It has been proved by some experiments focused on micro materials, which are done by Fleck, Stolken, Evans and others, that metal may be affected by size when its character length is in the level of micron.

• 一些测量小尺度材料的实验，如Fleck等人的细铜丝扭转试验，Stolken和Evans的薄梁弯曲试验都证明当非均匀塑性变形的特征长度为微米量级时，金属材料呈现出很强的尺度效应。