They then traverse a substitution chain of element declarations or a type hierarchy to determine whether the element declaration satisfies the substitution or type derivation requirements.

然后遍历元素声明的代替链或类型层次结构，以决定元素声明是否满足代替或类型衍生要求。

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The result shows excellent selectivity of to the 1, 3 - substitution positions, and the alkyl chain may be saturated or unsaturated and may contain one or more heteroatoms.

结果显示对1,3 -取代位置的优异选择性，并且烷基链可以是饱和的或不饱和的，并且可以含有一种或多种杂原子。

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According to the principle of substitution of the generalized kinematic pair, mobility of the complex loop mechanism composed by multiple sub — chain was studied.

并依据广义运动副替代原则，得到多个子链组合而成的复杂多环路机构的自由度。

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