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441.
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   
442.
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   
443.
"I can't get that stupid kite in the air! I can't! I can't!" "Oh, come on now, Charlie Brown ... that's no way to talk. The whole trouble with you is that you don't believe in yourself! You don't believe in your own abilities. You've got to say to yourself, 'I believe that I can fly this kite.' Now, go ahead, say to yourself, ' I believe that I can fly this kite.'" "I believe that I can fly this kite." "All right, now say it out loud. Say it over and over." "I believe that I can fly this kite! I believe that I can fly this kite! I actually believe I can fly this kite!" "You do? I'll bet you ten-to-one you're wrong!"  相似文献   
444.
445.
In satellite-to-helicopter communications, interference exists on the incoming signal when the receiving antenna is located below the rotor blades. A bound is established for the performance of a coherent fixed-tone ranging system operating at L band in this interference environment. The scalar diffracted field beneath the rotating blades, at L band and above, is found to satisfy the criterion of Fresnel diffraction, and is computed using the techniques of Fourier optics. The diffracted field is expressed in terms of a narrow-band signal. The amplitude and phase components are calculated from a Fourier Series expansion using the FFT algorithm. The significant harmonics of the phase component of the interference combine with the baseband of the narrow-band, phase-modulated ranging signal. This results in CW interference, and in rearrangement of the first-order, sideband, ranging-tone channel powers. The degradation in ranging accuracy is evaluated by computing the signal-to-interference (SIR) ratio for a set of ranging tones. The post-detection (SIR)PD at the output of the correlator is shown to be a function of the amplitude of the phase harmonics of the interference, the relative difference between the ranging tone and interference center frequencies (a function of rotor speed), the rangetone modulation indices, and the post-detection filter noise bandwidth.  相似文献   
446.
The probability of error P(e) is computed in a binary communication system with a single-pole IF filter. The effect of time-bandwidth product foT and IF frequency to band width ratio f1/Ifo on P(e) is shown. The sampling time is optimized and the effect of nonoptimal sampling time on P(e) is calculated.  相似文献   
447.
Plots of performance degradation are used to compare the effects of fading and intersymbol interference in a two- component specular multipath digital communications channel. Similar plots are then used to compare two practical receivers designed to combat the interference. Degradation plots are shown to allow easy identification of each receiver's range of usefulness, as well as identification of variance bounds demanded of channel parameter estimates which the receivers require.  相似文献   
448.
The theory of nonlinear filtering has been applied to the problem of the attitude determination of a satellite. Two approximation methods have been studied with a view to practical implementation. Computer simulation results are included.  相似文献   
449.
Logistics support of a long duration space station will dictate a high degree of space flight activity to rotate personnel and transport supplies and equipment. Systems characteristics and mission requirements for space station logistics have been analyzed within the context of a broad spectrum of space missions. Preliminary concepts for a space shuttle system (space transportation) have been developed. This system can support not only a space station program, but a wide variety of space missions for both NASA and the DOD.  相似文献   
450.
Developing systems provide unique opportunities for analyzing the effects of microgravity on animals. Several unusual types of cells as well as various extraordinary cellular behavior patterns characterize the embryos of most animals. Those features have been exploited as test systems for space flight. The data from previous experiments are reviewed, and considerations for the design of future experiments are presented.  相似文献   
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