1. State Key Laboratory of Ultra-Precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China
2. Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China
3. Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China