1. College of Chemistry, Chemical Engineering and Materials Science, Institute of Biomedical Sciences, Shandong Normal University, Jinan 250014, P.R. China
2. School of Physics and Electronics, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P.R. China
3. School of Physics and Information Engineering, Shanxi Normal University, Linfen 041004, P.R. China
4. College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P.R. China