permittivity of vacuum

例句：

1. 1.The vacuum in the chamber has a permittivity of 10^-6 S/m, which is very low.
   该腔室中的真空具有10^-6 S/m的介电常数，这非常低。
2. 2.The permittivity of the material can be adjusted by changing its composition or temperature.
   通过改变材料的组成或温度，可以调整材料的介电常数。
3. 3. The permittivity of materials plays an important role in determining their electrical properties.
   材料介电常数在决定其电气性质方面起着重要作用。