什么是非接触式引弧?非接触式引弧有几种形式?常用于哪些焊接?有几个阶段?
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Fusible plugs are installed in fire-tube boilers to ().
A. provide a means of draining the boiler
B. warn the engineer of low water level
C. cool the crown sheet at high firing rates
D. open the burners electrical firing circuit
在氧气供应不足的情况下,脂肪和糖可无氧酵解生成ATP。
A. 正确
B. 错误