Materials Literature
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A group of liquid crystals, mainly derivates of cholesterol, shows remarkable optical properties, including strong rotatory power and selective reflexion of circularly polarized light in a narrow region of wave-lengths. In this paper it is shown how these properties can be explained by the assumption that the molecule…
Recently, Jonker and Van Santen have found an empirical correlation between electrical conduction and ferromagnetism in certain compounds of manganese with perovskite structure. This observed correlation is herein interpreted in terms of those principles governing the interaction of the $d$-shells of the transition me…
Abstract The theory of a previous paper is applied to the paramagnetic resonance of certain cobalt salts. The splitting of the orbital levels by the crystalline field is first investigated, and then the further splitting by the spin-orbit interaction. The g-values so derived are in good agreement with experiment. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRecent X-Ray Diffraction Studies on the Hydrous Oxides and Hydroxides.W. O. MilliganCite this: J. Phys. Chem. 1951, 55, 4, 497–507Publication Date (Print):April 1, 1951Publication History Published online1 May 2002Published inissue 1 April 1951https://pubs.acs.org/doi/10.102…
The structural reversals in cotton fibers are a preferred location of break when the fiber is ruptured in tension. With the aid of a polarizing microscope, observations were made of the fraction of fibers breaking at the reversals under various conditions of moisture content, specimen length, and chemical treatment. I…
AN IDEAL resistor would possess a resistance precisely adjusted to value and constant with time, temperature, voltage and frequency under all conditions of use in the application for which it is intended. Wirewound resistors, which early references to “resistance helices” suggest were the first to be employed, approac…
The crystallography and interfacial free energy of noncoherent twin boundaries in copper have been investigated. It is found that the noncoherent twin boundary is approximately parallel to a {113} plane of one crystal and to a {335} plane of the other. The ratio of the interfacial free energy of noncoherent twin bound…
A study has been made of the process of solidification of the alloys of tin and lead the eutectic structure of which is typically lamellar. A technique was developed in which the rate and direction of solidification were controlled. It was demonstrated that freezing takes place by the simultaneous edgewise growth of t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTON THE STRUCTURE OF ELEMENTARY BORON1J. L. Hoard, S. Geller, and R. E. HughesCite this: J. Am. Chem. Soc. 1951, 73, 4, 1892–1893Publication Date (Print):April 1, 1951Publication History Published online1 May 2002Published inissue 1 April 1951https://pubs.acs.org/doi/10.1021/…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigher Oxides of the Lanthanide Elements. Terbium Dioxide1D. M. Gruen, W. C. Koehler, and J. J. KatzCite this: J. Am. Chem. Soc. 1951, 73, 4, 1475–1479Publication Date (Print):April 1, 1951Publication History Published online1 May 2002Published inissue 1 April 1951https://pu…
By means of certain simplifying assumptions a formula is developed for the penetration into a ductile target by a high-velocity (`Munroe') jet. The action of the jet is divided into two stages, each making its contribution to the total penetration In the first stage a hole is formed by the lateral compression of the t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Heats of Formation of TiO, Ti2O3, Ti3O5 and TiO2 from Combustion Calorimetry1George L. HumphreyCite this: J. Am. Chem. Soc. 1951, 73, 4, 1587–1590Publication Date (Print):April 1, 1951Publication History Published online1 May 2002Published inissue 1 April 1951https://pub…
The diffuse intensity from single crystals of AgAu and Ag3Au was measured with crystal monochromated CuKα radiation and a Geiger counter spectrometer. Measurements were made at a series of points in the (h1h20) layer of reciprocal space. The measurements were made at both room temperature and at 160°K to allow a corre…
Improve ment of t he X -ray diffraction pattern file of t he America n Society fo r T esti ng M aterials is t he bas is for work being don e at t he N ational Bureau of Standards wi t h t he cooperat ion of t he Joint Co mmi ttee on Che mical Analysis by X -ray Diffraction Methods of t he Ameri can Society for T est i…
A theoretical and experimental study of the physical behavior of freely falling waterdrops is carried out. The influence of ventilation and environment upon the evaporation and equilibrium temperature is formulated in quantitative terms. The theoretical approach emphasizes the vapor and heat transferred to packets of…
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
The pH response, hygroscopicity, and che mi cal durability of a seri es of Na, O-K, O-Si02 glasses have bee n in vestiga ted. The pH responses of electrodes prepared from t hese glasses are in accord wit h similar dat a previously reported for t wo other series of glasses, namely, N a, O-CaO-Si02 and N a20 -PbO-Si02,…
Abstract Methods which have proved useful in the chemical and infra‐red examination of plasticizers used in polyvinyl chloride (PVC) compositions are summarized. Information is given about the method of isolation of the plasticizer and the qualitative tests which may be applied. On the quantitative side attention is g…
(1951). THE ANALYSIS OF YARN IRREGULARITY. Journal of the Textile Institute Proceedings: Vol. 42, No. 3, pp. P107-P113.
Compositions having negative linear thermal expansions ranging from 0 to –0.38% have been obtained in two areas of the system lithia‐alumina‐silica. Petrographic and X‐ray examinations indicate the presence of three principal crystalline phases, each of which is a solid solution: β ‐eucryptite, β ‐spodumene, and an un…