ZHAO De-hui,XU Jin-yu,ZHANG Yan,YAO Huan-zhong
1. The Engineering Institute, Air Force Engineering University, Xi′an, Shaanxi 710038, China; 2. Mechanics and Civil Engineering institute, Northwestern Polytechnic University, Xi′an, Shaanxi 710072, China; 3. Air Force Logistic Dept. in Nanjing Army Distric, Nanjing, Jiangsu 210018, ChinaV55