学科分类
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246 个结果
  • 简介:Anewμ3-Otriiron(Ⅲ)complex[Fe3O(OBz)6(CH3OH)3](NO3)(CH3OH)2(HOBZ=benzoicacid)hasbeensynthesized,itsstructurehasbeendeterminedandvariabletemperaturemagneticsusceptilityhasalsobeenmeasured.Inthemolecule,threeironatomsformedanequilateraltrianglewithu3-Oincenter.ThefittingtothemagneticsusceptibilityshowedthatanintramolecularantiferromagneticexchangeinteractionoccurredbetweenironatomswithJ=-25.51cm-1,andaweakerintermolecularantiferromagneticexchangeinteractionoccurredwithzJ’=-2.30cm-1.

  • 标签: Crystal STRUCTURE MAGNETIC exchange triiron complex.
  • 简介:Pureandneodymium-dopedgadoliniumcalciumoxoboratecrystalsofhighqualityweregrownbytheCzochralskimethod.Theorientationofcrystalwaspreciselydetermined,andthesamplesformeasurementswereprepared.Throughsynchrotronx-raytopographyandhigh-resolutionx-raydiffractometry,thetwinstructurewasdiscovered.Somepropertiessuchasthefigureofmeritvalue,anddielectric,piezoelectric,andelasticconstantsweremeausuredalongwithadiscussionoftheanisotropyofthelaserproperties.

  • 标签: GdCa4O(BO3)3晶体 钕掺杂 硼酸盐晶体 Nd:GdCa4O(BO3)3晶体 晶体生长 形貌学
  • 简介:[Co3(1,2-S2C6H4)3(PPh3)3][CoBr3(DMF)].sol(1,sol=CHCl3,O(C2H5)2,H2O)wasobtainedfromthereactionofCoBr(PPh3)3withNa2(S2C6H4)inchloroform.TheCo3coreinthecationof1exhibitsametal-metalbondedisoscelestriangle,inwhichthetwolongerCo-CobondsarebothbridgedbyS2C6H4ligandsontwosidesofthetriangleplanerespectively,whilethebottomshortCo-CobondisbridgedbythethirdbidentateS2C6H4ligand.Aseriesofpolynu-clearcobaltclustercompoundswithphosphine,thiolateand/orsulphurligandswerepreparedbylowoxidationstateCo+withthiolatesinorganicsolvents.Thesetri-,tetra-,hexa-,heptanuclearclustercompounds1-8withvarioustypesofcrystalstructurescanbeviewedasthecondensedpolynuclearcobaltcomplexesthatthecobaltatomframeworkswithsulphurbridgedwerebuiltthroughthesmalltriangularunitsof[Co3S3nL3](n=1,2)withorwithout[CoL](L=PR3,Br,Cl,5-C5H5)fragments.

  • 标签: POLYNUCLEAR cobalt THIOLATE PHOSPHINE structure.
  • 简介:MP3风靡我们的时候,我们就开始患上MP3疯魔症——眼睛睁开的第一秒,便搜索最爱的MP3,低头走路,孤立进食,默默无语……自始至终,活在一个人的世界里,你说,这不是疯了是怎么了?

  • 标签: MP3 设计 整机 电池
  • 简介:Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/Organophilicmontmorillonite(PHBV/OMMT)nanocompositeswerepreparedandthebiodegradabilityofthePHBV/OMMTnanocompositeswasstudiedbyacultivationdegradingmethodinsoilsuspension.TherelationshipbetweenstructureandbiodegradabilityofPHBV/OMMTnanocompositeswasinvestigated.TheresultsshowedthatthebiodegradabilityofPHBV/OMMTnanocompositesdecreasedwithincreasingamountofOMMTanditwasrelatedtothenumberofPHBVdegradingmicroorganismsindegradationenvironment,theanti-microbialpropertyofOMMTandthedegreeofcrystallinityofthenanocomposites.

  • 标签: 生物降解能力 聚(3-羟基丁酸酯-co-3-羟基戊酸酯) 蒙脱土 纳米复合物 环境友好物质 可降解塑料
  • 简介:ELECTRON TRANSFER BETWEEN Eu+ AND Ce+ IN SrMgF4 MATRIXELECTRONTRANSFERBETWEENEu+ANDCe+INSrMgF4MATRIX¥YingWU;Ch...

  • 标签:
  • 简介:YbxY1-xAl3(BO3)4(x=0.1,0.07and0)crystalshavebeengrownbythefluxmethod.ThegrowthdefectsofYbxY1-xAl3(BO3)4crystalsweredetectedbyX-raytopography.ItisfoundthattheperfcetionofYbYABcrystalwithlowYbdopantisbetterthanthatwithhighYbdopant.InYb0.1Y0.9Al3(BO3)4crystal,growhtbands,growthboundaries,grown-indislocationsandinclusionswereobserved.Howver,thedensitiesofgrowthdefectsforYb0.07Y0.93Al3(BO3)4andYAl3(BO3)4arelowandnoobviousinclusionsareobservedinthesecrytals.Inaddition,growthtwinswrerdetectedinYbxY1-xAl3(BO3)4crystalbyusingthechemicaletchingmethod.ItisfoundthatthegrowthtwinsoccurfrequentlyinYb0.01Y0.9Al3(BO3)4crystalwhereasnogrowthtwinappearsinYAl3(BO3)4crystal.Basedontheexperimentalobservations,theformationmechanismofgrowthtwinsisdiscussed.Inthemeantime,theeffectivemeasuresforreducingthegrowthtwinsanddefectsareproposed.2001ElsevierScienceB.V.Allrightsreserved.

  • 标签: YbxY1-xAl3(BO3)4晶体 晶体生长 结构缺陷 硼酸盐晶体 形貌学 X射线
  • 简介:Abstract.Inthispaper,weintroduceanewapproachtocharacterizetheisomor-phismsofcirculantdigraphs.Intermsofthismethod,wecompletelydeterminetheisomorphicclassesofcirculantdigraphsofdegree3.Inpsrticular,wecharacterizethosecirculantdigraphsofdegree3whichdon''tsatisfyJkdAm''sconjectttre.

  • 标签: 循环行列式 特征值 运算方法 矩阵 主要结果
  • 简介:让f:M→R~3是有非退化的秒的面向的表面基本形式。我们由H和K表示它的吝啬的弯曲和高斯弯曲。然后f的Laguerre体积,由L(f)=∫(H~2定义-K)/KdM,一在Laguerre转变下面不变。功能的L的批评表面被称为Laguerre最小的表面。在这篇论文,我们学习在由使用拉久雷·高斯的R~3的最小的表面印射的theLaguerre。这被知道最小的表面有的genericLaguerre有一样的高斯地图的双Laguerre最小的表面。在这篇论文,我们证明不是Laguerre的任何表面最小被它的LaguerreGaussmap特别地决定。我们也证明圆范围是在R~3的唯一的紧缩的Laguerre最小的表面。并且我们与消失的Laguerre形式在R~3给表面的一条分类定理。

  • 标签: Laguerre值 几何表面 高斯映射 Laguerre转换
  • 简介:Inthispaper,weprovethatifGisaplanegraphwithout4-,5-and7-circuitsandwithoutintersectingtriangles,thenforeachfacefofdegreeatmost11,any3-coloringoftheboundaryoffcanbeextendedtoG.ThisgivesapositivesupporttoaconjectureofBorodinandRaspaudwhichclaimsthateachplanegraphwithout5-circuitsandintersectingtrianglesis3-colorable.

  • 标签: 平面图 邻集 顶点 路径循环
  • 简介:Copolymerizationofstyrene(St)andisoprene(IP)wascarriedoutwithacatalystsystemcomposeaofanhydrouslanthanidechloridehexamethylphosphoramidecomplex(LnCl3·HMPA)andaluminumorganiccompound(AOC).Amongthecatalystsexamined,catalystNdCl3·HMPA/AI(i-Bu)3showedahighactivityinthecopolymerizationundercertainconditionsgivingcopolymers(5%—15%Stcontent)withhighcis-1,4microstructureinIPunits(>95%).TheeffectsofHMPA/Ndmolarratio,Al/Ndmolarratio,monomer/Ndmolarratio,Stfeedratio,andthereactiontimeoncopolymerizationwereexaminedwiththiscatalyticsystem.Theobtainedcopolymerswerecharacterizedby^1Hand^13CNMRspectroscopiesandgel-permeationchromatography(GPC).

  • 标签: 异戊二烯 苯乙烯 氯化镧 共聚反应 六甲基磷酰胺 铝有机化合物
  • 简介:MHP(CH3OOH)和EHP(CH3CH2OOH)的电离精力被方法根据在6-311+G*基础的Koopmans定理设置了的光谱学(足)测量和两个Gaussian-2(G2)计算和Hartree-Fock(HF)第一次铺平的HeI光电子决定了。MHP和EHP的PE系列的任务和描述被G2和HF计算也支持。MHP和EHP的第一个电离精力分别地是9.87和9.65eV。在空气的EHP的更高的溶解度被归因于他们的更低的电离精力价值。

  • 标签: 电光子分光光谱 量子计算 甲基过氧化氢 乙基过氧化氢 哈特里-福克法
  • 简介:在这篇文章,在三维的Lorentz空间的类似的运动的性质被调查。另外,在速度之间的一些几何结果和在一个空间运动的一个点的加速向量被获得。给词调音:类似的运动;空间kinematics;Lorentzian几何学

  • 标签: 同位运动 空间运动学 Lorentzian几何学 加速度向量