引入空间群消光规律，用计算机模拟电子衍射图，提出选取约化四边形的新方法。

Adopting the space-group extinction rule and simulating the electron diffraction pattern with computer, this paper proposed a new method for selecting the reduced quadrangle.

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定义两种描述高斯光束被硬边光阑弱衍射的远场下的光阑ABCD矩阵。

Two ABCD matrices for describing hard apertured Gaussian beams weakly diffracted in the far field are defined.

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然后我们再做微小的调整，到焦点的另一边轻微散焦后，看衍射圈质量是否有明显的提高。

Then I make a micro adjustment and go to the other side of focus and see if it has gotten better or worse for that side.

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