一种在水或溶剂中不能溶解的物质。

A substance that will not dissolve in water or solvent.

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一般来说，金子和石头都不能溶解于水。

Generally speaking, neither gold nor stone are soluble in water.

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另外，不能溶解的残留物可以通过物理切除的方法来取样。

Additionally, residues that are "dried out" or are insoluble can be sampled by physical removal.

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And that's all that's big enough to pass through or small enough to pass through. And if we go up even just one row on the periodic table to potassium, what we actually see is now that it's going to be too large, and, in fact, a potassium solvated with one water molecule won't go through our channel.

就是这样刚好大到它通过,或者说刚好小到它通过,即使我们再沿着周期表往下走仅仅一行到钾离子，我们看到的就将是它的个头太大了，实际上，溶解于一个水分子的单个钾离子,不能穿过我们的通道。

麻省理工公开课 - 化学原理课程节选

Now, sodium and potassium don't ordinarily move across membranes, they're charged molecules, they can't dissolve, they can't permeate through a cell membrane, but they go through because there are channels that allow them to pass through in the membrane.

钠和钾通常是不能跨过细胞膜的,它们都是带电粒子,它们不能溶解在细胞膜中,不能渗透通过细胞膜,但它们之所以能通过细胞膜,全赖膜上离子通道的作用

耶鲁公开课 - 生物医学工程探索课程节选