1. In simple tension experiment, the stress-strain relationship submits Hook's law within the limit of proportionality. 单向拉伸试验中，在比例极限内，应力应变关系服从胡克定律。
2. The proportionality constant, H, is known as the Hubble constant and quantifies how fast space is stretching—not just around us but around any observer in the universe. 其中的比例常数H，就是所谓的哈伯常数，它可以把空间向外延伸的快慢予以量化，不只针对我们周遭，也适用于宇宙中所有观测者的周围。
3. This value is used to compare the strength of materials, but a safety factor is applied when making design calculations, to bring the working stress well below the limit of proportionality. 此值被用来比较材料的强度，但是当设计计算时，要用一个安全系数，使工作应力低于比例限制。
英英解释
n.
1. a ratio of two quantities that is constant
2. harmonious arrangement or relation of parts or elements within a whole (as in a design)
