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500 个结果
  • 简介:Akineticequationofnon-isothermalcrystamzationwasderivedbyextendingAvrami’sequationtothenon-isothermalsituation.Morecrystallizationinformationcanbeobtainedfromthiskineticequation.Thecurvesofnon-isothermalandisothermalcrystallizationswereanalysedandcomparedforpoly(ethyleneterephthalate)(PET),andtheresultswerediscussed.

  • 标签: NON-ISOTHERMAL CRYSTALLIZATION CRYSTALLIZATION KINETICS Poly (ethyene
  • 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.

  • 标签: 非等温结晶动力学 多壁碳纳米管 纳米复合材料 聚酰胺 Avrami方程 差示扫描量热法
  • 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.

  • 标签: PYROLYSIS BEHAVIOR KINETIC analysis TG/DTG CURVES
  • 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.

  • 标签: VANADIUM NITRIDE REDUCTION and NITRIDATION Thermog
  • 简介:在花的催化裂开的催化剂上扔的焦炭的氧化经由非等温的氧化工具与煤和煤字符的相比,即thermal-gravimetric分析(TGA)和微分热分析(DTA)。氧化运动参数被模型试穿方法进一步调查。测试结果证明花的催化剂的氧化是一个相当温和的过程,当煤和煤字符在氧化期间经历了锋利的重量损失时。为氧化的开始和结束的温度在下列顺序增加了:煤

  • 标签: 催化裂解催化剂 非等温氧化 废催化剂 煤氧化 反应动力学参数 反应模型
  • 简介:Thenon-isothermalleachingkineticsofprimarytitanium-richmaterialbymicrowaveheatingwasinvestigated,andthetemperature-pressurecurvesofleachingsystemandmicrowaveabsorptioncharacteristicsofmixturesolutionsbeforeandafterleachingweremeasured.Theresearchofnon-isothermalkineticswasevaluatedbytheleachingrateofFeandthetotalapparentvelocityequationofthenon-isothermalkineticsofleachingforprimarytitanium-richmaterialbymicrowaveheatingwasobtained.Itisshownfromthetemperature-pressurecurvesthatthehightemperatureandhighpressureofclosedleachingsystemarefavorabletotheenhancementoftheleachingrateofFe.Microwaveabsorptioncharacteristicsofmixturesolutionsbeforeandafterleachingshowthatthereareabruptchangesofmicrowaveabsorptioncharacteristicsfor15%HClsolutionandthemixturesolutionafterleachingby20%HCl.

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  • 简介:作者主要学习追踪算法到稳定的Euler系统和等温的Euler系统的波浪前面产生的弱答案的差别。在起始的数据足够地具有的假设下面小全部的变化,稳定的Euler系统和等温的超声的流动的系统的解决方案之间的差别能被起始的不安的全部的变化的立方体围住,这被证明。

  • 标签: 稳定系统 欧拉 等温 2维 逼近 跟踪算法
  • 简介:ThestructureofaggregationstateandisothermalcrystallizationbehaviorofNylon-1010havebeenstudiedbyWAXD,DSE,Variance-RangeFunctionanddensitymeasurement.TheresultsshowthatcrystallizationofNylon-1010hasthemostsuitableannealingtemperature,thecrystalsoftheNxlon-1010aretwo-dimensionheterogeneousnucleation.Bothlowtreatmenttemperatureandhighcrystallizationte,temperaturearedisadvantageousforNylon-1010crystalgrowth.

  • 标签: ANNEALING NYLON NUCLEATION AGGREGATION ISOTHERMAL WAXD
  • 简介:A2m~3isothermalcloudchambermainlyforicenucleationresearchisdescribedinthispaper.Itsstructure,attachedinstrumentsandexperimentalproceduresarealsopresented.TheexperimentsofdeterminingtheicenucleieffectivenessfortheAgl-containingaerosolsproducedbythreeformulationshavebeenconductedandtheresultshavebeencomparedwiththoseoftheCSU960-literisothermalcloudchamber.Allexperimentalresultsshowthatthechamberhasadvantagesofstableperformanceandreproducibility.Itwouldbeexpectedtobecomeausefulexperimentalfacilityforicenucleationresearch.

  • 标签: NUCLEATION ISOTHERMAL instruments cloud ATTACHED AEROSOLS
  • 简介:同时的免费传送对流在上面并且在一个一致地激烈的水平盘子下面广泛地被调查了在等温的表面的情况中,并且一致地激烈的表面,但是总是作为液体(Pr=0.7)假定仅仅空气。不过,有工作,处理其结果证明Pr上的Nu依赖不能被一条幂定律简单地与Gr那的一样的代表表示的水平盘子。在等温的水平长带的情况中学习Prandtl数字影响因此被认为有用。,结果为长带的更低的表面显示出那在Gr的Nu依赖能被一条幂定律与代表结束表示到Gr那,为代表是的上面的表面聪明地不同。与调查状况有关的相关方程被建议。

  • 标签: 普朗特数 自由对流 传热 公约 薄带 卧式
  • 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.

  • 标签: Fatty liver Non-alcoholic fatty liver disease Non-alcoholic steatohepatitis Liver fibrosis Cirrhosis Transient elastography FibroScan Magnetic resonance imaging
  • 简介:Thispaperinvestigatesthemathematicfeaturesofnon-linearmodelsanddiscussestheprocessingwayofnon-linearfactorswhichcontributestothenon-linearityofanonlinearmodel.Onthebasisoftheerrordefinition,thispaperputsforwardanewadjustmentcriterion,SGPE.Last,thispaperinvestigatesthesolutionofanon-linearregressionmodelinthenon-linearmodelspaceandmakesthecomparisonbetweentheestimatedvaluesinnon-linearmodelspaceandthoseinlinearmodelspace.

  • 标签: 非线性调节模型 测量误差 精确度 空间非线性模型
  • 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。

  • 标签: 均匀化处理 等温时效 钆合金 力学性能 显微组织 时效处理
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  • 简介:Anumericalanalysisofnon-Newtonianfluidflowinnon-planararterywithbifurcationwasperformedbyusingafiniteelementmethodtosolvethethree-dimensionalNavier-Stokesequationscoupledwiththenon-Newtonianconstitutivemodels,includingCarreau,CrossandBinghammodels.Theobjectiveofthisstudyistoinvestigatetheeffectsofthenon-Newtonianpropertiesofbloodaswellascurvatureandout-of-planegeometryinthenon-planardaughtervesselsonthevelocitydistributionandwallshearstress.Theresultsofthisstudysupporttheviewthatthenon-planarityofbloodvesselsandthenon-Newtonianpropertiesofbloodareofimportantinhemodynamicsandplayasignificantroleinvascularbiologyandpathophysiology.

  • 标签: 非线性牛顿流体 血液动力学 颈动脉分流 数值分析 非平面动脉 病理生理学
  • 简介:Bacterialflagellarfilamentcanundergoastress-inducedpolymorphicphasetransitioninbothvitroandvivoenvironments.Thefilamenthas12differenthelicalforms(phases)characterizedbydifferentpitchlengthsandhelixradii.Whensubjectedtothefrictionalforceofflowingfluid,thefilamentchangesbetweenaleft-handednormalphaseandaright-handedsemi-coiledphaseviaphasenucleationandgrowth.Thispaperdevelopsnon-localfiniteelementmethod(FEM)tosimulatethephasetransitionunderad...

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  • 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.

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  • 简介:SeveralextensionsofthelogicprogramminglanguagePrologtononHornclausesusecaseanalysistohandlenon-Hornclauses.Inthispaper,analyticalandempriricalevidencesarepresentedtoshowthat,bymakingasetofclausesless'non-Horn'usingpredicatedrenaming.theperformanceofthesecase-analysisbasedprocedurescanbeimprovedsignificantly.Inaddition,thepaperalsoinvestigatedtheproblemofefficeientlyconstructingapredicaterenamingthatreducesthedegreeof'non-Hornness'ofaclausesetmaximally.Itisshownthatthisproblemoffindingaredicaterenamingtoachieveminimal'non-Hornness'isNP-complete.

  • 标签: 人工智能 逻辑程序设计 NP-完备性