According to feather element tree, the base level and base coordinate system are created, then we can choose them when we need them at any time.

根据特征元素树创建了基准面和基准坐标系，使我们很方便的在需要参照基准的时候来选取它。

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Base on the crystal-field theory, all of the crystal-field potentials of 32point-group are given for family iron ions and the relationships of which with different coordinate-system are studied.

基于晶体场理论，系统地给出了铁族离子32个点群的晶场势，并研究了坐标系取法不同时晶场势的变化。

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