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V. V. Semenov I. E. Ivanov I. A. Kryukov A. S. Rochev 《Russian Aeronautics (Iz VUZ)》2007,50(4):385-389
The results of numerical simulation of a flow in the complex-shaped channels and experimental investigation of characteristics of a gasodynamic igniter equipped with a plug nozzle are presented. It is shown that the igniter characteristics are significantly improved as a result of replacing an acoustic nozzle by an annular one. 相似文献
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U Micke M Sch?fer A Anton G Horneck H Bücker 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1992,12(2-3):59-63
DNA damage induced by heavy ions in bacterial cells and bacteriophages such as Bacillus subtilis, E. coli and Bacteriophage T1 were investigated by analyzing the double strand breaks in the chromosomal DNA. This kind of lesion is considered as one of the main reasons for lethal events. To analyze double strand breaks in long molecules of DNA--up to some Mbp in length--the technique of pulse field agarose gel electrophoresis has been used. This allows the detection of one double strand break per genome. Cell lysis and DNA isolation were performed in small agarose blocks directly. This procedure secured minimum DNA destruction by shearing forces. After running a gel, the DNA was stained with ethidium bromide. The light intensity of ethidium bromide fluorescence for both the outcoming (running) DNA and the remaining intact DNA were measured by scanning. The mean number of double strand breaks was calculated by determining the quotient of these intensities. Strand break induction after heavy ion and X-ray irradiation was compared. 相似文献
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Boris A. Ivanov 《Space Science Reviews》2001,96(1-4):87-104
This article presents a method to adapt the lunar production function, i.e. the frequency of impacts with a given size of a formed crater as discussed by Neukum et al. (2001), to Mars. This requires to study the nature of crater-forming projectiles, the impact rate difference, and the scaling laws for the impact crater formation. These old-standing questions are reviewed, and examples for the re-calculation of the production function from the moon to Mars are given. 相似文献
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Cosmic Research - A technique is presented for reconstructing the height profiles of the volume emission rate and estimating the crosscut dimensions of rayed structures in auroras from the data of... 相似文献
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Zh.?V.?DashkevichEmail author V.?E.?Ivanov T.?I.?Sergienko B.?V.?Kozelov 《Cosmic Research》2017,55(2):88-100
A physicochemical model of excited polar ionosphere has been presented. The model makes it possible to calculate vertical profiles of concentrations of the following excited and ionized constituents: O2 +, N2 +, O+(4S), O+(2D), O+(2P), O(1D), O(1S), N(4S), N(2D), N(2P), NO, NO+, N+, N2(A3Σu +), N2(B3Пg), N2(W3Δu), and N2(B′3Σu -) and the electron concentration during electron precipitations. The energy spectrum of the electrons at the upper boundary of the ionosphere and concentrations of neutral constituents are the input parameters of the model. A model has been compiled based on available publications and includes 56 physicochemical reactions that influence concentrations of the aforementioned constituents in the polar ionosphere. The method of calculating vertical profiles of the excitation rates of atmospheric gases and proper allowance for the electron-vibrational kinetics in the processes of exciting the triplet states of N2 are specific features of the presented model. The ionospheric model has been approbated using the results of the coordinated rocket–satellite experiment. The agreement between the modeling results and experimental data best for the time being is achieved. 相似文献
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Peter Plötner Markus Czupalla Anton Zhukov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
The Virtual Habitat (V-HAB), is a Life Support System (LSS) simulation, created to perform dynamic simulation of LSS’s for future human spaceflight missions. It allows the testing of LSS robustness by means of computer simulations, e.g. of worst case scenarios. 相似文献
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E.N. Grigoryan H.J. Anton V.A. Poplinskaya K.S. Aleinikova E.I. Domaratskaya Y.P. Novikova E. Almeida 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
The effects of real and simulated microgravity on the eye tissue regeneration of newts were investigated. For the first time changes in Müller glial cells in the retina of eyes regenerating after retinal detachment were detected in newts exposed to clinorotation. The cells divided, were hypertrophied, and their processes were thickened. Such changes suggested reactive gliosis and were more significant in animals exposed to rotation when compared with desk-top controls. Later experiments onboard the Russian biosatellite Bion-11 showed similar changes in the retinas that were regenerating in a two-week spaceflight. In the Bion-11 animals, GFAP, the major structural protein of retinal macroglial cells, was found to be upregulated. In a more recent experiment onboard Foton-M3 (2007), GFAP expression in retinas of space-flown, ground control (kept at 1 g), and basal control (sacrificed on launch day) newts was quantified, using microscopy, immunohistochemistry, and digital image analysis. A low level of immunoreactivity was observed in basal controls. In contrast, retinas of space-flown animals showed greater GFAP immunoreactivity associated with both an increased cell number and a higher thickness of intermediate filaments. This, in turn, was accompanied by up-regulation of stress protein (HSP90) and growth factor (FGF2) expressions. It can be postulated that such a response of Müller cells was to mitigate the retinal stress in newts exposed to microgravity. Taken together, the data suggest that the retinal population of macroglial cells could be sensitive to gravity changes and that in space it can react by enhancing its neuroprotective function. 相似文献
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