影响挠性印制板插入损耗的几种因素

文章采用三层板叠构对高频通信用挠性印制板(FPCB)的插损进行测试对比,从制造FPCB的材料种类、材料厚度、胶层厚度、仿真设计、信号线过孔类型、盲孔质量,以及信号线阻抗值大小等多个因素总结出对最高频率到20GHz信号插损的影响.     

L波段高功率线极化径向线阵列天线理论分析与数值模拟

 探索了L波段的高功率线极化径向线阵列天线。基于三角形栅格形式实现了径向线圆形平面阵列天线,分析并给出了径向线并联馈电网络,并以同轴馈电的水平单圆环线极化天线为基础,利用径向线并联馈电网络设计出了间距小于一个波长下L波段高功率线极化径向线阵列天线。研究结果表明：这种结构实现径向线阵列天线的线极化辐射是可行的,该天线在中心频率1.57 GHz下,增益为19.97 dBi,轴比为-52.06 dB,反射系数为0.105 2;在1.37～1.77 GHz的频率范围内增益大于18.64 dBi,轴向轴比值小于-46.45 dB。     

Improvement of amine-modification with piperazine for the adsorption of CO2

Both selectivity and capacity of CO₂ adsorption were considerably increased when PZ (piperazine) was added in MDEA (methyldiethylamine) that used to modify the surface of silica gels. The adsorbent saturated with CO₂ was regenerated at ambient temperature through nitrogen purge. A set of PSA (pressure swing adsorption) operation with 200 cycles was carried out and applicability of the modified adsorbent was thus illustrated. The CO₂ content in the column-top stream decreased from 13% to below 0.05% at steady state.     

一种蓝色聚合物激光材料

聚合物作为一种有机发光材料,由于在平板显示和光电子器件中的良好应用前景而受到广泛研究［１～２］．近年来,一个重要进展是在聚合物中观测到了受激发射（简称Ｐｏｌｙ－ｍｅｒ激光）现象［３～６］．Ｐｏｌｙｍｅｒ激光最早是在溶液中实现的［３～４］．作为一种新型...     

声光栅正弦结构光投射器的光学系统设计

针对一种新型的声光波干涉测量技术,对声光栅正弦结构光投射器的三维测量工作原理进行了系统的分析,讨论了影响投射器光学系统结构的因素和影响接收屏上的光照度的因素,并进行了光学系统设计。在优化设计过程中,采用了限制光线最大入射角的方法,达到控制投射系统的球差和保证接收屏上照明均匀的要求。所设计的声光栅正弦光投射器具有很好的成像质量。应用该系统对在500mm处的石膏像上投射干涉条纹,可以得到能量比较均匀、变形量很小的干涉条纹图,利用该条纹图和相关的算法可以对具有复杂几何形状的物体进行有效的三维测量。     

基于Labview与单片机的LED电子屏幕

目前,LED点阵显示文字图形的控制系统,价格昂贵,功能难以扩展,使用不便。文中对LED电子屏幕的主要控制技术及其应用领域作了简要介绍,针对实际应用需要设计出一种基于Labview与单片机控制的LED电子屏幕。在提出系统整体设计方案基础上详细阐述了由Labview实现UCDOS下字库点阵数据提取方法,并设计出信息编辑与管理系统,论述了LED点阵显示原理及单片机控制系统硬件与软件设计思想。     

Non-Invasive Detection of Anti-Inflammatory Bioactivity and Key Chemical Indicators of the Commercial Lanqin Oral Solution by Near Infrared Spectroscopy

Quality control methods of current traditional Chinese medicine (TCM) preparation is time-consuming and difficult to assess in terms of overall efficiency of the drug. A non-destructive rapid near-infrared spectroscopy detection system for key chemical components and biological activity of Lanqin oral solution (LOS), one of the best-selling TCM formulations, was established for comprehensive quality evaluation. Near infrared spectral scanning was carried out on 101 batches of commercial LOS under the penetrated vial state and traditional state. RAW 264.7 cells were cultured to detect the anti-inflammatory ability of LOS, and the reference concentrations of epigoitrin, geniposide, and baicalin were obtained by HPLC. The quantitative models were optimized by three kinds of variable selection methods. The correlation coefficients of prediction value of the models were greater than 0.94. The system also passed the external validation. The performance of the non-invasive models was similar to the traditional models. The established non-destructive system can be applied to the rapid quality inspection of LOS to avoid unqualified drugs from entering the market and ensure drug effectiveness. The biological activity index of LOS was introduced and predicted by NIRs for the first time, which provides a new idea about the quality control of TCM formulations.     

化学教学中的素质教育

长期以来,人们习惯于把化学教育单纯地看成学科专业化教育,而"仅用专业知识教育人是不够的,通过专业教育,他可以成为一种有用的机器,但并不能成为一个和谐发展的人"(爱因斯坦语),这就要求化学教师在传授化学基础知识、基本技能的同时,充分利用化学知识的文化价值、社会价值和教育价值,积极探索化学教育实现素质教育的方法和途径,使得学生学会做人、学会学习、学会生活、学会劳动、学会健体、学会审美和学会创造.     

Synthesis of laterally substituted bistolane liquid crystals

Methods for synthesizing bistolane liquid crystal materials with lateral methyl and ethyl substituents are presented. Some of the bistolanes are nematic at room temperature. These highly conjugated mesogens exhibit wide nematic ranges, small enthalpies of fusion, high birefringence and modest viscosity. Their potential applications for flat panel displays employing light scattering or Bragg reflection and for infrared optically phased arrays are foreseeable.     

Ag/CNT‐catalyzed hydroamination of activated alkynes with aromatic amines

As a nanoparticle support material, carbon nanotubes (CNTs) provide a certain potential activation of catalysis in heterogeneous catalytic organic reactions. Herein, an efficient Ag/CNT‐catalyzed synthesis of enamines via hydroamination of activated alkynes with aromatic amines has been described. This catalyst still retains catalytic activity after being recycled and reused three times. In addition, it represents a green and environmentally friendly process for preparation of enamines. Copyright © 2013 John Wiley & Sons, Ltd.