职称英语《理工A》阅读理解练习题及答案.pdfVIP

职称英语《理工A》阅读理解练习题及答案

2017职称英语《理工A》阅读理解练习题及答案

阅读理解题

partA

SuperconductorCeramic陶瓷)

Anundergroundrevolutionbeginsthiswinter.Withtheflip

(轻击)ofaswitch,30,000homesinonepartofDetroitwillsoon

becomethefirstinthecountrytoreceiveelectricitytransmitted

byice-coldhigh-performancecables.OtherAmericancitiesare

expectedtofollowDetroitsexampleintheyearsahead,which

couldconserveenormousamountsofpower.

ThenewelectricalcablesattheFrisbiepowerstationin

Detroitarerevolutionarybecausetheyaremadeof

superconductors.Asuperconductorisamaterialthattransmits

electricitywithlittleornoresistance.Resistanceisthedegreeto

whichasubstanceresistselectriccurrent.Allcommonelectrical

conductorshaveacertainamountofelectricalresistance.They

convertatleastsomeoftheelectricalenergypassingthrough

themintowasteheat.Superconductorsdont.Noone

understandshowsuperconductivityworks.Itjustdoes.

Makingsuperconductorsisnteasy.Asuperconductor

materialhastobecooledtoanextremelylowtemperatureto

loseitsresistance.Thefirstsuperconductors,mademorethan50

yearsago,hadtobecooledto-263degreesCelsiusbeforethey

losttheirresistance.Newersuperconductingmaterialslosetheir

resistanceat-143degreesCelsius.

ThesuperconductorscableinstalledattheFrisbiestationis

madeofaceramicmaterialthatcontainscopper,oxygen,

bismuth(铋),strontium(锶),andcalcium(钙).Aceramicisahard,

strongcompoundmadefromclayorminerals.The

superconductingceramichasbeenfashionedintoatapethatis

wrappedlengthwisearoundalongtubefilledwithliqui