If the glass were kept hot enough, it would flow over the molten tin until the top surface was also flat, horizontal and perfectly parallel to the bottom surface.

如果玻璃保持足够的温度，它就会在熔化的锡中流动，直到顶部表面也变得平整、水平，与底部表面完全平行。

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The bottom surface (5) is designed to contact a handle (b).

该底面(5)设计用于与手柄(B)接触。

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A top surface and a bottom surface are defined on the base plate.

该基板上定义一顶表面和一底表面。

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If they hit the bottom surface before passing through, they are reflected off and absorbed at the top - and thus are not detected at the other end of the plates.

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On the bottom side, the notebook is sealed in such a way that you can't easily get at the battery, SSD or RAM. (This is pretty typical for Ultrabooks.) That bottom surface is also where you'll find the speaker strip, which is somewhat unusual: laptop speakers are usually located in the keyboard area or around the sides.

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Because cold water releases more CO2 into the air than warm water, the rate at which bottom water rises to the surface has a profound effect on the atmosphere above.

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