非线性广义系统的输入-状态稳定性

研究非线性广义系统的输入-状态稳定性问题.输入-状态稳定性是非线性控制系统的一个重要性质,基于非线性系统的输入-状态稳定性概念,给出非线性广义系统输入-状态稳定(ISS)的定义,并利用ISS-Lyapunov函数给出非线性广义系统输入-状态稳定的一个充分条件.     

非线性广义系统的局部输入-状态稳定性

利用 LISS-Lyapunov 函数研究非线性广义系统的局部输入-状态稳定性问题.根据局部输入-状态稳定性要求初始状态和输入在一定范围内变化,给出非线性广义系统的相应定义,得到非线性广义系统局部输入-状态稳定(LISS)的1个充分条件.     

大型互联线性系统的输入-输出分散有限时间镇定

借助于线性时变系统输入-输出有限时间稳定性的定义,对大型互联线性时变系统引入了输入-输出有限时间稳定性的概念。并对一类大型互联线性时变系统进行了分散状态反馈控制器设计,利用微分线性矩阵不等式（DLMI）的方法,提出一个充分条件,当反馈控制律作用于该系统时,闭环系统是输入-输出有限时间稳定的。并给出仿真算例说明该结论的可行性和有效性。     

样本的k阶中心绝对矩的依概率收敛性证明

利用辛钦大数定律和随机变量序列依概率收敛的性质,通过不等式的放缩技巧,给出了样本的k阶中心绝对矩依概率收敛于总体的k阶中心绝对矩的证明.     

2-D离散系统的输入－输出能量解耦

给出了2-D离散系统的能量解耦方法,即从输入-输出能量关系上对2-D离散系统进行解耦,使得任何一个输入的能量主要控制一个输出的能量.给出了2-D Roesser模型的能量解耦判据,并且用线性矩阵不等式来描述,求解方便.最后,给出了示例.     

线性广义系统的输入-输出能量解耦

考虑线性广义系统的输入 输出能量解耦问题,即从输入 输出的能量关系上实现解耦,使得任何一个输入能量主要控制对应的一个输出的能量,对其他输出能量的影响尽可能小·利用线性矩阵不等式,给出线性广义系统能够输入 输出能量解耦的充分条件,使得闭环系统具有上述性能,同时也是容许(即正则,稳定,无脉冲)的,并且基于线性不等式的解提出了相应的控制器设计方法,最后利用结果提出线性广义系统输入 输出能量解耦的算法并给出一个数值算例·     

一种迭代未知输入观测器设计

针对具有未知输入的线性系统讨论了基于迭代控制思想的未知输入观测器设计方法.针对每一步迭代,由于当前未知输入已知,因而可以通过设计常规的Luenberger观测器得到当前步的状态估计和输出估计.在此基础上采用D-型迭代学习控制的思想,通过当前输出步误差和未知输入估计值提出下一步的未知输入的迭代估计方法,并利用此次未知输入估计值再次设计Luenberger观测器估计下一步的状态.之后,对迭代算法的收敛性进行了分析,并给出了迭代算法收敛的充分条件.最后,对一个实际模型进行仿真,验证了算法的有效性.     

多输入多输出Volterra滤波均衡

为了从带有噪声的输出信号中恢复出输入信号，研究了多输入多输出（MIMO）Volterra滤波均衡器的设计问题，并给出了具体的设计步骤，讨论了当使用p阶阶逼近Volterra滤波均衡器代替无限阶Volterra滤波均衡器时的收敛性及误差界，引进了MIMOVolterra滤波器局部l^2稳定性的概念，利用多维z变换，给出了p阶逆的计算公式，然后研究了Volterra滤波均衡器的设计算法，并讨论了它的收敛性及误差界，仿真结果表明，所提方法不仅可以直接应用到多输入多输出系统，而且还可应用到阵列信号处理及无线通信系统中。     

基于观测器的不匹配未知输入系统的滑模控制

对具有不匹配时变未知输入的线性系统,研究了基于观测器的滑模控制器设计方法.首先,设计了一种与控制输入无关、能直接抵消未知输入影响的降维观测器.通过该观测器估计系统状态,并提出了一种未知输入代数重构方法,进而利用高增益滑模观测器给出了未知输入一阶微分的渐近估计方法.最后,提出了一种基于系统状态估计、未知输入重构及未知输入一阶微分估计滑模控制器新的设计方法,并通过仿真分析,论证了该方法的可行性和正确性.     

基于输出反馈的全输入-输出线性化系统的鲁棒渐近输出跟踪

研究一类全输入-输出线性化系统基于输出反馈的鲁棒渐近输出跟踪控制问题,如果一个带扰动的单输入-单输出非线性系统,其标称系统具有相对阶n,则通过系统状态的线性变换,可得到输出反馈控制律.当输出反馈控制律作用于该系统,扰动较小时,跟踪误差能小于设定的界ε*和渐近收敛于零.     

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