Performance of Microstrip Couplers on an Anisotropic Substrate with an Isotropic Superstrata

The directivity of microstrip couplers on anisotropic substrates can be improved substantially by adding an isotropic superstrata layer above the microstrips. The necessary dimensions of the layer can be chosen so that fabrication is simple and noncritical.     

A Coordinate-Free Approach to Wave Reflection from a Uniaxially Anisotropic Medium

This paper presents a coordinate-free method of solving the problem of electromagnetic wave reflection from the surface of a uniaxially anisotropic medium. Based on the direct manipulation of vectors, dyadics, and their invariants, the method eliminates the use of coordinate systems. It facilitates solutions and provides results in a greater generality. The paper contains the following results in coordinate-free forms: a) the dispersion equations; b) me directions of field vectors; c) the Poynting vectors (ray vectors) and group velocities d) the' laws of reflection and refraction; and e) the transmition and reflection coefficients. The results are valid for the incident wave having any polarization, and the optic axis of the uniaxial medium being arbitrarily oriented with respect to the interface and the plane of incidence.     

A Parameterization-Based Numerical Method for Isotropic and Anisotropic Diffusion Smoothing on Non-Flat Surfaces

Neuroimaging data, such as 3-D maps of cortical thickness or neural activation, can often be analyzed more informatively with respect to the cortical surface rather than the entire volume of the brain. Any cortical surface-based analysis should be carried out using computations in the intrinsic geometry of the surface rather than using the metric of the ambient 3-D space. We present parameterization-based numerical methods for performing isotropic and anisotropic filtering on triangulated surface geometries. In contrast to existing FEM-based methods for triangulated geometries, our approach accounts for the metric of the surface. In order to discretize and numerically compute the isotropic and anisotropic geometric operators, we first parameterize the surface using a $p$-harmonic mapping. We then use this parameterization as our computational domain and account for the surface metric while carrying out isotropic and anisotropic filtering. To validate our method, we compare our numerical results to the analytical expression for isotropic diffusion on a spherical surface. We apply these methods to smoothing of mean curvature maps on the cortical surface, a step commonly required for analysis of gyrification or for registering surface-based maps across subjects.      

彩色图像特征空间变换的新算法及其应用

本文提出了一种彩色图像特征空间变换算法.该算法基于高维形象几何与仿生信息学理论,根据人眼特性,利用彩色图像中彩色信息的变化进行特征空间变换,能够提取出不受光源影响的图像特征.在彩色图像人脸检测应用中,与常见的肤色分割方法不同,该算法不需对肤色建模,不对彩色图像进行非线性彩色空间变换,而是直接将彩色原图变换到特征空间,在特征空间中定位平均脸特征数据的最佳匹配点.本文最后将该算法应用于复杂光源彩色图像的人脸检测中,实验结果验证了算法的有效性和鲁棒性,具有明显的应用价值.     

EPON技术及其在HFC网络双向改造中的应用

以广电网络双向化改造的需求为着眼点,详细阐述了EPON的工作原理、技术特点,探讨了如何结合EPON技术规划和改造HFC网络,以满足各类增值业务对HFC网络带宽和交互性的发展需求.     

Accurately Approximate Formula of Effective Filling Fraction for Microstrip Line with Isotropic Substrate and its Application to the Case with Anisotropic Substrate

The accurately approximate formula of effective filling fraction q/sub w/ is obtained for the microstrip line with zero-thickness strip and isotropic substrate. The line capacitance per unit length C/epsilon/sub 0/ for the case with anisotropic substrate can easily be obtained by using the approximate formula of q/sub w/ and C/sub 0//epsilon/sub 0/ tabulated for the wide range of shape ratio w/h. The parameters Z, v, and lambda for such a line can be calculated by using C/ epsilon/sub 0/ and C/sub 0//espsilon/sub 0/.     

从高职教育到应用型本科教育转型中几个重要问题的研究

探索从高职教育到应用型本科教育转型中人才培养目标的定位、人才培养模式的确定、课程体系开发、师资队伍建设、实验实训基地建设等转型中需重点解决的几个问题。针对这几个问题提出了解决问题的方法。     

稽核系统改造方案及其应用

稽核系统在现代组织中扮演着关键的角色,它不仅能确保财务活动的合规性,还承担着风险管理的重要职责。然而,随着业务环境的变化,传统的稽核系统也面临一些局限性和挑战。为了保持其有效性和适应性,稽核系统需要不断进行改造和优化。文中探讨了一种基于稽核系统改造方案的应用,以提高其效率和准确性,提供更有效的风险管理。     

Hilbert-Huang变换及其在心音信号分析中的应用

本文从窄带信号的角度对Hilbert-Huang变换进行探讨,证明了窄带实信号的相位等于其解析复信号的相位.据此说明在Hilbert Huang变换中,进行经验模态分解(Empirical Mode Docomposition,简称EMD)后,若EMD筛选出的模式分量为一窄带信号,则随后进行Hilbert变换得到的瞬时时频分布及能量分布从数学上讲是合理的.而且从窄带信号的角度出发,可以深刻理解Nordeng E. Huang等人定义固有模态函数(Intrinsic Mode Function,简记为IMF)的依据,以及EMD方法的实质,即从信号本身出发,将其分解为一系列中心频率可变的窄带信号.同时,从该角度出发也揭示了为实施Hilbert-Huang变换,所需进行信号分解的方向.最后,本文示例了Hibert-Huang变换在心音信号中的应用.     

三维磁各向异性目标电磁散射的MOM-CGM-FFT方法

本文给出了研究任意形状三维磁各向异性目标电磁散射问题的一种混合计算方法。该方法以磁场作为未知函数建立频域体积分 微分方程 ,使用脉冲基函数和点匹配函数的矩量法 (MOM)将之转化为线性代数方程组。在求解过程中应用共轭梯度法 (CGM)和快速傅立叶变换 (FFT)相结合的方法降低所需计算机内存和CPU时间。对均匀磁各向同性球的数值计算结果与相应Mie理论结果吻合较好。在此基础上给出了磁各向异性球和立方体的雷达散射截面。计算结果表明该计算方法兼容性强 ,是一种求解三维电磁散射问题的有效途径。     

全自动金丝球焊机的改造及应用

随着IC封装材料和技术的进步,产品引脚、焊线、焊盘尺寸正逐渐变小,芯片上焊盘间距不断减小,早期的全自动金丝球焊机已不能满足现有产品的工艺和质量要求,特提出将其改造为点胶机的设想。简要介绍了全自动金丝球焊机改造成时间/压力型全自动点胶机的系统组成和工作原理,以及其在IC封装芯片表面点胶特殊工艺中的应用,并对优缺点、影响点胶质量的因素等进行了分析,提出了改进提高的措施。     

Electrolytic Tank Solution of Electric Field Associated with Two Circular Disks on the Surface of an Isotropic Homogeneous Medium

The electric field associated with two disks on the surface of a semi-infinite isotropic homogeneous medium is found on a plane perpendicular to the disks and passing through their centers. To an accuracy which is primarily determined by the finite dimensions of the electrolytic tank, the solution is presented as families of curves. In this presentation, the magnitude of the electric field (normalized in terms of the distance of the field point from the surface, conductivity of the medium, and applied power) and the angular orientation of the field vector are plotted as functions of the ratios of the linear dimensions which characterize the geometry of the system to the distance of the field point from the surface.     

CORBA及其应用问题分析

本文从实现的角度介绍ＣＯＲＢＡ,并且分析了ＣＯＲＢＡ在应用中存在的一些问题。首先,简要介绍了ＣＯＲＢＡ 的基本概念及其轮廓。目前,在网络技术领域方面,分布式处理、异类综合和互操作性成为一个讨论和研究的热点,其中ＣＯＲＢＡ 倍受关注。文章的第二部分结合实际进一步介绍了ＣＯＲＢＡ及其实现,旨在推进ＣＯＲＢＡ 的使用和开发。最后部分提出了ＣＯＲＢＡ在应用中存在的问题并对此进行了分析     

Localized DC Field Produced by Diode Implanted in Isotropic Homogeneous Medium and Exposed to Uniform RF Field

Minimally invasive selective stimulation of biological tissue within the body can be achieved by implanting a small rectifying diode and then applying an RF field by means of electrodes or a coil on or near the surface of the body. A theoretical analysis of a simplified model consisting of a cylindrically symmetrical unit implanted in an isotropic homogeneous medium of conductivity ?and permittivity ? and exposed to a uniform RF field relates the dc component of electrode current to the detailed geometry of the electrodes of the implanted unit and to the amplitude of the applied field.     

极限编程在中小型软件企业的运用

我国软件企业中存在规模偏小、产品大多数居于产业链的低端及开发管理落后的弊端.极限编程的出现,为解决这一问题提供了新的途径.极限编程是一种＂轻量型＂软件开发方法.极限编程以沟通、简单、反馈和勇气为准则,把软件开发概括为编码、测试、倾听及设计4项基本活动.他总结了十余种核心实践活动：计划制定、系统隐喻、简单设计、结对编程、测试驱动开发、持续集成、重构、小版本发布、集体代码所有权、现场用户及编码标准等.他可以有效面对需求的频繁变化,对于规模小、进度要求高、需求变化大、质量要求严格的项目具有良好的指导意义,特别适用于我国目前为数众多的中小型软件企业.     

新型忆阻器混沌电路及其在图像加密中的应用

忆阻器是一种拥有记忆功能的电阻,目前忆阻器的研究热点及难点在于新模型的建立以及相关方面的应用。该文提出一种基于双曲正弦函数的新型磁控忆阻器模型,通过分析电压和电流的相轨迹关系,发现其具有典型的忆阻器电压-电流特性曲线。利用新建的忆阻器模型构造新型忆阻混沌系统,通过数值仿真绘出新系统的相轨迹图、分岔图、Lyapunov 指数谱等,分析了不同参数时系统的混沌演化过程。另外,基于电路仿真软件Multisim研制了实验仿真电路, 该电路结构简单、易于实际制作,且仿真实验与理论分析结论十分吻合,证实了提出的忆阻混沌系统电路在物理上是可以实现的。最后,利用新系统混沌序列对图像进行加密,重点分析了加密直方图、相邻像素相关性以及抗攻击能力与密钥敏感性,结果表明新系统对图像密钥及明文都非常敏感,密钥空间较大,新提出的忆阻混沌系统应用于图像加密具有较高的安全性能。     

磁饱和放大器及其应用

本文通过介绍磁饱和放大器的原理以及ＰＣ电源和ＭＡ电源在各种负载下的比较试验来说明一种最新磁饱和放大器及其在开关电源中的应用情况。它彻底解决了开关电源多路输出大电流、高精度的稳压问题，为工业控制计算机系统，特别是１６位系统的高精度电源开发奠定了基础。     

新型表面活性剂及其应用

从新型表面活性剂的研究热点、已工业化的新型表面活性剂的品种及应用、表面活性剂与绿色化学等方面论述了表面活性剂的发展趋势,说明了新型表面活性剂有着非常广阔的发展前景。     

新型表面活性剂及其应用

从新型表面活性剂的研究热点、已工业化的新型表面活性剂的品种及应用、表面活性剂与绿色化学等方面论述了表面活性剂的发展趋势,说明了新型表面活性剂有着非常广阔的发展前景.