Piyang Liu
School of Civil Engineering, Qingdao University of Technology, Qingdao 266520, P. R. China;
China

Kai Zhang
School of Civil Engineering, Qingdao University of Technology, Qingdao 266520, P. R. China; School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, P. R. China;
China

Jun Yao
School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, P. R. China;
China