简介:Thispaperreportstwolanthanidecomplexesofformula(C9H7)Ln(C8H8)·(THF)2whereLnisProrNd,C9H7isindenyl,andC8H8iscyclooctatetraene(COT).ThecomplexeswerepreparedbythereactionofLnCl3withK(C9H7)andK2(C8H8)inTHF.(C9H7)Pr(C8H8)·(THF)2crystallizesinTHFat-15℃inthemonoclinicspacegroupP21:withunitcelldimensionsa=8.446(0),b=10.083(2),c=13.407(3),β=105.48(1)°,V=1100.43(35)3,Dc=1.52g/cm3andZ=2.ThefinalRvalueis0.033,Rwvalueis0.030,respectively.In(C9H7)Pr(C8H8)·(THF)2afive-memberedringcentroidofC9H7,theC8H8ringcentroidandthetwooxygenatomsfromthetwoTHFmoleculesformadistortedtetrahedralgeometryaroundthemetal.
简介:ThereactionofNdCl3withlithiummethylnaphthalenein1:2moleratioinTHFgeneratesblackpowder.Thepowderreactswithcyclooctatetraene(COT)inTHFtoformthetitlecomplex.[Li(THF)4Nd(C8H8)2]·2THFcrystallizesinthemonoclinicspacegroupP2/cwithunit-celldimensionsa=1.7858(7)nm,h=1.3243(4)nm,c=1.8086(6)nm.β=106.52(4)°,V=4.10nm3andDc=1.268g/cm3forZ=4.F(000)=1660,R=0.0774,Rn=0.0733.Thecomplexconsistsofdiscreteion-pairandtwoTHFmoleculesadduct.Intheanion,theneodymiumatomiscoordinatedbytwoCOTrings.ThestructureofthecationshowsthatthelithiumatomisattachedwithTHFmoleculesonly.
简介:Catalyticcombustionofpropane-airmixturewasinvestigated.Platinumcatalystsoveraflatstainlesssteelwithγ-aluminawashcoatwereemployed.Theemployedburnerhasthreecatalystssetparalleltothemixtureflow,spacedatanintervalof5,10and15mm.Bothexperimentandnumericalsimulationweremadeatinlettemperatureof553K,inletvelocityof3to7m/sandequivalenceratioof0.3to0.5.Inthenumericalsimulation,two-dimensional,steadystatemodelwasdevelopedtocalculatethetemperatureandspeciesconcentrationingas-phase.Inthismodel.chemicalreactiononthecatalystsurfaceandthatinthegasphasewereassumedtooccurinthree-steps.Thenumericalresultsshowgoodagreementwithexperimentalresults.Itwasfoundthatthepropertiesofthecatalyststronglyaffectthecatalystsurfacetemperature.Especially,thethermalconductivityofcatalysthasagreateffect,whiletheemissivityofcatalysthaslesseffect.
简介:4+4等于8,2+6等于8,6+2也等于8,但有人却奇迹般地让2+6或6+2大于了4+4,这是为什么呢?事情还要从美国的金门大桥说起。金门大桥是“4+4”8车道模式,但由于上下班的车流在不同时段出现两个半边分布不均匀的现象,
简介:采用铜(Ⅱ)盐和3,5-二氯水杨醛缩丝氨酸以及4,4′-联吡啶在乙醇水溶液中合成了具有二维层状的配位聚合物.通过元素分析、红外光谱对该配位聚合物进行了表征,并利用X射线单晶衍射仪对其结构进行了鉴定.晶体结构表明,该标题配合物属三斜方晶系,空间群C2/c,晶胞参数为a=2.711(3)nm,b=2.711(3)nm,c=4.977(5)nm;α=90.00°,β=90.00°,γ=120.00°,V=3.1678nm^3,Z=18,Dc=1.173g·cm^-3,F(000)=11448,μ=0.807mm-1,R1=0.0788,wR2=0.1872.
简介:ACupro-8-thioquinolinecoordinationpolymer,[Cu^I(C9H6NS)]n,wassynthesizedbymethano-thermalreactionofCuCland8,8′-dithiodiquinoline(dtdq)inamolarratioof2:1at160℃for7d.X-Raysinglecrystalstructuredeterminationrevealedtheformationofaone-dimensionalstructurebelongingtomonocliniccrystalsystem,spacegroupP21/cwithcellparametersa=0.8043(1)nm,b=1.8949(3)nm,c=1.1048(1)nm,β=110.109(4)°,V=1.5810(4)nm^3andZ=4,Thecrystalwasfoundtobestableuptoapproximately300℃bythermalanalysisandhaveanenergygap(Eg)of2.0eVexhibitedbyUV-Vis-NIRreflectancespectrum.
简介:Thispaperreportsthattheetchingmorphologyofdislocationsin8°off-axis4H-SiCepilayerisobservedbyusingascanningelectronicmicroscope.Itisfoundthatdifferenttypesofdislocationscorrespondwithdifferentdensitiesandbasalplanedislcation(BPD)arrayandthreadingedgedislocation(TED)pileupgroupliealongsomecertaincrystaldirectionsintheepilayer.Itisconcludedthattheelasticenergyofthreadingscrewdislocations(TSDs)ishighestandTEDsislowestamongthesedislocations,sothedensityofTSDsislowerthanTEDs.TheBPDscanconverttoTEDsbutTSDscanonlypropagateintotheepilyerinspiteofthehigherelasticenergythanTEDs.ThereasonoftheformofBPDsarrayinepilayeristhatthebigstepalongthebasalplanecausedbyfacedefectsblockedtheupstreamatoms,andTEDspileupgroupisthatthedislocationsslideisblockedbydislocationgroupsinepilayer.