简介：ThecorrelationbetweenphasestructuresandsurfaceacidityofAl2O3supportscalcinedatdifferenttemperaturesandthecatalyticperformanceofNi/Al2O3catalystsintheproductionofsyntheticnaturalgas(SNG)viaCOmethanationwassystematicallyinvestigated.Aseriesof10wt%NiO/Al2O3catalystswerepreparedbytheconventionalimpregnationmethod,andthephasestructuresandsurfaceacidityofAl2O3supportswereadjustedbycalciningthecommercialγ-Al2O3atdifferenttemperatures(600–1200C).COmethanationreactionwascarriedoutinthetemperaturerangeof300–600Catdifferentweighthourlyspacevelocities(WHSV=30000and120000mL·g-1h-1)andpressures(0.1and3.0MPa).ItwasfoundthathighcalcinationtemperaturenotonlyledtothegrowthinNiparticlesize,butalsoweakenedtheinteractionbetweenNinanoparticlesandAl2O3supportsduetotherapiddecreaseofthespecificsurfaceareaandacidityofAl2O3supports.Interestingly,NicatalystssupportedonAl2O3calcinedat1200C(Ni/Al2O3-1200)exhibitedthebestcatalyticactivityforCOmethanationunderdifferentreactionconditions.LifetimereactiontestsalsoindicatedthatNi/Al2O3-1200wasthemostactiveandstablecatalystcomparedwiththeotherthreecatalysts,whosesupportswerecalcinedatlowertemperatures(600,800and1000C).ThesefindingswouldthereforebehelpfultodevelopNi/Al2O3methanationcatalystforSNGproduction.

简介：物业管理招投标的那些事“8844号专家，请于2013年1月16日13时30分前到设计大厦三楼评标，能出席回复11，不能出席回复10，详询83785991”。1月16日12时28分，深圳某物业评标专家收到市建设工程交易服务中心的邀请评标短信，去电一问，原来必须在10分钟内回复短信，如在第二轮被抽中，还必须在上述时间内赶到现场……一阵手忙脚乱地回复短信后，却因超时被回复“逾期作废”。

简介：IncorporationofstrontiumintoV-Moalumina-supportedcatalystenhanceditsperformance(increasedconversionandselectivity,decreasedreducibilityandimprovedstability)inpropaneoxydehydrogenationtopropylene.12.5%SrloadingwasshowntobetheoptimumcontenttotheV-Mocatalyst.Theresultsweresupportedbyvariouscharacterizationtechniques,namely,BET,XRD,SEM,FTIRandTPD.

简介：

简介：空气中的S0-2气体对丝织品文物有一定的危害作用。课题分别试验了各种丝织品试样在50μmol／mol的SO2气体下不同时间的影响变化。通过色差分析，红外分析，氨基酸分析及XRD分析对丝织品进行表征，得到了40℃下50天的干热老化丝织品试样在50μmol／mol的S0-2气体下，随着试验时间的延长，其色差变化最大。经S02气体处理的丝织品试样的氨基酸成分发生改变，结晶度也变大，老化程度加大。本研究结果可为保存和保护丝织品文物提供依据。

简介：Calciumhexaluminate(CA6)wassynthesizedbymixinglight-weightcalciumcarbonateandAl2O3micropowder(calcinedα-Al2O3,activatedα-Al2O3orρ-Al2O3)accordingtothestoichimetricratioofCA6,andreactionsinteringat1200,1300,1400and1500℃for3h,respectively.Effectsofthethreealuminamicropowdersonthephasecomposition,microstructureandpropertiesofCA6wereinvestigated.Theresultsshowthat:(1)forthethreeAl2O3micropowders,thereactiontogenerateCA6inspecimensbasicallycompletesatabout1500℃;CA6generatedinallspecimensisplanar,butthearraymodesareslightlydifferent;(2)thespecimenspreparedfromcalcinedα-Al2O3orρ-Al2O3shrinkalmost,whilethespecimenspreparedfromactivatedα-Al2O3expand;(3)thecoldcrushingstrengthofthespecimenpreparedfromactivatedα-Al2O3isthehighest,reaching42.5MPawhenonlyCA6exists(afterfiringat1500℃);(4)thespecimenpreparedfromρ-Al2O3hasthelowestgenerationtemperatureofCA6andthehighestapparentporosity,reaching70.1%whenonlyCA6exists(afterfiringat1500℃);(5)thespecimenpreparedfromcalcinedα-Al2O3hasthebiggestbulkdensity.

简介：

简介：Propofolcaninhibittheinflammatoryresponseandreducethesecretionandharmfuleffectsofastrocyte-derivedproinflammatorycytokines.Inthisstudy,afterpropofolwasinjectedintotheinjuredsciaticnerveofmice,nuclearfactorkappaBexpressionintheL4-6segmentsofthespinalcordintheinjuredsidewasreduced,apoptosiswasdecreased,nervemyelindefectswerealleviated,andthenerveconductionblockwaslessened.Theexperimentalfindingsindicatethatpropofolinhibitstheinflammatoryandimmuneresponses,decreasestheexpressionofnuclearfactorkappaB,andreducesapoptosis.Theseeffectsofpropofolpromoteregenerationfollowingsciaticnerveinjury.

简介：

简介：Irradiationfromdiversesourcesisubiquitousandcloselyassociatedwithhumanactivities.Radiationtherapy(RT),animportantcomponentofmultipleradiationorigins,isacommontherapeuticmodalityforcancer.Moreimportantly,RTprovidessignificantcontributiontooncotherapybykillingtumorcells.However,duringthecourseoftherapy,irradiationofnormaltissuescanresultinawiderangeofsideeffects,includingself-limitedacutetoxicities,mildchronicsymptoms,orsevereorgandysfunction.Althoughnumerouspromisingradioprotectiveagentshaveemerged,onlyafewhavesuccessfullyenteredthemarketbecauseofvariouslimitations.Atpresent,thewidelyacceptedhypothesisforprotectionagainstradiation-causedinjuryinvolvestheWntcanonicalpathway.ActivatingtheWnt/β-cateninsignalingpathwaymayprotectthesalivarygland,oralmucosa,andgastrointestinalepitheliumfromradiationdamage.Theunderlyingmechanismsincludeinhibitingapoptosisandpreservingnormaltissuefunctions.However,aberrantWntsignalingunderliesawiderangeofpathologiesinhumans,anditsvariouscomponentscontributetocancer.Moreover,studieshavesuggestedthatWnt/β-cateninsignalingmayleadtoradioresistanceofcancerstemcell.ThesefactsmarkedlycomplicateanydefinitionoftheexactfunctionoftheWntpathway.

简介：

简介：

简介：

简介：

简介：Themutualradiationimpedanceignoredinconventionalarraydirectivityformulaisintroducedintothecalculationofarrayradiationsoundfield,andamodifiedarraydirectivityformulaconsideringthemutualradiationimpedanceisgainedaccordingtothesuperpositionprinciple.Resultsofcomputersimulationandexperimentsforauniformlineararrayandauniformplanararrayshowsuperiorperformanceonthepresentofthepracticaldirectivitypatternofthemodifiedformulainthispaperincomparisontotheconventionalone.

简介：

简介：Theprocessofhighpowerlaserinteractionwiththelargescalelengthcoronaplasmaproducedbytheleadingedgeofthelaserpulsehasbeeninvestigated.Earlyexperimentalresultsarere-analyzedandconclusionsdrawn.Inparticular,studiesofthecloseconnectionofunstablefilamentationinstabilitywith–mainly–two-plasmondecayand–partly–stimulatedRamanscattering,stimulatedBrillouinscattering,andresonanceabsorptionarecarriedoutinthispaper.Thepositiveandnegativeeffectsoffilamentationinstabilityarealsodiscussed.

简介：

简介：Sincerateefectofmaterialsplaysakeyroleinimpactengineering,themicroscopicmechanismofrateeffectisinvestigatedatmolecularlevelinthispaper.Theresultsshowthatrateefectonthestrengthofatomicsystemiscloselyrelatedtothecoupledevolutionofatomicmotionsandpotentiallandscapes.Accordingly,itbecomespossibletodevelopanewalgorithmofmolecularsimulation,whichcouldproperlyandefcientlydemonstratestrainrateefectunderawiderangeofloadingratesandunveilthemechanismsunderlyingthestrainrateefects.

简介：