Address: Department of Astronomy,

                            Peking University

                             Zhong Guan Cun, Hai Dian Qu

                             Beijing 100871

Email:  liuxw[put at here]bac.pku.edu.cn

www:        http://vega.bac.pku.edu.cn/~liuxw

Telephone:             (010) 6275 7870

FAX:             (010) 6276 5031