除氧器旋膜管冷态试验结果分析

本文对除氧蒸发器膜式喷管的冷态试验进行了分析,通过对试验结果的汇总,提出了产品设计中应采用的旋膜喷管规格尺寸。     

胶管胶带行业当前运行情况分析及利用高新技术和先进装备淘汰落后产能的建议

分析我国胶管胶带行业当前的运行情况。2013年胶管胶带行业销售收入同比保持微幅增长,增幅走势趋平。提出利用高新技术和先进装备淘汰落后产能使胶管胶带行业健康发展的观点,介绍了与胶管胶带行业关系密切的高新技术和先进装备,并就利用高新技术和先进装备淘汰胶管胶带行业落后产能提出了建议。     

大跨度复杂空间桁架焊接变形控制

某大型体育馆屋面采用大跨度空间钢结构,针对钢结构跨度大(双向均超过100 m),结构体系复杂,桁架焊接变形控制难度大等难点。在深化设计阶段、工厂加工阶段和现场焊接阶段进行全程控制,使焊接变形得到有效控制,桁架安装精度符合设计要求。     

用超细矿渣粉和硅灰配制高强、高性能混凝土的研究

通过实验研究掺入硅灰和超细矿渣粉配制高强、高性能混凝土,并对实验结果进行分析总结。     

RFID中间件技术在汽车装配线中的应用研究

针对现有汽车装配业的生产特点,分析了RFID中间件系统在装配线中的应用需求,构建了一套面向汽车装配线的RFID中间件应用系统架构,描述了RFID中间件的功用及典型结构。对整个装配线系统、RFID读写器管理、数据过滤及消息传送几大关键环节进行了详细的阐述。整个RFID中间件平台中采用JAVA技术开发。     

UHF RFID系统读写器控制处理模块硬件设计综述

控制处理模块是UHF RFID读写器电路的一个重要组成部分,该模块电路的设计及实现是当前UHF RFID系统一个研究的热点。基于此,对UHF RFID系统读写器的控制处理模块电路的组成结构、实现方式,特别是微处理器的选用进行了比较分析和综述,指出了基于SOPC设计理念、NiosⅡ嵌入式软核处理器的控制处理模块设计符合电子系统设计的发展潮流和趋势,具有市面上其它设计方案不可比拟的优势。     

Particle-in-cell simulation for effect of anode temperature on discharge characteristics of a Hall effect thruster

Propellant gas flow has an important impact on the ionization and acceleration process of Hall effect thrusters (HETs). In this paper, a particle-in-cell numerical method is used to study the effect of the anode temperature, i.e., the flow speed of the propellant gas, on the discharge characteristics of a HET. The simulation results show that, no matter the magnitude of the discharge voltage, the calculated variation trends of performance parameters with the anode temperature are in good agreement with the experimental ones presented in the literature. Further mechanism analysis indicates that the magnitude of the electron temperature is responsible for the two opposing variation laws found under different discharge voltages. When the discharge voltage is low, the electron temperature is low, and so is the intensity of the propellant ionization; the variation of the thruster performance with the anode temperature is thereby determined by the variation of the neutral density that affects the propellant utilization efficiency. When the discharge voltage is high, the electron temperature is large enough to guarantee a high degree of the propellant utilization no matter the magnitude of the anode temperature. The change of the thruster performance with the anode temperature is thus dominated by the change of the electron temperature and consequently the electron-neutral collisions as well as the electron cross-field mobility that affect the current utilization efficiency.     

Simulation of the effect of a magnetically insulated anode on a low-power cylindrical Hall thruster

The intersection point of the characteristic magnetic field line (CMFL) crossing the anode boundary with the discharge channel wall,and its influence on thruster performance and the energy and flux of ions bombarding the channel wall,have been studied numerically.The simulation results demonstrate that with the increase in distance from the crossover point of the CMFL with the channel wall to the bottom of the thruster channel,the ionization rate in the discharge channel gradually increases;meanwhile,the ion energy and ion current density bombarding the channel wall decreases.When the point of the CMFL with the channel wall is at the channel outlet,the thrust,specific impulse,and efficiency are at a maximum,while the ion energy and ion current density bombarding the channel wall are at a minimum.Therefore,to improve the performance and lifetime of the thruster,it is important to control the point of intersection of the CMFL with the channel wall.