Materials Literature
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By measurement of the specific heat, temperature coefficient of expansion, Young's modulus and yield point in Cu3Au alloys, it has been established that this alloy undergoes a phase transition between 550° and 600°C and possibly another one near 850°C. The temperature of the 550–600°C transition decreases sharply as t…
Gadolinium orthoferrite, GdFeO3, in single-crystal form exhibits magnetization between temperatures of 78 and 295°K which consists of a field independent part σ0 and a field dependent part χH for fields above 6000 oersteds. The parasitic ferromagnetization σ0 amounts to about 1% of the σ(Fe) available and may be attri…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNotes - Basic Zinc Double Salts of O,O-Diakyl Phosphorodithioic AcidsV. Wystrach, E. Hook, and G. L. ChristpoherCite this: J. Org. Chem. 1956, 21, 6, 705–707Publication Date (Print):June 1, 1956Publication History Published online4 March 2003Published inissue 1 June 1956http…
Phase equilibrium data, obtained by using the quenching technique, are presented for the system iron oxide‐A1 2 O 3 in air and at 1 atm. O 2 pressure in the temperature interval 1085° to 1725°C. Stability ranges of the various phases are delineated, and approximate compositions of crystalline and liquid phases are det…
Magnetic susceptibility measurements by the Faraday method have been made in the temperature range 4-550\ifmmode^\circ\else\textdegree\fi{}K for a series of iron-free nickelous oxide samples prepared by the heat-treatment of hydrous nickelous hydroxide in a current of nitrogen at temperatures of 250-1300\ifmmode^\circ…
Colloidal silica of 30, 20, 10, and 5% concentrations by weight have been used to produce small-angle scattering. The resulting scattering showed plateaus which varied in angular position with concentration in the very small angle portion and then showed an approximation to the single particle scattering in the larger…
Summary X-ray diffraction data on serpentine minerals are discussed. There arc three structural varieties of chrysotile: ortho-chrysotile, clino-chrysotile, and para-chrysotile. Methods are described for the estimation of the proportions of the first two of these in mixed specimens, and their distribution in nature is…
It is a feature of many atomic diffusion jump mechanisms that successive jumps of an atom are “correlated” in the sense that the direction of a jump is not completely at random but is influenced to some extent by the direction of the preceding jump or jumps. General formulae are derived for the diffusion coefficient w…
Robert L. Ehrmann, George O. Gey; The Growth of Cells on a Transparent Gel of Reconstituted Rat-Tail Collagen2, JNCI: Journal of the National Cancer Instit
The crystal structure of gadolinium orthoferrite, GdFeO3, has been determined from single-crystal x-ray data. There are four GdFeO3 distorted perovskite units in the orthorhombic cell with lattice constants a=5.346, b=5.616, c=7.668, all ±0.004 A. The structure is solved on the basis that the most probable space group…
Pyroelectric currents produced by light flashes have been observed and measured in single crystals of guanidine aluminum sulfate hexahydrate from room temperature down to -180\ifmmode^\circ\else\textdegree\fi{}C. At room temperature the currents are about one-tenth of those produced in equivalent barium titanate cryst…
A semiempirical analysis of the superexchange interactions responsible for the formation of the magnetic lattices in ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ and $\ensuremath{\alpha}$-${\mathrm{Fe}}_{2}$${\mathrm{O}}_{3}$ is given. The difference between the two magnetic lattices is attributed to the fact that ${\mathrm{…
The isothermal $M\ensuremath{-}H$ curves of magnetite in the principal crystallographic directions have been measured from room temperature to the Curie point. These curves give the anisotropy energy and spontaneous magnetization as a function of temperature. Near the Curie point the magnetizing field required to crea…
A ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ single crystal was grown by the flame fusion method. It has rhombohedral symmetry and showed an antiferromagnetic Curie temperature (${T}_{c}$) of 307\ifmmode^\circ\else\textdegree\fi{}K. Below ${T}_{c}$ the magnetic susceptibility $\ensuremath{\chi}$ perpendicular to the [111]…
The octahedral sites in the spinel structure form one of the anomalous lattices in which it is possible to achieve essentially perfect short-range order while maintaining a finite entropy. In such a lattice nearest-neighbor forces alone can never lead to long-range order, while calculations indicate that even the long…
Single crystals of highly pure aluminium (99.99%) were plastically deformed and examined by means of electron microscopy and electron diffraction. Surfaces of the deformed crystals produce innumerable slip lines of various slip amounts and deformation bands. The latter greatly affect the diffraction pattern; Laue spot…
A mathematical analysis of various causes of irregular pickspacing has been carried out with special reference to the effect of warp and fabric relaxation on the position of the cloth fell and pickspacing.The effect of the free length of warp and fabric and the effect of different types of let-off motion are discussed.
This investigation shows that there is a relationship between viscosity, number of nuclei, and crystal growth during the firing of titania‐opacified enamels. This agrees with a similar relationship which Tammann found in his experiments with organic glasses. The history of the development of the size, shape, and relat…
A survey of all known semiconductors suggests that it is useful to discuss the existence and properties of a specific ‘ semiconducting bond ’. A valence bond treatment of semiconductors, because it takes account of the properties of the specific atoms present, furnishes certain results which are not provided by the us…
Abstract Polyvinyl chloride was condensed with a series of aromatic compounds (benzene, toluene, m ‐xylene, pseudocumene, and mesitylene) in the presence of aluminum chloride. These condensation reactions were carried out in several reaction media, in heterogeneous or semihomogeneous systems. The catalyst concentratio…