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991.
992.
A. G. Merzhanov A. S. Rogachev E. N. Rumanov V. N. Sanin A. E. Sytchev V. A. Shcherbakov V. I. Yukhvid 《Cosmic Research》2001,39(2):210-223
The self-propagating high-temperature synthesis was applied for the production of foam materials under the conditions of microgravity aboard the Mirstation. The materials obtained have a porous bimodal structure. The results of space experiments predicted using the interpolation method are checked. An unpredicted phase separation of the combustion products is discovered. The autowave combustion of suspended nickel-clad aluminum solids is observed for the first time. The combustion products were found to have a frame structure. 相似文献
993.
T V Michurina E I Domaratskaya T M Nikonova N G Khrushchov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,17(6-7):295-298
Ribbed newts were used for studying the effect of space flight on board of the biosatellite (Cosmos-2229) on blood and clonogenic hemopoietic cells. In blood of newts of the flight group, the relative proportion of neutrophils increased, whereas that of lymphocytes and eosinophils decreased. Space flight did not result in loss of the ability of newt blood cells to incorporate H3-thymidine. Analysis of clonogenic hemopoietic cells was performed using the method of hemopoietic colony formation on cellulose acetate membranes implanted into the peritoneal cavity of irradiated newts. To analyze reconstitution of hemopoiesis after irradiation donor hemopoietic cells from flight or control newts were transplanted into irradiated newts whose hemopoietic organs were investigated. The newt can be considered an adequate model for studying hemopoiesis under the conditions of the space flight. 相似文献
994.
Wohlmuth R. Plettemeier D. Edenhofer P. Bird M.K. Efimov A.I. Andreev V.E. Samoznaev L.N. Chashei I.V. 《Space Science Reviews》2001,97(1-4):9-12
Temporal power spectra have been computed from recordings of the downlink frequency fluctuations of the Galileo and Ulysses radio signals during their solar conjunctions. Both the equatorial streamer belt and the polar coronal holes were investigated
over a range of ray path solar offset distances from 4 to 80 R⊙. By combining gapless data from successive tracking passes, Doppler scintillation power spectra could be computed down to
extremely low frequencies. Some spectra feature a low-frequency turnover at frequencies around 0.1 mHz that could be interpreted
as an outer scale of density turbulence in the coronal plasma.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
995.
The interaction of Phobos with the solar wind is considered both theoretically and using the experimental data of the FGMM magnetometer that were obtained in the course of the Phobos-2mission. It is demonstrated that the ions serving as a source of excitation of magnetosonic waves can be accumulated around Phobos. Examination of the magnetometer data has shown that the observed effects of a local decrease of the magnetic field near the Phobos orbit correspond to magnetosonic waves. Observation of these effects depends on the geometry of an experiment. 相似文献
996.
Evlanov E. N. Zubkov B. V. Nenarokov D. F. Linkin V. M. Zavjalov M. A. Tyuryukanov P. M. 《Cosmic Research》2001,39(5):453-458
A gas-discharge anemometer is designed for investigating the gas-flow dynamics in wind tunnels, and in experimental and space meteorology. The anemometer allows one to measure simultaneously the magnitude and direction of the gas-flow velocity vector and the gas pressure in the flow. The instrument consists of a gas-discharge chamber, an analyzer of scattered ions, a power supply unit, and a measuring unit. The anemometer weight does not exceed 0.1 kg, and the power consumption does not exceed 0.2 W. The instrument was put through preliminary tests in a wind tunnel that simulated, in particular, the conditions in the boundary layer of the Martian atmosphere and produced a directed gas (air or CO2) flow whose velocity could be varied from 0.5 to 50 m/s at pressures from 0.3 to 1.3 kPa and temperatures from –120 to +20°C. The anemometer sensitivity is no worse than 100 mV/(m/s). The method of calculating the gas-flow velocity on the basis of the measured ion-current distributions is developed. 相似文献
997.
Synthetic Aperture Radar (SAR) is an airborne (or spaceborne) radar mapping technique for generating high resolution maps of surface target areas including terrain. High resolution is achieved by coherently combining the returns from a number of radar transmissions. The resolution of the images is determined by the parameters of the emissions, with more data giving greater resolution. A requirement of the Microwave Radar Division's SAR radar is to provide classification of targets. This paper presents a technique for enhancing slant range resolution in SAR images by dithering the carrier centre frequency of the transmitted signal. The procedure controls the radar waveforms so they will optimally perform the classification function, rather than provide an image of best quality. It is shown that a Knowledge-Based engineering approach to determining the waveform of the radar gives considerably improved performance as a classifier of targets (of large radar cross-section), even though the corresponding image is degraded 相似文献
998.
Committee on Space Policy H.Guyford Stever Laurence J. Adams Consultant Retired President William A. Anders Senior Executive Vice President Arden L. Bement Jr Vice President Joseph V. Charyk Chairman of the Board Retired Chairman CEO Richard N. Cooper Robert S. Cooper President Edward E. David Jr President John M. Logsdon Director Jeremiah P. Ostriker Director Samuel C. Phillips Retired General Elmer B. Staats Edward C. Stone Jr Vice President 《Space Policy》1989,5(3)
999.
1000.
Kabrisky M. Rogers S.K. Bashir N.A. 《Aerospace and Electronic Systems Magazine, IEEE》1989,4(9):39-43
A system has been developed to enhance the quality of mutilated speech. A standard spectrogram analysis of the damaged speech is performed. The speech is then resynthesized as a sum of computer-generated sinusoids whose amplitudes and phases are derived partly from the given mutilated speech signal and partly from rules based on known properties of normal speech. The sinusoids selected are only approximate harmonics of the glottal pitch and are selected by a nonlinear, noncausal set of rules to reduce the nonspeech components in the synthesized speech output. The system has been shown to increase the quality of the mutilated speech appreciably 相似文献