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941.
942.
A. L. Tukmakov V. G. Tonkonog A. G. Kochenkov S. A. Kusyumov 《Russian Aeronautics (Iz VUZ)》2011,54(4):402-411
A physical and mathematical model of a boiling-up fluid flow in the variable crosssection channels is proposed. The numerical
model is based on the solution of the Navier-Stokes nonstationary equations for compressible fluid by the implicit finite-difference
method. We present the results of the numerical modeling for two-phase flow characteristics at the initial stage of the evaporation
process and the steady-state quasistationary flow of a two-phase medium. 相似文献
943.
S. A. Mikhailov L. V. Korotkov S. A. Alimov D. V. Nedel’ko 《Russian Aeronautics (Iz VUZ)》2011,54(3):247-253
A technique is suggested for calculating the helicopter spatial motion and the stress-strain state of a skid landing gear
in the course of landing with regard for the second landing impact; geometric, material and design nonlinearity of undercarriage
springs deformation is taken into account. The comparison between the analysis results and experimental data is presented. 相似文献
944.
945.
O.W. Lennartsson H.L. Collin W.K. Peterson E.G. Shelley 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2000,25(12):2417-2420
Ion composition data from the first 22 months of operation of the Polar/TIMAS instrument, covering the 15-eV/e to 33-keV/e energy range, have been surveyed to determine the typical abundance, at solar minimum, of N2+, NO+ and O2+ ions in the auroral ion outflow, as compared to that of the better known O+ ions. The results indicate that molecular ions have roughly the same energy distribution as the O+ ions, with maximum differential flux occurring below 400 eV, but are far less abundant, by two orders of magnitude. The molecular ions also differ from the O+ ions in that they seem more specifically associated with enhanced geomagnetic activity. 相似文献
946.
The investigation of stability and precision of the previously proposed implicit scheme of direct integration for the finite
element equations of motion is presented. The scheme parameter values that ensure its unconditional stability in the nonlinear
problems are determined and comparison with existing procedures is given. 相似文献
947.
E.L. Afraimovich E.I. AstafyevaV.V. Demyanov I.F. Gamayunov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Degradation of transionospheric radio signals and operation failures during ionospheric disturbances constitute a crucial factor of space weather influence on radio engineering satellite systems performance. We found that during the main phase of strong magnetic storms in 2000–2003 when the auroral oval expands into mid-latitudes, its southern boundary develops a region with intense small-scale electron density irregularities. Such irregularities may cause strong amplitude scintillations of GPS signals at both GPS operating frequencies. The another consequence of it was significant random GPS signal phase fluctuations, breaking-down of signal tracking, and sharp increasing of GPS positioning errors as a result. 相似文献
948.
O. T. Demkiv E. L. Kordyum O. R. Kardash O. Ya. Khorkavtsiv 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1999,23(12):1999-2004
The gravitropism of protonemata of Pohlia nutans is described and compared with that of other mosses. In darkness, protonemata showed negative gravitropism. Under uniform illumination they grew radially over the substrate surface, whereas unilateral illumination induced positive phototropic growth. Gravitropism was coupled with starch synthesis and amyloplast formation. Protonematal gravitropic growth is more variable than the strict negative gravitropism of Ceratodon chloronema. 相似文献
949.
950.
Avionics Systems Validation Test Environments 总被引:1,自引:0,他引:1