Materials Literature
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Dilatometric and viscometric data on fractionated polystyrenes containing diethylbenzene end groups are presented over wide temperature ranges. The second-order transition temperature, viscosity-temperature coefficient, and specific volume all change rapidly with increasing molecular weight toward asymptotic limits wh…
Abstract In the first part of this paper, simple approximate methods have been developed for evaluating the electrical conductivity of films and wires of a size comparable with the mean free path of the conduction electrons. In the second part, a rigorous theory has been given of the electrical conductivity of a thin…
Evidence is presented for three new, light neptunium isotopes formed by deuteron bombardments of ${\mathrm{U}}^{233}$, ${\mathrm{U}}^{235}$, and ${\mathrm{U}}^{238}$. The isotope ${\mathrm{Np}}^{231}$ has a half-life of 50\ifmmode\pm\else\textpm\fi{}3 min. and emits alpha-particles of 6.28-Mev energy; the proportion o…
When a crystal of magnetite has been cooled through the low temperature transition (near -164\ifmmode^\circ\else\textdegree\fi{}C) in a demagnetized state, the magnetization undergoes a large and abrupt increase in the three principal crystallographic directions [100], [110], and [111] upon warming. The behavior of th…
The microwave resonance absorption technique, at both 1.25 and 3.3 cm wave-lengths, was used to study the ferromagnetic crystalline anisotropy characteristics and $g$-factor of magnetite ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$. The experiments were performed on single crystals, both synthetic and natural, from room temp…
An objective method for determining fiber irregularities is suggested wherein it is recog nized that there are many instances of crimpiness which cannot be defined in terms of frequency and amplitude measurements. An attempt was made to arrive at a simple correlation between roving diameters and single-fiber propertie…
Published differential thermal‐analysis curves for aragonite have not shown the transition to calcite near 450 °C. This inversion is clearly seen in curves presented for six samples of aragonite, and the transition is confirmed by X‐ray diffraction patterns.
The volatility of plutonium dioxide has been measured in the temperature range 1320°C to 1790°C by a modification of the Knudsen effusion method. The plutonium dioxide was heated in vacuum in a tantalum oven. Under these conditions the dioxide was reduced to a lower oxide, or oxides, which maintained a constant reprod…
(1950). 9—THE RELATION BETWEEN FIBRE AND YARN FLEXURAL RIGIDITY IN CONTINUOUS FILAMENT VISCOSE YARNS. Journal of the Textile Institute Transactions: Vol. 41, No. 4, pp. T159-T172.
A method is described by which the surface tension of surfaces occurring in the systems copper-hydrogen or argon and copper-lead-hydrogen or argon is determined. At temperatures round 850° C the surface tension between copper grains is 640 dyne/cm. and between copper and the equilibrium lead-copper liquid phase 340 dy…
The temperature dependence of F-absorption bands has been theoretically studied. It has been concluded that the main cause of the shift of the absorption peak is the thermal expansion of the lattice. As to the half-breadth of the band we calculated its temperature dependence by using the Einstein's model of lattice vi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheory, Scope, and Methods of RecrystallizationR. S. TipsonCite this: Anal. Chem. 1950, 22, 5, 628–636Publication Date (Print):May 1, 1950Publication History Published online1 May 2002Published inissue 1 May 1950https://pubs.acs.org/doi/10.1021/ac60041a002https://doi.org/10.…
The importance of crimp in natural wools is discussed. Wear and coverage of crimped vs. uncrimped materials are demonstrated. A method of crimping wool artificially is shown and production equipment is discussed schematically. Theoretical expressions are developed for stress-concentration effects and are compared with…
Vapor pressure measurements have been made with three halides of plutonium by a modification of the Knudsen effusion method. Measurements with solid plutonium trifluoride from 1200°K to 1440°K give the vapor pressure-temperature relation log10pmm=12.468–21,120/T. Measurements with liquid plutonium trifluoride from 144…
X recent years several writers have dealt with variational principles for the computation of phase shifts' and trans- mission cross sections. ' It seems worth noticing that the same approach is useful for calculating the refIection coefficient of a potential harrier.
In connection with the study of the internal friction peak (versus temperature) associated with the viscous behavior of grain boundaries in metals, some other effects were observed at higher temperatures causing an additional internal friction in superposition with the high temperature branch of this internal friction…
ADVERTISEMENT RETURN TO ISSUEPREVBook and Media Revie...Book and Media ReviewNEXTLuminescent materialsJames H. Schulman Cite this: J. Chem. Educ. 1950, 27, 5, 292Publication Date (Print):May 1, 1950Publication History Received3 August 2009Published online1 May 1950Published inissue 1 May 1950https://doi.org/10.1021/ed…
An investigation has been made of the variation of the nuclear resonance absorption line width with temperature for four long chain aliphatic compounds and eight aromatic hydrocarbons. The aliphatic compounds are dimorphous; in the lower temperature modification it is concluded that the molecules are rigid at the lowe…
Very small recrystallized grains of a large variety of orientations were produced locally in lightly rolled high purity aluminum crystals. The rate of growth of these small grains varied greatly, depending on their relative orientation with respect to the matrix crystal. Grains with an orientation corresponding to a […
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