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.     

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.     

A computer generator for randomly layered structures

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

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。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

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

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

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.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.