He then went to Japan for four years to study economic management .
Then he was a postgraduate student at Harbin Engineering University from August 1988 to August 1990 , and from September 1990 - September 1993 doctoral student at East China University of Science and Technology .
student then went to Japan for four years to study economic management .
Then he was a postgraduate student at Harbin Engineering University from August 1988 to August 1990 , and from September 1990 - September 1993 doctoral student at East China University of Science and Technology .