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38 个结果
  • 简介:Thispaperisconcernedwithexperimentalandnumericalresearchon3DflowpastprismaticturbinecascadeSE1050(knowninQNETnetworkasopentestcaseSE1050).Theprimarygoalwastoassesstheinfluenceoftheinletvelocityprofileontheflowstructuresintheinterbladechannelandontheflowfieldparametersatthecascadeexitandtocomparethesefindingstoresultsofnumericalsimulations.Investigationsof3Dflowpastthecascadewithnon-uniforminletvelocityprofilewerecarriedoutbothexperimentallyandnumericallyatsubsonic(M2is=0.8)andattransonic(M2is=1.2)regimeatdesignangleofincidence.Experimentaldatawasobtainedusingatraversingdevicewithafive-holeconicalprobe.Numerically,the3DflowwassimulatedbyopensourcecodeOpenFOAMandin-housecode.AnalysesofexperimentaldataandCFDsimulationshaverevealedthedevelopmentofdistinctivevortexstructuresresultingfromnon-uniforminletvelocityprofile.Originofthesestructuresresultsinincreasedlossofkineticenergyandspanwiseshiftofkineticenergylosscoefficientdistribution.Differencesfoundbetweenthesubsonicandthetransoniccaseconfirmearlierfindingsavailableintheliterature.ResultsofCFDandexperimentsagreereasonablywell.

  • 标签: 实验数据 数值模拟 三维流动 涡轮叶栅 跨音速 SE
  • 简介:由中科院西安光学精密机械研究所研发的国内首台高速3D内窥OCT影像系统成功问世。该设备使用自主研发的微型光纤探头,可深人心脏病患者血管栓塞处进行光学相干断层(OCT)扫描,获得栓塞处清晰的3D内窥影像。利用该影像技术可帮助医生在心脏手术中对支架安放位置精确定位,并可帮助医生实现对病变血管形态及心脏支架置人状况进行离线直接观察,其成像速度及分辨率都远超现有的血管超声(IVUS)和心脏X光(DSA)技术,对于有效预防支架再狭窄和血栓支架的形成、实现心肌梗死的早期筛查和有效预防以及研究和评价心脏支架安全陛有革命性意义。

  • 标签: 影像系统 OCT 内窥 3D 心脏病患者 血管栓塞
  • 简介:WepresentthetemperaturedependentelectricaltransportmeasurementsofAg/Si(111)-(√3×√3)R30°bytheinsitumicro-four-pointprobemethodintegratedwithscanningtunnelingmicroscopy.Thesurfacestructurecharacterizationsshowhexagonalpatternsatroomtemperature,whichsupportstheinequivalenttriangle(IET)model.Ametal-insulatortransitionoccursat-115K.Thelowtemperaturetransportmeasurementsclearlyrevealthestronglocalizationcharacteristicsoftheinsulatingphase.

  • 标签: surface CONDUCTIVITY METAL-INSULATOR transition LOCALIZATION SCANNING
  • 简介:Basedonconsolidationequationsproposedforunsaturatedsoil,ananalyticalsolutionfor1Dconsolidationofanunsaturatedsingle-layersoilwithnonhomogeneousmixedboundaryconditionisdeveloped.Themixedboundaryconditioncanbeusedforspecialapplications,suchastestsoccurinlaboratory.Theanalyticalsolutionisobtainedbyassumingallmaterialparametersremainconstantduringconsolidation.Inthederivationoftheanalyticalsolution,thenonhomogeneousboundaryconditionisfirsttransformedintoahomogeneousboundarycondition.Then,theeigenfunctionandeigenvaluearederivedaccordingtotheconsolidationequationsandthenewboundarycondition.Finally,usingthemethodofundeterminedcoefficientsandtheorthogonalrelationoftheeigenfunction,theanalyticalsolutionforthenewboundaryconditionisobtained.Thepresentmethodisapplicabletovarioustypesofboundaryconditions.Severalnumericalexamplesareprovidedtoinvestigatetheconsolidationbehaviorofanunsaturatedsingle-layersoilwithmixedboundarycondition.

  • 标签: 英文摘要 编辑工作 优秀论文 医学期刊
  • 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.

  • 标签: Ni catalyst ALUMINA CO METHANATION synthetic
  • 简介:许多人都了解RADAR的概念一无线电探测和测距(Ra—dioDetectionandRanging),该技术通过发射无线电频率波在大气层传输,接触目标后反射回到系统进行处理,从而得出目标距离。近年来,电子扫描阵列使这一技术发生了革命性转变,可将无线电波以特定方向传输,无需机械移动。

  • 标签: 激光测距 光学相控阵 应用 无线电探测 RADAR 无线电频率
  • 简介:用机械合金化方法制备了(FeAl3)75Zr25和(FeAl3)50Zr50非晶态合金,用X射线衍射仪和热分析仪对制备的非晶态合金的结构特性及热稳定性进行了研究,用振动样品磁强计对(FeAl3)75Zr25和(FeAl3)50Zr50混合粉末在机械球磨过程中的磁性变化进行了研究,并对其晶化产物及其晶化后合金的磁性进行了分析。结果表明:(FeAl3)75Zr25的晶化产物为Fe3Zr和Al1.65Fe0.33Zr;(FeAl3)50Zr50非晶态合金的晶化产物为FeZr2和AlZr2。(FeAl3)75Z

  • 标签: 机械合金化 非晶合金 磁性能