学科分类
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59 个结果
  • 简介:Laminatedcompositematerialsarewidelyimplementedinseveralengineeringconstructions.Foritsrelativelightweight,thesematerialsaresuitableforaerospace,military,marine,andautomotivestructuralapplications.Toobtainsafeandeconomicalstructures,themodellinganalysisaccuracyishighlyrelevant.Sincemeshlessmethodsintherecentyearsachievedaremarkableprogressincomputationalmechanics,thepresentworkusesoneofthemostflexibleandstableinterpolationmeshlesstechniqueavailableintheliterature—theRadialPointInterpolationMethod(RPIM).Here,a2Dapproachisconsideredtonumericallyanalysecompositelaminatedbeams.Boththemeshlessformulationandtheequilibriumequationsrulingthestudiedphysicalphenomenonarepresentedwithdetail.Severalbenchmarkbeamexamplesarestudiedandtheresultsarecomparedwithexactsolutionsavailableintheliteratureandtheresultsobtainedfromacommercialfiniteelementsoftware.Theresultsshowtheefficiencyandaccuracyoftheproposednumerictechnique.

  • 标签: RADIAL POINT interpolators RPIM LAMINATED BEAM
  • 简介:在组成的部件之间的有瑕疵的结合能极大地影响合成结构的性质。处于2Dfibrereinforced的问题产生的有瑕疵的接口的不同类型的asymptotic分析合成材料被建议。执行学习基于管理biharmonic问题的asymptotic减小进二个泛音问题。所有答案在一种关上的分析形式被获得。获得的结果能被用于撤退和pushout测试的计算,以及为合成材料的破裂的调查。

  • 标签: 复合材料界面 纤维增强 2D 复合材料结构 双调和问题 组成成分
  • 简介:ThecaptureoforthophosphatesandtotalphosphorusfromthePudongCanalriverinthePudongDistrictofShanghaibyTiO2nanoparticlesisstudiedusingarotatingphotoreactorandthenano-TiO2photocatalystDegussaP25.TheeffectsofUVirradiationintensityinarangeof20-74mW/cm2.theloadingoftheTiO2nanoparticlesinarangeof0.05-0.1g/L,irradiationtimeupto4h,andpHvaluesinarangeof2-10.5onthecaptureefficiencyareinvestigated.TheresultsshowthatthecaptureoforthophosphatesandtotalParesignificantlyenhancedbyUVirradiation;ataloadingof0.1g/Landanirradiationintensityabove36mW/cm2,orthophosphatesandtotalphosphorusarerapidlycapturedbyTiO2nanoparticles,causinganobservedreductionfrom0.4mg/Ldownto0.02mg/L.pHvaluesinarangeof2-10.5havelittleeffectonthecaptureefficiencyoforthophosphatesandtotalphosphorus.

  • 标签: 纳米二氧化钛光催化剂 紫外光照射 捕获 总磷 二氧化钛纳米粒子 地表水
  • 简介:Hierarchicalsea-urchin-shapedmanganeseoxidemicrospheresweresynthesizedviaatacilemetnoabasedonthereactionbetweenKMnO4andMnSO4inHNO3solutionat50C.Theaveragediameterofthemicrospheresis850nm.Themicrospheresconsistofacoreofdiameterof800nmandnanorodsofwidth50nm.Thenanorodsexistattheedgeofthecore.TheBrunauer-Emmett-Tellersurfaceareaofthesea-urchin-shapedmicrospheresis259.4m2/g.Apossibleformationmechanismofthehierarchicalsea-urchin-shapedmicrospheresisproposed.Thetemperaturefor90%conversionofbenzene(T90%)onthehierarchicalurchin-shapedMnO2microspheresisabout218℃.

  • 标签: 催化氧化 MNO2 型综合 平均直径 二氧化锰
  • 简介:ZrO2nanopowdersbasedstearicacidphasechangematerials(PCMs)werepreparedbyhigh-energymilling.Theconceptofheatcapacityfactor(HCF)wasusedtoanalyzethethermalpropertiesofthematerials.TheheatstoragepropertyofPCMs,containingthesamecontentofstearicacid(23%bymass)inthestartingmaterialsbutsynthesizedbydifferenttechnicalprocesses,wasinvestigatedbyusingHCF.Itwasfoundthattherewerevastinfluencesofdifferentdispersantsontheheatcapacity.Thesamplespreparedwithchloroformprovidedthebestheatstorageabilityinallsamplestested.

  • 标签: 相变材料 纳米粉体 硬脂酸 氧化锆 基础研究 蓄热性能
  • 简介:Anewmicromechanicsconstitutivemodelforpuredilatanttransformationplasticityofstructureceramicsisproposedinthispaper.Basedonthethermodynamics,micromechanicsandmicroscalet→mtrans-formationmechanismanalysisoftheTZPandPSZZrO2-containingceramics,ananalyticexpressionsoftheHelmholtzandcomplementaryfreeenergyoftheconstitutiveelementforthecaseofpuredilatanttransforma-tionisderivedforthefirsttimeinaself-consistentmanner.Bytheanalysisofenergydissipationinthefor-wardandreversetransformations,themieromechanicsconstitutivelawisderivedintheframeworkofHill-Rice’sinternalvariableconstitutivetheory.

  • 标签: CONSTITUTIVE element microscopic and MACROSCOPIC quantities
  • 简介:Afacilemethodforthesynthesisofsilver-silica(Ag-SiO2)Janusparticleswithfunctionalitiessuitablefortextileapplicationsisreported.SilicananoparticlespreparedbytheStobermethodwerefunctionalizedwithepoxy,amine,andthiolgroups,whichwereconfirmedbyFouriertransforminfraredanalysis.ThefunctionalizedsilicananoparticleswereusedtoproducePickeringemulsions,andtheexposedsurfacewasusedfortheattachmentofsilvernanoparticles(AgNPs)viathelow-temperaturechemicalreductionmethod.ThemorphologyandstructureoftheAg-SiO2Janusparticleswerecharacterizedbyscanningelectronmicroscopy,scanningtransmissionelectronmicroscopy,high-resolutiontransmissionelectronmicroscopy,energy-dispersiveX-rayanalysis,andUV-visspectroscopy.Becauseoftheirspecificfunctionalities,theseAg-SiO2Janusparticlesareproposedforapplicationsontextilesubstrates,astheycanovercomeseveraldrawbacksofdirectapplicationofAgNPsontextiles,suchasleaching,agglomeration,andinstabilityduringstorage.

  • 标签: 硅纳米颗粒 纺织应用 原位合成 环氧树脂 纺织品 二氧化硅纳米粒子
  • 简介:Thispaperpresentsanovelmechanicalattachment,i.e.,nonlinearenergysink(NES),forsuppressingthelimitcycleoscillation(LCO)ofanairfoil.Thedynamicresponsesofatwo-degree-of-freedom(2-DOF)airfoilcoupledwithanNESarestudiedwiththeharmonicbalancemethod.DiferentstructureparametersoftheNES,i.e.,massratiobetweentheNESandairfoil,NESofset,NESdamping,andnonlinearstifnessintheNES,arechosenforstudyingtheefectoftheLCOsuppressiononanaeroelasticsystemwithasupercriticalHopfbifurcationorsubcriticalHopfbifurcation,respectively.TheresultsshowthatthestructuralparametersoftheNEShavediferentinfluenceonthesupercriticalHopfbifurcationsystemandthesubcriticalHopfbifurcationsystem.

  • 标签: 非线性能 2自由度 振荡抑制 极限周期 机翼 量水槽
  • 简介:为它的高氧化抵抗,钇硅酸盐是为在在1600°C上面的温度的carbon-fiber-reinforcedcomposites的保护的涂层的一个重要候选人。一个新奇方法,由一起沉淀组成,弄干水花,热处理和plasma-densification,被开发准备Y2SiO5粉末为热喷洒。作文,形态学和综合Y2SiO5粉末的流动能力被XRD,SEM和霍尔流量计分别地调查。结果证明综合Y2SiO5粉末与高纯净是将近球形的。分别地,Y2SiO5粉末的明显的密度和流动能力是1.87g/cm3和37s/50g它为大气的血浆喷洒导致多达80%的高免职效率。

  • 标签: Y2SIO5 粉末流动 热喷涂 球形 大气等离子喷涂 制备
  • 简介:Aunifiedperturbationtheoryisdevelopedhereforcalculatingsolitarywavesofallheightsbyseriesexpansionofbaseflowvariablesinpowersofasmallbaseparametertoeighteenthorderfortheone-parameterfamilyofsolutionsinexactform,withallthecoefficientsdeterminedinrationalnumbers.Comparativestudiesarepursuedtoinvestigatetheeffectsduetochangesofbaseparameterson(i)theaccuracyofthetheoreticallypredictedwavepropertiesand(ii)therateofconvergenceofperturbationexpansion.Twoimportantresultsarefoundbycomparisonsbetweenthetheoreticalpredictionsbasedonasetofparametersseparatelyadoptedforexpansioninturn.First,theaccuracyandtheconvergenceoftheperturbationexpansions,appraisedversustheexactsolutionprovidedbyanearlierpaper[1]asthestandardreference,arefoundtodepend,quitesensitively,onchangesinbaseparameter.Theresultingvariationsinthesolutionarephysicallydisplayedinvariouswavepropertieswithdifferencesfounddependentonwhichproperty(e.g.thewaveamplitude,speed,itsprofile,excessmass,momentum,andenergy),onwhatrangeinvalueofthebase,andontherankoftheordernintheexpansionbeingaddressed.Secondly,regardingconvergence,thepresentperturbationseriesisfounddefinitelyasymptoticinnature,withtherelativeerrorδ(n)(therelativemean-squaredifferencebetweensuccessiveordersnofwaveelevations)reachingaminimum,δm,ataspecificorder,n=nm,bothdependingonthebaseadopted,e.g.n=11-12basedonparameterα(waveamplitude),nm,β=15onβ(amplitude-speedsquareratio),andnm.∈=17on∈(wavenumbersquared).Theasymptoticrangeisbroughttocompletionbythehighestorderofn=18reachedinthiswork.

  • 标签: 孤波 统一混乱理论 高次波 基础函数 渐近表示 力学
  • 简介:Nano-sizedhexagonalmagnesiumhydroxide(Mg(OH)2)withgooddispersibilitywassynthesizedbyadoubleinjection-hydrothermalmethod,utilizingpolyvinylpyrrolidone(PVP)asanadditiveandwithoptimizedprocessingparameters.SEMandBETanalysisshowedthatthemeanparticlesizeandspecificsurfaceareaoftheMg(OH)2particleswere174nmand50.77m2/g,respectively.TheFT-IRspectraandtheXRDpatternsshowedthatPVPwasadsorbedonthesurfaceoftheMg(OH)2crystal,thuseffectivelylimitingparticleagglomerationandhinderingcrystalgrowthalongthe(101)plane.TGAshowedadecreaseinthedecompositiontemperatureandanincreaseintheweightlossoftheMg(OH)2particlesduetoadditionofPVP.

  • 标签: 纳米尺寸 氢氧化镁 六边形 可控制备 MG(OH)2 聚乙烯吡咯烷酮
  • 简介:从理论上推导了声学超表面对平面声波的作用模型,该理论模型计及声波高阶衍射模态,从而能够计及超表面微结构之间的声学干扰.通过与数值结果对比,该模型预测的反射频率精度得到了一定程度的提高,并能够分辨出相邻孔声场之间的耦合模态.讨论了声学超表面吸声特性与阻抗特性对高超声速边界层内Mack第2模态的抑制机理,研究发现通过设计超表面阻抗特性,使得入射声波与反射声波在壁面处相位相反,同样可以抑制Mack第2模态.基于理论模型,分别优化设计得到最优的微结构几何尺寸,并通过对Mach6平板边界层流动进行稳定性分析,验证了超表面不同声学特性的抑制效果.

  • 标签: 声学超表面 Mack第2模态 稳定性分析 高超声速边界层流动 直接数值模拟
  • 简介:W,N共同做TiO2nanoparticles被一个solgel方法综合。准备样品被X光检查衍射(XRD)描绘,域排放扫描电子显微镜学(FE-SEM),传播电子显微镜学(TEM),Fourier变换红外线的光谱学(英尺红外),X光检查光电子光谱学(XPS)和弥漫的反射spectrophotometry(医生)。结果证明共同做的光催化剂是有22.5nm的最小的粒子尺寸的实质上一致的球形的粒子。比作未做的TiO2,N-TiO2和P-25,W的吸收边,N共同做转移到更长的波长的TiO2和它为在Xe灯(350W)下面的甲基橘子(瞬间)的降级的photocatalytic活动更高。

  • 标签: N-TiO2 光催化剂 共掺杂 场发射扫描电子显微镜 光驱动 傅里叶变换红外光谱
  • 简介:从地下的管子的漏能导致被破坏并且引起损坏到邻近的基础结构的基础。包围漏的区域的土壤粒子能从由漏的液体的土壤矩阵被动员,代替,并且甚至洗了,产生虚空或洞。用acoupled的二维的模拟分离元素方法和格子Boltzmann方法(DEMLBM)被用来调查一个土壤床题目的行为到局部地注射的液体,它在一根管子中代表一条漏缝。内部粒子的表面精力的各种各样的价值也被采用为连贯的粒子的机械效果建模。结果建议内部粒子的表面精力极大地关于漏的液体影响床反应,包括开始洞,洞形状和它的进化率的过量压力。

  • 标签: 土壤颗粒 注射液 格子BOLTZMANN方法 行为 二维 管道泄漏
  • 简介:在现在的纸,包含三个任意的函数为的一个一般解决方案概括(2+1)维的KdV-mKdV方程,它被导出从概括(1+1)维的KdV-mKdV方程,首先借助于Wiess被介绍,小鼓,Carnevale(WTC)截断方法。然后有考虑的几条能量守恒定律的multisymplectic明确的表达被介绍为概括(2+1)维的KdV-mKdV方程基于桥的multisymplectic理论。随后,源于以便以Jacobi椭圆形的功能的合理功能模仿周期的波浪答案一般答案,一个半含蓄的multi-symplectic计划被构造那等价于Preissmann计划。从数字实验的结果,我们能断定multi-symplectic计划能精确地模仿周期的波浪答案概括(2+1)维的KdV-mKdV方程当时近似保存能量守恒定律。

  • 标签: KDV-MKDV方程 KDV-MKDV方程 广义 PREISSMANN格式 JACOBI椭圆函数 辛方法
  • 简介:一系列碳nanotubes/TiO2nanotubes(CNTs/TNTs)合成光催化剂被CNT的加入成功地在HNO3洗准备过程。分别地,这些光催化剂被XRD,N2物理吸附,UVvis弥漫的反射光谱学,TEM和拉曼光谱学描绘,他们的photocatalytic活动被把methy1橘子(瞬间)用作模型混合物测试。另外,合并的CNT的数量的效果,锻烧温度和在合成光催化剂的photocatalytic活动的催化剂的数量系统地被调查。结果证明CNTs/TNTs合成展览高得多的photocatalytic活动比TNT或CNT的独自一个。

  • 标签: 复合光催化剂 碳纳米管 甲基橙 降解效率 光催化活性 透射电子显微镜
  • 简介:Theboundaryelementmethodwasimprovedforthe2Delasticcompositeswithrandomlydistributedinclusions.Thisproblemcanbereducedtoaboundaryintegralequationforamulti-connecteddomain.Further,consideringthematricesofthetractionsanddisplacementsforeachgroupoftheidenticalinclusionwerethesame,aneffectivecomputationalschemewasdesigned,sincetheordersoftheresultingmatrixequationscanbegreatlyreduced.Numericalexamplesindicatethatthisboundaryelementmethodschemeismoreeffectivethantheconventionalmulti-domainboundaryelementmethodforsuchaproblem.Thepresentschemecanbeusedtoinvestigatetheeffectivemechanicalpropertiesofthefiber-reinforcedcomposites.

  • 标签: 包含 数字模拟 边界元素 2D弹性 光学纤维