Objective: To study clinical importance of casting pile-core crown with negative pressure suction silastic impressions and analyze reasons for the failure of routine impressions in pile-core crown.
目的：探讨铸造桩核冠常规印模过程中失败的原因，研究负压抽吸硅橡胶印模应用于铸造桩核冠的临床意义。
The density of Manchurian linden and the tree-crown -nesting birds shows the conspicuous negative correlation.
椴 密度与树冠营巢鸟类的种类存在显著负相关关系。
The POD activity have a strikingly negative relationship with the height of tree, trunk girth, diameter of crown, the volume of the tree crown, and the dwarfed nature of the stocks.
POD活性与树高、干周、冠径、树冠体积呈显著负相关，与砧木的矮化性呈负相关。
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