学科分类
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9 个结果
  • 简介:Inthisarticle,wemainlydiscusstheasymptoticbehaviorformulti-dimensionalcontinuous-timerandomwalkinrandomenvironmentwithholdingtimes.Byconstructingarenewalstructureandusingthepoint'environmentviewedfromtheparticle',underGeneralKalikow'sCondition,weshowthelawoflargenumbers(LLN)andcentrallimittheorem(CLT)fortheescapespeedofrandomwalk.

  • 标签: 时间随机环境 随机游动 渐近性质 保温 中心极限定理 渐近行为
  • 简介:Developinganelectrostaticdischarge(ESD)protectiondevicewithabetterlatch-upimmunityhasbeenachallengingissueforthenanometercomplementarymetal-oxidesemiconductor(CMOS)technology.Inthiswork,animprovedgrounded-gateN-channelmetal-oxidesemiconductor(GGNMOS)transistortriggeredsilicon-controlledrectifier(SCR)structure,namedGGSCR,isproposedforhighholdingvoltageESDprotectionapplications.TheGGSCRdemonstratesadoublesnapbackbehaviorasaresultofprogressivetrigger-onoftheGGNMOSandSCR.Thedoublesnapbackmakestheholdingvoltageincreasefrom3.43Vto6.25Vascomparedwiththeconventionallow-voltageSCR.TheTCADsimulationsarecarriedouttoverifythemodesofoperationofthedevice.

  • 标签: GGNMOS ESD保护 维持电压 连续触发 SCR 互补金属氧化物半导体
  • 简介:Becauseofthedistinctionofsoilpropertyandhumuscontent,soilwatercontentisnotidealtoindicatewhetheritissuitabletothegrowthofplant.MainlybasedonthePF-anumericalvaluedenotingthewaterregimeofsoilandconnectedwiththegrowthofplant,thestudycombinedthemoisturepercentageofsoilwithPFtoresearchinquantitytheinterrelationbetweenthemoisturepercentageandPFindifferentsuccessionphasesofsubalpinedarkconiferousforestinGonggaMountain.Theresultsshowedthat:(1)InthesamePFvalue,themoisturepercentageinhumushorizonincreasedgraduallywiththedevelopmentofthesuccessionofthedarkconiferousforest;Themoisturepercentageofover-matureforestwasthehighestand>matureforest>half-matureforest>younggrowthforest;(2)Withtheincreaseofsoildepth,thesoilbulkdensityincreasedandthemoisturepercentagedecreased,butthedifferenceinthepercentageofmoisturewasnotnotableindifferentsuccessionphases.(3)Indifferentsuccessionseries,thevegetationaffectedthesoilwatercharacteristicsbyincreasingthesoilorganicmatter,improvingthesoilconstruction,recedingthesoilbulkdensityandenhancingthesoilporosity;(4)Thehumushorizonofthedarkconiferousforestsoilhasthehighestwaterholdingcapabilityinthisregion.

  • 标签: 贡嘎山地区 亚高山 暗针叶林 土壤持水作用 土壤含水率 土壤物理特性
  • 简介:Theeffectsofconcurrentpulsesinholdingdurationonsuperplasticityof2091Al-Lialloyhavebeeninvestigatedinthispaper.Theresultsofsuperplasticdeformationshowedthatconcurrentpulsesinholdingdurationdecreasedtheoptimumholdingtimeforsuperplasticdeformation(ε=3.33×10-2s,T=500℃)from15to5minandincreasedelongation(δ)from530to550%.Themetallographicobservationsshowedthatthespecimensappliedlybyconcurrentpulsewerecom-pletelyrecrystallizedafterholding5minat500℃,andgrainsrefinedtoabout2μm,andthosespec-imensunappliedcurrentpulseswerepartlyrecrystallizedevenafterholding15minat500℃.theelectronprobeanalysesindicatedthatconcurrentpulsespromotedatomicdiffusion.Itispointedoutthatconcurrentpulsesaccelerateatomdiffusionanddislocationmotion.increasenucleationrateofrecrystallizationanddecreasetheoptimumholdingtimeforsuperplasticdeformationandincreasesuperplasticproperties.

  • 标签: current PULSE SUPERPLASTICITY RECRYSTALLIZATION
  • 简介:Thispaperstudiesatwostagesupplychainwithadominantupstreampartner.ManufactureristhedominantpartnerandoperatesinaJust-in-Timeenvironment.Productionisdoneinasinglemanufacturinglinecapableofproducingtwoproductswithoutstoppingtheproductionforswitchingfromoneproducttotheother.Themanufacturerimposesconstraintsonthedistributorbyadheringtohisfavorableproductionschedulewhichminimizeshismanufacturingcost.Distributorontheotherhandcaterstoretailers'orderswithoutincurringanyshortagesandisresponsibleformanagingtheinventoryoffinishedgoods.Adheringtomanufacturer'sschedulemayleadtohighinventorycarryingcostsforthedistributor.Distributor'sproblem,whichistofindanoptimaldistributionsequencewhichminimizesthedistributor'sinventorycostundertheconstraintimposedbythemanufacturerisprovedNP-HardbyManojetal.(2008).Therefore,solvinglargesizeproblemsrequireefficientheuristics.Wedevelopalgorithmsforthedistributionproblembyexploitingitsstructuralproperties.Weproposetwoheuristicsandusetheirsolutionsintheinitialpopulationofageneticalgorithmtoarriveatsolutionswithanaveragedeviationoflessthan3.5%fromtheoptimalsolutionforpracticalsizeproblems.

  • 标签: 库存成本 合作伙伴 生产成本 供应链 上游 序列
  • 简介:ThediffusionbondingofAZ3\BMgalloyandQ235steelwasinvestigatedwithaZn-5AIalloyasinterlayerandunderdifferentholdingtimerangingfrom3to1200s.Themicrostructureandphasecompositionsofbondedjointswerecharacterizedbyscanningelectronmicroscopy(SEM),energydispersivespectrometer(EDS)andX-raydiffraction(XRD)methods.TheshearstrengthofMgalloy/steeljointswasmeasuredbytensiletester.Itwasfoundthatthemicrostructureofbondedjointsevolveddramaticallyalongwiththeprolongationofholdingtime.Undertheholdingtimeof3s,themainpartofjointwascomposedofMgZn2phaseanddispersedAl-richsolidsolutionparticles.Whenincreasedtheholdingtimemorethan60s,theexcessivesolutionofAZ3\Bintotheinterfacialreactionarealedtotheformationofcoarsephaseandeutecticmicrostructure,andalsothecomplexFe-AlandMg-Al-ZnIMCsattransitionlayerclosedtoQ235steelside.Accordingtothetensiletestingcharacterizations,thejointsobtainedunderholdingtimeof3sexhibitedthebestshearstrengthof84MPa,andthefractureoccurredattheintermediarypartofjointwheretheflexibleAl-richsolidsolutionparticlescouldhelptoimpedethemicrocrackpropagations.Withprolongingtheholdingtimeto600s,theshearstrengthofjointswasdeterioratedenormouslyandthefracturepositionwasshiftedtothetransitionlayerpartclosedtoQ235steel.

  • 标签: diffusion BONDING MICROSTRUCTURE SHEAR strength transition