爆破式ARM 对典型雷达目标的毁伤效果研究

为分析爆破式反辐射导弹（anti-radiationmissile,ARM）对典型相控阵雷达目标的毁伤效果,对ARM爆破战斗部的引战配合进行研究。在分析空地反辐射导弹末段弹道特性及爆破式战斗部毁伤机理的基础上,建立了爆破式ARM对典型目标触发起爆和近炸起爆时的毁伤模型,并采用Monte-Carlo仿真方法确定了近炸起爆的最佳起爆高度及不同起爆方式的导弹单发毁伤概率。仿真结果表明：对于天线高度较高的目标适宜采用近炸起爆,对于天线高度较低的目标适宜采用触发起爆。     

航天器贮箱液体的有效转动惯量(上)

分析整理了航天器圆环筒形平底贮箱内液体的有效转动惯量计算方法,修正了现有文献中的错误,在常用的参数范围内对液体的有效转动惯量进行了计算,对其变化规律和影响因素做了物理分析,推导了液体滚转有效转动惯量的计算公式,并给出了适用的近似计算方法.对于纵向挡板引起的液体滚转有效转动惯量,给出了工程计算方法,能够确定滚转时液体的有...     

浅析广电新运维体系的建设

本文通过分析广电运维体系现状,结合互动电视等三网融合新业务发展需求的提出,浅析了广电新运维体系建设的总体思路与建设重点,并希望以此为广电的三网融合竞争之路提供更有力的支持.     

Chirality‐Based Biosensors

The fabrication of chiral nanostructures gives rise to characteristic chiroptical activity, which can be used for chirality‐based biosensors. Great progress is made in the use of nanoassemblies for the construction of chiral nanoparticle dimers, pyramids, helices, and twisted structures, and their chiroptical activities correlate with diverse structural geometries and enantiomeric configurations. In DNA‐hybridization‐based chiral nanoassemblies, the assembly parameters, such as the components, gaps, multicomponents, and the aftergrowth of metal, can result in multiple bands and enhanced chiroptical effects. Based on known chiral nanostructures, the existing chiral nanoassembly‐based biosensors together with their targets and signal amplification strategies are reviewed. Chirality involves multiple signals, and multitarget biosensors are introduced with newly developed chiral architectures for the accurate and reliable monitoring of biomarkers in living cells. The interactions between chiral nanoarchitectures and biosystems are also highlighted, which are important not only in the chiral dynamic switching of nano‐objects for biomonitoring, but also in manipulating cell growth, proliferation, and adhesion. The future perspectives on chiral fabrication and its use in biosensors are also comprehensively discussed.     

Magnetic Field‐Enhanced Thermoelectric Performance in Dirac Semimetal Cd3As2 Crystals with Different Carrier Concentrations

The magneto‐thermoelectric figure of merit (ZT) in crystals of the topological Dirac semimetal Cd₃As₂ with different carrier concentrations is studied. The ZTs for all the crystals increase with the temperature and show maxima at high temperatures. Meanwhile, the temperatures corresponding to the ZT maxima increase with the carrier concentration. The limit to the improvement in ZT(T) at high temperature could be related to the unusual large enhancement in thermal conductivity at elevated temperatures. The bipolar effect and Dirac liquid behavior are presented as processes possibly responsible for the peculiar behavior of the thermal conductivity. Applying a transverse magnetic field initially leads to a dramatic enhancement and, subsequently, to a slight reduction in ZT for all the crystals. The maximum ZT achieved in a magnetic field increases with the carrier concentration and reaches 1.24 at 450 K in a magnetic field of 9 T for the crystal with the highest carrier concentration. It is expected that this work will be beneficial to the current interests in optimizing the thermoelectric properties of quantum topological materials.     

相干光通信中的光学桥接器

相干光通信技术是提高接收机灵敏度,发展大容量高码率激光通信系统的重要技术手段,光学桥接器将信号激光和本振激光链接到光电探测器进行相干探测处理,是相干光通信系统的关键器件之一.对近20多年来发展的光学桥接器进行了总结和分类,介绍了不同光学桥接器的原理、构造和性能,分析了光学桥接器的关键技术.     

一种带新型直流失调补偿电路的模拟数字控制可配置的自动增益控制器

本文提出一种可用于零中频接收机的模拟/数字控制可配置的自动增益控制环路的设计,应用一种新型的直流失调消除电路。这种自动增益控制环路可配置于模拟或者数字控制,以便与不同的基带芯片兼容。本文更进一步提出了一种新型的直流失调消除电路,这种直流失调消除电路实现了低于10KHz的下限截止频率（HPCF,high pass cutoff frequency）。自动增益控制环路电路采用0.18um CMOS工艺。当配置于模拟控制模式下,这种自动增益控制环路的增益动态范围为70dB,3dB带宽大于60M。当配置于数字控制模式下,通过5比特的数字控制码控制,这种自动增益控制环路的增益动态范围为64dB,步进精度2dB,步进误差小于0.3dB。当输入引入40mV直流失调,电路输出直流失调电压小于1.5mV。电路整体功耗小于3.5mA,面积800um*300um。     

水面舰艇的光电隐身技术及对策

要提高水面舰艇在未来海战中的生存能力,就要降低目标被探测、发现和摧毁的概率．西方国家研制的隐形战舰,采用了各种光电隐形技术．本文论述了水面舰艇光电隐身技术,并提出对策．     

Design optimization of stacked layer dielectrics for minimum gate leakage currents

An effective model to evaluate the leakage currents for different stacked gates deep submicron MOS transistors is presented. For a given equivalent oxide thickness of a stacked gate, the gate leakage current decreases with an increase of high-k dielectric thickness or a decrease of interlayer thickness. Turning points at high gate biases of the I–V curves are observed for Si₃N₄/SiO₂, Ta₂O₅/SiO₂, Ta₂O₅/SiO_2−yN_y, Ta₂O₅/Si₃N₄, and TiO₂/SiO₂ stacked gates except for Al₂O₃/SiO₂ structure. Design optimization for the stacked gate architecture to obtain the minimum gate leakage current is evaluated.     

多位LED串行显示电路设计与应用

74HC595A芯片具有串行输入、并行输出功能,利用该集成电路可设计多位LED(发光二极管)串行显示电路。文中介绍了利用该芯片设计的12位LED串行显示电路,详细说明了该电路的工作原理及编程思路,并给出了参考程序。该电路只占用单片机3根口线,较并行显示方式极大地节省了系统资源,已在实际系统中得到应用。