1. School of Materials Science and Engineering Anhui Polytechnic University Wuhu 241000 P. R. China
2. Anhui Xinke New Materials Stock Co., Ltd. Wuhu 241006 P. R. China
3. Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming 650093 P. R. China
4. School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China