Amplified spontaneous emission and its application for population of resonant states of the Xe and Kr atoms

To extend the capabilities of the existing spectroscopic methods of investigation and diagnostics of gaseous media, we consider a macroscopic effect of an increase in the rate of spontaneous emission, which results in the transition of a considerable part of excited molecules to lower-lying optically accessible states with light pulse emission along the direction of propagation of the exciting laser radiation. As an application of the effect of amplified spontaneous emission, we propose the population with its help of optically inaccessible electronic states of atoms and molecules.     

On estimates of the bispectral density of certain models of random processes

Estimates are given for the bispectral densities of stationary random processes. Two models of stationary random processes with discrete time are considered. It is shown that for both models conditions hold under which one can construct a consistent estimate of the bispectral density.Translated fromTeoriya Sluchaínykh Protsessov, Vol. 14, pp. 3–7, 1986.     

IR spectra of selenophenopyrylium salts

On the basis of the IR spectra of 16 alkyl-substituted selenopheno[2,3-c]- and selenopheno-[3,2-c]pyrylium salts and a model calculation of the frequencies and the forms of their normal vibrations, an assignment of the frequencies of the skeletal vibrations of the heterocycles is put forward.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1495–1497, November, 1973.     

Heterocyclization of compounds containing diazo and cyano groups. 3. Two pathways in the cyclization of 2-diazo-2-cyanoacetic acid derivatives under the influence of bases

1,2,3-Triazol-5-olates are formed in the reaction of diazomalonodiamide and 2-diazo-2-cyanoacetic acid amide and N-methylamide with sodium ethoxide, triethylamine, and ammonia. The products of the reaction of 2-diazo-2-cyanoacetamide with primary amines are mixtures of 4-cyano-1,2,3-triazol-5-olates and 5-amino-1-alkyl-1,2,3-triazole-4-carboxamides.See [1] for communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 926–931, July, 1986.     

Synthesis of thieno [3,4-c ]- and selenopheno[3,4-c] pyrylium salts

Acylation of 3-acetonyl- and 3-phenacyl-2,5-dimethylthiophenes with aliphatic acid anhydrides in the presence of perchloric acid gives thieno[3,4-c]pyrylium perchlorates. Reaction of the latter with ammonia gives the corresponding thieno[3,4-c]pyridines or diketones of the thiophene series. Selenopheno[3,4-c]pyrylium salts could not be isolated in the acylation of 3-acetonyl- and 3-phenacyl-2,5-dimethylselenophenes.     

Crystal structure of KAsUO<Subscript>6</Subscript>·<Subscript>3</Subscript>H<Subscript>2</Subscript>O at 100 and 293 K

The crystal structure of KAsUO₆·3H₂O was solved at 100 K and 293 K. KAsUO₆·3H₂O at T = 100 K: tetragonal, P4/ncc, a = 7.2037(6) Å, c = 17.811(2) Å; Z = 4, R1 = 0.0263, wR2 = 0.0546, for 618 independent reflections; at T = 293 K: tetragonal, P4/ncc, a = 7.1600(4) Å, c = 17.746(1) Å; Z = 4, R1 = 0.0263, wR2 = 0.0433 for 427 independent reflections. The results of X-ray analysis are compared with our previous data on heat capacity of this compound, and changes that take place in the structure at elevated temperature are considered.     

Crystal structural study of ternary molybdate LiRbBi2(MoO4)4

Single crystals of the title compound have been synthesized and its crystal structure has been determined. The compound crystallizes in the monoclinic system, space group C2/c, Z = 2 (a = 5.3056, b = 12.976, c = 19.578 Å, = 92.583°, R = 0.029). A distinctive feature of the structure is lacy layers of eight-vertex Bi polyhedra and Mo tetrahedra connected to them via common vertices. me adjacent layen are linked together by ten-vertex Rb polyhedra and Li octahedra.Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Buryatian Institute of Natural Sciences, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 152–156, September–October, 1993.Translated by T. Yudanova     

Influence of the gamma-ray fraction in the reactor radiation on the total signal of a self-powered neutron detector

For controlling the linear power density in the reactor core, the Khortitsa-M software program as a part of the in-core instrumentation system (ICIS) employs only self-powered neutron detector (SPND) data with the neutronic calculation for the consistent determination of the power density in unmeasurable fuel assemblies (FAs). The confidence of the interpretation of the SPND data essentially determines the safe and efficient operation of a reactor. Previously, it was assumed that the gamma-ray fraction in the reactor radiation does not exceed one percent and is independent of the fuel enrichment and the FA and SPND burnups. Since it is difficult to estimate the contribution of the reactor gamma radiation to the SPND current experimentally, in this work, we present a calculated estimate using modern software and libraries of constants. On the basis of the results of this study, the question is discussed whether it is appropriate to take into account the reactor gamma radiation in the transfer function from the SPND current to the power density of six fuel elements surrounding the SPND with allowance for both the type of FA and the FA and SPND burnups.