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731.
Two methods of calculating the resultant vector and principal moment of light pressure forces, having an effect on a spacecraft
with a composite solar sail, are compared. The first method is based on analytical formulas obtained without regard to shading
of some parts of the sail by others. The second method uses a detailed geometrical model of the sail, which allows one to
take such shading into account. Some part of photons falling on a sail is supposed to be reflected from it in a mirror manner,
while the others are completely absorbed. The range of variation of sail orientation parameters with respect to incident solar
light streams, where the first method turns out to be accurate enough, is found. 相似文献
732.
N. N. Makarov A. A. Porunov V. V. Soldatkin V. M. Soldatkin 《Russian Aeronautics (Iz VUZ)》2008,51(2):188-197
In this paper, a problem of measuring the altitude-speed helicopter performance in the range of low and near-zero flight velocities is considered. The structural functional scheme of the omnidirectional helicopter air data system based on the stationary aerometric multichannel transducer (AMT) as well as the jet-convective measuring channels is shown and algorithms for the formation of the system output signals are presented. In order to extend the lower bound of operating speeds, it is proposed that the omnidirectional system be integrated with the aeromechanical measuring computer system that realizes the VIMI method with Luenberger’s observer. Also given is the algorithm support and the accuracy of the integrated system operation is estimated. 相似文献
733.
Recent progress in the research on deuterium-tritium (D-T) inertially confined microexplosions encourages one to reconsider the nuclear propulsion of spaceships based on the concept originally proposed in the Orion project. We discuss first the acceleration of medium-sized spaceships by D-T explosions whose output is in the range of 0.1–10 t of TNT. The launching of such a ship into an Earth orbit or beyond by a large nuclear explosion in an underground cavity is sketched out in the second section of the paper, and finally we consider a hypothetical Mars mission based on these concepts. In the conclusion it is argued that propulsion based on the Orion concept only is not the best method for interplanetary travel owing to the very large number of nuclear explosion required. A combination of a super gun and subsequent rocket propulsion using advanced chemical fuels appears to be the best solution for space flights of the near future.From Kosmicheskie Issledovaniya, Vol. 43, No. 1, 2005, pp. 67–75.Original English Text Copyright © 2005 by Linhart, Kravárik. 相似文献
734.
735.
Influence of clinorotation and fettering stress on tail regeneration of Triturus vulgaris (Urodela).
H J Anton E N Grigoryan K Krupp-Beyerlein H Pitzer V I Mitashov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,21(8-9):1159-1162
Tail-amputated adult Triturus vulgaris, fettered in cuvettes of a fast-rotating clinostat were exposed to simulated weightlessness (60 rpm; equiv. to 10(-3)-10(-4) g), during a 14-day period. To feed and clean the animals rotation was stopped once a day for approx. 10 min. To test the influence of the fettering stress, a second series of animals was kept separately under normal earth conditions without rotation. A further control series was kept in a dark container without any handicap. While tail regeneration of the rotated animals was markedly accelerated, the fettered-only animals showed a considerably less marked acceleration effect. At the end of the 14-day period, all regenerates were reamputated together with an additional 5 mm of the tail stump. Although this second level of amputation was distant from the first, the regenerative growth rate of the rotated series was accelerated 123% in contrast to both the control and the fettered-only series. Our results demonstrate that the growth acceleration is induced by clinorotation. Fettering stress has no comparable influence. The growth promoting effect is not limited to the regenerating area. 相似文献
736.
M.I. Panasyuk M.V. Teltsov V.I. Shumshurov V.V. Tsetlin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,21(12):1635-1638
Dose variations, associated with the 11-year solar activity cycle, seasonal variations of particle fluxes in the Earth's radiation belts at the station orbit, and solar proton events are studied, using prolonged measurements of radiation doses inside orbital station Mir. Daily averages of radiation doses during the declining phase of the 22nd solar cycle and during transition to the 23rd solar activity cycle reached very large values for astronauts and significantly exceed the values calculated according to existing models. 相似文献
737.
O. A. Zhuravlev E. V. Shakhmatov A. N. Kryuchkov N. D. Bystrov A. I. Dolgov 《Russian Aeronautics (Iz VUZ)》2009,52(4):463-467
The results of vibration tests for heavy-loaded elements in the auger-centrifugal stage of an aircraft fuel pump performed with the use of an interference-free digital speckle-interferometer created at the Samara State Aerospace University are presented. The speckle-interferograms of an auger and a centrifugal wheel of the auger-centrifugal pump stage in different conditions of attachment and dynamic loading are given. The data obtained may be of sufficient importance in the development of aircraft fuel pumps for a specified service life. 相似文献
738.
V. S. Moiseev D. S. Gushchina A. N. Kozar G. E. Borzov 《Russian Aeronautics (Iz VUZ)》2009,52(3):372-375
We propose a mathematical model and the numerical method for an optimal choice of unmanned aerial vehicles (UAVs) from those
being in flight to fulfill a newly received order for monitoring (reconnaissance) of a new region. Examples of using the approach
being proposed and main lines of its realization in promising information unmanned aircraft complexes (UAC) are presented. 相似文献
739.
S. A. Mikhailov A. Yu. Onushkin Yu. P. Onushkin A. A. Safonov S. I. Kochish 《Russian Aeronautics (Iz VUZ)》2009,52(3):296-301
The algorithms for calculating available overloads and maneuvers are presented. Nesterov’s loop maneuver is analyzed. 相似文献
740.
With allowance made for thermoelasticity of working surfaces and inertia forces on the lubricant coat, a hydrodynamic problem
is solved for the noncontacting face seals with microgrooves in the high-speed rotors of FV engines. Also shown are the initiation
of surface waviness in the zone of lubricant coat fracture and the influence of its amplitude upon the seal characteristics. 相似文献