There's the hard sphere. It wants to collide against the wall to create a force on the wall, and I have a couple of the hard spheres that are nearby, right, and in the absence of any interactions, I get a certain pressure.

给墙一个作用力,现在它的附近，还有许多小球,没有相互作用时,它将直接冲向这面墙。

麻省理工公开课 - 热力学与动力学课程节选

OK, that's the hard sphere volume of the spheres.

有着相互作用力。

麻省理工公开课 - 热力学与动力学课程节选

Good data underlies the ability of managers to improve operations, innovators to devise better solutions, and funders to reward superior performance, and good data is hard to come by in the nonprofit sphere.

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But it seems musicians are still flexing their muscles in the political sphere, only the protest comes dressed in different clothes, with a new hard-nosed approach that matches the nous of politicians.

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