量子点网点导光板的制备及性能研究

为了实现量子点背光源的白平衡,将红量子点和绿量子点与油墨均匀混合,采用丝网印刷的工艺将混合后的量子点浆料印刷到导光板的下表面,作为导光板的网点,在侧边蓝光LED激发下,使红、绿量子点发光并和蓝光共同复合发光。通过调整优化量子点在混合浆料中的比例和红、绿量子点的配比最终实现白平衡。利用OLYMPUS显微镜、F-4600荧光分光光度计和SRC-200M光谱彩色亮度计对量子点网点导光板表面形貌和光学性能进行了表征和分析。实验结果表明:当量子点在混合浆料中的质量分数为7%并且红量子点和绿量子点满足1∶12时,能够实现白平衡,CIE 1931色坐标为(0.330 8,0.327 1),色温为5 588 K,在100 m A的激发电流下亮度可达4.136×10~3cd/m~2,色域为NTSC的122.4%。     

Parametric resonance,stability and heteroclinic bifurcation in a nonlinear oscillator with time-delay: Application to a quarter-car model

This work examines dynamical behavior of a nonlinear oscillator with symmetric potential that models a quarter-car forced by the road profile under parametric excitation. The parametric resonance of a harmonically excited nonlinear quarter-car model with position and velocity time-delayed active control are investigated. We focus on the influence of delay and parametric excitation in the system. The influence of parametric excitation, time-delay and feedback gain parameters on the stability of the steady state response are investigated. By means of Melnikov's method, conditions for onset of chaos resulting from heteroclinic bifurcation is derived analytically and numerically.     

纳米结构金属表面的近场电势分布

基于均匀外电场中金属纳米半球颗粒按一定对称性从平面衬底生长出的表面结构,建立纳米半球颗粒表面附近近场电势的理论模型.采用数值计算方法得到近场电势的空间分布,并以三维曲面的形式给出.结果表明:电势分布呈现明显的几何对称性.结果为解释与纳米结构薄膜表面有关的各种异常现象提供依据,为纳米结构薄膜材料的应用研究提供参考.     

量子环上粒子体系的计算

对于量子环上带电粒子体系,组成本征函数的基矢数及哈密顿矩阵元素数都极大,数值计算量庞大.本文介绍在处理此问题时按轨道总角动量分类从基矢集中选择子基矢集的方法和技巧.应用计算机进行数值计算时,此方法比以往节省90%以上的时间.     

关于一类拟线性退化抛物方程

对拟线性退化抛物方程θ_(xx)u uθ_yu-θ_tu=f(·,u)进行了研究,得到了在[O,T]×Ω上的初边值问题解的存在唯—性,这里要求T充分小．     

Numerical Simulations of femtosecond-laser-induced dynamic alignment of molecules in the high-frequency off-resonance regime

The motion equation for ? between the molecular axis and laser polarization direction in a high-frequency off-resonance femtosecond laser field is deduced while simultaneously examining the effects of a permanent dipole moment and field-induced polarizability and hyperpolarizability to molecular rotation. Femtosecond-laser-induced dynamic alignment of CO, N₂, and Br₂ molecules are investigated by numerically solving the obtained rotation equation for the angle ?. The effects of the molecular permanent dipole moment and the field-induced polarizability and hyperpolarizability on the degree of alignment are presented at different intensities. Our computational results show that the dynamic alignment of molecules is primarily determined by field-induced polarizability and the second hyperpolarizability for the laser intensity range from 5 × 10¹⁴ to 5 × 10¹⁶ W/cm². The contributions of higher order correction terms to molecular alignment can usually be neglected. The polarizability-field interaction makes the angular distributions of a molecule have a maximum along the polarization axis and a minimum perpendicular to it. The role of the second hyperpolarizability keeps the molecular counts maximum along the laser polarization direction but minimum at an angle of 45° between the molecular axis and the polarization direction. There is also a second maximum of molecular counts perpendicular to the polarization axis. For CO, N₂, and Br₂ molecules, the dependences of laser-induced dynamic alignment on laser intensity exhibit completely different characteristics.     

Effect of electric field on the spectrum and the persistent current of a quantum ring with two electrons （II） additional effect of a charged impurity

This paper studies the effect of a charged impurity together with or without an external homogeneous electric field on a quantum ring threaded by a magnetic field B and containing two electrons. The potential caused by the impurity has been plotted which is helpful to the understanding of the electronic structures inside the ring. The deep valley appearing in the potential curve is the source of localization, which affects seriously the Aharonov-Bohm oscillation （ABO） of the energy and persistent current. It also causes the fluctuation of the total orbital angular momentum L of the pair of electrons. It is found that the appearance of the impurity reduces the domain of the fractional ABO. During the increase of B, the domain of the integral ABO may appear earlier when B is even quite small. The transition from the localized states to extended states has also been studied. Furthermore, it has deduced a set of related formulae for a transformation, by which an impurity with a charge ep placed at an arbitrary point Rp is equivalent to an impurity with a revised charge ep placed at the X-axis with a revised radial distance Rp. This transformation facilitates the calculation and make the analysis of the physical result clearer.     

中性红催化动力学光度法测定痕量硒(Ⅳ)

利用硫酸介质中,痕量硒(Ⅳ)强烈催化氯酸钾氧化中性红褪色反应,建立一种快速测定痕量硒(Ⅳ)的催化动力学光度法.结果表明:最大吸收波长为530nm,检出限为2.4×10-9g/mL,摩尔吸光系数为2-71×104L·mol-1·cm-1,硒含量在0.1-0.4/μg/25mL范围内呈线性关系,线性回归方程为AA=0.0045 0.4271CSe(Ⅳ)(μg//25mL),相关系数r=0.9996,直接用于黑木耳、黄花菜和香菇中硒(Ⅳ)的测定,结果令人满意.     

‐type stability criteria in division regions for multitime‐scale networks with delays

This paper is concerned with new results on ‐type stability criteria in division regions for competitive neural networks with different time scales. Under the decomposition of state space, both the neural activity levels (the short‐term memory) and the synaptic modifications (the long‐term memory), are taken into account in constructing division regions that allow the coexistence of equilibrium points. Meanwhile, novel delay‐dependent multistability and monostability criteria are established in division regions that depend on divisions in index set of neurons and boundedness of unsupervised synaptic variables. The attained results show the effects of self‐interactions of neurons and Hebbian learning behavior on the multistable convergence of the networks. Finally, numerical simulations will illustrate multistable neuron activity and synaptic dynamics of multitime‐scale competitive networks. Copyright © 2011 John Wiley & Sons, Ltd.