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101.
I. V. Karpov A. V. Ushakov A. A. Lepeshev L. Yu. Fedorov E. A. Dorozhkina O. N. Karpova A. A. Shaikhadinov V. G. Demin 《Technical Physics》2018,63(2):230-234
A device for modifying the granular high-temperature superconducting ceramics in the plasma of a low-pressure arc discharge has been considered. The particular features of the design and operational principle of this device have been described. The device made it possible to combine the synthesis of that play a role of additional pinning centers and simultaneous deposition of these nanoparticles on microgranules in a single processing cycle. The experimental results on the effect of additional pinning centers on an increase in the critical current thanks to the formation of self-assembled structures in the form of whiskers have been considered. 相似文献
102.
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
103.
V. N. Ushakov P. D. Lebedev A. R. Matviychuk A. G. Malev 《Proceedings of the Steklov Institute of Mathematics》2012,277(1):266-277
This paper contributes to the theory of differential games. A game problem of bringing a conflict-controlled system to a compact target set is analyzed. Sets in the position space that terminate on the target set and are not stable bridges are considered. The notion of stability defect of these sets is examined. It is demonstrated how the notion of stability defect can be used to construct sets with relatively good geometry that are at the same time convenient for the first player to play the game successfully. 相似文献
104.
An investigation is undertaken into the variations observed in the cracking resistance, the plasticity, and the structure of an 82K3KhSR metallic glass upon annealing. A method of evaluating the mechanical properties and the structural state of metallic glasses is proposed. This method is based on the indentation of the metallic glass deposited onto a substrate prepared from a polyester material and a metal. The critical annealing temperature that corresponds to drastic changes in the mechanical properties of the metallic glass is determined. It is found that dependences of the cracking resistance of metallic glasses on the indenter load exhibit a linear behavior at annealing temperatures above the critical point. An exponential decrease in the cracking resistance upon indentation is observed with an increase in the annealing temperature of metallic glasses. 相似文献
105.
Maxim D. Gotsko Ivan V. Saliy Lyubov N. Sobenina Igor A. Ushakov Boris A. Trofimov 《Tetrahedron letters》2019,60(40):151126
Functionalized pyrrole-pyrone ensembles have been synthesized in up to 87% yields by KOH/MeCN [4+2]-cyclization of available acylethynylpyrroles with methylene active esters. The synthesized compounds, due to their potential rich chemistry, are rewarding building blocks for novel pyrrole-integrated complex molecules and promising precursors of medicine targeted compounds. 相似文献
106.
Russian Chemical Bulletin - 相似文献
107.
Tarasova O. A. Brandsma L. Nedolya N. A. Afonin A. V. Ushakov I. A. Klyba L. V. 《Russian Journal of Organic Chemistry》2003,39(10):1451-1457
The reaction of 1,3-dilithio-3-phenylpropyne with methyl isothiocyanate in THF-hexane at -90 to -55°C, followed by successive treatment of intermediate product with a donor of protons, superbase, and alkyl halide, yields isomeric iminocyclobutenes and iminothietanes in addition to the expected aminothiophene. The ratio of the products depends on the amount and nature of proton donor (MeOH, t-BuOH), base (MeONa, t-BuOM, M = Li, Na, K; t-AmOK), co-solvent (DMSO, HMPA), and alkyl halide (MeI, EtI, BuBr). The system t-BuOH(MeOH)-t-BuOK-DMSO is the most favorable for the formation of the corresponding iminocyclobutene. 相似文献
108.
109.
110.
V. N. Ushakov Ya. A. Latushkin 《Proceedings of the Steklov Institute of Mathematics》2008,262(1):244-262
We consider a finite-dimensional conflict-controlled system whose behavior on a finite time interval is described by a vector differential equation. We analyze two game problems of approach in the phase space. In both problems the same terminal set is considered: in the first case, one should guarantee that the phase vector of the system reaches the terminal set at the final instant of time; in the second case, the phase vector should reach the terminal set no later than the final time instant. It is natural to assume that the construction of a solution to the first problem is much simpler than the construction of a solution to the second problem; this fact is confirmed by available experience. The paper is devoted to finding conditions on the system and the terminal set under which the solutions to the above problems coincide. Using these conditions, one can replace the solution of the second problem by the simpler solution of the first problem. 相似文献