问题 计算题

S195型柴油机的部分技术规格如表所示:

气缸数气缸直径额定功率转速燃油消耗率冷却方式
195mm8.8KW2000R/min0.27kg/KW?h蒸发水冷

其中,“额定功率”是指柴油机正常工作时对外所做机械功的功率;“燃油消耗率”是指柴油机正常工作时,每输出1 kW·h的能量柴油机所消耗柴油的千克数。已知柴油的热值为3.3×107J/kg,水的比热容为4.2×103J/(kg·℃)。(1) 若柴油机的水箱中贮有10kg冷却水,当水的温度由20℃上升到40℃时,这些水所吸收的热量是多少焦? (2) 已知柴油机的效率η=100%(式中W为柴油机在某段时间内对外所做的功,Q为它在这段时间内所消耗的柴油完全燃烧所产生的热量),则该柴油机正常工作时的效率约为多少? (3)柴油机工作时,柴油燃烧所产生的内能,部分用于推动活塞做功,还有相当一部分热能损失,你知道有哪些形式的损耗吗?

答案

(1) 840000J 

(2)40% 

(3)散热损耗、机械损耗、废气损耗等

阅读理解

阅读理解

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                                              You choose to be a winner!

     The Winners Club is a bank account specially designed for teenagers. It has been made to help you

better manage your money. The Winners Club is a transaction account(交易账户)where you receive a

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     It's a club with impressive features for teenagers:

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    You're no millionaire so we don't expect you to pay large fees. In fact, there are no account keeping or

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     You want your money to grow. The Winners Club has a good rate of interest which gets even better

if you make at least two deposits(储蓄)without taking them out in a month.

     Convenient

     Teenagers are busy-we get that. You may never need to come to a bank at all. With the Winners

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1. The Winners Club is a bank account intended for _______.

A. parents  

B. teenagers

C. winners 

D. adults

2. Which of the following is TRUE about the Winners Club?

A. Special gifts are ready for parents.

B. The bank opens only on work days.

C. Services are convenient for its members.

D. Fees are necessary for the account keeping.

3.The Winners Club provides magazines which ________.

A. encourage spending

B. are free to all teenagers

C. are full of adventure stories

D. help to make more of your money

4. If you want to be a member of the Club, you must ________.

A. be an Internet user

B. be permitted by your parent

C. have a big sum of money

D. be in your twenties

5. What is the purpose of this text?

A. To set up a club.

B. To provide parttime jobs.

C. To organize keycards.

D. To introduce a new banking service.

问答题 简答题