为精细化表征低温液氮作用下的煤体孔隙结构,运用氮气吸附法与压汞法,针对褐煤、烟煤和无烟煤3种煤阶,进行液氮冻结处理煤样的孔隙测试和分析.通过孔径分布和比表面积分布2个参数描述液氮冻结前后煤体孔隙结构的变化.实验结果表明,经过单次液氮冻结180 min后,在同一压力下,3种煤体氮气吸附量增加,进汞量增加;3种煤体孔隙的孔径增加.研究得出,单次液氮冻结180 min后,3种煤体的孔径和孔容出现增加,比表面积出现减少;单次液氮冻结处理对不同煤体作用效果不同,褐煤孔容增加最为明显,增加了0.0178 cm3/g,烟煤孔容增量仅为褐煤孔容增量的35.4％.无烟煤比表面积减少了0.0008 cm3/nm/g,分别为褐煤和烟煤比表面变化量的2.67倍和1.6倍.高阶煤体微孔发育程度高于中低阶煤体,经过单次液氮冻结180 min处理,煤体孔隙结构改变明显.

Safety information is very important for preventing and controlling accidents,safeguarding systems and personnel safety.The degree of safety information cognition and use will affect the safety of system.In order to reveal the essence of safety information and explore the mechanism of safety information transformation,combination the research results of information phi-losophy and information science to study the essence and transformation of safety information.A safety information transformation model was proposed and a fuzzy comprehensive evaluation of the safety information transformation process was conducted.The re-sults indicate that the specific safety information ability is the primary factor to affect the safety information transformation.

This article has analyzed the relationship among influential factors for emergency capability of coal mine from four stages,namely prevention,preparation,response and recovery.Combined with examples and by using structural equation model method,the authors have studied the relationship between the influential factors of the emergency rescue capability;the result has shown that various factors have different influential ways and influential degree on the emergency rescue of the coal mine.Based on this point,this article has put forward the measures of enhancing the coal mine's emergency rescue capability.The research is of great theoretical significance for boosting coal mine enterprises' emergency rescue capability.

神华宁夏煤业集团羊场湾煤矿6.2 m大采高工作面煤层倾角达8°～20°,走向起伏角为8°～12°;其工作面赋存条件之复杂在国内外大采高开采领域很少见.根据工作面生产布局和开采现状,综合考虑了设备因素、经济因素及安全等因素.通过建立长度优化力学模型并运用非线性规划法和工程类比法手段初步对大采高工作面长进行了论证和分析.结果表明,大采高工作面最佳优化长度在经济上存在的合理值并非越大越好,在采高为6.2 m的条件下,工作面长度选取300 m较为合理.