They then traverse a substitutionchain 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。
2
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.
According to the principle of substitution of the generalized kinematic pair, mobility of the complex loop mechanism composed by multiple sub — chain was studied.