Complex sentence: Schwab joined the U.S. National Security Agency in 2000 and led a group to study the quantum limits of mechanical structures, during which time he was named as a promising young innovator by Technology Review.
Split into simpler sentences: Schwab joined the U.S. National Security Agency in 2000, and lead a group to study the quantum limits of mechanical structures. During which time he was named as a promising young innovator by Technology Review.