Materials Literature
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Stator windings in large alternators commonly use Roebel bars in which subconductors (strands) are transposed in the slot portion. Circulating currents may flow between the strands within a bar owing to the leakage fields in the end-winding regions. It is shown in the paper that such circulating current is not only li…
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Abstract It is argued that many magnetic phase transitions are not, according to Landau's theory, strictly second‐order phase transitions. A detailed discussion of the application of Landau's theory of second‐order phase transitions to antiferromagnetic UO 2 , MnO, FeO, CoO, and NiO is given in terms of Jahn‐Teller di…
PbSe thin films are prepared by chemical bath deposition technique over microscope glass substrates from an aqueous acidic bath containing lead nitrate and sodium selenate. The influence of bath temperature on the properties of PbSe film is investigated. The X-ray diffraction analysis showed the deposited films were p…
Irradiation of 2-cyanopyrrole in methanol yields 3-cyanopyrrole as a major photo-product; this is believed to be the first example of the 2–3 valance isomerization of pyrroles.
Abstract
Antimicrobial properties of chitosan extracted from indigenous shrimp processing waste were determined against one gram-negative (Salmonella Paratyphi) and one gram-positive bacterium (Staphylococcus aureus) in vitro. The antimicrobial activities of chitosan were explored by calculation of the Minimum Inhibitory Conce…
The structure of hexaiodobenzene has been elucidated by an X-ray study based on photographic data. The crystals are monoclinic pseudo-hexagonal, space group P21/n, which here requires the C6I6 unit to be centrosymmetric. Within experimental error the carbon skeleton is a regular planar hexagon with mean C–C distance 1…
The thermal conductivity of ThO2-UO2 and ThO2-CeO2 systems were measured by laser flash method, and the results are discussed with the aid of the relaxation-time theory. Two parameters characteristic to systems of the same base — the ratio α of scattering rates between N- and U-scatterings and the strain parameter ϵ—…
The thermal expansion coefficient α was measured over the temperature range from 800°C to room temperature for Fe-Ni (fcc) alloys. The results obtained are as follows: (1) On the temperature vs. α curve, a peak appears at the Curie temperature Tc of the alloys in the composition range above about 42%Ni but disappears…
The d–d spectra of tetragonal copper(II)–oxygen systems are discussed. The position of the transition dz2→dx2–y2 in eight compounds can be accounted for in terms of σ-bonding and electrostatic effects. The other two transitions are less readily treated since they are affected by π-bonding. However, the d orbital split…
カーボンブラック系加硫ゴムについて, パルスNMR法によりカーボンブラック周辺に形成される稠密構造 (C相), およびカーボンブラック周辺から離れた部分 (A相) のゴム分子鎖達の分子運動性とその成分量を解析し, 分子運動性の状態から見た構造を, 純ゴム, プラスチックと比較すると同時に, 力学的刺激による構造 (状態) 変化と, それに関する過去の実験結果を整理し、次のような結果を得た.1. カーボンブラック系加硫ゴムは準ガラス状態の相 (C相) と液体の相 (A相) とよりなり, 前者はNMR半値幅で約5gaussで, その相のゴム分子鎖達の運動は非運動性であり, 層の厚さは充てん剤の補強性により異なるが, ISAF級で約45…
Transition-metal ion complexes with the ligands p-nitrosoaniline and N-methyl-p-nitrosoaniline have been prepared and studied. I.r. spectra, solution and mull visible spectra, magnetic moments, and molar conductances are reported. I.r. and n.m.r. evidence is presented for the presence of an equilibrium mixture of nitr…
Oxygen‐18 enriched oxygen and carbon dioxide‐carbon monoxide atmospheres have been used in the determination of the oxygen self‐diffusion coefficient in monoclinic zirconia at 990 °C. Oxygen exchange measurements were made on zirconia spheres in the average size ranges of 90 and 126µ. The diffusion coefficient was fou…
High‐temperature x‐ray and DTA investigations of the lead oxide‐lead sulfate system confirmed the phase relations established by Esdayle and Lander. In order to elucidate discrepancies in the literature and to insure positive identification of the three basic lead sulfates , , and , single crystals were prepared and i…
Abstract These studies were undertaken to determine the thermal behavior of structurally related polymers having a carborane nucleus in the recurring unit. Three of these products also contained phthalocyanine rings in their molecules. Results of thermal analysis studies show generally that the relative heat stability…
The efficiency of TiO2 as a nucleating agent in the Li2O—Al2O3—SiO2 system is explored over a wide composition range. Sharp changes in crystal growth rate, which strongly influence nucleation rate, are observed near the Li2O·Al2O3—SiO2 composition line and are ascribed to changes in fluidity of the glass at the crysta…
The initial phase of the reaction between powder and liquid has been investigated. Electrophilic attack by protons in the liquid results in the decomposition of the powdered glass with liberation of cations and fluoride ions. The extent of the attack depends on the degree of acidity of the liquid.
Methyl fluorosulphonate N-methylates octaethylporphyrin and octaethylchlorin to give, depending upon the reaction conditions, N-methyloctaethylporphyrin, two NN′-dimethylporphins, NN′N″-trimethylocataethylporphin, and an N-methyloctaethylchlorin.
Titanium alkoxides react readily and reversibly with isocyanates by insertion into the Ti–O bond to form mono-, di-, tri-, or tetra-N-titano-urethanes. With titanium aryloxides the reaction is much slower and irreversible. Carbodiimides react in a similar manner to give only the di-substituted-N-titanoisoureas. The re…