Nanocrystalline CeO2 in SBA-15: Performance of Pt/CeO2/SBA-15 Catalyst for Water-gas-shift Reaction

CeO₂ particles confined within the pores of an SBA-15 mesoporous silica host were prepared by incipient wetness impregnation (IMP) and deposition precipitation (DP) methods. The materials were characterized by XRD, N₂-adsorption and temperature programmed reduction (TPR) to evaluate the structure, texture, and redox properties. The preparation procedure had significant impact on the assembling mode of CeO₂ inside the SBA-15 mesopores. A high dispersion of CeO₂ particles was achieved via DP, whereas the dispersion of CeO₂ prepared by IMP was found to be inhomogeneous and CeO₂ partially blocked the pores. The CO conversion in the water-gas-shift reaction was enhanced over 1 wt% Pt supported on CeO₂-modified SBA-15 obtained by DP.     

火焰原子吸收光谱法测定硅粉中的铜

介绍了用火焰原子吸收法测定工业硅粉中微量铜的具体方法和过程，同时也给出了最佳实验条件。实验中采用新的样品处理方法，得到了令人满意的结果。其中样品回收率为99．8％—104．0%，相对标准偏差为0．31％—0.38％。本方法在实际应用过程中，简单、快速、     

钛酸铝材料性能及合成工艺

着重介绍了钛酸铝（Al2TiO3）陶瓷的结构、性能和合成工艺，并对今后发展趋势提出了基本观点。     

扩充编码符号的EZW改进算法

为了提高EZW算法的性能,分析发现EZW算法主扫描编码对最高频子带中不重要系数的编码存在冗余,且当重要系数的所有子孙系数都是不重要系数时的编码存在冗余.据此提出了扩充编码符号的EZW改进算法,用最高频子带的坐标作为限制条件来减少不重要系数的编码冗余;通过扩充编码符号和赋予原始EZW算法的4个编码符号新的适用范围的方案来减小第二种编码冗余.实验结果表明,本文算法使峰值信噪比提高0.9～2.3dB,从而证实了本文改进算法的有效性.     

Effective prediction of DEA model by neural network

In this paper,a fast neural network model for the forecasting of effective points by DEA model is proposed,which is based on the SPDS training algorithm.The SPDS training algorithm overcomes the drawbacks of slow convergent speed and partially minimum result for BP algorithm.Its training speed is much faster and its forecasting precision is much better than those of BP algorithm.By numeric examples,it is showed that adopting the neural network model in the forecasting of effective points by DEA model is valid.     

AADL 测试模型的构造研究

目前,结构分析和设计语言AADL在任务关键嵌入式系统领域有着良好的应用.为了保障任务关键软件的质量,文章提出基于AADL测试模型对AADL设计模型进行测试,以发现设计模型中存在的错误.研究给出了体现系统拓扑结构的AADL测试模型的形式定义及由AADL构造该测试模型的算法,基于该测试模型可以对AADL设计模型中构件交互的输入、输出端口序列和连接的正确性进行测试,并以飞行控制系统的AADL设计模型为例,阐释了研究成果.     

五氯酚在厌氧生物体系中的降解及反馈作用

为探讨厌氧系统降解五氯酚(PCP)能力及PCP对厌氧系统的毒性影响,采用UASB反应器进行了PCP模拟污水连续流试验,考察了不同PCP浓度及负荷条件下系统对PCP和COD的降解去除规律,揭示了PCP对系统产酸相和产甲烷相影响状况.结果表明,在进水PCP含量从无到开始加入、PCP浓度提高以及PCP负荷提高3个冲击变化阶段,厌氧系统对PCP和COD的去除率均表现出先迅速降低后缓慢升高的变化趋势,运行稳定后PCP和COD的去除率分别达91.2%和83.5%以上.PCP对厌氧系统中微生物种群产生影响,使系统产酸菌由丁酸型菌群为主逐渐演替为丙酸型菌群为主,PCP对系统产甲烷菌活性产生明显抑制,甲烷产量由PCP加入前的12.1L/d降低至加入后的2.5L/d.     

凝胶色谱法表征我国几种有代表性超滤膜的截留率——分子量曲线

本文考察了凝胶色谱法的操作压力和进料流速的影响。对国内具有代表性的几种平板超滤膜(聚砜、聚砜酰胺、醋酸纤维素、聚丙烯腈、聚氯乙烯)以及聚砜中空纤维超滤膜的截留率——分子量曲线进行了测定。并给出它们的切割分子量数据。     

Non-Fourier heat conduction in a thin gold film heated by an ultra-fast-laser

Based on the dual-phase-lagging(DPL)heat conduction model,the Cattaneo-Vernotte(CV)model and the improved CV model we investigate the one-dimensional heat conduction in gold films with nano-scale thickness exposed to an ultra-fast laser heating.The influence of system parameters on the temperature field is explored.We find that for all the non-Fourier heat conduction models considered in this work,a larger Knudsen number normally leads to a higher temperature.For the DPL model,the large ratio of the phase lag of temperature gradient to the phase lag of heat flux reduces the maximum temperature and shortens the time for the system to reach its steady state.The CV model and the improved CV model lead to the similar thermal wave behavior of the temperature field,but the thermal wave speeds for these two models are different,especially for large Knudsen numbers.When the phase lag of temperature gradient is smaller,the difference between the DPL model and the improved CV model is not significant,but for the large phase lag of temperature gradient the difference becomes quite significant,especially for the large Knudsen number.In addition,the effect of the surface accommodation coefficient,which is a parameter in the slip boundary condition,on the temperature field of the gold film heated by ultra-fast laser pulses is investigated based on the DPL model.