2.0.CO;2 PG 22 WC Oceanography SC Oceanography GA YA958 UT WOS:A1997YA95800008 ER PT J AU Gu, DF Philander, SGH McPhaden, MJ AF Gu, DF Philander, SGH McPhaden, MJ TI The seasonal cycle and its modulation in the eastern tropical Pacific Ocean SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID EQUATORIAL PACIFIC; EL-NINO; VARIABILITY; ATMOSPHERE; 0-DEGREES; ATLANTIC; WAVES AB Data for the period from 1985 to 1993 from TAO moorings along 110 degrees W (5 degrees S-5 degrees N) and 140 degrees W (2 degrees S-9 degrees N) describe the vertical, meridional, and temporal structure of the seasonal cycle of several variables. The results have a number of interesting features. The amplitude of the seasonal cycle is relatively constant in the surface layers but varies considerably at the depth of the equatorial thermocline where it was small before 1989, large thereafter. Also, vertical seasonal movements of the thermocline have little effect on sea surface temperatures. These seasonal variations are consistent with a westward propagating coupled ocean-atmosphere mode in the surface layers. Conversely, the low-frequency modulation of the seasonal cycle in the thermocline is associated with changes in the seasonal cycle of the zonal wind in the central and western tropical Pacific and might be attributable to equatorial Kelvin waves forced resonantly by the surface winds. C1 PRINCETON UNIV,PROGRAM ATMOSPHER & OCEAN SCI,PRINCETON,NJ 08544. NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. RI McPhaden, Michael/D-9799-2016 NR 25 TC 15 Z9 15 U1 0 U2 4 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 OCT PY 1997 VL 27 IS 10 BP 2209 EP 2218 DI 10.1175/1520-0485(1997)027<2209:TSCAIM>2.0.CO;2 PG 10 WC Oceanography SC Oceanography GA YA958 UT WOS:A1997YA95800009 ER PT J AU vanMeurs, P Niiler, PP AF vanMeurs, P Niiler, PP TI Temporal variability of the large-scale geostrophic surface velocity in the northeast Pacific SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID LAGRANGIAN DRIFTERS; OCEAN; CIRCULATION; MOTIONS; FLOW AB from Argos-tracked mixed layer drifters in fall and winter 1987 (49 drifters) and 1989 (16 drifters) are used to investigate the differences in the large-scale surface velocity and eddy activity in the northeast Pacific. The velocities were corrected for wind-induced slippage and corrected for wind-driven (Ekman) flow by matching an Ekman model to the observed currents. The model, which explains 15%-30% of the variance, indicates that the currents are at 60 degrees ta the right of the wind. The magnitude of the currents is 30% of the magnitude of the wind stress. In 1987-88, the geostrophic motion in the region from 46.5 degrees to 48.5 degrees M, 142 degrees to 133 degrees W was characterized by an eastward flow of 0.9 (+/-0.4) cm s(-1) and a northward flow of 0.7 (+/-0.4) cm s(-1). In 1989-90, for the same region, the geostrophic eastward component was 3.8 (+/-0.5) cm s(-1). more than four times as large as in 1987-88, and the northward component was 0.3 (+/-0.5) cm s(-1). In this region ageostrophic contributions to the velocities are small. In 1987-88 the drifter tracks reveal evidence of the presence of several persistent. warm core mesoscale eddies. In 1989-90 there is no evidence of any significant eddy activity. The mean speed of the drifters in 1987-88 was 7.0 (+/-0.3) cm s(-1) and in 1989-90 was 6.5 (+/-0.4) cm s(-1). So, although the average speed is the samel drifters in 1987-88 take a longer time to travel eastward because of the significant north-south excursions due to the mesoscale eddies. Data from two drifter experiments have shown that the variability of mesoscale eddies ran result in large interannual differences in estimates of mean velocity. C1 UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093. RP vanMeurs, P (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,REPM,7600 SAND POINT WAY NE,BIN C15700-BLDG 3,SEATTLE,WA 98115, USA. NR 14 TC 12 Z9 12 U1 1 U2 1 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 OCT PY 1997 VL 27 IS 10 BP 2288 EP 2297 DI 10.1175/1520-0485(1997)027<2288:TVOTLS>2.0.CO;2 PG 10 WC Oceanography SC Oceanography GA YA958 UT WOS:A1997YA95800014 ER PT J AU Spinu, I McKenna, GB AF Spinu, I McKenna, GB TI Physical aging of thin films of nylon and PET SO JOURNAL OF PLASTIC FILM & SHEETING LA English DT Article DE nylon 66 film; PET film; physical aging; creep; superposition ID SEMI-CRYSTALLINE POLYMERS; SEMICRYSTALLINE POLYMERS; MECHANICAL-BEHAVIOR; CREEP-RUPTURE; EPOXY GLASSES; TERM CREEP; POLY(ETHYLENE-TEREPHTHALATE); PREDICTION; PMMA AB The physical aging of nylon 66 and PET [poly(ethylene terephthalate)] films as a function of aging temperature, magnitude of applied stress, and aging time was investigated. One hundred micron thick nylon films and 5 mu m and 190 mu m films of PET were investigated in temperature ranges that extended from below the glass transition temperature to well above it. Creep experiments were performed to probe the evolution of the material response after quenching from a "stabilization" temperature to the aging temperature and it was found that the classical time-aging time superposition could be applied to both the nylon and PET materials in the temperature range from 25 to 60 degrees C. The behaviors at higher temperature could not be superposed using time-aging time shifting. The rate of aging of the nylon films was found to be significantly different from that found for a similar nylon that had been injection molded. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 39 TC 10 Z9 10 U1 0 U2 6 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 8756-0879 J9 J PLAST FILM SHEET JI J. Plast. Film Sheeting PD OCT PY 1997 VL 13 IS 4 BP 311 EP 326 PG 16 WC Materials Science, Coatings & Films SC Materials Science GA YY398 UT WOS:000072143100004 ER PT J AU Godart, C Alleno, E Tominez, E Gupta, LC Nagarajan, R Hossain, Z Lynn, JW Bonville, P Hodges, JA Sanchez, JP Felner, I AF Godart, C Alleno, E Tominez, E Gupta, LC Nagarajan, R Hossain, Z Lynn, JW Bonville, P Hodges, JA Sanchez, JP Felner, I TI Some chemical and physical properties of quaternary borocarbides SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article; Proceedings Paper CT 12th International Symposium on Boron, borides, and Related Compounds CY AUG 25-30, 1996 CL VIENNA, AUSTRIA ID PD-B-C; PALLADIUM BORIDE CARBIDE; MAGNETIC-PROPERTIES; T-C; SUPERCONDUCTIVITY; PHASE; SYSTEM; YNI2B2C; EARTH; SUBSTITUTION AB The recent discovery of superconductivity (SC) in the quaternary borocarbide system Y-Ni-B-C has opened up a new area of research in SC. SC mainly occurs only for the end members of rare earths (R) and magnetism and SC coexist when R is a magnetic ion (Ho, Er, Tm, and later in Dy). We will discuss and give some new results on the effects of annealing on the impurity phases and on low Fe doping rates on the coexistence between SC and magnetism in materials with R = Ho. Superconductivity has been reported in Y-Pd-B-C system with a T-c (22 to 23 K) higher than the record for bulk intermetallics. The composition and structure of the SC phase(s) is still a topic of controversy that we will briefly discuss, giving new results. (C) 1997 Academic Press. C1 TIFR,BOMBAY 400001,MAHARASHTRA,INDIA. NIST,GAITHERSBURG,MD 20899. CEA,F-91191 GIF SUR YVETTE,FRANCE. CEA,F-38054 GRENOBLE,FRANCE. HEBREW UNIV JERUSALEM,IL-91905 JERUSALEM,ISRAEL. RP Godart, C (reprint author), CNRS,LCMSTR,UPR 209,F-92195 MEUDON,FRANCE. NR 55 TC 9 Z9 9 U1 1 U2 2 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 OCT PY 1997 VL 133 IS 1 BP 169 EP 177 DI 10.1006/jssc.1997.7334 PG 9 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA YG966 UT WOS:A1997YG96600034 ER PT J AU White, GS Braun, LM AF White, GS Braun, LM TI Strength vs stressing rate and indentation crack growth behavior of indium(III) phosphide SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CORROSION AB Susceptibility of InP to environmentally enhanced crack growth behavior was investigated in water and in 50% relative humidity by strength vs stressing rate and indentation crack length measurements. Statistical analysis indicated that, at the 95% confidence level, no environmentally enhanced fracture was detected for InP in liquid or gaseous water. RP White, GS (reprint author), NIST,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 11 TC 1 Z9 1 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 OCT PY 1997 VL 80 IS 10 BP 2699 EP 2701 PG 3 WC Materials Science, Ceramics SC Materials Science GA YB060 UT WOS:A1997YB06000031 ER PT J AU Zimmerman, MH Faber, KT Fuller, ER AF Zimmerman, MH Faber, KT Fuller, ER TI Forming textured microstructures via the gelcasting technique SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID POLE FIGURES AB Crystallographically textured samples of iron titanate were produced by gelcasting in the presence of a strong magnetic field. Texture was assessed by measuring X-ray pole figures on samples that were cast in different orientations relative to the applied field. Specimens in this study exhibit fiber-type texture, with the b-axes aligned parallel to the applied field. Peak texture strengths were on the order of 3 and 48 multiples of a random distribution (MRD) when processed in a 3.2 and 8.4 T magnetic field, respectively. This study shows that a combination of gelcasting with magnetic-field-assisted processing provides a convenient method for fabricating samples which can be used to study the role of crystallographic texture on the physical properties of polycrystalline ceramics, e.g., their elastic or fracture behavior. C1 NIST,DIV CERAM,GAITHERSBURG,MD 20899. RP Zimmerman, MH (reprint author), NORTHWESTERN UNIV,ROBERT R MCCORMICK SCH ENGN & APPL SCI,DEPT MAT SCI & ENGN,EVANSTON,IL 60208, USA. RI Faber, Katherine/B-6741-2009 NR 21 TC 33 Z9 33 U1 2 U2 5 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 1997 VL 80 IS 10 BP 2725 EP 2729 PG 5 WC Materials Science, Ceramics SC Materials Science GA YB060 UT WOS:A1997YB06000038 ER PT J AU Xiao, GY Parsons, JF Armstrong, RN Gilliland, GL AF Xiao, GY Parsons, JF Armstrong, RN Gilliland, GL TI Crystal structure of tetradeca-(3-fluorotyrosyl)-glutathione transferase SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; D-LACTATE DEHYDROGENASE; UNNATURAL AMINO-ACIDS; ESCHERICHIA-COLI; LIGAND-BINDING; DIHYDROFOLATE-REDUCTASE; 3-DIMENSIONAL STRUCTURE; MECHANISM; PROTEINS; 3-FLUOROTYROSINE C1 VANDERBILT UNIV,SCH MED,DEPT BIOCHEM,NASHVILLE,TN 37232. VANDERBILT UNIV,SCH MED,DEPT CHEM,NASHVILLE,TN 37232. VANDERBILT UNIV,SCH MED,CTR MOL TOXICOL,NASHVILLE,TN 37232. UNIV MARYLAND,MARYLAND BIOTECHNOL INST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NIST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NR 24 TC 19 Z9 19 U1 0 U2 1 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 OCT 1 PY 1997 VL 119 IS 39 BP 9325 EP 9326 DI 10.1021/ja972608m PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XY938 UT WOS:A1997XY93800048 ER PT J AU Bossart, GD Ewing, R Herron, AJ Gray, C Mase, B Decker, SJ Alexander, JW Altman, NH AF Bossart, GD Ewing, R Herron, AJ Gray, C Mase, B Decker, SJ Alexander, JW Altman, NH TI Immunoblastic malignant lymphoma in dolphins: histologic, ultrastructural, and immunohistochemical features SO JOURNAL OF VETERINARY DIAGNOSTIC INVESTIGATION LA English DT Article ID SIMIAN IMMUNODEFICIENCY VIRUS; BOTTLE-NOSED DOLPHINS; TURSIOPS-TRUNCATUS; LEUKEMIA; DISEASE C1 Univ Miami, Sch Med, Dept Pathol, Div Comparat Pathol, Miami, FL 33101 USA. Univ Miami, Sch Med, Dept Cell Biol & Anat, Miami, FL 33101 USA. Miami Seaquarium, Miami, FL 33149 USA. SE Fisheries Sci Ctr, Charleston Lab, Natl Marine Fisheries Serv, Charleston, SC 29422 USA. SE Fisheries Sci Ctr, Miami Lab, Natl Marine Fisheries Serv, Miami, FL 33149 USA. Oklahoma State Univ, Coll Vet Med, Stillwater, OK 74078 USA. RP Bossart, GD (reprint author), Univ Miami, Sch Med, Dept Pathol, Div Comparat Pathol, POB 016960 R-46, Miami, FL 33101 USA. NR 34 TC 13 Z9 13 U1 1 U2 1 PU AMER ASSOC VETERINARY LABORATORY DIAGNOSTICIANS INC PI TURLOCK PA PO BOX 1522, TURLOCK, CA 95381 USA SN 1040-6387 J9 J VET DIAGN INVEST JI J. Vet. Diagn. Invest. PD OCT PY 1997 VL 9 IS 4 BP 454 EP 458 PG 5 WC Veterinary Sciences SC Veterinary Sciences GA ZB339 UT WOS:000072461600027 PM 9376447 ER PT J AU Lyons, ET DeLong, RL Melin, SR Tolliver, SC AF Lyons, ET DeLong, RL Melin, SR Tolliver, SC TI Uncinariasis in northern fur seal and California sea lion pups from California SO JOURNAL OF WILDLIFE DISEASES LA English DT Article DE California sea lion; Callorhinus ursinus; hookworm intensity; northern fur seal; prevalence; pup mortality; Uncinaria spp.; Zalophus californianus AB Northern fur seal (Callorhinus ursinus) (n = 25) and California sea lion (Zalophus californianus) (n = 53) pups, found dead on rookeries on San Miguel Island (California, USA), were examined for adult Uncinaria spp. Prevalence of these nematodes was 96% in fur seal pups and 100% in sea lion pups. Mean intensity of Uncinaria spp, per infected pup was 643 in fur seals and 1,284 in sea lions. Eggs of Uncinaria spp. from dead sea lion pups underwent embryonation in an incubator; development to the free-living third stage larva occurred within the egg.; This study provided some specific information on hookworm infections in northern fur seal and California sea lion pups on San Miguel Island. High prevalence rate of Uncinaria spp. in both species of pinnipeds was documented and much higher numbers (2X) of hookworms were present in sea lion than fur seal pups. C1 NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,NATL MARINE MAMMAL LAB,SEATTLE,WA 98115. RP Lyons, ET (reprint author), UNIV KENTUCKY,DEPT VET SCI,GLUCK EQUINE RES CTR,LEXINGTON,KY 40546, USA. NR 15 TC 24 Z9 24 U1 1 U2 4 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 OCT PY 1997 VL 33 IS 4 BP 848 EP 852 PG 5 WC Veterinary Sciences SC Veterinary Sciences GA YD641 UT WOS:A1997YD64100018 PM 9391970 ER PT J AU McFee, W Root, H Friedman, R Zolman, E AF McFee, W Root, H Friedman, R Zolman, E TI A stingray spine in the scapula of a bottlenose dolphin SO JOURNAL OF WILDLIFE DISEASES LA English DT Article DE bottlenose dolphin; case report; scapula; stingray spine; toxins; Tursiops truncatus AB A stingray spine was found lodged in the scapula of a deceased 272 cm, male bottlenose dolphin (Tursiops truncatus) from South Carolina (USA) following skeletal preparation, nearly 6 mo after necropsy. No external puncture wound, internal bruising, or laceration of muscle tissue surrounding the scapula was evident during necropsy of the animal. Implantation of the spine did not appear to be related to the death of the dolphin, but probably occurred at an early age. Abnormal development of bone surrounding the spine resulted in the formation of a cavity at the wound site. Two mechanisms were considered as contributors for the cavity formation. These were the mechanical action of the spine stimulating the body's defense System for managing foreign objects, and the release of potent toxins from the spine sheath. C1 MED UNIV S CAROLINA,MOL & CELLULAR BIOL & PATHOBIOL GRAD PROGRAM,CHARLESTON,SC 29425. MED UNIV S CAROLINA,DEPT ORTHOPAED SURG,CHARLESTON,SC 29425. RP McFee, W (reprint author), NOAA,DEPT COMMERCE,NATL MARINE FISHERIES SERV,CHARLESTON LAB,219 FT JOHNSON RD,CHARLESTON,SC 29412, USA. NR 13 TC 5 Z9 6 U1 0 U2 0 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 OCT PY 1997 VL 33 IS 4 BP 921 EP 924 PG 4 WC Veterinary Sciences SC Veterinary Sciences GA YD641 UT WOS:A1997YD64100035 PM 9391987 ER PT J AU Hanley, HJM Muzny, CD Butler, BD AF Hanley, HJM Muzny, CD Butler, BD TI Surfactant adsorption on a clay mineral: Application of radiation scattering SO LANGMUIR LA English DT Article ID ANGLE NEUTRON-SCATTERING; COLLOIDAL PROPERTIES; ORGANIC-COMPOUNDS; LIGHT-SCATTERING; SUSPENSIONS; DISPERSIONS; SORPTION; LAPONITE; MONTMORILLONITE; COMPLEXES AB Aqueous mixtures of the synthetic clay mineral Laponite and cetyltrimethylammonium bromide (CTAB) in dilute suspension have been investigated by small-angle neutron scattering (SANS) and dynamic light scattering (DLS). The SANS intensity pattern from the suspension of the pure clay is consistent with that from disks or platelets with diameters of about 30 nm. After addition of CTAB to the clay suspensions, CTAB adsorbs on the face of the clay platelets by cationic exchange and the resulting complex contains excess CTAB in an amount corresponding to about four multiples of the clay's cation exchange capacity (CEC). Contrast matching by isotopic substitution in the solvent indicates that the CTAB/clay complex retains a disk morphology, even if the CTAB in the aqueous medium is in considerable excess. Analyses of the DLS data are interpreted to indicate two possible stable clay platelet configurations in the suspensions-free clay platelets or clay platelets with CTAB adsorbed in an amount above the CEC and presumably enough to form a stable surfactant bilayer. The effect of CTAB concentration in solution on the aggregation of the clay and its subsequent redispersion is reported, and the influence of clay on CTAB micelle formation is also discussed briefly. RP Hanley, HJM (reprint author), NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,BOULDER,CO 80303, USA. NR 51 TC 45 Z9 46 U1 3 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD OCT 1 PY 1997 VL 13 IS 20 BP 5276 EP 5282 DI 10.1021/la962048p PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA XZ089 UT WOS:A1997XZ08900011 ER PT J AU Thirtle, PN Li, ZX Thomas, RK Rennie, AR Satija, SK Sung, LP AF Thirtle, PN Li, ZX Thomas, RK Rennie, AR Satija, SK Sung, LP TI Structure of nonionic surfactant layers adsorbed at the solid/liquid interface on self-assembled monolayers with different surface functionality: A neutron reflection study SO LANGMUIR LA English DT Article ID AQUEOUS PERMANGANATE INTERACTION; PENETRATION-CONTROLLED REACTIONS; GLYCOL MONODODECYL ETHER; LONG-CHAIN SURFACTANTS; SILICA WATER INTERFACE; ADSORPTION; MULTILAYER; FILMS AB The adsorption of a series of nonionic surfactants, CnH2n+1(OC2H4)(m)OH (CnEm), from aqueous solution onto a self-assembled monolayer (SAM) before and after chemical modification has been studied by neutron reflection. On a SAM consisting of a layer of undecenyl trichlorosilane with the ethylenic group at the aqueous interface all the surfactants adsorbed to form a monolayer whose thickness compared with the length of the molecule suggests that the molecules are tilted at angles in the region of 60 degrees away from the surface normal. There was some penetration of the SAM layer by the alkyl chains of the surfactants. When the SAM was hydroxylated, the pattern of adsorption was found to be quite different and, for all the surfactants, the layer was only about 4 Angstrom thick with a segmental surface density constant within experimental error, and there was no penetration of the SAM. The structure of this layer is attributed to hydrogen bonding between the ethylene glycol groups in the surfactant and the OH groups on the surface of the SAM. For comparison the adsorption of the same set of surfactants was studied on the bare silica surface. In all cases the adsorption was in the form of a defective bilayer, quite different again from the adsorption pattern on the two SAMs. C1 UNIV OXFORD,PHYS & THEORET CHEM LAB,OXFORD OX1 3QZ,ENGLAND. UNIV CAMBRIDGE,CAVENDISH LAB,CAMBRIDGE CB3 0HE,ENGLAND. NIST,CTR NEUTRON RES,GAITHERSBURG,MD 20899. NR 26 TC 45 Z9 45 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD OCT 1 PY 1997 VL 13 IS 20 BP 5451 EP 5458 DI 10.1021/la970428k PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA XZ089 UT WOS:A1997XZ08900036 ER PT J AU Han, CC AF Han, CC TI Shear mixing and phase diagram shift of polymer blends SO MACROMOLECULAR SYMPOSIA LA English DT Article; Proceedings Paper CT IUPAC International Symposium on Macromolecular Condensed State (ISMCS 96) CY AUG 20-25, 1996 CL BEIJING, PEOPLES R CHINA SP Int Union Pure & Appl Chem, State Sci & Technol Commiss China, Chinese Acad Sci, Chinese Chem Soc, Natl Nat Sci Fdn China ID SPINODAL DECOMPOSITION; CRITICAL FLUIDS; FLOW; MIXTURES AB For a low molecular weight polystyrene/polybutadiene blend, the effect of shear on the suppressing of critical fluctuations and the critical temperature has been studied and is in good agreement with the predictions of Onuki and Kawasaki. By assuming the symmetry of this critical scaling into the two phase region, together with the Taylor theory, the observed (phase separated) droplet break-up and the formation of string pattern can be explained. The exact shear dependence of T-c(gamma) over dot can be obtained by the use of the fluorescence microscope under steady shear. RP Han, CC (reprint author), NATL INST STAND & TECHNOL,DIV POLYMER,GAITHERSBURG,MD 20899, USA. NR 17 TC 2 Z9 2 U1 0 U2 1 PU HUTHIG & WEPF VERLAG PI BASEL PA AUF DEM WOLF 4, CH-4052 BASEL, SWITZERLAND SN 1022-1360 J9 MACROMOL SYMP JI Macromol. Symp. PD OCT PY 1997 VL 124 BP 111 EP 120 DI 10.1002/masy.19971240113 PG 10 WC Polymer Science SC Polymer Science GA YJ105 UT WOS:A1997YJ10500012 ER PT J AU Baumgartner, MF AF Baumgartner, MF TI The distribution of Risso's dolphin (Grampus griseus) with respect to the physiography of the northern Gulf of Mexico SO MARINE MAMMAL SCIENCE LA English DT Article DE Risso's dolphin; Grampus griseus; Gulf of Mexico; habitat; physiography; depth; depth gradient ID NORTHEASTERN UNITED-STATES; SHELF-BREAK FRONT; CONTINENTAL-SHELF; EASTERN GULF; LOOP CURRENT; NOVA-SCOTIA; OF-MEXICO; CETACEANS; SOUTH; PATTERNS AB The distribution of Risso's dolphin (Grampus griseus) was examined with respect to two physiographic variables, water depth and depth gradient (sea floor slope), in the northern Gulf of Mexico, using shipboard and aerial survey data collected from 1992 to 1994. Univariate chi(2) analyses demonstrated that Risso's dolphins are distributed non-uniformly with respect to both depth and depth gradient. A bivariate analysis of the shipboard data indicated that Risso's dolphins utilize the steep sections of the upper continental slope in the northern Gulf of Mexico. This narrow core habitat is in waters bounded by the 350-m and 975-m isobaths with depth gradients greater than 24 m per 1.1 km and consists of only 2% of the surface area of the entire Gulf of Mexico. Sighting rates inside this region were nearly 5 and 6 times the average for the shipboard and aerial surveys, respectively. Of the groups sighted outside this region, 40% (shipboard) and 73% (aerial) were encountered within 5 km of it. Since it is unlikely that the physiography alone can attract dolphins, oceanographic mechanisms that may concentrate prey along the steep upper continental slope are discussed. The implications of this distribution, including potential prey species, foraging strategies, and impacts of proposed mineral exploration and development, are also considered. C1 NOAA,SE FISHERIES SCI CTR,NATL MARINE FISHERIES SERV,STENNIS SPACE CTR,MS 39529. NR 47 TC 68 Z9 80 U1 1 U2 13 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 OCT PY 1997 VL 13 IS 4 BP 614 EP 638 DI 10.1111/j.1748-7692.1997.tb00087.x PG 25 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA YA660 UT WOS:A1997YA66000005 ER PT J AU Logan, NG Smith, T AF Logan, NG Smith, T TI A hand-held, pen-based computer system for marine mammal sighting surveys SO MARINE MAMMAL SCIENCE LA English DT Article RP Logan, NG (reprint author), NATL MARINE FISHERIES SERV,166 WATER ST,WOODS HOLE,MA 02543, USA. NR 6 TC 5 Z9 5 U1 0 U2 1 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 OCT PY 1997 VL 13 IS 4 BP 694 EP 700 DI 10.1111/j.1748-7692.1997.tb00092.x PG 7 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA YA660 UT WOS:A1997YA66000010 ER PT J AU Reeves, RR Perrin, WF Jefferson, TA AF Reeves, RR Perrin, WF Jefferson, TA TI James Stephen Leatherwood - 1944-1997 SO MARINE MAMMAL SCIENCE LA English DT Item About an Individual C1 SW FISHERIES SCI CTR,LA JOLLA,CA 92038. NR 1 TC 0 Z9 0 U1 0 U2 1 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 OCT PY 1997 VL 13 IS 4 BP 721 EP 725 PG 5 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA YA660 UT WOS:A1997YA66000015 ER PT J AU Barnett, TC Kirov, SM Strom, MS Sanderson, K AF Barnett, TC Kirov, SM Strom, MS Sanderson, K TI Aeromonas spp. possess at least two distinct type IV pilus families SO MICROBIAL PATHOGENESIS LA English DT Article DE Aeromonas; type IV pili; pilus biogenesis ID POSSIBLE COLONIZATION FACTOR; ESCHERICHIA-COLI; VIBRIO-CHOLERAE; HYDROPHILA; SOBRIA; PURIFICATION; BIOGENESIS; AEROLYSIN; PROTEINS; ADHESION AB Type IV pill have been purified from strains of most of the Aeromonas species associated with gastroenteritis (A. veronii biovar sobria, A. hydrophila, A. trota and A. caviae). They appear to be a related family (molecular mass of pilin 19 to 23 kDa) with a tendency to bundle-formation. Hence, we have designated them 'bundle-forming pili' (Bfp). A type IV pilus biogenesis gene cluster (tapABCD) recently cloned from a strain of A. hydrophila, however, encoded a 17 kDa pilin which differed significantly in its N-terminal amino acid sequence from the Bfp pilins. This paper describes the cloning of part (tapA and similar to 20% of tapB) of a homologous pilin gene cluster from a Bfp-positive strain of A. veronii biovar sobria, and presents evidence that the entire pilin gene cluster (tapABCD) is present in this strain. The predicted N-terminal amino acid sequence of the pilin encoded by the A. veronii biovar sobria tapA differed markedly from the corresponding sequence of its Bfp pilin, and those of the Bfp purified from other Aeromonas strains and species. Probing with tapA and tapD genes showed that these Bfp-positive Aeromonas strains also possessed the Tap gene cluster. TapA proteins of A. veronii biovar sobria and A. hydrophila shared 53% identity and 63% homology. We conclude that Aeromonas species are potentially able to express at least two distinct families of type IV pili (Bfp and Tap). (C) 1997 Academic Press Limited. C1 UNIV TASMANIA,DIV PATHOL,HOBART,TAS 7001,AUSTRALIA. NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,US DEPT COMMERCE,SEATTLE,WA 98112. RI Barnett, Tim/G-2155-2011 NR 29 TC 25 Z9 26 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0882-4010 J9 MICROB PATHOGENESIS JI Microb. Pathog. PD OCT PY 1997 VL 23 IS 4 BP 241 EP 247 DI 10.1006/mpat.1997.0152 PG 7 WC Immunology; Microbiology SC Immunology; Microbiology GA YB290 UT WOS:A1997YB29000006 PM 9344785 ER PT J AU Juroshek, JR AF Juroshek, JR TI A direct calibration method for measuring equivalent source mismatch SO MICROWAVE JOURNAL LA English DT Article AB A new method for measuring the equivalent source mismatch of a three-port device is described. Equivalent source mismatch measurement are required when three-port devices, such as directional coupler, power dividers and power splitters, are used for power measurements or for calibrating other power sensors. This direct calibration method uses conventional vector network analyzer (VNA) one-port calibration techniques to determine the equivalent source mismatch of the three-port device. Measurements are shown for both a 2 to 18 GHz directional bridge and a 2 to 50 GHz directional coupler. The accuracy of these measurements is similar to the accuracy normally obtained from measurements of equivalent source mismatch inside a VNA. RP Juroshek, JR (reprint author), NIST,BOULDER,CO, USA. NR 9 TC 8 Z9 9 U1 0 U2 0 PU HORIZON HOUSE PUBLICATIONS INC PI NORWOOD PA 685 CANTON ST, NORWOOD, MA 02062 SN 0192-6225 J9 MICROWAVE J JI Microw. J. PD OCT PY 1997 VL 40 IS 10 BP 106 EP & PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA YB110 UT WOS:A1997YB11000019 ER PT J AU OCorryCrowe, GM Suydam, RS Rosenberg, A Frost, KJ Dizon, AE AF OCorryCrowe, GM Suydam, RS Rosenberg, A Frost, KJ Dizon, AE TI Phylogeography, population structure and dispersal patterns of the beluga whale Delphinapterus leucas in the western Nearctic revealed by mitochondrial DNA SO MOLECULAR ECOLOGY LA English DT Review DE dispersal; beluga whale; mitochondrial DNA; population structure; mating system ID ATLANTIC HUMPBACK WHALES; TURTLE CHELONIA-MYDAS; EASTERN HUDSON-BAY; WHITE WHALES; GENE FLOW; MEGAPTERA-NOVAEANGLIAE; GEOGRAPHIC SUBDIVISION; MATING SYSTEMS; CONTROL-REGION; UNGAVA BAY AB The recent evolutionary history, population structure and movement patterns of beluga whales in the western Nearctic were inferred from an analysis of mitochondrial DNA control region sequence variation of 324 whales from 32 locations representing five summer concentration areas in Alaska and north-west Canada. Phylogenetic relationships among haplotypes were inferred from parsimonious networks, and genetic subdivision was examined using haplotypic frequency-based indices and an analysis of variance method modified for use with interhaplotypic distance data. MtDNA relationships were characterized by a series of star-like phylogenies which, when viewed in conjunction with information on haplotype frequency and distribution, suggested a rapid radiation of beluga whales into the western Nearctic following the Pleistocene, and an early divergence of the Beaufort Sea from the Chukchi and Bering Seas subpopulations. Overall nucleotide diversity was low (0.51%) yet all major summering concentrations were significantly differentiated (Phi(ST) = 0.33) from one another. Stratification of samples by gender and age from the three northernmost subpopulations suggested that female cohorts from neighbouring subpopulations were more differentiated than males. Further stratification of adult animals by age revealed that older adults were substantially less subdivided among locations than younger adults, particularly for males, suggesting that dispersal, although limited, is biased toward older adult males. Overall, the patterns of mtDNA variation in beluga whales indicated that the summering concentrations are demographically, if not phyletically distinct. Population structure appears to be maintained primarily by natal homing behaviour, while asymmetries in dispersal may be associated with the type of mating system. C1 N SLOPE BOROUGH DEPT WILDLIFE MANAGEMENT,BARROW,AK 99723. ALASKA DEPT FISH & GAME,FAIRBANKS,AK 99701. RP OCorryCrowe, GM (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,POB 271,LA JOLLA,CA 92038, USA. NR 115 TC 126 Z9 137 U1 2 U2 33 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD OCT PY 1997 VL 6 IS 10 BP 955 EP 970 DI 10.1046/j.1365-294X.1997.00267.x PG 16 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA YB673 UT WOS:A1997YB67300006 ER PT J AU Pu, ZX Kalnay, E Sela, J Szunyogh, I AF Pu, ZX Kalnay, E Sela, J Szunyogh, I TI Sensitivity of forecast errors to initial conditions with a quasi-inverse linear method SO MONTHLY WEATHER REVIEW LA English DT Article ID NATIONAL-METEOROLOGICAL-CENTER; VARIATIONAL DATA ASSIMILATION; ANALYSIS SYSTEM; NMC; MODEL; PREDICTABILITY; PERTURBATIONS; GROWTH AB A quasi-inverse linear method has been developed to study the sensitivity of forecast errors to initial conditions for the National Centers for Environmental Prediction's (NCEP) global spectral model. The inverse is approximated by running the tangent linear model (TLM) of the nonlinear forecast model with a negative time step, but reversing the sign of friction and diffusion terms, in order to avoid the computational instability that would be associated with these terms if they were run backward. As usually done using the adjoint model integrations, the quasi-inverse TLM is started at the time of the verified forecast error and integrated backward to the corresponding initial time. First, a numerical experiment shows that this quasi-inverse linear estimation is able to trace back the differences between two perturbed forecasts from the NCEP ensemble forecasting system and recover with good accuracy the known difference between the two forecasts at the initial time. This result shows that both the linear estimation and the quasi-inverse linear estimation are quite close to the nonlinear evolution of the perturbation in the nonlinear forecast model, suggesting that it should be possible to apply the method to the study of the sensitivity of forecast errors to initial conditions. The authors then calculate the perturbation field at the initial time (estimate the initial error) by tracing back a 1-day forecast error using the TLM quasi-inverse estimation. As could be expected from the previous experiment, when the estimated error is subtracted from the original analysis, the new initial conditions lead to an almost perfect 1-day forecast. The forecasts beyond the first day are also considerably improved, indicating that the initial conditions have indeed been improved. In the remainder of the paper, this quasi-inverse linear method is compared with the adjoint sensitivity method (Rabier et al., Pu et al.) for medium-range weather forecasting. The authors find that both methods are able to trace back the forecast error to perturbations that improve the initial conditions. However, the forecast improvement obtained by the quasi-inverse linear method is considerably better than that obtained with a single adjoint iteration and similar to the one obtained using five iterations of the adjoint method, even though each adjoint iteration requires at least twice the computer resources of the quasi inverse TLM estimation. Whereas the adjoint forecast sensitivities are closely related to singular vectors, the quasi-inverse linear perturbations are associated with the bred (Lyapunov) vectors used for ensemble forecasting at NCEP (Toth and Kalnay). The features of the two types of perturbations are also compared in this study. Finally, the possibility of the use of the sensitivity perturbation to improve future forecast skill is discussed, and preliminary experiments encourage further testing of this rather inexpensive method for possible operational use. The model used in this study is the NCEP operational global spectral model at a resolution of T62/L28. The corresponding TLM, and its adjoint, are based on an adiabatic version of the model but include both horizontal and vertical diffusion. C1 NATL CTR ENVIRONM PREDICT, ENVIRONM MODELING CTR, WASHINGTON, DC USA. LANZHOU UNIV, LANZHOU 730000, PEOPLES R CHINA. RI Kalnay, Eugenia/F-4393-2010; Szunyogh, Istvan/G-9248-2012; OI Kalnay, Eugenia/0000-0002-9984-9906 NR 49 TC 56 Z9 63 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD OCT PY 1997 VL 125 IS 10 BP 2479 EP 2503 DI 10.1175/1520-0493(1997)125<2479:SOFETI>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XZ561 UT WOS:A1997XZ56100006 ER PT J AU Simpson, J Ritchie, E Holland, GJ Halverson, J Stewart, S AF Simpson, J Ritchie, E Holland, GJ Halverson, J Stewart, S TI Mesoscale interactions in tropical cyclone genesis SO MONTHLY WEATHER REVIEW LA English DT Article ID WARM-CORE VORTEX; SCALE VORTICES; EVOLUTION; DYNAMICS; SYSTEMS; REGION AB With the multitude of cloud clusters over tropical oceans, it has been perplexing that so few develop into tropical cyclones. The authors postulate that a major obstacle has been the complexity of scale interactions, particularly those on the mesoscale, which have only recently been observable. While there are well-known climatological requirements, these are by no means sufficient. A major reason for this rarity is the essentially stochastic nature of the mesoscale interactions that precede and contribute to cyclone development. Observations exist for only a few forming cases. In these, the moist convection in the preformation environment is organized into mesoscale convective systems, each of which have associated mesoscale potential vortices in the midlevels. Interactions between these systems may lead to merger, growth to the surface, and development of both the nascent eye and inner rainbands of a tropical cyclone. The process is essentially stochastic, but the degree of stochasticity can be reduced by the continued interaction of the mesoscale systems or by environmental influences. For example a monsoon trough provides a region of reduced deformation radius, which substantially improves the efficiency of mesoscale vortex interactions and the amplitude of the merged vortices. Further, a strong monsoon trough provides a vertical wind shear that enables long-lived midlevel mesoscale vortices that are able to maintain, or even redevelop, the associated convective system. The authors develop this hypothesis by use of a detailed case study of the formation of Tropical Cyclone Oliver observed during TOGA COARE (1993). In this case, two dominant mesoscale vortices interacted with a monsoon trough to separately produce a nascent eye and a major rainband. The eye developed on the edge of the major convective system, and the associated atmospheric warming was provided almost entirely by moist processes in the upper atmosphere, and by a combination of latent heating and adiabatic subsidence in the lower and middle atmosphere. The importance of mesoscale interactions is illustrated further by brief reference to the development of two typhoons in the western North Pacific. C1 USN,POSTGRAD SCH,DEPT METEOROL,MONTEREY,CA 93943. BUR METEOROL RES CTR,MELBOURNE,FL. NOAA,NATL WEATHER SERV,NEXRAD OSF OTB,NORMAN,OK. RP Simpson, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EARTH SCI DIRECTORATE,CODE 912,GREENBELT,MD 20771, USA. RI Ritchie, Elizabeth/B-4232-2016 OI Ritchie, Elizabeth/0000-0002-3413-5830 NR 40 TC 144 Z9 162 U1 1 U2 19 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 OCT PY 1997 VL 125 IS 10 BP 2643 EP 2661 DI 10.1175/1520-0493(1997)125<2643:MIITCG>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XZ561 UT WOS:A1997XZ56100015 ER PT J AU Munitz, A Kimmel, G Rawers, JC Fields, RJ AF Munitz, A Kimmel, G Rawers, JC Fields, RJ TI Ball milling induced bct phase formation in iron and iron alloys SO NANOSTRUCTURED MATERIALS LA English DT Article ID FE POWDER AB A variety of attritor ball milled Fe and Fe alloy powders, processed in an argon or a nitrogen environment, were studied using X-ray diffraction techniques. Broadened XRD spectra were obtained due to severe plastic deformation during ball milling. The broadening was non-uniform, displaying a systematic deviation from the average, with the (310) reflection peak being the broadest, and the (222) reflection peak being the sharpest. The systematic variation in broadening is interpreted as a tetragonal distortion. The tendency towards a tetragonal distortion occurred in all ball-milled samples. (C) 1998 Acta Metallurgica Inc. C1 Nucl Res Ctr Negev, IL-84190 Beer Sheva, Israel. US DOE, Albany, OR 97321 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Munitz, A (reprint author), Nucl Res Ctr Negev, POB 9001, IL-84190 Beer Sheva, Israel. NR 14 TC 13 Z9 13 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD OCT-NOV PY 1997 VL 8 IS 7 BP 867 EP 877 DI 10.1016/S0965-9773(98)00017-8 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA YZ598 UT WOS:000072270100010 ER PT J AU Arrivo, SM Kleiman, VD Dougherty, TP Heilweil, EJ AF Arrivo, SM Kleiman, VD Dougherty, TP Heilweil, EJ TI Broadband femtosecond transient infrared spectroscopy using a 256 x 256 element indium antimonide focal-plane detector SO OPTICS LETTERS LA English DT Article ID SPECTROMETER; EXCITATION AB Application and characterization of large-format IR focal-plane arrays as detectors for ultrafast, high-resolution IR spectroscopy are discussed. We also present generation of broadband IR probe-reference pulses by use of collinear non-phase-matched geometry and shot-to-shot dual-track normalization to obtain transient spectra from broadly absorbing hydrogen-bonded systems. As much as 400-cm(-1) -wide coverage with 15-cm(-1) FWHM spectral resolution and +/-6.4 x 10(-4) (Delta OD = 3 x 10(-4)) baseline standard deviation (+/-1 sigma) is demonstrated near 2.9 mu m. (C) 1997 Optical Society of America. C1 NATL INST STAND & TECHNOL,OPT TECHNOL DIV,GAITHERSBURG,MD 20899. UNIV CALIF LOS ANGELES,LOS ANGELES,CA. RI Kleiman, Valeria/H-7818-2013 OI Kleiman, Valeria/0000-0002-9975-6558 NR 13 TC 22 Z9 22 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD OCT 1 PY 1997 VL 22 IS 19 BP 1488 EP 1490 DI 10.1364/OL.22.001488 PG 3 WC Optics SC Optics GA XZ066 UT WOS:A1997XZ06600014 PM 18188277 ER PT J AU Povodyrev, AA Anisimov, MA Sengers, JV Sengers, JMHL AF Povodyrev, AA Anisimov, MA Sengers, JV Sengers, JMHL TI Vapor-liquid equilibria, scaling, and crossover in aqueous solutions of sodium chloride near the critical line SO PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS LA English DT Article ID CONSOLUTE CRITICAL PHENOMENA; CRITICAL-BEHAVIOR; SYSTEM NACL-H2O; CRITICAL REGION; THERMODYNAMIC BEHAVIOR; CRITICAL-POINTS; CRITICAL-TEMPERATURE; COEXISTENCE CURVE; FLUID MIXTURES; IONIC FLUIDS AB We have developed a crossover scaling model for describing the thermodynamic properties of near-critical binary fluids. We have validated this model for the vapor-liquid equilibrium properties of mixtures of methane and ethane. We then apply the model to a most intriguing binary fluid, namely aqueous solutions of sodium chloride, so as to describe densities and concentrations at vapor-liquid equilibrium and isochoric specific heat capacities in the one-phase region. The description shows crossover from asymptotic Ising-like critical behavior to classical (mean-field) behavior. As the salt concentration increases, the region of Ising behavior decreases, although pure classical behavior is never attained, We suggest that processes of association/dissociation may be responsible for the failure of the model to describe compositions of the vapor phase of the solutions at very low concentrations. C1 UNIV MARYLAND, INST PHYS SCI & TECHNOL, COLLEGE PK, MD 20742 USA. UNIV MARYLAND, DEPT CHEM ENGN, COLLEGE PK, MD 20742 USA. RUSSIAN ACAD SCI, INST OIL & GAS RES, MOSCOW 117917, RUSSIA. NIST, PHYS & CHEM PROPERTIES DIV, GAITHERSBURG, MD 20899 USA. NR 91 TC 22 Z9 22 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 EI 1873-2119 J9 PHYSICA A JI Physica A PD OCT 1 PY 1997 VL 244 IS 1-4 BP 298 EP 328 DI 10.1016/S0378-4371(97)00300-2 PG 31 WC Physics, Multidisciplinary SC Physics GA YA357 UT WOS:A1997YA35700025 ER PT J AU Djuric, N Chung, YS Wallbank, B Dunn, GH AF Djuric, N Chung, YS Wallbank, B Dunn, GH TI Measurement of light fragments in dissociative excitation of molecular ions: CD+ SO PHYSICAL REVIEW A LA English DT Article ID ELECTRON-IMPACT IONIZATION; EXCITED-STATES; CROSS-SECTION; RECOMBINATION; CH+; CURVES; BEAM AB A technique is described for detecting light fragment ions from dissociation of molecular ions. The crossed-beams method is adapted from a previous approach by implementation of ion optics, dispersion, and detection methods that are particularly focused on detection of the light ions from the breakup of heteronuclear molecular ions. Absolute cross sections as a function of interaction energy are reported for the process e + CD+ --> e + D+ + products, where the CD+ targets are characteristic of emission from a dischargeion source. C1 UNIV COLORADO,NATL INST STAND & TECHNOL,BOULDER,CO 80309. ST FRANCIS XAVIER UNIV,DEPT PHYS,ANTIGONISH,NS B2G 2W5,CANADA. RP Djuric, N (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 40 TC 17 Z9 17 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 OCT PY 1997 VL 56 IS 4 BP 2887 EP 2892 DI 10.1103/PhysRevA.56.2887 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA YA780 UT WOS:A1997YA78000056 ER PT J AU Lee, SH Broholm, C Collins, MF Heller, L Ramirez, AP Kloc, C Bucher, E Erwin, RW Lacevic, N AF Lee, SH Broholm, C Collins, MF Heller, L Ramirez, AP Kloc, C Bucher, E Erwin, RW Lacevic, N TI Less than 50% sublattice polarization in an insulating S=3/2 kagome antiferromagnet at T approximate to 0 SO PHYSICAL REVIEW B LA English DT Article ID SPIN-GLASS; TRIANGULAR-LATTICE; ORDER; FLUCTUATIONS; FRUSTRATION; JAROSITE; SRCR8GA4O19; MAGNETISM; DISORDER; DILUTION AB We have found weak long-range antiferromagnetic order in the quasi-two-dimensional insulating oxide KCr3(OD)(6)(SO4)(2) which contains Cr3+ S=3/2 ions on a kagome lattice. In a sample with approximate to 76% occupancy of the chromium sites the ordered moment is 1.1(3)mu(B) per chromium ion which is only one-third of the Neel value g mu(B)S=3 mu(B). The magnetic unit cell equals the chemical unit cell, a situation which is favored by interplane interactions. Gapless quantum spin fluctuations (Delta/k(B)<0.25 K) with a bandwidth of 60 K much greater than T-N=1.6 K are the dominant contribution to the spin correlation function S(Q,omega) in the ordered phase. C1 NIST,GAITHERSBURG,MD 20899. JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. MCMASTER UNIV,DEPT PHYS & ASTRON,HAMILTON,ON L8S 4M1,CANADA. AT&T BELL LABS,LUCENT TECHNOL,MURRAY HILL,NJ 07974. UNIV KONSTANZ,D-78434 CONSTANCE,GERMANY. RP Lee, SH (reprint author), UNIV MARYLAND,COLLEGE PK,MD 20742, USA. RI Broholm, Collin/E-8228-2011; Kloc, Christian/A-2255-2011 OI Broholm, Collin/0000-0002-1569-9892; NR 37 TC 67 Z9 67 U1 1 U2 9 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 OCT 1 PY 1997 VL 56 IS 13 BP 8091 EP 8097 DI 10.1103/PhysRevB.56.8091 PG 7 WC Physics, Condensed Matter SC Physics GA YD866 UT WOS:A1997YD86600063 ER PT J AU Ovchinnikov, YN Ivlev, BI Soulen, RJ Claassen, JH Fogle, WE Colwell, JH AF Ovchinnikov, YN Ivlev, BI Soulen, RJ Claassen, JH Fogle, WE Colwell, JH TI Temperature and magnetic field dependence of the induced magnetization in macroscopic samples due to the proximity effect SO PHYSICAL REVIEW B LA English DT Article ID CLAD NB; SILVER AB We have applied the Ginzburg-Landau equations to calculate the behavior of the diamagnetism of macroscopic samples consisting of a normal metal in contact with a superconductor. In particular, the calculation focuses on the temperature region above the superconductive transition temperature T-cN Of the normal metal. We have compared these calculations with experimental measurements of the temperature (0.006-1 K) and magnetic field (10(-9)-10(-6) T) dependence of the diamgetism for several samples of Be (T(cN)similar to 23 mK) and W (T(cN)similar to 15.5 mK) in contact with the superconductor Al (T-cS= 1.18 K). The agreement between the predictions and measurements is quite good and confirms the approach of using the Ginzburg-Landau model to calculate the proximity effect in macroscopic normal systems above their superconductive transitions. C1 USN, RES LAB, WASHINGTON, DC 20375 USA. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV MAT SCI, BERKELEY, CA 94720 USA. NIST, GAITHERSBURG, MD 20899 USA. RP Ovchinnikov, YN (reprint author), RUSSIAN ACAD SCI, LD LANDAU THEORET PHYS INST, KOSYGIN 2, MOSCOW 11733V, RUSSIA. NR 31 TC 5 Z9 5 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1997 VL 56 IS 14 BP 9038 EP 9051 DI 10.1103/PhysRevB.56.9038 PG 14 WC Physics, Condensed Matter SC Physics GA YC731 UT WOS:A1997YC73100075 ER PT J AU Rogers, CT Kirschenbaum, LS Beale, PD Russek, SE Sanders, SC AF Rogers, CT Kirschenbaum, LS Beale, PD Russek, SE Sanders, SC TI Observation of a fluctuation-enhanced magnetoresistance in Ni81F19/Ag multilayers at high current density SO PHYSICAL REVIEW B LA English DT Article ID GIANT MAGNETORESISTANCE; MAGNETIC MULTILAYERS; NIFE/AG MULTILAYERS; GMR MULTILAYERS; SENSORS; NOISE AB We report a correlation between peaks observed in the resistance versus applied magnetic field and low-frequency resistance noise for Ni81Fe19/Ag giant magnetoresistance systems with de bias current density above 10(6) A/cm(2). The magnetic noise has a 1/f-like spectrum and arises from time-dependent magnetic orientational fluctuations within the multilayer. The noise amplitude is strongly correlated with the observed magnetoresistance peaks. The data and a simple model for the fluctuations demonstrate the important role of fluctuations in determining magnetoresistance in such multilayer systems. C1 NATL INST STAND & TECHNOL,DIV ELECTROMAGNET TECHNOL,BOULDER,CO 80303. RP Rogers, CT (reprint author), UNIV COLORADO,DEPT PHYS,CONDENSED MATTER LAB,BOULDER,CO 80309, USA. NR 21 TC 0 Z9 0 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1997 VL 56 IS 14 BP R8503 EP R8506 PG 4 WC Physics, Condensed Matter SC Physics GA YC731 UT WOS:A1997YC73100013 ER PT J AU Migler, KB Bur, AJ AF Migler, KB Bur, AJ TI Measuring temperature profiles during polymer processing SO PLASTICS ENGINEERING LA English DT Article ID TRANSITION AB The authors describe a noninvasive method to measure profiles of polymer temperatures during processing. Monitoring key spectral features of a dopant fluorescent dye enables resin temperature to be determined. A focusing technique known as ''confocual fluorescent optics'' then allows the measuring df temperatures at the selected positions. RP Migler, KB (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0091-9578 J9 PLAST ENG JI Plast. Eng. PD OCT PY 1997 VL 53 IS 10 BP 27 EP & PG 4 WC Engineering, Chemical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA YC406 UT WOS:A1997YC40600013 ER PT J AU Parnas, RS Flynn, KM DalFavero, ME AF Parnas, RS Flynn, KM DalFavero, ME TI A permeability database for composites manufacturing SO POLYMER COMPOSITES LA English DT Article ID FLOW; LIQUID AB The National Institute of Standards and Technology (NIST) has developed a database containing a set of permeability results from carefully controlled measurements for both saturated and unsaturated flows in glass fabrics. The materials studied are fully documented in the database, and in some cases the material compressibility is also included. The experimental techniques used to generate the permeability data are briefly described and the included permeability data summarized. A sample search is illustrated to demonstrate the database user interface and the extent of the data documentation. C1 NIST,STAND REFERENCE DATA PROGRAM,GAITHERSBURG,MD 20899. RP Parnas, RS (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 17 TC 74 Z9 77 U1 1 U2 3 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0272-8397 J9 POLYM COMPOSITE JI Polym. Compos. PD OCT PY 1997 VL 18 IS 5 BP 623 EP 633 DI 10.1002/pc.10313 PG 11 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA YB615 UT WOS:A1997YB61500004 ER PT J AU Friedman, HL Johnson, RA Miller, B Salem, DR Parnas, RS AF Friedman, HL Johnson, RA Miller, B Salem, DR Parnas, RS TI Forced in-plane flow through complex deformable structures: Influence of an imposed curve SO POLYMER COMPOSITES LA English DT Article; Proceedings Paper CT 1995 ASME International Mechanical Engineering Congress and Exposition CY NOV 12-17, 1995 CL SAN FRANCISCO, CA SP Amer Soc Mech Engn ID MULTILAYER FIBER REINFORCEMENTS; INPLANE PERMEABILITY; FIBROUS NETWORKS; LIQUID; RESIN; PREFORMS; FLUIDS AB Forced in-plane flow of liquids through contiguous flat and curved regions of confined fabrics has been studied both as a general phenomenon and for predicting the flow of polymers during injection molding of monolithic composite structures with complex configurations, A controlled pressure difference is applied to drive the flow, while the mass flow rate is measured gravimetrically by Liquid/Air Displacement Analysis (LADA), Measurements have been carried out along fabric paths that are first vertical, then curved, and finally horizontal, Fluid flow equations have been adapted for analyzing flow in the flat sections, leading to the evaluation of permeability constants and capillary pressures. A saturated flow rate measured at constant hydrodynamic pressure is used to evaluate the overall permeability coefficient of the encapsulated fabric, Data are presented showing that permeability can be reduced as a consequence of flow through the curved region. C1 NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. RP Friedman, HL (reprint author), TRI PRINCETON,PRINCETON,NJ 08542, USA. NR 23 TC 5 Z9 5 U1 0 U2 0 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0272-8397 J9 POLYM COMPOSITE JI Polym. Compos. PD OCT PY 1997 VL 18 IS 5 BP 663 EP 671 DI 10.1002/pc.10318 PG 9 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA YB615 UT WOS:A1997YB61500009 ER PT J AU Matthews, GM Paasch, NN Achord, S McIntyre, KW Harmon, JR AF Matthews, GM Paasch, NN Achord, S McIntyre, KW Harmon, JR TI A technique to minimize the adverse effects associated with handling and marking salmonid smolts SO PROGRESSIVE FISH-CULTURIST LA English DT Article ID CHINOOK SALMON; ONCORHYNCHUS-TSHAWYTSCHA; STRESS; SURVIVAL AB A system that allows anesthetization of juvenile salmonids before netting during a handling and marking operation is described. Our purpose for designing the system was to reduce or minimize any debilitating effects associated with these activities. When compared with smelts handled and marked in the traditional manner, use of the technique resulted in a significant reduction in the mortality of naturally migrating smelts of spring-summer chinook salmon Oncorhynchus tshawytscha during a posthandling and marking seawater challenge performance test. The treatment resulted in lower, but not significantly lower, plasma cortisol levels; however, sample sizes may have been too small for statistical verification. With a little ingenuity, the technique should be adaptable to most smelt handling or marking operations. C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Coastal Zone & Estuarine Studies Div, Seattle, WA 98112 USA. RP Matthews, GM (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Coastal Zone & Estuarine Studies Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 7 TC 2 Z9 2 U1 0 U2 1 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0033-0779 J9 PROG FISH CULT JI Progress. Fish-Cult. PD OCT PY 1997 VL 59 IS 4 BP 307 EP 309 DI 10.1577/1548-8640(1997)059<0307:TNATTM>2.3.CO;2 PG 3 WC Fisheries SC Fisheries GA YM660 UT WOS:000071087000009 ER PT J AU Kamireddi, M Eisenstein, E Reddy, P AF Kamireddi, M Eisenstein, E Reddy, P TI Stable expression and rapid purification of Escherichia coli GroEL and GroES chaperonins SO PROTEIN EXPRESSION AND PURIFICATION LA English DT Article ID CARBOXYLASE; HYDROLYSIS AB An Escherichia coli expression vector PRE (P. Reddy, A. Peterkofsky, and K. McKenney, 1989, Nucleic Acids Res. 17, 10473-10488), originally developed for the cloning and expression of lethal genes, was used for cloning and hyperexpression of GroEL and GroES genes. Regulated gene expression is achieved in the PRE vector under the tight control of the lambda P-L promoter. Upon induction of the promoter, stable expression of GroEL to about 60% of the total cell protein was observed. Similarly, stable expression of GroES to about 40% of the total cell protein was achieved. GroES was found to be a heat-stable protein while GroEL was not. Both GroE chaperonins were purified in a single chromatographic step with a yield of about 100 mg GroEL and 25 mg GroES per liter of E. coli culture. GroE chaperonins purified by the protocols described here were active in the renaturation of urea-denatured rhodanese. (C) 1997 Academic Press. C1 NIST, DIV BIOTECHNOL, DNA TECHNOL GRP, GAITHERSBURG, MD 20850 USA. NIST, CTR ADV RES BIOTECHNOL, ROCKVILLE, MD 20850 USA. NR 21 TC 22 Z9 22 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1046-5928 EI 1096-0279 J9 PROTEIN EXPRES PURIF JI Protein Expr. Purif. PD OCT PY 1997 VL 11 IS 1 BP 47 EP 52 DI 10.1006/prep.1997.0764 PG 6 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA XY802 UT WOS:A1997XY80200006 PM 9325138 ER PT J AU Otterman, J Starr, D Brakke, T Davies, R Jacobowitz, H Mehta, A Cheruy, F Prabhakara, C AF Otterman, J Starr, D Brakke, T Davies, R Jacobowitz, H Mehta, A Cheruy, F Prabhakara, C TI Modeling zenith-angle dependence of outgoing longwave radiation: Implication for flux measurements SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID BAND RADIANCE MEASUREMENTS; NIMBUS-7 ERB DATA; BUDGET EXPERIMENT; SEASONAL-VARIATION; CIRRUS CLOUDS; BROAD-BAND; EARTH; SURFACE; ATMOSPHERE; EMISSION AB As shown in previous studies, outgoing-longwave radiation (OLR) can be in error by similar to 7% when evaluated from directional measurements by applying time-averaged angular distribution models (ADMs) to account for the emission anisotropy. In order to develop an insight into the problem of assessing hemispheric emission from directional measurements, we formulate the directional (monochromatic) greenhouse factor g(d), specified as the ratio of a longwave radiance measured above the atmosphere to that emitted from the surface at the same zenith angle theta(r). The explicit expressions for g(d) involve two atmospheric parameters, the optical thickness and the temperature-profile parameter. Oar analysis indicates that under clear conditions a narrow-band radiance, if measured at theta(v) approximate to 57 degrees in atmospheric windows (low values of optical thickness) and at theta(v) approximate to 47 degrees in absorption bands, determines the hemispheric-average radiance to within about 1%. For broad spectral bands, whether under clear or cloudy (solid cover, or ''randomly scattered'' clouds) conditions, the same finding applies at theta(v) approximate to 50 degrees. Thus, the zenith angle of equivalence theta(eq) varies by about +/-5 degrees for different values of the optical thickness; it varies only slightly for different temperature profiles (even though different temperature profiles produce quite different patterns of radiance us. theta(v), that is, different ADMs apply). Measurements at or near theta(eq) therefore constitute direct assessment of OLR, without resorting to ADMs to adjust for the variations of emission with view angle (anisotropy). The existing OLR data should be reexamined accepting measurements only within the range 45-60 degrees of view zenith angles. (C) Elsevier Science Inc., 1997. C1 UNIV ARIZONA,TUCSON,AZ. NOAA,NESDIS,CAMP SPRINGS,MD. ECOLE POLYTECH,CNRS,METEOROL DYNAM LAB,F-91128 PALAISEAU,FRANCE. RP Otterman, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 910-4,GREENBELT,MD 20771, USA. NR 36 TC 9 Z9 9 U1 1 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD OCT PY 1997 VL 62 IS 1 BP 90 EP 100 DI 10.1016/S0034-4257(97)00084-9 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA XV029 UT WOS:A1997XV02900008 ER PT J AU ChenMayer, HH Mildner, DFR Sharov, VA Xiao, QF Cheng, YT Lindstrom, RM Paul, RL AF ChenMayer, HH Mildner, DFR Sharov, VA Xiao, QF Cheng, YT Lindstrom, RM Paul, RL TI A polycapillary bending and focusing lens for neutrons SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A glass polycapillary lens that both bends and focuses a cold neutron beam has been designed and constructed. The bender focuser guides part of the incident beam away from its line of sight and focuses it to a spot of width 0.65 mm at a distance 95 mm from the lens exit and 20 mm below the bottom edge of the beam path, with a gain of 20 in neutron current density. The neutron transmission characteristics of the lens have been determined with two types or position-sensitive detectors, a charge injection device, and an imaging plate. The lens has been tested with prompt gamma measurements on a gadolinium shard and titanium foil. (C) 1997 American Institute of Physics. C1 XRAY OPT SYST INC,ALBANY,NY 12205. NEUTEK,DARNESTOWN,MD 20878. RP ChenMayer, HH (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 14 TC 13 Z9 13 U1 2 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD OCT PY 1997 VL 68 IS 10 BP 3744 EP 3750 DI 10.1063/1.1148020 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YB160 UT WOS:A1997YB16000016 ER PT J AU Rainey, WS AF Rainey, WS TI Fish ladders SO SCIENTIFIC AMERICAN LA English DT Editorial Material RP Rainey, WS (reprint author), NATL MARINE FISHERIES SERV,NW REG,PORTLAND,OR, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD OCT PY 1997 VL 277 IS 4 BP 156 EP 156 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XW437 UT WOS:A1997XW43700046 ER PT J AU Herrmann, B Vance, T AF Herrmann, B Vance, T TI The Internet @ sea SO SEA TECHNOLOGY LA English DT Article C1 PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA. RP Herrmann, B (reprint author), NOAA,OFF CORPS OPERAT,HPCC NETWORKING COMM,SILVER SPRING,MD 20910, USA. RI Wright, Dawn/A-4518-2011 OI Wright, Dawn/0000-0002-2997-7611 NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD OCT PY 1997 VL 38 IS 10 BP 43 EP 45 PG 3 WC Engineering, Ocean SC Engineering GA YC327 UT WOS:A1997YC32700006 ER PT J AU Turcajova, R AF Turcajova, R TI Numerical condition of discrete wavelet transforms SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE biorthogonal wavelets; block circulant matrices; block-Toeplitz operators; numerical condition; translational bases ID COMPACTLY SUPPORTED WAVELETS; BASES; PACKETS AB The recursive algorithm of a (fast) discrete wavelet transform, as well as its generalizations, can be described as repeated applications of block-Toeplitz operators or, in the case of periodized wavelets, multiplications by block circulant matrices. Singular values of a block circulant matrix are the singular values of some matrix trigonometric series evaluated at certain points. The norm of a block-Toeplitz operator is then the essential supremum of the largest singular value curve of this series. For all reasonable wavelets, the condition number of a block-Toeplitz operator thus is the lowest upper bound for the condition of corresponding block circulant matrices of all possible sizes. In the last section, these results are used to study conditioning of biorthogonal wavelets based on B-splines. RP Turcajova, R (reprint author), NATL INST STAND & TECHNOL,BLDG 820,ROOM 365,GAITHERSBURG,MD 20899, USA. NR 14 TC 4 Z9 5 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD OCT PY 1997 VL 18 IS 4 BP 981 EP 999 PG 19 WC Mathematics, Applied SC Mathematics GA XZ715 UT WOS:A1997XZ71500012 ER PT J AU Powell, CJ Shimizu, R AF Powell, CJ Shimizu, R TI Development of standards for surface analysis by ISO Technical Committee 201 on Surface Chemical Analysis SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE ISO/TC 201 on Surface Chemical Analysis; standards; surface analysis AB A summary is given of the organization and work of Technical Committee 201 on Surface Chemical Analysis of the International Organization for Standardization (ISO). Twelve potential international standards are currently in various stages of development and a further thirteen standards are expected to be developed shortly. Information is also given on expected future needs for standards with examples from a recent survey of experts in Auger electron spectroscopy and x-ray photoelectron spectroscopy. (C) 1997 by John Wiley & Sons, Ltd. C1 OSAKA UNIV,FAC ENGN,DEPT APPL PHYS,SUITA,OSAKA 565,JAPAN. RP Powell, CJ (reprint author), NIST,DIV SURFACE & MICROANAL SCI,GAITHERSBURG,MD 20899, USA. NR 9 TC 7 Z9 8 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD OCT PY 1997 VL 25 IS 11 BP 860 EP 868 PG 9 WC Chemistry, Physical SC Chemistry GA YD539 UT WOS:A1997YD53900004 ER PT J AU Landsea, CW AF Landsea, CW TI Will greenhouse gas-induced warming over the nest 50 years lead to higher frequency and greater intensity of hurricanes? Comment SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Letter ID MODEL RP Landsea, CW (reprint author), NOAA,ATLANTIC OCEANOG & METEOROL LAB,HURRICANE RES DIV,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. NR 8 TC 2 Z9 3 U1 1 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD OCT PY 1997 VL 49 IS 5 BP 622 EP 623 DI 10.1034/j.1600-0870.1997.t01-3-00008.x PG 2 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA YG149 UT WOS:A1997YG14900008 ER PT J AU Sun, JX Hu, ZS Hsu, SM AF Sun, JX Hu, ZS Hsu, SM TI The effect of concentration, solvent, and temperature on aggregation of a commercial calcium sulfonate additive as studied by FTIR and light scattering techniques SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 50th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 14-19, 1995 CL CHICAGO, IL SP Soc Tribologists & Lubricat Engineers DE FTIR; solvents; additives; lubricants ID REVERSED MICELLES; WATER; IR; SOLUBILIZATION; SPECTROSCOPY; PRESSURE; MEDIA AB The aggregation of a calcium sulfonate in organic solvents was studied by the Fourier Transform Infrared (FTIR) spectroscopy and dynamic light scattering techniques. The symmetric stretching band of the S=O bond was found to be sensitive to the concentration of the additive and to the polarity of the solvent. A critical micelle concentration (CMC) may exist in the concentration range of 0.04-0.11 millimole/liter. As the solvent polarity increased, the width in half height of the symmetric stretching band of S=O increased, and the interaction between the solvent and the polar head of calcium sulfonate increased accordingly. This interaction weakened the interaction between the polar heads themselves, and thereby the size of the micelle decreased as found by dynamic light scattering. When the polarity of a solvent is strong enough, e.g., in heptanoic acid or water, the micelles formed may revert back to normal micelles. The FTIR spectra and aggregation size of calcium sulfonate in hexadecane showed that higher temperatures decreased the width in half height of the asymmetric stretching bands and concurrently decreased the size of the aggregation. RP Sun, JX (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 26 TC 5 Z9 5 U1 1 U2 1 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD OCT PY 1997 VL 40 IS 4 BP 633 EP 638 DI 10.1080/10402009708983702 PG 6 WC Engineering, Mechanical SC Engineering GA YE971 UT WOS:A1997YE97100012 ER PT J AU Ying, TN Shen, MC Wang, YS Hsu, SM AF Ying, TN Shen, MC Wang, YS Hsu, SM TI Tribology of Si-based ceramics: Wear mechanisms SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 50th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 14-19, 1995 CL CHICAGO, IL SP Soc Tribologists & Lubricat Engineers DE nitrides; carbides; wear; friction; dynamic modelling; wear mechanisms ID SILICON-NITRIDE; CONTACT; TRANSITION; FRICTION; ALUMINA AB The wear mechanisms of Si-based ceramics are examined in terms of speed and load. The results are presented in wear maps which reveal different regimes of wear. This paper examines the effects of normal force and shear force on Si-based ceramic wear in the different wear regimes. In the mild wear regime, the wear processes are dominated by microabrasion and subsurface cracks. The severe wear regime is dominated by microfracture and tensile cracks on the surface. At still higher loads, surface cracks and gross fracture occur. The presence and the effects of third-body particles on the wear mechanisms are also discussed. RP Ying, TN (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 22 TC 9 Z9 9 U1 0 U2 2 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD OCT PY 1997 VL 40 IS 4 BP 685 EP 693 DI 10.1080/10402009708983709 PG 9 WC Engineering, Mechanical SC Engineering GA YE971 UT WOS:A1997YE97100019 ER PT J AU Eadie, BJ AF Eadie, BJ TI Probing particle processes in Lake Michigan using sediment traps SO WATER AIR AND SOIL POLLUTION LA English DT Article; Proceedings Paper CT International Symposium on the Interactions Between Sediments and Water CY SEP 22-26, 1996 CL BAVENO, ITALY ID FIELD ASSESSMENT; CS-137; FLOW AB Sediment trap sampling at an offshore site in southern Lake Michigan has continued for an 18 year period with a sampling Frequency ranging from weekly to semi-annually. During the 6 month unstratified period sediment trap mass and tracer profiles are nearly constant and they have been used to describe the extent of sediment resuspension. After stratification, mass flux rapidly declines and particle tracers are removed from the epilimnion at the rate of 0.5-1 m.d(-1). Exponential profiles of mass flux clearly show the persistence of a benthic nepheloid layer. High frequency sampling with near-bottom sequencing traps show order of magnitude ranges in mass flux over a few day period. RP Eadie, BJ (reprint author), NOAA,GREAT LAKES ENVIRONM RES LAB,2205 COMMONWEALTH BLVD,ANN ARBOR,MI 48105, USA. NR 20 TC 19 Z9 19 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD OCT PY 1997 VL 99 IS 1-4 BP 133 EP 139 DI 10.1023/A:1018336516500 PG 7 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA XW682 UT WOS:A1997XW68200015 ER PT J AU Tatarskii, VI AF Tatarskii, VI TI Formulation of rough-surface scattering theory in terms of phase factors and approximate solutions based on this formulation SO WAVES IN RANDOM MEDIA LA English DT Article ID WAVES AB This paper presents the formulation of rough-surface scattering theory in which the bounded phase shift factors, L(r,alpha) drop exp[i alpha zeta(r)], replace the elevation, zeta(r). Both the Dirichlet and the Neumann problems are considered. The integral equations for secondary surface sources are obtained that contain only this phase function in their kernels. The Neumann (iterative) series for the solutions of the integral equations thus derived are functional Taylor series in powers of L(r,alpha), not in powers of zeta. If we expand L(r,alpha) in these series in powers of zeta(r), we obtain the standard perturbation theory series. Thus, the new formulation corresponds to the partial summation of the perturbation series. Using the Neumann series, we obtain several uniform (with respect to alpha zeta) approximate solutions that contain, as limiting cases, Bragg scattering, the Kirchhoff approximation, and most known advanced approximations. In the case of random surface z = zeta(r), these new expansions contain the function zeta(r) only in the exponents, and, therefore, the result of averaging can be expressed only in terms of the characteristic functions of the multivariate probability distribution of elevations. C1 NOAA,ERL,ETL,BOULDER,CO 80303. RP Tatarskii, VI (reprint author), UNIV COLORADO,CIRES,325 BROADWAY,BOULDER,CO 80303, USA. NR 15 TC 8 Z9 8 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0959-7174 J9 WAVE RANDOM MEDIA JI Waves Random Media PD OCT PY 1997 VL 7 IS 4 BP 557 EP 578 DI 10.1088/0959-7174/7/4/004 PG 22 WC Physics, Multidisciplinary SC Physics GA YC595 UT WOS:A1997YC59500004 ER PT J AU Benz, SP Hamilton, CA Burroughs, CJ Harvey, TE Christian, LA AF Benz, SP Hamilton, CA Burroughs, CJ Harvey, TE Christian, LA TI Stable 1 volt programmable voltage standard SO APPLIED PHYSICS LETTERS LA English DT Article ID JOSEPHSON; JUNCTIONS AB Several fully functional programmable voltage standard chips, each having a total of 32 768 Nb-PdAu-Nb Josephson junctions, have been fabricated and tested. The chips are based on a new design that provides fast programmability (1 mu s) between voltages and stable voltage operation from -1 to +1 V. A comparison of the new standard with a conventional Josephson voltage standard is in agreement to 0.5 +/- 1.1 parts in 10(9). We demonstrate the utility of this standard by measuring the linearity of a digital voltmeter. (C) 1997 American Institute of Physics. C1 IND RES LTD, LOWER HUTT, NEW ZEALAND. RP Benz, SP (reprint author), NATL INST STAND & TECHNOL, 325 BROADWAY, BOULDER, CO 80303 USA. NR 9 TC 122 Z9 122 U1 2 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 29 PY 1997 VL 71 IS 13 BP 1866 EP 1868 DI 10.1063/1.120189 PG 3 WC Physics, Applied SC Physics GA XY993 UT WOS:A1997XY99300041 ER PT J AU Lee, SH Cheong, SW AF Lee, SH Cheong, SW TI Melting of quasi-two-dimensional charge stripes in La5/3Sr1/3NiO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCONDUCTORS; MAGNETISM; PHASES; SPINS; HOLES AB Commensurability effects for nickelates have been studied, for the first time, by neutron scattering on La5/3Sr1/3NiO4. Upon cooling, this system undergoes three successive phase transitions associated with quasi-two-dimensional (2D) commensurate charge and spin stripe ordering in the NiO2 planes. The two lower temperature phases are stripe lattice states with quasi-long-range in-plane charge correlation. When the lattice of 2D charge stripes melts. it goes through an intermediate glass state before becoming a disordered liquid state. This glass state shows short-range charge order without spin order, and may be called a ''stripe glass'' which resembles the hexatic/nematic state in 2D melting. C1 NIST, GAITHERSBURG, MD 20899 USA. AT&T BELL LABS, LUCENT TECHNOL, MURRAY HILL, NJ 07974 USA. RP Lee, SH (reprint author), UNIV MARYLAND, COLLEGE PK, MD 20742 USA. NR 24 TC 129 Z9 129 U1 0 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 29 PY 1997 VL 79 IS 13 BP 2514 EP 2517 DI 10.1103/PhysRevLett.79.2514 PG 4 WC Physics, Multidisciplinary SC Physics GA XZ114 UT WOS:A1997XZ11400032 ER PT J AU Ross, RJ Rosenfeld, S AF Ross, RJ Rosenfeld, S TI Estimating mean weighted temperature of the atmosphere for Global Positioning System applications SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GPS METEOROLOGY; WATER-VAPOR AB A water-vapor-weighted vertically averaged mean temperature of the atmosphere, T-m, is a key parameter in the retrieval of total water content from the measurements of Global Positioning System signal delays. The accuracy of precipitable water estimates is proportional to the accuracy of T-m. The geographic and seasonal variability of T-m based on 23 years of radiosonde soundings at 53 globally distributed stations is presented. Several methods for estimating T-m were evaluated by comparing the estimates against the actual T-m values. Site-specific climatology or site-specific linear regression was superior to the geographically and seasonally invariant regression relationship typically used to estimate T-m. Relative errors at most stations were less than 2%, which corresponds to absolute errors of precipitable water of 0.1-0.5 mm. The station-specific linear regression was superior to climatological means as an estimator except in the tropics, where correlations between T-m and T-sfc were not high, Also, a physical model was developed to indicate the relationship between T-m and other commonly used atmospheric variables. C1 NOAA, NATL ENVIRONM SATELLITE DATA & INFORMAT SERV, OFF CLIMATE RES & APPLICAT, CAMP SPRINGS, MD 20746 USA. RP NOAA, AIR RESOURCES LAB, REAR, 1315 EAST WEST HWY, SILVER SPRING, MD 20910 USA. NR 11 TC 39 Z9 47 U1 0 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 SEP 27 PY 1997 VL 102 IS D18 BP 21719 EP 21730 DI 10.1029/97JD01808 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XY462 UT WOS:A1997XY46200004 ER PT J AU Donner, LJ Seman, CJ Soden, BJ Hemler, RS Warren, JC Strom, J Liou, KN AF Donner, LJ Seman, CJ Soden, BJ Hemler, RS Warren, JC Strom, J Liou, KN TI Large-scale ice clouds in the GFDL SKYHI general circulation model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SEASONAL-VARIATION; CARBON-DIOXIDE; WATER-CONTENT; ECMWF MODEL; CLIMATE; PARAMETERIZATION; FEEDBACK; TEMPERATURE; RADIATION; MICROPHYSICS AB Ice clouds associated with large-scale atmospheric processes are studied using the SKYHI general circulation model (GCM) and parameterizations for their microphysical and radiative properties. The ice source is deposition from vapor, and the ice sinks are gravitational settling and sublimation. Effective particle sizes for ice distributions are related empirically to temperature. Radiative properties are evaluated as functions of ice path and effective size using approximations to detailed radiative-transfer solutions (Mie theory and geometric ray tracing). The distributions of atmospheric ice and their impact on climate and climate sensitivity are evaluated by integrating the SKYHI GCM (developed at the Geophysical Fluid Dynamics Laboratory) for six model months. Most of the major climatological cirrus regions revealed by satellite observations appear in the GCM. The radiative forcing associated with ice clouds acts to warm the Earth-atmosphere system. Relative to a SKYHI integration without these clouds, zonally averaged temperatures are warmer in the upper tropical troposphere with ice clouds. The presence of ice produced small net changes in the sensitivity of SKYHI climate to radiative perturbations, but this represents an intricate balance among changes in clear-, cloud-, solar-, and longwave-sensitivity components. Deficiencies in the representation of ice clouds are identified as results of biases in the large-scale GCM fields which drive the parameterization and neglect of subgrid variations in these fields, as well as parameterization simplifications of complex microphysical and radiative processes. C1 UNIV STOCKHOLM, INT METEOROL INST, STOCKHOLM, SWEDEN. UNIV UTAH, DEPT METEOROL, SALT LAKE CITY, UT 84112 USA. RP PRINCETON UNIV, NOAA, GEOPHYS FLUID DYNAM LAB, POB 308, PRINCETON, NJ 08542 USA. NR 31 TC 40 Z9 40 U1 1 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 SEP 27 PY 1997 VL 102 IS D18 BP 21745 EP 21768 DI 10.1029/97JD01488 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XY462 UT WOS:A1997XY46200006 ER PT J AU Bates, JJ Jackson, DL AF Bates, JJ Jackson, DL TI A comparison of water vapor observations with AMIP I simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MODEL INTERCOMPARISON PROJECT; UPPER-TROPOSPHERIC HUMIDITY; BRIGHTNESS TEMPERATURES; SATELLITE; VARIABILITY; CIRCULATION; CLIMATOLOGY; RAINFALL AB Water vapor simulations from the Atmospheric Model Intercomparison Project have been compared with satellite observations of precipitable water and upper tropospheric humidity. The model means and standard deviations of precipitable water compare favorably with observations and most models also reproduce the observed seasonal cycle well. The models show a regional dependence in reproducing the observed interannual variability of precipitable water, doing better in the deep tropics than in the subtropics and midlatitudes. The skill in reproducing the observed interannual variability in the deep tropics is attributed to accurate reproduction of anomalies during the 1982-1983 El Nino-Southern Oscillation event. Comparisons between modeled and observed upper tropospheric humidity are more problematic, but significant differences are found in both the mean values and the ability of the models to produce the observed seasonal and interannual variability. Additional comparisons of both models and observations are required to resolve these discrepancies. Examination of leading modes of interannual variability shows that models that do a better job in simulating the observed all-sky outgoing longwave radiation in the tropics also do a better job of simulating the observed upper tropospheric humidity. C1 UNIV COLORADO, CIRES, BOULDER, CO 80309 USA. RP NOAA, ENVIRONM RES LAB, RECD, CLIMATE DIAGNOST CTR, 325 BROADWAY, BOULDER, CO 80303 USA. RI Bates, John/D-1012-2009; Jackson, Darren/D-5506-2015 OI Bates, John/0000-0002-8124-0406; Jackson, Darren/0000-0001-5211-7866 NR 29 TC 18 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD SEP 27 PY 1997 VL 102 IS D18 BP 21837 EP 21852 DI 10.1029/97JD01769 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XY462 UT WOS:A1997XY46200012 ER PT J AU vandenDool, HM Saha, S Schemm, J Huang, J AF vandenDool, HM Saha, S Schemm, J Huang, J TI A temporal interpolation method to obtain hourly atmospheric surface pressure tides in Reanalysis 1979-1995 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; MASS AB The diurnal cycle in climatology as revealed in National Centers for Environmental Prediction's Reanalysis 1979-1995 has been studied for global gridded data at 0000, 0600, 1200 and 1800 UT. Climatologies have been prepared for each of the four time levels separately. There are substantial differences in, for instance, the 0000(2) and 0600 UT climatologies, owing to a diurnal cycle and/or what is referred to commonly as atmospheric tides. The semidiurnal tide is quite strong in the mass fields, but with sampling every 6 hours at the Nyquist frequency, some aspects cannot be studied properly. However, a method of interpolation based on spatial harmonic waves moving at an empirically determined speed can be called upon to make an educated guess about the atmospheric tides at any times in between. This interpolation technique is similar to the one published by Van den Dool and Qin [1996], but the wave speeds are not like the slow Rossby modes but roughly 15 degrees westward per hour. We present the global tides in surface pressure thus obtained for every hour of the day for January. C1 NOAA, NATL WEATHER SERV,NCEP,WNP23,WWB, ENVIRONM MODELING CTR, WASHINGTON, DC 20233 USA. RP NOAA, NATL WEATHER SERV,NCEP,WNP51,WWB, CLIMATE PREDICT CTR, 4700 SILVER HILL RD, WASHINGTON, DC 20233 USA. NR 17 TC 25 Z9 25 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 SEP 27 PY 1997 VL 102 IS D18 BP 22013 EP 22024 DI 10.1029/97JD01571 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XY462 UT WOS:A1997XY46200025 ER PT J AU Klein, R OHare, PAG Jacob, I AF Klein, R OHare, PAG Jacob, I TI Standard molar enthalpies of formation of alloys in the pseudobinary system Zr(AlxCo1-x)(2) at the temperature 298.15 K SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE thermodynamics; enthalpy of formation; (zirconium plus aluminum plus cobalt) alloys; calorimetry ID ZR(ALXFE1-X)2 SYSTEM; HYDROGEN ABSORPTION; MOSSBAUER; STRENGTH AB The standard molar enthalpies of formation Delta(f)H(m) degrees of alloys with compositions in the pseudobinary system Zr(AlxCo1-x)(2)Zr have been determined by solution calorimetry in a mixture of hydrofluoric and nitric acids. The values of Delta(f)H(m) degrees(298.15 K) obtained are as follows: -(113+/-11) kJ mol(-1) for x=0; -(123+/-8) kJ mol(-1) for x=1/12; -(120+/-8) kJ mol(-1) for x=1/6; -(130+/-7) for x=1/4; and -(147+/-10) kJ mol(-1) for x=1/2. Uncertainties correspond to twice the standard deviation of the mean, The following empirical relation was found to be applicable over the range of compositions studied: Delta(f)H(m) degrees{Zr(AlxCo1-x)(2)}approximate to x.Delta(f)H(m) degrees(ZrAl2)+(1-x).Delta(f)H(m) degrees(ZrCo2). (C) 1997 Elsevier Science S.A. C1 BEN GURION UNIV NEGEV,DEPT NUCL ENGN,IL-84105 BEER SHEVA,ISRAEL. RP Klein, R (reprint author), NIST,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899, USA. NR 12 TC 10 Z9 10 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 SEP 26 PY 1997 VL 261 IS 1-2 BP 204 EP 208 DI 10.1016/S0925-8388(97)00226-0 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA YE036 UT WOS:A1997YE03600029 ER PT J AU Smith, WHF Sandwell, DT AF Smith, WHF Sandwell, DT TI Global sea floor topography from satellite altimetry and ship depth soundings SO SCIENCE LA English DT Article ID BATHYMETRIC PREDICTION; OCEANIC LITHOSPHERE; SOUTH-PACIFIC; HEAT-FLOW; AGE; CONSEQUENCES; GRAVITY; RESOLUTION; ANOMALIES; SEAMOUNTS AB A digital bathymetric map of the oceans with a horizontal resolution of 1 to 12 kilometers was derived by combining available depth soundings with high-resolution marine gravity information from the Geosat and ERS-1 spacecraft. Previous global bathymetric maps lacked features such as the 1600-kilometer-long Foundation Seamounts chain in the South Pacific. This map shows relations among the distributions of depth, sea floor area, and sea floor age that do not fit the predictions of deterministic models of subsidence due to lithosphere cooling but may be explained by a stochastic model in which randomly distributed reheating events warm the lithosphere and raise the ocean floor. C1 UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, LA JOLLA, CA 92093 USA. RP NOAA, CODE E-CC-2, 1315 EAST-WEST HIGHWAY, SILVER SPRING, MD 20910 USA. RI Smith, Walter/F-5627-2010; OI Smith, Walter/0000-0002-8814-015X; Sandwell, David/0000-0001-5657-8707 NR 50 TC 1898 Z9 1946 U1 12 U2 118 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 SEP 26 PY 1997 VL 277 IS 5334 BP 1956 EP 1962 DI 10.1126/science.277.5334.1956 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XX849 UT WOS:A1997XX84900033 ER PT J AU Herne, TM Tarlov, MJ AF Herne, TM Tarlov, MJ TI Characterization of DNA probes immobilized on gold surfaces SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID NUCLEIC-ACIDS; HYBRIDIZATION; ARRAYS; OLIGONUCLEOTIDES; SPECTROSCOPY; SUPPORTS; AU(111) AB We have characterized thiol-derivatized, single-stranded DNA (5'-HS-(CH2)(6)-CAC GAC GTT GTA AAA CGA CGG CCA G-3', abbreviated HS-ssDNA) attached to gold via a sulfur-gold linkage using X-ray photoelectron spectroscopy (XPS), ellipsometry, and P-32-radiolabeling experiments. We found that hybridization of surface-bound HS-ssDNA is dependent on surface coverage. The buffer concentration of the HS-ssDNA solution was found to have a profound effect on surface coverage, with adsorption greatly reduced at low salt concentration. More precise control over surface coverage was achieved by creating mixed monolayers of the thiol-derivatized probe and a spacer thiol, mercaptohexanol (MCH), by way of a two-step method, where first the gold substrate is exposed to a micromolar solution of HS-ssDNA, followed by exposure to a millimolar solution of MCH. A primary advantage of using this two-step process to form HS-ssDNA/MCH mixed monolayers is that nonspecifically adsorbed DNA is largely removed from the surface. Thus, the majority of surface-bound probes are accessible for specific hybridization with complementary oligonucleotides and are able to discriminate between complementary and noncomplementary target molecules. Moreover, the probe-modified surfaces were found to be stable, and hybridization reactions were found to be completely reversible and specific in a series of experiments where duplex melting was examined. RP Herne, TM (reprint author), NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 18 TC 1042 Z9 1063 U1 22 U2 220 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 SEP 24 PY 1997 VL 119 IS 38 BP 8916 EP 8920 DI 10.1021/ja9719586 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA XX820 UT WOS:A1997XX82000019 ER PT J AU Bartsch, T Muller, A Spies, W Linkemann, J Danared, H DeWitt, DR Gao, H Zong, W Schuch, R Wolf, A Dunn, GH Pindzola, MS Griffin, DC AF Bartsch, T Muller, A Spies, W Linkemann, J Danared, H DeWitt, DR Gao, H Zong, W Schuch, R Wolf, A Dunn, GH Pindzola, MS Griffin, DC TI Field enhanced dielectronic recombination of Si11+ ions SO PHYSICAL REVIEW LETTERS LA English DT Article ID DISTORTED-WAVE CALCULATIONS; ELECTRIC-FIELDS; EXTERNAL-FIELD; STORAGE-RING; C3+ AB The enhancement of dielectronic recombination by applied electric fields has been observed and measured for the first time in a wide range of controlled and measurable fields using multiply charged ions. The heavy ion storage ring CRYRING at Stockholm University was used to store a beam of Si11+ and collide it with a cold electron target. Rydberg resonances up to n = 25 are resolved for both the 2(p3/2) and 2(p1/2) series. The observation of a substantial monotonic increase of the rate coefficient for the group of higher Rydberg states is in puzzling disagreement with theoretical calculations of electric field enhanced dielectronic recombination. C1 UNIV STOCKHOLM,DEPT PHYS,S-10405 STOCKHOLM,SWEDEN. MAX PLANCK INST KERNPHYS,D-69117 HEIDELBERG,GERMANY. UNIV HEIDELBERG,INST PHYS,D-69120 HEIDELBERG,GERMANY. UNIV COLORADO,JILA,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. AUBURN UNIV,DEPT PHYS,AUBURN,AL 36849. ROLLINS COLL,DEPT PHYS,WINTER PK,FL 32749. RP Bartsch, T (reprint author), UNIV GIESSEN,INST KERNPHYS,D-35392 GIESSEN,GERMANY. RI Muller, Alfred/A-3548-2009 OI Muller, Alfred/0000-0002-0030-6929 NR 22 TC 59 Z9 59 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 22 PY 1997 VL 79 IS 12 BP 2233 EP 2236 DI 10.1103/PhysRevLett.79.2233 PG 4 WC Physics, Multidisciplinary SC Physics GA XW939 UT WOS:A1997XW93900018 ER PT J AU Weinreb, M Jamieson, M Fulton, N Chen, Y Johnson, JX Bremer, J Smith, C Baucom, J AF Weinreb, M Jamieson, M Fulton, N Chen, Y Johnson, JX Bremer, J Smith, C Baucom, J TI Operational calibration of geostationary operational environmental satellite-8 and -9 imagers and sounders SO APPLIED OPTICS LA English DT Article DE calibration; infrared radiation; visible radiation; meteorological satellite radiometers AB We describe the operational in-orbit calibration of the Geostationary Operational Environmental Satellite (GOES)-8 and -9 imagers and sounders. Ii? the infrared channels the calibration is based on observations of space and an onboard blackbody. The calibration equation expresses radiance as a quadratic in instrument output. To suppress noise in the blackbody sequences, we filter the calibration slopes. The calibration equation also accounts for an unwanted variation of the reflectances of the instruments' scan mirrors with east-west scan position, which was not discovered until the instruments were in orbit. The visible channels are not calibrated, but the observations are provided relative to the level of space and are normalized to minimize east-west striping in the images. Users receive scaled radiances in a GOES variable format (GVAR) data stream. We describe the procedure users can apply to transform GVAR counts into radiances, temperatures, and mode-ii counts. (C) 1997 Optical Society of America. C1 INTEGRAL SYST INC,LANHAM,MD 20706. SWALES & ASSOCIATES INC,BELTSVILLE,MD 20705. RP Weinreb, M (reprint author), NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,WASHINGTON,DC 20233, USA. NR 21 TC 90 Z9 90 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 SEP 20 PY 1997 VL 36 IS 27 BP 6895 EP 6904 DI 10.1364/AO.36.006895 PG 10 WC Optics SC Optics GA XV502 UT WOS:A1997XV50200028 PM 18259561 ER PT J AU Gilpin, T Apel, E Fried, A Wert, B Calvert, J Zhang, GF Dasgupta, PK Harder, JW Heikes, B Hopkins, B Westberg, H Kleindienst, T Lee, YN Zhou, XL Lonneman, W Sewell, S AF Gilpin, T Apel, E Fried, A Wert, B Calvert, J Zhang, GF Dasgupta, PK Harder, JW Heikes, B Hopkins, B Westberg, H Kleindienst, T Lee, YN Zhou, XL Lonneman, W Sewell, S TI Intercomparison of six ambient [CH2O] measurement techniques SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CARBONYL-COMPOUNDS; OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; LASER ABSORPTION-SPECTROSCOPY; LIQUID-CHROMATOGRAPHY; FORMALDEHYDE; AIR; ISOPRENE; HCHO; PHOTOOXIDATION; INTERFERENCE AB From May 29 to June 3, 1995 a blind intercomparison of six ambient formaldehyde measurement techniques took place at a field site near the National Center for Atmospheric Research in Boulder, Colorado. The continuous measurement methods intercompared were tunable diode laser absorption spectroscopy, (TDLAS); coil/2,4-dinitrophenylhydrazine, (CDNPH); 1,3-cyclohexanedione-diffusion scrubber (CHDDS); and the coil enzyme method (CENZ). In addition, two different cartridge methods were compared: silica gel-2,4-dinitrophenylhydrazine (DPNH) systems and a C-18-DNPH system. The intercomparison was conducted with spiked zero air (part 1) and ambient air (part 2). The CH2O standards for part 1 were calibrated by several independent methods and delivered to participants via a common glass manifold with potential trace gas interferants common to ambient air (O-3, SO2, NO2, isoprene, H2O). The TDLAS system was used to confirm the absolute accuracy of the standards and served as a mission reference for part 1. The ambient phase lasted 44 hours with all participants sampling from a common glass tower. Differences between the ambient [CH2O] observed by the TDLAS and the other continuous methods were significant in some cases. For matched ambient measurement times the average ratios (+/- 1 sigma) [CH2O](measured)/[CH2O](TDLAS) were: 0.89 +/- 0.12 (CDNPH); 1.30 +/- 0.02 (CHDDS); 0.63 +/- 0.03 (CENZ), The methods showed similar variations but different absolute values and the divergences appeared to result largely from calibration differences (no gas phase standards were used by groups other than NCAR). When the regressions of the participant [CH2O] values versus the TDLAS values, (measured in part 1), were used to normalize all of the results to the common gas phase standards of the NCAR group, the average ratios (+/- 1 sigma), [CH2O](corrected)/[CH2O](TDLAS) for the first measurement period were much closer to unity: 1.04 +/- 0.14 (CDNPH), 1.00 +/- 0.11 (CHDDS), and 0.82 +/- 0.08 (CENZ). With the continuous methods used here, no unequivocal interferences were seen when SO2, NO2, O-3, and isoprene impurities were added to prepared mixtures or when these were present in ambient air. The measurements with the C-18 DNPH (no O-3 scrubber) and silica gel DNPH cartridges (with O-3 scrubber) showed a reasonable correlation with the TDLAS measurements, although the results from the silica cartridges were about a factor of two below the standards in the spike experiments and about 35% below in the ambient measurements. Using the NCAR gas-phase spike data to calibrate the response of the silica gel cartridges in the ambient studies, the results are the same within statistical uncertainty. When the same gas phase calibration was used with the C-18 cartridges, the results showed a positive bias of about 35%, presumably reflecting a positive ozone interference in this case (no ozone scrubber used). The silica DNPH cartridge results from the second participant were highly scattered and showed no significant correlation with the TDLAS measurements. C1 TEXAS TECH UNIV, DEPT CHEM & BIOCHEM, LUBBOCK, TX 79409 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. UNIV RHODE ISL, GRAD SCH OCEANOG, CTR ATMOSPHER STUDIES, NARRAGANSETT, RI 02882 USA. WASHINGTON STATE UNIV, CHEM ENGN LAB ATMOSPHER RES, PULLMAN, WA 99164 USA. MANTECH ENVIRONM TECHNOL INC, ATMOSPHER CHEM GRP, RES TRIANGLE PK, NC 27709 USA. BROOKHAVEN NATL LAB, ENVIRONM CHEM DIV, UPTON, NY 11973 USA. US EPA, NERL, RES TRIANGLE PK, NC 27711 USA. PHILLIPS ACAD, ANDOVER, MA USA. RP Gilpin, T (reprint author), NATL CTR ATMOSPHER RES, POB 3000, BOULDER, CO 80307 USA. NR 50 TC 67 Z9 68 U1 2 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 SEP 20 PY 1997 VL 102 IS D17 BP 21161 EP 21188 DI 10.1029/97JD01314 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX380 UT WOS:A1997XX38000001 ER PT J AU Klonecki, A Levy, H AF Klonecki, A Levy, H TI Tropospheric chemical ozone tendencies in CO-CH4-NOy-H2O system: Their sensitivity to variations in environmental parameters and their application to a global chemistry transport model study SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; BUDGET; DISTRIBUTIONS; MECHANISM; BALANCE; IMPACT; ORIGIN; SITE; OH AB A photochemical box model with CO-CH4-NOy-H2O chemistry is used to calculate the diurnally averaged net photochemical rate of change of ozone (hereinafter called the chemical ozone tendency) in the troposphere for different values of parameters: NOx and ozone concentration, temperature, humidity, CO concentration, and surface albedo. To understand the dependency of the chemical ozone tendency on the input parameters, a detailed sensitivity study is performed, Subsequently, the expected variations of the ozone tendencies with altitude, latitude, and season are analyzed. The magnitude of the tendency decreases rapidly with height mostly as a result of lower absolute humidity and temperature. In the upper troposphere (at 190 mbar) the maximum tendencies are below 2 parts per billion by volume/day. Lower temperature and specific humidity cause a shift of the value of NOx at which the ozone production balances the destruction of ozone (balance point) to lower NOx values; these two parameters are also, to a large extent, responsible for lower magnitudes of the tendency at higher latitudes and in winter. In the upper troposphere we find that the net tendency is at least as sensitive to variations in H2O concentration as to NOx. This suggests a possible synergism between direct NOx pollution by aircraft and the indirect modification of H2O by climate change. In the second part of the paper the box model calculated rates are used as ozone's chemical tendency terms during a simulation conducted with the three-dimensional global chemistry transport model (GCTM). The box model is used to calculate the tendencies as a function of NOx and ozone at all tropospheric levels of the GCTM, at nine latitudes and for four seasons using zonally and monthly averaged data: water vapor and temperature from observations and model CO. These tables together with the NOx fields obtained in an earlier GCTM simulation are used in the GCTM simulation of O-3 if nonmethane hydrocarbon levels are low. The global monthly averaged chemical ozone tendency fields saved during the simulation are presented and analyzed for the present-day and preindustrial conditions. The chemical tendency fields show a strong correlation with the NOx fields. In contrast with the lower and middle troposphere where the tendencies are negative in remote regions over the oceans, in the upper troposphere, where NOx is generally greater than 50 parts per trillion by volume and the balance point is low, the tendencies are generally small but positive, The GCTM simulations of the preindustrial ozone show that in the upper troposphere the present-day ozone tendencies are greater than the simulated preindustrial tendencies. In the boundary layer and in the midtroposphere the present-day tendencies are greater near anthropogenic NOx sources and smaller (generally more negative), due to higher ozone levels, in regions not affected by these sources. C1 NOAA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08542 USA. RP Klonecki, A (reprint author), PRINCETON UNIV, ATMOSPHER & OCEAN SCI PROGRAM, PRINCETON, NJ 08540 USA. NR 53 TC 42 Z9 42 U1 1 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 SEP 20 PY 1997 VL 102 IS D17 BP 21221 EP 21237 DI 10.1029/97JD01805 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX380 UT WOS:A1997XX38000005 ER PT J AU Solomon, S Borrmann, S Garcia, RR Portmann, R Thomason, L Poole, LR Winker, D McCormick, MP AF Solomon, S Borrmann, S Garcia, RR Portmann, R Thomason, L Poole, LR Winker, D McCormick, MP TI Heterogeneous chlorine chemistry in the tropopause region SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IN-SITU MEASUREMENTS; LOWER STRATOSPHERE; VOLCANIC AEROSOLS; CIRRUS CLOUDS; SAGE-II; VERTICAL-DISTRIBUTION; CLIMATIC IMPLICATIONS; MIDDLE ATMOSPHERE; HYDROGEN-CHLORIDE; NUMERICAL-MODEL AB Satellite observations of cloud optical depths and occurrence frequencies are used as input to a two-dimensional numerical model of the chemistry and dynamics of the atmosphere to study the effects of heterogeneous reactions on cloud surfaces upon chemical composition and ozone depletion in the tropopause region, Efficient reactions of ClONO2 with HCl and H2O, and of HOCl with HCl, are likely to take place on the surfaces of cirrus clouds [Borrmann et al., 1996] and perturb chlorine chemistry, much as they do on polar stratospheric clouds present at higher altitudes and colder temperatures, Because of the very low predicted background abundances of ClO near the tropopause, such reactions could enhance the local ClO mixing ratios by up to 30-fold at midlatitudes. Substantial perturbations are also predicted for related chemical species (e.g., HCl, HOCl, ClONO2, NO2, HO2) in the midlatitude and tropical tropopause regions due to these heterogeneous reactions. If cirrus clouds occur with sufficient frequency and spatial extent, they could influence not only the chemical composition but also the ozone depletion in the region near the tropopause. Because of variations in observed cloud occurrence frequency and in photochemical and dynamical timescales, the presence of cirrus clouds likely has its largest effect on ozone near the midlatitude tropopause of the northern hemisphere in summer. C1 NASA, LANGLEY RES CTR, AEROSOL RES BRACH, HAMPTON, VA 23665 USA. HAMPTON UNIV, DEPT PHYS, HAMPTON, VA 23665 USA. NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. UNIV MAINZ, INST PHYS ATMOSPHARE, D-6500 MAINZ, GERMANY. RP Solomon, S (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E-AL8, BOULDER, CO 80303 USA. RI Portmann, Robert/C-4903-2009; Borrmann, Stephan/E-3868-2010; OI Portmann, Robert/0000-0002-0279-6087; Thomason, Larry/0000-0002-1902-0840 NR 78 TC 141 Z9 142 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 SEP 20 PY 1997 VL 102 IS D17 BP 21411 EP 21429 DI 10.1029/97JD01525 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX380 UT WOS:A1997XX38000017 ER PT J AU Andronache, C Chameides, WL AF Andronache, C Chameides, WL TI Interactions between sulfur and soot emissions from aircraft and their role in contrail formation .1. Nucleation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID JET AIRCRAFT; AEROSOLS; PARTICLES; PLUME; STRATOSPHERE; CONDENSATION; HYDRATION; WAKE AB A numerical model of the time evolution of subsonic aircraft exhaust is used to evaluate the possible activation of soot particles by collisions with SO2 and H2SO4 gas molecules and Brownian coagulation with H2SO4/H2O aerosol formed by homogeneous nucleation. The soluble mass fraction accumulated on soot by the three processes is estimated for emission indices of sulfur from 0.001 to 3 g kg(-1). The calculations indicate that the soluble mass fraction of sulfate added to soot particles (assumed to be totally hydrophobic at the point of exhaust) can be large enough to form activated particles within the exhaust plumes of aircraft operating on fuels with typical sulfur contents. However, for emissions from aircraft operating on extremely low sulfur fuels, the soluble material added to soot particles is not sufficient to activate them within the time frame observed for contrail formation. This result, coupled with the Busen and Schumann [1995] observations of contrail formation from an aircraft using 0.004 g S kg(-1) fuel, suggests that heterogeneous interactions between soot and sulfur within the exhaust plume are not sufficient to explain the presence of activated particles and contrails in the wakes of high altitude aircraft if the emitted sulfur is in the form of SO2 only. It is probable that soot particles already have enough soluble material when emitted from the engine exhaust, or/and a higher conversion of sulfur into H2SO4 enable them to act as cloud condensation nuclei (CCN) for contrails. C1 GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. RP Andronache, C (reprint author), PRINCETON UNIV, NOAA,GFDL,FORRESTAL CAMPUS,US ROUTE 1, POB 308, PRINCETON, NJ 08542 USA. RI Andronache, Constantin/C-4431-2011 OI Andronache, Constantin/0000-0001-5375-7056 NR 37 TC 12 Z9 12 U1 1 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 SEP 20 PY 1997 VL 102 IS D17 BP 21443 EP 21451 DI 10.1029/97JD01374 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX380 UT WOS:A1997XX38000019 ER PT J AU Waugh, DW Hall, TM Randel, WJ Rasch, PJ Boville, BA Boering, KA Wofsy, SC Daube, BC Elkins, JW Fahey, DW Dutton, GS Volk, CM Vohralik, PF AF Waugh, DW Hall, TM Randel, WJ Rasch, PJ Boville, BA Boering, KA Wofsy, SC Daube, BC Elkins, JW Fahey, DW Dutton, GS Volk, CM Vohralik, PF TI Three-dimensional simulations of long-lived tracers using winds from MACCM2 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; SHAPE-PRESERVING INTERPOLATION; STRATOSPHERIC CARBON-DIOXIDE; SEMI-LAGRANGIAN TRANSPORT; MIDDLE ATMOSPHERE; ANNUAL CYCLE; 3-DIMENSIONAL SIMULATIONS; SULFUR-HEXAFLUORIDE; UPPER TROPOSPHERE; AIR AB Three-dimensional simulations of the stratospheric constituents CH4, N2O, O-3, SF6, and CO2 over an annual cycle have been performed using a semi-Lagrangian chemical transport model [Rasch and Williamson, 1990; Rasch et al., 1994] driven by archived wind data from the Middle Atmosphere version of the National Center for Atmospheric Research Community Climate Model version 2 (MACCM2) general circulation model. The constituents undergo chemical production and loss at rates calculated by two-dimensional photochemical models. We compare these ''off-line'' simulations of CH4 and N2O with ''on-line'' simulations in which the trace constituent distributions are computed interactively within the MACCM2 general circulation model and find good agreement even when daily averaged wind data and no subgrid scale parameterized mixing are used in the off-line simulations. We also compare the model simulations to satellite, aircraft, and balloon measurements. In most regions and seasons, the zonally averaged model CH4, N2O, and O-3 fields agree cc ell with observations. Notable discrepancies are (1) a lack of a ''double peak'' structure in the zonally averaged mixing ratios of model CH4 and N2O at equinox, (2) an overall underestimate of CH4 and N2O in the upper stratosphere, and (3) an underestimate of the height of the mixing ratio peak in O-3, particularly at high latitudes. We find good agreement between modeled CO2 and SF6 and recent aircraft observations in the lower stratosphere, and balloon measurements in the lower and middle stratosphere. From the SF6 distribution we determine the mean age of air in the model stratosphere, with values as old as 10 years in the wintertime polar upper stratosphere. In addition, we simulate the annual cycle of CO2, a stringent test of model transport, which supplements the mean age. We obtain good agreement with aircraft, measurements in phase and magnitude at the tropical tropopause, and the vertical profiles of CO2 are similar to those observed. However, the amplitude of the cycle attenuates too rapidly with height in the model stratosphere, suggesting the influence of midlatitude air and/or the vertical diffusion are too large in the model tropics. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. HARVARD UNIV, DIV APPL SCI, CAMBRIDGE, MA 02138 USA. HARVARD UNIV, DEPT EARTH & PLANETARY SCI, CAMBRIDGE, MA 02138 USA. NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. UNIV COLORADO, NOAA, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. CSIRO, DIV TELECOMMUN & IND PHYS, LINDFIELD, NSW, AUSTRALIA. RP Waugh, DW (reprint author), MONASH UNIV, COOPERAT RES CTR SO HEMISPHERE METEOROL, WELLINGTON RD, CLAYTON, VIC 3168, AUSTRALIA. RI Fahey, David/G-4499-2013; Randel, William/K-3267-2016; Waugh, Darryn/K-3688-2016 OI Fahey, David/0000-0003-1720-0634; Randel, William/0000-0002-5999-7162; Waugh, Darryn/0000-0001-7692-2798 NR 50 TC 55 Z9 55 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 SEP 20 PY 1997 VL 102 IS D17 BP 21493 EP 21513 DI 10.1029/97JD00793 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX380 UT WOS:A1997XX38000023 ER PT J AU Samuelson, S Tobias, DJ Martyna, GJ AF Samuelson, S Tobias, DJ Martyna, GJ TI Modern computational methodology applied to the simulation of blocked trialanine peptide in vacuo, water clusters, and bulk water SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MOLECULAR-DYNAMICS SIMULATIONS; HELIX FORMATION; ALPHA-HELIX; ALGORITHMS; PROTEIN; ENERGY; EQUILIBRIUM; TEMPERATURE; ALANINE; TURNS AB The results of computer simulation studies of CH3CO-(Ala)(3)-NHCH3 solvated in bulk computer water, solvated in computer water clusters, and in vacuo (isolated model molecule) at T = 300 K using modern computational methods are reported. The simulations were performed using a new multipurpose molecular dynamics package, PINY_MD, which utilizes recently developed simulation techniques and is capable of evolving the peptide-water system with an integration time step of 6 fs, 6 times the usual value. Specifically, the conformational free energy surface of the peptide is calculated via umbrella sampling using the distance between the carbonyl oxygen of the N-terminal blocking group and the amide hydrogen of the C-terminal blocking group as the reaction coordinate. Comparisons are made between results obtained using the several different force fields, CHARMM22 (MacKerell, A. D., Jr.; et al., unpublished), CHARMM19 (Brooks, B., et al. J. Comput. Chem 1983, 4, 187.) and AMBER95 (Cornell et al. J. Am. Chem. Sec. 1995, 117, 5179.). Contact is made with the early studies on this system under the conditions of constant temperature and volume using the CHARMM19 force field to model the interactions, a small system and spherical cutoff to treat the Coulombic interactions (Tobias, D. J.; Brooks, C. L., III Biochemistry 1991, 30, 6059-6070.). Quantitative results are presented on effects of finite size, the truncation of Coulombic interactions in periodic systems, and external pressure. Physically, the studies demonstrate quantitatively the effects of progressive hydration (moving the peptide from vacuum to clusters and into the bulk) on internal peptide hydrogen bonding. C1 INDIANA UNIV,DEPT CHEM,BLOOMINGTON,IN 47405. NATL INST STAND & TECHNOL,CTR NEUTRON RES,GAITHERSBURG,MD 20899. RI Tobias, Douglas/B-6799-2015 NR 49 TC 25 Z9 26 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 SEP 18 PY 1997 VL 101 IS 38 BP 7592 EP 7603 DI 10.1021/jp9704269 PG 12 WC Chemistry, Physical SC Chemistry GA XX154 UT WOS:A1997XX15400035 ER PT J AU Tsai, V Wang, XS Williams, ED Schneir, J Dixson, R AF Tsai, V Wang, XS Williams, ED Schneir, J Dixson, R TI Conformal oxides on Si surfaces SO APPLIED PHYSICS LETTERS LA English DT Article ID ENERGY ELECTRON-DIFFRACTION; SCANNING-TUNNELING-MICROSCOPY; VICINAL SI(111) SURFACES; ATOMIC-FORCE MICROSCOPY; SI/SIO2 INTERFACE; SILICON SURFACES; PHASE-SEPARATION; STEP; ROUGHNESS; SI(001) AB The characteristics of the Si-vacuum interface were compared with the characteristics of the oxide-air interface formed following room temperature oxidation for a variety of samples. Scanning tunneling microscopy was used to measure the surface structure following vacuum preparation, and atomic force microscopy was used to measure the oxide surface on the same samples following exposure to air. Samples investigated included nominally flat Si(111) with equilibrated and quenched surface configurations, Si(111) miscut by 1.25 degrees toward the [(2) over bar 11] and equilibrated to yield the faceted structure, and nominally flat Si(001) wafers. In all cases, the step morphology of the clean surfaces was duplicated on the surface of the oxide. (C) 1997 American Institute of Physics. C1 NIST,GAITHERSBURG,MD 20899. RP Tsai, V (reprint author), UNIV MARYLAND,DEPT MAT ENGN,COLLEGE PK,MD 20742, USA. RI Wang, Xue-sen/G-2749-2012 OI Wang, Xue-sen/0000-0002-5510-3002 NR 30 TC 36 Z9 36 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 SEP 15 PY 1997 VL 71 IS 11 BP 1495 EP 1497 DI 10.1063/1.119947 PG 3 WC Physics, Applied SC Physics GA XV726 UT WOS:A1997XV72600020 ER PT J AU Lee, BP Fisher, ME AF Lee, BP Fisher, ME TI Charge oscillations in Debye-Huckel theory SO EUROPHYSICS LETTERS LA English DT Article ID IONIC FLUIDS; COULOMBIC CRITICALITY; GINZBURG CRITERION AB The recent generalized Debye-Huckel (GDH) theory is applied to the calculation of the charge-charge correlation function, G(zz)(r). The resulting expression satisfies both i) the charge neutrality condition and ii) the Stillinger-Lovett second-moment condition for all T and pry, the overall ion density, and iii) exhibits charge oscillations for densities above a ''Kirkwood line'' in the (rho(N),T)-plane. This corrects the normally assumed DH charge correlations, and, when combined with the GDH analysis of the density correlations, leaves the GDH theory as the only complete description of ionic correlation functions, as judged by i)-iii), iv) exact low-density (rho(N),T) variation, and v) reasonable behavior near criticality. C1 UNIV MARYLAND,INST PHYS SCI & TECHNOL,COLLEGE PK,MD 20742. RP Lee, BP (reprint author), NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 18 TC 45 Z9 45 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 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD SEP 15 PY 1997 VL 39 IS 6 BP 611 EP 616 DI 10.1209/epl/i1997-00402-x PG 6 WC Physics, Multidisciplinary SC Physics GA XX544 UT WOS:A1997XX54400006 ER PT J AU Angelopoulos, V Phan, TD Larson, DE Mozer, FS Lin, RP Tsuruda, K Hayakawa, H Mukai, T Kokubun, S Yamamoto, T Williams, DJ McEntire, RW Lepping, RP Parks, GK Brittnacher, M Germany, G Spann, J Singer, HJ Yumoto, K AF Angelopoulos, V Phan, TD Larson, DE Mozer, FS Lin, RP Tsuruda, K Hayakawa, H Mukai, T Kokubun, S Yamamoto, T Williams, DJ McEntire, RW Lepping, RP Parks, GK Brittnacher, M Germany, G Spann, J Singer, HJ Yumoto, K TI Magnetotail flow bursts: association to global magnetospheric circulation, relationship to ionospheric activity and direct evidence for localization SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLASMA SHEET; SIGNATURES; EXPANSION; ONSET AB A series of bursty bulk flow events (BBFs) were observed by GEOTAIL and WIND in the geomagnetotail. IMP8 at the solar wind showed significant energy coupling into the magnetosphere, while the WI instrument on POLAR evidenced significant energy transfer to the ionosphere during two substorms. There was good correlation between BBFs and ionospheric activity observed by UVI even when ground magnetic signatures were absent, suggesting that low ionospheric conductivity at the active sector may be responsible for this observation. During the second substorm no significant flux transport was evidenced past WIND in stark contrast to GEOTAIL and despite the small intersatellite separation ((3.54, 2.88, -0.06) R-E). Throughout the intervals studied there were significant differences in the individual flow bursts at the two satellites, even during longitudinally extended ionospheric activations. We conclude that the half-scale-size of transport-bearing flow bursts is less than 3 R-E. C1 UNIV WASHINGTON,GEOPHYS PROGRAM,SEATTLE,WA 98195. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. NAGOYA UNIV,SOLAR TERR ENVIRONM LAB,TOYOKAWA 442,JAPAN. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. NOAA,SPACE ENVIRONM CTR,RESE,BOULDER,CO 80303. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. KYUSHU UNIV,FAC SCI 33,DEPT EARTH & PLANETARY SCI,FUKUOKA 81281,JAPAN. UNIV ALABAMA,CSPAR,HUNTSVILLE,AL 35899. RP Angelopoulos, V (reprint author), UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720, USA. NR 11 TC 136 Z9 139 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 SEP 15 PY 1997 VL 24 IS 18 BP 2271 EP 2274 DI 10.1029/97GL02355 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XW963 UT WOS:A1997XW96300003 ER PT J AU Xue, S Reiff, PH Onsager, TG AF Xue, S Reiff, PH Onsager, TG TI Mid-altitude modeling of cusp ion injection under steady and varying conditions SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLASMA INJECTION; MAGNETOSPHERE; DIPOLE; FIELD AB A cusp ion injection model incorporating mutually consistent electric and magnetic fields is developed. We have simulated cusp ion energy-latitude spectrograms for paths similar to certain orbits of DE-1 and Viking. Both the large-scale energy-latitude dispersion and the embedded small-scale energy-pit ch-angle V signatures are clearly evident in these simulated spectrograms. Our results show that a much narrower V microsignature is obtained when the ion injection source is restricted to a small region. However, the cutoff; of the plasma injection at the magnetosheath sonic line alone also yields relatively narrow V's, without restricting the injection region. This effect is most noticeable in winter conditions. By introducing a time-dependent magnetosheath plasma density variation along the magnetopause to our cusp model, we are also able to reproduce a well observed meso-scale ion injection pattern which can appear to be the overlap of multiple injections, even with assuming steady interconnection. C1 NOAA, RESE, SPACE ENVIRONM CTR, BOULDER, CO 80303 USA. RP Xue, S (reprint author), RICE UNIV, DEPT SPACE PHYS & ASTRON, MS 108, HOUSTON, TX 77005 USA. RI Reiff, Patricia/D-2564-2014 OI Reiff, Patricia/0000-0002-8043-5682 NR 14 TC 13 Z9 13 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD SEP 15 PY 1997 VL 24 IS 18 BP 2275 EP 2278 DI 10.1029/97GL02185 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XW963 UT WOS:A1997XW96300004 ER PT J AU Kemner, KM Harris, VG Elam, WT Feng, YC Laughlin, DE Woicik, JC Lodder, JC AF Kemner, KM Harris, VG Elam, WT Feng, YC Laughlin, DE Woicik, JC Lodder, JC TI Preferential site distribution of dilute Pt and ta in CoCr-based films: An extended x-ray absorption fine structure study SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LONGITUDINAL RECORDING MEDIA; MAGNETIC-PROPERTIES; THIN-FILM; COMPOSITIONAL SEPARATION; CR; ANISOTROPY; SEGREGATION; DEPENDENCE AB Extended x-ray absorption fine structure (EXAFS) measurements of Co78Cr22, Co86Cr12Ta2, and Co86Cr12Pt2 films were made to investigate the local structure and chemistry around Ta and Pt atoms to determine their site distributions in these alloys. Comparisons between the measured data and data collected from experimental standards and calculated using theoretical EXAFS simulation codes indicate that the Ta atoms are preferentially distributed to the Cr-enriched regions of the CoCr media, and the Pt atoms have an effect on the local environment of the Co atoms, Both Ta and Pt introduce a large amount of local structural disorder to the local environments in which they reside. The presence of Ta atoms in the Cr-enriched regions further reduces the magnetization of these regions, which enhances the magnetic isolation of the Co regions from each other. This helps improve the noise characteristics of the films. The portion of the Pt atoms residing in the Go-enriched regions increases the magnetic anisotropy of the films, thereby increasing their coercivity. (C) 1997 American Institute of Physics. C1 USN,RES LAB,WASHINGTON,DC 20375. CARNEGIE MELLON UNIV,DEPT MAT SCI & ENGN,PITTSBURGH,PA 15213. NIST,GAITHERSBURG,MD 20899. UNIV TWENTE,MESA RES INST,NL-7500 AE ENSCHEDE,NETHERLANDS. RI Harris, Vincent/A-8337-2009 NR 24 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 15 PY 1997 VL 82 IS 6 BP 2912 EP 2917 DI 10.1063/1.366124 PG 6 WC Physics, Applied SC Physics GA XX996 UT WOS:A1997XX99600027 ER PT J AU Papanikolas, JM Williams, RM Leone, SR AF Papanikolas, JM Williams, RM Leone, SR TI Manipulation of rovibrational wave packet composition in the Li-2 E((1)Sigma(+)(g)) shelf state using intermediate state selection and shaped femtosecond laser pulses SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DYNAMICS; COHERENT; PHASE; SPECTROSCOPY; SYSTEMS; MOTION AB The composition of a rovibrational wave packet in the E((1) Sigma(g)(+)) state of Li-2 is controlled using a combination of intermediate state selection and femtosecond optical pulse shaping techniques. Intermediate state selection is accomplished using a cw laser to prepare a steady state population of a single rovibrational level in the A((1) Sigma(u)(+)) state of Li-2, which acts as the initial state for subsequent ultrafast pump/probe studies in the ''shelf'' region of the E((1) Sigma(g)(+)) state, An initial set of relative amplitudes of the wave packet eigenstates is defined by the intermediate level. Femtosecond optical pulse shaping, performed using a grating pair and a mechanical amplitude mask, is then used to further alter the wave packet composition. Quantitative changes in the Fourier transform of the pump/probe transient demonstrate that combining these two techniques can be a facile approach to manipulating wave packet composition, with the ultimate goal of controlling wave packet evolution into a desired final form. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Papanikolas, JM (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 31 TC 21 Z9 21 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 SEP 15 PY 1997 VL 107 IS 11 BP 4172 EP 4178 DI 10.1063/1.474141 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XW119 UT WOS:A1997XW11900008 ER PT J AU JakobChien, R Alpert, BK AF JakobChien, R Alpert, BK TI A fast spherical filter with uniform resolution SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID SHALLOW-WATER EQUATIONS; FOURIER-TRANSFORMS; FAST ALGORITHM; TEST SET; EXPANSIONS AB This paper introduces a fast algorithm for obtaining a uniform resolution representation of a function known at a latitude-longitude grid on the surface of a sphere, equivalent to a triangular, isotropic truncation of the spherical harmonic coefficients for the function. The proposed spectral truncation method, which is based on the fast multipole method and the fast Fourier transform, projects the function to a space with uniform resolution while avoiding surface harmonic transformations. The method requires O(N-2 log N) operations for O(N-2) grid points, as opposed to O(N-3) operations for the standard spectral transform method, providing a reduced-complexity spectral method obviating the pole problem in the integration of time-dependent partial differential equations on the sphere. The filter's performance is demonstrated with numerical examples. (C) 1997 Academic Press. C1 UNIV COLORADO,DEPT COMP SCI & ENGN,DENVER,CO 80202. NATL INST STAND & TECHNOL,DEPT COMMERCE,BOULDER,CO 80303. NR 15 TC 55 Z9 56 U1 2 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD SEP 15 PY 1997 VL 136 IS 2 BP 580 EP 584 DI 10.1006/jcph.1997.5782 PG 5 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XZ450 UT WOS:A1997XZ45000023 ER PT J AU AceroSchertzer, CE Hansen, DV Swenson, MS AF AceroSchertzer, CE Hansen, DV Swenson, MS TI Evaluation and diagnosis of surface currents in the National Centers for Environmental Prediction's ocean analyses SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID GENERAL-CIRCULATION MODEL; TROPICAL PACIFIC-OCEAN; DATA ASSIMILATION SYSTEM; EQUATORIAL PACIFIC; ATLANTIC-OCEAN; DRIFTING BUOY; WIND STRESS; SEA-LEVEL; VARIABILITY; TEMPERATURE AB Ensemble average currents from the 15 m depth level of the National Centers for Environmental Prediction's (NCEP) analyses of the tropical Pacific Ocean are evaluated against surface mixed layer current observations obtained from an extensive set of satellite-tracked drifting buoys. These averages display many climatological characteristics of the region but are not intended to serve as a climatology because the data from the analyses are trimmed to match the time-space distribution of the observations. Substantial discrepancies between the analyses and the observations are revealed. First, the near-equatorial meridional currents and divergence have approximately twice the magnitude in the analyses as in the observations. This discrepancy is largely independent of whether temperature profile data art assimilated or not and is attributed to the parameterization of vertical viscosity. Second, the zonal flow in both the North Equatorial Countercurrent (NECC) and the South Equatorial Current (SEC) is much stronger in the analyses than in the observations, especially in the western Pacific. This discrepancy is associated with assimilation of temperature profile data. It arises because salinity is an active variable in the underlying analysis model but is not controlled by boundary fluxes or other observations. Under the uncontrolled influence of advection and strong horizontal diffusion the salinity distribution becomes nearly homogeneous. Consequently, the analyses do not account for observed temperature-salinity correlations when density is computed following assimilation of temperature profile data. This leads to erroneous pressure gradients that drive excessively strong geostrophic currents and force large accelerations near the western boundary. Our results indicate that it is important to consider the consequences on the density structure of neglecting salinity during the assimilation of temperature data. We recommend that surface salinity observations from drifting buoys and volunteer observing ships be initiated to improve the ocean analyses. C1 UNIV MIAMI,COOPERAT INST MARINE & ATMOSPHER STUDIES,MIAMI,FL 33149. NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33149. NR 59 TC 27 Z9 27 U1 0 U2 0 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 SEP 15 PY 1997 VL 102 IS C9 BP 21037 EP 21048 DI 10.1029/97JC01584 PG 12 WC Oceanography SC Oceanography GA XX061 UT WOS:A1997XX06100009 ER PT J AU Douglas, JF Schneider, HM Frantz, P Lipman, R Granick, S AF Douglas, JF Schneider, HM Frantz, P Lipman, R Granick, S TI The origin and characterization of conformational heterogeneity in adsorbed polymer layers SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID RANDOM SEQUENTIAL ADSORPTION; POLY(METHYL METHACRYLATE); IRREVERSIBLE ADSORPTION; KINETIC TRAPS; MONTE-CARLO; DESORPTION; INTERFACE; EXCHANGE; POLYSTYRENE; DENSITY AB The equilibration of polymer conformations tends to be sluggish in polymer layers adsorbed onto highly attractive substrates, so the structure of these layers must be understood in terms of the layer growth process rather than equilibrium theory. Initially adsorbed chains adopt a highly Battened configuration while the chains which arrive later must adapt their configurations to the increasingly limited space available for adsorption. Thus, the chains adsorbed in the late stage of deposition are more tenuously attached to the surface. This type of non-equilibrium growth process is studied for polymethylmethacrylate (PMMA) adsorbed on oxidized silicon where the segmental attraction is strong (4 k(B) T/segment) and for polystyrene (PS) adsorbed on oxidized silicon from a carbon tetrachloride solution where the segmental attraction is relatively weak (1 k(B)T/segment). Measurements were based on Fourier transform infrared spectroscopy in attenuated total reflection (FTIR-ATR). In both cases, the chains arriving first adsorbed more tightly, became flattened (as measured by the dichroic ratio), and occupied a disproportionately large fraction of the surface. This non-uniform structure persisted indefinitely for the strongly adsorbed PMMA chains, while the PS chains exhibited a gradual evolution, presumably reflecting an equilibration of the adsorbed layer occurring after long times. On the theoretical side, the initial heterogeneity of these adsorbed polymer layers is modelled using a random sequential adsorption (RSA) model where the size of the adsorbing species is allowed to adapt to the surface space available at the time of adsorption. The inhomogeneity in the size of adsorbing species (hemispheres) in this model is similar to the distribution of chain contacts in our measurements on adsorbed polymer layers. Owing to extensive variance around the mean, conformations having the mean number of chain contacts are least probable, which contrasts starkly with expectations based on equilibrium adsorption theory. C1 UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801. NIST,APPL & COMPUTAT MATH DIV,GAITHERSBURG,MD 20899. RP Douglas, JF (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 45 TC 63 Z9 63 U1 1 U2 15 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD SEP 15 PY 1997 VL 9 IS 37 BP 7699 EP 7718 DI 10.1088/0953-8984/9/37/005 PG 20 WC Physics, Condensed Matter SC Physics GA XW789 UT WOS:A1997XW78900005 ER PT J AU Kinne, S Akerman, TP Shiobara, M Uchiyama, A Heymsfield, AJ Miloshevich, L Wendell, J Eloranta, EW Purgold, C Bergstrom, RW AF Kinne, S Akerman, TP Shiobara, M Uchiyama, A Heymsfield, AJ Miloshevich, L Wendell, J Eloranta, EW Purgold, C Bergstrom, RW TI Cirrus cloud radiative and microphysical properties from ground observations and in situ measurements during FIRE 1991 and their application to exhibit problems in cirrus solar radiative transfer modeling SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ICE CRYSTALS; OPTICAL-PROPERTIES; SCATTERING; CLIMATE; LIGHT; PARAMETERIZATION; TEMPERATURE; AIRCRAFT; FEEDBACK AB Measurements from the FIRE 1991 cirrus cloud field experiment in the central United States are presented and analyzed. The first part focuses on cirrus microphysical properties. Aircraft 2D-probe in situ data at different cloud altitudes were evaluated for cirrus cases on four different days. Also presented are simultaneous data samples from balloonborne videosondes. Only these balloonsondes could detect the smaller crystals. Their data suggest (at least for midlatitude altitudes below 10 km) that ice crystals smaller than 15 mu m in size are rare and that small ice crystals not detected by 2D-probe measurements are radiatively of minor importance, as overlooked 2D-probe crystals account for about 10% of the total extinction. The second part focuses on the link between cirrus cloud properties and radiation. With cloud microphysical properties from surface remote sensing added to the microphysical data and additional radiation measurements at the surface, testbeds for radiative transfer models were created. To focus on scattering processes, model evaluations were limited to the solar radiative transfer by comparing calculated and measured transmissions of sunlight at the surface. Comparisons under cloud-free conditions already reveal a model bias of about +45 W m(-2) for the hemispheric solar downward broadband flux. This discrepancy, which is (at least in part) difficult to explain. has to be accounted for in comparisons involving clouds. Comparisons under cirrus cloud conditions identify as the major obstacle in cirrus solar radiative transfer modeling the inability of one-dimensional radiative transfer models to account for horizontal inhomogeneities. The successful incorporation of multidimensional radiative transfer effects will depend not only on better models but critically on the ability to measure and to define characteristic inhomogeneity scales of cloud fields. The relative minor error related to the microphysical treatment is in part a reflection of the improved understanding on solar scattering on ice crystals over the last decade and of the available wealth on ice-crystal size and shape data for this study. In absence of this information, uncertainties from microphysical cirrus model assumptions will remain high. C1 PENN STATE UNIV,DEPT METEOROL,UNIVERSITY PK,PA 16802. METEOROL RES INST,TSUKUBA,IBARAKI 305,JAPAN. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. NOAA,BOULDER,CO. UNIV WISCONSIN,DEPT ATMOSPHER SCI,MADISON,WI. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. BAY AREA ENVIRONM RES INST,SAN FRANCISCO,CA. RP Kinne, S (reprint author), NASA,AMES RES CTR,BAY AREA ENVIRONM RES INST,MAILSTOP 245-4,MOFFETT FIELD,CA 94035, USA. RI Heymsfield, Andrew/E-7340-2011 NR 37 TC 44 Z9 44 U1 0 U2 1 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 SEP 15 PY 1997 VL 54 IS 18 BP 2320 EP 2344 DI 10.1175/1520-0469(1997)054<2320:CCRAMP>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XW339 UT WOS:A1997XW33900006 ER PT J AU Braun, RJ Cahn, JW McFadden, GB Wheeler, AA AF Braun, RJ Cahn, JW McFadden, GB Wheeler, AA TI Anisotropy of interfaces in an ordered alloy: a multiple-order-parameter model SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article ID PHASE-FIELD MODEL; VECTOR THERMODYNAMICS; ANTIPHASE BOUNDARIES; BINARY-ALLOYS; FCC ALLOYS; GROWTH; TRANSITIONS; SURFACES; DYNAMICS; MOTION AB A multiple-order-parameter theory of ordering on a binary face-centred-cubic (FCC) crystal lattice is developed, and adapted to provide a continuum formulation that incorporates the underlying symmetries of the FCC crystal in both the bulk and gradient-energy terms of the free energy. The theory is used to compute the orientation dependence of the structure and energy of interphase and antiphase boundaries. The structure of these interfaces compares favourably with previous lattice calculations by Kikuchi & Cahn (1962, 1979). Anisotropy is a natural consequence of the lattice calculation and the multiple-order-parameter continuum formulation presented here. This is in contrast to the ad hoc fashion in which anisotropy is often introduced into a single-order-parameter continuum theory. C1 UNIV DELAWARE, DEPT MATH SCI, NEWARK, DE 19716 USA. UNIV SOUTHAMPTON, FAC MATH STUDIES, SOUTHAMPTON SO17 1BJ, HANTS, ENGLAND. RP NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. RI McFadden, Geoffrey/A-7920-2008 OI McFadden, Geoffrey/0000-0001-6723-2103 NR 65 TC 48 Z9 49 U1 2 U2 12 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X EI 1471-2962 J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD SEP 15 PY 1997 VL 355 IS 1730 BP 1787 EP 1833 PG 47 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XW796 UT WOS:A1997XW79600003 ER PT J AU Shirley, EL Zhu, XJ Louie, SG AF Shirley, EL Zhu, XJ Louie, SG TI Core polarization in solids: Formulation and application to semiconductors SO PHYSICAL REVIEW B LA English DT Article ID QUASI-PARTICLE ENERGIES; NORM-CONSERVING PSEUDOPOTENTIALS; MONTE-CARLO; QUASIPARTICLE ENERGIES; BAND STRUCTURES; BRILLOUIN-ZONE; SPECIAL POINTS; SILICON; ELECTRON; EXCHANGE AB Accurate treatment of exchange and correlation effects involving core and valence electrons can he surprisingly important in solid-state calculations, especially for solids having elements with shallow core electrons, such as Ga and Ge. A local-density-approximation treatment of core-valence interactions leads to errors of similar to 0.4 eV for key features in the band structures of Ge and GaAs, even when valence-valence interactions are treated in a first-principles, quasiparticle approach. We apply a core-polarization-potential treatment of corevalence interactions within the framework of such quasiparticle calculations. Final results have errors of similar to 0.1 eV in band-energy differences. C1 UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV MAT SCI, BERKELEY, CA 94720 USA. RP NIST, DIV OPT TECHNOL, GAITHERSBURG, MD 20899 USA. NR 68 TC 52 Z9 52 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 1997 VL 56 IS 11 BP 6648 EP 6661 DI 10.1103/PhysRevB.56.6648 PG 14 WC Physics, Condensed Matter SC Physics GA XY806 UT WOS:A1997XY80600048 ER PT J AU Jimenez, I Terminello, LJ Sutherland, DGJ Carlisle, JA Shirley, EL Himpsel, FJ AF Jimenez, I Terminello, LJ Sutherland, DGJ Carlisle, JA Shirley, EL Himpsel, FJ TI Accurate valence band width of diamond SO PHYSICAL REVIEW B LA English DT Article ID PHOTOELECTRON ANGULAR-DISTRIBUTIONS; FERMI-SURFACE; QUASIPARTICLE ENERGIES; ELECTRON; METALS; STATES; SEMICONDUCTORS; GRAPHITE; PHOTOEMISSION; INSULATORS AB An accurate width is determined,for the valence band of diamond by imaging photoelectron momentum distributions for a variety of initial-and final-state energies. The experimental result of 23.0+/-0.2 eV(2) agrees well with first-principles quasiparticle calculations (23.0 and 22.88 eV) and significantly exceeds the local-density-functional width, 21.5+/-0.2 eV(2). This difference quantifies effects of creating an excited hole state (with associated many-body effects) in a band measurement vs studying ground-state properties treated by local-density-functional calculations. C1 NIST, OPT TECHNOL DIV, GAITHERSBURG, MD 20899 USA. UNIV WISCONSIN, DEPT PHYS, MADISON, WI 53706 USA. RP LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. RI Jimenez, Ignacio/F-7422-2010 OI Jimenez, Ignacio/0000-0001-5605-3185 NR 31 TC 43 Z9 44 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 1997 VL 56 IS 12 BP 7215 EP 7221 DI 10.1103/PhysRevB.56.7215 PG 7 WC Physics, Condensed Matter SC Physics GA YA575 UT WOS:A1997YA57500031 ER PT J AU Zimmerman, NM Cobb, JL Clark, AF AF Zimmerman, NM Cobb, JL Clark, AF TI Modulation of the charge of a single-electron transistor by distant defects SO PHYSICAL REVIEW B LA English DT Article ID NOISE AB We have systematically measured two-level fluctuator (TLF) noise in a single-electron tunneling transistor. From the amplitude, duty cycle, and presence of intermediate states, we conclude that there is a cluster of triggered TLF's in this case. The systematic dependence of switching rate on gate voltage, and the lack of rate dependence on a finer scale or on source-drain voltage, tell us unambiguously that the TLF's are not located in the tunnel barriers. We thus conclude, as has been previously inferred, that noisy defects outside the barrier can lead to significant modulation of the transistor island charge (up to about 0.2 e). C1 NIST,GAITHERSBURG,MD 20899. NR 10 TC 50 Z9 50 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 SEP 15 PY 1997 VL 56 IS 12 BP 7675 EP 7678 DI 10.1103/PhysRevB.56.7675 PG 4 WC Physics, Condensed Matter SC Physics GA YA575 UT WOS:A1997YA57500085 ER PT J AU Hassanzadeh, P Irikura, KK Johnson, RD AF Hassanzadeh, P Irikura, KK Johnson, RD TI Ab initio ionization and excitation spectra involving IO(X-2 Pi) and IO+(X-3 Sigma(-), a(1)Delta, b(1)Sigma(+)) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID QUADRATIC CONFIGURATION-INTERACTION; LEVEL-CORRELATED CALCULATIONS; MOLECULAR ELECTRIC PROPERTIES; POLARIZED BASIS-SETS; COUPLED-CLUSTER SINGLES; PHOTOELECTRON-SPECTROSCOPY; OZONE DEPLETION; HIGH-RESOLUTION; IO; IODINE AB An equilibrium bond length of r(e) = 1.894 Angstrom and harmonic vibrational frequency of omega(e) = 664 cm(-1) are computed for IO(X-2 Pi) at the nonrelativistic all-electron CCSD(T)/6-311+G(3df) level of theory. These are within 1% of the experimental Omega-averaged values of 1.877 +/- 0.005 Angstrom (3 sigma) and 670 +/- 13 cm(-1) (3 sigma), respectively. Similar calculations predict r(e)=1.824 Angstrom and omega(e)=764 cm(-1) for IO+ (X-3 Sigma(-)). For the singlet excited electronic states of IO+, which require a multireference treatment, CASPT2(8,6)/6-311+G(3df) predicts r(e)=1.841 Angstrom and omega(e)=738 cm(-1) for IO+(a(1) Delta) and r(e)=1.870 Angstrom and omega(e)=679 cm(-1) for IO+(b(1) Sigma(+)). The equilibrium bond length increases and the harmonic vibrational frequency decreases from the ground to the excited states of IO+ as observed for the isovalent O-2 molecule. A spin-spin splitting of 1060 +/- 160 cm(-1) (3 sigma) is assigned to the two sublevels of the ground state of iodine monoxide cation, IO+ (X-1(3) Sigma(0)(-), X-2(3) Sigma(+/-1)(-)), on the basis of a reinterpretation of an experimental photoionization efficiency spectrum of IO. This reassignment is required by the present vibrational constants for IO+, Franck-Condon factors, and four-component, relativistic multireference configuration interaction (CI) calculations of the spin-spin splitting. An adiabatic ionization energy of 9.60 eV is computed at the CCSD(T) level of theory for the IO+(X-3 Sigma(0)(-)) <-- IO(X-2 Pi(3/2)) transition and is in reasonable agreement with the experimental photo-ionization threshold of 9.735 +/- 0.017 eV (3 sigma). Adiabatic excitation energies of 0.72 and 1.18 eV are calculated at the CASPT2 level of theory for IO+(a(1) Delta) <-- IO+(X-3 Sigma(0)(-)) and IO+(b(1) Sigma(+)) <-- IO+(X-3 Sigma(0)(-)) transitions, respectively. The photoionization spectrum of IO and excitation spectrum of IO+ have also been simulated. C1 NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 NR 35 TC 3 Z9 3 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 SEP 11 PY 1997 VL 101 IS 37 BP 6897 EP 6902 DI 10.1021/jp971007e PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XW315 UT WOS:A1997XW31500014 ER PT J AU Banerjee, S Shigematsu, N Pannell, LK Ruvinov, S Orban, J Schwarz, F Herzberg, O AF Banerjee, S Shigematsu, N Pannell, LK Ruvinov, S Orban, J Schwarz, F Herzberg, O TI Probing the non-proline cis peptide bond in beta-lactamase from Staphylococcus aureus PC1 by the replacement Asn136->Ala SO BIOCHEMISTRY LA English DT Article ID SITE-DIRECTED MUTAGENESIS; ACYL-ENZYME INTERMEDIATE; BACILLUS-LICHENIFORMIS 749/C; REFINED CRYSTAL-STRUCTURE; ESCHERICHIA-COLI; 6-BETA-BROMOPENICILLANIC ACID; FOLDING PATHWAY; ACTIVE-SITE; RESOLUTION; MECHANISM AB A non-proline cis peptide is present between Glu166 and Ile167 in the active site of beta-lactamase from Staphylococcus nul eus PC1. To examine the role of the interaction between the side chain of Asn136 and the main chain of Glu166, the site-directed mutant N136A was produced. The enzyme shows no measurable hydrolytic activity toward a variety of penicillins or cephalosporins except for the chromogenic cephalosporin, nitrocefin. For nitrocefin, the progress curve exhibits a fast burst with a stoichiometry of 1 mol of degraded substrate per mole of enzyme followed by a slow phase with a hydrolysis rate that is reduced by approximately 700-fold compared with that of the wild-type enzyme. Thus, the mutant enzyme is deacylation defective. Monitoring the hydrolysis of nitrocefin after preincubation with a number of beta-lactam compounds shows that cephalosporins form stable acyl complexes with the enzyme, whereas penicillins do not. The molecular weight of the mutant was determined by electrospray mass spectrometry, and the presence of the stable acyl enzyme adducts with cephaloridine and cefotaxime was confirmed by both electrospray and MALDI mass spectrometry. Therefore, in addition to impairing deacylation, the acylation machinery has been altered compared with the wild-type enzyme to act on cephalosporins and not on penicillins. Urea denaturation and thermal unfolding studies show that the N136A mutant enzyme is less stable than the wild-type enzyme. However, stability against chemical denaturation of the mutant enzyme is enhanced in the presence of cephaloridine beyond the stability of the wild-type protein. This is attributed to accumulation of favorable interactions between the cephaloridine and the protein, which play a role in the folded state and not in the unfolded state. C1 UNIV MARYLAND,MARYLAND BIOTECHNOL INST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NIST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NIDDK,BIOORGAN CHEM LAB,NIH,BETHESDA,MD 20892. RI Shigematsu, Naoyuki/B-9374-2014 FU NIAID NIH HHS [R01-AI27175] NR 49 TC 8 Z9 8 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD SEP 9 PY 1997 VL 36 IS 36 BP 10857 EP 10866 DI 10.1021/bi970352r PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XV538 UT WOS:A1997XV53800009 PM 9283075 ER PT J AU Stockman, PA Blake, GA Lovas, FJ Suenram, RD AF Stockman, PA Blake, GA Lovas, FJ Suenram, RD TI Microwave rotation-tunneling spectroscopy of the water-methanol dimer: Direct structural proof for the strongest bound conformation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INFRARED-LASER SPECTROSCOPY; INTERMOLECULAR VIBRATION; DIPOLE-MOMENT; SPECTRUM; COMPLEXES; DYNAMICS; BARRIER; CLUSTERS; AMMONIA; TRIMERS AB Rotation-Tunneling a-type spectra of CH3OH...H2O and CH3OD...D2O were recorded between 18 and 60 GHz using direct absorption microwave spectroscopy, and for CH3OH...H2O, (CH3OH)-C-13...H2O, CH3OH...DOH, CD3OH...H2O, and CH3OD...D2O between 7 and 24 GHz using a Fourier-transform microwave spectrometer. Because CH3OH and H2O are capable of both accepting and donating hydrogen bonds, there exists some question as to which donor-acceptor pairing of the molecules is the lowest energy form. This question is further emphasized by the ambiguity and variety present in previous experimental and computational results. Transitions arising from the methyl torsional A state were assigned in each of the studied isotopomers, and for the A and E states in CH3OH...H2O. While the measured components of the dipole moment for the parent (H,C-12,O-16) isotopomer-mu(a)=7.956+/-0.03x10(-30) C m (2.385+/-0.008 D), mu(b)=3.636 +/-0.02x10(-30) C m (1.090+/-0.006 D), mu(c)=0.43+/-0.47x10(-30) C m (0.13+/-0.14 D), where the errors correspond to 1 sigma uncertainties-are consistent with either conformation, the fit of the structure to the rotational constants demonstrates unambiguously that the lower-energy conformation formed in supersonically cooled molecular beams corresponds to a water-donor, methanol-acceptor complex. The results and implications for future work are also discussed in terms of the permutation-inversion theory presented by Hougen and Ohashi [J. Mol. Spectros. 159, 363 (1993)]. (C) 1997 American Institute of Physics. C1 CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. NIST,DIV OPT TECHNOL,GAITHERSBURG,MD 20899. NR 51 TC 63 Z9 64 U1 2 U2 12 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 SEP 8 PY 1997 VL 107 IS 10 BP 3782 EP 3790 DI 10.1063/1.474736 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XV756 UT WOS:A1997XV75600005 ER PT J AU Mountain, RD AF Mountain, RD TI Shear viscosity and dielectric constant of liquid acetonitrile SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; COMPUTER-SIMULATION; POLARIZABILITY ANISOTROPY; METHYL CYANIDE; MODEL; PRESSURE; SOLVATION; CLUSTERS; WATER AB Molecular dynamics has been used to evaluate the predictions for the coefficient of shear viscosity and for the dielectric constant for three-site models of acetonitrile as these properties are import ant when simulating processes in mixtures. The model of Edwards et al. [Mel. Phys. 51, 1141 (1984)] provides a value for the shear viscosity that is close to the experimental value and a value for the dielectric constant that is about 18% less than the experimental value. The model of Jorgensen and Briggs [Mol. Phys. 63, 547 (1988)] provides values that have larger deviations from the experimental values. The model of Edwards ef al. is recommended as the three-site model of acetonitrile to use in simulations of mixtures. RP Mountain, RD (reprint author), NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899, USA. NR 31 TC 31 Z9 31 U1 3 U2 10 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 SEP 8 PY 1997 VL 107 IS 10 BP 3921 EP 3923 DI 10.1063/1.474767 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XV756 UT WOS:A1997XV75600021 ER PT J AU Hammouda, B Balsara, NP Lefebvre, AA AF Hammouda, B Balsara, NP Lefebvre, AA TI Small-angle neutron scattering from pressurized polyethylbutylene/polymethylbutylene blends SO MACROMOLECULES LA English DT Article ID SPINODAL DECOMPOSITION; POLYMER BLENDS; MIXTURES; DISSOLUTION C1 POLYTECH INST NEW YORK, DEPT CHEM ENGN, METROTECH CTR 6, BROOKLYN, NY 11201 USA. RP Hammouda, B (reprint author), NIST, BLDG 235, ROOM E151, GAITHERSBURG, MD 20899 USA. NR 6 TC 32 Z9 34 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD SEP 8 PY 1997 VL 30 IS 18 BP 5572 EP 5574 DI 10.1021/ma970673a PG 3 WC Polymer Science SC Polymer Science GA XV577 UT WOS:A1997XV57700055 ER PT J AU Slomkowski, S Miksa, B Kowalczyk, D Basinska, T AF Slomkowski, S Miksa, B Kowalczyk, D Basinska, T TI Proteins at surfaces of poly(styrene/acrolein) latexes and latex assemblies. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 POLISH ACAD SCI,CTR MOL & MACROMOL STUDIES,PL-90363 LODZ,POLAND. NIST,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 SEP 7 PY 1997 VL 214 BP 1 EP MACR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901674 ER PT J AU Poirier, GE AF Poirier, GE TI Scanning tunneling microscopy of alkanethiol monolayers on AU(111). 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 SEP 7 PY 1997 VL 214 BP 10 EP MTLS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901741 ER PT J AU Stansbury, JW Choi, KM Antonucci, JM AF Stansbury, JW Choi, KM Antonucci, JM TI Considerations in the development of semifluorinated methacrylate dental resins and composites. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 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 SEP 7 PY 1997 VL 214 BP 15 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900949 ER PT J AU Ermi, BD Karim, A Douglas, JF Sung, LP AF Ermi, BD Karim, A Douglas, JF Sung, LP TI Atomic forge microscopy investigations of phase separation in ultrathin polymer blend films. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV POLYMERS,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 SEP 7 PY 1997 VL 214 BP 16 EP MACR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901689 ER PT J AU Nandi, S Sanov, A Lineberger, WC AF Nandi, S Sanov, A Lineberger, WC TI The photodissociation dynamics of solvated molecular cluster ions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NATL INST STAND & TECHNOL,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 SEP 7 PY 1997 VL 214 BP 31 EP PHYS PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900549 ER PT J AU Steel, AB Cheek, B Miller, CJ AF Steel, AB Cheek, B Miller, CJ TI Monolayer flow: A new surface characterization method. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV MARYLAND,COLLEGE PK,MD 20742. NIST,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 SEP 7 PY 1997 VL 214 BP 34 EP MTLS PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901765 ER PT J AU Bowen, RL AF Bowen, RL TI Preparation of a beta-cyclodextrin methacrylate. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,AMER DENT ASSOC HLTH FDN,PAFFENBARGER RES CTR,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 SEP 7 PY 1997 VL 214 BP 36 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900970 ER PT J AU Topp, A Bauer, BJ Amis, EJ Scherrenberg, R AF Topp, A Bauer, BJ Amis, EJ Scherrenberg, R TI Small angle neutron scattering from dilute and concentrated DAB(PA)x dendrimer solutions SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20899. DSM RES BV,NL-6160 MD GELEEN,NETHERLANDS. 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 SEP 7 PY 1997 VL 214 BP 37 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901299 ER PT J AU Lin, EK Wu, WL Satija, SK AF Lin, EK Wu, WL Satija, SK TI Measuring polymer dynamics near the polymer-solid interface with neutron reflectometry. 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 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 SEP 7 PY 1997 VL 214 BP 39 EP MACR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901712 ER PT J AU Bauer, BJ Topp, A Prosa, TJ Amis, EJ AF Bauer, BJ Topp, A Prosa, TJ Amis, EJ TI SANS and SAXS investigations of the internal structure of dendritic molecules SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20899. MICHIGAN MOL INST,MIDLAND,MI 48640. 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 SEP 7 PY 1997 VL 214 BP 40 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901302 ER PT J AU Reed, BB Choi, K Dickens, SH Stansbury, JW AF Reed, BB Choi, K Dickens, SH Stansbury, JW TI Effect of resin composition on kinetics of dimethacrylate photopolymerization. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 ADA HLTH FDN,GAITHERSBURG,MD 20899. NIST,GAITHERSBURG,MD 20899. NR 0 TC 1 Z9 1 U1 1 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 SEP 7 PY 1997 VL 214 BP 41 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900975 ER PT J AU Satija, SK Gallagher, PD Karim, A Fetters, LJ AF Satija, SK Gallagher, PD Karim, A Fetters, LJ TI End grafted polystyrene brushes in a critical binary mixture. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 EXXON CORP,ANNANDALE,NJ. NIST,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 SEP 7 PY 1997 VL 214 BP 41 EP MACR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901714 ER PT J AU McDonough, WG Antonucci, JM Dunkers, JP AF McDonough, WG Antonucci, JM Dunkers, JP TI A study of dental adhesion by means of the microbond test. 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 SEP 7 PY 1997 VL 214 BP 43 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900977 ER PT J AU Nguyen, D Clarke, CJ Eisenberg, A Kim, J Satija, S White Shin, K Rafailovich, M Sokolov, J AF Nguyen, D Clarke, CJ Eisenberg, A Kim, J Satija, S White Shin, K Rafailovich, M Sokolov, J TI A neutron reflection study of adsorbed polyelectrolyte random copolymers in mixed solvent. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 MCGILL UNIV,MONTREAL,PQ H3A 2K6H,CANADA. NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899. SUNY STONY BROOK,MSE,STONY BROOK,NY 11794. RI Shin, Kwanwoo /C-4979-2012 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 SEP 7 PY 1997 VL 214 BP 46 EP MACR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901719 ER PT J AU Smeller, JM Beck, CM Butler, TA AF Smeller, JM Beck, CM Butler, TA TI Comparison of visual and potentiometric endpoint determination for the EDTA titration of rare-earth metals SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,CTR ANALYT CHEM,CHEM SCI & TECHNOL LAB,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 SEP 7 PY 1997 VL 214 BP 47 EP ANYL PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ857 UT WOS:A1997XQ85700303 ER PT J AU Misra, DN AF Misra, DN TI Interaction of ortho-phospho-L-serine with hydroxyapatite: Formation of a surface complex. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV POLYMERS,ADAHF PAFFENBARGER RES CTR,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 SEP 7 PY 1997 VL 214 BP 50 EP COLL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ857 UT WOS:A1997XQ85701072 ER PT J AU Douglas, JF Lipman, R Karim, A Granick, S AF Douglas, JF Lipman, R Karim, A Granick, S TI Models of the influence of excluded volume on the formation of polymer layers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. NIST,MATH & COMPUTAT SCI DIV,GAITHERSBURG,MD 20899. UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801. 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 SEP 7 PY 1997 VL 214 BP 51 EP MACR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901724 ER PT J AU Plant, AL Silin, V Hubbard, J Meuse, C AF Plant, AL Silin, V Hubbard, J Meuse, C TI Kinetics and thermodynamics of self assembly of biomimetic hybrid bilayer membranes. 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 SEP 7 PY 1997 VL 214 BP 51 EP MTLS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901782 ER PT J AU Jackson, CL Chanzy, HD Han, CC Balsamo, V vonGyldenfeldt, R Stadler, R AF Jackson, CL Chanzy, HD Han, CC Balsamo, V vonGyldenfeldt, R Stadler, R TI Surface topology and organization of single crystals from polystyrene-polycaprolactone (PS-b-PCL) and PS-polybutadiene-PCL (PS-b-PB-b-PCL) block copolymers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. CERMAV,CNRS,GRENOBLE,FRANCE. UNIV BAYREUTH,BAYREUTH,GERMANY. 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 SEP 7 PY 1997 VL 214 BP 54 EP MACR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901727 ER PT J AU Herne, TM Tarlov, MJ AF Herne, TM Tarlov, MJ TI Structural characterization and hybridization reactions of surface bound, single-stranded DNA. 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 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 SEP 7 PY 1997 VL 214 BP 62 EP MTLS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901793 ER PT J AU Guttman, CM Danis, PO Blair, WR AF Guttman, CM Danis, PO Blair, WR TI Comparison of copolymer distribution using SEC and MALDI TOF MS of SRM 1487, a low molecular weight poly(methyl methacrylate). SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. ROHM & HAAS CO,RES LAB,SPRING HOUSE,PA 19477. NR 0 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 SEP 7 PY 1997 VL 214 BP 90 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901352 ER PT J AU Tan, NB Balogh, L Trevino, S AF Tan, NB Balogh, L Trevino, S TI Structure of metallo-organic nano-composites produced from dendrimer complexes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 USA,RES LAB,AMSRL WM MA,ABERDEEN PROVING GROUND,MD 21005. MICHIGAN MOL INST,MIDLAND,MI 48640. NIST,DIV REACTOR RADIAT,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 SEP 7 PY 1997 VL 214 BP 101 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901363 ER PT J AU Hoobler, RJ Opansky, BJ Leone, SR AF Hoobler, RJ Opansky, BJ Leone, SR TI Laboratory studies of low temperature rate coefficients. 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,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 SEP 7 PY 1997 VL 214 BP 114 EP COLL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ857 UT WOS:A1997XQ85701136 ER PT J AU Longfellow, CA Imamura, T Hanson, DR AF Longfellow, CA Imamura, T Hanson, DR TI Heterogeneous reactions of HONO+HCl with sulfuric acid. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM STUDIES,BOULDER,CO 80309. NATL OCEAN & ATMOSPHER ADM,AERON LAB,BOULDER,CO. 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 SEP 7 PY 1997 VL 214 BP 128 EP COLL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ857 UT WOS:A1997XQ85701150 ER PT J AU Antonucci, JM Fowler, BO Stansbury, JW AF Antonucci, JM Fowler, BO Stansbury, JW TI Facile syntheses of acrylic organosilsesquioxanes for dental applications SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20899. NIDR,NIH,BETHESDA,MD 20982. 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 SEP 7 PY 1997 VL 214 BP 143 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901077 ER PT J AU Kelly, JR Antonucci, M AF Kelly, JR Antonucci, M TI Processing and properties of interpenetrating-phase composites SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. USN,SCH DENT,BETHESDA,MD 20814. 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 SEP 7 PY 1997 VL 214 BP 147 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901081 ER PT J AU Karim, A Liu, DW Bauer, BJ Douglas, JF Amis, EJ AF Karim, A Liu, DW Bauer, BJ Douglas, JF Amis, EJ TI Influence of generation number on the formation of dendrimer monolayers SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. MICHIGAN MOL INST,MIDLAND,MI 48640. 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 SEP 7 PY 1997 VL 214 BP 159 EP PMSE PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901421 ER PT J AU Amis, EJ Topp, A Bauer, BJ AF Amis, EJ Topp, A Bauer, BJ TI SANS study of labeled PAMAM dendrimer SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,GAITHERSBURG,MD 20899. MICHIGAN MOL INST,MIDLAND,MI 48640. 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 SEP 7 PY 1997 VL 214 BP 160 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901422 ER PT J AU Nikaido, T Antonucci, JM Schumacher, GE Code, JE Tagami, J AF Nikaido, T Antonucci, JM Schumacher, GE Code, JE Tagami, J TI Efficacy of N-aryl- and N-alkyliminodiacetic acids in the stabilization of demineralized dentin. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 TOKYO MED & DENT UNIV,TOKYO 113,JAPAN. NIST,GAITHERSBURG,MD 20899. ADAHF,PRC,GAITHERSBURG,MD. 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 SEP 7 PY 1997 VL 214 BP 174 EP POLY PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901108 ER PT J AU Horkay, F McKenna, GB Hecht, AM Geissler, E AF Horkay, F McKenna, GB Hecht, AM Geissler, E TI Scattering and osmotic measurements on polymer solutions and gels. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 GE CO,CORP RES & DEV,SCHENECTADY,NY 12301. NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. UNIV GRENOBLE 1,SPECTROMETRIE PHYS LAB,F-38402 ST MARTIN DHER,FRANCE. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD SEP 7 PY 1997 VL 214 BP 186 EP PMSE PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901448 ER PT J AU Gilson, MK Antosiewicz, J Trylska, J Hodge, CN Klabe, R AF Gilson, MK Antosiewicz, J Trylska, J Hodge, CN Klabe, R TI Binding of protons and cyclic urea inhibitors HIV-1 protease SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NIST,ROCKVILLE,MD 20850. UNIV WARSAW,PL-00325 WARSAW,POLAND. DUPONT MERCK PHARMACEUT CO,WILMINGTON,DE 19880. RI Antosiewicz, Jan/G-1308-2011 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 SEP 7 PY 1997 VL 214 BP 189 EP COMP PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ857 UT WOS:A1997XQ85701388 ER PT J AU Bur, AJ Vangel, MG Roth, SC Johnsonbaugh, DS AF Bur, AJ Vangel, MG Roth, SC Johnsonbaugh, DS TI Real-time resin temperature measurements from fluorescence spectroscopy. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 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 SEP 7 PY 1997 VL 214 BP 192 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901454 ER PT J AU Madura, JD Gilson, M Wierzbicki, A AF Madura, JD Gilson, M Wierzbicki, A TI Molecular dynamics simulation with Poisson-Boltzmann electrostatics. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV S ALABAMA,DEPT CHEM,MOBILE,AL 36688. NIST,CARB,ROCKVILLE,MD 20850. 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 SEP 7 PY 1997 VL 214 BP 192 EP COMP PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ857 UT WOS:A1997XQ85701391 ER PT J AU Takahashi, H Antonucci, J Stansbury, J Wang, F AF Takahashi, H Antonucci, J Stansbury, J Wang, F TI Relationship between the tensile and flexural strength of composite resins. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 TOKYO MED & DENT UNIV,TOKYO 113,JAPAN. 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 SEP 7 PY 1997 VL 214 BP 198 EP POLY PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901127 ER PT J AU Miyazaki, K Endo, T Sanda, F Moriya, O Fukushima, T Antonucci, JM AF Miyazaki, K Endo, T Sanda, F Moriya, O Fukushima, T Antonucci, JM TI Synthesis and polymerization of acrylic monomers with pendant spiro ortho ester and cyclic carbonate groups. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 FUKUOKA DENT COLL,DEPT DENT MAT,FUKUOKA 8140,JAPAN. TOKYO INST TECHNOL,YOKOHAMA,KANAGAWA 227,JAPAN. NATL DEF ACAD,YOKOSUKA,KANAGAWA 2399,JAPAN. NATL INST STAND & TECHNOL,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 SEP 7 PY 1997 VL 214 BP 199 EP POLY PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901128 ER PT J AU Hu, XD Kumar, S Polk, MB VanderHart, DL AF Hu, XD Kumar, S Polk, MB VanderHart, DL TI Poly(benzobisthiazole) with tetramethylbiphenyl moiety in the main chain SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 GEORGIA INST TECHNOL,SCH TEXT & FIBER ENGN,ATLANTA,GA 30332. NATL INST STAND & TECHNOL,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 SEP 7 PY 1997 VL 214 BP 208 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901470 ER PT J AU Jackson, CL Chanzy, HD Booy, FP Tomalia, DA Amis, EJ AF Jackson, CL Chanzy, HD Booy, FP Tomalia, DA Amis, EJ TI Characterization of dendrimer molecules by staining and cryoelectron microscopy techniques. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. CNRS,CERMAV,GRENOBLE,FRANCE. NIH,BETHESDA,MD 20892. MICHIGAN MOL INST,MIDLAND,MI 48640. 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 SEP 7 PY 1997 VL 214 BP 259 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901521 ER PT J AU Valachovic, DE Bauer, BJ Amis, EJ Tomalia, DA AF Valachovic, DE Bauer, BJ Amis, EJ Tomalia, DA TI Dendrimer end group localization determined by counterion mirroring. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV SO CALIF,DEPT CHEM,LOS ANGELES,CA 90089. NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899. MICHIGAN MOL INST,MIDLAND,MI 48640. 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 SEP 7 PY 1997 VL 214 BP 263 EP PMSE PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85901525 ER PT J AU PetralliMallow, TP Plant, AL Hicks, JM AF PetralliMallow, TP Plant, AL Hicks, JM TI Studies of molecules at self-assembled surfaces via nonlinear optics. 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 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 SEP 7 PY 1997 VL 214 BP 297 EP PHYS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900811 ER PT J AU Parikh, AN Eberhardt, AS Swanson, BI Meuse, C Silin, V Plant, AL AF Parikh, AN Eberhardt, AS Swanson, BI Meuse, C Silin, V Plant, AL TI Effects of chain-matrix architecture on receptor-protein interactions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NIST,GAITHERSBURG,MD 20899. RI PARIKH, ATUL/D-2243-2014 OI PARIKH, ATUL/0000-0002-5927-4968 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 SEP 7 PY 1997 VL 214 BP 324 EP PHYS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900838 ER PT J AU Steel, AB AF Steel, AB TI Electrochemical characterization of DNA-containing monolayers. 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 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 SEP 7 PY 1997 VL 214 BP 325 EP PHYS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900839 ER PT J AU Levicky, R Herne, TM Steel, A Tarlov, MJ AF Levicky, R Herne, TM Steel, A Tarlov, MJ TI Surface-tethered single stranded DNA oligonucleotides - Structure and hybridization activity. 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 SEP 7 PY 1997 VL 214 BP 332 EP PHYS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900846 ER PT J AU Vanderah, DJ Meuse, CW Silin, V Plant, AL AF Vanderah, DJ Meuse, CW Silin, V Plant, AL TI Synthesis and characterization of self-assembled monolayers (SAMS) of alkylated 3,6,9,12,15,18-hexaoxathiols on gold (Au). 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 SEP 7 PY 1997 VL 214 BP 333 EP PHYS PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900847 ER PT J AU Kleiman, VD Arrivo, SM Heilweil, EJ AF Kleiman, VD Arrivo, SM Heilweil, EJ TI Control over a vibrational excitation process in solution: Vibrational up-pumping of W(CO)(6) with chirped IR pulses. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST,OPT TECHNOL DIV,GAITHERSBURG,MD 20899. UNIV CALIF LOS ANGELES,DEPT CHEM ENGN,LOS ANGELES,CA 90024. 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 SEP 7 PY 1997 VL 214 BP 410 EP PHYS PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900924 ER PT J AU Lovejoy, ER Hanson, DR Huey, LG AF Lovejoy, ER Hanson, DR Huey, LG TI Kinetics of the gas phase reactions of SO3 with H2O and NH3. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA,AERON LAB,BOULDER,CO 80303. 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 SEP 7 PY 1997 VL 214 BP 419 EP PHYS PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XQ859 UT WOS:A1997XQ85900933 ER PT J AU Goldfarb, L Schmoltner, AM Gilles, MK Burkholder, JB Ravishankara, AR AF Goldfarb, L Schmoltner, AM Gilles, MK Burkholder, JB Ravishankara, AR TI Photodissociation of ClONO2 .1. Atomic resonance fluorescence measurements of product quantum yields SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ABSORPTION CROSS-SECTIONS; CHLORINE NITRATE; WAVELENGTH RANGE; BALLOON-BORNE; PHOTOLYSIS; TEMPERATURE; KINETICS; HNO3; NM AB The quantum yields for the production of Cl, O, and ClO in the photolysis of ClONO2, measured by detecting Cl and O atoms by atomic resonance fluorescence, are reported. The resonance fluorescence signals were calibrated by generating known concentrations of Cl and O atoms from the photolysis of Cl-2, HCl, O-3, or N2O. The quantum yields for Ci in the 193.2, 222.0, 248.25, and 308.15 nm photolysis of ClONO2 were 0.53 +/- 0.10, 0.46 +/- 0.10, 0.41 +/- 0.13, and 0.64 +/- 0.20, respectively. The yields for O atoms at these wavelengths were, respectively, 0.37 +/- 0.08, 0.17 +/- 0.05, <0.10, and <0.05. The quoted uncertainties are 2 sigma precision of the measurements. ClO radical was converted to Cl via addition of NO and its signal compared to the Cl atom signal produced by photolysis of ClONO2. The obtained quantum yields for ClO were 0.29 +/- 0.20, 0.64 +/- 0.20, 0.39 +/- 0.19, and 0.37 +/- 0.19, at 193.2, 222.0, 248.25, and 308.15 nm, respectively. It appears that Cl + NO3 and ClO + NO2 are the major products in the photodissociation of ClONO2, except at 193 nm. The measured quantum yields were found to be independent of pressure (40-100 Ton) and bath gas (He and N-2). Our results are compared with those from previous measurements. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NOAA,AERON LAB,REAL2,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 36 TC 18 Z9 18 U1 0 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 SEP 4 PY 1997 VL 101 IS 36 BP 6658 EP 6666 DI 10.1021/jp970818f PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XV734 UT WOS:A1997XV73400037 ER PT J AU Yokelson, RJ Burkholder, JB Fox, RW Ravishankara, AR AF Yokelson, RJ Burkholder, JB Fox, RW Ravishankara, AR TI Photodissociation of ClONO2 .2. Time-resolved absorption studies of product quantum yields SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TEMPERATURE-DEPENDENCE; CHLORINE NITRATE; WAVELENGTH RANGE; CROSS-SECTIONS; PHOTOLYSIS; SPECTRUM; NO3; NM AB The quantum yield for NO3 production in the UV photolysis of ClONO2 was measured via transient 661.9 nm absorption of NO3 following pulsed laser photolysis and was found to be 0.93 +/- 0.24 at 352.5 nm, 0.67 +/- 0.09 at 308.15 nm, 0.60 +/- 0.09 at 248.25 nm, and 0.18 +/- 0.04 at 193 nm. The Cl atom quantum yield was measured by reacting Cl with ClONO2 to produce NO3 through the reaction Cl + ClONO2 --> Cl-2 + NO3 and was found to be 0.73 +/- 0.14 at 308.15 nm, 0.60 +/- 0.12 at 248.25 nm, and 0.45 +/- 0.08 at 193 nm. The estimated O atom yields were <0.4 at 248.25 nm and <0.9 at 193 nm. Quoted error limits are at the 95% confidence level and include estimated systematic errors. The results from this study are compared with those from previous studies. On the basis of this work and that of Goldfarb et al. (Goldfarb, L.; Schmoltner, A.-M.; Gilles, M. K.; Burkholder, J. B.; Ravishankara, A. R. J. Phys. Chem. 1997, 101, 6658.), it is concluded that Cl and NO3 are the major products in the photolysis of ClONO2 at wavelengths important in the stratosphere and that the total quantum yield for dissociation is close to 1. The implications of these findings to stratospheric chemistry are discussed. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NOAA,AERON LAB,REAL2,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RI Yokelson, Robert/C-9971-2011; Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 OI Yokelson, Robert/0000-0002-8415-6808; NR 23 TC 15 Z9 15 U1 0 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 SEP 4 PY 1997 VL 101 IS 36 BP 6667 EP 6678 DI 10.1021/jp9708198 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XV734 UT WOS:A1997XV73400038 ER PT J AU Boo, DW Ozaki, Y Andersen, LH Lineberger, WC AF Boo, DW Ozaki, Y Andersen, LH Lineberger, WC TI Femtosecond dynamics of linear Ag-3 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-STATE SPECTROSCOPY; IB METALS CU; PHOTOELECTRON-SPECTROSCOPY; SILVER CLUSTERS; SODIUM TRIMER; SPECTRA; PHOTODETACHMENT; IONS; AG3; AU AB A femtosecond negative ion-neutral-positive ion charge reversal apparatus has been developed, following the concept of Woste and Berry, to carry out spectroscopy of transient neutral species along the reaction coordinate. We report studies of the ultrafast dynamics of linear Ags produced by photodetachment of linear Ag-3(-). The background-free time-resolved multiphoton ionization spectra of Ag-3 taken at various wavelengths show a strong probe time and wavelength dependence, indicating important roles both of an intermediate state resonance and the ionization detection window in the time-resolved ionization signal. Based on these results, we speculate on the wavepacket dynamics along the coordinate of the linear-to-triangular rearrangement on the ground state potential energy surface. C1 JOSAI UNIV,DEPT CHEM,SAKADO,SAITAMA,JAPAN. UNIV AARHUS,INST PHYS & ASTRON,DK-8000 AARHUS C,DENMARK. UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. NR 41 TC 77 Z9 77 U1 3 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 SEP 4 PY 1997 VL 101 IS 36 BP 6688 EP 6696 DI 10.1021/jp9711353 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XV734 UT WOS:A1997XV73400040 ER PT J AU De Bievre, P Kaarls, R Peiser, HS Rasberry, SD Reed, WP AF De Bievre, P Kaarls, R Peiser, HS Rasberry, SD Reed, WP TI Protocols for traceability in chemical analysis Part II: Design and use SO ACCREDITATION AND QUALITY ASSURANCE LA English DT Review DE traceability; protocol analysis; reference material; uncertainty AB In continuing their attempt to bring general issues concerned with trustworthy chemical measurements to review and international discussion, the authors propose basic aims and requirements for protocols of chemical-measurement procedures with traceability to the SI or, where this is not possible, to units of internationally recognized measurement scales. Documents describing such protocols could be useful in science, technology, law, or trade. Concepts and definitions for protocols have been introduced in Part I of this contribution. Part II here deals with the development and application of protocols for intended in-laboratory, commercial, national, or international recognition. Protocols deal with measurement methods, instrumentation, and the estimation of uncertainties from all possible sources of measurement errors. Uncertainties define the quality of all links in a traceability chain starting from the value of a measurand in a sample, often through a certified value in a reference material, either to the SI, or - if this is not possible - to a value on a suitable, internationally agreed measurement scale. A protocol may concern itself with the complex interplay between uncertainties tolerances, and any limit values introduced by the set aims of specific measurements. C1 Commiss European Communities, Joint Res Ctr, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. Netherlands Measurements Inst, NL-2600 AR Delft, Netherlands. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP De Bievre, P (reprint author), Commiss European Communities, Joint Res Ctr, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. NR 15 TC 10 Z9 10 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0949-1775 J9 ACCREDIT QUAL ASSUR JI Accredit. Qual. Assur. PD SEP PY 1997 VL 2 IS 6 BP 270 EP 274 PG 5 WC Chemistry, Analytical; Instruments & Instrumentation SC Chemistry; Instruments & Instrumentation GA YX256 UT WOS:000072022000002 ER PT J AU Bergin, T Mahoney, MS Kay, AC Wirth, N Ritchie, DM Whitaker, WA Colmerauer, A Ichbiah, J Guidi, J Frankston, R Stewart, S Sammet, J Galler, B Steele, G Aditya, S Salomon, D Gabriel, RP Schorsch, T Conrad, P Crowl, L Mager, P Makrakis, S AF Bergin, T Mahoney, MS Kay, AC Wirth, N Ritchie, DM Whitaker, WA Colmerauer, A Ichbiah, J Guidi, J Frankston, R Stewart, S Sammet, J Galler, B Steele, G Aditya, S Salomon, D Gabriel, RP Schorsch, T Conrad, P Crowl, L Mager, P Makrakis, S TI HOPL II - Closing panel: The history of programming: Does our present past have a future? SO ACM SIGPLAN NOTICES LA English DT Editorial Material C1 APPLE COMP INC,CUPERTINO,CA 95014. PRINCETON UNIV,PRINCETON,NJ 08544. ETH ZURICH,ZURICH,SWITZERLAND. AT&T BELL LABS,NAPERVILLE,IL 60566. USAF,WASHINGTON,DC 20330. FAC SCI LUMINY,F-13288 MARSEILLE,FRANCE. SYRACUSE UNIV,SYRACUSE,NY 13244. JACKSON LAB,BAR HARBOR,ME 04609. NIST,GAITHERSBURG,MD 20899. UNIV LONDON KINGS COLL,LONDON WC2R 2LS,ENGLAND. UNIV MICHIGAN,ANN ARBOR,MI 48109. THINKING MACHINES CORP,BEDFORD,MA 01730. MIT,COMP SCI LAB,CAMBRIDGE,MA 02139. UNIV MANITOBA,WINNIPEG,MB R3T 2N2,CANADA. USAF ACAD,COLORADO SPRINGS,CO 80840. UNIV DELAWARE,NEWARK,DE 19716. OREGON STATE UNIV,CORVALLIS,OR 97331. PERCEPT TECHNOL CORP,CANTON,MA 02021. RP Bergin, T (reprint author), AMERICAN UNIV,WASHINGTON,DC 20016, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0362-1340 J9 ACM SIGPLAN NOTICES JI ACM Sigplan Not. PD SEP PY 1997 VL 32 IS 9 BP 15 EP 37 DI 10.1145/270507.270509 PG 23 WC Computer Science, Software Engineering SC Computer Science GA XZ385 UT WOS:A1997XZ38500001 ER PT J AU Levine, LE Thomson, R AF Levine, LE Thomson, R TI X-ray scattering by dislocations in crystals. General theory and application to screw dislocations SO ACTA CRYSTALLOGRAPHICA SECTION A LA English DT Article ID PLASTICALLY DEFORMED-CRYSTALS; LINE AB Line profiling of X-ray Bragg peaks has great potential for extracting meaningful physical parameters from work-hardened single-crystal samples; these include both dislocation densities and ordering lengths. However, a detailed reading of the existing literature uncovered shortcomings in the required theoretical understanding of scattering from dislocations. A mathematically rigorous theoretical framework is presented for understanding dislocation scattering; the procedure is based upon first principles of kinematic scattering and basic laws of probability theory. These results are then applied to the specific case of parallel screw dislocations. As expected from experimental measurements, the solution to this problem is neither Gaussian nor Lorentzian but is 'intermediate' between these distributions. Detailed computer simulations of the scattering are carried out and compared to the theoretical predictions. The predictions match the computer simulations with no adjustable parameters. Comparisons are also made to the work of previous authors. C1 NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899. RP Levine, LE (reprint author), WASHINGTON STATE UNIV,SCH MECH & MAT ENGN,PULLMAN,WA 99164, USA. NR 16 TC 32 Z9 32 U1 3 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7673 J9 ACTA CRYSTALLOGR A JI Acta Crystallogr. Sect. A PD SEP 1 PY 1997 VL 53 BP 590 EP 602 DI 10.1107/S0108767397005989 PN 5 PG 13 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA YB344 UT WOS:A1997YB34400008 ER PT J AU Levin, I Bendersky, LA Brandon, DG Ruhle, M AF Levin, I Bendersky, LA Brandon, DG Ruhle, M TI Cubic to monoclinic phase transformations in alumina SO ACTA MATERIALIA LA English DT Article AB Cubic to monoclinic phase transformations in alumina were studied by high-resolution electron microscopy of anodic films annealed at 1200 degrees C. In addition to the known monoclinic theta-Al2O3 structure a new metastable alumina polymorph was identified also with apparent monoclinic symmetry. This new phase appears to evolve from gamma-alumina by cation ordering. The stoichiometric structure of this polymorph is consistent with the C2/m space group and unit cell containing 40 ions (8Al(2)O(3)). Reasonably good fit between experimental and computer-simulated lattice images was obtained for the suggested structural model. The transformations of gamma-Al2O3 to both monoclinic alumina structures were assumed to be non-reconstructive and the possible transformation paths were analyzed in terms of symmetry group/subgroup relationships. (C) 1997 Acta Metallurgica Inc. C1 NIST,DIV MET,GAITHERSBURG,MD 20899. MAX PLANCK INST MET RES,INST WERKSTOFFWISSENSCH,D-70174 STUTTGART,GERMANY. RP Levin, I (reprint author), TECHNION ISRAEL INST TECHNOL,FAC MAT ENGN,IL-32000 HAIFA,ISRAEL. RI Levin, Igor/F-8588-2010 NR 14 TC 51 Z9 51 U1 1 U2 25 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD SEP PY 1997 VL 45 IS 9 BP 3659 EP 3669 DI 10.1016/S1359-6454(97)00040-2 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA XT971 UT WOS:A1997XT97100015 ER PT J AU Middlebrook, AM Thomson, DS Murphy, DM AF Middlebrook, AM Thomson, DS Murphy, DM TI On the purity of laboratory-generated sulfuric acid droplets and ambient particles studied by laser mass spectrometry SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID STRATOSPHERIC AEROSOLS; NO2 AB Particle analysis by laser mass spectrometry (PALMS) was used to examine sulfuric acid particles representative of stratospheric sulfate aerosols (SSAs) and ambient tropospheric aerosols. Sulfuric acid particles were generated in the laboratory by condensing sulfuric acid vapors in a flow stream of particle-free dry air or nitrogen. The purest particles were produced using filtered, high-purity nitrogen in a clean glass and stainless steel system. In contrast, generation techniques using filtered compressed air, Tygon tubing, or Viton o-rings resulted in detectable organic impurities in the positive ion spectra of sulfuric acid droplets. With the PALMS instrument, the lower limit of our detection of organics is at most 0.02 wt% alpha-tocopherol in sulfuric acid, which in terms of surface coverage corresponds to less than one monolayer on a 0.2-mu m-diameter particle. When we eventually deploy the PALMS instrument in the upper troposphere and lower stratosphere, we should be able to detect the presence of very small amounts of organic compounds in SSAs. In the atmosphere, residence times are long and tropospheric concentrations of reactive gas-phase organic compounds are high, implying that ambient sulfuric acid particles are unlikely to be pure. Other experiments using internally mixed tridecane/sulfuric acid particles confirm that ambient particles from Boulder, CO and Idaho Hill, CO contain internal mixtures of oxidized organic compounds and sulfate. (C) 1997 American Association for Aerosol Research. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Middlebrook, AM (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Middlebrook, Ann/E-4831-2011; Murphy, Daniel/J-4357-2012 OI Middlebrook, Ann/0000-0002-2984-6304; Murphy, Daniel/0000-0002-8091-7235 NR 23 TC 40 Z9 40 U1 1 U2 3 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 SEP PY 1997 VL 27 IS 3 BP 293 EP 307 DI 10.1080/02786829708965475 PG 15 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XR300 UT WOS:A1997XR30000002 ER PT J AU Chase, SC AF Chase, SC TI Modelling spatial reasoning systems with shape algebras and formal logic SO AI EDAM-ARTIFICIAL INTELLIGENCE FOR ENGINEERING DESIGN ANALYSIS AND MANUFACTURING LA English DT Article DE shape algebras; shape grammars; feature emergence; feature recognition; formal logic ID GENERATION; LANGUAGE; GRAMMAR; DESIGNS; IMPLEMENTATION AB The combination of the paradigms of shape algebras and predicate logic representations, used in a new method for describing designs, is presented. First-order predicate logic provides a natural, intuitive way of representing shapes and spatial relations in the development of complete computer systems for reasoning about designs. Shape algebraic formalisms have advantages over more traditional representations of geometric objects. Here we illustrate the definition of a large set of high-level design relations from a small set of simple structures and spatial relations, with examples from the domains of geographic information systems and architecture. C1 NATL INST STAND & TECHNOL, MFG SYST INTEGRAT DIV, GAITHERSBURG, MD 20899 USA. NR 41 TC 1 Z9 1 U1 1 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0890-0604 EI 1469-1760 J9 AI EDAM JI AI EDAM-Artif. Intell. Eng. Des. Anal. Manuf. PD SEP PY 1997 VL 11 IS 4 BP 273 EP 285 PG 13 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary; Engineering, Manufacturing SC Computer Science; Engineering GA XZ311 UT WOS:A1997XZ31100004 ER PT J AU Forbes, JM Hagan, ME Zhang, X Hamilton, K AF Forbes, JM Hagan, ME Zhang, X Hamilton, K TI Upper atmosphere tidal oscillations due to latent heat release in the tropical troposphere SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article; Proceedings Paper CT 2nd Workshop on Wind Measurements in the Middle Atmosphere CY MAY 13-16, 1996 CL UNIV TORONTO, TORONTO, CANADA SP York Univ, CSA HO UNIV TORONTO ID LOWER THERMOSPHERE; DIURNAL CYCLE; PACIFIC; WAVE AB Latent heat release associated with tropical deep convective activity is investigated as a source for migrating (sun-synchronous) diurnal and semidiurnal tidal oscillations in the 80-150-km height region. Satellite-based cloud brightness temperature measurements made between 1988 and 1994 and averaged into 3-h bins are used to determine the annual-and longitude-average local-time distribution of rainfall rate, and hence latent heating, between +/-40 degrees latitude. Regional average rainfall rates are shown to be in good agreement with climatological values derived from surface rain gauge data. A global linearized wave model is used to estimate the corresponding atmospheric perturbations in the mesosphere/lower thermosphere (80-150 km) resulting from upward-propagating tidal components excited by the latent heating. The annual-average migrating diurnal and semidiurnal components achieve velocity and temperature amplitudes of order 10-20 m s(-1) and 5-10 K, respectively, which represent substantial contributions to the dynamics of the region. The latent heat forcing also shifts the phase (local solar time of maximum! of the semidiurnal surface pressure oscillation from 0912. to 0936 h, much closer to the observed value of 0944 h. C1 NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,BOULDER,CO 80307. PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,PRINCETON,NJ 08544. RP Forbes, JM (reprint author), UNIV COLORADO,DEPT AEROSP ENGN SCI,BOULDER,CO 80309, USA. RI Hagan, Maura/C-7200-2008; OI Hagan, Maura/0000-0002-8866-7429; FORBES, JEFFREY/0000-0001-6937-0796 NR 20 TC 59 Z9 59 U1 0 U2 4 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 SEP PY 1997 VL 15 IS 9 BP 1165 EP 1175 DI 10.1007/s00585-997-1165-0 PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA YF704 UT WOS:A1997YF70400008 ER PT J AU Rochford, KB Rose, AH Williams, PA Wang, CM Clarke, IG Hale, PD Day, GW AF Rochford, KB Rose, AH Williams, PA Wang, CM Clarke, IG Hale, PD Day, GW TI Design and performance of a stable linear retarder SO APPLIED OPTICS LA English DT Article DE polarization; retarder; retardance measurement; standards; wave plate ID POLARIZATION AB The National institute of Standards and Technology (NIST) has developed a nominally quarter-wave linear retarder for wavelengths near 1.3 mu m that is stable within +/-0.1 degrees retardance over a range of wavelength, input angle, temperature, and environmental variations. The device consists of two concatenated Fresnel rhombs made from a low stress-optic-coefficient glass that minimizes the residual birefiringence from machining and packaging. Device machining, assembly, and antireflection coating tolerances are discussed, and the theoretical performance is compared with measurements, Humidity can modify retardance of the total-internal-reflection surfaces; we discuss packaging that mitigatas this effect and provides an estimated IO-Fear lifetime for the device. Several measurement methods were intercompared to ensure that the device retardance can be measured with an uncertainty less than 0.1 degrees. Similar retarders will be certified by NIST and made available as Standard Reference Materials. C1 NATL INST STAND & TECHNOL,STAT ENGN DIV,BOULDER,CO 80303. RP Rochford, KB (reprint author), NATL INST STAND & TECHNOL,DIV OPTOELECT,325 BROADWAY,BOULDER,CO 80303, USA. RI Hale, Paul/B-1737-2013 NR 26 TC 20 Z9 20 U1 0 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 SEP 1 PY 1997 VL 36 IS 25 BP 6458 EP 6465 DI 10.1364/AO.36.006458 PG 8 WC Optics SC Optics GA XT925 UT WOS:A1997XT92500041 PM 18259504 ER PT J AU Williams, PA Rose, AH Wang, CM AF Williams, PA Rose, AH Wang, CM TI Rotating-polarizer polarimeter for accurate retardance measurement SO APPLIED OPTICS LA English DT Article AB We demonstrate an automated polarimeter based on a rotating polarizer for the measurement of linear retardance independent of laser power and detector gain. The retardance is found when a curve is fitted to a unique normalization of the intensity response of the polarimeter or;er a range of input polarizer orientations. The performance of this polarimeter is optimal for measurements of quarter-wave retardance and minimal for half wave retardance. Uncertainties are demonstrated by measurements an six stable double Fresnel rhombs of nominal quarter-wave retardance, yielding expanded uncertainties between 0.031 degrees and 0.067 degrees. The accuracy has also been verified by blind comparisons with interferometric and modified null retardance measurement techniques. RP Williams, PA (reprint author), NATL INST STAND & TECHNOL, DIV OPTOELECT, MS 815-02, 826 BROADWAY, BOULDER, CO 80303 USA. NR 22 TC 47 Z9 52 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD SEP 1 PY 1997 VL 36 IS 25 BP 6466 EP 6472 DI 10.1364/AO.36.006466 PG 7 WC Optics SC Optics GA XT925 UT WOS:A1997XT92500042 PM 18259505 ER PT J AU Rochford, KB Wang, CM AF Rochford, KB Wang, CM TI Accurate interferometric retardance measurements SO APPLIED OPTICS LA English DT Article DE Fresnel rhomb; interferometry; polarization; retardance measurement AB A two-polarization Michelson interferometer with a low-retardance beam splitter and digital signal processing is used to measure the retardance of optical devices. Error analysis of the improved optical system and data processing shows that the measurement has an uncertainty of 0.039 degrees for measurements of nominally 90 degrees retarders. Retardance variations arising from coherent reflections in the retarder used for intercomparison add an uncertainty of from 0.005 degrees to 0.03 degrees, increasing the combined measurement uncertainty to as much as 0.049 degrees. C1 NATL INST STAND & TECHNOL,STAT ENGN DIV,BOULDER,CO 80303. RP Rochford, KB (reprint author), NATL INST STAND & TECHNOL,DIV OPTOELECT,825 BROADWAY,BOULDER,CO 80303, USA. NR 14 TC 21 Z9 21 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD SEP 1 PY 1997 VL 36 IS 25 BP 6473 EP 6479 DI 10.1364/AO.36.006473 PG 7 WC Optics SC Optics GA XT925 UT WOS:A1997XT92500043 PM 18259506 ER PT J AU Miyano, KE Woicik, JC Devi, PS Gafney, HD AF Miyano, KE Woicik, JC Devi, PS Gafney, HD TI Cr K edge x-ray absorption study of Cr dopants in Mg2SiO4 and Ca2GeO4 SO APPLIED PHYSICS LETTERS LA English DT Article ID CHROMIUM-DOPED FORSTERITE; LASER ACTION; SPECTRA; ION AB X-ray absorption above the Cr K edge has been used to study two Cr-doped olivine-structure materials. For Mg2SiO4, the extended fine structure shows that Cr resides in octahedral and tetrahedral sites with Cr-O distances of 1.98+/-0.03 and 1.68+/- 0.03 Angstrom, while the near edge structure indicates that Cr is in 3(+) and 4(+) oxidation states. For Ca2GeO4, site-size constraints limit Cr to the tetrahedral site with a Cr-O distance of 1.745+/-0.02 Angstrom, and this Cr is only in the 4(+) oxidation state. This study illustrates the utility of x-ray absorption for probing and relating the oxidation states and sites of constituent elements. In this specific case of Cr in olivine hosts, such understanding is critical to the development of these materials as tunable infrared solid-state lasers: Cr in the 4(+) state provides the desired emission centered near 1.3 mu m. (C) 1997 American Institute of Physics. C1 NIST,GAITHERSBURG,MD 20899. CUNY QUEENS COLL,DEPT CHEM & BIOCHEM,FLUSHING,NY 11367. RP Miyano, KE (reprint author), CUNY BROOKLYN COLL,DEPT PHYS,BROOKLYN,NY 11210, USA. NR 16 TC 14 Z9 14 U1 0 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 SEP 1 PY 1997 VL 71 IS 9 BP 1168 EP 1170 DI 10.1063/1.119615 PG 3 WC Physics, Applied SC Physics GA XU062 UT WOS:A1997XU06200011 ER PT J AU Barnston, AG Chelliah, M Goldenberg, SB AF Barnston, AG Chelliah, M Goldenberg, SB TI Documentation of a highly ENSO-related SST region in the equatorial Pacific SO ATMOSPHERE-OCEAN LA English DT Article ID SEA-SURFACE TEMPERATURE; CANONICAL CORRELATION-ANALYSIS; EL-NINO; SOUTHERN OSCILLATION; NORTHERN-HEMISPHERE; PREDICTION; MODEL; PREDICTABILITY; VARIABILITY; CLIMATE AB A new ENSO SST index is documented that is strongly correlated to the core ENSO phenomenon. The SST anomaly in much of the east-central and eastern tropical Pacific is closely related to ENSO. However the anomaly from approximately the centre of the eastern half of the equatorial Pacific westward to near the date line is suggested to be most strongly ENSO-related when darn spanning the most recent several decades are used. This is the case both with respect to (1) strength of association with other oceanic/atmospheric ENSO-related anomalies (both simultaneously and as a time-delayed predictand), and (2) impact on remote worldwide climate anomalies. This observational insight was lacking in the early 1980s when the four ''Nino'' regions were developed. While a firmer dynamical foundation for this regional preference still needs to be established the region straddling Nino 3 and Nino 4 may be regarded as an appropriate general SST index of the ENSO state by researchers, diagnosticians and forecasters. A dataset of this index, called ''Nino 3.4'' (5 degrees N-5 degrees S, 120-170 degrees W), is maintained an the Internet, shown in the Climate Diagnostics Bulletin, and provided in the Appendix of this note. C1 NOAA, ERL, AOML, HURRICANE RES DIV, CORAL GABLES, FL 33146 USA. RP Barnston, AG (reprint author), NOAA, NWS, NCEP, CLIMATE PREDICT CTR, SILVER SPRING, MD 20910 USA. RI Goldenberg, Stanley/C-5965-2014 OI Goldenberg, Stanley/0000-0001-6730-5819 NR 45 TC 115 Z9 118 U1 5 U2 13 PU CANADIAN METEOROLOGICAL OCEANOGRAPHIC SOC PI OTTAWA PA 150 LOUIS PASTEUR PVT., STE 112, MCDONALD BUILDING, OTTAWA ON K1N 6N5, CANADA SN 0705-5900 J9 ATMOS OCEAN JI Atmos.-Ocean PD SEP PY 1997 VL 35 IS 3 BP 367 EP 383 PG 17 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA YC396 UT WOS:A1997YC39600005 ER PT J AU Planas, JV Goetz, FW Swanson, P AF Planas, JV Goetz, FW Swanson, P TI Stimulation of brook trout ovarian steroidogenesis by gonadotropins I and II is mediated by the cyclic adenosine 3',5'-monophosphate protein kinase A pathway SO BIOLOGY OF REPRODUCTION LA English DT Article ID LUTEINIZING-HORMONE RECEPTOR; SALMON ONCORHYNCHUS-RHODURUS; RAT GRANULOSA-CELLS; STEROID-PRODUCTION; GTH-II; COHO SALMON; ADENYLYL-CYCLASE; PHORBOL ESTER; REPRODUCTIVE-CYCLE; OOCYTE MATURATION AB In teleosts, ovarian steroidogenesis is under the control of two gonadotropic hormones, GTH I and GTH II, that are structurally and functionally homologous to FSH and LH. The intracellular mechanisms by which GTH I and GTH II stimulate steroidogenesis in the teleost ovary are not well understood. The purpose of this study was to investigate the involvement of the cAMP/protein kinase A (PKA) and protein kinase C (PKC)/Ca2+ signaling pathways in the steroidogenic actions of GTH I and GTH II in the ovary of the brook trout (Salvelinus fontinalis). The cAMP/PKA pathway mediated the actions of GTH I before germinal vesicle breakdown (preGVBD) and GTH II after GVBD and before ovulation (preOV). Experimental increases in intracellular cAMP concentration mimicked the steroidogenic effects of GTH I and GTH II, and an antagonistic analog of cAMP partially blocked them. In addition, GTH I and GTH II stimulated the production of cAMP in preGVBD and preOV follicles, respectively. Activation of the PKC/Ca2+ pathway by a phorbol ester or a Ca2+ ionophore blocked the GTH I-and GTH II-induced steroid production, whereas inhibition of PKC by specific inhibitors potentiated the effects of GTH I. These results suggest that the cAMP/PKA signaling pathway mediates the stimulatory effects of GTH I and GTH II on steroidogenesis, and they also suggest the additional involvement of the PKC/Ca2+ signaling pathway in modulating the actions of gonadotropins in brook trout ovarian follicles. C1 UNIV WASHINGTON,SCH FISHERIES,SEATTLE,WA 98195. UNIV NOTRE DAME,DEPT BIOL SCI,NOTRE DAME,IN 46556. NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,SEATTLE,WA 98112. NR 56 TC 36 Z9 37 U1 0 U2 1 PU SOC STUDY REPRODUCTION PI MADISON PA 1603 MONROE ST, MADISON, WI 53711-2021 SN 0006-3363 J9 BIOL REPROD JI Biol. Reprod. PD SEP PY 1997 VL 57 IS 3 BP 647 EP 654 DI 10.1095/biolreprod57.3.647 PG 8 WC Reproductive Biology SC Reproductive Biology GA XR469 UT WOS:A1997XR46900023 PM 9283003 ER PT J AU Petrash, S LiebmannVinson, A Foster, MD Lander, LM Brittain, WJ Majkrzak, CF AF Petrash, S LiebmannVinson, A Foster, MD Lander, LM Brittain, WJ Majkrzak, CF TI Neutron and X-ray reflectivity studies of human serum albumin adsorption onto functionalized surfaces of self-assembled monolayers SO BIOTECHNOLOGY PROGRESS LA English DT Article ID SPECULAR REFLECTION; ORGANIC MONOLAYERS; SILICON; ALKYLSILOXANES; PROTEINS AB Neutron and X-ray reflectivity (NR and XR) have been widely used for the investigation of the structure of thin organic films. Here we demonstrate how these sensitive techniques may be applied to the study of protein adsorption to well-characterized self-assembled monolayers (SAMs) with different chemical functionalities. NR can be used for in situ study, while XR provides complementary information on the initial surfaces and dried layers measured in air after protein has been adsorbed. In situ measurements of adsorption of human serum albumin onto a hydrophilic NH2-terminated monolayer clearly show the presence of a thin layer of adsorbed protein next to the SAM. Adsorption of albumin onto a hydrophobic, deuterated, CD3-terminated SAM causes even bigger changes in the NR. Upon replacing the protein solution with protein-free buffer solution, the reflectivities from both kinds of monolayers do not change, demonstrating that the albumin adsorption is irreversible after several hours of contact with the protein solution. X-ray reflectivity measurements of dried substrates performed ex situ in air provide a lower bound estimate of the amount of protein which must be at the interface in. situ. This combination of techniques provides a uniquely sensitive approach for studying changes that occur upon protein adsorption at an interface. C1 UNIV AKRON,INST POLYMER SCI,AKRON,OH 44325. NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. NR 20 TC 24 Z9 24 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 8756-7938 J9 BIOTECHNOL PROGR JI Biotechnol. Prog. PD SEP-OCT PY 1997 VL 13 IS 5 BP 635 EP 639 DI 10.1021/bp970068r PG 5 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA YA276 UT WOS:A1997YA27600021 PM 9336983 ER PT J AU Mundy, BC Moser, HG AF Mundy, BC Moser, HG TI Development of early stages of pelagic armorhead Pseudopentaceros wheeleri with notes on juvenile Ps-richardsoni and larval Histiopterus typus (Pisces, Percoidei, Pentacerotidae) SO BULLETIN OF MARINE SCIENCE LA English DT Article ID NORTH PACIFIC-OCEAN; GULF-OF-MEXICO; PERCOMORPH PHYLOGENY; FISHES; PERCIFORMES; MORPHOLOGY; POPULATION; TELEOSTEI; SEAMOUNTS; ATLANTIC AB Two larvae (4.2 and 7.2 mm notochord length (NL)) and 28 juveniles (8.3-15.3 mm standard length (SL)) of the pelagic armorhead Pseudopentaceros wheeleri, are described from surface tows taken near seamounts in the central North Pacific Ocean (29.5-30.5 degrees N, 178-180 degrees E) during February 1985. Diagnostic features of the larvae include dark pigment on all but the posterior 9-20% of the body, a thick, long intestine (preanal length 76.4-76.9% NL), a supraoccipital crest, spiny supraorbital ridges, and preopercular spines. Juveniles are darkly pigmented over the head and body, with a blotched pattern on specimens >11 mm SL. In juveniles, additional large spines are present on the lacrimals, posttemporals, supracleithra, and cleithral lobes. A 7.4-mm SL Histiopterus typus larva from western Australia has similar head spines but strikingly elongated dorsal-and pelvic-fin elements, more evenly distributed pigment, a larger head, and a more compressed body, compared to Ps. wheeleri. Juvenile Ps. wheeleri can be differentiated from juveniles of the other North Pacific pentacerotids, Pentaceros japonicus and Evistias acutirostris, by numbers of fin rays and from the very similar Southern Hemisphere Ps. richardsoni by vertebral count, interpelvic width, and the absence of anterior spines on the supraoccipital crest. All known armorhead juveniles share a distinctive pattern of cranial spines that includes spines on the lacrimals, large spines in laterally projecting supraorbital ridges, and an enlarged, serrated supraoccipital crest, in addition to the spines on the preopercles, opercles, posttemporals, supracleithra, and pterotics found in many percomorph larvae. Pelagic young of Ps. wheeleri were collected only in neuston tows in winter. The neustonic distribution of small pelagic armorhead may contribute to their advection from seamount spawning sites. C1 Natl Marine Fisheries Serv, Honolulu Lab, SW Fisheries Sci Ctr, NOAA, Honolulu, HI 96822 USA. Natl Marine Fisheries Serv, La Jolla Lab, SW Fisheries Sci Ctr, NOAA, La Jolla, CA 92038 USA. RP Mundy, BC (reprint author), Natl Marine Fisheries Serv, Honolulu Lab, SW Fisheries Sci Ctr, NOAA, 2570 Dole St, Honolulu, HI 96822 USA. NR 52 TC 9 Z9 9 U1 0 U2 0 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD SEP PY 1997 VL 61 IS 2 BP 241 EP 269 PG 29 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA YZ063 UT WOS:000072216600004 ER PT J AU Crabtree, RE Cyr, EC Chaverri, DC McLarney, WO Dean, JM AF Crabtree, RE Cyr, EC Chaverri, DC McLarney, WO Dean, JM TI Reproduction of tarpon, Megalops atlanticus, from Florida and Costa Rican waters and notes on their age and growth SO BULLETIN OF MARINE SCIENCE LA English DT Article ID LARVAE; PISCES; MEXICO; GULF AB We examined 1,469 tarpon ranging 102-2,045 mm fork length (FL) that were collected in South Florida waters and 217 tarpon ranging 880-1,860 mm FL that were collected in Costa Rican waters from 1989 to 1994. Among the Florida tarpon, gonads of 737 fish were examined histologically, and gonadosomatic indices were calculated for 409 tarpon. Among Costa Rican tarpon, gonads of 202 tarpon were examined histologically, and gonadosomatic indices were calculated for 178 tarpon. Florida fish were significantly Larger than those from Costa Rica, and sexually mature females were significantly larger than sexually mature males in both areas. All Florida males were sexually mature by 1,175 mm FL, and only one smaller male (901 mm) was mature. The smallest sexually mature Florida female was 1,285 mm FL, and all larger females except one were sexually mature. Only one Florida tarpon, a 7-yr-old female, younger than 10 yrs was sexually mature; all tarpon older than 10 yrs were sexually mature. In Costa Rica, only one immature female (880 mm FL) was examined; all other females (1,126-1,860 mm FL) were sexually mature. All Costa Rican males examined (880-1,550 mm FL) were sexually mature. Florida tarpon spawned during April-July and by August, most females were spent or recovering. Spawning in Costa Rican waters was not seasonal, and reproductively active females were caught during all months. Fecundity estimates for Florida tarpon ranged 4.5-20.7 million oocytes and had a significant positive relationship with fish weight. Otoliths of tarpon from Costa Rican waters were difficult to read. We examined thin-sectioned otoliths (sagittae) from 194 Costa Rican tarpon but could estimate ages for only 87 fish (45%). Costa Rican tarpon are long-lived and reach a maximum age of at least 48 yrs. Most (74%) tarpon caught in Costa Rica that we aged were 15 to 30 yrs old. C1 Florida Marine Res Inst, Dept Environm Protect, St Petersburg, FL 33701 USA. Natl Marine Fisheries Serv, Off Protected Resources, Silver Spring, MD 20910 USA. Asociac ANAI, San Jose, Costa Rica. ANAI Inc, Franklin, NC 28734 USA. Univ S Carolina, Inst Publ Affairs, Columbia, SC 29208 USA. RP Crabtree, RE (reprint author), Florida Marine Res Inst, Dept Environm Protect, 100 8th Ave SE, St Petersburg, FL 33701 USA. NR 14 TC 19 Z9 26 U1 2 U2 18 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD SEP PY 1997 VL 61 IS 2 BP 271 EP 285 PG 15 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA YZ063 UT WOS:000072216600005 ER PT J AU Joly, A Jorgensen, D Shapiro, MA Thorpe, A Bessemoulin, P Browning, KA Cammas, JP Chalon, JP Clough, SA Emanuel, KA Eymard, L Gall, R Hildebrand, PH Langland, RH Lemaitre, Y Lynch, P Moore, JA Persson, POG Snyder, C Wakimoto, RM AF Joly, A Jorgensen, D Shapiro, MA Thorpe, A Bessemoulin, P Browning, KA Cammas, JP Chalon, JP Clough, SA Emanuel, KA Eymard, L Gall, R Hildebrand, PH Langland, RH Lemaitre, Y Lynch, P Moore, JA Persson, POG Snyder, C Wakimoto, RM TI The Fronts and Atlantic Storm-Track Experiment (FASTEX): Scientific objectives and experimental design SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID MOIST DEFORMATION FRONTOGENESIS; POTENTIAL VORTICITY ANOMALIES; BAROCLINIC WAVES; FREQUENCY VARIABILITY; EXPLOSIVE CYCLONES; OPTIMAL EXCITATION; HEAT FLUXES; MESOSCALE; STABILITY; CYCLOGENESIS AB The Fronts and Atlantic Storm-Track Experiment (FASTEX) will address the life cycle of cyclones evolving over the North Atlantic Ocean in January and February 1997. The objectives of FASTEX are to improve the forecasts of end-of-storm-track cyclogenesis (primarily in the eastern Atlantic but with applicability to the Pacific) in the range 24 to 72 h, to enable the testing of theoretical ideas on cyclone formation and development, and to document the vertical and the mesoscale structure of cloud systems in mature cyclones and their relation to the dynamics. The observing system includes ships that will remain in the vicinity of the main baroclinic zone in the central Atlantic Ocean, jet aircraft that will fly and drop sondes off the east coast of North America or over the central Atlantic Ocean, turboprop aircraft that will survey mature cyclones off Ireland with dropsondes, and airborne Doppler radars, including ASTRAIA/ELDORA. Radiosounding frequency around the North Atlantic basin will be increased, as well as the number of drifting buoys. These facilities will be activated during multiple-day intensive observing periods in order to observe the same meteorological systems at several stages of their life cycle. A central archive will be developed in quasi-real time in Toulouse, France, thus allowing data to be made widely available to the scientific community. C1 NOAA,ERL,NATL SEVERE STORMS LAB,BOULDER,CO 80303. NOAA,ERL,ENVIRONM TECHNOL LAB,BOULDER,CO 80303. UNIV READING,JOINT CTR MESOSCALE METEOROL,READING RG6 2AH,BERKS,ENGLAND. LAB AEROL,TOULOUSE,FRANCE. UNITED KINGDOM METEOROL OFF,BRACKNELL,BERKS,ENGLAND. MIT,CAMBRIDGE,MA 02139. CTR ETUD ENVIRONM TERR & PLANETAIRES,VELIZY VILLACOUBL,FRANCE. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. USN,RES LAB,MONTEREY,CA. MET EIREANN,DUBLIN,IRELAND. UNIV CORP ATMOSPHER RES,BOULDER,CO. UNIV CALIF LOS ANGELES,CIRES,LOS ANGELES,CA. RP Joly, A (reprint author), METEO FRANCE,CNRM,GMME,42 AV G CORIOLIS,F-31057 TOULOUSE,FRANCE. RI Y, wang/A-8866-2010 NR 66 TC 129 Z9 137 U1 0 U2 6 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 SEP PY 1997 VL 78 IS 9 BP 1917 EP 1940 DI 10.1175/1520-0477(1997)078<1917:TFAAST>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YA066 UT WOS:A1997YA06600004 ER PT J AU Bond, NA Mass, CF Smull, BF Houze, RA Yang, MJ Colle, BA Braun, SA Shapiro, MA Colman, BR Neiman, PJ Overland, JE Neff, WD Doyle, JD AF Bond, NA Mass, CF Smull, BF Houze, RA Yang, MJ Colle, BA Braun, SA Shapiro, MA Colman, BR Neiman, PJ Overland, JE Neff, WD Doyle, JD TI The Coastal Observation and Simulation with Topography (COAST) experiment SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID EXTRATROPICAL MARINE CYCLONE; LIFE-CYCLE; MESOSCALE; OROGRAPHY; MOUNTAINS; RAINBANDS; DYNAMICS; BOUNDARY; BARRIER; FRONTS AB The Coastal Observation and Simulation with Topography (COAST) program has examined the interaction of both steady-state and transient cool-season synoptic features, such as fronts and cyclones, with the coastal terrain of western North America. Its objectives include better understanding and forecasting of landfalling weather systems and, in particular, the modification and creation of mesoscale structures by coastal orography. In addition, COAST has placed considerable emphasis on the evaluation of mesoscale models in coastal terrain. These goals have been addressed through case studies of storm and frontal landfall along the Pacific Northwest coast using special field observations from a National Oceanic and Atmospheric Administration WP-3D research aircraft and simulations from high-resolution numerical models. The field work was conducted during December 1993 and December 1995. Active weather conditions encompassing a variety of synoptic situations were sampled. This article presents an overview of the program as well as highlights from a sample of completed and ongoing case studies. C1 UNIV WASHINGTON, JOINT INST STUDY ATMOSPHERE & OCEANS, SEATTLE, WA 98195 USA. UNIV WASHINGTON, DEPT ATMOSPHER SCI, SEATTLE, WA 98195 USA. NOAA, NATL SEVERE STORMS LAB, NORMAN, OK 73069 USA. CENT WEATHER BUR, TAIPEI, TAIWAN. NCAR, BOULDER, CO USA. NOAA, ETL, BOULDER, CO USA. NATL WEATHER SERV, SEATTLE, WA USA. USN, RES LAB, MONTEREY, CA USA. RP NOAA, PACIFIC MARINE ENVIRONM LAB, 7600 SAND POINT WAY NE, SEATTLE, WA 98115 USA. RI Yang, Ming-Jen/F-4628-2012; Neff, William/E-2725-2010 OI Yang, Ming-Jen/0000-0001-6654-2791; Neff, William/0000-0003-4047-7076 NR 35 TC 38 Z9 39 U1 0 U2 1 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 SEP PY 1997 VL 78 IS 9 BP 1941 EP 1955 DI 10.1175/1520-0477(1997)078<1941:TCOASW>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YA066 UT WOS:A1997YA06600005 ER PT J AU Legeckis, R Zhu, T AF Legeckis, R Zhu, T TI Sea surface temperatures from the GOES-8 geostationary satellite SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB The introduction of the 10-bit, five-band, multispectral visible and thermal infrared scanner on the National Oceanic and Atmospheric Administration's GOES-8 satellite in 1994 offers an opportunity to estimate sea surface temperatures from a geostationary satellite. The advantage of the Geostationary Operational Environmental Satellite (GOES) over the traditional Advanced Very High Resolution Radiometer is the 30-min interval between images, which can increase the daily quantity of cloud-free ocean observations. Linear regression coefficients are estimated for GOES-8 by using the sea surface temperatures derived from the NOAA-14 polar-orbiting satellite as the dependent variable and the GOES infrared split window channels and the satellite zenith angle as independent variables. The standard error between the polar and geostationary sea surface temperature is 0.35 degrees C. Since the polar satellite sea surface temperature is estimated within 0.5 degrees C relative to drifting buoy near-surface measurements, this implies that the GOES-8 infrared scanner can be used to estimate sea surface temperatures to better than 1.0 degrees C relative to buoys. Daily composites of hourly GOES-8 sea surface temperatures are used to illustrate the capability of the GOES to produce improved cloud-free images of the ocean. Hourly time series reveal a 2 degrees C diurnal surface temperature cycle in the eastern subtropical Pacific with a peak near 1200 LT. The rapid onset of coastal upwelling along the southern coast of Mexico during December of 1996 was resolved at hourly intervals. C1 RES & DATA SYST CORP,GREENBELT,MD. RP Legeckis, R (reprint author), NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,OFF RES & APPLICAT,WASHINGTON,DC 20233, USA. RI Legeckis, Richard/F-5604-2010 NR 9 TC 21 Z9 22 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 SEP PY 1997 VL 78 IS 9 BP 1971 EP 1983 DI 10.1175/1520-0477(1997)078<1971:SSTFTG>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YA066 UT WOS:A1997YA06600007 ER PT J AU Westwater, ER AF Westwater, ER TI Remote sensing of tropospheric temperature and water vapor by integrated observing systems - The remote sensing lecture SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article; Proceedings Paper CT 1st Symposium on Integrated Observing Systems at the 77th Annual Meeting of the American-Meteorological-Society CY FEB 04, 1997 CL LONG BEACH, CA SP Amer Meteorol Soc ID CHANNEL MICROWAVE RADIOMETER; ATMOSPHERIC-TEMPERATURE; PRECIPITABLE WATER; RAMAN LIDAR; TIROS-N; MOISTURE MEASUREMENTS; WIND PROFILER; LIQUID WATER; SATELLITE; HUMIDITY AB In the last decade, substantial advances have been made in the remote sensing of tropospheric temperature and water vapor. Techniques include measurement of virtual temperature by Radio Acoustic Sounding Systems (RASS), the combination of RASS with satellite soundings, the measurement of precipitable water vapor by Global Positioning Systems, the measurement of water vapor profiles by Raman and differential absorption lidar, and the measurement of both temperature and water vapor profiles by Fourier Transform Infrared Radiometers. However, none of the techniques, by it self, is capable of satisfying most meteorological and climate needs. Thus, determination of profiles from combinations of data and sensors is the only practical way of satisfying these needs. In this paper, some of the techniques used for combining remote sensor data are outlined, some of the current sensors are described, and then examples of data derived from these combinations are presented. The role of the radiosonde in remote sensor evaluation, retrievals, and calibration is discussed. Finally, some of the new possibilities for combined remote sensors are presented. RP Westwater, ER (reprint author), UNIV COLORADO, NOAA, COOPERAT INST RES ENVIRONM SCI, ENVIRONM TECHNOL LAB, BOULDER, CO 80309 USA. NR 93 TC 19 Z9 19 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD SEP PY 1997 VL 78 IS 9 BP 1991 EP 2006 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YA066 UT WOS:A1997YA06600009 ER PT J AU Krishnakumar, PK Casillas, E Varanasi, U AF Krishnakumar, PK Casillas, E Varanasi, U TI Cytochemical responses in the digestive tissue of Mytilus edulis complex exposed to microencapsulated PAHs or PCBs SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-PHARMACOLOGY TOXICOLOGY & ENDOCRINOLOGY LA English DT Article DE biological indicators; cytochemical responses; detoxification enzymes; Mytilus edulis complex; PAHs; PCBs ID POLYCYCLIC AROMATIC-HYDROCARBONS; COMMON MUSSEL; GLAND MICROSOMES; PUGET-SOUND; CONTAMINANTS; CELLS; WORKSHOP; POLLUTANTS; WASHINGTON; POLLUTION AB Cytochemical responses in the digestive tissue of Mytilus edulis complex fed a microencapsulated mixture of PAHs (composed of phenanthrene, fluoranthene and benzo[a]pyrene) or PCBs (Aroclor 1254) were evaluated. Lysosomal membrane labilization period and lipofuscin content of digestive tissue were significantly decreased and increased, respectively, after 30 days of exposure to PAHs but not PCBs. NADPH-ferrihemoprotein reductase activity in the digestive tissue was significantly increased after 30 days exposure to both PAHs and PCBs, whereas catalase activity was significantly increased only after exposure to PCBs. Neutral lipid content and gamma-glutamyl transpeptidase activity of digestive tissue of mussels were significantly increased and decreased, respectively, after 30 days exposure to both PAHs and PCBs when compared to untreated mussels, but were not significantly different when compared to mussels treated with com oil representing the vehicle control. Exposure to PAHs induced peroxisome proliferation in the digestive tissue of M. edulis complex. The observed cytochemical responses in the digestive tissue of M. edulis complex exposed to PAHs and PCBs in the laboratory are comparable to the cytochemical responses observed in the digestive tissue of mussels collected in the field from sites contaminated with predominantly PAHs and PCBs. (C) 1997 Elsevier Science Inc. C1 NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,ENVIRONM CONSERVAT DIV,SEATTLE,WA 98112. CENT MARINE FISHERIES RES INST,RES CTR,MANGALORE 575001,INDIA. NR 30 TC 46 Z9 49 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0742-8413 J9 COMP BIOCHEM PHYS C JI Comp. Biochem. Physiol. C-Pharmacol. Toxicol. Endocrinol. PD SEP PY 1997 VL 118 IS 1 BP 11 EP 18 DI 10.1016/S0742-8413(97)00076-5 PG 8 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology SC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology GA XZ813 UT WOS:A1997XZ81300003 ER PT J AU Richards, GP Liang, YM Chao, JL Chao, L AF Richards, GP Liang, YM Chao, JL Chao, L TI Purification, characterization and activation of fish muscle prokallikrein SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-PHARMACOLOGY TOXICOLOGY & ENDOCRINOLOGY LA English DT Article DE fish muscle kallikrein; perfusion chromatography; evolution; serine proteinase; physiological function ID TISSUE KALLIKREIN; SUBSTRATE SPECIFICITIES; BRADYKININ; KININS; PLASMA AB Fish prokallikrein was isolated and characterized from skeletal muscle of the black sea bass, Centropristis striata. The prokallikrein was purified to apparent homogeneity by anion exchange perfusion chromatography and reversed phase high performance liquid chromatography. Initial identification was by its weak immunoreactivity with human tissue kallikrein antiserum. Two dimensional gel electrophoresis and immunoblotting identified the protein as 36 kDa with a pI of 4.95-5.15. The prokallikrein was trypsin-activated to produce an approximately 36 kDa active enzyme as identified on an SDS-polyacrylamide gel overlayed with a membrane impregnated with the fluorogenic tripeptidyl substrate D-Val-Leu-Arg-7-amino-4-trifluoromethylcoumarin. A potential dimer at 72 kDa was also enzymatically active. Bass kallikrein cleaved low molecular weight dog kininogen to release kinin, peptide as determined by radioimmunoassay. The enzyme's amidolytic activity, with a pH optimum at 9.0, was inhibited by aprotinin, benzamidine, and phenylmethanesulphonyl fluoride, but not by elastatinal, soybean trypsin inhibitor, or limabean trypsin inhibitor. Polyclonal antiserum raised against the purified bass muscle prokallikrein recognized 36 kDa and 72 kDa proteins in bass heart, skeletal muscle, spleen, swimbladder, gill, and kidney by Western blot analyses. The wide distribution of immunoreactive proteins in the tissues suggests a potential physiological role for fish kallikreins in muscle contraction and/or relaxation, the regulation of local blood flow, and in osmoregulation. The detection of fish prokallikrein and its activation leads the way for an evaluation of the impact of kallikreins in fish health and disease processes and for studying the evolution of kallikreins and related serine proteinases. (C) 1997 Elsevier Science Inc. C1 MED UNIV S CAROLINA,DEPT BIOCHEM & MOL BIOL,CHARLESTON,SC 29425. RP Richards, GP (reprint author), US DEPT COMMERCE,NOAA,NATL MARINE FISHERIES SERV,219 FT JOHNSON RD,CHARLESTON,SC 29412, USA. FU NHLBI NIH HHS [HL 29397] NR 23 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0742-8413 J9 COMP BIOCHEM PHYS C JI Comp. Biochem. Physiol. C-Pharmacol. Toxicol. Endocrinol. PD SEP PY 1997 VL 118 IS 1 BP 39 EP 48 DI 10.1016/S0742-8413(97)00030-3 PG 10 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology SC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology GA XZ813 UT WOS:A1997XZ81300007 PM 9366034 ER PT J AU Richards, GP Chao, L Chao, JL AF Richards, GP Chao, L Chao, JL TI Distribution of tissue kallikreins in lower vertebrates: Potential physiological roles for fish kallikreins SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-PHARMACOLOGY TOXICOLOGY & ENDOCRINOLOGY LA English DT Article DE alligator; bass; fish muscle kallikrein; immunoblot; mole; shark; sturgeon; tissue specificity ID RAT ANTERIOR-PITUITARY; GLANDULAR KALLIKREIN; RENAL KALLIKREIN; KININ SYSTEM; MESSENGER-RNA; HYBRIDIZATION HISTOCHEMISTRY; GENE-EXPRESSION; LOCALIZATION; IDENTIFICATION; KIDNEY AB Fish skeletal muscle prokallikrein was purified from black sea bass, Centropristis striata, and used for the production of polyclonal antiserum. Tissue proteins from primitive fish and teleosts, an alligator, and an insectivore were resolved by sodium dodecylsulfate-polyacrylamide gel electrophoresis, Western blotted, and probed with fish muscle prokallikrein antiserum. A recurring theme was the presence of approximately 36 and 72 kDa kallikrein-like proteins in skeletal muscle, heart, girl, kidney, and spleen of higher teleosts and in selected tissues of sturgeon, shark, alligator, and mole. The presence of immunoreactive kallikreins in osmoregulatory organs such as the gills of teleosts and the rectal gland of sharks signifies a potential role for these proteins in osmoregulation. Black sea bass, rock bass, and sturgeon contained many immunoreactive kallikreins in their swimbladders, which implicates a role for kallikreins in the regulation of blood flow and vascular permeability to facilitate gas exchange within the bladder. Kallikreins were consistently identified in skeletal muscle and heart of all the species evaluated and may regulate local blood flow, muscle contraction or relaxation, or participate in various transport processes. The antiserum to fish prokallikrein recognized immunoreactive kallikreins from pancreatic tissues from fish and lower vertebrates, but not from the pyloric caecum of sea bass. The wide distribution of tissue kallikrein in lower vetebrates suggests that it may participate in a variety of physiological functions. (C) 1997 Elsevier Science Inc. C1 MED UNIV S CAROLINA,DEPT BIOCHEM & MOL BIOL,CHARLESTON,SC 29425. RP Richards, GP (reprint author), NOAA,NATL MARINE FISHERIES SERV,US DEPT COMMERCE,219 FORT JOHNSON RD,CHARLESTON,SC 29412, USA. NR 67 TC 11 Z9 11 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0742-8413 J9 COMP BIOCHEM PHYS C JI Comp. Biochem. Physiol. C-Pharmacol. Toxicol. Endocrinol. PD SEP PY 1997 VL 118 IS 1 BP 49 EP 58 DI 10.1016/S0742-8413(97)00031-5 PG 10 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology SC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology GA XZ813 UT WOS:A1997XZ81300008 PM 9366035 ER PT J AU Garcia, F Sriram, RD AF Garcia, F Sriram, RD TI Developing knowledge sources to identify and evaluate tradeoffs among alternate designs in a cooperative engineering framework SO CONCURRENT ENGINEERING-RESEARCH AND APPLICATIONS LA English DT Article DE cooperative engineering; design evaluation; tradeoff analysis AB Current computer aided engineering tools support only a single specialized area of the design cycle and do not allow for comparisons of multiple designs. The DICE project at MIT (1987-1995) sought to address these limitations by developing tools that support a cooperative design cycle involving negotiation by various experts as the design evolves. CONGEN, a system developed under DICE, provides a blackboard-like context mechanism for negotiation and a knowledge base of design strategies. We propose a means of extending the knowledge base with a set of design evaluation Knowledge sources to assist in comparing alternate designs and identifying the tradeoffs among them. C1 NIST,MSID,ENGN DESIGN TECHNOL GRP,GAITHERSBURG,MD 20899. RP Garcia, F (reprint author), TEKNOWLEDGE CORP,4350 N FAIRFAX DR,SUITE 420,ARLINGTON,VA 22203, USA. NR 14 TC 2 Z9 2 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 1063-293X J9 CONCURRENT ENG-RES A JI Concurrent Eng.-Res. Appl. PD SEP PY 1997 VL 5 IS 3 BP 279 EP 292 DI 10.1177/1063293X9700500307 PG 14 WC Computer Science, Interdisciplinary Applications; Engineering, Manufacturing; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA YD700 UT WOS:A1997YD70000007 ER PT J AU Tunnicliffe, V Embley, RW Holden, JF Butterfield, DA Massoth, GJ Juniper, SK AF Tunnicliffe, V Embley, RW Holden, JF Butterfield, DA Massoth, GJ Juniper, SK TI Biological colonization of new hydrothermal vents following an eruption on Juan de Fuca Ridge SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID EAST PACIFIC RISE; 1993 COAXIAL EVENT; RECENT LAVA FLOWS; VOLCANIC-ERUPTION; SUBMERSIBLE OBSERVATIONS; CLEFT SEGMENT; SEA; VESTIMENTIFERA; PLUMES; COMMUNITIES AB A recent eruption on CoAxial Segment of Juan de Fuca Ridge initiated hydrothermal conditions with rapid changes in water chemistry and growth of microbial communities. Vent animals recruited from distal sources within a year. One site with newly erupted lava attracted no animals to high-iron and low-sulphide conditions. However, sustained release of flocculent material at a second site suggests extensive subterranean microbial production; here, the dissolved sulphide/heat ratio peaked during the first year. The first larval recruits included vestimentiferans, alvinellid polychaetes and nemerteans; despite the small areal extent of venting, one-third of the regional vent species pool had arrived by 2 years. Near-optimal growth conditions and recruitment by many species continued in the centre of the system but several habitats went extinct within 2 years. Rapid response and exploitation by vent animals must be an important adaptation to such ephemeral conditions. (C) 1997 Elsevier Science Ltd. C1 NOAA,HATFIELD MARINE SCI CTR,PACIFIC MARINE ENVIRONM LAB,NEWPORT,OR 97365. UNIV WASHINGTON,SCH OCEANOG,SEATTLE,WA 98195. NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. UNIV QUEBEC,DEPT SCI BIOL,MONTREAL,PQ H3C 3P8,CANADA. RP Tunnicliffe, V (reprint author), UNIV VICTORIA,SCH EARTH & OCEAN SCI,VICTORIA,BC V8W 3P6,CANADA. RI Holden, James/E-6815-2013; Tunnicliffe, Verena/D-1056-2014; Butterfield, David/H-3815-2016 OI Butterfield, David/0000-0002-1595-9279 NR 48 TC 88 Z9 88 U1 2 U2 18 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 SEP-OCT PY 1997 VL 44 IS 9-10 BP 1627 EP & DI 10.1016/S0967-0637(97)00041-1 PG 17 WC Oceanography SC Oceanography GA YF352 UT WOS:A1997YF35200007 ER PT J AU Kula, K McKinney, JE Kula, TJ AF Kula, K McKinney, JE Kula, TJ TI Effects of daily topical fluoride gels on resin composite degradation and wear SO DENTAL MATERIALS LA English DT Article ID IN-VITRO WEAR; DENTAL COMPOSITES; REINFORCING FILLERS; CANCER-PATIENTS; WATER; LEACHABILITY; STORAGE; SURFACE; CARIES AB Objectives. This in vitro study compares the effects of professional and consumer-applied topical fluorides on the weight, wear resistance and surface appearance of a resin composite containing barium boroaluminosilicate glass filler particles. Methods. Prior to wear studies with a pin and disc apparatus, specimens were immersed for 6 min 10 times in water, three consumer-applied topical fluorides (1.1% NaF, 0.4% SnF2, or 0.5% APF gel) or a professionally applied topical fluoride (1.23% APF gel). Specimens were weighed before and after each immersion. Following wear studies, the specimen surfaces were visually evaluated using scanning electron microscopy. Weight changes were analyzed for significant differences using one-way ANOVA and Duncan's multiple range test (p = 0.01). Values of wear parameters were ranked and tested for significance using one-way ANOVA with least squares mean contrast (p = 0.05). Results. Significant differences were found in the weight loss of specimens treated with different fluoride agents: 1.23% APF = 0.5% APF > 0.4% SnF2, > 1.1% NaF = water (p less than or equal to 0.0001). Significant differences in initial wear depth (S-l) occurred in the following samples: 1.23%APF > 1.1% NaF = 0.5% APF (p = 0.04). Scanning electron micrographs showed variable wear tracks on the specimen surfaces. The specimen surfaces outside the wear track were smooth for those treated with water or with NaF; the surfaces outside the wear track of specimens treated with APF showed extensive loss of filler particles. Significance. Topical APF agents caused extensive loss of filler from the resin composite specimens whereas 1.1% NaF caused the least damage. Although significant differences in surface wear resistance were detected, clinical studies are needed to determine the effect of topical fluorides on the properties of this resin composite. C1 Univ Missouri, Sch Dent, Dept Orthodont & Dentofacial Orthoped, Kansas City, MO 64108 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Kula, K (reprint author), Univ Missouri, Sch Dent, Dept Orthodont & Dentofacial Orthoped, 650 E 25th St, Kansas City, MO 64108 USA. EM kulak@smtpgate.umkc.edu NR 41 TC 17 Z9 18 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0109-5641 J9 DENT MATER JI Dent. Mater. PD SEP-NOV PY 1997 VL 13 IS 5-6 BP 305 EP 311 DI 10.1016/S0109-5641(97)80100-5 PG 7 WC Dentistry, Oral Surgery & Medicine; Materials Science, Biomaterials SC Dentistry, Oral Surgery & Medicine; Materials Science GA 127AJ UT WOS:000076327300003 PM 9823090 ER PT J AU Pastorok, RA MacDonald, A Sampson, JR Wilber, P Yozzo, DJ Titre, JP AF Pastorok, RA MacDonald, A Sampson, JR Wilber, P Yozzo, DJ Titre, JP TI An ecological decision framework for environmental restoration projects SO ECOLOGICAL ENGINEERING LA English DT Article DE habitat restoration; ecological planning; landscape design; adaptive management ID WETLAND AB Ecosystem restoration projects require planning and monitoring to maximize project success relative to costs, yet many projects completed thus far have been planned on an ad hoc, consensus basis and are virtually ignored after revegetation at the site is complete. We describe a formalized planning process geared specifically to the needs of ecological restoration projects (and ecosystem rehabilitation or management projects; National Research Council, 1992). This process emphasizes: 1) the importance of defining objectives related to the appropriate ecosystem structure, function, and spatial scale; 2) the role of ecological models, restoration hypotheses, and key ecological parameters; 3) explicit consideration of uncertainties in site processes and material performance in the restoration design; 4) guidelines for project design and feasibility analysis and the use of experimentation at this stage; and 5) monitoring and adaptive management of restoration projects after implementation of a design. This process was developed to integrate a fundamental understanding of ecological principles into the existing project planning framework used by the U.S. Army Corps of Engineers in their growing role in restoration of aquatic habitats, but it should be applied to terrestrial habitats as well. (C) 1997 Elsevier Science B.V. C1 PTI,ENVIRONM SERV,BOULDER,CO 80301. NOAA,COASTAL SERV CTR,CCEH,CHARLESTON,SC 29405. USA,CORPS ENGINEERS,WATERWAYS EXPT STN,ENVIRONM LAB,VICKSBURG,MS 39180. RP Pastorok, RA (reprint author), PTI,ENVIRONM SERV,15375 SE 30TH PL,SUITE 250,BELLEVUE,WA 98007, USA. NR 40 TC 35 Z9 45 U1 2 U2 22 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-8574 J9 ECOL ENG JI Ecol. Eng. PD SEP PY 1997 VL 9 IS 1-2 BP 89 EP 107 DI 10.1016/S0925-8574(97)00036-0 PG 19 WC Ecology; Engineering, Environmental; Environmental Sciences SC Environmental Sciences & Ecology; Engineering GA YA301 UT WOS:A1997YA30100006 ER PT J AU Biswas, P Zachariah, MR AF Biswas, P Zachariah, MR TI In situ immobilization of lead species in combustion environments by injection of gas phase silica sorbent precursors SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID FLUORESCENCE; PARTICLES; REMOVAL; FLAMES; GROWTH AB A mechanistic study of the in situ immobilization of a toxic metal species in a high-temperature environment using gas phase sorbent precursors is described. Planar laser-based imaging measurements of fluorescence and particle scattering have been obtained to study the interaction of lead with silicon species in high-temperature oxidizing environments. The application of laser-induced fluorescence, the spectroscopy of PbO(g), and the techniques of measurement of gas phase precursors to particle formation are discussed. The silicon precursor is oxidized to form silica particles in the high temperatures, followed by a reactive scavenging of PbO(g). The result is that the lead oxide gas phase concentration is reduced, and homogenous nucleation of lead species is suppressed. The resultant particles are not only larger than a lead only case but also have morphologies in which lead is effectively immobilized and vitrified within a silica matrix. Trace quantities of silicon species have been shown to be effective in conversion of lead oxide to lead silicate. The measured conversion efficiencies of lead oxide to lead silicate agree well with equilibrium calculations, and no rate limitations were observed. C1 NIST,CHEM SCI & TECHNOL LAB,PROC MEASUREMENT DIV,GAITHERSBURG,MD 20899. RP Biswas, P (reprint author), UNIV CINCINNATI,DEPT CIVIL & ENVIRONM ENGN,AEROSOL & AIR QUAL RES LAB,CINCINNATI,OH 45221, USA. NR 31 TC 47 Z9 48 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD SEP PY 1997 VL 31 IS 9 BP 2455 EP 2463 DI 10.1021/es9700663 PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XU118 UT WOS:A1997XU11800029 ER PT J AU AlSheikhly, M Silverman, J Neta, P Karam, L AF AlSheikhly, M Silverman, J Neta, P Karam, L TI Mechanisms of ionizing radiation-induced destruction of 2,6-dichlorobiphenyl in aqueous solutions SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID RADICAL-INDUCED OXIDATION; RATE CONSTANTS; PHENYLPEROXYL RADICALS; ABSORPTION-SPECTRA; PULSE-RADIOLYSIS; REMEDIATION; OXYGEN; KINETICS AB Polychlorinated biphenyls (PCBs) appear as environmental pollutants in Various phases. Aqueous media polluted with such compounds may potentially be detoxified by electron beam irradiation. In the present study, we discuss the possible mechanisms of radiolytic detoxification under various conditions, and we study 2,6-dichlorobiphenyl (DCB) as a model compound for PCBs. Electron beam and gamma-irradiation of DCB in aqueous methanol solutions lead to degradation of this compound and formation of Cl- ions, but high doses are required. Solutions of 1 mmol L-1 DCB require a dose of 30 kGy to produce 1 equiv of Cl- (G = 0.03 mu mol J(-1)) to form the less toxic monachlorobiphenyl (MCB), but 600 kGy is required to achieve full dechlorination. This low yield is due to the concomitant formation of acid, which competes with DCB for the solvated electrons, the main reducing species in this system. The radiolytic yields are improved dramatically by the addition of carbonate; only 20 kGy are required far practically quantitative dechlorination of DCB. For the oxidation process, the dechlorination of DCB by (OH)-O-. radicals was measured in N2O-saturated solutions and found to be much less effective than the reduction process. C1 NIST,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. NIST,IONIZING RADIAT DIV,GAITHERSBURG,MD 20899. RP AlSheikhly, M (reprint author), UNIV MARYLAND,DEPT MAT & NUCL ENGN,COLLEGE PK,MD 20742, USA. NR 28 TC 31 Z9 34 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD SEP PY 1997 VL 31 IS 9 BP 2473 EP 2477 DI 10.1021/es960741t PG 5 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XU118 UT WOS:A1997XU11800032 ER PT J AU Grosshandler, WL AF Grosshandler, WL TI Towards the development of a universal fire emulator-detector evaluator SO FIRE SAFETY JOURNAL LA English DT Article; Proceedings Paper CT 10th International Conference on Automatic Fire Detection (AUBE 95) CY APR, 1995 CL GERHARD MERCATOR UNIV, DUISBURG, GERMANY HO GERHARD MERCATOR UNIV ID SMOKE AB Past measurements are examined of CO, CO2, H2O, H-2, O-2, smoke and temperature produced in standard fires of the UL and EN type. Additional measurements just above the heat release zone are suggested to obtain a more complete footprint of each standard fire, and the concept of a universal fire emulator-detector evaluator (FE-DE) is introduced. The objective of the emulator is to produce more well-controlled environments that eliminate the unavoidable run-to-run variations associated with full-scale tests. Numerical fluid dynamic computations are recommended to insert the fire source into the space being protected as a guide for detector placement and to predict system performance under realistic conditions. Published by Elsevier Science Ltd. RP Grosshandler, WL (reprint author), NIST,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899, USA. NR 23 TC 10 Z9 11 U1 1 U2 1 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 SEP-OCT PY 1997 VL 29 IS 2-3 BP 113 EP 127 DI 10.1016/S0379-7112(96)00031-8 PG 15 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA YC909 UT WOS:A1997YC90900005 ER PT J AU Davis, WD Forney, GP Bukowski, RW AF Davis, WD Forney, GP Bukowski, RW TI Developing detector siting rules from computational experiments in spaces with complex geometries SO FIRE SAFETY JOURNAL LA English DT Article; Proceedings Paper CT 10th International Conference on Automatic Fire Detection (AUBE 95) CY APR, 1995 CL GERHARD MERCATOR UNIV, DUISBURG, GERMANY HO GERHARD MERCATOR UNIV AB The National Institute of Standards and Technology (NIST) is conducting a 4-year research project wherein a computational fluid dynamics (CFD) computer code is utilized to map temperature, flow velocities, and particle densities in spaces with complex ceiling geometries. Through parametric variation of independent variables for the fire and the space, the number and location of smoke or thermal sensors required to assure response prior to a critical fire size is determined. The first year addressed horizontal ceilings with open beams or joists, and the second year adds sloped ceilings. In addition to the geometric studies, several special studies have been conducted. These include detection of low energy fires (as low as 100 W), stratification of fire gases in spaces with a vertical thermocline which exceeds the plume temperature, and obstructions which do not come completely to the ceiling. A unique method of relating the response of detectors to the predicted conditions has been developed which can be utilized with ally CFD model or with experimental data. The data analysis is being used to produce siting rules for inclusion directly into existing codes. The paper will review the results of the first 2 years of the project and present some thoughts on the potential far these techniques to greatly improve the technical basis for the utilization of fire sensors in complex installations. Published by Elsevier Science Ltd. RP Davis, WD (reprint author), NIST,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899, USA. NR 12 TC 5 Z9 5 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 SEP-OCT PY 1997 VL 29 IS 2-3 BP 129 EP 139 DI 10.1016/S0379-7112(96)00052-5 PG 11 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA YC909 UT WOS:A1997YC90900006 ER PT J AU Sorathia, U Lyon, R Gann, RG Gritzo, L AF Sorathia, U Lyon, R Gann, RG Gritzo, L TI Materials and fire threat SO FIRE TECHNOLOGY LA English DT Article C1 FAA TECH CTR,FIRE RES,ATLANTIC CITY INT AIRPORT,ATLANTIC CITY,NJ. NATL INST STAND & TECHNOL,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Sorathia, U (reprint author), USN,CARDEROCK SURFACE WARFARE CTR,ANNAPOLIS,MD 21402, USA. NR 23 TC 17 Z9 18 U1 1 U2 4 PU NATIONAL FIRE PROTECTION ASSOC PI QUINCY PA ONE BATTERYMARCH PK, QUINCY, MA 02269 SN 0015-2684 J9 FIRE TECHNOL JI Fire Technol. PD SEP-OCT PY 1997 VL 33 IS 3 BP 260 EP 275 DI 10.1023/A:1015371806854 PG 16 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA XW186 UT WOS:A1997XW18600007 ER PT J AU Landsea, CW Nicholls, N Gray, WM Avila, LA AF Landsea, CW Nicholls, N Gray, WM Avila, LA TI Downward trends in the frequency of intense Atlantic hurricanes during the past 5 decades - Reply SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material C1 BUR METEOROL,RES CTR,MELBOURNE,VIC 3001,AUSTRALIA. COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523. NOAA,NATL HURRAINCE CTR,MIAMI,FL 33165. RP Landsea, CW (reprint author), NOAA,AOML,HURRICANE RES DIV,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Nicholls, Neville/A-1240-2008 NR 3 TC 3 Z9 3 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 SEP 1 PY 1997 VL 24 IS 17 BP 2205 EP 2205 DI 10.1029/97GL02109 PG 1 WC Geosciences, Multidisciplinary SC Geology GA XU257 UT WOS:A1997XU25700026 ER PT J AU Mofjeld, HO Foreman, MGG Ruffman, A AF Mofjeld, HO Foreman, MGG Ruffman, A TI West Coast tides during Cascadia subduction zone tsunamis SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EARTHQUAKES AB Low, neap tides occurred along the West Coast of the United States and Canada around 0500 UT January 27, 1700, a time for the last major Cascadia earthquake/tsunami based on teletsunami arrival times in Japan [Satake et al., 1996]. However, high-range perigean spring tides occurred only a week later, illustrating how accurately occurrence times must be known to constrain the region's background water levels during such events. The ranges of background water levels increase northward from 3 m at Monterey to 8.5 m at Queen Charlotte, as estimated from the amplitudes of perigean spring tides and subtidal winter fluctuations. C1 FISHERIES & OCEANS CANADA INST OCEAN SCI, SIDNEY, BC V8L 4B2, CANADA. GEOMARINE ASSOCIATED LTD, HALIFAX, NS B3J 2L4, CANADA. RP NOAA, PACIFIC MARINE ENVIRONM LAB, 7600 SAND POINT WAY NE, SEATTLE, WA 98115 USA. NR 22 TC 10 Z9 10 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 SEP 1 PY 1997 VL 24 IS 17 BP 2215 EP 2218 DI 10.1029/97GL02060 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XU257 UT WOS:A1997XU25700029 ER PT J AU Christophorou, LG Olthoff, JK VanBrunt, RJ AF Christophorou, LG Olthoff, JK VanBrunt, RJ TI Sulfur hexafluoride and the electric power industry SO IEEE ELECTRICAL INSULATION MAGAZINE LA English DT Article DE circuit breakers; gas-insulated transformers; gas-insulated transmission lines; greenhouse effect; high voltage insulation ID MIXTURES; GASES; SF6 C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. RP Christophorou, LG (reprint author), NIST,US DEPT COMMERCE,BLDG 220,ROOM B344,GAITHERSBURG,MD 20899, USA. NR 31 TC 99 Z9 110 U1 5 U2 19 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0883-7554 J9 IEEE ELECTR INSUL M JI IEEE Electr. Insul. Mag. PD SEP-OCT PY 1997 VL 13 IS 5 BP 20 EP 24 DI 10.1109/57.620514 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA XX883 UT WOS:A1997XX88300005 ER PT J AU Milanovic, V Gaitan, M Bowen, ED Tea, NH Zaghloul, ME AF Milanovic, V Gaitan, M Bowen, ED Tea, NH Zaghloul, ME TI Thermoelectric power sensor for microwave applications by commercial CMOS fabrication SO IEEE ELECTRON DEVICE LETTERS LA English DT Article AB This letter describes an implementation of a thermoelectric microwave power sensor fabricated through commercial CMOS process with additional maskless etching, The sensor combines micromachined coplanar waveguide and contact pads, a microwave termination which dissipates heat proportionally to input microwave power, and many aluminum-polysilicon thermocouples, The device was designed and fabricated in standard CMOS technology, including the appropriate superimposed dielectric openings for post-fabrication micromachining. By removing the bulk silicon located beneath the device through micromachining, thermal and electromagnetic losses are minimized, The sensor measures signal true rms power in the frequency range up to 20 GHz with input power in the -30 dBm to +10 dBm range, Over this 40 dB dynamic range, output voltage versus input power is linear within less than +/-0.16%. Automatic network analyzer data show an acceptable input return loss of less than -30 dB over the entire frequency range. C1 NATL INST STAND & TECHNOL,DIV SEMICOND ELECT,GAITHERSBURG,MD 20899. RF MICROSYST INC,SAN DIEGO,CA 92123. RP Milanovic, V (reprint author), GEORGE WASHINGTON UNIV,DEPT ELECT ENGN & COMP SCI,WASHINGTON,DC 20052, USA. NR 13 TC 47 Z9 58 U1 0 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD SEP PY 1997 VL 18 IS 9 BP 450 EP 452 DI 10.1109/55.622527 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA XR893 UT WOS:A1997XR89300016 ER PT J AU Russek, SE Oti, JO Kim, YK Cross, RW AF Russek, SE Oti, JO Kim, YK Cross, RW TI Field angle and current density effects in submicrometer spin valves for digital applications SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE AB We have characterized the magnetoresistive response of giant magnetoresistive spin valve devices, designed for digital applications, as a function of current density and magnetic field angle. The devices are designed to have only two stable states and are characterized by their positive and negative switching fields. The variations in the switching fields of submicrometer devices are compared with a multilayer single-domain model to determine how accurately the switching fields can be predicted. Significant deviation from single domain behavior is observed. Structure in the magnetoresistive response curve, indicating stable micro-domains, is seen in devices with small line widths and small aspect ratios. At large field angles, the micro-domains are stable to high field values and can dramatically effect the switching process. The variation of the switching fields with bias current and field angle depart considerably from the single domain model predictions. C1 QUANTUM CORP,LOUISVILLE,CO 80027. RP Russek, SE (reprint author), NATL INST STAND & TECHNOL,DIV ELECTROMAGNET TECHNOL,BOULDER,CO 80303, USA. NR 3 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 3292 EP 3294 DI 10.1109/20.617921 PN 1 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW564 UT WOS:A1997XW56400222 ER PT J AU Oti, JO Russek, SE AF Oti, JO Russek, SE TI Micromagnetic simulations of magnetoresistive behavior of sub-micrometer spin-valve MRAM devices SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID THIN AB The effects of device shape and size on the giant magnetoresistive (MR) response of NiFe7.5nm/Co-0.6nm/Cu-3nm/Co-0.6nm/NiFe7.5nm/FeMn spin-valve magnetoresistive random access memory (MRAM) stripes are studied by micromagnetic simulation, Samples having aspect ratios of 10:1, 3:1 and 1.5:1, and line widths varying from 0.5 mu m to 1.5 mu m are simulated. The effects of the magnetostatic coupling between the magnetic layers and their self-demagnetization are studied. RP Oti, JO (reprint author), NATL INST STAND & TECHNOL,DIV ELECTROMAGNET TECHNOL,BOULDER,CO 80303, USA. NR 7 TC 19 Z9 19 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 3298 EP 3300 DI 10.1109/20.617923 PN 1 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW564 UT WOS:A1997XW56400224 ER PT J AU Kos, AB Russek, SE Kim, YK Cross, RW AF Kos, AB Russek, SE Kim, YK Cross, RW TI High current density measurements of giant magnetoresistive spin-valves for magnetic recording and sensor applications SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE AB High current density measurements on giant magnetoresistive NiFe-Cu-NiFe-FeMn spin-valve devices are presented. The spin-valve magnetoresistive response, Delta R/R, is highly temperature dependent; at temperatures near the blocking temperature there is a considerable reduction of pinning field and decrease in device response. It is desirable to measure certain high current density effects such as electromigration and self-field effects separately from the effects of ohmic heating. For this purpose, we introduce pulsed current techniques necessary to reduce ohmic heating in wafer-level device measurements and we deduce a required pulse width of 15 ns to minimize device heating. C1 QUANTUM CORP,LOUISVILLE,CO 80027. RP Kos, AB (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 2 TC 13 Z9 14 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 3541 EP 3543 DI 10.1109/20.619491 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500014 ER PT J AU Egelhoff, WF Chen, PJ Powell, CJ Stiles, MD McMichael, RD Judy, JH Takano, K Berkowitz, AE Daughton, JM AF Egelhoff, WF Chen, PJ Powell, CJ Stiles, MD McMichael, RD Judy, JH Takano, K Berkowitz, AE Daughton, JM TI Specular electron scattering in giant magnetoresistance spin valves SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID LAYERED MAGNETIC-STRUCTURES; GOLD-FILMS; CONDUCTIVITY; RESISTIVITY; RESISTANCE; METAL; AG AB Specular scattering of electrons at the top surface of bottom spin valves has been found to contribute to the giant magnetoresistance effect. The specular scattering can be increased bg the deposition of similar to 2 monolayers (ML) of Au, Ag, or Cu, with the result that the GMR increases and the R-square decreases. The deposition of 2 ML of species that disorder the surface, such as Ta, Si, C, or N80F20, suppresses the specular scattering, This suppression appears to be useful as a new method for evaluating the importance of specular scattering. C1 UNIV MINNESOTA,MINNEAPOLIS,MN 55455. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. NONVOLATILE ELECT INC,EDEN PRAIRIE,MN 55344. RP Egelhoff, WF (reprint author), NIST,GAITHERSBURG,MD 20899, USA. RI McMichael, Robert/J-8688-2012; Stiles, Mark/K-2426-2012 OI Stiles, Mark/0000-0001-8238-4156 NR 17 TC 36 Z9 37 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 3580 EP 3582 DI 10.1109/20.619503 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500026 ER PT J AU Kirschenbaum, LS Rogers, CT Russek, SE Kim, YK AF Kirschenbaum, LS Rogers, CT Russek, SE Kim, YK TI Low-frequency noise in NiFe/Cu spin-valves SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID MULTILAYERS AB We report one of the first observations of low-frequency noise of NiFe/Cu spin-valves. Although the observed noise is very low irt comparison to multilayer systems, if is; typically concentrated in the linear response region where such devices are expected to operate. Increased noise is also associated viith Barkhausen jumps in the magnetoresistance trace. In devices one micrometer high, structures start to appear in the noise spectra as a perturbation to the simple 1/f-like noise observed in larger devices. C1 NATL INST STAND & TECHNOL,DIV ELECTROMAGNET TECHNOL,BOULDER,CO 80303. QUANTUM CHEM CORP,LOUISVILLE,CO 80027. RP Kirschenbaum, LS (reprint author), UNIV COLORADO,CONDENSED MATTER LAB,BOULDER,CO 80309, USA. NR 4 TC 10 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 3586 EP 3588 DI 10.1109/20.619505 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500028 ER PT J AU McMichael, RD Chen, PJ Egelhoff, WF AF McMichael, RD Chen, PJ Egelhoff, WF TI Anomalous properties of spin valves at elevated temperatures SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID GIANT-MAGNETORESISTANCE; CO/CU MULTILAYERS AB We present results of magnetoresistance measurements on a 50 nm NiO\2.7 nm Co\2.2 nm Cu\3.1 nm Co\2.5 nm Au spin valve performed in vacuum at temperatures up to 400 degrees C. Values of Delta R/R, R, and coercivities were found to be reversible up to 200 degrees C. Irreversible changes in transport properties observed at and above 250 degrees C were concurrent with changes in the interlayer coupling. A striking result is that the coercivity of the NiO-coupled Co film remains large for temperatures at and above the Neel temperature of NiO. Evidence is presented for the existence of 'coercivity transfer' between the Co layers. RP McMichael, RD (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. RI McMichael, Robert/J-8688-2012; OI McMichael, Robert/0000-0002-1372-664X NR 15 TC 6 Z9 6 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 3589 EP 3591 DI 10.1109/20.619506 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500029 ER PT J AU Crawford, TM Rogers, CT Silva, TJ Kim, YK AF Crawford, TM Rogers, CT Silva, TJ Kim, YK TI Second-harmonic magneto-optic Kerr effect from spin-valve test structures: Correlation with magnetoresistance response SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID THIN-FILM STRUCTURES; 2ND-HARMONIC GENERATION; GIANT MAGNETORESISTANCE; MULTILAYERS; TRANSVERSE; SURFACES AB We have simultaneously measured the second-harmonic magneto-optic Kerr effect and the magnetoresistance of patterned Ta/Ni81Fe19/Cu/Ni81Fe19/Ta spin-valve test structures. For fields applied parallel to the bias-current direction, we observed a one-to-one correlation between the magnetoresistance and the magnetization-dependent second-harmonic intensity. The dependence of the second-harmonic intensity. The dependence of the second-harmonic response arises largely from the top Ni81Fe19/Ta interface. The existence of this one-to-one correlation implies that the second harmonic depends linearly on magnetization, thus offering a method for interface-specific magnetometry. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. QUANTUM CHEM CORP,LOUISVILLE,CO 80027. RP Crawford, TM (reprint author), UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309, USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 13 TC 2 Z9 2 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 3598 EP 3600 DI 10.1109/20.619509 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500032 ER PT J AU Nikitenko, VI Dedukh, LM Gornakov, VS Kabanov, YP Bennett, LH Donahue, MJ Swartzendruber, LJ Shapiro, AJ Brown, HJ AF Nikitenko, VI Dedukh, LM Gornakov, VS Kabanov, YP Bennett, LH Donahue, MJ Swartzendruber, LJ Shapiro, AJ Brown, HJ TI Spin reorientation transitions and domain structure in magnetic multilayers SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID ANISOTROPY; LAYERS AB Spin reorientation phase transitions and the evolution of the magnetic phases states arising during magnetization reversal of antiferromagnetic CoNiCu/Cu superlattice are studied using magneto-optical indicator film technique, accompanied by vector hysteresis loop measurements. The spin-flop and nonsymmetric angle phases have been found and analyzed. It is shown that they arise due to the nucleation and growth of domains. C1 GEORGE WASHINGTON UNIV,INST MAGNET RES,ASHBURN,VA 22011. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Nikitenko, VI (reprint author), RUSSIAN ACAD SCI,INST SOLID STATE PHYS,CHERNOGOLOVKA 142432,MOSCOW DISTRICT,RUSSIA. NR 8 TC 9 Z9 9 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 3661 EP 3663 DI 10.1109/20.619530 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500053 ER PT J AU Rice, P Russek, SE Hoinville, J Kelley, MH AF Rice, P Russek, SE Hoinville, J Kelley, MH TI Optimizing the NIST magnetic imaging reference sample SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID FORCE MICROSCOPY; TIPS AB We have further developed the NIST magnetic imaging reference sample to include a magnetic pattern which can indicate the magnetic polarity of a magnetic force microscope tip. Several samples cut from the same disk were measured with a single tip. We have also measured a single transition with several tips. Both measurements have shown the variability in images taken with different tips and different instrument configuration which underscores the need for a well calibrated sample. C1 MAXTOR CORP,LONGMONT,CO 80501. NIST,GAITHERSBURG,MD 20899. RP Rice, P (reprint author), NATL INST STAND & TECHNOL,BOULDER,CO 80303, USA. NR 7 TC 6 Z9 6 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 4065 EP 4067 DI 10.1109/20.619664 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500187 ER PT J AU Moreland, J Russek, SE Hopkins, PF AF Moreland, J Russek, SE Hopkins, PF TI Surface potential imaging for magnetoresistive head development SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID SCANNING-FORCE-MICROSCOPE; POTENTIOMETRY; RESOLUTION AB We demonstrate the first applications of scanning surface potential microscopy to magnetoresistive (MR) thin-film devices, Images are presented on active devices showing 2D maps of the surface potential of energized MR read-head stripes taken from the production line at the puck level, We have found that surface potential line scans (voltage vs, distance) along MR spin valve stripes show slight deviations from linearity, possibly due to nonuniform film magnetization along the length of the stripe. C1 QUANTUM PERIPHERALS COLORADO INC,LOUISVILLE,CO 80027. RP Moreland, J (reprint author), NATL INST STAND & TECHNOL,DIV ELECTROMAGNET TECHNOL,BOULDER,CO 80303, USA. NR 10 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 4068 EP 4070 DI 10.1109/20.619665 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500188 ER PT J AU Oti, JO Kim, YK Suvarna, S AF Oti, JO Kim, YK Suvarna, S TI A personal computer based semi-analytical micromagnetics design tool SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID SPIN-VALVE AB A personal computer based semi-analytical micromagnetics design tool is described, The program enables the flexible modeling of systems of interacting single-domain rectangular prisms. The program utilizes a convenient graphical windowing interface that facilitates the design and analysis of the system. Magnetization and magnetoresistive curve properties of the system are calculated by the program, A design example of the magnetoresistive responses of spin valves with partially overlapping magnetic layers is presented. C1 QUANTUM CORP,LOUISVILLE,CO 80028. UNIV COLORADO,DEPT ELECT ENGN,BOULDER,CO 80309. RP Oti, JO (reprint author), NATL INST STAND & TECHNOL,DIV ELECTROMAGNET TECHNOL,BOULDER,CO 80303, USA. NR 5 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 4119 EP 4121 DI 10.1109/20.619682 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500205 ER PT J AU McMichael, RD Donahue, MJ AF McMichael, RD Donahue, MJ TI Head to head domain wall structures in thin magnetic strips SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE AB We present calculations of head to head domain wall structures in magnetic strips of Ni80Fe20 with widths, w, ranging from 75 nm to 500 nm and thicknesses, t, from 1 nm to 64 nm, Neglecting magnetocrystalline and magnetostrictive anisotropy energies, minimization of exchange and magnetostatic energy leads to one of two types of domain wall structures: 'transverse' walls with magnetization at the center of the wall directed transverse to the strip axis and 'vortex' walls where the magnetization forms a vortex at the center of the wall, Calculation of the domain wall energies leads to a proposed phase diagram for head to head domain walls where transverse walls have lower energy when dimensions are less than t(crit)w(crit) approximate to 130A/mu(0)M(s)(2). RP McMichael, RD (reprint author), NIST,GAITHERSBURG,MD 20899, USA. RI McMichael, Robert/J-8688-2012; OI McMichael, Robert/0000-0002-1372-664X NR 9 TC 347 Z9 347 U1 4 U2 50 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 4167 EP 4169 DI 10.1109/20.619698 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500221 ER PT J AU Bennett, LH Swartzendruber, LJ Vajda, F DellaTorre, E Judy, JH AF Bennett, LH Swartzendruber, LJ Vajda, F DellaTorre, E Judy, JH TI Aftereffect and accommodation anisotropy in metal-particle and metal-evaporated recording media SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 35th Annual IEEE International Magnetics Conference (INTERMAG 97) CY APR 01-04, 1997 CL NEW ORLEANS, LA SP IEEE ID TIME-DEPENDENCE; MODEL AB Aftereffect and accommodation are measured in metal recording media using either evaporated cobalt (ME) or particulate iron (MP) as the magnetic material. These materials are highly anisotropic and measurements have been made parallel to the plane of the media both along the easy direction and along the hard direction. Along the easy direction, the Loops are square and there is only a smalt difference between the coercive field, H-c, and the remanent coercive field, H-ci. Along the hard direction the squareness is approximately one-half that along the easy axis and H-ci is shifted considerably from H-c. C1 GEORGE WASHINGTON UNIV,INST MAGNET RES,WASHINGTON,DC 20052. DIGITAL MEASUREMENT SYST INC,BURLINGTON,MA 01803. UNIV MINNESOTA,DEPT ELECT ENGN,CTR MICROMAGNET & INFORMAT TECHNOL,MINNEAPOLIS,MN 55455. RP Bennett, LH (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 11 TC 5 Z9 5 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1997 VL 33 IS 5 BP 4173 EP 4175 DI 10.1109/20.619700 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XW565 UT WOS:A1997XW56500223 ER PT J AU Zhang, F Chen, SL Chang, YA Kattner, UR AF Zhang, F Chen, SL Chang, YA Kattner, UR TI A thermodynamic description of the Ti-Al system SO INTERMETALLICS LA English DT Article DE Ti-Al system; point defects; phase diagram calculation; thermodynamic modelling; thermodynamic properties ID PHASE-DIAGRAM; ALLOYS; SOLIDIFICATION; MULTICOMPONENT; EQUILIBRIA; DEFECTS; MODEL AB A thermodynamic description of the Ti-Al system was developed in this study. Nine phases were considered and can be classified as three types - disordered solution phases: liquid, (alpha Ti, hcp), (beta Ti, bcc), (Al, fcc); ordered intermetallic phases: alpha(2)-Ti3Al (DO19), gamma-TiAl3 (DO22), TiAl3 (DO22); and stoichiometric phases: TiAl2 and Ti2Al5. While the Redlich-Kister equation was used to describe the excess Gibbs energy of the disordered solution phases, a generalized bond-energy model recently developed by us at the University of Wisconsin at Madison was used to describe the Gibbs energy of the ordered intermetallic phases. The model parameters were optimized using the experimental phase equilibrium and thermodynamic data available in the literature. The calculated phase diagram as well as the thermodynamic functions are in good agreement with experimental data. The intrinsic defect concentrations calculated from the model parameters for gamma-TiAl were found to be in accord with those obtained from a semiempirical relationship in terms of its enthalpy of formation and the available experimental data. The generalized bond-energy model parameters for the ordered intermetallic phases were converted to those of the compound energy model for the convenience of the users of Thermo-Gale. (C) 1997 Elsevier Science Limited. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Zhang, F (reprint author), UNIV WISCONSIN,DEPT MAT SCI & ENGN,1509 UNIV AVE,MADISON,WI 53706, USA. NR 45 TC 75 Z9 78 U1 3 U2 25 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD SEP PY 1997 VL 5 IS 6 BP 471 EP 482 DI 10.1016/S0966-9795(97)00030-7 PG 12 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA YB278 UT WOS:A1997YB27800008 ER PT J AU Pozo, R AF Pozo, R TI Template numerical toolkit for linear algebra: High performance programming with C++ and the standard template library SO INTERNATIONAL JOURNAL OF SUPERCOMPUTER APPLICATIONS AND HIGH PERFORMANCE COMPUTING LA English DT Article AB We present a new C++ library design for linear algebra computations on high performance architectures. The template numerical toolkit (TNT) for linear algebra is a successor to the Lapack++, Sparselib++, and IML++ packages, providing support for direct and iterative solvers. Its goal is to formally integrate these ideas into a generic algorithm library supporting user-defined data types and data neutrality. The design of the core library uses components from the C++ standard template library (STL) and the basic parallel extensions defined in High Performance C++ (HPC++). C1 NATL INST STAND & TECHNOL,APPL & COMPUTAT MATH DIV,GAITHERSBURG,MD 20899. NR 15 TC 7 Z9 7 U1 0 U2 0 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 1078-3482 J9 INT J SUPERCOMPUT AP JI Int. J. Supercomput. Appl. High Perform. Comput. PD FAL PY 1997 VL 11 IS 3 BP 251 EP 263 DI 10.1177/109434209701100307 PG 13 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Computer Science GA XL866 UT WOS:A1997XL86600007 ER PT J AU Slifka, AJ Smith, DR AF Slifka, AJ Smith, DR TI Thermal expansion of an E-glass/vinyl ester composite from 4 to 293 K SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE composite; thermal expansion; vinyl ester AB We have measured the thermal expansion of the three principal orthogonal directions of an E-glass/vinyl ester structural composite from liquid helium temperature, 4.2 K, to room temperature, 293 K. The linear thermal expansion at 4.2 K ranged from -0.23 to -0.71%, referenced to zero expansion at 293 K. We fitted the linear thermal expansion data from 4.7 to 293 K with a cubic polynomial for each of the three principal orthogonal directions. RP Slifka, AJ (reprint author), NATL INST STAND & TECHNOL,DIV MAT RELIABIL,BOULDER,CO 80303, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD SEP PY 1997 VL 18 IS 5 BP 1249 EP 1256 DI 10.1007/BF02575259 PG 8 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA XZ992 UT WOS:A1997XZ99200010 ER PT J AU Holcombe, TL Ley, T Gillette, DA AF Holcombe, TL Ley, T Gillette, DA TI Effects of prior precipitation and source area characteristics on threshold wind velocities for blowing dust episodes, Sonoran Desert 1948-78 SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article AB A better understanding of the effects of precipitation and source area on blowing dust in the Sonoran Desert has been sought through the study of 1190 dust episodes occurring during the 1948-78 time period at Blythe, California, and Yuma, Arizona. Threshold mean hourly wind speeds (MHWSs) increase directly with prier precipitation in proportion to the inhibiting effect of the vegetation canopy, which blooms following periods of increased precipitation. Because of the time required for the vegetation canopy to fully develop and the persistence of the vegetation canopy once developed, correlation between the threshold MHWS and precipitation is highest for 4-6-month windows of total precipitation prior to each dust event at both stations. Many dust events associated with unusually low MHWSs are clustered in time. and these events can he correlated with interstate highway construction and soil preparation for new irrigation projects. Since threshold MHWSs for blowing dust lie well below the recorded MHWSs during most dust events at most times, it is possible to predict that mean annual precipitation could in the future increase to about 8 cm per 6 months without significantly reducing the occurrence of blowing dust episodes. On the other hand, increases in future mean annual precipitation to 10-12 cm per 6 months would raise the threshold MHWS to the point that conditions for blowing dust would be substantially reduced. Many of the infrequently occurring periods of elevated precipitation correlate in time with El Nino-Southern Oscillation events, which typically repeat every 2-8 yr. Average MHWSs, and threshold MHWSs far blowing dust, vary with wind direction at Blythe and Yuma. These variations can be related to variations in the susceptibility of upwind source areas in most instances, but in one or more instances this variation may be related to storm type. C1 NOAA,ATMOSPHER RESOURCES LAB,BOULDER,CO 80303. RP Holcombe, TL (reprint author), NOAA,NATL GEOPHYS DATA CTR,325 BROADWAY,BOULDER,CO 80303, USA. NR 10 TC 15 Z9 15 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 SEP PY 1997 VL 36 IS 9 BP 1160 EP 1175 DI 10.1175/1520-0450(1997)036<1160:EOPPAS>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU624 UT WOS:A1997XU62400004 ER PT J AU Moles, A AF Moles, A TI Effect of bacterial kidney disease on saltwater adaptation of coho salmon smolts SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article ID ONCORHYNCHUS-KISUTCH; SALVELINUS-FONTINALIS; ATLANTIC SALMON; RAINBOW-TROUT; BROOK TROUT; SEAWATER; SURVIVAL; FISH; SMOLTIFICATION; TRANSFORMATION AB Coho salmon Oncorhynchus kisutch with clinical infections of bacterial kidney disease (BKD) had poorer survival in the laboratory after 30 d in salt water (50%) than in freshwater (85%). Osmoregulatory ability of infected fish was better after acclimation in 10 parts per thousand salinity water before transfer to 30 parts per thousand salinity water. Infected fish exercised overnight (3.0 body lengths/s) were unable to survive the seawater challenge, whereas uninfected fish similarly exercised survived with the same plasma Na+ levels as unexercised fish. Because BKD is present in most salmonid stocks, stress of seawater transfers should be minimized through acclimation and reduced exertion. RP Moles, A (reprint author), NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,AUKE BAY FISHERIES LAB,11305 GLACIER HIGHWAY,JUNEAU,AK 99801, USA. NR 23 TC 14 Z9 15 U1 1 U2 2 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD SEP PY 1997 VL 9 IS 3 BP 230 EP 233 DI 10.1577/1548-8667(1997)009<0230:EOBKDO>2.3.CO;2 PG 4 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA YD449 UT WOS:A1997YD44900010 ER PT J AU FullerRowell, TJ Codrescu, MV Fejer, BG Borer, W Marcos, F Anderson, DN AF FullerRowell, TJ Codrescu, MV Fejer, BG Borer, W Marcos, F Anderson, DN TI Dynamics of the low-latitude thermosphere: quiet and disturbed conditions SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT 9th International Symposium on Equatorial Aeronomy Including the Middle Atmosphere (ISEA) CY MAR 20-24, 1995 CL BALI, INDONESIA SP Kyoto Univ, Radio Atmospher Sci Ctr, Indonesian Natl Inst Aeronaut & Space, Union RadioSci Int, Sci Comm Solar Terr Phys, Int Assoc Meteorol & Atmospher Sci, Int Assoc Geomagnetism & Aeron, Soc Geomagnetism & Earth Planetary & Space Sci ID F-REGION; ELECTRIC-FIELDS; PLASMA DRIFTS; WINDS; MODEL; TEMPERATURE AB Low-latitude dynamics, electrodynamics, and plasma density structure are closely linked. Dynamically driven electric fields initiate the equatorial ionization anomaly. Between the latitudes of the anomaly crests, steep gradients in ion density span more than three orders of magnitude. Zonal winds accelerate in response to the severe deficit of plasma, and reduced ion drag, at the dip equator. Zonal winds give rise to a vertical polarization field, causing plasma to drift with the neutrals and further diminish ion drag. Signatures of neutral temperature are associated with the winds; cooling appears in the zonal jet itself and there is slight warming on either side. Chemical heating is suggested as the mechanism responsible for the temperature feature, but this has yet to be confirmed. During geomagnetic disturbances, large-scale waves propagate efficiently from the remote high latitude source region. The strength of the waves and the circulation changes depend on local time; the strongest and most penetrating waves arise on the nightside, where they are hindered least by drag from the low ion densities. The rapid arrival of waves to low latitudes may be the cause of the electrodynamic drift that has been observed to follow a rise of geomagnetic activity within four hours. Winds at low latitudes respond to sources from both polar regions. The changes are manifest by the arrival and interaction of a series of waves from high latitudes that propagate well into the opposite hemisphere. Lower altitudes, below the F-region, respond more slowly because propagation speeds are limited in the cooler, dense lower thermosphere. Finally, during solstice, bulges enriched in molecular nitrogen migrate, over a period of a day or so, from their high latitude source to low latitudes. Characteristic negative phases can result, depleting the ionosphere and further feeding electrodynamic change. The timing of low-latitude electrodynamic signatures in response to geomagnetic disturbances is, at least in part, closely connected to global dynamical time scales. Numerical models are used to illustrate the response of the upper atmosphere during quiet and magnetically disturbed conditions, and are used to elucidate the important physical processes. (C) 1995 Elsevier Science Ltd. C1 UTAH STATE UNIV,CTR ATMOSPHER & SPACE SCI,LOGAN,UT 84322. PHILLIPS LAB,HANSCOM AFB,MA 01731. RP FullerRowell, TJ (reprint author), UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,SPACE ENVIRONM LAB,325 BROADWAY,BOULDER,CO 80803, USA. NR 27 TC 62 Z9 63 U1 0 U2 2 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 SEP PY 1997 VL 59 IS 13 BP 1533 EP 1540 DI 10.1016/S1364-6826(96)00154-X PG 8 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA XR095 UT WOS:A1997XR09500007 ER PT J AU Zorn, R Mopsik, FI McKenna, GB Willner, L Richter, D AF Zorn, R Mopsik, FI McKenna, GB Willner, L Richter, D TI Dynamics of polybutadienes with different microstructures .2. Dielectric response and comparisons with rheological behavior SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID KOHLRAUSCH-WILLIAMS-WATTS; DOMAIN HAVRILIAK-NEGAMI; FREQUENCY-DOMAIN; SECONDARY RELAXATION; GLASS-TRANSITION; ALPHA-RELAXATION; POLYMERS; TRANSFORMATION; TEMPERATURE; LIQUIDS AB A series of 1,2-1,4-polybutadienes with varying 1,2 (vinyl) content was investigated using time-domain dielectric spectroscopy, The time range was 10(-5)-300 s, which can be converted by Laplace transform to a frequency range of 10(-3)-6000 Hz. The samples were the same as those used in a previous rheological study from these laboratories. Therefore, a direct comparison of dielectric and mechanical responses was possible. Within experimental uncertainty, the ct relaxation observed by both methods shows the same temperature dependence but there is an offset between the characteristic times of both methods, which increases with increasing vinyl content. This result can be qualitatively understood from the difference of the size of the dipolar groups, viz, cis and vinyl monomeric units, in the context of the DiMarzio-Bishop model. In addition, the question of time-temperature superposition was studied using the dielectric data. In the cases of a vinyl content equal to or greater than 0.53 no deviations from time-temperature superposition-were detected. Only for the sample with the lowest vinyl content (0.07) does the attempt to construct a master curve from the dielectric loss data fail. In this case a fit with a combination of a Havriliak-Negami and a Cole-Cole functions suggests that this deviation from time-temperature superposition is an intrinsic feature of the ct alpha relaxation rather than an effect of its merging with the beta relaxation, The absence of indications for such, a deviation in the rheological study can be explained by the smaller frequency range of the latter. This stresses the necessity of a large dynamic range in experiments aimed at the examination of the time-temperature superposition principle. (C) 1997 American Institute of Physics. C1 NIST, GAITHERSBURG, MD 20899 USA. RP Zorn, R (reprint author), FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, IFF, POSTFACH 1913, D-52425 JULICH, GERMANY. RI Richter, Dieter/H-3701-2013; McKenna, Gregory/O-1134-2013 OI Richter, Dieter/0000-0003-0719-8470; McKenna, Gregory/0000-0002-5676-9930 NR 34 TC 49 Z9 49 U1 2 U2 11 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD SEP 1 PY 1997 VL 107 IS 9 BP 3645 EP 3655 DI 10.1063/1.474722 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XU115 UT WOS:A1997XU11500033 ER PT J AU Tomaszkiewicz, I Hope, GA OHare, PAG AF Tomaszkiewicz, I Hope, GA OHare, PAG TI A fluorine bomb calorimetric determination of the standard molar enthalpy of formation of silicon disulfide SiS2(cr) at the temperature 298.15 K. Enthalpies of dissociation of Si-S bonds SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article DE silicon disulfide; calorimetry; thermochemistry; enthalpy of formation; bond dissociation enthalpies ID THERMODYNAMIC PROPERTIES; INORGANIC CHALCOGENIDES; COMBUSTION CALORIMETRY; THERMOCHEMISTRY; GERMANIUM; SULFUR; SPECTROSCOPY; TELLURIUM; SELENIUM AB A synthesis of high-purity silicon disulfide SiS2 is described, and the F.t.-Raman spectrum of the solid is reported for the first time. The standard massic energy of reaction of SiS2(cr) with fluorine was measured in a bomb calorimeter. The combustion reaction was shown to proceed as follows: SiS2(cr) + 8F(2)(g) = SiF4(g) + 2SF(6)(g). The derived standard molar enthalpy of formation is: Delta(f)H(m)(o)(SiS2,cr, 298.15 K) = -(254.6 +/- 2.9) kJ . mol(-1). This value differs significantly From those determined by solution-reaction calorimetry, but is in fair agreement with results obtained by means of third-law treatments of high-temperature equilibria. The ratio of molar enthalpies of dissociation of the ''first'' and ''second'' bonds in SiS2(g), k = D-m(o)(S-SiS)/D-m(o)(SiS) = (0.57 +/- 0.03), is similar to ks reported previously for SiO2 and SiSe2. (C) 1997 Academic Press Limited. C1 NIST,CHEM SCI & TECHNOL LAB,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. POLISH ACAD SCI,INST PHYS CHEM,WARSAW,POLAND. GRIFFITH UNIV,NATHAN,QLD 4111,AUSTRALIA. RI Hope, Gregory/A-7556-2008 OI Hope, Gregory/0000-0003-2694-3456 NR 53 TC 7 Z9 7 U1 2 U2 10 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0021-9614 J9 J CHEM THERMODYN JI J. Chem. Thermodyn. PD SEP PY 1997 VL 29 IS 9 BP 1031 EP 1045 DI 10.1006/jcht.1997.0221 PG 15 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA XW778 UT WOS:A1997XW77800008 ER PT J AU Smith, TM Ropelewski, CF AF Smith, TM Ropelewski, CF TI Quantifying southern oscillation-precipitation relationships from an atmospheric GCM SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURES; SCALE PRECIPITATION; RAINFALL; INDIA AB This paper is an extension of a study by C. Ropelewski and M. Halpert, which examines observed precipitation relationships with the Southern Oscillation. Here, the authors repeat their analysis using atmospheric general circulation model precipitation from the average of a 13-run ensemble. The GCM is the atmospheric component of the coupled model used for seasonal prediction at the National Centers for Environmental Prediction, except that in this study, the observed sea surface temperatures were specified for the ensemble runs. Results are compared and contrasted with the observed Southern Oscillation-related precipitation behavior. These comparisons show that the multiple ensemble simulations compare favorably to the observations for most areas in the Tropics and subtropics. However, outside of the deep Tropics, the model simulations show large shifts or biases in the location of the Southern Oscillation-related anomalies. In particular, anomalies shown by the observations to occur in the southeastern United States are shifted westward in the simulation. RP Smith, TM (reprint author), NOAA,CLIMATE PREDICT CTR,ANAL BRANCH,NATL CTR ENVIRONM PREDICT,NWS,WORLD WEATHER BLDG,CAMP SPRINGS,MD 20746, USA. RI Smith, Thomas M./F-5626-2010 OI Smith, Thomas M./0000-0001-7469-7849 NR 15 TC 15 Z9 15 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD SEP PY 1997 VL 10 IS 9 BP 2277 EP 2284 DI 10.1175/1520-0442(1997)010<2277:QSOPRF>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX482 UT WOS:A1997XX48200010 ER PT J AU Barnett, TP Arpe, K Bengtsson, L Ji, M Kumar, A AF Barnett, TP Arpe, K Bengtsson, L Ji, M Kumar, A TI Potential predictability and AMIP implications of midlatitude climate variability in two general circulation models SO JOURNAL OF CLIMATE LA English DT Article ID NATIONAL-METEOROLOGICAL-CENTER; FORECAST SYSTEM; PREDICTIONS AB Ensembles of extended Atmospheric Model Intercomparison Project (AMIP) runs from the general circulation models of the National Centers for Environmental Prediction (formerly the National Meteorological Center) and the Max-Planck Institute (Hamburg, Germany) are used to estimate the potential predictability (PP) of an index of the Pacific-North America (PNA) mode of climate change. The PP of this pattern in ''perfect'' prediction experiments is 20%-25% of the index's variance. The models, particularly that from MPI, capture virtually all of this variance in their hindcasts of the winter PNA for the period 1970-93. The high levels of internally generated model noise in the PNA simulations reconfirm the need for an ensemble averaging approach to climate prediction. This means that the forecasts ought to be expressed in a probabilistic manner. It is shown that the models' skills are higher by about 50% during strong SST events in the tropical Pacific, so the probabilistic forecasts need to be conditional on the tropical SST. Taken together with earlier studies, the present results suggest that the original set of AMIP integrations (single IO-yr runs) is not adequate to reliably test the participating models' simulations of interannual climate variability in the midlatitudes. C1 MAX PLANCK INST METEOROL,HAMBURG,GERMANY. NOAA,NCEP,CLIMATE MODELING BRANCH,WASHINGTON,DC. RP Barnett, TP (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,DIV CLIMATE RES,LA JOLLA,CA 92093, USA. NR 17 TC 26 Z9 27 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD SEP PY 1997 VL 10 IS 9 BP 2321 EP 2329 DI 10.1175/1520-0442(1997)010<2321:PPAAIO>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX482 UT WOS:A1997XX48200013 ER PT J AU Parson, LE Lillycrop, WJ Klein, CJ Ives, RCP Orlando, SP AF Parson, LE Lillycrop, WJ Klein, CJ Ives, RCP Orlando, SP TI Use of lidar technology for collecting shallow water bathymetry of Florida Bay SO JOURNAL OF COASTAL RESEARCH LA English DT Article DE lidar survey; bathymetry; hydrographic survey; shallow water estuary AB Due to an accelerated decline in water quality, Florida Bay is the focus of an inter-agency restoration program involving a modeling effort to define water circulation patterns both internally and between its surrounding waters. Models such as these require adequate resolution of the Bay's morphologic features which are characterized by extensive shallow water networks of mud banks, cuts, and basins. However, the information necessary to resolve the complex bathymetry does not exist on current NOAA navigation charts. The Bay's expansive shallow water characteristics renders much of it inaccessible by conventional waterborne survey methods. Obtaining this information requires an alternative survey technology capable of covering large shallow water areas and producing high resolution bathymetric data. During the spring of 1994 the SHOALS (Scanning Hydrographic Operational Airborne Lidar Survey) system was employed by NOAA to test its ability to resolve the complex shallow water bathymetry for a test area in central Florida Bay. Approximately 13 km(2) of area was surveyed with a total surveying time of 12 hours. The data set presented here demonstrates that airborne lidar bathymetric technology such as SHOALS can be a valuable and cost effective tool for surveying large shallow water areas, without damage to the environment, that are otherwise inaccessible by conventional methods. C1 NOAA,OFF OCEAN RESOURCES CONSERVAT & ASSESSMENT,SILVER SPRING,MD 20910. RP Parson, LE (reprint author), USA,ENGINEER WATERWAYS EXPT STN,COASTAL ENGN RES CTR,VICKSBURG,MS 39180, USA. NR 7 TC 12 Z9 12 U1 1 U2 4 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 FAL PY 1997 VL 13 IS 4 BP 1173 EP 1180 PG 8 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA XZ999 UT WOS:A1997XZ99900019 ER PT J AU Gaigalas, AK Niaura, G AF Gaigalas, AK Niaura, G TI Measurement of electron transfer rates between adsorbed azurin and a gold electrode modified with a hexanethiol layer SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE adsorption; azurin; cyclic voltammetry; electron transfer rate; electroreflectance; hexanethiol; SERRS ID BLUE COPPER PROTEINS; CYTOCHROME-C; HYDROPHOBIC PATCH; MARCUS THEORY; ELECTROREFLECTANCE; SURFACE; RESOLUTION AB In this work we report the application of electroreflectance (ER) spectroscopy for the study of the redox reaction of the nonheme protein azurin, Azurin was irreversibly adsorbed on a polycrystalline gold surface modified with a hexanethiol layer. Surface-enhanced resonant Raman spectroscopy (SERRS) demonstrated that the immobilized azurin's copper site remained intact upon adsorption and that it underwent reversible reduction-oxidation, Cyclic voltammetry (CV) data showed that the peak current of the oxidation (or reduction) wave depended linearly on the sweep rate as appropriate for an immobilized species. The formal potential of the adsorbed azurin was 95 +/- 8 mV vs Ag/AgCl electrode, nearly identical to the earlier observed value of the native azurin in solution. All measurements were analyzed in the context of Marcus theory of electron transfer, The separation of the reduction-oxidation peaks in the CV data gave an estimate of the electron transfer (ET) rate in the range from 4 to 12 s(-1). ER, with light of wavelength of 640 nm, yielded a strong signal at the same potential as the midpotential determined in CV, The frequency dependence of the ER response was consistent with an ET rate of 150 to 200 s(-1). Electrochemical impedance measurements indicated an ET rate of the order of 300 s(-1). The disparity between the ET rates measured with CV and ER suggests that ET may not be a single-step process. The results also point to the importance of hydrophobic interactions in adsorption and redox transformations of azurin. (C) 1997 Academic Press. RP Gaigalas, AK (reprint author), NIST,DIV BIOTECHNOL,222-A353,GAITHERSBURG,MD 20899, USA. NR 33 TC 59 Z9 59 U1 1 U2 5 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD SEP 1 PY 1997 VL 193 IS 1 BP 60 EP 70 DI 10.1006/jcis.1997.5034 PG 11 WC Chemistry, Physical SC Chemistry GA XZ250 UT WOS:A1997XZ25000008 ER PT J AU Simiu, E Franaszek, M AF Simiu, E Franaszek, M TI Melnikov-based open-loop control of escape for a class of nonlinear systems SO JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT Design Engineering Technical Conference, at the American-Society-of-Mechanical-Engineers Meeting CY 1995 CL BOSTON, MA SP Amer Soc Mech Engineers ID CHAOS; NOISE AB The performance of certain nonlinear stochastic systems is deemed acceptable if during a specified time interval, the systems have sufficiently low probabilities of escape from a preferred region of phase space. We propose an open-loop control method for reducing these probabilities. The method is applicable to stochastic systems whose dissipation-and excitation-free counterparts have homoclinic or heteroclinic orbits. The Melnikov relative scale factors are system properties containing information. on the frequencies of the random forcing spectral components that are most effective in inducing escapes. Numerical simulations show that substantial (advantages can be achieved in some cases by designing control systems that rake into account the information contained in the Melnikov scale factors. RP Simiu, E (reprint author), NIST,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899, USA. NR 13 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 0022-0434 J9 J DYN SYST-T ASME JI J. Dyn. Syst. Meas. Control-Trans. ASME PD SEP PY 1997 VL 119 IS 3 BP 590 EP 594 DI 10.1115/1.2801302 PG 5 WC Automation & Control Systems; Instruments & Instrumentation SC Automation & Control Systems; Instruments & Instrumentation GA XZ558 UT WOS:A1997XZ55800036 ER PT J AU Keller, RR Nucci, JA Field, DP AF Keller, RR Nucci, JA Field, DP TI Local textures and grain boundaries in voided copper interconnects SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT Symposium on Evolution and Advanced Characterization of Thin Film Microstructures, at the TMS 1997 Annual Meeting CY FEB 09-13, 1997 CL ORLANDO, FL SP TMS DE copper; grain boundary; texture; thin films ID AL METALLIZATION; LINES; MICROSTRUCTURE; ORIENTATION AB We have characterized grain boundary structures and local textures in stress voided copper lines. Grain boundary misorientations as well as the tilt and twist character of boundaries were measured using electron backscatter diffraction in the scanning electron microscope in conjunction with focused ion beam images. We have summarized data for a number of boundaries immediately adjacent to voids and made comparisons to boundaries from regions that remained intact. These data were acquired from the same lines, and so represent measurements from material with identical histories. Significant local variations in microstructure were observed. Local [111] textures of grains near voids were of lower strength than those away from voids. Grain boundaries intersecting voids were of higher angle character and had significant twist components. These results suggest that local regions associated with more favorable kinetics are more susceptible to void formation and growth. C1 CORNELL UNIV,SCH ELECT ENGN,ITHACA,NY 14853. TEXSEM LABS INC,PROVO,UT 84604. RP Keller, RR (reprint author), NATL INST STAND & TECHNOL,DIV MAT RELIABIL,325 BROADWAY,BOULDER,CO 80303, USA. RI Keller, Robert/I-9014-2012; Field, David/D-5216-2012 OI Field, David/0000-0001-9415-0795 NR 23 TC 20 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 SEP PY 1997 VL 26 IS 9 BP 996 EP 1001 DI 10.1007/s11664-997-0236-z PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA XW113 UT WOS:A1997XW11300007 ER PT J AU Helser, TE Almeida, FP AF Helser, TE Almeida, FP TI Density-dependent growth and sexual maturity of silver hake in the north-west Atlantic SO JOURNAL OF FISH BIOLOGY LA English DT Article DE Merluccius bilinearis; life-history; reproductive strategy; compensatory response ID GADUS-MORHUA; AGE; MATURATION; FISHES; SHELF; OCEAN; SIZE; COD AB Stock abundance was the most important predictor of sexual maturation of age 2 and 3 silver hake in the north-west Atlantic between 1973-1990. Growth at ages 1 and 2 in the southern stock was significantly and negatively correlated with stock abundance (r(2)>0.56, P<0.01). Sexual maturity may be mediated through competition and growth during the first and second years of life. In the northern stock, growth and stock abundance was not significantly correlated (P>0.05). Here, increased sexual maturity at ages 2 and 3 during 1973-1990 may have occurred without increased somatic growth, already near its maximum, due to the relatively cooler water temperatures of the Gulf of Maine. Logistic regression models indicated that maturation is dependent on age, stock density and an age-density interaction. (C) 1997 The Fisheries Society of the British Isles. C1 NE FISHERIES SCI CTR,WOODS HOLE,MA 02543. NR 52 TC 33 Z9 33 U1 1 U2 4 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD SEP PY 1997 VL 51 IS 3 BP 607 EP 623 DI 10.1111/j.1095-8649.1997.tb01516.x PG 17 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XW298 UT WOS:A1997XW29800014 ER PT J AU Benzinger, EA Emerek, EA Grigsby, NL Duewer, DL Lovekamp, ML Deadman, H Thompson, JL Sallee, PJ Riech, AK AF Benzinger, EA Emerek, EA Grigsby, NL Duewer, DL Lovekamp, ML Deadman, H Thompson, JL Sallee, PJ Riech, AK TI Products of partial digestion with Hae III .1. Characterization, casework experience and confirmation of the theory of three-, four- and five-banded RFLP pattern origins using partial digestion SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; band shift; band sizing; DNA typing; gel electrophoresis; restriction fragment length polymorphism; variable number tandem repeat; partial digestion ID FORENSIC DNA ANALYSIS; DEOXYRIBONUCLEIC-ACID DNA; PROFILING MEASUREMENTS; VARIABLE NUMBER; FRAGMENT; POLYMORPHISM; MINISATELLITES; D10S28; VNTR AB The sizes of Hae III partial digestion products at D1S7, D2S44, D4S139, D5S110, D10528, and D17S26 were evaluated in experimentally generated partial digestions of liquid blood DNA. The partial digestion products were highly predictable, suggesting a very high level of sequence conservation in regions flanking variable number tandem repeat (VNTR) blocks. Partial digestion bands associated with three-or-more-banded patterns were also characterized. Partial digestion of three-banded patterns can be used to determine whether the extra bands arise due to internal Hae III sites in the VNTR block and to identify hidden three-banded patterns. Partial digestion products from forensic casework also conformed to size expectations. Presumed partial digestion bands from 27 forensic samples were compared to the experimentally generated data. The causes of partial digestion are examined and recommendations for interpreting forensic DNA evidence exhibiting partial digestion products are given. C1 ILLINOIS STATE POLICE,SPRINGFIELD,IL. NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. FED BUR INVEST,DNA UNIT,WASHINGTON,DC. RI Duewer, David/B-7410-2008 NR 39 TC 3 Z9 4 U1 0 U2 1 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD SEP PY 1997 VL 42 IS 5 BP 850 EP 863 PG 14 WC Medicine, Legal SC Legal Medicine GA XW332 UT WOS:A1997XW33200015 PM 9304832 ER PT J AU Duewer, DL Benzinger, EA AF Duewer, DL Benzinger, EA TI Products of partial digestion with Hae III .2. Quantification SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; band shift; band sizing; DNA typing; gel electrophoresis; restriction fragment length polymorphism; variable number of tandem repeat ID DNA PROFILING MEASUREMENTS; MEASUREMENT ERRORS; FRAGMENT-LENGTH AB The base pair size of the excess DNA in the smallest three partial digestion bands for the variable number of tandem repeat loci D1S7, D2S44, D4S139, D52110, D10S28, and D17S26 has been quantitatively evaluated using data obtained from intentional partial digestion of liquid blood DNA. Restriction fragment length polymorphism (RFLP) measurement characteristics specific to the performing laboratory were evaluated from that laboratory's historical K562 cell line control data. The expected size of the excess DNA is estimated as the weighted mean of the differences between the measured size of the partially digested bands and the fully digested band, with the weights predicted using knowledge of RFLP measurement characteristics. Confidence limits ate developed for evaluating whether the size differences among a set of RFLP band multiplets observed in pristine samples are consistent with those expected from partial digestion. The base pair size of excess DNA for partials observed in evidentiary samples appears to be somewhat less than that from pristine samples. C1 NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,DIV ANALYT CHEM,GAITHERSBURG,MD 20899. ILLINOIS STATE POLICE,SPRINGFIELD,IL. RI Duewer, David/B-7410-2008 NR 14 TC 4 Z9 4 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD SEP PY 1997 VL 42 IS 5 BP 864 EP 872 PG 9 WC Medicine, Legal SC Legal Medicine GA XW332 UT WOS:A1997XW33200016 PM 9304833 ER PT J AU Kline, MC Duewer, DL Newall, P Redman, JW Reeder, DJ Richard, M AF Kline, MC Duewer, DL Newall, P Redman, JW Reeder, DJ Richard, M TI Interlaboratory evaluation of short tandem repeat triplex CTT SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; allele sizing; CTTv CSF1PO; TPOX; TH01; vWA; DNA typing; gel electrophoresis; interlaboratory comparison; polymerase chain reaction ID ACCURATE AB An interlaboratory comparison of typing results for Short Tandem Repeats (STRs) at the GenBank loci HUMCSF1PO, HUMTPOX, HUMTH01, and HUMVWFA31 using the ''CTT triplex'' and ''CTTv quadruplex'' has been evaluated. These STRs all have a nominal four basepair (bp) repeat. Seven different samples were distributed to 41 laboratories. The 34 laboratories that returned results used a wide variety of analytical systems. Comparable results were obtained for all samples at all loci when results were reported as an allelic name. Raw sizing results obtained from internal-lane sizing standards differed by nearly five bp at some loci. Many different factors contribute to this observed sizing variability, including choice of sizing standards and matrix composition. Although sizing results can be made more comparable by locus-specific offsets or calibration to a comprehensive set of alleles at each locus, samples typed to the allelic name can now be validly compared regardless of analytical method. Interlaboratory comparison of raw allelic size remains problematic. C1 NIST,CHEM SCI & TECHNOL LAB,DIV ANALYT CHEM,GAITHERSBURG,MD 20899. CTR FORENS SCI,BIOL SECT DNA,TORONTO,ON M7A 2G8,CANADA. RP Kline, MC (reprint author), NIST,CHEM SCI & TECHNOL LAB,DIV BIOTECHNOL,GAITHERSBURG,MD 20899, USA. RI Duewer, David/B-7410-2008 NR 10 TC 19 Z9 20 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD SEP PY 1997 VL 42 IS 5 BP 897 EP 906 PG 10 WC Medicine, Legal SC Legal Medicine GA XW332 UT WOS:A1997XW33200022 PM 9304839 ER PT J AU Wagner, CA Klokocnik, J Kostelecky, J AF Wagner, CA Klokocnik, J Kostelecky, J TI Dual-satellite crossover latitude-lumped coefficients, their use in geodesy and oceanography SO JOURNAL OF GEODESY LA English DT Article DE crossover satellite altimetry; latitude-lumped coefficients; coordinate systems ID GEOPOTENTIAL ERRORS; TOPEX POSEIDON; ALTIMETRY; ERS-1; ACCURACY; GEOSAT AB Latitude-lumped coefficients (LLC) are defined, representing geopotential-orbit variations for dual-satellite crossovers (DSC). Formulae are derived for their standard errors from the covariances of geopotential held models. Numerical examples are presented for pairs of the altimeter-bearing satellites TOPEX/Poseidon, ERS 1, and Geosat, using the error matrices of recent gravity models. The DSC, connecting separate missions, will play an increasingly important role in oceanography spanning decades only when its nonoceanographic signals are thoroughly understood. In general, the content of even the long-term averaged DSC is more complex then their single satellite crossover (SSC) counterpart. The LLC, as the spatial spectra for the geopotential-caused crossover effects, discriminate these source-differences sharply. Thus, the zero-order LLC in DSC data contains zonal gravity information not present in SSC data. In addition, zero-and first-order LLC of DSC data can reveal a geocenter discrepancy between the orbit tracking of the separate satellite missions. For example, DSC analysis from orbits computed with JGM 2 show that the y-axis of the geocenter for Geosat in 1986-1988 is shifted with respect to T/P by 6-9 cm towards the eastern Pacific. Also, where the time-gap is necessarily large (as between, say, Geosat and T/P missions) oceanographic (sea-level) differences in DSC may corrupt the geopotential interpretation of the data. Most importantly, as we illustrate, media delays for the altimeter (from the ionosphere, wet troposphere and sea-state bias) are more likely sources of contamination across two missions than in SSC analyses. Again, the LLC of zero order best shows this contrast. Using the higher-order LLC of DSC for both Geosat-T/P and ERS 1-T/P as likely representation of geopotential-only error, we show by comparison with the predicted standard errors of JGM 2 that the latter's previously calibrated covariance matrix is generally valid. C1 ACAD SCI CZECH REPUBL,INST ASTRON,CZ-25165 ONDREJOV,CZECH REPUBLIC. NOAA,NOS,OFF OCEAN & EARTH SCI,SILVER SPRING,MD 20910. RES INST GEODESY TOPOG & CARTOG,CZ-25066 ZDIBY 98,CZECH REPUBLIC. RI Klokocnik, Jaroslav/G-9025-2014 NR 24 TC 12 Z9 12 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0949-7714 J9 J GEODESY JI J. Geodesy PD SEP PY 1997 VL 71 IS 10 BP 603 EP 616 DI 10.1007/s001900050128 PG 14 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA XY466 UT WOS:A1997XY46600002 ER PT J AU Codrescu, MV FullerRowell, TJ Roble, RG Evans, DS AF Codrescu, MV FullerRowell, TJ Roble, RG Evans, DS TI Medium energy particle precipitation influences on the mesosphere and lower thermosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID GENERAL-CIRCULATION MODEL; SOLAR PROTON EVENT; MIDDLE ATMOSPHERE; OZONE DEPLETION; JULY 13; ELECTRODYNAMICS; CONDUCTIVITIES; CONVECTION; ELECTRONS AB Data accumulated for more than a solar cycle by the TIROS/NOAA polar orbiting satellites are used to extract patterns of particle precipitation in several medium energy bands for varying geomagnetic conditions. While the atmospheric effects of amoral particles measured by these satellites (300 eV-20 keV) have been widely studied, the effects of medium energy (30 keV-2.5 MeV) particles have received less attention; in this paper we present average particle precipitation patterns for medium energy protons and electrons as a function of geomagnetic activity. A magnetic coordinate system is used to bin data at high latitudes to produce patterns that are then used as additional inputs to the National Center for Atmospheric Research thermosphere ionosphere mesosphere electrodynamic general circulation model (TIME-GCM) to study the effects of medium energy particles on the mesosphere and lower thermosphere. Model results obtained with these additional inputs are used to assess the significance of medium energy particles on the composition and dynamics of the region. Zonally averaged model results from the run that includes the medium energy particles show significant increases in, n(e), HOX, NO2, and NO and a 27 percent decrease in O-3 between 70 and 80 km in the polar regions when compared to a similar run without the particles. The temperature and wind differences are small. C1 NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,BOULDER,CO 80307. NCAR,HIGH ALTITUDE OBSERV,BOULDER,CO. RP Codrescu, MV (reprint author), NOAA,SPACE ENVIRONM CTR,R-E-SE,325 BROADWAY,BOULDER,CO 80303, USA. NR 24 TC 72 Z9 72 U1 0 U2 3 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 SEP 1 PY 1997 VL 102 IS A9 BP 19977 EP 19987 DI 10.1029/97JA01728 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XU866 UT WOS:A1997XU86600023 ER PT J AU Goni, GJ Garzoli, SL Roubicek, AJ Olson, DB Brown, OB AF Goni, GJ Garzoli, SL Roubicek, AJ Olson, DB Brown, OB TI Agulhas ring dynamics from TOPEX/POSEIDON satellite altimeter data SO JOURNAL OF MARINE RESEARCH LA English DT Article ID SOUTHEAST ATLANTIC-OCEAN; GULF-STREAM RINGS; CURRENT SYSTEM; EDDY; RETROFLECTION; EVOLUTION; KUROSHIO; VELOCITY; MODEL AB The transfer of warm water from the Indian Ocean into the South Atlantic subtropical gyre takes place in the form of rings and filaments formed when the Agulhas Current retroflects south of Africa between 15 and 25E. A survey of the rings formed from September 1992 until December 1995 in the Retroflection region was carried out using TOPEX/POSEIDON altimeter data. A two-layer model was used to estimate the upper layer thickness from the altimeter-derived sea-surface height anomaly data. An objective analysis scheme was used to construct a map of upper layer thickness every ten days. Seventeen rings and their trajectories were identified using these maps. The shedding of rings from the Agulhas Current was neither continuous nor periodic, and for long periods there is no formation of rings. Several rings remained in the region for more than a year and, at any given time, 2 to 6 rings coexisted in the region east of the Walvis Ridge. The results showed that the number of rings translating simultaneously in this region is larger during the first half of each year. The upper layer transport of the Agulhas Current in the Retroflection region was computed and a close association between high variations in transport and ring shedding was found. Rings translated WNW at translation speeds ranging from 5 to 16 km day(-1) following formation. The values of available potential energy computed for the rings place them among the most energetic rings observed in the world oceans, with values of up to 70 x 10(15) J. Transport computations indicate that each ring contributes in the average approximately 1 Sv of Agulhas Current waters to the Benguela Current. C1 NOAA, ATLANTIC OCEANOG & METEOROL LAB, MIAMI, FL 33149 USA. UNIV MIAMI, ROSENSTIEL SCH MARINE & ATMOSPHER SCI, COOPERAT INST MARINE & ATMOSPHER STUDIES, MIAMI, FL 33149 USA. RP UNIV MIAMI, ROSENSTIEL SCH MARINE & ATMOSPHER SCI, DIV METEOROL & PHYS OCEANOG, MIAMI, FL 33149 USA. RI Garzoli, Silvia/A-3556-2010; Brown, Otis/C-7188-2015; Goni, Gustavo/D-2017-2012; OI Garzoli, Silvia/0000-0003-3553-2253; Brown, Otis/0000-0003-3111-1507; Goni, Gustavo/0000-0001-7093-3170; Olson, Donald/0000-0001-7180-5672 NR 38 TC 77 Z9 77 U1 0 U2 4 PU SEARS FOUNDATION MARINE RESEARCH PI NEW HAVEN PA YALE UNIV, KLINE GEOLOGY LAB, 210 WHITNEY AVENUE, NEW HAVEN, CT 06520-8109 USA SN 0022-2402 EI 1543-9542 J9 J MAR RES JI J. Mar. Res. PD SEP PY 1997 VL 55 IS 5 BP 861 EP 883 DI 10.1357/0022240973224175 PG 23 WC Oceanography SC Oceanography GA YH097 UT WOS:A1997YH09700003 ER PT J AU Wei, LH White, GS AF Wei, LH White, GS TI Thermal diffusivity maps: Case studies in ceramics SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID BONDED SILICON-NITRIDE; SIC-FIBER; MATRIX COMPOSITES; CONTACT DAMAGE; FGM RESEARCH; CONDUCTIVITY; BARRIER; MICROSTRUCTURE; ALUMINA; CRACKS AB A new methodology for mapping thermal diffusivity using a photothermal deflection method is introduced. Two case studies are made: fiber-reinforced composite structures and contact damage zones in alumina. In the former, characterization of thermal microstructural features is demonstrated; in the latter, microcrack density is quantified. Experimental data are analyzed and compared with literature results. Advantages and limitations of the technique are discussed. RP NATL INST STAND & TECHNOL, DIV CERAM, GAITHERSBURG, MD 20899 USA. NR 39 TC 4 Z9 4 U1 1 U2 4 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD SEP PY 1997 VL 12 IS 9 BP 2381 EP 2387 DI 10.1557/JMR.1997.0315 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA XY510 UT WOS:A1997XY51000020 ER PT J AU Lovas, FJ Hartwig, H AF Lovas, FJ Hartwig, H TI The microwave spectrum of the methanol dimer for K = 0 and 1 states SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID INTERNAL-ROTATION BARRIER; TUNNELING SPLITTINGS; COMPLEXES; AR AB The rotational spectrum of (CH3OH)(2) has been observed in the 8 to 24 GHz region with a pulsed-beam Fabry-Perot cavity Fourier-transform microwave spectrometer. Previously we demonstrated that each transition of the a-type R(J), K-a = 0 is split into 15 states of the 16 theoretically expected states by tunneling motions. Here we show that the K = 1 states are split into the 16 expected states through the assignment of the K-a = 1 a-type transitions and Delta K-a = 1 b-type transitions. The internal-rotation analysis of the two inequivalent methyl groups presented here was guided by the previous experimental observations and theory for multidimensional tunneling, which predicts 16 tunneling components for each R(J) transition from 25 distinct tunneling motions. The effective barrier to internal rotation for the donor methyl group of (CH3OH)(2) is V-3 = 183.0 cm(-1), and is one-half of the value for the methanol monomer (370 cm(-1)), while the barrier to internal rotation of the acceptor methyl group is 120 cm(-1), one-third of the methanol monomer. The structure of the methanol dimer complex is similar to that of water dimer with a hydrogen bond distance of 1.96(2) Angstrom and tilt of the acceptor methanol of 77(2)degrees from the O-H-O axis (one standard deviation uncertainty). This structure shows good agreement with the angular orientation of the methyl groups derived in the internal-rotation analysis. (C) 1997 Academic Press. C1 CHRISTIAN ALBRECHTS UNIV KIEL,INST PHYS CHEM,D-24098 KIEL,GERMANY. RP Lovas, FJ (reprint author), NATL INST STAND & TECHNOL,OPT TECHNOL DIV,GAITHERSBURG,MD 20899, USA. NR 20 TC 24 Z9 24 U1 1 U2 8 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 SEP PY 1997 VL 185 IS 1 BP 98 EP 109 DI 10.1006/jmsp.1997.7371 PG 12 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA YD830 UT WOS:A1997YD83000013 ER PT J AU Xu, LH Wang, XL Cronin, TJ Perry, DS Fraser, GT Pine, AS AF Xu, LH Wang, XL Cronin, TJ Perry, DS Fraser, GT Pine, AS TI Sub-Doppler infrared spectra and torsion-rotation energy manifold of methanol in the CH-Stretch fundamental region SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID GASEOUS METHYL-ALCOHOL; DIODE-LASER SPECTRA; HIGH-RESOLUTION; ADDITIONAL MEASUREMENTS; FOURIER SPECTRUM; GLOBAL FIT; CH3OH; TRANSITIONS; MICROWAVE; STATE AB The infrared spectrum of jet-cooled methanol in the CH-stretch fundamental region has been investigated by two sub-Doppler laser techniques: optothermally detected molecular-beam electric resonance and direct-absorption slit-jet spectroscopy. With the aid of microwave-infrared double resonance and ground state combination differences, 27 subbands in the frequency range 2967 to 3027 cm(-1) have been assigned to the nu(2) fundamental. Perturbation systems in the K' = 0 E, -1 E, and -2 E symmetry subbands have been analyzed to yield matrix elements of 0.013, 0.041, and 0.75 cm(-1), respectively. The A-E torsional tunneling splitting for J = 0 of the nu(2) vibration of -3.26 cm(-1) is of opposite sign and a factor of three smaller in magnitude than the ground state value of +9.12 cm(-1). (C) 1997 Academic Press. C1 UNIV AKRON,DEPT CHEM,AKRON,OH 44325. NATL INST STAND & TECHNOL,OPT TECHNOL DIV,GAITHERSBURG,MD 20899. RP Xu, LH (reprint author), UNIV NEW BRUNSWICK,DEPT PHYS SCI,ST JOHNS,NB E2L 4L5,CANADA. RI Xu, Li-Hong/J-5095-2015 NR 53 TC 66 Z9 67 U1 0 U2 9 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 SEP PY 1997 VL 185 IS 1 BP 158 EP 172 DI 10.1006/jmsp.1997.7367 PG 15 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA YD830 UT WOS:A1997YD83000021 ER PT J AU Kramida, A Martin, WC AF Kramida, A Martin, WC TI A compilation of energy levels and wavelengths for the spectrum of neutral beryllium (Be I) SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE atomic energy levels; atomic spectra; atomic wavelengths; atomic wavenumbers; autoionization; beryllium; energy-level classifications; electron configurations; forbidden lines; infrared wavelengths; infrared wavenumbers; ionization potential; photoionization resonances; ultraviolet absorption; ultraviolet wavelengths ID BE-I; STATES; SPECTROSCOPY; MG AB In this compilation we have used data from some 20 references, only two of which were available to C. E. Moore for her 1949 Atomic Energy Levels tables. The new compilation thus includes significant revisions, extensions, and improvements of the earlier data for configurations of the types 1s(2)2snl and 1s(2)2pnl and also extends the energy range to higher configurations, including those involving Is electron excitation. The observed wavelengths for some 200 lines are given with their energy-level classifications. The wavelength measurements, which extend from 89 to 31 780 Angstrom, were obtained from emission spectra of hollow-cathode and are discharges, beam-foil spectra, and far-ultraviolet photoabsorption spectra. In addition to the energy levels derived from these spectra, we include levels obtained from multiphoton resonance-ionization mass spectrometry and projectile-Auger spectroscopy. We have evaluated a number of levels by using series formulas and/or theoretical results; these levels are more accurate than values derived from available wavelength measurements. Wavelengths calculated from energy-level differences are given for all lines; these ''Ritz'' wavelengths are more accurate than the observed values wherever the differences are significant. (C) 1997 American Institute of Physics and American Chemical Society. C1 NIST,PHYS LAB,GAITHERSBURG,MD 20899. RP Kramida, A (reprint author), RUSSIAN ACAD SCI,INST SPECT,TROITSK 142092,MOSCOW REGION,RUSSIA. OI Kramida, Alexander/0000-0002-0788-8087 NR 35 TC 48 Z9 48 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD SEP-OCT PY 1997 VL 26 IS 5 BP 1185 EP 1194 PG 10 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA YA867 UT WOS:A1997YA86700001 ER PT J AU Munro, RG AF Munro, RG TI Material properties of a sintered alpha-SiC SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE evaluated data; mechanical properties; physical properties; silicon carbide; thermal properties ID SILICON-CARBIDE; HIGH-TEMPERATURE; STRENGTH DEGRADATION; SLIDING FRICTION; CERAMICS; WEAR; CORROSION; OXIDATION; FUTURE AB A self-consistent, single-valued representation of the major physical, mechanical, and thermal properties of a sintered alpha-SiC is presented. This comprehensive set of properties is achieved by focusing on a narrowly defined material specification in which boron and carbon are used as sintering aids to produce a dense ceramic (greater than or equal to 98% of the theoretical maximum density) with a grain size of (6+/-2) mu m. Such a representation is highly desirable in applications of concurrent engineering practices and for the increasing use of electronic processing of product specifications. (C) 1997 American Institute of Physics and American Chemical Society. RP Munro, RG (reprint author), NIST,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 49 TC 157 Z9 159 U1 2 U2 46 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD SEP-OCT PY 1997 VL 26 IS 5 BP 1195 EP 1203 PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA YA867 UT WOS:A1997YA86700002 ER PT J AU Christophorou, LG Olthoff, JK Wang, YC AF Christophorou, LG Olthoff, JK Wang, YC TI Electron interactions with CCl2F2 SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Review DE attachment; CCl2F2; cross sections; dichlorodifluoromethane; dissociation; electron interactions; fragments; ionization; scattering; transport ID ATTACHMENT CROSS-SECTIONS; SMALL ORGANIC-MOLECULES; NEGATIVE-ION FORMATION; GAS-MIXTURES; ENERGY-RANGE; DISSOCIATIVE ATTACHMENT; PHOTOELECTRON-SPECTRA; OSCILLATOR-STRENGTHS; ABSORPTION-SPECTRA; VACUUM ULTRAVIOLET AB In this article, available information on the cross sections and rate coefficients for collisional interactions of dichlorodifluoromethane (CCl2F2) with electrons is critically evaluated and synthesized. This gas has many industrial uses and is of atmospheric and environmental interest. The CCl2F2 molecule fragments rather extensively under electron impact, principally via dissociative ionization and dissociative attachment; the latter process is temperature dependent. Information is presented and discussed on: (1) electron scattering processes [cross sections for total electron scattering, momentum transfer, differential elastic electron scattering, integral elastic electron scattering, and inelastic electron scattering for rotational and vibrational (direct and indirect) excitation]; (2) electron impact ionization (cross sections for total, partial, and double ionization and coefficients for electron impact ionization); (3) electron attachment (electron attachment cross sections and rate constants and their energy and temperature dependencies, electron attachment coefficients, dissociative attachment fragment anions, and negative ion states); (4) optical emission under electron impact, and (5) electron transport coefficients (electron drift velocity and ratio of transverse electron diffusion coefficient to electron mobility). Based upon the assessment of published experimental data, recommended values of various cross sections and rate coefficients are generated in graphical and tabular form. Areas where additional data are needed are identified, such as the measurement of the cross sections for momentum transfer and electron impact dissociation of CCl2F2 into neutral species. (C) 1997 American Institute of Physics and American Chemical Society. C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. RP Christophorou, LG (reprint author), NIST,DIV ELECT,ELECT & ELECT ENGN LAB,GAITHERSBURG,MD 20899, USA. NR 113 TC 59 Z9 59 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD SEP-OCT PY 1997 VL 26 IS 5 BP 1205 EP 1237 PG 33 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA YA867 UT WOS:A1997YA86700003 ER PT J AU Vanderah, TA WongNg, W Huang, Q Roth, RS Geyer, RG Goldfarb, RB AF Vanderah, TA WongNg, W Huang, Q Roth, RS Geyer, RG Goldfarb, RB TI Crystal structures and properties of Ba4Fe2Ti10O27 and Ba3Fe10TiO20 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article DE barium iron titanium oxides; Ba4Fe2Ti10O27; Ba3Fe10TiO20; dielectric properties; magnetic properties; crystal structure; magnetic structure ID SOLIDS AB Crystal structures, dielectric properties, and magnetic behaviour of the newly prepared compounds Ba4Fe2Ti10O27 and Ba3Fe10Ti20 are described. Structural studies were carried out by single-crystal X-ray diffraction and neutron powder diffraction. Ba4Fe2Ti10O27 crystallizes with an eight-layer close-packed structure having a monoclinic unit cell [space group C2/m, No. 12; a = 19.828(1), b = 11.436(1), c = 9.9020(6) Angstrom, beta = 109.30(1)degrees; rho(calc) = 4.93 g/cm(3)] and is isostructural with Ba4Al2Ti10O27. Ba3Fe10TiO20 is structurally analogous to Ba3Al10TiO20 and exhibits an open-framework type structure with a monoclinic unit cell [I2/m, No. 12; a = 15.358(1), b = 11.818(1), c = 5.1771(3) Angstrom, beta = 91.231(4)degrees; rho(calc) = 4.73 g/cm(3)]. Neutron diffraction studies of Ba3Fe10TiO20 at room temperature revealed a magnetic lattice with reduced symmetry; an additional magnetic structure was observed at 13 K and below magnetic susceptibility measurements indicated that Ba4Fe2Ti10O27 is essentially paramagnetic; in contrast, Ba4Fe10TiO20 displays complex magnetic behaviour with transitions at 45 and 5 K. For Ba4Fe2TiO27 the values obtained for the permittivity and dielectric loss (tans) are 39 and 1 X 10(-3); for Ba3Fe10TiO20, 15 and 5 x 10(-4), respectively. The dielectric properties of both compounds exhibited minimal dependence on frequency in the measured regions (above 6 GHz). Published by Elsevier Science Ltd. C1 UNIV MARYLAND,DEPT MAT & NUCL ENGN,COLLEGE PK,MD 20742. NATL INST STAND & TECHNOL,ELECT & ELECT ENGN LAB,BOULDER,CO 80303. RP Vanderah, TA (reprint author), NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899, USA. RI Goldfarb, Ronald/A-5493-2011 OI Goldfarb, Ronald/0000-0002-1942-7974 NR 21 TC 10 Z9 10 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD SEP PY 1997 VL 58 IS 9 BP 1403 EP 1415 DI 10.1016/S0022-3697(97)00019-X PG 13 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA XY206 UT WOS:A1997XY20600016 ER PT J AU Colle, R Zimmerman, BE AF Colle, R Zimmerman, BE TI A compendium on the NIST radionuclidic assays of the massic activity of Ni-63 and Fe-55 solutions used for an international intercomparison of liquid scintillation spectrometry techniques SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE beta decay; efficiency tracing; hydrogen-3; intercomparison; iron-55; liquid scintillation (LS); measurements; nickel-63; radioactivity; spectrometry ID COUNTING EFFICIENCY; STANDARDIZATION; DECAY AB The National Institute of Standards and Technology recently participated in an international measurement intercomparison for Ni-63 and Fe-55, which was conducted amongst principal national radionuclidic metrology laboratories. The intercomparison was sponsored by EUROMET, and was primarily intended to evaluate the capabilities of liquid scintillation (LS) spectrometry techniques for standardizing nuclides that decay by low-energy beta-emission (like Ni-63) and by low-Z (atomic number) electron capture (like Fe-55). The intercomparison findings exhibit a very good agreement for Ni-63 amongst the various participating laboratories, including that for NIST, which suggests that the presently invoked LS methodologies are very capable of providing internationally-compatible standardizations for low-energy beta-emitters. The results for Fe-55 are in considerably poorer agreement, and demonstrated the existence of several unresolved problems. It has thus become apparent that there is a need for the various international laboratories to conduct rigorous, systematic evaluations of their LS capabilities in assaying radionuclides that decay by low-Z electron capture. RP Colle, R (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 53 TC 12 Z9 12 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 SEP-OCT PY 1997 VL 102 IS 5 BP 523 EP 549 DI 10.6028/jres.102.035 PG 27 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YK988 UT WOS:A1997YK98800001 PM 27805141 ER PT J AU Tsai, BK AF Tsai, BK TI Developments for a new spectral irradiance scale at the national institute of standards and technology SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE blackbody; filter radiometer; scale realization; spectral irradiance; uncertainty ID CRYOGENIC RADIOMETER AB Recent developments for a new spectral irradiance scale realization at the National Institute of Standards and Technology have been targeted to reduce the present relative expanded uncertainties of 0.67 % to 4.34 % (coverage factor of k = 2 and thus a 2 standard deviation estimate) in the spectral irradiance scale to 0.17 % for the range from 350 nm to 1100 nm. To accomplish this goal, a suite of filter radiometers calibrated using NIST's high accuracy cryogenic radiometer have been used to measure the temperature of a high-temperature blackbody. A comparison of the filter radiometer calibrations with the spectral irradiance scale along with an evaluation of the blackbody calibration technique have been performed. With the aid of a monochromator, the calibrated filter radiometers will then be utilized to calibrate primary and secondary spectral standard lamps at NIST. RP Tsai, BK (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 18 TC 5 Z9 5 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 SEP-OCT PY 1997 VL 102 IS 5 BP 551 EP 558 DI 10.6028/jres.102.036 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YK988 UT WOS:A1997YK98800002 PM 27805142 ER PT J AU Chu, PM Thorn, WJ Sams, RL Guenther, FR AF Chu, PM Thorn, WJ Sams, RL Guenther, FR TI On-demand generation of a formaldehyde-in-air standard SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE catalytic conversion of methanol; formaldehyde; formaldehyde standard; gas standards; vehicle emissions ID METHOXY AB The feasibility of using catalytic conversion of methanol to formaldehyde to produce standard amount of substance fractions of formaldehyde was examined. The conversion efficiencies of several catalysts were measured as a function of temperature, balance gas, catalyst bed length, and methanol amount of substance fraction in an effort to identify conditions which yield high and consistent conversion of methanol to formaldehyde. The highest observed conversion rate was (97 +/- 4)% using a molybdenum catalyst, where the error is the 2 sigma uncertainty. The conversion efficiency was found to be consistent over repeated cycles and over a long lifetime test, suggesting that a molybdenum catalyst is a viable candidate for a standard formaldehyde generator, particularly for low formaldehyde amount of substance fractions (< 15 mu mol/mol). RP Chu, PM (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 20 TC 5 Z9 5 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 SEP-OCT PY 1997 VL 102 IS 5 BP 559 EP 568 DI 10.6028/jres.102.037 PG 10 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YK988 UT WOS:A1997YK98800003 PM 27805143 ER PT J AU Wang, YC AF Wang, YC TI New method for measuring statistical distributions of partial discharge pulses SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE amplitude distributions; log normal distribution; partial discharges; random point process; time separation distributions ID STOCHASTIC PROPERTIES; CORONA; OXYGEN AB A new digital detection system is described for measuring pulsating partial discharges (PDs). The PD detection system can continuously record all PD pulses that occur over extended periods of time, with a minimum inter-pulse time separation of 6 mu s and a vertical amplitude resolution of 12 bits. Earlier PD detection systems detected PD pulse amplitude and time using complex custom-designed hardware while the present system continuously records the complete electrical waveform that carries the PD pulses using a commercial data acquisition board and extracts, in real time, the time and amplitude information of all PD pulses in software. The current approach considerably reduces the development and maintenance cost of the PD detection system, significantly increases the system portability and may prove to be a crucial step for transferring the digital PD detection and analysis technology developed in laboratories to industry. The features of the new system are illustrated by the study of dc-excited PD pulses occurring in a point-to-plane gap in air. A new surface-mediated burst mode of PDs is discovered in which a PD pulse has a certain probability to induce another pulse. The probability is determined for several gap voltages and is found to vary strongly with the applied voltage. RP NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 26 TC 10 Z9 11 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 SEP-OCT PY 1997 VL 102 IS 5 BP 569 EP 576 DI 10.6028/jres.102.038 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YK988 UT WOS:A1997YK98800004 PM 27805144 ER PT J AU Phillips, SD Eberhardt, KR Parry, B AF Phillips, SD Eberhardt, KR Parry, B TI Guidelines for expressing the uncertainty of measurement results containing uncorrected bias SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE bias; error; expanded uncertainty; measurement; uncertainty AB This paper proposes a method to extend the current ISO Guide to the Expression of Uncertainty in Measurement to include the case of known, but uncorrected, measurement bias. It is strongly recommended that measurement results be corrected for bias, however in some situations this may not be practical, hence an extension of the Guide is proposed to address this special situation. The method keeps with the spirit of the Guide in maintaining the link between uncertainty and statistical confidence. Similarly, the method maintains the transferability of one uncertainty statement to be included as a component in another uncertainty analysis. The procedure involves modifying the calculation of the expanded uncertainty, allowing it to become asymmetric about the measurement value. The method is compared to other alternative procedures, and an illustration of how it affects tolerance zones is presented. C1 BOEING CORP, SEATTLE, WA 98124 USA. RP Phillips, SD (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 3 TC 47 Z9 47 U1 1 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 SEP-OCT PY 1997 VL 102 IS 5 BP 577 EP 585 DI 10.6028/jres.102.039 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YK988 UT WOS:A1997YK98800005 PM 27805145 ER PT J AU Estler, WT AF Estler, WT TI A distribution-independent bound on the level of confidence in the result of a measurement SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE level of confidence; measurement; probability; uncertainty AB The Bienayme-Chebyshev Inequality provides a quantitative bound on the level of confidence of a measurement with known combined standard uncertainty and assumed coverage factor. The result is independent of the detailed nature of the probability distribution that characterizes knowledge of the measurand. RP Estler, WT (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 4 TC 6 Z9 7 U1 0 U2 1 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD SEP-OCT PY 1997 VL 102 IS 5 BP 587 EP 588 DI 10.6028/jres.102.040 PG 2 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YK988 UT WOS:A1997YK98800006 PM 27805146 ER PT J AU Hutchinson, JMR Unterweger, M AF Hutchinson, JMR Unterweger, M TI Radionuclide metrology and its applications - ICRM '97 Gaithersburg, MD May 18-23, 1997 SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Editorial Material RP Hutchinson, JMR (reprint author), NATL INST STAND & TECHNOL, PHYS LAB, IONIZING RADIAT DIV, GAITHERSBURG, MD 20899 USA. NR 0 TC 0 Z9 0 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 SEP-OCT PY 1997 VL 102 IS 5 BP 589 EP 593 DI 10.6028/jres.102.041 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA YK988 UT WOS:A1997YK98800007 PM 27805147 ER PT J AU Pesce, JJ McKenna, GB AF Pesce, JJ McKenna, GB TI Prediction of the subyield extension and compression responses of glassy polycarbonate from torsional measurements SO JOURNAL OF RHEOLOGY LA English DT Article ID STRAIN; REJUVENATION; RUBBER; BEHAVIOR AB Modeling of the response of solidlike polymers is often difficult, not only due to the highly nonlinear behavior of the materials but also because of the difficulty of obtaining relevant material data in the laboratory. Here, we examine the possibility of using concepts from finite elasticity theory to describe the isochronal single-step stress relaxation response for a polymer glass (polycarbonate) far below its glass transition. Torque and normal force measurements from torsional stress relaxation experiments are used to obtain isochoric values for the derivatives W-1 and W-2 of the strain energy density function in terms of the deformation invariants at specific time values (isochrones). The values of W-1 and W-2 are then used to determine isochronal values of the Valanis-Landel [Valanis, K. C. and R. F. Landel ''The St-ain-Energy Function of a Hyperelastic Material in Terms of the Extension Ratios,'' J. Appl. Phys. 38, 2997-3002 (1967).] (VL) function derivatives omega'(lambda) and to predict the tension and compression responses for different deformations lambda below yield. It is found that, for the conditions examined, the experimentally obtained tension and compression responses are well described within the VL framework, despite the fact that polycarbonate is a compressible material. This success suggests that the set of experiments required to describe the nonlinear behavior of glassy materials may be smaller than previously thought. Also, volumetric measurements in the uniaxial deformations indicate a densification of the glass at large deformations and long relaxation times, which is consistent with concepts in the literature that invoke mechanically accelerated aging to describe mechanical and structural interactions in the physical aging of glassy polymers. C1 NATL INST STAND & TECHNOL,US DEPT COMMERCE,STRUCT & MECH GRP,DIV POLYMERS,GAITHERSBURG,MD 20899. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 37 TC 10 Z9 10 U1 2 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0148-6055 J9 J RHEOL JI J. Rheol. PD SEP-OCT PY 1997 VL 41 IS 5 BP 929 EP 942 DI 10.1122/1.550843 PG 14 WC Mechanics SC Mechanics GA XU916 UT WOS:A1997XU91600001 ER PT J AU Hackley, VA AF Hackley, VA TI Colloidal processing of silicon nitride with poly(acrylic acid) .1. Adsorption and electrostatic interactions SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 97th Annual Meeting of the American-Ceramic-Society CY MAY 01-03, 1995 CL CINCINNATI, OH SP Amer Ceram Soc ID WEAK POLYELECTROLYTES; SURFACES; POWDER AB The role of poly(acrylic acid) (PAA) in the dispersion of silicon nitride suspensions was investigated experimentally, The effects of concentration, relative molecular mass, and suspension pH were evaluated, The ionization of PAA was characterized by potentiometric titration and indicated a pH-dependent conformational transition, The isoelectric point for silicon nitride decreased from pH 6.3 to pH 3 as the PAA concentration increased, roughly independent of relative molecular mass. A broadening of the stability region for silicon nitride was attributed to this effect. Redispersion in alkaline media, subsequent to destabilization by surface-charge neutralization, improved following preadsorption of PAA in acidic media. This effect was attributed to formation of a protective polymer adlayer on the surface, which prevented primary minimum aggregation; an electrosteric contribution also may be present. The influence of free polymer on the suspension properties also is discussed. RP NIST, MAT SCI & ENGN LAB, DIV CERAM, GAITHERSBURG, MD 20899 USA. NR 34 TC 176 Z9 186 U1 0 U2 7 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 SEP PY 1997 VL 80 IS 9 BP 2315 EP 2325 PG 11 WC Materials Science, Ceramics SC Materials Science GA XX488 UT WOS:A1997XX48800016 ER PT J AU Lee, SK Wuttiphan, S Lawn, BR AF Lee, SK Wuttiphan, S Lawn, BR TI Role of microstructure in hertzian contact damage in silicon nitride .1. Mechanical characterization SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID FRACTURE-RESISTANCE MECHANISM; HETEROGENEOUS GRAIN-STRUCTURE; TOUGHNESS CURVES; BRITTLE SOLIDS; POLYCRYSTALLINE CERAMICS; STRENGTH DEGRADATION; 2-PHASE CERAMICS; CYCLIC FATIGUE; INDENTATION; STRESS AB In this Part I of a two-part study of Hertzian indentation in silicon nitride we characterize irreversible contact damage as a function of microstructure. Three controlled silicon nitride microstructures are examined, representing a progression toward greater long-crack toughness: fine (F), bimodal with predominantly equiaxed alpha grains; medium (M), bimodal with mostly beta grains of intermediate size; and coarse (C), with almost exclusively elongated beta grains, An effect of increasing the microstructural heterogeneity in this sequence is to suppress ring cracking around the indenter, ultimately to a degree beyond that expected from increased toughness alone, Along with the crack suppression is a parallel tendency to enhanced damage accumulation beneath the indenter, such that the contact in the coarsest microstructure is predominantly quasi-plastic, The characterization of damage includes the following: determination of indentation stress-strain curves, to measure the level of quasi-plasticity; measurement of threshold loads for the initiation of ring cracking and subsurface yield, to quantify the competing damage processes; and measurement of characteristic dimensions of the ensuing cracks and deformation zones in their well-developed stages. These quantitative results are considered in terms of formal contact mechanics, along with finite element modeling to generate the essentially elastic-plastic fields in the different silicon nitride structures, This contact mechanics description serves also as the basis for subsequent analysis of strength degradation in Part II, Implications concerning microstructural design of silicon nitride ceramics for specific applications, notably bearings, are considered. RP NIST, MAT SCI & ENGN LAB, GAITHERSBURG, MD 20899 USA. NR 73 TC 86 Z9 86 U1 1 U2 7 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 SEP PY 1997 VL 80 IS 9 BP 2367 EP 2381 PG 15 WC Materials Science, Ceramics SC Materials Science GA XX488 UT WOS:A1997XX48800023 ER PT J AU Percival, DB Mofjeld, HO AF Percival, DB Mofjeld, HO TI Analysis of subtidal coastal sea level fluctuations using wavelets SO JOURNAL OF THE AMERICAN STATISTICAL ASSOCIATION LA English DT Article DE coastal sea level variability; discrete wavelet transform; natural hazards; time series analysis; tsunamis ID NORTH-AMERICA; WEST-COAST; REPRESENTATION; TRANSFORM; CURRENTS; SHELF; OCEAN AB Subtidal coastal sea level fluctuations affect coastal ecosystems and the consequences of destructive events such as tsunamis. We analyze a time series of subtidal fluctuations at Crescent City, California, during 1980-1991 using the maximal overlap discrete wavelet transform (MODWT). Our analysis shows that the variability in these fluctuations depends on the season for scales of 32 days and less. We show how the MODWT characterizes nonstationary behavior succinctly and how this characterization can be used to improve forecasts of inundation during tsunamis and storm surges. Pie provide pseudocode and enough details so that data analysts in other disciplines can readily apply MODWT analysis to other nonstationary time series. C1 UNIV WASHINGTON, DEPT STAT, SEATTLE, WA 98195 USA. MATH SOFT INC, SEATTLE, WA 98109 USA. NOAA, PACIFIC MARINE ENVIRONM LAB, SEATTLE, WA 98115 USA. UNIV WASHINGTON, SCH OCEANOG, SEATTLE, WA 98195 USA. RP UNIV WASHINGTON, APPL PHYS LAB, SEATTLE, WA 98195 USA. NR 40 TC 94 Z9 97 U1 0 U2 8 PU AMER STATISTICAL ASSOC PI ALEXANDRIA PA 732 N WASHINGTON ST, ALEXANDRIA, VA 22314-1943 USA SN 0162-1459 EI 1537-274X J9 J AM STAT ASSOC JI J. Am. Stat. Assoc. PD SEP PY 1997 VL 92 IS 439 BP 868 EP 880 DI 10.2307/2965551 PG 13 WC Statistics & Probability SC Mathematics GA XU878 UT WOS:A1997XU87800007 ER PT J AU Ralph, FM AF Ralph, FM TI Use of ducting theory in an observed case of gravity waves SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article RP Ralph, FM (reprint author), NOAA,ERL,ENVIRONM TECHNOL LAB,MAIL CODE REET7,325 BROADWAY,BOULDER,CO 80303, USA. NR 8 TC 6 Z9 6 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 SEP 1 PY 1997 VL 54 IS 17 BP 2237 EP 2239 DI 10.1175/1520-0469(1997)054<2237:COUODT>2.0.CO;2 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XT769 UT WOS:A1997XT76900006 ER PT J AU Griesmann, U Musielok, J Wiese, WL AF Griesmann, U Musielok, J Wiese, WL TI Branching fractions and transition probabilities for transitions from 2p(4) 3p, 2p(4) 3d, and 2p(4) 4s levels of Ne II SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID RADIATIVE LIFETIMES; ARGON AB Branching fractions for electric dipole transitions from 2p(4)3p, 2p(4)3d, and 2p(4)4s upper levels in singly ionized neon atoms excited in a high-current hollow-cathode lamp were measured. Transition probabilities for many weak intercombination lines were determined for the first time to the authors' knowledge. The measurements were carried out with two different techniques to minimize the effect of systematic errors, first in an experiment with a 2-m grating monochromator and then with a Fourier transform spectrometer. The uncertainty of the branching fraction data is 4%(1 sigma) for lines corresponding to LS-allowed transitions and 30%(1 sigma) for weak intercombination lines. For 14 upper levels complete sets of transitions could be measured that enabled us to determine absolute transition probabilities when lifetime data for the upper levels were available. (C) 1997 Optical Society of America. RP Griesmann, U (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 25 TC 20 Z9 20 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 SEP PY 1997 VL 14 IS 9 BP 2204 EP 2211 DI 10.1364/JOSAB.14.002204 PG 8 WC Optics SC Optics GA XU650 UT WOS:A1997XU65000003 ER PT J AU Chi, PH Simons, DS Wickenden, AE Koleske, DD AF Chi, PH Simons, DS Wickenden, AE Koleske, DD TI Repeatability of Si concentration measurements in Si-doped GaN films SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A LA English DT Article ID ION; EPITAXY; ENERGY AB In high mass resolution secondary ion mass spectrometry Cs+ depth profile measurements of Si in GaN films, the secondary ion intensity ratio of Si-28(-) to the matrix Ga-69(-) signal has been observed to be poorly repeatable from measurement to measurement. In some cases the Ga-69(-) signals from adjacent areas showed different intensity levels even though the Si-28(-) intensities were similar. Variation of the Ga-69(-) matrix signal from run to run creates a large uncertainty in the determination of the Si concentration in a GaN film when a relative. sensitivity factor is used. The changes in Ga-69(-) intensity from repeat measurements have been determined to be affected by the instrument vacuum condition, ion energy distribution, sample charging, and type of sample holder used in the measurement. (C) 1997 American Vacuum Society. C1 USN, RES LAB, WASHINGTON, DC 20375 USA. RP NATL INST STAND & TECHNOL, CHEM SCI & TECHNOL LAB, GAITHERSBURG, MD 20899 USA. NR 15 TC 4 Z9 4 U1 0 U2 0 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 EI 1520-8559 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A PD SEP-OCT PY 1997 VL 15 IS 5 BP 2565 EP 2568 DI 10.1116/1.580772 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XY204 UT WOS:A1997XY20400019 ER PT J AU Knowles, MP Leone, SR AF Knowles, MP Leone, SR TI Generation of a velocity selected, pulsed source of hyperthermal (1-10 eV) neutral metal atoms for thin film growth studies SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID TIME-OF-FLIGHT; CHEMICAL VAPOR-DEPOSITION; EXCIMER-LASER ABLATION; MOLECULAR-DYNAMICS; SI; COPPER; BEAMS; SIMULATIONS; TUNGSTEN; DISTRIBUTIONS AB The laser-induced vaporization by back-illumination technique is shown to generate well characterized, repetitively pulsed beams of hyperthermal neutral Co atoms with kinetic energies ranging from 1 to 10 eV. At a repetition rate of 10 Hz, and a distance of 0.53 m, 2 X 10(11) Co atoms/ cm(2) per pulse are produced with less than 2 X 10(7) ions/cm(2) per pulse, These beams can be used as an ultrahigh vacuum deposition source for thin film growth studies. The hyperthermal beam is deposited on polished Si(100) wafers and particulates deposited by the beam are detected using ex situ scanning electron microscopy. A mechanical chopper allows tunable velocity selection of the fast neutral atoms and is shown to eliminate particulates from the beam. Line-of-sight time-of-fight quadrupole mass spectrometry is used to measure kinetic energy distributions. Applications of the novel hyperthermal neutral atom source to kinetic energy enhanced neutral epitaxy are discussed. (C) 1997 American Vacuum Society. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Knowles, MP (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 47 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 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD SEP-OCT PY 1997 VL 15 IS 5 BP 2709 EP 2716 DI 10.1116/1.580945 PG 8 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XY204 UT WOS:A1997XY20400041 ER PT J AU Bard, A Berggren, KK Wilbur, JL Gillaspy, JD Rolston, SL McClelland, JJ Phillips, WD Prentiss, M Whitesides, GM AF Bard, A Berggren, KK Wilbur, JL Gillaspy, JD Rolston, SL McClelland, JJ Phillips, WD Prentiss, M Whitesides, GM TI Self-assembled monolayers exposed by metastable argon and metastable helium for neutral atom lithography and atomic beam imaging SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID ELECTRON; YIELDS AB We used a beam of noble gas atoms in a metastable excited state to expose a thin (1.5 nm) self-assembled monolayer resist applied over a gold-coated silicon wafer. We determined exposure damage as a function of dose of metastable atoms by processing the samples in a wet-chemical etch to remove the gold from unprotected regions and then measuring the reflectivity with a laser and observing the microstructure with an atomic force microscope. We found that the minimum dose required to damage the resist substantially was 1.7(3)x10(15) atoms/cm(2) for metastable helium, and 25(7)X10(15) atoms/cm(2) for metastable argon. (C) 1997 American Vacuum Society. C1 HARVARD UNIV,DEPT PHYS,CAMBRIDGE,MA 02138. HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138. NATL INST STAND & TECHNOL,DIV ELECTRON & OPT PHYS,GAITHERSBURG,MD 20899. RP Bard, A (reprint author), NATL INST STAND & TECHNOL,ATOM PHYS DIV,GAITHERSBURG,MD 20899, USA. RI rolston, steven/L-5175-2013; McClelland, Jabez/A-2358-2015 OI rolston, steven/0000-0003-1671-4190; McClelland, Jabez/0000-0001-5672-5965 NR 18 TC 52 Z9 53 U1 1 U2 4 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 SEP-OCT PY 1997 VL 15 IS 5 BP 1805 EP 1810 DI 10.1116/1.589529 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA YC387 UT WOS:A1997YC38700040 ER PT J AU Ghosh, P Patterson, GW Wikfors, GH AF Ghosh, P Patterson, GW Wikfors, GH TI Use of an improved internal-standard method in the quantitative sterol analyses of phytoplankton and oysters SO LIPIDS LA English DT Article ID CRASSOSTREA-VIRGINICA; TETRASELMIS; CHOLESTEROL AB Most work reporting the sterol composition of living organisms has not been done quantitatively, although good quantitative data are available for fatty acids and many other cellular components using an internal-standard method that compensates for errors during gas chromatographic analysis. In this paper, we report on the use of 7-stigmastenyl acetate as an internal standard for sterol analysis in two species of phytoplankton and oysters produced with two different diets. This internal-standard method provides an internal standard for this entire process of analysis, not just the gas chromatographic analysis. When analyzing 50-mu g samples of cholesterol acetate after hydrolysis and acetylation, about 30% of the sample was lost, resulting in a 30% error using the older external-standard method. Using the internal-standard method, the analysis error was less than 2%. Losses of sterol during analysis apparently are greater with plant and animal samples than with pure sterol standards. This internal-standard method was shown to be extremely useful, especially for samples with less than 500 mu g of sterol. Finally, the standard error in sterol analysis is much lower when the internal-standard method is used, allowing statistical distinctions that are not possible otherwise. Use of 7-stigmastenyl acetate as an internal standard offers several advantages over the use of cholestane. C1 UNIV MARYLAND,DEPT PLANT BIOL,COLLEGE PK,MD 20742. NATL MARINE FISHERIES SERV,NE FISHERIES SCI CTR,MILFORD,CT 06460. NR 15 TC 3 Z9 3 U1 0 U2 0 PU AMER OIL CHEMISTS SOC PI CHAMPAIGN PA 1608 BROADMOOR DRIVE, CHAMPAIGN, IL 61821-0489 SN 0024-4201 J9 LIPIDS JI Lipids PD SEP PY 1997 VL 32 IS 9 BP 1011 EP 1014 DI 10.1007/s11745-997-0131-z PG 4 WC Biochemistry & Molecular Biology; Nutrition & Dietetics SC Biochemistry & Molecular Biology; Nutrition & Dietetics GA XW380 UT WOS:A1997XW38000014 PM 9307944 ER PT J AU LeckeMitchell, KM Mullin, K AF LeckeMitchell, KM Mullin, K TI Floating marine debris in the US Gulf of Mexico SO MARINE POLLUTION BULLETIN LA English DT Article RP SE FISHERIES SCI CTR, NATL MARINE FISHERIES SERV, PO DRAWER 1207, PASCAGOULA, MS 39568 USA. NR 8 TC 12 Z9 12 U1 1 U2 12 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 SEP PY 1997 VL 34 IS 9 BP 702 EP 705 DI 10.1016/S0025-326X(97)00027-1 PG 4 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA YF823 UT WOS:A1997YF82300015 ER PT J AU Beck, KM Fair, P McFee, W Wolf, D AF Beck, KM Fair, P McFee, W Wolf, D TI Heavy metals in livers of bottlenose dolphins stranded along the South Carolina coast SO MARINE POLLUTION BULLETIN LA English DT Article ID TRACE-METALS; MARINE MAMMALS; SELENIUM; TISSUE C1 NATL MARINE FISHERIES SERV, CHARLESTON LAB, CHARLESTON, SC 29422 USA. NR 21 TC 47 Z9 50 U1 0 U2 4 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 SEP PY 1997 VL 34 IS 9 BP 734 EP 739 DI 10.1016/S0025-326X(97)00071-4 PG 6 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA YF823 UT WOS:A1997YF82300020 ER PT J AU Kalvaitis, AN AF Kalvaitis, AN TI A critical capability - Submersible sampling and sensing SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Editorial Material RP Kalvaitis, AN (reprint author), NATL OCEAN & ATMOSPHER ADM,NATL UNDERSEA RES PROGRAM,SILVER SPRING,MD 20910, USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU MARINE TECHNOLOGY SOC INC PI WASHINGTON PA C/O I CLAYION MATTHEWS, 1828 L ST, NW, 9TH FL, WASHINGTON, DC 20036 SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD FAL PY 1997 VL 31 IS 3 BP 68 EP 71 PG 4 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA YG817 UT WOS:A1997YG81700009 ER PT J AU Kiladis, GN Weickmann, KM AF Kiladis, GN Weickmann, KM TI Horizontal structure and seasonality of large-scale circulations associated with submonthly tropical convection SO MONTHLY WEATHER REVIEW LA English DT Article ID ROSSBY-WAVE PROPAGATION; AUSTRALIAN MONSOON; VERTICAL STRUCTURE; NORTHERN WINTER; PACIFIC-OCEAN; DISTURBANCES; FLOW; FLUCTUATIONS; HEMISPHERE; ATMOSPHERE AB The relationship between deep tropical convection and large-scale atmospheric circulation in the 6-30-day period range is examined. Regression relationships between filtered outgoing longwave radiation at various locations in the Tropics and 200- and 850-mb circulation are mapped for the standard seasons, and the spatial structure and seasonal dependence of the results are interpreted in view of the basic-state circulation. In regions where the convection is embedded in upper-level easterlies, anomalous equatorial easterly flow is typically present at 200 mb within and to the west of the convective signal, along with patterns of meridional outflow into subtropical anticyclonic perturbations. Lagged relationships suggest that the convection is forcing the circulation in many of these cases. The outflow and subtropical circulations are strongest into the winter hemisphere during the solstitial seasons, with more symmetric signals about the equator seen in the equinoctial seasons. The longitudinal positioning of the subtropical features with respect to the convection varies but is generally located due poleward or just to the east of the convection. There tends to be a first baroclinic mode vertical structure to these circulations, such that equatorial westerlies are present at 850 mb within the convection, with closed circulations on either side of the equator resembling equatorial Rossby modes especially common over the Atlantic and Pacific sectors. As a contrast, in regions located within upper-level westerlies or along the margin of influence of upper westerly disturbances, convection appears to be forced by upper-level wave energy propagating into the deep Tropics, with the heating located in the upward motion region ahead of upper-level troughs. This occurs over the Atlantic and eastern Pacific sectors during northern winter and spring, and over Australia, the South Pacific, and South America during southern summer, when upper westerlies are at relatively low latitudes where they can interact with deep tropical convection. The results confirm theoretical and modeling ideas that suggest that Rossby wave energy is able to propagate into the deep Tropics in regions where upper-level westerlies exist in the Tropics. C1 NOAA,CLIMATE DIAGNOST CTR,BOULDER,CO 80303. RP Kiladis, GN (reprint author), NOAA,AERON LAB,R E AL3,325 BROADWAY,BOULDER,CO 80303, USA. NR 41 TC 79 Z9 80 U1 0 U2 4 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 SEP PY 1997 VL 125 IS 9 BP 1997 EP 2013 DI 10.1175/1520-0493(1997)125<1997:HSASOL>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU111 UT WOS:A1997XU11100001 ER PT J AU Black, PG Proni, JR Wilkerson, JC Samsury, CE AF Black, PG Proni, JR Wilkerson, JC Samsury, CE TI Oceanic rainfall detection and classification in tropical and subtropical mesoscale convective systems using underwater acoustic methods SO MONTHLY WEATHER REVIEW LA English DT Article ID RAINDROP SPECTRA; AMBIENT NOISE; SOUND; PRECIPITATION; WIND; BUBBLES; STORMS; IMPACT AB Measurements of the underwater sound produced by rain were made at three U.S. coastal sites in a study to determine the feasibility and limitations of the acoustic detection and classification of rainfall over water. In the analysis of the rain sound spectra, concurrent radar reflectivity observations were used to identify convective and stratiform regions of the precipitating clouds overhead. It was found that acoustic classifications of rainfall as to type, based on information in the 4-30-kHz frequency band, were in general agreement with radar-derived classifications. The classification technique is based on use of an acoustic discriminant, D-R, defined as the difference in average spectral levels between the 10-30- and 4-10-kHz bands. A high correlation was found between sound spectrum levels (in decibels) in the 4-10-kHz frequency band and radar reflectivity, dBZ, suggesting the possible use of the 4-10-kHz band sound spectral level as a classification tool using spatially distributed hydrophones in the same way that radar reflectivity is used in classifying precipitation. The results demonstrate the feasibility of the acoustic method for detecting and classifying rainfall at sea. C1 NOAA,ATLANTIC OCEANOG & METEOROL LAB,OCEAN ACOUST DIV,MIAMI,FL 33149. NOAA,ATLANTIC OCEANOG & METEOROL LAB,HURRICANE RES DIV,MIAMI,FL 33149. NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,OFF RES & APPLICAT,WASHINGTON,DC 20233. NR 64 TC 16 Z9 16 U1 4 U2 4 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 SEP PY 1997 VL 125 IS 9 BP 2014 EP 2042 DI 10.1175/1520-0493(1997)125<2014:ORDACI>2.0.CO;2 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU111 UT WOS:A1997XU11100002 ER PT J AU Nakamura, H Nakamura, M Anderson, JL AF Nakamura, H Nakamura, M Anderson, JL TI The role of high- and low-frequency dynamics in blocking formation SO MONTHLY WEATHER REVIEW LA English DT Article ID GENERAL-CIRCULATION MODEL; TIME-MEAN FLOW; LIFE-CYCLES; ATMOSPHERIC BLOCKING; PERSISTENT ANOMALIES; TRANSIENT EDDIES; NORTH-PACIFIC; ROSSBY-WAVE; EXPLOSIVE CYCLOGENESIS; SCALE CYCLOGENESIS AB Time evolutions of prominent blocking flow configurations over the North Pacific and Europe are compared based upon composites for the 30 strongest events observed during 27 recent winter seasons. Fluctuations associated with synoptic-scale migratory eddies have been filtered out before the compositing. A quasi-stationary wave train across the Atlantic is evident during the blocking amplification over Europe, while no counterpart is found to the west of the amplifying blocking over the North Pacific. Correlation between the tropopause-level potential vorticity (PV) and meridional wind velocity associated with the amplifying blocking is found to be negative over Europe in association with the anticyclonic evolution of the low-PV center, but it is almost zero over the North Pacific. Feedback from the synoptic-scale eddies, as evaluated in the form of 250-mb geopotential height tendency due to the eddy vorticity flux convergence, accounts for more than 75% of the observed amplification for the Pacific blocking and less than 45% for the European blocking. This difference is highlighted in two types of ''contour advection with surgery'' experiments. In one of them PV contours observed four days before the peak blocking time were advected by composite time series of the low-pass-filtered observational wind, and in the other experiment they were advected by the low-pass-filtered wind from which the transient eddy feedback evaluated as above had been removed at every time step. Hence, the latter data should be dominated by low-frequency dynamics. For the European blocking both experiments can reproduce the anticyclonic evolution of low-PV air within a blocking ridge as observed. For the Pacific blocking, in contrast, the observed intrusion of low-PV air into the higher latitudes cannot be reproduced without the transient feedback. Furthermore, in a barotropic model initialized with the composite 250-mb flow observed three days before the peak time, a simulated blocking development over the North Pacific is more sensitive to the insertion of the observed transient feedback than that over Europe. These results suggest that the incoming wave activity flux associated with a quasi-stationary Rossby wave train is of primary importance in the blocking formation over Europe, whereas the forcing by the synoptic-scale transients is indispensable to that over the North Pacific. C1 MIT, CTR METEOROL & PHYS OCEANOG, CAMBRIDGE, MA 02139 USA. PRINCETON UNIV, NOAA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08544 USA. RP UNIV TOKYO, FAC SCI, DEPT EARTH & PLANETARY PHYS, BUNKYO KU, 2-11-16 YAYOI, TOKYO 113, JAPAN. NR 53 TC 150 Z9 158 U1 0 U2 16 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD SEP PY 1997 VL 125 IS 9 BP 2074 EP 2093 DI 10.1175/1520-0493(1997)125<2074:TROHAL>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU111 UT WOS:A1997XU11100005 ER PT J AU Bringi, VN Knupp, K Detwiler, A Liu, L Caylor, IJ Black, RA AF Bringi, VN Knupp, K Detwiler, A Liu, L Caylor, IJ Black, RA TI Evolution of a Florida thunderstorm during the convection and precipitation/electrification experiment: The case of 9 August 1991 SO MONTHLY WEATHER REVIEW LA English DT Article ID PRECIPITATION DEVELOPMENT; MULTIPARAMETER RADAR; ATTENUATION-CORRECTION; MEXICO THUNDERSTORMS; POLARIZATION RADAR; DIFFERENTIAL PHASE; ELECTRIC-FIELD; ELECTRIFICATION; CLOUDS; RAIN AB The relationships among kinematic, microphysical, and electric field properties within a multicell Florida thunderstorm are investigated using observations from three Doppler radars (one with multiple wavelength and polarization diversity capabilities), four instrumented penetrating aircraft, a surface-based electric field mill network, and other observation facilities. The storm was convectively active for about 1 h and at least five primary cells developed within the storm during this time, one of which went through three consecutive development cycles. The updrafts in this storm were 2-4 km wide, exhibited bubble-like evolution, and had lifetimes of 10-20 min. The maximum updraft determined by the multiple Doppler analysis was about 20 m s(-1). A differential reflectivity (Z(DR)) ''column,'' indicating regions containing millimeter-size raindrops, extending above the freezing level, was associated with each cell during its developing stages. This column reached altitudes exceeding 6 km (-8 degrees C) in the stronger updrafts. As the Z(DR) columns reached maximum altitude, a ''cap'' of enhanced linear depolarization ratio (LDR) and enhanced 3-cm wavelength attenuation (A(3)) formed, overlapping the upper regions of the Z(DR) column. These parameters indicate rapid development of mixed-phase conditions initiated by freezing of supercooled raindrops. Lightning was observed only in the central and strongest convective cell. Electric fields exceeding 10 kV m(-1) were noted during aircraft penetrations in this as well as several other cells that did not produce lightning. Fields exceeding 1 kV m(-1) were noted by the instrumented aircraft at midcloud levels within a few minutes of development of mixed-phase conditions at these levels or aloft. The first intracloud lightning was detected by the surface field mill network within 5 min of development of mixed-phase conditions aloft in the first cycle of development in the central cell, and the first cloud-to-ground event was noted within 9 min of this development. Lightning continued through two additional cycles of updraft growth in this central region and diminished as the convection subsided after about 30 min. Aircraft-measured electric fields and lightning retrievals from the surface field meter network are consistent with a tendency for negative charge to accumulate above the 6.5 km (-12 degrees C) level within regions of radar reflectivity maxima and for positive charge to accumulate in the anvil region well above 9 km (-30 degrees C). C1 UNIV ALABAMA,HUNTSVILLE,AL 35899. S DAKOTA SCH MINES & TECHNOL,RAPID CITY,SD. S CHINA UNIV TECHNOL,GUANGZHOU,PEOPLES R CHINA. SCI SYST & APPLICAT INC,LANHAM,MD. NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33149. RP Bringi, VN (reprint author), COLORADO STATE UNIV,DEPT ELECT ENGN,FT COLLINS,CO 80523, USA. RI Black, Robert/C-9617-2009 OI Black, Robert/0000-0001-6938-125X NR 60 TC 59 Z9 61 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 SEP PY 1997 VL 125 IS 9 BP 2131 EP 2160 DI 10.1175/1520-0493(1997)125<2131:EOAFTD>2.0.CO;2 PG 30 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU111 UT WOS:A1997XU11100008 ER PT J AU Arritt, RW Rink, TD Segal, M Todey, DP Clark, CA Mitchell, MJ Labas, KM AF Arritt, RW Rink, TD Segal, M Todey, DP Clark, CA Mitchell, MJ Labas, KM TI The great plains low-level jet during the warm season of 1993 SO MONTHLY WEATHER REVIEW LA English DT Article ID CENTRAL UNITED-STATES; SUMMER FLOODS; PRECIPITATION; QUALITY; STREAKS AB Hourly wind profiler observations from the NOAA Profiler Network were used to develop a climatology of the low-level jet (LLJ) over the Great Plains of the central United States from April to September of 1993. The peak precipitation episode of the 1993 flood was associated with a sustained period of high incidence of strong low-level jets (over 20 m s(-1)). Consistent with previous studies, strong low-level jets were found to be promoted in the warm sector of an extratropical cyclone. Comparison of datasets formulated using velocity variance thresholds with unthresholded data similar to the operational hourly data suggests that the profiler observations often were contaminated by radar returns from migrating birds, especially during the months of April and May. The strong low-level jets during the peak precipitation episode of the 1993 hood over the upper Mississippi River basin were associated with a high-amplitude upper-level wave pattern over and upstream of the continental United States. Separating the composite 850-mb wind for strong low-level jets into geostrophic and ageostrophic components showed that the magnitudes of the ageostrophic component and the anomalous geostrophic component were comparable. C1 NATL WEATHER SERV,PLEASANT HILL,MO. NATL WEATHER SERV,CHICAGO,IL. RP Arritt, RW (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT AGRON,3010 AGRON HALL,AMES,IA 50011, USA. NR 27 TC 70 Z9 72 U1 1 U2 12 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 SEP PY 1997 VL 125 IS 9 BP 2176 EP 2192 DI 10.1175/1520-0493(1997)125<2176:TGPLLJ>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU111 UT WOS:A1997XU11100010 ER PT J AU Zupanski, D AF Zupanski, D TI A general weak constraint applicable to operational 4DVAR data assimilation systems SO MONTHLY WEATHER REVIEW LA English DT Article ID VARIATIONAL DATA ASSIMILATION; METEOROLOGICAL DATA ASSIMILATION; ATMOSPHERIC DATA ASSIMILATION; CONVECTIVE ADJUSTMENT SCHEME; STEP-MOUNTAIN COORDINATE; QUASI-GEOSTROPHIC MODEL; KALMAN FILTER; ERROR STATISTICS; PREDICTION; COVARIANCES AB A technique to apply the forecast model as a general weak constraint in a complex variational algorithm, such as NCEP's regional 4DVAR data assimilation system, is presented. The proposed definition of the model error has a flexible time resolution for the random error term. It has a potential for operational application, because the coarse time resolution of the random error term and a diagonal in time random error covariance matrix, as used in this study, require less computational space. The results presented in this study strongly indicate the need for a weak constraint (as opposed to a strong constraint formulation) in order to get the full benefit of a 4DVAR method. The inclusion of the model error term, even only the systematic error part, gives a main contribution to the capability of the 4DVAR method to outperform the optimal interpolation method. C1 NCEP,UCAR VISITING RES PROGRAM,WASHINGTON,DC. NR 54 TC 114 Z9 117 U1 0 U2 2 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 SEP PY 1997 VL 125 IS 9 BP 2274 EP 2292 DI 10.1175/1520-0493(1997)125<2274:AGWCAT>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU111 UT WOS:A1997XU11100017 ER PT J AU DeJong, A Hsing, K Su, D AF DeJong, A Hsing, K Su, D TI A VoD application implemented in Java SO MULTIMEDIA TOOLS AND APPLICATIONS LA English DT Article; Proceedings Paper CT 13th Meeting of the Digital-Audio-Visual-Council (DAVIC) CY JUN 17-21, 1996 CL NEW YORK, NY SP Digital Audio Visual Council, Columbia Univ DE Video on Demand; Java; DSM-CC; DAVIC; Set-Top Unit AB This article describes an implementation of a Video-on-Demand (VoD) system for the VoD interoperability test laboratory of the National Institute of Standards and Technology. It describes how Java can be used to implement the client side of a DAVIC based client-server system, which consists of a video server and a Set-Top Unit (STU) client. The communication between the video server and the STU is based on the Digital Storage Media Command and Control (DSM-CC) protocols. The VoD application is defined as a set of Java classes. These classes implement the graphical interfaces for user navigation and control. While this system is compliant with DAVIC specifications, it also permits an elegant integration of DAVIC services to the Internet environment. RP DeJong, A (reprint author), NATL INST STAND & TECHNOL,INFORMAT TECHNOL LAB,MULTIMEDIA & DIGITAL VIDEO GRP,GAITHERSBURG,MD 20899, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1380-7501 J9 MULTIMED TOOLS APPL JI Multimed. Tools Appl. PD SEP PY 1997 VL 5 IS 2 BP 161 EP 170 PG 10 WC Computer Science, Information Systems; Computer Science, Software Engineering; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA XV892 UT WOS:A1997XV89200005 ER PT J AU Dagata, JA AF Dagata, JA TI Evaluation of scanning Maxwell-stress microscopy for SPM-based nanoelectronics SO NANOTECHNOLOGY LA English DT Article; Proceedings Paper CT Tsukuba Workshop on Scanning Probe-Based Nanoelectronics (SP-NANO 96) CY DEC 19-20, 1996 CL TSUKUBA, JAPAN SP Agcy Ind Sci & Technol, Fdn Adv Technol Inst ID FORCE MICROSCOPY; FABRICATION; OXIDATION AB A preliminary evaluation of the compatibility, spatial resolution, and sensitivity of scanning Maxwell-stress microscopy (SMM) as an in situ diagnostic technique for SPM oxidation of silicon is presented. These results indicate that SMM will provide us with a more detailed understanding of the reaction mechanism which occurs at the tip-sample junction during SPM oxidation. SMM also appears to be a promising technique for simultaneously investigating dimensional and electrical properties of molecular distributions within highly complex micro-environments such as phase-separated polymer systems. This effort to integrate SPM-based fabrication and diagnostics is discussed in terms of the development of predictive physical models for the optimization of the fabrication process and possible choices of future SPM-based nanodevices. C1 ELECTROTECH LAB,TSUKUBA,IBARAKI 305,JAPAN. RP Dagata, JA (reprint author), NIST,DIV PRECIS ENGN,GAITHERSBURG,MD 20899, USA. NR 16 TC 7 Z9 7 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0957-4484 J9 NANOTECHNOLOGY JI Nanotechnology PD SEP PY 1997 VL 8 SI 3A BP A3 EP A9 DI 10.1088/0957-4484/8/3A/002 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA XX140 UT WOS:A1997XX14000002 ER PT J AU Germer, TA Asmail, CC Scheer, BW AF Germer, TA Asmail, CC Scheer, BW TI Polarization of out-of-plane scattering from microrough silicon SO OPTICS LETTERS LA English DT Article ID REFLECTANCE-DISTRIBUTION FUNCTION AB The polarization of light scattered by silicon with a small degree of microroughness was measured out of the plane of incidence. First-order vector perturbation theory for scattering from a rough surface predicts the behavior well. The data and the theory show Brewster-like angles where p --> p scattering from surface microroughness vanishes, as well as a deterministic polarization in other directions. C1 VLSI STAND INC,SAN JOSE,CA 95134. RP Germer, TA (reprint author), NATL INST STAND & TECHNOL,OPT TECHNOL DIV,GAITHERSBURG,MD 20899, USA. NR 10 TC 38 Z9 40 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD SEP 1 PY 1997 VL 22 IS 17 BP 1284 EP 1286 DI 10.1364/OL.22.001284 PG 3 WC Optics SC Optics GA XU425 UT WOS:A1997XU42500002 PM 18188214 ER PT J AU Jentschura, UD Soff, G Mohr, PJ AF Jentschura, UD Soff, G Mohr, PJ TI Lamb shift of 3P and 4P states and the determination of alpha SO PHYSICAL REVIEW A LA English DT Article ID ORDER BINDING CORRECTIONS; STRONG COULOMB FIELD; SELF-ENERGY; HYDROGEN AB The fine-structure interval of P states in hydrogenlike systems can be determined theoretically with high precision, because the energy levels of P states are only slightly influenced by the structure of the nucleus. Therefore a measurement of the fine structure may serve as an excellent test of QED in bound systems, or alternatively as a means of determining the fine-structure constant alpha with very high precision. In this paper an improved analytic calculation of higher-order binding corrections to the one-loop self-energy of 3P and 4P states in hydrogenlike systems with a low nuclear charge number Z is presented. The method of calculation has been described earlier by Jentschura and Pachucki [Phys. Rev. A 54, 1853 (1996)], and is applied hereto the excited P states. Because of the more complicated nature of the wave functions and the bound-state poles corresponding to decay of the excited states, the calculations are more complex. Comparison of the analytic results to the extrapolated numerical data for high-Z ions [Mohr and Kim, Phys. Rev. A 45, 2727 (1992)] serves as an independent test of the analytic evaluation. Theoretical values for the Lamb shift of the P states and for the fine-structure splittings are given. C1 NATL INST STAND & TECHNOL, ATOM PHYS DIV, GAITHERSBURG, MD 20899 USA. RP TU DRESDEN, INST THEORET PHYS, MOMMSENSTR 13, D-01062 DRESDEN, GERMANY. NR 29 TC 40 Z9 40 U1 0 U2 2 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 SEP PY 1997 VL 56 IS 3 BP 1739 EP 1755 DI 10.1103/PhysRevA.56.1739 PG 17 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XV840 UT WOS:A1997XV84000014 ER PT J AU Houbiers, M Stoof, HTC Cornell, EA AF Houbiers, M Stoof, HTC Cornell, EA TI Critical temperature of a trapped Bose gas: Mean-field theory and fluctuations SO PHYSICAL REVIEW A LA English DT Article ID COLLECTIVE EXCITATIONS; EINSTEIN CONDENSATION; NUMBER AB We investigate the possibilities of distinguishing the mean-field and fluctuation effects on;the critical temperature of a trapped Bose gas with repulsive interatomic interactions. Since in a direct measurement of the critical temperature as a function of the number of trapped atoms these effects are small compared to the ideal gas results, we propose to observe Bose-Einstein condensation by adiabatically ramping down the trapping frequency. Moreover, analyzing this adiabatic cooling scheme, we show that fluctuation effects can lead to the formation of a Bose-Einstein condensate at frequencies which are much larger than those predicted by the mean-field theory. C1 UNIV COLORADO,JILA,NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. RP Houbiers, M (reprint author), UNIV UTRECHT,INST THEORET PHYS,PRINCETONPLEIN 5,POB 80006,NL-3508 TA UTRECHT,NETHERLANDS. NR 19 TC 39 Z9 40 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD SEP PY 1997 VL 56 IS 3 BP 2041 EP 2045 DI 10.1103/PhysRevA.56.2041 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XV840 UT WOS:A1997XV84000050 ER PT J AU Everitt, BA Salamon, MB Borchers, JA Erwin, RW Rhyne, JJ Park, BJ ODonovan, KV McMorrow, DF Flynn, CP AF Everitt, BA Salamon, MB Borchers, JA Erwin, RW Rhyne, JJ Park, BJ ODonovan, KV McMorrow, DF Flynn, CP TI Helimagnetic structures in epitaxial Nd/Y superlattices and alloys SO PHYSICAL REVIEW B LA English DT Article ID NEODYMIUM AB The complex magnetic structure of Nd exhibits a new magnetic phase when grown epitaxially, either as a stabilized double hexagonal close-packed alloy, or as part of a Nd/Y superlattice. In the alloy and in those superlattices with small Nd/Y ratios, the incommensurate b axis modulated structure exhibited by elemental Nd at T-N = 19.9 K is absent. In its place, incommensurate helimagnetic order, similar to that in dilute yttrium alloys of the heavy lanthanides, appears below approximately 30 K. Evidence for coherent propagation of the magnetic spiral through the Y spacers is observed in some Y-rich superlattices. As the Nd:Y ratio in the superlattices is increased, the b axis modulated phases reappear and coexist with the helical phase. Thick epitaxial Nd films, nevertheless, exhibit only bulklike magnetic structure. We discuss these observations in terms of band structure modifications. C1 NATL INST STAND & TECHNOL, REACTOR DIV, GAITHERSBURG, MD 20899 USA. UNIV MISSOURI, RES REACTOR, COLUMBIA, MO 65211 USA. RISO NATL LAB, DK-4000 ROSKILDE, DENMARK. UNIV ILLINOIS, DEPT PHYS, URBANA, IL 61801 USA. RI McMorrow, Desmond/C-2655-2008 OI McMorrow, Desmond/0000-0002-4947-7788 NR 18 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD SEP 1 PY 1997 VL 56 IS 9 BP 5452 EP 5460 DI 10.1103/PhysRevB.56.5452 PG 9 WC Physics, Condensed Matter SC Physics GA XW942 UT WOS:A1997XW94200070 ER PT J AU Li, WH Chuang, WY Wu, SY Lee, KC Lynn, JW Tsay, HL Yang, HD AF Li, WH Chuang, WY Wu, SY Lee, KC Lynn, JW Tsay, HL Yang, HD TI Superconductivity, magnetic fluctuations, and magnetic order in TbSr2Cu2.69Mo0.31O7 SO PHYSICAL REVIEW B LA English DT Article ID AC-SUSCEPTIBILITY; NEUTRON-SCATTERING; TB; YBA2CU3O7-DELTA; PB2SR2TBCU3O8; DEPENDENCE; FIELD; GD; PR AB Neutron-diffract ion and ac-susceptibility measurements have been performed to study the superconductivity and magnetic order of the Tb spins in polycrystalline TbSr2Cu2.69Mo0.31O7. Superconductivity with an onset temperature at 37 K was observed in the de electrical resistivity and ac-magnetic-susceptibility measurements. A two-step transition to the super-conducting state was seen, as both intragranular and Josephson-like intergranular losses were evident in the out-of phase component of the ac susceptibility. Magnetic correlations between the To spins start developing around 40 K, and the correlation length diverges at T-N-5.4 K with the nearest-neighbor Tb spins aligned antiparallel along all three crystallographic directions. Below 5.4 K, superconductivity and Tb magnetic order coexist. C1 NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. NATL SUN YAT SEN UNIV,DEPT PHYS,KAOHSIUNG 80424,TAIWAN. RP Li, WH (reprint author), NATL CENT UNIV,DEPT PHYS,CHUNGLI 32054,TAIWAN. NR 27 TC 10 Z9 10 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 SEP 1 PY 1997 VL 56 IS 9 BP 5631 EP 5636 DI 10.1103/PhysRevB.56.5631 PG 6 WC Physics, Condensed Matter SC Physics GA XW942 UT WOS:A1997XW94200095 ER PT J AU Hill, RJ Boratav, ON AF Hill, RJ Boratav, ON TI Pressure statistics for locally isotropic turbulence SO PHYSICAL REVIEW E LA English DT Article ID REYNOLDS-NUMBER; SPECTRA AB The pressure structure function D-p(r) and pressure-gradient correlation A(ij)((r) over right arrow) are related to components of the fourth-order velocity structure function D-ijkl((r) over right arrow) on the basis of the Navier-Stokes equation, incompressibility, local homogeneity, and local isotropy. Data from a wind tunnel, as well as numerical simulation, are used to calculate D-p(r) and thereby show that greater Reynolds numbers are needed to observe an inertial range in D-p(r) than in D-ijkl((r) over right arrow). A previous additional supposition relates D-p(r) and A(ij)((r) over right arrow) to the single component D-llll(r). This additional supposition is shown to be inaccurate for calculation of D-p(r) and A(ij)((r) over right arrow). C1 UNIV CALIF IRVINE,DEPT MECH & AEROSP ENGN,IRVINE,CA 92697. RP Hill, RJ (reprint author), NOAA,ERL,ENVIRONM TECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 23 TC 14 Z9 14 U1 1 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 SEP PY 1997 VL 56 IS 3 BP R2363 EP R2366 PN A PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XY129 UT WOS:A1997XY12900007 ER PT J AU Dender, DC Hammar, PR Reich, DH Broholm, C Aeppli, G AF Dender, DC Hammar, PR Reich, DH Broholm, C Aeppli, G TI Direct observation of field-induced incommensurate fluctuations in a one-dimensional S=1/2 antiferromagnet SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC-FIELD; ANTI-FERROMAGNET; EXCITATIONS; SPECTRUM; NEUTRON; CHAINS AB Neutron scattering from copper benzoate, Cu(C6D5COO)(2) . 3D(2)O, provides the first direct experimental evidence for field-dependent incommensurate low energy modes in a one-dimensional spin S = 1/2 antiferromagnet. Soft modes occur for wave vectors (q) over tilde = pi +/- delta (q) over tilde(H), where delta (q) over tilde(H) approximate to 2 pi M(H)/g mu(B) as predicted by Bethe ansatz and spinon descriptions of the S = 1/2 chain. Unexpected was a field-induced energy gap Delta(H) alpha H-alpha, where alpha = 0.65(3) as determined from specific heat measurements. At H = 7 T (g mu(B)H/J = 0.52), the magnitude of the gap varies from 0.06J to 0.3J depending on the orientation of the applied field. C1 NIST, GAITHERSBURG, MD 20899 USA. NEC RES INST, PRINCETON, NJ 08540 USA. RP JOHNS HOPKINS UNIV, DEPT PHYS & ASTRON, BALTIMORE, MD 21218 USA. RI Broholm, Collin/E-8228-2011 OI Broholm, Collin/0000-0002-1569-9892 NR 32 TC 214 Z9 214 U1 2 U2 22 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 SEP 1 PY 1997 VL 79 IS 9 BP 1750 EP 1753 DI 10.1103/PhysRevLett.79.1750 PG 4 WC Physics, Multidisciplinary SC Physics GA XU057 UT WOS:A1997XU05700043 ER PT J AU Spaid, MAA Phelan, FR AF Spaid, MAA Phelan, FR TI Lattice Boltzmann methods for modeling microscale flow in fibrous porous media SO PHYSICS OF FLUIDS LA English DT Article ID NAVIER-STOKES EQUATION; BRINKMAN EQUATION; SIMULATION; VISCOSITY; SURFACE AB A lattice Beltzmann description of fluid flow in heterogeneous porous media is presented which is intended for modelling flow processes which occur in liquid composite molding applications. The lattice Boltzmann method is equivalent to solving a hybrid method of the Stokes and Brinkman equations, with the Brinkman equation being implemented to model flow through porous structures, while the Stokes equation is applied to the open regions outside the porous structures. The Brinkman equation is recovered through a modification of the particle equilibrium distribution function, which reduces the magnitude of momentum at specified lattice sites, while leaving the direction of momentum unchanged. As a test of the new lattice Boltzmann model, steady transverse flow (saturated) through a square array of porous cylinders of elliptical cross section is investigated. Cell permeabilities obtained from the lattice Boltzmann simulations are in excellent agreement with a lubrication model, validating the lattice Boltzmann formulation of the Stokes and Brinkman equations. RP Spaid, MAA (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 22 TC 135 Z9 141 U1 3 U2 20 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD SEP PY 1997 VL 9 IS 9 BP 2468 EP 2474 DI 10.1063/1.869392 PG 7 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA XT861 UT WOS:A1997XT86100004 ER PT J AU Phillips, WD Lucatorto, T AF Phillips, WD Lucatorto, T TI Richard Nathaniel Watts - Obituary SO PHYSICS TODAY LA English DT Item About an Individual RP Phillips, WD (reprint author), NIST,GAITHERSBURG,MD 20899, 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 SEP PY 1997 VL 50 IS 9 BP 100 EP 100 DI 10.1063/1.881924 PG 1 WC Physics, Multidisciplinary SC Physics GA XU771 UT WOS:A1997XU77100031 ER PT J AU Martineu, P Juniper, SK Fisher, CR Massoth, GJ AF Martineu, P Juniper, SK Fisher, CR Massoth, GJ TI Sulfide binding in the body fluids of hydrothermal vent alvinellid polychaetes SO PHYSIOLOGICAL ZOOLOGY LA English DT Article ID WORM RIFTIA-PACHYPTILA; DE-FUCA RIDGE; TUBE-WORM; CHEMOAUTOTROPHIC SYMBIONTS; CALYPTOGENA-MAGNIFICA; HEMOGLOBIN; BLOOD; VESTIMENTIFERA; BIOLOGY; PACIFIC AB Dissolved H2S is a major environmental factor in hydrothermal vent ecosystems. In a study of adaptations to sulfide by alvinellid polychaetes, the sulfide-binding capacity of body fluids was examined in Paralvinella palmiformis from northeast Pacific ridges and Alvinella species from the East Pacific Rise, Sulfide concentrations in vascular blood and coelomic fluid of freshly collected animals were notably variable. Separation of P. palmiformis body-fluid components revealed that: most sulfide (ca, 77%) was accumulated in the dissolved fraction. In P. palmiformis, both vascular blood and coelomic fluid could reversibly bind sulfide in vitro with a low affinity, saturating only at high dialysate concentrations (ca. 2 mmol L-1). No sulfide-binding activity was observed in the vascular blood from Alvinella species, A dissolved protein component of greater than 90 kDa appears to be involved in sulfide binding in Paralvinella, probably a vascular extracellular high-molecular-weight hemoglobin. Some sulfide may also adsorb onto a 15.38-kDa intracellular hemoglobin present in the coelomic erythrocyte fraction, In the absence of epibiotic bacteria, Paralvinella body fluids may function as a sulfide buffer To protect tissues from deleterious effects of sulfide exposure. C1 UNIV QUEBEC, CTR RECH GEOCHIM ISOTOP & GEOCHRONOL, MONTREAL, PQ H3C 3P8, CANADA. PENN STATE UNIV, DEPT BIOL, UNIVERSITY PK, PA 16802 USA. NOAA, PACIFIC MARINE ENVIRONM LAB, SEATTLE, WA 98115 USA. RP Martineu, P (reprint author), UNIV QUEBEC, DEPT BIOL, CP 8888, SUCCURSALE CTR VILLE, MONTREAL, PQ H3C 3P8, CANADA. RI Fisher, Charles/H-7912-2012 NR 46 TC 15 Z9 16 U1 1 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0031-935X J9 PHYSIOL ZOOL JI Physiol. Zool. PD SEP-OCT PY 1997 VL 70 IS 5 BP 578 EP 588 DI 10.1086/515864 PG 11 WC Physiology; Zoology SC Physiology; Zoology GA XT866 UT WOS:A1997XT86600010 PM 9279925 ER PT J AU Baldocchi, D AF Baldocchi, D TI Measuring and modelling carbon dioxide and water vapour exchange over a temperate broad-leaved forest during the 1995 summer drought SO PLANT CELL AND ENVIRONMENT LA English DT Article DE carbon dioxide; drought; evaporation; net ecosystem carbon exchange; photosynthesis; stomatal conductance; temperate hardwood forest ID OAK-HICKORY FOREST; DECIDUOUS FOREST; STOMATAL CONDUCTANCE; GAS-EXCHANGE; LEAF PHOTOSYNTHESIS; NET PHOTOSYNTHESIS; CO2 ASSIMILATION; EDDY-CORRELATION; BOUNDARY-LAYER; ABSCISIC-ACID AB Forests in the south-eastern United States experienced a prolonged dry spell anal above-normal temperatures during the 1995 growing season. During this episode, nearly continuous, eddy covariance measurements of carbon dioxide and water vapour fluxes were acquired over a temperate, hardwood forest. These data are used to examine how environmental factors and accumulating soil moisture deficits affected the diurnal pattern and magnitude of canopy-scale carbon dioxide and water vapour fluxes. The field data are also used to test an integrative leaf-to-canopy scaling model (CANOAK), which uses micrometeorological and physiological theory, to calculate mass and energy fluxes. When soil moisture was ample in the spring, peak rates of net ecosystem CO2 exchange (N-E) occurred around midday and exceeded 20 mu mol m(-2) s(-1). Rates of N-E were near optimal when air temperature ranged between 22 and 25 degrees C. The accumulation of soil moisture deficits and a co-occurrence of high temperatures caused peak rates of daytime carbon dioxide uptake to occur earlier in the morning. High air temperatures and soil moisture deficits were also correlated with a dramatic reduction in the magnitude of N-E. On average, the magnitude of N-E decreased from 20 to 7 mu mol m(-2) s(-1) as air temperature increased from 24 to 30 degrees C and the soil dried. The CANAOK model yielded accurate estimates of canopy-scale carbon dioxide and water vapour fluxes when the forest had an ample supply of soil moisture. During the drought and heat spell, a cumulative drought index was needed to adjust the proportionality constant of the stomatal conductance model to yield accurate estimates of canopy CO2 exchange. The adoption of the drought index also enabled the CANOAK model to give improved estimates of evaporation until midday. On the other hand, the scheme failed to yield accurate estimates of evaporation during the afternoon. RP Baldocchi, D (reprint author), NOAA,ATMOSPHER TURBULENCE & DIFFUS DIV,POB 2456,OAK RIDGE,TN 37831, USA. RI Baldocchi, Dennis/A-1625-2009 OI Baldocchi, Dennis/0000-0003-3496-4919 NR 86 TC 213 Z9 229 U1 4 U2 39 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0140-7791 J9 PLANT CELL ENVIRON JI Plant Cell Environ. PD SEP PY 1997 VL 20 IS 9 BP 1108 EP 1122 DI 10.1046/j.1365-3040.1997.d01-147.x PG 15 WC Plant Sciences SC Plant Sciences GA XX606 UT WOS:A1997XX60600003 ER PT J AU Bengtson, JL Stewart, BS AF Bengtson, JL Stewart, BS TI Diving patterns of a Ross seal (Ommatophoca rossii) near the eastern coast of the Antarctic Peninsula SO POLAR BIOLOGY LA English DT Article ID AEROBIC DIVE LIMIT; WEDDELL SEALS; OXYGEN STORES AB In January 1987 we documented the diving patterns of a female Ross seal (Ommatophoca rossii) in the marginal pack-ice zone near the eastern coast of the Antarctic Peninsula for 2 days using a microprocessor-based time-depth recorder. The seal hauled out during the day and dived continually when in the water at night. Dives averaged 110 m deep and 6.4 min long; the deepest dive was 212 m and the longest 9.8 min. Dives were deepest near twilight and shallowest at night; this pattern suggests that the seal's prey, presumably midwater squid and fish, may have been making vertical migrations or changing predator-avoidance behavior in response to diel light patterns. The dives of this Ross seal were substantially deeper, on average, than those of crabeater seals (Lobodon carcinophagus), which forage in the same areas on Antarctic krill (Euphausia superba). C1 HUBBS SEA WORLD RES INST,SAN DIEGO,CA 92109. RP Bengtson, JL (reprint author), NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,NATL MARINE MAMMAL LAB,SEATTLE,WA 98115, USA. NR 27 TC 19 Z9 21 U1 0 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0722-4060 J9 POLAR BIOL JI Polar Biol. PD SEP PY 1997 VL 18 IS 3 BP 214 EP 218 DI 10.1007/s003000050178 PG 5 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA XR398 UT WOS:A1997XR39800007 ER PT J AU Bur, AJ Thomas, CL AF Bur, AJ Thomas, CL TI Fluorescence monitoring of polymer infection molding: Model development SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers ID VOLUME; RELAXATION; VISCOSITY AB We have developed models to describe the behavior of an optical fiber sensor which was used to detect fluorescence from a polymer resin during the cooling phase of injection molding. The optical fiber sensor was positioned at the wall of the mold cavity by using the ejector pin channel as access to the cavity. The sources of fluorescence were dyes, which were chosen because of their sensitivity to temperature and which were mixed with the resin at dopant concentrations (parts per million by weight). The behaviors of a molecular rotor dye, dimethylamino diphenyl hexatriene, doped into polyethylene, and an excimer producing dye, bis-(pyrene) propane, doped into polystyrene were the subjects of the modeling calculations. The models consist of two modules: (a) a solution to the thermal diffusion equation for the resin cooling in the mold and (b) using temperature/time profiles and, In the case of polyethylene, crystallinity/time profiles obtained from the thermal diffusion equation, fluorescence intensity as a function of time was computed. Factors incorporated in the models are: adiabatic heating and cooling, light scattering due to microcrystals of polyethylene. crystallization kinetics, temperature and pressure shift factors for viscoelastic relaxation near the glass transition temperature of polystyrene, and the thermal resistance at the resin/mold interface. C1 UNIV UTAH,DEPT MECH ENGN,SALT LAKE CITY,UT 84112. RP Bur, AJ (reprint author), NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 21 TC 13 Z9 15 U1 1 U2 3 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1430 EP 1441 DI 10.1002/pen.11790 PG 12 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600002 ER PT J AU Gusler, GM McKenna, GB AF Gusler, GM McKenna, GB TI The craze initiation response of a polystyrene and a styrene-acrylonitrile copolymer during physical aging SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers ID CREEP-RUPTURE BEHAVIOR; GLASSY-POLYMERS; POLYCARBONATE; PMMA AB The influence of structural recovery or physical aging on the craze initiation of amorphous polystyrene and a styrene-acrylonitrile copolymer has been examined in two states of stress/deformation and at different temperatures. Studies of craze initiation in equibiaxial creep were performed using a ''bubble'' inflation test geometry while uniaxial elongation in stress relaxation conditions was studied by bending the specimen over a variable radius of a curvature test jig. All tests were performed by aging the specimen and testing it at the same temperature subsequent to a quench from above the glass transition to below it. The results are compared with expectations from three craze models: Sternstein and Ongchin (1), Argon (2), and Kambour (3). The results are most consistent with the model of Kambour, but discrepancies arise because, e.g., the impact of aging on the stress for crazing in the equibiaxial tests is different for the polystyrene than for the styrene-acrylonitrile copolymer. The results also suggest that there are two regimes of behavior for craze initiation under equibiaxial stresses, a behavior not manifested in the uniaxidal stress relaxation experiments. C1 NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 21 TC 9 Z9 9 U1 0 U2 3 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1442 EP 1448 DI 10.1002/pen.11791 PG 7 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600003 ER PT J AU Jackson, CL Sung, L Han, CC AF Jackson, CL Sung, L Han, CC TI Evolution of phase morphology in compatibilized polymer blends at constant quench depths: Complementary studies by light scattering and transmission electron microscopy SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers ID COPOLYMER-HOMOPOLYMER BLENDS; ANGLE NEUTRON-SCATTERING; BLOCK-COPOLYMER; SPINODAL DECOMPOSITION; DIBLOCK COPOLYMER; SEPARATION KINETICS; MICELLE FORMATION; MOLECULAR-WEIGHT; BINARY MIXTURE; DYNAMICS AB The effect of added block copolymer on the phase separation and morphology evolution in a partially miscible blend of polystyrene and polybutadiene near the critical composition is studied by temperature jump light scattering (TJLS) and transmission electron microscopy (TEM). As block copolymer is added, the phase boundary is shifted to lower temperatures and the phase separation process is slowed dramatically. Since the quench depth greatly affects the rate of phase separation in any blend system, we have used equivalent quench depths by adjusting for the shift in the phase boundary as block copolymer is added. The morphology evolution of these ternary blends was studied by preparing TEM specimens at equivalent shallow quench depths (Delta T = 1.6 degrees C) and allowing each blend mixture to coarsen for the time required to reach a specific constant size, or q-value, using the TJLS data on the kinetics of phase separation. The q-range selected was q similar to 0.003-0.005 nm(-1), which corresponds to a spacing of 1-2 mu m in real space. The combination of light scattering and microscopy techniques more rigorously describes the compatibilization process in these complex ternary systems. RP Jackson, CL (reprint author), NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 56 TC 15 Z9 15 U1 1 U2 3 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1449 EP 1458 DI 10.1002/pen.11792 PG 10 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600004 ER PT J AU Beckmann, J McKenna, GB Landes, BG Bank, DH Bubeck, RA AF Beckmann, J McKenna, GB Landes, BG Bank, DH Bubeck, RA TI Physical aging kinetics of syndiotactic polystyrene as determined from creep behavior SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers ID SEMI-CRYSTALLINE POLYMERS; MECHANICAL-BEHAVIOR; SEMICRYSTALLINE POLYMERS AB Creep experiments in uniaxial extension have been performed to explore the kinetics of the physical aging process in semicrystalline syndiotactic polystyrene (sPS) having two processing histories. Classical time-aging time superposition behavior was found for both materials at temperatures from 70 to 95 degrees C, with the shift rate mu decreasing as temperature was increased. Virtually no aging was seen at 95 degrees C, the DSC determined glass transition, T-g. This behavior was atypical for a semicrystalline polymer and reminiscent of the behavior of glassy amorphous thermoplastics. Some evidence for a separate crystalline aging mechanism > T-g, which manifests itself as only vertical shifts without timescale shifts, is seen in experiments at T > 100 degrees C. Finally, the two different materials age differently, suggesting that some control of aging can be obtained by altering processing conditions or morphology. C1 NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899. DOW CHEM CO USA,MIDLAND,MI 48674. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 11 TC 20 Z9 20 U1 3 U2 11 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1459 EP 1468 DI 10.1002/pen.11793 PG 10 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600005 ER PT J AU Colucci, DM OConnell, PA McKenna, GB AF Colucci, DM OConnell, PA McKenna, GB TI Stress relaxation experiments in polycarbonate: A comparison of volume changes for two commercial grades SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers ID STRAIN AB Stress relaxation experiments were performed on two grades of polycarbonate at room temperature. The tests were performed in uniaxial extension and compression at deformations from the small strain, linear viscoelastic regime to the highly nonlinear viscoelastic regime just below yield. Simultaneous to the control of axial strain, both stress and lateral strain were measured, the latter providing the volume change for the samples. The volume change measurements in tension show initial dilatation of the samples followed by a volume relaxation that at the largest strains in one grade of polycarbonate leads to densities greater than those of the undeformed sample. In the case of the compression measurements, the volume decreases upon deformation, but, rather than relaxing back towards the undeformed volume, the samples continuously densify. The differences in the tensile dilatation for the two grades of polycarbonate suggest that the volume behavior may be related to the propensity to yield vs. fracture. C1 NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 20 TC 52 Z9 52 U1 2 U2 4 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1469 EP 1474 DI 10.1002/pen.11794 PG 6 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600006 ER PT J AU Hu, RZ Lambert, WS Barnes, JD AF Hu, RZ Lambert, WS Barnes, JD TI Structure-property correlations in stretched LLDPE films using oblique incidence small-angle X-ray scattering SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers AB This paper demonstrates the use of oblique incidence small-angle X-ray scattering (SAXS) to characterize microstructure in linear low-density polyethylene films subjected to biaxial deformation in a TM Long stretcher. Differences in tear strength and impact properties were found when two different deformation temperatures were used. SAXS was used to characterize the nanometer scale microstructure of these films. Since the microstructure was expected to be anisotropic, SAXS data were collected in normal incidence, T (transverse) oblique incidence and M (reference direction) oblique incidence. The sections through the three-dimensional SAXS pattern collected in these three orientations are combined to provide clues to the nature of the complete 3-D SAXS pattern, which can be interpreted to characterize the changes wrought by deformation. C1 WR GRACE & CO CONN,CRYOVAC DIV,DUNCAN,SC 29334. NIST,POLYMER STRUCT & MECH GRP,GAITHERSBURG,MD 20899. RP Hu, RZ (reprint author), WR GRACE & CO CONN,WASHINGTON RES CTR,COLUMBIA,MD 21044, USA. NR 9 TC 1 Z9 1 U1 0 U2 2 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1475 EP 1479 DI 10.1002/pen.11795 PG 5 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600007 ER PT J AU Barnes, JD McKenna, GB Landes, BG Bubeck, RA Bank, D AF Barnes, JD McKenna, GB Landes, BG Bubeck, RA Bank, D TI Morphology of syndiotactic polystyrene as examined by small-angle X-ray scattering SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers ID FORM AB Small Angle X-Ray scattering (SAXS) studies have been carried out on injection molded syndiotactic polystyrene (SPS) at room temperature and at elevated temperatures up to 290 degrees C. Features indicating lamellar crystallinity were weak or entirely absent at room temperature, becoming increasingly Intense above the glass transition temperature (T-g) for this material. A background scattering whose intensity was roughly proportional to q(-2), where q is the scattering momentum transfer, was present throughout the temperature range. We suggest that these results indicate that SPS materials formed in this way are three-phase systems, with an amorphous phase, a crystalline phase, and a grain boundary phase. C1 DOW CHEM CO USA,MIDLAND,MI 48674. RP Barnes, JD (reprint author), NIST,DIV POLYMER,STRUCT & MECH GRP,GAITHERSBURG,MD 20899, USA. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 11 TC 15 Z9 16 U1 1 U2 4 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1480 EP 1484 DI 10.1002/pen.11796 PG 5 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600008 ER PT J AU OConnell, PA McKenna, GB AF OConnell, PA McKenna, GB TI Large deformation response of polycarbonate: Time-temperature, time-aging time, and time-strain superposition SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers ID RELAXATION; POLYMERS; ENTHALPY; GLASSES; RANGE AB Data are presented from tests of the stress relaxation response of a polycarbonate under torsional deformations. Tests were performed on samples over a range of strains from 0.0025 to 0.08, temperatures from 30 to 135 degrees C and aging times from 1800 to 64,800 s. Individual data sets at each strain, temperature and aging time could be described using a stretched exponential form relaxation function, and time-aging time superposition was found to be applicable to the data under all test conditions. The double logarithmic aging time shift rate, mu, was found to vary significantly with both temperature and strain. Over the range of temperatures studied the data could be superimposed using conventional time-temperature superposition. However, the master curve was found not to be described by a stretched exponential Function. For strains up to 0.07, the data at each temperature could also be superimposed to form a master curve following the principle of time-strain superposition. Interestingly, the master curves found from time-strain and time-temperature superposition did not have the same form. In both the time-aging time and time-temperature superposition analyses it was found that the application of vertical shifts was required for superposition of data. RP OConnell, PA (reprint author), NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 27 TC 102 Z9 106 U1 0 U2 12 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1485 EP 1495 DI 10.1002/pen.11797 PG 11 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600009 ER PT J AU Nyden, MR Coley, TR Mumby, S AF Nyden, MR Coley, TR Mumby, S TI Applications of molecular dynamics to the study of thermal degradation in aromatic polymers .1. Polystyrene SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers AB This paper reports recent progress in the development of a generic molecular dynamics model that accounts for the major chemical reactions involved in the thermal degradation of polymers. The strategy employed in the design of the most recent version of this model was to interface our code for performing reactive dynamics on simple vinyl polymers with a commercial molecular dynamics package (Discover 95). The expanded range of applicability of the integrated model is illustrated by applying it to the study of thermal degradation in atactic polystyrene. C1 MOL SIMULAT,SAN DIEGO,CA 92122. RP Nyden, MR (reprint author), NATL INST STAND & TECHNOL,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899, USA. NR 9 TC 18 Z9 18 U1 1 U2 2 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1496 EP 1500 DI 10.1002/pen.11798 PG 5 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600010 ER PT J AU Riley, DJ Gungor, A Srinivasan, SA Sankarapandian, M Tchatchoua, C Muggli, MW Ward, TC McGrath, JE Kashiwagi, T AF Riley, DJ Gungor, A Srinivasan, SA Sankarapandian, M Tchatchoua, C Muggli, MW Ward, TC McGrath, JE Kashiwagi, T TI Synthesis and characterization of flame resistant poly(arylene ether)s SO POLYMER ENGINEERING AND SCIENCE LA English DT Article; Proceedings Paper CT Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers AB Hydrolytically stable phosphorus-containing monomers, such as 4,4'-bis(fluorophenyl)methylphosphine oxide (BFPMPO), 4,4'-bis(hydroxyphenyl)methylphosphine oxide (BOHPMPO), and 4,4-bis(hydroxyphenyl)phenylphosphine oxide (BOHPPO), were synthesized and used in nucleophilic aromatic substitution polycondensation to prepare poly(arylene ether phosphine oxide) engineering thermoplastics. The synthesis and characterization of these novel polymers are described. It was determined that by incorporating the phosphine oxide moiety into the polymer backbone, certain properties of the resulting poly(arylene ether) were substantially improved, such as an increase in T-g, thermal stability in air, modulus, and char yield compared with control poly(arylene ether sulfone)s. The high char yields obtained for these polymers in air along with observed intumescence indicates that these materials have improved fire resistance. Preliminary cone calorimetry measurements support this conclusion. C1 VIRGINIA POLYTECH INST & STATE UNIV,DEPT CHEM,BLACKSBURG,VA 24061. NSF,CTR SCI & TECHNOL HIGH PERFORMANCE POLYMER ADHES,BLACKSBURG,VA 24061. NATL INST STAND & TECHNOL,BLDG & FIRE RES LAB,GAITHERSBURG,MD 20899. NR 25 TC 35 Z9 35 U1 3 U2 9 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1997 VL 37 IS 9 BP 1501 EP 1511 DI 10.1002/pen.11799 PG 11 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA XY596 UT WOS:A1997XY59600011 ER PT J AU Estler, WT Evans, CJ Shao, LZ AF Estler, WT Evans, CJ Shao, LZ TI Uncertainty estimation for multiposition form error metrology SO PRECISION ENGINEERING-JOURNAL OF THE AMERICAN SOCIETY FOR PRECISION ENGINEERING LA English DT Article DE difference techniques; dimensional metrology; error separation; multistep methods; roundness; spindle errors; optical figure metrology ID ACCURACY AB We analyze a general multiposition comparator measurement procedure that leads to partial removal of artifact error for a class of problems including roundness metrology, measurement of radial error motions of precision spindles, and figure error metrology of high-accuracy optical components. Using spindle radial error motion as an explicit example, we present a detailed analysis of a complete test with N orientations of a test ball with respect to the spindle. In particular, we show that (1) all components of the ball roundness error average to zero except those with frequencies of kN cycles/revolution, where k is a positive integer; and (2) the combined standard uncertainty of the measurement is proportional to 1/root N. We then show how a complete set of measurements for an N-position test can be synthesized from only two measurements, and we derive a general expression for the combined standard uncertainty as a function of the number of positions n (2 less than or equal to n less than or equal to N) actually measured in an N-position test. This uncertainty can serve as a useful guide to measurement design, involving trade-offs between multiple setup cost and complexity and required levels of angular harmonic resolution and combined standard measurement uncertainty. Published by Elsevier Science Inc. C1 NIST, Div Precis Engn, Gaithersburg, MD 20899 USA. RP Estler, WT (reprint author), NIST, Div Precis Engn, Metrol B113, Gaithersburg, MD 20899 USA. NR 15 TC 24 Z9 25 U1 4 U2 12 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0141-6359 J9 PRECIS ENG JI Precis. Eng.-J. Am. Soc. Precis. Eng. PD SEP-DEC PY 1997 VL 21 IS 2-3 BP 72 EP 82 PG 11 WC Engineering, Multidisciplinary; Engineering, Manufacturing; Nanoscience & Nanotechnology; Instruments & Instrumentation SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation GA YX089 UT WOS:000072005300002 ER PT J AU Holloway, CL Doviak, RJ Cohn, SA AF Holloway, CL Doviak, RJ Cohn, SA TI Cross correlations of fields scattered by horizontally anisotropic refractive index irregularities SO RADIO SCIENCE LA English DT Article AB In this paper we present an analytic expression for the cross-correlation function of signals received by spaced antennas for scattering from an atmosphere with horizontally and/or vertically anisotropic scattering irregularities. We demonstrate that our expression is equivalent to the one Briggs [1984] obtained through heuristic arguments; we also show how the parameters in Briggs's expression are related to parameters that describe (1) the orientation, shape, and size of the scattering irregularities; (2) the turbulent flow; and (3) the radar. Finally, we introduce an alternative approach (different from Briggs's full correlation analysis) for estimating horizontal winds and turbulence. C1 NCAR,ATMOSPHER TECHNOL DIV,BOULDER,CO 80301. NOAA,NATL SEVERE STORMS LAB,NORMAN,OK 73069. RP Holloway, CL (reprint author), NATL TELECOMMUN & INFORMAT ADM,INST TELECOMMUN SCI,325 BROADWAY,BOULDER,CO 80303, USA. NR 17 TC 18 Z9 18 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 SEP-OCT PY 1997 VL 32 IS 5 BP 1911 EP 1920 DI 10.1029/97RS00715 PG 10 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA XY809 UT WOS:A1997XY80900016 ER PT J AU Conkright, RO McNamara, LF AF Conkright, RO McNamara, LF TI Quality control of automatically scaled vertical incidence ionogram data SO RADIO SCIENCE LA English DT Article; Proceedings Paper CT 8th International Ionospheric Effects Symposium (IES-96) CY MAY 07-09, 1996 CL ALEXANDRIA, VA SP USN, Off Naval Res, USAF, Phillips Lab, USA, CECOM, USN, Naval C2 Ocean Surveillance Ctr, RDT&E Div, Voice America, Fed Commun Commiss AB Software procedures are described for the routine scanning of data sets from automatically scaled vertical incidence ionograms, with a view to identifying ionograms which have been incorrectly scaled. Such procedures have been made necessary by the increasing use of real-time ionospheric data in operational systems and by the increasing flow of such data into the U.S. National Geophysical Data Center (NGDC), which have made the required data-scanning functions overwhelming for a human operator. The procedures will detect pathological data sets and prevent them from being passed on to the operational system or to NGDC databases, as well as indicating unusual ionospheric conditions and possibly the need for modifications of the automated procedures. Particular reference is made to the SAO (standard ARTIST output) files created by the University of Massachusetts Lowell program ADEP (ARTIST display and editing program) and corresponding to ionograms obtained using a Digisonde and scaled in real time by ARTIST (automatic real-time ionogram scaling with true-height). These files were chosen because of their ready availability at NGDC and because they cover a wide range of latitudes, seasons, and ionospheric conditions. Similar procedures can readily be developed for other ionogram data sets. The basic change would be to the function which reads in the data, although experience will probably lead to the inclusion of procedures to counter idiosyncrasies of the ionogram scaling procedures, such as have been found with ARTIST. RP Conkright, RO (reprint author), NOAA,NATL GEOPHYS DATA CTR,MAIL CODE E-GC2,3100 MARINE ST,BOULDER,CO 80302, USA. NR 8 TC 2 Z9 2 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 SEP-OCT PY 1997 VL 32 IS 5 BP 1997 EP 2002 DI 10.1029/97RS01031 PG 6 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA XY809 UT WOS:A1997XY80900024 ER PT J AU Watts, RN Liang, S Levine, ZH Lucatorto, TB Polack, F Scheinfein, MR AF Watts, RN Liang, S Levine, ZH Lucatorto, TB Polack, F Scheinfein, MR TI A transmission x-ray microscope based on secondary-electron imaging SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PHOTOELECTRON MICROSCOPE; ZONE-PLATE; RESOLUTION; CONTRAST; SPECTROMICROSCOPY; SPECIMENS; EMISSION; LENSES; FIELD; UV AB A design for a transmission x-ray microscope with 20 nm transverse spatial resolution is presented. The microscope, which is based on the electron-optical imaging of the photoemitted electrons from an x-ray shadowgraph, consists of a transmission x-ray photocathode coupled to a photoelectron emission microscope (PEEM-also called a PEM for photoelectron microscope). Unlike the conventional PEEM, which produces a surface map of photoelectron yield. this microscope can provide in-formation on the subsurface properties of thin samples. The analysis of the microscope's electron-optical performance is based on the evaluation of Gaussian focusing properties and third-order aberration coefficients computed using several complementary methods. The electron optical properties of the microscope are examined with an emphasis on issues affecting overall performance and achieving the best possible resolution. Preliminary experimental results using a cesium iodide photocathode are shown. (C) 1997 American Institute of Physics. C1 CTR UNIV PARIS SUD,LURE,F-94120 ORSAY,FRANCE. ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. RP Watts, RN (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 36 TC 22 Z9 22 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD SEP PY 1997 VL 68 IS 9 BP 3464 EP 3476 DI 10.1063/1.1148309 PG 13 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA XX257 UT WOS:A1997XX25700027 ER PT J AU Bernik, S AF Bernik, S TI Synthesis and phase relations of the 110 K superconducting 2223 phase in the Bi-Pb-Sr-Ca-Cu-O system SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID HIGH-TC PHASE; TEMPERATURE; BI2-XPBXSR2CA2CU3OY; BI2SR2CA2CU3O10; DIAGRAMS; REGION AB The influence of starting composition, especially the Bi:Pb ratio, on the formation of the 110 K superconducting 2223 phase was investigated. Compositional limits for 'pure' 2223 have been preliminarily determined in terms of Pb versus Bi + Pb. In samples with nominal composition Bi2+d-xPbxSr2Ca2Cu3Oz (d = 0), 2223 forms when x greater than or equal to 0.2. The 2223 phase coexists with 2212 in the range 0.2 less than or equal to x less than or equal to 0.4 (i.e. with 10-20 mol% Si replaced by Pb) after annealing at 855 degrees C for 100 h. Some (Ca,Sr)(2)CuO3 is also found. The 2223 phase was the only superconducting phase in samples where x > 0.4; (Pb,Bi)(1.4)(Sr,Ca)(3)Cu0.77Oz was also found in these samples. 'Pure' 2223 was obtained in samples with nominal composition Bi2+d-xPbxSr2Ca2Cu3Oz when x = 0.4 and d = 0.1, 0.2, 0.3. The 2223 phase can be formed from starting compositions with less than 10 mol% Bi replaced by Pb, provided (Bi + Pb) > 2. The 2201 phase coexists with 2223 when (Bi + Pb) > 2.3 and Pb > 0.2. C1 JOZEF STEFAN INST,DIV CERAM,LJUBLJANA 1000,SLOVENIA. RP Bernik, S (reprint author), NIST,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 27 TC 20 Z9 20 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD SEP PY 1997 VL 10 IS 9 BP 671 EP 677 DI 10.1088/0953-2048/10/9/007 PG 7 WC Physics, Applied; Physics, Condensed Matter SC Physics GA XW080 UT WOS:A1997XW08000007 ER PT J AU Powell, CJ AF Powell, CJ TI Energy calibration of x-ray photoelectron spectrometers .2. Issues in peak location and comparison of methods SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE XPS; x-ray photoelectron spectroscopy; energy calibration; peak location ID CORE-LEVEL SHIFTS; SURFACE-ANALYSIS; ELECTRON SPECTROMETERS; XPS; PHOTOEMISSION; ESCA; COMMITTEE; METALS; AES; AG AB An analysis is presented of issues involved in peak location for the calibration of the binding energy (BE) scales of x-ray photoelectron spectrometers. These issues include the effects of peak asymmetry, the surface core-level shift, and the avoidance of a sloping background when fitting spectra for energy calibration purposes. Examples of uncertainty budgets for BE measurements are then presented in which illustrative values are shown for the repeatability standard deviation (for repeated BE measurements of the same calibration peak), the expanded uncertainty (at the 95% confidence level) for BE measurements following calibrations based on different numbers of peak measurements, and the tolerance for BE-scale drift and non-linearity for two chosen values (+/-0.1 and +/-0.2 eV) of the total expanded uncertainty for a BE measurement (at the 95% confidence level). It is recommended that a user prepare an uncertainty budget of this type to show clearly the sources of random and systematic error in BE measurements following a calibration. The reference data published by the UK National Physical Laboratory for BE-scale calibration were obtained from fits with a quadratic function to a group of points comprising the top 5% of each peak. Most commercial x-ray photoelectron spectrometers have software available for spectrum synthesis, and we consider here the use of the commonly available Lorentzian, Gaussian, and asymmetric Gaussian functions for peak location. Illustrative fits with Cu 2p(3/2) spectra (measured with ummonochromated Al x-rays) showed that comparable accuracy and precision could be obtained with Lorentzian and Gaussian functions as with the quadratic-equation method when different fractions of the peak were fitted. For this asymmetrical line, the asymmetric Gaussian function allowed better accuracy and precision to be obtained with a greater fraction of the line than was possible with the symmetrical functions. (C) 1997 by John Wiley & Sons, Ltd. RP Powell, CJ (reprint author), NATL INST STAND & TECHNOL,SURFACE & MICROANAL SCI DIV,GAITHERSBURG,MD 20899, USA. NR 27 TC 11 Z9 11 U1 1 U2 8 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD SEP PY 1997 VL 25 IS 10 BP 777 EP 787 DI 10.1002/(SICI)1096-9918(199709)25:10<777::AID-SIA299>3.3.CO;2-V PG 11 WC Chemistry, Physical SC Chemistry GA XW809 UT WOS:A1997XW80900006 ER PT J AU Nho, EY LeCloarec, MF Ardouin, B Ramonet, M AF Nho, EY LeCloarec, MF Ardouin, B Ramonet, M TI Po-210, an atmospheric tracer of long-range transport of volcanic plumes SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID SURFACE AIR; PB-210; ORIGINS; RN-222; RADON AB With the aim of testing the ability of Po-210 to be a tracer of volcanic aerosol plumes, we collected air samples during an oceanographic cruise around the Indonesian are and measured the radioactivity of Po-210. Owing to the atmospheric circulation pattern and geographical distribution of Po-210 sources around the sampling site, the origin of Po-210 Of th, samples could be determined by calculating 5-day backward air mass trajectories. It is shown that the signature of Po-210 originating from volcanic emissions is distinct from that of Rn-222 decay, even though these processes are the 2 major sources of atmospheric Po-210. Moreover, the proportion of Po-210 in a given air parcel is conservative during the transport: as other aerosols, Po-210 aerosols are very sensitive to the atmospheric removal processes and the production and the loss of Po-210 by radio decay within an air parcel is negligible. Our results confirm that Po-210 is a good tracer for aerosols emitted by volcanoes. C1 CEA,CNRS,LAB MIXTE,CTR FAIBLES RADIOACT,F-91190 GIF SUR YVETTE,FRANCE. NOAA,CLIMATE MONITORING & DIAGNOST LAB,BOULDER,CO 80303. NR 30 TC 11 Z9 11 U1 1 U2 7 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD SEP PY 1997 VL 49 IS 4 BP 429 EP 438 DI 10.1034/j.1600-0889.49.issue4.8.x PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XW205 UT WOS:A1997XW20500008 ER PT J AU Silin, V Plant, A AF Silin, V Plant, A TI Biotechnological applications of surface plasmon resonance SO TRENDS IN BIOTECHNOLOGY LA English DT Article ID SUPPORTED LIPID-MEMBRANES; RECOGNITION REACTIONS; GOLD SURFACES; MICROSCOPY; BILAYERS; SPECTROSCOPY; MONOLAYERS; ADSORPTION; ATTACHMENT; KINETICS AB The surface plasmon resonance technique allows direct, real-time kinetic measurements of the interaction of unlabelled biological molecules at surfaces. After a brief discussion of the principles of surface plasmon resonance, we review its application to the nonspecific adsorption of protein, the formation of phospholipid bilayers, membrane-protein interactions and DNA hybridization. The morphological studies of the biological surfaces using surface plasmon resonance microscopy and the potential of the surface plasmon resonance to measure the dynamics of surface layer heterogeneity are discussed. C1 GEORGETOWN UNIV, DEPT CHEM, WASHINGTON, DC 20057 USA. RP Silin, V (reprint author), NATL INST STAND & TECHNOL, DIV BIOTECHNOL, GAITHERSBURG, MD 20899 USA. NR 38 TC 77 Z9 78 U1 1 U2 10 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0167-7799 J9 TRENDS BIOTECHNOL JI Trends Biotechnol. PD SEP PY 1997 VL 15 IS 9 BP 353 EP 359 DI 10.1016/S0167-7799(97)01085-8 PG 7 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA XU046 UT WOS:A1997XU04600008 ER PT J AU Penn, DR Clark, CW Powell, CJ Fulop, T Tanuma, S AF Penn, DR Clark, CW Powell, CJ Fulop, T Tanuma, S TI Theory of the cross sections for inelastic scattering of electrons by core level excitations in solids SO ULTRAMICROSCOPY LA English DT Article ID ENERGY-LOSS SPECTROSCOPY; SHELL IONIZATION; K-SHELL; CHARGED-PARTICLES; COLLISIONS; ATOMS; EELS AB A calculation of cross sections for the inelastic scattering of electrons from core levels is carried out based on a model in which core level electrons are excited into a free-electron-like band state. A simplified model is also developed that assumes oscillator strengths appropriate to band-to-band excitations in solids. The results for Al L-23 and Mo M-45 cross sections are compared with a number of previous calculations. These previous calculations include. (a) the constant-oscillator-strength model, (b) the Rez model (based on excitations to atomic-like states), and (c) the semi-empirical hydrogenic model proposed by Egerton. We have incorporated optical data into all of the models considered in this paper with the exception of Egerton's. Calculations are presented for incident electron energies of 100, 200 and 500 keV, collection angles of 1-41 mrad, and energy collection windows of 20-200 eV. Comparison is also made with experiment where possible and reasonable agreement is found. C1 CHALMERS UNIV TECHNOL,SCH ELECT ENGN,S-41296 GOTHENBURG,SWEDEN. JAPAN ENERGY ARC CO LTD,TODA,SAITAMA 335,JAPAN. RP Penn, DR (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. RI Clark, Charles/A-8594-2009; Tanuma, Shigeo/H-2681-2011 OI Clark, Charles/0000-0001-8724-9885; NR 23 TC 10 Z9 10 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD SEP PY 1997 VL 69 IS 2 BP 69 EP 81 DI 10.1016/S0304-3991(97)00039-9 PG 13 WC Microscopy SC Microscopy GA XW974 UT WOS:A1997XW97400001 ER PT J AU Mead, CM AF Mead, CM TI The discrimination between tornadic and nontornadic supercell environments: A forecasting challenge in the southern United States SO WEATHER AND FORECASTING LA English DT Article ID SIMULATED CONVECTIVE STORMS; THUNDERSTORMS; MESOCYCLONES; PROPAGATION; ROTATION; SHEAR AB Recent results from storm-scale modeling experiments have suggested that the strength of the 3-7-km storm-relative wind plays a very important role in determining whether or not a storm that already exhibits midlevel updraft rotation will, in fact, develop a persistent low-level mesocyclone, a feature commonly observed prior to tornadogenesis. This concept and others are applied to a total of 73 southern U.S. proximity soundings that have been compiled over a 36-yr period, 1960-95, in an attempt to discriminate between tornadic and nontornadic supercell environments. Of the 73 proximity soundings, 45 were classified as southern plains tornadic and 28 were southern plains nontornadic. The results of this study suggest that strength of the 2-9-km storm-relative wind, when used in combination with some measure of thermodynamic instability, or even the energy-helicity index, has proven to be a good indicator of whether or not an environment is supportive of tornadic supercells. Also, the magnitude of the 0-6-km wind shear was observed to be significantly higher in the tornadic soundings in comparison to the nontornadic cases. C1 NOAA,NATL WEATHER SERV OFF,MIDLAND,TX. NR 29 TC 3 Z9 6 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 SEP PY 1997 VL 12 IS 3 BP 379 EP 387 DI 10.1175/1520-0434(1997)012<0379:TDBTAN>2.0.CO;2 PN 1 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400002 ER PT J AU Wicker, LJ Kay, MP Foster, MP AF Wicker, LJ Kay, MP Foster, MP TI STORMTIPE-95: Results from a convective storm forecast experiment SO WEATHER AND FORECASTING LA English DT Article AB During the spring of 1995, an operational forecast experiment using a three-dimensional cloud model was carried out for the north Texas region. Gridpoint soundings were obtained from the daily operational numerical weather prediction models run at the National Centers for Environmental Prediction, and these soundings were then used to initialize a limited-domain cloud-resolving model in an attempt to predict convective storm type and morphology in a timely manner. The results indicate that this type of convective forecast may be useful in the operational environment, despite several limitations associated with this methodology. One interesting result from the experiment is that while the gridpoint soundings obtained from the NCEP models generally overforecast instability and vertical wind shear, the resulting convective storm evolution and morphology in the cloud model was often similar to that of the observed storms. Therefore the ''overforecast'' of mesoscale environment's instability and vertical wind shear still resulted in a thunderstorm-scale forecast that provided useful information to operational forecasters. C1 NATL WEATHER SERV,FORECAST OFF,FT WORTH,TX. RP Wicker, LJ (reprint author), TEXAS A&M UNIV,DEPT METEOROL,COLLEGE STN,TX 77843, USA. NR 11 TC 13 Z9 14 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 SEP PY 1997 VL 12 IS 3 BP 388 EP 398 DI 10.1175/1520-0434(1997)012<0388:SRFACS>2.0.CO;2 PN 1 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400003 ER PT J AU Hagemeyer, BC AF Hagemeyer, BC TI Peninsular Florida tornado outbreaks SO WEATHER AND FORECASTING LA English DT Article ID ENVIRONMENTS; CLIMATOLOGY; GENESIS; MARCH AB An analysis of statistics for 1448 tornadoes documented by the National Severe Storms Forecast Center from 1950 through 1994 at, or south of, 30 degrees latitude in Florida was completed to determine the definition of a peninsular Florida tornado outbreak and develop a tornado outbreak climatology. A peninsular Florida tornado outbreak was defined as the occurrence of four or more tornadoes in 4 h or less. Thirty-five outbreak cases were identified. After a review of all available synoptic data far each case, they were categorized into three basic types: 1) those associated with extratropical cyclones (27 cases), 2) those associated with tropical cyclones of tropical storm or hurricane strength (5 cases), and 3) those associated with hybrid cyclones having both tropical and extratropical characteristics (3 cases). A detailed climatology covering spatial and temporal aspects of outbreak characteristics was completed. Mean severe weather indices, thermodynamic soundings, and hodographs were produced for each outbreak type. Case studies of each type of outbreak are presented to complement the climatology and mean environment information. It was found that tornado outbreaks account for 3.4% of all tornado days but caused 61% of all tornado deaths and 62% of tornado injuries. Most tornado deaths occurred in trailers or mobile homes. Extratropical outbreak tornadoes were most common from midmorning to early afternoon, while tropical outbreak tornadoes occurred mostly in the afternoon and evening. The outbreaks produced a much greater percentage of strong and Violent tornadoes compared to the general tornado population. Hybrid outbreaks were the most consistently dangerous of the three types of outbreaks. Fundamental differences and similarities among the three outbreak environments are presented using mean soundings and case studies. The basic ingredients for tornado development in each type of outbreak were found to be the presence of strong low-level winds and shear, and enough instability to support thunderstorm development. RP Hagemeyer, BC (reprint author), NOAA,NATL WEATHER SERV,421 CROTON RD,MELBOURNE,FL 32935, USA. NR 54 TC 16 Z9 16 U1 1 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 SEP PY 1997 VL 12 IS 3 BP 399 EP 427 DI 10.1175/1520-0434(1997)012<0399:PFTO>2.0.CO;2 PN 1 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400004 ER PT J AU Hodanish, S Sharp, D Collins, W Paxton, C Orville, RE AF Hodanish, S Sharp, D Collins, W Paxton, C Orville, RE TI A 10-yr monthly lightning climatology of Florida: 1986-95 SO WEATHER AND FORECASTING LA English DT Article ID 1996 SUMMER OLYMPICS; NUMERICAL-MODEL; SOUTH FLORIDA; UNITED-STATES; CUMULONIMBUS; HURRICANES; MESOSCALE AB Average cloud-to-ground lightning flash density values for Florida have been calculated for the 10-yr period 1986-95. An annual mean map and monthly mean maps were constructed from a database exceeding 25 million hashes. These maps represent a 10-yr climatology of the geographic distribution of detected cloud-to-ground lightning flashes and provide an insight into the thunderstorm distribution in Florida. The locations of relative areas of lightning maxima and minima are strongly affected by the various combinations of synoptic and mesoscale contributions and are discussed. During the cool season, November-February, the greatest flash densities occur over the panhandle from storms mostly associated with midlatitude synoptic-scale systems. During the spring transitional period of March-May, hash densities increase over the entire state as synoptic contributions transition to mesoscale. Flash density totals in the warm season, June-August, exceed 10 flashes km(-2) in the central part of Florida. Flash density maxima in the summer are locally enhanced by mesoscale convergence and convection, especially along the west and east coasts of the central peninsula. Neither the panhandle nor the south peninsula show these impressive maxima. During the autumn transition period, September and October, flash densities decrease sharply across the state except for an area maximum that does remain over the eastern part of the peninsula. C1 TEXAS A&M UNIV,CIAMS,DEPT METEOROL,COLLEGE STN,TX 77843. NATL WEATHER SERV,MELBOURNE,FL. NATL WEATHER SERV,TAMPA,FL. RI Orville, Richard/G-9866-2012 OI Orville, Richard/0000-0003-0280-7169 NR 32 TC 37 Z9 40 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD SEP PY 1997 VL 12 IS 3 BP 439 EP 448 DI 10.1175/1520-0434(1997)012<0439:AYMLCO>2.0.CO;2 PN 1 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400006 ER PT J AU Glitto, P Choy, LB AF Glitto, P Choy, LB TI A comparison of WSR-88D storm total precipitation performance during two tropical systems following changes to the multiplicative bias and upper reflectivity threshold SO WEATHER AND FORECASTING LA English DT Article AB Seventy-two hours of Melbourne, Florida (KMLB), Weather Surveillance Radar 1988 Doppler (WSR-88D) rainfall data were compared with rain gauge data during Tropical Storm Gordon as it impacted east-central Florida. Comparisons were made by centering arrays of 9 and 25 storm total precipitation (STP) data bins over corresponding rain gauge locations, then performing bias and dispersion calculations prescribed by the Operational Support Facility (OSF). Findings indicate that the STP significantly underestimated rainfall during Tropical Storm Gordon and the magnitude of error varied with range from the radar. Based on these findings, it was recommended that the upper reflectivity threshold be increased to 55 dBZ and the multiplicative bias be set to 1.4 as an immediate but interim measure to minimize the differences between the STP and surface rain gauges during tropical systems. These recommended changes were given approval by the OSF and were deployed on the KMLB WSR-88D for a 72-h period as Tropical Storm Jerry affected east-central Florida. Significant improvement was noted in the STP product during Tropical Storm Jerry. Future studies will utilize base data replay capabilities to manipulate algorithms, biases, and thresholds individually and collectively to develop better radar rainfall adjustment schemes. Future work will also involve deploying tropical rainfall Z-R relationships that should further improve on the WSR-88D's rainfall estimation capability during tropical systems. C1 NATL OPERAT HYDROL REMOTE SENSING CTR,AIRBORNE SNOW SURVEY PROGRAM,CHANHASSEN,MN. RP Glitto, P (reprint author), NATL WEATHER SERV,421 CROTON RD,MELBOURNE,FL 32935, USA. NR 12 TC 8 Z9 8 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD SEP PY 1997 VL 12 IS 3 BP 459 EP 471 DI 10.1175/1520-0434(1997)012<0459:ACOWST>2.0.CO;2 PN 1 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400008 ER PT J AU Amburn, SA Wolf, PL AF Amburn, SA Wolf, PL TI VIL density as a hail indicator SO WEATHER AND FORECASTING LA English DT Article AB In current severe thunderstorm warning operations, forecasters frequently use the vertically integrated liquid water content (Vn) product from the WSR-88D to estimate thunderstorm severity and, particularly, hail size. Since VIL varies greatly based on airmass characteristics, forecasters have typically determined a threshold VIL to be used for each new thunderstorm event. A product that is independent of airmass characteristics, and thus independent of season and geographic location, would be more desirable in an operational warning environment. It has been observed that high-topped thunderstorms with high VILs do not alway produce large hail. It has also been observed that low-topped thunderstorms with low VILs occasionally do produce large hail. However, the maximum reflectivity in both high-topped and low-topped thunderstorms is similar when both produce similar-sized hail. From this, it was hypothesized that dividing the VV, by the echo tap would ''normalize'' the VIL and produce a common value, or range of values, for thunderstorms producing large hail, independent of airmass characteristics. This quotient is defined as VIL density in this study. To test the hypothesis, thunderstorm VIL and echo tops were recorded over a wide range of airmass characteristics, and VIL density was calculated. The data were correlated to surface-based reports of hail. The results showed a substantial increase in severe hail (greater than or equal to 19 mm, 3/4 in.) reports as VIL density increased above 3.5 gm(-3) At values greater than 4.0 gm(-3), virtually every thunderstorm produced severe-criteria hail, regardless of the actual VIL or the thunderstorm height. At values below 3.5 gm(-3), very few thunderstorms produced severe-criteria hail. RP Amburn, SA (reprint author), NATL WEATHER SERV,10159 E 11TH ST,SUITE 300,TULSA,OK 74128, USA. NR 5 TC 52 Z9 76 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD SEP PY 1997 VL 12 IS 3 BP 473 EP 478 DI 10.1175/1520-0434(1997)012<0473:VDAAHI>2.0.CO;2 PN 1 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400009 ER PT J AU Spratt, SM Sharp, DW Welsh, P Sandrik, A Alsheimer, F Paxton, C AF Spratt, SM Sharp, DW Welsh, P Sandrik, A Alsheimer, F Paxton, C TI A WSR-88D assessment of tropical cyclone outer rainband tornadoes SO WEATHER AND FORECASTING LA English DT Article ID HURRICANE-ANDREW; ENVIRONMENTS; SIMULATIONS AB As part of the National Weather Service (NWS) Modernization and Restructuring Program, WSR-88D (NEXRAD) Doppler radar installation has been completed at each Weather Service Office in Florida. Recently, this powerful new tool provided unique opportunities for Jacksonville, Tampa Bay, and Melbourne NEXRAD Weather Service Office personnel to investigate tropical cyclone (TC) rainbands for evidence of tornadogenesis. This study provides a radar-based analysis of known tornadic mesocyclones associated with two mature tropical cyclones that were not landfalling in the vicinity of the tornado occurrence, namely, Tropical Storm Gordon (1994) and Hurricane Allison (1995). Based on successful NEXRAD sampling strategies, detailed analyses of storm-scale reflectivity and velocity signatures are conducted in the context of establishing preliminary critical criteria for use in the tornado detection and warning process. Important characteristics were found to include detection of discrete, small diameter >50 dBZ echos collocated with storm-relative rotational velocities of 6.5-15 ms(-1). Rotational features, although often subtle, were identifiable for an average of 30 min prior to tornado production, with total durations of 1-2 h. Near the time of tornado touchdown, the core diameter of the low-level circulation couplets contracted to approximately 1.85 km (1 n mi), leading to an associated increase of shear across the circulation to 0.010 s(-1) or greater. A comparison between the well-studied Great Plains tornadic supercell and the observed TC-tornado cells revealed a common trait of persistence. While the average depth of rotation associated with the TC-tornado cells (3.5 km) was much more shallow than their midwest counterparts, the ratio of depth of rotation to storm top were comparable. However, the shallow depth-and weaker detectable rotation of the TC (tornadic) mesocyclones greatly reduced the detection capability of the current WSR-88D mesocyclone algorithm when compared to identification of traditional supercells. Based upon the analyzed data, the authors offer several recommendations to assist operational radar meteorologists with the challenging task of detecting outer rainband tornadoes. Additionally, the authors propose a new WSR-88D scan strategy (volume coverage pattern, VCP) that would provide additional low-level slices in lieu of several current upper-elevation angles. This new VCP would facilitate improved vertical sampling at lower heights where TC mesoscale circulations are most likely to be detected. C1 NATL WEATHER SERV,WEATHER SERV OFF,NEXRAD,JACKSONVILLE,FL. NATL WEATHER SERV,NEXRAD,WEATHER SERV OFF,TAMPA,FL. RP Spratt, SM (reprint author), NATL WEATHER SERV,WEATHER SERV OFF,NEXRAD,421 CROTON RD,MELBOURNE,FL 32935, USA. NR 40 TC 37 Z9 41 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD SEP PY 1997 VL 12 IS 3 BP 479 EP 501 DI 10.1175/1520-0434(1997)012<0479:AWAOTC>2.0.CO;2 PN 1 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400010 ER PT J AU Croft, PJ Pfost, RL Medlin, JM Johnson, GA AF Croft, PJ Pfost, RL Medlin, JM Johnson, GA TI Fog forecasting for the southern region: A conceptual model approach SO WEATHER AND FORECASTING LA English DT Article ID RADIATION FOG; MICROPHYSICS AB The prediction of fog occurrence, extent, duration, and intensity remains difficult despite improvements in numerical guidance and modeling of the fog phenomenon. This is because of the dependency of fog on microphysical and mesoscale processes that act within the boundary layer and that, in turn, are forced by the prevailing synoptic regime. Given existing and new technologies and techniques already available to the operational forecaster, fog prediction may be improved by the development and application of a simple conceptual model. A preliminary attempt at such a model is presented for the southern region of the United States (gulf coastal states) and requires information regarding cloud condensation nuclei, moisture availability (or saturation), and dynamic forcing. Each of these factors are assessed with regard to their extent and evolution with time. An illustration, and potential application, of how the model could be used is detailed as no extensive operational testing has yet been completed. Instead, the model is applied in hindcast to verify its application. Successful use of the model will require an operational forecaster to assimilate all available tools including climatology, numerical guidance, sounding analysis, model diagnostic software, and satellite imagery. These must be used to characterize and quantify the nature of the local and regional boundary layer in the forecast region according to macroscale forcing and moisture availability, the initial local settings and boundary layer, qualitative assessment of cloud condensation nuclei, and the interaction of these in time and space. Once identified, the evolution of the boundary layer may be forecast with regard to the overall environment for fog occurrence, its likely extent, intensity, and duration. C1 NATL WEATHER SERV,JACKSON,MS. NATL WEATHER SERV,MOBILE,AL. NATL WEATHER SERV,SLIDELL,LA. RP Croft, PJ (reprint author), JACKSON STATE UNIV,DEPT PHYS & ATMOSPHER SCI,1400 JR LYNCH ST,POB 17660,JACKSON,MS 39217, USA. NR 34 TC 27 Z9 29 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD SEP PY 1997 VL 12 IS 3 BP 545 EP 556 DI 10.1175/1520-0434(1997)012<0545:FFFTSR>2.0.CO;2 PN 1 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400014 ER PT J AU Pfost, RL Gerard, AE AF Pfost, RL Gerard, AE TI ''Bookend vortex'' induced tornadoes along the Natchez Trace SO WEATHER AND FORECASTING LA English DT Article ID BOW ECHO AB This study focuses on the evolution of the northern end of a bow echo that moved across parts of southwest Mississippi on 8 May 1995. A well-defined, cyclonically rotating ''comma head echo'' developed north of Natchez, Mississippi, and moved northeast for about 120 km (75 mi) before dissipating. The circulation associated with this comma head echo passed through several diameter changes during which the diameter varied between that of a classic mesocyclone and that more typical of a ''bookend vortex.'' The circulation and a strong rear inflow jet helped spawn small tornadoes (F0-F2) in Claiborne County, Mississippi, and wind damage in western Hinds County, Mississippi. The observed damage path from the tornadoes was more than 8 km (5 mi) long. For much of the track, the tornadoes paralleled the Natchez Trace, a scenic federal highway that extends from Natchez to Nashville, Tennessee. RP Pfost, RL (reprint author), NATL WEATHER SERV,FORECAST OFF,234 WEATHER SERV DR,JACKSON,MS 39208, USA. NR 12 TC 13 Z9 13 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 SEP PY 1997 VL 12 IS 3 BP 572 EP 580 DI 10.1175/1520-0434(1997)012<0572:BVITAT>2.0.CO;2 PN 1 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX404 UT WOS:A1997XX40400016 ER PT J AU Caplan, P Derber, J Gemmill, W Hong, SY Pan, HL Parrish, D AF Caplan, P Derber, J Gemmill, W Hong, SY Pan, HL Parrish, D TI Changes to the 1995 NCEP operational medium-range forecast model analysis-forecast system SO WEATHER AND FORECASTING LA English DT Article ID BOUNDARY-LAYER; OBSERVING SYSTEM; DIFFUSION; INTERPOLATION AB Recent changes in the operational National Centers for Environmental Prediction (formerly the National Meteorological Center) global analysis-forecast system are described. The most significant analysis change was the direct use of satellite-measured radiances as input to the analysis system. Other analysis system changes involved the inclusion of near-surface winds from the ERS-1 satellite system and the addition of a constraint on the divergence increment. In the forecast model, the parameterization of deep convection and the boundary layer scheme were modified. During two months of tests (June and July 1995), the new system produced substantially better forecasts of geopotential height and wind throughout the troposphere, especially in the Southern Hemisphere. Precipitation forecasts over the United States were slightly more skillful in the new system. Subjective evaluations over the Tropics revealed that the new model is more active at smalt scales, producing more clearly defined convective rain cores and vorticity patterns. RP NATL CTR ENVIRONM PREDICT, ENVIRONM MODELING CTR, W NP2, 4700 SILVER HILL RD, STOP 9910, WASHINGTON, DC 20233 USA. RI Hong, Song-You/I-3824-2012 NR 27 TC 98 Z9 99 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 EI 1520-0434 J9 WEATHER FORECAST JI Weather Forecast. PD SEP PY 1997 VL 12 IS 3 BP 581 EP 594 DI 10.1175/1520-0434(1997)012<0581:CTTNOM>2.0.CO;2 PN 2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX405 UT WOS:A1997XX40500001 ER PT J AU Stensrud, DJ Cortinas, JV Brooks, HE AF Stensrud, DJ Cortinas, JV Brooks, HE TI Discriminating between tornadic and nontornadic thunderstorms using mesoscale model output SO WEATHER AND FORECASTING LA English DT Article ID SIMULATED CONVECTIVE STORMS; NUMERICAL-SIMULATION; PARAMETERIZATION; ENVIRONMENTS; SYSTEMS; PRECIPITATION; MESOCYCLONES; VERIFICATION; PREDICTION; RESOLUTION AB The ability to discriminate between tornadic and nontornadic thunderstorms is investigated using a mesoscale model. Nine severe weather events are simulated: four events are tornadic supercell thunderstorm outbreaks that occur in conjunction with strong large-scale forcing for upward motion, three events are bow-echo outbreaks that also occur in conjunction with strong large-scale forcing for upward motion, and two are isolated tornadic supercell thunderstorms that occur under much weaker large-scale forcing. Examination of the mesoscale model simulations suggests that it is possible to discriminate between tornadic and nontornadic thunderstorms by using the locations of model-produced convective activity and values of convective available potential energy to highlight regions of likely thunderstorm development, and then using the values of storm-relative environmental helicity (SREH) and bulk Richardson number shear (BRNSHR) to indicate whether or not tornadic supercell thunderstorms are likely. Values of SREH greater than 100 m(2) s(-2) indicate a likelihood that any storms that develop will have a midlevel mesocyclone, values of BRNSHR between 40 and 100 m(2) s(-2) suggest that low-level mesocyclogenesis is likely, and values of BRNSHR less than 40 m(2) s(-2) suggest that the thunderstorms will be dominated by outflow. By combining the storm characteristics suggested by these parameters, it is possible to use mesoscale model output to infer the dominant mode of severe convection. C1 COOPERAT INST MESOSCALE METEOROL STUDIES, NORMAN, OK USA. RP NOAA, ENVIRONM RES LAB, NATL SEVERE STORMS LAB, 1313 HALLEY CIRCLE, NORMAN, OK 73069 USA. NR 48 TC 43 Z9 48 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 EI 1520-0434 J9 WEATHER FORECAST JI Weather Forecast. PD SEP PY 1997 VL 12 IS 3 BP 613 EP 632 DI 10.1175/1520-0434(1997)012<0613:DBTANT>2.0.CO;2 PN 2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX405 UT WOS:A1997XX40500003 ER PT J AU Knaff, JA Landsea, CW AF Knaff, JA Landsea, CW TI An El Nino Southern Oscillation climatology and persistence (CLIPER) forecasting scheme SO WEATHER AND FORECASTING LA English DT Article ID SEA-SURFACE TEMPERATURE; TROPICAL CYCLONE MOTION; OCEAN-ATMOSPHERE MODEL; EQUATORIAL PACIFIC; PREDICTION; ENSO; PREDICTABILITY; VARIABILITY; ATLANTIC; SYSTEM AB A statistical prediction method, which is based entirely on the optimal combination of persistence, month-to-month trend of initial conditions, and climatology, is developed for the El Nino-Southern Oscillation (ENSO) phenomena. The selection of predictors is by design intended to avoid any pretense of predictive ability based on ''model physics'' and the like, but rather is to specify the optimal ''no-skill'' forecast as a baseline comparison for more sophisticated forecast methods. Multiple least squares regression using the method of leaps and bounds is employed to test a total of 14 possible predictors for the selection of the best predictors, based upon 1950-94 developmental data. A range of zero to four predictors were chosen in developing 12 separate regression models, developed separately for each initial calendar month. The predictands to be forecast include the Southern Oscillation (pressure) index (SOI) and the Nino 1+2, Nino 3, Nino 4, and Nino 3.4 SST indices for the equatorial eastern and central Pacific at lead times ranging from zero seasons (0-2 months) through seven seasons (21-23 months). Though hindcast ability is strongly seasonally dependent, substantial improvement is achieved over simple persistence wherein largest gains occur for two-seven-season (6-23 months) lead times. For example, expected maximum forecast ability for the Nino 3.4 SST region, depending on the initial date, reaches 92%, 85%, 64%, 41%, 36%, 24%, 24%, and 28% of variance for leads of zero to seven seasons. Comparable maxima of persistence only forecasts explain 92%, 77%, 50%, 17%, 6%, 14%, 21%, and 17%, respectively. More sophisticated statistical and dynamic forecasting models are encouraged to utilize this ENSO-CLIPER model in place of persistence when assessing whether they have achieved forecasting skill; to this end, real-time results for this model are mode available via a Web site. C1 NOAA,HURRICANE RES DIV,MIAMI,FL. RP Knaff, JA (reprint author), COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523, USA. RI Knaff, John /F-5599-2010 OI Knaff, John /0000-0003-0427-1409 NR 45 TC 33 Z9 34 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD SEP PY 1997 VL 12 IS 3 BP 633 EP 652 DI 10.1175/1520-0434(1997)012<0633:AENOSO>2.0.CO;2 PN 2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX405 UT WOS:A1997XX40500004 ER PT J AU Pu, ZX Kalnay, E Parrish, D Wu, WS Toth, Z AF Pu, ZX Kalnay, E Parrish, D Wu, WS Toth, Z TI The use of bred vectors in the NCEP global 3D variational analysis system SO WEATHER AND FORECASTING LA English DT Article ID NUMERICAL WEATHER PREDICTION AB The errors in the first-guess (forecast field) of an analysis system vary from day to day, but, as in all current operational data assimilation systems, forecast error covariances are assumed to be constant in time in the NCEP operational three-dimensional variational analysis system (known as a spectral statistical interpolation or SSI). This study focuses on the impact of modifying the error statistics by including effects of the ''errors of the day'' on the analysis system. An estimate of forecast uncertainty, as defined from the bred growing vectors of the NCEP operational global ensemble forecast, is applied in the NCEP operational SSI analysis system. The growing vectors are used to estimate the spatially and temporally varying degree of uncertainty in the first-guess forecasts used in the analysis. The measure of uncertainty is defined by a ratio of the local amplitude of the growing vectors, relative to a background amplitude measure over a large area. This ratio is used in the SSI system for adjusting the observational error term (giving more weight to observations in regions of larger forecast errors). Preliminary experiments with the low-resolution global system show positive impact of this virtually cost-free method on the quality of the analysis and medium-range weather forecasts, encouraging further tests for operational use. The results of a 45-day parallel run, and a discussion of other methods to take advantage of the knowledge of the day-to-day variation in forecast uncertainties provided by the NCEP ensemble forecast system, are also presented in the paper. C1 NOAA,NATL WEATHER SERV,NATL CTR ENVIRONM PREDICT,ENVIRONM MODELING CTR,WASHINGTON,DC 20233. 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 15 TC 10 Z9 10 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 SEP PY 1997 VL 12 IS 3 BP 689 EP 695 DI 10.1175/1520-0434(1997)012<0689:TUOBVI>2.0.CO;2 PN 2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX405 UT WOS:A1997XX40500008 ER PT J AU Zhao, QY Black, TL Baldwin, ME AF Zhao, QY Black, TL Baldwin, ME TI Implementation of the cloud prediction scheme in the Eta Model at NCEP SO WEATHER AND FORECASTING LA English DT Article ID STEP-MOUNTAIN COORDINATE; MESOSCALE; PARAMETERIZATION AB An explicit cloud prediction scheme has been developed and incorporated into the Eta Model at the National Centers for Environmental Prediction (NCEP) to improve the cloud and precipitation forecasts. In this scheme, the cloud liquid water and cloud ice are explicitly predicted by adding only one prognostic equation of cloud mixing ratio to the model. Precipitation of rain and snow in this scheme is diagnostically calculated from the predicted cloud fields. The model-predicted clouds are also used in the model's radiation calculations. Results from the parallel tests performed at NCEP show improvements in precipitation forecasts when prognostic cloud water is included. Compared with the diagnostic clouds, the model-predicted clouds are more accurate in both amount and position. Improvements in specific humidity forecasts have also been found, especially near the surface and above the freezing level. C1 NOAA,NWS,NATL CTR ENVIRONM PREDICT,GEN SCI CORP,CAMP SPRINGS,MD 20746. NOAA,NATL WEATHER SERV,NATL CTR ENVIRONM PREDICT,WASHINGTON,DC 20233. NR 25 TC 53 Z9 53 U1 1 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 SEP PY 1997 VL 12 IS 3 BP 697 EP 712 DI 10.1175/1520-0434(1997)012<0697:IOTCPS>2.0.CO;2 PN 2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX405 UT WOS:A1997XX40500009 ER PT J AU Holden, M Mayhew, M Bunk, D Roitberg, A Vilker, V AF Holden, M Mayhew, M Bunk, D Roitberg, A Vilker, V TI Probing the interactions of putidaredoxin with redox partners in camphor p450 5-monooxygenase by mutagenesis of surface residues SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID PSEUDOMONAS-PUTIDA CYTOCHROME-P-450; ELECTRON-TRANSFER; REDUCED PUTIDAREDOXIN; CRYSTAL-STRUCTURE; ESCHERICHIA-COLI; OXIDIZED PUTIDAREDOXIN; AFFECT BINDING; REDUCTASE; IDENTIFICATION; EXPRESSION AB The role of surface amino acid residues in the interaction of putidaredoxin (Pdx) with its redox partners in the cytochrome P450(cam) (CYP101) system was investigated by site-directed mutagenesis. The mutated Pdx genes were expressed in Escherichia coli, and the proteins were purified and studied in vitro. Activity of the complete reconstituted P450(cam) system was measured, and kinetic parameters were determined, Partial assays were also conducted to determine the effect of the mutations on interactions with each redox partner. Some mutations altered interactions of Pdx with one redox partner but not the other, Other mutations affected interactions with both redox partners, suggesting some overlap in the binding sites on Pdx for putidaredoxin reductase and CYP101. Cysteine 73 of Pdx was identified as important in the interaction of Pdx with putidaredoxin reductase, whereas aspartate 38 serves a critical role in the subunit binding and electron transfer to CYP101. C1 NIST,CHEM SCI & TECHNOL LAB,DIV ANALYT CHEM,GAITHERSBURG,MD 20899. RP Holden, M (reprint author), NIST,CHEM SCI & TECHNOL LAB,DIV BIOTECHNOL,GAITHERSBURG,MD 20899, USA. RI Roitberg, Adrian/A-2378-2009 NR 29 TC 69 Z9 69 U1 0 U2 3 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD AUG 29 PY 1997 VL 272 IS 35 BP 21720 EP 21725 DI 10.1074/jbc.272.35.21720 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XT850 UT WOS:A1997XT85000012 PM 9268300 ER PT J AU Ruvinov, S Wang, L Ruan, B Almog, O Gilliland, GL Eisenstein, E Bryan, PN AF Ruvinov, S Wang, L Ruan, B Almog, O Gilliland, GL Eisenstein, E Bryan, PN TI Engineering the independent folding of the subtilisin BPN' prodomain: Analysis of two-state folding versus protein stability SO BIOCHEMISTRY LA English DT Article ID HYDROPHOBIC INTERACTION; RIBONUCLEASE; DOMAINS; COMPLEX; B1; B2 AB In complex with subtilisin BPN', the 77 amino acid prodomain folds into a stable compact structure comprising a four-stranded antiparallel beta-sheet and two three-turn a-helices. When isolated from subtilisin, the prodomain is 97% unfolded even under optimal folding conditions, Traditionally, to study stable proteins, denaturing cosolvents or temperatures are used to shift the equilibrium from folded to unfolded. Here we manipulate the folding equilibrium of the unstable prodomain by introducing stabilizing mutations generated by design. By sequentially introducing three stabilizing mutations into the prodomain we are able to shift the equilibrium for independent folding from 97% unfolded to 65% folded. Spectroscopic and thermodynamic analysis of the folding reaction was carried out to assess the effect of stability on two-state behavior and the denatured state. The denatured states of single and combination mutants are not discernably different in spite of a range of Delta G(unfolding) from -2.1 to 0.4 kcal/mol. Conclusions about the nature of the denatured state of the prodomain are based on CD spectral data and calorimetric data. Two state folding is observed for a combination mutant of marginal stability (Delta G = 0). Evidence for its two-state folding is based on the observed additivity of individual mutations to the overall Delta G(unfolding) and the conformity of Delta G(unfolding) VS T to two-state assumptions as embodied in the Gibbs-Helmholz equation. We believe our success in stabilizing the two-state folding reaction of the prodomain originates from the selection of mutations with improved ability to fold subtilisin rather than selection for increase in secondary structure content. The fact that a small number of mutations can stabilize the independent folding of the prodomain implies that most of the folding information already exists in the wild-type amino acid sequence in spite of the fact that the unfolded state predominates. C1 UNIV MARYLAND,MARYLAND BIOTECHNOL INST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NATL INST STAND & TECHNOL,ROCKVILLE,MD 20850. FU NIGMS NIH HHS [GM42560] NR 34 TC 36 Z9 36 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD AUG 26 PY 1997 VL 36 IS 34 BP 10414 EP 10421 DI 10.1021/bi9703958 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XT761 UT WOS:A1997XT76100007 PM 9265621 ER PT J AU Li, HQ Ono, RH Vale, LR Rudman, DA Liou, SH AF Li, HQ Ono, RH Vale, LR Rudman, DA Liou, SH TI High temperature superconducting Josephson junctions in a stacked bicrystal geometry SO APPLIED PHYSICS LETTERS LA English DT Article ID TRANSPORT-PROPERTIES; GRAIN-BOUNDARIES AB Bicrystal grain boundary Josephson junctions were fabricated in a stack of two layers of YBa2Cu3Ox separated by epitaxial SrTiO3. Weak link behavior was observed in the bridges formed in both layers that had similar shunted-junction characteristics but significantly different critical currents. Characteristic voltages up to 1.9 mV were measured at 4.5 K. The resonant structure was seen in the current-voltage characteristics of the upper-layer junctions, and interactions between junctions in the two layers were evident. (C) 1997 American Institute of Physics. C1 UNIV NEBRASKA,LINCOLN,NE 68588. RP Li, HQ (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 25 PY 1997 VL 71 IS 8 BP 1121 EP 1123 DI 10.1063/1.119746 PG 3 WC Physics, Applied SC Physics GA XR754 UT WOS:A1997XR75400044 ER PT J AU Belyakov, MY Kiselev, SB Rainwater, JC AF Belyakov, MY Kiselev, SB Rainwater, JC TI Crossover Leung-Griffiths model and the phase behavior of dilute aqueous ionic solutions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NONASYMPTOTIC CRITICAL-BEHAVIOR; GLOBAL THERMODYNAMIC BEHAVIOR; LIQUID-VAPOR RELATIONS; CRITICAL REGION; FLUID MIXTURES; CRITICAL-POINT; CRITICAL EXPONENT; SYSTEM NACL-H2O; CORRESPONDING STATES; COEXISTENCE CURVE AB A new parametric crossover model for the phase behavior of a binary mixture is presented that corresponds to the Leung-Griffiths model in the critical region and is transformed into the regular classical expansion far away from the critical point. The model is optimized to, and leads to excellent agreement with, isothermal vapor-liquid equilibrium data for dilute aqueous solutions of sodium chloride by Bischoff and co-workers. It then accurately predicts constant-composition phase equilibrium loci as measured by independent workers. This crossover model is therefore capable of representing the thermodynamic surface of ionic solutions in a large range of temperatures and densities around the critical points of vapor-liquid equilibrium. C1 RUSSIAN ACAD SCI, INST OIL & GAS RES, MOSCOW 117917, RUSSIA. RP Belyakov, MY (reprint author), NATL INST STAND & TECHNOL, PHYS & CHEM PROPERTIES DIV, 325 BROADWAY, BOULDER, CO 80303 USA. NR 89 TC 42 Z9 42 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 22 PY 1997 VL 107 IS 8 BP 3085 EP 3097 DI 10.1063/1.474663 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XR572 UT WOS:A1997XR57200042 ER PT J AU Lavrentyev, PJ Gardner, WS Johnson, JR AF Lavrentyev, PJ Gardner, WS Johnson, JR TI Cascading trophic effects on aquatic nitrification: experimental evidence and potential implications SO AQUATIC MICROBIAL ECOLOGY LA English DT Review DE nitrification; protozoa; zooplankton; bacterivory; predation ID NW MEDITERRANEAN-SEA; MICROBIAL FOOD-WEB; FRESH-WATER; COMMUNITY STRUCTURE; HETEROTROPHIC BACTERIA; NITRIFYING BACTERIA; INORGANIC NITROGEN; PURPLE BACTERIA; LAKE-MICHIGAN; RIVER PLUME AB Experiments, using natural plankton collected from a eutrophic site in Saginaw Bay, Lake Huron (USA) and from a hypereutrophic wetland of southern Lake Erie (USA), were conducted to test the hypothesis that bacterivory can control aquatic nitrification rates. The dynamics of nitrogen and protists in these experiments revealed a consistent pattern: an increase in concentrations of nitrates due to oxidation of NH4+ always followed the collapse of bacterivorous nanoplankton populations. This collapse was, in turn, caused by predation pressure of larger ciliates and metazooplankton. Experiments, using enrichment batch cultures maintained at near-ambient concentrations of NH4+, indicated that bacterivorous protists can inhibit nitrification directly by reducing bacterial numbers and indirectly by promoting bacterial aggregation. The latter experiments also suggest that feeding strategies of microbial grazers, e.g. suspension-feeding Spumella sp, versus surface-feeding Bodo saltans, may determine their grazing impacts on nitrifiers. Finally, ingestion rates of fluorescently labeled nitrifying bacteria (FLNB) by the natural planktonic assemblage from Saginaw Bay demonstrated that nanoflagellates were able to efficiently prey on low concentrations of FLNB. Our study suggests that previously neglected trophic factors may be of potential importance for mediating nitrification rates in the pelagic environment. C1 UNIV MICHIGAN, COOPERAT INST LIMNOL & ECOSYST RES, ANN ARBOR, MI 48109 USA. NOAA, GREAT LAKES ENVIRONM RES LAB, ANN ARBOR, MI 48105 USA. NR 116 TC 31 Z9 32 U1 1 U2 10 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0948-3055 EI 1616-1564 J9 AQUAT MICROB ECOL JI Aquat. Microb. Ecol. PD AUG 21 PY 1997 VL 13 IS 2 BP 161 EP 175 DI 10.3354/ame013161 PG 15 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA XR814 UT WOS:A1997XR81400004 ER PT J AU Talukdar, RK Herndon, SC Burkholder, JB Roberts, JM Ravishankara, AR AF Talukdar, RK Herndon, SC Burkholder, JB Roberts, JM Ravishankara, AR TI Atmospheric fate of several alkyl nitrates .1. Rate coefficients of the reactions alkyl nitrates with isotopically labelled hydroxyl radicals SO JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS LA English DT Article ID GAS-PHASE REACTIONS; PEROXYACETYL NITRATE; OH RADICALS; CHEMISTRY; KINETICS; ALKANES; TROPOSPHERE; PHOTOLYSIS; MECHANISM; OZONE AB The rate coefficients for the reaction of OH radical with CH3ONO2 (k(1)), CD3ONO2 (k(6)), C2H5ONO, (k(2)) and 2-C3H7ONO2 (k(3)) between 220 and 410 K were measured to be: k(1) = (8.2 +/- 1.6) x 10(-13) exp{-(1020 +/- 60)/T}, k(6) = (1.6 +/- 0.2)(8.2 +/- 1.6) x 10(-13) exp{-(1020 +/- 60)/T}, k(6) = (1.6 +/- 0.2) x 10(-12) exp{-(1730 +/- 40)/T}, k(2)=3.68 x 10(-12) exp(-1077/T) + 5.32 x 10(-14) exp(126/T) and k(3)=4.3 x 10(-12) exp(-1250/T) + 2.5 x 10(-13) exp(-32/T) cm(3) molecule(-1)s(-1). The quoted errors in the Arrhenius expressions are at the 95% confidence limit and include estimated systematic errors. The measured rate coefficients for the reactions of (OH)-O-18 were roughly the same as those for (OH)-O-16 reactions while the rate constants for OD reactions were slightly (ca. 10-15%) higher than those for OH reactions. The hydroxyl radicals were generated by pulsed laser photolysis and detected by pulsed laser induced fluorescence. The observed large primary kinetic isotope effect(k(1)/k(6) = 4.5 at 298 K), the independence of the measured rate coefficients on the gas composition, and the trend in the reactivity with the alkyl group suggests that the above reactions proceed via abstraction of an H atom from the alkyl group. Our results are compared with those from previous studies. C1 NOAA,AERON LAB,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RI Roberts, James/A-1082-2009; TALUKDAR, RANAJIT/G-4530-2013; Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 OI Roberts, James/0000-0002-8485-8172; TALUKDAR, RANAJIT/0000-0001-6017-8431; NR 30 TC 49 Z9 49 U1 1 U2 13 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0956-5000 J9 J CHEM SOC FARADAY T JI J. Chem. Soc.-Faraday Trans. PD AUG 21 PY 1997 VL 93 IS 16 BP 2787 EP 2796 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XQ891 UT WOS:A1997XQ89100025 ER PT J AU Talukdar, RK Burkholder, JB Hunter, M Gilles, MK Roberts, JM Ravishankara, AR AF Talukdar, RK Burkholder, JB Hunter, M Gilles, MK Roberts, JM Ravishankara, AR TI Atmospheric fate of several alkyl nitrates .2. UV absorption cross-sections and photodissociation quantum yields SO JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS LA English DT Article ID ORGANIC NITRATES; METHYL NITRATE; NITRIC-ACID; 222 NM; TEMPERATURE; PHOTOLYSIS; RADICALS; NO3 AB The UV absorption cross-sections of methyl, ethyl and isopropyl nitrate between 233 and 340 nm have been measured using a diode array spectrometer in the temperature range 240-360 K. The absorption cross-sections of these alkyl nitrates decrease with increasing wavelength and decrease with decreasing temperature for lambda > 280 nm. The photodissociation quantum yield for CH3ONO2 to produce NO2 and CH3O was found to be essentially unity at 248 nm using transient UV absorption methods. Production of O and H atoms in the photodissociation of methyl nitrate at 248 and 308 mm were found to be negligible using resonance fluorescence detection of the atoms. High quantum yields for O atoms were measured following 193 nm photolysis of methyl nitrate. The OH radical was measured to be a photoproduct with a very small quantum yield. Using the OH rate coefficients reported in the accompanying paper and the UV absorption cross-sections and the photodissociation quantum yields measured here, the first-order rate constants for atmospheric loss of methyl, ethyl and isopropyl nitrate were calculated Photolysis was found to be the dominant atmospheric loss process for the three alkyl nitrates. C1 NOAA,AERON LAB,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RI Roberts, James/A-1082-2009; TALUKDAR, RANAJIT/G-4530-2013; Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 OI Roberts, James/0000-0002-8485-8172; TALUKDAR, RANAJIT/0000-0001-6017-8431; NR 33 TC 70 Z9 70 U1 0 U2 10 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0956-5000 J9 J CHEM SOC FARADAY T JI J. Chem. Soc.-Faraday Trans. PD AUG 21 PY 1997 VL 93 IS 16 BP 2797 EP 2805 DI 10.1039/a701781b PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XQ891 UT WOS:A1997XQ89100026 ER PT J AU Monroe, C AF Monroe, C TI Atomic physics - Shaping atoms in optical lattices SO NATURE LA English DT Editorial Material RP Monroe, C (reprint author), NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,325 BROADWAY,BOULDER,CO 80303, USA. RI Monroe, Christopher/G-8105-2011 NR 7 TC 2 Z9 2 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD AUG 21 PY 1997 VL 388 IS 6644 BP 719 EP 720 DI 10.1038/41885 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XR667 UT WOS:A1997XR66700025 ER PT J AU Palsboll, PJ Allen, J Berube, M Clapham, PJ Feddersen, TP Hammond, PS Hudson, RR Jorgensen, H Katona, S Larsen, AH Larsen, F Lien, J Mattila, DK Sigurjonsson, J Sears, R Smith, T Sponer, R Stevick, P Oien, N AF Palsboll, PJ Allen, J Berube, M Clapham, PJ Feddersen, TP Hammond, PS Hudson, RR Jorgensen, H Katona, S Larsen, AH Larsen, F Lien, J Mattila, DK Sigurjonsson, J Sears, R Smith, T Sponer, R Stevick, P Oien, N TI Genetic tagging of humpback whales SO NATURE LA English DT Article ID MEGAPTERA-NOVAEANGLIAE; SIMPLE SEQUENCES; DNA; POPULATION; MAINE; GULF AB The ability to recognize individual animals has substantially increased our knowledge of the biology and behaviour of many taxa(1). However, not all species lend themselves to this approach, either because of insufficient phenotypic variation or because tag attachment is not feasible. The use of genetic markers ('tags') represents a viable alternative to traditional methods of individual recognition, as they are permanent and exist in all individuals. We tested the use of genetic markers as the primary means of identifying individuals in a study of humpback whales in the North Atlantic Ocean. Analysis of six microsatellite loci(2,3) among 3,060 skin samples collected throughout this ocean allowed the unequivocal identification of individuals. Analysis of 692 'recaptures', identified by their genotype, revealed individual local and migratory movements of up to 10,000 km, limited exchange among summer feeding grounds, and mixing in winter breeding areas, and also allowed the first estimates of animal abundance based solely on genotypic data. Our study demonstrates that genetic tagging is not only feasible, but generates data (for example, on sex) that can be valuable when interpreting-the results of tagging experiments. C1 COLL ATLANTIC,BAR HARBOR,ME 04609. DEPT NAT RESOURCES SCI,ST ANNE BELLEVUE,PQ H9X 3V9,CANADA. CTR COASTAL STUDIES,PROVINCETOWN,MA 02657. UNIV ST ANDREWS,SEA MAMMAL RES UNIT,ST ANDREWS KY16 9LB,FIFE,SCOTLAND. UNIV CALIF IRVINE,DEPT ECOL & EVOLUTIONARY BIOL,IRVINE,CA 92697. GREENLAND INST NAT RESOURCES,NUUK 3900,GREENLAND. MEM UNIV NEWFOUNDLAND,WHALE RES GRP,ST JOHNS,NF A1B 3X9,CANADA. MARINE RES INST,IS-121 REYKJAVIK,ICELAND. MINGAN ISL CETACEAN STUDY INC,ST LAMBERT,PQ J4P 1T3,CANADA. NATL MARINE FISHERIES SERV,NE FISHERIES SCI CTR,WOODS HOLE,MA 02543. INST MARINE RES,N-5024 BERGEN,NORWAY. RP Palsboll, PJ (reprint author), DEPT POPULAT BIOL,UNIV PK 15,DK-2100 COPENHAGEN,DENMARK. RI Palsboll, Per /G-6988-2011 OI Palsboll, Per /0000-0002-4198-7599 NR 28 TC 154 Z9 165 U1 12 U2 62 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD AUG 21 PY 1997 VL 388 IS 6644 BP 767 EP 769 DI 10.1038/42005 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XR667 UT WOS:A1997XR66700049 PM 9285587 ER PT J AU Churnside, JH Wilson, JJ Tatarskii, VV AF Churnside, JH Wilson, JJ Tatarskii, VV TI Lidar profiles of fish schools SO APPLIED OPTICS LA English DT Article AB A lidar system was used in a seawater tank to measure the average diffuse reflectivity of live sardines. Diffuse reflectivity was measured to be 10% for a copolarized laser return and 3% for a cross-polarized return. We used these calibration measurements to infer the density of sardines in areas of the Southern California Eight from vertical profiles obtained with the lidar mounted on a ship. Within schools densities up to similar to 0.01 kg m(-3) were observed. During hourly survey periods total habitat densities up to similar to 2 X 10(-3) kg m(-2) were observed. (C) 1997 Optical Society of America. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. RP Churnside, JH (reprint author), NOAA,ENVIRONTECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Churnside, James/H-4873-2013 NR 8 TC 33 Z9 35 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 20 PY 1997 VL 36 IS 24 BP 6011 EP 6020 DI 10.1364/AO.36.006011 PG 10 WC Optics SC Optics GA XR271 UT WOS:A1997XR27100035 PM 18259445 ER PT J AU Machol, JL AF Machol, JL TI Comparison of the pseudorandom noise code and pulsed direct-detection lidars for atmospheric probing SO APPLIED OPTICS LA English DT Article DE lidar; pseudorandom noise code ID MODULATION CW LIDAR AB The advantages and limitations of using the pseudorandom-noise (PN)-code technique in comparison with pulsed direct detection are discussed. Because the signal-to-noise ratio (SNR) of the PN codes is dependent on the average atmospheric return, strong returns from short ranges and clouds determine the SNR for all ranges. The SNR of a profile obtained by pulsed direct detection exceeds that of the PN-code technique for laser beams with the same average power. (C) 1997 Optical Society of America. RP Machol, JL (reprint author), UNIV COLORADO,NOAA,ENVIRONM TECHNOL LAB,COOPERAT INST RES ENVIRONM SCI,325 BROADWAY,BOULDER,CO 80303, USA. RI Machol, Janet/D-5896-2016 OI Machol, Janet/0000-0002-0344-0314 NR 6 TC 11 Z9 12 U1 0 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 AUG 20 PY 1997 VL 36 IS 24 BP 6021 EP 6023 DI 10.1364/AO.36.006021 PG 3 WC Optics SC Optics GA XR271 UT WOS:A1997XR27100036 PM 18259446 ER PT J AU Rhoads, KP Kelley, P Dickerson, RR Carsey, TP Farmer, M Savoie, DL Prospero, JM AF Rhoads, KP Kelley, P Dickerson, RR Carsey, TP Farmer, M Savoie, DL Prospero, JM TI Composition of the troposphere over the Indian Ocean during the monsoonal transition SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; SIZE DISTRIBUTION; AMSTERDAM-ISLAND; CARBON-MONOXIDE; NITRIC-OXIDE; NITRATE; PACIFIC; AEROSOLS; SULFATE; NO AB The atmosphere over the equatorial Indian Ocean is a unique environment in which to study the chemical and radiative effects of an intense source of anthropogenic emissions from the northern hemisphere directly coupled to the relatively pristine background conditions present in the southern hemisphere. As an initial investigation into the role of the intertropical convergence zone (ITCZ) on interhemispheric transport of pollutants, a number of trace atmospheric species were measured aboard the National Oceanic and Atmospheric Administration (NOAA) R/V Malcolm Baldrige between Durban, South Africa, and Colombo, Sri Lanka, from March 12 to April 22, 1995. Sharp increases in the concentrations of carbon monoxide (CO), carbon dioxide (CO2), and aerosols were associated with four distinct meteorological regimes transected by the cruise track from 33 degrees S to 9 degrees N. Across the ITCZ, aerosol concentrations, including non-sea-salt sulfate, nitrate and ammonium, increased by a factor of 4. Surface ozone measurements showed a latitudinal gradient with a minimum near the equator and a strong diurnal variation in the equatorial regions. The latitudinal profile of gas-phase reactive nitrogen paralleled ozone and was higher in the remote southern hemisphere than in the remote northern hemisphere. Evidence of direct anthropogenic impact on the region was observed more than 1500 km from the southern tip of India. Back trajectories, calculated with NOAA's medium range forecast data using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HY-SPLIT) program, identified the origin of the air mass regimes characterized by the trace gas and aerosol data. Continental emissions in the northern hemisphere were shown to have a major impact on the radiative properties and oxidizing capacity of the marine atmosphere. C1 NOAA, ATLANTIC OCEANOG & METEOROL LAB, MIAMI, FL 33149 USA. UNIV MARYLAND, DEPT METEOROL, COLLEGE PK, MD 20742 USA. UNIV MIAMI, ROSENSTIEL SCH MARINE & ATMOSPHER SCI, MIAMI, FL 33149 USA. UNIV MARYLAND, CTR CLOUDS CHEM & CLIMATE, COLLEGE PK, MD 20742 USA. RP UNIV MARYLAND, DEPT CHEM, COLLEGE PK, MD 20742 USA. RI Carsey, Thomas/B-7939-2014; Dickerson, Russell/F-2857-2010; Kelley, Paul/C-9155-2016; OI Carsey, Thomas/0000-0001-9964-5092; Dickerson, Russell/0000-0003-0206-3083; Prospero, Joseph/0000-0003-3608-6160 NR 50 TC 81 Z9 84 U1 1 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 AUG 20 PY 1997 VL 102 IS D15 BP 18981 EP 18995 DI 10.1029/97JD01078 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XT101 UT WOS:A1997XT10100014 ER PT J AU HaasLaursen, DE Hartley, DE Conway, TJ AF HaasLaursen, DE Hartley, DE Conway, TJ TI Consistent sampling methods for comparing models to CO2 flask data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TRANSPORT MODEL AB We address the issue of how to compare atmospheric carbon dioxide (CO2) observations from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory (NOAA/CMDL) air sampling network to model output in a consistent method for model evaluation and inverse problems. Two steps are needed to ''sample'' the model using the same methodology that is applied to the flask samples: (1) ensure that the wind direction is one that is deemed acceptable in the field and (2) reject outliers. Since a ''clean air sector'' has only been determined for four sites, we compute a statistical analysis of the wind direction when samples are collected at 38 NOAA/CMDL CO2 collection sites operational from 1993-1995. We compare this to the wind directions from the European Centre for Medium-Range Weather Forecasts (ECMWF) assimilated wind fields for the same 3 year time period. From this analysis, we deduce which of the sites are selecting for wind direction. We then analyze model output to compare the effects on monthly mean concentration from this two-step methodology. We find that at the majority of sites the removal of outliers is particularly important. Finally, we explore the impact of sampling frequency in the model. At most sites, the sampling frequency does impact the model results. We conclude that it is best to use high-frequency model output rather than sampling with the same low-frequency as the flask network. The bias resulting from low-frequency sampling is potentially large, and if done in both the model and the observations, the comparison error is exacerbated. We estimate this bias error for use in error estimation and inverse problems. C1 NOAA, ENVIRONM RES LAB, BOULDER, CO 80303 USA. RP GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. NR 16 TC 9 Z9 9 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1997 VL 102 IS D15 BP 19059 EP 19071 DI 10.1029/97JD00795 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XT101 UT WOS:A1997XT10100020 ER PT J AU Gettelman, A Holton, JR Rosenlof, KH AF Gettelman, A Holton, JR Rosenlof, KH TI Mass fluxes of O-3, CH4, N2O and CF2Cl2 in the lower stratosphere calculated from observational data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DOWNWARD CONTROL; CIRCULATION; OZONE; TROPOSPHERE; ATMOSPHERE; BUDGET; SINKS AB Trace gas mixing ratio data from the Upper Atmosphere Research Satellite (UARS) are combined with a radiatively derived transformed Eulerian mean (TEM) stream function to estimate the net ozone (O-3) mass flux from the stratosphere to the troposphere and to investigate the net fluxes of methane (CH4), nitrous oxide (N2O), and CFC-12 (CF2Cl2) into the lower stratosphere. The mass fluxes of ozone and long-lived tracers such as nitrous oxide, methane, and CFC-12 in the lower stratosphere can be estimated from data obtained by the cryogenic limb array etalon spectrometer (CLAES), the microwave limb sounder (MLS) for ozone, and the Halogen Occultation Experiment (HALOE) for ozone and methane. The flux of ozone from the stratosphere to the troposphere is estimated to be 510 Tg of ozone per year with a range of 450 to 590 Tg O-3/yr. Net fluxes into the stratosphere are estimated as 27 Tg of methane per year, 8 Tg/yr of N in nitrous oxide, and 0.08 Tg/yr of CF2Cl2. There is good agreement with previous estimates within the range of uncertainty of these calculations. C1 NOAA, AERON LAB, BOULDER, CO 80303 USA. UNIV COLORADO, NOAA, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP UNIV WASHINGTON, BOX 351640, SEATTLE, WA 98195 USA. RI Rosenlof, Karen/B-5652-2008 OI Rosenlof, Karen/0000-0002-0903-8270 NR 43 TC 58 Z9 59 U1 0 U2 7 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 AUG 20 PY 1997 VL 102 IS D15 BP 19149 EP 19159 DI 10.1029/97JD01014 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XT101 UT WOS:A1997XT10100027 ER PT J AU Miller, AJ Flynn, LE Hollandsworth, SM DeLuisi, JJ Petropavlovskikh, IV Tiao, GC Reinsel, GC Wuebbles, DJ Kerr, J Nagatani, RM Bishop, L Jackman, CH AF Miller, AJ Flynn, LE Hollandsworth, SM DeLuisi, JJ Petropavlovskikh, IV Tiao, GC Reinsel, GC Wuebbles, DJ Kerr, J Nagatani, RM Bishop, L Jackman, CH TI Information content of Umkehr and solar backscattered ultraviolet (SBUV) 2 satellite data for ozone trends and solar responses in the stratosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NIMBUS-7; DEPLETION; LATITUDE AB Within the past few years, several papers have been published which present updated profile ozone trends from the recently revised ground-based Umkehr record [Miller et al., 1995] and the combined Nimbus 7 solar backscattered ultraviolet (SBUV) and NOAA 11 SBUV 2 satellite data record [Hollandsworth et al., 1995; Miller et al., 1996]. Within these papers, however, there has remained an overriding question as to the actual information content of the measurement systems and their ability to detect atmospheric responses. In this paper, we compare the ozone trends and responses to the 11-year solar cycle (derived from model and/or data specifications of these effects) to results of forward model/retrieval algorithm computations through the algorithms. We consider data at northern midlatitudes (30 degrees-50 degrees N) so that we may compare the satellite results with those of the ground-based systems. Our results indicate that the Umkehr data contain only four independent pieces of information in the vertical and that the SBUV system contains five. In particular, we find that consideration should be restricted to the following regions; Umkehr: the sum of Umkehr layers 1-5, and layers 6, 7, and 8+ (the sum of layers 8 and above), SBUV: the sum of layers 1-5, and layers 6, 7, 8, and 9+ (the sum of layers 9 and above). Additionally, we compare the actual trends and solar coefficients derived in these layers for the periods 1968-1991 and 1979-1991 for the Umkehr and SBUV data. Finally, we include within the latter comparisons the stratospheric aerosol and gas experiment (SAGE) I and II results from Wang et al. [1996] and the computations from the ozonesondes. C1 SOFTWARE CORP AMER, LANHAM, MD USA. APPL RES CORP, LANDOVER, MD 20785 USA. NOAA, AIR RESOURCES LAB, ENVIRONM RES LAB, BOULDER, CO 80303 USA. UNIV CHICAGO, GRAD SCH BUSINESS, CHICAGO, IL 60637 USA. UNIV WISCONSIN, DEPT STAT, MADISON, WI 53706 USA. UNIV ILLINOIS, DEPT ATMOSPHER SCI, URBANA, IL 61801 USA. ATMOSPHER ENVIRONM SERV, DOWNSVIEW, ON, CANADA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. ALLIED SIGNAL INC, BUFFALO, NY 14210 USA. NOAA, NATL ENVIRONM SATELLITE DATA & INFORMAT SERV, OFF RES & APPLICAT, WASHINGTON, DC 20233 USA. RP NOAA, NATL WEATHER SERV, CLIMATE PREDICT CTR, WASHINGTON, DC 20233 USA. RI Flynn, Lawrence/B-6321-2009; Jackman, Charles/D-4699-2012 OI Flynn, Lawrence/0000-0001-6856-2614; NR 23 TC 18 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1997 VL 102 IS D15 BP 19257 EP 19263 DI 10.1029/97JD01482 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XT101 UT WOS:A1997XT10100037 ER PT J AU Bodhaine, BA Dutton, EG Hofmann, DJ McKenzie, RL Johnston, PV AF Bodhaine, BA Dutton, EG Hofmann, DJ McKenzie, RL Johnston, PV TI UV measurements at Mauna Loa: July 1995 to July 1996 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SPECTRAL IRRADIANCE MEASUREMENTS; ULTRAVIOLET-RADIATION; OZONE AB A UV spectroradiometer was installed at Mauna Loa Observatory (MLO), Hawaii, in July 1995. This instrument, based on a commercially available double monochromator, uses a diffuser mounted as a horizontal receptor inside a quartz dome and views the whole sky. The instrument scans over the 290-450 mm spectral range with a band pass of about 1 mm for each 5 degrees of solar zenith angle (SZA). The UV irradiances measured at MLO are much more intense than at low-altitude midlatitude locations. For observations at SZA 45 degrees the erythemally weighted UV irradiances can exceed 21 mu W cm(-2), which is approximately 15-20% greater than that seen at Lauder, New Zealand, for similar ozone amounts. The difference is primarily due to the higher altitude at MLO (3.4 km). For overhead Sun conditions at MLO the largest value of erythemal UV was 51.3 +/- 3.1 mu W cm(-2), which to our knowledge is the highest recorded anywhere at the Earth's surface. UV irradiance is strongly correlated (inversely) with Dobson spectrophotometer total ozone measurements at MLO, with higher correlations at shorter wavelengths. The radiative amplification factor (RAF) for erythema at MLO is about 1.33 +/- 0.2 at SZA 45 degrees. C1 NATL INST WATER & ATMOSPHER RES LAUDER, CENTRAL OTAGO 9182, NEW ZEALAND. RP NOAA, CLIMATE MONITORING & DIAGNOST LAB, RECG1, 325 BROADWAY, BOULDER, CO 80303 USA. NR 25 TC 35 Z9 36 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1997 VL 102 IS D15 BP 19265 EP 19273 DI 10.1029/97JD01391 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XT101 UT WOS:A1997XT10100038 ER PT J AU Wenthold, PG Lineberger, WC AF Wenthold, PG Lineberger, WC TI Dehydrocyclooctatetraene. Photoelectron spectroscopy of the C8H6 anion SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID 8-MEMBERED RING COMPOUNDS; ELECTRON-AFFINITY; ATOMIC OXYGEN; CYCLOOCTATRIENYNE; PHOTODETACHMENT; MNDO AB The photoelectron spectrum of the dehydrocyclooctatetraene negative ion, C8H6-, is reported. The spectrum strongly resembles that previously reported for the cyclooctatetraene anion, indicating that the structure of C8H6- is very similar to that of C8H8-. Two electronic states of dehydrocyclooctatetraene are observed in the photoelectron spectrum. The lowest energy feature is assigned to singlet 1,3,5-cyclooctatrien-7-yne, while the higher energy band corresponds to a triplet state of dehydrocyclooctatetraene. The electron affinity of C8H6 is found to be 1.044 +/- 0.008 eV, and the energy difference between the singlet and triplet states is 0.708 +/- 0.006 eV. Vibrational activity is observed in the photoelectron spectrum and assigned using a simple potential energy surface. Stretching of the triple bond in cyclooctatrienyne is found to have a frequency of 2185 cm(-1), essentially what is expected for a triple bond within an eight-membered ring. Ab initio and density functional molecular orbital calculations on dehydrocyclooctatetraene and the corresponding ions are reported. Cyclooctatrienyne is calculated to have a planar or pseudoplanar structure, consistent with assignments based on peak widths in the photoelectron spectrum. 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 46 TC 15 Z9 15 U1 1 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 AUG 20 PY 1997 VL 119 IS 33 BP 7772 EP 7777 DI 10.1021/ja970934w PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA XT037 UT WOS:A1997XT03700019 ER PT J AU Kato, S Lee, HS Gareyev, R Wenthold, PG Lineberger, WC DePuy, CH Bierbaum, VM AF Kato, S Lee, HS Gareyev, R Wenthold, PG Lineberger, WC DePuy, CH Bierbaum, VM TI Experimental and computational studies of the structures and energetics of cyclooctatetraene and its derivatives SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GAS-PHASE; ANIONS; CHEMISTRY; ABINITIO C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,JILA,BOULDER,CO 80309. UNIV COLORADO,NATL INST STAND & TECHNOL,BOULDER,CO 80309. NR 25 TC 34 Z9 34 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD AUG 20 PY 1997 VL 119 IS 33 BP 7863 EP 7864 DI 10.1021/ja971433d PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA XT037 UT WOS:A1997XT03700029 ER PT J AU Fairey, ER Edmunds, JSG Ramsdell, JS AF Fairey, ER Edmunds, JSG Ramsdell, JS TI A cell-based assay for brevetoxins, saxitoxins, and ciguatoxins using a stably expressed c-fos-luciferase reporter gene SO ANALYTICAL BIOCHEMISTRY LA English DT Article ID SENSITIVE SODIUM-CHANNELS; DOMOIC ACID; SHELLFISH POISON; BIOASSAY C1 MED UNIV S CAROLINA,MARINE BIOMED & ENVIRONM SCI,CHARLESTON,SC 29412. RP Fairey, ER (reprint author), NOAA,SE FISHERIES SCI CTR,CHARLESTON LAB,MARINE BIOTOXINS PROGRAM,CHARLESTON,SC 29412, USA. NR 15 TC 28 Z9 33 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD AUG 15 PY 1997 VL 251 IS 1 BP 129 EP 132 DI 10.1006/abio.1997.2264 PG 4 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA XT972 UT WOS:A1997XT97200023 PM 9300098 ER PT J AU Borrmann, S Solomon, S Avallone, L Toohey, D Baumgardner, D AF Borrmann, S Solomon, S Avallone, L Toohey, D Baumgardner, D TI On the occurrence of ClO in cirrus clouds and volcanic aerosol in the tropopause region SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MIDLATITUDES; PINATUBO AB Airborne observations during descents of the ER-2 through layers of volcanic aerosol (Mount Pinatubo eruption of 1991) and a cirrus cloud are utilized to study the the abundance of ClO and its relation to aerosol surface area in the midlatitude tropopause region. During a cirrus event near the tropopause ClO mixing ratios up to 2.7 pptv were detected and near the tropopause ClO levels from a few to 70 pptv were found. These measurements are associated with large experimental uncertainties but demonstrate the possible presence of ClO inside cirrus clouds and near the tropopause. Model calculations show that possible enhancements of ClO by heterogeneous chemistry on cirrus cloud particles could considerably increase the ozone loss rates and could have implications for the ozone budget in this region. It is not possible to decide from the limited data base whether the observed ClO levels are due to transport or heterogeneous chemistry. C1 NOAA,AERON LAB,BOULDER,CO 80303. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,BOULDER,CO 80309. UNIV CALIF IRVINE,DEPT EARTH SYST SCI,IRVINE,CA 92717. RP Borrmann, S (reprint author), UNIV MAINZ,INST ATMOSPHER PHYS,BECHERWEG 21,D-55099 MAINZ,GERMANY. RI Borrmann, Stephan/E-3868-2010; Toohey, Darin/A-4267-2008 OI Toohey, Darin/0000-0003-2853-1068 NR 12 TC 25 Z9 26 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 AUG 15 PY 1997 VL 24 IS 16 BP 2011 EP 2014 DI 10.1029/97GL02053 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XR464 UT WOS:A1997XR46400012 ER PT J AU Sun, DZ AF Sun, DZ TI El Nino: A coupled response to radiative heating? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-SURFACE TEMPERATURE; SOUTHERN OSCILLATION; MODEL; ENSO AB The very existence of El Nino - the oscillatory behavior of the tropical Pacific climate - may be due to the warmth of the tropics (relative to the coldness of the high latitudes). This is elucidated by subjecting a mathematical model for the coupled tropical ocean-atmosphere system to a varying radiative heating. The temperature of the deep ocean is kept fixed. In response to an increasing radiative heating, the coupled system first experiences a pitch-fork bifurcation that breaks the zonal symmetry imposed by the solar radiation. The resulting zonal sea surface temperature (SST) gradients increase with increases in the radiative heating. When the zonal SST gradients exceed a critical value, a Hopf bifurcation takes place which brings the system to an oscillatory state, a state that closely resembles the observed tropical Pacific climate. Further increases in the radiative heating result in increases in the magnitude of the oscillation. The results shed new light on the physics of Fl Nino and suggest that climate change due to anthropogenic forcing may occur through the same dynamic modes that sustain natural variability. RP Sun, DZ (reprint author), NOAA,CIRES,CDC,CU,CLIMAT DIAGNOST CTR,CAMPUS BOX 119,BOULDER,CO 80309, 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 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 15 PY 1997 VL 24 IS 16 BP 2031 EP 2034 DI 10.1029/97GL01960 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XR464 UT WOS:A1997XR46400017 ER PT J AU Jelenkovic, BM Gallagher, A AF Jelenkovic, BM Gallagher, A TI Particle accumulation in a flowing silane discharge SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LOW-PRESSURE DISCHARGES; POWDER FORMATION; GLOW-DISCHARGE; PARTICULATE CONTAMINATION; RADIOFREQUENCY DISCHARGE; LIGHT-SCATTERING; PLASMAS; GROWTH; TRANSPORT; DUST AB Particle trapping in different areas of a parallel-plate, radio frequency silane discharge, and its effect on plasma optical emission of SiH and H-alpha, has been studied under high gas-flow and low power-density conditions, as used for ''device-quality'' hydrogenated amorphous silicon (a-Si:H) film deposition. The largest density of particles occurs between the electrodes, near the downstream corners of the rectangular electrodes. Particles are trapped in these positions by sheath fields, until reaching sufficient size to escape with the flow. The region of strong particle trapping has an increased intensity of optical emission, with H-alpha increased nearly fourfold. Slow oscillatory behavior of particle scattering and discharge emission was observed for pressures near 30 Pa. Power deposited in the discharge has also been measured; for a constant rf voltage and gas-flow speed it changes weakly with pressure, with the maximum at similar to 40 Pa. Combined with film growth-rate measurements, this yields a discharge energy deposition of similar to 17 eV per deposited Si atom. (C) 1997 American Institute of Physics. C1 UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NIST,BOULDER,CO. NR 32 TC 28 Z9 28 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 AUG 15 PY 1997 VL 82 IS 4 BP 1546 EP 1553 PG 8 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700008 ER PT J AU Molenbroek, EC Mahan, AH Gallagher, A AF Molenbroek, EC Mahan, AH Gallagher, A TI Mechanisms influencing ''hot-wire'' deposition of hydrogenated amorphous silicon SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID A-SI-H; DEVICE QUALITY; SILANE; DECOMPOSITION; FILMS AB Intrinsic hydrogenated amorphous silicon (a-Si:H) has been deposited using a hot tungsten filament in pure silane to drive the deposition chemistry-the ''hot-wire'' deposition method. The electronic and infrared properties of the film have been measured as a function of deposition parameters, leading to three principal conclusions. First, to obtain a high quality material, the Si atoms evaporated from the filament (distance L from the substrate) must react with silane (density n(s)) before reaching the substrate; this requires n(s)L greater than a critical value. Second, radical-radical reactions cause deterioration of him properties at high values of G(n(s)L),(3) where G is the film growth rate; this requires G(n(s)L)3 less than a critical value. Finally, the film quality is a function of G, and as G is increased the substrate temperature must be correspondingly increased to obtain high film quality. By optimizing these parameters, we have produced films with excellent electronic properties (e.g., ambipolar diffusion length >200 nm) at >5 nm/s deposition rate. Based on these insights, formulas are also given for optimizing film properties in multiple-filament geometries and in diluted silane. (C) 1997 American Institute of Physics. C1 NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. UNIV COLORADO,JILA,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. NR 16 TC 51 Z9 51 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 AUG 15 PY 1997 VL 82 IS 4 BP 1909 EP 1917 DI 10.1063/1.365998 PG 9 WC Physics, Applied SC Physics GA XQ797 UT WOS:A1997XQ79700059 ER PT J AU Bonisch, G Blindheim, J Bullister, JL Schlosser, P Wallace, DWR AF Bonisch, G Blindheim, J Bullister, JL Schlosser, P Wallace, DWR TI Long-term trends of temperature, salinity, density, and transient tracers in the central Greenland Sea SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID DEEP-WATER FORMATION; NORWEGIAN SEAS; ARCTIC-OCEAN; TRITIUM; RATES; CONVECTION; ICELAND AB We present long-term observations of temperature, salinity, tritium/He-3, chlorofluorocarbon-11 (CFC11), and chlorofluorocarbon-12 (CFC 12) for the central Greenland Gyre. The time series span the periods between 1952 and 1994 (temperature), 1981 and 1994 (salinity), 1972 and 1994 (tritium/He-3), and 1982 and 1994 (CFCs). The correlation between hydrographic and transient tracer data indicates that low temperatures in the deep water in the early 1950s and between 1960 and 1980 reflect periods of higher deep water formation rates whereas periods of increasing temperatures in the late 1950s and between 1980 and 1994 are related to low deep water formation rates. However, the transient tracer observations obtained in the 1980s and early 1990s indicate that even during periods of low deep water formation, some water from the upper water column contributed to deep water formation between 1980 and 1994. In 1994, the deep water reached temperatures and salinities of -1.149 degrees C and 34.899, respectively, and no longer fits most of the classical definitions of Greenland Sea Deep Water (-1.29 degrees C < Theta < -1.0 degrees C, 34.58 < S < 34.90). The temperature increase in the water column between 200 and 2000m depth between 1980 and 1994 corresponds to an average heating rate of about 5 W m(-2) over this period, resulting in a decrease in density. The 13-year warming could be balanced by intensive cooling in two winters. The surface salinity steadily increased from 34.50 in 1991 to 34.85 in 1994. C1 INST MARINE RES,N-5024 BERGEN,NORWAY. NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV OCEANOG & ATMOSPHER SCI,UPTON,NY 11973. COLUMBIA UNIV,DEPT EARTH & ENVIRONM SCI,NEW YORK,NY. RP Bonisch, G (reprint author), LAMONT DOHERTY EARTH OBSERV,PALISADES,NY 10964, USA. RI Schlosser, Peter/C-6416-2012 OI Schlosser, Peter/0000-0002-6514-4203 NR 35 TC 44 Z9 45 U1 0 U2 4 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 AUG 15 PY 1997 VL 102 IS C8 BP 18553 EP 18571 DI 10.1029/97JC00740 PG 19 WC Oceanography SC Oceanography GA XR356 UT WOS:A1997XR35600003 ER PT J AU Quinn, JB Quinn, GD AF Quinn, JB Quinn, GD TI Indentation brittleness of ceramics: A fresh approach SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID ELASTIC-PLASTIC INDENTATION; PRESSED SILICON-NITRIDE; FRACTURE-TOUGHNESS; CRACK-INITIATION; SINGLE-CRYSTALS; MICROHARDNESS; HARDNESS; LOAD; BEHAVIOR; DAMAGE AB The hardness and brittleness of ceramic materials are interrelated. Hard materials are more apt to fracture in the vicinity of an indentation during a hardness test, while softer materials tend to plastically deform to the indenter shape without fracturing. Measured hardness, in turn, is affected by both specimen deformation and fracture processes. This interrelationship is examined by means of extensive Vickers hardness testing. A new index of brittleness is proposed. C1 NATL INST STAND & TECHNOL,DIV CERAM,GAITHERSBURG,MD 20899. RP Quinn, JB (reprint author), UNIV MARYLAND,DEPT MAT ENGN,COLLEGE PK,MD 20742, USA. NR 80 TC 264 Z9 284 U1 4 U2 60 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD AUG 15 PY 1997 VL 32 IS 16 BP 4331 EP 4346 DI 10.1023/A:1018671823059 PG 16 WC Materials Science, Multidisciplinary SC Materials Science GA XT184 UT WOS:A1997XT18400022 ER PT J AU Pfister, O Wells, JS Hollberg, L Zink, L VanBaak, DA Levenson, MD Bosenberg, WR AF Pfister, O Wells, JS Hollberg, L Zink, L VanBaak, DA Levenson, MD Bosenberg, WR TI Continuous-wave frequency tripling and quadrupling by simultaneous three-wave mixings in periodically poled crystals: application to a two-step 1.19-10.71-mu m frequency bridge SO OPTICS LETTERS LA English DT Article ID LASER AB We observed cw third-harmonic generation in a periodically poled LiNbO3 crystal by cascading optimally phase-matched second-harmonic and sum-frequency generation. Other processes, such as fourth-harmonic generation, are allowed by the flexibility of quasi-phase matching. We demonstrate a divide-by-nine (1.19-10.71-mu m) frequency chain that uses only two lasers. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. RICE UNIV,DEPT ELECT & COMP ENGN,HOUSTON,TX 77251. LIGHTWAVE ELECT CORP,MT VIEW,CA 94043. CALVIN COLL,GRAND RAPIDS,MI 49546. RP Pfister, O (reprint author), UNIV COLORADO,NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. RI Pfister, Olivier/A-4924-2013 OI Pfister, Olivier/0000-0003-3386-9661 NR 16 TC 98 Z9 100 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD AUG 15 PY 1997 VL 22 IS 16 BP 1211 EP 1213 DI 10.1364/OL.22.001211 PG 3 WC Optics SC Optics GA XP167 UT WOS:A1997XP16700003 PM 18185797 ER PT J AU Bohn, JL AF Bohn, JL TI Theory of electron transport through a periodic array of devices with transverse exit leads SO PHYSICAL REVIEW B LA English DT Article ID QUANTUM BOUND-STATES; CONDUCTANCE; FIELD; WIRE; SUPERLATTICES; BEND; RESISTANCE; CHANNELS; WELLS; GAAS AB We introduce a periodic array of nanoscale semiconductor devices, where each device contains a transverse lead into which conduction electrons can be deflected. These ''deflective'' arrays exhibit a unique resonance structure with respect to electrons traveling the length of the array: coefficients for reflection and transmission through the array can peak simultaneously at resonance, unlike the analogous case in superlattices. We focus in particular on an array of T-shaped devices, similar to those grown recently by epitaxial methods, and characterized by perfection of structure and extremely small size. The T-array's nonlinear I-V characteristics, along with its multiple paths for electron flow, may lead to interesting switching applications. C1 NATL INST STAND & TECHNOL,QUANTUM PHYS DIV,BOULDER,CO 80309. RP Bohn, JL (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 43 TC 6 Z9 6 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 4132 EP 4140 DI 10.1103/PhysRevB.56.4132 PG 9 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400093 ER PT J AU Tanenbaum, DM Laracuente, AL Gallagher, A AF Tanenbaum, DM Laracuente, AL Gallagher, A TI Surface roughening during plasma-enhanced chemical-vapor deposition of hydrogenated amorphous silicon on crystal silicon substrates SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; SCANNING TUNNELING MICROSCOPE; FILM GROWTH; INSITU ELLIPSOMETRY; SIMULATION; INTERFACES; NUCLEATION AB The morphology of a series of thin films of hydrogenated amorphous silicon (a-Si:H) grown by plasma-enhanced chemical-vapor deposition (PECVD) is studied using scanning tunneling microscopy. The substrates were atomically flat, oxide-free, single-crystal silicon. Films were grown in a PECVD chamber directly connected to a surface analysis chamber with no air exposure between growth and measurement. The homogeneous roughness of the films increases with film thickness. The quantification of this roughening is achieved by calculation of both rms roughness and lateral correlation lengths of the a-Si:H film surface from the height difference correlation functions of the measured topographs. Homogeneous roughening occurs over the film surface due to the collective behavior of the flux of depositing radical species and their interactions with the growth surface. C1 NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. UNIV COLORADO,BOULDER,CO 80309. NR 51 TC 63 Z9 63 U1 2 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD AUG 15 PY 1997 VL 56 IS 7 BP 4243 EP 4250 DI 10.1103/PhysRevB.56.4243 PG 8 WC Physics, Condensed Matter SC Physics GA XR964 UT WOS:A1997XR96400105 ER PT J AU Williams, DF Belquin, JM Spisser, A Cappy, A Dambrine, G AF Williams, DF Belquin, JM Spisser, A Cappy, A Dambrine, G TI Characterisation of coplanar waveguide on epitaxial layers SO ELECTRONICS LETTERS LA English DT Article DE coplanar waveguides; indium phosphide AB The effect of thin AlInAs/GaInAs epitaxial layers on the propagation of electrical signals in coplanar waveguide transmission lines fabricated semi-insulating indium phosphide substrates is examined. It is shown that argon isolation implants effectively reduce conduction losses in these layers to negligible levels at radio, microwave. and millimetre-wave frequencies. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. IEMN, F-59652 Villeneuve Dascq, France. RP Williams, DF (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. EM dylan@bldrdoc.gov RI CAPPY, Alain/H-7773-2016 OI CAPPY, Alain/0000-0002-1811-1054 NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD AUG 14 PY 1997 VL 33 IS 17 BP 1468 EP 1469 DI 10.1049/el:19970969 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA YX448 UT WOS:000072041000031 ER PT J AU Lene, B Grymes, J AF Lene, B Grymes, J TI Heat-related deaths - Dallas, Wichita, and Cooke Counties, Texas, and United States, 1996 (Reprinted from MMWR, vol 46, pg 528-531, 1997) SO JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION LA English DT Reprint C1 NATL WEATHER SERV,FORECAST OFF,FT WORTH,TX. LOUISIANA STATE UNIV,SO REG CLIMATE CTR,BATON ROUGE,LA 70803. CDC,HLTH STUDIES BRANCH,ATLANTA,GA 30333. CDC,SURVEILLANCE & PROGRAMS BRANCH,DIV ENVIRONM HAZARDS & HLTH EFFECTS,NATL CTR ENVIRONM HLTH,ATLANTA,GA 30333. RP Lene, B (reprint author), SW INST FORENS SCI,DALLAS,TX, USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU AMER MEDICAL ASSOC PI CHICAGO PA 515 N STATE ST, CHICAGO, IL 60610 SN 0098-7484 J9 JAMA-J AM MED ASSOC JI JAMA-J. Am. Med. Assoc. PD AUG 13 PY 1997 VL 278 IS 6 BP 462 EP 463 PG 2 WC Medicine, General & Internal SC General & Internal Medicine GA XP243 UT WOS:A1997XP24300011 ER PT J AU Ji, XH Tordova, M ODonnell, R Parsons, JF Hayden, JB Gilliland, GL Zimniak, P AF Ji, XH Tordova, M ODonnell, R Parsons, JF Hayden, JB Gilliland, GL Zimniak, P TI Structure and function of the xenobiotic substrate-binding site and location of a potential non-substrate-binding site in a class pi glutathione S-transferase SO BIOCHEMISTRY LA English DT Article ID 3-DIMENSIONAL STRUCTURE; CRYSTAL-STRUCTURE; CHEMICAL HEPATOCARCINOGENESIS; MACROMOLECULAR STRUCTURES; ANGSTROM RESOLUTION; OPTICAL ENANTIOMERS; HUMAN PLACENTA; ACTIVE-SITE; MOUSE-LIVER; COMPLEX AB Complex structures of a naturally occurring variant of human class pi glutathione S-transferase 1-1 (hGSTP1-1) with either S-hexylglutathione or (9R,10R)-9-(S-glutathionyl)-10-hydroxy-9,10-dihydrophenanthrene [(9R,10R)-GSPhen] have been determined at resolutions of 1.8 and 1.9 Angstrom, respectively. The crystal structures reveal that the xenobiotic substrate-binding site (H-site) is located at a position similar to that observed in class mu GST 1-1 from rat liver (rGSTM1-1). In rGSTM1-1, the H-site is a hydrophobic cavity defined by the side chains of Y6, W7, V9, L12, I111, Y115, F208, and S209. In hGSTP1-1, the cavity is approximately half hydrophobic and half hydrophilic and is defined by the side chains of Y7, F8, V10, R13, V104, Y108, N204, and G205 and five water molecules. A hydrogen bond network connects the five water molecules and the side chains of R13 and N204. V104 is positioned such that the introduction of a methyl group (the result of the V104I mutation) disturbs the H-site water structure and alters the substrate-binding properties of the isozyme. The hydroxyl group of Y7 forms a hydrogen bond (3.2 Angstrom) with the sulfur atom of the product. There is a short hydrogen bond (2.5 Angstrom) between Y108 (OH) and (9R, 10R)-GSPhen (O5), indicating the hydroxyl group of Y108 as an electrophilic participant in the addition of glutathione to epoxides. An N-(2-hydroxethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) molecule is found in the cavity between beta 2 and alpha I. The location and properties of this HEPES-binding site fit a possible non-substrate-binding site that is involved in noncompetitive inhibition of the enzyme. C1 UNIV MARYLAND,INST BIOTECHNOL,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NATL INST STAND & TECHNOL,ROCKVILLE,MD 20850. VANDERBILT UNIV,SCH MED,DEPT BIOCHEM,NASHVILLE,TN 37232. VANDERBILT UNIV,SCH MED,CTR MOL TOXICOL,NASHVILLE,TN 37232. UNIV ARKANSAS MED SCI,DEPT MED,LITTLE ROCK,AR 72205. UNIV ARKANSAS MED SCI,DEPT BIOCHEM & MOL BIOL,LITTLE ROCK,AR 72205. JOHN L MCCLELLAN MEM VET ADM MED CTR,LITTLE ROCK,AR 72205. RP Ji, XH (reprint author), NCI,FREDERICK CANC RES & DEV CTR,ABL BASIC RES PROGRAM,FREDERICK,MD 21702, USA. RI Ji, Xinhua/C-9664-2012 OI Ji, Xinhua/0000-0001-6942-1514 FU NIEHS NIH HHS [ES07804]; NIGMS NIH HHS [R01 GM30910] NR 70 TC 78 Z9 79 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD AUG 12 PY 1997 VL 36 IS 32 BP 9690 EP 9702 DI 10.1021/bi970805s PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA XQ760 UT WOS:A1997XQ76000008 PM 9245401 ER PT J AU Stansbury, JW Liu, DW Kim, SI AF Stansbury, JW Liu, DW Kim, SI TI Polymer-supported quinuclidinyl catalysts for synthesis of cyclopolymerizable monomers via the aldehyde-acrylate coupling reaction SO MACROMOLECULES LA English DT Article ID MULTIFUNCTIONAL MONOMERS; ALPHA-(HYDROXYMETHYL)ACRYLATES; ESTERS AB With an appropriate amine catalyst, formaldehyde addition to acrylates results in alpha-hydroxymethyl acrylate intermediates that undergo a further condensation reaction to provide ether-linked 1,6-diene monomers capable of efficient cyclopolymerization. While 1,4-diazabicyclo[2.2.2]octane (DABCO) is an effective catalyst in the synthesis of these cyclopolymerizable monomers, a series of polymer-supported amine catalysts were prepared and evaluated in an effort to further simplify this process. 3-Quinuclidinol was reacted with methacrylic anhydride to give the functionalized methacrylate monomer, which was copolymerized with methyl methacrylate and triethylene glycol dimethacrylate. Various polymerization techniques (bulk, solution, and suspension) were used to produce the cross-linked polymeric catalysts. Supports with mole fractions of catalyst ranging from 20% to 98% were examined. In reactions with ethyl acrylate and paraformaldehyde, certain polymer-supported catalysts gave near quantitative conversion to products. The rate of reaction with the polymeric catalysts was less than that of reactions with DABCO or other nonpolymeric model catalysts; however, after reaction times of 20 h, product yields and distributions were quite similar. With the polymeric catalysts, product isolation required only simple filtration or a solvent wash rather than an aqueous extraction step. This technique was also applied to the preparation of cyclopolymerizable resins containing multifunctional oligomers. RP Stansbury, JW (reprint author), NIST,DIV POLYMERS,DENTAL & MED MAT GRP,GAITHERSBURG,MD 20899, USA. NR 16 TC 2 Z9 2 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD AUG 11 PY 1997 VL 30 IS 16 BP 4540 EP 4543 DI 10.1021/ma970053+ PG 4 WC Polymer Science SC Polymer Science GA XQ824 UT WOS:A1997XQ82400005 ER PT J AU Liu, XD Bauer, BJ Briber, RM AF Liu, XD Bauer, BJ Briber, RM TI Conformation of free linear polymer chains in a polymer network SO MACROMOLECULES LA English DT Article ID SMALL-ANGLE NEUTRON; SELF-AVOIDING WALKS; X-RAY-SCATTERING; POLYVINYL METHYL-ETHER); DEUTERATED POLYSTYRENE; POROUS-MEDIA; BLENDS; DIFFUSION; SWOLLEN; GELS AB Small angle neutron scattering has been used to measure the radius of gyration of deuterated linear polystyrene at dilute concentration contained in a polystyrene network with different crosslink densities. At each crosslink density, four samples with different linear chain concentrations (less than the overlap concentration) were made. The lower crosslink density samples (N-c>180) remained single phase, while higher crosslink density samples showed evidence of phase separation. Zimm plots were made for all samples which were single phase, and the second virial coefficient was obtained as a function of crosslink density. It was found that the second virial coefficient decreased with increasing crosslink density. Single chain form factors were obtained by extrapolating the scattering data to zero concentration of the linear chain for the single phase samples. A modified Debye equation was used to fit the zero concentration extrapolated scattering data over the entire experimental q range to obtain the radius of gyration, R-g, for the linear chain. It was found that R-g was a function of the crosslink density. When the crosslink density was low (N-c > N-l), R-g did not change appreciably and had a value nearly the same as in the melt. For higher cross-link density samples (N-c < N-l), R-g was found to decrease with increasing crosslink density and the scaling relation R-g(-1) similar to N-c(-1) was observed. Chain segregation was observed for the highest crosslink density samples. The dependence of R-g, on crosslink density can be qualitatively explained using a theory for the conformation of polymer chain in a random media. For the phase separated samples, a two correlation length theory was used to fit the scattering data. C1 UNIV MARYLAND, DEPT MAT & NUCL ENGN, COLLEGE PK, MD 20742 USA. NATL INST STAND & TECHNOL, DIV POLYMERS, GAITHERSBURG, MD 20899 USA. RI Briber, Robert/A-3588-2012 OI Briber, Robert/0000-0002-8358-5942 NR 57 TC 11 Z9 11 U1 3 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 EI 1520-5835 J9 MACROMOLECULES JI Macromolecules PD AUG 11 PY 1997 VL 30 IS 16 BP 4704 EP 4712 DI 10.1021/ma960864y PG 9 WC Polymer Science SC Polymer Science GA XQ824 UT WOS:A1997XQ82400029 ER PT J AU Lu, ZT Corwin, KL Vogel, KR Wieman, CE Dinneen, TP Maddi, J Gould, H AF Lu, ZT Corwin, KL Vogel, KR Wieman, CE Dinneen, TP Maddi, J Gould, H TI Efficient collection of Fr-221 into a vapor cell magneto-optical trap SO PHYSICAL REVIEW LETTERS LA English DT Article ID ATOMIC-BEAM; LASER; ISOTOPES; FRANCIUM AB We have efficiently loaded a vapor cell magneto-optical trap from an orthotropic source of Fr-221 with a trapping efficiency of 56(10)%. A novel detection scheme allowed us to measure 900 trapped atoms with a signal to noise ratio of similar to 60 in 1 sec. We have measured the energies and the hyperfine constants of the 7(2)P(1/2) and 7(2)P(3/2) states. C1 UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Lu, ZT (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. RI Corwin, Kristan/A-1331-2013 NR 23 TC 76 Z9 76 U1 2 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD AUG 11 PY 1997 VL 79 IS 6 BP 994 EP 997 DI 10.1103/PhysRevLett.79.994 PG 4 WC Physics, Multidisciplinary SC Physics GA XP977 UT WOS:A1997XP97700009 ER PT J AU Lovelace, RVE Zweibel, EG AF Lovelace, RVE Zweibel, EG TI Warp stability of magnetically supported disks SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; MHD; stars, pre-main-sequence AB Cold, magnetically supported, self-gravitating disks are evolutionary precursors of protostars. Magnetic tension balances self-gravity in these systems, so the magnetic field lines kink as they cross the disk. Previously, we have shown that such disks are marginally stable to in-plane perturbations. Here, we show that a sufficient condition for stability of such disks to out-of-plane, warping or tilting, perturbations is that the azimuthal current in the disk have one polarity as a function of radius. This corresponds to the gravitational acceleration in the disk pointing radially inward for all radii. This criterion is not necessary, however, and can be violated as long as the vertical magnetic field exceeds the radial magnetic field (in magnitude) everywhere in the disk. C1 UNIV COLORADO,DEPT ASTROPHYS & PLANETARY SCI,BOULDER,CO 80309. JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. RP Lovelace, RVE (reprint author), CORNELL UNIV,DEPT ASTRON,ITHACA,NY 14853, USA. NR 12 TC 6 Z9 6 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1997 VL 485 IS 1 BP 285 EP 289 DI 10.1086/304419 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XR037 UT WOS:A1997XR03700027 ER PT J AU Hobbie, EK Han, CC AF Hobbie, EK Han, CC TI Lattice model of a hydrogen-bonded polymer blend (vol 105, pg 738, 1996) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Correction, Addition RP Hobbie, EK (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. RI Hobbie, Erik/C-8269-2013 NR 1 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 8 PY 1997 VL 107 IS 6 BP 2162 EP 2163 DI 10.1063/1.474566 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XP280 UT WOS:A1997XP28000049 ER PT J AU Wheeler, AA McFadden, GB AF Wheeler, AA McFadden, GB TI On the notion of a xi-vector and a stress tensor for a general class of anisotropic diffuse interface models SO PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article ID PHASE-FIELD MODELS; BOUNDARY MOTION; ORDER-PARAMETER; GRADIENT FLOWS; TRANSITIONS; THERMODYNAMICS; SURFACES; DYNAMICS; GROWTH AB We show that, under equilibrium conditions, an anisotropic phase-field model of a diffuse interface leads to the notion of a divergence-free tensor, whose components are negligible away from the interface. Near the interface, it plays the role of a stress tensor, and involves the phase-field generalization of the Cahn-Hoffman xi-vector. We show that this tensor may be used to derive the equilibrium conditions for edges in interfaces. We then extend these ideas from the phase-field model to a general class of multiple-order-parameter models. In this broader context, we demonstrate that it is also possible to construct a xi-vector and we use it to derive the three-dimensional form of the Gibbs-Thomson equation in the sharp-interface limit. We derive the associated stress tensor for the multiple-order-parameter case and show that it also leads to the appropriate equilibrium conditions for edges in interfaces and multiple junctions in the sharp-interface limit. This approach shows that both multiple-order-parameter models and less physically based phase-field models share a common framework, the former providing a generalization of the notion of the xi-vector for phase-field models as well as providing a connection to the classical xi-vector theory for a sharp interface. For the special case of a phase-field model with non-convex surface energy, we show that edges can be represented by weak shocks in which the spatial derivatives of the phase field are not continuous, and we derive the associated jump conditions. In all the situations considered the notion of the xi-vector and the stress tensor play a central role. C1 NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. RP Wheeler, AA (reprint author), UNIV SOUTHAMPTON, FAC MATH STUDIES, SOUTHAMPTON SO17 1BJ, HANTS, ENGLAND. RI McFadden, Geoffrey/A-7920-2008 OI McFadden, Geoffrey/0000-0001-6723-2103 NR 48 TC 50 Z9 50 U1 1 U2 9 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-5021 EI 1471-2946 J9 P ROY SOC A-MATH PHY JI Proc. R. Soc. A-Math. Phys. Eng. Sci. PD AUG 8 PY 1997 VL 453 IS 1963 BP 1611 EP 1630 PG 20 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XQ910 UT WOS:A1997XQ91000003 ER PT J AU Kraus, SD Read, AJ Solow, A Baldwin, K Spradlin, T Anderson, E Williamson, J AF Kraus, SD Read, AJ Solow, A Baldwin, K Spradlin, T Anderson, E Williamson, J TI Acoustic alarms reduce porpoise morality SO NATURE LA English DT Letter C1 DUKE UNIV,MARINE LAB,BEAUFORT,NC 28516. WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543. UNIV NEW HAMPSHIRE,DEPT OCEAN ENGN,DURHAM,NH 03824. NATL MARINE FISHERIES SERV,OFF PROTECTED RESOURCES,SILVER SPRING,MD 20910. NEW HAMPSHIRE COMMERCIAL FISHERMENS ASSOC,RYE,NH 03780. RP Kraus, SD (reprint author), NEW ENGLAND AQUARIUM,EDGERTON RES LAB,CENT WHARF,BOSTON,MA 02110, USA. NR 9 TC 106 Z9 120 U1 1 U2 13 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD AUG 7 PY 1997 VL 388 IS 6642 BP 525 EP 525 DI 10.1038/41451 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XP722 UT WOS:A1997XP72200028 ER PT J AU Takahashi, T Feely, RA Weiss, RF Wanninkhof, RH Chipman, DW Sutherland, SC Takahashi, TT AF Takahashi, T Feely, RA Weiss, RF Wanninkhof, RH Chipman, DW Sutherland, SC Takahashi, TT TI Global air-sea flux of CO2: An estimate based on measurements of sea-air pCO(2) difference SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT Colloquium on Carbon Dioxide and Climate Change CY NOV 13-15, 1995 CL NATL ACAD SCI, IRVINE, CA HO NATL ACAD SCI ID ATMOSPHERIC CARBON-DIOXIDE; EQUATORIAL PACIFIC; PARTIAL-PRESSURE; NORTH-ATLANTIC; SURFACE WATERS; OCEAN-CIRCULATION; TROPICAL ATLANTIC; EL-NINO; EXCHANGE; MODEL AB Approximately 250,000 measurements made for the pCO(2) difference between surface water and the marine atmosphere, Delta pCO(2), have been assembled for the global oceans. Observations made in the equatorial Pacific during El Nine events have been excluded from the data set, These observations are mapped on the global 4 degrees x 5 degrees grid for a single virtual calendar year (chosen arbitrarily to be 1990) representing a non-El Nino year. Monthly global distributions of Delta pCO(2) have been constructed using an interpolation method based on a lateral advection-diffusion transport equation. The net flux of CO2 across the sea surface has been computed using Delta pCO(2) distributions and CO2 gas transfer coefficients across sea surface. The annual net uptake flux of CO2 by the global oceans thus estimated ranges from 0.60 to 1.34 Gt-C.yr(-1) depending on different formulations used for wind speed dependence on the gas transfer coefficient, These estimates;Ire subject to an error of up to 75% resulting from the numerical interpolation method used to estimate the distribution of Delta pCO(2) over the global oceans, Temperate and polar oceans of the both hemispheres are the major sinks for atmospheric CO2, whereas the equatorial oceans are the major sources for CO2. The Atlantic Ocean is the most important CO2 sink, providing about 60% of the global ocean uptake, while the Pacific Ocean is neutral because of its equatorial source flux being balanced by the sink flux of the temperate oceans, The Indian and Southern Oceans take up about 20% each. C1 NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093. NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33149. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP Takahashi, T (reprint author), COLUMBIA UNIV,LAMONT DOHERTY EARTH OBSERV,PALISADES,NY 10964, USA. NR 74 TC 312 Z9 323 U1 2 U2 38 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD AUG 5 PY 1997 VL 94 IS 16 BP 8292 EP 8299 DI 10.1073/pnas.94.16.8292 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XQ124 UT WOS:A1997XQ12400005 PM 11607736 ER PT J AU Lee, KB Eccles, LH Malchodi, L AF Lee, KB Eccles, LH Malchodi, L TI The IEEE P1451.2: A smart transducer interface for sensors and actuators SO ELECTRONIC DESIGN LA English DT Article RP Lee, KB (reprint author), NATL INST STAND & TECHNOL,BLDG 233,ROOM B102,GAITHERSBURG,MD 20899, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PENTON PUBL INC PI CLEVELAND PA 1100 SUPERIOR AVE, CLEVELAND, OH 44114 SN 0013-4872 J9 ELECTRON DES JI Electron. Des. PD AUG 4 PY 1997 VL 45 IS 16 BP 97 EP & PG 6 WC Engineering, Electrical & Electronic SC Engineering GA XP693 UT WOS:A1997XP69300018 ER EF