This impervious layer or boundary will retard the free diffusion of moisture. This condition is referred to as case hardening.
这一不透气的壳层(或边界层)会阻滞水分自由扩散，这种情形称为表面硬化。
2
When various manipulations disturb the thermal boundarylayer inside or the condensate film and gas-vapor diffusion layer outside, the heat transfer effect will be better or be worse off.
各种操作条件只有影响到管程的温度边界层或壳程的冷凝液膜层和气-汽扩散层，才能强化或恶化传热过程。
3
Our proof of the convergence is based on an asymptotic diffusion expansion and requires error estimates on a matched boundarylayer approximation to the solution of the discrete-ordinate method.