Materials Literature
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The effective shear moduli, dislocation line energies, dislocation widths, and relative ease of gliding have been calculated for the (0001) [112̄0], (11̄00) [112̄0], (11̄01) [112̄0], (112̄2) [112̄3̄], and (hk.0) [0001] slip systems in each of the hexagonal close-packed metals Cd, Zn, Mg, Co, Zr, Ti, and Be by applying…
Simultaneous decomposition of yttrium and zirconium alkozides was used to obtain an almost ideal mixture of powders of high surface activity. From this powder a translucent body, “Zyttrite,” was made with a grain size of less than 1μ. The mixed oxide was consolidated into a stabilized body by firing at 1000°C for 30 m…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHypersensitive transitions of six-, seven-, and eight-coordinate neodymium, holmium, and erbium chelatesDavid G. KarrakerCite this: Inorg. Chem. 1967, 6, 10, 1863–1868Publication Date (Print):October 1, 1967Publication History Published online1 May 2002Published inissue 1 Oc…
what effect altering the invasion rate had on the structure of the community. The third series of experiments was a comparison of the structure of diatom communities in structurally and chemically similar streams on the island of Dominica and in the United States. The temperature of the water in the two rivers was sim…
Synthese de resines epoxydes type glycidyl; synthese a partir d'olefines et chloroacetyls; Caracterisation de resines epoxydes non vulcanisees; Mecanisme de vulcanisation. Caracterisation d'agents de vulcanisation (amines aliphatiques primaires, aromatiques primaires, secondaires et tertiaires, amides et composes nitr…
Abstract The nature of cracks, produced in three cured polyester resins during exposure to water has been studied by the combined techniques of optical microscopy, scanning electron microscopy and electron probe X-ray microanalysis. There are many cracks totally enclosed within the resin and it is shown that these mus…
Evidence is presented in support of a postulate proposed by Hartke and Regensburger in 1965, that the absorption edge in amorphous selenium is dominated at room temperature by an exciton band. Measurements of the temperature shift of the absorption edge show that the temperature shift decreases rapidly as the absorpti…
Electron paramagnetic resonance has been observed for the systems (a) Mn(ClO4)2–Et4NClO4, (b) MnCl2–Et4NCl, and (c) MnBr2–(n-C4H9)4NBr in acetonitrile. EPR intensity measurements, linewidths of the hyperfine components, electrical conductance, and optical spectra have been used to characterize the species exhibiting t…
Infrared-absorption spectra of doped KBr crystals at temperatures of approximately 8°K were measured in the wavelength range 2 to 15 μ. From the absorption spectra of crystals doped with NO2− and NO3− ions, and with ions enriched in the isotopes 15N and 18O, frequencies of normal vibrations of six isotopic NO2− molecu…
The infrared spectra of crystalline hydrazine and hydrazine-d4 have been recorded from 33 to 400 cm−1. All spectral bands have been assigned to lattice vibrations according to whether they arose primarily from a translational motion or a librational mode. However, there is strong evidence that these two motions are co…
The 57Fe Mössbauer-effect spectra of a series of tetrahedrally coordinated Fe(II) compounds of general formula R2FeX4 have been measured over a wide temperature range. The absorption showed approximately a tenfold increase on cooling from 300° to 4.2°K, showing that the effective Debye temperature for the Fe(II) ion i…
A differential scanning calorimeter has been used to determine the latent heat of fusion of o-terphenyl, 4.40±0.07 kcal/mole, the entropy of fusion, 13.4±0.2 cal/mole·°K, and the specific heat of the liquid, glassy, and crystalline states from 220°K to the melting temperature, 328.7°K. The constants of the Adam—Gibbs…
In order to resolve some of the experimental discrepancies existing between various published optical studies of diamond, absolute near-normal incidence-reflectance measurements have been taken on a polished type-I and both cleaved and polished type-$\mathrm{II}a$ diamond crystals. These measurements covered the range…
Large corrections to the x-ray intensities of the standard powder diffraction pattern of hexagonal AgI are proposed. Based on these intensities, it appears that some precipitates which have been described in the literature as pure hexagonal have actually contained about 30% of the cubic phase. Hexagonal AgI was produc…
Experimental results are presented on current-voltage relations in heteroepitaxial silicon films grown on sapphire. Above a threshold voltage a current is observed which is proportional to the square of the applied voltage, but inversely proportional to the square of the distance. It is interpreted as space-charge-lim…
Adiabatic elastic constants of LiCl, NaF, NaCl, NaBr, KF, RbCl, RbBr, and RbI were measured at 4.2 and 300\ifmmode^\circ\else\textdegree\fi{}K, using the ultrasonic pulse-echo technique. Data are also given for several of these materials, for the temperature interval 4.2 to 300\ifmmode^\circ\else\textdegree\fi{}K. It…
We have investigated the possibility of obtaining good approximate analytical expressions for the zero field splittings of cubic terms belonging to the t23 configuration. Spin—orbit, and trigonal and tetragonal field perturbations are considered, and a perturbation expansion based on a strong cubic field zeroth-order…
Relatively weak extrinsic luminescence bands observed at low temperatures (\ensuremath{\lesssim}80\ifmmode^\circ\else\textdegree\fi{}K) in silicon doped with several different donors and acceptors are described and identified with the following recombination processes: (1) Phonon-assisted decay of excitons bound to ne…
A detailed investigation has been made of the photoconductivity response of several types of natural diamond in the spectral energy range from 3.0 to 5.9 eV. Oscillatory structure in the photoconductivity beyond the fundamental absorption edge at 5.49 eV has been shown to be closely related to similar oscillatory stru…
Energy transfer from the sensitizers (S) Sb3+, Bi3+, or Ce3+ to the activators (A) Sm3+, Eu3+, Tb3+, or Dy3+ has been studied in four different host lattices, viz., YOCl, YBO3, YAl3B4O12, and YPO4. The efficiency of the energy transfer in these systems varies markedly. This is the case even for a given combination of…