简介:Inthepresentwork,core-shellNi@SiO2catalystswereinvestigatedinordertoevaluatetherelevanceofcatalyticactivityandsurfacestatesofNicoreaswellasNinanoparticlessizetocatalyticpartialoxidationofmethane(POM).ThecatalystswerecharacterizedbyN2adsorption,H2-TPR,XRD,TEMandXPStechniques.Thecatalyticperformanceofthecore-shellcatalystswasfoundtobedependentonthesurfacestatesofcatalyst,whichinfluencedtheformationofproducts.Itwasconsideredthatcarbondioxideformedontheoxidizednickelsites(NiO)andcarbonmonoxideproducedonthereducedsites(Ni).ThesurfacestatesofactivemetalinthedynamicwereinfluencedbothbythesizeofNicoreandtheporosityofsilicashell.However,thecatalyticactivitywouldbedebasedwhenthesizeofNicorewasunderacertainextent,whichcanbeascribedtothefactthecarbondepositionincreasedwiththeincreasingcontentofNiO.TheeffectsofsurfacestatesofNi@SiO2catalystonthecatalyticperformancewerediscussedandthereactionpathwayoverNicoreencapsulatedinsidesilicashellwasproposed.
简介:polypropylene/ethylene-propylene随机copolymer/ethylene-propylene的一系列第三的混合分割了其微观结构类似于影响聚丙烯共聚物(欧洲电脑生产厂商)的那些的共聚物(HPP/EPR/EbP)被准备以便系统地在微观结构和欧洲电脑生产厂商的结晶化行为上调查作文的效果。主要阶段形态学的观察表明有核心壳结构的驱散的阶段能在某些作文被重建,过多的EPR在第三的混合导致bicontinuous阶段结构。在包括等温、非等温的结晶化经历一样的静止结晶化以后,这些混合样品展出融化行为的特殊作文依赖者,即,融化的点随EPR内容的增加显著地增加直到它在一个批评内容(大约30wt%)拒绝。结晶化行为主要被归功于到不同成核能力。尽管在EPR和HPP部件之间的相容性随EPR的增加变得更坏,由于增加的界面的区域和EbP的减少的集中满足,这被建议,在混合的更高的EPR内容除了明显的bicontinuous的外观便于到异构的成核阶段结构。
简介:'Giant'CdSe/CdScore/shellnanocrystals(NCs)weresynthesizedwiththickCdSshell(15monolayers),andthex-raydiffraction(XRD)measurementindicatesthereisazincblendephaseinthethickCdSshell,whereasittransformedintowurtzitephaseunder5minradiationwitha400nm,594μJ∕cm2femtosecond(fs)laserbeam.TheevolutionoftheNCs’spontaneousemissionunderthefslaserradiationwasrecordedwithaHamamatsustreakcamera.Theas-synthesizedNCsexhibitanamplifiedspontaneousemission(ASE)at530nm,whichcomesfromabulk-likeCdSshellduetotheinterfacialpotentialbarrier,whichcouldslowdowntherelaxationofholesfromtheshelltothecore.Afterbeingannealedbyanfslaser,theASEoftheg-NCsistransferredfromabulk-likeCdSshelltoaquantum-confinedCdSecorebecausethephasetransformationdeterminedwiththeXRDmeasurementcouldremovetheinterfacialbarrier.BesidestheASEat643nm,twoshorter-wavelengthASEpeaksat589and541nm,correspondingtoopticaltransitionsofthesecond(1P)andthird(1D)electronquantizationshellsoftheCdSecore,alsoappear,thusindicatingthatAugerrecombinationiseffectivelysuppressed.
简介:Thermodynamicpropertiesandphasediagramsofamixedspin-(1,2)Isingferrimagneticsystemwithsingleionanisotropyonhexagonalnanowirearestudiedbyusingeffective-fieldtheorywithcorrelations.Thesusceptibility,internalenergyandspecificheatofthesystemarenumericallyexaminedandsomeinterestingphenomenainthesequantitiesarefound.TheeffectoftheHamiltonianparametersonphasediagramsareexaminedindetail.Besidessecond-orderphasetransition,linesoffirst-ordertransitionandtricriticalpointsarefound.Inparticular,wefoundthatforsomenegativevaluesofsingle-ionanisotropies,thereexistfirst-orderphasetransitions.
简介:Theshallowcylindricalstructureissuitabletodevelopbroadbandvibrationenergyharvestersduetothepropertyoftheinherentmechanicalbistability.Inthisletter,theoptimumdesignofthebistablecylindricalshellforbroadbandenergyharvestingapplicationisinvestigatedfromthestructuralpointofview.Theoutputpowerisevaluatedbytheconceptoftheharvestablepower,whichbalancesthefrequencyofsnapthroughandthereferredoutputenergyassociatedwitheachsnapthrough.Thenondimensionalharvestablepowerisanalyticallyexpressedasthefunctionofthenon-dimensionalcurvatureparameterandoneconstructedparameter.Theuniversaldependenceoftheoptimalcurvatureparameterandtheassociatedoptimalharvestablepowerontheconstructedparameterisderived,whichcanbewellapproximatedbythelinearrelationindoublelogarithmiccoordinate.
简介:由重力的分离的核心形成据说释放了足够的内部热融化地球。energetics的分析,比较重力的势能,U<潜水艇class=“a-plus-plus”>到地球当前的分层的配置的一个虚构、同类的参考状态的g),需要更新改正错误和省略,并且提供最近的调查结果:(1)一个错误的正号被用于Ug当在无穷维持0的参考价值时,它为U导致一个不正确的符号在决定一个过程是否吸热或发热关键的g,。(2)U的价值<潜水艇class=“a-plus-plus”>为地球起始的状态的g是不明确的。(3)最近的陨星证据显示在地球是完整大小的以前,那核心形成开始了,它严重地限制U<潜水艇class=“a-plus-plus”>g。(4)不同类的生长另外减少了U<潜水艇class=“a-plus-plus”>g。(5)在核心和披风之间的微分旋转的潜在地大的效果没被说明为。(6)与创造顺序联系的熵变化被忽视。因此,我们修订U的价值<潜水艇class=“a-plus-plus”>g,评估无常,并且显示出那U<潜水艇class=“a-plus-plus”>g实质地被变换成configurational能量(TS)。这些考虑限制初发的热的大来源到影响和放射性。尽管这些过程可以在核心形成起一个作用,他们的精力独立于重力的分离,它生产顺序和旋转能量,不是内部热。相反,因为它分离,重力的分离支持主要的行星的冷却lithophilic放射性的元素当弄短时,增加向上的、表面热流动放射产生的热向外在上扩散的距离。
简介:Coremodecutoffisausefulconceptnotonlyforataperedsingle-corefiber(SCF)butalsoforataperedmulticorefiber(MCF)torealizecladdingmodetransmission.Inthispaper,cut-offconditionsofeithercoremodefortaperedSCFsorsupermodesforMCFsaretheoreticallyinvestigated.RigorousanalyticalformulasarederivedforthemodesofSCFbyathree-layerwaveguidemodel,andanapproximationformulaofthecut-offconditionisgivenfortheLP01mode.ThesupermodesofMCFsareanalyzedbythecouplingmodetheory,andthecut-offconditioniscalculatedbyanumericalmethod.Simulationresultsshowthatthein-phasesupermodeofMCFshasasimilarcut-offconditionwiththatofSCF.Basedonthisproperty,aconvenientapproximateformulaisgiventoestimatethecut-offconditionofthein-phasesupermodefortaperedMCFs.
简介:随着云计算的到来,相应的大数据和物联网也随之兴起。然而网络信息安全的形势非常严峻。现在网络服务器都是集群式分布,很多服务器集中起来一起进行同一种服务,实现负载均衡,在客户端看来就像是只有一个服务器。集群可以利用多个计算机进行并行计算从而获得很高的计算速度,但是如果服务器被攻击,将会导致整个服务器集群受到影响,甚至有可能导致宕机,导致用户无法使用提供的服务,造成严重的损失。14年的qq邮箱大规模的瘫痪就是非常的例子。往往造成这种问题的是我们众所周知的DDoS。当受到DDoS攻击时,服务器流量会骤增为平时的几十倍,通过流量监控及时报警运维工程师处理,以免造成服务器大规模宕机。我们通过实时监测网卡流量变化,通过邮件引擎实现第一时间报警,及时处理,减少攻击带来的危害。
简介:A3D非静水力学的模型葡萄(全球/地区性的吸收和预言系统)的动态核心在Yin-Yang格子上被开发处理极的问题并且提高计算效率。强迫的三维的Coriolis被介绍给新核心,并且强迫的Coriolis的完整的表示使分享在殷和杨子域之间的代码直接。类似于在葡萄建模的原版,一个半含蓄的semi-Lagrangian计划与跨边界的运输的另外的安排为时间的集成和移流被采用。在时间的非集中的秒顺序和空间discretization下面,干燥nonhydrostatic框架作为一个椭圆的问题的答案被总结。产生Helmholtz方程被解决与概括与经典Schwarz方法在合作结合剩余解答者。尽管方程的系数与在原来的模型的那些相当不同,新核心的计算过程只是一样。双性人立方的Lagrangian插值服务向Dirichlet类型边界条件提供在子域之间的数据转移。干燥核心与几个基准测试用例被评估,并且所有测试显示合理数字稳定性和计算性能。平衡流动的坚持和导致山脉的Rossby波浪和Rossby-Haurwitz波浪的开发在半含蓄的semi-Lagrangian证实3DCoriolis条款的适当安装Yin-Yang格子上的动态核心。
简介:Inthispaper,wepresentamode-selectivecouplerbasedonadual-coreall-solidphotonicbandgapfiber(AS-PBGF).Becausetheyareall-solid,AS-PBGF-basedmodeconvertersareeasiertosplicetootherfibersthanthosebasedonair-holephotoniccrystalfibers.ModeconversionsbetweentheLP01andLP11modes,LP01andLP21modes,andLP01andLP02modesareobtainedatthewavelengthλ=1550nm.The3dBwavelengthbandwidthofthesemodeconvertersare47.8,20.3,and20.3nm,respectively.
简介:TheequationofmotionofsandwichbeamwithpyramidallatticecoreinthesupersonicflowconsideringgeometricnonlinearityisformulatedusingHamilton’sprinciple.Thepistontheoryisusedtoevaluateaerodynamicpressure.Thestructuralaeroelasticpropertiesareanalyzedusingfrequency-andtime-domainmethods,andsomeinterestingphenomenaareobserved.Itisnotedthattheflutterofsandwichbeamoccursunderthecouplingeffectoflowordermodes.Thecriticalflutteraerodynamicpressureofthesandwichbeamishigherthanthatoftheisotropicbeamwiththesameweight,lengthandwidth.Theinfluenceofinclinationangleofcoretrussonfluttercharacteristicisanalyzed.
简介:在这份报纸,CD衍生物的三种不同类型作为原子转移激进分子聚合(ATRP)被综合开始者或可逆增加破碎链转移聚合(木排)链转移。为每衍生物的替换的度小心地被描绘通过<啜class=“a-plus-plus”>1H-NMR,<啜class=“a-plus-plus”>13C-NMR光谱学和飞行团spectrometry(MALDI-TOF-MS)的帮助矩阵的激光解吸附作用/电离时间。影响替换的度的因素被讨论。而且,在ATRP和木排之间的比较在N-isopropylacrylamide(NIPAM)的聚合被显示出。