direct diffusion

例句：

1. 1. The drug was found to have a direct diffusion effect on the brain.
   这种药物被发现对大脑有直接的扩散效应。
2. 2. The virus spreads through direct diffusion of genetic material.
   病毒通过遗传物质的直接扩散来传播。
3. 3. The chemical compound is known to undergo direct diffusion in polar solvents.
   这种化合物已知在极性溶剂中会发生直接扩散。