1. School of Materials Science and Engineering
2. Zhengzhou University
3. Zhengzhou 450001
4. P. R. China
5. Graduate School of Science and Technology
6. Energy Conversion Engineering Lab
7. Institute of Regional Innovation
8. Aomori 030-0813
9. Japan
10. Department of Chemical Engineering
11. Hirosaki University
12. Hirosaki 036-8560
13. Taiyuan University of Technology
14. Taiyuan