高次谐波及其抑制措施

高次谐波对电能的质量具有重要的影响，严重的甚至会造成重大事故的发生。较详细地介绍了高次谐波的产生、危害和常用的抑制措施。     

High-order spectral- multimode codes

A new class of codes with high-order spectral s at zero frequency is introduced. The codes, called high-order spectral- multimode codes, are constructed through state-dependent encoding by use of the guided-scrambling coding technique, and result in efficiently coded sequences with good low-frequency characteristics.     

高阶偏振模色散及其补偿

综述了近年来国外高阶偏振模补偿的方法及其原理,并在此基础上展望了未来高阶偏振模色散补偿技术的发展趋势.     

High-order wavelet packets and cumulant field analysis

In many applications it is necessary to characterize the statistical properties of the wavelet/wavelet packet coefficients of a stationary random signal. In particular, in a stationary non-Gaussian noise scenario it may be useful to determine the high-order statistics of the wavelet packet coefficients. In this work we prove that this task may be performed through multidimensional filter banks. In particular, we show how the cumulants of the M-band wavelet packet coefficients of a strictly stationary signal are derived from those of the signal and we provide scale-recursive decomposition and reconstruction formulae to compute these cumulants. High-order wavelet packets, associated with these multidimensional filter banks, are presented along with some of their properties. It is proved that under some conditions these high-order wavelet packets allow us to define frame multiresolution analyses. Finally, the asymptotic normality of the coefficients is studied by showing the geometric decay of their polyspectra/cumulants (of order greater than two) with respect to the resolution level     

High-order harmonic generation in plasmas

The phenomenon of harmonic generation by electrons oscillating in high-intensity laser fields is surveyed and assessed as a means of producing short-wavelength radiation. Starting from the seminal early work by Sarachik and Schappert (1970), simple motivatory examples are given of incoherent harmonic generation via nonlinear scattering from single electrons. More recent studies aimed at observing the coherent version of this effect in underdense plasmas are then reviewed and some problems noted in distinguishing these harmonics from those produced via the analogous nonlinear mechanism from bound electrons in rare gases. Finally, the revival of interest in harmonics reflected from overdense plasmas is considered. Short-pulse laser-generated “surface” harmonics appear to offer a very promising, compact, and efficient means of upshifting coherent radiation to sub-10-nm wavelengths     

离轴高阶椭圆高斯光束

采用张量方法定义了离轴高阶椭圆高斯光束(DHEGB),通过矢量积分导出了DHEGB经过非轴对称光学系统的传输公式,其在零阶情况下可退化为离轴椭圆高斯光束的传输形式。数值计算和分析了DHEGB在自由空间中的传输特性,进一步研究了以离轴高阶椭圆高斯光束为基模构成的一般激光光束列阵的特性。研究结果表明,DHEGB光斑随着传输距离发生了旋转,传输特性与离轴参数有密切关系。     

NOTE ON THE JOHNSON''''S BOUNDS AND GRAHAM''''S BOUNDS FOR CONSTANT WEIGHT CODES

This paper presents four classes of codes which meet the Johnson's upper bound and twoclasses of codes which have gone beyond the Graham's lower bound.     

High-order moment computation of gray-level images

Describes an efficient approach to calculate geometric moments of a 2-D gray-level image. It is shown both theoretically and experimentally that the new method compares favorably with previous techniques, especially for high-order moments.     

高阶非线性差分变换的零知识证明身份认证协议

论文在离散对数基础上,提出了一种基于高阶非线性变系数差分变换的新的零知识证明算法。使用高阶差分状态序列,增强了系统因果强度,加强了抵抗身份欺骗和差分分析攻击的能力。把差分方法和输入输出表引入到零知识证明算法,开拓了零知识证明身份认证协议这一密码学前沿领域的研究思路。     

Capacitance bounds and equivalent radius

The isolated capacitance of conducting ellipsoids is calculated, and the resulting values are presented in the form of equivalent radii. These data are used to establish bounds for the capacitance of other conducting objects, namely, the right circular cylinder and the rectangular parallelopiped.     

一种新的高阶联想存贮模型

由于Kohonen模型对噪声极端敏感，Murakami提出一个利用带噪输入优化Kohonen模型的最小平方联想存贮模型（LSAM），大大降低了原有模型的噪声敏感性。但是与Kohonen模型一样，LSAM模型的联想存贮能力随着样本数的增加而大大下降。本文提出一种高阶联想存贮模型，对LSAM模型作了改进，使原有模型的联想存贮能力得到极大地提高。计算机模拟结果证实了这一点。     

High-order compact schemes for dispersive media

Staggered high-order compact (HOC) finite difference schemes are developed for modelling electromagnetic wave propagation in dispersive media. The main advantage of HOC schemes is their very low dispersion error, which is dominant in low-order methods. The high accuracy of HOC schemes is demonstrated by examples of wave propagation through first-order Debye and Lorentz media in one dimension.     

On error bounds and turbo-codes

Turbo-codes have been hailed as the ultimate step toward achieving the capacity limit Shannon established some 50 years ago. We look at the performance of turbo-codes with respect to various information theoretic error bounds. This comparison suggests that, if (block, or) frame error rates are considered, careful interleaver design is necessary to ensure an error performance within a fraction of a decibel of the theoretical limit for large block sizes, while random interleavers perform well for block sizes smaller than about 2 K. If the bit error performance is considered, interleaver design seems to have only a minor effect, and the codes perform close to the limit for all block sizes considered     

High-order mode coupler for millimetre wavelengths

A new type of injection filter has been developed that can be used for local-oscillator injection in millimetre-wave mixers and other narrowband diplexing applications. The insertion loss for nonresonance frequencies is typically less than 0.25 dB. For the selected resonant modes, the coupler acts as a 3 dB power divider. Insertion losses of 1.5 dB or less can be reached at these frequencies.     

高阶FIR滤波器的计算机设计与FPGA实现

根据有限冲击响应（FIR）数字滤波器的原理,综合运用Matlab和FPGA的QuartusⅡ两大计算机软件,提出了一种利用QuartusⅡ中参数化宏功能模块（LPM）的FIR滤波器设计方法。首先利用Matlab设计滤波器系数,再利用QHartusⅡ的LPM构造的乘法器和加法器,最终得到滤波结果。相比分布式算法,该法在信号处理速率要求不高,且滤波器阶数较高的情况下,可更加简单地实现滤波效果。最终在Matlab和QuartusⅡ的基础上,实现了64阶的高阶FIR数字滤波器电路的设计与仿真。     

一种自适应耦合TV和高阶PDE的图像放大模型

针对TV模型存在分块效应,而四阶PDE模型具有保持平坦区域光滑性的特点,提出自适应耦合TV和四阶PDE的正则化图像放大模型。根据图像内容合理调整耦合系数,在图像渐变和平坦区域运用四阶PDE扩散,消除分块效应;而在图像的突变区域运用TV模型滤波,保持突变边缘。实验结果表明,该算法是一种有效的图像放大方法。     

超短脉冲强激光场中氪的高次谐波研究

报道了在 10 5fs 0 .6TW激光装置上以氪气为介质产生高次谐波的实验结果。实验中主要研究了不同气压、不同激光能量、不同偏振特性对谐波辐射的影响 ,并从理论上进行了分析。结果表明 ,要想得到较强的谐波辐射信号 ,必须有适当的气体密度和激光能量 ;要想得到较高次的谐波辐射信号 ,除了有较高的激光功率密度外 ,还必须具备灵敏度高的探测器。     

高阶调制在DVB-S2中的应用

本文介绍了卫星广播系统的信道特性和振幅相移键控（APSK）调制方式．重点分析和研究了不同调制方式的信道容量、功率分布和非线性失真．通过仿真分析,指出了适合于新一代卫星数字电视广播系统的高阶调制方式。     

High-order azimuthal modes in the open resonator

Using complex-source-point method, it is shown that the linearity polarised TEM01 azimuthal modes from conventional beam wave theory should be replaced by two other sets of azimuthal modes with different polarisation configurations. The difference in frequency for the same-order mode for these two sets is calculated and verified by experiment.