[名词解释] 电子束焊

SF6气体去游离的速度比空气快（）倍 ["50","80","100","200"] 热喷涂焊 分级绝缘变压器在断电前（） ["应先合接地刀闸","应先将接地刀闸断开","对接地刀闸的切合无要求","先断开变压器后再将接地刀闸合上"] 电缆一般采用（）作耐压试验 ["交流","直流","脉冲电流","冲击"] 钎焊 电子束焊