Materials Literature
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The rigid-sphere theory of liquids is shown to yield an expression for the surface tension of a one-component liquid which is essentially identical to an expression previously derived by the author employing a qualitative approach. Such a correlation suggests that the rigid-sphere theory of liquids approach is applica…
The spectrum of the free tripositive praseodymium ion (Pr IV) has been obtained under high resolution between 1200 Å and the infrared. The analysis has yielded all 49 levels of the four lowest configurations 4f2, 4f5d, 4f6s, 4f6p. A comparison with the crystal levels of Pr3+ in various lattices shows a depression of u…
A series of strontium ferrate compositions ranging from SrFeO2.7 to SrFeO3.0 have been produced by equilibration at oxygen pressures ranging from 0.2 to 855 atm. The stoichiometric composition SrFeO3.0 exhibits a simple cubic perovskite structure (a=3.850 Å). Ceramic disks of this material are conductive (ρ≈10−3 Ω·cm)…
The M\"ossbauer effect for ${\mathrm{Fe}}^{57m}$ in the BaTi${\mathrm{O}}_{3}$ lattice has been studied from 300 to 1200\ifmmode^\circ\else\textdegree\fi{}K with particular emphasis on the region near the Curie temperature. The M\"ossbauer probe seems to serve as a useful tool for the study of ferroelectrics. The elec…
The thermal expansion of a polycrystalline (U0.30, Zr0.70)C0.97 solid solution was determined between 25° and 982°C by means of a high-temperature x-ray diffraction technique. For the range 25° to 1000°C the average linear thermal-expansion coefficient is 7.78×10−6/°C. The 25°C lattice parameter is 4.7822 Å, the calcu…
Chemical and structural information relating to the BeO-H2O system is discussed and correlated. The infrared spectra of α, β, and amorphous Be(OH)2 have been studied in the range 650 to 10,000 cm-1. These show that the constitution of the three hydroxides is similar. The spectra are interpreted to arise from the coupl…
1~he ra nge of a hi g h temperature rota Ling cylinde r v iscometer has bee n extended so t hat VISCOSIty m easuremen.ts can be m ad e betwee n 10 0 to 10 10 p oises to within 2-p ercen t a ccuracy. ThiS lllvolves three different tec hniques . After a calibration consta nt has been determined for the apparatus III the…
The subsolidus phase equilibrium diagram for the pseudobinary join MgAl 2 O 4 ‐Ga 2 O 3 was determined. The shape of the exsolution boundary was obtained by heat‐treating samples pre‐ equilibrated at 1600°C. Crystalline solubility of Ga 2 O 3 in MgAl 2 O 4 decreased from 73 mole % at 1600°C to 55 mole % at 1200°C. The…
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Measurements of lateral contraction in the plane of the sheet and of changes in thickness were made on cross-laid and random-laid bonded-nber fabrics subjected to a tensile stress either parallel or at right angles to the machine direction. From these measurements, the corresponding changes in volume were derived. The…
Friction experiments were conducted in vacuum (10(exp -9) mm Hg) with oriented single- crystal titanium rider specimens sliding on polycrystalline titanium disk specimens. Experiments were conducted at a surface speed of 2.28 centimeters per second and loads from 250 to 1000 grams. Two principal single-crystal orienta…
The diffusion-limited climb rate of a straight dislocation immersed in a nonequilibrium concentration of point defects was calculated in the quasisteady-state approximation. It was shown that this approximation should apply in many cases of interest. Full account was taken of the effect of the dislocation climb motion…
The two recognized forms of calcium sulfate hemihydrate can be identified by the position of a relatively small exothermic peak in their differential thermograms. Hemihydrates prepared at various water vapor pressures up to 760 mm Hg were found to produce this exothermic peak in a position which is characteristic for…
Expressions are derived which express Young's modulus of an anisotropic aggregate of hexagonal crystallites in terms of the single-crystal elastic constants and functions of the preferred orientation, assuming either a constant tensile strain or a constant tensile stress throughout the aggregate. Measurements of Young…
Abstract Determination of crystallinity of ethylene–vinyl acetate copolymers according to the usual x‐ray diffraction method employed for polyethylene is very much hampered by the fact that these copolymers are usually largely amorphous and the Bragg reflections in their diffraction diagrams which are therefore broad…
An in situ x-ray investigation of gold films has been carried out. Films were deposited on glass near 80 °K in high vacuum. Measurements were made on the as-deposited films as well as after annealing at temperatures up to 370 °C. In the as-deposited films the following results were obtained: (1) The lattice parameter…
Both diffusional creep and sintering involve mass transport of the stoichiometric group of atoms AαBβ. The driving force in each case is external to the lattice, being applied mechanical stress in the case of diffusional creep and surface tension in the case of sintering. It is assumed that point defect mechanisms are…
Time-resolved fluorescence spectra of several europium chelates have been measured using the stroboscopic time-resolution technique. For each of the β-diketone chelates, where the ligand triplet levels are in general above the 5D1 level of Eu3+, the spectra provide evidence that the Eu3+5D0 state is populated by nonra…
Arguments are presented which conclude that the mean density of mobile dislocations in a crystalline solid increases linearly with plastic strain for small strains and decays exponentially for large strains, all at constant stress and low temperatures. The resulting analytic expression combined with the strain-rate eq…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExchange of Deuterium with the Hydroxyl Groups of AluminaJ. L. Carter, P. J. Lucchesi, P. Corneil, D. J. C. Yates, and J. H. SinfeltCite this: J. Phys. Chem. 1965, 69, 9, 3070–3074Publication Date (Print):September 1, 1965Publication History Published online1 May 2002Publish…