[1] Guangxi Univ, Coll Phys Sci & Technol, Nanning 530004, Peoples R China
[2] Guangxi Prov Inst Cultural Rel & Archaeol, Nanning 530023, Peoples R China
[3] China Inst Atom Energy, Beijing 102413, Peoples R China
[4] Peking Univ, Minist Educ, Inst Heavy Ion Phys, Beijing 100571, Peoples R China
[5] Peking Univ, Minist Educ, Key Lab Heavy Ion Phys, Beijing 100571, Peoples R China
[6] Univ Naples 2, Dept Environm Sci, I-81100 Caserta, Italy