concaver

1.A concave mirror would project a real inverted image of the silverpoint onto the panel, which van Eyck would trace.

凹面镜把颠倒投射到木板上，于是范艾克便可以在板子上描画。

2.As a practical example, an astigmation corrected scanning flat holographio concave grating (SFHCG) is designed and some results of the numerical and optical experiments are given.

给出一消散SFHCG设计例用这块光栅所做验结果。