Materials Literature
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The needle-shaped frustules of the diatoms Thalassionema Grunow and Thalassiothrix Cleve et Grunow are furnished with uniquely structured areolae which appear as a row of depressions along each edge of the valve. In Thalassionema the areolae open freely outwards and are surmounted by one to three simple silica branche…
The interference of scalar optical Floquet-Bloch waves in periodically stratified media is discussed in detail. Two main types of interference are identified and fully analyzed: normal and exchange interference, producing, respectively, real and virtual spatial fringes. In the paper considerable use is made of a recip…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetochemistry of copper(II): exchange interactions in catenated acetatodiamminebromocopperRichard L. Carlin, Klaas Kopinga, Olivier Kahn, and Michel VerdaguerCite this: Inorg. Chem. 1986, 25, 11, 1786–1789Publication Date (Print):May 1, 1986Publication History Published o…
Abstract Three hypotheses concerning the movement and retention of anions in forest soils were tested in a series of laboratory and field studies on two Tennessee Ultisols with mixed deciduous forest cover and two Washington Inceptisols, one with deciduous (red alder Alnus rubra Bong.) and one with coniferous [Douglas…
Chemical bonding and reaction of in situ deposited Ti on a series of polyimide surfaces have been investigated. X-ray photoelectron spectroscopy has been used to probe site specific information for bonding of various functional groups of polyimide molecules, while ultraviolet photoelectron spectroscopy has been applie…
Abstract Flexural properties of moldings made by Reaction Injection Molding (RIM), which are structural foams consisting of high density skin and low density core, were investigated by three‐point bending tests. Two failure modes were observed in bending tests of the moldings made by RIM, and they are classified as fo…
Photoelectron spectroscopy of adsorbed Xe (PAX) was used to characterize various Pt/TiO2 (100) surfaces on an atomic scale. The PAX data provide useful information on both geometrical and electronic states of various surface sites. For example, both Ar ion sputtering and high temperature annealing (850 °C) in vacuum p…
Among the first row transition metal oxides from V2O5 to ZnO, CuO was found to be the most easily reduced by hydrazine. CuO surfaces exposed to hydrazine at ∼10−6 Torr could be reduced to the metallic state at room temperature. Reduction kinetics, continuously measured at the surface using in situ x-ray photoelectron…
SUMMARY A Mg‐base Laves phase was investigated by high resolution electron microscopy (HREM). Linear defects found at terminations of stacking faults were classified into three groups. The first is a partial dislocation at a termination of a stacking fault, the second is a superposed partial dislocation which is defin…
The crystal structure of piperazinium hexadichlorocuprate (PHCC) has been determined. In this compound, the Cu(II) ions are arranged in zig-zag chains well separated from each other. As temperature is decreased from the ambient temperature, the magnetic susceptibility exhibits a maximum at T=15 K and then tends to zer…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOn the hydrogen peroxide/sulfuric acid oxidation of mesoporphyrin. Synthesis of mesoporphyrindionesC. K. Chang and Weishih WuCite this: J. Org. Chem. 1986, 51, 11, 2134–2137Publication Date (Print):May 1, 1986Publication History Published online1 May 2002Published inissue 1…
Methyl acetyl phosphate is a competitive inhibitor of the reduction of acetoacetate by D-3-hydroxybutyrate dehydrogenase. The material also irreversibly inactivates the enzyme. The kinetics of the inactivation are consistent with methyl acetyl phosphate acetylating the conjugate base of a hydrogen bond donor. Protecti…
Abstract The pentagonal column (PC), consisting of MX 7 bipyramids sharing their equatorial edges with five MX 6 octahedra, is a structural feature frequently occurring in association with frameworks of the ReO 3 ‐type, where it enables accomodation of an anion deficiency. The present article discusses the geometry of…
The mechanisms by which porphyrins form metal complexes in nature are of interest because of the importance of both the iron complexes, the active sites of hemoproteins, and the magnesium complexes, the chlorophylls. Currently there is interest in using chelated radioactive metal isotopes as diagnostic imaging and the…
The coexistence of spin-density waves and superconductivity has been theoretically analyzed in a two-band model, a case for which the commonly used descriptions for the ternary rare-earth compounds and highly anisotropic organic solids are unapplicable. The phase diagram at T=0, the temperature dependence of the order…
Metal–ligand association constants of 1:1 binary (ML) and 1:1:1 ternary (MAL) complexes of the type [Formula: see text] (where M = La 3+ , Ce 3+ , Pr 3+ , Nd 3+ , or Sm 3+ ; A = primary ligand = EDTA; L = secondary ligand = O—O, O—N, O—S donor aliphatic or aromatic ligand) have been determined potentiometrically by th…
The actual atomic concentration of Mg segregated to the basal plane of MgO‐doped single‐crystal alumina surfaces is calculated using an Auger electron spectroscopy quantification method which takes the backscattering factors and Auger electron escape depth into account. The results suggest that Mg segregates as effect…
Abstract Unique empirical relations are found to exist between the extension ratio at break λ b and the crosslink density ν λ b ∝ ν −0.75 in the absence of gross strain induced crystallization, and λ b ∝ ν −0.2 in the presence of gross strain-induced crystallization. With black-filled elastomers, the modulus at 100% s…
A model is presented that examines the mixing of ceramic powders with preceramic polymer binders that are converted to ceramic material on pyrolysis. Such polymer/powder systems, which have applications in the compaction of both SiC and Si 3 N 4 powders, can be effective in increasing the green density of die‐pressed…
A new bromide spinel has been found in the system. The orthorhombic cell dimensions are , , and at room temperature. The electrical conductivities of the new bromide spinel and the related spinel have been measured. and have been found to have high ionic conductivities of and at 400°C, respectively. High temperature x…