光纤喇曼放大器的功率转换效率分析

在定义光纤喇曼放大器(FRA)功率转换效率(PCE)的基础上,考察了不同工作条件下光纤喇曼放大器的功率转换效率,分析PCE与光纤喇曼放大器的输入信号功率、输入泵浦功率和光纤长度的关系,比较了分布式与集总式FRA的功率转换效率,给出提高FRA功率转换效率的途径。     

基于新型高速高集成度单片机C8051F060的智能功率柜

简要介绍了智能励磁功率柜的概念及C8051F060单片机的特点 ,详细论述了基于C8051F060的智能励磁功率柜的结构、原理以及与CAN总线通信的实现方法。该控制方案系统集成度高、硬件简单、工作可靠 ,具有很好的推广价值     

基于智能相机的高速三维表面信息获取

为了大幅度提高三维信息获取速度,提出了一种基于智能相机和激光三角法的高速三维信息获取与表面重建的系统,介绍了该系统的硬件架构和信号处理。实验结果表明,采用数字信号处理器和并行处理方式,该系统获取三维表面信息速度可达5600点/s以上。     

高功率850 nm宽光谱大光腔超辐射发光二极管

超辐射发光二极管(SLD)具有不同于半导体激光器和普通发光二极管的优异性能。为提高半导体超辐射发光管的光谱宽度,采用非均匀阱宽多量子阱(MQW)材料拓宽超辐射器件的输出光谱。优化设计器件的波导结构,利用大光腔结构设计出高功率、低发散角850 nm超辐射发光二极管。采用直波导吸收区而后在器件的出光腔面上镀制抗反射膜的方法制作超辐射发光二极管。器件在140 mA时器件半峰全宽(FWHM)可以达到26 nm,室温下连续输出功率达到7 mW。器件的垂直发散角为28°,水平发散角为10°。由于器件具有比较小的发散角,与光纤耦合时具有比较高的耦合效率,单模保偏光纤耦合输出功率达到1.5 mW。     

基于Cortex-M3的TFT屏在车距信号采集系统中的应用

探讨了一种基于Cortex-M3内核芯片的TFT屏显示汽车距离的系统,论述了系统的工作原理、硬件结构和软件流程,以毫米波FMCW调频连续波雷达作为数据的收发模块并通过DSP对数据进行准确有效的处理。可以检测前方目标的距离并实时显示到TFT屏上且会有三个参考图片来直观的表示距离在动态变化,当超过设定的安全值时可以及时起到提醒驾驶员的作用,降低交通事故的发生率。     

H型栅结构的亚微米PDSOI MOS器件的跨导双峰效应研究

A bimodal effect of transconductance was observed in narrow channel PDSOI sub-micron H-gate PMOSFETs,which was accompanied with the degeneration of device performance.This paper presents a study of the transconductance bimodal effect based on the manufacturing process and electrical properties of those devices.It is shown that this effect is caused by a diffusion of donor impurities from the NC region of body contact to the PC poly gate at the neck of the H-gate,which would change the work function differences of the polysilicon gate and substrate.This means that the threshold voltage of the device is different in the width direction,which means that there are parasitic transistors paralleled with the main transistor at the neck of the H-gate.The subsequent devices were fabricated with layout optimization,and it is demonstrated that the bimodal transconductance can be eliminated by mask modification with NC implantation more than 0.2 m away from a poly gate.     

一种基于检测信息可靠度的部分软干扰消除迭代多用户检测算法

该文提出了一种基于检测信息可靠度的部分软干扰消除迭代多用户检测算法。如果由从信道译码器所获得的发送字符的先验信息大于某一预定阈值,则认为对其检测具有较高的可靠度,因而可以考虑将其对应的多址干扰成分从匹配滤波器输出向量中直接消除,相当于减小了干扰用户的数目,从而可以减小迭代多用户检测算法的复杂度。该算法的计算复杂度能够随着多址干扰的减小和信道信噪比的增大而降低。     

Electrochemically Tuned Properties for Electrolyte‐Free Carbon Nanotube Sheets

Injecting high electronic charge densities can profoundly change the optical, electrical, and magnetic properties of materials. Such charge injection in bulk materials has traditionally involved either dopant intercalation or the maintained use of a contacting electrolyte. Tunable electrochemical charge injection and charge retention, in which neither volumetric intercalation of ions nor maintained electrolyte contact is needed, are demonstrated for carbon nanotube sheets in the absence of an applied field. The tunability of electrical conductivity and electron field emission in the subsequent material is presented. Application of this material to supercapacitors may extend their charge‐storage times because they can retain charge after the removal of the electrolyte.     

Public key cryptography based privacy preserving multi-context RFID infrastructure

In this paper, we propose a novel radio frequency identification (RFID) infrastructure enabling multi-purpose RFID tags realized by the use of privacy preserving public key cryptography (PKC) architecture. The infrastructure ensures that the access rights of the tags are preserved based on the spatial and temporal information collected from the RFID readers. We demonstrate that the proposed scheme is secure with respect to cryptanalytic, impersonation, tracking, replay, and relay attacks. We also analyze the feasibility of PKC implementation on passive class 2 RFID tags, and show that the requirements for PKC are comparable to those of other cryptographic implementations based on symmetric ciphers. Our numerical results indicate PKC based systems can outperform symmetric cipher based systems, since the back end servers can identify RFID tags with PKC based systems approximately 57 times faster than the best symmetric cipher based systems.     

空间一致性邻域保留嵌入的高光谱数据特征提取

局部线性嵌入(LLE)和邻域保留嵌入(NPE)等流形学习方法可以提取高光谱数据的主要结构特征,有助于对数据的理解和进一步处理。但是,这些方法忽视了高光谱图像中相邻像素之间的相关性。针对这个问题,提出一种基于空间一致性思想的邻域保留嵌入(SC-NPE)特征提取算法,通过一个优化的局部线性嵌入,并考虑相邻像素的相关特性,在高维空间建立数据的局部邻域结构。然后寻找一个优化的变换矩阵,将局部邻域结构投影到低维空间,实现数据的特征提取。与LLE和NPE算法相比,SC-NPE既考虑高光谱数据的流形结构,又考虑了其图像域空间信息,可以更好地应用在高光谱数据的特征提取过程中。实验结果表明,SC-NPE特征提取算法在高光谱图像分类方面的性能明显优于其他同类算法。