关于部分偏振光能量传递和偏振态的光线椭圆分析方法

部分偏振光传播时的光强和偏振态变化情况比较复杂, 尤其是当大数值孔径成像时, 光束的偏振态还会影响成像质量. 本文提出一种用于分析部分偏振光能量传递和偏振态的光线椭圆方法, 采用光线椭圆叠加的办法来分析光束在各向同性的均匀介质中传输时能量和偏振态的变化情况, 同时直观性好, 计算量小. 论文最后, 对大数值孔径、 高像质的齐明透镜系统讨论了入射无偏振光的能量、 偏振态变化, 以及偏振效应问题. 结果表明, 大数值孔径使成像光束中TM偏振光强度相对增加, 影响成像对比度; 提高像方介质的折射率, 会改善此种偏振效应问题.     

Nanoparticle coagulation in a planar jet via moment method

Large eddy simulations of nanoparticle coagulation in an incompressible pla- nar jet were performed.The particle is described using a moment method to approximate the particle general dynamics equations.The time-averaged results based on 3000 time steps for every case were obtained to explore the influence of the Schmidt number and the Damkohler number on the nanoparticle dynamics.The results show that the changes of Schmidt number have the influence on the number concentration of nanoparticles only when the particle diameter is less than 1 nm for the fixed gas parameters.The number concentration of particles for small particles decreases more rapidly along the flow di- rection,and the nanoparticles with larger Schmidt number have a narrower distribution along the transverse direction.The smaller nanoparticles coagulate and disperse easily, grow rapidly hence show a stronger polydispersity.The smaller coagulation time scale can enhance the particle collision and coagulation.Frequented collision and coagulation bring a great increase in particle size.The larger the Damkohler number is,the higher the particle polydispersity is.     

Research on the effect of cylinder particles on the turbulent properties in particulate flows

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Nanoparticle nucleation and coagulation in a mixing layer

Numerical simulation of nanoparticle nucleation and coagulation in a mixing layer with sulfuric acid vapor binary system is performed using the large eddy simulation and the direct quadrature method of moment. The distributions of number concentration, volume concentration, and average diameter of nanoparticles are obtained. The results show that the coherent structures have an important effect on the distributions of number concentration, volume concentration and average diameter of nanoparticles via continuously transporting and diffusing the nanoparticles to the area of low particle concentration. In the streamwise direction, the number concentration of nanoparticles decreases, while the volume concentration and the average diameter increase. The distributions of number concentration, volume concentration and average diameter of nanoparticles are spatially inhomogeneous. The characteristic time of nucleation is shorter than that of coagulation. The nucleation takes place more easily in the area of low temperature because where the number concentration of nanoparticles is high, while the intensity of coagulation is mainly affected by the number concentration. Both nucleation and coagulation result in the variation of average diameter of nanoparticles.     

求解脉动速度关联函数的新方法及其在平面湍尾流中的应用

将周培源给出的平面湍尾流的一级近似解作为已知量,代入湍流脉动速度方程中,在微尺度范围内,采用谱方法对该方程进行数值求解,得到了和实验结果符合的二阶、三阶、四阶脉动速度关联函数的计算结果。     

土壤内水分流动及温度分布计算——耦合型模型

本文目的在于发展一个计算土壤内水分输送及能量交換的物理模型——耦合型模型,驱动该模型的大气条件是由实测而得的,引用对蒸发的土壤表面阻抗关联了在大气中水汽通量与从地表的蒸发,由于这种阻抗引入,计算模拟的结果与实测值达到了较好的吻合。     

双取代咔唑化合物的合成及光谱性质研究

以咔唑为分子主体,选择了3种不同的共轭小分子修饰到咔唑分子上,合成了3种A-π-D-π-A型ICT化合物,研究了其光谱性能、考察了不同极性溶剂对光谱的影响,及可能的ICT过程.结果表明化合物a具有优良的电荷转移效果,有望应用于微环境极性探针及有机光电材料领域.     

液体物性对雾化射流液雾粒径的影响

对不同液体在空气中湍动雾化射流的气液两相流场进行了数值模拟.建立了一次雾化的一维模型,分析了粘度、表面张力和气液质量流量比对液雾粒径的影响趋势,采用基于粒子追踪法的二次雾化三维模型,分析了物性和各种工况对液雾粒径沿轴向分布的影响程度.计算结果和已公开发表的实验数据进行比对,得到了较好的吻合,在此基础上,分析了影响气泡雾化喷嘴雾化质量的主要因素.     

PVK∶DBVP掺杂体系的能量转移及发光性质的研究

研究了不同比例的PVK与齐聚PPV衍生物DBVP掺杂体系的能量转移和发光特性.通过对PVK,DBVP及PVK:DBVP掺杂体系的UV-vis,PL和PLE光谱的研究,分析了PVK与DBVP之间的能量转移过程.利用PVK在体系中类似于溶剂的分散作用,制备了结构为ITO/PEDOT/PVK:DBVP/LiF/Al的电致发光器件,研究了掺杂体系的电致发光性能.结果表明,在掺杂体系的光致发光和电致发光中,PVK的发射被有效地抑制,PVK与DBVP之间发生了非常有效的能量转移,通过调节PVK与DBVP的比例,可以获得蓝色和绿色发光,同时可以改善器件的发光性能,当PVK与DBVP的重量比为1∶2时,器件的绿色发光效率达到1·06cd/A,此时发光亮度为52cd/m2.