Materials Literature
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An electron microscope study has been made of metastable β-brass containing 61.0% copper, 39.0% zinc. It was observed that during electrolytic polishing of 0.005 in. thick foil the very thin regions of β at the edges of the foil transformed spontaneously to a face-centred cubic structure α”. This transformation is sim…
Abstract In order to verify precisely the applicability and reasonableness of the time–humidity superposition method to hydrophilic crystalline polymers, stress relaxation measurements were carried out with films of polyvinyl alcohol and nylon 6 by means of a table model Instron Tensile Tester equipped with a special…
Abstract The thermolytic decomposition of crystalline and amorphous poly( tert ‐butyl acrylate) was investigated. At elevated temperatures thin films of polymer were found to evolve isobutylene quantitatively. The weight loss curve has been analyzed, and a mechanism has been suggested involving a slow random decomposi…
The theoretical models of Callaway and Klemens are compared to experimental results in (a) silicon and diamond, (b) solidified argon and neon, and (c) KCl and NaF, which are taken from the literature. Three sources of scattering are postulated: phonon-phonon processes, isotopic point defect scattering, and boundary sc…
The absorption and fluorescence spectra of 1% and 10% Pr3+ in LaBr3 were observed and an analysis carried out. The energy levels of these Pr3+ ions are very similar to Pr3+ in LaCl3, except that the centers of the J levels differ on the order of 102 cm−1. This corresponds to a change in Slater integrals of 0.5%. This…
Excluded volume theory of nonionic high-polymer solutions has been extended to mixed polyelectrolyte-added simple electrolyte systems. A systematic study has been undertaken of fractionated polyvinylsulfonate alkali halide systems. ``Ideal'' Θ temperatures, determined from phase separation experiments and from the van…
The behavior of a symmetrical nonabsorbing multilayer in the region where the component film thicknesses are small compared with the wavelength closely approximates the behavior of a homogeneous single film. The index of the equivalent film can be made to take any value intermediate to the index values of the constitu…
Abstract An investigation of the thermal decomposition of natural cellulose is described, in which the rate of the reaction was determined by the rate of evolution of gas in vacuo in the temperature range 100–250°C. Two states of the material could be distinguished with respect to thermal decomposition behavior, the “…
Abstract The postulate of geometric equivalence of the monomeric units of a tactic chain with regard to an axis (I) and the postulate that the conformation is such that the internal energy of the chain, considered as not subjected to external forces, is the lowest (II), can be applied to the prediction of the conforma…
Abstract The specific heats of isotactic and atactic polypropylene have been measured over the ranges −14 to +211°C. and −55 to +204°C., respectively. In both cases, the samples were annealed at about 140°C. and the measurements repeated, but a slight thermal degradation prevented the results from the second heating f…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCompetitive Catalytic Hydrogenation of Benzene, Toluene and the Polymethylbenzenes on PlatinumCharles P. Rader and Hilton A. SmithCite this: J. Am. Chem. Soc. 1962, 84, 8, 1443–1449Publication Date (Print):April 1, 1962Publication History Published online1 May 2002Published…
Apparatus for measuring ultrasonic wave velocities and hence elastic moduli by means of phase-comparison methods at frequencies as high as 500 Mc is described. Gated harmonic generators for providing pulse-modulated rf of accurately known carrier frequency and circuits for electrical coupling to resonant quartz-crysta…
The deoxyribonucleic acid of the T-even coliphages contains glucosylated and nonglucosylated 5-hydroxymethylcytosine in place of cytosine (l-6). In the case of deoxyribonucleic acid from phage T6, 72y0 of the 5-hydroxymethylcytosine residues are diglucosylated. In T2 deoxyribonucleic acid, 70% of the 5-hydroxymethylcy…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA New Synthesis of Mono- and PolycarbodiimidesTod W. Campbell and John J. MonagleCite this: J. Am. Chem. Soc. 1962, 84, 8, 1493Publication Date (Print):April 1, 1962Publication History Published online1 May 2002Published inissue 1 April 1962https://doi.org/10.1021/ja00867a03…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConcentrated Solutions of NaSCN in Liquid Ammonia. Solubility, Density, Vapor Pressure, Viscosity, Thermal Conductance, Heat of Solution and Heat CapacityGeorge C. Blytas and Farrington. DanielsCite this: J. Am. Chem. Soc. 1962, 84, 7, 1075–1083Publication Date (Print):April…
Electrochemical methods for predicting behavior of corrosion-resistant alloys are reviewed and analyzed on the basis of modern electrode kinetic theory. The noble metal alloy concept and other methods to increase the corrosion resistance of active-passive metals are considered in detail. The problems associated with t…
The Raman spectra of sulphuric acid, deuterosulphuric acid, chlorosulphuric acid, and methanesulphonic acid have been redetermined, and the spectrum of fluorosulphuric acid measured for the first time. The spectra of fluorosulphuric acid – sulphuric acid, chlorosulphuric acid – sulphuric acid, and fluorosulphuric acid…
Abstract Ring compounds such as trioxane, β‐propiolactone, diketene, and 3,3‐bischloromethylcycloxabutane can be polymerized only in the solid state by γ‐radiation. These ring compounds polymerize by a ring‐opening, ionic mechanism to highly crystalline, high molecular weight, linear polymers. In general, the conversi…
Optical properties of two-layer antireflection systems are discussed. Theory is applied to study the optical performance of bismuth-oxide/magnesium-fluoride bilayers. The theoretical study includes graphs and numerical tables showing the spectral reflectances for different glass substrates, the effect of film-thicknes…
The observed stability relations of enstatite, protoenstatite, and clinoenstatite were in good agreement with the findings of earlier workers. Polycrystalline preparations of MgSiO 3 polymorphs were synthesized with the aid of small additions of MgF 2 or LiF as mineralizers. At 1042°± 3°C, enstatite, the stable low‐te…