Now, when light enters glass, it's a different refractive index, so it actually bends the light.

，当光线进入玻璃时，因为它的折射率不同，所以它际上会弯曲光线。

This substance has a high refractive index, meaning the speed of light passing through it is greatly reduced.

这种物质的折射率很高，意味着光穿过它的速度会大幅降低。

To combat this rain visibility problem, 3M actually developed these elements, which are retroreflectors that have different refractive indices.

为了解决雨天能见度的问题，3M 公司际上开发了这些元件，它们是具有不同折射率的逆反射器。

And on this side, we have elements that have a 2.4 refractive index and work better in wet conditions.

而另一侧，我们有折射率为 2.4 的元素，它们潮湿条件更好。

So on this side, we have elements that have a refractive index of 1.9, and they work well in dry conditions.

这一侧，我们有折射率为 1.9 的元素，它们干燥条件良好。

So where the retroreflectors act ideally under dry conditions, as soon as water is on top of them, their refractive index is lowered by a ratio of 1.33.

因此，当反射器干燥条件理想工作时，一旦水覆盖其上，它们的折射率就会降低到 1.33 的比例。

Some have the regular glass beads on them, and other ones have the 3M elements on them with the 1.9 refractive index or the 2.4 refractive index or a combination of those.

有的上面有普通的玻璃珠，有的上面有折射率为 1.9 或 2.4 的 3M 元件，或者是它们的组合。

" In addition, refractive index can also be used to 'invisibility', for example, objects with high borosilicate glass materials can also be 'invisible' when moving in glycerol with a refractive index close to its own, " Chu noted.

“此外，折射率也可以用来‘隐形’，比如高硼硅玻璃材料的物体折射率接近自身的甘油中运动时也可以‘隐形’，”褚指出。

This is actually one of the principles of realizing the " invisible cloak" , when the fabric of a garment and the air refractive index are the same, people can be freely " invisible" after wearing it, said the expert.

这位专家说，，这其也是 “隐形斗篷”的原理之一，当一件衣服的面料与空气折射率相同时，人穿上后就可以自由 " 隐形" 。