学科分类
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500 个结果
  • 简介:LetAbead×drealexpansivematrix.AnA-dilationParsevalframewaveletisafunctionψ∈L2(Rd),suchthattheset{|detA|n/2ψ(Ant-l):n∈Z,l∈Zd}formsaParsevalframeforL2(R~d).AmeasurablefunctionfiscalledanA-dilationParsevalframewaveletmultiplieriftheinverseFouriertransformoff■isanA-dilationParsevalframewaveletwheneverψisanA-dilationParsevalframewavelet,where■denotestheFouriertransformofψ.Inthispaper,theauthorscompletelycharacterizeallA-dilationParsevalframewaveletmultipliersforanyintegralexpansivematrixAwith|det(A)|=2.Asanapplication,thepath-connectivityofthesetofallA-dilationParsevalframewaveletswithaframeMRAinL2(Rd)isdiscussed.

  • 标签: 框架 小波 乘数 傅立叶逆变换 可测函数 傅立叶变换
  • 简介:.Thesingle2dilationorthogonalwaveletmultipliersinonedimensionalcaseandsingleA-dilation(whereAisanyexpansivematrixwithintegerentriesand|detA|=2)waveletmultipliersinhighdimensionalcasewerecompletelycharacterizedbytheWutamConsortium(1998)andZ.Y.Li,etal.(2010).Butthereexistnomoreresultsonorthogonalmultivariatewaveletmatrixmultiplierscorrespondingintegerexpansivedilationmatrixwiththeabsolutevalueofdeterminantnot2inL2(R2).Inthispaper,wechoose2I2=(2002)asthedilationmatrixandconsiderthe2I2-dilationorthogonalmultivariatewaveletY={y1,y2,y3},(whichiscalledadyadicbivariatewavelet)multipliers.Wecallthe3×3matrix-valuedfunctionA(s)=[fi,j(s)]3×3,wherefi,jaremeasurablefunctions,adyadicbivariatematrixFourierwaveletmultiplieriftheinverseFouriertransformofA(s)(cy1(s),cy2(s),cy3(s))?=(bg1(s),bg2(s),bg3(s))?isadyadicbivariatewaveletwhenever(y1,y2,y3)isanydyadicbivariatewavelet.Wegivesomeconditionsfordyadicmatrixbivariatewaveletmultipliers.TheresultsextendedthatofZ.Y.LiandX.L.Shi(2011).Asanapplication,weconstructsomeusefuldyadicbivariatewaveletsbyusingdyadicFouriermatrixwaveletmultipliersandusethemtoimagedenoising.

  • 标签: Multi-wavelets FOURIER multipliers image denoising.
  • 简介:Anonlinearparabolicsystemisderivedtodescribeincompressiblenuclearwaste-disposalcontaminationinporousmedia.Asequentialimplicittirne-steppingisdefined,inwhichthepressureandDarcyvelocityofthemixtureareapproximatedsimultaneouslybyamixedfiniteelementmethodandthebrine,radionuclidandheataretreatedbyacombinationofaGalerkinfiniteelementmethodandthemethodofcharacteristics.Optimal-orderconvergenceinL2isproved.Time-truncationerrorsofstandardproceduresarereducedbytimesteppingalongthecharacteristicsofthehyperbolicpartofthebrine,radionuclideandhealequalios,temporalandspatialerrorarelossenedbydirectcompulationofthevelocityinthemixedmethod,asopposedtodifferentiationofthepressure.

  • 标签: NONLINEAR PARABOLIC system mixed finite element
  • 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.

  • 标签: 近地小行星 飞行轨迹 地球 太阳 轨道运动 不稳定流形
  • 简介:Thispapercontainsadetailed,selfcontainedandmorestreamlinedproofofthel~2decouplingtheoremforhypersurfacesfromthepaperofBourgainandDemeterin2015.TheauthorshopethiswillserveasagoodwarmupforthereadersinterestedinunderstandingtheproofofVinogradov'smeanvaluetheoremfromthepaperofBourgain,DemeterandGuthin2015.

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  • 简介:NineteenL-N-2-hydroxyethylaminoacidsandL-N,N-bis(2-hydroxyethyl)aminoacidswerepreparedfromthereactionofchlorohydrinwithL-alanine,L-valine,L-leucine,L-isoleucine,L-phenylalanine,L-serine,L-thrcunine,L-glutamicacid,L-asparticacidandglycine.L-N,N,N’,N’-tetra(2-hydroxyethyl)cystinewaspreparedbythereactionofL-cystinewithchlorohydrin.

  • 标签: hydroxyethyl PHENYLALANINE LEUCINE GLYCINE tetra solubility
  • 简介:ConsiderL2-projectionuhofuton-degreefiniteelementspaceonone-dimensionaluniformgrids.TwodifferentclassesoftheorthogonalexpansioninanelementforconstructingasuperclosetofunctionuhareproposedandthensuperconvergenceforbothuhandDuhareproved.Whennisoddandnoboundaryconditionsareprescribed,thenuhisofsuperconvergenceatn+1orderGausspointsGn+1ineachelement.Whennisevenandfunctionvaluesontheboundaryareprescribed,thenuhisofsuperconvergenceatn+1orderpointsZn+1ineachelement.Iftheotherboundaryconditionsaregiven,thentheconclusionsarevalidinallelementsthatitsdistancefromtheboundary≥ch|lnh|.Theaboveconclusionsarealsovalid.forn-dergreerectangularelementQ1(n).

  • 标签: Superconvegence L~2-projection FINITE elements.
  • 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:We’llstudytheFEMforamodelforcompressiblemiscibledisplacementinporousmediawhichincludesmoleculardiffusionandmechanicaldispersioninone-dimensionalspace.Aclassofvertices-edges-elementsinterpolationoperatorinkisintroduced.Withthehelpofink(notellipticprojection),theoptimalerrorestimateinL∞(J;L2(Ω))normofFEMisproved.

  • 标签: Molecular diffusion and mechanical dispersion SINGLE-PHASE
  • 简介:SomecharacterizationsoftheconditionalexpectationoperatorsonLebesgue-BochnerspacesL_p(μ,X)aregiven,where1≤p<∞,p≠2.AlsoanexampleisgiventoshowthatthecharacterizationsoftheconditionalexpectationoperatorsonL_p(μ,X)aredifferentfromthatonL_p(μ)_zFinally,arepresentationoftheconstant-preservingcontractiveprojectiononspacesL_p(μ,X)isgotwhen0

  • 标签: preserving EXPECTATION OPERATORS Radon CONDITIONAL LEBESGUE
  • 简介:摘要刻画了|C(S)/L|≤2的完全正则半群S的同余格的具体特征,给出了具有上述性质的所有完全正则半群的分类.

  • 标签: 同余格 局部关系 分类
  • 简介:WeinvestigatethenonlinearSchrdingerequationiut+△u+|u|p-1u=0with1+4/N2)(whenN=1,2,1+4/N2>||Q||(1-sc)/sc|▽Q||2,theneitheru(t)blowsupinfiniteforwardtimeoru(t)existsgloballyforpositivetimeandthereexistsatimesequencetn→+∞suchthat||▽u(tn)||2→+∞.HereQisthegroundstatesolutionof—(1—sc)Q+△Q+|Q|p-1Q=0.Asimilarresultholdsfornegativetime.Thisextendtheresultofthe3DcubicSchr(o|¨)dingerequationobtainedbyHolmertothegeneralmass-supercriticalandenergy-subcriticalcase.

  • 标签: NLS方程 SCHRODINGER forward 发散 EXTEND cubic
  • 简介:在这份报纸,为在3D的不可压缩的海军司烧方程围住的nonhomogeneous或无界的领域的大答案的全球L2稳定性的问题被学习。由精细的精力估计并且在大解决方案的合适的条件下面,它证明如果起始的数据是已知的强壮的解决方案的那些上的小不安,大解决方案是稳定的。

  • 标签: 不可压缩NAVIER-STOKES方程 稳定性 非齐次 能量估计 无界域 非均匀
  • 简介:ThecommutatorsofsingularintegraloperatorswithhomogeneouskernelΩ(x)/|x|^narestudied,whereΩishomogeneousofdegreezero,andhasmeanvaluezeroontheunitsphere.ItisprovedthatΩ∈L(logL)^(k+1)(S^(n-1))isasufficientconditionsuchthatthek-thordercommutatorisboundedonL^2(R^n).

  • 标签: 转接器 单一积分算子 有界平均振动 傅里叶变换
  • 简介:TheternaryCu(Ⅱ)complexwith2,2′-bipyridyl(bipy)andL-methioninte(L-Met)hasbeensynthesizedandcharacterizedbyelementalanalysis,molarconductivity,UV-Visspectra,IRspectraandpH-potentiometrictitrationmethods.Thestructureofthecomplex[Cu(L-Met)(bipy)(H2O)]ClO4·3/8H2OwascharacterizedbytheX-raydiffractionanalysis.Itcrystallizesinthetriclinicsystem,spacegroupP1withfourmoleculesinaunitcellofdimensions,a=0.7656(2)nm,b=1.3142(3)nm,c=2.0596(4)nm,α=97.70(3)°,β=97.96(3)°,γ=94.33(3)°,V=2.0244(8)nm^3,R1=0.0441andwR2=0.0678,Thecrystalcontainsfourcrystallographicallyindependent[Cu(L-Met)(bipy)(H2O)]^+complexes(Cu1-Cu4),havingadistortedsquare-pyramidalgeometrywiththesamecoordinatedatomsaroundeachcoppercenter.Thebaseplaneisoccupiedbytwonitrogenatomsofonebipy,theaminonitrogenatomandonecarboxylateoxygenatomfromeachindependentL-Metmoiety,andonewateroxygenatanaxialposition.CulandCu3areessentiallyenantiomersofCu2andCu4.Thefourmoleculesarepackedwitheachotherbyintermolecularhydrogen-bondingandaromatic-ringstackinginteractions.

  • 标签: 铜(Ⅱ)配合物 2 2′-二吡啶 L-蛋氨酸 合成 分子结构 表征
  • 简介:TheLaboratoryforIntenseLasers(L2I)isaresearchcentreinopticsandlasersdedicatedtoexperimentalresearchinhighintensitylaserscienceandtechnologyandlaserplasmainteraction.Currentlythelaboratoryisundergoinganupgradewiththegoalofincreasingtheversatilityofthelasersystemsavailabletotheusers,aswellasincreasingthepulserepetitionrate.Inthispaperwereviewthecurrentstatusofthelaserresearchanddevelopmentprogrammeofthisfacility,namelytheupgradedcapabilityandtherecentprogresstowardstheinstallationofanultrashort,diode-pumpedOPCPAlasersystem.

  • 标签: DIODE-PUMPED SOLID-STATE LASER and APPLICATIONS FEMTOSECOND