山西省煤基重点科技攻关项目MH2014-06;山西省自然科学基金项目2013011010-5;高等学校博士学科点专项科研基金项目20131401120005;Supported by the Key Coal Technologies R&D Program of Shanxi ProvinceMH2014-06,the Natural Science Foundation of Shanxi Province 2013011010-5 and the Specialized Research Fundation for the Doctoral Program of Higher Education 20131401120005.