区间变时滞广义系统的稳定性分析(英文)

本文研究了区间变时滞广义系统的时滞依赖稳定性问题,即寻求稳定判据保证广义系统的正则性、无脉冲性和渐近稳定性。通过利用一个新的Lyapunov-Krasovskii泛函和自由权矩阵方法,得到了该系统渐近稳定的时滞依赖新判据。所提出的泛函,能充分利用区间时滞的上界、下界和这两个界中间值的信息。新判据以线性矩阵不等式形式给出,很容易利用MATLAB验证。数值算例表明,与参考文献中的方法相比,本文结果可获得较大的允许时滞上界,这也验证了方法的有效性。     

区间变时滞广义系统的稳定性分析

本文研究了区间变时滞广义系统的时滞依赖稳定性问题,即寻求稳定判据保证广义系统的正则性、无脉冲性和渐近稳定性。通过利用一个新的Lyapunov Krasovskii泛函和自由权矩阵方法,得到了该系统渐近稳定的时滞依赖新判据。所提出的泛函,能充分利用区间时滞的上界、下界和这两个界中间值的信息。新判据以线性矩阵不等式形式给出,很容易利用MATLAB验证。数值算例表明,与参考文献中的方法相比,本文结果可获得较大的允许时滞上界,这也验证了方法的有效性。
     

变时滞中立系统的时滞依赖渐近稳定性分析

本文讨论了一类变时滞中立系统的时滞依赖渐近稳定性问题.通过利用Lyapunov-Krasovskii泛函(LKF)和自由权矩阵方法,得到了该系统渐近稳定性的时滞依赖新判据.交叉项间的联系由Leibniz-Newton公式给出.定理的推导没有利用模型转换和交叉项有界方法.由于结果以严格线性矩阵不等式形式给出,所以很容易验...     

一类中立型系统的渐近稳定性判据

利用Lyapunov泛函方法,对线性中立型时滞微分系统的稳定性进行分析,得到了系统渐近稳定的两个时滞相关判据,这两个判据用线性矩阵不等式表示,易于验证.最后通过一个实例验证了所得结果的有效性.     

广义时变时滞系统的时滞相关稳定准则

利用时滞分解方法和线性矩阵不等式工具,研究了一类具有时变时滞的广义系统的渐近稳定性问题,得到了广义系统正则、无脉冲和渐近稳定的时滞相关充分条件．进一步,利用Matlab软件中的LMI工具箱求解,得到保证广义时滞系统渐近稳定的最大可容许时滞上界．最后仿真示例表明本文方法的有效性和可行性．     

区间时变时滞广义系统的稳定性分析

研究了区间时变时滞广义系统的稳定性问题.通过构造新的Lyapunov泛函,使用时滞分割和自由权矩阵方法,以严格线性矩阵不等式形式给出了使得系统正则、无脉冲且稳定的时滞相关型稳定性新判据.数值实例表明了结果的有效性和较小保守性.     

具有分布时滞的非线性广义系统一致渐近稳定性准则

针对一类具有分布时滞的非线性广义系统,利用李雅普诺夫第二方法和广义系统的受限等价变换,给出一致渐近稳定性准则。首先,在假设具有分布时滞的非线性广义系统是正则、无脉冲的基础上,构造了新的增广Lyapunov-Krasovskii泛函(L-K泛函),在L-K泛函中加入了三重积分项以获得更多的时滞信息;然后,对L-K泛函求导后产生的积分项应用边界估值更为精确的Bessel-Legendre不等式(B-L不等式)进行处理,利用Lyapunov稳定性理论和线性矩阵不等式给出了具有分布时滞的非线性广义系统的一致渐近稳定性准则条件;最后,利用数值算例,通过Matlab中LMI工具箱求解,验证了所用方法的可行性和有效性。     

基于Wirtinger型积分不等式的线性时滞广义系统稳定性准则

为研究线性时滞广义系统的渐近稳定性问题,利用时滞分割法均匀分割时滞区间,构造包含多重积分的Lyapunov-Krasovskii泛函以充分利用各子区间的时滞信息,并利用改进的Wirtinger型积分不等式估计泛函导函数的更紧上界,进而建立判定系统渐近稳定的时滞相关充分条件.最后,通过对比3个数值算例的仿真结果,证明了方法的有效性和先进性.     

不确定变时滞非线性随机系统的鲁棒稳定性

探讨了同时具有分布时滞和离散时滞的凸多面体不确定非线性随机系统的鲁棒稳定性.利用随机Lyapunov稳定性理论和自由权矩阵方法,基于参数依赖的Lyapunov-Krasovskii泛函,获得了系统的时滞相关及参数相关的鲁棒稳定性的充分条件,并以线性矩阵不等式的形式给出了系统的稳定性判据.最后用算例说明了文中方法的有效性.     

具有时变时滞的离散时间随机神经网络的时滞相依稳定性分析

研究了一类具有时变时滞的离散时间随机神经网络的稳定性问题.通过构造包含更多交叉项的新的Lya-punov泛函,将时滞区间等分为两个子区间,根据时滞函数所处不同的子区间更加细致地讨论了Lyapunov泛函中相应项导数的上界,利用不等式技巧,自由权矩阵和凸组合方法得到系统均方全局指数稳定新判据,结果具有更低的保守性,并举例说明了本文方法的有效性.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-