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500 个结果
  • 简介:Abosonicconstruction(withcentralchargec=2)ofLiealgebrasW1+∞andW1+∞(glN),aswellasthedecompositionsintoirreduciblemodulesaredescribed.AndforW1+∞,whenrestrictedtoitsVirasorosubalgebraVir,abosonicconstructionandthesamedecompositionforVirareobtained.

  • 标签: 玻色子表示法 李代数 Virasoro超代数 不可约模数
  • 简介:Parametersforthe3W1sourceatBSRFweredeterminedinboththededicatedandparasiticmodeandtheirsuitabilityforproteincrystallographybeamlineatBSRFwererealized.Itisdiscussedthatthephysicsmotivationandthedesignofthe3W1iscomparedwithsimilarexperimentalstationsattheBrazilianLightSourec(1.37Gev)andMax-IIinSweden(1.5GeV).Thephotonfluxfromthe3W1sourcdisabout2×10^11photon/smAinthewavelengthrangeof2.0-0.9Ainparasiticmodeand50-80timeshigherinthededicatedmode.Boththededicatedandparasiticmodesaresuitableformacromolecularstructureexperiments.2001ElsevierScienceB.V.Allrightsreserved.

  • 标签: BSRF 北京同步辐射装置 蛋白质 生物化学 结构分析 结晶学
  • 简介:At-hyperwheel(t≥3)oflengthl(orW(t)lforbrevity)isat-uniformhypergraph(V,E),whereE={e1,e2,...,el}andv1,v2,...,vlaredistinctverticesofV=∪eii=1lsuchthatfori=1,...,l,vi,vi+1∈eiandei∩ej=P,j∈/{i1,i,i+1},wheretheoperationonthesubscriptsismodulolandPisavertexofVwhichisdifferentfromvi,1≤i≤l.Inthispaper,theminimumcoveringproblemofMCλ(3,W(3)4,v)isinvestigated.DirectandrecursiveconstructionsonMCλ(3,W(3)4,v)arepresented.Thecoveringnumbercλ(3,W(3)4,v)isfinallydeterminedforanypositiveintegersv≥5andλ.

  • 标签: 最小覆盖问题 一致超图 递归结构 Tgt 直接和 覆盖数
  • 简介:应用标量光场光强的传统定义,推导了具有轴对称性的傍轴标量光束的光强二阶矩的传输规律。在此基础上,给出了光束的束腰半径、远场发散角及光束质量因子M2,并证明了光束质量因子M21。应用标量光场光强的精确定义,计算了非傍轴标量高斯光束的质量因子,结果表明:当ω0λ时,光束质量因子M2可以小于1,并随光束的束腰半径趋于零而趋向于零;ω0>λ时,高斯光束的质量因子M2非常接近于1,且随光束束腰半径的增大迅速趋向于1。此外,文章还对一些相关的问题进行了讨论。

  • 标签: 傍轴标量光束 非傍轴标量高斯光束 光强二阶矩 光束质量因子
  • 简介:Inthispaper,wegetW1,p(Rn)-boundednessfortangentialmaximalfunc-tionandnontangentialmaximalfunction,whichimprovesJ.Kinnunen,P.LindqvistandTananka’sresults.

  • 标签:
  • 简介:3-(2-Hydroxyphenyl)-6-(4-nitrophenyl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine,C16H11N5O3S,waspreparedbythecyclizationof3-(2-hydroxyphenyl)-4-amino-5-mercapto-1,2,4-triazolewith2-bromo-4-nitroacetophenone.Thecompoundwascharacterizedbymeansofelementalanalysis,IR,1HNMR,13CNMR,massspectrometry,andX-raydiffraction.ThecompoundcrystallizesinamonoclinicsystemwithspacegroupCc,a=2.1853(4)nm,b=2.1192(5)nm,c=1.3526(3)nm,β=95.21(2)°,V=6.238(2)nm3,Dcalcd.=1.505Mg/m3,Z=16,F(000)=2916,R1=0.0501,wR2=0.0427.Acomparisonbetweenthecrystalstructuresof1,2,4-triazolo[3,4-b][1,3,4]thiadiazineand1,2,4-triazolo[3,4-b][1,3,4]thiadiazolewasmadeinthestructuralview.Atwo-dimensionalnetworkisformedbyhydrogenbondsandπ-πstackinginteractions.

  • 标签: 晶体结构 [1 3 4]噻二嗪 制备 光谱表征 Π-Π相互作用
  • 简介:Anewspectralproblemisproposed,andnonlineardifferentialequationsofthecorrespondinghierarchyareobtained.Withthehelpofthenonlinearizationapproachofeigenvalueproblems,anewfinite-dimensionalHamiltoniansystemonR2nisobtained.Ageneratingfunctionapproachisintroducedtoprovetheinvolutionofconservedintegralsanditsfunctionalindependence,andtheHamiltonianflowsarestraightenedbyintroducingtheAbel-Jacobicoordinates.Atlast,basedontheprinciplesofalgebracurve,thequasi-periodicsolutionsforthecorrespondingequationsareobtainedbysolvingtheordinarydifferentialequationsandinversingtheAbel-Jacobicoordinates.

  • 标签: 数学分析 数学理论 应用数学 函数
  • 简介:Underinvestigationinthispaperisa(3+1)-dimensionalvariable-coefficientKadomtsev–Petviashviliequation,whichdescribesthepropagationofsurfaceandinternalwaterwaves.ByvirtueofthebinaryBellpolynomials,symboliccomputationandauxiliaryindependentvariable,thebilinearforms,solitonsolutions,B¨acklundtransformationsandLaxpairareobtained.Variablecoefficientsoftheequationcanaffectthesolitonicstructure,whentheyarespeciallychosen,whilecurvedandlinearsolitonsareillustrated.Elasticcollisionsbetween/amongtwoandthreesolitonsarediscussed,throughwhichthesolitonskeeptheiroriginalshapesinvariantexceptforsomephaseshifts.

  • 标签: LAX对 变系数 孤立波解 方程 BACKLUND变换 双线性形式
  • 简介:FiveC3/C3fluoroquinolonedimerstetheredwithafusedheterocyclicringofs-triazolo[2,1-b][1,3,4]thiadiazolederivedfromantibacterialquinolonesweresynthesizedandcharacterized,andtheirinvitroantitumoractivityagainstL1210,CHOcelllineswasevaluatedviatherespectiveIC50values.

  • 标签: EVALUATION synthesized and characterized ANTITUMOR activity
  • 简介:6/3-(4-Chlorophenyl)-s-triazolo[3,4-b][1,3,4]thiadiazoles(2a-e)and(5a-e)weresynthesizedrespectivelybyintermolecularcyclizationof5-aryl/4-chlorophenyl-4-amino-3-mercapto-1,2,4-triazoles(1a-e)and(4)with4-chlorobenzoicacid/arylacids,whichwerecondensedwithpiperazineunderphasetransfercatalystTBABtoyieldthecorrespondingfreebasesofmonopiperazinederivativesandfollowedtoformwater-solublesalts(3a-e)and(6a-e)withhydrochloricacidingoodyields.Theinvitrobiologicalresultsshowedthatpiperazinegroupconjugatedwiththeabovefusedheterocyclesplayedanimportantroleinantibacterialactivity.ThestructuresofnovelcompoundswereconfirmedbyIR,1HNMR,MSandelementalanalysis.

  • 标签: 哌嗪 相转移 可溶性 抗菌活性 催化合成 药物
  • 简介:The2-C,methylenegroupof1-aroyl-1,2-dihydro-3H-naphtho[2,1-b]pyran-3-ones(2)havebeenshowedtopossessasuperiorreactivitytowardsmanyoforganicreagents.Thena-phthopyrones(2)condensedwitharomaticaldehydestogivethe2-arylidinederivatives(3).Bromin-ationof2gave1,2-dibromo(4)or5-bromo(5)derivativesdependingonthereactionconditions.Thebasecatalyzedadditionorcycloadditionofnaphthopyrones(2)to4-methoxybenzalacetophenonegavetheexpectedMichaeladduct(6)orthecyclicadducts(7-9)dependingonthetypeofcatalyticbaseandreactionconditions.Structuresoftheproductshavebeenestablishedbyelementalanalyses,IRand~1HNMRspectroscopicmethods.

  • 标签: PYRAN REACTIVITY aldehydes aromatic bromo catalyzed
  • 简介:Theground-stateandthermodynamicpropertiesofquantummixed-spinchainsof1/2-1/2-1-1and3/2-3/2-1-1areinvestigatedbyaquantumMonteCarlosimulationwiththeloop-clusteralgorithm.For1/2-1/2-1-1chain,wefindithastwophasesseparatedbyanenergy-gapvanishingpointintheground-state.For3/2-3/2-1-1chain,thenumericalresultsshowtwoenergy-gapvanishingpointsisolatedbydifferentphasesinitsground-state.Ourcalculationsindicatethatallthesegroundstatephasescanbeunderstoodbymeansofvalence-bond-solidpicture,andthethermodynamicbehavioratfinitetemperaturesiscontinuousasafunctionofparameterα=J2/J1.

  • 标签: 蒙特卡罗模拟 混合自旋链 铁磁性 基态 热力学性质 能隙
  • 简介:WeinvestigateindetailtheeffectsofR-parityleptonnumberviolationonthedecay~↑b1b~↑x1^0intheR-parityviolatingminimalsupersymmetricstandardmodel(Rp-MSSM)underthepresentexperimentalconstraintsonRpparameters.Inournumericalcalculationsweconsidertwocasesofinputparametersofthesquarkandsleptonsectors,MsquarkMslepton,forcomparison.TheresultsshowthattherelativeR-parityviolatingcorrectionisnotverysensitivetothemassofthelightestneutralino-0↑x1andthedegenerateR-parityviolatingcouplingparameterλ2′,butstronglydependsonMsquark,Mslepton,tanβandthedegenerateR-parityviolatingcouplingparameterλ1′.Therelativecorrectionisabout-4~3%andcanexceed-6%insomeregionofparameterspace.Therefore,preciseexperimentanalysesonthedecay~↑b1b~↑x1^0mayprovideaprobeoftheR-parityviolation.

  • 标签: R-奇偶效应 最小超不对称模型 质子 稳定性 重子数
  • 简介:摘要近期220kV系统中发生了几起液压开关线圈烧毁事故,对系统造成很大的危害,本文详细的讲解了实际运行中的一起液压开关线圈烧毁事故,并就事故进行了分析并提出了对策。

  • 标签: 液压开关 信号缸 烧毁