The designing idea, testing principle and realization of electric circuit about the two - frequency eddy testing instrument WFL for aluminum alloy quality inspection are introduced.

论述了用于铝合金质量检测的WF L双频涡流检测仪的设计思路、检测原理和电路实现。

youdao

WfL education manager Karen Clarke said each child was assessed three times during the session for two minutes each time to analyse how they were interacting with their environment.

BBC: Boy in woods (generic)