Materials Literature
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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…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructures of Some Germanides of Formula M5Ge3Hans Nowotny, Alan W. Searcy, and J. E. OrrCite this: J. Phys. Chem. 1956, 60, 5, 677–678Publication Date (Print):May 1, 1956Publication History Published online1 May 2002Published inissue 1 May 1956https://doi.org/10.1021/j15053…
Abstract Polyethylene may be characterized by use of the light scattering technique applied to the solid polymer. The treatment of Debye and Bueche allows one to assign numerical values to this characterization in the form of two parameters, 〈η 2 〉, the mean square dielectric constant deviation and a size parameter, α…
Magnetic anisotropy induced by magnetic annealing was measured for Ni 3 Fe single crystal by means of a high temperature-torque magnetometer. It was found that the magnitude of anisotropy depends upon the crystallographic direction of the field which is applied during annealing. It was largest for <111>, next for <110…
Numerical methods are used to study the behavior of the energy levels of a nucleus, having nonzero quadrupole moment and spin I = 1 or 32, under the influence of a constant uniform external magnetic field and an electric crystalline field of axial symmetry. These numerical results are of use when experimental conditio…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Heats of Reaction of Pyridine and Nitrobenzene with Boron Trifluoride, Trichloride and Tribromide; the Relative Acceptor Properties of the Boron Halides1,2Herbert C. Brown and Robert R. HolmesCite this: J. Am. Chem. Soc. 1956, 78, 10, 2173–2176Publication Date (Print):Ma…