The Commerce Department ruled today that the Chinese are dumping crystalline silicon photovoltaic cells on the U.S. market at artificially low rates and deemed that new tariffs are needed to help level the playing field for American manufacturers. The mandatory respondents in the investigation -- the Chinese companies Wuxi Suntech Power Co. Ltd. and Changzhou Trina Solar Energy Co. Ltd. -- were hit with 31.22 percent and 31.44 percent duty rates, respectively.