1. School of Material and Chemical Engineering, Zhongyuan University of Technology, Zhengzhou, 450007 P. R. China
2. Henan Key Laboratory of Functional Salt Materials, Center for Advanced Materials Research, Zhongyuan University of Technology, Zhengzhou, 450007 P. R. China
3. Department of Stomatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 P. R. China