1. College of Chemistry and Chemical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, P. R. China
2. Key Laboratory of Auxiliary Chemistry & Technology for Chemical Industry, Ministry of Education, Shaanxi University of Science & Technology, Xi'an 710021, P. R. China
3. Department of Information Engineering, Shaanxi Polytechnic Institute, Xianyang 712000, P. R. China
4. Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S10 2TN, UK
5. College of Geosciences, China University of Petroleum, Beijing, Changping 102249, P. R. China