Materials Literature
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The dehydration of kaolinite was carried out in a vacuum to evaluate the kinetics without the marked effect of water vapor. Samples of carefully fractionated particles were used and the effect of surface area was determined. At pressures in the order of 1μ of Hg the reaction was found to be diffusion‐controlled, with…
The electrical conductivity and relative fractions of ionic and electronic conductivity of single crystals of MgO were measured between 1000° and 1500°C. The results resolve conflicting observations of electronic and ionic conductivity of previous investigations in that MgO is shown to exhibit both kinds of conductivi…
Apparently healthy, unanesthetized dogs weighing 12.3 ± 1.8 kg were caused to pant by the warming effect of incandescent lamps. Panting frequency was recorded and found to be 5.33 ± 0.7 cycles/sec. The natural frequency of the respiratory system of each of the animals was then determined, the mean being 5.28 ± 0.3 cyc…
Abstract A spherulitic crystallization process can be divided into three successive stages: the formation of spherulite centers, the growth by means of crystalline fibrils with many branches extending into the melt, and finally crystallization of the intervening regions between these already crystallized fibrils. The…
The present status of soft magnetic alloys used in power generation, communication, and special devices applications will be reviewed with emphasis on future prospects for their improvement. Although the study of microscopic structure of magnetic materials has led to important advances, present and future improvements…
Alumina whiskers have been grown on single-crystal alumina substrates by heating aluminum filings, located near the crystals, to 1400°C in a stream of wet hydrogen. The whiskers grew crystallographically coherent with the substrate, and had their axes either parallel to the c axis or in one of 12 equally spaced direct…
Several samples of CrSx with 1.145<x<1.200 were carefully prepared and chemically analyzed. The expected crystal structures were verified by x-ray analysis, which failed to indicate the presence of any impurities. Conductivity measurements indicated the existence of metallic conductivity in these samples…
Magnetization curves of the cubic spinels MnCr2O4, CoCr2O4, MnV2O4, and CoV2O4 have been obtained between 4.2°K and their Curie points. With the possible exception of MnV2O4, all the curves indicate the presence of a magnetic transition within this temperature range. Although all these materials have been reported to…
The experimental data are analysed with the following conclusions. The molecular decay time τ0 of a thin anthracene crystal lamina at room temperature is 10 nsec. The thick crystal values are increased by self-absorption to 31.6 nsec (volume excitation, e.g. by γ-rays), 24.1 nsec (surface excitation, e.g. by ultra-vio…
An investigation of the phase relations of the section Fe2P–Co2P in the system Fe–Co–P showed that at high temperature all (Fe, Co)2P alloys, including the final components Fe2P and Co2P, probably form a continuous range of solid solutions having the hexagonal Fe2P structure. At low temperatures Fe2P and Co2P form an…
Nickel-iron spinels with compositions between NiFe2O4 and Ni2FeO4 have been prepared under oxygen pressures up to 2000 psi and at temperatures between 250° and 1000°C. Good agreement was found between the measured lattice parameters of the resulting spinel phases and the values obtained by extrapolating from the previ…
Recent development in the theory of screw structure of spins and its modification due to anisotropy energy and applied magnetic field is reviewed, with reference to neutron diffraction work on rare-earth metals and MnAu2.
Abstract The sequestration of calcium by polyphosphates in the presence of oxalate as a precipitating agent is reported at 25 and 60C in the pH range of 5–12. Sequestration increased with temperature. The sensitivity of sequestration to pH changes decreased with increase in the chain length of the polyphosphates. Magn…
Ferromagnetic resonance has been observed in single crystals of anhydrous chromium tribromide using frequencies of 20 to 27 kMc. At 1.5°K a g value of 2.006 is found along with a uniaxial anisotropy, K=9.4×105 ergs/cm3. Linewidths as narrow as 3.5 oe have been observed at 1.5°K.
The anisotropy in the plane of the film of thin films of Ni evaporated on Mo-covered substrates and of oxidized Ni films has been measured as a function of field and temperature. At intermediate fields, 200–1200 oe, a large rotatable anisotropy is found, about an order of magnitude larger than the usual magnetic annea…
Abstract The effect of polymer density on the gas permeability of polyethylene film has been studied. The experimental data for permeability P are described by the equation P = K (1 — d ) n , where K is a constant characteristic of each gas and d is the sample density. This equation is similar to previous analytical d…
The oxygen parameter of CrO2, which has the rutile structure, has been determined to be u=0.301±0.004. Single-crystal measurements of cell constants over the temperature range −200° to +200°C show the unusual decrease in the c axis with increasing temperature in agreement with x-ray powder results reported by other wo…
Neutron diffraction has been performed on powder specimens of Mn2As and Mn2Sb0.7As0.3. Mn2As has the antiferromagnetic structure found in Mn1.9Cr0.1Sb below the exchange inversion temperature. The atomic moments are 3.7 and 3.5 Bohr magnetons for Mn(I) and Mn(II), respectively. The moments lie perpendicular to the tet…
Abstract The postdepositional transformation of montmorillonite and/or mixed-layer illite-montmorillonite to illite is suggested as a source of silica cement in some sedimentary rocks. Depth of burial appears to be an important factor in effecting this change, and although supporting data are lacking, the changes in m…
99.999% copper crystals were deformed in tension using an Instron tensile tester, and the dislocation density and arrangement in the crystals were determined before, during, and after the deformations using an etch pit technique. For crystals of low initial dislocation density, it was found that a large amount of disl…