高阶非线性系统零解的全局稳定性

研究了一类高阶非线性微分系统,通过建立适当的李雅普诺夫函数,得出了这类高阶非线性系统零解全局渐近稳定性较弱的充分条件。     

热线温度场稳定性的实验研究——李雅普诺夫指数和分形数

对热线温度场的稳定性进行了实验研究.得到了周期解和准周期解的自相关功率谱线.李雅普诺夫指数可以表征动力系统的形态.分形数则可以表征混沌程度.李雅普诺夫指数和分形数随参数的变化,定量地表征了非线性系统运动形态的演变,用实验数据计算得到该动力系统的李雅普诺夫指数LE_1>0,但LE_1《1,且LE_1→0,分形致为2相似文献   

一类混沌系统全局指数吸引集的新结果及应用

研究了一类新混沌系统的全局指数吸引集与全局指数同步的问题.首先,根据全局指数吸引集的定义及李雅普诺夫稳定性理论,在没有任何存在性的假设下,对于系统所给参数构造了广义正定、径向无界的李雅普诺夫函数簇,给出了新混沌系统的全局指数吸引集和正向不变集的新估计.其次,对于两个混沌系统,采用线性反馈同步方法给出了两个混沌系统全局指数同步的充分性代数判据.最后,通过数值仿真给出了系统的同步误差图,结果表明此方法是可行有效的.     

Logistic方程中的孤立子及其控制

通过差分方法对Logistic方程离散化，利用稳定性理论、李雅普诺夫指数方法对该离散系统进行动力学行为的研究，在研究中发现该系统随着参数的变化既有混沌解，也有孤立子解．通过特殊的反馈控制，将混沌解控制到孤立子解上，利用李雅普诺夫指数小于0，证明了系统的稳定性．从而从理论上实现孤立子控制，并且利用Matlab软件进行数值仿真，也从数值上实现孤立子控制．     

不变时滞线性系统的混沌反控制

针对一类具有不变时滞的线性系统,运用泰勒公式,得到系统最大李雅普诺夫(Lyapunov)指数的表达式,获得系统对初始条件敏感的判断依据.此外,构造合适的李雅普诺夫函数,基于泛函微分方程的有界性引理,得到关于系统的解有界的判断准则.结合系统敏感性和有界性的理论结果,获得不变时滞线性系统混沌化的充分条件.最后,数值仿真出最大Lyapunov指数随时滞参数变化的图形,并做出在相应时滞参数下的相图.仿真结果验证了理论结果的有效性.     

一类Lienard方程零解的全局稳定性

利用构造李雅普诺夫函数方法证明了一类Lienard方程的零解的全局稳定性.     

概周期驱动的二维分段线性范式系统的奇异非混沌吸引子

利用相轨迹图、最大李雅普诺夫指数、有理逼近等方法,探讨概周期驱动的二维分段线性范式系统是否存在奇异非混沌吸引子;通过改变控制参数,观察系统的相轨迹图中是否出现分形现象;通过计算最大李雅普诺夫指数,得到奇异非混沌吸引子;通过对比有理逼近图与相轨迹图,验证奇异非混沌吸引子的存在性;通过功率谱、相敏感函数和回归图对奇异非混沌...     

具有时滞及多扩散模型的渐近性

研究了具有离散、连续时滞及多扩散模型的渐近性,证明了在适当条件下,系统是持久生存的;通过构造李雅普诺夫泛函,得出了解具有全局渐近稳定性的充分条件,即若系统是周期系统,则存在惟一全局渐近稳定的周期解。     

关于一类三阶非线性系统全局稳定性

利用王联、王慕秋提出的三阶线性系统的李雅普诺夫函数,采用类比的方法,构造出李雅普诺夫函数,研究了一类三阶非线性系统的全局渐近稳定性,并得到各自零解全局渐近稳定的充分条件.     

一类非线性积分微分方程的概周期解

讨论一类非线性积分微分方程的概周期解,结合运用李雅普诺夫泛函、不动点原理和概周期函数的有界性,给出系统存在唯一概周期解的一组充分条件.     

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.     

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-