简介：为了在impellers压制成穴并且做涡轮泵，更长生活，inducer与主要impeller被分开，两impellers独立地被驾驶。在impellers附近的泵和流动条件的表演试验性地被调查，下列结果被获得。(1)主要impeller贡献在inducer和主要impeller之间的流动相互作用。(2)两impellers的旋转速度能独立地被控制以便同时总体上压制成穴不仅impeller，而且在inducer。

简介：Thispaperdevelopsaunifiedmethodologyforareal-timespeedcontrolofbrushlessdirect-currentmotordrivesystemsinthepresenceofmeasurementnoiseandloadtorquedisturbance.First,themathematicalmodelandhardwarestructureofsystemisestablished.Next,anoptimalstatefeedbackcontrollerusingtheKalmanfilterstateestimationtechniqueisderived.Thisisfollowedbyanadaptivecontrolalgorithmtocompensatefortheeffectsofnoiseanddisturbance.Thosetwoalgorithmsworkingtogethercanprovideavery-high-speedregulationanddynamicresponseoverawiderangeofoperatingconditions.Simulatedresponsesarepresentedtohighlighttheeffectivenessoftheproposedcontrolstrategy.

简介：Thispaperstudiestheinteractionofshockandgradientwave(soundwave)ofsolutionstothesystemofinviscidisentropicgasdynamicsasamodelforthecorrespondingproblemsfornonlinearhyperbolicsystems.Theproblemcanbereducedtoaboundaryvalueprobleminawedgeddormain,ByusingthemethodofconstructingasymptoticsolutionsandNewton'siterationprocessitisprovedthatifaweakshockhitsagradientwave,thenthegrandientwavewillsplitintotwogradientwaves,whiletheshockcontinusespropagating.Inthispapertheauthorreducestheproblemtoastandardformandconstructsasymptoticsolutionoftheproblem.Theexistenceofthegenuinesolutionwillhegiveninthefollowingpaper.

简介：Theauthorintroducesanotionofweak1sequencesandcharacterizessuchsequencesbymeansofhomologicalmethods.ThisnotionextendsthenotionofweekM-sequencesandthusextendsthenotionsofgeneralizedCohen-MacaulaymodulesandBuchsbaummodulestomoregeneralcases.

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简介：ThemultivariatesplineswhichwerefirstpresentedbydeBooorasacompletetheoreticalsystemhaveintriguedmanymathematicianswhohavedevotedmanyworksinthisfieldwhichisstillintheprocessofdevelopment.Theauthorofthispaperisinterestedintheareaofinter-polationwithspecialemphasisontheinterpolationmethodsandtheirapproximationorders.ButsuchB-splines(bothunivariateandmultivariate)donotinterpolateddirectly,soIap-proachedthisprobleminanotherwaywhichistoextendmyinterpolatingsplineofdegree2n-1inunivariatecase(See[7])tomultivariatecase.Iselectedtriangulatedregionwhichisinspiredbyothermathematicians’works(e.g.[2]and[3])andextendtheinterpolatingpolynomialsfromunivariatetom-variatecase(See[10])Inthispapersomeresultsinthecasem=2arediscussedandprovedinmoreconcretedetails.Basedonthesepolynomials,theinterpolatingsplines(itisdefinedbymeaspiecewisepolynomialsinwhichtheunknownpar-tialderivativesaredeterminedundercertaincontinuousconditions)arealsodiscussed.Theapproximationordersofinterpolatingpolynomialsandofcubicinterpolatingsplinesareinverstigated.Welunitedourdiscussionontherectangulardomainwhichispartitionedintoequalrighttriangles.Astothecaseinwhichtherectangulardomainispartitionedintounequalrighttrianglesaswellasthecaseofmorecomplicateddomains,wewilldiscussinthenextpa-per.

简介：Hightimeresolutionmeasurementsoftheelectrostaticfluctuations,radialelectricfieldErandturbulence-inducedelectronfluxΓehavebeenperformedacrossthetransitionoflowerhybridcurrentdriveimprovedconfinementwithagraphiteLangmuirprobearrayatthelastclosedfluxsurfaceoftheHT-7tokamak.ThedecreaseofΓeisdominatedbythesuppressionoffluctuationlevels,whichfollowsthechangeofEr.AreversalofthepoloidalpropagationdirectionofturbulencedemonstratesthatthepoloidalpropagationisdominatedbyEr×Bφdrift.Theenhancementofpoloidalcoherenceaccompaniesthefluctuationsuppression,whichsuggeststhesubtlevariationofturbulencefeatures.

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简介：TheauthorsconsiderthemultilinearoscillatorysingularintegraloperatordefinedbyTA1,A2,…,Akf(x)=∫R^ne^ip(x,v)k/∏/j=1Rmi(Ajix,y)(Ω(x-y))/(│x-y│^n+M)f(y)dy,whereP(x,y)isareal-valuedpolynomialonR^n×R^n,Ωishomogeneousofdegreezero,Rmj(Aj;x,y)denotesthemj-thorderTaylorseriesremainderofAjatxexpandedabouty,M=k/∑j=1mj,ItisshownthatifΩbelongstothespaceLlog^+L(S^n-1)andhasvanishingmomentuptoorderM,then‖TA1,A2,…,Akf‖q≤ck/∏/j=1(∏/│α│=mj‖D^αAj‖rj)‖f‖p,providedthat1

简介：1．运用实例分析，认识运动的物体能够做功，所具有的能量称为动能．2．通过探究实验，知道动能的大小与物体的质量和运动速度有关．能运用动能与质量、速度的关系解释简单的生活现象．

简介：Reductionofmodulatorenergyconsumptionto10fJ∕bitisessentialforthesustainabledevelopmentofcommunicationsystems.Lumpedmodulatorsmightbeaviablesolutionifinstructedbyacompletetheorysystem.Here,wepresentacompleteanalyticalelectro-opticresponsetheory,energyconsumptionanalysis,andeyediagramsonabsolutescalesforlumpedmodulators.Consequentlythespeedlimitationisunderstoodandalleviatedbysingle-driveconfiguration,andcomprehensiveknowledgeintotheenergydependenceonstructuralparameterssignificantlyreducesenergyconsumption.Theresultsshowthatsiliconmodulationenergyaslowas80.8and21.5fJ∕bitcanbeachievedat28Gbdunder50and10Ωimpedancedrivers,respectively.A50Gbdmodulationisalsoshowntobepossible.Theanalyticalmodelscanbeextendedtolumpedmodulatorsonothermaterialplatformsandofferapromisingsolutiontothecurrentchallengesofmodulationenergyreduction.

简介：Weproposeapositionsensorlesscontrolschemeforafour-switch,three-phasebrushlessDCmotordrive,basedonthezerocrossingpointdetectionofphaseback-EMFvoltagesusingnewlydefinederrorfunctions(EFs).Thecommutationin-stantsare30°afterdetectedzerocrossingpointsoftheEFs.DevelopedEFshavegreatermagnituderatherthanphaseorlinevoltagessothatthesensorlesscontrolcanworkatalowerspeedrange.Moreover,EFshavesmoothtransitionsaroundzerovoltagelevelthatreducesthecommutationerrors.EFsarederivedfromthefilteredterminalvoltagesvaoandvbooftwolow-passfilters,whichareusedtoeliminatehighfrequencynoisesforcalculationoftheaverageterminalvoltages.Thefeasibilityoftheproposedsensorlesscontrolisdemonstratedbysimulationandexperimentalresults.

简介：让G是为一套素数的一个可分离的组，让N是G的正常亚群，并且让是我特性(即，无法缩减的部分特性)N。我们为G的我特性的数字获得一个必要、足够的条件在上拿可能的最大的|G:N||G:N|

简介：令人满意的概括我收缩或I-nonexpansive类型调节的军士muting自我地图的新班的普通的固定的点结果被建立。我们使用他们获得统一，延长，并且补充著名结果的几不变的近似结果。

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简介：主要引进了伪i-内射半模的定义,并根据对偶原则,参照k-投射半模及内射模的结论,得到了伪i-内射半模的一些很好的性质,从而实现了把环中内射模的某些性质在半环中内射半模方面的部分推广.

简介：Carbonnanotubeswithjunctionsmayplayanimportantroleinfuturenanoelectronicsandfuturenanodevices.Inparticular,junctionsconstructedwithmetalandsemiconductingnanotubeshavepotentialapplications.Basedontheorthogonaltight-bindingmoleculardynamicsmethod,wepresentourstudyofthestructurestabilityofI-typecarbonnanotubejunctions.

简介：用非线性分析的方法讨论了方程N（t）=N（t）[a（t）-∑ni=1bi(t)Ni(t-τi（t）)]的周期正解的存在性，所获结果包含或推广了已有的几上结论[2，3]。

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