Materials Literature
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The kinetic energy spectrum of photoelectrons ejected from ammonia by monochromatic 584 Å (21.21 eV) radiation has been determined using a spherical grid energy analyzer. Ionization potentials of 10.35 and 14.95 eV have been deduced from the spectrum and the relative transition probabilities to the ionic states have b…
Cesium methylsulfonate, CsCH 3 SO 3 , crystallizes in space group Pnma with a = 9.526, b = 6.264, and c = 8.692 Å. Three-dimensional X-ray diffraction data have been collected photographically and refined to give a weighted agreement index (R) of 0.12. The structure is related to, but is not identical with, that of th…
The crystal structures of RuS 2 , OsS 2 , RuTe 2 , and OsTe 2 were refined isotropically by least squares from powder diffractometer data using individual temperature factors. The resulting positional parameters of the chalcogen atoms in these C2-type structures are 0.3879 ± 14, 0.3865 ± 19, 0.3739 ± 9, and 0.3725 ± 1…
The Hall coefficient ${R}_{H}$ and resistivity $\ensuremath{\rho}$ have been measured on ceramic samples of $p$-type CoO and NiO between 200 and 1500\ifmmode^\circ\else\textdegree\fi{}K and of $n$-type $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ between 960 and 1500\ifmmode^\circ\else\textdegr…
The magnetoresistance of semiconducting SrTi${\mathrm{O}}_{3}$ has been investigated in high magnetic fields (up to 150 kOe). In the temperature range 1.4-2.1 \ifmmode^\circ\else\textdegree\fi{}K, for fields of more than 50 kOe, well-developed Shubnikov-de Haas-type oscillations have been observed. The data support a…
The identification of the layer sequences of the polytypes listed above is reported. The birefringence of these structures is also given. Two of the identified structures [14L (7 7) and 24L (7 5 5 7)] have unitcell dimensions identical with those of structures previously reported [14L (5 4 2 3) and 24 L(5 3)3 respecti…
The zero-point phonon vibrations in a paramagnetic crystal are shown to give rise to an effective ion-ion coupling. Expressions are derived for ion-energy transitions $\ensuremath{\Delta}$ both greater and less than the phonon-cutoff energy $\ensuremath{\hbar}{\ensuremath{\omega}}_{0}$. In the former case, the couplin…
Abstract : Compounds with chemical formula MNb2S4 where M is one of the divalent transition metals Mn, Fe, Co, Ni, Cu were synthesized. The lattice constants of these compounds, isomorphous with berthierite (FeSb2S4), were determined from the powder diffraction data, using Cohen's analytical method. (Author)
The structures of the 0~ alums K, Rb and NH4AI(SO4)z. 12H20 have been refined using single-crystal X-ray diffraction data. The ~ alums are disordered, some of the sulfate groups being in a reversed orientation along the threefold axis. The fraction of reversed sulfate groups apparently increases as the monovalent cati…
Neutron-diffraction measurements have been made on single-crystal holmium at temperatures ranging from 4.2 to 120\ifmmode^\circ\else\textdegree\fi{}K in applied magnetic fields up to 22.3 kOe in order to study the magnetization process of this material. At low temperatures, the $b$ direction in the basal plane is an e…
We present the results of a detailed theoretical and experimental investigation of the $^{6}A_{1g}$ to $^{4}T_{1g}$ optical absorption in Mn${\mathrm{F}}_{2}$. This transition is one in which a spin-wave sideband was identified in an earlier communication. A collective-mode theory of the excitations associated with th…
The crystal structure of fresnoite, Ba(2)(TiO)[Si(2)O(7)], consists of [Si(2)O(7)](6-) double groups and titanium-centered square pyramids linked to form flat sheets. Intercalated between these sheets are Ba(2+) ions in highly distorted pentagonal antiprisms. The structure of fresnoite is related to that of melilite,…
Abstract The mechanical properties of pure iron single crystals and of polycrystalline specimens of a zone-refined iron have been measured in compression over the temperature and strain rate ranges 2.2 to 293 °K and 7 x 10-7 to 7 x 10-3 s-1 respectively. Various yield stress parameters were determined as functions of…
A study of the velocity autocorrelation function for hard spheres over the entire fluid density region shows that deviations from exponential behavior are small. At very low density a small positive deviation is found which is accounted for in the Boltzmann theory of the self-diffusion coefficient. At higher densities…
Abstract The thermal degradation of polypropylene was investigated in the presence of polyglycidyl methacrylate (PGMA) by the use of an extruder under a nitrogen atmosphere. PGMA was found to be effective as an accelerator for the thermal degradation of polypropylene. The accelerating effect of PGMA was attributed to…
The purpose of the persent work is to evaluate the heat of formation of uranium sesquinitride, U2N3. The U2N3 phase is known to form a single solid solution with UN2, while the U2N3 compound with minimum N/U ratio is in equilibrium mith UN under a given condition of temperature. The heat of formation for the terminal…
The galvanomagnetic parameters ρ123, ρ1111, ρ1133, ρ1131, and ρ1122 have been measured at 77°K for two samples of p-type (Bi2Te3)5(Bi2Se3)1 (Sb2Te3)18 and the results fitted to a six-ellipsoid model similar to that proposed for Bi2Te3. An anomalous rise in the Hall coefficient with temperature and an apparent change i…
The design of an electron velocity analyser, based on an electrostatic einzellinse which incorporates a fine mesh in the centre electrode, is described. Measurements made on a low-energy electron beam show no sign of any broadening of the emission velocity spectrum, i.e. of the so-called `Boersch effect'.
Calcium aluminate and calcium silicate hydrates were formed in mixtures of bentonite with water and various types of lime which had been sealed and cured for up to three years at 23°± 2°C and 100% relative humidity. Methods of analysis were X‐ray diffraction and electron microscopy. Hydrothermal treatment of the cured…
Abstract Die Korrosionsgeschwindigkeiten von 13/1‐CrNi‐, 13/4‐CrNi‐, 12/5/1‐CrNiMo‐ und 14/5/1‐CrNiMo‐Stahlguß werden in 3%iger NaCl‐Lösung, Meerwasser und in 2 n H 2 SO 4 mit bis zu 0,35 n NaCl auf elektrochemischem Wege durch Messung der Steigung der Stromdichte‐Potential‐Kurve beim Korrosionspotential sowie chemisc…