简介:Akineticequationofnon-isothermalcrystamzationwasderivedbyextendingAvrami’sequationtothenon-isothermalsituation.Morecrystallizationinformationcanbeobtainedfromthiskineticequation.Thecurvesofnon-isothermalandisothermalcrystallizationswereanalysedandcomparedforpoly(ethyleneterephthalate)(PET),andtheresultswerediscussed.
简介:Thenon-isothermalcrystallizationkineticsofpolyamide6/diamine-modifiedmulti-walledcarbonnanotube(PA6/D-MWNT)nanocompositewasinvestigatedbydifferentialscanningcalorimetry(DSC).ThemodifiedAvramiequation,theOzawaequationandthecombinedAvrami/Ozawaequationwereemployedtoanalyzethenon-isothermalcrystallizationdata.ThecrystallizationactivationenergieswerealsoevaluatedbytheKissingermethod.ItwasfoundthatthecombinedAvrami/Ozawaequationcouldsuccessfullydescribethenon-isothermalcrystallizationprocess.TheresultsshowedthatD-MWNTsnotonlyactedaseffectivehetero-geneousnucleatingagentsforPA6andnoticeablyincreasedthecrystallizationtemperatureofPA6,butalsoinfluencedthemechanismofnucleationandcrystalgrowthofPA6andthenreducedtheoverallcrystallizationrateoftheneatPA6matrix.ThecrystallizationactivationenergyforthenanocompositesamplewasgreaterthanthatoftheneatPA6,whichindicatedthattheadditionofD-MWNTshinderedthemobilityofPA6chainsegments.
简介:Investigationsonthepyrolysisandkineticbehaviorsduringpyrolysisoffossilfuelsamples,suchascoal,arefundamentalfordevelopingtherelatedtechnologyandpracticalapplication.Inthiswork,pyrolysisbehaviorandkineticsinthepyrolysisprocessofacoalsamplewereinvestigatedbythethermogravimetricanalyzerataheatingrateof10,40,70,100,200,and500°C/min,respectively.ThepyrolysisprocesscouldbedividedintofourstagesaccordingtotheTG/DTGcurves.Thefirststagewasmainlyattributedtotheremovalofvolatiles,andthesecondpeakwasthepolycondensationreactionbetweenthevolatilecomponents.Itwasfoundthatmorevolatilescouldbereleasedfromcoalduringpyrolysisathigherheatingrateandthehigherpyrolysistemperaturewasnecessaryforarapidpyrolysisprocess.Kineticanalysisrevealedthatboththemodel-free(KASandFWO)andtheCoats-Redfernmethodsweresuitabletodescribingthepyrolysisprocess,andthevariationofactivationenergy(E)withthetwotypesofkineticmodelswasconsistentduringthewholepyrolysisprocess.Furthermore,theheatingratedidnotalterthereactionsequenceofthewholepyrolysisprocess,buthigherheatingratecouldmaketheEvalueoftheinitialpyrolysisstagesmaller.
简介:Vanadiumnitridewassynthesizedbyone-stepmethodusingV2O5andcarbonblackasrawmaterialsinnitrogenatmosphere.ThephasesofdifferentreactionproductspreparedindifferentreactiontemperatureswereanalyzedbyX-raydiffraction(XRD),andthedynamicbehavioroftheprocessofsynthesizingvanadiumnitride(VN)byone-stepmethodwasstudiedwithnon-isothermalthermogravimetry.Themechanismfunctionandkineticparametersofreactionprocesswerecalculatedbythermalgravimetricanalyses(TGA),andthereactionrateequationwasestablished.TheXRDresultsshowthatforthesamplestestedwithminimalVNafterholdingfor4hat1273K,themainphaseofproductsisVNat1476K,whilesomevanadiumnitridestransformintovanadiumcarbidesagainover1573K.ItisfoundthatN2isbeneficialtostimulatereductionandproceedcarbonizationreaction,andthereductionandnitridationreactioncanoccursimultaneously.TheactivationenergyofpreparingVNbyone-stepmethodis104.005kJ·mol-1,andthefrequencyfactoris470.52at1280–1358K,and150.052kJ·mol-1and2.359104at1358–1426K,respectively.
简介:Thenon-isothermalleachingkineticsofprimarytitanium-richmaterialbymicrowaveheatingwasinvestigated,andthetemperature-pressurecurvesofleachingsystemandmicrowaveabsorptioncharacteristicsofmixturesolutionsbeforeandafterleachingweremeasured.Theresearchofnon-isothermalkineticswasevaluatedbytheleachingrateofFeandthetotalapparentvelocityequationofthenon-isothermalkineticsofleachingforprimarytitanium-richmaterialbymicrowaveheatingwasobtained.Itisshownfromthetemperature-pressurecurvesthatthehightemperatureandhighpressureofclosedleachingsystemarefavorabletotheenhancementoftheleachingrateofFe.Microwaveabsorptioncharacteristicsofmixturesolutionsbeforeandafterleachingshowthatthereareabruptchangesofmicrowaveabsorptioncharacteristicsfor15%HClsolutionandthemixturesolutionafterleachingby20%HCl.
简介:ThestructureofaggregationstateandisothermalcrystallizationbehaviorofNylon-1010havebeenstudiedbyWAXD,DSE,Variance-RangeFunctionanddensitymeasurement.TheresultsshowthatcrystallizationofNylon-1010hasthemostsuitableannealingtemperature,thecrystalsoftheNxlon-1010aretwo-dimensionheterogeneousnucleation.Bothlowtreatmenttemperatureandhighcrystallizationte,temperaturearedisadvantageousforNylon-1010crystalgrowth.
简介:A2m~3isothermalcloudchambermainlyforicenucleationresearchisdescribedinthispaper.Itsstructure,attachedinstrumentsandexperimentalproceduresarealsopresented.TheexperimentsofdeterminingtheicenucleieffectivenessfortheAgl-containingaerosolsproducedbythreeformulationshavebeenconductedandtheresultshavebeencomparedwiththoseoftheCSU960-literisothermalcloudchamber.Allexperimentalresultsshowthatthechamberhasadvantagesofstableperformanceandreproducibility.Itwouldbeexpectedtobecomeausefulexperimentalfacilityforicenucleationresearch.
简介:AbstractFor the detection of steatosis, quantitative ultrasound imaging techniques have achieved great progress in past years. Magnetic resonance imaging proton density fat fraction is currently the most accurate test to detect hepatic steatosis. Some blood biomarkers correlate with non-alcoholic steatohepatitis, but the accuracy is modest. Regarding liver fibrosis, liver stiffness measurement by transient elastography (TE) has high accuracy and is widely used across the world. Magnetic resonance elastography is marginally better than TE but is limited by its cost and availability. Several blood biomarkers of fibrosis have been used in clinical trials and hold promise for selecting patients for treatment and monitoring treatment response. This article reviews new developments in the non-invasive assessment of non-alcoholic fatty liver disease (NAFLD). Accumulating evidence suggests that various non-invasive tests can be used to diagnose NAFLD, assess its severity, and predict the prognosis. Further studies are needed to determine the role of the tests as monitoring tools. We cannot overemphasize the importance of context in selecting appropriate tests.
简介:Thispaperinvestigatesthemathematicfeaturesofnon-linearmodelsanddiscussestheprocessingwayofnon-linearfactorswhichcontributestothenon-linearityofanonlinearmodel.Onthebasisoftheerrordefinition,thispaperputsforwardanewadjustmentcriterion,SGPE.Last,thispaperinvestigatesthesolutionofanon-linearregressionmodelinthenon-linearmodelspaceandmakesthecomparisonbetweentheestimatedvaluesinnon-linearmodelspaceandthoseinlinearmodelspace.
简介:Mg-12Gd-2Er-1Zn-0.6Zr(wt%)合金的机械性质上的homogenization和等温的老化处理的效果被调查。猛抛的长时期的叠顺序(LPSO)结构和调节合金的变老的降水顺序分别地被观察并且分析。结果显示14H-LPSO结构在等温的老化过程以后发生在homogenization处理和阶段形式以后。这二个独立过程能被降水温度范围控制。在homogenization处理以后的当演员组合金的延伸的重要增加被归因于粗糙的主要Mg5(Gd,的消失嗯,Zn)阶段和14H-LPSO结构的存在。调查合金的降水顺序是-Mg(SSS)/(D019)/(cbco)/。而且,张力的力量(YTS)和最终的张力的力量(UTS)等温的老化合金珍视的收益有大改进,它能被归因于猛抛的阶段的高密度。图形的AbstractWith延长的变老的时间,阶段在合金被猛抛。14H-LPSO结构和阶段在498K为84h在老化以后在合金共存。14H-LPSO的层结构显然被观察[11\(\overline{2}\)0]Mg方向,它在高分辨率的传播电子显微镜学(HRTEM)被显示出图象。14H类型结构与c的一个时期显示一份叠的订单?=?3.67?nm,它不在等温的老化过程期间变化。
简介:Anumericalanalysisofnon-Newtonianfluidflowinnon-planararterywithbifurcationwasperformedbyusingafiniteelementmethodtosolvethethree-dimensionalNavier-Stokesequationscoupledwiththenon-Newtonianconstitutivemodels,includingCarreau,CrossandBinghammodels.Theobjectiveofthisstudyistoinvestigatetheeffectsofthenon-Newtonianpropertiesofbloodaswellascurvatureandout-of-planegeometryinthenon-planardaughtervesselsonthevelocitydistributionandwallshearstress.Theresultsofthisstudysupporttheviewthatthenon-planarityofbloodvesselsandthenon-Newtonianpropertiesofbloodareofimportantinhemodynamicsandplayasignificantroleinvascularbiologyandpathophysiology.
简介:Bacterialflagellarfilamentcanundergoastress-inducedpolymorphicphasetransitioninbothvitroandvivoenvironments.Thefilamenthas12differenthelicalforms(phases)characterizedbydifferentpitchlengthsandhelixradii.Whensubjectedtothefrictionalforceofflowingfluid,thefilamentchangesbetweenaleft-handednormalphaseandaright-handedsemi-coiledphaseviaphasenucleationandgrowth.Thispaperdevelopsnon-localfiniteelementmethod(FEM)tosimulatethephasetransitionunderad...
简介:TheCu/Sn-3.OAg-0.5Cu/Cubuttingsolderjointswerefabricatedtoinvestigatetheevolutionoftheinterfacialintermetalliccompound(IMC)andthedegradationofthetensilestrengthofsolderjointsundertheeffectofelectromigration(EM)andagingprocesses.Scanningelectronmicroscopy(SEM)resultsindicatedthattheCu_6Sn_5interfacialIMCpresentedobviousasymmetricalgrowthwiththeincreaseofEMtimeundercurrentdensityof1.78×10~4A/cm~2at100℃,andthegrowthofanodicIMCpresentedaparabolicrelationshipwithtimewhilethecathodicIMCgotthinnergradually.However,asforagingsamplesat100℃withoutcurrentstressing,theCu_6Sn_5IMCpresentedasymmetricalgrowthwithaslowerratethantheanodicIMCofEMsamples.Thetensileresultsindicatedthatthetensilestrengthofthesolderjointsundercurrentstressdeclinedmoredrasticwithtimethantheagingsamples,andthefracturemodetransformedfromductilefracturetobrittlefracturequicklywhilethefracturemodeofagingsamplestransformedfromcup-coneshapedfracturetomicroporousgatheringfractureinaslowway.
简介:SeveralextensionsofthelogicprogramminglanguagePrologtononHornclausesusecaseanalysistohandlenon-Hornclauses.Inthispaper,analyticalandempriricalevidencesarepresentedtoshowthat,bymakingasetofclausesless'non-Horn'usingpredicatedrenaming.theperformanceofthesecase-analysisbasedprocedurescanbeimprovedsignificantly.Inaddition,thepaperalsoinvestigatedtheproblemofefficeientlyconstructingapredicaterenamingthatreducesthedegreeof'non-Hornness'ofaclausesetmaximally.Itisshownthatthisproblemoffindingaredicaterenamingtoachieveminimal'non-Hornness'isNP-complete.