实时图像跟踪系统中TMS320C6x DSP的软件优化

TMS320C6x系列DSP器件采用了VelociTI TM体系结构的内核,集成了DMA控制器等多种功能强大的外设,并具有以blocks和banks划分的内部数据存储器.要充分发挥硬件潜力,提高系统性能,就必须采取一系列措施来优化DSP软件,实现指令的高度并行和流畅的流水线操作.文章介绍了TMS320C6x C语言优化方面的一些有效的方法,包括硬件特点考虑,指令存储器相关性消除,以及代码结构改善等.并给出了实时图像跟踪系统中的应用和结果.     

802.1 x协议分析及其应用

本文对802.1x协议体系结构、流程及其工作原理作了分析,然后介绍了基于该协议的各种传统应用,在此基础上对协议的应用作了进一步扩展,将其引入到网关系统的访问控制中,并概要分析了几种网关模式的应用场景,最后把它同其它认证方式作了分析和比较.     

基于PCI总线的高速数据采集系统

介绍一种基于PCI总线的PC机插卡形式的高速数据采集系统。该系统的特点是:由Windows98下的应用程序控制采集,能满足雷达在距离、方位上的开窗采集要求;采集的数据既可用PC机内存作暂存,也可送入其他处理插件;通过运用多通道并列技术,可以并行同时采样4路模拟信号,也可以在串行处理方式下以4倍速率采集1路模拟信号;数据采用PCI总线接口,并配合Windows98的虚拟设备驱动程序,使32bit数据传向PC机的速率达到30MHz。     

用拉曼散射谱与远红外反射谱研究Ga_xIn_(1-x)As_ySb_(1-y)四元混晶的长波光学声子

报道了 MBE外延生长的 Gax In1 - x Asy Sb1 - y四元混晶的拉曼散射谱与远红外反射谱 ,并从拉曼散射谱中观察到了 Gax In1 - x Asy Sb1 - y四元混晶的晶格振动四模行为 ;从实验中还观察到低于 180 cm- 1的若干散射峰 ,提出它们可能是与次近邻原子间相互作用的晶格振动模式有关 ;从拉曼散射谱和红外反射谱中观察到了与 Gax In1 - xAsy Sb1 - y四元混晶多声子吸收过程的有关的现象     

Pencil Drawing Stable Interface for Reversible and Durable Aqueous Zinc-Ion Batteries

Zinc-ion batteries (ZIBs) have been regarded as one of the most promising aqueous energy storage devices due to their low-cost, high capacity, and intrinsic safety. However, the relatively low Coulombic efficiency caused by the dendrite formation and side reactions greatly hinders the rejuvenation of ZIBs. Here, an utterly simple approach by pencil drawing is employed to improve the poor performance of normal Zn anode and hinders the formation of passivated byproduct as well as serious dendrite growth. Significantly, the functional graphite layer can not only act as ions buffer, but also guide the uniform nucleation of Zn²⁺ in graphite voids. With such synergy effect, the graphite-coated Zn anode (Zn–G) displays low overpotential, high reversibility, and dendrite-free durability compared with the pristine Zn. Consequently, a low voltage hysteresis of ≈ 28 mV can be achieved and maintained over 200 h. Furthermore, the Zn–G anode is paired with a V₂O₅·xH₂O cathode to construct a rechargeable ZIB. As-assembled device can output high energy/power density of 324.3 Wh kg⁻¹/3269.8 W kg⁻¹ (based on the active mass loading in cathode) together with a capacity retention of ≈ 84% over 1500 cycles at a current density of 5 A g⁻¹.     

一种基于FPGA的可变速率帧结构设计与实现

在简述V.35接口的基础上针对V.35接口速率可变的应用需求提出了一种速率可变的帧结构,该帧结构可支持N×64kb/s(3≤N≤32)速率,从而在V.35接口上实现了多种速率的低速业务传输.     

A modified rain attenuation prediction model for tropical V‐band satellite earth link

Radio wave propagation plays a very important part in the design and eventually dictates performance of space communication systems. Over time, the requirements of satellite communication have grown extensively where higher capacity communications systems are needed. Escalating demands of microwave and millimetre wave communications are causing frequency spectrum congestion. Hence, existing and future satellite system operators are planning to employ frequency bands well above 10 GHz. The challenge in operating at such high frequencies for communication purposes is that there exists stronger electromagnetic interaction between the radio signals and atmospheric hydrometeors. Such instances will degrade the performance of such high frequency satellite communication systems. The development of a revised model for a better‐improved rain fade prediction of signal propagations in tropical region is considered very important. Researchers and engineers can employ the model to accurately plan the future high frequencies satellite services. Copyright © 2014 John Wiley & Sons, Ltd.     

溅射制备ZnS:Er~(3+)薄膜的光电子发射结构

利用射频磁控溅射法制备掺铒硫化锌直流电致发光薄膜，用ＸＰＳ（ｘ射线光电子能谱）技术进行剖析，获得薄膜内部构态与发光性能关系的信息，讨论了微晶薄膜中稀土掺杂状态对激发机制的影响。     

Si_（1－x）Ge_x／Si定向耦合器的研制

在运用ＳｉＧｅ脊形波导单模条件和有效折射率法分析ＳｉＧｅ／Ｓｉ定向耦合器结构参数的基础上，采用分子束外延和各向异性腐蚀技术制备出Ｓｉ１－ｘＧｅｘ／Ｓｉ（ｘ＝０．０５）单模定向耦合器．在波长为１．３μｍ时，平均串音小于－１８．１ｄＢ，输出功率耦合效率达到９８．１％     

无线局域网入侵检测系统的设计

无线局域网入侵检测系统(WIDS)架构由管理中心、代理、接入点和工作站4个实体组成.WIDS是基于客户机/服务器模式,管理中心是客户端,遍布于网络中的代理是服务器.每个接入点的服务范围构成1个小区.该系统在802.1x增强性解决方案基础上,增加1台微机作为代理,对网络中的假冒接入点和混杂模式节点进行检测,以杜绝802.1x方案中的中间人攻击和会话劫持攻击.