ChemInform Abstract: THE CRYSTAL STRUCTURE OF MAGNESIUM TETRAMETAPHOSPHATE, MG2P4O12
Abstract Die Kristallstruktur von (I) wird durch direkte Methoden bestimmt und anhand von 3‐dimensionalen Röntgenbeugungsdaten verfeinert.
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Raman study of polar phonons in lithium sulphate monohydrate
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…
Optical anisotropy in GaSe
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…
The low-temperature thermal conductivity of polyethylene
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
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…
Effects of diffusion on gaseous cavitation bubbles
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…
Determination of the crystal symmetry of the polymorphs of thallium indium disulfide, TlInS2
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.…
Incorporation of Radioactive Spent Ion Exchange Resins in Plastics
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…
Birefringence studies of the stress-induced crystallization of rubbers
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…
Geometrical ambiguities in the indexing of powder patterns
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…
The Magnetocrystalline Anisotropy Constants of Iron and Iron-silicon Alloys
The magnetocrystalline anisotropy constants k 1 , k 2 and k 3 of iron and of alloys of 1.75, 2.46, 3.56 and 4.59 weight per cent silicon in iron have been measured in the temperature range 4.2-295 K. The measurements have been performed on spherical samples. The field dependence of the anisotropy constants K n ( n = 1…
Electrical Conductivity and Phase Transformation Studies on Pure and Doped (Mg2+, Zn2+, Cu2+, and Mn2+) Crystals of K2SO4
Electrical conductivity measurements have been made on single crystals of undoped potassium sulfate and on single crystals of K 2 SO 4 doped with divalent ions, viz. Mg 2+ , Zn 2+ , Cu 2+ , and Mn 2+ . The presence of the divalent ion increases the cation migration energy. The lower defect formation energy is attribut…
Decrease in the void growth rate by interstitial trapping
Void growth during neutron or charged-particle irradiation at temperatures in the range 0.4Tm⩽T⩽0.6Tm is described in pure metals and in metals containing impurities which trap interstitials. It is shown that the equations for the steady state can be integrated analytically. For cases in which strong trapping occurs t…
Tritium Absorption in Type 304L Stainless Steel
Tritium absorption was determined in Type 304L austenitic stainless steel by analyzing concentration gradients obtained during prolonged exposures to high-pressure gaseous tritium. The calculated tritium diffusivities at temperatures greater than 373 K were shown to be in excellent agreement with the equation where m…
The sintering of open and closed porosity in UO2
High green density UO2 powder compacts were annealed over a range of temperatures to establish the sintering mechanisms for open and closed porosity. During the intermediate stage of sintering the interconnected porosity was found to sinter at a rate consistent with a volume diffusion process dependent on the instanta…
Relation between the crystal structure of polymers and the elastic modulus of polymer crystals in the direction perpendicular to the chain axis
The elastic moduli Et of crystal lattices of polymers perpendicular to molecular chain axis are dependent on the intermolecular forces, and can be determined by an X-ray diffraction method. At first, the assumption of “homogeneous stress distribution” used in the evaluation of Et was confirmed experimentally. The Et v…
Theory of translational diffusion in nematic liquid crystals
The theory of translational diffusion in nematic liquid crystals is developed from the standpoint of hydrodynamics and molecular-hydrodynamic interactions. The anisotropy of the diffusivity is obtained and related to the orientational order parameter, viscosity coefficients, and the detailed molecular geometry. Liquid…
1, 3, 4‐Thiadiazole‐2, 5‐dithiol as a Complexing Agent II. Complexes of NiII, RhI, PdII, PtII, AuIII, and CuII
Abstract Komplexe des Ni II , Rh I , Pd II , Pt II , Au III und Cu II mit 1, 3, 4‐Thiadiazol‐2, 5‐dithiol wurden dargestellt. Auf Grund analytischer, magnetischer und spektraler Daten werden Strukturen vorgeschlagen. Kristallfeld‐Parameter wurden in Übereinstimmung mit den vorgeschlagenen Strukturen berechnet.
The vibrational spectrum of crystalline syndiotactic. Poly(vinyl chloride)
A normal vibration analysis has been carried out for crystalline syndiotactic poly(vinyl chloride) and its deuterated derivatives. This was based on a general valence force field derived from an analysis of the spectra of small secondary chloride molecules. The calculations permit a very satisfactory assignment to be…
A Convenient Preparation of meso-Tetra(4-sulfonatophenyl)porphyrin
The sulfonation of meso-tetraphenylporphyrin, in concentrated sulfuric acid followed by neutralization and dialysis, provides an efficient and convenient route to meso-tetra(4-sulfonatophenyl)porphyrin.