1984-1985  Teaching Assistant, Yunnan Normal University
1988-1990  Assistant Professor, Yunnan Normal University
1993-1996  Assistant Professor, Institute of Software, Academia Sinica
1996-1999  Associate Professor, Institute of Software, Academia Sinica
1999--　　 Full Professor, Institute of Software, Chinese Academy of Sciences
2000,Mar.--2002,Feb.,  Research Fellow, University of Leeds, UK.

Major Publications：
Strong decomposition theorem of the recursively enumerable degrees (in Chinese), Acta Math. Sinica, 1992, 35(2):251.
A decomposition theorem of 0', Science in China, No. 10, 1992 (in chinese) and No.6, 1993
A result about the pseudo jump operators, Bull. of Chinese Sciences, No. 21 , 1992
Cupping the recursively enumerable degrees by d.r.e. degrees (with X.Yi), Proceedings of London Mathematical Society, 3 78 (1999), 1-21.
Computability Theory (in chinese, with D. Yang), Science Press, Beijing, 1999.
A high diamond theorem, (with D. Yang), Journal of Software, 2000, 11(1):23--39.
Bounding cappable degrees, Archive for Mathematical Logic, (2000) 39:311--352.
On a Conjecture of Lempp, Archive for Mathematical Logic, (2000) 39:281--309.
A hierarchy for cuppable degrees, Illinois Journal of Mathematics, Vol. 44, No.3, 2000, 619--632. (with Wu and Zhang).
There is no low maximal d.c.e. degrees, Math. Log. Quart. 46 (2000) 3, 409--416. (with Arslanov and Cooper)
Definable relations on the computably enumerable degrees, in Computability and Models (eds. Cooper and Goncharov), Kluwer Academic/Plenum, 2002.
On the distribution of Lachlan nonsplitting bases, Archive for Math. Logic, 41, 455--482 (2002). (with Cooper and Yi)
Non-uniformity and generalised Sacks splitting, Acta Math. Sinica, 2002. (with Cooper)
Splitting and cone avoidance in the d.c.e. degrees, to appear in Science in CHINA, 2002. (with Cooper)
Turing definability in the Ershov hierarchy, Journal of London Mathematical Society, to appear. (with Cooper)
Splitting and Nonsplitting, II: A rm Low_2 Computably Enumerable Degrees Above Which 0' Is Not Splittable, Journal of Symbolic Logic, to appear. (with S. B. Cooper)

Conference Talk：
One hour, International Conference on Math. Logic and Applications dedicated to A. I. Mal'tsev and the 275th Anniversary of the Russian Academy of Sciences, Novosibirsk, Aug. 10--15, 1999.
45 minuites, International Conference on Mathematical Logic-- Satellite Conference of ICM Beijing 2002, and the 8th Asian Logic Conference, Chongqing, Aug. 28--Sept. 3, 2002.
15 minuites, Structural Threory of the Computably Enumerable Turing Degrees,
ICM 2002, Beijing, 20--28, Aug.