Affiliation: | Liu Hao, Cao Feifei , Zhou Ning , Zou Xuecheng , Liu Dongsheng ( Henan Electric Power Research Institute, Zhengzhou 450052, P. R. China) ( "" Henan Electric Power Industrial School, Zhengzhou 450051, P. R. China) ( *'" Department of Electronic Science & Technology, Huazhong University of Science & Technology, Wuhan 430074, P. R. China) |