问题 问答题 简答题

流量量值具有哪些特点,使得各类检测参数量值传递系统中,流量的量值传递系统较困难建立?

答案

参考答案:

流量量值主要有以下特点:

(1)流量是自然界不存在实物标准的导出量,需在特定条件下由基本量(长度、质量、时间、温度等)合成;

(2)流量是一个动态量,它是一个只有当流体发生运动时才实际存在的物理量,因此它不仅是基本量的静态组合,又由于其动态性质,流量量值受到许多复杂因素的影响;

(3)流量量值需通过液体介质的物理变化得以反映,因此用于校验的介质最好就是使用介质,但介质有许多种,不可能都按此校验,有时只好采用模拟媒介,然后通过换算作为工作介质流量;

(4)存在于不同工作状态的流体介质表现出不同的物理性质,因此流量量值在不同工作状态时必须考虑该因素的影响。

阅读理解

A man came home from work late, tired and unhappy, to find his 5-year-old son waiting for him at the door.

The boy asked, "Daddy, how much do you make per hour?" The father was furious at his son's question.

When he said $20 an hour, the little boy asked his father to lend $10 to him. The father was even angrier because he thought the boy just wanted some money to buy a toy. So he didn't answer his son.

The little boy quietly went to his room. After about an hour or so, the man calmed down and started to think: Maybe there was something he really needed to buy with that $10.

"Maybe I was too hard on you just now," the man went into the room and said. "Here's the $10 you asked for." 

"Oh, thank you, Daddy!" He said. Then, he reached under his pillow, pulled out some crumpled coins and said, "Daddy, I have $20 now. Can I buy an hour of your time? Please come home early tomorrow. I would like to have dinner with you."

小题1:How much does the man make if he works 10 hours?

A.$10.

B.$20.

C.$30.

D.$40小题2:In this passage, the underlined word "furious" means ______.

A.very angry

B.quite happy

C.too excited

D.a little nervous小题3:At first, the father refused to lend the boy any money because ______.

A.he thought the boy wanted to keep the money for himself

B.he did not have enough money at that moment

C.he thought the boy would buy something of no use

D.the boy always borrowed money from him小题4:The boy wanted to buy ______ with twenty dollars.

A.a new book for himself

B.a nice present for his father

C.a toy for his own birthday

D.an hour of his father's time小题5:From the passage, we can infer (推断) that the boy's father ______.

A.often played with his son

B.spent little time with his son

C.didn’t love his son at all

D.often came back home early

综合题