Results of lightning impulse tests for a 275‐kV full GIS substation

This paper describes the outline and results of the lightning impulse tests for a 275‐kV full GIS substation. The behavior of lightning surges is a very important factor for the rational design of substations and low‐voltage and control circuits inside the substations. For the above reason, we carried out lightning impulse tests for a new 275‐kV full GIS substation. In these tests, we measured voltage induced in low‐voltage and control circuits, transient characteristics of grounding grid, injected voltage and current waveforms, and so on. By investigating these data, we confirmed the behavior of lightning surges inside the substation. We also compared simulated waveforms by EMTP analysis with the measured waveforms. The simulated results agreed well with the measured results. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 46–58, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10230     

熔融碳酸盐燃料电池系统研究

全部采用国内易购的材料，研制出有效面积为336cm^2的NiO阴极和Ni-Al合金阳极及面积为900cm^2的γ-LiAlO2电解质板和双极板；采用62％Li2CO3 38%K2CO3熔融盐作为电解质，组装出由30个电池组成的千瓦级熔融碳酸盐燃料电池堆；在800小时连续运行试验中，电堆性能稳定。以摩尔组分为99．7％的H2为燃料气，空气中的氧气为氧化剂进行测试，单电池平均工作电压大于0．72V，最大电流密度达165mA/cm^2，最大输出功率达1080瓦。     

Activation characteristics and microstructure of composite hydrogen storage alloys prepared by two-step re-melting

In the present work, novel composites (x=0,5,10,30) for hydrogen storage were prepared by two-step re-melting and their activation characteristic and microstructure were investigated. The influence of Mg₂Ni content on the activation characteristics was analyzed by electrochemical method. With the increasing content of Mg₂Ni, activation characteristics and maximum discharge capacities of composites increase first and then decrease. The composite with 5% Mg₂Ni has the least cycle number for activation and the highest discharge capacity. It is activated after only 6 cycles (C_n=6) at room temperature and its maximum discharge capacity (C_max) reaches 274.4 mAh/g. However, the composite contained 30 wt% Mg₂Ni is difficult to be activated at room temperature. It is also found that it is easier to be activated for the composites at and than that at and , but their discharge capacity decay slightly at the condition of and . The XRD and SEM analysis show that, with the increasing Mg₂Ni content, the microstructure of the composites varies gradually from lamellar (x=5), acicular (x=10) to massive (x=30), and the activity of the composite declines as a result of the grain size of phase Mg₂Ni grows up.     

3kW射频板条CO2激光器功率稳定性的研究

为了解决3kW射频板条CO₂激光器在高功率工作条件下功率波动的问题,采用外光路转折镜调节方法对腔镜热畸变造成的光路偏移进行补偿。研究了基于芯片TMS320LF2407的脉宽调制器控制激光器注入功率的关键技术,设计了整形光路尾镜取样功率检测系统,并分析了外光路自适应调节系统的补偿原理。结果表明,整形光路尾镜取样功率检测系统与基准功率计的最大误差为±2.59%,其具有高线性度;采用PA 100/T 14型压电陶瓷微位移驱动器,对微动距离不超过54μm的自适应调节转折镜进行调节补偿,光束偏移不会超出空间滤波器的0.8mm狭缝宽度;调节补偿前后输出功率波动由18%降到2%,达到了由于腔镜热变形导致光束偏移的补偿要求,整形光束的旁瓣消失,获得最佳模式输出。此项研究对提高激光器输出功率稳定性具有一定的实用价值。     

S275低合金钢焊接接头的组织与力学性能

通过拉伸、冲击、硬度测试和金相检验等方法对S275低合金钢熔化极活性气体保护焊(MAG)焊接接头的力学性能与显微组织进行了研究。结果表明:采用JM一56焊丝对S275低合金钢进行焊接时,接头具有较好的抗剪强度;开45。坡口,拉伸后均断在离焊缝位置较远的母材上,焊接接头抗拉强度满足技术要求。焊缝组织晶内为细小密集的针状铁素体,有极少量珠光体,焊缝局部有魏氏组织;熔合区、过热区为沿晶界析出的块状先共析铁素体和向晶内生长的条状铁素体以及少量的珠光体;正火区组织为细小的铁素体和珠光体;母材组织为铁素体和珠光体,晶粒也比较细小。最后得出S275低合金钢用于转向架焊接构架是可行的。     

轨道客车3kW充电机技术方案概述

论文对一种轨道客车3kW充电机做出了简要介绍,从电气原理、机械结构两方面对此充电机的技术方案作出了概述,列出了部分技术参数。提出了应用于轨道客车上的一种充电机的技术方案。     

基于MSP430F247和TMP275的测温仪

介绍了一种TI公司最新推出的MSP430F247单片机,利用它自带的12C模块驱动FC总线的温度传感器TMP275。TMP275是一款具有高精度、低功耗的新型温度传感器。由于TMP275具有可编程功能,纤小的封装以及极大的温度范围,因而广泛应用于组建超小型温度测量装置。     

现行标准牌号Q235角钢性能的研究

Q235我国钢铁产品中产量最大的牌号,本文对北京首钢红冶钢厂Q235角钢大规模生产数据进行了抽样和统计分析,认为现行GB/T 700中的Q235牌号标准水平低实物质量高的现象应是普遍的,Q235浪费了宝贵的钢铁资源。本文提出了本企业标准牌号HQ275(Q235的代替牌号),并对其进行了对比评价和可行性分析。对GB/T700-1988修订提出了建设性意见,认为其应加紧修订和实施。     

Financial and energy impacts of compact fluorescent light bulbs in a rural setting

Within the context of a national campaign to replace GLS with CFLs, a pilot study was undertaken in Niha, Lebanon to replace around 1000 light bulbs. This paper reports on the detailed savings actually obtained by this project. Energy savings were found to be 8.3%. The obtained savings were lower than the theoretical savings expected mainly due to apparent lower time of use than expected prompting a more moderate advertised yearly savings. The beneficiaries’ attitude towards CFLs was assessed and the results indicate a general satisfaction and willingness to purchase CFLs. One major drawback has been the dissatisfaction with light intensity. The impact of the campaign on other village residents was assessed and the campaign was successful in convincing one third of the population to install CFLs and two thirds said that they intend to buy CFLs in the future. A new approach in the campaign for CFL promotion is suggested.     

Deposition of Ti-6Al-4V using laser and wire, part I: Microstructural properties of single beads

In this paper, the microstructural characteristics of Ti-6Al-4V single beads and their dependence on process parameters are addressed. Single beads represent the smallest - and therefore fundamental - unit of additive manufactured components. Bead-on-plates and single beads are produced using a 3.5 kW Nd:YAG laser and Ti-6Al-4V wire. Within 71 sets of process parameters laser beam power, welding speed, and wire-feed speed are varied. The microstructures are investigated by light and scanning electron microscopy, and are divided into several zones according to the thermal history underwent. Microstructural differences of the beads are correlated to the process parameters and discussed. The experiments reveal fundamental microstructural and process characteristics which are helpful for the repeatable and predictable manufacturing and understanding of multi-layered components.