用两种物质标定NaOH溶液的浓度(单位为mol∙L-1)得如下结果: A、0.09785,0.09790,0.09710,0.09895 B、0.09710,0.09795,0.09785,0.09700,0.09705 试问这两组数据之间是否存在显著性差异(P=95%)?
控制冷却水大、小循环方式的部件是()。 ["A、水泵","B、温度表","C、节温器","D、水套"]
交通标志中用黄色做安全色,黑色做对比色的含义是()。 ["A、禁止标志","B、指示标志","C、警告标志","D、辅助标志"]
脉流牵引电动机大都采用()固定结构。
TXP7型平波电抗器绕组采用()式。
牵引电机相邻换向片片间用()绝缘。