The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that substantial portions of the text came from other published papers. The scientific community takes a very strong view on this matter, and the Journal of power and Energy Engineering (JPEE) treats all unethical behavior such as plagiarism seriously. This paper published in Vol.2 No.4,297-303（pages）, 2014, has been removed from this site.