1. School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
2. Shaanxi Key Laboratory of Chemical Additives for Industry, College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China
3. Key Laboratory of Tibetan Medicine Research and Qinghai Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai 810001, P. R. China