简介：GypsumcrystallizationalongwiththesimultaneousregenerationofKClwasinvestigatedbythereactionofCaCl2solutionwithK2SO4.WelldevelopedsheetstructuregypsumcrystalswereproducedwhenK2SO4solutionwasaddedintotheCaCl2solutionbyslowtitrationorinmultiplestagesover2-8hfollowedby2hequilibration.InordertoregenerateKClsolutionasconcentratedaspossible,K2SO4solidwasaddedintothegivenCaCl2solutioninsteadofK2SO4solution,obtaininggypsumcrystalswithalmostthesamequalitybymultistageadditionwith[SO42-]/[Ca2+]molarrationolargerthan0.8.However,impurityofK2SO4·CaSO4·H2OwasdetectedbyXRDandwasfurtherconfirmedbySEM-EDSintheproducedcrystalswhenthe[SO42-]/[Ca2+]ratioincreasedto1.1.ItisprovedthatappearanceofthedoublesulfateisattributedtotherelativelyhighconcentrationofK2SO4.So,itisessentialtoproperlycontrolthe[SO42-]/[Ca2+]ratioandmakesure[Ca2+]inexcesstosuppressthesolubilityofCaSO4evenattheexpenseoflowcalciumremovalrate.

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简介：Thespecimenswerepreparedbymoldingthemixtureofsilicafume(w(SiO2)=94.5%;averageparticlesize:0.08μm)andsiliconnitride(≤0.074mm)withamassratioof11,carbonembeddedfiringat1300℃,1450℃,1500℃,1550℃and1600℃for3hinair,andthenwater-cooling,respectively.Themicrostructureandphasecompositionofthespecimenswereanalyzed.Theresultsshowthat:(1)silicafumereactsobviouslywithSi3N4formingSi2N2Oabove1550℃.TheedgesandcornersofSi3N4grainsbecomesmoothandtheSi3N4grainsdistributeinthecontinuouscementationphaseofSi2N2OformingthedensestructureofSi2N2OpackedSi3N4;(2)below1500℃,theedgesandcornersofSi3N4grainsareclear,Si2N2Odoesn'tform,andonlySiO2crystallizesfromsilicafumewhichhappensobviouslyat1300℃.

简介：氨基甲酸酯，硫安类药剂和乙酰胺到的intramolecularorganocatalyticenantioselectiveaza-Michael反应，不饱和的酉同类被开发。这个过程被9-amino-9-deoxy-epi-quinine和diphenyl氢磷酸盐支持与优秀enantioselectivity(92%-97.5%ee)和很好的收益(多达99%)负担得起几综合地有用的五成员、六成员的heterocycles的直接、迅速的合成。

简介：为有边界不安的反应扩散方程的非线性的起始的边值问题的一个班被考虑。在合适的条件下面并且用微分不平等的理论，起始的边值问题的asymptotic被学习。

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简介：APt-MoO3/Ccatalyst,aimedtoeliminatetheharmfuleffectofsulfurdioxide（SCb）ontheperformanceofPtnanoparticles（NPs）forcatalysisofoxygenreductionreaction（ORR）inprotonexchangemembranefuelcells（PEMFC）,isdevelopedandcharacterizedbyTEM,XRDandXPS.TheresultsrevealthatPt-MoO3/Ccatalystexhibitsnotonlyahighercatalyticactivity,butalsoabetterSO2poisoningresistanceandabetterrecoveryperformancethanthecommercialPt/Ccatalystdoes.

简介：Anovelporousbinderwasobtainedfromacid-treatedkaolin.Thisnewbinderpossessedabundantmeso/macropores,goodhydrothermalstabilityandheavymetalresistance.Thepreparedcatalystusingnewbinderfeaturedlowattritionindexandlargeporevolume.ThecatalystswerecontaminatedwithNi,V,andtestedinafixed-fluidizedbedreactorunit.Incomparisonwiththereferencesample,theoilconversionachievedbytheabove-mentionedcatalystincreasedby3.50percentagepoints,andheavyoilyielddecreasedby2.86percentagepoints,whilethetotalliquidyieldandlightoilyieldincreasedby2.82percentagepointsand0.79percentagepoints,respectively.Theperfectporestructure,goodhydrothermalstabilityandheavymetalresistantperformanceofnewbinderwerethepossiblecausesleadingtoitsoutstandingperformance.

简介：Anewreaction-controlledphase-transfercatalystsystem,lacunaryKegginpolyoxotungstate[C7H7N(CH3)3]9PW9O34hasbeensynthesizedandusedforcatalyticepoxidationofolefinswithH2O2astheoxidant.Infraredspectrawereusedtoanalyzethebehaviorofthephasetransferofcatalyst.Inthissystem,thecatalystnotonlycanactashomogeneouscatalystbutalsoasheterogeneouscatalysttobeeasilyfilteredandreused.Theepoxidarionreactioniscleanandexhibitshighconversionandselectivityaswellasexcellentcatalyststability.

简介：Inthispaper,weareconcernedwiththeexistenceanduniquenessofglobalsolutionsofthemodifiedKS-CGLequationsforflamesgovernedbyasequentialreaction,wheretheterm|P|~2Pisreplacedwiththegeneralizedform|P|~(2σ)P,see[18].Themainnoveltycomparedwith[18]inthispaperistocontrolthenormsofthefirstorderofthesolutionsandextendtheglobalwell-posednesstothreedimensionalspace.

简介：Thethermalbehavior,mechanismandkineticparametersoftheexothermicdecompositionreactionof3,3-bis(azidomethyl)oxetane/tetrahydrofuran(BAMO/THF)copolymerinamodehavebeeninvestigatedbymeansofDSC,TG-DTG,fastandlowerthermolysis/FrIRandTG-MS.Thereactionmechanismwasproposed.Theapparentactivationenergyandpre-exponentialconstantofexothermicdecompositionreactionofthecompoundat0.1MPaare167.04kJ·mol^-1and10^14.41s^-1,respectively.ThecorrespondingcriticaltemperaturesofthermalexplosionobtainedfromtheonsettemperatureTeandthepeaktemperatureTpare223.20and245.78℃,respectively.ThekineticequationoftheexothermicdecompositionprocessofBAMO/THFat0.1MPacouldbeexpressedas:dα/dT=10^15.19[-ln(1-α)^2/3e^-2.009×10^4/T

简介：Ithasbeenfoundthatthetwo-phasereactionsofaqueousHCl,HOAcorH3PO4withprimaryamineN1923inchloroformareosiclatingreactions.Theirpower-timecurvesweremeasuredbythetitrationmicrocalorimetricmethod,andtheinductionperiod(tin).Thefirstoscillatingperiod(tp.1)andthesecondoscillatingperiod(tp.2)weredetermined.Theapparentactivatingparametersandtheordersoftheoscillatingsystemswerecalculatedandthefollowingrelationshipswereestablished:fortheoscillatingsystemofhydrochloricacid.

简介：ApracticalprocedureforpalladiumcatalyzedSuzukicross-couplingreactionofarylboronicacidswitharylhalides,includingarylchloridesinmoltentetra-n-butylammoniumbromide(TBAB)wasdeveloped.Thereactionexhibitshighefficiencyandfunctionalgrouptolerance.Therecoveryofthecatalystandmoltenn-Bu4NBrwasalsoinvestigated.

简介：利用Gaussian94节目包裹，涉及o-pyridyl基的分解反应的所有种类在B3LYP/6-311++G*充分被优化*水平。内在的反应坐标计算被采用证实转变状态和产品的连接，并且转变状态被想象的频率(0或1)的数字查明。反应机制被震动的模式分析和电子人口分析阐明，并且反应率常数与转变状态理论是计算的。

简介：Thisworkreportsafeasiblesynthesisofhighly-dispersedPtandPt-Fenanoparticlessupportedonmultiwallcarbonnanotubes(MWCNTs)withoutFeandmultiwallcarbonnanotubeswithiron(MWCNTs-Fe)whichappliedaselectrocatalystsformethanolelectrooxidation.APtcoordinationcomplexsaltwassynthesizedinanaqueoussolutionanditwasusedasprecursortopreparePt/MWCNTs,Pt/MWCNTs-Fe,andPt-Fe/MWCNTsusingFeCl24H2OasironsourcewhichwerenamedS1,S2andS3,respectively.Thecoordinationcomplexofplatinum(TOA)2PtCl6wasobtainedbythechemicalreactionbetween(NH4)2PtCl6withtetraoctylammoniumbromide(TOAB)anditwascharacterizedbyFT-IRandTGA.ThematerialswerecharacterizedbyRamanspectroscopy,SEM,EDS,XRD,TEMandTGA.TheelectrocatalyticactivityofPt-basedsupportedonMWCNTsinthemethanoloxidationwasinvestigatedbycyclicvoltammetry(CV)andchronoamperometry(CA).Pt-Fe/MWCNTselectrocatalystsshowedthehighestelectrocatalyticactivityandstabilityamongthetestedelectrocatalystsduetothattheadditionof'Fe'promotestheOHspeciesadsorptionontheelectrocatalystsurfaceatlowpotentials,thus,enhancingtheactivitytowardthemethanoloxidationreaction(MOR).

简介：TwospeciesofN-arylpyrazolescontainingactiveaminogroupweresynthesized.AndformylationsofN-arylpyazolescontainingaminoindifferentpositionofpyrazoleringsusingVilsmeier-Haackreactiongaveaseriesofusefulpyrazoleintermediates.Theimportantfeaturesofthisprotocolwerecheapmaterials,easyprocess,mildreactionconditionsandgoodyieldofproducts.

简介：ThemechanismoftheinterfacialreactionofAl2O3/mediumMnsteelcontainingNbwasstudiedbymeansoftheobservationontheinterfacialreactionphenomenonofAl2O3/mediumMnsteel,andtheanalysesontheinterracialphases.TheresultsshowthatwhenT≥1550℃,theinterfacialreac-tionofAl2O3/mediumMnsteelcontainingNbhappened.InthemediumMnsteelmatrix,NbexistsintheformofNbC.NbCarethenucleatingbaseofCOgasbubbles.

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