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511.
512.
A.A. Imshenetsky B.G. Murzakov M.D. Evdokimova I.K. Dorofeyeva 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(14):21-26
Results of the study of the influence of Martian soil analogues, both as described by American scientists and as prepared by us, and of hydrogen peroxide on the viability of microorganisms are presented. The experiments were carried out using mixtures of soil analogues with desert soil and black earth (chernozem) samples, and pure cultures of microorganism. Microorganisms capable of withstanding a concentration of hydrogen peroxide in the medium as high as 1.5–2.0% were isolated. None of the 40 strains of microorganisms studied, all belonging to different systematic and physiological groups, exhibited growth inhibition on solid media in the presence of Martian soil analogues. In view of the fact that Martian soil cannot contain microorganisms in great quantities, we suggest using electroadsorption for their concentration, to make detection reliable. A device was designed for this purpose, using the principle of electroadsorption on a polarisable carrier (sterile cotton wool or cheesecloth). The concentrated suspension of microorganisms thus obtained was then characterized by various physicochemical methods. 相似文献
513.
R.Z. Sagdeev G.G. Managadze A.A. Martinson Yu.A. Romanovsky R.I. Moisya W.K. Riedler M.F. Friedrich T.G. Adeishvily S.B. Lyakhov L.S. Novikov N.A. Leonov T.I. Gagua I.I. Slyusarenko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):129-140
This paper describes two rocket experiments “Aelita” with high power lithium plasma injection. The results of onboard magnetometer, massspectrometer, photometer, plasma, corpuscular and ground radar measurements are given. Dynamics and structure of plasma formation are discussed. 相似文献
514.
Koivo A.J. Kahne S.J. Koivo H.N. 《IEEE transactions on aerospace and electronic systems》1970,(3):306-312
The effect of bounded deterministic disturbances (external and/or internal) on a chosen performance index (PI) is investigated. Upper and lower bounds of the PI about a nominal value are determined by the application of the optimum control theory. A computational procedure is also proposed to determine an approximately optimal feedback controller for time-lag systems. Such a controller is designed here on the basis of min-max criteria. Numerical examples illustrate the proposed approach. 相似文献
515.
516.
E.M. El Shazly M.A. Abdel Hady M.A. El Ghawaby S.M. Khawasik M.M. El Shazly 《Acta Astronautica》1978,5(10):947-957
The Qattara Depression lies in the northern part of the Western Desert of Egypt at a distance of some tens of kilometers to the south of the Mediterranean Sea Coast. The depression in question is the largest one in the great Sahara extending across North Africa. It covers an area of some 19,000 km2 at ? 60 m level and the absolute level of its lowest point is about ? 134 m. The depression extends for about 300 km in a roughly ENE-WSW direction, while its width is variable reaching to a maximum of about 145 km. Feasibility studies are currently carried out for the Qattara solar-hydro-electric project which aims at generating hydro-electric power by the drop of the Mediterranean Sea water into the depression after passing through a canal/tunnel system. Peak load electric power may be also generated by raising the water to the small hollow of Deir Kirayim, situated at a higher level near the depression, and allowing it to drop to a low level.For the purpose of assessing the regional criteria involved in the implementation of the project and the environmental impact of such implementation, the Qattara Depression and the surrounding area has been studied on a regional scale by the utilization of LANDSAT satellite imagery. The maps produced by the interpretation of the images in question include those of the geological and environmental units, structural lineations, drainage and vegetation cover. Lineation density and drainage density maps are derived by the computation of the structural lineation and drainage maps respectively. A map of groundwater conditions is worked out on the basis of the image interpretation, and the observations previously carried out on the groundwater aquifers in the Qattara Depression and the surrounding area. LANDSAT satellite image interpretation and computation are supported by intensive observations carried out in the field as well as chemical, petrological and mineralogical analyses of the samples collected.The LANDSAT satellite images proved to be of great importance in mapping the Qattara Depression floor which is hardly accessible to classical mapping, and especially in view of the large area which could be covered by imagery mapping in a reasonably short time compatible with the duration of the feasibility study. The special characters of the spaceborne multispectral imagery have been paramount in deciphering the major regional features of the investigated area.The overall synoptic picture of the regional setting of the geological and environmental units, faults, fractures and folds, drainage lines and plant cover in the large area studied has been clarified for the first time. It has been demonstrated that the Qattara Depression is actually constituted of several small depressions. The environmental impact of the project implementation has been visualized especially regarding the possible influence of the saline water on the fresh groundwater sources. The thick salt accumulation in the depression has been found to be of such extension as to increase the salinity of the Mediterranean Sea water stored in the depression following the implementation of the project. The lineation density map has been particularly of great help in the localization of sites subjected to intense crustal deformation, greater slope instability and run off surface water flooding. 相似文献
517.
518.
In order to stabilize the altitude calculation in an inertial navigation system, an altimeter is commonly used. In a conventional local-level mechanization, this is generally accomplished by correcting the vertical channel integrators with the difference between the inertial system and altimeter indication of vertical position. However, in a space-stable system the procedure is not as clear since a vertical channel is not physically present. Three altitude damping mechanizations for a space-stable inertial navigation system are proposed. The equivalent local-level mechanizations are then found by comparing error propagation equations in a common coordinate frame. 相似文献
519.
The influence of sudden increases of electron content on the accurate determination of the position of a satellite is investigated based on a spherically stratified ionospheric model. Using the total electron content information from Faraday rotation measurements, a procedure is presented whereby the corrections of satellite position due to the unpredicted electron increase can be accounted for without the need to know the spatial distribution of the additional electrons. 相似文献
520.
We discuss the origin, evolution and fate of low-mass Algols (LMA) that have components with initial masses less than 2.5 M0. The semi-major axes of orbits of pre-LMA do not exceed 20–25 R0. The rate of formation of Algol-type stars is 0.01/year. Magnetic stellar winds may be the factor that determines the evolution of LMA. Most LMA end their lives as double helium degenerate dwarfs with M1/M2 0.88 (like L870-2). Some of them even merge through angular momentum loss caused by gravitational waves. 相似文献