基于LS-SVM-FLANN的虚拟仪器系统非线性动态补偿

针对虚拟仪器系统存在的非线性动态测量误差,提出了一种新的补偿方法.该方法依据虚拟仪器系统的静态和动态标定数据,采用最小二乘支持向量机(LS-SVM)构造的函数链接型神经网络(FLANN)辨识得到静态补偿环节及动态补偿环节模型,再将其串接到原虚拟仪器系统的后面来修正其非线性特性,改善其动态特性,从而获得系统理想的输入输出特性.实验结果表明该方法用于虚拟仪器系统动态非线性误差补偿的有效性及优越性.     

考虑测量噪声的传感器动态测量误差补偿

在传感器的输出端串接一个动态补偿环节,改善传感器的特性,补偿动态测量误差．其本质是一个带通或高通滤波器,在补偿测量误差的同时,会引入严重的高频噪声干扰,影响测量系统的精度．为了解决这个问题,研究了一个在噪声环境下,改善传感器动态特性的新方法．该方法采用试验数据,通过系统辨识的方法得到补偿环节系数,消除测量误差．同时,采用多项式预测滤波和中值滤波相结合的方法减小测量系统的噪声．最后,通过对热敏电阻动态测量误差的补偿,验证了该方法的有效性．     

石油产品检测中Pt100温度传感器动态补偿研究

以石油产品检测中闭口闪点检测为例,分析了装配式Pt100传感器和GB1水银温度计的数学模型,首次引入三阶模型描述装配式Pt100传感器的动态特性.通过阶跃响应实验,辅以Matlab软件计算仿真,得到二者传递函数,提出了基于传递函数将前者的动态特性逼近于后者的补偿算法,并将该算法应用于实际检测中,与传统的选取单一曲线进行补偿的方法相比,得到了更好的逼近效果.该算法可以推广应用到对传感器动态特性有明确要求的测温系统中.     

FIR滤波器在传感器动态补偿中的应用

本文讨论了FIR滤波器在传感器动态补偿中的应用,介绍了补偿原理。本设计的主要优点是其柔性,只要对CCD器件的时钟频率加以变化,就可以补偿多种传感器的动态性能。仿真的结果表明应用这种动态补偿的方法可以显著地提高传感器的动态特性,有效改善传感器的动态品质。     

基于数字滤波技术的虚拟频率补偿研究

为克服传感器硬件补偿方面的不足,达到对系统频带补偿目标和补偿参数的任意设置,采用向后差分法实现数字滤波,改变传统的硬件补偿方法,充分利用软件虚拟仪器的形式实现系统动态特性补偿。运行结果表明,采用虚拟仪器软件滤波技术完全可以解决频带拓宽后的频率补偿,在成本和使用灵活性上,软件滤波比硬件滤波更具有优越性。所以,采用后向差分法实现的数字滤波器是对系统进行动态补偿的一种方便易行的方法。     

龙门移动式双驱进给系统定位误差补偿方法

针对双驱进给系统结构的特性,提出了双轴定位误差建模与补偿方法.分析影响双驱进给系统定位精度的误差来源,建立基于双轴误差数据的龙门移动式双驱进给系统的速度-位置定位误差预测模型.采用开放式数控系统,提出基于交叉耦合的双驱进给系统定位误差补偿方法.在误差补偿过程中考虑双轴动态耦合特性与同步误差和单轴跟随误差耦合作用对误差补偿的影响,并进行误差补偿实验验证.实验结果表明所提出的误差补偿方法提高了龙门移动式双驱进给系统的定位精度和同步精度.     

引入扰动调节的伺服系统

以补偿原理为基础,介绍了引入扰动调节的单闭环伺服系统的设计方法,并通过仿真实验验证了在单闭环伺服系统中加入扰动调节作用后,可以改善系统的动态特性。     

圆柱度误差补偿系统控制切削试验研究

作者利用压电陶瓷逆压电效应研制成功了圆柱度误差补偿执行件。经切削试验和控制切削试验表明,静态的位移特性和动态的低阶响应特性良好,可以作为执行件用于圆柱度误差补偿系统中,也可以替代现有车床的微进给装置,另可应用到刀具磨损补偿和热变形补偿研究课题之中。     

DEB系统对单元机组动态特性的补偿

分析了DEB400协调控制系统结构和控制原理,得出DEB400系统实际是对被控对象的非线性动态特性进行了补偿,这种补偿可改善广义被控对象的动态特性,部分消除由非线性造成的对象时间常数随负荷的变化,从而提高控制质量,利用MATLAB/SIMULINK仿真其广义被控对象动态特性及系统在扰动信号下调节量和被调量的变化,证明了这一结论.     

动态电压校正装置的一种新型补偿策略

针对电压跌落而提出的一种新型补偿方法。动态电压校正装置是解决电压跌落的最有效的一个装置。基于传统补偿策略的不足,文中对补偿策略的补偿特性进行了系统的分析;讨论了在传统的最小能量补偿法基础上,提出一种新型补偿方法即对于不同跌落而采用不同的最小能量法即零有功交换和最小能量交换。通过Simulink来建立最小能量法的仿真模型,并做出仿真分析。仿真结果表明该方法在保证补偿效果的同时可以实现装置输出有功功率最小,证明方法的可行性和有效性。该方法可充分利用设备储能,有较高的经济效益。     

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     

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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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has