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411.
The paper discusses the applicability of cold gaseous nitrogen as a model working fluid in testing the hydrogen pump seals for power plants by three-dimensional modeling. 相似文献
412.
This paper considers the axisymmetric transverse vibrations of aircraft nonuniform structural elements that are introduced by a thermal shock. Analytical solutions have been obtained and their numerical analysis has been performed. 相似文献
413.
V.D. Kuznetsov I.I. Sobelman I.A. Zhitnik S.V. Kuzin Yu.D. Kotov Yu.E. Charikov S.N. Kuznetsov E.P. Mazets A.A. Nusinov A.M. Pankov J. Sylwester 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The CORONAS-F mission experiments and results have been reviewed. The observations with the DIFOS multi-channel photometer in a broad spectral range from 350 to 1500 nm have revealed the dependence of the relative amplitudes of p-modes of the global solar oscillations on the wavelength that agrees perfectly well with the earlier data obtained in a narrower spectral ranges. The SPIRIT EUV observations have enabled the study of various manifestations of solar activity and high-temperature events on the Sun. The data from the X-ray spectrometer RESIK, gamma spectrometer HELICON, flare spectrometer IRIS, amplitude–temporal spectrometer AVS-F, and X-ray spectrometer RPS-1 have been used to analyze the X- and gamma-ray emission from solar flares and for diagnostics of the flaring plasma. The absolute and relative content of various elements (such as potassium, argon, and sulfur) of solar plasma in flares has been determined for the first time with the X-ray spectrometer RESIK. The Solar Cosmic Ray Complex monitored the solar flare effects in the Earth’s environment. The UV emission variations recorded during solar flares in the vicinity of the 120-nm wavelength have been analyzed and the amplitude of relative variations has been determined. 相似文献
414.
A. V. Bogomolov I. N. Myagkova V. V. Kalegaev S. I. Svertilov V. V. Bogomolov M. I. Panasyuk V. L. Petrov I. V. Yashin 《Cosmic Research》2017,55(6):446-456
The work is devoted to observations of sharp growths of magnetospheric electron fluxes in the vicinity of the polar boundary of the outer radiation belt of the Earth according to the data of measurements on the Vernov and Lomonosov satellites. This precipitation was observed at the high-latitude boundary of the outer radiation belt toward the equator from the isotropization boundary, and can be caused by scattering waves of various physical natures, including electromagnetic and electrostatic waves. 相似文献
415.
This paper considers issues of designing a gas-turbine engine in the helicopter system at the early design stages. The optimum and rational values of engine working process parameters at different flight speeds of the flight vehicle (FV) are analyzed. Several characteristics of mathematical models (MM) that form the helicopter–engine system, are described. 相似文献
416.
G. Ghirlanda L. NavaG. Ghisellini 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Short and long GRBs are thought to be two distinct classes based on their different duration and spectrum. Through the spectral analysis of two similarly selected samples of BATSE short and long GRBs, we show that short GRBs are harder than long events, confirming what found from the comparison of their hardness ratio. However, this spectral diversity seems to be due to a harder low energy spectral component of short GRBs, rather than a (slightly higher) peak energy. Interestingly short GRBs have a spectrum which is similar to the spectrum of the emission of the first 1–2 s of long events. We find evidence that short GRBs are inconsistent with the Epeak–Eiso correlation defined by long bursts while they follow the same Epeak–Liso correlation of long GRBs. These results, coupled to the similar variability timescale of short events and the first seconds of long ones, suggest that a common (or similar) dissipation mechanism could operate in both classes. The difference in the duration would then be due mainly to the central engine lifetime. 相似文献
417.
B. Rizk C. Drouet dAubigny C.W. Hergenrother B.J. Bos D.R. Golish R. Malhotra D.S. Lauretta J. Butt J. Patel M. Fitzgibbon C. May E.B. Bierhaus S. Freund M. Fisher S. Cambioni C.A. Bennett S.S. Balram-Knutson K. Harshman M. Moreau 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(1):672-691
We analyzed high-angular rate streaks first recorded by OSIRIS-REx’s MapCam during a 2017 search for Earth Trojan asteroids. We interpret them as water-ice particles that translated across the imager’s field of view, originating from the spacecraft itself. Their translation velocities approximated 0.1–1?m/s based on reasonable conclusions about their range. Pursuing several lines of investigation to seek a coherent hypothesis, we conclude that the episodic releases of the water ice particles are associated with spacecraft attitudes that resulted in solar illumination of previously shadowed regions. This correlation suggests that the OSIRIS-REx spacecraft itself possesses micro-climatic zones consisting of hot regions and cold traps that may temporarily potentially pass volatiles back and forth before losing most of them. 相似文献
418.
419.
In this paper, we consider an example of estimating and comparing the efficiency of different concepts for a high-altitude unmanned aerial vehicle (UAV) under diversity of efficiency criteria. 相似文献
420.
B. A. Antuf’ev 《Russian Aeronautics (Iz VUZ)》2016,59(3):303-307
This study proposes an approximate solution to a contact problem of dynamic deformation of a cyclically symmetrical discretely ring-stiffened cylindrical shell, the side surface of which is subjected to an evenly distributed inertia live load. The solution of the problem assumes the quasistatic mode of deformation of the structure. Several critical velocities of the live load have been found. A number of examples are presented. 相似文献