简介:年终岁尾,又到了盘点的时候。2016年1月,重庆,20年来第一场大雪。瑞雪兆丰年,脱贫攻坚忙。这是一次向人民作出的庄严承诺。我们看到:市委、市政府坚决贯彻中央的决策部署,以空前的领导重视程度、空前的政策聚焦力度、空前的资金投入强度、空前的社会参与广度、空前的舆论宣传深度,立下愚公移山志,咬定目标、苦
简介:Lid-drivenmixedconvectionhasbeengivenimmenseimportanceduetoitswiderangeofapplications.AT-shapedcavityisintroducedandpertinentparameterscontrollingmixedconvectionphenomenonareanalyzedinthispaper.Water-Al2O3nanofluidisconsideredinsidethecavitytoaugmentheattransferrate.Galerkinweightedresidualmethodoffiniteelementanalysisisappliedforthenumericalsimulations.Numericalsolutionisobtainedfordifferentsolidvolumefractionsofnanofluid(?=0-0.15),Grashofnumbers(Gr=0.1?5000)andReynoldsnumbers(Re=0.31?1000)inlaminarflowregime.Specialattentionisgivenontheanalysisofflowatthepuremixedconvectionregime.ItisfoundthatGrashof,ReynoldsandRichardsonnumbersalongwithsolidvolumefractionofnanofluidhavesignificanteffectonheattransfercharacteristicsinsidethecavity.ResultsarepresentedusingstreamlineandisothermcontoursalongwithrelatedvariationofaverageNusseltnumbersoftheheatedwallandaveragefluidtemperatureinsidethecavity.
简介:为了明确团聚现象及表面性质对ZnS纳米材料发光性质的影响,采用SiO2对ZnS材料进行了表面修饰,并对ZnS及ZnS/SiO2复合材料的光学性质进行对比研究。采用吸收光谱分析了包覆前后光吸收性质的差异,发现SiO2包覆后ZnS纳米材料的带边由333nm红移至360nm。为了研究ZnS纳米材料与ZnS/SiO2纳米复合材料的光发射性质,分别对含纳米材料的水溶液样品及粉末样品的发光光谱进行了采集。对比研究的结果表明,SiO2包覆后ZnS纳米材料在蓝紫光区的发光得到了明显增强。以氙灯作为激发光源所获得荧光光谱显示ZnS/SiO2粉末样品发光的积分强度增大为原来的17.5倍,但相同条件下针对溶液样品的测试结果显示其发光强度只增大了1.1倍,这种增强可用SiO2的存在抑制了ZnS纳米粒子间的团聚来解释,且这一推断由325nm紫外激光激发下获得的光致发光数据进行了验证。
简介:Themainrequirementsforbatteryseparatorsarehighporositywhichcanservepathwaysoflithiumionandspaceforgelelectrolytestoimpregnateinamembraneandmechanicalstrengthtoalloweasyhandlingforbatteryassembly.Generally,itappearsthetrade-offrelationshipbetweentheporosityandmechanicalstrengthofthemembrane.PVdFcompositemembranescontainingnano-sizeclayswereusedtoimprovethemechanicalstrengthofthemembranewithoutaffectingthemembraneporosity.Thecompositemembraneswerepreparedbyphaseinversionmethodcontrollingthemembranepreparationconditionssuchasretentiontime.Theresultantmembranesshowincreasedmechanicalpropertieswithsimilarmembraneporosityaround80%comparedtothepristinePVdFmembrane.Incorporationofnonoclaycanbeconsideredasaneffectivemethodtoimprovethemechanicalstrengthinporousmembranesupports,especiallyinaseparator.
简介:Thispaperanalysestheoreticallytheeffectoftransportationandhousingsubsidiesonurbansprawl,modalchoicedecisionsandurbanspatialstructureusingaspatialgeneralequilibriummodelinamonocentriccitywithtwotransportmodes.Ouranalysisshowsthatpublictransitsubsidyleadstourbanshrink,whilstsubsidizingautomobileandhousingmakethecitysprawl.Wealsofindtheeffectsoftheotherfactorsonurbansprawl,suchashouseholdsincomeanddemand,rurallandrent,theincometaxrate,thetotalfixedcostofpublictransitandautomobileandthetravellingmarginalcostofpublictransitandautomobile.Furthermore,thispaperalsostudieshowtomaximizetheurban-area-widespatialequilibriumutilitylevel.