小波域中值滤波器在陀螺寻北仪中的应用

研究了利用小波变换消除陀螺干扰漂移的方法．通过对陀螺寻北仪两位置寻北方案的分析，表明陀螺随机干扰信号是影响系统精度的主要误差源．为此将中值滤波与小波阈值去噪相结合构造了小波域中值滤波器，并应用于陀螺数据处理中．寻北试验结果表明，该滤波器在有效对白噪声滤波的同时也能较好地去除脉冲噪声，与传统的去噪方法相比，寻北精度提高20％，对陀螺各种干扰信号具有很好的抑制作用．     

无源和有源滤波器串联构成的并联型综合电力滤波系统

设计了一种新的综合电力滤波系统,它由无源滤波器和小容量有源滤波器串联构成,与被补偿的谐波负载并联连接,控制有源滤波器输出,使滤波器串联支路对各次谐波的阻抗都为零,大大提高了无源滤波器的滤波效果.介绍了综合电力滤波系统的主电路和控制电路,分析了滤波原理及控制方法.建立了一套实验系统,对整流负载产生的谐波用综合滤波装置进行消除谐波实验.通过对有源滤波器投入前后电网电流波形的比较,可以证明,所提出的综合电力滤波系统的滤波原理及控制方法是正确的,对负载产生的各次谐波具有良好的滤波效果.     

基于多模介质谐振器的高集成单体双路滤波电路

针对传统设计中,基站系统存在多个高Q值 、高功率容限的介质滤波器而导致体积大 、重量大和成本高等问题,提出了单体双路滤波电路设计方法,将2个滤波器或滤波电路集成为单个具有2个输入端口和2个输出端口的电路。通过充分利用多模介质谐振器的电磁场特性,仅使用一个金属腔和介质谐振器就实现2个具有相同性能的滤波通道。尽管集成后的2个信号通道共用一个谐振器,通道间也能实现大于20 dB的高隔离效果。介绍了包括单体双路滤波器及其与双输入双输出Doherty功率放大器的协同融合 、单体双路平衡式滤波器和单体双路巴伦滤波器等电路的设计方法。提出的单体双路滤波电路可以替代传统设计方法中的2个独立滤波电路,从而减少无线系统中滤波电路的数量,实现高集成和小型化。     

FIR滤波器在光纤陀螺中的应用

光纤陀螺的研究主要分为光路和电路2个部分,电路部分中数字信号处理的算法影响整个光纤陀螺系统的精度．介绍了平滑滤波器和基于分布式算法的FIR滤波器的基本原理;采用Matlab工具箱中的fdatool设计了滤波器系数,并进行了仿真,仿真结果表明设计可靠、合理且满足设计要求;最后使用VerilogHDL语言实现了滤波器硬件电路．     

基于大型轧钢厂混合型电力滤波器的设计

运用一种混合型电力滤波系统来实现电网中日趋严重的谐波污染的治理,混合型电力滤波器采用了有源滤波器通过滤波电感直接和无源滤波器串联.有效的降低了成本和减少安装空间.此接线方式具有装置的体积小、投资少、安装维护方便等特点.提高了装置工作的经济性.     

通用电流模式滤波器的系统设计

电流模式滤波电路因具有频带宽,功耗小,动态范围大等优点已逐渐应用在高频、高速信号处理电路中,当前电流模式滤波电路中对通用高阶电流模式滤波器的设计研究存在明显不足,通过对电流模式滤波器的通用传输函数进行系统分析,提出了基于MOCCII设计任意阶电流模式滤波器的电路,该电路结构简单,元件参数容易确定,所有的RC元件均接地,便于单片集成。改变输出电流的组合方式,可实现多种功能的滤波器。结合实例进行了电路设计及PSPICE仿真,仿真结果证实了该设计的可行性。     

基于multisim和filter solution的巴特沃斯滤波器的设计与仿真

巴特沃斯滤波器因为具有最平坦的通带幅频特性,故广泛被电子设计者所应用,但其低阶的滤波器通带边界下降较慢。高阶滤波电路通常都是以1阶和2阶滤波器的设计为基础,为此,本文从基础的2阶巴特沃斯低通滤波器的设计入手,详细介绍设计过程,然后在multisim下给予验证,最后用filter solution设计高阶的,通带边界下降更快的低通滤波器。     

基于第3代电流传送器的电流模式有源滤波器的设计

 设计了一种有源滤波网络,提出了一种基于第3代电流传送器(Third-Generation Current Conveyor,CCⅢ)的电流模式二阶滤波器的系统设计方法,导出了该系统的设计公式,其电路由1个CCⅢ+和4个无源元件构成,可实现二阶低通、高通、带通滤波功能.各滤波电路具有很低的无源灵敏度和有源灵敏度,端口网络电路简单,电路结构固定,通过级联易生成高阶滤波电路.用PSPICE对电路进行了仿真,仿真结果表明,设计理论正确,设计方法可行.     

多频带通滤波器技术(英文)

结合笔者及其课题组多年来的研究成果,集中介绍了近几年出现的多频带通滤波器的设计和实现技术———为得到各通带频率和带宽都可控的多频滤波器,利用多通带谐振器设计双频及三频滤波器;为减小滤波器尺寸,利用阶跃阻抗谐振器设计双频及三频滤波器;为方便控制通带频率,基于枝节线加载谐振器设计双频及三频滤波器;为获得更好的带外特性和更多通带,基于组合谐振器设计三频及四频滤波器.文中最后介绍了基于多枝节加载谐振器的高阶双频滤波器的设计方法.在保持第一通带特性不变的前提下,该高阶双频滤波器的第二通带可以很方便地进行调节.     

高功率激光系统空间滤波器的重要参数

提出空间滤波器的透镜焦距需同时满足真空度和透镜球差最小的要求,滤波小孔的发散角必须小于某一定值才能有效滤除高频分量,并由此计算出本文所用高功率激光系统中的空间滤波器的小孔孔径约为20倍衍射极限.同时,分析了滤波小孔在光轴上所处位置的范围,即得出只要处于距焦平面1.04mm的范围内都是合理的结论.利用光学设计软件Fred建立模型进行验证,模拟结果表明,根据本文提出的计算方法所设计的空间滤波器能够有效地滤除系统中的高频分量和杂散光.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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