U.S. trade officials have proposed tariffs of about 31% on solar panels imported from leading producers in China, saying Chinese companies are selling their products at less than fair value in the U.S. The tariffs, slated to become final in October, would affect more than 61 companies in China. Trade officials say the move is intended to protect the U.S. market. However, Dow Corning president and CEO Robert Hansen, and Andrew Tometich, president of Hemlock Semiconductor Group, say the duties will have the opposite effect.