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521.
Using the method of characteristics, the problem of breaking or non-breaking of waves is studied in a plane cylindrically or spherically symmetric flow of an ideal dissociating gas. It is investigated as to how the effects of dissociation and that of the wave front curvature influence the breaking or non-breaking of waves. In a symmetrical converging gas motion a remarkable difference between the behaviours of cylindrical and spherical waves is discovered. 相似文献
522.
Jürgen Blumenberg 《Acta Astronautica》1981,8(8):839-854
In this paper it is shown how a nuclear power system with turboelectric conversion is being optimised for application in space and how data subject to the mission and technological data enter into such an analysis. Thereafter it follows a comparison with nuclear power systems with magnetofluiddynamic and thermionic converters. 相似文献
523.
P.T. Gallagher C.A. Young J.P. Byrne R.T.J. McAteer 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Coronal mass ejections (CMEs) are large-scale eruptions of plasma and magnetic field that can produce adverse space weather at Earth and other locations in the Heliosphere. Due to the intrinsic multiscale nature of features in coronagraph images, wavelet and multiscale image processing techniques are well suited to enhancing the visibility of CMEs and suppressing noise. However, wavelets are better suited to identifying point-like features, such as noise or background stars, than to enhancing the visibility of the curved form of a typical CME front. Higher order multiscale techniques, such as ridgelets and curvelets, were therefore explored to characterise the morphology (width, curvature) and kinematics (position, velocity, acceleration) of CMEs. Curvelets in particular were found to be well suited to characterising CME properties in a self-consistent manner. Curvelets are thus likely to be of benefit to autonomous monitoring of CME properties for space weather applications. 相似文献
524.
Martin A. Lee 《Space Science Reviews》2007,130(1-4):221-229
Gradual solar energetic particle (SEP) events are evidently accelerated by coronal/interplanetary shocks driven by coronal
mass ejections. This talk addresses the different factors which determine the composition of the accelerated ions. The first
factor is the set of available seed populations including the solar wind core and suprathermal tail, remnant impulsive events
from preceding solar flares, and remnant gradual events. The second factor is the fractionation of the seed ions by the injection
process, that is, what fraction of the ions are extracted by the shock to participate in diffusive shock acceleration. Injection
is a controversial topic since it depends on the detailed electromagnetic structure of the shock transition and the transport
of ions in these structured fields, both of which are not well understood or determined theoretically. The third factor is
fractionation during the acceleration process, due to the dependence of ion transport in the turbulent electromagnetic fields
adjacent to the shock on the mass/charge ratio. Of crucial importance in the last two factors is the magnetic obliquity of
the shock. The form of the proton-excited hydromagnetic wave spectrum is also important. Finally, more subtle effects on ion
composition arise from the superposition of ion contributions over the time history of the shock along the observer’s magnetic
flux tube, and the sequence of flux tubes sampled by the observer. 相似文献
525.
A possible variant presented for solving the equation of motion of a rotating flow is more general with respect to the variants known in the literature. On the basis of the simultaneous solution of the equations of motion and energy, the temperature fields are determined under changes of the rotation nature. 相似文献
526.
Radio frequency spectrum management for the 1970's is discussed, with the role of IEEE's Joint Technical Advisory Committee defined. 相似文献
527.
Russian Progress transport cargo vehicles have successfully been used in different space station programs since 1978. At present time, they play an important role in the International Space Station (ISS) project. Main tasks performed by the transport cargo vehicle (TCV) in the station program are the following: refueling of the station, delivery of consumables and equipment, waste removal, station attitude control and orbit correction maneuver execution. 相似文献
528.
One possible method is considered of deriving the well-posed (in the sense of A.N. Tikhonov) solutions to the problems of estimating the aircraft performance characteristics. The method is based on the results of measurements of the state parameters and geophysical conditions of the employment of the rocket-and-space facilities under conditions of uncertainty of the a priori data on measurement errors. 相似文献
529.
P. Laurent A. Claret F. Lebrun J. Paul M. Dennis D. Barret L. Bouchet P. Mandrou R. Sunyaev E. Churazov M. Gilfanov N. Khavenson A. Dyachkov B. Novikov R. Kremnev V. Kovtunenko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):139-148
After more than two years of operation, the imaging γ-ray SIGMA telescope has accumulated several days of observation toward well known X-ray binaries. Four bright sources falling in this category have been detected so far: The pulsar GX 1+4 near the center of our galaxy, the stellar wind accreting system 4U 1700-377, and the black hole candidates Cygnus X-1 and GX 339-4. Moreover, SIGMA have observed three transients sources, which turned out to be also hard X-ray sources : The burster KS 1731-260, Tra X-1, and the Musca Nova. The properties of these systems in the SIGMA domain will be reviewed and a spectral distinction between black holes and neutron stars will be sketched. 相似文献
530.
Frederick L. Scarf 《Space Science Reviews》1974,15(6):933-950
A study has been carried out to identify the controlled space physics and plasma physics experiments that can be performed from the space shuttle on sortie missions of 7 to 30-day duration. An experiment facility of this type appears to be well-matched to the sortie missions capability, and a technically feasible laboratory can provide a base for an extensive and significant research program to be carried out during the 1980–1990 time period. The laboratory, known as PPEPL, consists of a 33-ft pallet of instruments connected to a 25-ft pressurized control module. Two deployable 50-m booms, two subsatellites, a high power transmitter, a multipurpose high-power accelerator array, a set of deployable canisters for releases, and a gimbaled platform for pointing instruments are the primary systems mounted on the pallet. 相似文献