走下云端,安全领航——卫士通安全云计算及应用探索

在云计算和云安全方面,卫士通公司通过大量的研究,形成了一些自己的认知,并推出了一些观点。所谓云计算就是通过整合、管理、调配分布在网络各处的计算资源,形成庞大的资源池,再以统一的模式同时向大量用户提供所需的服务。     

A low power and low phase-noise 91~96 GHz VCO in 90 nm CMOS

This paper reports a 94 GHz CMOS voltage-controlled oscillator (VCO) using both the negative capacitance (NC) technique and series-peaking output power and phase noise (PN) enhancement technique. NC is achieved by adding two variable LC networks to the source nodes of the active circuit of the VCO. NMOSFET varicaps are adopted as the required capacitors of the LC networks. In comparison with the conventional one, the proposed active circuit substantially decreases the input capacitance (C_in) to zero or even a negative value. This leads to operation (or oscillation) frequency (OF) increase and tuning range (TR) enhancement of the VCO. The VCO dissipates 8.3 mW at 1 V supply. The measured TR of the VCO is 91~96 GHz, close to the simulated (92.1~96.7 GHz) and the calculated one (92.2~98.2 GHz). In addition, at 1 MHz offset from 95.16 GHz, the VCO attains an excellent PN of – 98.3 dBc/Hz. This leads to a figure-of-merit (FOM) of ?188.5 dBc/Hz, a remarkable result for a V- or W-band CMOS VCO. The chip size of the VCO is 0.75 × 0.42 mm², i.e. 0.315 mm².     

光纤通信网络传输技术及其应用

光纤通信网络传输技术具有较高的传输速度,通信容量较大,且传输损耗较低,在通信网络传输中具有良好的应用效果。但目前,部分业内人员未对光纤通信网络传输技术形成正确的认知,导致该技术无法在实际应用中发挥自身价值。为解决上述问题,文中通过调查与分析,对光纤通信网络传输技术的应用优势及类型进行了探讨,并对其具体应用进行了分析,以期为从业人员提供一定的启示。     

多星座GNSS接收机设计与实现

GNSS的发展大大增加了导航信号数量,因此开发可接收多个星座信号的GNSS接收机具有很大的意义。本文设计实现了一种简单灵活的新型接收机,主要包括利用MAX2769作为射频前端实现多星座信号覆盖,可重配置的FPGA实现多星座信号的捕获跟踪与数据传输,导航与数据后处理由计算机实现。同时为了兼容多种GNSS信号,设计了通用跟踪环路。测试结果表明设计的GNSS接收机具有体积小、实时性好和兼容性强等特点,满足实际应用需求。     

Different Directions of Switching of Chromium Oxide Thin Films

We have investigated the switching behavior of as-deposited CrO _x and post-annealed CrO _y films by use of a variety of electrodes (top electrode Ag, Ti; bottom electrode Pt, fluorine tin oxide (FTO)). Resistance switching is highly dependent on electrode material and post-annealing treatment. Among Pt devices, I–V hysteresis was observed for the Ag/CrO _x /Pt device only; no resistance switching was observed for Ag/CrO _y /Pt, Ti/CrO _x /Pt, and Ti/CrO _y /Pt devices. Among FTO devices, I–V hysteresis was observed for the Ag/CrO _x /FTO device whereas I–V hysteresis with the opposite switching direction was observed for Ag/CrO _y /FTO, Ti/CrO _x /FTO, and Ti/CrO _y /FTO devices. The direction of switching depends not only on electrode material but also on post-annealing treatment, which affects the density of grain boundaries. Thus, the density of grain boundaries determines the type of charge carrier involved in the switching process. For as-deposited CrO _x films with a high density of grain boundaries Ag filament paths mediated by electrochemical redox reaction were observed, irrespective of bottom electrode material (Pt or FTO). Post-annealed CrO _y films with a low density of grain boundaries suppressed electrochemical redox reaction in the Ag/CrO _y /Pt device but promoted short-range movement of O^2? ions through the bottom interface, resulting in resistance switching in the Ag/CrO _y /FTO device. Electrochemical redox reaction-controlled resistance switching occurred solely in oxides with a high density of grain boundaries or dislocations.     

基于子节点编码和声搜索的QoS组播路由算法

传统启发式方法求解QoS组播路由问题复杂度高,收敛速率慢,无法满足实际需求。该文提出一种基于子节点编码的和声搜索算法以解决该问题。在和声搜索算法的基础上,该算法设计了新的初始解及新解生成方式,提升了算法执行效率;提出了参数动态调整方案,兼顾了全局搜索以及局部搜索能力;同时设计了一种基于子节点的组播树编码方式,加快了新解生成过程。通过理论分析仿真实验,证明了该文算法的低复杂度,表明该文算法在收敛速率和代价方面具有明显优势。     

旋波媒质基本参数的一种测试方法

本文提出了直接利用旋波材料板的Ｓ参数获得其基本参数的方法。通过自由空间测量旋波材料板的反射场和透射场，可以反演得到媒质的复介电常数、复磁导率、旋波量以及透射场的轴比和旋转角，测试程序简单，结果精度高。     

湖北河网地区特高压输电线路工程施工特点分析

通过对湖北河网地区自然地理条件的分析,深入研究河网地区特高压线路施工中的物料运输、基础开挖、基础施工、杆塔组立、施工环境保护等环节的重点与难点,并有针对性提出新型施工设备及工器具的研制要求,为河网地区特高压输电线路施工技术研究提供指导意见。     

基于SDH传输体制的OptiX155／622H组网业务配置

OptiX 155/622H作为一种SDH设备适合于各种规模的电信网络。对SDH的概念、以及OptiX 155/622H设备做简单的介绍,并着重探讨OptiX 155/622H典型连接的业务配置,并对其组网命令行文件书写规范加以注解,用以帮助对命令语句的理解。最后对城域网传输设备的发展趋势做了简要的阐述。     

C波段大栅宽GaAs MESFET的研制

采用高质量的 MBE材料 ,成功地制作了单胞栅宽 2 0 mm的芯片。用栅与 n+凹槽自对准和辅助侧墙工艺制作了栅长 0 .45 μm的 Ti Pt Au栅 ,欧姆接触采用 Au Ge Ni合金工艺 ,采用 PECVD Si N钝化 ,空气桥结构及芯片减薄 Via-Hole工艺。经内匹配得到了单胞芯片 3.7～ 4.2 GHz下 Po≥ 7.3W,Gp≥ 8d B,ηadd>2 5 % ;4胞合成器件 Po≥ 2 5 W,Gp>7d B,ηadd>2 5 %的良好结果。