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951.
T.F. Tuan D. Papadopoulos A.W. Peterson R.M. Nadile 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(10):137-141
The effects of gravity waves on OH and 5577 0I emissions have been used to investigate (1) the possible production of “secondary” waves or “ripples” by a “primary” wave; (2) the possible application of such observed optical emissions for computing atmospheric parameters such as turbulence viscosity in the mesospheric regions. 相似文献
952.
W. K. H. Schmidt 《Space Science Reviews》1981,30(1-4):615-621
Recently there was a suggestion in the literature to apply the principle of the lobster-eye to X-ray astronomy imaging (J.R.P. Angel, Ap. J. 233, 364, 1979). Our own suggestion for a wide angle X-ray telescope made earlier (W.K.H. Schmidt, Nucl. Instr. Meth.127, 285, 1975) is very similar to the above one. It consists of one or two sets of plane mirrors used in a grazing incidence configuration. The advantages of this type of X-ray optics over other systems for particular astronomical observations will be discussed. 相似文献
953.
D E Philpott J Miquel 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1986,6(11):233-242
Eight month old male C57BL6 mice were exposed without anesthesia to whole-body irradiation in circular holders. The mice were tested for behavioral decrements after 0.5 and 50 rads of Fe particle irradiation at 6 and 12 months post irradiation to obtain long term results. A standard maze was used and the animals were timed for completion thereof. A string test also was administered to the mice, testing their ability to grasp and move along a string to safety. The results from animals exposed to 50 rads were significantly different from [correction of fron] control results to p = < .001 in both systems of testing. The hippocampus (believed to be the location of environmental interaction in the brain) and the retina were examined for ultrastructural changes. The ultrastructural changes were similar to those we found in our Cosmos 782, 936 and in our Argon experiments. The mouse data indicate that iron particles were able to induce long term changes in the central nervous system which lead to behavioral impairment. 相似文献
954.
955.
L. D. De Feiter 《Space Science Reviews》1972,13(4-6):827-842
Recent observations of the energetic particles produced in solar flares indicate that the production of electrons, with energies up to about 100 keV, is a fairly common feature of small flares. In those flares the acceleration of protons and other nuclei does not extend beyond about 1 MeV.The X-ray emission often exhibits two distinct components of which the first one is produced by non-thermal, the second by thermal electrons through bremsstrahlung collisions with the ambient ions. Along with these X rays, radio emission, in the microwave region, is observed. This radio emission is usually interpreted as due to gyrosynchrotron radiation from the same electrons.In this review a discussion is presented of the processes occurring in solar flares with special reference to the acceleration and radiation processes. 相似文献
956.
This paper presents the pointing vector and angular rate relationshipsfor various optical elements as well as techniques developed forestablishing comprehensive analytical models of precision electroopticalstabilization systems. Since the performance of such systemsmay be critically dependent on the disturbance environment and theintegrity of the associated mechanism, these factors are also examinedin detail. 相似文献
957.
A numerical method is developed for the calculation of steady-state FM distortion in a linear passive network from the character of the FM signal input and the steady-state transfer characteristics of the network. The method of calculating FM distortion requires the solution of a finite set of linear equations which is accomplished readily by a digital computer. To illustrate the use of the method, the FM distortion introduced by a Chebyshev-response bandpass filter is calculated for a range of network and input signal parameters. 相似文献
958.
Rajasekaran P.K. Srinath M.D. 《IEEE transactions on aerospace and electronic systems》1969,(6):984-988
The problem of minimum time frequency transitions in phase-locked loops with both phase and frequency controls applied is investigated using Pontryagin's maximum principle. Typically, a type II secondorder loop with a damping ratio of 0.707 subjected to a step change in the frequency of its input signal is considered and switchless control strategies that force the transients in the loop to settle down in minimum time are obtained. 相似文献
959.
The current status of the theoretical methods for producing the relevant atomic data is surveyed.Proceedings of the Conference Solar Physics from Space, held at at the Swiss Federal Institute of Technology Zurich (ETHZ), 11–14 November 1980. 相似文献
960.
This paper is concerned with a high-performance nutation damper for use in dual-spin spacecraft. The damper described here makes use of a wheel of uniform mass distribution. The wheel experiences torques which are produced by inertial forces. Damping and restoring (spring) torques are provided by means of a torsional arrangement built around the center of the wheel. The performance characteristics of the above nutation damper are evaluated by considering the small astronomy satellite (SAS-A) spacecraft parameters, and the results for an optimum design of the damper are presented. Finally, the result for the optimum performance is checked with the help of an approximate analysis. 相似文献