hollow core

基本解釋

The riser’s inner hollow core (a pipe within a pipe) is reserved for the drill string.
立管內(nèi)部核心是空心的（管中管），留給鉆柱使用。
The core of the propellant is hollow and it burns out from the middle so that the gas accelerates through the hollow core out of the back of the solid rocket booster.
推進劑的內(nèi)核是中空的，它從內(nèi)部中間開始燃燒以至于氣體加速流過中空的內(nèi)核而從固體火箭推進器的后端噴出。
Simple and enormous intersecting walls give a balanced symmetry but are also the means by which the structure stands at the height of a 14-storey building, with an entirely hollow core.
簡單而巨大的相交墻賦予了平衡的對稱性，但也意味著結(jié)構(gòu)具有14層高建筑物的高度，具有完全空心的核心。

Despite Ahmadinejad's success in maintaining his grip on power, it is an indisputable fact that regime opponents succeeded these past few weeks as never before in destabilizing the regime and in demonstrating its hollow core.
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