Three-phase four-wire shunt active power filter based on the SOGI filter and Lyapunov function for DC bus control

The three-phase four-wire shunt active power filter (SAPF) was developed to suppress the harmonic currents generated by nonlinear loads, and for the compensation of unbalanced nonlinear load currents, reactive power, and the harmonic neutral current. In this work, we consider instantaneous reactive power theory (PQ theory) for reference current identification based on the following two algorithms: the classic low-pass filter (LPF) and the second-order generalized integrator (SOGI) filter. Furthermore, since an important process in SAPF control is the regulation of the DC bus voltage at the capacitor, a new controller based on the Lyapunov function is also proposed. A complete simulation of the resultant active filtering system confirms its validity, which uses the SOGI filter to extract the reference currents from the distorted line currents, compared with the traditional PQ theory based on LPF. In addition, the simulation performed also demonstrates the superiority of the proposed approach, for DC bus voltage control based on the Lyapunov function, compared with the traditional proportional-integral (PI) controller. Both novel approaches contribute towards an improvement in the overall performance of the system, which consists of a small rise and settling time, a very low or nonexistent overshoot, and the minimization of the total harmonic distortion (THD).     

料仓皮带机电子秤在烧结生产工艺中的应用--一种模块式计量托辊电子皮带秤的应用实践

烧结生产,是钢铁工业的重要环节。烧结矿生产的各种矿料、燃料、辅料配比和烧结矿成品需要称重计量。烧结料配料与烧结矿成品基本是采用皮带机输送,烧结矿生产物料适宜采用电子皮带秤计量。为简化电子皮带秤的结构,降低安装和维护工作量,可将皮带机的上托辊,采用模块式计量托辊代替,可组合组装成多段计量的电子皮带秤。模块式计量托辊,可安装到原皮带机或原皮带电子秤,替代原托辊或原计量托辊。简化电子皮带秤的结构和安装,减少安装与维护工程量。嵌入式计量托辊模块,为发明专利产品。     

自动电位滴定仪示值误差测量不确定度评定

按照JJG 814-2015规定,自动电位滴定仪需进行电计示值误差和仪器示值误差检定,本文例举对这两项检定结果进行不确定度评定,供相关人员参考。     

基于TRIZ理论滤咀排列鼓工装夹具优化设计

针对滤咀排列鼓工装夹具所存在的制造难度大,精度难于保证,效率低的问题。利用TRIZ理论进行分析,根据技术矛盾解决方法并结合问题的实际情况,获得了具体可行的解决方案。经过实践证明,此设计方案是可行的、可靠的,大大缩短了夹具的加工周期,提高了生产效率,节约了成本。     

能源互联网内多类设备协同运行的能量管理系统软件设计

针对能源互联网中的海量分布式设备和电动汽车的需求，利用C#和Java编程语言设计并开发面向能源互联网的能量管理系统。该系统采用典型B/S 架构，以Asp.Net动态网页开发技术和数据库技术为核心，由云端后台算法、云端服务器的MySQL数据库、前端的网页三大部分构成。详细介绍了软件平台的系统框架，分为上下两层。其中，上层为日前-实时协同的多时间尺度能量管理系统模块，下层包含分布式设备协调控制子系统和电动汽车协调控制子系统。最后，通过仿真算例分析，能量管理系统能对海量的分布式设备和电动汽车进行优化调度，验证了该软件的可移植性、有效性和实用性。     

40万t/年转炉钢渣蒸汽陈化处理生产线

介绍了针对国内某炼钢厂专门设计的40万t/年转炉钢渣蒸汽陈化处理生产线主要参数及工艺流程,对该生产线中的钢渣倾翻车、钢渣冷却搅碎车、转运车、蒸汽陈化釜等主要设备特点进行了阐述,同时对该生产线应用的冷却水量研究、搅碎辊轨迹优化等关键技术作了进一步的探讨。     

含芳香氨基酸三肽及其衍生物自由基离子的形成和解离机理研究

铜-配体(L)-三肽组成的三元复合物［Cu(L)M］²⁺，其中，L表示4′-氯-2,2′:6′,2″-三联吡啶(缩写为4Cl-tpy)；M表示酪氨酰-甘氨酰-色氨酸(YGW)及其修饰型三肽(CH₃CO-YGW-OCH₃，缩写 Ac-YGW-OMe)。使用该复合物，通过碰撞诱导解离 (collision-induced dissociation, CID)产生两种自由基离子 (［YGW］^·+和［Ac-YGW-OMe］^·+)。采用串联质谱结合密度泛函理论 (density functional theory, DFT)得到气相稳定结构，并研究其气相解离行为。研究结果表明，［YGW］^·+和［Ac-YGW-OMe］^·+的气相解离行为截然不同，［YGW］^·+主要产生［M-CO₂-116］⁺和［M-CO₂］^·+碎片离子；而［Ac-YGW-OMe］^·+在气相中主要产生［M-CH₃OH］^·+碎片离子。推测这两种离子的气相裂解机理分别为：［YGW］^·+羧基上的质子重排到多肽骨架中羰基氧上，经历 C_α-C键的断裂产生［M-CO₂］^·+、断裂色氨酸侧链 C_β-C_γ键产生［M-CO₂-116］⁺离子；［Ac-YGW-OMe］^·+则先经历质子重排到酯基氧上，然后经过C-O酯键的断裂形成［M-CH₃OH］^·+离子。参与重排的质子可能有3个来源：Ac-YGW-OMe中甘氨酸的C_α-H、色氨酸的C_α-H 或C_β-H，该机理有待进一步验证。本研究将为其他类型多肽及衍生物的结构及气相反应机理研究提供参考。     

Governance choices and policy outcomes in the Latin American and caribbean electricity sector

The paper first provides, for Latin America and the Caribbean, country-specific synthetic quantitative measures of the degree of adoption of governance reforms in the electricity sector, focusing on four key dimensions (market structure, private sector participation (PSP), regulatory autonomy and operational organization). These measures are then correlated with standard policy performance outcomes measures. The findings suggest that, the reforms, considered jointly, were statistically significantly associated with higher technical and process quality but not with social or service improvements. Considered individually, increased regulatory autonomy enjoyed the highest positive correlation with desirable outcomes, but PSP has no significant correlation with any of the outcomes. In sum, as of 2018, governance reforms, considered jointly, had still not delivered on some promised payoffs, notably in addressing energy poverty, although the sensitivity analysis suggests that, for some indicators, the relationships are stronger for larger than for smaller countries.     

User activities and the heterogeneity of urban space:The case of Dahiyat Al Hussein park

Urban researchers have maintained a constant interest in the complexity and continuity of urban space usage. Some have applied actor–network theory (ANT) to investigate the heterogeneity of spaces and present them through the networks of their users’ activities. However, these accounts are predominantly limited in examining the extent to which these spaces may be heterogeneous when exploring such networks. This paper draws on recent ANT scholarship, which employs an ethnographic research conducted in a main park in a housing project at Dahiyat Al Hussein in Amman, Jordan. The findings describe the complex and unpredictable negotiations that occur within spaces by documenting the varieties and interrelations among user activity networks within this common and shared urban space. This research reveals the extent to which spaces, parks in this case, may be heterogeneous by unpacking their usage. The conclusions and insights assert the necessity of paying attention to design detail and creating designs that are responsive to evolving user activities.     

基于ANSYS的双列圆锥滚子轴承预紧力有限元分析

应用赫兹弹性接触理论,首先分析双列圆锥滚子轴承的结构参数、预紧原理及其预紧受力,再运用SolidWorks建立了双列圆锥滚子轴承的三维模型,最后通过ANSYS进行有限元分析计算,得出在不同的预紧载荷下的接触应力和变形,为轴承预紧力分析提供了新的研究方法。