Complex sentence: In 1974 he joined the University of Vienna as assistant professor, but returned to UIUC as a Visiting Associate Professor in 1977 where he worked on batch-coupled devices and developed the concept of Real Space Transfer with Ben G. Streetman Space Transfer Transistor, RSTT.
Split into simpler sentences: In 1974 he joined the University of Vienna as assistant professor. Hess returned to UIUC as a Visiting Associate Professor in 1977 where he worked on batch-coupled devices and developed the concept of Real Space Transfer with Ben G. Streetman Space Transfer Transistor, RSTT.