学科分类
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500 个结果
  • 简介:Carbazole-basedbi-functionalphotorefractivepolyacrylateswerepreparedviafreeradicalpolymerizationandpost-azo-couplingreaction.ThestructureofpolymerswascharacterizedbyFouriertransforminfraredspectroscopy(FTIR)andprotonnuclearmagneticresonance(1H-NMR)spectroscopy.Thedifferentialscanningcalorimetry(DSC)andthethermalgravimetricanalysis(TGA)wereusedtocharacterizethethermalpropertyofpolymers.Theresultsindicatethatthoughtheglasstransitiontemperature(Tg)ofpolymersincreaseswithincreasingtheratioofNLOgroups,thepolymerswithdifferentratiosofNLOgroupsstillallshowlowglasstransitiontemperaturesaround60°C,andgoodthermalstability,whicharefavorabletothepracticalapplicationofthesepolymers.Thegelpermeationchromatographic(GPC)resultindicatesthatthesepolymersallhavehigh-molecular-weightwhichisfavorabletothelongtermstabilityofthematerial.Further,thesepolymershavegoodsolubilityinchloroformsolvent,andthesolutionscaneasilybefabricatedintoopticallytransparentfilms.Gaincoefficientsof75cm-1,185cm-1and66cm-1canbeobservedatzeroexternalelectricfieldwithoutanyadditionagentorpre-polingforpolymersP-2,P-3andP-4respectively.ThedifferentcontentsofNLOgroupsresultinthedifferentpropertiesofpolymersP-2,P-3andP-4.

  • 标签: 光折变聚合物 玻璃化转变温度 高分子量 双功能 表征 傅立叶变换红外光谱
  • 简介:Ba0.85Ca0.15Ti0.9Zr0.1O3(BCTZ)lead-freepiezoelectricceramicsco-dopedwithCeO2(x=0.1wt.%,0.2wt.%,0.3wt.%,0.4wt.%,0.5wt.%)andLi2CO3(0.6wt.%)werepreparedbyconventionalsolid-statereactionmethod.InfluenceofCeO2dopingamountonthepiezoelectricproperties,dielectricproperties,phasecompositionandmicrostructureofpreparedBCTZlead-freepiezoelectricceramicsdopedwithLi2CO3wereinvestigatedbyX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM)andotheranalyticalmethods.TheresultsshowedthatthesinteredtemperatureofBCTZlead-freepiezoelectricceramicsdopedwithCeO2decreasedgreatlywhenLi2CO3dopingamountwas0.6wt.%;apureperovskitestructureofBCTZlead-freepiezoelectricceramicsco-dopedwithLi2CO3andCeO2andsinteredat1050°Ccouldalsobeobtained.Thepiezoelectricconstant(d33),therelativepermittivity(εr)andtheplanarelectromechanicalcouplingfactor(kp)ofBCTZceramicsdopedwithLi2CO3increasedfirstlyandthendecreased,thedielectricloss(tanδ)decreasedfirstlyandthenincreasedanddecreasedatlastwhenCeO2dopingamountincreased.TheinfluenceofCeO2dopingonthepropertiesofBCTZlead-freepiezoelectricceramicsdopedwithLi2CO3werecausedby'softeffect'and'hardeffect'piezoelectricadditiveandcausinglatticedistortion.WhenCeO2dopingamount(x)was0.2wt.%,theBCTZceramicsdopedwithLi2CO3(0.6wt.%)andsinteredat1050°Cpossessedthebestpiezoelectricpropertyanddielectricpropertywithd33of436pC/N,kpof48.3%,εrof3650,tanδof1.5%.

  • 标签: 无铅压电陶瓷 陶瓷性能 低温烧结 掺杂量 氧化铈 扫描电子显微镜
  • 简介:Chalcopyrite-typeCuInSe2nanoparticlesaresuccessfullypreparedbyusingIn2Se3nanoparticlesasaprecursorreactedwithcopperchloride(CuCl)solutionviaaphasetransformationprocessinlowtemperature.Thereactiontimeisakeyparameter.Afterthereactiontimeincreasingfrom0.5hto8h,In2Se3andCuClreactwitheachothergraduallyviaphasetransformationintoCuInSe2withoutanyintermediatephase.ThecrystallinestructureandmorphologyoftheCuInSe2nanoparticlesarecharacterizedbyX-raydiffraction(XRD)andfieldemissionscanningelectronmicroscopy(FESEM).ThediameterofCuInSe2nanoparticleswithgooddispersibilityrangesfrom10nmto20nm.ThebandgapoftheCuInSe2nanoparticlesis1.04eVcalculatedfromtheultraviolet-visible(UV-VIS)spectrum.

  • 标签: CulnSe2 纳米颗粒 相变过程 场发射扫描电子显微镜 化学过程 低温
  • 简介:Weproposeageneralmethodologytodefinetheoptimumdopingionvolumedistributionrequiredforanefficientsolid-statelaseramplifier.ThisapproachisillustratedinthecontextoftwoexperimentaldiodepumpedYb:YAGamplifiersoperatingat300and160K.Processingofsuchtailoredgainmediaisnowpossiblethroughhorizontaldirectcrystallization.

  • 标签: diode SOLID-STATE LASER LASER GAIN medium
  • 简介:Low这个词……真是,算是目前最流行的最有力的用来鄙视别人的词了吧。和过去不一样的是,你想看不起谁,无论是他的穿衣打扮、言行举止,还是他为人处世方面,都不用再费心地去想什么侮辱性贬损性词汇,只要摇摇头,冷淡地说一句“他太low了”,立刻体内会分泌一种高大上的物质,让自己感觉好到不得了,俨然上帝视角俯视了一下世界,特别恨铁不成钢。

  • 标签: 言行举止 为人处世
  • 简介:Oxygenisotopefractionationbetweencoexistingmineralsinslowlycooledrocksconveysinformationabouttheircoolinghistory.Byusingthefastgrainboundary(FGB)modeltosimulateclosed-systemdiffusiveexchangeofoxygenisotopesbetweencoexistingminerals,Ishowthattheapparentequilibriumtemperatures(Tae)bythemineralpairwiththelargestisotopicfractionation(PLIF)alwaysliesbetweentheclosuretemperatures(Tc)ofthosetwominerals.Therefore,whentherateofoxygendiffusionandhenceTcforthePLIFchancetobecomparable(suchasinthecaseofquartzandmagnetite),TaewillserveasagoodapproximationofTcregardlessofvariationinmineralproportions.ThespecialtyofthePLIFinconstrainingTaewithintheirTcrangecanbegeneralizedtootherstableisotopesystemsandelementpartitioning.ByapproximatingTcwithTaeandinvertingDodson'sequation,thecoolingrateofplutonicormetamorphicrockscanbeinferred.

  • 标签: 氧同位素分馏 封闭温度 平衡温度 表观 共生矿物 冷却速率
  • 简介:<正>Polyhalite(K2SO4·MgSO4·2CaSO4·2H2O)isoneoftheinsolublepotassiummineralwhichiswidelydistributedinsulfate-typepotassium-bearingdeposit,andthetheoreticalconcentrationofK2SO4is28%.Itcanbedirectlyusedasa

  • 标签: POLYHALITE potassium-rich BRINE LEACHING calcium CHLORIDE
  • 简介:Strainageinginsteelwasfirstobservedduringthe19thcenturywhenthemaximumloadcarryingcapacityofatestpiecewasincreasedafterithadbeenretestedfollowingapreviousseriesoftestinginaplasticrange.Overthelastdecades,agreatdealofresearchhasbeenperformedtogaindeeperinsightsintothephenomenonofstrainageing.Thesynergisticdevelopmentoftheoreticalhypothesisandnewexperimentalevidenceshaspromotedtheunderstandingofthemechanismsunderlyingstrainageing.Thecontentofthispaperisorganizedintofourcomponents.First,wehavecomparedthemaintheoriesdevelopedinrecentyears.Second,wehavesummarizedthemetallurgicaleffectsonthestrainageingbehaviorobservedinexperiments.Moreover,wehavemadeanattempttocorrelatetheexperimentalresultsandtheabove-mentionedtheories.Third,wehaveproposedafeasiblesolutiontocontrolstrainageinginlowcarbonsteels.Finally,wehaveelaboratedthepotentialityoftheatomprobetechniqueinfacilitatingdirectcharacterizationofthedistributionofsoluteatoms.

  • 标签: 应变时效 低碳钢 实验证据 溶质原子 承载试验 最大负荷
  • 简介:消费者们对容易腐烂的食物的质量给予越来越多的注意,它被存储温度主要影响。这份报纸在温度控制下面为容易腐烂的食物论述一个动态定价模型。为了最大化全部的利润,最佳的价格和存储,温度用Pontryagins最大的原则被获得。一个静态的定价模型被提供与动态的作比较。它被动态政策能比静态的使更多的收入成为的一个数字例子显示出。而且,经理的含意被分析,建议方法的有效性被表明。

  • 标签: 易腐食品 温度控制 动态定价 储存温度 定价模式 最大值原理
  • 简介:ForthereliabilityandpowerconsumptionissuesofEthernetdatatransmissionbasedonthefieldprogrammablegatearray(FPGA),alow-powerconsumptiondesignmethodisproposed,whichissuitableforFPGAimplementation.Toreducethedynamicpowerconsumptionofintegratedcircuit(IC)design,theproposedmethodadoptsthedynamiccontroloftheclockfrequency.Formostofthetime,whentheportisintheidlestateorlower-ratestate,userscanreduceoreventurnoffthereadingclockfrequencyandreducetheclockflipfrequencyinordertoreducethedynamicpowerconsumption.Whenthereceivingrateishigh,thereadingclockfrequencywillbeimprovedtimelytoensurethatnodatawilllost.SimulatedandverifiedbyModelsim,theproposedmethodcandynamicallycontroltheclockfrequency,includingthedynamicswitchingofhigh-speedandlow-speedclockfliprates,orstopoftheclockflip.

  • 标签: 低功耗设计 数据传输 以太网 现场可编程门阵列 MODELSIM FPGA实现
  • 简介:Thispaperinvestigatestheinfluenceoflow-carbonpoliciesonchannelcoordinationforatwo-echelonsupplychainconsistingofonesupplierandoneretailer.Fourdifferentmodelsareconsidered:thebasicmodel,thecarbonemissionmodel,thecarbonemissiontradingmodelandthecarbontaxmodel.Wefindthatthegovernmentpolicyonallcarbonemissionmodelsisnotuniversalamongthefirmsaswellasthecustomers.Thecarbonemissiontradingpolicyisalwaysbetterthanthecarbonemissionpolicyandthecarbontaxpolicywhentheallocatedcarbonemissionquotasaregreaterthanthecarbonemissions.Thecarbonemissiontradingpolicyisprovedtobeaneffectivemechanismwhichcanmotivatethesupplychaintoreducecarbonemissions.Undercertainconditions,thesupplychainprefersthecarbonemissiontradingpolicywithhighercarbonpricetootherpolicies.IntheframeworkofStackelberggamewiththesupplierastheleader,foreachcarbonpolicy,thepaperpresentscoordinationmechanismwiththeall-unitwholesalequantitydiscountcontract(AWQD).Weanalyzeandcomparetheinfluenceoflow-carbonpoliciesonchannelcoordinationforthefourlow-carbonpolicies.Numericalexperimentsareconductedtoexamineourfindings.

  • 标签: 供应链 低碳 STACKELBERG博弈 排放交易 排放模型 碳排放
  • 简介:影响司烧混合的层温度变化上的飘移被考虑Stokes飘移在混合的层温度并且用的方程导致的一个移流的热运输学期估计海洋并且从一个全球海洋发行量模型(HYCOM)和一个波浪的波浪参数当模特儿(波浪手表III)。维的分析和量的评价方法被进行估计Stokes飘移导致的效果的重要性并且分析它的空间分发和季节的变化特征。到在mid-to-high纬度的混合的层温度变化的Stokes飘移的贡献与吝啬的水流的是可比较的结果表演,和混合的层温度变化的实质的部分被考虑Stokes飘移效果导致。尽管Stokes飘移导致的移流热运输不是为混合的层温度方程的领先的术语,它不能被忽视并且甚至为upperocean温度的模拟在一些区域变得批评。

  • 标签: 温度变化 海洋环流 数值估算 上层 定量预测方法 季节变化特征
  • 简介:Inthisstudy,weexaminedtheeffectofelevatedtemperatureontheexpressionpatternsofgenes,i.e.,nacrein,irr,n16,n19,andhsp70inthepearloysterPinctadafucata.Theexperimentwascarriedoutat4temperatures,i.e.,20℃(ambient,control),24,28℃,and32℃.TheexpressionlevelsoftargetgenesinP.fucatawereassayedat0,6,24,48,and96hviareal-timepolymerasechainreaction.Resultsshowedthattheexpressionlevelsofnacreinandirrhadnosignificantvariationsamongdifferenttimepointsbelow28℃,butsignificantlyincreasedovertimeat32℃.Theexpressionlevelsofn16andn19didnotchangemarkedlyat20℃.Theformerincreasedsignificantlyat6hand24hwhilethelattersubstantiallydecreasedduring6–96hat24,28and32℃.Amongdifferenttemperatures,thelevelofn16wassignificantlylowerat20℃thanatothertemperaturesduring6–96h,andthelevelofn19significantlyvariedamongdifferenttemperaturesat48hand96h.Theexpressionlevelofhsp70wassignificantlyhigherat32℃thanat20,24and28℃at24h.TheseresultsdemonstratedthatelevatedtemperatureimpactedthephysiologicalprocessesofP.fucataandpotentiallyinfluenceditsadaptabilitytothermalstress.

  • 标签: 合浦珠母贝 基因表达 温度 热休克蛋白70 聚合酶链反应 HSP70
  • 简介:Basedontheanalysisontheglobalwarmingandenvironmentaldeterioration,low-carbonconcepthasreceivedmoreandmoreattentionfromgovernments,expertsandscholarsathomeandabroad.TheBritishgovernmentfirstputforwardtheconceptoflow-carboneconomy,andafterthattheJapanesegovernmentproposedtheconstructionoflow-carbonsociety.Inourcountry,expertsandscholarsbegantoresearchonlow-carboncityfrom2007.Thispaperlooksthroughthepracticalandtheoreticalstudiesonlow-carboncityconstructionofthedomesticexpertsandscholars.Thecurrentbackgroundoflowcarboncityconstructionisfirstintroduced.Toclarifyfundamentalconnotation,characteristicsandtargetofChina’slow-carboncityisveryimportant.Therefore,thispapersummarizestheresearchprogressofthelow-carboncityconstructionfromthenecessity,theconnotationandcharacteristicsoftarget.Then,weshouldpayattentiontochoosingtherightindex,combiningtheregioncharacteristicswiththecurrentdevelopmentmodelandevaluationindexessystem,toreflectandimprovecarbonemissions.Finally,thepapergivesanoverviewofsuggestionsbyexpertsandscholarsontheconstructionoflowcarboncity.

  • 标签: low-carbon ECONOMY low-carbon CITY CARBON EMISSION