竖直向下为重力所指方向。
气流是竖直向下的 airflow is vertically downward ; Vertical downward flow is ; Air flow is vertical down
反应物在初始阶段因高速旋转盘的牵引力被竖直向下地泵入，然后偏斜形成一个与衬底片托盘平行的流动区域。
The reactants are initially pumped vertically downward by the viscose drag force of the high speed rotating disk, and then are deflected to form a flow region that is parallel to the wafer carrier.
从而法向量的方向是竖直向上或向下的。
The normal vector is just sticking straight up or straight down.
研究结果表明：在竖直通道中，冷热流体在密度锁内形成的密度分层能抑制热量向下传递；
The result indicates that: density stratification in density lock formed by hot and cold fluid can prevent heat transfer downward in the vertical channel;
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