简介：(-)-(5R,6S)-6-Acetoxyhexadecan-5-olide1,anaturalmosquitoattractantpheromone,wassynthesizedfromreadilyavailablealdehyde2andcyclopentanone3usingL-proline-catalyzedasymmetricaldolreactionasthekeystep.

简介：Asimplemethodisappliedtocalculatingtheisotopeshifts(ISs)on5S1/2→4D3/2,5/2transitionsof87,88Sr+.FirstwehavecalculatedtheISsoflowertransitionsonaseriesofalkali-likesystemssuchasB2+,Ca+andBa+,whichareinagreementwithotherworks.ThentheISson5S1/2→4D3/2,5/2transitionsof87,88Sr+,whichareusefultostudytheSr+opticalfrequencystandard,areevaluated.

简介：ErdǒsandSósconjecturedin1963(see[1],Problem12in247)thateverygraphGonnverticeswithsizee(G)>1/2n(κ-1)containseverytreeTofsizek.Inthispaper,weprovetheconjectureforgraphswhosecomplementscontainnocyclesoflength4.

简介：Abstract.Inthispaperweshallinvestigatetheboundofstaxlikvnessrfortheclass

简介：Inthispaper,withPoincare’sformalism,andanindirectmethod,thecanonicalformsofthegeneralizedequationsofmotionduetoNielsenandCenovofaholonomicdynamicalsysteminthevelocity-phasespaceandtheacenleration-phasespaceareobtainedintermsofthePoincareparameters.

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简介：Weproveseveralinequaliesforsymmetricpostivesemidefinite,generalMmatricesandinverseM-matriceswhicharegeneralizationoftheclassicalOppenheim'sInequalityforsymmetricpositivesemidefinitematrices.

简介：TheextendedcanonicalNoetheridentitiesandcanonicalfirstNoethertheoremderivedfromanextendedactioninphasespaceforasystemwithasingularLagrangianareformulated.UsingthesecanonicalNoetheridentities,itcanbeshownthattheconstraintmultipliersconnectedwiththefirst-classconstraintsmaynotbeindependent,soaquerytoaconjectureofDiracispresented.BasedonthesymmetrypropertiesoftheconstrainedHamiltoniansysteminphasespace,acounterexampletoaconjectureofDiracisgiventoshowthatDirac'sconjecturefailsinsuchasystem.WepresenthereadifferentwayratherthanCawley'sexamplesandother'sonesinthatthereisnolinearizationofconstraintsintheproblem.Thisexamplehasafeaturethatneithertheprimaryfirst-classconstraintsnorsecondaryfirst-classconstraintsaregeneratorsofthegaugetransformation.

简介：设S是幺半群含有零元0≠1,且S-系为S0-Act中的对象,本文引进伪投射S-系,刻划了伪投射S-系的一些性质和特征.

简介：ItisprovedthattheChebyshevpolynomial_n(x)=T_n(xcosπ/2n),hasthegreatestuniformnormon[-1,1]ofitsthirdderivativeamongtherealpolynomialsofdegreeatmostn,whichareboundedby1in[-1,1]andvanishin-1and1.

简介：当减肥遇见聚会．模特遭遇PARTY．美女与饕餮相逢……美丽的身材与美味之间将如何选择，心里盘算着永无止境的加减乘除．还是有第二条出路，如果丢掉肚脯上的赘肉．便意味着牺牲生命中的乐趣吗？你将永远拒绝朋友的聚会．或者在宴会上永远用眼睛享用美食？

简介：In1972,Fullerprovedthatacompleteadditivesubeategory_RCofR-Modisequivalenttoamodulecategory⊿-Modifandonlyif_RC=Gen(_RU)forsomequasiprogenerator_RUand⊿≌End_RUcanonically.Inthisnotetheauthorgivesacharacterizationof_RCwhichmakes_RUaprojectiveR-moduleinthecasewhenRisarightperfectringwithidentity,andshowsthatR-ModistheuniquecompleteadditivesubcategoryofR-ModwhichisequivalenttoR-ModforaleftArtinianringR.

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简介：ForagraphG,P(G,λ)denotesthechromaticpolynomialofG.TwographsGandHaresaidtobechromaticallyequivalent,denotedbyG-H,ifP(G,λ)=p(H,λ).Let[G]={H|H-G}.If[G]={G},thenGissaidtobechromaticallyunique.Foracomplete5-partitegraphGwith5nvertices,defineθ(G)=(a(G,6)-2^n+1-2^n-1+5)/2n-2,wherea(G,6)denotesthenumberof6-independentpartitionsofG.Inthispaper,theauthorsshowthatθ(G)≥0anddetermineallgraphswithθ(G)=0,1,2,5/2,7/2,4,17/4.Byusingtheseresultsthechromaticityof5-partitegraphsoftheformG-Swithθ(G)=0,1,2,5/2,7/2,4,17/4isinvestigated,whereSisasetofedgesofG.Manynewchromaticallyunique5-partitegraphsareobtained.

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简介：Thesynthesisof(S)-2-(3-arylacrylamido)-3-{4-[2-(5-methyl-2-phenyloxazol-4-yl)ethoxy]phenyl}propanoicacidsisdescribed.TheirstructureswereconfirmedbyH-NMR.

简介：把自己比喻成一种动物，是什么？为什么？答：性感的蜘蛛，跟我现在怀孕的身材比较搭调。

简介：InthispaperwegiveanalmostsharperrorestimateofHalley’siterationforthemajorizingsequence.Comparedwiththecorrespondingresultsin[6,14],itisfarbetter.Meanwhile,theconvergencetheoremisestablished.forHalley’siterationinBanachspaces.

简介：<正>InthepresentnotethealgebraicindependenceofvaluesofseveralMahlerserieswithcertainparticularanddifferentparametersatalgebraicpointsisestablishedbymeansofatypicalapproximationmethodhandlingtheLiouvilletypeseries.

简介：InthispaperwediscusstheconvergenceofamodifiedNewton’smethodpresentedbyA.Ostrowski[1]andJ.F.Traub[2],whichhasquadraticconvergenceorderbutreducesoneevaluationofthederivativeateverytwostepscomparedwithNewton’smethod.Aconvergencetheoremisestablishedbyusingaweakconditiona≤3-2(21/2)andasharperrorestimateisgivenabouttheiterativesequence.