A “nonlinear” generalization of special functions of wave catastrophes described by double integrals

Translated from Matematicheskii Zametkii, Vol. 52, No. 5, pp. 102–106, November, 1992.     

Crystal structure of uranyl tungstate Cs2U2WO10

A representative of uranyl tungstates Cs₂U₂WO₁₀ has been synthesized. A single crystal X-ray diffraction experiment has been performed for the compound prepared and its crystal structure has been solved. It is monoclinic, space group P2₁/n, a = 8.4611(5) Å, b = 28.691(2) Å, c = 9.6499(6) Å; β = 107.073(1)°, R ₁ = 0.086 for 4599 independent reflections with I > 2σ(I). The crystalline structure of the compound is formed by infinite negatively charged layers [U₂WO₁₀] _2∞ ^δ? interleaved with cesium cations which bond the layers. The compound has been studied with IR spectroscopy, and absorption bands of its spectrum have been assigned.     

The Influence of Technological Regimes of Synthesizing a Solar Furnace on the Phase Composition of TiO<Subscript>2</Subscript>-CuO Cermets and the Optical Properties of Coatings on Their Basis

We present the results of studying the effect of technological synthesis regimes of a solar furnace using the method of a partial metal reduction of one of the oxides on the phase formation of cermet composite materials of the TiO₂-CuO system. It has been established that the phase composition of the synthesized cermet composite materials depends on the carbon concentration, melting temperature and cooling rate. The dependence of the spectral-optical properties of selectively absorbing coatings on the production technology and properties of synthesized composite materials has been presented. It has been found that the coatings fabricated by melting in air with overheating at a melt cooling rate of about 105–106°C/s have the highest values of the integral absorption coefficient, α _s = 91.0–94.5%.     

On-line delta(18)O measurement of organic and inorganic substances

A method for the automated sample conversion and on-line oxygen isotope ratio (delta(18)O) determination for organic and inorganic substances is presented. The samples are pyrolytically decomposed at 1400 degrees C in the presence of nickelized graphite. With the system presented organic as well as inorganic samples such as nitrates, sulphates and phosphates of 50-100 &mgr;g O can be analyzed for their delta(18)O values with a standard deviation usually better than 0.5 per thousand. Additionally, carbon isotope ratios of organic substances and nitrogen isotope ratios of inorganic nitrogenous compounds are available in the same sample run. Data for international and some inter-laboratory reference materials are presented to show the accuracy and reliability of the method. The effect of some additives on the CO yield was checked for substances which do not pyrolyze completely. Copyright 1999 John Wiley & Sons, Ltd.     

Optical spectra and electronic transitions in gallium phosphide crystals

Analysis of the long-wave edge of the self-absorption spectrum of gallium phosphide crystals not distorted by line structure at low temperatures enabled us to determine the characteristic parameters of indirect transitions. In GaP crystals of a different type the appearance of a discrete structure in the long-wave absorption edge is related to the localization of excitons near impurities of an unknown nature. This is confirmed by the appearance in these crystals of an intense green electroluminescence band at low temperatures.The authors are grateful to I. Ryzhikov, A. Kruchinin, and Yu. Il'in for providing the crystals used in the experiments.