几十年来，粒子物理学家们用氢原子作为基准衡量质子的大小。
For decades, particle physicists have used the hydrogen atom as a benchmark for measuring the size of protons, which are part of the core of atoms.
为了要建立反氢原子，并且要使它不至于马上湮灭，反氢激光物理装置的研究团队把反质子冷却，并把它们压缩成火柴棍大小的云斑。
To create antihydrogen and keep it from immediately annihilating, the ALPHA team cooled antiprotons and compressed them into a matchstick-size cloud.
然后研究人员推动这个冷却的云斑，并进一步把反质子压缩，以致可以用一个相似大小的中子云来与它相重叠，就在那时，两个粒子（反质子和中子）成对地形成了反氢原子。
Then the researchers nudged this cloud of cold, compressed antiprotons so it overlapped with a like-size positron cloud, where the two particles mated to form antihydrogen.
本研究的特定目的就是去评价质子治疗与当前先进的治疗手段在治疗前列腺癌的成本效应大小。
The specific aim of this study was to examine the cost effectiveness of proton beam radiation compared with current state-of-the art therapy in the treatment of patients with prostate cancer.
质子自旋的大小总是相同的，按归惯例被设定为1/2。
The magnitude of a proton's spin is always the same and is conventionally set to be 1/2.
质子自旋的大小总是相同的，按归惯例被设定为1/2。
The magnitude of a proton's spin is always the same and is conventionally set to be 1/2.
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