Complex sentence: After being discharged in 1946, Colgate returned to Cornell University, where he completed a Bachelor of Science in 1948 and a PhD in nuclear physics in 1951, then taking up a position as postdoctoral fellow at Berkeley.
Split into simpler sentences: After being discharged in 1946, Colgate returned to Cornell University. He then completed a Bachelor of Science and a PhD in nuclear physics, taking up a position as postdoctoral fellow at Berkeley.