TiO2负载管状高岭土光催化剂的制备及其表征

以高岭土/甲醇插层复合物为前驱体,与十六烷基三甲基氯化铵反应制备了管状高岭土,并以此为载体,采用溶胶-凝胶法,制备了TiO2/管状高岭土光催化剂。利用X射线粉末衍射仪、傅里叶变换红外光谱仪和场发射扫描电镜分别对高岭土及其插层复合物的微观形貌与结构进行了表征。紫外光谱分析表明,与纯TiO2相比复合催化剂对光吸收利用率明显提高,并在可见光区有明显吸收。催化降解甲基橙实验表明,500W汞灯辐照30min后,复合光催化剂对甲基橙的降解效率较纯TiO2提高了30%。     

A personalized e-course composition based on a genetic algorithm with forcing legality in an adaptive learning system

This paper proposes a personalized e-course composition based on a genetic algorithm with forcing legality (called GA^?) in adaptive learning systems, which efficiently and accurately finds appropriate e-learning materials in the database for individual learners. The forcing legality operation not only reduces the search space size and increases search efficiency but also is more explicit in finding the best e-course composition in a legal solution space. In serial experiments, the forcing legality operation is applied in Chu et al.'s the particle swarm optimization (called PSO^?) and Dheeban et al.'s the improved particle swarm optimization (called RPSO^?) to show the forcing legality can speed up the computational time and reduce the computational complexity of algorithm. Furthermore, GA^? regardless of the number of students or the number of materials in the database, to compose a personalized e-course within a limited time is much more efficient and accurate than PSO^? and RPSO^?. For the experiment increasing the number of students to 1200, the average improvement ratios of errors (learning concept error, materials difficulty error, learning time error), fitness value, stability, and execution time are above 96%, 79%, 90%, and 10%, respectively. For the experiment increasing the number of materials to 500 and the execution time set to the shortest execution time of RPSO^?, the average improvement ratios of errors (learning concept error, materials difficulty error, learning time error), fitness value, and stability are above 97%, 51%, and 80%, respectively. Therefore, GA^? is able to enhance the quality of personalized e-course compositions in adaptive learning environments.     

基于FPGA的二次加权NB网络流量分类方法

针对传统网络流量分类方法不能很好地满足高速网络流量分类的实时性和准确性要求,提出了一种基于FPGA的二次加权朴素贝叶斯网络流量分类方法。该方法通过对样本属性和样本类别进行加权,并在FPGA上进行建模,从而实现网络流量的实时、准确分类。仿真实验结果表明,该方法与传统网络流量分类方法相比,提高分类精度的同时具有更好的实时性,在100MHz时钟下其分类速度约为纯软件实现分类速度的260倍。     

有关变频器驱动电动机中浪涌对策的基础研究

变频驱动的电动机,为满足节能及小型化、高性能化等市场需求,必然要面对严酷的使用条件,其中,变频器产生的浪涌(surge)对电动机绝缘系统会产生不利影响。"明电"公司在掌握变频器浪涌对电机影响的同时,使用了耐局部放电性能优越的漆包线。针对该绝缘系统的适用性进行了不断的探索研究。     

山东高速公路传送网升级改造

本文根据山东高速通信系统的现状,介绍通过使用MSTP技术对网络进行升级改造的具体实施方案。     

瑞香狼毒提取物对水稻螟虫的杀灭活性研究

本文研究了瑞香狼毒根部粗粉乙醇提取物对水稻害虫大螟和二化螟的毒杀活性,当浓度为2.0g/L、作用时间为72h,乙醇提取物对大螟致死率为92.4%,二化螟的死亡率为20.9%。同时还系统研究了瑞香狼毒根部粗粉其它极性溶剂提取物对大螟和二化螟的胃毒活性、杀卵活性和内吸活性,结果表明瑞香狼毒对水稻大螟和二化螟具有一定的杀灭作用。     

家用洗碗机能效要求比较分析

该文主要分析和介绍了世界主要发达国家／地区家用洗碗机强制性和自愿性能效要求，包括限值要求、计算和检测方法等，并对主要国家/地区的能效限值要求进行了比较分析，旨在帮助出口生产企业了解发达国家/地区在能效限值方面的要求，提高应对国外技术贸易壁垒的能力。     

A sorption rate hypothesis for the increase in H2 permeability of palladium-silver (Pd-Ag) membranes caused by air oxidation

Hydrogen permeation measurements were performed at 300 °C for 25-μm cold-rolled Pd-Ag 25 wt% membranes before and after air oxidation at the same temperature as permeation. The air oxidation resulted in enhanced H₂ permeation through the membrane, as well as a roughening of the surface with the formation of surface grains and defects. The protruding grains can be leveled off by exposure to H₂ but the surface defects cannot. These microstructure changes are only on the membrane surfaces and do not create transmembrane defects that would allow permeation for gas species other than H₂. The H₂ permeability of the oxidized membrane increased by 25-90% compared to that of the as-received film at the same permeation condition, and the membranes retained perfect H₂ selectivity over N₂. The percent improvement of H₂ permeability decreases with increasing H₂ feed pressure. A new sorption kinetics hypothesis is proposed to elucidate the increase in H₂ permeability of Pd-Ag membranes caused by oxidation. H₂ solubility and sorption rate results were presented to test the new hypothesis. It is found that air oxidation does not change the H₂ solubility in Pd-Ag membranes, but enhances the H₂ sorption kinetics significantly. The extent of kinetics enhancement also decreases with increasing H₂ pressures. The much faster sorption equilibrium implies higher effective H₂ diffusivity at the Pd-Ag membrane surface for the oxidized sample and a higher transfer rate of atomic hydrogen from surface/sub-surface to the membrane bulk that contributes to the increase of H₂ permeability observed in experiments.     

多光束发射对无线激光通信误码率的影响

在光通信系统中,湍流会导致光束漂移、强度起伏、光束扩展、相位畸变等。这些湍流效应将严重影响无线激光通信系统的稳定性和可靠性。从湍流的相关理论出发,分析了多光束发射在克服湍流影响方面的效果。该分析结果为光通信系统的设计及部署提供了重要参考。