Affiliation: | HE Feng1 , HE Shoujie1,2 , ZHAO Xiaofei1 , GUO Bingang3 , OUYANG Jiting1 1 School of Physics, Beijing Institute of Technology, Beijing 100081, China 2 College of Physics Science and Technology, Hebei University, Baoding 071002, China 3 Lions Mansion Akashi Okubo 508, Okubo-machi 306, Okubo-cho, Akashi, Hyogo 674-0067, Japan |