National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [10975054, 91021011, 11004069]; Doctoral Foundation of the Ministry of Education of ChinaMinistry of Education, China [20100142120081, 200804870051]; Innovation Foundation from Huazhong University of Science and Technology [2010MS074]; National Basic Research Program of ChinaNational Basic Research Program of China [2012CB922103]