US Admiral Mike Mullen (left), chairman of the Joint Chiefs of Staff, and General Ma Xiaotian, deputy chief of the General Staff of the People's Liberation Army (PLA), visit the PLA Air Force base in Jining, East China's Shandong province, July 12, 2011. Mullen is in China for a four-day visit wrapping up on Wednesday when he will leave for the Republic of Korea and Japan. [Photo/Xinhua]