1. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
2. Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore
3. Center for Intelligent Sensors and MEMS (CISM), National University of Singapore, Singapore 117576, Singapore
4. NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore