The test, also known as MRI, involves studying the magnetic signals from all the cells in the body.

VOA: special.2009.01.06

it's this paper mend with a plastic cover and there's all these black magnetic particles here.

它是用这种纸以及一种塑料覆在上面,这里还有一些黑色磁性粒子。

哈佛公开课 - 计算机科学课程节选

For example, one of the experiments we do is measure the magnetic field of current coil, and after we do the experiment, we all have a passive visualization that shows the same experimental set-up, except we add to that.

比如，我们做的一个实验就是,测量电线圈的磁场，在我们做完实验之后，我们都感受到了一个直观化的过程,它展现了同样的实验过程，只是那是我们加的。

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