一种多输入系统极点配置问题的改进算法

给出了一种化多输入系统为单输入系统极点配置问题的改进算法,介绍了该方法的基本原理和求解步骤,和通常的方法相比较减小了计算量,并得到了反馈增益矩阵的一个含有任意参数的一般表达式,通过对任意参数的适当选择,不但能使闭环系统的极点任意配置,还可满足闭环系统的其他性能要求,通过两个算例,说明了结果的正确性和有效性。     

矩形广义系统的极点配置的一种方法

研究了矩形广义系统的有穷极点配置问题.提出了利用动态补偿器对矩形广义系统进行有穷极点任意配置的一种方法及一个充要条件,并且得出了此方法所能任意配置的有穷极点的数目是r r_c个。通过动态补偿,将矩形广义系统的有穷极点配置问题转化为正常系统的极点配置问题,使整个闭环系统实现正则,无脉冲,任意极点配置。     

反馈控制系统的参数化及应用

本文采用多项式矩阵分式表示法,给出了多变量单位反馈控制系统的参数化描述.该参数化保证了控制器传函为真,而且自由参数直接作为控制器的参数,从而便于指导设计.文中还提出了实现极点配置或使得闭环系统有指定分母矩阵的控制器的设计算法,它可使得被设计的控制器除实现极点或闭环分母矩阵配置以外,尚具有其它的功能.     

基于传递函数互质分解的闭环极点配置方法

应用有理函数的互质分解和保证闭环系统稳定的控制器参数化结果,讨论了SISO系统的极点配置问题. 进行适当的互质分解和选择参数化控制器中的自由参数,便能对连续和离散系统实现任意极点配置. 仿真表明,此方法具有较好的控制效果.     

线性系统极点正规配置问题

基于正规矩阵特征值对其元素变化的不敏感性,讨论线性系统极点的正规配置问题,即设计状态反馈控制律,将闭环控制系统极点配置到期望位置的同时使闭环状态矩阵为正规矩阵,从而达到增强控制系统的鲁棒性的目的.对于线性时不变系统,给出期望极点集可正规配置的充分必要条件及反馈控制律的一般表达式,并结合示例给出算法.     

一类广义系统极点配置的方法

基于广义线性系统的三种等价形式的相关定理,讨论了静态反馈控制对一类广义系统的极点配置,即分别讨论了选择什么P反馈控制和P-D反馈控制能除去该类系统的闭环系统的无穷极点,得到了该类系统的闭环系统有穷极点集;并且对这些有穷极点进行任意的配置时发现,在改善系统属性方面P-D反馈控制优于P反馈控制。     

低反馈增益矩阵的求取方法

本文讨论由闭环系统期望的极点配置来确定反馈增益矩阵,以及低反馈增益矩阵的求取方法.     

多输入线性系统极点配置问题的算法研究

极点配置是通过一个状态反馈矩阵的选取,使闭环系统的极点配置在希望的位置,从而使系统具有较满意的性能。对于多输入线性系统,状态反馈矩阵K的解不唯一,目前常用的设计方法都没有解决K的优化设计问题。将遗传算法引入基于Sylvester方程的算法中,优化反馈矩阵,仿真结果表明,该算法求出的反馈矩阵K优于其他各种方法。     

状态反馈控制器对闭环极点的敏感性分析

本文利用隐函数理论，计算闭环系统的极点对反馈控制器K的偏导数矩阵，即闭环极点对控制器中的各个参数的变化率阵。从这个变化率阵我们可以了解到这些参数对闭环系统的极点的敏感程度，以便在实现控制器时，对那些敏感程度大的参数多加关照。     

不确定连续系统基于区域极点配置的鲁棒容错控制

利用代数Riccati方程和矩阵范数理论,研究了连续系统基于区域极点配置的容错控制问题。给出了系统闭路环极点配置在圆形区域内对执行器失效且具有完整性的一个充分条件;进而讨论了不确定连续系统的闭环极点配置在圆形区域内的鲁棒容错控制问题,且给出了此条件下鲁棒容错控制系统的设计方法。此设计方法是有效的。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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