一种分析无线电测向准确度的方法

结合对无线电测向误差的分析,介绍了曲线拟合的基本概念和简单算法,及其在国家无线电监测中心上海监测站进行测向误差与频率对应关系研究时实际应用的结果。实验结果表明,曲线拟合是消除随机测向误差、寻找测向误差规律的有效方法。     

短波固定站测向误差分析方法

本文阐述了测向误差产生的因素,采用曲线拟合方法,对福建监测站多年以来跟踪测试到的测向误差进行对比分析.     

俯仰角对一维干涉仪测向精度的影响

阐述了存在俯仰角时一维干涉仪的测向原理,论述了俯仰角对测向误差的影响,计算了同时存在相位误差和俯仰角条件下的测向误差,介绍了几种减小测向误差的方法,利用Matlab软件仿真分析了测向误差,给出了一种误差校正系统。     

测向精度试验中测向距离的选择方法

分析测向距离选择应考虑的因素,从测向的原理及测向误差引起的机理入手,通过对测向天线阵接收信号来波的非平面性所引起的测向误差理论分析和计算,给出了典型条件下的测向距离和测向误差的图表和关系曲线。以此为基础,提出了测向距离选择的原则与方法。为测向精度试验中测向距离的选择提供了科学的依据。     

最小二乘曲线拟合在SKE测向中的应用

本文介绍了最小二乘曲线拟合方法,阐述了位置保持设备(以下简称SKE)及其测向原理。根据SKE定向天线信号的特点,给出了利用最小二乘曲线拟合实现SKE测向的方法。     

测向精度试验中测向距离的选择方法

分析测向距离选择应考虑的因素,从测向的原理及测向误差引起的机理入手,通过对测向天线阵接收信号来波的非平面性所引起的测向误差理论分析和计算,给出了典条件下的测向距离和测向误差的图表和关系曲线。以此为基础,提出了测向距离选择的原则与方法,为测向精度试验中测向距离的选择提供了科学的依据。     

近距离通信测向场地大小与测向误差关系分析

根据大基础天线通信测向设备对近距离测向场地的要求,以长基线干涉仪测向系统的原理为基础,讨论了近距离时测向场地大小引起测向误差的原因,分析得出了标准测向场地大小引起测向误差的计算公式,并进行了举例分析,旨在为通信测向设备的性能测定提供理论依据。     

多径效应引起的测向误差分析

针对某设备在测向试验中出现的正弦型测向误差分布的现象，文章对存在多径场入射情况时旋转测向体制中交叉波束测向误差进行了分析，得到了其误差表达式，证明正弦型测向误差分布是一种典型的多径效应结果，最后讨论了减少正弦型测向误差分布的方法。     

无线电通信测向中的极化误差分析

无线电通信测向中,因极化效应而产生测向误差不容忽视。通过论述测向中极化误差的各种相关因素,分析非正常极化波所引起的测向误差及地面反射波与直射波的相位滞后等问题,分析无线电测向中的极化误差产生基理,并结合实际应用提出减小极化误差的措施,提出采取取平均值法和相应的测向体制以解决在无线电测向中减小极化误差的方法。     

结构变形对测向天线精度的影响

主要研究了结构变形对测向精度的影响。通过测向天线采用五阵元体制算出了间距误差对相位的影响,分析了测向天线的测向算法。通过自重和风负荷的受力计算,给出了天线变形计算。通过计算有间距误差和无误差时的相位,得出了在受力变形时与理论相位差之间的误差。对于天线受力变形所引起的测向误差也给出了结果。为今后对测向天线进行机电综合分析提供了一种方法。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

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.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.