And, I'm going to have to explain to you, where does it come from? OK, but before I do that, well, let me point out actually that the equation is not just the diffusion equation.
给你们解释一下，这个从哪儿来？，在我解释之前，告诉大家，这个方程不只是扩散方程。
2
Diffusion is when you have a fluid in which you are introducing some substance, and you want to figure out how that thing is going to spread out, the technical term is diffuse, into the ambient fluid.
扩散就是，当在某液体中加入某物质时，想算出该物质怎样在周围的液体中散开，专业术语叫做扩散。
3
Countries with policies preventing their diffusion lost out.