基于电子海图平台的多元异构数据融合研究

随着GIS的应用深入，对空问数据的需求越采越大，空间数据的大量重复获取不仅造成了人，财力巨大的浪费，而且还带来了空间数据的二义性问题。为了解决这一问题，提出了数据融合的方法。通过对空间数据融合，可以消除空间数据模型，物体的分类分级和几何位置的精度等引起的差异，为了实现空间数据的共享，扩大空间数据使用范围，减少空间数据的维护和获取费用。在深入研究IHO“数字海图测量数据转换标准”以及ARC／INFO，MAPINFO数据模型的基础上，探讨了符合IHOS-57V3．0的电子海图数据格式的融合的电子海图数据模型、并对多元异构数据的融合提出了一种实现方法。     

用CORBA提高ARC/INFO的并行计算能力

GIS已得到了较为广泛的应用,但由于处理速度的原因,不能满足对实时性要求较高系统的需求。本文提出利用CORBA对ARC/INFO进行并行化设计,充分利用多处理机的并行计算能力,提高GIS的处理速度,从而达到实时应用要求。     

New approach to determination of maximum temperatures in welding using travelling heat sources

Abstract

The present paper considers methods of calculation of maximum temperatures in welding using a constant welding speed and a point heat energy source. A comparison of theoretically obtained times for the occurrence of maximum temperatures with those obtained experimentally shows slight deviations. The latter are dependent only on the accuracy of temperature measurements and the workpiece size (i.e. plate size in the present work). In the present case, the limitations refer only to the workpiece size. The advantage of this new approach is in the determination of a plane curve which is an envelope of all the points in the workpiece that are simultaneously at the maximum temperature in arc welding.     

NDZ-20医用电子直线加速器的注入系统

文章介绍了NDZ-20医用电子直线加速器的束流注入系统的结构和特性。电子枪为轰击型的皮尔斯电子枪。漂移管上的预聚焦线圈、偏掉线圈、导向线圈和束流前沿切割线圈用来实现对电子束的多种控制,实现加速器的ARC,ADC和BLC运用,以保证加速器运行的稳定性和可靠性,改善反馈加速器的能谱。     

大空间建筑的语音清晰度解决方案——上海世博会主题馆广播系统介绍

大空间的语音清晰问题作为业界的一大难题,一直以来都没有一个很好的解决方案,在此试图通过世博主题馆的广播系统方案来分析、探讨在大空间建筑内解决语音清晰度的问题。     

气象雷达全固态调制器的几种故障排除方法

文章阐述了气象雷达全固态调制器的工作原理及其主要故障的分类,并针对气象雷达在业务运行过程中出现的调制器组件典型故障进行了分析,介绍了如何根据报警信息、故障现象进行定位和排除的方法。文章所述3例雷达故障现象不尽相同,但都与调制器组件相关,针对高压打火可能对发射机造成的严重危害,需要熟练掌握高压线路和模块组件线路结构及信号流程,才能更快更好的排除雷达故障。     

Observations of the phenomenon of abnormal arc voltage occurring in pulsed metal inert gas welding of aluminium alloy

Abstract

At the time of arc reignition after short circuiting during electrode positive polarity, cathode spots are newly formed in the centre of the weld pool surface, where oxides scarcely exist. The work function of the cathode surface increases and the cathode spots concentrate because of the lack of sufficient oxides, leading to an increase in the potential gradient across the cathode fall space and the adjoining contraction space. Consequently, the arc voltage becomes abnormally high in spite of the short arc length. Moreover, when electrode polarity is switched from positive to negative immediately after a droplet has detached from the wire tip, cathode spots are newly formed on the surface of the molten metal remaining at the wire tip, where little oxide exists, leading to an abnormal increase in arc voltage as well. Therefore, the change in arc voltage does not necessarily indicate a fluctuation in the arc length.     

证券行业IT系统协同工作的解决方案LinBox系统

LinBox系统是为证券行业“大集中”模式下IT系统协同工作而设计的解决方案。该系统通过定制的Linux操作系统、特别研发的LP中间件平台和ARC管理中心，组成一套LinBox技术系统。在此系统上，集成可管理的各种应用，从而实现低成本、低风险、易管理和高可用的目标。     

Gas tungsten arc welding of titanium using flux cored wire with magnesium fluoride

Abstract

Grade 2 Ti–CP was gas tungsten arc welded using flux cored (FC) wires and flux pastes that contained various MgF₂ contents. The effects of MgF₂ on bead morphology, chemical composition and hardness of weld bead were investigated and interpreted. With an increase of MgF₂ content in the flux paste, depth/width ratio of weld bead increased gradually with little variation in interstitial element contents and hardness. Weld bead made with cold FC wire feed showed even deeper and narrower bead, indicating the greater effectiveness of wire feed than flux paste on weld penetration. While the 50% MgF₂ FC wire produced complete slag coverage and smooth weld bead surface, 85% MgF₂ wire resulted in incomplete slag coverage and rough weld surface. Arc spectroscopy revealed that the 50% MgF₂ FC wire produced plasma spectrum with atomic and ionised titanium peaks, which is an indication of a high temperature arc and a larger amount of flux vapours in the arc. Therefore, it is believed that deep weld penetration associated with high MgF₂ fluxes in this experiment is caused by arc constriction, resulting from the greater amount of flux vapours owing to high arc temperature.     

基于电网模型的地理信息可视化实现

电网模型是描述系统全局运行状态的数据文件,针对ARC/INFO平台图形显示局限于离线关系数据库的现状,提出可交互电网地理信息可视化的实现方法。在研究CIM/XML模型文件作为电网地理参数的数据载体的基础上,通过关联的元件类来表达电力设备的实际属性,设计ODE接口的外部操作环境,实现电网拓扑关系的创建以及图形元素的绘制与显示。结合综合数据平台的在线应用表明,该方法有效减轻系统维护工作量并对电网实时运行表达有较高的准确度。