Chinese-American physicist Tsung-Dao Lee, who in 1957 became the second-youngest scientist to receive a Nobel Prize, has died at age 97. That's according to a Chinese university and a research center. He died Sunday at his home in San Francisco. His work advanced the understanding of particle physics. A joint obituary released by the Tsung-Dao Lee Institute at Shanghai Jiao Tong University and the Beijing-based China Center for Advanced Science and Technology says Lee was one of the great masters of the field. Robert Oppenheimer once praised Lee as one of the most brilliant theoretical physicists of the time.