LUO Meiqing CHEN Nianyi Shanghai Institute of Metallurgy,Academia Sinica,Shanghai,ChinaYU Zhizhong Shanghai Institute of Testing Technics,Shanghai,ChianNING Yuantao ZHOU Xinming Kunming Institute of Precious Metals,Kunming,China CHEN Nianyi,Professor,Shanghai Institute of Metallurgy,Academia Sinica,Shanghai 200050,China