College of Science, Hebei Polytechnic University, TangShan, China
Information Center, North China Coal Medical University, TangShan, China

Copyright © Li Liu, Jun-dong Zhu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

How to Cite this Article

Download citation as EndNote