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第 181008 / 186559 页 · 当前展示 3,620,141–3,620,160 / 3,731,168 条匹配结果 · 摘要仅作预览

Continuous Existence of Bismuth at Grain Boundaries of Zinc Oxide Varistor without Intergranular Phase

Kei‐Ichiro Kobayashi、Osamu Wada、Masahiro Kobayashi 等 4 位作者1998-08-01Journal of the American Ceramic Society

The state of Bi at the grain boundaries of ZnO varistors was analyzed using FE‐TEM with EDS point and mapping analysis with a spatial resolution of less than 1 nm. The continuous existence of Bi of less than 1/2 atomic layer has been confirmed at ZnO‐ZnO junctions without any secondary phase. The coexistence of a crys…

ZnO doping and propertiesGas Sensing Nanomaterials and SensorsCopper-based nanomaterials and applications

Study of CdTe etching process in alcoholic solutions of bromine

I. M. Kotina、L M Tukhkonen、G.V Patsekina 等 5 位作者1998-08-01Semiconductor Science and Technology

Changes in the structure and stoichiometry of the p-CdTe surface as a result of etching have been studied by high-resolution x-ray photoelectron spectroscopy and the Rutherford backscattering method. Etching with bromine-methanol and bromine-butanol solutions is shown to enrich the surface with elementary tellurium .…

Chalcogenide Semiconductor Thin FilmsAdvanced Semiconductor Detectors and MaterialsElectron and X-Ray Spectroscopy Techniques

Acetoacetyl Coenzyme A Reductase and Polyhydroxybutyrate Synthesis in Rhizobium ( Cicer ) sp. Strain CC 1192

Shahid N. Chohan、Les Copeland1998-08-01Applied and Environmental Microbiology

Biochemical controls that regulate the biosynthesis of poly-3-hydroxybutyrate (PHB) were investigated in Rhizobium (Cicer) sp. strain CC 1192. This species is of interest for studying PHB synthesis because the polymer accumulates to a large extent in free-living cells but not in bacteroids during nitrogen-fixing symbi…

Enzyme Catalysis and Immobilizationbiodegradable polymer synthesis and propertiesAmino Acid Enzymes and Metabolism

Charge dynamics and recombination kinetics in columnar discotic liquid crystals

N. Boden、Richard J. Bushby、J. Clements 等 6 位作者1998-08-01Physical review. B, Condensed matter

The time-dependent quasi-one-dimensional transport of electrons or holes along the molecular columns in columnar liquid crystals has been studied. Recent mobility measurements on the tryphenylene-based HAT-n materials have revealed Gaussian transits in the liquid crystalline phases but dispersion in the crystalline ph…

Liquid Crystal Research AdvancementsNonlinear Dynamics and Pattern FormationAdvanced Thermodynamics and Statistical Mechanics

Chemical reactions occurring in the thermal treatment of PC/PMMA blends

Giorgio Montaudo、Concetto Puglisi、Filippo Samperi1998-08-01Journal of Polymer Science Part A Polymer Chemistry

The chemical reactions occurring in the thermal treatment of bisphenol-A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) blends have been investigated by nuclear magnetic resonance (NMR), mass spectrometry (MS), size exclusion chromatography (SEC), and thermogravimetry (TG). Our results suggest that in the mel…

Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties

The effect of temperature on the elastic responses to longitudinal torsion of rectangular nickel titanium archwires.

Torstein R. Meling、Jan Ødegaard1998-08-01PubMed

To investigate responses to longitudinal torsion and the effect of temperature on the torsional stiffness of superelastic nickel titanium archwires, eight batches of rectangular wires were tested at 18, 27, 37, and 40 degrees C ambient temperature. The wires were twisted 25 degrees and studied in deactivation. The res…

Orthopedic Surgery and RehabilitationWelding Techniques and Residual StressesTitanium Alloys Microstructure and Properties

Multicomponent diffusion in the molten system K 2 O-Na 2 O-Al 2 O 3 -SiO 2 -H 2 O

James E. Mungall、Cláudia Romano、Donald B. Dingwell1998-08-01American Mineralogist

We have measured multicomponent chemical diffusion coefficients in a melt near to the low pressure water-saturated eutectic granite composition in the system K 2 O-Na 2 O-Al 2 O 3 -SiO 2 -H 2 O at 1.0 GPa and temperatures of 1300 and 1600 ℃. The measured diffusion profiles can be accounted for within the analytical er…

Glass properties and applicationsMetallurgical Processes and ThermodynamicsRecycling and utilization of industrial and municipal waste in materials production

Soluble fumarate reductase isoenzymes fromSaccharomyces cerevisiaeare required for anaerobic growth

Y. Arikawa、Keiichiro Enomoto、Haruhiro Muratsubaki 等 4 位作者1998-08-01FEMS Microbiology Letters

In Saccharomyces cerevisiae, the cytosolic and promitochondrial isoenzymes of fumarate reductase are encoded by the FRDS and OSM1 genes, respectively. The product of the OSM1 gene is reported to be required for growth in hypertonic medium. Simultaneous disruption of the FRDS and OSM1 genes resulted in the inability of…

Biofuel production and bioconversionFungal and yeast genetics researchEnzyme Structure and Function

Kinetic behavior analysis of porphyrin Langmuir–Blodgett films for conductive gas sensors

A. Tepore、A. Serra、D. Manno 等 6 位作者1998-08-01Journal of Applied Physics

Meso, meso′-buta-1,3-diyne-bridged Ni (II) octaethylporphyrin dimer thin films have been deposited by the Langmuir–Blodgett method and, for the first time, have been considered as the active layer in resistive gas sensors. In particular, the electrical conductivities of these films undergo a remarkable variation due t…

Lipid Membrane Structure and BehaviorPorphyrin and Phthalocyanine ChemistrySpectroscopy and Quantum Chemical Studies

SPIN-DEPENDENT TRANSPORT AND LOW-FIELD MAGNETORESISTANCE IN DOPED MANGANITES

J. Z. Sun、Alka Gupta1998-08-01Annual Review of Materials Science

▪ Abstract Doped manganite perovskites exhibit large magnetoresistance, but usually only in high fields (>1 Tesla). Efforts are under way to understand the underlying mechanism and to explore possibilities of achieving large magnetoresistance at low fields, which has led to focused studies of spin-dependent transpo…

Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsElectronic and Structural Properties of Oxides

Macropore Formation in Highly Resistive p‐Type Crystalline Silicon

Ralf B. Wehrspohn、J.‐N. Chazalviel、François Ozanam1998-08-01Journal of The Electrochemical Society

Macropore formation during anodization of highly resistive p‐type crystalline silicon in HF is reported for the first time. This formation is due to an instability of the dissolution attributed to the high resistivity of the silicon electrode as compared to that of the electrolyte, as it had been observed during anodi…

Semiconductor materials and devicesThin-Film Transistor TechnologiesSilicon Nanostructures and Photoluminescence

The average atomic volume and density of proteins

作者信息未提供1998-08-01Zeitschrift für Kristallographie - Crystalline Materials

Abstract The density of proteins is an important quantity. For ab initio phasing in X-ray crystallography, such as low resolution envelope techniques [1, 2], an accurate protein density is essential to get a correct prediction of the protein volume from the amino acid sequence. An accurate value will also facilitate t…

Protein Structure and DynamicsRNA and protein synthesis mechanismsEnzyme Structure and Function

Stress Rupture of an Enhanced Nicalon/Silicon Carbide Composite at Intermediate Temperatures

Todd E. Steyer、Frank W. Zok、D.P. Walls1998-08-01Journal of the American Ceramic Society

The stress rupture characteristics of an enhanced Nicalon/SiC composite at 900°C have been examined. This temperature has been identified as being in the regime wherein oxidation embrittlement is operative. The enhancement of the composite involves the use of a coating around the fiber tows, comprising a C‐rich matrix…

Advanced ceramic materials synthesisAluminum Alloys Composites PropertiesAdvanced materials and composites

Analysis of Cure Characteristics on Cross-Link Density and Type, and Viscoelastic Properties of Natural Rubber

Narongrit Sombatsompop1998-08-01Polymer-Plastics Technology and Engineering

The interrelation of degree and type of cross-linking and viscoelastic properties of sulfur-cured natural rubber (NR) vulcanizates was investigated by altering accelerator concentration, cure time, and cure temperature. Constants C 1 and C 2 from the Mooney-Rivlin equation were given via stress-strain measurement to e…

Polymer Nanocomposites and PropertiesPolymer composites and self-healingTribology and Wear Analysis

Local structure and electrical switching in chalcogenide glasses

Sevi Murugavel、S. Asokan1998-08-01Physical review. B, Condensed matter

Bulk ${\mathrm{Al}}_{x}{\mathrm{As}}_{40}{\mathrm{Te}}_{60\ensuremath{-}x}$ and ${\mathrm{Al}}_{x}{\mathrm{As}}_{40\ensuremath{-}x}{\mathrm{Te}}_{60}$ glasses $(5<~x<~20)$ are found to exhibit memory and threshold switching. ${}^{27}\mathrm{Al}$ solid-state NMR measurements reveal that in both series of glasses,…

Glass properties and applicationsPhase-change materials and chalcogenidesSolid-state spectroscopy and crystallography

Complex Dielectric Constant of Liquid Crystal Materials Containing Ionic Impurities in Low Frequency Region

Atsushi Sawada、Yuji Nakazono、Kazuaki Tarumi 等 4 位作者1998-08-01Molecular crystals and liquid crystals science technology. Section A, Molecular crystals and liquid crystals/Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals

The dielectric properties of liquid crystal materials containing ionic impurities are analyzed in terms of space charge polarization. The theoretical expressions of the dielectric constant and the dielectric loss factor are derived by solving a diffusion equation for mobile ions under an AC field. Numerical calculatio…

Liquid Crystal Research AdvancementsMaterial Dynamics and PropertiesPolymer Nanocomposites and Properties

Preparations and Properties of Poly(vinylsilane)s

Masayoshi Itoh、Kenji Iwata、Mineo Kobayashi 等 5 位作者1998-08-01Macromolecules

Three kinds of poly(vinylsilane)s, which include oligomers, were prepared by the polymerizations of vinylsilane [CH 2 CHSiH 3 ] using a radical initiator catalyst, an anionic catalyst, and a coordinated anionic catalyst (Ziegler−Natta catalyst). A colorless and transparent liquid polymer of molecular weight ( M n ) 50…

Mesoporous Materials and CatalysisSynthesis and characterization of novel inorganic/organometallic compoundsSilicone and Siloxane Chemistry

Density Functional Modeling of Double Exchange Interactions in Transition Metal Complexes. Calculation of the Ground and Excited State Properties of [Fe2(OH)3(tmtacn)2]2+

Vincenzo Barone、Alessandro Bencini、Ilaria Ciofini 等 5 位作者1998-08-01Journal of the American Chemical Society

Density functional theory has been successfully applied to characterize the electronic structure and the magnetic properties of the mixed valence dinuclear complex [Fe 2 (OH) 3 (tmtacn) 2 ] 2+ modeled by replacing the tmtacn ligand with three ammonia molecules. Spectroscopic and magnetic properties have been computed…

Advanced Chemical Physics StudiesMagnetism in coordination complexesMetal-Catalyzed Oxygenation Mechanisms

Effects of Hydrogen on Pitting Susceptibility of Type 310 Stainless Steel

Qimeng Yang、Lijie Qiao、S. Chiovelli 等 4 位作者1998-08-01CORROSION

Type 310 (UNS S31000) stainless steel (SS) membranes were precharged with hydrogen at various current densities. Effects of hydrogen on pitting susceptibility were investigated by carrying out the ASTM G 48 standard ferric chloride (FeCl3) tests. Changes in pit density, pit size distribution, average pit diameter (Da)…

Corrosion Behavior and InhibitionHydrogen embrittlement and corrosion behaviors in metalsNon-Destructive Testing Techniques

Anion-induced charge-transfer enhancement in SERS and SERRS spectra of Rhodamine 6G on a silver electrode: how important is it?

Wojciech Grochala、Andrzej Kudelski、J. Bukowska1998-08-01Journal of Raman Spectroscopy

An additional anion-induced enhancement of surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) for Rhodamine 6G adsorbed on a silver electrode upon addition of chloride and citrate anions was determined as a function of the applied potential. The observed increase in intens…

Gold and Silver Nanoparticles Synthesis and ApplicationsElectrochemical Analysis and ApplicationsProtein Interaction Studies and Fluorescence Analysis