远程预警相控阵雷达资源调度仿真研究

在分析远程预警雷达工作方式和资源调度设计原则的基础上，提出了一种仿真实现自适应资源调度的方法，并给出了仿真实现的详细流程。该方法能够根据雷达事件的优先级、驻留长度以及期望发射时间合理的安排雷达事件，仿真结果验证了该方法的有效性。     

基于nRF2401的腕带式电子标签设计

提出一种新的基于nRF2401射频芯片和MSP430单片机的腕带式有源电子标签设计,包括硬件匹配电路设计、天线设计以及软件编程设计。该有源电子标签工作于2.45GHz,采用内设丰富且功能强大的无线收发模块nRF2401作为射频前端,外围电路极少,满足腕带式电子标签体积小的设计要求;采用低功耗高性能的MSP430单片机作为微控制器,数据处理速度快并且兼顾低功耗的要求。测试结果证明,该标签整体性能稳定,抗干扰能力强,工作距离可达70m。     

介质目标的太赫兹波近场散射特性计算

该文基于广义的Kirchhoff阻抗边界条件和物理光学法,对太赫兹频段介质体近场散射特性进行了研究,给出了介质体近场散射计算公式。针对在太赫兹频段由于波长较短引起的计算量大幅提升的问题,采用以面元为计算单位、以像素为遮挡判断单位的太赫兹频段介质体近场散射的快速计算方法,该方法在保证计算精度的基础上,大大降低了计算复杂度和时间。计算了圆柱体和鸭嘴形介质体在不同距离下的雷达散射截面,并且分析了电磁场与物体相互作用后,相位项在不同距离、不同频率下对介质体雷达散射截面的影响。     

End-to-End Rate Adaptation to Support Heterogeneous Services for Infrastructure-Based Vehicular Networks

Vehicle to Infrastructure(V2I) communications aim to provide mobile users on the road low-cost Internet and driver safety services.However, to meet Quality of Service(QoS) requirements of various applications and efficiently utilize limited wireless channel resourc-es, the transport layer protocol has to perform effective rate control in low channel quality and frequent changing topology communica-tion environment. In this paper, we propose a novel rate-control scheme in infrastructure based vehicular networks that avoids conges-tion and starvation and promotes fairness in end-to-end V2I communications. In vehicular networks, a bottleneck roadside unit(RSU)keeps track of its buffer size, aggregate incoming rate, and link throughput, and appropriately allocates bandwidth to traversing flows.With feedback information from the RSU, source nodes dynamically adjust their sending rates to avoid buffer overflow or starvation atthe bottleneck RSU. Simulation results show that the proposed scheme can reduce not only packet losses owing to buffer overflow butalso buffer starvation time, which improves the utilization efficiency of wireless channel resource.     

在PPT课件中嵌入视频文件的制作技巧

在PPT课件中使用普通方法链接的视频,如果把视频源文件删除后,链接到PPT课件中的视频就无法播放了.本文通过把视频文件转换成.swf格式大件,再利用Shockwave Flash Object控件,把.swf格式文件嵌入到PPT课件中,真正实现了视频大件的嵌入.     

网络经济下开源运动的抉择探析

从寡头垄断市场结构角度来分析开源运动现象存在的内在实质原因，并对开源后的寡头领先企业和跟随企业对市场规模的影响和企业的决策行为选择进行深入分析，并对在这种环境下的各自的优势和劣势进行了对比分析，指出了对中国企业的借鉴作用。     

水下航行器试验航路设计与仿真

水下航行器的导航精度试验与航路的设计关系密切,为了找出最佳的试验航路,以得到真实可信的导航精度,该文通过对导航系统采用多普勒计程仪加光纤陀螺罗盘或惯导系统的仿真,分别计算直线航路、闭环航路和开环航路情况下的导航精度,以确定不同航路设计对导航精度的影响。仿真结果表明,由于导航系统的误差在环形航路中会互相抵消,使得环形航路试验得到的导航精度偏小,这与试验的本意相违背;而直线航路试验不受此影响,得到的导航精度较环形航路的大,是最接近真值的。本文首次提出了用仿真计算确定水下航行器试验航路的方法,可为水下航行器试验航路的选择提供依据。     

闭锁式接电开关接触可靠性改进措施

闭锁式接电开关在应用中有时会出现不能闭合的现象,为了提高其工作可靠性,对开关零部件中惯性销和内接电片的结构进行了改进,采取了增加惯性销质量、在惯性销的底部两侧开透气槽、改善惯性销头部圆锥角度、减小内接电片支耳宽度等措施,经过仿真与试验,验证了上述改进措施的有效性,改善了内接电片受力状态,有利于使其产生有效变形,提高了闭锁式接电开关的工作可靠性.     

Tuning the Intermolecular Electrostatic Interaction toward High-Efficiency and Low-Cost Organic Solar Cells

Organic solar cells (OSCs) have achieved much progress with rapidly increasing power conversion efficiencies (PCEs). It should be noted that the top-performance OSCs are generally consisted of active materials with complex chemical structures, resulting in high costs. Here, combining the material design and morphology control, high-efficiency OSCs are fabricated by a low-cost donor: acceptor blend. A completely non-fused electron acceptor named Tz is designed and synthesized via introducing thiazole units on both sides of a bithiophene core, which shows an outstanding PCE of 13.3% with a typical polythiophene donor. More importantly, optimization guidelines are presented to get excellent morphology for low-cost donor:acceptor systems. Three polythiophenes are selected, poly(3-hexylthiophene) and its two derivatives with electron-withdrawing substitutions (PDCBT and PDCBT-2F), as donors to fabricate the cell devices. The computational and experimental data reveal that decreasing the electrostatic interaction between polythiophene and Tz is the key to getting a suppressed miscibility and thus a high phase purity. This study provides insight into the molecular design and donor:acceptor matching requirements for high-efficiency and low-cost OSCs.