反应物振动量子数对O(~1D)+HBr→OH+Br立体动力学影响的研究

采用准经典轨线(QCT)方法计算了O(1D)+HBr→OH+Br反应体系的立体动力学反应.基于由Peterson(J.Chem.Phys.113(2000)4598)等人开发的基态势能面上,计算了反应的矢量相关性质,极角p(θ)r及方位角pφ()r以及空间角pθr,φ()r.此外我们还计算了极化微分反应截面(PDDCSs)的分布各矢量性质随各振动量子数变量的变化.结果表明反应受反应物振动量子数影响较大.     

Magnetically Aligned Supramolecular Hydrogels

The magnetic‐field‐induced alignment of the fibrillar structures present in an aqueous solution of a dipeptide gelator, and the subsequent retention of this alignment upon transformation to a hydrogel upon the addition of CaCl₂ or upon a reduction in solution pH is reported. Utilising the switchable nature of the magnetic field coupled with the slow diffusion of CaCl₂, it is possible to precisely control the extent of anisotropy across a hydrogel, something that is generally very difficult to do using alternative methods. The approach is readily extended to other compounds that form viscous solutions at high pH. It is expected that this work will greatly expand the utility of such low‐molecular‐weight gelators (LMWG) in areas where alignment is key.     

Bent-core liquid crystal-functionalised flexible polymer substrates for liquid crystal alignment

ABSTRACT

A transparent flexible polymer film is chemically functionalised with a bent-core liquid crystal (BCLC) compound for effective alignment of the bulk BCLC sample at the substrate–LC interface. The surface attachment was achieved via a simple procedure which involved pre-treatment of the polymer film (commercial name: over head projector film) using piranha solution followed by chemically attaching the BCLC compound through silane condensation reaction. Surface characterisation of the unmodified and BC-modified flexible films was carried out through X-ray photoelectron spectroscopy (XPS), attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, contact angle (CA) and atomic force microscopy (AFM) techniques. The BC-modified flexible substrates are analysed for their efficiency to orient the bulk LC sample. Remarkably, the chemically modified polymer substrates are highly efficient in vertically aligning both the BC and rod-like LC samples at the substrate–LC interface, in comparison to their unmodified counterparts. The described method is simple, reproducible, surface modified substrates are highly stable and more importantly reusable. The demonstrated method for the alignment of BCLCs advances a step forward towards the realisation of applications proposed for these fascinating compounds.     

Aligning retention time shifts in HPLC three‐dimensional spectra by icoshift approach combined with data arrangement methods and the release of a graphical user interface

High‐performance liquid chromatography coupled with photodiode array detection has been extensively applied in many fields and the peaks among the analyzed samples can be shifted due to the variations of instrumental and experimental conditions. In multivariate analysis, retention time alignment is an important pretreatment step. Hence, the shifted peaks in high‐performance liquid chromatography coupled with photodiode array detection three‐dimensional spectra should be aligned for further analysis. Being motivated by this purpose, the interval correlated shifting method combined with the proposed data arrangement methods are recommended and employed on high‐performance liquid chromatography coupled with photodiode array detection data as a demonstration. We validate the alignment performance of the proposed method through comparison the consistency of the retention time before and after alignment. The obtained results demonstrated that the proposed method is capable of successful aligning the employed data. Additionally, the interval correlated shifting method combined with the data arrangement modes is implemented in an easy‐to‐use graphical user interface environment and so can be operated easily by users not familiar with programming languages.     

基于像差特征分析的变焦光学系统装调

提出了一种基于像差特征分析的变焦系统共轴性装调方法。针对某型20倍变焦光学系统的装调,在分析变焦光学系统装调要求的基础上,通过采用光学定心加工技术,提高变焦系统各镜组内光学元件的同轴度;采用Zygo干涉仪,检测变焦系统在长短焦位置的像差特性分布;借助CodeV软件仿真计算各光学元件在系统中的公差灵敏度分布,并确定产生像差影响的敏感光学元件;在中心偏测量仪上,完成最终光学系统像质的调整。此外,还设计了一种变焦光学系统各动组间同轴度调试装置,对变焦相机主镜筒机械内孔轴线与直线导轨的平行性进行了精确测量,保证了动组组元光轴的同轴精度。装调结果表明:变焦系统成像质量有明显改善,像面一致性得到保证,长短焦轴上传递函数值分别优于技术要求值0.45和0.55,长短焦轴外0.7视场传递函数值优于0.25和0.35,实现了高精度装调,验证了该方法的可靠性。     

基于EKF的水下LD通信精对准控制算法

高速激光通信中接收机与光斑中心很难处于精对准状态,导致水下光通信链路难以稳定建立.首先采用蒙特卡洛仿真统计法分析激光光子在海水中传输的接收光强分布规律,再通过实验对接收端的光斑图像进行采样分析,利用曲线拟合得到接收器位置与接收光强的关系.仿真与实验结果表明:光束经过25 m的水下传输,接收光强分布仍近似为高斯分布.采用非线性估计算法(扩展卡尔曼滤波)与基本状态控制反馈理论,根据接收光强度估计接收器当前位置与最大光强处的距离,通过反馈算法实现接收端与光斑中心的主动跟踪对准.算法仿真结果显示,接收端对准误差在2 mm以下,稳定后接收效率超过98%.     

压印光刻中的两步对正技术

压印光刻中套刻需要粗、精两级对正.实验采用一对斜纹结构光栅作为对正标记.利用物镜组观察光栅标记图像的边界特征进行粗对正,其准确度在精对正信号的捕捉范围内;利用光电接收器件阵列组合接收光栅莫尔信号,在莫尔信号的线区进行精对正.由于线性区的斜率大, 精对正过程中得到相应x,y方向的对正误差信号灵敏度高,利用高灵敏度对正误差信号作为控制系统的驱动信号,对承片台进行驱动定位,实现精对正.最终使X,Y方向上的重复对正准确度分别达到了± 21 nm(± 3σ)和±24 nm(± 3σ).     

Fabrication of Pre-tilted Vertical Alignment Layers for High-Speed Liquid Crystal Display Using Bi-functional Photoreactive Monomers

Abstract

To enable recent 3D and moving picture applications, liquid crystal displays (LCD) must exhibit fast response and wide viewing angle characteristics. Pre-tilted vertical alignment layers for high-speed LCD were fabricated using bi-functional photoreactive monomers. The monomers can be confined to the polyimide layer and photo-polymerized by UV exposure under voltage. Response characteristics of photo-controlled alignment films according to the structure were investigated. Vertical alignment properties were evaluated using a polarizing optical microscope, and electro-optical characteristics were compared through the voltage-transmittance curve and response time measurement. Faster response speed could be obtained by using photoreactive monomers having a long alkyl chain.     

利用扫描开尔文探针显微镜观察薄膜光电器件能级排布

薄膜光电器件的能级结构直接决定了载流子的产生、分离、传输、复合和收集等微观动力学过程,从而决定了器件性能。因此准确获取器件能级结构,是深入理解器件工作机制、推动器件技术革新的重要科学依据。此专论系统地介绍了本课题组利用扫描开尔文探针显微镜(SKPM)表征薄膜光电器件如有机太阳能电池、有机-无机钙钛矿光探测器等器件中界面能级结构的工作。垂直型薄膜器件中的活性材料层被顶电极与底电极封闭,通常难以直接在器件工况下测量其中的界面能级排布,我们发展了横截面SKPM技术来解决这一难题。研究表明,界面层是调控器件能级结构、决定器件极性、提高器件性能的重要手段。本文介绍的表征技术有望在各种薄膜光电器件,诸如光伏器件、光探测器、发光二极管,尤其是各种叠层构型器件的研究中展现出广阔的应用前景。     

自抗扰控制技术在捷联惯导动基座初始对准中的应用研究

提出并设计了应用自抗扰控制技术(ADRC)的捷联惯性系统动基座初始对准方案。通过数字仿真，将卡尔曼滤波与自抗扰控制的性能进行了详细的比较，证明该方法具有对准时间快，精度高，抗干扰能力强等特点。