【单选题】下列关于涡流的说法中正确的是
A.
涡流跟平时常见的感应电流一样,都是因为穿过导体的磁通量变化而产生的
B.
涡流不是感应电流,而是一种有别于感应电流的特殊电流
【单选题】如下关于对流传热和热对流关系的说法,正确的是()。
C.
热对流是对流传热的一种,对流传热还有别的实现方式
D.
当流体流动状况发生变化时,热对流可以发展为对流传热
【单选题】In the third paragraph, the author tries to demonstrate that our siblings
A.
offer us much useful information.
B.
have great influences on us.
C.
are the ones who love us completely.
D.
accompany us throughout our life.
【单选题】What conclusion can we draw from the passage?
A.
The author tries to tell the readers how important the language is.
B.
The author intends to explain the significance of culture in global communication.
C.
The author thinks his mistake is only an awkwardness in his everyday life.
D.
The author wants to illustrate what the sentence 'Don't use thanks' means.
【单选题】The author tries to convince us that
A.
college education paves the way for future success.
B.
higher education faces an unforeseeable future.
C.
a college diploma is the necessary credential for better jobs.
D.
the purely economic reason for college is not as compelling as it once was.
【单选题】下列关于涡流的说法正确的是
A.
涡流是感应电流,也是因为穿过导体的磁通量变化而产生的
B.
涡流不是感应电流,而是一种有利于感应电流的特殊电流
【多选题】关于总传热系数说法正确的是
A.
对于埋地管道,总传热系数可分为三部分,一与管内壁与天然气的对流换热有关,二与从管内壁到管外壁、再到防腐绝缘层这些固体材料的导热有关,三与管外层和土壤间的换热有关
C.
工程上,聚乙烯防腐层管道的总传热系数 K 范围一般为: 0.7~3W/(m2 · K) ,具体数值与管径、土壤潮湿程度有关
【单选题】In the book, the author tries to explain that
A.
money is useless to us.
B.
money is the aim of life.
C.
money should be an instrument.
【多选题】关于对流换热,说法正确的是_____。
D.
对流换热是热对流和导热两种传热方式共同作用的结果