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831.
V. Sch nfelder K. Bennett H. Bloemen H. de Boer M. Busetta W. Collmar A. Connors R. Diehl J. W. den Herder W. Hermsen L. Kuiper G. G. Lichti J. Lockwood J. Macri M. McConnell D. Morris R. Much J. Ryan G. Stacy H. Steinle A. Strong B. Swanenburg M. Varendorff C. de Vries C. Winkler 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):647-655
COMPTEL is the first imaging telescope to explore the MeV gamma-ray range (0.7 to 30 MeV). At present, it is performing a complete sky survey. In later phases of the mission selected celestial objects will be studied in more detail. The data from the first year of the mission have demonstrated that COMPTEL performs very well. First sky maps of the inner part of the Galaxy clearly identify the plane as a bright MeV-source (probably due to discrete sources as well as diffuse radiation). The Crab and Vela pulsar lightcurves have been measured with unprecedented accuracy. The quasars 3C273 and 3C279 have been seen for the first time at MeV energies. Both quasars show a break in their energy spectra in the COMPTEL energy range. The 1.8 MeV line from radioactive 26A1 has been detected from the central region of the Galaxy and a first sky map of the inner part of the Galaxy has been obtained in the light of this line. Upper limits to gamma-ray line emission at 847 keV and 1.238 MeV from SN 1991T have been derived. Upper limits to the interstellar gamma-ray emissivity have been determined at MeV-energies. Several cosmic gamma-ray bursts within the field-of-view have been located with an accuracy of about 1°. On 1991 June 9, 11 and 15, COMPTEL observed gamma-ray emission (continuum and line) from three solar flares. Also neutrons were detected from the June 9 and June 15 flares. 相似文献
832.
K. Hurley 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):679-685
The results obtained on cosmic gamma-ray bursts over the last several years are reviewed and compared with the older “historical” results. Fine time resolution measurements of burster light curves continue to reveal structure at the millisecond and sub-millisecond level, suggesting a compact object origin. Similarly, the evolution of the low energy X-ray spectra of bursts towards shapes consistent with 1–2 keV blackbodies may be interpreted in terms of a neutron star origin, as can the continuing detection of absorption and emission features. The statistical evidence, however, argues strongly for an isotropic distribution which has been completely sampled. To reconcile this with galactic neutron stars requires the assumption that they are Population II objects. Counterpart searches have evolved to the point where they may be carried out within days of an event, and a soft X-ray source has now been detected in the error box of one recent burst. 相似文献
833.
R. Buccheri K. Bennett M. Busetta A. Carrami ana W. Collmar A. Connors W. Hermsen L. Kuiper G. G. Lichti V. Sch nfelder J. G. Stacy A. W. Strong 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):727-730
Pulsar measurements performed by the experiment COMPTEL, aboard the Compton Gamma Ray Observatory, are described. The main results refer to the Crab and Vela pulsars whose pulse shape characteristics are given in some detail and light curves are compared with those above 50 MeV, as observed by the COS-B satellite. No other gamma-ray pulsars have been detected to date by COMPTEL, the upper limit on the pulsed signal from Geminga being compatible with indications by other experiments. 相似文献
834.
835.
The structural features of the germanium-silicon solid solution crystals obtained under microgravity
V.S. Zemskov I.N. Belokurova I.L. Shulpina A.N. Titkov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(5):11-14
Structural features of germanium-silicon solid solution crystals have been investigated and silicon distribution in the crystals has been studied. All the crystals obtained under microgravity had, in spite of good external shape and facetting, a poorer internal structure than those obtained on Earth. The distribution of silicon have been shown to be non-uniform. High dislocation densities were observed. 相似文献
836.
The application of Fourier Transform Spectroscopy (FTS) to planetary research is reviewed. The survey includes FTS observations of the Sun, all the planets except Uranus and Pluto, the Galilean satellites and Saturn's rings. Instrumentation and scientific results are considered. The prospects and limitations of FTS for planetary research in the forthcoming years are discussed. 相似文献
837.
Chetty P.R.K. Polivka W.M. Middlebrook R.D. 《IEEE transactions on aerospace and electronic systems》1980,(2):191-201
A new approach to the design of power systems is presented in which a microprocessor is used as a controller for a digital shunt regulator (DSR). This approach meets the demands of future space and ground missions, i. e., high efficiency, high reliability, low weight, low volume, increased flexibility, and less development time. This approach responds to future demands by permitting realtime modification of system parameters for system optimization. This feature is especially important in the event of an anomaly. As the microprocessor need not be dedicated to the DSR, it can simultaneously be used for battery management and for charge regulator/discharge regulator control. This approach also reduces the component count, simplifies assembly and testing of the unit, results in significant time saving, and increases the reliability. 相似文献
838.
839.
B.K. Flint 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(4):135-142
A number of new high efficiency optical coatings have recently been developed at wavelengths in the ultraviolet and vacuum ultraviolet for use in space science experiments. The development of these coatings has resulted in the design and manufacture of wavelength selective filters used in reflectance at near normal incidence that have high VUV reflectance with little near-UV and visible reflectance. Very narrow band transmission filters are now available at wavelengths as short as 1500Å with bandwidths as narrow as 35–40Å. In addition, high efficiency anti-reflection coatings as well as neutral density filters are now available at many wavelengths in this region.Material limitations, more severe than those in the visible, place certain restrictions on the size, wavelength, and degree of selectivity that is achievable with present technology. A summary of the current commercial technology along with the material limitations is presented. 相似文献
840.
Incremental planning to control time-constrained blackboard-basedproblem solver [vehicle monitoring]
A planner that improves the control decisions made by a blackboard-based problem solver is described. This planner interleaves planning and execution. It sketches out major plan steps but incrementally details actions for only the next step since earlier actions influence how (and whether) to pursue a plan. The planner also reasons about time constraints, revising plans to meet problem-solving deadlines and deciding when it has done enough work on a problem. Implementation of these mechanisms is outlined, and experiments are discussed showing how they reduce overall computation and improve problem solving 相似文献