1. Army Engineering University of PLA-Shijiazhuang Campus, Shijiazhuang, Hebei 050003, P. R. China
2. Naval Aeronautical University, Yantai, Shandong, 264000, P. R. China
3. Hebei Jiaotong Vocational and Technical College, Shijiazhuang, Hebei 050003, P. R. China