1. Yancheng Institute of Technology, Yancheng, People's Republic of China
2. College of Science, Hohai University, Nanjing, People's Republic of China
3. College of Mathematics and System Science, Shandong University of Science and Technology, Qingdao, People's Republic of China
4. Science and Information College, Qingdao Agricultural University, Qingdao, People's Republic of China