Quantitative analysis of the dynamic behaviour of photochromic systems

The good understanding of a photochromic reaction mechanism requires the establishment of the list of all the transient species and the definition of their connecting processes. The purpose of kinetic studies is the determination of the main photochromic parameters, such as the quantum yields of photoisomerization, rate constants of thermal relaxation and spectra of transient species. These data allow the establishment of structure properties relationships in order to select the best substituents to improve photochromic performances within a given series. In this review, we describe the dynamic behaviour of various photochromic systems during thermal relaxation after irradiation, from the simplest mono-exponential decay to the more complicated multi-exponential dynamics. Then, we analyse the evolution of the long-lived isomers under continuous irradiation. Several pedagogical examples and tricks to perform easy kinetic analysis are given in the appendices.     

Functionality of nano titanium dioxide on textiles with future aspects: Focus on wool

The consumption of titanium dioxide in today's world is on the increase. As the most popular nano substance, TiO₂ is used in various industries notably in the textile industry. More and more recently, through a synergistic combination of photocatalytic features of nanoparticles, fabrics with novel properties are produced. Self-cleaning and stability against UV rays as well as chemical media, to name but a few, are among new prominent properties, obtained on textiles. A common subject reported in most studies has been the diverse approaches to immobilize the nanoparticles on the surface of fabrics. Wool is among common textile materials that have undergone numerous processes to be modified. This review intends to bring to light different aspects of application of nano titanium dioxide in the textile industry especially on wool, and also presents a concise overview on the rigorous pieces of research conducted in this realm.     

Hierarchical ZnO/Cu "corn-like" materials with high photodegradation and antibacterial capability under visible light

A novel hierarchical ZnO/Cu "corn-like" material was successfully synthesized via facile low temperature hydrothermal and photo-deposition methods. This novel hierarchical material was well characterized by FESEM, XRD, EDS, UV-Vis. This novel material displayed high photodegradation and antibacterial capability under the irradiation of visible light. This is owing to its unique properties, including maximized light utilization rate via red-shifting the light absorption spectrum, enhanced specific surface area for mass transfer and reaction sites, and retarded recombination of photogenerated electrons and holes. Moreover, this novel hierarchical ZnO/Cu "corn-like" material demonstrated easy recovery from treated water for reuse. All these excellent properties indicate that this novel hierarchical ZnO/Cu "corn-like" material has a bright future in water purification applications.     

数字卫星电视系统的相关测量

卫星信道的测试是广大卫星工作者的日常工作之一,正确理解所测参数的意义和测试原理,对于做好日常工作、提高工作水平是非常重要的.作者通过对各种测量参数的深入的理论分析,并结合多年的实践经验,阐述了数字卫星电视系统的相关测量原理,为卫星信道测试工作提供了理论依据.     

一种有效的违章车辆抓拍方法

在道路监控系统中，违章车辆的抓拍是至关重要的一环，抓拍效果的好坏直接影响后续处理的进行。文章提出一种较有效的违章车辆的抓拍方法。实践证明，该方法实时性好。准确度高，具有较高的实用价值。     

VSB解调器中的载波相位跟踪环

本文提出了一种专门用于数字ＶＳＢ解调的载波相位跟踪环，它实际上包括两个可视相互独立的子环，其一用于相位跟踪，另一用于幅度抖动补偿，在噪声和非噪声环境下，该环路均具有较好的性能，文中对此进行了理论分析和计算机仿真，结果表明，在ＨＤＴＶ地面传输系统约１５ｄｂ的信噪比门限下，该环路仍能可靠地工作。     

一种电视倍行处理电路的实现

本文成功地设计了包括行重复和行内插在内的倍行处理电路,来抑制和消除行间闪烁及爬行现象,提高图像质量。并通过实验观察了倍行处理的实际效果。     

Frame-level bit allocation based on incremental PID algorithm and frame complexity estimation

Since the current rate control schemes in H.264 do not have the capability of efficient frame-level bit allocation, the video quality varies significantly from frame to frame especially for sequences with sudden scene changes or high motion activities. To overcome the limitation of frame-level bit allocation, we improve H.264 rate control scheme using two tools, the incremental proportional–integral–differential (PID) algorithm and the frame complexity estimation. The incremental PID algorithm is first introduced to control the buffer and reduce the influence of the buffer abrupt fluctuation in the process of frame-level bit allocation. To reduce more video quality variations, the frame target bit allocation is also adjusted by frame complexity that is estimated by residual energy. Simulation results show that the proposed rate control scheme, without introducing expensive computational complexity, decreases the average standard deviation of video quality by 32.29%.     

基于改进人工鱼群-蛙跳算法优化LSSVM参数短期负荷预测

短期电力负荷预测在电力系统安全调度、经济运行方面起到关键作用。在用最小二乘支持向量机进行负荷预测时,参数选择将直接影响预测精度。为了提高LSSVM负荷预测精度,文中提出一种基于Levy变异自适应视野人工鱼群-蛙跳算法对LSSVM进行参数优化的方法。以某县负荷、天气等历史数据对LSSVM进行训练,建立LAVAFSA-SFLA-LSSVM、AFSA-LSSVM、LAFSA-SFLA-LSSVM共3种预测模型,对该地区某日24 h的电力负荷进行预测。算例结果表明,LAVAFSA-SFLA-LSSVM预测精度比AFSA-LSSVM和LAFSA-SFLA-LSSVM更高,预测误差更小。