James A. Warren、J. S. Langer1990-09-01Physical Review A
We propose an approximate method for studying steady-state properties and linear stability of the dendritic arrays that are formed in directional solidification of alloys. Our analysis is valid at high growth rates where the primary spacing between dendrites is larger than the velocity-dependent solutal diffusion leng…
Aluminum Alloy Microstructure PropertiesSolidification and crystal growth phenomenananoparticles nucleation surface interactions
Tilak P. Wijesekera、Akiteru Matsumoto、David Dolphin 等 4 位作者1990-09-01Angewandte Chemie International Edition in English
The electron-withdrawing chloro substituents in the porphinatoiron(III) compounds 2–6 cause anodic shifts in the half-wave potentials E1/2 relative to that of the unsubstituted compound 1. Substitution on the phenyl rings is less effective than β substitution (R3). The spectroelectrochemically determined stability con…
Porphyrin and Phthalocyanine ChemistryHeme Oxygenase-1 and Carbon MonoxidePorphyrin Metabolism and Disorders
G. Beamson、D. Briggs、S. F. Davies 等 9 位作者1990-09-01Surface and Interface Analysis
Abstract The Scienta ESCA300 is a state‐of‐the‐art x‐ray photoelectron spectrometer with high intensity, and high energy and spatial resolution. This unique combination of features is made possible by the use of a high‐power rotating anode x‐ray source with monochromatization, high transmission and imaging electron op…
X-ray Spectroscopy and Fluorescence AnalysisNuclear Physics and ApplicationsElectron and X-Ray Spectroscopy Techniques
Chisato Nojiri、Teruo Okano、Harvey Jacobs 等 7 位作者1990-09-01Journal of Biomedical Materials Research
HEMA/styrene (HEMA/STY) block copolymers and poly(ethylene oxide) 4,000 M.W. (PEO4K) grafted Biomer (B-PEO4K) surfaces have been synthesized, characterized, and evaluated as blood-contacting materials. These surfaces have demonstrated improved blood compatibility, compared to Biomer, in in vitro and ex vivo experiment…
Electrospun Nanofibers in Biomedical ApplicationsPolymer Surface Interaction Studies
David B. Marshall、M.C. Shaw、Reinhold H. Dauskardt 等 6 位作者1990-09-01Journal of the American Ceramic Society
Transformation zones surrounding cracks in several toughened magnesia‐partially‐stabilized zirconia ceramics are characterized by optical interference measurements of surface uplift and by Raman microprobe spectroscopy. The measurements demonstrate that the volume fraction of transformation is nonuniform within the zo…
Advanced ceramic materials synthesisNuclear Materials and PropertiesAdvanced materials and composites
K. L. Moazed、J.R. Zeidler、Michael Taylor1990-09-01Journal of Applied Physics
Techniques have been developed to produce ohmic contacts to naturally occurring boron doped semiconducting diamond. Thin films of Mo, Mo/Au, and Mo/Ni/Au deposited on diamond produced adherent ohmic contacts after annealing at 950 °C. A thermally activated solid state reaction which produces a refractory carbide preci…
Metal and Thin Film MechanicsDiamond and Carbon-based Materials ResearchForce Microscopy Techniques and Applications
Jeanette C. Roberts、Yvonne E. Adams、Donald A. Tomalia 等 5 位作者1990-09-01Bioconjugate Chemistry
Starburst dendrimers, spherical polymers constructed from methyl acrylate and ethylenediamine, were successfully used to covalently couple synthetic porphyrins to antibody molecules. The dendrimers, as linker molecules, have great potential for increasing the specific activity of radiolabeled antibodies for tumor ther…
RNA Interference and Gene DeliveryMonoclonal and Polyclonal Antibodies ResearchDendrimers and Hyperbranched Polymers
Hans Preusting、Atze Nijenhuis、Bernard Witholt1990-09-01Macromolecules
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhysical characteristics of poly(3-hydroxyalkanoates) and poly(3-hydroxyalkenoates) produced by Pseudomonas oleovorans grown on aliphatic hydrocarbonsHans Preusting, Atze Nijenhuis, and Bernard WitholtCite this: Macromolecules 1990, 23, 19, 4220–4224Publication Date (Print):…
biodegradable polymer synthesis and propertiesMicroplastics and Plastic PollutionCarbon dioxide utilization in catalysis
G. Barbero、E. Miraldi、A. Stepanescu1990-09-01Journal of Applied Physics
The size and surface effects on the nematic-isotropic phase transition of a liquid crystal are analyzed using a functional form of the surface energy proportional to the square of the scalar order parameter. The evaluated temperature shift agrees with the published experimental observations. This form seems confirmed…
Liquid Crystal Research AdvancementsMaterial Dynamics and PropertiesPhotonic Crystals and Applications
Lech Longa、Hans‐Rainer Trebin1990-09-01Physical Review A
A phenomenological theory of polar structures in chiral biaxial liquid crystals is constructed exploiting the properties of a symmetric and traceless tensor order parameter field ${\mathit{Q}}_{\mathrm{\ensuremath{\alpha}}\mathrm{\ensuremath{\beta}}}$(r) and of a polar field ${\mathit{P}}_{\mathrm{\ensuremath{\alpha}}…
Liquid Crystal Research AdvancementsNonlinear Dynamics and Pattern FormationPlant Reproductive Biology
Raj K. Gupta、R. R. Singh、Kenneth K. Tanji1990-09-01Soil Science Society of America Journal
Abstract Calcareous sodic soils having high sodicity and high pH often maintain high solution P concentration. The effect of high exchangeable Na, high pH, and alkali anions and carbonates on the release of inorganic P was investigated in soils representing the three major benchmark sodic soil series found in the Indo…
Soil Carbon and Nitrogen DynamicsSoil and Unsaturated FlowClay minerals and soil interactions
Heinz‐S. Kitzerow、P. P. Crooker、Samuel Kwok 等 5 位作者1990-09-01Physical Review A
Electric fields can cause structural changes of the blue phases (BP) that appears in chiral liquid crystals. In BP I and BP II, electrostrictive effects cause a shift of the Bragg reflection wavelengths with little intensity change. In BP III, for systems with negative dielectric anisotropy, there is a strong increase…
Liquid Crystal Research AdvancementsOptical Polarization and EllipsometryMolecular spectroscopy and chirality
Elvira D. Guevarra、Takeshi Tabuchi1990-09-01Agricultural and Biological Chemistry
Many strains of the genus Ustilago were found to be good producers of organic acids, that is, itaconic, l-itatartaric, l-2-hydroxyparaconic, and l-malic acids. Itatartaric and 2-hydroxyparaconic acids were invariably produced together with itaconic acid. From these findings and the results of the experiments with perm…
Algal biology and biofuel productionDiatoms and Algae ResearchMicrobial Metabolites in Food Biotechnology
Pantcho Stoyanov、Sohail Akhter、John White1990-09-01Surface and Interface Analysis
Abstract The interaction between in situ evaporated aluminum and plyvinyl alcohol (PVA) polymer at 300 K was studied by XPS. The aluminum condenses on the PVA surface by a Volmer–Weber (clustering) mechanism; it takes about a 3.7 monolayer deposition to nucleate clusters sufficiently large to exhibit core binding ener…
Electron and X-Ray Spectroscopy TechniquesIon-surface interactions and analysisSurface and Thin Film Phenomena
J. Suchanicz、W Ptak1990-09-01Ferroelectrics Letters Section
The existence of polar regions in Na0.5Bi0.5Tio3 and pyroelectric measurements. Both dynamics and sizes of these regions depend on temperature and time.
Ferroelectric and Piezoelectric MaterialsMultiferroics and related materialsMicrowave Dielectric Ceramics Synthesis
D. M. Szmyd、P. Porro、A. Majerfeld 等 4 位作者1990-09-01Journal of Applied Physics
A systematic study of the photoluminescence (PL) of Se-doped n-type GaAs grown by metalorganic chemical vapor deposition is reported. A new method is presented to determine the electron effective mass of n+-direct-gap semiconductors from the PL spectrum. GaAs samples with electron densities from 1015 to 8×1018 cm−3 we…
Semiconductor Quantum Structures and DevicesZnO doping and propertiesChalcogenide Semiconductor Thin Films
Michael R. Hyman、Chang‐Yub Kim、Daniel J. Arp1990-09-01Journal of Bacteriology
Carbon disulfide has long been recognized as a potent inhibitor of nitrification, and it is the likely active component in several nitrification inhibitors suitable for field use. The effects of this compound on Nitrosomonas europaea have been investigated, and the site of action has been determined. Low concentration…
Nitric Oxide and Endothelin EffectsElectrochemical sensors and biosensorsAdvanced Nanomaterials in Catalysis
E. Batawi、D.G. Morris、M.A. Morris1990-09-01Materials Science and Technology
The mechanical properties of as well as microstructural changes in rapidly solidified ternary Cu–Cr based alloys were studied for various ternary additions. The flow stresses of the binary and various ternary alloys are explained in terms of Orowan strengthening mechanisms. Zirconium, magnesium, and, to a lesser exten…
Microstructure and mechanical propertiesMetallurgy and Material FormingAdvanced materials and composites
Ellen Ivers‐Tiffée、W. Wersing、M. Schießl 等 4 位作者1990-09-01Berichte der Bunsengesellschaft für physikalische Chemie
Abstract We present a planar cell design for Solid Oxide Fuel Cells (SOFC) which combines the ceramic materials of a solid electrolyte (Y‐stabilized ZrO 2 ), cathode (LaSrMeO 3 with Me : Mn, Co and Cr), and anode (Ni‐Cermet) with a metallic interconnection material, the so‐called metallic bipolar plate. This metallic…
Electrocatalysts for Energy ConversionAdvancements in Solid Oxide Fuel CellsFuel Cells and Related Materials
Geoffrey B. Smith1990-09-01Applied Optics
The transmittance T and reflectance R of s- and p-polarized light, incident at various angles onto thin films which contain metal and voids in an oblique columnar structure, are analyzed using suitably modified thin film equations. Columnar aluminum is treated for various column angles in uniaxial and biaxial models t…
Liquid Crystal Research AdvancementsPhotonic Crystals and ApplicationsOptical Coatings and Gratings