作者机构:[1]College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001, China
相关基金:Project supported by the National Natural Science Foundation of China (Grant No. 50376012).Acknowledgements This work was supported by the Scientific Research Foundation of Harbin Engineering University (Grant No. HEUFT07066). The authors would like to thank Prof. Sun Zhong-ning for the helpful discussions and Dr experiments. The authors reviewers for giving useful manuscript. Luan Feng for his help in are also grateful to the suggestions to improve the