1. Institute of Materials
Science, University of Connecticut, Storrs, Connecticut 06269-3136, United States
2. Key Lab of Advanced Ceramics and Machining Technology of Ministry
of Education, Tianjin University, Tianjin 300072, P. R. China
3. State Key
Laboratory of Solid Lubrication, Center of Eco-materials and Green
Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
4. Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States