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31.
We present a photometric study of the luminous early-type star Car. The star's secular brightness increase is due largely to the expansion of the Homunculus. Car is a LBV with a possible B0.5V companion. The combined effect of Balmer-line emission, and of warm and cold dust radiation explains the star's other light variations. 相似文献
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ABSTRACTThis article addresses the topic of conceptual representation of shadows. We analyze several examples of contemporary imagery, taken from advertising and cartooning, to shed light on the way shadow depictions are used as rhetorical devices. Instead of being inserted as a natural phenomenon, rhetorical shadows invite the construction of meaning, and instead of being a mere natural companion of their casters, they reveal things about their casters. Three so-called “shadow incongruity types” are distinguished: (1) shadows revealing the “true nature” of their caster or the “hidden contents” of the caster’s mind; (2) shadows marking some transition their caster is involved in; and (3) shadows suggesting a certain quality attached to one of a shadow’s main ingredients (casting object, light source or surface). For each of these types of rhetorical shadows, we demonstrate that the way they convey meaning basically follows the principles of perceiving and understanding natural shadows. 相似文献
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J. Schrijver A. C. Brinkman H. van der Woerd M. G. Watson A. R. King J. van Paradijs M. van der Klis 《Space Science Reviews》1985,40(1-2):121-126
We report results from EXOSAT observations of the intermediate polar system 2A0526-328 (TV Col). The hard X-ray emission (2–8 keV) is modulated with a period of 1943 s, interpreted as the white-dwarf rotation period. Soft and hard X-ray emission show intensity minima, in phase with the orbital period of 0.2286 days; analysis of the hard X-ray spectra shows that these minima are caused by an extra low-energy absorption corresponding to a H column density of 4 × 1022 cm-2. 相似文献
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Sounding rocket experiment of bare electrodynamic tether system 总被引:1,自引:0,他引:1
Hironori A. Fujii Takeo Watanabe Hirohisa Kojima Koh-Ichiro Oyama Tairo Kusagaya Yoshiki Yamagiwa Hirotaka Ohtsu Mengu Cho Susumu Sasaki Koji Tanaka John Williams Binyamin Rubin Charles Les Johnson George Khazanov Juan R. Sanmartin Jean-Pierre Lebreton Erick J. van der Heide Michiel Kruijff Fabio De Pascal Pavel M. Trivailo 《Acta Astronautica》2009,64(2-3):313-324
An overview of a sounding rocket, S-520-25th, project on space tether technology experiment is presented. The project is prepared by an international research group consisting of Japanese, European, American, and Australian researchers. The sounding rocket will be assembled by the ISAS/JAXA and will be launched in the summer of 2009. The sounding rocket mission includes two engineering experiments and two scientific experiments. These experiments consist of the deployment of bare electrodynamic tape tether in space, a quick ignition test of hollow cathode system in space, the demonstration of bare electrodynamic tether system in space, and the test of the OML (orbital-motion-limit) current collection theory. 相似文献
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Van der Wal P. van Willigen D. 《IEEE transactions on aerospace and electronic systems》1978,(4):649-661
The combination of an antenna, a 100 kHz bandpass filter, a hard limiter, and a sequential detector can supply highly accurate Loran-C data to a digital processor, even under low signal-to-noise-ratio conditions. For such a simple, low-cost receiver, calculations are given for the accuracy of the envelope and phase tracking of the Loran-C signal as a function of the signal-to-noise (Gaussian and atmospheric) ratio, averaging time, and radian speed of the observer with respect to the transmitter. Mentioned are the quasi-noise censoring effects of the hard limiter. Besides the Loran-C application, the hard limiter-sequential detector system can in general be applied for low-cost, synchronous signal detection under poor signal-to-noise ratio. 相似文献