Electric current gradient process was a new technique for testing the external coatings of the underground pipelines.

电流梯度法是一种地下管道外防护层检测的新技术。

youdao

Electric current gradient process was a new technique for testing the external coatings of the underground pipelines.

电流梯度法是一种地下管道外防护层检测的新技术。

youdao