1. Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong.
2. Department of Physics, National Changhua University of Education, Changhua 50007, Taiwan.
3. National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, China.
4. Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan.
5. National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, and Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.
6. School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
7. Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong.
8. Department of Nuclear Science and Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
9. Nano-Manufacturing Laboratory (NML), Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China.