简介：Thecopolymerizationsofethylenewith10-undecen-1-olhavebeeninvestigatedusingvanadiumprecatalysts,bis(imino)pyrrolylvanadium(III)complexes1-3,2,5-C4H2N(CH=NR)2VCl2(THF)2[R=C6H5(1),2,6-iPr2C6H3(2),C6F5(3)],andtheiminopyrrolylandβ-diketiminateonesforcomparison.Thepolarmonomerwaspretreatedbydiethylaluminiumchloride(presentalsoasthecocatalyst)beforethecopolymerization.ThemonomerreactivityratioswereevaluatedusingtheFineman-Rossmethod.Theligandstructureconsiderablyinfluencedthecatalyticactivityandtolerancetowardsthepolarmonomer,thepolarmonomerincorporationandthemolecularweightsoftheresultantcopolymers.Thebis(imino)pyrrolylvanadiumcomplexesexhibitedpromisingcatalyticperformanceforthecopolymerization,andahighcatalyticactivityupto3.84kg/mmolv·hwithahighcomonomerincorporationof14.0mol%wasachievedbycomplex3undermildconditions.

简介：Whenmeasurementsareperformedinhighspeed,small-scalecompressors,theuseofcurvedglasswindowsisrequiredinordertoavoidanymismatchbetweenthemeasurementwindowandthecasing.However,theglasscurvatureleadstoopticaldistortions,whichhinderacceptablemeasurementsandcanevenpreventtheacquisitionofanydata.Thus,anoriginalopticalassembly,whichconsistsininsertingasimpleandinexpensivecorrectivewindowbetweenthefrontallensoftheanemometerandtheshroudwindow,isproposed.Thewayofdeterminingthegeometriccharacteristicsandthepositionofthiscorrectivewindow,whichrestoresveryacceptablefoci,ispresentedinthepaper.Thereliabilityofthiscorrectiveopticalassemblyishighlightedbycomparativemeasurementsinatestcase.Usingsuchanopticalsetting,L2Fmeasurementswererealisedalongasection,downstreamoftheinletguidevane(IGV)ofatransoniccompressorstage.Thespatialresolutionleadstoagooddescriptionoftheinteractionofthewakewiththeobliqueshockemanatingfromtheleadingedgeoftherotor.Aphenomenologicalstudyofthewake/shockinteractionwithachangeofframeisrealisedusingthestreamwiseequationofthetransportofvorticity.

简介：N-acetyl-D-methionine,NaAcandtheremainsofN-acetyl-L-methioninedramaticallyaffectthepurificationofL-methioninewhenpurifiedfromthemixtureofenzymaticallydeacylatedN-acetyl-DL-methionine,leadingtoalowyieldconventionally.Here,thispaperreportsasuccessfulseparationandpurificationofbothL-methionineandN-acetyl-D-methioninebyanHion-exchangecolumn.ThepH,L-Metconcentrationandtheratiobetweenthecontentofsodiumcationandtheion-exchangecapacitywereoptimizedtoobtainthemaximumyield.Experimentalresultsindicatethat,undertheoptimizedconditions,theyieldsofL-methionineandN-acetyl-D-methioninecanreachashighas85%and75%,respectively.

简介：让(Y，d，dl)\left({\mathcal{Y}，d，d\lambda}\right)(n，|

简介：Tetrazole-1-aceticacidwasfoundtoserveasasuperiorligandforCuI-catalyzedN-arylationofimidazoleswitharyliodidesunderalowcatalystloading(5mol%ofCuI).AvarietyofaryliodidescouldbeaminatedtoprovidetheN-arylatedproductsingoodtoexcellentyieldswithouttheneedofaninertatmosphere.

简介：设Yi=x′iβ0+ei,i=1,…,n,为线性回归模型。此处x1,x2,…为已知p维向量。以βn记β0的L1估计,即设随机误差e1,e2,…独立,med（ei）=0,且存在正数l1,l2,使P（-h≤ei≤0）≤l1h≥P（0≤ei≤h）,0≤h≤l2,i=1,2,…则当时,βn不是β0的弱相合估计。

简介：建立了转移开覆盖的一个新的KyFan型匹配定理．作为应用，获得了Fan-Browder重合定理，不动点定理、极大元定理，相交定理和截口定理．

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简介：Highlyselectivedimerizationofα-methylstyrene(AMS)waseffectedusingaBroenstedacidicionicliquid,[Hmim]^+BF4^-,assolventaswellascatalyst,providingtheindustrialhigh-valueolefin,2,4-diphenyl-4-methyl-1-pentene(1-PT).Thedesireddimer1-PTcouldbeobtainedin90%yieldat96%conversioninthedimerizationofAMSunderoptimizedconditions.Featuresoftheprocedureincludeuseofreadilyavailableionicliquid-catalyst,exclusionofvolatileorganicsolvents,higherselectivityandefficiencyfor1-PT.

简介：DrivenbycuriosityaboutpossibleflightoptionsfortheChang’e-2spacecraftafteritremainsattheSun-EarthL2point,effectiveapproachesweredevelopedfordesigningpreliminaryfuel-optimalnear-Earthasteroidflybytrajectories.Theapproachesincludetheuseofmodifiedunstablemanifolds,gridsearchofthemanifolds’parameters,andatwo-impulsemaneuverfororbitalphasematchingandz-axisbiaschange,andaredemonstratedtobeeffectiveinasteroidtargetscreeningandtrajectoryoptimization.Asteroidflybysareexpectedtobewithinadistanceof2×107kmfromtheEarthowingtotheconstrainedEarth-spacecraftcommunicationrange.Inthiscase,thespacecraft’sorbitalmotionissignificantlyaffectedbythegravitiesofboththeSunandtheEarth,andtherefore,theconceptofthe"heliocentricoscillating-Keplerorbit"isproposed,becausetheclassicalorbitalelementsoftheflybytrajectoriesreferencedintheheliocentricinertialframeoscillatesignificantlywithrespecttotime.Theanalysisandresultspresentedinthisstudyshowthat,amongtheasteroidswhoseorbitsarethemostaccuratelypredicted,"Toutatis","2005NZ6",or"2010CL19"mightbeencounteredbyChang’e-2inlate2012or2013withtotalimpulseslessthan100m/s.

简介：利用Jensen不等式,Steklov变换,Cauchy积分主值讨论了一类离散指数型线性积分修正插值算子在Orlicz空间L*M(-∞,∞)中的逼近问题,给出了收敛速度的估计.

简介：讨论了B-值随机变量序列加权和的弱大数定律及Lr收敛性,同时获得了稳定P型Banach空间性质的刻画.

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简介：在现在的纸，我们声明有关为非卷绕旋转的一个类的pointwise集中和它的率的一些近似定理打形式的非线性的不可分的操作员：

简介：Four1,2,3-trisubstitutedimidazoliniumiodideswhichwereusedas5,10-+CPh-THFmodel（7-10）atformicacidoxidationlevelweresynthesized.Thebenzylidynegroup（phenyl-substitutedonecarbonunit）transferreactionsfromthesecompoundstoGrignardreagentwerein-vestigated,andthereactionsofthesecompoundswithKBH4andNaOHwerealsostudied.

简介：Aseriesofnovel1H-benzimidazol-1-ylacetatesand1H-benzimidazol-1-ylpropionatescontaining1H-1,2,4-triazolemoietyweresynthesizedundermicrowaveirradiationbymulti-stepreactions,inyieldsof87-94%.TheirinvitroantifungalactivitiesagainstBotrytiscinereaandSclerotiniasclerotiorumwereevaluatedbymycelialgrowthratemethod.AllthetargetcompoundsexhibithighactivitiesagainstB.cinereawiththeEC50valuesof7.96-21.74μg/mL,higherthanthatofcarbendazim.

简介：Poly(4-vinylpyridine)supportednanoparticleofcopper(Ⅰ)iodideisreportedasagreenandrecyclablecatalystfortheregioselectivesynthesisof1,4-disubstituted-1H-1,2,3-triazolesfrombenzylhalides,sodiumazideandterminalalkynesinwater.Thiscatalystcanberecoveredbysimplefiltrationandrecycledupto8consecutiverunswithoutanylossofitsefficiency.

简介：Novelsulfur-containingcompounds(3a–3c,4a–4c)wereobtainedinethanolwith1,3-diphenyl-2-propanoneasthestartingmaterial.Theadvantagesofthisprocedureweremildreactionconditions,simpleprotocol,andhighyields.ThestructuresoftheproductswerecharacterizedbyIR,1HNMR,MSandelementaryanalysis.Thecrystalofthenewcompound4abelongstomonoclinic,spacegroupC2witha=18.727(3),b=6.5179(9),c=13.7576(18),b=131.0610(10)°,V=1266.2(3)A3,Z=2,Dc=2.136g/cm3,μ=1.078mm-1,F(000)=843,R=0.0490andwR=0.1247for3211observedreflectionwithI>2δ(I).X-rayanalysisrevealsthatthemoleculeisnotsymmetrical,themolecularstructureisstabilizedbyweakp–pstackinginteractions,andnoclassicalhydrogenbondscanbeobserved.

简介：Sixnewopticallyactivepoly(amide-imide)s(5a-f)weresynthesizedthroughthedirectpolycondensationreactionofN,N'-(4,4'-diphthaloyl)-bis-L-leucine(3)withsixhydantoinderivatives(4a-f).Triphenylphosphite(TPP)/pyridineinthepresenceofcalciumchloride(CaCl_2)andN-methyl-2-pyrrolidone(NMP)weresuccessfullyappliedfordirectpolycondensation.Thepolycondensationreactionsproduceaseriesofnewpoly(amide-imide)s(5a-f)inhighyields,andinherentviscositybetween0.42and0.55dL/g.Theresultingpoly(amide-imide)s(5a-f)werecharacterizedbyelementalanalysis,viscositymeasurements,thermalgravimetricanalysis(TGAandDTG),solubilitytestandFT-IRspectroscopy.

简介：采用噻吩-2-甲醛分别与邻氨基苯硫酚和硫代氨基脲合成了2种噻吩-2-甲醛杂环席夫碱.利用红外光谱、紫外-可见光谱、荧光光谱、X-射线单晶衍射分析、热重分析和核磁共振氢谱等检测方法对2种目标新型杂环类席夫碱产物的结构和性质进行了表征与分析.采用量子化学中常用的密度泛函方法（DFT）对2种新席夫碱化合物进行几何优化,采用单激发组态相互作用（CIS）和含时密度泛函方法（TD-DFT）进一步优化,比较计算光谱与实际测试光谱之间的误差,探究了2种席夫碱化合物荧光发光机制,为这类席夫碱分子结构设计提供了理论依据.