1. Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen, Fujian 361005, P. R. China
2. Fujian Key Laboratory of Advanced Materials (Xiamen University), Xiamen, Fujian 361005, P. R. China
3. Key Laboratory of High Performance Ceramics Fibers (Xiamen University), Ministry of Education, Xiamen, Fujian 361005, P. R. China