多输入非线性时滞系统的同时H~∞控制

将单输入无时滞系统的相关结果,推广到多输入非线性时滞系统,设计了一个H~∞状态反馈控制器,用来同时镇定一族多输入非线性时滞系统.引入储能泛函的概念,提出构造时滞系统储能泛函的一种方法,给出同时H~∞状态反馈控制器存在的一个充分条件及其构造公式.     

饱和非线性约束离散时间系统的H_∞控制

研究了一类带有饱和非线性状态约束的离散时间系统的H_∞控制问题.根据Lyapunov稳定性理论和线性矩阵不等式(LMI)处理方法,提出γ-次优H_∞状态反馈控制律存在的一个充分条件,通过求解相应的线性矩阵不等式给出了H_∞状态反馈控制器的设计方法.数值算例验证了文中所提方法的有效性.     

De时滞大系统的分散H_∞ 控制器设计——LMI方法(英文)

研究了具有N×N个任意未知常时滞的线性连续大系统的分散H∞ 控制器的设计问题 ;给出了使系统渐近稳定且具有H∞ -扰动抑制度γ的分散H∞ 状态反馈控制器存在的充分条件 .该条件以线性矩阵不等式的形式给出 ,因而具有数值易解性 .最后用一个示例说明分散H∞ 状态反馈控制器的设计 .     

时滞大系统的分散H∞控制器设计——LMI方法

摘要研究了具有N×N个任意未知常时滞的线性连续大系统的分散H∞控制器的设计问题;给出了使系统渐近稳定且具有H∞-扰动抑制度γ的分散H∞状态反馈控制器存在的充分条件.该条件以线性矩阵不等式的形式给出,因而具有数值易解性.最后用一个示例说明分散H∞状态反馈控制器的设计.     

分散H∞状态反馈控制器的设计

对具有N×N个任意未知常时滞的线性连续大系统,研究了关联矩阵在一般分解条件下的分散H∞控制器的设计问题,给出了分散H∞状态反馈控制器存在的充分条件,该条件以线性矩阵不等式的形式给出.文中用一个示例说明了分散H∞控制器的设计.     

一类T-S模糊广义系统的非脆弱H_∞控制

在状态空间下,针对一类T-S模糊广义系统,研究了其具有反馈增益变化的H∞状态反馈控制器的设计问题,即设计的控制器当自身受到外部扰动时仍能完成对系统的镇定并满足H∞性能.利用Lyapunov稳定性理论,采用线性矩阵不等式(LMI)的处理方法,提出了T-S模糊广义系统的非脆弱状态反馈H∞控制器存在的充分条件,并进一步给出了保证T-S模糊广义系统H∞性能指标的非脆弱状态反馈控制器的设计方法.数值仿真表明该方法的可行性和优越性.     

分散H∞状态反馈控制器的设计

对具有N×N个任意未知常时滞的线性连续大系统 ,研究了关联矩阵在一般分解条件下的分散H∞ 控制器的设计问题 ,给出了分散H∞ 状态反馈控制器存在的充分条件 ,该条件以线性矩阵不等式的形式给出 .文中用一个示例说明了分散H∞ 控制器的设计 .     

基于积分型模糊Lyapunov函数的T-S模糊系统H∞控制

研究了连续T-S模糊系统H∞状态反馈控制器的设计问题.主要目的 是针对连续T-S模糊系统设计H∞状态反馈控制器,使得闭环控制系统渐近稳定并且满足给定的H∞性能指标.通过应用积分型模糊Lyapunov函数方法并结合有效的矩阵变换技术引入松弛变量,以线性矩阵不等式的形式给出了两个H∞状态反馈控制器存在的充分条件.最后通过仿真算例验证了所提出方法的有效性.     

不确定Delta算子时滞系统鲁棒H∞控制器设计

对一类由Delta算子描述的不确定时滞系统的鲁棒H∞状态反馈控制器设计问题进行研究,以线性矩阵不等式(LMI)形式给出控制器存在的条件,通过求解LMI得出控制器参数.最后以数值例子来说明该设计方法的有效性和可行性,所设计的H∞状态反馈控制器不但保证对象参数不确定时闭环系统渐近稳定,而且具有所期望的H∞性能指标.     

具有时变不确定性的广义系统的鲁棒H∞控制

研究具有一般形式的不确定广义系统的鲁棒H∞状态反馈和动态输出反馈控制器的设计问题·基于广义二次H∞性能概念,利用线性矩阵不等式,首先证明了如果存在鲁棒H∞动态状态反馈控制器,则必存在鲁棒H∞静态状态反馈控制器,然后给出鲁棒H∞静态状态反馈控制器存在的充要条件及构造方法,最后给出鲁棒H∞动态输出反馈控制器存在的充分条件以及相应的控制器构造·     

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.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the