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1、材料科学与工程专业英语PART1INTRODUCTIONTOMATERIALSSCIENCEANDENGINEERING材料科学与工程概论UNIT1MaterialsScienceandEngineering材料科学与工程Materialsareproperlymoredeep-seatedinourculturethanmostofusrealize.Transportation,housing,clothing,communication,recreationandfoodproduction一一virtuallyevery
2、segmentofoureverydaylivesisinfluencedtoonedegreeoranotherbymaterials.Historically,thedevelopmentandadvancementofsocietieshavebeenintimatelytiedtothemembers'abilitiestoproduceandmanipulatematerialstofilltheirneeds.Infact,earlycivilizationshavebeendesignatedbythelevelo
3、ftheirmaterialsdevelopment(i.e.StoneAge,BronzeAge).Theearliesthumanshasaccesstoonlyaverylimitednumberofmaterials,thosethatoccurnaturallystone,wood,clay,skins,andsoon.Withtimetheydiscoveredtechniquesforproducingmaterialsthathadpropertiessuperiortothoseofthenaturalones
4、:thesenewmaterialsincludedpotteryandvariousmetals.Furthermore,itwasdiscoveredthatthepropertiesofamaterialcouldbealteredbyheattreatmentsandbytheadditionofothersubstances.Atthispoint,materialsutilizationwastotallyaselectionprocess,thatis,decidingfromagiven,ratherlimite
5、dsetofmaterialstheonethatwasbestsuitedforanapplicationbyvirtueofitscharacteristic.Itwasnotuntilrelativelyrecenttimesthatscientistscametounderstandtherelationshipsbetweenthestructuralelementsofmaterialsandtheirproperties.Thisknowledge,acquiredinthepast60yearsorso,hase
6、mpoweredthemtofashion,toalargedegree,thecharacteristicsofmaterials.Thus,tensofthousandsofdifferentmaterialshaveevolvedwithratherspecializedcharacteristicsthatmeettheneedsofourmodernandcomplexsociety.Thedevelopmentofmanytechnologiesthatmakeourexistencesocomfortablehas
7、beenintimatelyassociatedwiththeaccessibilityofsuitablematerials.Advancementintheunderstandingofamaterialtypeisoftentheforerunnertothestepwiseprogressionofatechnology.Forexample,automobileswouldnothavebeenpossiblewithouttheavailabilityofinexpensivesteelorsomeothercomp
8、arablesubstitutes.Inourcontemporaryera,sophisticatedelectronicdevicesrelyoncomponentsthataremadefromwhatarecalledsemiconductingmate