Jing Tsu in Wired:
Quiet, cautious, and insistent, Zhi was also highly qualified. He earned a PhD in physics from Leipzig University but declined a job offer in the United States in order to return to China. He taught at two Chinese universities and later helped to devise China’s landmark 12-year Plan for the Development of Science and Technology of 1956. It was a hopeful time for scientists and technicians who were deemed useful for their contributing roles in a state-guided socialist economy.
Since his arrest in July 1968 for being a “reactionary academic authority,” Zhi had been cut off from his research, the news, and his devoted German wife. He was used to working on equations and engineering problems with teams of colleagues. No longer. His only company was the eight characters on the wall of his cell reminding him that prisoners faced two options from their minders: “Leniency to those who confess, severity to those who refuse.”
More here.