1. Department of Biomedical Engineering City University of Hong Kong Hong Kong 999077 P. R. China
2. Hong Kong Centre for Cerebro‐Cardiovascular Health Engineering Hong Kong 999077 P. R. China
3. State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering Mechanics Dalian University of Technology Dalian 116023 P. R. China
4. Ningbo Institute of Dalian University of Technology Ningbo 315016 P. R. China
5. State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China (UESTC) Chengdu 610054 P. R. China