National Astronomical Observatories;
Chinese Academy of Sciences;
Beijing 100012;
China;
Graduate School of the Chinese Academy of Sciences;
Beijing 100049;
China;
Yunnan Observatory;
National Astronomical Observatories;
Chinese Academy of Sciences;
Kunming 650011;
China;
Center for Astrophysics;
University of Science and Technology of China;
Hefei 230026;
China;