1. Liaoning Key Lab of Petroleum and Chemical Engineering, Liaoning Shihua University, Fushun Liaoning 113001,P.R.China;
2. College of Chemisty & Chemical Engineering, China University of
Petroleum (East China), Dongying Shandong 257061,P.R.China;
3. Department of Biochemistry, Fushun Normal College, Fushun Liaoning 113006, P.R. China