Complex sentence: After a post-doctoral fellowship at the Laser Spectroscopy Facility of The Ohio State University, he joined Howard University in 1988, and was a Visiting Scholar in 1990 at Northwestern University in Evanston, IL.
Split into simpler sentences: After a post-doctoral fellowship at the Laser Spectroscopy Facility of The Ohio State University, he joined Howard University in 1988. He was a Visiting Scholar in 1990 at Northwestern University in Evanston, IL.