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821.
N. F. Averkiev S. A. Vlasov V. V. Salov V. V. Kiselev 《Russian Aeronautics (Iz VUZ)》2016,59(4):474-479
A method of finding the aircraft optimal route by means of task-oriented replacement of the functional being optimized is proposed. 相似文献
822.
823.
A parallel computer specifically designed for the solution of ordinary differential equations is described. The first version of the machine contains thirty-two processors, running in an asynchronous multiple-instruction/multiple-data mode, communicating with high-speed parallel busses. Synchronization is accomplished by a microprogrammable communication controller. A number of processors have been designed and built for the machine. The processor types offer a wide variation in solution speed and accuracy. To permit easy comparisons with analog and hybrid systems, performance is measured by finding the highest frequency sine wave which can be integrated in real time with an accuracy of 0.1% or higher. Using this performance measure the performance limit of the current machine is 2000 Hz. The structure is capable of solving systems described by differential equations up to order sixty-four at these performance limits 相似文献
824.
Ehsani M. Bilgic M.O. Patton A.D. Mitra J. 《Aerospace and Electronic Systems Magazine, IEEE》1995,10(8):9-14
A new approach to superconductive magnetic energy storage (SMES) for solar power satellite (SPS) with inherent rigidity is introduced in this paper. The rigidity of this SMES originating from the electromagnetic forces within it, can eliminate the need for mechanical building blocks for support structure. This force can also be used for the deployment of the system in space. In addition, the storage capability of the system allows its use in low Earth orbit (LEO) which reduces the launching and transmission costs. The paper also discusses the basic design and the operation of the proposed SPS system 相似文献
825.
O G Gazenko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(10):29-37
The program of the 5 day flight of the biosatellite Cosmos-1514 (December 1983) envisaged experimental investigations the purpose of which was to ascertain the effect of short-term microgravity on the physiology, growth and development of various animal and plant species. The study of Rhesus-monkeys has shown in that they are an adequate model for exploring the mechanisms of physiological adaptation to weightlessness of the vestibular apparatus and the cardiovascular system. The rat experiment has demonstrated that mammalian embryos, at least during the last term of pregnancy, can develop in microgravity. This finding has been confirmed by fish studies. The experiment on germinating seeds and adult plants has given evidence that microgravity produces no effect on the metabolism of seedlings and on the flowering stage. 相似文献
826.
H. Nieuwenhuijzen F. P. Israel C. Slottje L. B. F. M. Waters J. Kleczek K. Werner M. Barylak Patricia Whitelock Ľ Kresák G. Meynet K. A. van der Hucht D. Stickland 《Space Science Reviews》1992,61(3-4):393-417
The general significance of streamers of the solar corona is discussed in the frame of our knowledge of the solar wind phenomenon and the large-scale solar magnetic structure. Thermodynamical and geometric parameters of streamers observed and measured at total solar eclipses are reviewed. Both the low part (in the form of a helmet with a cusp) and the external part (in the form of a stalk extended at many solar radii) are considered. The modelling of streamers starts with the analysis of effects produced by the solar wind flow on a magnetic structure. Facts and arguments are presented in favor of a model with a current sheet and reconnection processes going on along the axis of the streamer, especially in the non-collisional part of the radially extended streamer. Further development of the Pneuman and Kopp (1971) model is discussed, including difficulties occurring in the interpretation of a stationary solution. An empirical model satisfying observations is presented. Future researchs on streamers were discussed with emphasis on observations to be done with the space-borne coronagraphs on the SOHO spacecraft. 相似文献
827.
O Y Khorkavtsiv O R Kardash 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2001,27(5):989-993
In darkness, protonemata of Pohlia nutans (Hedw.) grew negatively gravitropically (upwards). However, not all filaments became gravitropic immediately after transfer to darkness. Some of them (~20%) for several days grew in different directions with respect to gravity. The apical cells of those protonemata predominantly contained multiple chloroplasts. The intensity of chlorophyll fluorescence rapidly decreased in the apical cells of such protonemata while starch content increased in comparison with upright growing protonemata. Light, especially in the red and blue part of the spectrum, inhibited protonemal gravitropism. Red light induced stronger inhibitory effects than blue light. Red light of 1.0 to 1.5 micromoles m-2 s-1 intensity induced bud differentiation in apical cells on almost all side branches of main protonemal filaments. Bright fluorescence of F-actin bundles in the tip of apical protonematal cells and a delicately fluorescing network enclosing plastids basal to the tip in a sedimentation zone were visualized. Bright fluorescence of actin as local patches and fine prominent axially oriented bundles was observed in cells of gametophore buds. 相似文献
828.
The study of the electrical environment of the Earth’s atmosphere has rapidly advanced during the past century. Great strides have been made towards the understanding of lightning and thunderstorms and in relating them to the global electric circuit. The electromagnetic fields and currents connect different parts of the Earth’s environment, and any type of perturbation in one region affects another region. Starting from the traditional views in which the electrodynamics of one region has been studied in isolation from the neighboring regions, the modern theory of the global electrical circuit has been discussed briefly. Interconnection and electrodynamic coupling of various regions of the Earth’s environment can be easily studied by using the global electric circuit model. Deficiencies in the model and the possibility of improvement in it have been suggested. Application of the global electric circuit model to the understanding of the Earth’s changes of climate has been indicated.This revised version was published online in July 2005 with a corrected cover date. 相似文献
829.
We present the results of spectral analysis of a signal of oblique sounding of the ionosphere. This signal was received at the Doppler phase-angle measuring facility of Kazan University during the geomagnetic storm on October 29–31, 2003. On various short-wave (SW) radio paths, intense variations of Doppler frequency shift were observed. These variations exceeded variations observed on days without geomagnetic disturbances by an order of magnitude (and by two orders of magnitude during some short periods). Relatively short periods (1–3.5 min) are predominant on these days in variations of the Doppler frequency shift. It should be noted that, while for weak geomagnetic disturbances the response in the form of distortions of SW signal parameters was observed, as a rule, only for the paths coming from high-latitude regions, in the given case the effect was observed for all radio paths.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 640–644.Original Russian Text Copyright © 2004 by Bochkarev, Petrova, Teplov. 相似文献
830.
O. Kjeldseth-Moe 《Space Science Reviews》1994,70(1-2):123-130
A review is given of the activities of the working group on small scale features at the 2nd SOHO Workshop on Elba, 27 September–1 October 1993. The small scale and filamentary structure of the solar transition region, and possibly also the corona, was pointed out. The reported observations furthermore demonstrated that the upper solar atmosphere is strongly dynamical, containing rapidly flowing gas and with features changing with time. Theoretical concepts and simulations of conditions in the transition region and corona were presented and discussed. Finally some ideas on future observations and modelling were put forward. 相似文献