基金项目: | Acknowledgements This work was financially supported by the National Natural Science Foundation of China (Nos. 11005088 and 11105115), the Project of Basic and Advanced Technology of Henan Province of China (No. 112300410021), the Key Project of Henan Educational Committee (No. 12A140010) and the Young Teacher's Program of Xinyang Normal University (No. 2011084). The authors are grateful to Prof. M.A. Blanco and his colleagues for their Gibbs code. |