Wei Chen
School of Science,
North China University of Science and Technology, Tangshan 063000, China
E-mail: chenweiimu@gmail.com

Hao Lin
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Informational Biology´╝î
University of Electronic Science and Technology of China, Chengdu 610054, China
E-mail: hlin@uestc.edu.cn