A concave mirror would project a real inverted image of the silverpoint onto the panel, which van Eyck would trace.
凹面镜把颠倒的像投射到木上,于是范艾克便可以上描画。
Dicyano 9,10 dihydro 9,10 ethenoanthracene(4) was synthesized by addition reation of acetylenedinitrile and anthracene. Concave tetrazaporphyrin has been obtained from the four molecules of 4.
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.