1. Automation DepartmentInstitute of Engineering TechnologyUniversity of Science and Technology BeijingBeijing 100083People's Republic of China
2. School of Electrical, Computer and Telecommunications EngineeringUniversity of WollongongWollongongNSW 2522Australia
3. Material Industry & Development DepartmentAerospace Research Institute of Material & Processing TechnologyBeijing 100076People's Republic of China