Materials Literature
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The thermal conductivity of a number of samples of vitreous silica has been measured between 1.5 and 20 K and between 65 and 300 K. The specimens were obtained from a number of manufacturers and were all high-purity optical-quality material. Above 65 K, the thermal conductivities of all the specimens were found to be…
A previous model calculation of the kinetics of hole diffusion in thallium-activated alkali iodides led to predictions concerning the role of binary electron-hole diffusion in the energy transport associated with the scintillation process. In this paper we report the resuls of time-resolved emission and absorption mea…
An attempt is made to locate the energy levels associated with iron and aluminum in the band gap of SrTi${\mathrm{O}}_{3}$. A relative energy-level scheme for these impurities is derived from data in the literature, principally ESR and optical absorption. Measurements of thermally stimulated current, electrical conduc…
Neutron scattering and specific-heat studies of the crystal fields in the rare-earth monophosphides are reported. It is found that the fourth-order crystal-field parameters for the phosphides and for other rare-earth pnictides fall on a universal curve which is close to that predicted by an effective-point-charge mode…
The electronic band structures of the ferroelectric semiconductor SbSI, whose crystal structure is very complex compared with the crystals for which the band calculations have been made up to the present, have been calculated by the pseudopotential method in the para- and ferroelectric phases. It is shown that this ma…
A detailed phenomenological theory of the triplet luminescence from self-trapped excitons in halide crystals is developed. Energy levels and wave functions are obtained by constructing and diagonalizing a Hamiltonian matrix. Coupled rate equations for the decay of the three lowest triplet levels are solved for the gen…
The empirical relation ${E}_{0}\ensuremath{\propto}(\frac{1}{{a}_{0}^{2}})$ between the energy gap ${E}_{0}$ and lattice constant ${a}_{0}$ has been found to hold for a wide range of semiconductors with the cubic NaCl crystal structure.
X-ray photoemission spectra of valence and core electrons in sodium and sodium hydroxide were measured from clean and oxidized sodium-metal films. Clean metal surfaces were prepared by sequential evaporation, with the resultant films contaminated by less than half a monolayer of impurity after 8 h running time. From t…
Optical-absorption-edge measurements and Raman scattering experiments on ${\mathrm{Ge}}_{x}{\mathrm{Se}}_{1\ensuremath{-}x}$ glasses are reported for the range $0\ensuremath{\le}x\ensuremath{\le}0.4$. The change in the magnitude of the main peaks of Raman spectra (localized about 195, 215, and 250 ${\mathrm{cm}}^{\ens…
Mutual solubilities of 14 paraffinic and 6 aromatic hydrocarbons and water were determined experimentally at 0 and 25 °C. The solubilities are generally smaller at 0 than at 25 °C except the solubilities of paraffins in water which are larger at 0 than at 25 °C. The coefficients of the Redlich–Kister equation were eva…
Article Pyroxenes: comparisons of real and ideal structural topologies was published on December 1, 1973 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 138, issue 1-6).
Abstract A simple method is described for making infrared measurements on solids at temperatures up to the melting point of KBr by using a fine nichrome heating coil wound directly on to the KBr disc containing the sample either in suspension or sedimented on to the surface. The usefulness of the method is illustrated…
The paper outlines the way in which the constructive method obtained for symmetrizing nth Kronecker powers of induced representations (see ibid., vol. 6, no. 12, 1807 (1973)) may be applied to space group representations. Also a step by step procedure is given for finding the symmetrized cubes of space group represent…
A general expression for the creep strain produced by a distribution of dislocation loops is derived and applied to the nucleation (assumed subject to Boltzmann statistics) of prismatic loops in b.c.c. and f.c.c. metals and alloys subjected to neutron irradiation. The nucleation of the loops is considered to take plac…
The magnetic susceptibilities of a series of $\ensuremath{\alpha}$-phase Cu-Al and dilute magnetic Cu-Al(Fe) alloys with Fe concentrations near 0.07 at.% have been measured over the temperature interval from 1.5 to 300 K and at six magnetic fields in the range from 3.95 to 12.75 kOe. The alloys had Al concentrations o…
Abstract A method for obtaining triacetate having a D.S. of 3.0 has been obtained by acetylating the cellulose with acetic anhydride–pyridine reagent containing a catalytic amount of acetyl chloride. The process is rapid and nondegradative. Cellulose tricarbanilate can be prepared without recourse to pyridine solution…
Groove profiles from a number of diffraction gratings have been examined with the Talystep using a 0.1 mu m stylus. Useful results have been obtained with groove densities up to 1200 mm -1 . The method has some advantages over electron microscope techniques.
The relationship between photoelectric work function and impurity concentration (sulfur) on the Fe (100) surface was investigated by Fowler's method combined with Auger electron spectroscopy (AES). Sulfur was separated markedly when the sample was heated at higher temperatures. As sulfur on the sample surface increese…
Growth behaviour of four individual voids has been studied using 1 MeV electron irradiation in a high voltage electron microscope. Direct evidence is presented to show that the growth rate of voids is reduced markedly as the distance between the growing voids and grain boundaries becomes smaller than the ‘defect deple…
The boundary value problem posed is a truncated cylindrical region excited by a specified distribution of electric current over a concentric cylindrical surface. The end conditions are that the total normal current density is zero. The solution is carried through for excitation by a symmetrically located axial current…