At the same time displacement compressor chooses big purchase cost is higher.
同时选用大排气量压缩机的购置费用较高。
2
The constitutive laws of joint material and block material can be fully considered in the model. The cost of computation is low. It is a discontinuous element for displacement.
该模型能充分考虑节理裂隙材料和块体材料的本构关系，计算量不大，是一种位移不协调单元。
3
Under the former mode, the cost of developing the shallow sea oilfield is very high. The long displacement well drilling technology is an effective way to solve this problem.