考虑次级电子的行波管多级降压收集极的辅助设计计算

文中较全面地讨论了多级降压收集极的物理模型.借助Orion(2.5维)软件设计出效率较高的带有再聚焦系统的四级降压收集极,并考虑了次级电子的影响,模拟计算多级降压收集极和再聚焦区的性能,为行波管整管效率的提高提供了保证.     

用于倍频程带宽、高性能行波管的小型、81～83.5％效率的2级和4级降压收集极

在美国空军(USAF)——国家航宇局(NASA)共同制定的规划中,Lewis研究中心正在进行电子对抗行波管效率的改进工作,它是通过采用多级降压收集极(MDC)以及在该中心所探索的对耗能电子注的再聚焦技术来实现的。在本规划的分析阶段,计算了整个行波管的三维电子注轨迹。轨迹计算一直到耗能电子注的再聚焦区和降压收集极。对收集极效率、收集极损耗和管子总效率进行了验证和计算。在实验工作方面,首先对不用多级降压收集极的管子性能进行估测,然后对耗能电子注的对称性、圆度和速度离散作了分析。最后,装上了多级降压收集极,使其性能最佳并进行了估测。对于理想的行波管,三维理论表明:具有对称、圆型并有最佳再聚焦电子注的2级多极降压收集极在中心频带有81％的效率(多级降压收集极),而4级多级降压收集极有85％的效率。实验结果所获得的数据表明:一个倍频程带宽——(4.8～9.6)千兆赫、功率为330～550瓦行波管的2级和4级降压收集极的最小多级降压收集极效率分别为81％和83％。     

多级降压收集极中次级电子的研究

效率与电子回流率是考核多级降压收集极的重要指标,而多级降压收集极中次级电子的存在对效率和电子回流率有重要影响.因此,对次级电子的研究有重要意义.本文探讨了次级电子发射的物理原型,并根据其编制了相应的CAD程序, 在对多级降压收集极的试算中,取得了较好的效果.     

空间行波管多级降压收集极的设计和模拟

多级降压收集极被广泛地应用于空间行波管的设计中,本文介绍了一种四级降压收集极的设计和模拟方法。通过对某一空间行波管互作用后的废电子注信息进行分析,得到电子注在收集极的入口条件,并且根据电子注入口条件确定各电极的电位,用行波管模拟软件模拟废电子注在收集极内的发射情况,计算出收集极的效率,通过分析电子注粒子运行轨迹和能量分布,优化收集极边界条件和各电极电位设置,提高收集极效率,降低电子回流率。结果表明：利用此方法计算得到的收集极效率达到80%以上,该模拟分析方法对行波管收集极的研究设计具有参考价值。     

行波管多级降压收集极CAD软件研究与实现

该文讨论了行波管多级降压收集极CAD理论模型,在二维轴对称条件下,对网格自动划分技术、二次电子发射模型、空间电荷效应计算方法、外加磁场影响、收集极效率计算方法等进行了深入研究,并在现有模型基础上进行了修改,以获得更好的模拟效果。同时在此基础上,开发了行波管多级降压收集极CAD软件UESTC_MDC,并对该软件的使用进行了简单的介绍。最后根据国外研究发展动向,对我国行波管多级降压收集极CAD软件的发展提出了一些可参考的意见和建议。     

强流电子枪电流密度和空间电荷密度计算的曲光轴传递理论与数值分析

强流电子束系统里，一般不能直接进行解析或数值分析计算其电磁场、电子轨迹和电子束的性能，而采用迭代法计算其自治的空间电荷场，在考虑电子发射的热初速时，有关的数值计算方法也非常复杂。本文利用旋转对称电子光学系统里的子午面投射轨迹理论，导出了围绕环形电子束元曲光轴的傍轴的傍轴轨迹方程，利用这一理论研究了在空间电荷和电子热初速效应同时作用下环形电子束元电子电流密度分布的演化发展，并由此建立了一套简便的计算圆形强流电子枪电流密度和空间电荷密度的数值方法。作为例子，分析计算了理想的Pierce枪的电流密度的传输规律，并证实了本方法是一种实用而有效的方法。     

多级降压收集极CAD中的二次电子发射模型

多级降压收集极被广泛应用于提高微波放大器件效率.多级降压收集极中的二次电子发射对其效率有重要影响.该文探讨了真二次电子、弹性反射电子、非弹性反射电子3种二次电子发射模型,对发射率、发射角度以及能量分布情况进行了深入分析,并对考虑二次电子后的收集极模拟计算收敛条件进行了讨论.上述结果在多级降压收集极CAD软件中得到应用,定量分析了其对多级降压收集极效率的影响.     

MAFIA在行波管多级降压收集极模拟中的应用

评述了传统二维稳态轨迹程序模拟多级降压收集极计算方法,同时提出了使用MAFIA 大信号分析软件对多级降压收集极进行全三维动态PIC模拟的方法和收集极效率简化计算公式。初步模拟实例表明该方法与实验结果吻合较好,为收集极的精确模拟和优化设计提供了新的途径。同时也指出了该方法存在的不足。     

双门聚焦结构场发射阵列阴极的计算机模拟

采用有限差分算法,对双门聚焦结构的场致发射阵列阴极进行了三维模拟计算,得到了锥尖处的电场强度,电子的运动轨迹及电位分布图.结果表明,聚焦极电位、聚焦极孔半径及聚焦极与栅极间距的变化对锥尖电场影响不大,但对电子轨迹影响很大.当聚焦极电位超过140 V时,电子束的会聚作用消失;低于-30 V时,电子束轨迹出现交叉.减小聚焦极孔径可以加强电子束的会聚作用,但当其减小至0.75 μm时,聚焦极会捕获部分边缘电子.因此在实际确立聚焦极参量时,应主要从聚焦极对电子束轨迹的会聚作用方面考虑,其次再考虑聚焦极对锥尖场强的影响.     

行波管多级降压收集极的计算和实验研究

采用多级降压收集极是提高行波管效率析有效途径之一。本文在ＳＬＡＣ－２６６程序的基础上对一支带有二级降压收集极的国外行波管进行了计算，并且将计算结果同实验结果进行了比较。同时用电子注分析仪对降压收集极区电子注和纵向速度分布进行了实验研究，获得了该二级降压收集极的部分工作曲线，并对实验结果进行了分析讨论。     

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.