关于非线性时滞微分系统的R-K方法的稳定性

具有时滞微分系统的稳定性问题是近年来讨论的热门话题。迄今，有关时滞微分系统稳定性的概念和结论都仅限于常时滞问题且都只考虑定步变的情况。本文在此基础上对变时滞变步长的情况进行了研究，并证明了在变时滞状态下，具有代数稳定的非线性微分系统的Runge-Kutta方法（简称R-K方法）仍然是零稳定的结论。     

单自由度时滞系统振动主动控制

对单自由度时滞系统主动控制的最优控制方法和变结构控制方法进行了研究,给出了反馈增益的稳定性条件和最大时滞量的解析确定方法,并采用移相技术进行时滞补偿．算例结果显示,移相技术能够较好地对系统中的时滞进行补偿,时滞补偿变结构控制方法的控制效果优于时滞补偿最优控制方法．     

时标上的变时滞二维动力系统的振动性

利用广义Riccati变换和不等式技巧,讨论一类时标上具有两个变时滞的二维动力系统的解的振动性质,得到的振动定理既适用于变时滞二维动力系统,也适用于变时滞二维微分系统和差分系统及某些二阶时滞动力系统。     

基于LTR观测器的输入时滞系统的滑模控制

针对一类线性时滞系统且存在外部噪声干扰和参数不确定性问题,提出一种基于回路传输恢复(LTR)观测器的滑模变结构控制方法.为了简化时滞变结构控制器的设计,采用非奇异线性变换将输入时滞的线性系统转化为无时滞系统,并进行滑模变结构控制器的设计、理论分析及稳定性证明.仿真结果表明,该方法对时滞系统在噪声干扰和过程参数不确定性时系统状态快速达到稳态,得到的控制效果仍具有较好的稳定性.     

具变系数变时滞非线性中立型方程的振动性

建立了具变系数变时滞非线性中立型方程解振动的充分条件．当此类方程的所有系数和时滞变元都是常数时，所给条件是ｓｈａｒｐ条件．所得结论推广并改进了已知的一些结果     

模糊细胞神经网络系统鲁棒稳定性分析

采用Lyapunov稳定理论,通过构造Lyapunov函数方法研究具有变时滞模糊神经网络系统鲁棒稳定性,给出了具有变时滞模糊神经网络系统鲁棒渐近稳定性的充分条件.     

变时滞反馈控制的混合中立型随机延迟微分方程的指数稳定性

研究了变时滞反馈控制的混合中立型随机延迟微分方程(HNSDDEs)的指数稳定性。采用函数方法设置合适的变时滞反馈控制函数,得到了该系统的指数稳定性。对比已有的研究成果,本文的主要贡献是在变时滞反馈控制下对HNSDDEs的指数稳定性作了进一步研究。最后,给出一个例子证明了结论的有效性。     

一类时变时滞静态神经网络的指数稳定性

基于线性矩阵不等式方法建立了时变时滞静态神经网络的指数稳定判据.考虑到时滞变化率对稳定性能的影响,分别建立了仅依赖时滞上界的稳定判据和完全依赖时滞信息的稳定判据.所得到的稳定判据能够适应慢变时滞和快变时滞两种情况,具有适用范围宽、保守性小和易于验证等特点,并通过几个注释说明与现有的文献结果进行了比较.仿真示例验证了所得结果的有效性.     

变时滞反馈控制的混合中立型随机延迟微分方程的稳定性

研究了变时滞反馈控制的具有时变延迟的高度非线性混合中立型随机微分方程(NSDDE)的稳定性.通过Lyapunov函数方法研究了该随机系统LP的渐近稳定性和H∞稳定性.对比已有的科研成果,该研究的主要贡献是将反馈控制函数和系统本身的时滞从常时滞推广到变时滞.最后,用一个例子来证明结论的有效性.     

具有一般激活函数的变时滞并联限制细胞神经网络的全局稳定性

研究了具有一般激活函数的变时滞并联限制细胞神经网络的全局稳定性,通过构造合适的Lyapunov函数,给出了新的变时滞并联限制细胞神经网络全局鲁棒稳定的一个充分条件.     

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.     

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.     

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.     

A computer generator for randomly layered structures

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

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.     

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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