The high expandability and low permeability of these materials led to the modification of the available experimental techniques and to the design of new equipment.
由于膨润土具有较高的膨胀性以及低渗透性，因而必须对传统的试验技术进行改进，并设计出新的试验设备。
2
High Pressure Densometers are the accepted standard for measuring the porosity, air-permeability or air-resistance of materials having low permeability.
高压透气度测试仪经检验合格产品，用于测量低透水性材料的孔隙度、透气度和气阻。
3
Influence factor for the high-permeability alloy are studied in this paper. Employing reasonable control process for heat treatment technology, the magnetic properties of materials were improved.