[1/2] Flags of China and U.S. are displayed on a printed circuit board with semiconductor chips, in this illustration picture taken February 17, 2023. REUTERS/Florence Lo/Illustration/File Photo June 28 (Reuters) – U.S. officials are considering tightening an export control rule designed to slow the flow of artificial intelligence chips to China by clamping down on the amount of computing power the chips can have, according to two people familiar with the matter. The Biden administration last October issued a sweeping set of rules designed to freeze China's semiconductor industry in place while the U.S. pours billions of dollars in subsidies…