共面波导馈电的带阻UWB天线设计

提出了共面波导(CPW)馈电平面圆形单极子带阻超宽带(UWB)天线的设计方法,采用该方法设计的天线满足超宽带无线通信所要求的3.1 GHz~10.6 GHz的频带范围,通过在圆形贴片上添加U形和弧形缝隙,可分别实现4.75 GHz~5.96GHz范围内和4.8 GHz~6.2 GHz范围内电压驻波比VSWR≥2的带阻特性,均避免了5 GHz无线局域网的干扰。采用电磁仿真软件CST进行了天线的方向图绘制,仿真结果表明该设计可行。     

左手材料电磁散射特性的仿真研究

分别采用电磁场仿真软件CST MWS和CADFEK0仿真计算了不同电尺寸右手材料和左手材料介质球的电磁散射特性,并对电磁散射数值进行分析,同时与Mie理论计算结果相比较,可得出以下结论:无论在仿真电小尺寸还是电大尺寸的目标时,CADFEK0仿真效果部比CST MWS更佳.最后用CADFEKO软件仿真了金属球涂覆右手材料...     

基于微带传输线的生物溶液处理用纳秒脉冲电场发生器研制

研究纳秒脉冲电场生物学效应需要相应的高压纳秒脉冲发生器。为此,基于微带传输线与固态开关技术,通过波传播过程分析阐释了Blumlein型微带传输线方波的形成原理;采用CST微波实验室仿真分析了微带传输线充电过程中的电场分布;制作了小型化的纳秒脉冲发生器样机,并搭建测试系统对其进行了性能测试。结果表明,在电转杯负载端得到的纳秒脉冲电压幅值在0~2 k V内可调(即对间隙距离为1 mm的电转杯负载,电场强度在0~20 k V/cm内可调),脉宽为100 ns,上升沿约为20 ns,重复频率在0~1 k Hz内可调。     

FENTON AND FENTON-LIKE AOPs FOR ALUM SLUDGE CONDITIONING: EFFECTIVENESS COMPARISON WITH DIFFERENT Fe2+ AND Fe3+ SALTS

Currently, organic polymers are adopted in alum sludge (aluminum-coagulated drinking water treatment sludge) conditioning. However, there are important concerns regarding the use of these polymers because of the unknown and long-term effects of the potential release of excess polymer to the surrounding environment when the sludge is landfilled. Therefore, as an initial action, this study aimed at investigating alternative chemical conditioning methods and focused mainly on exploiting Fenton (Fe²⁺/H₂O₂) and Fenton-like (Fe³⁺/H₂O₂) reagents as the conditioner. Experiments have been conducted to test the effectiveness of Fenton's reagent (containing the ferrous salts of chloride, sulfate, or oxalate), Fenton-like reagent (containing ferric salts of chloride and sulfate), and the coagulation method using FeCl₃ for alum sludge conditioning at constant hydrogen peroxide and iron salt concentrations of 125 and 20 mg/g DS (dry solids), respectively. The effectiveness on dewaterability of the alum sludge demonstrated that the maximum reduction (%) of SRF (specific resistance to filtration) and CST (capillary suction time) of 74% and 47%, respectively, can be obtained when Fenton's reagent was adopted for sludge conditioning. Such reduction of 64% for SRF and 38% for CST can be achieved when Fenton-like reagents were applied.     

Rates of Exchange of Cs+ and Sr2+ for Poorly Crystalline Sodium Titanium Silicate (CST) in Nuclear Waste Systems

The compound sodium titanium silicate, popularly known as CST, is highly selective for Cs⁺. It was synthesized for the purpose of removing ¹³⁷Cs from basic nuclear waste systems. This compound has a tunnel structure in which the Cs⁺ ion just fits but diffusion through the tunnels is relatively slow. CST loses its ability to sequester Cs⁺ in the strongly basic nuclear waste solutions. However, replacement of titanium with 25 mol% of niobium increases the selectivity to a satisfactory level. It has been found that producing a less crystalline form of Nb-CST greatly improves the rate of Cs⁺ removal. Additionally, the non-niobium CST is selective for strontium both as Sr²⁺ and Sr(OH)⁺. It is suggested that both radioisotopes of cesium and strontium may be efficiently extracted by a combination of a mixture of poorly crystalline CST and Nb-CST.     

基于复合左右手传输线结构的小型天线

通过将天线谐振在零阶模式,以及在地平面增加细长线的方法设计了一款基于复合左右手传输线的小型天线,并利用仿真软件CST对该天线的特性进行了仿真验证。结果表明:天线的物理尺寸仅为23 mm×21 mm×1.8mm(0.188λ0×0.171λ0×0.015λ0),天线的零阶谐振频率为2.448 GHz,–10 d B回波损耗阻抗带宽达97.8 MHz,相对带宽达到4.0%,最大增益为2.451 d Bi。所设计的天线具有尺寸小,结构简单、频带宽,增益高等优点,能够满足无线局域网(2.4~2.483 5 GHz)的要求,有广阔的应用前景。     

粒子群算法在三维微带阵列优化设计中的应用

采用粒子群算法与微波仿真软件CST联合仿真的方法,针对拓展吸波带宽或降低吸波材料厚度的不同要求,通过设计不同的适应度函数,实现了对三维微带线阵列吸波结构材料的优化设计。设计结果表明,经过优化设计,吸波材料的吸波带宽可以增加30%,或在吸波性基本不变的条件下材料厚度减少15%。调节适应度函数中的权重,还可以有针对性地拓展吸波材料的频率低频段或高频段。所采用的计算流程可以全程自动进行优化处理。     

SLC500可编程逻辑控制器在煤矿运输中的应用

介绍了A-B公司的SLC500在神华集团神东矿区运输系统的实际应用,SLC产品的先进功能与可靠性,高产高效提供了保障。     

基于步态的身份识别

步态就是个体的行走方式，它作为一种适用于非接触式远距离身份识别的生物特征近来倍受关注。文章提出了一种简单有效的利用行人的步态特征识别身份的算法。对于每个序列而言，行人的重心偏移量首先被用来去除序列中的冗余图像帧；然后，从图像中提取二值化人体轮廓的宽度信息，通过对其进行特征空间变换和规范空间变换来获得可分类的低维步态特征；标准的模式分类技术用于最终的识别。     

可控起动传输系统(CST)技术初探

分析了可控起动传输系统的技术状况、主机的结构、工作原理及其运行速度和传递力矩特性,并对其配套系统、控制管理以及该技术的应用前景作了简略的介绍。