1. College of Physics, Hebei Normal University, Shijiazhuang 050024, China
2. Korea Astronomy and Space Science Institute, Daejeon 34055, Korea
3. University of Science and Technology, Yuseong-gu 217 Gajeong-ro, Daejeon 34113, Korea
4. School of Electrical and Electronic Engineering, Wuhan Polytechnic University, Wuhan 430023, China
5. Department of Astronomy, Beijing Normal University, Beijing 100875, China
6. National Centre for Nuclear Research, Pasteura 7, PL-02-093 Warsaw, Poland