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1.
Hugo M. Campos Vladislav V. Kravchenko 《Mathematical Methods in the Applied Sciences》2020,43(16):9448-9454
The paper extends some well-known results for analytic functions onto solutions of the Vekua equation regarding the existence and construction of the Bergman kernel and of the corresponding Bergman projection operator. 相似文献
2.
A. G. Burlakova S. E. Kravchenko I. A. Domashnev A. A. Vinokurov S. E. Nadkhina L. S. Volkova S. P. Shilkin 《Russian Journal of General Chemistry》2017,87(5):906-911
Products of the zirconium powder reaction with amorphous boron in a Na2B4O7 ionic melt at 650–850°C and those of the ZrCl4 reaction with NaBH4 at 300–725°C have been studied by means of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry, and elemental analysis. At temperature ≥750°C, single-phase ZrB2 with the particle size of 60–80 nm is formed in a Na2B4O7 ionic melt, whereas the ZrB2 powder obtained via the reaction of ZrCl4 with NaBH4 at temperature ≥575°C consists of particles differing in the shape, some of which are close to spherical with diameter of 10–35 nm. 相似文献
3.
Svitlana V. Shishkina Irina S. Konovalova Sergiy M. Kovalenko Dmitriy V. Kravchenko Natalya D. Bunyatyan 《Acta Crystallographica. Section C, Structural Chemistry》2021,77(1):40-48
Being a close analogue of amflutizole, methyl 4‐amino‐3‐phenylisothiazole‐5‐carboxylate (C11H10N2O2S) was assumed to be capable of forming polymorphic structures. Noncentrosymmetric and centrosymmetric polymorphs have been obtained by crystallization from a series of more volatile solvents and from denser tetrachloromethane, respectively. Identical conformations of the molecule are found in both structures. The two polymorphs differ mainly in the intermolecular interactions formed by the amino group and in the type of stacking interactions between the π‐systems. The most effective method for revealing packing motifs in structures with intermolecular interactions of different types (hydrogen bonding, stacking, dispersion, etc.) is to study the pairwise interaction energies using quantum chemical calculations. Molecules form a column as the primary basic structural motif due to stacking interactions in both polymorphic structures under study. The character of a column (straight or zigzag) is determined by the orientations of the stacked molecules (in a `head‐to‐head' or `head‐to‐tail' manner). Columns bound by intermolecular N—H…O and N—H…N hydrogen bonds form a double column as the main structural motif in the noncentrosymmetric structure. Double columns in the noncentrosymmetric structure and columns in the centrosymmetric structure interact strongly within the ab crystallographic plane, forming a layer as a secondary basic structural motif. The noncentrosymmetric structure has a lower density and a lower (by 0.59 kJ mol?1) lattice energy, calculated using periodic calculations, compared to the centrosymmetric structure. 相似文献
4.
5.
M. N. Dmitriev N. M. Dmitriev V. V. Kadet M. N. Kravchenko S. G. Rassokhin 《Fluid Dynamics》2004,39(4):589-593
The results of an experimental determination of the relative phase permeabilities during flow of two immiscible fluids in stratified sandstone with transversally isotropic characteristics are presented. The measurements were performed on samples oriented in three directions: along, perpendicular to and at an angle of 45° to the stratification plane. An approximate solution of the problem of steady two-phase flow toward a finite gallery in an anisotropic porous medium for arbitrary relative orientation of the gallery and the principal axes of the absolute permeability tensor is given. This solution was tested against the experimental results. The good agreement between the theoretical and experimental results makes it possible to recommend for engineering calculations both the relations between the absolute and phase permeabilities for transversally isotropic and orthotropic porous media and the approximate solution obtained. 相似文献
6.
Achasov M. N. Barnyakov A. Yu. Barnyakov M. Yu. Beloborodov K. I. Berdyugin A. V. Bogdanchikov A. G. Botov A. A. Buzykaev A. R. Golubev V. B. Dimova T. V. Druzhinin V. P. Kardapoltsev L. V. Kovrizhin D. P. Korol A. A. Kravchenko E. A. Kupich A. S. Martin K. A. Melnikova N. A. Obrazovsky A. E. Onuchin A. P. Pakhtusova E. V. Pugachev K. V. Serednyakov S. I. Silagadze Z. K. Surin I. K. Usov Yu. V. Kharlamov A. G. Shtol D. A. 《Physics of Atomic Nuclei》2021,84(1):59-62
Physics of Atomic Nuclei - In an experiment with the SND detector at the VEPP-2000 $$e^{+}e^{-}$$ collider, the cross sections for the processes $$e^{+}e^{-}\to K^{+}K^{-}\pi^{0}$$ and... 相似文献
7.
8.
Kravchenko S. E. Burlakova A. G. Domashnev I. A. Vinokurov A. A. Shilkin S. P. 《Russian Journal of General Chemistry》2019,89(4):641-646
Russian Journal of General Chemistry - X-ray diffraction, scanning electron microscopic, and X-ray photoelectron spectroscopic examinations, as well as energy dispersive X-ray and elemental... 相似文献
9.
Daria V. Chernysheva Victor A. Klushin Alexander F. Zubenko Lyudmila S. Pudova Oleg A. Kravchenko Victor M. Chernyshev Nina V. Smirnova 《Mendeleev Communications》2018,28(4):431-433
The Pt/C catalysts with various Pt content (5-30 wt%) synthesized via electrochemical pulse alternating current technique have been evaluated for the base-free aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. The higher Pt content in the catalyst (30 wt%) provides the product yield up to 65% upon performing the process in concentrated (~0.1 M) aqueous solutions of the substrate. 相似文献
10.
Davidenko N. A. Davidenko I. I. Mokrinskaya E. V. Studzinskiy S. L. Kravchenko V. V. 《Journal of Applied Spectroscopy》2021,88(2):382-388
Journal of Applied Spectroscopy - New photosensitive polymeric film composites based on oligo-N-glycidylcarbazole oligomer with azobenzene dyes as additives (azobenzene derivatives with a glycidyl... 相似文献