热释电非制冷红外焦平面现状及发展趋势

一维和二维阵列的热释电非制冷红外焦平面非常适合应用于热成像.混合式的BST铁电探测器降低了成本,市场潜力巨大.分析了热释电非制冷红外焦平面阵列探测技术的优势,介绍了热释电非制冷红外探测器工作原理及热释电非制冷红外焦平面阵列对探测材料的要求,指出了混合式及单片式热释电非制冷红外焦平面阵列发展趋势.制备高一致性和高性能的大阵列的探测元是发展非制冷红外焦平面的关键,针对我国在热释电非制冷红外焦平面阵列研究方面存在的问题,提出了下一步研究的方向及重点.     

非制冷红外焦平面阵列

红外技术的一项重要进展是非制冷焦平面阵列，在红外探测和热成像的军、民应用中，大型非制冷焦平面阵列与制冷的光子探测器阵列相比有很多优点。文章评述利用热探测机理的非制冷焦平面阵列的最近发展。其主要技术途径有电阻测射热计和铁电薄膜单片非制冷焦平面阵列和铁电混合式非制冷焦平面阵列。     

非制冷红外焦平面阵列的定标试验研究

为将非制冷红外焦平面阵列(UFPA)应用于地基云红外被动遥感系统,就非制冷红外焦平面阵列的响应特性进行了试验研究.在定标模型理论分析的基础上,提出了一种考虑探测器工作温度效应的适合于非制冷红外焦平面阵列的辐射定标模型,设计了基于标准辐射源的定标方法.试验结果表明,非制冷红外焦平面阵列响应动态范围大、线性度好,探测器工作温度效应可作线性化处理,辐射定标模型反演标准偏差为0.72 w.m-2.sr-1.     

非制冷红外焦平面阵列信号处理系统设计

介绍了320×240非制冷红外焦平面阵列(UFPA)的信号处理系统;采用复杂可编程逻辑器件(FPGA)产生红外焦平面阵列的驱动时序,应用数字信号处理(DSP)技术实现红外焦平面阵列的非均匀校正.实验及仿真结果表明:FPGA可产生焦平面阵列所需时序,DSP对焦平面阵列的非均匀校正效果较好.     

非制冷红外焦平面阵列信号处理系统设计

介绍了320-240非制冷红外焦平面阵列（UFPA）的信号处理系统;采用复杂可编程逻辑器件（FPGA）产生红外焦平面阵列的驱动时序,应用数字信号处理（DSP）技术实现红外焦平面阵列的非均匀校正。实验及仿真结果表明：FPGA可产生焦平面阵列所需时序。DSP对焦平面阵列的非均匀校正效果较好。     

国外非制冷红外焦平面阵列探测器进展

非制冷红外焦平面阵列探测器是目前发展最为迅速的红外探测器种类之一,并已广泛渗透到军事和民事应用中.本文重点阐述几种国外具有代表性的非制冷红外焦平面探测器的现状及其发展趋势.     

非制冷红外焦平面技术述评（上）

近年来,红外非制冷焦平面阵列技术已取得令人瞩目的进展,凭借其低成本,可接受的性能,正在开拓民用乃至军用市场。本文描述了目前主要的两种非制冷焦平面阵列技术的发展状况,并对二者以及它们与制冷型焦平面阵列进行比较与探讨。     

非制冷热成像最新发展和应用前景

综述了非制冷热成像技术的最新发展和研究趋势及其应用前景。热释电焦平面阵列和微测热辐射计焦平面阵列已成为两种主流非制冷红外探测器。前者的年增长率为11．4％,后者的年增长率为32．4％。非制冷热成像技术在作用距离上优于微光成像、在体积和成本上优于制冷红外成像技术,使之成为中距离探测的主力军,并有可能在不远的将来在许多应用方面代替制冷热成像技术。     

非制冷MEMS红外成像系统

利用光力学效应设计研制了非制冷MEMS红外焦平面阵列及图像探测系统,提出并制作了新型间隔镀金的、无Si衬底的非制冷MEMS红外成像焦平面阵列,分析了FPA热响应时间、NETD、像元的一致性等问题,与光学检测系统共同组成红外成像系统,成功得到了室温背景下人体的热像.     

环境温度补偿的红外焦平面阵列非均匀性校正

由于非制冷红外焦平面阵列的非均匀性随使用环境温度的变化漂移,校正参数需要经常更新.针对非制冷红外焦平面阵列非均匀这一特点和定标校正的不足,应用红外焦平面阵列二元非线性的非均匀性理论模型,提出了环境温度补偿的非均匀性校正,该方法既考虑了在大动态范围目标温度探测器响应的非线性,又考虑了使用环境温度变化对非均匀性的影响,从而...     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

位屏蔽多叉树搜索射频识别防碰撞算法

针对RFID树型防碰撞算法中时隙数多、数据通行量大等问题,提出了一种改进的多叉树防碰撞算法,阅读器准确检测碰撞位并向标签反馈碰撞位信息,标签对阅读器已知的ID位进行屏蔽,把ID号转换成连续碰撞的序列号.阅读器利用屏蔽位信息和标签返回的碰撞位编码信息,对标签进行分层分类搜索.通过对标签ID进行屏蔽,阅读器和标签间仅发送对方不知道的碰撞位信息.该算法减少了碰撞时隙和识别时隙,避免了空闲时隙,减少了阅读器和标签间的数据通信量.理论分析和仿真结果表明,该算法减少了系统的时隙总数和数据通信量,提高了阅读器的识别效率.     

Alternative Schemes for Dynamic Secure VPN Deployment in UMTS

Three alternative schemes for secure Virtual Private Network (VPN) deployment over the Universal Mobile Telecommunication System (UMTS) are proposed and analyzed. The proposed schemes enable a mobile node to voluntarily establish an IPsec-based secure channel to a private network. The alternative schemes differ in the location where the IPsec functionality is placed within the UMTS network architecture (mobile node, access network, and UMTS network border), depending on the employed security model, and whether data in transit are ever in clear-text, or available to be tapped by outsiders. The provided levels of privacy in the deployed VPN schemes, as well as the employed authentication models are examined. An analysis in terms of cost, complexity, and performance overhead that each method imposes to the underlying network architecture, as well as to the mobile devices is presented. The level of system reliability and scalability in granting security services is presented. The VPN management, usability, and trusted relations, as well as their behavior when a mobile user moves are analyzed. The use of special applications that require access to encapsulated data traffic is explored. Finally, an overall comparison of the proposed schemes from the security and operation point of view summarizes their relative performance. Christos Xenakis received his B.Sc. degree in computer science in 1993 and his M.Sc. degree in telecommunication and computer networks in 1996, both from the Department of Informatics and Telecommunications, University of Athens, Greece. In 2004 he received his Ph.D. from the University of Athens (Department of Informatics and Telecommunications). From 1998–2000 was with the Greek telecoms system development firm Teletel S.A., where was involved in the design and development of advanced telecommunications subsystems for ISDN, ATM, GSM, and GPRS. Since 1996 he has been a member of the Communication Networks Laboratory of the University of Athens. He has participated in numerous projects realized in the context of EU Programs (ACTS, ESPRIT, IST). His research interests are in the field of mobile/wireless networks, security and distributed network management. He is the author of over 15 papers in the above areas. Lazaros Merakos received the Diploma in electrical and mechanical engineering from the National Technical University of Athens, Greece, in 1978, and the M.S. and Ph.D. degrees in electrical engineering from the State University of New York, Buffalo, in 1981 and 1984, respectively. From 1983 to 1986, he was on the faculty of Electrical Engineering and Computer Science at the University of Connecticut, Storrs. From 1986 to 1994 he was on the faculty of the Electrical and Computer Engineering Department at Northeastern University, Boston, MA. During the period 1993–1994 he served as Director of the Communications and Digital Processing Research Center at Northeastern University. During the summers of 1990 and 1991, he was a Visiting Scientist at the IBM T. J. Watson Research Center, Yorktown Heights, NY. In 1994, he joined the faculty of the University of Athens, Athens, Greece, where he is presently a Professor in the Department of Informatics and Telecommunications, and Director of the Communication Networks Laboratory (UoA-CNL) and the Networks Operations and Management Center. His research interests are in the design and performance analysis of broadband networks, and wireless/mobile communication systems and services. He has authored more than 150 papers in the above areas. Since 1995, he is leading the research activities of UoA-CNL in the area of mobile communications, in the framework of the Advanced Communication Technologies & Services (ACTS) and Information Society Technologies (IST) programmes funded by the European Union (projects RAINBOW, Magic WAND, WINE, MOBIVAS, POLOS, ANWIRE). He is chairman of the board of the Greek Universities Network, the Greek Schools Network, and member of the board of the Greek Research Network. In 1994, he received the Guanella Award for the Best Paper presented at the International Zurich Seminar on Mobile Communications.     

LTPS工艺中光刻胶与膜层粘附力的研究

本文对影响LTPS工艺中光刻胶和衬底间粘附力的4个因素进行了实验及理论分析。经实验发现:衬底的材质和粗糙度以及光刻胶中分子量的分布是影响光刻胶和衬底粘附力的最重要的两个因素。在改善粘附力方面HMDS对于电负性较强的金属衬底和光刻胶的粘附力有较好的改善效果,对于SiNX、A-Si及P-Si衬底改善效果明显,且无差异,对于ITO没有改善。光刻胶涂布后适当延长烘烤时间也可以有效改善光刻胶和衬底的粘附力。     

合成孔径雷达Mosaic模式系统性能分析

主要讨论SAR的马赛克（Mosaic）模式的系统特性。首先简述Mosaic模式的特点及与扫描（Scan）和滑动聚束模式间的差异,然后详细分析了Mosaic模式下方位扫描关系及其旋转角,推导了多普勒频率的表达式和方位分辨率的计算公式,仿真分析计算了不同方位位置目标的多普勒历程和相应的方位分辨率,为系统设计提供了技术基础。     

GaN基板上超薄阳极氧化铝的制备

在草酸溶液中对GaN基板上超薄Al膜进行阳极氧化,结合扫描电镜对阳极氧化铝形貌进行表征,系统研究了超薄Al膜的腐蚀条件和氧化过程,以及Al膜的厚度,反应变化时间和实验难度系数之间的关系。多孔状阳极氧化铝的孔径、分布及有序度等对氧化电压、氧化时间、电解液温度和溶液浓度等参数较为敏感。通过深层次的机理分析,给出了相应的合理解释。在此基础上,优化了超薄阳极氧化铝的制备参数,提升了实验的稳定性及重复性,促进了阳极氧化铝在GaN材料和器件中的应用。     

Progress in doping semiconductor nanowires during growth

The anisotropic growth of one-dimensional or filamental crystals in the form of microwires and nanowires constitutes a rich domain of epitaxy and newly enabled applications at different length and size scales. Significant progress has been accomplished in controlling the growth, morphology, and properties of semiconductor nanowires and consequently their device level performance. The objective of this review is two-fold: to highlight progress up to date in nanowire doping and to discuss the remaining fundamental challenges. We focus on the most common semiconductor nanowire growth mechanism, the vapor-liquid-solid growth, and the perturbation of its kinetic and thermodynamic aspects with the introduction of dopants. We survey the origins of dopant gradients in nanowire growth and summarize quantification techniques for dopants and free-carrier concentrations. We analyze the morphological changes due to dopants and the influence of growth droplet seeds on composition and morphology and review growth aspects and alternatives that can mitigate these effects. We then summarize some of the remaining issues pertaining to dopant control in nanowires.     

网络空间威胁狩猎的研究综述

近年来,随着网络的普及和信息化水平的不断提高,越来越多的公司把重要信息和机密文件存储在连接着网络的计算机上。但是,由于网络攻击的手段层出不穷,威胁狩猎的思想和理念孕育而生并且逐渐成熟。由此,首先对网络空间威胁的定义和攻击流程模型进行介绍,再阐述了威胁狩猎的定义和核心技术,然后描述了威胁狩猎使用的工具;最后,概括总结现有的主流威胁狩猎的框架,比较各个框架的优缺点,并阐明了下一步的发展方向。     

UAT数据链上行报文时隙实时动态分配算法研究

基于UAT数据链上行TIS-B报文和FIS-B报文时如何合理的利用时间资源,制定地面上行数据的时隙策略,避免出现报文重叠和交织的问题,提出了时隙实时动态分配的算法。重点讨论了算法中时间段划分、配置报文发射窗口、窗口轮循变换和配置报文窗口偏移,对算法进行了结果的计算和实际工程中的应用分析,表明该方法完全满足实际工程中的应用要求,并提高了系统的实时性和动态性。     

一种基于附加电池的锂电池组主动均衡方法

电动汽车使用的串联锂电池组在多次循环充放电后会出现不均衡的现象,导致电池组容量和寿命的减少。为解决这一问题,文中提出了一种基于附加电池的非能耗式充放电主动均衡方法并对均衡电路及均衡控制策略进行设计。该均衡方案在充电时将电压高的单体能量转移给附加电池,在放电时将附加电池的能量转移给电压低的单体电池,实现了能量的自由存储与转移。文中对均衡电路的原理和均衡控制策略进行了分析,并应用MATLAB/Simulink中的Simcape与Stateflow分别对均衡电路及控制策略进行建模与仿真分析。仿真结果表明,该均衡控制方法能快速实现电池组的均衡,且均衡后的电池组可用容量有明显提高。