1. Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, College of Bioresource Chemical and Materials Engineering, Shaanxi University of Science & Technology, Xi’an 710021, P. R. China
2. Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University, Xi’an 710072, P. R. China
3. School of Electrical and Control Engineering, Shaanxi University of Science & Technology, Xi’an 710021, P. R. China
4. School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710021, P. R. China