()是植食性害虫。 ["蝗虫","步行虫","虎甲","蚕"]
()是捕食性昆虫。 ["蝗虫","步行虫","小地老虎","蚕"]
()是昆虫最前面的1个体段。 ["胸部","腹部","头部","体壁部"]
昆虫的头部一般由()个体节愈合而成。 ["3","4","5","6"]
已知在型钢轧机上热轧,轧辊线速度〈2.5m/s,轧辊工作直径为550mm,咬入角为23度,求允许最大压下量?(cos23=0.92)
已知在型钢轧机上热轧,轧辊线速度〈2.5m/s,轧辊工作直径为500mm,咬入角为25度,求允许最大压下量?(cos25=0.91)