首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
医学
Dry-cleaning machines that use liquid carbon dioxide as a solvent will go on sale in the US next year—thanks to chemists in Nort
Dry-cleaning machines that use liquid carbon dioxide as a solvent will go on sale in the US next year—thanks to chemists in Nort
admin
2013-10-31
65
问题
Dry-cleaning machines that use liquid carbon dioxide as a solvent will go on sale in the US next year—thanks to chemists in North Carolina who have developed CO
2
-soluble detergents.
Dry-cleaners will lose their characteristic smell, and the new process will cut the amount of toxic waste produced in cleaning clothes.
Joseph DeSimone, a chemist at the University of North Carolina, Chapel Hill, says liquid CO
2
is an ideal solvent because after cleaning, the CO
2
can be evaporated off, collected, liquefied and reused.
The problem in developing the process, says DeSimone, has been that CO
2
by itself is not a good solvent. However, he points out that not much dissolves in water without the help of detergents, yet water is the most common solvent. What CO
2
needed, he thought, was the right detergent.
Detergent molecules such as those in washing-up liquid have two chemically distinct ends; one has a liking for water, the other sticks to dirt. Normal detergents do not dissolve in liquid CO
2
, so DeSimone created three CO
2
-soluble detergents. One end of the detergents has a fluorocarbon group, which makes them soluble in CO
2
. The other end is soluble in water, oil or silicone, depending on the type of dirt being removed. The person doing the dry-cleaning has to decide which of the detergents is best for the job.
DeSimone’s company, MiCell, will start selling liquid CO
2
dry-Cleaning machines next year. They operate at room temperature at a pressure "about ten times the pressure of a bicycle tyro" , according to a spokesman for MiCell.
Most dry-cleaners currently use chlorinated hydrocarbons such as perchloroethylene. But the US Environmental Protection Agency(EPA)is clamping down on the toxic waste emission this produces. After cleaning with the new machines, the liquid CO
2
is evaporated and collected for reuse, leaving a residue of detergent and dirt.
Brad Lienhart, president of MiCell, says that cutting waste and pollution is the company’ s strongest selling point. " Dry-cleaner owners are saying ’ get this burden off my back’ ," he says. He hopes to sell a hundred machines, in the first year of business. About 15000 conventional drycleaning machines are sold around the world every year. Buster Bell, who owns Bell Laundry and Dry Cleaning in South Carolina, says the MiCell-technology looks competitive, and he likes the reduced environmental impact. "You really don’t know what is coming from the EPA," he says.
The right detergent for CO
2
______.
选项
A、makes dry cleaning easy
B、must be chemically soluble.
C、is chemically of two purposes
D、means a right person for dry-cleaning
答案
B
解析
根据文章第四段,二氧化碳本身并不是溶剂,如没有适当的洗洁剂,二氧化碳很少溶于水,而水是最常用的溶剂,所以适当的洗洁剂应该是可溶解的。
转载请注明原文地址:https://kaotiyun.com/show/iGU3777K
本试题收录于:
医学博士外语题库考研分类
0
医学博士外语
考研
相关试题推荐
Cultureshockmightbecalledanoccupationaldiseaseofpeoplewhohavebeensuddenlytransplantedabroad.Likemostailments,
A、It’sraining.B、Shedoesn’tlikeplayingtennis.C、Shedoesn’twanttogetsunburned.D、It’snotaholiday.C女士讲到自己不会去网球场,因为那
Thepopularideathatclassicalmusiccanimproveyourmathsisfallingfromfavor.Newexperimentshavefailedtosupportthew
Seanalivedintheinpatienthospiceunitformorethanamonth,farlongerthananyonewouldhavepredicted,sustainedonlyon
A、Shedidpoorlyonphysics.B、ShegotaBinphysics.C、Shedidn’twantto.D、Shewasanaveragestudent.A女士讲到自己的物理只拿到了“D”,因而
Whydopeoplealwayswanttogetupanddancewhentheyhearmusic?Theusualexplanationisthatthereissomethingembeddedin
Thetutortellstheundergraduatesthatonecanacquire______inaforeignlanguagethroughmorepractice.
A、ShewillapplytoDukeUniversity.B、ShewillprobablyattendtheUniversityofTexas.C、Shemadeuphermindtogiveupschoo
A、Writinganarticle.B、Studyingforaphysicstest.C、Shoppingforshoes.D、Readingamagazine.B女士说如果不是关于物理和期末考试她就不关心,言外之意是物理考
Theprevalenceofhighlyintelligentdeviceshaseliminatedthehandicapsassociatedwithmostdisabilities.
随机试题
关于设备监理单位与承包商之间的组织协调,下列说法错误的是()。
甘草皂苷元是
屈光调节性内斜视先天性内斜视
林某与甲房地产经纪公司签订房屋委托购买合同。合同约定,甲公司为林某购买某小区一套住房,房价款为24万元。购房定金1万元,林某一次性支付购房款,其首付款不低于房价款的30%,余款在该房房屋产权转移前3日内补齐。甲公司为林某办理房屋过户手续后,林某支付8万元,
采用变水头恒速过滤的滤池有()。
拔掉那颗蛀牙①她恨全家人。②她在家中的地位很尴尬。姐姐比她漂亮。因为想要儿子,父母坚持要生,结果生下她,还是女儿。后来,又生了弟弟,弟弟显然是最得宠爱的。父母的理念就是,闺女是要嫁出去的,对这个家无关紧要,能养着就不错了!③姐
1/4
ScienceandTruth"FINAGLE"isnotawordthatmostpeopleassociatewithscience.Onereasonisthattheimageofthescient
TheAmericanFamilyIntheAmericanfamilythehusbandandwifeusuallyshareimportantdecisionmaking.Whenthechildrenareo
Theageofgildedyouthisover.Today’sunder-thirtiesarethefirstgenerationforacenturywhocanexpectalowerlivingsta
最新回复
(
0
)