济南大学专业英语考试.docx

济南大学专业英语考试.docx

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济南大学专业英语考试

1.Whatarecomposites?

Characteristics,types什么是复合材料？

特点、类型（p98）

Composites:

compositesarehybrid混合的creationsmadeoftwoormorematerialsthatmaintaintheiridentities（身份）whencombined.Theyarecombinationsofmaterialsassembled（组合的）togethertoobtainpropertiessuperiortothoseoftheirsingleconstituentcharacteristics.Theyareexpensivecompetewithmetalandpolymers（高分子）becausethemanufacturing（制造）ofcompositesinvolvesmanysteps.It’sdifficulttorecycle.

Characteristics:

（1）Thepropertiesofoneconstituent（成分）enhancethedeficient（不足）propertiesoftheother.

（2）Usually,agivenpropertyofacompositeliesbetweenthevaluesforeachconstituent.

（3）Sometimes,thepropertyofacompositeisclearlysuperiortothoseofeitheroftheconstituents.

（4）Becausemanufacturingofcompositesinvolvesmanystepsandislabourintensive（劳动力密集型产业）,compositesmaybetooexpensivetocompetewithmetalsandpolymers,

（5）Compositesareusuallydifficulttorecycle.

Types（P96）:

Compositesareclassifiedaccordingtothenatureoftheirmatrix:

metal,ceramic（陶瓷）,polymercomposite,oftendesignated（指定的）MMCs金属基复合材料,CMCs陶瓷基复合材料,PMCs聚合物基复合材料

2.classificationofmaterials材料的分类？

Materials：

Natural、InorganicNon-MetallicMaterials,Ceramics、OrganicMaterials（Polymers,blends混纺）、Metals（Alloys）、Semiconductors、Composites、Biomaterials（生物材料）

Accordingtotheirproperties,materialscanbebroadlyclassifiedintothefollowinggroups:

Structuralmaterials、Functionalmaterials、Smartmaterials（智能材料）

Scale（数值范围）ofMaterials：

1.Nanoscale,sizesofabout1to100nanometers；

2.Microscale,relevantformicro-devicesandmicrosystemshavingsizesoftypically1to1000micrometers（微米）；

3.Macroscalematerials（宏观材料）havethedimensionsofallcustomaryproducts,devicesandplants,rangingfromthemillimeter（毫米）tothekilometerscale。

3.Physicalproperties（names）物理性质（名称）

Themechanicalproperties（机械性质）ofmaterial:

bendtest（弯曲试验）:

ductility（延展性）,elasticity（弹性）,brittleness（脆性）.Tensiletest（抗拉试验）:

yieldstrength（屈服强度）,tensilestrength（抗张强度）.Hardnesstest（硬度试验）:

hardness.Impacttest（冲击试验）:

toughness（韧性）undershock（冲击）.Fatiguetest疲劳试验:

fatiguebehavior.Stiffness（硬度）;Creeptest蠕变试验:

creep.

Thermalproperties:

thermalconductivity（热导率）,specificheatcapacity（比热容）;Opticalproperties（光学性质）:

reflection（反射）refraction（折射）dispersion（散射）;

Electricalproperties（电学性质）：

conductivity（导电性）,resistivity（电阻率）,particle-wavedualityoflight;Magneticproperties:

perneabolity,susceptibility（敏感性）,magneticinduction,

4.Howtogetthestress-straincurve?

Whataretheparameterscanwegetfromthiscurve?

如何得到应力-应变曲线？

我们从这个曲线得到什么参数？

Theresultofatensiletestiscommonlydisplayedinastress–straindiagram.

Y:

stress,tensilestress.X:

strain.Undertensilestress,therodbecomeslongerinthedirectionoftheappliedforce（andeventuallynarrowerperpendiculartothataxis）,thechangeinlongitudinaldimensioninresponsetostressiscalledstrainε:

Parameters参数：

（1）yieldstrength屈服强度σy

（2）modulusofelasticity弹性模量E（3）tensilestrength抗张强度σt（4）necking（5）breakingStrength力量σb（6）Stress,压力σ;（7）strain,张力ε

5.whataretoughnessundershock,fatiguebehavior,creep?

什么是冲击韧性、疲劳行为、蠕变？

（p22）

Toughnessundershock:

Whensubjectedtoasuddenblow,somematerialsbreakatalowerstressthanthatmeasuredusingatensilemachine.Theimpacttesterinvestigatesthetoughnessofmaterialsbystrikingthematthecenterwhilefixingbothends.Toughnessisdefinedastheenergy（nottheforce）requiredtobreakamaterial.

Fatiguebehavior:

Materials,evenwhenstressedbelowtheyieldstrength,stillmayeventuallybreakifalargenumberoftensionandcompressioncyclesareapplied.Thefatiguetestmeasuresthenumberofbendingcyclesthatneedtobeappliedforaspecificloaduntilfailureoccurs.

Creep:

Thecreeptestmeasuresthecontinuousandprogressiveplasticdeformationofmaterialsathightemperatureswhileaconstantstressoraconstantloadbelowtheroomtemperatureyieldstrengthisapplied.

6.Whatarephonons?

Heatcapacity?

什么是声子？

热容？

（p272）

Theheatcapacity,C:

istheamountofheat,dQ,thatneedstobetransferredtoasubstanceinordertoraiseitstemperaturebyacertaintemperatureinterval.TheunitfortheheatcapacityisJ/K.

Photons：

Duringtheabsorptionoflightbyintrabandtransitions,anadditionalmechanismmaytakeplace.Itinvolveslatticevibrationquantacalledphonons.Theyarequantaoftheionicdisplacementfieldwhichrepresentclassicalsound;thewordphononconveystheparticlenatureofanoscillator（振子）.

7.illustrateslightinteractionwithmatter说明（举例说明）光与物质的相互作用。

Absorptionoflight；Emissionoflight；refractionoflight；dispersionoflight；reflectionoflight；transmissionoflight；diffractionoflight；interferenceoflight.

8.luminescenceandmechanism?

发光和机制（p259）Whatarelasers?

什么是激光？

Howtheyareobtained?

如何获得激光（P261）？

Luminescence:

Theemissionoflightduetoreversionofelectronsfromahigherenergystateiscalledluminescence.

Mechanism:

Anelectron,onceexcited,musteventuallyrevertbackintoalower,emptyenergystate.Thisoccurs,asarule,spontaneouslywithinafractionofasecondandisaccompaniedbytheemissionofaphotonand/orthedissipationofheat---phonons.

Laser:

lightamplificationbystimulatedemissionofradiation.

Stimulatedemissionoflightoccurswhenelectronsareforcedbyincidentradiationtoaddmorephotonstoanincidentbeam.

9.Thermoelectricityandpiezoelectricity?

Examplesandapplications?

热电和压电？

举例和应用（p220/p212）

Piezoelectricity:

Thepressureisappliedtoaferroelectricmaterial,achangeinthejust-mentionedpolarizationmayoccurwhichresultsinasmallvoltageacrossthesample.Theslightchangeindimensionscausesavariationinbondlengthsbetweencationsandanions.Thiseffectiscalledpiezoelectricity.

Examples:

Quartz（石英）,BaTiO3,inZnO,inPbZrTiO6;

applications:

Piezoelectricityisutilizedindevicesthataredesignedtoconvertmechanicalstrainintoelectricity.Thosedevicesarecalledtransducers.Applicationsincludestraingages,microphones,sonardetectors,andphonographpickups,tomentionafew.

Thermoelectricity:

Assumetwodifferenttypesofmaterials（e.g.,acopperandanironwire）whichareconnectedattheirendstoformaloop.Oneofthejunctionsisbroughttoahighertemperaturethantheother.Thenapotentialdifference,△V,betweenthesetwothermocouplesisobservedwhichisessentiallyproportionaltothetemperaturedifference,△T,where:

△V/△T=Siscalledthethermoelectricpower.

Examplesandapplications:

Thermocouplesmadeofmetalwiresareutilizedasrigid,inexpensive,andfastprobesformeasuringtemperaturesevenatotherwisenoteasilyaccessibleplaces.Thermoelectricpowergenerators（utilizingtheabove-mentionedsemiconductors）areusedparticularlyinremotelocationsoftheearth（Siberia,Alaska,etc.）.

10.Influenceoftemperatureandimpurityonresistenceofmetals?

Explanations温度和杂质对金属电阻的影响？

（P187）解释.

Theresistivityofmetalsessentiallyincreaseslinearlywithincreasingtemperatureaccordingtotheempiricalequation（经验方程）:

ρ2=ρ1[1+α（T2-T1）]whereαisthelineartemperaturecoefficientofresistivity,andT1andT2aretwodifferenttemperatures.

Explanation:

Athighertemperatures,thelatticeatomsincreasinglyoscillateabouttheirequilibriumpositionsduetothesupplyofthermalenergy,thusenhancingtheprobabilityforcollisionsbythedriftingelectrons.Asaconsequence,theresistanceriseswithhighertemperature.Atnear-zerotemperature,theelectricalresistancedosenotcompletelyvanishandtheresidualresistivityisessentiallytemperature-independent.

11.bandstructureofsemiconductors半导体的能带结构？

Intrinsicsemiconductorhasthreeelectronbandswhicharevalenceband,conductionbandandforbiddenband.Thereiscompletelyfilledwithvalenceelectronsinvalencebandandconductionbandcontainsnoelectrons.Theforbiddenbandisnotallowedtheelectronsresideinthegap.Sincethefilledvalencebandpossessesnoallowedemptyenergystatesinwhichtheelectronscanbethermallyexcited（andthenacceleratedinanelectricfield）,andsincetheconductionbandcontainsnoelectronsatall,silicon,at0K,isaninsulator.

Twoelectronbands,thelowerofwhich,at0K,iscompletelyfilledwithvalenceelectronscalledthevalenceband.Itisseparatedbyasmallgapfromtheconductionband,which,at0K,containsnoelectrons.Further,quantummechanicsstipulatesthatelectronsessentiallyarenotallowedtoresideinthegapbetweenthesebands（calledtheforbiddenband）.Sincethefilledvalencebandpossessesnoallowedemptyenergystatesinwhichtheelectronscanbethermallyexcited（andthenacceleratedinanelectricfield）,andsincetheconductionbandcontainsnoelectronsatall,silicon,at0K,isaninsulator.

12.types,application,machenismsofmagneticmaterials（names,differences）磁性材料的类型、应用和机理。

（名字、差异）

paramagnetics,diamagnetics,ferromagnetics,ferriamgnetics,andantiferromagnetics.

AqualitativeaswellasaquantitativedistinctionbetweenthesetypescanbeachievedinarelativelysimplewaybyutilizingamethodproposedbyFaraday.

Magneticmaterialtobeinvestigatedissuspendedfromoneofthearmsofasensitivebalanceandisallowedtoreachintoaninhomogeneousmagneticfield.Diamagneticmaterialsareexpelledfromthisfield,wherepara-,ferro-,antiferro-,andferrimagneticsareattractedindifferentdegrees.

FIGURE12.2.Schematicrepresentationofmagneticfieldlinesinandarounddifferenttypesofmaterials.（a）Para-orferromagnetics铁磁体.Themagneticinduction（B）磁感应强度insidethematerialconsistsofthefree-spacecomponent（0H）plusacontributionbythem