Affiliation: | ZHOU Zhenggan1,*,NI Xiansheng 1,WEN Xiongwei2,and LI Luming2 1 Institute for Nondestructive Testing and Mechatronics Engineering,Beihang University,Beijing 100191,China 2 Tsinghua Space Center,Tsinghua University,Beijing 100084,China Received March 23,2010,revised February 24,2011,accepted March 2,published electronically November 20 |