本文讨论了物理化学中的几种研究方法，如科学抽象法、理想模型法、本质揭示法、极限外推法、相对数值法和控制变量法等。

This paper discussed a few research method about physical chemistry, such as scientific abstract, ideal mode, essential show, limit inference, relative number, variable control and so on.

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此外，还引入集群类型这一控制变量，研究发现，不同集群类型中，研究模型的检验结果存在差异。

Furthermore, this paper introduces the cluster type, a control variable, through which it is found out that the testing results vary in different types of clusters.

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