undetected

They feared some undetected trace of poison.

他一些未被识破的投毒痕迹。

This heating helps to break down weak spots in the dielectric that otherwise might pass through the electrode undetected, only to fail during a later spark or hipot test.

这热量帮助击穿电线绝缘较薄的地方﹐否则线材通过电极而没有被检测到﹐结果在以后的火花测试和高压绝缘试验将会失效。