弧焊变压器是一种交流电源,根据获得下降外特性的不同方法,可将弧焊变压器分两大类:一类是(),二类是()。
参考答案:正常漏磁式弧焊变压器;增强漏磁式弧焊变压器
某化工厂生产液氨,因市场需求量增加,须进行扩建,为取得主管部门批准立项,该化工厂需要对扩建项目进行()。
A、安全预评价
B、专项安全评价
C、安全现状评价
During the winter months,the southeast trade winds are().
A.per than during the summer months
B.weaker than during the summer months
C.drier than during the summer months
D.wetter than during the summer months