Fick laws of diffusion

Fick laws of dif·fu·sion

1. the direction of movement of solutes by diffusion is always from a higher to a lower concentration, and the diffusive flux JA of solute A across a plane at x is proportional to the concentration gradient of A at x; that is, JA = -D(δCA/δx);
2. the increase of concentration of solute A with time, δCAt, is directly proportional to the change in the concentration gradient, that is, δCAt = D(δ2/δx2).
[Adolf Fick]

Fick laws of dif·fu·sion

(fik lawz di-fyū'zhŭn)
1. The direction of movement of solutes by diffusion is always from a higher to a lower concentration and the diffusive flux JA of solute A across a plane at x is proportional to the concentration gradient of A at x; i.e., JA = -D(CA/x);
2. The increase of concentration of solute A with time, CA/t, is directly proportional to the change in the concentration gradient, i.e., CA/t = D(fl2/x2).
[Adolf Fick]