电网铝合金3D打印产品性能研究

为研究金属材料3D打印技术在电网金属部件修复与制备领域的应用前景,使用硬度测试、拉伸强度测试、冲击试验、弯曲强度测试、腐蚀试验、导电试验等测试方法,进行了激光选区熔化(selective laser melting,SLM)工艺制造的电网设备部件样品与传统铸造工艺制造的电网设备部件性能比对试验,试验结果表明3D打印产品具有较高的硬度、强度和耐腐蚀性,但其塑性韧性较低。产生差异的主要原因是SLM工艺使用激光熔化产生的局部金属熔池与传统铸造大熔池冶金过程不同,以及熔池成型冷却速度不同,导致形成不同的金相组织从而表现出性能上的差异。因此金属3D打印技术制造的电网设备部件应使用在强度和环境适应性要求较高而韧性要求较低的部位。     

岳阳地区电网设备金属失效分析及防治应对

正电网设备金属材料的运行状态直接影响整个设备的安全可靠性,而其在设计选型、生产制造、装配调试及日常运行全过程中若存在差异或发生变化会影响设备的机械、电气性能,电网设备金属材料失效严重时将会导致设备的非计划停运及人员伤亡事故发生。在电网设备服役各阶段落实有关金属技术标准和预防设备事故措施,根据发现的问题提出针对性防治应对措施,能避免电力生产人员或设备的损失,保障电网安全经济运行、向用户提供优质服务。国网岳阳供电公司通过分析岳阳电网设备金属失效特点、规律,发掘设备金属失效的产生原因,     

青海电力公司支柱瓷绝缘子断裂事故情况及原因分析

支柱瓷绝缘子是电网结构的重要组成部分之一 ,近年来全国其它电网相继出现了支柱瓷绝缘子断裂事故 ,青海电网现有支柱瓷绝缘子由于受运行年限和环境等因素的影响 ,在运行中出现了一些问题 ,文章就近年来对发生在青海电网中的支柱瓷绝缘子断裂事故进行分析 ,并提出了相应的措施。     

电网事故处理辅助决策系统在区域电网的应用

电网事故处理辅助决策系统提供了主变故障、母线故障、线路故障、35kV及以下母线电压异常等的处理决策参考,有利于提高电网事故处理效率,减小事故对电网的影响。介绍了系统软件设计框架、系统模块以及系统设计理念。实践证明,合理使用该系统可减轻调度员日常工作强度,提高调度安全运行管理水平。     

高速永磁电机转子护套张力缠绕激光加热成型过程多物理场耦合分析

随着舰船综合电力系统对电机转速和功率需求的不断增大,传统非导磁金属材料已难以满足大功率高速永磁电机护套机械强度要求,热塑性复合材料强度高、涡流损耗小、护套厚度也远小于金属护套,具有良好的发展前景。该文通过建立热塑性复合材料(T700/PEEK)激光加热成型过程三维温度-流体-运动多物理场耦合分析模型,考虑热塑性树脂熔化相变过程,提出预浸带截面运动速度+力学载荷边界结合局部圆柱坐标系的方法,解决了大张力载荷预浸带缠绕等效模拟难题,实现了考虑材料非线性的大张力缠绕高速电机转子复合材料护套成型工艺过程的多物理场耦合模拟。通过实验测试的温度与仿真结果对比,验证该文建立的多物理场耦合仿真模型的有效性。该研究所得结论对完善高速永磁电机转子复合材料护套张力缠绕工艺具有一定参考价值。     

县级电网反事故演习分析

随着家用电器的广泛使用,越来越多用电设备进入了普通百姓家庭,这就无形中增大了电网的压力。尤其是近些年,各类电网事故层出不穷,为有效预防电网事故发生,县级电网调控部门要经常开展电网反事故演习活动,以此来增强公司各部门的事故处置反应能力,提高电网一线工作人员的综合素质,确保在电网出现事故时,公司各部门之间能快速开展工作,工作人员能快速、准确的处置事故,本文细致地分析了电网事故演习的各个细节,对反事故演习中的各个问题进行了探讨。     

大电网事故后的恢复处理方法初探

以华中电网的一次全网性反事故演习为例,结合分析大电网事故的特点,讨论了电网出现大电网事故后,如何进行大电网事故恢复处理的原则与方法。     

基于事故模型的监控信号智能分析算法

从各个电压等级的电网可能出现的典型事故出发,对电网的事故进行建模。通过模型匹配算法,能够对监控信号进行智能分析,自动判断电网中出现的事故。基于事故模型的监控信号智能分析算法能够适应各个电压等级、接线方式,并可适应不同的运行方式,对可能的事故进行准确辨别。包括监控信号对接、重要信号筛选、监控信号智能分析、分析结果展示几个模块,其中监控信号智能分析是重点。解决了以往监控信号量大、排列没有规则的问题,为调控运行人员提供了一个条理清晰、结果明确的事故分析平台。     

玻璃纤维复合材料拉伸试验及强度预测模型

为了探究单向玻璃纤维复合材料（glass fiber reinforced polymer,GFRP）的性能,采用2种成型工艺制备了GFRP,并进行拉伸强度试验,测定了GFRP的极限强度,研究成型工艺对其拉伸强度的影响。对传统单向纤维复合材料拉伸强度预测模型进行了改进,提出了基于纤维强度服从正态分布的单向纤维复合材料纵向拉伸强度预测模型。试验结果与模型预测结果对比表明,所提出的预测模型具有良好的精度。     

变电站金属材料大气腐蚀成因及腐蚀性污染物来源分析

针对河北省南部电网变电站金属材料的腐蚀情况,分析变电站金属材料发生大气腐蚀的影响因素及材料对大气腐蚀的敏感性,阐述大气中腐蚀性污染物的来源,提出防范变电站金属材料腐蚀的变电站选址和金属部件处理建议。     

失活SCR烟气脱硝催化剂再生工艺工业试验研究

SCR烟气脱硝催化剂在广泛使用的同时,失活催化剂大量产生。对失活催化剂进行再生,经济和环保意义重大。以某燃煤电厂运行了近25000h的失活SCR烟气脱硝催化剂为研究对象,在分析催化剂失活原理基础上,对催化剂再生过程中主要影响因素（压缩空气吹灰压力、超声清洗时间、清洗液硫酸浓度等）进行研究,并介绍失活催化剂再生处理步骤,包括清灰、预清洗、深度清洗、活性组分负载、热处理等。各类检测结果表明,采用所研发的方案进行再生,失活催化剂中碱金属、碱土金属及硫酸盐等污染物被有效清除,催化剂通孔率高达98.7%,比表面积明显恢复,相对活性提升至99%,抗压强度及单层催化剂SO₂/SO₃转化率符合使用要求,即失活脱硝催化剂各理化、工艺性能及其机械强度得到了有效恢复,可以再安装于脱硝反应器中继续使用。     

Pure rhenium metal

Discusses various properties of the metal rhenium. The properties include: malleability, high-temperature strength, resistance to carburizing and high electrical resistivity across a wide temperature range. This makes rhenium a great candidate for applications where high-temperature strength, wear resistance and erosion resistance is needed     

Contribution of metal vapor mass at periphery part of pulsed arc to electromagnetic force in weld pool

The arc welding has been used in various welding methods because it is inexpensive and high in strength after welding. However, it is a problem that accidents such as collapse of the bridge occur because of the welding defects. The welding of low cost and high productivity is required without the welding defects. The pulsed TIG welding is inexpensive and capable of high‐quality welding. The electromagnetic force contributing to penetration changes because the transient response of arc temperature and iron vapor generated from anode occurs. However, the analysis of pulsed TIG welding with metal vapor has been elucidated only metal vapor concentration near anode with transient phenomenon and heat flux. Thus, the theoretical elucidation of penetration depth with control factor has not been researched. In this paper, the contribution of metal vapor mass at the periphery part of pulsed arc to the electromagnetic force in the weld pool is elucidated. As a result, the iron vapor mass at periphery part decreased with increasing the frequency. The iron vapor was stagnated at axial center within one cycle. The electromagnetic force to the penetration depth direction in weld pool increased at axial center. Therefore, the metal vapor mass at periphery part plays an important role for the electromagnetic force increment at axial center.     

A rapid prototyping environment for teaching digital logic design

In this paper, the authors present a rapid prototyping environment for teaching digital logic design. Their primary goal was to build an FPGA based hardware prototyping system that provides sufficient flexibility for the implementation and functional verification of various digital circuit designs. Since the system is intended to be used as an experimental and demonstration board to support digital design courses and practices for the undergraduate students, it is simple to use and completely supported by the software for automatic implementation of digital circuits. The prototyping environment consists of a PC and the programmable board composed of 3 FPGAs. One FPGA is used to implement the digital circuit, while the rest of the devices implement an interface between the digital circuit and the PC. The PC is used for designing a digital circuit, automatic generation of the interface logic, programming the FPGAs and as a test engine for functional verification of the designed circuit. The presented environment is used in the regular educational process and the sample student projects are summarized     

GIL内金属微粒在直流电压下的运动特性分析

气体绝缘金属封闭输电线路(gas-insulated metal-enclosed transmission line,GIL)以其输送容量大、占地面积小、传输损耗小等优点,在许多场合是替代电缆和架空线路的首选方案。但GIL内部的金属微粒会在电场的影响下发生起跳和运动,严重威胁了GIL的绝缘性能。为更好地捕获金属微粒,掌握GIL内金属微粒的受力和运动特性是十分有必要的。本文首先忽略了盆式绝缘子对GIL轴向场强的影响,分析了金属微粒在同轴圆柱间的受力和运动特性,使用金属微粒谐振频率表征金属微粒在直流电压下的活跃度,并分析了电压和微粒半径对金属微粒谐振频率的影响规律。然后考虑了盆式绝缘子对GIL轴向场强的影响,得到了金属微粒的几种典型的运动轨迹。最后给出了对于金属微粒陷阱布置的建议,认为在盆式绝缘子凸面侧下方布置金属微粒陷阱是必要的。     

铅酸电池轻量化板栅的失效机理

为了提高铅酸电池的能量密度和寿命,发展轻量化的板栅以取代比重大的铅板栅,具有重要的实际意义.铅酸电池用轻量化板栅的失效主要是由板栅在电化学环境下腐蚀所引起的.因此,板栅在酸性条件下抗电化学腐蚀的能力对铅酸电池的性能和寿命有很大的影响.笔者总结了轻质金属板栅、轻质合金板栅和铅炭板栅的发展状况,以及其用于铅酸电池时的失效机...     

The effect of surface treatment using ceramic powder on adhesion properties in high reliability pressure sensor

An increasing number of pressure sensors are built in Si MEMS bridge structure using resistance devices. Recently, due to advance in autonomous driving and vehicles, numerous research in stability and sensitivity of pressure sensors have been conducted. In this research, metal diaphragm surface treatment characteristics, when MEMS devices are adhesived to the structure, to which pressure is transferred from the metal diaphragm, were studied. For surface structure shape, sand blasting process was used for the surface treatment. It is known that during the sand blasting process, adhesive strength increases with increases in penetration of the adhesive material and in surface roughness which results from an increase in powder sizes. However, based on the result obtained from this experiment, the uniformity of roughness determines adhesion, after a certain level of roughness is reached. Past a particular size of a SiC ceramic powder, adhesion shows decreasing trend because the thickness of adhesive materials decreases due to local variation in the surface. We could verify that in order to optimize the adhesion of the adhesive material from the sand blasting treatment, SiC ceramic powder sizes and treatment pressure need to be optimized.     

An Initial Model for Control of a Tandem Hot Metal Strip Rolling Process

The tandem rolling of hot metal strip presents a significant control challenge because of nonlinearities and process complexities. The challenge is heightened by an extremely hostile environment that precludes the location of sensors to measure process variables that are important for control. In addition, it is essential that the controller structure allows for a high degree of physical intuition in the design process and provides for simplicity of tuning during commissioning. Based on our previous work using a state-dependent Riccati equation (SDRE) technique for control of the tandem cold rolling process, it is considered that a similar method might also be useful as a basis for the development of a control technique for tandem hot strip rolling. For the hot rolling process, the development of a process model in a form that is suitable for use with a SDRE-based method is a significant and challenging task. This paper describes our work to develop an initial model for this process. Based on simulation results, it is determined that this initial model has the potential to be the basis for the development of the complete nonlinear model that can be used for development of a viable control method which offers the likelihood for improvement in the control of the hot metal rolling process.      

冻融循环作用下损伤砂岩物理特性研究

岩体破坏是其内部损伤积累发展的结果,在季节性温度变化作用下,岩体劣化程度加剧,使得寒区工程岩体发生失稳的概率大大增加。因此有必要对损伤岩样在周期性冻融作用下的劣化规律进行研究。本文在理论分析的基础上,对冻融过程中预加载损伤和无加载损伤的砂岩岩样,每次冻结、融化、低温烘干后各个岩样的纵波波速、电阻率这两个物理参数进行了测量,尤其还对岩样的电阻率进行了测定,并对这两个物理参数进行劣化度分析,结果表明:岩样的纵波波速与冻融循环周期呈二次函数关系,电阻率与冻融循环周期呈对数关系,且这两个物理参数对岩样的影响次序为:电阻率纵波波速。这就说明电阻率这个评价指标对岩样物理特性较为敏感,为工程评价寒区岩石的稳定性提供参考。     

锂离子蓄电池正极材料LiNi1-yCoyO2的研究

从材料的结构、合成、电化学性能、热稳定性和贮存性能几个方面综述了LiNi1-yCoyO2 材料近期的研究开发状况。LiNi1-yCoyO2 不仅具备了LiCoO2 的特性 (易合成、性能稳定 ) ,更兼有LiNiO2 的高比容量、低成本之优点。而且在充放电过程中LiNi1-yCoyO2 没有发生纯的LiNiO2 材料所经历的三次相变 ,因而具有较好的循环性能。同时LiNi1-yCoyO2的不可逆容量可以为负极SEI膜的形成提供Li源 ,从而减少正极的额外装载量。其它过渡金属离子对LiNi1-yCoyO2 的再掺杂 ,进一步改善了材料的稳定性。实践表明 ,以LiNi1-yCoyO2 为正极材料的锂离子蓄电池具有较好的综合性能