Raw samples of oleanolic and ursolic acids, a class of terpenoid acids mainly found in the leaf and fruit cuticles of some plant species, can be defined as a blend of clusters of different conformers aggregated in dimers and tetramers by means of hydrogen bonds and stabilized by non-electrostatic interactions.

中文翻译：

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齐墩果酸和熊果酸的结构测定：组合密度泛函理论/振动光谱方法

齐墩果酸和熊果酸的原始样品是一类主要存在于某些植物物种的叶和果实角质层中的萜类酸，可以定义为通过氢键聚合成二聚体和四聚体的不同构象异构体簇的混合物，并通过非静电相互作用。