Abstract: Satety charactcristics of the ventilation system in coal mine are analyzed.Indexes for the safety assessment o文摘:分析了矿井(煤矿)通风系统的安全性，提出了评价矿井通风系统安全性的指标，确定了矿井通风系统安全性等级。
Induced Mutations of Varitety of High Yield of Flammulina Velutipes SOD by He-Ne LaserHe-Ne激光对金针菇SOD高产株的诱变效应