来自《耶鲁大学开放课程：生物医学工程探索 第21集 第21集》
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not only on the atom that you're stimulating,它不仅与你激发的原子有关 -
hydrogen in this case,在这个例子中就是氢原子 -
but the microenvironment or local surrounding还与原子周围的微环境 -
that the atom finds itself in.或原子自身的位置有关 -
If you talked about this in chemistry,如果在化学领域来谈这个问题 -
you might talk about distinguishing different hydrogen ions就会讲到用这种方法来区分 -
that are associated with乙醇上的氢原子和 -
an alcohol molecule or with a benzene ring,苯环上的氢原子 -
and how ones that are in different positions on the molecule实际上 在一个分子不同位置上的氢原子 -
will actually respond differently,也会产生不同的响应 -
give you what chemists call different chemical shifts.化学家将之称为化学位移 -
It's that same phenomenon在这里用来产生图像的方法