Growth of K(DxH1 − x )2PO4 single crystals from solutions in the K2O-P2O5-(D, H)2O system

Based on the analysis of the K₂O-P₂O₅-D₂O solubility phase diagram, the optimum conditions of KD₂PO₄ crystallization—the compositions of mother solutions and the temperature range of crystallization—in the KH₂PO₄-D₂O system have been determined. The technique of K(D_xH_{1 ? x} )₂PO₄ growth is developed. The DKDP single crystals with deuterium concentration up to 88 wt % are grown on DKDP seeds from KH₂PO₄ solutions in D₂O by the method of temperature decrease.     

Asymptotic stability of the numerical solution for an integrodifferential reaction-diffusion system

This paper presents the study of the numerical solution of a reaction-diffusion system involving a reaction term of integral type arising from biological models. By means of a monotone approach we introduce upper and lower solutions and then we show the existence and the asymptotic behavior of nonnegative numerical solutions. To this end, we require the positivity of the numerical scheme and so we can use some properties of positive and M-matrices. Finally we give some sufficient conditions to verify the asymptotic stability of the numerical solution.     

Spatial regularities in the effect of locking of photon echo signals and associative optical memory

The efficiency of suppression of the generation of a photon echo response depending on the mutual spatial orientation of gradients of external nonumform electric fields acting on a resonant medium is studied. The possibility of creating an associative memory where the mutual orientation of the gradients of external electric fields is an associative key is discussed.     

Reaction of furan compounds with hydrogen peroxide in the presence of vanadium catalysts

The reactions of furan and a number of its derivatives (furfural, furan-2-carboxylic acid, 2-furfuryl alcohol, and others), in systems containing H₂O₂ and vanadium compounds, proceed through a mechanism of radical hydoxylation of the furan ring with the formation of 5-hydroxy-2(5H)-furanone and maleic acid. The total yield and ratio of the synthesized compounds depend on the reaction conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1462–1467, November, 1991.     

The role of the spontaneous electrooptical effect in the formation of electroholographic properties of strontium barium niobate crystals

The possibility of usage of the spontaneous electrooptical (EO) effect in strontium barium niobate (SBN) crystals for the creation of controlled electroholographic elements is studied. It is found that unipolar EO properties of these crystals with respect to switching their spontaneous polarization make it possible to devise field-controlled holographic elements with reversible energy-independent memory for spatial position of an optical beam.     

Simulation of the thermal fragmentation of fullerene C60

Defect formation and annealing processes in fullerene C₆₀ at T = (4000–6000) K are studied using molecular dynamics with a tight-binding potential. The cluster lifetime until fragmentation, which proceeds, as a rule, through the loss of a C₂ dimer, has been found as a function of temperature. The activation energy and the frequency factor in the Arrhenius equation for the fragmentation rate have been found to be E _a = (9.2 ± 0.4) eV and A = (8 ± 1) × 10¹⁹s^?1. It is shown that fragmentation can occur already after the C₆₀ cluster loses its spherical shape. This fact must be taken into account in theoretical calculations of E _a.