1. Yunnan Normal University, 768 Jvxian Street, Kunming, Yunnan 650500, PR China
2. Yunnan Research Center of Biogas Technology and Engineering, School of Energy and Environment Science, Yunnan Normal University, 768 Jvxian Street, Kunming, Yunnan 650500, PR China
3. Yunnan Yunyu Technology Co., LTD, Kunming 650117, PR China