1. Institute of Innovation (Baotou), Peking University, Baotou 014030, PR China
2. College of Engineering, Peking University, Beijing 100871, PR China
3. The Erlian Filiale of Huabei Oilfield Company, Erenhot 026017, PR China
4. Sinopec Shengli Oilfield Xinchun Oil Production Plant, Dongying 257000, PR China