1. State Key Laboratory of Heavy Oil Processing, Institute of New Energy College of Chemical Engineering China University of Petroleum (East China) Qingdao 266580 China
2. Guangxi Colleges and Universities Key Laboratory of Beibu Gulf Oil and Natural Gas Resource Effective Utilization College of Petroleum and Chemical Engineering Beibu Gulf University Qinzhou 535011 China
3. College of Electrical Engineering Qingdao University Qingdao 266071 China