基金项目: | Supported by the National Natural Science Foundation of China.Acknowledgements This research has made use of data obtained from the High Energy Astrophysics Science Archive Research Center (HEASARC) provided by NASA's Goddard Space Flight Center. The authors would like to express their hearty thanks to all the members of the RXTE Science Working Group. This work was partially supported by the Grant-in-Aid for Scientific Research on Priority Areas (Grant No. 14079101). We acknowledge financial supports from the National Natural Science Foundation of China (Grant No. 10778702), the National Basic Research Program of China (973 Program, Grant No. 2009CB824800), and the Policy Research Program of Chinese Academy of Sciences (KJCX2-YWT24). |