感应电机的非线性干扰抑制控制

提出一个基于相似反对称结构设计的L2增益干扰抑制控制器.针对感应电机负载转矩的不确定性,在设计控制器时引入与不确定性参数相应的可调参数.以相似反对称结构为闭环期望结构,采用逆推法设计电机转速和转子磁链跟踪控制器.并通过L2增益算法进行耗散性分析,使系统不仅对不确定项具有鲁棒性,而且对外部干扰具有抑制作用,保证闭环系统的动静态品质.仿真结果表明了所提出控制器的有效性.     

行(列)反对称矩阵的极分解及其扰动界

考虑行(列)反对称矩阵的极分解、广义逆和扰动界,给出了行(列)反对称矩阵的极分解和广义逆的计算公式,并给出了行(列)反对称矩阵极分解的系列扰动界.结果表明,所给方法既减少了计算量与存储量,又不会降低数值精度.     

行（列）反对称矩阵的极分解及其广义逆

考虑行（列）反对称矩阵的极分解和广义逆, 给出了行（列）反对称矩阵的极分解和广义逆计算公式, 并对行（列）反对称矩阵的极分解作了扰动分析.
结果表明, 所给方法既减少了计算量与存储量, 又保证了数值精度.     

基于动态相量的母线电压短时大扰动分析与源定位研究

短时电压扰动源定位对协调供用电双方纠纷、缓减扰动及排除事故具有关键性作用.在分析回顾已有扰动源定位方法的基础上,首先提出适合非平稳扰动信号分析的一种动态相量量测方法,完成母线电压短时大扰动分析检测,然后基于动态相量分析源定位的等效模型及其参数计算,最后通过上游系统参数、下游负荷电流变化与电压变化量的关系分析,定量给出母线电压短时扰动源定位结果.算例证明,该法能在复杂配电网中正确完成短时电压扰动源的定位,可应用于电能质量监测系统.     

基于基因转录的机加工车间主动调度研究

在个性化制造企业生产过程中,存在着各式各样的扰动,包括机械设备故障、紧急插单、原料供应不足等.在扰动环境中,如何维持调度系统的稳健是制造系统研究的难点和热点.鉴于扰动事件成因分析与生物信息学具有相似性,提出了基因转录的研究方法.首先针对生产过程中的扰动事件进行了分类与成因分析;接下来,根据扰动因子之间的关系,借助基因生物学中的动力学模型,研究扰动因子之间的关系,通过希尔函数计算扰动因子之间的耦合值;然后对耦合值进行判断,根据判断结果,在不需要产生新的调度方案前,采取主动调度的方法消除扰动,确保生产调度系统恢复稳态;最后通过经典的调度问题验证了方法的可行性.     

计及暂态电压稳定性的自适应低频减载方案

根据电力系统的频率响应信息,提出一种发生扰动后系统实时不平衡功率的计算方法,补偿电压偏移造成的有功缺额影响. 同时,考虑负荷节点的暂态电压稳定性,制定基于频率响应的自适应低频减载方案. 通过在IEEE-39节点系统进行算例仿真,验证系统功率缺额计算的准确性以及自适应低频减载方案的有效性. 结果表明,该方案可改善低频减载控制中的频率恢复效果,提高系统的电压稳定性.     

计及暂态电压稳定性的自适应低频减载方案

根据电力系统的频率响应信息,提出一种发生扰动后系统实时不平衡功率的计算方法,补偿电压偏移造成的有功缺额影响.同时,考虑负荷节点的暂态电压稳定性,制定基于频率响应的自适应低频减载方案.通过在IEEE-39节点系统进行算例仿真,验证系统功率缺额计算的准确性以及自适应低频减载方案的有效性.结果表明,该方案可改善低频减载控制中的频率恢复效果,提高系统的电压稳定性.     

车辆离合器局部高温区成因及影响因素理论研究

摩擦副表面的局部高温区会引起车辆离合器失效,基于热弹性不稳定性（TEI）理论,通过理论建模与分析的方法,得到系统稳定性的判断标准:临界速度及其变化规律,以及系统扰动的迁移速度. 通过对摩擦片与钢片的Peclet数分析,发现局部向于出现在对偶钢片. 通过对比临界速度,发现钢片呈现反对称变形. 采用较小弹性模量或者较大导热系数的摩擦材料,有助于提高系统稳定性,摩擦材料的热膨胀系数对稳定性影响较小.      

基于贝叶斯决策的柔性作业车间扰动处理方法研究

为解决实际生产过程中扰动事件的多样性和不确定性问题.借鉴贝叶斯网络表示不确定性事物的方法,建立了柔性作业车间生产关系的贝叶斯网络模型;通过分析扰动事件对车间调度的扰动实质,提出了不确定扰动事件处理方法,并构建了扰动处理的3层结构流程图,实现调度系统对扰动的有效响应.仿真结果表明:与传统加工方案调度策略进行对比,基于贝叶斯决策的柔性作业车间扰动处理方法减弱和吸收扰动事件对调度系统的影响约为50%,从而有效地提高了实际生产效率.     

具有扰动的统一混沌系统的混合同步

研究了具有参数扰动和外部扰动的统一混沌系统的混合同步问题.基于Lyapunov稳定性定理,得到了两个混沌系统达到混合同步的条件.利用自适应控制方法,针对从动系统的系统参数未知的情形,设计出了控制器和参数自适应率;并对参数扰动和外部扰动的界限及从动系统的参数事先都未知的情形,给出了控制方案.最后,通过数值仿真验证了结论的正确性和有效性.     

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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