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E. A. Gomin V. D. Davidenko A. S. Zinchenko I. K. Kharchenko 《Physics of Atomic Nuclei》2017,80(8):1392-1398
An algorithm for calculation of the neutron importance function and the delayed neutron effective fraction by the Monte Carlo method implemented in the KIR program is presented. The results of calculation of the delayed neutron effective fraction in some critical experiments are given in comparison with the experimental results. 相似文献
256.
Tolmachev A. A. Mitrokhin A. Yu. Kharchenko A. V. 《Russian Journal of General Chemistry》2002,72(8):1254-1255
Direct phosphorylation of 4-(1-cyclopent-1-enyl)anisole with PBr3 was carried out. The resulting compound initially exists in two tautomeric forms. Isolation of the dibromophosphine and its further trans- formations lead to formation of a single tautomer. 相似文献
257.
The paper considers the problem of constructing a basic iterative scheme for solving systems of linear algebraic equations with unsymmetric and indefinite coefficient matrices. A new GMRES-type algorithm with explicit restarts is suggested. When restarting, this algorithm takes into account the spectral/singular data transferred using orthogonal matrix relations in the so-called QR form, which arise when performing inner iterations of Arnoldi type. The main idea of the algorithm developed is to organize inner iterations and the filtering of directions before restarting in such a way that, from one restart to another, matrix relations effectively accumulate information concerning the current approximate solution and, simultaneously, spectral/singular data, which allow the algorithm to converge with a rate comparable with that of the GMRES algorithm without restarts. Convergence theory is provided for the case of nonsingular, unsymmetric, and indefinite matrices. A bound for the rate of decrease of the residual in the course of inner Arnoldi-type iterations is obtained. This bound depends on the spectral/singular characterization of the subspace spanned by the directions retained upon filtering and is used in developing efficient filtering procedures. Numerical results are provided. Bibliography: 9 titles. 相似文献
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V. G. Kharchenko S. N. Chalaya L. G. Chichenkova 《Chemistry of Heterocyclic Compounds》1981,17(6):557-560
1-Alkyl-substituted 1,5-diketones react with sulfurous reagents (H2S and P4S10) to give thiopyrylium salts primarily via a mechanism that is competitive with disproportionation. The reaction depends on the nature of the acidic reagent. Some properties of the compounds obtained are described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 762–766, June, 1981. 相似文献