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排序方式: 共有1021条查询结果,搜索用时 153 毫秒
1.
摘要: 为满足未来脉冲星导航和空间天文观测任务对X射线望远镜的载荷需求,Wolter I光学系统的研制正逐渐成为新的研究热点,电铸镍方案是当前国内外X射线光学系统镜筒制造的主要技术方案.文章对电铸镍X射线光学系统制造工艺、国内外研制现状、未来应用需求进行了介绍和整理,梳理了电铸镍X射线光学系统研制遇到的关键技术和难点,提出了后续研究发展建议,以促进中国在 X射线脉冲星自主导航、空间探测领域的快速发展. 相似文献
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P.B. Marty S. Bardeau O. Czoske H. Ebeling J.P. Kneib R. Sadat I. Smail 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,34(12):2509-2515
We present an analysis of seven clusters observed by XMM-Newton as part of our survey of 17 most X-ray luminous clusters of galaxies at z 0.2 selected for a comprehensive and unbiased study of the mass distribution in massive clusters. Using the public software FTOOLS and XMMSAS we have set up an automated pipeline to reduce the EPIC MOS and pn spectro-imaging data, optimized for extended sources analysis. We also developped a code to perform intensive spectral and imaging analysis particularly focussing on proper background estimate and removal. XMM-Newton deep spectro-imaging of these clusters allowed us to fit a standard β-model to their gas emission profiles as well as a standard MEKAL emission model to their extracted spectra, and test their inferred characteristics against already calibrated relations. 相似文献
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D.I. Kosenko S.I. Blinnikov K.A. Postnov P. Lundqvist E.I. Sorokina 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,34(12):2705-2710
Time-dependent thermal X-ray spectra are calculated from physically plausible conditions around GRB. It is shown that account for time-dependent ionization processes strongly affects the observed spectra of hot rarefied plasma. These calculations may provide an alternative explanation to the observed X-ray lines of early GRBs afterglows (such as GRB 011211). Our technique will allow one to obtain independent constraints on the GRB collimation angle and on the clumpiness of circumstellar matter. 相似文献
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Rudy Wijnands 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,38(12):2684-2688
I present a short overview of the behavior and properties of the two simultaneous kilohertz quasi-periodic oscillations (kHz QPOs) seen in the accreting millisecond X-ray pulsar SAX J1808.4–3658. I will focus on the behavior of the upper frequency QPO as a function of time and count rate as seen during the 2002 outburst of this source. I will also discuss briefly the correlated behavior of this QPO with QPOs at lower frequencies (several tens of hertz). 相似文献
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Nazar R. Ikhsanov Chul-Sung Choi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,38(12):2901-2902
The state of subsonic propeller is intermediate between the states of supersonic propeller and accretor in the evolutionary tracks of magnetized compact stars. The rotational rate of a star at this stage decelerates due to the interaction between its magnetosphere and the surrounding hot, quasi-static plasma envelope. The magnetospheric radius is smaller than the corotation radius and the boundary of the magnetosphere is stable with respect to interchange instabilities. The rate of the mass flux from the inner radius of the envelope to the stellar surface is limited by the rate of plasma diffusion into the magnetic field of the star. As a result, the subsonic propeller would appear as a low-luminosity accretion-powered pulsar with a soft X-ray spectrum. 相似文献
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根据工作实践研究了固体发动机切线照相无损检测中黑度分布、散射线防治、象质计使用、检测概率计算、脱粘临界值确定等技术问题. 相似文献
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逆合成孔径雷达信号处理方法研究进展 总被引:3,自引:0,他引:3
朱兆达 《南京航空航天大学学报》1995,27(1):59-66
在简要评述国内外现有的逆合成孔径雷达(ISAR)信号处理的运动补偿和成象方法之后,介绍了南京航空航天大学ISAR课题组近年来在ISAR信号处理方法研究中取得的主要进展,包括基于多散射点定位观点的雷达成象观测模型,基于最大似然原理的同时运动补偿和成象方法,基于最大似然原理的多目标成象方法和基于时频分析的多目标成象方法,以及超分辩成象方法,文末指出了在ISAR信号处理方面有待进一步研究的问题。 相似文献