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简介：Reactionergodographyfortheadditionoflithiumhydridetoacetyleneindicatesthatthelithiumhydride,inbothmonomericanddimericforms,reactswiththeacetyleneviatwosimilarandcompetitivepathways.Hence,wehaveobtainedthepseudo-first-orderrateconstantofthisreaction.

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简介：LowcarbonsteelswithBandPadditionswereremeltedbyelectromagneticlevitationandsolidifiedinavacuumdroptube.Thedropletvolumesweresettobe2mm×2mm×2mm(TM)and5mm×5mm×5mm(FM),respectively.Themicrostructureofrapidlysolidifiedsteeldroplets(cooledinsiliconoil)withPandbothBandPadditionwasobserved.ThemicrostructuresofB-bearingdropletsamplesweremoreuniformthanthoseofB-freeones,forbothTMandFMsamples.Thedistributionof℃andPalongthediameterofeachsamplewasdetected.Thewell-distributionof℃andPwasdetectedinB-bearingdropletsamples.SoitcouldbededucedthatBwasalsowelldistributedinthesteels.ItwasBatomsthatpromotedthewell-distributionof℃andP,whichfurtherimprovedtheuniformityofmicrostructureundertheconditionofrapidsolidification.Themicro-hardnessofBbearingsampleswashigherthanthatofB-freesamples,andthehardeningmechanismwasdiscussedindetail.

简介：Niobium,asthemosteffectivesecond-phaseformingelement,wasaddedintheFe-Cr13-C-Nhard-facingalloytogetcarbonitrideprecipitates.Morphologyandcompositionofcarbonitrideinthehardfacingalloywerestudiedbyopticalmicroscopy,scanningelectronmicroscopy,andelectronprobemicroanalyzer.Thether-modynamicsandtheeffectonthematrixoftheformationofcarbonitridewerealsodiscussed.ItwasfoundthatniobiumcarbonitridesarecomplexNb(C,N)precipitatedistributedongrainboundaryandmatrixofthehardfacingalloy.Underas-weldedcondition,primarycarbonitrideparticleswerereadilyprecipitatedfromthehardfacingalloywithlargesizeandmorphologyastheywereformedalreadyduringsolidification.Underheattreatmentcondition,alargenumberofsecondarycarbonitridescanpre-cipitateoutwithveryfinesizeandmakeagreatsecondaryhardeningeffectonthematrix.Asaresult,additionofniobiuminthehardfacingalloycanpreventtheformationofchromium-richphaseongrainboundariesandinter-granularchromiumdepletion.

简介：钻石粒子增强了铝硅矩阵composites，作为艾尔(Si)/diamondcomposites缩短了，被制作由压榨扔。微观结构和composites的机械性质上的Si内容的效果被调查。机械性质被发现monotonically增加，Si内容增加直到7.0?wt%。Al-7.0?wt%Si/diamond合成展览78的张力的力量?MPa，230的弯曲力量?426的MPa，和压缩力量?MPa。Al-Si最容易溶解的阶段被显示紧与艾尔矩阵和钻石粒子连接，它为在艾尔(Si)/diamondcomposites的机械性质的改进负责。

简介：Lowercontentofcarboncanfurtherimprovethestressrupturelifeofp-modifiedDA718alloyuptomorethan270%.Meanwhile,theductilityofthealloydecreasedalittle.Moreboronatomsdissociateduetodecreasingcarboncontentandinteractwithphosphoruswhichbringsthelongerstressrupturelifeofthealloy.Lesscarbonmayinducemorephosphorussegregatinginthegrainboundaryandresultinbrittleness.

简介：Tensiledeformationandfracturecharacteristicsofpolyimide/montmorillonitenanocompositefilmsareinvestigatedtoenhancetheparticularmechanicalpropertiesandunderstandtheeffectivefactorsindominatingthemechanicalpropertiesofnanocomposites,suchasthenanolayer,matrixandnanolayer/matrixinterface.Howtocontributetothemechanicalpropertiesofnanocompositefilmisaverycomplexproblem.Inthispaper,thesefactorsareanalyzedbasedontheadditionamountandfracturemechanics.Theresultsindicatethatthespecimenat20wt%MMTbreaksprematurelywithafracturestrength(σb=78MPa)muchlowerthanthat(σb=128MPa)atthe1wt%MMT.However,theYoung'smodulus(3.2GPa)oftheformerishigherthanthat(1.9GPa)ofthelatter.Fractographyalsoindicatesthatthebrittlecrackingformedinhighcontentadditionisthemaincauseoffailurebutmicroscopicallyductilefracturemorphologystillexistslocally.Andforthetraceelementaddition,thesmallerthreadingslippingveinsareevenlydistributedontheentirefracturesectionofthesefilms.Therefore,thesecharacteristicswouldpresumablybeassociatedwithboththeconcentrationeffectsofsizeofnanocompositesheetsandtheincreasingdeformationharmonyinnanolayers.

简介：MINDO/3MOmethodhasbeenusedtostudythemechanismoftheconsecutiveadditionofHCNtopropionitrile.Theresultsobtainedforthefirstfivestepsshowthatthereactionisexothermic,andstep1istheratedeterminingstep.

简介：Inordertoimprovethecompressivestrengthofxonotlite,thepretreatedquartzpowder,slakedCaO,additive,deionizedwater(water-solidratioof30)wereplacedinamagneticallystirredautoclave,andthecorrespondingproductswereobtainedafterincubatingat220℃for0,1,3and6h,respectivelytoexplorethesyntheticprocessofxonotlite.Inthepreparedxonotlitepowder,0,5%,10%,15%and20%(bymass,thesamehereinafter)ofpre-treatedceramicstaplefiberswereadded,andtwosetsofspecimenwiththespecificationsofφ50mm×35mmweremoldedbypressedfiltration.Onesetofspecimenswerenotsintered,andtheothergroupwasfiredat1000℃for2htoexploretheeffectofceramicfiberadditiononthecompressivestrengthbeforeandaftersinteringofxonotlite.TheresultsshowthatC-S-Hgelisfirstsynthesizedinthesynthesisofxonotlite,andthentheC-S-Hgelistransformedtoformtobermlite,atlasttobermlitefullyreactstoproducexonotlite.Theadditionofceramicfiberenhancesthecompressivestrengthofthexonotlitebeforeandaftersintering.Whenthe15%ceramicfiberisadded,thecompressivestrengthisthehighest.Thespecimensbeforeandafterthehightemperaturefiringcontainxonotlitephaseandcalciumsilicatephase,respectively,andthecompressivestrengthofthefiredspecimensishigherthanthatofthegreenones.

简介：Anirradiationgraftingmethodwasappliedforthemodificationofnanoparticlessothatthelattercanbeaddedtopolymericmaterialsforimprovingtheirmechanicalperformanceusingexistingcompoundingtechniques.Thefollowingitemsarediscussedinthispaper:(a)chemicalinteractionbetweenthegraftingmonomersandthenanoparticlesduringirradiation,(b)propertiesincludingmodulus,yieldstrength,impactstrengthandfracturetoughnessoftheresultantcomposites,and(c)possiblemorphologicalchangesinducedbytheadditionofnanoparticles.Throughirradiationgraftingpolymerization,nanoparticleagglomeratesturnintoanano-compositemicrostructure(comprisedofthenanoparticlesandthegrafted,homopolymerizedsecondarypolymer),whichinturnbuildsupastronginterfacialinteractionwiththesurrounding,primarypolymericmatrixduringthesubsequentmixingprocedure.Duetothefactthatdifferentgraftingpolymersbroughtaboutdifferentnanoparticle/matrixinterfacialfeatures,microstructuresandpropertiesoftheultimatecompositescouldthusbetailored.Itwasfoundthatthereinforcingandtougheningeffectsofthenanoparticlesonthepolymermatrixcanbefullybroughtintoplayataratherlowfillerloadingincomparisontoconventionalparticulatefilledcomposites.

简介：Theadditionofsodiumperfluoroalkanesulfinates（RFSO2Na）tovariousolefins（CH2=CHR）initiatedbyFentonreagent(Fe2+-H2O2)inthepresenceofsodiumazidegavetheadduetsRFCH2-CHN3Ringoodyield.AradicalmechanismwasproposedbasedontheEPRandotherevidences.TheadductswerereadilyreducedthroughcatalytichydrogenationtogivethecorrespondingaminesRFCH2CH（NH2）Rinhighyield.Thereactionrepresentsaconvenientandeffectiveroutetotheseusefulorganofluorinecompounds.

简介：Micro-/nanocrystallinediamondfilmsdepositedinAr/H2/CE4microwaveplasmashavebeenstudied,withargonflowratesintherangeof70-100seem.Theeffectsofargonadditiononmorphology,surfaceroughness,qualityandstructurewereinvestigatedbyscanningelectronmicroscopy,surfaceprofiler,RamanspectrometerandX-raydiffraction（XRD）.Itisdemonstratedthatwhentheargonflowrateis70sccmor75sccm,well-facetedpolycrystallinediamondfilmscanbegrownatalowsubstratetemperaturelessthan610℃.Withtheincreaseintheargonflowrate,thesmoothcrystallographicplanesdisappeargradually.Instead,roughcrystallographicplanesmadeupofsmallaggregatesbegintotakeshape,resultingfromtheincreaseinthesecondarynucleationrate.Nanocrystallinediamondfilmswereobtainedataflowrateof100sccm,andalloftheprepareddiamondfilmsweresmooth,withasurfaceroughness（Ra）lessthan20nm.Ramananalysesrevealthattheamountofamorphouscarbonincreasessignificantlywiththeincreaseinargonflow.TheresultsofXRDshowthatcrystallinesizeandpreferentialorientationofdiamondfilmsdependontheargoncontentintheplasmas.

简介：Afacileandefficient1,4-conjungateaddition(Michaeladdition)reactionofactivemethylenecompoundstoα,β-unsaturatedcompounds,catalyzedbyguanidiniumlactateionicliquid(IL9),hasbeendeveloped.Arangeofchalconesandnitroalkenestogetherwithactivemethylenecompoundshavebeenconvertedsmoothlytothecorrespondingproductsinhighyields.

简介：Ifthegivenequationsaresuchthatthecoefficientsofoneofthevariablesarenumericallyequalinbothequations,itispossibletoeliminatethevariablebyadditionorsubtraction.假设已知的两个方程中有一个变量的系数相等，那么就可以用加法或减法消去一个变量．

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简介：Additionofrareearth（RE）suchasYinthesurfacelayerofgraycastironorNi-basedsuperalloybylasersutfacemeltingwascarriedoutusinga2kWCO2laser.FordeliveringtheelementYtothemetalsurfacedur-inglaserirradiation,severalmethodswereemployed.ItisfoundthatY-containingsurfacemodifiedlayercanhecontrollablyobtainedonsubstrates,agraycastironcanbelasersurface-modifiedwithCr+Al-Ypowderre-sultinginathinlayerofFe-Cr-Al-Yalloysuchas30Fe40Cr27Al3Y.

简介：Thisstudyexaminesmechanismsforprovidingnucleitoequiaxedgrainsintheweldsofpureferriticstainlesssteel(FSS).TheadditionofthealloyelementTitopureFSS439causestheprecipitationofTiN,whichcanbenefitthecolumnar-to-equiaxedtransition(CET)ofgastungstenarcwelding(GTAW).Meanwhile,theinitialmorphologyoftheprecipitates,theconcentrationmultiplicationsofTi,N,etc.ofFSS439shouldbecontrolledtoinducetheformationofCETduringtheshortweldingprocess.

简介：ThehotductilityofFe-36NiinvaralloywithdifferentadditionsoftheelementceriumwasinvestigatedusingaGleeble-3800thermal-mechanicalsimulatoroverthetemperaturerange850-1050℃,andtheimprovementmechanismofthehotductilitywasanalyzedusingacombinationofSEM,EDS,andOM.TheresultsindicatedthatFe-36Niinvaralloyexhibitedpoorhotductilitybelow1050℃,whichwasmainlyattributedtoweakgrainboundariesandtheactionofgrainboundarysliding.However,thealloyswithceriumcontentsof0.016%and0.024%bothdemonstratedsubstantialimprovementinthehotductilityovertheentiretestingtemperaturerange.Theobservedimprovementofthehotductilityofthealloywith0.016%ceriumat950℃andthealloywith0.024%ceriumat900℃wasassociatedmainlywiththegrainboundarystrengtheningandtherestrictionofthegrainboundaryslidingbecausetheadditionofceriumreducedthesegregationofsulfuratgrainboundariesandrefinedthegrainstructure.Theoccurrenceandaccelerationofdynamicrecrystallizationwerefoundtoberesponsibleforthehighhotductilityofthealloywith0.016%ceriumat1000℃andthealloywith0.024%ceriumat950-1000℃asaresultoftherefinementofthegrainstructurebyadditionofcerium.

简介：Easilyavailablechiralketoneswereemployedforthesynthesisofopticallyactivepyridylalcohols,whichwereappliedintheasymmetricdiethylzincadditiontoaldehydes,upto89.4%e.e.wasobtainedusingD-fructose-derivedpyridylalcohol.