基于系统可靠性评估的机组检修规划模型

为确定市场环境下发电容量充裕度较低系统的机组检修计划,在分析其对系统运行成本影响的基础上,提出了基于系统可靠性评估的规划模型.该模型以规划期内系统总运行成本最小为目标,考虑各时段系统失负荷概率约束、运行约束及检修约束后,确定各机组检修时段,其中系统可靠性指标由蒙特卡洛模拟法评估.与其他模型相比,该模型考虑了双边合同及日前市场、机组及线路故障对检修计划的影响,并将系统可靠性水平转化为经济指标加以衡量.算例分析表明,该模型优先规划对系统可靠性影响大的机组,可确保系统各时段失负荷概率在指定范围内及整个检修计划的经济性.     

基于混合粒子群优化算法的机组负荷最优调度

粒子群优化(too)算法是一种现代启发式算法,提出一种基于混合粒子群优化算法的机组负荷的调度方法,该方法考虑了机组的经济性和安全可靠性.优化了机组的调度运行方式.     

计及输电阻塞的发电公司最优竞价模型

为了实现电力市场环境下发电公司最优竞价,根据对市场内其他机组报价系数的预测,建立计及竞争对手报价的发电公司竞价模型,求取未计及输电容量约束时的最优竞价系数.建立市场出清模型,计算各机组出力期望值,根据上述期望值进行潮流计算.当预测有输电阻塞发生时,将输电阻塞对电力公司竞价策略的影响引入竞价模型中,并基于灵敏度分析以阻塞费用最小为目标确定发电公司出力调整量.通过Matlab仿真分析表明,采取上述方法得到的最优竞价系数进行报价时,能实现发电公司利润最大化的目标.     

火电机组经济性诊断系统的开发

在当前国家能源供应十分紧张的情况下,提高火力发电行业的节能意识,加强能源管理,降低煤耗具有十分重要的意义。因此,建立完整的火电机组经济性诊断理论和有效的节能诊断工具,进而找出节能潜力的大小和场所,才能有的放矢的采取措施,提高机组的运行经济性。运用火电厂节能诊断理论,以机组实际运行的DCS数据为依据,考虑了火电机组的负荷特性、环境特性和热力系统结构特性,建立了火电机组经济性诊断的模型。根据经济性诊断模型,基于Microsoft Visual Basic 6.0开发了通用的火电机组经济性诊断系统,实现对机组的运行参数、热力系统运行方式及热力设备运行、锅炉运行进行全面诊断,以确定机组最好运行水平。     

考虑发电容量约束的完全信息电力市场中电厂机组竞价策略

在完全信息电力市场中,电厂如何制定机组的报价曲线是其能否成功竞价上网的关键。讨论了基于机组发电容量约束条件下,在弹性电力需求的完全信息电力市场中机组上网的竞价策略。该竞价策略在研究机组竞价模型的基础上,利用计算机编程求取电厂机组的最优发电量并获得最大利润的报价曲线,进而分析了在边际成本变动条件下的各电厂机组竞价策略。     

浅谈在电力市场下的发电调度问题

结合我国电力市场建设的实际,分别针对全电量竞价模式和部分电量竞价模式分析了竞价开机、合同开机2种机组开停机规约;为协调发、购电双方的利益要求,提出了根据竞价机组可用发电量的比例或竞价上网电量的比例等2种在发电公司(厂)内部分配各竞价机组合同电量的方法;为协调边际机组间的边际负荷分配问题,提出了比例分配法、依次分配法2种分配边际负荷的基本方法;根据机组发电计划的组成特点,提出并分析了日合同计划不可调、日合同计划可调2种机组发电计划调整规约。     

论火力发电厂机组运行方式的优化

火力发电厂机组运行方式决定着电厂运行的经济性和安全性。首先介绍了调度对机组负荷控制指令的形成,然后分析了四种常用的电厂机组运行控制方式,最后基于自动发电控制理论探讨了机组运行方式的优化,指出在协调控制系统CCS和自动发电控制AGC基础上,一定要注重整个优化机组运行方式,建立更加全面的机组协调控制系统。     

潮汐电站机组变速运行特性研究

针对潮汐电站水头变化频繁且变幅大、水轮机长时间偏离设计工况运行造成的机组运行效率和发电量低的问题,本文提出了一种变转速潮汐水轮发电机组,阐明了机组变速运行特性,分析了其效益。首先,基于水轮机模型综合特性曲线获得了其变速运行最优特性,在此基础上明确了机组在各水头和出力下最优转速的计算方法,为机组变速运行的控制提供了依据。其次,以江厦3号机组为例分析了机组变速运行的水轮机效率变化情况,机组正向运行效率最大提高23.39%,反向运行效率最大提高33.55%,说明变速运行可提高运行效率并改善运行工况。最后,比较了潮汐电站典型潮汐周期内机组变速运行发电量的变化情况,江厦电站3号机组发电量提高约3.65%,其中正向发电时长延长3 min,发电量提高0.97%,反向发电时长延长8 min,发电量提高10.40%,说明机组变速运行可延长发电时长、提高发电量。结果表明:机组变速运行是提高潮汐电站机组综合效益的有效途径。     

超临界供热机组凝汽器补水雾化方案优化研究

超临界供热机组将凝汽器的正常运行化学补水通过喷嘴雾化处理后以一定角度补入凝汽器中可以有效提高机组热经济性。通过这种技术可以有效提高补水换热效率,提高机组真空,大幅度降低凝结水过冷度,从而有效降低凝结水中溶氧量进一步提高低压回热系统热经济性,优化超临界机组运行经济性指标,最终达到降低机组发电煤耗目的。     

600MW直接空机组主要技术经济指标分析

直接空冷是空冷技术的发展方向,分析直接空冷机组主要技术经济指标并进行节能降耗研究对提高直接空冷机组运行经济性具有重要意义。以内蒙古某发电有限公司600MW等级直接空冷机组为例,对供电煤耗率、厂用电率、汽轮机热耗、真空度、节水量等5个方面的指标进行了分析,初步指出了影响以上技术经济指标的因素,并结合直接空冷系统的特点提出了初步的防治措施,对提高直接空冷机组运行经济性有一定的指导作用。     

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).     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.