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151.
152.
A. A. Kovalenko 《Fluid Dynamics》1995,30(4):555-562
A method of solving the boundary layer equations is developed taking into account the strong interaction between the boundary layer and the outer hypersonic inviscid flow. The method is aimed at solving problems whose salient feature is the possible upstream propagation of disturbances over distances comparable with the body length. The procedure for fitting a self-consistent contour of the effective body using an artificially formulated boundary value problem for an ordinary second-order differential equation, which lies at the basis of the method, is considered in detail. The method is applied to the problem of flow around a flat plate with roughness in the form of an embankment or a trench; the calculated results are presented.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 81–89, July–August, 1995. 相似文献
153.
Numerical simulation of radio energy transfer in the ionospheric layer with random small-scale irregularities for the case of a point ground-based source and total reflection has been carried out using a specially designed algorithm based on Monte Carlo method ideas. The model demonstrates a redistribution of the reflected radiation power at the Earth's surface caused by multiple scattering. The data obtained can serve as confirmation of the effect of the anomalous attenuation of the signal power in the vicinity of the sounder. This result is in agreement with a more rigorous theory of the anomalous attenuation effect based on the solution of the radiative transfer equation. 相似文献
154.
Radiophysics and Quantum Electronics - 相似文献
155.
156.
Prof. Dr. Oleksandr O. Grygorenko Prof. Dr. Rostyslav D. Lampeka Prof. Dr. Valentyn A. Chebanov Prof. Dr. Maksym V. Kovalenko Prof. Dr. Stefan Wuttke 《Chemical record (New York, N.Y.)》2024,24(2):e202400008
In this special issue, we highlight recent advances in chemical research by scientists in Ukraine, as well as by their compatriots and collaborators outside the country. Besides spotlighting their contributions, we see our task in fostering global partnerships and multi-, inter-, and trans-disciplinary collaborations, including much-needed co-funded projects and initiatives. The three decades of the renewed Ukraine independence have seen rather limited integration of Ukrainian (chemical) science into global research communities.[1] At the same time, the recent surge of collaborative science initiatives between European Union (EU) and Ukraine echoes the unfolding steps towards Ukraine's full research participation to the Horizon Europe Program. This recently implemented step opens enormous possibilities for Ukrainian researchers to apply for diverse EU research grants. Moreover, a number of journal special issues and collections were launched to highlight Ukrainian chemistry (i. e., by Chemistry of Heterocyclic Compounds[2] and ChemistrySelect[3]). Other scientific initiatives include ‘European Chemistry School for Ukrainians’[4] and ‘Kharkiv Chemical Seminar’[5] as voluntary projects aimed at engaging Ukrainian scientists into European and international chemical research. 相似文献
157.
Taisiya S. Sukhikh Evgeny Yu. Filatov Alexey A. Ryadun Konstantin A. Kovalenko Andrei S. Potapov 《Molecules (Basel, Switzerland)》2022,27(19)
A three-component reaction between the 1,4-benzenedicarboxylic (terephthalic) acid (H2bdc), bis(1,2,4-triazol-1-yl)methane (btrm) and zinc nitrate was studied, and three new coordination polymers were isolated by a careful selection of the reaction conditions. Coordination polymers {[Zn3(DMF)(btrm)(bdc)3]·nDMF}∞ and {[Zn3(btrm)(bdc)3]·nDMF}∞ containing trinuclear {Zn3(bdc)3} secondary building units are joined by btrm auxiliary linkers into three-dimensional metal–organic frameworks. The coordination polymer {[Zn(bdc)(btrm)]∙nDMF}∞ consists of Zn2+ cations joined by bdc2− and btrm linkers into a two-fold interpenetrated network. Upon activation, MOF [Zn3(btrm)(bdc)3]∞ demonstrated CO2/N2 adsorption selectivity with an ideal adsorbed solution theory (IAST) factor of 21. All three MOF demonstrated photoluminescence with a maximum near 435–440 nm upon excitation at 330 nm. 相似文献
158.
V. N. Karpinskii N. G. Kondrat’ev A. L. Osipenkov V. G. Karavaev N. A. Filippov G. V. Trubnikov A. D. Kovalenko A. O. Sidorin A. V. Butenko V. I. Volkov B. V. Vasilishin A. E. Kirichenko S. V. Romanov 《Physics of Particles and Nuclei Letters》2010,7(7):517-521
One of the trends of Nuclotron development lies in modifying the power supply system and upgrading the energy evacuation system of structural magnets in order to provide reliable durable operation of the synchrotron at a dipole magnet field level of 2 T. This is necessary for Nuclotron operation as part of the injection chain of the heavy-ion NICA collider under design at JINR and for the current program of physical studies. The principles of construction and specific features of the existing system based on a separate power supply of structural dipole and quadrupole magnetic elements are considered. The main provisions of the upgrade of the power supply system, structural and schematic diagrams, control schemes, and energy evacuation switch schemes from superconducting elements are presented. 相似文献
159.
Valentina Georgievna Ponomareva Elena Sergeevna Shutova Konstantin Aleksandrovich Kovalenko Vladimir Petrovich Fedin 《Molecules (Basel, Switzerland)》2022,27(23)
New (1−x)CsH2PO4–xUiO-66 electrolytes with high proton conductivity and thermal stability at 230–250 °C were developed. The phase composition and proton conductivity of nanocomposites (x = 0–0.15) were investigated in detail. As shown, the UiO-66 matrix is thermally and chemically suitable for creating composites based on CsH2PO4. The CsH2PO4 crystal structure remains, but the degree of salt crystallinity changes in nanocomposites. As a result of interface interaction, dispersion, and partial salt amorphization, the proton conductivity of the composite increases by two orders of magnitude in the low-temperature range (up to 200 °C), depending on the UiO-66 fraction, and goes through a maximum. At higher temperatures, up to 250 °C, the conductivity of nanocomposites is close to the superprotonic values of the original salt at low UiO-66 values; then, it decreases linearly within one order of magnitude and drops sharply at x > 0.07. The stability of CsH2PO4-UiO-66 composites with high proton conductivity was shown. This creates prospects for their use as proton membranes in electrochemical devices. 相似文献
160.
Agapov N. Averichev S. Donyagin A. Eliseeva I. Karpunina I. Khodzhibagiyan H. Kovalenko A. Kuznetsov G. Kuzichev V. Moritz G. Muehle C. Nikitaev P. Starikov A. 《Applied Superconductivity, IEEE Transactions on》2002,12(1):116-119
Two new prototype dipole magnets for the proposed new fast cycling (f=1 Hz) synchrotron at GSI in Darmstadt have been designed, fabricated and tested. The magnets are based on a window frame iron yoke cooled by liquid nitrogen and a superconducting winding made from a hollow NbTi composite superconductor cable cooled with forced two-phase helium flow at T=4.5 K. The cold mass of the magnet is separated from the yoke by a small vacuum gap of 0.75 mm to 2.5 mm. A decrease of ac power losses by a factor of 2.3 in comparison with a standard Nuclotron dipole is obtained. The design features of two prototype dipoles as well as the test results are presented. 相似文献