BEIJING (AP) — Treasury Secretary Janet Yellen has criticized China’s treatment of U.S. companies and new export controls on metals used in semiconductors during a visit to Beijing to try to revive strained relations. Speaking with businesspeople, Yellen defended U.S. controls on technology exports that irk Beijing, saying they’re necessary for national security. She rejected suggestions Washington is trying to decouple the U.S. economy from China’s. Yellen cited what she said was China’s use of subsidies to state-owned industries and barriers for foreign competitors. U.S.-Chinese relations are at their lowest level in decades due to disputes over technology, security, Beijing’s military expansion and other irritants. Treasury officials said no major breakthroughs were expected.