一类金融投资系统的风险分析

运用动力系统稳定性理论,讨论了一类金融投资系统的稳定性问题.给出了系统在时滞脉冲下零解渐近稳定的条件,分析了系统参数、脉冲和延迟区间之间的相对关系.最后进行数值仿真,验证了时滞脉冲稳定的有效性,并给出了经济学解释.     

分数阶非线性变时滞脉冲微分系统的有限时间稳定性

论文研究了一类具有Caputo导数的分数阶非线性变时滞脉冲微分系统的有限时间稳定性问题,利用系统解的结构和广义的Gronwall不等式给出了具有时变时滞的分数阶非线性脉冲微分系统在有限时间区间上稳定的充分性条件,推广了现有结论,同时给出了具体的数值算例以验证定理条件的有效性。     

微分代数系统时滞依赖稳定性分析

采用线性矩阵不等式的方法,研究了一类微分代数时滞系统的稳定问题,得出了微分代数系统时滞依赖的稳定性条件,验证了微分代数时滞系统解的惟一性、无脉冲性及稳定性.     

一类非线性时滞系统的模糊变结构控制

结合模糊逻辑和变结构控制讨论了一类非线性控制系统的稳定性,利用模糊逻辑逼近一类非线性时滞系统,然后对模糊系统设计变结构控制律,达到了对非线性时滞系统的稳定控制．在理想滑动模的条件下利用线性矩阵不等式给出了时滞系统闭环稳定条件．     

基于LMI的时滞细胞神经网络的指数稳定性分析

研究了一类具有时滞的细胞神经网络的指数稳定性问题,利用Lyapunov Krasovskii函数,给出了系统全局指数稳定的时滞相关稳定性条件,其结果以线性矩阵不等式的形式给出,可以很容易求出系统稳定的时滞上界,并且能够达到时滞无关指数稳定性和全局渐近稳定性.数值算例说明了本文结果的优越性.     

一类非线性脉冲时滞微分系统解的指数渐近稳定性

利用推广的Dini导数脉冲微分不等式和Lyapunov函数方法研究了一类非线性脉冲时滞微分系统解的指数渐近稳定性，并给出无脉冲扰动下此系统解一致稳定的一个判定准则，尤其突出了脉冲效应对系统稳定性所起到的关键影响．     

一类时滞中立型脉冲系统的稳定性分析

探讨了一类时滞中立型脉冲系统的全局指数稳定性问题.基于李雅普诺夫稳定性理论,运用线性矩阵下等式技术给出了系统的全局指数稳定性的充分条件,并利用该理论可进一步分析其它中立型脉冲时滞系统的指数稳定性问题。     

一类具有时滞的不确定系统的鲁棒稳定性

利用Alekseev公式和Bellman-Gronuwall不等式,讨论了一类具有时滞的不确定中立型微分系统的鲁棒稳定性问题,给出了不确定系统在具有时滞的反馈控制下是渐近稳定的充分条件。     

基于LMI的时滞切换系统的稳定性分析

研究一类子系统为时滞系统的切换系统渐近稳定性问题.以线性矩阵不等式的形式提出了在任意切换信号作用下系统渐近稳定的充分性条件,给出了系统渐近稳定的凸组合条件以及切换信号的选取.仿真实例证明了所设计的切换方案的有效性.     

不确定时滞脉冲切换系统的保性能控制

研究了一类参数不确定性和定常时滞的连续的脉冲切换系统在任意切换下的保性能控制问题.利用Lya-punov稳定性理论与线性矩阵不等式方法,给出了连续的脉冲切换系统的保性能控制器存在的充分条件,并把这个条件转化为一个线性矩阵不等式,便于实现.     

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