Controlling anonymous mobile agents with unidirectional locomotion to form formations on a circle

We study the circle forming problem in which a group of anonymous mobile agents are required to form a formation when moving on a given circle. The agents are constrained to move in the one-dimensional space of the circle only in the counterclockwise direction, but not the opposite way. Distributed, cooperative, sampled-data control strategies are designed that only take nonnegative values. We prove that the multi-agent system under such constrained control input can be guided to reach the prescribed circle formation asymptotically with the additional guarantee that no collision between agents ever takes place. The theoretical analysis is further validated through simulations.     

加强环冷机的技术改造 全面提升链窑的潜能

马钢第三炼铁总厂链窑生产线自2007年9月份投产以来,环冷机运行效果均不佳,出现了很多问题,严重地影响了链窑的生产。在对环冷机各部结构及存在的问题进行了认真分析后,采取了不同的改进方案并予以实施。实践结果表明,这些改进方案均取得了成功,环冷机的运行效果大大提升,在节能降耗的工作上取得了很好的效果。     

Numerical simulation of the influence of over fire air position on the combustion in a single furnace boiler with dual circle firing

The Computational fluid dynamics (CFD) code PHOENICS is applied to simulate and evaluate the combustion process within the furnace of a 1,000 MW dual circle tangential firing single furnace lignite-fired ultra supercritical (USC) boiler. The dependence on overfire air (OFA) positioning on the combustion process is studied. The results show that the highest temperature appears on the upside of the burner zone close to the front wall, and the high temperature zone rises with elevated OFA positions. However, the temperature field distributions are similar despite differing OFA positions. The char content near the rear wall is higher than that near the front wall, and below the furnace arch, coal particles concentrate towards the front wall. Also with elevated OFA positions, nitrogen oxide (NO _x ) concentrations at the outlet fall, but char content increases. In regard to NO _x emission and char burnout, the suggested optimal distance from the OFA center to the center of the uppermost primary air nozzle should be 6 meters. This work was presented at the 7 ^th China -Korea Workshop on Clean Energy Technology held at Taiyuan, Shanxi, China, June 26–28, 2008.     

开孔处应力集中系数的简化计算

由于各种工业和结构的要求,不可避免地要在压力容器上开孔并安装接管,开孔必然会造成器壁强度的削弱,其削弱程度的大小可通过应力集中系数的大小来体现。通过对平板上开小圆孔边缘处的应力计算分析,得出开孔处应力集中系数的简便计算方法。运用该方法可以准确的计算出球壳以及圆柱壳等壳体上开圆孔的应力集中系数,确定危险位置及应力的大小,为确保压力容器的安全提供必要的条件。     

GIS中基于Voronoi图的公共设施选址研究

首先介绍了Voronoi图的定义和其与GIS中公共设施选址有关的几个性质,然后提出了公共设施选址中满足最小覆盖圆原则的一种基于Voronoi图的设施选址优化算法,并给出了实验结果。     

Extraction of embedded and/or line-touching character-like objects

This paper presents a novel method of circle scanning to detect intersection regions and to extract embedded/line-touching character objects. After the unembedded/not line-touching character objects are trivially extracted, the big line structure is broken down into character-like and line-like segments. Connected component analysis is applied and character-like segments are separated from line-like segments. The character-like segments then pick up the belonging intersection patches to produce character-like objects, leaving the other intersection patches to the line-like segments. Thus the problem of extracting embedded/line-touching character-like objects are addressed.     

基于循环缓存和精确定时多线程数据采集

在工业测控和数据采集系统中，需要信号连续、可靠、实时，同时数据需要做些同步处理和显示。为此，本文结合循环缓存技术与Windows环境下精确定时技术，提出了Delphi开发环境下的多线程数据采集解决方案。     

腐蚀网格对板材性能影响的试验研究

网格应变分析(CGA)技术已被广泛应用于成形难易性评价、模具的调试与修整、冲压件成形质量判定、冲压成形失效分析、仿真结果验证等各方面.电化学腐蚀法是在板材表面蚀刻圆形网格的常用方法之一,这种蚀刻过程会使板材表面产生一定的损伤.为了研究这种损伤是否会对板材本身的力学性能产生影响,选取270,370,440,590 MPa等不同强度级别以及冷轧、热镀纯锌、热镀锌铁合金等不同表面镀层的铜板作为试验材料,进行了蚀刻圆形网格前后板材力学性能的对比试验.分析结果表明,因在板材表面蚀刻网格而造成的这种表面损伤,对板材本身的力学性能的影响并不显著.