Project supported by the National Basic Research Program of China (973 Program) (No. 2011CB610300), the 111 Project (No.B07050), the National Natural Science Foundation of China (Nos. 10972182, 11172239, and 10902089), the Doctoral Program Foundation of Education Ministry of China (No. 20106102110019), the Open Foundation of State Key Laboratory of Structural Analysis of Industrial Equipment (No. GZ0802), and the Doctorate Foundation of Northwestern Polytechnical University (No.CX201111)