1. Department of Astronomy, Xiamen University, Xiamen, Fujian 361005, China
2. Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Ave, Ann Arbor, MI 48109-1107, USA
3. Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements (JINA-CEE), USA
4. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA