Increasing rewriting speed of optical rewritable e-paper by selecting proper liquid crystals

Effect of interaction between liquid crystal (LC) and photoalignment material on speed of optical rewriting process is investigated. The theoretical analysis shows that smaller frank elastic constant K₂₂ of liquid crystal corresponds to larger twist angle, which gives rise to larger rewriting speed. Six different LC cells with the same boundary conditions (one substrate is covered with rubbed polyimide (PI) and other with photo sensitive rewritable sulfuric dye 1(SD1)) are tested experimentally under the same illumination intensity (450 nm, 80 mW/cm²). The results demonstrate that with suitable liquid crystal, LC optical rewriting speed for e-paper application can be obviously improved. For two well known LC materials E7 (K₂₂ is larger) and 5CB (K₂₂ is smaller), they require 11 s and 6 s corresponding to change alignment direction for generating image information.     

Separation control in a conical diffuser with an annular inlet: center body wake separation

In many practical applications of conical diffusers, the flow is fed by an annular flow passage formed by a center body. Flow separation, which occurs if the center body ends abruptly, is undesirable because it degrades the diffuser performance. The present experiment utilizes magnetic resonance velocimetry to acquire three-component mean velocity measurements for a set of conical diffusers with an annular inlet. The results show strong coupling between the diffuser wall boundary layer development and the wake of the center body. Coanda blowing is used to mitigate the center body wake separation. The diffuser wall boundary layer is thick in the absence of the central separation bubble and separates when Coanda blowing is too strong.     

Electronic transmission of three-terminal pyrene molecular bridge

This paper investigates theoretically the electronic transmission spectra of the three terminal pyrene molecular bridge and the quantum current distribution on each bond by the tight-binding model based on nonequilibrium Green's function and the quantum current density approach, in which one π molecular orbital is taken into account per carbon atom when the energy levels and HOMO-LUMO gap are obtained. The transmission spectra show that the electronic transmission of the three terminal pyrene molecular bridge depends obviously on the incident electronic energy and the pyrene eigenenergy. The symmetrical and oscillation properties of the transmission spectra are illustrated. A novel plus-minus energy switching function is found. The quantum current distribution shows that the loop currents inside the pyrene are induced, and some bond currents are much larger than the input and the output currents. The reasons why the loop currents and the larger bond currents are induced are the phase difference of the atomic orbits and the degeneracy of the molecular orbits. The calculations illustrate that the quantum current distributions are in good agreement with Kirchhoff quantum current conservation law.     

拟变分包含及不动点问题公解的算法

介绍了一种新的迭代算法,在Hilbert空间的框架下,用以寻求具多值极大单调映象和逆-强单调映象的变分包含的解集与非扩张映象的不动点集的公共元．在适当的条件下,逼近于这一公共元的某些强收敛定理被证明．所得结果是新的,它不仅改进和推广了Korpelevich 的结果,而且也推广和改进了Iiduka和Takahashi,Takahashi和Toyoda,Nadezhkina和Takahashi及Zeng和Yao等人的最新结果．     

Syntheses of L‐Glutamic Acid Analogues for Neuroexcitatory Activity Studies

Starting from D–serine, (2S,3S)‐, (2S,3R)‐substituted‐L‐glutamic acids were prepared via Claisen rearrangement methodology. A variety of the substituents can be introduced at the C‐3 of the L‐glutamic acid backbone.     

2,9-二甲基-1,10-菲咯啉的α-氨甲基吡啶衍生物的合成表征及其MnⅡ,CoⅡ,NiⅡ,CuⅡ,ZnⅡ配合物稳定性研究

以 2 ,9 二甲基 1,10 菲咯啉为初始原料 ,合成了 2 ,9 二甲基 1,10 菲咯啉的α 氨甲基吡啶衍生物 N ,N’ 二 (2’ 吡啶基 )甲基 1,10 菲咯啉 2 ,9 二甲胺 (L)。该配体经过元素分析、红外光谱、核磁共振氢谱表征。在2 5± 0 .1℃、I=0 .1mol·dm- 3NaNO3的条件下 ,用 pH电位滴定法测定了该配体在水溶液中的质子化常数及其分别与Mn ,Co ,Ni ,Cu 和Zn 的配合物的稳定常数 ,提出了配合物的可能结构。进一步讨论了相应稳定常数较大的内在原因     

Microscopic simulations of molecular cluster decay: Does the carrier gas affect evaporation?

We develop a kinetic theory of cluster decay by considering the stochastic motion of molecules within an effective potential of mean force (PMF) due to the cluster. We perform molecular dynamics simulations on a 50-atom argon cluster to determine the mean radial force on a component atom and hence the confining potential of mean force. Comparisons between isolated clusters and clusters thermostatted through the presence of a 100-atom helium carrier gas show that the heat bath has only a slight effect upon the PMF. This confirms the validity of calculations of cluster properties using isolated cluster simulations. The PMF is used to calculate the atomic evaporation rate from these clusters, and results are compared with the predictions of the capillarity approximation together with detailed balance, both components of the classical theory of aerosol nucleation.     

不同溶解氧水平上覆水中DOM荧光特性及总氮含量评估

采用荧光光谱技术研究不同溶解氧(DO)水平下二十埠河底泥上覆水中溶解性有机物(DOM)转化特性及类蛋白荧光强度与总氮浓度的关系。三维荧光光谱显示：上覆水中DOM主要由三种类蛋白物质(高激发波长类酪氨酸、低激发波长类酪氨酸、低激发波长类色氨酸)和两种类富里酸物质(紫外区类富里酸、可见区类富里酸物质)组成,类蛋白物质是上覆水中DOM的主要成分。经过曝气后类蛋白荧光强度均存在明显降低,其中低激发波长酪氨酸和低激发波长色氨酸相对于高激发波长酪氨酸更易被微生物降解。而类富里酸荧光强度则均呈现增强趋势,表明类富里酸物质属于难降解有机物。上覆水中DOM荧光指数介于1.65~1.8之间,表明上覆水体DOM既有陆源又有生物源但以生物源为主。荧光指数随DO增加而增大,说明随着DO增加微生物量及微生物活性逐渐增加,微生物代谢功能增强,使得上覆水中DOM的生物源成份加大。在较高的溶解氧水平下,即DO分别为2.5,3.5和5.5 mg·L-1时,高激发波长类酪氨酸峰A的荧光强度与上覆水中总氮浓度有良好的相关性,相关系数(r2)分别为0.956,0.946,0.953,说明可以通过三维荧光技术监测高激发波长类酪氨酸峰A的荧光强度而快速分析上覆水中总氮浓度,为河道水体诊断、治理及修复提供快速有效的技术参考和理论支持。     

FOX-12制备过程的反应机理及动力学

采用量子化学计算方法, 在B3LYP/6-311G(d,p)水平上研究了N-脒基脲二硝基酰胺盐(FOX-12)制备过程的反应机理. 优化得到了反应势能面上各稳定点的几何构型, 通过内禀反应坐标(IRC)确认了反应物、 中间体、 过渡态及产物之间的相关性. 为了得到更可靠的反应能量和势能面信息, 进一步在MP2/6-311++G(3df,3pd)水平上对得到的构型进行能量校正, 结果表明, 先取代磺酸基通道(A1)和先取代氢通道(B)都能生成二硝基酰胺酸(HDN), 其中通道A为主反应通道; HDN可以通过HDN→FOX-12与HDN→ADN→FOX-12 两种途径转化为目标产物FOX-12, 而第2种途径为较优途径. 应用经典过渡态理论(TST)与变分过渡态理论(CVT)以及小曲率隧道效应模型校正的变分过渡态理论(CVT/SCT)计算了在200~400 K范围内各反应通道相关基元反应的速率常数, 提供了在上述温度区间内的三参数Arrhenius关系式.     

可补偿偏置漂移的扭转光纤电流传感器

针对扭转光纤电流传感器由于环境因素（如温度,压力,振动）变化使光纤中传输光偏振态改变,从而导致传感器输出与漂移问题,提出了一种新的信号处理方法进行克服,这一方法适用于交变电流的检测,实验中通过旋转输入线偏振光偏振方向的方法检验了所提垢有效性,证明这种补偿方法对传感器置相位的任意偏移均适用。