Materials Literature
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Crystals of BaNaPO 4 were grown from a Ba 3 P 2 O 8 –Na 2 B 4 O 7 melt. The crystals are trigonal, space group [Formula: see text]with a = 5.622(4) and c = 7.259(5) Å. The structure, isotypic with that of glaserite, was refined by full-matrix least-squares methods to a final R value of 0.042 using 218 unique reflectio…
The decay of the excited $^{4}S_{\frac{3}{2}}$ state of ${\mathrm{Er}}^{3+}$ ions in La${\mathrm{F}}_{3}$ at 295\ifmmode^\circ\else\textdegree\fi{}K has been investigated in detail. The energy is transferred from the thermally populated multiplet $^{2}H_{\frac{11}{2}}$. The decay curve of the luminescence from $^{4}S_…
An X-ray integral breadth analysis has been made for the 111, 200, 220, 311 and 222 diffraction profiles recorded on a Geiger counter X-ray diffractometer from the vacuum-evaporated thin films of silver in the range of thickness 580 to 2125 Å. The analysis based on the methods of single and multiple order of reflectio…
Spontaneous magnetostriction of NiO, which consists of two strain components, is reexamined in detail by Berg-Barrett method. The strain components thus determined are e x ' x ' -e y ' y ' =-5.4×10 -4 and e z ' x ' =0.91×10 -4 , respectively. These values are a few times as large as those found previously by Yamada et…
The general spin-relaxation theories of Albers and Deutch and of Argyres and Kelley based on different projection operator methods, and the theory of Freed based on generalized cumulant expansions are compared. It is shown that the first two yield equivalent expressions for the time evolution of the spin density matri…
Measurements are reported of the total charge and its mean position in liquid-charged FEP electrets. A new nondestructive technique has been used. The large difference in decay rates of positive and negative liquid-charged electrets is accompanied by quite different behavior of the deposited charge as it migrates thro…
The interface excitations associated with the inversion layer of a metal-insulator-semiconductor structure are investigated. These excitations can be regarded as coupled modes whose components are the two-dimensional-electron-gas plasmon and the surface plasmon of the metal-insulator interface. The dependence of the c…
The Onsager theory of dissociation has been used to explain the electric field, excitation wavelength, and temperature dependence of photogeneration in amorphous selenium. The Onsager theory was formulated to explain the departure from Ohmic behavior in either weak electrolytes or solid dielectrics, and the analysis o…
An analysis of low-energy-electron-diffraction data from a clean Mo{001} surface was carried out, which has determined the atomic structure of this surface and provided the parameters of a scattering model needed to analyze ordered overlayers. The analysis was based upon the comparison between the intensity spectra ca…
Detailed light and electron microscopical studies on the diatom genus Berkeleya Grev. clarify relationships between the four species and support the separtion of B. fragilis and B. micans as two distinct taxa.
Abstract Die Kristallstruktur von (I) wird durch direkte Methoden bestimmt und anhand von 3‐dimensionalen Röntgenbeugungsdaten verfeinert.
A detailed Raman study of phonons in monoclinic Li 2 SO 4 H 2 O and its deuterate is given. The spectrum for two directions of the phonon wave vector at 45 degrees to the y axis from liquid nitrogen to room temperature have been determined and the majority of the lines observed have been identified: although the conve…
Normal-incidence reflectivity spectra of layer-type beta -GaSe crystals have been measured for E perpendicular to c as well as E//c at 78K. A strong anisotropy in the selection rules for interband transitions has been observed and a suitable energy level scheme is proposed. The reflectivity spectra of the mixed polyty…
Measurements are presented of the temperature variation between 2K and 100K of the thermal conductivity, kappa of several samples of extruded polyethylene. At high temperatures ( approximately 100K) there is an anisotropy in kappa , with the values measured parallel to the extrusion direction up to 5 times greater tha…
Optical theorems for three-to-three processes are derived from S-matrix principles. These theorems express all single, double, and multiple discontinuities across all combinations of normal threshold cuts in terms of physical scattering amplitudes. The 216 functions corresponding to all combinations of sides of the 16…
Rectified diffusion is a mechanism whereby a gas bubble, set into pulsation by a sound field, grows in size because of an effective gating action by the bubble surface area. Bubbles that might otherwise dissolve will grow instead if the sound pressure amplitude exceeds a threshold that depends on the bubble size. A th…
Several modifications of TlInS 2 crystallize from melts of this composition with annealing at various temperature. Symmetries and lattice parameters determined by the x-ray precession method are as follows: I. ( = β ), monoclinic, a ∼ b = 7.76 ± 0.01 Å, c = 30.01 ± 0.02 Å, β = 90°10′ ± 5′, P 2 1 / m , Z = 16, D x = 5.…
Experiments were undertaken on the incorporation in plastics—polyethylene in particular—of radioactive spent ion exchange resins produced in nuclear power plants. The resulting polyethylene products burdened with radioactive resin were tested to ascertain the properties considered important for radioactive waste manag…
The change in the fraction crystallinity with time and elongation of synthetic cis-1,4-polyisoprene is studied through simultaneous measurement of birefringence and stress. Results are compared with values estimated from the decrease in stress arising from the crystallization. Various methods for calculating the cryst…
There are cases in which different lattices give calculated powder patterns with the identical number of distinct lines in identical 20 angular positions. The number of planes (hkl) contributing to each reflection may differ, however. The lattices having this property are related to each other by transformation matric…