The model with random tube net structure is used to analyses the penetrating coefficient of soil theoretically.

应用土壤的随机管子网络结构模型，从理论上对土壤的渗透系数进行了分析。

Cultivation flat roof for PE tube net cage offered references for reforming and replacing traditional net cage, and upgrading cultivation facilities.

PE管网箱养鱼平台可为改造和替代传统网箱，养鱼设施技术升级提供借鉴。

The former was deduced by the natural small basin, but it is not being considered the underlying surface change and different drainage tube net system.

前者是根据天然小流域导出的，对城区因下垫面的变化及排水管网系统的差异，采用该方法显然不十分合适；