Josh Lederman and Ted Bridis, AP Sources: US to Impose Limits on Some Chinese Visas. Associated Press, May 29, 2018. https://apnews.com/82a98fecee074bfb83731760bfbce515
("State Department said Tuesday [May 29] * * * The changes begin June 11. * * * The State Department did not provide specifics. But a U.S. official said that according to instructions sent to U.S. embassies and consulates, Chinese graduate students will be limited to one-year visas if they are studying in fields like robotics, aviation and high-tech manufacturing. * * * The instructions also say that Chinese citizens seeking visas will need special clearance from multiple U.S. agencies if they work as researchers or managers for companies on a U.S. Commerce Department list of entities requiring higher scrutiny")
My comment: All Chinese students used to received a single-entry, one-year student visa from US consulates. Then a couple of years ago, US and China reached a reciprocal agreement, and Chinese got a multi-entry, five-year student visa. (But the length of visa has nothing to do with the length of a legal stay, which is determined by an immigration officer at the port of entry.) Is the new direction back to the future for some fields?