浅谈凝汽器夏季真空下降应对措施

在凝汽器全年运行期间,在夏季时都会出现凝汽器真空下降现象,严重的甚至真空达到真空低红线,对于大型汽轮机机组来说,如果凝汽器的真空度较低,不仅会降低机组运行的经济性,而且其安全性也会受到影响。所以探讨针对夏季时凝汽器真空下降应对措施,十分的有必要。     

600 MW双背压机组真空低分析及改进

通过分析大唐韩城第二发电有限责任公司一期2×600 MW机组的真空系统，找出了影响双背压机组低压凝汽器真空的主要因素，并提出了解决方法。     

浅谈凝汽式汽轮机真空下降的处理

现如今的许多工业领域运用的大型空压机组大部分已经运用了凝汽式的汽轮机,凝汽式的汽轮机的优点是在运行的过程中它非常的稳定,但是它的高效运行却为汽轮机的真空性提出了更高的要求。真空性强,凝汽式汽轮机就会高效率的运行;但是,当汽轮机的真空性下降的话,凝汽器汽轮机的工作效率就会很低。本文将会围绕如何控制好凝汽式汽轮机的真空度、如何处理凝汽式汽轮机真空下降等问题展开论述。     

真空变化对火电机组协调控制策略修正方法的研究及实现

真空是机组运行监视的主要参数之一,它关系到机组的安垒运行,决定了机组的理想焓降、发电效率和出力能力.在以往的机组控制中,仅把真空作为机组的保护参数,而没有将真空变化对控制参数的影响考虑在内,使得机组在真空不同时控制调节品质相差较多.本文介绍了通过试验方法获取真空改变对机组运行状态的影响数据,增加协调控制中对真空的修正部分达到控制优化目的试验过程.     

基于神经网络的凝汽器变工况模型北大核心

汽轮发电机组冷端系统运行优化问题中,因凝汽器设备运行一段时间后污染结垢及设备老化而性能改变,传统的凝汽器变工况特性模型计算值与实际值偏差较大,影响优化效果。针对上述问题,以600MW汽轮机组凝汽器为研究对象,在大型历史数据集的基础上,采用BP神经网络建立了该机组凝汽器变工况特性模型,仿真结果表明机组背压的预测计算结果与实际数据误差在4.5%之内,大部分误差不超2.0%。基于上述模型对凝汽器变工况特性进行了计算及敏感性分析,结果表明机组背压对循环冷却水进口水温变化最为敏感,其次是负荷率变化,最后是循环水流量变化;在机组高负荷率和入口冷却水温较高时,增加循环水流量降低机组背压效果更加明显。     

汽轮机凝汽器真空控制系统设计

分析了电站汽轮机凝汽器的工作原理及过程,在此基础上建立了汽轮机凝汽器真空系统的简化数学模型,并推导了其相应的状态空间表达式。根据这一状态空间表达式参数不确定的特点,运用极点配置的方法进行了真空控制规律的理论设计与推导,提出了这个参数不确定系统渐近稳定的充分条件,求得了相应的状态反馈控制律。运用Matlab语言,对所设计的凝汽器真空控制律进行了数值仿真研究。仿真结果表明,所设计的控制律具有良好的控制效果。     

基于本体和事例推理的凝汽器真空故障诊断研究

根据汽轮机凝汽器真空出现故障的概率较高,而且引起故障的原因较多,故障表现征兆区别不大的特点,文中提出一种基于本体论和事例推理的汽轮机凝汽器真空故障诊断模型;在分析汽轮机凝汽器真空故障领域知识的基础上,定义故障本体、属性、关系、故障实例和规则,建立故障诊断知识库;研究基于领域本体的事例相似性检索匹配方法,对故障进行识别推理;研究结果表明该方法有效地表示故障知识之间的语义关系,为汽轮机凝汽器真空的故障诊断提供了一种更为有效的实现方法.     

凝汽器水位测量的改进

１　问题的提出 凝汽器是发电厂汽轮发电机组的重要设备，凝汽器热井水位是否正常对凝汽器的正常运行有重要影响。目前的凝汽器测量装置通常采用平衡容器和差压变造器进行测量（见图１）。但该方法存在一个致命缺陷是，在实际运行过程中，由于凝汽器本身为负压，且温度较高，平衡容器中的水难以冷凝，得不到补充，且容易因较高的温度和负压而蒸发，导致测量装置的正压头丢失，造成水位测量不准，甚至测不到水位。２装置的改进 针对这一问题，在珠海发电厂施工中，对测量装置作了改进（见图２）。将平衡器的水量从依靠自然冷凝改为从外部管道…     

热电联产机组汽机控制系统分析及仿真建模

该文利用STAR -90模块化仿真支撑系统对热电联产机组进行仿真建模。并对热电联产机组汽机控制系统进行了分析。机组仿真机可以对电厂运行人员及管理人员进行培训和考核 ,使受培人员能熟练掌握机组在各种条件下的启停过程和正常运行中的监视操作技术 ;使受培人员的应急能力及对机组运行的综合分析能力得以提高。可利用仿真机进行机组运行方式的优化和研究 ;对控制系统的设计、性能分析以及现场调试都具有重要意义。     

直流锅炉控制系统分析及仿真建模

利用STAR—90模块化仿真支撑系统对电站控制系统进行仿真建模。电站仿真机可以对电厂运行人员及管理人员进行培训和考核，使受培人员能熟练掌握机组在各种条件下的启停过程和正常运行中的监视操作技术；使受培人员的应急能力及对机组运行的综合分析能力得以提高。可利用仿真机进行机组运行方式的优化和研究；对控制系统的设计、性能分析以及现场调试都具有重要意义。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。