未冻结的海水盐度一般为()。 ["10~15","15~25","20~35","25~30"]
简述27.5kv母线失压后的各种异常现象?
砖砌体水平缝的砂浆饱满度应不低于() ["50%","80%","40%","60%"]
检查灰缝砂浆饱满度的工具是() ["锲形塞尺","方格网","靠尺","托线板"]
下列有关纵隔畸胎瘤的表述错误的是()。 ["治疗以外科手术为主","为良性肿瘤","X线典型表现为前下纵隔向一侧生长的圆形或椭圆形阴影,有时呈分叶状;多数边缘清晰,常可见囊壁钙化或不规则骨骼影","常见的症状有胸闷、胸痛、咳嗽、气促及心悸等","易发生继发感染"]
简述在变电所正常倒闸操作时断路器拒动的处理措施?