The amplitude and phase of a transmission holographic grating due to four-wave interaction in a photorefractive medium

Based on a previously developed two-level model of four-wave interaction in photorefractive crystals, expressions for the amplitude and phase of a transmission holographic grating have been obtained. The analysis of these expressions points to the dependence of both the amplitude and the phase of the grating on the intensity of the readout beam.     

Hydrogenated α-methylstyrene dimers as friction fluids and rubber plasticizers

Hydrogenation of α-methylstyrene dimers was studied. The possibility of using hydrogenated dimers as friction fluids and rubber plasticizers was examined.     

The Ga2S3?;Eu2O2S System

By the methods of differential thermal, high-temperature differential thermal, X-ray phase shift, microstructural analyses and also by the measurement of microhardness and density interactions in Ga₂S₃? ;Eu₂O₂S system have been investigated. The existence of three new phases of composition (EuO)₂Ga₄S₇, EuGaOS₂, (EuO)₄Ga₂S₅ has been revealed in the system. The eutectic coordinates correspond to 12 mole-% of Eu₂O₂S and 1210 K. The solubility on the basis of Ga₂S₃ at 295 K reaches 1 mole-% of Eu₂O₂S.     

The photolysis and radiolysis of H2S−CH4 gas-phase mixture

The purification of methane from hydrogen sulphide at room temperature as affected by U.V.-light and ionizing radiation has been studied. A probable reaction mechanisms is discussed.     

Clebsch-Gordan coefficients and two-phonon resonance Raman scattering in cubic crystals

The intensity of two-phonon resonance Raman scattering in cubic crystals is expressed in terms of Clebsch-Gordan coefficients. A plot of the scattering intensity against the direction angles of the polarization vectors of the incident and scattered radiation is obtained. Several useful polarization relations are obtained for the scattering intensities in experiments with different geometries.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 75–80, August, 1978.     

Positive feedback effect in four-wave mixing in photorefractive crystals with absorption

Using a two-level model of optical transitions, the positive feedback effect observed in the presence of absorption in four-wave mixing in photorefractive crystals has been determined analytically. It is shown that with positive feedback, as the intensity of readout beam increases, the values of diffraction efficiency and intensity of amplified beam also increase. An analysis of the holographic grating amplitude shows that the effective thickness of the grating decreases in this case, but its amplitude increases. The dependences obtained, very important from the practical point of view, show that the optimal thickness of the crystal is different for diffraction efficiency and intensity of the amplified beam, and decreases with increasing readout beam intensity.     

Dispersion laws of current carriers in diamond-type crystals

Dispersion laws for the current carriers are obtained when the spin-orbital interaction is neglected and taken into account, and the wave functions of heavy holes are calculated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 12–17, January, 1988.It remains to thank Prof. F. M. Gashimzade for extensive discussion of the results obtained.     

Quantum systems and representation theorem

In this paper we investigate quantum systems which are locally convex versions of abstract operator systems. Our approach is based on the duality theory for unital quantum cones. We prove the unital bipolar theorem and provide a representation theorem for a quantum system being represented as a quantum $L^{\infty }$ -system.