什么叫水电站的静水头?什么叫净水头?
参考答案:
水电站上、下游水位之差,称为水电站的静水头。静水头减去水电站的水头损失,即作用在水轮机上的工作水头称为净水头。
_____ 500g of honey, a single bee would have to make about 10 million trips from the hive to the flower and back again.
A Producing B To produce C Being produced D Having produced
效标与测验分数之间的相关,用皮尔逊积差相关系数的前提是假设两个变量的关系是()的分布。
A.线性
B.非线性
C.抛物线
D.正态曲线