简介:题目:一种多振子超声电机的设计目的:对超声电机而言,当多个压电振子并联时,由于以同一设计方案制作的电机振子往往具有不同的动态特性,因此会使得多振子电机的效率有所下降。即多振子电机工作的关键是如何使多个振子协同一致地驱动转子。为提高集成型多振子电机的效率和简化电机结构,提出一种构造贴片式多振子旋转超声电机的方法。创新点:1.提出圆周面内驱动的概念,发展已有的面内驱动概念(x-y面);2.提出一种模态转换方法,通过多个振子弯曲振动的叠加形成设计电机的扭转振动;3.电机工作时,不仅各个振子处于共振状态,而且连接而成的定子同样处于共振状态,有利于提高电机的效率;4.验证多振子同步驱动的机理。方法:1.振子采用贴片式结构,由极化方向沿厚度方向的压电陶瓷和金属基体粘结而成;与使用兰杰文振子相比,使用贴片式振子易于简化电机的结构。2.各个振子首尾相连形成电机的定子,既可用于构造直线电机,又可转换成旋转电机。3.通过有限元方法对不同振子数构成的电机定子进行性能比较,并且分析设计电机的驱动机理;此外,通过仿真分析确定电机的最优尺寸。4.根据设计结果,加工原理样机,并且对加工的样机进行实验研究,探讨设计方法的可行性。结论:1.根据仿真分析结果,最终加工的电机定子包含5个振子。2.定子中各个振子的振动特性完全相同,振子同步工作。3.样机定子的内径为28mm,外径为35mm,高为30min;测得定子的纵振和扭转频率分别为44.42kHz和43.83kHz;当激励电压的频率为43.9kHz、峰值为100V时,电机的空载转速为45r/min,堵转力矩为0.3N·m,最大效率约为30%。4.本文所设计的电机,是一种多振子并行驱动的整体式电机,具有结构紧凑和多�
简介:影响量chromodynamic(pQCD)分析的perturbative的一个主要问题是为使QCD联合跑的重正常化可伸缩以便为物理observables的最大地精确的改正顺序预言被获得的一个方法的缺乏。最大的Conformality(PMC)的原则消除与常规重正常化规模背景过程联系的歧义,产出独立于重正常化计划的选择的预言。联合规模和夸克风味的有效数字的QCD在pQCD系列被给order-by-order。PMC有一个稳固的理论基础,令人满意自我一致性条件的标准重正常化组不变性条件和所有源于重正常化组。在每份订单的PMC规模被转移联合经常的s消除非保角的所有的强壮的力量的参数获得{在pQCD系列的i}条款。{没有歧义,i}条款从重正常化组方程被决定。跑在每份订单并且在每个阶段空间点联合的正确行为然后能被获得。在NC的PMC还原剂0Abelian限制到Gell-Mann-Low方法。在这份简短报告,我们总结我们PMC的最近的申请的结果到很多个collider过程,强调这条途径的概论和适用性。hadronicZ腐烂的讨论证明由使用PMC,没有规模歧义,一个人能在每份订单为全部、分开的腐烂宽度完成精确预言。我们也看那一个人是否采用PMC在next-to-next-to-leading顺序水平决定最高夸克的对提交向后不对称现象,一个人为不对称现象的Tevatron大小获得全面、前後一致的pQCD解释。这说明D0合作为增加t\(\overlinet\)观察的减少增加的行为不变的质量。在更低的精力,重夸克的尖分布能被用来获得重夸克潜力的一颗直接决心。巨大的夸克和雷普顿的尖分布的讨论也被介绍,包括到电磁的形式因素的二环的修正的fermionic部件。这些结果证明PMC的申请系统地为pQCD预言消除主要理论无常,因此增加的collider敏感到远非标准模型所及的可能的新物理�
简介:Fabricationofmicrogratingsusingafemtosecondlaserexposuresystemisexperimentallyinvestigatedfortheelectronmoirémethod.Microholesandlinesarefirstlyetchedforparameterstudy.Gratingprofileistheoreticallyoptimizedtoformhighqualitymoirépatterns.Forademonstration,aparallelgratingisfabricatedonaspecimenofquartzglass.Theminimumlinewidthandthedistancebetweentwoadjacentlinesarebothsettobe1μm,andthefrequencyofgratingis500lines/mm.Theexperimentalresultsindicatethatthequalityofgratingsisgoodandtherelativeerrorofthegratingspitchisabout1.5%.Basedonmoirémethod,scanningelectronmicroscope(SEM)moirépatternsareobservedclearly,whichmanifeststhatgratingsfabricatedwiththefemtosecondlaserexposureissuitableformicroscaledeformationmeasurement.
简介:Thispaperstudiesscale-typestabilityforneuralnetworkswithunboundedtime-varyingdelaysandLipschitzcontinuousactivationfunctions.Severalsufficientconditionsfortheglobalexponentialstabilityandglobalasymptoticstabilityofsuchneuralnetworksontimescalesarederived.Thenewresultscanextendtheexistingrelevantstabilityresultsinthepreviousliteraturestocoversomegeneralneuralnetworks.
简介:Withthedevelopmentoflasertechnologies,multi-colorlight-fieldsynthesiswithcompleteamplitudeandphasecontrolwouldmakeitpossibletogeneratearbitraryopticalwaveforms.Apracticaloptimizationalgorithmisneededtogeneratesuchawaveforminordertocontrolstrong-fieldprocesses.Wereviewsomerecenttheoreticalworksoftheoptimizationofamplitudesandphasesofmulti-colorlaserstomodifythesingle-atomhigh-orderharmonicgenerationbasedongeneticalgorithm.Bychoosingdifferentfitnesscriteria,wedemonstratethat:(i)harmonicyieldscanbeenhancedby10to100times,(ii)harmoniccutoffenergycanbesubstantiallyextended,(iii)specificharmonicorderscanbeselectivelyenhanced,and(iv)singleattosecondpulsescanbeefficientlygenerated.Thepossibilityofoptimizingmacroscopicconditionsfortheimprovedphasematchingandlowdivergenceofhighharmonicsisalsodiscussed.Thewaveformcontrolandoptimizationareexpectedtobenewdriversforthenextwaveofbreakthroughinthestrong-fieldphysicsinthecomingyears.
简介:我们为解决三凸的可分离的功能的和的最小化建议了一个最初双的固定的点算法(PDFP),它与Lipschitz连续坡度,线性合成nonsmooth功能,和nonsmooth功能包含光滑的功能。与类似的工作相比,在PDFP的参数更容易选择并且在一个相对更大的范围被允许。我们将扩大PDFP解决二种可分离的多块最小化问题,在信号处理和成像科学产生。这个工作显示出把PDFP算法用于多块问题的灵活性并且说明实际、充分切开的计划怎么能被导出,特别为大规模问题的平行实现。连接和比较到轮流出现的方向方法(ADMM)更多样地也是现在。我们表明不同算法怎么能被通过稀少的经典例子以不同方法切开这些问题获得有限制的调整最不方形的模型。特别地,在多块ADMM的上下文为线性地抑制的问题,它具有伟人的一个班感兴趣,能被PDFP也与集中的一条保证解决。最后,一些实验被提供说明PDFP算法导出的几个计划的表演。
简介:High-pressureratioandwideoperatingrangearehighlyrequiredforaturbochargerindieselengines.Arecirculationflowtypecasingtreatmentiseffectiveforflowrangeenhancementofcentrifugalcompressors.Tworinggroovesonasuctionpipeandashroudcasingwallareconnectedbymeansofanannularpassageandstablerecirculationflowisformedatsmallflowratesfromthedownstreamgroovetowardtheupstreamgroovethroughtheannularbypass.Theshapeofbaselinerecirculationflowtypecasingismodifiedandoptimizedbyusingamulti-pointoptimizationcodewithametamodelassistedevolutionaryalgorithmembeddingacommercialCFDcodeCFXfromANSYS.Thenumericaloptimizationresultsgivetheoptimizeddesignofcasingwithimprovingadiabaticefficiencyinwideoperatingflowraterange.Sensitivityanalysisofdesignparametersasafunctionofefficiencyhasbeenperformed.Itisfoundthattheoptimizedcasingdesignprovidesoptimizedrecirculationflowrate,inwhichanincrementofentropyriseisminimizedatgroovesandpassagesoftherotatingimpeller.
简介:Forthemulti-frequencyacousticanalysis,aseriesexpansionmethodhasbeenintroducedtoreducethecomputationtimeofthefrequency-independentparts,buttheRungephenomenonwillarisewhenthismethodisemployedinhighfrequencyband.Therefore,thismethodisimprovedbyanalyzingtheapplicationconditionandproposingtheselectionprincipleoftheseriestruncationnumber.Theargumentintervalcanbeadjustedwiththewavenumberfactor.Therefore,theproblemofunstablenumerationandpoorprecisioncanbesolved,andtheapplicationscopeofthismethodisexpanded.Thenumericalexampleofacousticradiationshowsthattheimprovedmethodiscorrectforacousticanalysisinwiderfrequencybandwithlessseriestruncationnumberandcomputationamount.
简介:基于Si的多层的结构广泛地在当前的微电子学被使用。在他们的准备期间,一些不同类的剩余应力被导致,导致在接口错配和表面精力和平导致结构失败之间的竞争。这个工作在多层的半导体heterostructure在剩余应力的测量上介绍方法学的研究。扫描电子显微镜学(SEM),micro-Raman光谱学(太太),和传播电子显微镜学(TEM)被使用测量多层的结构的几何参数。在拉曼光谱和压力/紧张在上之间的关系[100]并且[110]水晶取向被决定分别地启用表面和剖面图剩余压力分析。基于印射结果的拉曼,沿着多层的heterostructure的深度的剩余应力的分发成功地被获得。
简介:题目:少量管冻结稳态温度场数学模型目的:少量任意布置冻结管冻结的稳态温度场无解析解。建立任意布置少量管冻结稳态温度场模型,获得解析解,解决人工冻结温度场理论问题。创新点:1.基于势函数叠加原理,确立人工地层冻结中少量管冻结稳态温度场的通用求解方法;2.建立任意布置的3根和4根非等温冻结管下冻结稳态温度场数学模型,获得其解析解通解及特解。方法:1.通过理论分析,将冻结管简化为热汇点源,确定人工地层冻结热势的拉普拉斯方程表述;2.应用势函数叠加原理建立少量管冻结稳态温度场的通用求解方法;3.建立少量管冻结稳态温度场的数学模型,通过理论推导获得温度场解析解;4.通过数值模拟,验证所提方法、数学模型和解析解的正确性和准确性。结论:1.将冻结管简化为点源(热汇),其冻结形成的热势场服从拉普拉斯方程,其解即为热势函数;2.多根冻结管冻结时,将单根冻结管的热势函数叠加,由冻结管的位置决定每根冻结管的热流,再根据边界条件定解。这一方法(即势函数叠加法)可以用于任意布置冻结管冻结稳态温度场解析解的求解:3.将冻结管简化为点源导致获得的解析解存在一定的误差,但误差仅发生在冻结管附近极小的范围内,并且误差微小,完全满足工程上的精度要求。
简介:Asystemofjointlytransferringtimesignalswitharateof1pulsepersecond(PPS)andfrequencysignalsof10MHzviaadensewavelengthdivisionmultiplex-based(DWDM)fiberisdemonstratedinthispaper.Thenoisesofthefiberlinksaresuppressedandcompensatedforbyacontrolledfiberdelayline.Amethodofcalibratingandcharacterizingtimeisdescribed.The1PPSissynchronizedbyfeed-forwardcalibratingthefiberdelaysprecisely.Thesystemisexperimentallyexaminedviaa110kmspooledfiberinlaboratory.Thefrequencystabilitiesoftheuserendwithcompensationare1.8×10-14at1sand2.0×10-17at104saveragetime.Thecalculateduncertaintyoftimesynchronizationis13.1ps,whereasthedirectmeasurementoftheuncertaintyis12ps.Next,thefrequencyand1PPSaretransferredviaametropolitanareaopticalfibernetworkfromonecentralsitetotworemotesiteswithdistancesof14kmand110km.Thefrequencystabilitiesof14kmlinkreach3.0×10-14averagedin1sand1.4×10-17in104srespectively;andthestabilitiesof110kmlinkare8.3×10-14and1.7×10-17,respectively.Theaccuraciesofsynchronizationareestimatedtobe12.3psforthe14kmlinkand13.1psforthe110kmlink,respectively.
简介:WeinvestigateinthispapertheinfluenceofslowlightonthebalancebetweentheKerrandtwo-photonabsorption(TPA)processesinsiliconslottedhybridnonlinearwaveguides.Threetypicalsiliconphotonicwaveguidegeometriesarestudiedtoestimatetheinfluenceofthelightslow-downfactoronthemodefieldoverlapwiththesiliconregion,aswellasonthecomplexeffectivenonlinearsusceptibility.Itisfoundthatslottedphotoniccrystalmodestendtofocalizeintheirhollowcorewithincreasinggroupindex(n_G)values.Consideringahybridintegrationofnonlinearpolymersinsuchslottedwaveguides,arelativedecreaseoftheTPAprocessbymorefactorof2ispredictedfromn_G=10ton_G=50.Asawhole,thisworkshowsthattherelativeinfluenceofTPAdecreasesforslottedwaveguidesoperatingintheslowlightregime,makingthemasuitableplatformforthird-ordernonlinearoptics.
简介:Wepresentadesignmethodforcalculatingandoptimizingsoundabsorptioncoefficientofmulti-layeredporousfibrousmetals(PFM)inthelowfrequencyrange.PFMissimplifiedasanequivalentidealizedsheetwithallmetallicfibersalignedinonedirectionanddistributedinperiodichexagonalpatterns.Weuseaphenomenologicalmodelintheliteraturetoinvestigatetheeffectsofporegeometricalparameters(fiberdiameterandgap)onsoundabsorptionperformance.ThesoundabsorptioncoefficientofmultilayeredPFMsiscalculatedusingimpedancetranslationtheorem.Todemonstratethevalidityofthepresentmodel,wecomparethepredictedresultswiththeexperimentaldata.Withtheaveragesoundabsorption(lowfrequencyrange)astheobjectivefunctionandthefibergapsasthedesignvariables,anoptimizationmethodformulti-layeredfibrousmetalsisproposed.Anewfibrouslayoutwithgivenporosityofmulti-layeredfibrousmetalsissuggestedtoachieveoptimallowfrequencysoundabsorption.Thesoundabsorptioncoefficientoftheoptimalmulti-layeredfibrousmetalishigherthanthesinglelayeredfibrousmetal,andasignificanteffectofthefibrousmaterialonsoundabsorptionisfoundduetothesurfaceporosityofthemulti-layeredfibrous.
简介:Theeffectofthefacethicknesstocoreheightratioondifferentmulti-layerpyramidalcoresandwichcolumnsunderin-planecompressionisinvestigatedtheoreticallyandnumerically.Numericalsimulationisingoodagreementwiththeory.Resultsindicatethatonespecifiedfacethicknesstocoreheightratiocorrespondstooneoptimumlayernumberofmulti-layerpyramidalcoresandwichcolumnsinconsiderationofengineeringapplication.Thisresultcanguidethesandwichstructuredesign.
简介:雷纳兹应力(RS)上的积极偏爱的效果和它在边血浆的光线的狂暴的运输上的效果(r/a?=?0.9)并且在tokamak的血浆的擦去层(太阳)区域被调查。光线并且poloidal电场(Er,Ep)和离子浸透电流(我s)被多种用途的探查(MPP)测量。这根探针在IR-T1tokamak第一次被制作并且构造。这根探针的大多数优点是Er和Ep能在单个射击在不同半径被测量。因此不同半径的信息能与高精确相比。偏爱电压在V偏爱?=?200V和它与在r/a被修理的limiter偏爱被使用了?=?0.9。而且,之间的阶段差别光线并且MPP检测的RS光谱的poloidal电场,和时间的进化被计算。边上的RS大小(r/a?=?0.9)多于它在太阳的价值(r/a?=?1.02)。与应用偏爱200V,RS和Er和Ep被增加,当光线的狂暴的运输同时被减少时。因此,RS影响光线的骚乱,这能被结束。RS光谱的时间的进化证明RS的频率在r/a被增加并且到达它的最高的价值?=?0.9面对偏爱。
简介:Thispaperdiscussesastatisticalsecond-ordertwo-scale(SSOTS)analysisandcomputationforaheatconductionproblemwitharadiationboundaryconditioninrandomporousmaterials.Firstly,themicroscopicconfigurationforthestructurewithrandomdistributionisbrieflycharacterized.Secondly,theSSOTSformulaeforcomputingtheheattransferproblemarederivedsuccessivelybymeansoftheconstructionwayforeachcell.Then,thestatisticalpredictionalgorithmbasedontheproposedtwo-scalemodelisdescribedindetail.Finally,somenumericalexperimentsareproposed,whichshowthattheSSOTSmethoddevelopedinthispaperiseffectiveforpredictingtheheattransferperformanceofporousmaterialsanddemonstratingitssignificantapplicationsinactualengineeringcomputation.