中日韩va无码中文字幕_亚洲va中文字幕无码久_又粗又大又黄又刺激的免费视频_成年人国产免费网站

當前位置:

職稱英語考試試題每日一練—《衛(wèi)生類》1.17

發(fā)表時間:2014/1/17 16:43:18 來源:互聯網 點擊關注微信:關注中大網校微信
關注公眾號
職稱英語考試試題每日一練——《衛(wèi)生類
二級建造師考試試題

Sugar Power for Cell Phones

Using enzymes commonly found in living cells,a new type of fuel cell produces small amounts of electricity from sugar.If the technology is able to succeed in mass production,you may some day share your sweet drinks with your cell phone.

In fuel cells,chemical reactions generate electrical currents.The process usually relies on precious metals,such as platinum.In living cells,enzymes perform a similar job,breaking down sugars to obtain electrons and produce energy.

When researchers previously used enzymes in fuel cells,they had trouble keeping them active,says Shelley D.Minteer of St Louis University1.Whereas biological cells continually produce fresh enzymes,there’s no mechanism in fuel cells to replace enzymes as they quickly degrade.

Minteer and Tamara Klotzbach,also of St Louis University,have now developed polymers that wrap around an enzyme and preserve it in a microscopic pocket.“We tailor these pockets to provide the ideal microenvironment” for the enzyme,Minteer says.The polymers keep the enzyme active for months instead of days.

In the new fuel Cell,tiny polymer bags of enzyme are embedded in a membrane that coats one of the electrodes.When glucose from a sugary liquid gets into a pocket,the enzyme oxidizes it,releasing electrons and protons.The electrons cross the membrane and enter a wire through which they travel to the other electrode,where they react with.oxygen in the atmosphere to produce water.The flow of electrons through the wire constitutes an electrical current that can generate power.

So far,the new fuel cells don’t produce much power,but the fact that they work at all is exciting,says Paul Kenis,a chemical engineer at the University of Illinois2 at Urhana-Champaign3.“Just getting it to work.” Kenis says,“is a major accomplishment.”

Sugar-eating fuel cells could be an efficient way to make electricity.Sugar is easy to find. And the new fuel cells that run on it are biodegradable,so the technology wouldn’t hurt the environment.The scientists are now trying to use different enzymes that will get more power from sugar.They predict that popular products may be using the new technology in as little as 3 years.

詞匯:

enzyme/5enzaIm/n.酶 electrode/I5lektrEJd/n.電極platinum/5plAtinEm/n.鉑,白金 membrane/5membrein/n.膜,薄膜

electron/I5lektrRn/n.電子 oxidize/5Cksi7daiz/v.氧化degrade/di5reid/v.降解 glucose/5lu:kEus/n.葡萄糖

polymer/5pClimE/n.聚合物 biodegradable/7baiEudi5reidEbl/adj.能進行生物降解的

microenvironment n.微環(huán)境 embed/im5bed/v.埋置,插入

proton/5prEutCn/n.質子

試題

1. According to the first paragraph,when can we share our sweet drinks with our cell phones?

A When enzymes can be commonly found in living ceils.

B When the technology of producing a new type of fuel cell appears.

C When the technology of a new type of fuel cell is suitable for mass production.

D When the technology of mass producing cell phones appears.

2. What trouble did Minteer and Klotzhach have in their research?

A They had trouble keeping enzymes in fuel cells active.

B They had trouble keeping biological cells active.

C They had trouble producing fresh enzymes.

D They had trouble finding mechanism for producing enzymes.

3. According to Paragraph 5,electrons are released

A when bags of enzyme are embedded in the new fuel cell.

B when glucose from a sugary liquid goes through the enzyme.

C when the enzyme oxidizes the glucose from a sugary liquid that goes through

a pocket.

D when the enzyme oxidizes the sugary liquid that goes through a pocket.

4. What is exciting about the new fuel cells?

A Their limitless power generation capacity is amazing.

B Their limited power generation capacity is a good beginning.

C Their limited power generation capacity is the result of great efforts.

D Their limitless power generation capacity is a major accomplishment,

5. According to the last paragraph,what is NOT true of the new fuel cells?

A The new fuel cells run on sugar that is easy to find.

B The new fuel cells are environment friendly.

C The new fuel cells are biologically degradable,

D It will take some time before the new fuel cells can be used in popular products.

答案與題解:

1. C A和D明顯不是正確答案。B不是正確選擇,因為只有當這種新的燃料電池被大規(guī)模生產時,才有可能實現用甜飲料給手機提供電能。

2. A 文章第三段的第一句是問題的答案。

3. C 該段第二句“When glucose from a sugary liquid penetrates a pocket,the enzyme oxidizes it,releasing electrons and proton”中的it指代glucose,而不是a sugary liquid,因 此C是正確選擇。

4. B 第六段的大意是,盡管這種新型燃料電池還不能產牛很多電能,但是,它能夠產生電能的事實就已經是很大的成就了。因而激動人心。所以只有B是正確答案。

5. D 文章的最后一段指出了這種新型燃料電池的優(yōu)點,即A、B、C所述內容。最后一句說,科學家預計,在不到三年的時間里這種新技術便可在大眾的流行產品中使用。所以D是正確選擇。

二級建造師考試答疑

針對2014年職稱英語考試備考,總有另考生束手無策的疑難問題。例如,對于想參加2014年職稱英語考試的新考生來說,2014年職稱英語報名條件、職稱英語考試科目等考試信息,你是否想詳細咨詢一下?如果你有意向參加中大網校職稱英語考試培訓職稱英語輔導優(yōu)惠方案你是否想了解一下?在聽課過程中,如果你對某一個知識點有疑問等,諸如此類的問題和疑惑,你都可以通過職稱英語考試你問我答平臺,發(fā)起你的疑問,屆時,中大網校職稱英語培訓顧問及資深命題專家將在第一時間解答你的疑問。中大網校考試知道,總有人知道你問題的答案,詳情請查看>>

2014年全國職稱英語考試報名時間信息匯總
2014年1月份職稱英語考試試題每日一練匯總
2014年職稱英語考試教材與輔導用書
2014年職稱英語考試最新招生方案

(責任編輯:wrr)

2頁,當前第1頁  第一頁  前一頁  下一頁
最近更新 考試動態(tài) 更多>