双脊型波导窗在宽带大功率行波管中的应用

本文简要分析了脊形波导窗的结构,介绍了WRD650双脊波导窗在实际制管中的应用,测试结果表明脊形波导窗应用于宽带大功率行波管是可行的.     

Influence of La substitution on the electrical properties of metal-ferroelectric (BiFeO3)-insulator (CeO2)-semiconductor nonvolatile memory structures

Metal-multiferroic (La-substituted BiFeO₃)-insulator (CeO₂)-semiconductor (MFIS) capacitors has been fabricated. The crystalline phase and amount of La³⁺ substitution at Bi-site were investigated by XRD and XPS in the postannealing temperature range from 500 to 700 °C, respectively. The microstructure and interfacial layer between CeO₂ and Si substrate were characterized by HRTEM. The memory windows as functions of insulator film thickness and DC power for La were measured. The maximum memory window is about 1.9 V under ±6 V applied voltage. The ferroelectric polarization increases with increasing substitution amount. The morphologies of La-substituted BiFeO₃ films were also studied by AFM.     

基于移动窗口的图像缩放算法

针对传统双线性插值法在缩小时需要预缩放,硬件实现复杂,成本高,提出了改进的基于移动窗口的缩放算法,其实现简单,成本低.用Matlab前期仿真表明缩放效果好.并对LED屏的"比例缩放"工程问题,详介了FPGA设计过程,给出了后期验证方案.     

A Novel Approach to BaTiO3-based X8R Ceramics by Calcium Borosilicate Glass Ceramic Doping

High-performance X8R dielectric materials could be sintered at 1150°C by doping calcium borosilicate (CBS) glass ceramic into the BaTiO₃-Nb₂O₅-ZnO system, with a dielectric constant greater than 1800 and a dielectric loss lower than 1.0%. The effects of CBS, Nb₂O₅, and ZnO on the dielectric properties were discussed in this article. The X8R specification was achieved with the content of CBS ≥ 4 wt.%, Nb₂O₅ ≥ 1.0 mol%, and ZnO ≤ 2.0 mol%. The sample doped with 4 wt.% CBS exhibited the highest density and lowest dielectric loss in our experiment. A reduction in grain size was observed in the specimens with 4 and 7 wt.% CBS as compared with CBS-free specimen, whereas the abnormal growth of rectangle-shaped grains took place in the 10 wt.% CBS-doped specimen. The Curie point progressively moved to higher temperatures with CBS content up to 7 wt.%. However, T _c of the sample decreased slightly in the case when 10 wt.% CBS was doped. X-ray diffraction (XRD) analysis indicated that the crystal structure of sintered ceramics changed from tetragonal to pseudocubic symmetry as increasing CBS content.     

数字电位器在功率自适应控制中的应用

X9312W是Xicor公司生产的一种典型的数字电位器,文中介绍了它在功率自适应控制系统中的应用,重点说明了应用中如何处理X9312W的电压与脉冲计数的关系及控制电压与输出功率之间的控制关系,并给出了数字电位器的控制程序。     

基于STL转换为X3D格式的研究与实现

通过对STL三角网格模型和X3D语法规范的分析与研究,根据X3D对三角形的相关定义和描述,提出了一种将STL三角网格模型转换为X3D格式的算法。该算法在实现将STL转化为X3D的同时,又完成了对STL文件中冗余数据的处理,使得转换后的X3D文件大小相当于原来STL文件大小的1/7左右,非常有利于三角网格模型在网络上的传输和操作。最后,以Java作为开发系统平台,运用Java3D及其装载器组件实现了转换后的X3D的装载和浏览,从而使STL文件可以在Internet环境下实现产品信息共享和可视化的操作。     

Improvement of the cell performance in the ZnS/Cu(In,Ga)Se2 solar cells by the sputter deposition of a bilayer ZnO : Al film

ZnS is a candidate to replace CdS as the buffer layer in Cu(In,Ga)Se₂ (CIGS) solar cells for Cd‐free commercial product. However, the resistance of ZnS is too large, and the photoconductivity is too small. Therefore, the thickness of the ZnS should be as thin as possible. However, a CIGS solar cell with a very thin ZnS buffer layer is vulnerable to the sputtering power of the ZnO : Al window layer deposition because of plasma damage. To improve the efficiency of CIGS solar cells with a chemical‐bath‐deposited ZnS buffer layer, the effect of the plasma damage by the sputter deposition of the ZnO : Al window layer should be understood. We have found that the efficiency of a CIGS solar cell consistently decreases with an increase in the sputtering power for the ZnO : Al window layer deposition onto the ZnS buffer layer because of plasma damage. To protect the ZnS/CIGS interface, a bilayer ZnO : Al film was developed. It consists of a 50‐nm‐thick ZnO : Al plasma protection layer deposited at a sputtering power of 50 W and a 100‐nm‐thick ZnO : Al conducting layer deposited at a sputtering power of 200 W. The introduction of a 50‐nm‐thick ZnO : Al layer deposited at 50 W prevented plasma damage by sputtering, resulting in a high open‐circuit voltage, a large fill factor, and shunt resistance. The ZnS/CIGS solar cell with the bilayer ZnO : Al film yielded a cell efficiency of 14.68%. Therefore, the application of bilayer ZnO : Al film to the window layer is suitable for CIGS solar cells with a ZnS buffer layer. Copyright © 2012 John Wiley & Sons, Ltd.     

640×512焦平面读出电路设计

介绍了640×512电容反馈跨阻放大器(CTIA)型焦平面读出电路的设计,包含模拟电路与数字模块设计。分析了CTIA采样单元的设计,折中优化了采样单元的面积、噪声、增益等因素,同时优化了采样单元控制电路,最大限度地提高了对采样单元阵列的驱动能力;数字控制部分着重分析了对行选、列选、翻转读出、随机开窗、隔行扫描、多路选择输出等功能的实现方式。设计基于0.5μm DPTM工艺进行仿真验证,采样单元面积为25μm×25μm,工作频率为5MHz,芯片面积为18.1mm×17.4mm,输出摆幅大于2.5V,动态范围大于70dB。     

Microstructure evolution and corrosion resistance in simulated CGHAZ of X80 high-deformability pipeline steel

In this study, the microstructure evolution and corrosion resistance in 0.5M Na₂CO₃-1 M NaHCO₃ solution of X80 high-deformability (X80HD) pipeline steel coarse-grained heat-affected zone (CGHAZ) with several heat input levels were investigated. It is shown that the microstructure of CGHAZ changes from bainite ferrite to granular bainite as the heat input increasing. In addition, the corrosion resistance and the stability of passive film of base material are better than those of CGHAZ with several heat input levels. Too small or too big heat input is inadvisable and better corrosion resistance of CGHAZ is attained when heat input is 30kJ/cm.     

Voltage-to-frequency converter with high sensitivity using all-MOS voltage window comparator

A high-sensitivity voltage-to-frequency converter (VFC) using an all-MOS voltage window comparator is presented in this work. The circuit is composed of one voltage-to-current converter, one charge and discharge circuit, and one all-MOS voltage window comparator. The input voltage is converted into a current which in turn triggers the charge and discharge circuit, where a built-in capacitor is driven. The voltage window comparator monitors the variated voltage on the capacitor and generate an oscillated output of which the vibration frequency is linearly dependent to the input voltage. In this way, the worst-case linear range of the output frequency of the proposed VFC is 0-55.40 MHz verified by simulations given a 0-0.9 V input range. The physical measurement of the proposed VFC shows a 0-52.95 MHz output frequency given a 0-0.9 V input range. The error in linearity is better than 8.5% while the power dissipation is merely 0.218 mW.