This is because the current the electrodes detect is weak, and a really good contact needs to be made between apparatus and skin.

这是由于电极要探测的电流非常弱，仪器与皮肤需要非常好的接触。

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The coils in the scanning apparatus detect these magnetic changes, which are used to build up a map of the part of the body being examined.

扫描仪上的线圈探测到这些磁场变化，并以此构建出患者受检部位的图谱。

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A video automatic surveillance alarm apparatus has been developed, based on the digital image matching principle, possessing the ability to detect moving tsrget' s in a stationary scene.

利用数字图像匹配技术检测出静止场景中运动物体的原理，研制出了电视自动监视报警擒拿装置。

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He was the first to satisfactorily demonstrate the existence of electromagnetic waves by building an apparatus to produce and detect radio waves.

UNESCO: Some important dates for radio