Liu, Jianhua
Yang, Jianguo
Liu, Huaping
Tian, Xingjun
Gao, Meng
Funding for this research was provided by:
Chinese High-tech R & D (863) Program (2007AA04Z232)
National Natural Science Foundation of China (CN) (61075027)
Natural Science Foundation of China (91120011)
Natural Science Foundation of Hebei province (F2010001106, F2013210094)