1. State Key Laboratory of New Ceramics and Fine ProcessingSchool of Materials Science and EngineeringTsinghua University Beijing 100084 P. R. China
2. Graduate School of EngineeringNagoya University Nagoya 464‐8603 Japan
3. College of Materials Science and EngineeringNanjing Tech University Nanjing 210009 China
4. Department of Chemistry and Center of Nano and Micro MechanicsTsinghua University Beijing 100084 P. R. China
5. Nagoya Industrial Science Research InstituteNagoya University Nagoya 464‐0819 Japan
6. Center of NanotechnologyKing Abdulaziz University Jeddah 21589 Saudi Arabia
7. School of Materials Science and EngineeringGuilin University of Electronic Technology Guilin Guangxi 541004 P. R. China