1. Department of Astronomy, Beijing Normal University No. 19, XinJieKouWai St., Beijing 100875, China
2. Xinjiang Astronomical Observatory, Chinese Academy of Sciences No. 150, Science 1-Street, Urumqi 830011, Xinjiang, China
3. Nanjing Institute of Astronomical Optics & Technology, National Astronomical Observatories, Chinese Academy of Sciences, Nanjing 210042, China