负载型贵金属纳米粒子作为光/超声催化剂在化学合成和降解污染物方面的应用

综述了Au/TiO2、Au/ZrO2、Ag/AgCl等负载型贵金属纳米粒子作为有效的光/超声催化剂在化学合成和降解污染物方面的应用.负载型贵金属纳米粒子能够有效地将太阳能转化为化学能.在紫外光或可见光的辐照下,负载型贵金属纳米粒子能够催化一系列的选择性化学转化,如醇类化合物氧化为醛/酮类化合物、硫醇氧化为二硫化合物、苯氧化为苯酚、硝基苯类化合物还原为偶氮化合物等.在超声波辐射下,负载型贵金属纳米粒子能够有效地催化分解水产氢.此外,在紫外光或可见光的辐照下,负载型贵金属纳米粒子能够有效地催化降解多种污染物,如醛类、醇类、酸类、酚类化合物和染料等.在超声波辐射下,负载型贵金属纳米粒子也能够有效地催化降解包括染料在内的有机污染物.     

反相高效液相色谱法测定肾复康胶囊中的野黄芩苷和芦丁

建立了肾复康胶囊中野黄芩苷和芦丁的反相高效液相色谱测定方法。以甲醇-水为提取溶剂,采用超声提取法对样品进行前处理。以0.02 mol/L磷酸二氢钾缓冲溶液(含1.0％（体积分数）冰醋酸)-甲醇（体积比为63∶37）为流动相,于330 nm波长下检测,肾复康提取液中野黄芩苷和芦丁可达基线分离,分析时间在20 min内。野黄芩苷和芦丁在10 ~300 mg/L内,其峰面积与浓度之间线性关系良好,目标物的加标回收率大于98％。该方法适用于肾复康胶囊及相关药材中野黄芩苷和芦丁黄酮类化合物的测定和质量控制。     

中英高中物理教材中关于电场内容的比较

针对学生在电场学习中的障碍,借鉴和比较中英两国在电场内容上的不同处理,从教学实践和教材编写方面提出意见.     

基于双周期锯齿波LFMCW的距离速度去耦合

采用发射双周期锯齿波并结合MTD处理的方式,实现了LFMCW雷达距离与速度的解耦合。其中,针对多目标场景下的目标配对问题,提出了耦合距离目标配对法。并通过对配对后的目标进行速度解模糊,进而解算出其真实运动参数。仿真结果证明了整个处理流程及配对算法的有效性。     

Deposition Behavior and Mechanism of Ni Nanoparticles on Surface of SiC Particles in Solution Systems

Ni-deposited SiC particles are prepared successfully by a facile chemical reaction approach. The structure and morphology analyses demonstrate the Ni nanoparticles have been deposited on the surface of SiC particles. The deposition behavior of Ni on the surface of SiC particles is investigated. Pd-Sn catalytic nuclei formed in the pretreatment process promote the redox reaction and lead to the reduction of Ni^2＋ to metal nickel. Moreover, the kinetic mechanism of the reaction process of Ni%2＋ and H2PO^-2 has also been discussed in detail. Kinetic models have been established.     

基于零频抑制与杂波图的地面慢速目标检测

强地物杂波严重影响雷达系统对慢速目标的探测性能,对此设计了基于零频抑制与杂波图的地面慢速目标检测方法。采用Kalmus滤波器提高零频抑制能力,并针对慢速目标检测的实际需求,对其滤波性能和设计方法进行了分析。采用空间邻域插值方式完成目标区域的杂波背景积累,解决慢速目标检测不连续问题。最后对改进的慢速目标检测方法进行了仿真分析。实验结果表明,该方法对地面慢速目标的检测概率优于其他方法。     

混沌二相码脉冲压缩性能分析

编码信号是多普勒敏感信号,回波多普勒频移的存在会导致编码信号的脉冲压缩性能下降。文中从积分旁瓣比以及信噪比损失两方面分析了多普勒频移对混沌二相码信号压缩性能的影响,并通过仿真验证了分析的正确性。     

Microwave Absorbing Materials： Solutions for Real Functions under Ideal Conditions of Microwave Absorption

We present general equations for metal-substrate single-layer microwave absorbing materials. The optimum electromagnetic parameters and matching thicknesses for electric-loss, magnetic-loss, and electromagnetic-loss materials are given, and possible solutions for the equations and the corresponding theoretic curves are discussed as well. The results may be helpful for designing high-performance microwave absorbing materials.     

Carbon materials with quasi-graphene layers: the dielectric, percolation properties and the electronic transport mechanism

We investigate the dielectric properties of multi-walled carbon nanotubes (MWCNTs) and graphite filling in SiO₂ with the filling concentration of 2-20 wt.% in the frequency range of 10²-10⁷ Hz. MWCNTs and graphite have general electrical properties and percolation phenomena owing to their quasi-structure made up of graphene layers. Both permittivity ε and conductivity σ exhibit jumps around the percolation threshold. Variations of dielectric properties of the composites are in agreement with the percolation theory. All the percolation phenomena are determined by hopping and migrating electrons, which are attributed to the special electronic transport mechanism of the fillers in the composites. However, the twin-percolation phenomenon exists when the concentration of MWCNTs is between 5-10 wt.% and 15-20 wt.% in the MWCNTs/SiO₂ composites, while in the graphite/SiO₂ composites, there is only one percolation phenomenon in the graphite concentration of 10-15 wt.%. The unique twin-percolation phenomenon of MWCNTs/SiO₂ is described and attributed to the electronic transfer mechanism, especially the network effect of MWCNTs in the composites. The formation of network plays an essential role in determining the second percolation threshold of MWCNTs/SiO₂.     

肝生素治疗40例重型乙型病毒性肝炎的疗效初探

应用肝生素治疗各种重型乙型病毒性肝炎,结果表明,４０例重型乙型病毒肝炎患者经肝生素治疗,治疗组死亡１５例,病死率３７．５％,对照组死亡２６例,病死率６５．０％,两组比较有显著差异。肝生素在重型肝炎的早中期治疗效果特别理想,可认为肝生素是目前治疗重型病毒性肝炎比较理想的护肝药物。