Acknowledgements
This research is founded by the National Natural Science Foundation of China (Grant No:
51008201). And this research is also sponsored by the Scientific Research Foundation for the Returned
Overseas Chinese Scholars, State Education Ministry of China. Moreover, this research is also the key
project supported by the Scientific Research Foundation, Education Department of Hebei Province of
China (Grant No: GD2010235). In addition, this research is also supported by Science and Technology
Development Program of Hebei Province of China (Grant No: 07247189D) and Society Science
Development Program of Hebei Province of China (Grant No: 201004068).