电压型PWM可逆整流器建模与系统仿真

根据开关函数及状态空间理论建立了电压型ＰＷＭ可逆整流器的开关函数模型。通过对开关函数求傅里叶级数，将开关函数模型分解为高频和低频两个模型，从而求得整流器的状态空间平均模型。分别就开关函数模型和状态空间平均模型对ＰＷＭ可逆整流器进行了系统仿真，仿真结果证明了所建模型的正确性     

电压型PWM可逆整流器建模与系统仿真

根据开关函数及状态空间理论建立了电压型ＰＷＭ可逆整流器的开关函数模型。通过对开关函注傅里叶级数，将开关函数分解为高频和低频两个模型，从而求得整流器的状态空间平均模型。分别就开关函数模型和状态空间平均模型对ＰＷＭ可逆流器进行了系统仿真，仿真结果证明了所建模型的正确性。     

基于Matlab的开关磁阻电机混沌运行状态分析

根据实测电机磁链数据，运用Matlab／Simulink仿真平台搭建了开关磁阻电机非线性仿真模型，在一种简单的开关控制算法下，仿真得到了系统不同参数条件下的周期轨迹和奇异吸引子图，通过采样模型输出时间序列数据，结合相空间重构技术恢复了系统相空间，计算得到了其最大李亚普诺夫指数和容量维数，计算结果证明了开关磁阻调速电动机混沌现象的存在，最后，对采样时间序列数据进行谱分析，分析结果证明了混沌貌似随机的特征，也为混沌在降低电磁干扰以及机械噪声方面的利用提供了一种参考依据。     

基于Matlab的开关磁阻电动机驱动系统非线性建模仿真

在分析开关磁阻电动机数学模型的基础上，借助于Matlab／Simulink建立了电流滞环控制、功率变换器、转子位置角计算等模块，将这些模块有机结合，搭建出了电流斩波控制方式下的开关磁阻电机驱动系统的非线性仿真模型．据此模型，针对一台四相8／6结构样机进行了仿真，仿真结果证明了该模型的有效性．该模型为分析和设计SRM控制系统提供了一种有效的工具．     

关于异步电动机变频调速系统的仿真方法

仿真法是加速研究、开发工作的捷径，本文对由电源侧变流器、逆变器、异步电动机组成的变频调速系统提出了一体化的仿真方法，并导入开关函数的概念，对于不同的开关状态建立了统一的微分方程组形式。这使整个系统的数学模型变得简洁、明快，并简化了仿真计算。     

基于车辆动态负载的开关磁阻电机驱动特性分析

为了研究车辆动态负载高度时变性和随机性对电动汽车用开关磁阻电机驱动系统影响特性并实现电机驱动系统性能评价分析,基于车辆行驶工况动态负载特性,在开关磁阻电机非线性数学模型及车辆动力学模型基础上,分别建立了电动汽车用开关磁阻电机驱动系统及电动汽车动态载荷仿真模型.并根据电动汽车行驶过程中2个典型工况对建立模型进行了实时仿真,得到了开关磁阻电机主要性能参数随车辆动态载荷变化的响应曲线.分析并评价了开关磁阻电机驱动系统在各工况下的动态驱动特性,仿真结果对电动汽车车型设计及改进具有很好的参考价值.     

开关磁阻电机模糊控制及dSPACE实时仿真系统研究

主要介绍了一种可用于开关磁阻电机（SRM）调速系统中的模糊控制器。文章不但介绍了具体的设计方法，还给出了基干dSPACE平台相应的实时仿真结果。仿真结果表明：作为SRM调速系统中的这种模糊控制器具备很好的调速性能。     

开关磁阻电机调速系统功率变换器的仿真与研究

给出开关磁阻电机双开关型、公共开关型和星点型三种功率变换器的拓扑结构,分析了功率变换器拓扑结构结构特点及其工作原理。采用Matlab-Simulink软件建立了功率变换器的仿真模型,在不同脉冲信号的触发下进行系统的仿真,给出了开关磁阻电动机起动时的电流和电压曲线,并对仿真结果进行分析和研究,进而阐明了开关磁阻电机功率变换器拓扑结构的发展方向和应用前景。     

开关磁阻电机调速系统非线性仿真研究

利用有限元分析结果,并结合开关磁阻电机的基本方程,建立了开关磁阻电机非线性调速系统仿真模型。利用改进的一相电机模型,采用高速角度位置控制,低速电流斩波控制方式对开关磁阻电机调速性能进行研究。仿真结果表明该系统采用的控制策略合理,能实现较宽范围内调速。同时也验证了电机具有较好的起动能力和抗干扰特性。     

基于递推梯度控制的自适应智能开关控制器

对大惯性及纯滞后系统的自适应智能开关控制器给出了一种递推梯度形式的控制规律。分析了一种对温度进行控制的控制规律和实验结果,并进行了仿真研究。仿真结果表明,基于递推梯度控制的自适应智能开关控制器鲁棒性更优越。     

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…     

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。     

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).     

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.