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186 个结果
  • 简介:Inthispapertheexistenceandstabilityofthepositiveequilibriumofthesize-structuredpopulationmodelareprovedbyRabinowitz'stheoremandthelocallinearizationmethod.Theresulthereshowsthatnearthebifurcationpointwhereabranchofpositiveequilibriaappears,thestabilityofthepositiveequilibriumonthebranchisdcpendentonthedirectionofthebifurcation.Theargumentforthemodelofage-structuredpopulationisgeneralizedinthispaper.

  • 标签: 整体模型 系统建模 平衡方程 线性化方法 分岔 稳定性
  • 简介:Numerousexperimentalevidencesshowthatthegrainsizemaysignificantlyaltertheyieldstrengthofmetals.Similarly,in-strengthenednickel-basedsuperalloys,theprecipitatesizealsoinfluencestheiryieldstrength.Then,howtodescribesuchtwokindsofsizeeffectsontheyieldstrengthisaverypracticalchallenge.Inthisstudy,accordingtoexperimentalobservations,acollinearmicro-shear-bandsmodelisproposedtoexplorethesesizeeffectsonmetalmaterials’yieldstrength.Ananalyticalsolutionforthesimplemodelisderived.Itrevealsthattheyieldstrengthisafunctionofaveragegrain-sizeorprecipitate-size,whichisabletoreasonablyexplainsizeeffectsonyieldstrength.Thetypicalexamplevalidationshowsthatthenewrelationshipisnotonlyabletopreciselydescribethegrain-sizeeffectinsomecases,butalsoabletotheoreticallyaddresstheunexplainedHall-Petchrelationshipbetweentheγprecipitatesizeandtheyieldstrengthofnickel-basedsuperalloys.

  • 标签: COLLINEAR micro-shear-bands MODEL The HALL-PETCH relationship
  • 简介:Foranasymmetricmatrix,thezero-nonzeropatternPofentriescanbedescribedbyadigraphΓ(P)whichhasanarcifanentryisnonzero.Theminimumrankofazero-nonzeropatternisdefinedtobethesmallestpossiblerankoverallrealmatriceshavingthegivenzero-nonzeropattern.Definitionsofvariousgraphparametersthathavebeenusedtoboundminimumrankofazerononzeropattern,includingpathcovernumberandeditdistance,andthetrianglesizetri(P).Inthispaper,byconvertingadigraphintoanundirectedbipartitegraphG(U,V),wepresentanalgorithmforconstructingasub-bipartitegraphwiththeuniquemaximumperfectmatchingM',andobtainthattri(P)=|M'|forP.

  • 标签: Zero-Nonzero Pattern TRIANGLE SIZE BIPARTITE GRAPH
  • 简介:Thispapercontributestoextractinginformationfromsignalsofbroadbandultrasonicattenuationspectrumforeffectiveutilizationinparticlesizecharacterization.Thesingleparticlescatteringmodelandthecoupled-phasemodelareformulatedsimultaneously,therelationshipbetweenparticlesizedistributionandultrasonicspectrumisestablished,andaconvergencecriterionforcalculationisquantified.Demonstrationinversionbytheoptimumregularizationfactormethodiscarriedouttoyieldtypicalnumericalresultsfordiscussion.Withtheexperimentalset-updevelopedbytheInstituteofParticleandTwo-PhaseFlowMeasurement(IPTFM)attheUniversityofShanghaiforScienceandTechnology,sandsedimentparticlesizeismeasuredbyattenuationspectrumandanalyzedusingtheaboveinversionalgorithmandtheoreticalmodels.Tovalidatetheproposedultrasonicspectrumparticlesizingmethod,resultsarecomparedwiththoseobtainedbymicroscopy.

  • 标签: ULTRASONIC SPECTRUM PARTICLE SIZE INVERSION
  • 简介:<正>1IntroductionAnhydroussodium,mainlyproducedintheUnitedStates,Canada,Japan,isindispensablecommoditiesandrawmaterialsindailylifeandindustry.Inrecentyears,anhydroussodiumsulfateofgeneralsizewasmuchoversupplied[1].Howeverparticlesanhydroussodiumsulphateoflargesizeisnotadequatetothedemandforits

  • 标签: Additive Sodium sulphate Crystallization Crystal SIZE
  • 简介:这篇论文介绍一个测量过程,叫了RmFFP,它为建模描述一套操作并且用OO方法需求模型从高级说明估计面向对象的软件系统的尺寸。OO方法是一个自动软件生产方法。这个工作的贡献是系统地定义允许在软件生产过程的一个早阶段估计功能的尺寸的一套规则,根据COSMIC-FFP。做这,我们描述为软件测量跟随一个过程模型的步骤的建议测量过程的设计,应用程序,和分析。我们也以它的重制度在RmFFP的评估上报导起始的结果。电子增补材料这篇文章(doi:10.1007/s11390-007-9050-6)的联机版本contatins增补材料,它对授权用户可得到。

  • 标签: 需求规则 软件开发过程 泛函尺寸 测量技术
  • 简介:Inthispaperamodeloftransvcrsalfilterispresentedtostudytheadaptivematchofthetimevariantchannel.Theleastmeansquareerrorfil-teringmethodisusedtoobtaintheweightingcoeffcientsofthefilter.Withthepurposeofspeedinguptheconvergenceoftheiterationequationofadaptivefiltering,anadaptivefactoroftheiterationstepsizeμ_aisderivedinthispaper.Theresultofcomputersimulationshowsthatinthecaseofusingadaptiveμ_a,theconvergencespeedoftheiterationequationisincreased2timesapproximatelyincomparisonwithconstantμ_f.Thestudysuggeststhattheadaptivefilterwithadaptiveμ_a.havetheperformancetofollowthechangeoftime-variantcharacteristicsofthechannel.

  • 标签: ITERATION MATCH FILTERING weighting CORRECTION instead
  • 简介:无数生物因素被建议了解释早泄(PE)。然而,有精囊(SV)的数据相关PE是稀少的。学习试图评估在SV和PE的尺寸之间的关系。没有PE,代表性的学习与PE和44个志愿者包括了44个门诊病人,并且SV的尺寸被比较。射精的潜伏时间,早泄诊断工具(PEDT),可勃起的Function-15的国际索引,和健康长期的前列腺炎症状的国家研究所索引的自我估计的intravaginal被用于对症状的评价。比作控制组,PE组有SV的显著地更高的吝啬的前面以后的直径(APD)(P<0.001)。SV截止水平的最佳的吝啬的APD是为PE的9.25公里。在PE组,PEDT与SV的吝啬的APD相比与SV9.25公里的吝啬的APD也是更高的<9.25公里。PEDT显著地与SV的吝啬的APD被相关(r=0.326,P=0.031)。精液的血浆蛋白质被集体spectrometry在六PE和六个匹配的控制盒子之间比较,102蛋白质是至少起来调整或下面调整的1.5褶层,这被显示出。在他们之中,GGT1,LAMC1,和应用软件在PE组是显著地更高的。这些结果显示有SV的更大的吝啬的APD的人可能让更高的PEDT得分。SV的Transrectal超声应该与早泄在病人的评估被考虑。SV可能在SV是为有PE和超声变化的病人的治疗的一个潜在的目标。

  • 标签: 超声检查 DIAMETER PEDT 慢性前列腺炎 SVS APD
  • 简介:Inphasefieldfracturemodelsthevalueoftheorderparameterdistinguishesbetweenbrokenandundamagedmaterial.Atcrackfacestheorderparameterinterpolatessmoothlybetweenthesetwostatesofthematerial,whichcanberegardedasphases.Thecrackevolutionfollowsimplicitlyfromthetimeintegrationofanevolutionequationoftheorderparameter,whichiscoupledtothemechanicalfieldequations.Amongotherphenomenaphasefieldfracturemodelsareabletoreproducecracknucleationininitiallysoundmaterials.Fora1Dsettingithasbeenshownthatcracknucleationistriggeredbythelossofstabilityoftheunfractured,spatiallyhomogeneoussolution,andthatthestabilitypointdependsonthesizeoftheconsideredstructure.Thisworknumericallyinvestigatestowhichextendsizeeffectsarereproducedbythe2Dphasefieldmodel.Exemplarily,afiniteelementstudyoftheholesizeeffectisperformedandthesimulationresultsarecomparedtoexperimentaldata.

  • 标签: 相场模型 规模效应 模型模拟 骨折 尺寸效应 演化方程
  • 简介:Effectsofthreegapswhicharelarge(118m2),medium(86m2)andsmall(20m2),respectively,andundercanopyofTsugalongibracteataforestontheseedlingestablishmentofT.longibracteatawerestudiedthroughseedburialexperimentsfromDecember2003toJanuary2005inTianbaoyanNationalNatureReserveofFujian,China.TheresultsshowedthattheareaofgaphadanevidenteffectontheseedlingestablishmentofT.longibracteata.TheseedlingemergenceratesofT.longibracteatainplotsoflargegap,mediumgap,smallgapandundercanopywere10%,10%,4%and6%,representinganincreasingtrendalongwiththegapsizeincreasingwithoutasignificantdifference.Rainerodingandinsectsfeedingweretwomainfactorsleadingtoseedlingdeath.Thelargerthegapsizewas,themoreseedlingswerekilledbyrainerosionandthefewerseedlingswerekilledbyinsectsfeeding.Theemergencetimeofseedlingswasalmostsameinallplotswhiletheirdeathtimewasdifferentrespectively.Thegapsizehadasignificantimpactonseedlingsurvivalrate.Theseedlingsurvivalratewashighestinthemediumgapplot(27.0%)andnexttothehighestinlargegapplot(7.3%),andseedlinginsmallgapplotandundercanopyplotdiedoutafteronegrowingseason.Increasedlightsupplyingapswasfavorablefortheseedlingsgrowthandsurvival.IncreasedlightsupplyinthelargegapcouldenhancethegrowthofseedlingleafandrootofT.longibracteata,andtheseedlinginturnallocatedmoredrymasstorootandleaf,butithaslittleimpactonthegrowthofstem.ThisresearchindicatesthatT.longibracteataisapioneerspeciesanditsseedlingestablishmentneedamediumorlargegap(>50m2).

  • 标签: 长苞铁杉 护顶 幼苗 生长特性
  • 简介:Abidispersegranularmixtureinaslightlytiltedcompartmentalizedchamberisexperimentallyfoundtoshowsizesegregationwhenverticallyvibrated.Asurfaceslopedevelopsandlargeparticlescongregatetothelowerside.Particlesrightupontheuppertipofthedividingwallbehaveinacompetitiveway,i.e.,theycangotoeithercompartmentdependingontheforceexertedonthem.

  • 标签: 尺寸分离 颗粒物质 垂直振动 粒子聚集 粒子动力学 粒子混合物
  • 简介:A。Kaneko和K。Ota证明了那为一最低限度地(n,λ)连接了图G,如果|G|=p≥3n-1,然后e(G)≤nλ(|G|-n);并且如果e(G)=nλ(|G|-n),当时,G对图K_同形(n,p-n)从完全的由两部组成的图K_被获得的~λ(n,p-n)由用λ代替每个边多重边;如果3n-1≥|G|≥n+1,然后e(G)≤λ(|G|+n)~2/8。在这篇论文,我们决定所有最低限度地(n,λ)与顺序p和最大的尺寸λ(p+n连接了图)为3n-1≥p≥n+的~2/81为3n-1≥p≥n+1。

  • 标签: 连通性 最小连接图 同构图 图论