1. Chongqing Medical and Pharmaceutical College, Chongqing 401331, P. R. China
2. Northwest Engineering Corporation, Shaanxi, Xi’an 710065, P. R. China
3. Chongqing University of Science and Technology, Chongqing 401331, P. R. China
4. Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, Henan Agricultural University, Henan, Zhengzhou 450002, P. R. China