Materials Literature
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A new mathematical model of hysteresis, based upon the previous work of Chun and Stromsmoe, is introduced. The model not only provides for hysteresis loops at frequencies down to dc but allows for extensive control over higher frequency behavior. Loop widening with increased frequency can be included, as well as loop…
To account for the observed diffraction pattern of a commercial specimen of oriented fibers of isotactic polypropylene in the a modification, the crystal structure is described as belonging to the space group P 21/c but having a certain disorder in the distribution of “up” and “down” chain direction. As a result of th…
The influence of the catalyst support on the oxidation of methane over palladium has been studied using a microcalorimetric bead reactor. The nature of the support had no detectable influence on the catalytic activity during a given experiment, but was found to affect the long-term stability of the catalyst.Investigat…
The effects, on the performance of all-dielectric interference filters, of errors in the turning value method of film-thickness monitoring, are studied theoretically by both an accurate and an approximate method. It is shown that, although the potential accuracy of the method in monitoring a single layer is very poor,…
A scanning reference electrode has been used to measure the number of active pits on 304 stainless steels in ferric chloride solution with time. The probability of a pit deactivating has been discussed in terms of the physical and chemical properties of solid oxide films over the pit which were originally on the steel…
A theory of the cooperative Jahn-Teller effect is developed for the purpose of discussing the spontaneous crystal distortions in mixed chromites, Cu 1- x Ni x Cr 2 O 4 and Fe 1- x Ni x Cr 2 O 4 . The static Jahn-Teller effect only is taken into account. The theory separates the self-energy of each ion having a degener…
The kinetics of active iron dissolution at 25°C has been studied in deaerated 1 N and 6 N chloride solutions for hydrogen ion concentrations of 0.1–6.0 N . For 1 N chloride solutions with , the dissolution reaction is described by anodic Tafel slope and electrochemical reaction order with respect to hydrogen ion activ…
Anodic dissolution of n + ‐, n‐, and n − ‐type silicon in 5% aqueous hydrofluoric acid at moderate current densities results in the formation of etch channels which propagate in crystal‐oriented directions in the monocrystal. Density and depth of the channels are a function of the applied voltage, the donor concentrat…
T. W. Thomas and A. E. Underhill, Chem. Soc. Rev., 1972, 1, 99 DOI: 10.1039/CS9720100099
Observations on schlieren textures of nematic and smectic-C liquid crystals in thin layers are reported. The theory of schlieren textures is discussed and forces between singularities are considered. A singularity can be characterized by a positive or negative number which is proportional to the number of brushes it s…
Thiogallate compounds represented by the formula MGa 2 S 4 [ where M = Ca + 2 , Sr + 2 , Ba + 2 , Pb + 2 , Eu + 2 , ( Na + 1 La + 3 ) and ( Na + 1 Ce + 3 ) ] were prepared by solid‐state reaction. Single crystals of the alkaline earth derivatives were also obtained by vapor transport of the corresponding polycrystalli…
The heat capacity of o-terphenyl has been measured with an adiabatic calorimeter for the crystal from 2°K to Tm (329.35°K), for the glasses from 2°K to Tg (around 240°K) and for the liquid from Tg to 360°K, on a sample with less than 0.005 mole % impurity. The heat of fusion and the entropy of fusion are 17 191 J mole…
A simple theory of the swelling of materials subjected to high energy particle irradiation is developed. Chemical reaction rate equations are used as a basis. Point defects, interstitials and vacancies, are assumed to be produced randomly throughout the solid. They move by random walk through the material until they c…
Abstract not Available.
A comprehensive study of the magnetic properties of nonstoichiometric (cation-deficient) titanomagnetites is described. Measurement of the saturation magnetization of synthetic samples provides information about the mechanism by which increasingly nonstoichiometric states evolve. It is concluded that in the spinel str…
The Maier-Saupe theory of the nematic mesophase is extended to rod-like molecules interacting with a perfectly general anisotropic potential. The resulting series expansion for the pseudo-potential accounts quantitatively for the observed temperature dependence of the orientational order, even when the expansion is re…
Current physicochemical knowledge on the structure of collagen is based almost exclusively on dilute solution measurements or on results from x-ray diffraction studies and electron microscopy of native and reconstituted collagen fibers and fibrils. A comprehensive treatise of this subject has recently appeared [1]; th…
During pitting of iron and stainless steels the potential drop across the interface of the dissolving surface within the pit is in the region of active metal dissolution, even when the potential of the specimen surface is controlled at potentials as high at +1.4 (SHE), as well as during natural corrosion. This conclus…
Abstract not Available.
Abstract Die wichtigste und nahezu einzigartige Eigenschaft der makrocyclischen Polyäther („Kronenverbindungen”︁) ist ihre Tendenz zur Komplexbildung mit Alkalimetallsalzen und Salzen mit ähnlichen Kationen. Derartige Komplexe werden durch nichtgerichtete Coulomb‐Kräfte zwischen dem Kation und den negativen Enden der…