有机发光器件的研究与产业化

有机发光器件(OLED)具有色彩丰富、效率高、亮度强等许多卓越优点，被誉为是新一代的平板显示器。本文回顾了OLED的研究历史，阐述了其发光机理，介绍了其基本结构，总结了其制作工艺。最后展示了近几年来OLED产业化的最新成果，并展望了其应用前景。     

实用的远程控制自动开机装置

介绍了一种实用的远程控制自动开机装置，详细叙述了其特点及电路工作原理，给出了硬件电路图，讨论了其扩展用途。     

同温层气球的现状和发展趋势

介绍了同温层气球的基本概念，讨论了其在世界各国的兴起、现状及动态，指出其关键技术和发展趋势．并对其应用前景进行了分析，说明无论在民用或军用领域都将获得广泛应用。     

多孔硅吸收光谱的研究

利用大电流剥离方法制备了多孔硅薄膜层，测定了其吸收光谱。结果发现其吸收边对应于可见光区域，同单晶硅吸收光谱相比，其吸收边发生了蓝移，并且吸收强烈。这说明多孔硅的能带结构较硅发生了改变，表现为一种新的能带结构特征。     

一种高效的适用于字词检索的数据结构

根据字词检索中字词的相关性，提出了一种可以高效的进行字词检索，并且所占用的空间大大缩小的存贮结构。此结构中，字词环环相扣，故取名为字词连环图。文章首先描述了字词连环图的数据结构，然后阐述其构造规则并对其性能进行分析论证。最后给出了其结构的Java实现。我们在PentiumⅢ600内存128M的计算机上进行测试，实验表明，将其应用到我们所设计的印刷体汉字识别系统中，每千字的平均识别时间仅增加了约1．7秒。     

J2EE架构下的电信网管系统

本首先概述了网管系统功能及其中的一个相对独立的功能子集，并将其视为一个假想系统，然后给出了传统模式下的系统结构，并指出了其缺陷，最后给出了该假想系统在J2EE架构下的实现，并讨论了其优缺点。     

应用Ansys的概率分析实现雷达结构的可靠性分析

有限元分析软件Ansys提供了概率分析功能，使其对雷达结构的概率分析非常容易。在本文中对Ansys的概率分析方法作了简单的介绍，提出了利用其概率分析功能进行结构的可靠性分析的方法，通过一个实例，说明了利用其概率分析功能实现结构的可靠性分析的可行性。     

HSUPA--引领全IP的主动力

文章从HSUPA的标准状况开始，介绍了HSUPA的关键技术，分析了其市场需求。最后预测了其商用前景。     

一种用于PWM的Rail—to—Rail比较器

本文介绍一种用于PWM的Rail-to-Rail连续型电压比较器，其输入级采用Rail-to-Rail结构，拓展了共模输入范围，输出采用电流比较器，提高了比较速度；并且从理论上分析了其组成及原理；最后通过电路仿真验证其性能，给出了仿真结果。     

WLAN的安全发展及解决方案

随着WLAN技术的不断发展，其可靠、标准化以及低成本的技术满足了人们在更灵活的工作方式以及更普遍的连接方面日益增长的需求，也在越来越多的企业中得到了应用。然而，WLAN的安全问题一直是其软肋，制约了WLAN技术的进一步发展。因为那些对安全性很“敏感”的部门，例如金融和政府部门，对于在其周边的任何人都可以任意接触到其内部网络的机密数据是不可容忍的。     

从3G无线网络看IP化回传网络需求

本文从无线网络特点的角度出发,从网络使用者最熟悉的GSM对传输网络的需求分析着手,分析了无线网络的基本特征对传输网络的需求。通过对比3G包括IP化在内的不同于GSM的新需要,提出在3G的回传网络上,哪些功能与性能是必须借鉴2G传送网的,哪些是必须在2G回传网络上提升的。基于以上分析,对于业界呼声很高的PTN产品,给出有利于现网平滑演进的PTN网络所必须具备的功能模型。     

Some practical aspects of digital transmission

There are three worlds of digital transmission?digital transmission as an area of academic research, in which theoretical limitations and complicated schemes of modulation and encoding play the starring role; digital transmission in exotic space and military applications, in which it is, or may seem to be, worthwhile to search through the noise in a huge bandwidth in order to receive a few bits per second; and the digital transmission of everyday bulk communication. This article is concerned with that third area, in which apparatus must be economical and reliable; in which the FCC limits the bandwidth we may use in radio transmission; in which the increase in attenuation with frequency limits the bandwidth it is practical to use in cable transmission; in which error rates should be low enough that error correction is an expedient that need be resorted to only in special situations.     

Fisher information with respect to cumulants

Fisher information is a measure of the best precision with which a parameter can be estimated from statistical data. It can also be defined for a continuous random variable without reference to any parameters, in which case it has a physically compelling interpretation of representing the highest precision with which the first cumulant of the random variable, i.e., its mean, can be estimated from its statistical realizations. We construct a complete hierarchy of information measures that determine the best precision with which all of the cumulants of a random variable-and thus its complete probability distribution-can be estimated from its statistical realizations. Several properties of these information measures and their generating functions are discussed.     

Approximate correctness-checking of computational results

The process of checking the correctness of time-critical computations involves a fundamental and inherently conflicting tradeoff: the precision of the checking vs the time required to perform the checking process. This tradeoff is particularly relevant when the computations are intensive and can require appreciable time for completion. This issue is addressed by an innovative technique based on an extension of the `use of certificates' which permits the precision of the correctness checking to be explicitly specified. This concept is developed relative to the broad class of problems which are amenable to the powerful and widely used B&B (branch-and-bound) strategy. It is extremely relevant to the motivation and importance of this paper to remember that `checking the correctness of results for computationally intensive problems' can be just as demanding as `generating the results themselves'. Accordingly, for time-critical applications in which a run-time result verification must be accomplished before a generated result can be released, a method for highly efficient approximate correctness checking of results in which it is efficiently determined that an obtained result is within some specified percentage of an optimal solution can be of enormous importance. This paper presents an approximate correctness checking methodology in which the precision of the result check can be explicitly specified and guaranteed even when an exact correct result is unknown, This controllable tradeoff, inherent in this method, can be the basis for new classes of adaptive result-checking strategies in which the precision of the check of a result can be varied, depending on the impact of the result within time-critical applications     

A strategy for designing error detection schemes for general datanetworks

The author presents a five-step methodology that provides insight into the order in which errors should be considered when designing an error detection scheme, which types of error detection mechanisms are most effective, and which layer should be responsible for detecting a given type of error     

Analysis of an amplitude-locked loop

The amplitude-locked loop (ALL) is a closed-loop servosystem which is the dual of the phaselocked loop (PLL). An analysis is obtained which shows that the circuit has an output which is the reciprocal of the modulus of any carrier-based input and can be made to be phase-sensitive     

利用改进频域补偿和分数阶Fourier变换的多帧相参TBD方法

天基雷达接收空间高速机动目标的多帧回波数据,本文提出一种利用改进频域补偿和分数阶Fourier变换的多帧相参TBD方法用于目标参数估计。该方法利用改进的频域补偿方法将各数据帧中出现距离徙动的目标回波信号校正到一个距离单元中,然后在补偿由于不同数据帧带来的固有相位差基础上对一个距离单元内数据做分数阶Fourier变换而用于目标参数估计。该方法充分利用多帧回波数据间的相位信息,避免了常规检测前跟踪方法由于帧间非相参积累所导致的能量积累损失问题,在低信噪比的情况下能够获得较高的参数估计性能。仿真结果证明了所提方法的有效性。      

Equivalent circuit of an evanescent-mode inductive element

By the use of a partial-fraction expansion of the propagation constant in terms of the angular frequency, a successive series of equivalent-circuit approximations is obtained for the parallel element in the II representation of a length of evanescent-mode waveguide. The first of these approximations simply adds a parallel capacitance to the low-frequency inductance, an element which can be readily absorbed into any tuning capacitor which may be required. The third-order approximation can be put in various forms, some of which similarly exhibit a parallel capacitive element.     

Far-field sector scanning using a sampled multielement ultrasonic receiving array

A. technique which enables target bearing and range information to be obtained by sequential sampling of a multielement linear ultrasonic array is described. A resultant output frequency is extracted which is shown to be a function of the target angle, and results are given which confirm theoretical expectations.     

Making the best use of the airways: an important requirement formilitary communications

The growing communication demands of modern warfare must be met with the fixed resources of the electromagnetic spectrum. When an armed force is deployed, frequencies must be assigned, within a restricted bandwidth and in a short time-scale, to its many (e.g. 400) radios so as to minimise the interference between them. There are too many ways in which a frequency allocation can be made for them all to be evaluated; instead the best assignment that can be discovered within a limited time must be chosen. This is typical of a class of problems known as combinatorial optimisation problems. This paper discusses some of the methods which can be used for solving such problems and presents results for a hybrid algorithm based on construction methods, tabu search and genetic algorithms which has been developed at DERA-Malvern