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991.
对SGRs的主要观测特征--在软伽玛射线波段的重复爆发及持久性的周期的X射线辐射--进行了回顾,介绍了SGRs的一些理论模型,其中磁星(具有甚强磁场的中子星)模型较合理地解释了现有的观测事实。 相似文献
992.
We explore the capability of a method of mapping the depth distribution of a hydrogen-rich layer in the top meter of Mars from the neutron currents measured by the Mars Odyssey Neutron Spectrometer. Assuming the soil can be modeled by two layers of known composition having different hydrogen contents, simulations allow an inversion of the neutron data into knowledge of depth and hydrogen content of the lower layer. The determination of these variables is sensitive to the hypothesis of chemical composition of the soil. We quantify this contribution to the uncertainty in the method first in terms of individual chemical elements and then in terms of macroscopic absorption cross sections. To minimize this source of error, an average composition was inferred from Mars Exploration Rover data. Possible compositions having a wide range of macroscopic absorption cross sections were used to evaluate the uncertainty associated with our calculations. We finally compare our results to ice table depth estimates predicted by two published theoretical models at locations where the composition is relatively well known. The fit is excellent in the southern high latitudes but questionable in the northern high latitudes. Possible explanations of these differences include the high geographical variations of the neutron currents relative to the spatial width of the response function of the instrument and the overly simple model we, of necessity, used for surface layering. 相似文献
993.
M.G. Watson 《Astronomische Nachrichten》2008,329(2):131-134
This article compares and contrasts the virtues of planned (and normally contiguous) surveys with XMM‐Newton and the XMM‐Newton serendipitous sky survey and discusses various ways in which both the quality and efficiency of contiguous surveys with XMM‐Newton could potentially be improved. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
994.
The well defined selection function of the XMM‐LSS surveys enables a simultaneous modelling of the observed cluster number counts and of the evolution of the LX‐TX relation. We present results pertaining to the first 5 deg2 for a well controlled sample comprising 30 objects: they are compatible with the WMAP3 parameter set along with cluster selfsimilar evolution. Extending such a survey to 200 deg2 would (1) allow discriminating between the major scenarios of the cluster LX‐TX evolution and (2) provide a unique self‐sufficient determination of σ8 and Γ with an accuracy of ∼5% and 10% respectively, when adding mass information from weak lensing and S‐Z observations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
995.
We report on the diffuse X‐ray emission from the Galactic Centre (GCDX) observed with the X‐ray Imaging Spectrometer (XIS) on board the Suzaku satellite. The highly accurate energy calibration and extremely low background of the XIS provide many new facts on the GCDX. These are (1) the origin of the lines at 6.7 and 7.0 keV is collisional excitation in a hot plasma, (2) the discovery of new SNR and super‐bubble candidates, (3) most of the 6.4 keV line is X‐ray fluorescence, and (4) time variability of the 6.4 keV line is found from the Sgr B2 complex. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
996.
P. Kaaret 《Astronomische Nachrichten》2008,329(2):202-205
I discuss open questions regarding accreting black holes in binary systems, focusing on two questions: can we measure the spins of black holes and what is the nature of the ultraluminous X‐ray sources. XMM‐Newton could make significant strides in answering these questions and others over the next ten years. I suggest two observational programs designed to help increase our understanding of accreting black holes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
997.
V. I. Zatsepin A. D. Panov N. V. Sokolskaya J. H. Adams Jr. H. S. Ahn G. L. Bashindzhagyan J. Chang M. Christl A. R. Fazely T. G. Guzik J. B. Isbert K. C. Kim E. N. Kouznetsov M. Panasyuk E. S. Seo J. Watts J. P. Wefel J. Wu 《Astronomy Letters》2009,35(5):338-342
Titanium is a rare, secondary nucleus among Galactic cosmic rays. Using the Silicon matrix in the ATIC experiment, Titanium
has been separated. The energy dependence of the Ti to Fe flux ratio in the energy region from 5 GeV per nucleon to about
500 GeV per nucleon is presented.
The article was translated by the authors. 相似文献
998.
GIS在青岛海域管理中的应用 总被引:3,自引:1,他引:3
奥勇 《地球科学与环境学报》2004,26(2):71-74
阐述了基于GIS(地理信息系统)技术,对青岛海域使用管理系统进行设计与集成二次开发方法,通过MapX二次开发工具,实现了系统的主要功能,以直观的图面表示海域和相邻陆域海洋功能区类型,揭示了各区域的主导功能,突出了海洋功能特点,丰富了图件的信息量。 相似文献
999.
设计了一种用于工程监测的高精度倾斜仪。实验结果表明,该倾斜仪达到了设计目标,能满足工程监测应用的要求。 相似文献
1000.
曾旭 《成都信息工程学院学报》2012,27(1):59-62
讨论了数据挖掘技术在计算机等级考试评分系统中的应用。利用关联规则技术对考生的得分情况进行分析,得出各类题型之间的关联性。所得结论对提高考生的过级率以及教师后继教学工作的开展均具有一定的指导性。 相似文献