Some feature in phase diagram drawing is analyzes and modified quadratic fitting method is used to fit the curves. The method is proved to be effective.

本文分析了水盐体系相图中二次曲线拟合的特点，并提出使用修改后的二次拟合方法对相图中曲线进行拟合的方法，在绘制相图中得到了较好的效果。

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Note: if you select a quadratic or cubic fit, the software will automatically switch to a linear fit if less than 12 reference stars are available.

注意：若你选择了高次拟合，如果你的参考星数目小于12颗，软件将自动转换为一次拟合。

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Using the radio buttons in this section, you can set the software to use linear, quadratic or cubic fits for the plate constants. Small field CCDs usually require no more than a linear fit.

使用本类里的单选按钮，你可以选择使用底片常数的一次、二次或三次拟合。

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