Materials Literature
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Abstract The elastic modulus of highly oriented crystalline polymers is discussed in terms of a series model. As has been shown previously, if a polymer has fully extended chain configurations within the crystalline regions, the modulus of this phase may be expected to be high. In this case the macroscopic elastic mod…
Abstract It is shown that synthetic rubbers, in contrast to natural rubber, can be vulcanized to soft rubber by a simple thermal treatment without any previous admixture of sulfur or accelerators. This process has been designated as “Thermovulcanization” to distinguish it from the regular vulcanization procedure under…
Abstract Measurements are described of the rate and final extent of crystallization at a temperature of −25°C. in natural rubber which has been modified by the chemical combination of sidegroups to the rubber molecule. The substances added were six thiol acids. Their efficiencies in retarding crystallization are compa…
Past attempts to describe the d electrons of the transition metals have been based on one or the other of two extreme views: the one, the conduction-band model, treats the d electrons as though they belong to the lattice as a whole rather than to particular atoms; the other, the shell model, treats the d electrons as…
Yield point phenomena occur on retesting copper single crystals during interrupted tensile deformation. The effect is observed only during the linear and parabolic regions of the stress-strain curve and the size of the yield drop is directly proportional to the reduction in stress on unloading. The ratio of the flow s…
A crystallographic study on the mechanical twinning in Ti and α-U is made by a method similar to that in a previous paper, allowing more kinds of atom movements, and the twin elements, K 1 , K 2 , η 1 and η 2 , are determined. It is found that {11\bar22} and {11\bar24} twins in Ti are reciprocal to each other and that…
The temperature dependence of the crystalline anisotropy constants of iron, cobalt, and nickel is discussed. It is shown that Zener's result for iron (i.e., the first anisotropy constant varies as the tenth power of the magnetization) also may be derived from molecular field theory. In cobalt a satisfactory agreement…
Current ``domain'' theory relies heavily on Bloch walls and the Landau-Lifshitz method of assembling them. A rigorous attack on the same problem leads to a nonlinear boundary-value problem; with electronic computers available, this problem is now less formidable than when it was first formulated. Numerical calculation…
The small angle scattering of x-rays or neutrons from crystals containing a random network of dislocations is calculated. Three causes of density changes associated with dislocations are considered : that due to the elastic strain field from edge dislocations, that due to second-order elasticity effects and that due t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Vapor Pressures of Zirconium Tetrachloride and Hafnium TetrachlorideA. A. Palko, A. D. Ryon, and D. W. KuhnCite this: J. Phys. Chem. 1958, 62, 3, 319–322Publication Date (Print):March 1, 1958Publication History Published online1 May 2002Published inissue 1 March 1958http…
ADVERTISEMENT RETURN TO ISSUEPREVArticleThe Thermal Stability of Copper PhthalocyanineEmil A. LawtonCite this: J. Phys. Chem. 1958, 62, 3, 384Publication Date (Print):March 1, 1958Publication History Published online1 May 2002Published inissue 1 March 1958https://pubs.acs.org/doi/10.1021/j150561a051https://doi.org/10.…
The information available regarding the survival of freshwater algae during dry periods is somewhat meagre. Text-books (Fritsch 1935; Smith 1938, 1951; West & Fritsch 1927) refer to 'resting cells', 'cysts', 'akinetes' and 'resistant stages' but with some exceptions little appears to be known in detail about the droug…
8-Nylon zeigt bevorzugt eine monoklin entartete Gitterstruktur, bei der α = b und γ = 60° wird. Sie beruht darauf, daß an Stelle des bekannten Rostebenensystems ein räumliches Wasserstoffbrückensystem tritt. Dieses räumliche Netzwerk macht eine direkte höhere Orientierung unmöglich. Auch die triklinen Hochtemperaturmo…
Crystallographic and magnetic measurements of the system Li+xNi++1−2xNi+++xO for the entire range 0≤x<0.5 are reported. For values of x≤0.3, the lattice appears to be antiferromagnetic and is cubic above the Curie temperature. For the range of compositions 0.3<x<0.5, the lattice is rhombohedral an…
The system LaMn1−xNixO3+λ has been prepared under varying conditions for the entire range of compositions 0≤x≤1. The saturation magnetization, lattice parameters, and chemical analysis have been measured for each sample. The origin of discrepancies in the literature on the crystal structure of LaMnO3 is shown to be du…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymeric Phthalocyanines1C. S. Marvel and John H. RassweilerCite this: J. Am. Chem. Soc. 1958, 80, 5, 1197–1199Publication Date (Print):March 1, 1958Publication History Published online1 May 2002Published inissue 1 March 1958https://doi.org/10.1021/ja01538a045RIGHTS & PERMI…
The magnetic moments of holmium and thulium metals have been measured in applied fields of 3000-18 000 oersteds, over the temperature range of 4.2-300\ifmmode^\circ\else\textdegree\fi{}K. Holmium, paramagnetic above 133\ifmmode^\circ\else\textdegree\fi{}K, appears to be antiferromagnetic between 20\ifmmode^\circ\else\…
Summary A technique is described for the identification of clay minerals, the layers of which are difficult to expand or collapse by the usual treatment with glycerol and KCl. Samples are extracted for 3 to 6 hours in normal sodium citrate at pH 7–3 and 100° C. The citrate is renewed hourly. After the citrate extracti…
Abstract Electron micrographs of highly crystalline PTFE crystallized by slow cooling from temperatures not far above the melting point show well‐marked bands, often with striations perpendicular to the bands; optical evidence shows that the chain molecules are parallel to the striations. The structure is in marked co…
Thin magnetic films (∼1000 A) evaporated onto a heated glass substrate in the presence of a dc magnetic field develop a uniaxial magnetic anisotropy energy of the form Ek=Ksin2φ, with φ measured from the deposition field. Such films promise to outperform ferrite cores in digital-computer memory-systems by several orde…