Materials Literature
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All articles of this category Addition of donor ligands such as pyridine N -oxide or 2-methylimidazole to the chiral (salen)manganese(III) complex catalyzed asymmetric epoxidation of unfunctionalized olefins was found to be effective for altering the enantioselectivity and the chemical yield. The highest asymmetric yi…
Solutions of Keggin-structure polyoxometalates have been studied by IR, Raman and UV spectroscopies, with various solvents and counterions. For the tetraalkylammonium compounds, cation–anion aggregates are observed. This model of cation–anion aggregates can be applied to the solutions of the acids in DMF and DMSO. The…
An Al70Ni15Co15 alloy, known to form a stable decagonal quasicrystal, was subjected to various heat treatments and studied with electron diffraction and high-resolution electron microscopy. The alloy quenched from 800°C forms a decagonal quasicrystal, which shows diffraction patterns with a large number of sharp spots…
The results of a study on the suppression of leakage current on room temperature vulcanizing (RTV) silicone rubber coated porcelain suspension insulators in a salt-fog chamber are reported. A comparative study of the performance of coatings on different parts of suspension insulators with RTV is reported. The results…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemistry and electrochromic behavior of Langmuir-Blodgett films of octakis-substituted rare-earth metal diphthalocyaninesYunqi Liu, Kiyotaka Shigehara, Masahiko Hara, and Akira YamadaCite this: J. Am. Chem. Soc. 1991, 113, 2, 440–443Publication Date (Print):January 1…
Abstract Natural (untreated) clays are most probably amorphous on their outermost surface layers due to the continuous and natural process of partial dissolution and reprecipitation of the clay components at the solid‐aqueous interface. The pH‐dependent adsorption on Al and Si oxides, mordenite, kaolinite, and montmor…
Aggregate size and abundance were monitored in situ at a fixed station in the southern North Sea d u r ~n g a 6 wk investigation which covered the phytoplankton spring bloom and the pre-and post-bloom periods. Particle aggregates were abundant dunng the entire period of study. Biologically derived material, such a s a…
New layered perovskite compounds ${\mathrm{Sr}}_{\mathit{n}+1}$${\mathrm{V}}_{\mathit{n}}$${\mathrm{O}}_{3\mathit{n}+1}$ (n=1, 2, and 3) and ${\mathrm{SrVO}}_{3}$ (n=\ensuremath{\infty}) were synthesized, and the physical properties of the compounds with n=1, 2, and \ensuremath{\infty} were investigated. ${\mathrm{Sr}…
The synthesis of unsymmetrically or non-uniformly surface-functionalized dendritic macromolecules using a stepwise convergent-growth approach is described. By stepwise alkylation of the monomer unit, 3,5-dihydroxybenzyl alcohol, with unsubstituted and substituted benzylic bromides, followed by activation of the group…
The structure of Zn[C(CN)3]2 consists of two independent infinite rutile-related frameworks whose compiex entanglement resembles 3D knitting.
The crystallization of CaCO3 under compressed Langmuir monolayers of stearic acid [CH3(CH2)16CO2H], octadecylamine [CH3(CH2)17NH2], octadecanol [CH3(CH2)17OH] and cholesterol (C27H45OH) has been studied over a range of supersaturation conditions by optical and scanning electron microscopy and X-ray diffraction. At tot…
Molecular methods have been applied to analyze the expression of the Alcaligenes eutrophus poly(3-hydroxybutyrate) (PHB) synthase gene (phbC). The translational initiation codon was identified by analysis of the amino acid sequence of a PHB synthase-beta-galactosidase fusion protein. This protein was purified to almos…
Transmission electron microscopy and electron diffraction have been used to determine the structure, orientation and morphology of CaCO3 crystals at the early stages of growth under compressed Langmuir monolayers of stearic acid [CH3(CH2)16CO2H] and octadecylamine [CH3(CH2)17NH+3]. At [Ca]≈ 9 mmol dm–3, elongated plat…
Improved KIC values of monolithic Si3N4 ceramics will be expected by growing-in a matrix of microcrystals of β-phase Si3N4-an appreciable amount of extensively large, rod-shape crystals of the same phase. It is anticipated that the large grains should play as crack impediments like whiskers mixed in composite ceramics…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAb initio molecular orbital calculations of the internal rotational potential of biphenyl using polarized basis sets with electron correlation correctionSeiji Tsuzuki and Kazutoshi TanabeCite this: J. Phys. Chem. 1991, 95, 1, 139–144Publication Date (Print):January 1, 1991Pu…
Cyclic fatigue, and specifically fatigue-crack propagation, in ceramic materials is reviewed both for monolithic and composites systems. In particular, stress/life (S/N) and crack-propagation data are presented for a range of ceramics, including zirconia, alumina, silicon nitride, SiC-whisker-reinforced alumina and a…
On a fritte β-SiC a plus de 95% de la densite theorique entre 1850 et 1950°C avec addition de Al 2 O 3 et Y 2 O 3 . On a realise la densification en utilisant une phase liquide formee entre Al 2 O 3 , Y 2 O 3 et SiO 2 a environ 1760°C. Le liquide presente une bonne mouillabilite vis-a-vis de SiC. La ceramique obtenue…
Highly oriented multilayered films of polyaniline are fabricated by intercalative polymerization of aniline in fluorohectorite, a synthetic mica-type silicate. The insulating hybrid becomes electrically conductive when exposed to HCl vapors with an in-plane conductivity of 0.05 S cm−1. The conductivity of the multilay…
Synthetic barite crystals, prepared under conditions chosen to mimic those encountered in off-shore oil fields, have a simple rhombic plate-like morphology in which large (001) faces are bound by smaller (210) sides. The addition of certain stereochemically related diphosphonates produces a characteristic morphologica…
Techniques were developed and described for performing three-dimensional finite element analysis of plain weave composites. This paper emphasizes aspects of the analysis that are different from analysis of traditional laminated composites, such as the mesh generation and representative unit cells. The analysis was use…