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41.
42.
Boris A. Trofimov Tatyana E. Glotova Marina Yu. Dvorko Igor’ A. Ushakov Elena Yu. Schmidt Al’bina I. Mikhaleva 《Tetrahedron》2010,66(38):7527-3421
Triphenylphosphine catalyzes the regio- and stereospecific addition of ketoximes to acylacetylenes, whereas classical conditions using acetylene (KOH/DMSO, 70 °C) are unsuitable for this purpose. The reaction proceeds under mild conditions (CH2Cl2, rt, 7 h) to afford (E)-(O)-2-(acyl)vinylketoximes (92-98% stereoselectivity) in a yield of up to 85%. The (E)-adducts obtained are energetically less favorable than the corresponding (Z)-isomers and are gradually enriched with (Z)-isomers, thus indicating the kinetic control of (E)-stereoselectivity of the reaction. 相似文献
43.
Spike train regularity of the noisy neural auditory system model under the influence of two sinusoidal signals with different frequencies is investigated. For the increasing ratio m/n of the input signal frequencies (m, n are natural numbers) the linear growth of the regularity is found at the fixed difference (m - n). It is shown that the spike train regularity in the model is high for harmonious chords of input tones and low for dissonant ones. 相似文献
44.
Toriyama T Nakao A Yamaki Y Nakao H Murakami Y Hasegawa K Isobe M Ueda Y Ushakov AV Khomskii DI Streltsov SV Konishi T Ohta Y 《Physical review letters》2011,107(26):266402
Synchrotron x-ray diffraction experiment shows that the metal-insulator transition occurring in a ferromagnetic state of a hollandite K(2)Cr(8)O(16) is accompanied by a structural distortion from the tetragonal I4/m to monoclinic P112(1)/a phase with a √2×√2×1 supercell. Detailed electronic structure calculations demonstrate that the metal-insulator transition is caused by a Peierls instability in the quasi-one-dimensional column structure made of four coupled Cr-O chains running in the c direction, leading to the formation of tetramers of Cr ions below the transition temperature. This provides a rare example of the Peierls transition of fully spin-polarized electron systems. 相似文献
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46.
A. V. Ushakov V. G. Ushakov 《Moscow University Computational Mathematics and Cybernetics》2012,36(1):28-35
Joint generating functions of queue length are obtained for a single-channel absolute priority system with restarting service of interrupted units and recurrent input flow with hyperexponential distribution of intervals between arrivals. 相似文献
47.
V. N. Ushakov 《Differential Equations》2011,47(7):1046-1058
We study the stability property in a game-theoretic problem on the approach of a conflict control system to an objective set at a fixed time. 相似文献
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Fedorov P. P. Ushakov S. N. Uslamina M. A. Chernova E. V. Kuznetsov S. V. Voronov V. V. Düvel A. Heitjans P. Pynenkov A. A. Nishchev K. N. Osiko V. V. 《Crystallography Reports》2018,63(5):837-843
Crystallography Reports - Proceeding from the phase diagram of the CaF2–SrF2 system, the stability of crystal–melt interface of solid solution against constitutional supercooling has... 相似文献
50.
A. V. Ushakov I. V. Karpov A. A. Lepeshev M. I. Petrov L. Yu. Fedorov 《JETP Letters》2014,99(2):99-103
In this work, the effect of ZrO2 nanoparticles prepared in a low-pressure arc discharge plasma on magnetic flux pinning of granular YBa2Cu3O7 ? y /nanoZrO2 composites has been studied. It has been shown that the ZrO2 nanoparticles do not change the superconducting transition and the microstructure of superconductors. At a temperature of 5 K, the addition of 0.5 and 1 wt % of ZrO2 nanoparticles may lead to the additional effect of magnetic flux pinning and the increase in the critical current density J c. The J c value for composites with 1 wt % is two times larger than that for the reference sample. The fishtail effect is observed for YBa2Cu3O7 ? y /nanoZrO2 composites at the temperatures of 20 and 50 K. The problems associated with the additional effect of magnetic flux pinning of granular YBa2Cu3O7 ? y /nanoZrO2 composites and the appearance of the fishtail effect have been discussed. 相似文献