简介:ThepropertiesandmechanismofconcreteunderwaterleakagecorrosionwerestudiedintermsofthedissolutionofcalciumoxideandsiliconoxidefromconcreteandthevariationofpHvalueofpermeatewater.Theexperimentalresultsshowthattheamountofcalciumoxideandsiliconoxidedissolvedfrompercubicmeterofconcretegraduallydecreasewithpenetrationtimeandultimatelystabilizeatacertainvalue.ThepHvalueofpermeatewaterdescendalongwithpenetrationtime.Thedurabilityofconcreteunderleakagecorrosionwasanalyzedbyaformulafittedonthedissolvedamountofcalciumoxide.
简介:ShapeMemoryAlloy(SMA)opticallyactivatedisthekeylechnologyofopticalSMAactivator,AccordingtotheshapememorymechanismofSMA,researchesaredoneontheactivatingresponsetimeandlightwavelengthofactivatingsourceelcofSMAopticallyactivatedtoapproachtheparameterswelectionofopticalactivation,SMAhastheoptimumefficiecyintherageof13secondsto27secondswhenSMAisilluminatedcontinuslybywavelengthof675nm;ThepoweroflightwavehasaloweffectonSMA;thelongertheactivatingwavelenth,thequickertheresponsetimeofSMAactivated,Iftheproperactivatingtimeandactivatingwavelength,areadopted,andthestructuredeformationofcompositematerialofSMAimbeddedmaybeactielycontrolled,andidealeffectwillbegotten,TheresarchprovidesanevdenceforthedesignofopticalSMAactivatorandisofgreatsignificncetoitsapplication,Theresarchonsmartstructurehasawideapplicationprospect.
简介:NitridingisemployedforthehardFeelectrodepositiontoproduceahard-facingandantiwearcoating.Itonlytakes1hforthehardFecoating,whichismuchshorterthannitridingtheFeandsteel.Theresultsshowedthatthenitridingcanincreasethemicrohardness,wearresistanceofthecoating,aswellasthebondingstrengthofthecoatingwiththesubstrate.Additionallyitcaneliminatethebrittleness,turntheinternalstressofthecoatingfromtensiontocompression.ThewearresistanceofthenitridedFecoatingis4.6timesashighasthatofCrcoating.ItissimpleandeconomictocombinehardFeelectroplatingandnitriding,whichisagoodtechnologyofthetribologicalsurfacemodification.
简介:Thisresearchfocusedonusingthewasterubberpowderasakindofregenerateresourcestoimprovethemechanicalpropertiesofcementmortar.ThetwokindsofhybridmodifiedrubberpowderTRPandATRPwerepreparedbysol-gelmethodandthenusedincementmortar.Thestructuresandpropertiesofthemwerestudied.ItisshownthatthenanoSi-O-SinetworkisgeneratedinTRPandATRPnetworksandthehydrophilicgroupisgraftedonthesurfaceofATRP.Themechanicalpropertiesofrubber-treatedmortar(RTM)weretestedandthemicrostructuresofthemwerealsostudied.Comparedtothemortarswithunmodifiedrubberpowders(RP),NaOHtreatedrubberpowder(SRP)andcouplingagenttreatedrubberpowder(CRP),theRTMwithATRPhasthehighestcompressivestrengthandflexuralstrength.Thestress-straincurvesshownthatthepeakofstressofRTMwithATRPisincreasedandindicatedthehighercompressiondeformationandtoughness.ItisfoundthattheinterfacialadhesionbetweentheATRPandcementmortarisincreaseddistinctlybySEM,whichresultsinenhancedductilityandmechanicalpropertiesofRTMwithATRP.
简介:Highentropyalloyhasattractedincreasingattentions.However,toenhancethealloystrengthoftenleadstoimpairmentoftheductility,orviceversa.HerewereportedaheattreatmentapproachonAlCrFeNi2Ti0.5highentropyalloy,whichcanelevatethestrengthandductilitysimultaneously.AningotofAlCrFeNi2Ti0.5weighing2.5kgwasfirstlyfabricatedbymediumfrequencyinductionmelting.Thensamplesfromthesameheightofthebulkingotwereannealedfor6hat600,700,800and1000℃,respectively.After1000℃annealing,anoptimalmicrostructurewasobtainedbyusingourapproachwhichcanmakesomeprecipitationparticlesdistributehomogeneouslyinthedendriteinteriorwhilekeeptheinterdendritestructureasasinglesolidsolutionphase.ThemechanicaltestonthisAlCrFeNi2Ti0.5alloysampleshowedthat,thecompressivefracturestrengthσbcwasincreasedbyabout600MPaandtheplasticstrainepwasdoubled,comparedwiththoseoftheas-castsample.Ourapproachcanbereadilyadaptedtolarge-scaleindustrialproductionofhighentropyalloyswithhighstrengthandductilitybyproperannealingtreatment.
简介:Bonedefectisoneofthemostcommondiseasesinclinic.Existingtherapeuticapproacheshaveencounteredmanyproblems,suchaslackofautogenousallogeneicboneandimmunologicalrejectiontoallogeneicimplant.Synthetichydroxyapatite(HA)providedsolutionsforbonerepair,sincetheHAisthemaininorganiccomponentofanimals'bone.AlthoughHAhasgoodbiocompatibility,butonlythelimitedosteogeniccapability,whichisofsignificanceformodernbonerepairmaterials.Siisanessentialtraceelementinbonetissue,andithasbeendemonstratedtobeabletopromoteboneformation.Therefore,silicate-dopedhydroxyapatite(Si-HA)mayserveasapromisingmaterialforbonerepair,andpromoteboneregenerationintherepair.ThecurrentreviewdiscussesdevelopmentofSi-HA,focusingonitspreparationandcharacterization,invitroandinvivoevaluationsofthematerial,positiveeffectofSi-HAonpromotingboneformationinclinicalapplications,andmolecularmechanisminvestigationofsuchpromotiveeffect.
简介:TiO2nanometerthinfilmswithphotocatalyticantibacterialactivitywerepreparedbythesol-gelmethodonfusedquartzandsodalimeglassprecoatedwithaSiO2layer.ThethinfilmswerecharacterizedbyX-rayphotoelectronspectroscopy(XPS),scanningelectronmicroscopy(SEM),andX-raydiffraction(XRD).TheresultsshowthatsodiumandcalciumdiffusionintonascentTiO2filmiseffectivelyretardedbytheSiO2layerpre-coatedonthesodalimeglass.Theantibacterialactivityofthefilmswasdetermined.ThecrystallineofTiO2nano-meterthinfilmhasimportanteffectsontheantibacterialactivityofthefilm.
简介:Theshrinkagecharacteristicsofexpansiveconcretefilledsteeltube(CFST)areanalyzed,Coldshrinkage,creepandautogenousshrinkageareconsideredasthemainreasonsofcausingCFSTcontraction.InaccordancewiththeshrinkagecharacteristicsofexpansiveCFST,akindofenergy-storeddelayedexpansiveagentisexploited,whichcannotonlycompensatetheshrinkageofthecoreconcreteineverystages,butalsomakeCFSTexpandaccordingtothedelayedexpansionmechanism.Astheresult,theprestresslosswillbereducedandexpansiveenergywillbeutilizedeffectively.
简介:这些电影的容易的磁化轴与底层平行,这被发现,并且同样劈啪作响、退火的multilayers的磁性在电影飞机是各向同性的。强制的地H//c是4.8kA/m,remanence-to-saturation磁化M//r/M//s的比率是大约0.73为作为--劈啪作响的样品。H//c和M//r/M//s增加温度,增加退火,特别当退火的温度比400度C高时。这些试验性的结果能被使用联合的铁磁性的交换和coercivity的卡住的理论解释。(编辑作者摘要)13个裁判员。
简介:Polyacrylate-basedconductivecoatingswerepreparedfrompolyacrylateemulsionasmatrixandcarbonblack(CB)whosesurfacewastreatedwithtitanatecouplingagentasconductingparticles.OnekindoforganiccrystalwasaddedtostudyitseffectsontheelectricalconductivityandPTC(positivetemperaturecoeffi-cient)effectoftheconductivecoatings.ExperimentalresultsshowthatthecoatingscontainingonlypolyacrylateemulsionandCBexhibitanexcellentelectricalconductivitybutbadPTCeffect,andwhenorganiccrystalisadded,PTCeffectischaracterizedandcanincreaseby2ordersofmagtitude.Thecriticaltransformationtemperatureofpolyacrylateemulsion/CBPTCcompositesisdecidedbymeltingpointoforganiccrystals.
简介:Aseriesofsolarradiationtestsforthepolytetrafluoroethylene(PTFE)bulkandfilmsampleswerecarriedoutusingQ-SUNXE-3-HSCtypeSolarRadiationSimulator,withthetestparametersasfollows:radiationintensityis1120W/m~2,temperatureis55℃andhumidityis70%RH.Surfacemorphology,compositionandmicrostructureofthePTFEsamplesbeforeandafterradiationtestswerecharacterizedcontrastively.EffectofsolarradiationonthetribologyandwettingpropertiesofPTFEwerealsostudiedbytribometerandcontactangletester,respectively.Theresultsshowthat,forradiatedPTFE,surfaceroughness,therelativecontentofCelement,thefrictioncoefficientsandthecontactanglewithwaterincreasedinvaryingdegrees.Inconclusion,theobviouschangeinPTFEsamplescanbemainlyattributedtobreakof(CFx)-CbondsafterbombardmentofhighenergyUVphotons,whichcausesthelossofF-richgroups,oxidation,crosslinkingandrestructuringofactiveunsaturatedgroups.
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简介:模仿的austempered的一张连续冷却转变(CCT)图可锻的铁(ADI)焊接金属借助于Formastor-F图测量仪器被开发了,并且由与实际焊接作比较修订了。最后,修订的图被用来决定焊接技术。(编辑作者摘要)4个裁判员。
简介:Inordertostudythestresscorrosioncracking(SCC)ofX70pipelinesteelanditsweldjointinacidsoilenvironmentofsoutheastofChina,twosimulatingmethodswereusedhere.Theonewastoobtainthebadmicrostructuresinheataffectedzonebyannealingat1300°Cfor10minandaircoolingtoroomtemperature,theotherwastogetaseriesofsimulatingsolutionsoftheacidsoilenvironment.SCCsusceptibilitiesofX70pipelinesteelsbeforeandafterbeingnormalizedinthesimulatedsolutionswerestudiedbyslowstrainratetest(SSRT)andmicrostructuralobservationoffractureareas.Potentiodynamicpolarizationcurveswereusedtostudytheelectrochemicalbehaviourofdifferentmicrostructures.SCCdoesoccurtoboththeas-receivedmaterialandnormalizedmicrostructureafterheattreatmentasthepolarizationpotentialdecreased.Hydrogenembrittlement(HE)isindicatedoccurringtoalltestedmaterialsat-850mV(vsSCE)and-1200mV(vsSCE).TheSCCmechanismsaredifferentwithinvaryingpotentialrange.Anodicdissolutionisthekeycauseaspolarizationpotentialhigherthannullcurrentpotential,andHEwillplayamoreimportantroleaspolarizationpotentiallowerthanthenullcurrentpotential.
简介:λ-MnO2waspreparedbycolumnmethodfromnormalspinelLiMn2O4withpurityof99.38%.TheinfluenceofLiMn2O4grainsizeandacidityofleachingsolutiononthelithiumleachingprocesswasstudied.TheresultsshowthattheappropriaterangeofLiMn2O4grainsizewas60-160meshesandtheconcentrationofleachingsolutionHClwas0.1mol·L-1.TheadsorptioncapacityQofλ-MnO2forlithiumincreasedwiththeincreaseofpHandchangedmarkedlyatpH6.0-10.0.Itwas3.80mmol/gatpH12.0.ThedistributioncoefficientsKdofLi+andNa+were3.406×104and2.300respectively,andtheseparationcoefftcientaLiNawas1.481×104atpH6.5.Asaresult,λ-MnO2isahighperformanceion-sievematerialforlithiumion.