1. Department of Physics, Faculty of Science, Naresuan University, Phitsanulok, 65000, Thailand
2. China Institute of Atomic Energy, P. O. Box 275(18), Beijing 102413, People's Republic of China
3. School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
4. Department of Physics, Tianshui Normal University, Tianshui 741000, Gansu, China