1. Department of Physics; Beijing Normal University; Beijing 100875 China
2. School of Materials Science and Engineering; Tsinghua University; Beijing 100084 China
3. Physical and Life Science Directorate; Lawrence Livermore National Laboratory; Livermore CA 94550 USA
4. EMAT (Electron Microscopy for Materials Science); University of Antwerp; Groenenborgerlaan 171 Antwerp 2020 Belgium
5. Frontier Institute of Science and Technology and State Key Laboratory for Mechanical Behavior of Materials; Xi'an Jiaotong University; Xi'an 710049 China
6. Department of Geriatric Dentistry; Peking University School and Hospital of Stomatology; Beijing 100081 China
7. Department of Materials Science and Engineering; Pennsylvania State University; University Park; PA 16802 USA
8. Centre for Advanced Structural Materials and Department of Mechanical and Biomedical Engineering; City University of Hong Kong; Tat Chee Avenue, Kowloon Tong, Kowloon Hong Kong 999077 China