youdao

A sundog is another atmospheric optical phenomenon caused by the refraction of sunlight by tiny ice crystals in clouds.

幻日是阳光通过云层中微小冰晶的折射而造成的另一种大气光学现象。

youdao

They then cascaded the negative index medium with a positive refractive index medium so that the complete nanostructure behaved as one with an index of refraction of zero.

他们将负折射率材料和正折射率材料级联起来成功实现了零折射率行为的纳米结构。

youdao

The flash itself is actually a second image of the sun, caused by refraction of its light through the layer of air closest to the sea.

ECONOMIST: In a flash

This refraction eliminates both the red end of the spectrum (red light is not bent enough by the air layer to form part of the second image) and the blue frequencies (which are scattered away: this selective scattering is why the sky is blue).

ECONOMIST: In a flash

Wave refraction: process by which the direction of approach of a wave changes as it moves into shallow water.

UNESCO: L O S S A R Y