Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger 题目和参考答案——青夏教育精英家教网—

题目内容

Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri(MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

“To provide enough power, we need certain methods with high energy density(密度)”, said Jae Kwon, assistant professor of electrical and computer engineering at MU. “The radioisotope(放射性同位素) battery can provide power density that is much higher than chemical batteries.”

Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro / nanoelectromechanical systems (M/NEMS). Although nuclear batteries can cause concerns, Kwon said they are safe.

“People hear the word ‘nuclear’ and think of something very dangerous,” he said, “However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems.”

His new idea is not only in the battery’s size, but also in its semiconductor(半导体). Kwon’s battery uses a liquid semiconductor rather than a solid semiconductor.

“The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure of the solid semiconductor,” Kwon said, “By using a liquid semiconductor, we believe we can minimize that problem.”

Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery. In the future, they hope to increase the battery’s power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.

1.Which of the following is true of Jae Kwon?

A. He teaches chemistry at MU.

B. He is working on a nuclear energy source.

C. He developed a chemical battery.

D. He made a breakthrough in computer engineering.

2.Jae Kwon gave examples in Paragraph 4_________.

A. to introduce nuclear batteries can be safely used

B. to show chemical batteries are widely applied

C. to introduce various energy sources

D. to describe a nuclear-powered system

3.Liquid semiconductor is used to _________.

A. get rid of the radioactive waste

B. test the power of nuclear batteries.

C. reduce the damage to lattice structure.

D. decrease the size of nuclear batteries

练习册系列答案

相关题目

China dropped its decades-long, one-child policy last year to allow each family to have two children. This change has put 270 million married women of childbearing age in the position of choosing between family and work. The employers also face big challenges as more female workers will have two maternity leaves(产假) for a total of seven to eight months.

In a survey published by classified advertising website Ganji.com, career women who might be considering having a second child were asked what kinds of pressure they might expect. More than 76 percent of the women who were questioned mentioned concerns about the financial burden of raising two children, while more than 71 percent said it would be difficult to balance career and family. In addition, nearly 56 percent said that having a second child would definitely have a negative effect on their career.

Another survey conducted by Chongqing-based human resources website job.cq.qq.com found that over 70 percent of job seekers believe that having a second child would make females less popular in the job market, although two-thirds of the employers said the policy will make no difference in their employment of staff.

Feng Lijuan, s senior expert on human resources at 51 job.com, a leading Chinese job finding platform, said she would not say “there is prejudice against career women.” Feng said Chinese women shoulder more family responsibility. “It is not only about maternity leave; a female employee might only fully get back to work after three to five years after having her first child.”

Wang Yixin, a senior employment adviser, said the positive side is that more companies are trying to attract more talents by providing support to career women. “Different from before, it is not only employers choosing employees. Many talents, including professional career women, also choose employers.” said Wang. “According to our survey, many large companies are very open to their employees’ choice of having a second child.”

1.Women employees take longer time to concentrate on work after childbirth because .

A. there is more prejudice against career women

B. they have longer maternity leaves to enjoy

C. they shoulder more family responsibility

D. having a second child makes them less popular

2.What are women concerned about when having two children in the first survey?

①Financial burden of raising two children

②Fewer opportunities to get a pay rise

③Negative effects on their career

④Difficulty in balancing career and family

A. ①②③ B. ②③④

C. ①②④ D. ①③④

3.Which of the following shows the structure of the whole text?

(P: Paragraph)

A. B.

C. D.

4.Which is the best title for the passage?

A. Disadvantages of Raising Two Children

B. Responsibilities of Career Women

C. Effects of Two-child of Policy on Women

D. Attitudes of Employers to Women

5.According to the second survey, having a second child would .

A. have no effect on career women

B. have a positive effect on career women

C. have a negative effect on career women

D. have both positive and negative effects on career women

________ his age, he still leads an active life.

A. Though B. Because of

C. In spite of D. In addition

On the day the tornado hit,there was no indication that severe weather was on its way—the sky was blue and the sun bad been out.The first alert my husband,Jimmy,67,and I,65,got came around 9 p.m.,from some scrolling text on the TV Jimmy was watching.He ran upstairs to find me in our third-floor bedroom,and we changed the channel from the presidential primary debate I had been watching to our local Pensacola,Florida,station.

No sooner had we found coverage of the tornado than it was on top of us.It was the loudest thing I have ever heard.The bones of the house shook,and the power went out.The wind began to roar through the house,most likely through blown-out windows and the door to our garage.We had three flights of steps to navigate to get to the relative safety of the first floor,because the cupboard down there is underneath a brick staircase.

I didn't know how or if we would make it down the steps.It felt as if there were no floor underneath me as the wind lifted me off my feet.I tried to move forward,but this intense pressure held me in place.

As we reached the last flight of steps,our front door blew out.Pieces of glass that looked like crushed ice flew everywhere.Suddenly,a three-foot-long tree branch crashed into the door frame.It flew over our heads,missing us by inches.Had we been one step up,it would have hit us.

By the time I reached the cupboard,the tornado had been over us for about a minute.Jimmy pushed me down to the cupboard floor,but he couldn't get inside himself because of the wind.I held Jimmy's arm and tried to bring Jimmy with it.My knees were full of glass,but at that moment,I felt no pain.If I had let go,Jimmy would have flown right out the back of the house and into the bay.

All of a sudden,Jimmy lifted off his feet like people in tornadoes do in the movies.I thought he was gone.And then everything stopped.He landed on his feet.In those first quiet moments,I couldn't believe it was over,Jimmy said he'd go outside to check."No,"I said."Don't leave me.Don't leave me."

Our neighbor says the storm lasted four minutes.In that time,four of the twelve town houses in our unit were completely destroyed.Of the houses left standing,ours suffered the most damage.Amazingly,none of us were severely injured.

1.What does the underlined word coverage mean?

A. power B. description

C. arrival D. delay

2.Which of the following sentences is NOT true about the passage?

A. There was not any symbol of the tornado's coming.

B. A three-foot-long tree branch hit the couple.

C. Both of the couple couldn't get into the cupboard floor.

D. Jimmy didn't fly right out the back of the house.

3.Why didn't the wife feel pain?

A. Because she didn't get any hurt when the storm hit.

B. Because she was too scared to feel pain.

C. Because she devoted all her strength to holding on to her husband.

D. Because she had reached the cupboard and she was safe.

4.The author wrote the passage to .

A. share with us her experience of surviving a tornado

B. warn us of the danger caused by tornados

C. show us how to fight against a tornado

D. tell us how to protect us from dangerous tornados

When I was eight, I wrote my first poem. My mother read and cried, “Buddy, you didn’t really write this beautiful poem!” Shyly, but _________, I said yes. She poured out her_________. “It was nothing short of talent!” “What time will Father be home?” I asked. I could_________wait to show my work to him. I spent quite some time_________for his arrival. I wrote the poem out in my finest flourish（花体字）, drew a fancy border around it and_______I placed it right on my father's plate on the dining table. My father had begun his motion-picture career as a writer. I was sure he would be able to_______my poem.

At almost 7 o'clock my father burst in. He seemed _______. He circled the dining-room table, complaining about his employees. _______ he paused and glared at his plate. "What is this?" He was reaching for my poem. “Ben, Buddy has written his first poem!” my mother began. "And it's beautiful, absolutely amaz…”“If you don't mind, I'd like to decide for myself." Father said. I _______my head as he read that poem. It was only ten lines. But it seemed to take hours. Then I heard him dropping the poem back on the table. Now came the moment of __________ “I think it's terrible," he said. I couldn't look up. My eyes were getting____________.

“Ben, these are the first lines of poetry he's ever written," my mother was saying. "He needs encouragement.”

“I don't know why." My father held his ground. "Isn't there enough __________ poetry in the world already?" I couldn't____________it another second. I ran from the dining room crying. Up in my room I ____________ myself on the bed and cried the worst of the disappointment out of me.

That may have been the end of the story, but not of its ____________for me. I realized how__________ I had been. I had a mother who said, "I think it's wonderful!" and a father who drove me to hear with "I think it's awful." Every one of us needs that mother force, from which all creation flows; and yet the mother force alone is __________. It needs the balance of the force that __________, "Watch. Listen. Review. Improve."

Those__________voices of my childhood ring in my ears through the years, like two opposing winds blowing me. __________ the two poles of confirmation and doubt, both in the name of love, I try to follow my true course.

1.A. proudly B. slowly C. anxiously D. honestly

2.A. praise B. surprise C. criticism D. belief

3.A. seldom B. hardly C. frequently D. instantly

4.A. waiting B. planning C. praying D. preparing

5.A. embarrassedly B. confidently C. nervously D. casually

6.A. read B. revise C. appreciate D. polish

7.A. allergic B. fragile C. tired D. upset

8.A. Excitedly B. Suddenly C. Surprisingly D. Instantly

9.A. shook B. raised C. turned D. lowered

10.A. truth B. struggle C. decision D. discussion

11.A. wet B. wide C. dark D. bright

12.A. terrible B. elegant C. fluent D. inaccurate

13.A. stop B. see C. stand D. control

14.A. seated B. threw C. stuck D. kept

15.A. difficulty B. development C. significance D. challenge

16.A. enthusiastic B. fortunate C. desperate D. ridiculous

17.A. incomplete B. contradictory C. inappropriate D. constructive

18.A. orders B. persuades C. warns D. announces

19.A. conflicting B. warning C. disturbing D. inspiring

20.A. In B. Between C. Among D. For

If you want to keep fit, please refer to the following.

Move More

Make it a daily thing to find ways to move your body. 1. Climb stairs instead of taking the elevator. Walk your dog. Play with your kids. It doesn’t have to be an hour in the gym or a 45-minute dance class. But that’s great when you’re up to it. At the same time, move more.

Quit Smoking

Ever since 1960 when it was announced that smoking was harmful to health, Americans have been reducing their use of tobacco products. Just recently, we’ve seen more and more teens smoking. Could it be the Hollywood influence? 2. Take care! Warn your children against smoking.

While recent studies show a glass of wine or one drink a day can help protect against heart disease, more than that can cause other health problems such as liver and kidney(肝肾)disease and cancer.

Reduce Stress

Easier said than done, stress comes in many ways. 4. Spend 30 minutes a day doing something you like such as walking on the beach or in a park, reading a good book, visiting a friend, listening to relaxing music, and watching a funny movie.

Protect Yourself from Pollution

If you can’t live in a smog-free environment, at least avoid smoke-filled rooms. 5.Exercise indoors in air conditioning when air quality is good.

A. Avoid Excessive（过度的） Drinking

B. Keep a Positive Mental Outlook

C. Think carefully about what you will do.

D. Exercise outside when the smog rating is low.

E. It seems that the stars in every movie smoke cigarettes.

F. There are many things you can do to move your arms and legs.

G. Some techniques given by experts are to think positive thoughts.

One day I was thinking of something new to read.When I asked my sister for1.(suggest),she told me to read A Child Called "It".After reading this book,it2.(natural) became my favorite book.It taught me a lot of necessary things in life many people don't bother to appreciate until they're3.(miss).

This book has inspired me in many ways.It made me realize that I'm so fortunate to have a caring and loving mom.As I read the book,I4.(notice) what the boy wanted was love from his mom,but that was impossible for him to get.5.,his mom would abuse him.This book also taught me to appreciate and be happy6.what I have.I often cry because I'm unable to get new shoes or clothes.The child in the book was hardly surviving with the things7.he had.He hardly had enough clothes over8.(he) body to keep him from freezing and he didn't even have shoes.

Until this day,A Child Called "It"9.(be) still my favorite book.10.(inspire) by this book,I'm sure to become a better person.

The British like DIY(do it yourself). A lot of people always spend their holidays 1.(make) their homes more beautiful. If there is anything 2. needs repairing or decorating around their homes, such as painting walls and putting in a new shower, they will do the jobs 3.(they). They share DIY experience4.their friends. DIY can save money. So, it is not surprising that DIY is very popular.

DIY can be difficult. People often find it not easy5.(build) a piece of furniture because they can’t understand the directions（说明书)6.(good) . What’s more, DIY can also be 7.(danger). For example, anything electrical should be done by a professional (专业的) worker.8.(unlucky), many people don’t care about this warning and put themselves in danger. It is reported that thousands of people9.(hurt) while doing DIY in the UK last year. All in all, DIY can bring us fun and help us save money, 10.it is not always as easy as it is thought to be.

Mr. and Mrs．White had two sons and three daughters．One Sunday，Mrs. White said to her husband，“The children don’t have any lessons today，and you’re free too．There’s a new funfair(游乐场)in the park．Let’s all go there to play. ”

Her husband said，“1 want to finish some work today. ” “Oh, forget it．Go there and make our children happy．That’s the most important work.” Mrs. White said.

So Mr. and Mrs. White took their children to the funfair．Mr. White was forty-five years old, but he enjoyed the funfair more than his children. He hurried from one thing to another，and ate lots of sweets. One of the children said to her mother，“Dad is just like a small child，isn’t he, Mom?” Mrs. White didn’t want to follow her husband around any more at that time and answered，“He is even worse than a small child，Mary，because he might spend more money than a small child.”

1.There were ________ children in the White family.

A. two B. three

C. four D. five

2.One Sunday，Mr．and Mrs. White wanted to go to _______ with their children.

A. school B. work

C. a funfair D. a shop．

3.From the story we know Mrs．White________ when Mary asked her the question.

A. was still excited to play B. was a little angry with Mr. White

C. looked for Mr．White everywhere D. ate a lot of sweets

4.Of all he family members,_________ enjoyed playing there most that Sunday.

A. Mr．White B. Mrs．White

C. Mary D. the boys

试题分类