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8 个结果
  • 简介:采用噻吩-2-甲醛分别与邻氨基苯硫酚和硫代氨基脲合成了2种噻吩-2-甲醛杂环席夫碱.利用红外光谱、紫外-可见光谱、荧光光谱、X-射线单晶衍射分析、热重分析和核磁共振氢谱等检测方法对2种目标新型杂环类席夫碱产物的结构和性质进行了表征与分析.采用量子化学中常用的密度泛函方法(DFT)对2种新席夫碱化合物进行几何优化,采用单激发组态相互作用(CIS)和含时密度泛函方法(TD-DFT)进一步优化,比较计算光谱与实际测试光谱之间的误差,探究了2种席夫碱化合物荧光发光机制,为这类席夫碱分子结构设计提供了理论依据.

  • 标签: 杂环席夫碱 噻吩-2-甲醛 密度泛函理论
  • 简介:WeconsiderdiffusivelimitoftheBoltzmannequationinaperiodicbox.WeestablishL~6estimateforthehydrodynamicpartPfofparticledistributionfunction,whichleadstouniformboundsglobalintime.

  • 标签: L~6 ESTIMATE BOLTZMANN EQUATION diffusive LIMIT
  • 简介:WeinvestigatethenonlinearSchrdingerequationiut+△u+|u|p-1u=0with1+4/N||Q||(1-sc)/sc|▽Q||2,theneitheru(t)blowsupinfiniteforwardtimeoru(t)existsgloballyforpositivetimeandthereexistsatimesequencetn→+∞suchthat||▽u(tn)||2→+∞.HereQisthegroundstatesolutionof—(1—sc)Q+△Q+|Q|p-1Q=0.Asimilarresultholdsfornegativetime.Thisextendtheresultofthe3DcubicSchr(o|¨)dingerequationobtainedbyHolmertothegeneralmass-supercriticalandenergy-subcriticalcase.

  • 标签: NLS方程 SCHRODINGER forward 发散 EXTEND cubic
  • 简介:在这研究,(L减水乳酸)(PLLA)一系列monodispersed被戒指洞聚合poly综合与Schiff基础铝催化剂,并且数字一般水准的效果分子的重量(M结晶化和PLLA的融化的行为上的n)被微分扫描热量测定(DSC)和宽角度的X光检查衍射(WAXD)调查。PLLA的全部的结晶化率是M与M-dependent,>18.6kg/mol的n。另外,当PLLA的Mn是18.6kg/mol时,融化的热含量(Hm)显示出最大的价值(87.1J/g),它是最高报导的价值到现在为止。为水晶形成从的变化的批评温度-到形式,在等温的结晶化增加的晶体与M处理n增加。在再热的过程,high-MnPLLA在主导的融化山峰以前表明了一座小exothermal山峰,相应于水晶转变从-到-form,但是low-MnPLLAdidnt表演水晶转变的山峰。这些不同结晶化和融化的行为与不同Mn。

  • 标签: 下线 服务 迁移
  • 简介:Basedontherangespaceproperty(RSP),theequivalentconditionsbetweennonnegativesolutionstothepartialsparseandthecorrespondingweightedl_1-normminimizationproblemarestudiedinthispaper.Differentfromotherconditionsbasedonthesparkproperty,themutualcoherence,thenullspaceproperty(NSP)andtherestrictedisometryproperty(RIP),theRSPbasedconditionsareeasiertobeverified.Moreover,theproposedconditionsguaranteenotonlythestrongequivalence,butalsotheequivalencebetweenthetwoproblems.First,accordingtothefoundationofthestrictcomplementaritytheoremoflinearprogramming,asufficientandnecessarycondition,satisfyingtheRSPofthesensingmatrixandthefullcolumnrankpropertyofthecorrespondingsub-matrix,ispresentedfortheuniquenonnegativesolutiontotheweightedl_1-normminimizationproblem.Then,basedonthiscondition,theequivalenceconditionsbetweenthetwoproblemsareproposed.Finally,thispapershowsthatthematrixwiththeRSPoforderkcanguaranteethestrongequivalenceofthetwoproblems.

  • 标签:
  • 简介:(L减水乳酸)(PLLA)Poly,/pristine蛭石nanocomposites被准备由融化掺双轴的extruder,和热、机械的性质的蛭石分散状态的详细信息和蛭石的效果系统地被学习。当装载内容不超过3wt%时,结果证明在矩阵的蛭石的分散相当好。太古的蛭石能显然在nonisothermal结晶化期间改进融化结晶化温度。两结晶化时间跨度和PLLA的spherulitic尺寸由提高PLLA的主要成核在等温的结晶化状况下面与蛭石的增加的数量减少。并且增加的蛭石能也改进张力的模量和PLLA的Izod影响力量。为PLLA上的蛭石的起核心作用的效果的内在的机制被建议是在蛭石和PLLA之间的取向附生的结晶化和特定的相互作用。

  • 标签: 下线 服务 迁移
  • 简介:Carbonsurfacewithlargeoxygenandcarbonratio(O/C)indicatedanoutstandingelectro-catalyticactivitytowardL-ascorbicacidoxidation,comparedtoplatinumgroupmetals.However,interrelationofsurfacefunctionalgroupsanditselectro-catalyticactivityisstillunclear.Inthispaper,weprepareddifferentlevelsofoxidizedcarbonsbyasimpleacidtreatmentandinvestigatedthecorrelationbetweenthesurfaceoxygenfunctionalgroupsofacid-treatedcarbonandelectro-catalyticactivityinanelectrooxidationofL-ascorbicacid.Positivelychargedcarbonwasdemonstratedbylonepairelectronofoxygenfromvalencebandspectrastudy.Itwasrevealedthatthepositivelychargedcarbon,especiallyinvolvedincarbonyl,showedenhancedtheelectro-catalyticactivitythroughbothbetteradsorptionofnegativelychargedreactantsandloweredLUMObyelectronegativityofoxygen.

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  • 简介:本文讨论随机环境两性分支过程中以条件均值增长率的上界作为规范化因子的L^1一收敛问题,给出了L^1一收敛的对数判别准则的充要条件.

  • 标签: 随机环境 两性分枝过程 L^1一收敛