同位素：一种化学元素的两个或多个类型，它们的原子核具有相同的质子数，而中子数却不同。
Isotope: One of two or more species of atoms of a chemical element having nuclei with the same number of protons but different Numbers of neutrons.
单原子的结构是个基本极限：若要做得更小，基本上就得操控原子核了，这可是把一种化学元素转换为另一种。
A structure the size of an atom represents a fundamental limit: to make anything smaller would require manipulating atomic nuclei—essentially, transmuting one chemical element into another.
单原子的结构是个基本极限：若要做得更小，基本上就得操控原子核了，这可是把一种化学元素转换为另一种。
A structure the size of an atom represents a fundamental limit: to make anything smaller would require manipulating atomic nuclei—essentially, transmuting one chemical element into another.
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