Materials Literature
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In this review a qualitative description is given of the various types of exchange interactions which might be present in metals and insulators and which might lead to co-operative interactions - particularly ferromagnetism. The theory of spin waves is then described and this is extended to include non-linear and temp…
Upon heating black oxygen‐deficient zirconia in oxygen of atmospheric pressure to 450° to 900°C, oxygen is taken up. The increase in the thickness of a white layer of virtually ideal composition with time follows a parabolic rate law, . The rate constant is about two orders of magnitude higher than Tammann's rate cons…
A theoretical and experimental investigation of inhomogeneous CeO(2)-MgF(2) and ZnS-Na(3)AIF(6) anti-reflection coatings for the visible spectrai region has been made. By a proper choice of the refractive index profile, the reflectance may be considerably reduced. In the infrared region, Ge-MgF(2) films on Ge substrat…
The absorption and permeation of electrolytically generated hydrogen through thin platinum foils have been observed directly by an electrochemical method. The diffusion coefficient and the associated apparent energy of activation were determined. The concentration of absorbed hydrogen was obtained, and it was shown th…
A study has been made of the preparation and properties of aluminum oxide films prepared by reactive sputtering. Deposition temperature, rate, oxygen pressure, etching characteristics in , and phase changes of the deposited films as a function of heat‐treatment were investigated. Two phases of deposited alumina could…
On compare les propriétés magnétiques (aimantations, points de Curie et susceptibilités) et les résistivités résiduelles de borures de formules générales M1-xM'xB et (M1-xM'x) 2B où M et M' désignent des métaux de la première série de transition, à celles des alliages métalliques M1-xM'x. Cette comparaison fait ressor…
Silicon nitride has very attractive electrical, physical, and chemical properties which are of great interest for microelectronic devices. Until recently, most methods that have been reported in literature produce silicon nitride in the form of powder, needles, ribbons, or flakes. Recently, Sterling and Swann reported…
Abstract The dislocation distribution in the surface layer of cyclically deformed specimens of polycrystalline copper is studied by means of transmission electron microscopy of thin foils, both parallel and nonparallel to the surface. The distribution within the surface layer and near the persistent slip bands is foun…
Abstract A polyamide amino acid was prepared by the solution condensation of 3,3′‐diaminobenzidine and pyromellitic dianhydride. This polymer was cast as a film and converted to a polybenzoylenebenzimidazole. The gross conversion path was elucidated by spectroscopy and was substantiated by model compound studies. A no…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLewis Basicity of Metals. II. The Interaction of Group VI and VII Transition Metal Cyclopentadienyl Derivatives with BF3, BCl3, and B2H6M. P. Johnson and D. F. ShriverCite this: J. Am. Chem. Soc. 1966, 88, 2, 301–304Publication Date (Print):January 1, 1966Publication History…
Infra-red studies of NH3, HCl, CO, C2H4, and butene adsorbed on transparent aerogels were made to elucidate the surface chemistry of nickel/silica and the nature of adsorbed species. In addition to the hydroxyl band found on silica at 3750 cm–1, most “dry” nickel/silica aerogels exhibited a band near 3620 cm–1, appare…
In recent years the rapid advances in the understanding of the nature of chemical bonds and in the application of quantum mechanics to chemical problems have imparted a great impetus to studies of luminescent materials, studies which have been primarily directed toward the elucidation of the electronic structures of t…
Abstract Two kinds of dielectric absorptions due to motion of carbonate groups in polycarbonate were observed. In the primary transition region near 150°C, the shape of e′ versus log frequency curve is little affected by a temperature change, while it becomes more widely spread when the polymer is partially crystalliz…
Abstract A brief review of the different topographic methods is given in order to attempt a classification of the various types of contrast observed. Depending on whether the image is obtained by a reflection or transmission method, is simple or integrated, dynamic, direct, or intermediary, the contrast and image widt…
Aided by a Post Doctoral Fellowship in Brain Research from the United Cerebral Palsy Research and Educational Foundation. Medical Investigator, Howard Hughes Institute.
The work to be described in this paper, is a study of chemical reaction between iron surfaces and various representative extreme pressure (EP) agents, such as chlorine type, sulfur type, Zn-dithiophosphate type, and the mixture of sulfur and chlorine type EP agents, by using the hot wire method. It has been observed t…
Abstract When heated to high temperatures under zero tension, some of the molecules in oriented nylon 66 filters change from the elongated to the folded conformation, with no change in crystal orientation. This transformation is shown by a combination of structural and physical property measurements: wide and small an…
Abstract Durch Aufdampfen auf atomar ebenes und reines Cu(111) wurden sehr dünne, flächenhafte Ni(111)‐Epitaxieschichten hergestellt. Der Atomabstand von Ni in der Schichtebene gleicht sich dabei oberhalb 10 Å partiell, unterhalb 10 Å bei einer Dehnung von 2,5% vollständig an den der Cu‐Unterlage an („Pseudomorphie”︁)…
Abstract An attempt was made to evaluate the apparent elastic constant of a two‐phase system G from those of the components of the system. The modulus G is expressed as follows: where G 1 and G 2 are the shear moduli of the suspending medium and the suspended particles, respectively, v 1 is the Poisson ratio of the me…
A model for F-centre production in alkali halides by ionizing radiation is discussed. The energy required for the formation of the defect is given to an anion in the radiationless recombination of an electron and a hole, which takes place via an exciton state. The primary products of this mechanism are negative ion in…