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500 个结果
  • 简介:<正>(a1/2)2和(a2)1/2兄妹俩,一来到花果山就受到众猴儿的青睐,争相和他俩交朋友,哪知有的小猴对他俩不礼貌,有时还受到了委屈,于是他俩就到猴王那里去告状,兄妹俩来到猴王面前,深深行了个鞠躬礼说:“报告猴王,小猴儿常把我俩张冠李戴,用我俩来解题时,

  • 标签: 算术平方根 非负数 花果山 二次根式 彻底认识 彻底了解
  • 简介:8,8′-Dibromo-6,6′,7,7′-tetramethoxy-5,5′-diisopropyl-3,3′-oxydimethylenedinaphtho[2,1-b:2′,1′-d]furan,C32H30Br2O;M.W.=670;triclinic;spacegroupP1;a=8.896(2),b=10.216(1),c=10.423(1)A,α=108.48(1),β=119.36(1),γ=99.26(1);V=723.5A3;Z=1,Dcal.=1.479g.cm-3.MoKα=28.11cm-1,F(000)=326,T=293K.Thestructurewassolvedbydirectmethodandfull-matrixleast-squaresrefinementconvergedatR=0.034for2377observedreflections.Theoxygenatominseven-memberedringexistsinadisorderedarrangement.Bothbisnaphthaleneandoxygen-containingfive-memberedringhaveplanarconformationswithdihedralangle6°,showingmarkedaromaticfeature.

  • 标签: FURAN derivative dibromo-6 6 TRICLINIC membered planar
  • 简介:Twonewdicyanamidecoordinationpolymers,{Mn(dmpz)[N(CN)2]2}2(1)and{Cu(dmpz)[N(CN)2]2}2(2)(dmpz=3,5-dimethylpyrazole),weresynthesizedandcharacterizedbysinglecrystalX-raydiffractionanalysisandIRspectroscopy.In1and2themetalionshavetwodifferentcoordinationmodes,whereoneiscoordinatedtofourdicyanamideanionsandtwomonodentatedmpzmoleculestoformaslightlydistortedoctahedralgeometry,whiletheotheradoptsoctahedralgeometry,surroundedbyfournitrileNatomsandtwoamideNatomsofthedicyanamideanions.Bothcomplexescontaintwoalternatingchainsthatareparalleltoeachother.

  • 标签: 氰氨基化合物 聚合体 晶体结构 3 5-二甲基吡唑
  • 简介:IntroductionThemostbasicconditionsforfeedbackclosed_loopcontrolofmanipulatorsarethefinestructureandtheefficientreal_timecompu...

  • 标签: ROBOT DYNAMICS GENERALIZED d’Alembert EQUATIONS
  • 简介:如果X是一条弧或一个圆,那么,X上没有广泛的同胚,是众所周知的。在我们证明那的这篇论文,X上没有广泛的Z~d行动,它回答以前我们提出的二个问题。在1979,鬃毛证明在无限的维的空格没有广泛的同胚。与这结果相反,我们在一个无限的维的空格构造广泛的Z~2action。我们也在Z~2在零个维的空格而是没有元素构造一个广泛的Z~2行动是广泛的。

  • 标签: 群论 同拓扑 扩展性 空间特性
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  • 简介:STUDIESONGLYCOSIDESXVII─STEREOSELECTIVESYNTHESISOF(,6-DIMETIIOXY-4-ETHOXYCARBONYL)PHENYL6-O-ACETYL-2,3,4-O-BENZYL-β-D-GLUCOP...

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  • 简介:ThecrystalstructureofDi-nitratobis(ethylcaprolactam)uranyl(Ⅱ)UO2[CH2(CH2)4CONC2H5]2(NO3)2wasestablishedbyasingle-crystalX-raydiffractionstudy.Itistriclinie,spacegroupP1,witha=7.171(2),b=8.655(3),c=10.182(5)A,α=78.27(3),β=70.63(3),γ=81.76(3)°,V=581.7(4)A3,Z=l,Dc=1.94g.cm-3.FinalRvalueis0.0218.Theresultrevealsthaturanylioniscoordinatedtosixoxygenatoms,twoofthemarefromtwocarbonylgroupsofethylcaprolactamandtheotherfourarefromtwonitrategroups.

  • 标签: carbonyl coordinated nitrate NITRATOBIS NO3 ONC2H5
  • 简介:SAMisanetwork-distributeddatamanagementsystemdevelopedatFermilabforusewithRunIIdata,ItisbeingEmployedbytheD0Experimenttostore,manage,deliver,andtrackprocessingofalldata.Wedescribethedesignandfeaturesofthesystemincludingresourcemanagementanddatatransfermechanisms,WeshowtheoperationalexperienceD0hasaccumulatedtodateincludingdataacquisitionprocessing,andalllevelsofaccessanddelivery.Wepresentvariousconfigurationsofthesystemanddescribetheiruseinthecollaboration.

  • 标签: SAM 数据处理系统 D0实验
  • 简介:ANINTERSECTIONPROPERTYOFTHESIMPLERANDOMWALKSINZ ̄dZHOUXIANYIN(DepartmentofMathematics,BeijingNormalUniversity100875,China)Abst...

  • 标签: EFFECTIVE resistance SIMPLE RANDOM WALK INTERSECTION
  • 简介:Thispaperderivesfirstordernecessaryandsufficientconditionsforunconstrainedconed.c.Programmingproblemswheretheunderlinedspaceispartiallyorderedwithrespecttoacone.Theseconditionsaregivenintermsofdirectionalderivativesandsubdifferentialsofthecomponentfunctions.Moreover,conjugatedualityforconed.c.Optimizationisdiscussedandweakdualitytheoremisprovedinamoregeneralpartiallyorderedlineartopologicalvectorspace(generalizingtheresultsin[11]).

  • 标签: 锥d.c.最优化 共轭对偶 弱对偶定理 次梯度 多目标优化 方向导数
  • 简介:Thenew-typetractionboundaryintegralequationsdevelopedbyHuandwithnohypersingularintegralareappliedtoanalysisof3Dfinitecrackedbodies.Anumericalalgorithmforgeneral3Dproblemsandasemi-analyticaloneforaxisymmetricproblemsarepresented.Someexamplesofthickplatesandcylindricalcolumnsincludingpenny-shapedcrack(s),andrectangularplatesincludinganellipticalcracknormaltothesurfaceareanalyzed.Thecomparisonbetweenpresentresultsandthoseinliteratureshowsthehighaccuracyandeffectivenessofthepresentmethod.

  • 标签: principal integral crack stress INTENSITY factor
  • 简介:Thispapergivesthedefinitionsandsomepropertiesofε-directionalderivateandε-subgradientsofcone-convexfunction.Fromthem,theoptimalityconditionsoflocalandglobaloptimalpointofunconstrainedcone-d.c.programmingaregained.Atlast,thedualitytheoremsofthisprogrammingarepresented.

  • 标签: ε-定向导出数 ε-子斜度 最优化条件 对偶定理 凸函数
  • 简介:  Enantioimericallypure1,l'-bi-2-naphthol(BINOL)1anditsderivativesareimportantchiralligandsandauxiliariesforanumberofasymmetrictransformations1suchasaldolcondensations,alkylations,Diels-Alderreactions,Michaeladditions,epoxidations,etc.Opticallypure1andtheirderivativeshavealsobeenusedextensivelyinchiralrecognition,chiralseparationandintheconstructionoffunctionalisedmaterials2.Furthermore,(R)-and(S)-BINOLarealsofundamentalstartingmaterialsforthesynthesisofalargevarietyofotherchiralbinaphthylssuchasMOP(2c),NOBIN(2d)andBINAP(2e).Asaresultthedevelopmentofefficientandeconomicmethodsforthepreparationofopticallypure1hasattractedmuchattentioninrecentyears3andnovelmethodsfortheresolutionof(±)-1continuetobedeveloped.……

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  • 简介:Themononuclearcomplex,[NtCl2(trzCHzCHzCOPh)4]·6H2O(trz=1,2,4-triazole),wassynthesizedanditsstructurewasdeterminedbysinglecrystalX-raydetermination.Itcrystallizesinthemonoclinicsystem,spacegroupP21/c,withlatticepa-rameters:a=0.80391(2)nm,b=1.06215(2)nm,c=2.90133(2)nm,β=94.792(1)°andZ=2.EachnickelatomiscoordinatedbyfourNatomsoftriazolefromfourβ-(1,2,4-IriHole-1-yl)propiophenoneligandsandtwochlorideanionsinarrangementwithoctahedralcoordinationgeometry.Inadditiontothecoordinatingnickelcomplex,therearesixunco-ordinatedwatermolecules.TheNi—Ndistanceis0.24865(8)nmandtheNi—Ndistaneesareintherangeof0.2072(2)to0.2099(2)nm,respectively.Inthesolidstate,theUtiecom-poundformsthreedimensionalnetworkstructurethroughhy-drogenbonds.Theintermolecularhydrogenbondsconnectthe[NiCl2(C2H2N3CH2CH2COPh)4]andH2Omoieties.Thedeepgreencrystalswerealsoexaminedbyelementalanalysis,FT-IRandUVspectra,whichareinagreementwiththestructuralda-ta.

  • 标签: 单晶结构 二氯镍 镍(Ⅱ)配合物 六水配合物 ·6H2O 八面体
  • 简介:theAlternatingSegmentCrank-Nicolsonschemeforone-dimensionaldiffusionequationhasbeendevelopedin[1],andtheAlternatingBlockCrank-Nicolsonmethodfortwo-dimensionalproblemin[2].Themethodshavetheadvantagesofparallelcomputing,stabilityandgoodaccuracy.Inthispaperforthetwo-dimensionaldiffusionequation,thenetregionisdividedintobands,aspecialkindofblock.ThismethodiscalledthealternatingBandCrank-Nicolsonmethod.

  • 标签: 二维空间 分布函数 有限微分方程 边界条件
  • 简介:Thecopper(Ⅱ)complex[Cu3(nta)2(azpy)2(H2O2)]·6H2O(nta=nitrilotriacetate,azpy=4,4′-azobispyridine)hasbeensynthesizedandcharacterized.TheX-rayanalysisrevealsthattherearetwokindsofcopper(Ⅱ)coordinationenvironments.Cu(1)hasadistortedsquareplanesymmetryandCu(2)hasadistortedoctahedralsymmetry.Cu(1)islinkedtoCu(2)throughntaandboundtoCu(1C)byazpy,andCu(2)islinkedtoCu(2A)throughazpy,whichextendstotwo-dimensionalnetworkwithlargerhombus1.2nm×1.7nm.

  • 标签: 合成 结构 二(次氮基三乙酸酯)二(偶二嘧啶酰胺)二水三铜络合物