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吉南浑江坳陷南缘重力滑覆构造特征 总被引:5,自引:2,他引:3
据军江地区1:5万区调资料,吉南浑江坳陷南缘发育一个由多个构造岩块组成的重力滑覆构造区,其内部自下而上可划分白山市,红旗,大梨树沟,横道河子四个滑覆体分别由新元古代一早古生代地层组成,滑覆于晚古生代地层之上,构成了所谓“四层楼”式的构造工,形成时代为早侏罗世。 相似文献
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J. S. B. Wyithe R. L. Webster E. L. Turner 《Monthly notices of the Royal Astronomical Society》1999,309(1):261-272
Determination of microlensing parameters in the gravitationally lensed quasar Q2237+0305 from the statistics of high-magnification events will require monitoring for more than 100 years (Wambsganss, Paczynski & Schneider). However, we show that the effective transverse velocity of the lensing galaxy can be determined on a more realistic time-scale through consideration of the distribution of light-curve derivatives. The 10 years of existing monitoring data for Q2237+0305 are analysed. These data display strong evidence for microlensing that is not associated with a high-magnification event. An upper limit of v t <500 km s−1 is obtained for the galactic transverse velocity, which is smaller than previously assumed values. The analysis suggests that the observed microlensing variation may be predominantly due to stellar proper motions. The statistical significance of the results obtained from our method will be increased by the addition of data points from current and future monitoring campaigns. However, reduced photometric errors will be more valuable than an increased sampling rate. 相似文献
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When a source star is gravitationally microlensed by a dark lens, the centroid of the source star image is displaced relative to the position of the unlensed source star, with an elliptical trajectory. Recently, routine astrometric follow-up measurements of these source star image centroid shifts by using high-precision interferometers have been proposed to measure the lens proper motion, which can resolve the lens parameter degeneracy in the photometrically determined Einstein time-scale. When an event is caused by a bright lens, on the other hand, the astrometric shift is affected by the light from the lens, but one cannot identify the existence of the bright lens from the observed trajectory because the resulting trajectory of the bright lens event is also an ellipse. As results, lensing parameters determined from the trajectory differ from those of a dark lens event, causing an incorrect identification of the lens population. In this paper, we show that although the shape and size of the astrometric centroid shift trajectory are changed because of the bright lens, the angular speed of centroid shifts around the apparent position of the unlensed source star is not affected by the lens brightness. Therefore, one can identify the existence of a bright lens and determine its brightness by comparing the lens parameters determined from the 'angular speed curve' with those determined from the trajectory of observed centroid shifts. Once the lens brightness is determined, one can correct for the lens proper motion. As the proposed method provides information about both the lens brightness (dark or bright) and the corrected values of the physical parameters of the lens, one can constrain the nature of massive compact halo objects (MACHOs) significantly better. 相似文献
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Using d'Alembert equation as the approximation of Einstein's equation, a solution is given in this paper to the time-dependent gravitational equation of the Earth in consideration of the Earth's features, which describes the characteristics of pulsation of the Earth and the structures of spherical layers of its interior, thus providing a theoretical basis for establishing the idea of mantle pulsation. 相似文献
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ZHU Zhuowen HUANG Jinshui CAO Huasheng LUO Zhicai 《地球空间信息科学学报》2000,3(2):41-46
1 IntroductionConventionalevaluatingmodelsofexternalgravi tationalfieldoftheeartharenothingelsethanakindofrealizationsofnumericalsolutionstogeode ticboundaryvalue problem .Inthesenseoflin earization ,geodeticboundaryvalueproblemsarere ducedtoexternalbound… 相似文献