**Author details**

Dong Duan, Haiyang Wang, Wenyu Shi and Zhanbo Sun\* School of Science, Xi'an Jiaotong University, Xi'an, P.R. China

\*Address all correspondence to: szb@mail.xjtu.edu.cn

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
