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91.
A differential inclusion with parameter on a finite time interval is studied. Questions related to determining the solvability set in the problem of guiding a differential inclusion to a compact target set in the phase space are discussed. 相似文献
92.
V. G. Ushakov N. G. Ushakov 《Moscow University Computational Mathematics and Cybernetics》2016,40(3):118-122
A single-channel queueing system with an Erlang incoming flow and random server unavailability intervals as the system releases is considered. The nonstationary and stationary distributions of queue length are obtained. 相似文献
93.
Mathematical Notes - 相似文献
94.
Bagrat A. Shainyan Igor A. Ushakov Uwe Schilde Erich Kleinpeter 《Tetrahedron》2007,63(48):11828-11837
Multinuclear dynamic NMR spectroscopy of 3,5-bis(trifluoromethylsulfonyl)-1,3,5-oxadiazinane (3) revealed the existence of two conformers with differently oriented CF3 groups with respect to the ring, and two dynamic processes: ring inversion and restricted rotation about the N-S bond. Two transition states connecting the two conformers and corresponding to clockwise and counterclockwise rotations about the N-S bond were found; the calculated activation barriers of about 12 kcal/mol are in excellent agreement with those measured experimentally for the related molecule 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane (1). X-ray analysis proved the existence of the symmetric isomer of 3, which is the minor isomer in solutions but the only one in the crystal due to packing effects. The normal Perlin effect (JCHax<JCHeq) was observed for 2(6)-CH2 in 3, whereas the reversed Perlin effect was found for the 4-CH2 group in 3 as well as for all CH2 groups in 1 both experimentally and theoretically. The latter effect in compounds 1, 3, and 1-(methylsulfonyl)-3,5-bis(trifluoromethylsulfonyl)-1,3,5-triazinane (2) can be considered as a genuine reverse Perlin effect since larger values of 1JCH are observed for longer C-H bonds. 相似文献
95.
SergeyP. Gromov ArtemI. Vedernikov EvgenyN. Ushakov LyudmilaG. Kuz'mina AlexeiV. Feofanov VitalyG. Avakyan AndreiV. Churakov YuriiS. Alaverdyan EkaterinaV. Malysheva MichaelV. Alfimov JudithA.K. Howard Bertil Eliasson UlfG. Edlund 《Helvetica chimica acta》2002,85(1):60-81
Butadienyl dyes of the benzothiazole series with various fragments of benzocrown ethers 1a – c were synthesized for the first time. The structures and spectral properties of crown‐containing butadienyl dyes and their complexes with alkali and alkaline‐earth metal cations were studied by X‐ray diffraction analysis and 1H‐NMR, UV/VIS, and resonance Raman spectroscopy. To interpret the experimental results, quantum‐chemical calculations were performed. In the case of Sr2+ and Ba2+ ions, the formation of strong sandwich complexes [M( 1b )2]2+ of an unusual structure involving stacking interactions was established; the dye molecules are arranged one above another in the complex according to the ‘head‐to‐head' pattern. 相似文献
96.
I. V. Karpov A. V. Ushakov A. A. Lepeshev L. Yu. Fedorov V. G. Demin A. A. Shaikhadinov E. A. Dorozhkina O. N. Karpova 《Technical Physics》2017,62(5):760-764
Quasi-crystalline Al65Cu23Fe12 powders have been obtained by the method of plasma-chemical synthesis. Coarse particles have a spherical form and an inhomogeneous structure because of the laminar growth of crystallites toward the surface of the particles. The influence of heat treatment on phase formation and structuring in Al–Cu–Fe alloys has been studied. It has been found that the heat treatment of as-prepared powders changes the phase relationship in the quasi-crystalline alloy. 相似文献
97.
98.
Boris A. Trofimov Elena Yu. Schmidt Igor A. Ushakov Elena Yu. Senotrusova Grigorii G. Aleksandrov 《Tetrahedron letters》2009,50(26):3314-3775
A new three-component reaction between alkyl aryl(hetaryl)ketoximes, acetylene, and aliphatic ketones in the superbasic systems KOH/DMSO and LiOH/CsF/DMSO (70-90 °C, initial acetylene pressure 13-15 atm, 5-60 min) affords novel 4-methylene-3-oxa-1-azabicyclo[3.1.0]hexanes in yields of up to 75%. Using KOH/DMSO, the side products of the reaction are O-vinylketoximes and 2-aryl(hetaryl)pyrroles, while with LiOH/CsF/DMSO, the reaction proves to be selective, only minor amounts of the corresponding alkyl aryl(hetaryl) ketones being detectable. 相似文献
99.
N. K. Gusarova S. F. Malysheva N. A. Belogorlova V. A. Kuimov I. A. Ushakov B. A. Trofimov 《Russian Chemical Bulletin》2009,58(1):234-237
Secondary phosphine sulfides react with acetylene and methylacetylene in the system KOH—DMSO (50 °C, 2—3 h) to form the corresponding
tertiary bis-phosphine sulfides in high yield (up to 97%). Specific features of the NMR spectra (1H, 13C, and 31P) of compounds obtained are discussed. 相似文献
100.
I.?A.?KirovskayaEmail author E.?V.?Mironova O.?V.?Ushakov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2018,12(1):75-79
Using the methods of hydrolytic adsorption, mechanochemistry, and nonaqueous conductometric titration, the acid–base properties of the surfaces of binary semiconductors and solid solutions of the ZnSe?CdS system are studied. The nature of acid sites, and the extent, character, and mechanism of the surface (absorption) interaction are established. The interrelationships in the changes of the acid–base and bulk physical properties upon changing the chemical composition are determined, which make it possible to draw conclusions that are fundamentally important in scientific and practical aspects. 相似文献