Materials Literature
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The directed oxidation of some molten aluminum alloys was studied. Alloys containing Si, Zn, and Mg are readily converted into Al 2 O 3 /Al composites with the characteristic directed metal oxidation process (DIMOX) metal‐channel structure. No reaction took place when alloys without Mg were used. However, when Mg‐free…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemistry and spectroelectrochemistry of 1,8-naphthalene- and 1,8-anthracene-linked cofacial binuclear metallophthalocyanines. New mixed-valence metallophthalocyaninesNagao Kobayashi, Herman Lam, W. Andrew Nevin, Pavel Janda, Clifford C. Leznoff, and A. B. P. LeverCit…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAssembly of high-valent oxomanganese clusters in aqueous solution. Redox equilibrium of water-stable Mn3O44+ and Mn2O23+ complexesJoseph E. Sarneski, H. Holden Thorp, Gary W. Brudvig, Robert H. Crabtree, and Gayle K. SchulteCite this: J. Am. Chem. Soc. 1990, 112, 20, 7255–72…
Abstract Until recently, the determination of the defect structures (previously referred to incorrectly as “crystallinity”) of kaolinites has been obtained in one of two ways: (1) measurement of the Hinckley index, or (2) by comparing calculated X-ray diffraction patterns based on a model of the defect structure (incl…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheoretical study of transition-metal hydrides. 5. Hafnium to mercury (HfH+ through HgH+), barium and lanthanum (BaH+ and LaH+)Gilles Ohanessian, Mark J. Brusich, and William A. Goddard IIICite this: J. Am. Chem. Soc. 1990, 112, 20, 7179–7189Publication Date (Print):Septembe…
Reflection high-energy electron diffraction (RHEED) is an experimentally simple technique, and yet a powerful one for examining the structure of a substrate surface and for monitoring the surface crystal structure and the crystallographic orientation of thin films during their growth. However, it can be difficult to l…
Abstract Infrared spectra of syndiotactic polystyrene exhibiting various crystalline forms and modifications, and in the amorphous state, are reported in this contribution. In addition to strong conformational effects, the spectra demonstrate striking effects of chain packing. Several infrared spectral differences als…
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…
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…
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…
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…
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…
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…
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…
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):…
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…
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}}…
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…
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…
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…