计算机基础 a03-basic computer application; basis of computer engineering, computer basis; computers for learning; fundamentals of computing; introduction to computer
Yg - 80a construction drilling rig is a full hydraulic operated top drive power head drill . it is used to drill heavy duty pretension anchor hole at side slope of water power station , railway or highway projects , as well as drainage holes Yg - 80a型锚固工程钻机是在yg - 80钻机基础上研制的,科学分配钻机性能参数,使钻机更适合岩石潜孔锤钻进跟管钻进,同时兼顾土层合金回转钻进螺旋钻进工艺。