1. Department of Physics City University of Hong Kong Kowloon, Hong Kong China
2. Department of Materials Science and Engineering City University of Hong Kong Kowloon, Hong Kong China
3. Department of Mechanical Engineering The University of Hong Kong Pokfulam, Hong Kong China
4. Institute of Process Engineering, Innovation Academy for Green Manufacture Chinese Academy of Sciences Beijing China
5. School of Automobile and Traffic Engineering Jiangsu University of Technology Changzhou China
6. Department of Biomedical Engineering City University of Hong Kong Kowloon, Hong Kong China