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394 个结果
  • 简介:Theheattransferfromanelectricallyheatedcylinder(wire)offinitelengthtothesurroundingfluidcanbedividedintoheatradiation,conductionandconvection.Atechnicalapplicationofthesecylinderswithtypicaldimensionsof1-2mmlengthandafewmicrometersdiameteristheHot-Wire-Anemometry.Thissystematicstudyshouldclarifytheinfluenceoffreeconvectiontothreedimensionalheattransferofcylinders.forthisaimitisplannedtoinvestigateReynoldsnumbersbelowRe=1(creepingflow).Forthisreasonmeasurementsshouldbedoneunder1gintheearthlaboratoryandalsoundermicrogravity(μg)conditions.Comparisonsofthesemeasurementsunderotherwisesameconditionsallowstodistinguishbetweenthepureconvectionheattransferandthecontributionsduetoconductionandothereffects.FormeasurementsunderμgtheDropTowerBremencanbeusedasresearchfacility.DuetothefastresponseofconvectiontochangesinthegravityconditionstheDropTowerisanidealandcostefficientexperimentaltool.Theexperimentalsetupisbuildtooperateatvelocityrangeof0-1m/swhichincludesthewholerangeofconvectionfrompurefreeconvectionat0m/sovermixedconvectionuptopureforcedconvectionatvelocitiesaboveabout0.15m/s.ThisvelocityregioncorrespondstoarangeoftheReynoldsnumberofRe=0-0.18foracylinderof5μmdiameteratTf=140℃inairatanambienttemperatureofabout21℃.

  • 标签: 热传导 自由对流 效应研究
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  • 简介:Thedynamiccharacteristicsofthelargescalecoherentstructuresinaforcedfreeshearlayerareexperi-mentallystudiedbymeansofflowvisualization.ThequantitativemeasurementsareacquiredbytheuseofaLDV.Itisshownthatthedevelopmentofthecoherentstructurescanbegreatlyinfluencedbyupstreamartificialperturbationsandasaresultthemixinginthelayercanbecontrolled.Likevortexmerging,vortexsplittingisalsoacommonevolu-tionpatterninthedevelopmentofthecoherentstructures.

  • 标签: large scale COHERENT structure VORTEX MERGING
  • 简介:没有羡慕的定价问题能作为发现每个消费者在被分配的一个定价和分配计划在定价下面最大化其用途的一套项目被说。目标是最大化卖主收入。我们与作为在项目上定义的一个独立系统被给的一般供应限制学习这个问题。例如,限制能是很多线性限制或matroids。这捕获项目不在资源的限制下面在项目的消费者估价的思考先存在,但是被生产的状况。这份报纸集中于单位要求消费者的盒子。在背景,有n消费者和m项目;每个项目可以在多重拷贝被生产。每消费者i[n]在他/她感兴趣的集合S对i在条款j上有估价vij。他/她必须被分配(如果任何)给最大值的一个项目(非否定)用途。假定我们为发现最大的重量独立人士为给定的独立系统设定被给近似神谕(或稍微更强壮的神谕);为很多自然、有趣的供应限制,经常的近似算法是可得到的。我们获得下列结果。1)O(木头n)为一般盒子的近似。2)O(k)近似每个消费者什么时候至多对感兴趣k项目的不同类型。3)O(f)近似条款的每种类型什么时候至多对有趣f消费者。笔记期末考试甚至没有独立系统限制,二结果以前是未知的。

  • 标签: 消费者 定价 供给 自由 单位 分配方案
  • 简介:AccordingtoXinhuaNet,startingfrom2011,InnerMongoliaAutonomousRegionwillprovidefreeeducationandtextbookstoallthestudentsstudyingingeneralMongoliansecondaryschoolsandsecondaryvocationalschools,andfinanciallydisadvantagedstudentswhoarelearningingeneralChinesesecondaryschools.By2013,thepracticeswillcoverallsecondaryschoolstudentsinalldistricts,sofreeeducationfor

  • 标签: 内蒙古自治区 中学生 免费 教育 中等职业学校 新华网
  • 简介:Fluorineinmoldpowderisknownasharmfultohumanhealthandtheenvironment.Beingtheadvocateofgreenproduction,Baosteeldevelopedanenvironmentallyfriendlymoldpowderwithoutfluorine.Themainproblemoffluorine-freefluxfilmissmallheatresistanceandthustheheattransferintensityofthemoldistoolarge,whichtosomeextenthinderstheincreaseofthecastingspeed.Withtheheatflowsimulationequipment,controllingprecipitationofcrystalinfluxandsolidificationtemperatureproperly,fluorine-freemoldpowderforlowcarbonsteel,whichsubstitutesFwithB2O3,wassuccessfullydevelopedandappliedinindustrialproduction.Theproductionresultsshowthat,byusingboronicfluorine-freemoldpowder,theboronincrementinmoltensteelislessthan1.3ppmforconventionalaluminiumkilledlowcarbonsteel.

  • 标签: 结晶器保护渣 无氟保护渣 低碳钢 开发 应用 绿色生产
  • 简介:ThispaperprovidesareviewonsampleinjectorswhichareprovidedatSPring-8AngstromCompactfreeelectronLAser(SACLA)forconductingserialmeasurementina‘diffract-before-destroy'schemeusinganx-rayfreeelectronlaser(XFEL).VersatileexperimentalplatformsatSACLAareabletoacceptvarioustypesofinjectors,amongwhichliquidjet,dropletandviscouscarrierinjectorsarefrequentlyutilized.Theseinjectorsproducedifferentformsoffluidtargetssuchasaliquidfilamentwithadiameterintheorderofmicrometer,micro-dropletsynchronizedtoXFELpulses,andslowlyflowingcolumnofhighlyviscousfluidwitharatebelow1μLmin-1.Characteristicsandapplicationsoftheinjectorsaredescribed.

  • 标签: SACLA 样品注射者连续剧 femtosecond 晶体学 X 光免费电子激光
  • 简介:ThispaperdealswiththeapproximatesolutionoftheFredholmequationLu=fofthesecondkindwithf∈H’(Γ).First,wegivetheorderofthen-theoptimalradiusintheworstcasesetting.Then,weshowthattheGalerkinmethodusing2n+1innerproductsoffhasminimalerror.Finally,wegivetheestimateoftheε-complexityoftheFredholmproblemofthesecondkindandGalerkinmethodintheworstcasesetting.

  • 标签: Worst case COMPLEXITY FREDHOLM EQUATION GALERKIN
  • 简介:在这封信,空间光(FSO)用有图案的调整和桶察觉的通讯被介绍在复杂、吵闹的环境改进位错误率(BER)性能。散布的光在这通讯结构被平均。秒顺序关联,小浪正规化,并且察觉到压缩在重建算法被联合。有N位的一个信号从大部分被重建很好不到N大小。没有光过滤器在传统的FSO通讯使用了的narrowband,数字模拟和实验被执行。它能也在安全通讯被要求的真实网络被采用。这提供大机会为FSO通讯的真实应用铺平道路。

  • 标签: 自由空间光通信 检测 调制 图形 比特错误率 光学滤波器
  • 简介:Araucariaangustifolia(Bertol.)O.Kuntzeexhibitsdimorphisminitsstemstructure,wherethetrunkisorthotropicandbranchesandbranchlets(primaryandsecondarybranches)areplagiotropic.Thesestemsexhibitdifferentbehaviorwhenusedforvegetativepropagation,andonlysegmentsoftrunkcanformacompleteplant.Thephysiologicalandbiochemicalmechanismsthatcharacterizethesestemsarestilllittleknown.Theaimofthisstudywastodescribethefreeaminoacidprofilesintrunks,branches,andbranchletsofA.angustifolia.Segmentsof5cminlengthwereexcisedfromyoungindividualsbelowthestemapex.Theneedleswereremovedandsampleswerefrozenandlyophilized.Thedeterminationsweremadebyhigh-performanceliquidchromatography,andtheresultswereexpressedaslg/gfreshweight(FW).Thetrunksandbrancheshadthehighestcontentoftotalaminoacids,whichwere112.23±20.57lg/gFWand111.97±27.78lg/gFW,respectively.Theaminoacids—glutamine,aspartateandc-aminobutyricacidandtyrosine—werenoticeablyhigherinthethreetypesofstems.Inthetrunk,ahigheramountofasparagineandtryptophan,wasalsodetected.Glutamicacidandglutaminewerefoundinhigherquantitiesinthebranches.Thebranchletshadverylowtotalaminoacidcontent(30.79±4.19lg/gFW),whereinasparagineistheonlyaminoacidnotdetected.Thus,itwasobservedthattheprofileofthefreeaminoaciddiffersamongtrunks,branches,andbranchletsinA.angustifolia,indicatingthattheyperformdifferentfunctions.

  • 标签: BRAZILIAN PINE Physiological mechanisms Stem’s DIMORPHISM
  • 简介:州空间的方法被采用评估形式的参数机能上地分级,magneto-electro-elastic,和multilayered盘子。基于机能上地分级的材料的性质是指数的假设,作为州的变量拿结构的排水量和压力的结构的颤动的州的方程被导出。自然频率和形式的形状基于在这篇论文给的州的方程和边界条件的一般答案被计算。有弹性的排水量上的机能上地分级的指数的因素的影响,电,并且结构的磁场被与不同的叠假定一个三明治板模型讨论序列。

  • 标签: 功能等级材料 磁电弹性板 态空间 固体力学
  • 简介:免费生活的海洋的线虫的五种是redescribed并且在中国的黄海说明同样新的记录。这些种类包括一monhysterid,在家庭Diplopeltidae的Campylaimusgerlachi和四enoplids在家庭Oxystominidae的种类,Oxystominaelongata,Oxystominaelegans,Halalaimuslutarus和Halalaimuswodjanizkii。生态、分类的讲话与原来的描述比较被提供并且讨论。类Campylaimus的所有已知的种的关键被给。我们的调查结果离开犯错到benthic生态学和生物多样性的线虫的分类信息黄海学习。

  • 标签: 黄海 海生线虫 海洋生物 形态特征
  • 简介:Financialcrisis-thedrivetointegrationofregionaleconomiesTwosalientfeaturesareillustratedintoday'sglobaleconomypattern,whichis,economicglobalizationandtheintegrationofregionaleconomies.Theintegrationofregionaleconomiesstimulatestheglobalization,whileontheotherhandintegratingcountriesthataregeographicallycloseaimstofightagainstthenegativeimpactfromglobalization,includingthefinancialcrisis.

  • 标签: 东盟自由贸易区 中国 增益 区域合作
  • 简介:Inholographicencryption,doublerandom-phaseencodingintheFresneldomain(DRPEiFD)isaprevalentencryptionmethodbecauseitislenslessandsecure.However,noisesbringadverseeffectsduringdecryption.Inthisletter,weintroducequick-response(QR)codingduringencryptiontoresistnoises.WetransformtheoriginalinformationintoaQRcodeandthenencryptthecodeasahologramthroughDRPEiFD.Toretrievetheinput,wedecryptthehologramintheoppositemannertotheencryptionandsubsequentlyobtainaQRcodewithnoises.Byscanningthiscodewithproperapplicationsinsmartphones,wecanobtainanoise-freeretrieval.Numericalexperimentsandimagesscannedbyasmartphoneareshowntovalidateourproposedmethod.

  • 标签: 加密方法 快速响应 全息图 抗噪音 安全 双随机相位编码
  • 简介:Certificatelessencryptionattractsalotofattentionsofarbyeliminatingthekeyescrowprobleminidentity-basedencryptionandpublickeycertificatesinthetraditionalpublickeycryptography.Byconsideringthethreatfromthekeyexposure,itisdesirabletoincorporatetheideaofkey-insulatedcryptosystemintothecertificatelessencryption.Inthispaper,wehavedesignedanefficientcertificatelesskeyinsulatedencryption(CL-KIE)schemetoachievethisgoal.Byourapproach,thecomputationalperformanceofourschemehasbeenimprovedsignificantlyintermsofreductiononrunningtimeandstorage.WealsogavethesecurityproofofthenewCL-KIEschemeagainstthechosenplaintextattacks(CPAs)intherandomoracle,consideringtheassumptionofthecomputationalDiffie-Hellman(CDH)problem.

  • 标签: CERTIFICATELESS cryptography keyinsulated pairing-free random oracle
  • 简介:AbstractBackground:Deregulation of miRNA-21 expression has been reported to be associated with vascular smooth muscle behavior and cytoskeletal stability. This study is aimed to investigate the density of serum miRNA-21 in patients with different phases of intracranial aneurysms (IAs) and explore its warning function for IA rupture.Methods:A total of 16 in 200 IA patients were selected and categorized into 4 groups based on the phase of IA. Microarray study was carried out using serum miRNA and differentially expressed miRNAs were identified. Another 24 samples from a cohort of 360 patients were added and real-time polymerase chain reaction (RT-PCR) was performed on expanded sample size (n = 40) for miRNA-21 validation. Potential gene targets of miRNA-21 were screened out from Gene Ontology (GO) database and literatures.Results:Microarray study identified 77 miRNAs with significantly different expression levels between experimental groups and the control group. RT-PCR assays validated significant downregulation of miRNA-21 in experimental groups, among which miRNA-21 expression level of daughter aneurysm group decreased the most. Bioinformatic analyses revealed that several target genes related with miRNA-21 may be involved in IA formation and rupture.Conclusions:This study suggested that miRNA-21 had a protective effect for intracranial vascular wall against remodeling and warning function for intracranial aneurysm rupture. Significant suppression of serum miRNA-21 in IA patients may provide diagnostic clues for aneurysm rupture and guide clinical intervention.

  • 标签: Serum miRNA-21 Intracranial aneurysm Daughter aneurysm Vascular wall remodeling
  • 简介:Inthispaper,thebendingproblemofrectangularthinplateswithfreeedgeslaidontensionlessWinklerfoundationhasbeensolvedbyemployingFourierserieswithsupplementaryterms.Byassumingproperformofseriesfordeflection,thebasicdifferentialequationwithgivenboundaryconditionscanbetransformedintoasetofinfinitealgebraicequations.Becausetheboundaryofcontactregioncannotbedeterminedinadvance.theseequationsareweaknonlinearones.Theycanbesolvedbyusingiterativeprocedures.

  • 标签: ALGEBRAIC transformed WINKLER rectangular deflection ITERATION