新材料英语 课件 Unit 5 Beyond wares

新材料英语CollegeEnglishfor

NewAgriculturalSciences5UnitBeyondwares新材料英语EnglishforAdvancedMaterialsScienceAfterstudyingthisunit,youwillbeableto:describetheevolutionofceramics,theirkeyproperties,andinnovativeapplications;explainhowakeybreakthroughinbiomimeticcoolingceramicshelpsaddresscoolingchallenges;employtheproblem-solutionpatterninyouracademicwriting;Learning

objectives新材料英语EnglishforAdvancedMaterialsSciencedeliverapopularsciencelectureontheevolutionofceramicsandChinesemodernceramicinnovationsataninternationalevent.Learning

objectives新材料英语EnglishforAdvancedMaterialsScienceCONTENTSTellingChina’sstoriesUnlockingthetopicViewingthroughthelensExploringthefrontier新材料英语EnglishforAdvancedMaterialsScienceSettingthesceneCeramics,oneofhumanity’searliesttechnologicaltriumphs,haveevolvedfromancientartifactsintohigh-techmaterialsthatenableasustainablefuture.Inthisunit,youwillexploretheevolutionofceramicsfromancientfoodvesselstomodernfunctionalmaterials,withafocusonagroundbreakingChineseinnovation:biomimeticcoolingceramicsinspiredbynature.Youwillexaminehowscientistsemployinnovativeceramicmaterialstoaddressglobalchallengessuchasenergyconsumptionandclimatechange.新材料英语EnglishforAdvancedMaterialsScienceSettingthesceneFinally,youwilldeliverapopularsciencelectureontheevolutionofceramicsandarecentChineseinnovationinceramictechnologytoaninternationalaudience.新材料英语EnglishforAdvancedMaterialsScienceScanthecodeandcompletethe

technicalvocabularyexerciseonUcampus.suspensionn.悬浮液dissipatev.（使）消散；消失rareearthn.稀土元素biomarkern.生物标志（物）

arthritisn.关节炎transducevt.

转换Wordbank

Howmuchdoyouknowabouttheevolutionofceramics?Watchthevideoclipandcompletetheoutlinewithwhatyouhear.(Withsubtitles)(Withoutsubtitles)Theprimarygoalwastocreate1)_____________tomeetsocietalneeds(e.g.,foodcontainers).Thekeyprocessinvolvedapplying2)_____________torawmaterialslikeclay,sand,andwater.Theseceramicssupportedbasicneedsandhelpedprovidethe3)____________________forearlycivilizations.I.Ancientphase:TheearlyusesofceramicsusefultoolseconomicfoundationTheevolutionofceramics:FromancientcrafttomoderntechnologyheatModernceramicspossesselectrical,optical,and4)_____________propertiesessentialtomoderntechnology.Themagneticpropertiesofceramicscontributetoapplicationslikeseparatingcirculatingtumorcellsand5)_____________arthriticbiomarkers.FerroelectricRAMutilizesceramics’electricalpropertiestostoreinformationnecessarytopowera(n)6)_____________.II.Presentphase:FunctionalceramicsinmoderntechnologymagneticdetectingsmartcardCeramicsarebecoming7)_______________,abletoconvertenergy,storedata,andaidbiomedicine.Transformingthematthe8)_____________scalepromisesevengreaterpotentialinthefuture.III.Futurephase:ExpandingthefrontiersofceramicsmultifunctionalatomicScanthecodeformorecomprehensionexercisesonUcampus.

ScriptsTheevolutionofceramics:FromancientcrafttomoderntechnologyThroughouthistory,humanshavetakenrawmaterialsfromtheearthandturnedthemintousefultools.Andassciencehasadvanced,wenowusethesesametypesofmaterialsinentirelydifferentways.“Fromancienttimesuntilnow,ceramicshaveplayedahugeroleinsociety.Gotoanynaturalhistoryorartmuseum,andyou’llsee.Earlycivilizationsdiscoveredwhenyoutakeclay,sand,andwaterfromtheearthandapplyheat,youcantransformnotjustthematerials,butsocieties,too.”“Ceramicsareoneofthemostancienttechnologiesofhumanhistory,goingbackatleast20,000years,ifnotmore.Andoneofthelargestapplicationsinceramicsistheproductionoftoolsusedforprocessing,storing,andservingfoods.So,makingceramicswasneverreallytheendgameinandofitself.Itisatoolthat’susedforharnessingtheenergypotentialoffoodsthatweretheeconomicfoundationforcivilization.”Butit’stheelectrical,optical,andmagneticpropertiesofceramicsthathavemadethemsoimportanttoourhigh-techworld.“MynameisCarlosRinaldi.I’maprofessorofchemicalengineeringandbiomedicalengineering.Mylabworkswithmagneticnanoparticles,ingeneral,suspensionsofmagneticnanoparticles.Intermsoffunctionalceramics,theideahereisthatthematerialsarefunctionalfromthepointofviewofhavingamagneticpropertythatallowsthemtorespondtoanappliedmagneticfieldinacertainway,eitherbyrotating,translating,ordissipatingenergy.WhatI’mgoingtoillustratehereistheconceptofmagneticbuoyancy.AndtheideahereisthatIhaveaferrofluid.Inthiscase,it’sabout10nanometerparticlesinanoil-basedoilmedium.AndIhavealittlepieceofplastichere,andit’stoodense,soitdoesn’tfloat.Itsinksallthewaytothebottom.AndI’mgoingtousearareearthpermanentmagnettogenerateamagneticfield.Andwhat’sgoingtohappenisthatthemagnetwillattracttheferrofluidtowardit,andindoingso,it’lldisplacetheplasticandthereforemakeitfloat.Andso,asIapproachit,you’llseethattheplasticpiecefloats,andtheactualpositionoftheplasticpiecedependsontherelativepositionsoftheferrofluidandthemagnet.So,averysimpleandveryexciting,Ithink,exampleofhowthisprincipleofmagneticbuoyancycanbeusedinbiomedicineisinseparatingcirculatingtumorcells.So,theideahereisthatwithverysmallconcentrations,Imean,reallysurprisinglylowconcentrationsofmagneticnanoparticlesintheliquid,youcangenerateamicrofluidicdevice.Youhaveastreamofourcellscomingin,andyouhaveanoutlet.Andthen,youuseamagnettopush.Becauseofbuoyancy,themagneticbuoyancyeffectpusheslargercellstocomeoutofanotherexitinthetop.Andso,thistakesadvantageofthemagneticbuoyancyeffectthatI’veillustrated,andalsoofthedifferencesinthesizeofcirculatingtumorcellsversusnon-cancercellsthatareinthebloodstream.So,anotherapplicationthatwe’redevelopingisusingmagneticnanoparticlesormagneticmicroparticlesforbiomarkerscavengingasawayofdetectingearly-stagebiomarkersforarthritis.Whatwe’retryingtodevelopisanassay,ifyouwill,awayofdetectingandmonitoringprogressionofthediseasebymonitoring,youknow,expressionsofbiomarkersthatareassociatedwiththedisease.”“So,atthebeginningofthevideo,yousawNinausehersmartcardinanATM.Nowthequestionthatyouhavetoaskyourselfis,where’stheceramics’implicationinthosethings,right?Anditturnsoutthatasmartcarduseswhat’scalledferroelectricRAMsometimes.Ferroelectricsisaceramicthathassomeunusualpropertyinthatyoucanstoreapolarizationlikeaoneorazerowithanelectricfield.AndthatmeansIcanstoreintheceramictheinformationnecessarytomakethatsmartcardwork,soitcantellyouwhatyourbalanceiswhenyoulogintothecomputer.We’vegonefromancientceramicsthatwerejustbasicallycoffeecupsandbathtubs,tomodernceramicswhichhavetheabilitytobemultifunctional,sotheycanactuallytransduceenergyfromoneformtoanother.Theycanbeferroelectrics,sotheyhavetheabilitytostoreinformationlikeinyoursmartcard.Theycanbethermoelectrics,sotheycanconvertwasteheatintoelectricityandharnessthatinyourcar.Theycanbemagneticoxideparticlesthatcanbeusedforbiologicalapplications,suchasseparatingcancercellsordetectingarthriticbiomarkersinyourbloodstream.So,theopportunityforfutureceramicsisenormous,andit’sjustbeginningtobetapped.”So,ceramicshavechangedalotoverhistory,butnowtransformingthemattheatomicscalehasunleashedrevolutionarynewpotential.Whatdoyouseeastheirabilitytotransformlivesandsocietyinthefuture?Workingroupsanddiscussthequestions.Whilethevideocliphighlightsthreekeypropertiesofceramicsinmoderntechnology–electrical,magnetic,andoptical,itdoesnotdiscusstheopticalpropertiesindetail.Whatcanyoutellusabouttheopticalcharacteristicsofceramics?Ifyouweretodevelopanewfunctionalceramicproduct,whichpropertieswouldyoufocusonandwhatwouldmotivateyourchoices?Thevideodoesn’tcoveropticalproperties,butadvancedceramicscanhavesomeimportantopticalcharacteristics.Transparency:Speciallyprocessedadvancedceramicscanachievehighopticaltransmissionacrossthevisibleandinfraredspectrum,makingthemusefulforlasers,sensors,andprotectivewindows.ReferenceanswersLightcontrol:Dependingontheirmicrostructure,certainadvancedceramicscanscatter,reflect,orguidelightforapplicationslikewaveguidesorlenses.Luminescence:Someadvancedceramicsconvertabsorbedenergy(e.g.,lightorradiation)intovisiblelightatdifferentwavelengths,enablingapplicationsindisplaysandmedicalimaging.FocusonelectricalpropertiesIwouldfocusondevelopingceramicswithenhancedelectricalproperties,specificallyforenergystorageapplications.Mymotivationstemsfromthegrowingglobaldemandforefficient,compactenergystoragesolutions.Bydesigningceramicswithsuperiordielectricpropertiesorsupercapacitivebehavior,wecoulddevelopnext-generationcapacitorsandbatteriesthatchargefaster,lastlonger,andperformmorereliablyunderextremeconditions.ReferenceanswersSuchadvancementswouldhaveabroadimpact,frompoweringelectricvehiclestosupportingrenewableenergystorage,helpingacceleratethetransitiontowardafuturewithmoresustainableenergy.FocusonmagneticpropertiesMychoicewouldbetodevelopceramicsbasedontheirmagneticproperties,aimingtoadvancetargeteddrugdeliverysystems.Iammotivatedbythepotentialtorevolutionizehowwetreatdiseaseslikecancer.Bydesigningmagneticceramicnanoparticlesthatcanbeguidedthroughthebodyusingexternalmagneticfields,wecoulddeliverdrugsdirectlytotumorsiteswithpinpointaccuracy.Thisapproachwouldmaximizetreatmenteffectivenesswhilegreatlyreducingtheharmfulsideeffectsassociatedwithconventionalchemotherapy,ultimatelyimprovingpatientoutcomesandqualityoflife.FocusonopticalpropertiesIwouldconcentrateonoptimizingtheopticalpropertiesofceramics,particularlyforsolid-statelightinganddisplaytechnologies.Mymotivationliesinthemarket’sgrowingpursuitofhigherenergyefficiencyandimprovedvisualperformance.Byengineeringtransparentorluminescentceramicsthatcancontrollightmoreeffectivelythancurrentmaterials,wecoulddevelopbrighter,moredurable,andmoreenergy-efficientLEDs,lasersources,anddisplayscreens.Thisadvancementwouldnotonlyreduceglobalenergyconsumptionbutalsoenablenewapplicationsinadvancedcommunications,medicalimaging,andultra-highdefinitiondisplays.1Asglobalenergydemandsrise,particularlyforcoolinginwarmerclimates,theneedforsustainablealternativestoconventionalairconditioninghasneverbeenmoreurgent.Onepromisingsolutioncomesfromanunexpectedsource:passiveradiativecooling,anaturalprocessthatallowssurfacestocoolbyradiatingheatintospacewithoutconsumingenergy.BiomimeticceramicsforpassivedaytimeradiativecoolingThisoccursconstantlyonfrostymorningswhendewformsonleaves,oronclearnightswhenobjectsundertheopenskybecomecolderthanthesurroundingair.Theseexamplesillustratehowtheearthcoolsbyemittinginfraredradiationthroughtheatmosphereintospace,especiallywithinaspecificrangeofwavelengthsbetween8and13micrometers,knownastheatmosphericwindow.2

Whiletheconceptofradiativecoolinghasexistedfordecades,applyingitpractically–especiallyduringthedaytime–hasposedmajorchallenges.Theeffectivenessofanypassiveradiativecoolingmaterialdependscriticallyontwokeyopticalproperties:highsolarreflectivitytominimizeheatgainfromsunlight,andhighthermalemissivitywithintheatmosphericwindowtomaximizeheatlosstospace.Inthepastfewdecades,researchershavestruggledtodevelopmaterialsthatexcelinbothpropertiessimultaneously.Traditionalapproachesoftenusedmetallic,silver-basedreflectivelayers,whichonlyreflectedabout90%ofincomingsolarradiation.Thisprovedinsufficientduringdaylighthourswhenthesun’sintenseradiationoverwhelmedtheircoolingcapability.Thislimitationrestrictedmostconventionalradiativecoolerstonighttimeuseonly,despitethefactthatpeakcoolingdemandoccursduringthedaytime.3Itwasthischallengethatinspiredresearcherstolookbeyondconventionaldesignsandturntonatureforsolutions.TheremarkablywhitescalesoftheCyphochilusbeetle,whichachievetheirintensewhitenessthroughsophisticatedporousnanostructuresratherthanpigments,providedthebiologicalblueprintforabreakthrough.Byemulatingthisnaturaldesign,scientistsdevelopedanovelcoolingceramicmaterialthatfundamentallyrethinkshowmaterialscanmanagesolarradiationandthermalemission.

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ThegroundbreakingdevelopmentofthehierarchicallystructuredcoolingceramicwasledbyProf.TsoChiYan(correspondingauthor)fromtheSchoolofEnergyandEnvironmentattheCityUniversityofHongKong,withProf.LinKaixin

asthefirstauthor.Theircollaborativeworkhassuccessfullycreatedaceramicmaterialwithexceptionalopticalproperties,criticaltohigh-performancepassivedaytimeradiativecooling.5

Theextraordinaryopticalperformanceofthecoolingceramicstemsfromasophisticatedcombinationofmaterialpropertiesandmulti-scalestructuralengineering,achievingwhatisconsideredanear-idealresponsefordaytimepassiveradiativecooling.Itscorematerial,α-alumina,isselectedbasedonitsintrinsicelectromagneticcharacteristics.Withawidebandgapof7.0eV–wellabovetheupperboundaryforphotonenergyinthesolarspectrum(around4.13eVforultravioletradiation)–thematerialexhibitsanextremelylowextinctioncoefficientacrosstheentiresolarspectrum.Thisfundamentalpropertyensuresminimalabsorptionofsunlight,providingtheessentialfoundationforhighreflectivity.

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However,achievingnear-perfectsolarreflectionrequiresmorethanjustanon-absorbingmaterial;itdemandsefficientscatteringacrossallsolarwavelengths.Thisisaccomplishedthroughahierarchicallyporousstructureengineeredtomimicthelight-scatteringmechanismofCyphochilusbeetlescales.Thecoolingceramiccontainsporesizesrangingfromnanometerstoseveralmicrometers.Thismulti-scaleporosityiscrucialforinducingstrongMiescatteringoverabroadbandwidth.Smallerpores,withdiametersaround200–300nanometers,efficientlyscattervisibleandultravioletlightduetotheirsizebeingontheorderofthesewavelengths.Meanwhile,largerporesinthemicrometerrangescatternear-infraredradiation,whichconstitutesasignificantportionofsolarenergy.7

Theresultisaremarkablesolarreflectivity(Rsolar)of99.6%,meaningthematerialreflectsnearlyallincidentsunlightfromtheultraviolet(250nm)tothenear-infrared(2,500nm).Thisperformanceestablishesitamongthewhitestandmosthighlyreflectiveceramicmaterialsknowntodate,minimizingsolarheatgaintoanunprecedenteddegreeandallowingthesurfacetoremaincoolerthanambientairevenunderintensesolarirradiation.8

Simultaneously,thecoolingceramicmustefficientlyradiateaccumulatedheatoutwardthroughtheearth’satmosphericwindow(8–13μm).Thisisenabledbyanotherintrinsicpropertyofalumina:thevibrationalmodesofitsatomicbonds.TheAl–Obondsresonateatwavelengthscloseto12μm,resultinginastrongphonon-polaritonresponseandahighextinctioncoefficientwithintheatmosphericwindow.Thisgivesthematerialathermalemissivity(εAW)of96.5%,allowingittoactasahighlyefficientthermalradiatortothecolduniverse.Thematerial’sopen,poroussurfacefurtherensuresthatthishighemissivityismaintainedacrossawiderangeofviewingangles,makingitscoolingperformancerobustandomnidirectional.9

Thepracticalbenefitsofthismaterialaresubstantial.Inreal-worldtestingonbuildingroofsinChina’sHongKong,thecoolingceramicconsistentlyreducedindoortemperaturesbyupto2.5°Cwithoutairconditioningandslashedcoolingenergyconsumptionbymorethan20%whenairconditioningwasused.Energysimulationssuggestthatintropicalregions,wherecoolingneedsaregreatest,thistechnologycouldreduceannualenergyuseinbuildingsbyover10%.Theseenergysavingsareaccompaniedbyseveralotheradvantages:thematerialisinherentlyfire-resistant,enduringtemperaturesabove1,000°C;itresistsultravioletdegradationfarbetterthanpolymer-basedalternatives;andwhentreatedwithfluorine,itbecomessuperhydrophobic,enablingrainwatertocleanitssurfaceautomatically.10

Moreover,inhigh-temperaturescenariossuchasfires,thematerialpreventstheLeidenfrosteffect–aphenomenonwherewaterdropletsskidacrossextremelyhotsurfacesratherthancoolingthem–allowingeffectiveemergencycooling.Forarchitecturalintegration,theresearchteamalsodevelopedcoloredversionsthatretainhighreflectivityinthenear-infraredspectrum,offeringbothaestheticflexibilityandthermalperformance.11

Thiscombinationofpropertiespositionsthecoolingceramicasaversatile,durable,andscalablesolutionforsustainablebuildingdesign.Byleveragingpassivecoolingprinciplesandbiologicallyinspiredstructures,thistechnologyrepresentsasignificantsteptowardreducingourrelianceonenergy-intensivecoolingsystemsandmitigatingurbanheatislandeffects–allwhileworkinginharmonywiththenaturalenvironment.TheremarkablywhitescalesoftheCyphochilusbeetle,whichachievetheirintensewhitenessthroughsophisticatedporousnanostructuresratherthanpigments,providedthebiologicalblueprintforabreakthrough.[Meaning]:TheextraordinarilywhitescalesoftheCyphochilusbeetleowetheirbrightwhitenessnottopigments,buttointricateporousnanostructures.Thisnaturaldesignservedasthebiologicalblueprintforatechnologicalbreakthroughincoolingmaterials.[Knowledgefocus]The“porousnanostructures”mentionedhereareacoreconceptinbiomimeticmaterialsscience.Thebeetle’sscalespossessa

hierarchicallyporousstructure,rangingfromnanoscaletomicroscale,whichefficientlyscattersvisiblelightofallwavelengths.Thisresultsinexceptionalwhitenessandreflectivitywithoutrelyingonchemicalpigments.Thisnaturaldesignprincipleinspiredthedevelopmentofthecoolingceramicdescribedinthearticle.[Words&Phrases]Theexpression“achievethrough...ratherthan...”means“accomplishsomethingbymeansofonemethodorfeature,insteadofanother(通过…而非…实现…).”e.g.

Thedeviceachieveshighefficiencythroughadvancedalgorithmsratherthansimplyincreasingpower.Theresultisaremarkablesolarreflectivity(𝑅ₛₒₗₐᵣ)of99.6%,meaningthematerialreflectsnearlyallincidentsunlightfromtheultraviolet(250nm)tothenear-infrared(2,500nm).[Meaning]：Theoutcomeisanextremelyhighsolarreflectivityof99.6%.Thisindicatesthatthematerialsendsbackalmosteveryrayofsunlightthathitsit,acrossabroadrangeofwavelengths.[Words&Phrases]Inscientificandpopularsciencewriting,evaluativeadjectivessuchas“remarkable”areoftenusedtoemphasizethesignificanceofascientificresultoranoutstandingpropertyofamaterial.e.g.Thenewcatalystshowsremarkablestabilityunderhigh-temperatureconditions.Inreal-worldtestingonbuildingroofsinChina’sHongKong,thecoolingceramicconsistentlyreducedindoortemperaturesbyupto2.5°Cwithoutairconditioningandslashedcoolingenergyconsumptionbymorethan20%whenairconditioningwasused.[Meaning]：InpracticalexperimentsonrooftopsinChina’sHongKong,thecoolingmaterialreliablyloweredthetemperatureinsidebuildingsbyasmuchas2.5°Cwithoutairconditioning.Whenairconditioningwasrunning,itcuttheenergyneededforcoolingbyover20%.[Words&Phrases]Theword“slash”means“tocutorreducesth.greatlyordramatically.”Intechnicalwriting,theuseofsuchaverbservesto

maketechnicalachievementsmorevividandaccessibletogeneralreaders.e.g.Thesoftwareupdateslashedthesystem’sprocessingtimefromseveralhourstojustminutes.Moreover,inhigh-temperaturescenariossuchasfires,thematerialpreventstheLeidenfrosteffect–aphenomenonwherewaterdropletsskidacrossextremelyhotsurfacesratherthancoolingthem–allowingeffectiveemergencycooling.[Meaning]:Furthermore,inextremeheat,likeduringafire,thismaterialstopstheLeidenfrosteffectfromoccurring.Thiseffectmakeswaterdropletshoverandglideoveraveryhotsurfaceinsteadofabsorbingheatfromit.Bypreventingthis,thematerialenableswatertocoolsurfaceseffectivelyinemergencies.[Knowledgefocus]The

Leidenfrosteffect

isaphenomenoninthermodynamics.Whenaliquidcomesintocontactwithasurfacemuchhotterthanitsboilingpoint,itinstantlyvaporizesatthepointofcontact,forminganinsulatingvaporlayer.Thislayerliftsthedroplet,causingittoskidacrossthesurfaceanddrasticallyreducingheattransfer.Thecoolingceramic’ssurfaceproperties(e.g.,porosityortreatedsurface)disrupttheformationofthisvaporlayer,allowingwatertomaintaindirectcontactwiththehotsurfaceandabsorbheatefficiently,whichservesasacriticalfeatureforfirefightingandemergencycoolingapplications.Thespecializedterm“theLeidenfrosteffect”isimmediatelyfollowedbyadefinitionsetoffbydasheswhenitisfirstintroduced.Thisisa

commonpractice

inscientificandtechnicalwritingtoensurethatreadersunderstandkeyconceptswithoutinterruptingthereadingprocesstoconsultaglossaryorexternalsource.Thiscombinationofpropertiespositionsthecoolingceramicasaversatile,durable,andscalablesolutionforsustainablebuildingdesign.[Meaning]:Havingallthesedifferentqualitiestogetherestablishesthecoolingceramicasaflexible,long-lasting,andeasilymass-producedoptionfordevelopingenvironmentallyfriendlybuildings.[Words&Phrases]Thephrase“position...as...”means“toestablish,present,orcausesomethingtobeseeninaspecificroleorcategory(将…定位为…).”e.g.Thecompany’smarketingcampaignaimstopositionitsnewdeviceasanessentialtoolformodernprofessionals.Theword“scalable”isusuallyusedtodescribeabusinessorsystemthatisabletogrowortobemadelarge(〔商务或系统〕可扩增的).Inthiscontext,itmeans“capableofbeingexpanded,manufactured,orimplementedefficientlyonalargerscalewithoutaproportionalincreaseincostorcomplexity.”e.g.Foralaboratorydiscoverytobecomeacommercialproduct,itmustfirstbeturnedintoascalablemanufacturingprocess.用于被动日间辐射制冷的仿生陶瓷1

随着全球能源需求持续攀升，尤其是在更温暖地区，人们对传统空调可持续替代方案的需求从未像现在这样迫切。一项颇具前景的解决方案却源自一个意想不到的领域：被动辐射冷却，一种自然过程，通过向太空辐射热量而不消耗能量来使表面冷却。这种现象一直都在发生——在霜冻的早晨，当露珠在树叶上形成时，或者在晴朗的夜晚，当露天物体比周围的空气更冷时。这些例子说明了地球如何通过大气层向太空发射红外辐射来实现冷却，特别是在8至13微米这个特定波长范围内，即所谓的“大气窗口”。2尽管辐射制冷的概念已存在数十年，但其实际应用——尤其在白天——始终面临重大挑战。任何被动辐射制冷材料的效能都很大程度取决于两个关键的光学特性：高太阳反射率以最小限度吸收来自太阳的热量，以及在大气窗口内的高热发射率以最大限度向太空散热。过去几十年中，研究人员始终难以开发出同时在这两种特性上都表现出色的材料。传统方法通常采用金属银基反射层，仅能反射约90%的入射太阳辐射。这在白天时段被证明是不足的，这时太阳强烈的辐射会压制其制冷能力。这种局限性使得多数传统辐射制冷装置仅能于夜间使用，然而实际上制冷需求的高峰恰恰出现在白天。3正是这一挑战促使研究人员突破传统设计框架，转向自然界寻求解决方案。白甲虫异常洁白的鳞片呈现出的极高白度并非来自色素，而是源于其精巧复杂的多孔纳米结构——这为技术突破提供了仿生设计蓝本。通过模仿这种自然设计，科学家们研制出一种新型冷却陶瓷材料，该材料从根本上重构了材料调控太阳辐射与热发射的方式。4这项具有突破性意义的分级层次结构冷却陶瓷的研制工作，是由香港城市大学能源与环境学院的曹之胤教授（通讯作者）领导完成的，林凯昕教授为第一作者。他们的合作研究成功地开发出了一种具有卓越光学特性的陶瓷材料，这对实现高性能被动日间辐射制冷至关重要。5冷却陶瓷的卓越光学性能源于材料特性与多尺度结构工程的精妙结合，实现了接近理想状态的日间被动辐射制冷效果。其核心材料，α-氧化铝，是基于其固有的电磁特性来选择的。具有7.0eV的宽带隙值——远高于太阳光谱中光子能量的上限（约4.13eV的紫外辐射），该材料在整个太阳光谱范围内展现出极低的消光系数。这一根本特性确保了其对阳光的最小吸收，为实现高反射率奠定了极其重要的基础。6然而，要实现近乎完美的太阳光反射，需要的不仅仅是一种非吸收性材料；还需要对太阳光谱中所有波长的光进行高效散射。这是通过一个分级多孔结构来实现的，该结构模拟了白甲虫鳞片的光散射机制。该冷却陶瓷包含着从纳米级到数微米级的孔隙结构。这种多尺度孔隙结构对于在宽波段范围内引发强烈的米氏散射至关重要。直径约200-300纳米的较小孔隙因其尺寸与可见光和紫外光的波长相当，能够有效地散射这些波段的光。同时，微米级的较大孔隙则会散射近红外辐射，这种辐射在太阳能量中占有相当大的比例。7其结果是，该材料实现了高达99.6%的太阳反射率（𝑅ₛₒₗₐᵣ），这意味着从紫外线（250纳米）到近红外线（2,500纳米）的几乎全部入射太阳光都能被反射出去。这一性能使其跻身迄今已知最白、反射率最高的陶瓷材料之列，将太阳热增益降低到前所未有的程度，使（材料）表面即便在强烈太阳辐射下仍能保持低于周围空气温度的状态。8与此同时，这种冷却陶瓷还必须通过地球大气窗口（8—13微米）高效地向外辐射累积的热量。这得益于氧化铝的另一项固有特性：其原子键的振动模式。铝—氧键在接近12微米的波长处产生共振，从而在大气窗口内形成强烈的声子—极化激元响应，并具有高消光系数。这使得该材料的热发射率达到96.5%，能够像一个高效的热辐射体一样，将热量辐射到寒冷的宇宙空间。该材料开放式的多孔表面结构进一步确保了这种高发射率在宽广的视角范围内得以维持，使其制冷性能稳定可靠且具有全向性。9这种材料的实际应用价值十分显著。在中国香港地区的建筑屋顶实测中，该冷却陶瓷在不开启空调的情况下可持续降低室内温度最高达2.5℃，而在启用空调时，则可削减超过20%的制冷能耗。能源模拟结果表明，在制冷需求最高的热带地区，此项技术可使建筑物的年度能耗减少10%以上。除了节能之外，该材料还具有一些其他的优势：本身具备耐火特性，可耐受超过1000℃的温度；其抗紫外线老化远优于聚合物基替代材料；经氟化处理后，更呈现超疏水特性，使雨水能够自动清洁其表面。10此外，在火灾等高温场景中，该材料还能防止莱顿弗罗斯特效应——即水滴在极热的表面快速滑移，而非对这些表面进行冷却的现象，从而实现有效的紧急降温。针对建筑应用需求，研究团队还开发了彩色版本，这些材料在近红外光谱区仍能保持高反射率，从而兼顾建筑美观性与隔热性能。11这些特性的结合，使冷却陶瓷成为一种兼具多功能性、耐用性和可规模化应用潜力的可持续建筑设计解决方案。通过利用被动冷却原理与受生物启发的结构，这项技术意味着我们朝着减少对高能耗制冷系统的依赖和缓解城市热岛效应迈出了重要一步——所有这一切，都在与自然环境和谐共生中实现。Readthepassageandcompletetheoutlinewithinformationfromthepassage.ReadingandsynthesizingBiomimeticceramicsforpassivedaytimeradiativecoolingI.TheglobalchallengeandtheinspirationfromnatureTheincreasingglobaldemandforcooling,especiallyinwarmclimates,highlightsanurgentneedfor1)________________

_______________toenergy-intensiveairconditioning.sustainablealternativesPassiveradiativecoolingcanbeapromisingsolution.Itisanaturalprocessthatreleasesheatintospacebyemittinginfraredradiationthroughtheatmosphere,especiallywithinthe2)___________________.II.LimitationsofprevioustechnologicalattemptsEarlyattemptstocreateradiativecoolingmaterialsfacedasignificantlimitation:Theycouldnotachievesufficientlyhighsolarreflectivitytobeeffective3)______________________________________,whencoolingdemandishighest.atmosphericwindowduringthedaytime/duringdaylighth