基于灵活网架的分布式光伏电源准入容量研究

分析推导了分布式光伏电源接入区域配电网的影响,在此基础上,考虑主动配电网背景下的灵活网架,以一系列静态安全稳定指标作为约束,建立了分布式光伏电源准入容量求解模型。将单个以及多个光伏电源接入的情况分开求解,相应地分别采用基于二分法的枚举法以及混合智能遗传算法求解,保证了模型求解的高效性。利用所提模型、算法,对10 k V中压配电网的几种典型网架接线进行分布式光伏电源准入容量的计算、比较、分析,验证了方法的有效性,总结了相关规律,提出了建议。     

多元化分析视角下机械设计制造及自动化应用

本文简要概述了机械设计制造与自动化技术的基本内容与使用要点,重点从多元化分析的视角探究了机械设计制造与自动化应用在应用技术、应用领域以及应用优势的多元化特点,并提出了及时更新技术、加强技术宣传、完善共享平台以及引进培养人才的策略,以加强机械设计制造以及自动化的应用。     

基于双尺度柔性原型迁移网络的空间滚动轴承寿命阶段识别

针对变工况条件下样本分布差异较大、不同寿命阶段样本数量不均衡导致现有空间滚动轴承寿命阶段识别方法的寿命阶段识别精度较低问题,提出基于双尺度柔性原型迁移网络（Dual scale flexible prototype transfer network,DSFPTN）的空间滚动轴承寿命阶段识别方法。在所提出的DSFPTN中,构造双尺度柔性域感知模块并将其嵌入特征提取器来增强特征提取器对不同领域私有特征的探索能力,提高特征提取器对空间滚动轴承源域和目标域样本特征的学习能力;设计同域泛原型学习以防止跨域样本不加区分的特征学习和不正确聚类,增加两域异类样本的区分性;构建两域原型迁移机制来获得域不变原型,实现从源域原型到目标域原型的迁移;利用加载域不变原型后的双分类器对齐两域之间的分布并计算目标域待测样本与域不变原型之间相似度完成对空间滚动轴承目标域待测样本分类,该分类方式在不同寿命阶段样本数量不均衡条件下能提高对各寿命阶段样本的识别精度。地面模拟空间环境下空间滚动轴承寿命阶段识别实例验证所提出的基于DSFPTN的寿命阶段识别方法的有效性。总之,构建双尺度柔性域感知模块、同域泛原型、两域原型迁移机制和加载域不变原型的双分类器使得DSFPTN在样本分布差异较大以及不同寿命阶段样本数量不均衡条件下,仅利用空间滚动轴承源域的非均衡有标签样本就能对目标域待测样本进行较高精度的寿命阶段识别。     

Piezoelectric pump with flexible venous valves for active cell transmission

The development of organ-on-a-chip systems demands high requirements for adequate micro-pump performance, which needs excellent performance and effective transport of active cells. In this study, we designed a piezoelectric pump with a flexible venous valve inspired by that of humans. Performance test of the proposed pump with deionized water as the transmission medium shows a maximum output flow rate of 14.95 mL/min when the input voltage is 100 V, and the pump can transfer aqueous solutions of glycerol with a viscosity of 10.8 mPa·s. Cell survival rate can reach 97.22% with a yeast cell culture solution as the transmission medium. A computational model of the electric-solid-liquid multi-physical field coupling of the piezoelectric pump with a flexible venous valve is established, and simulation results are consistent with experimental results. The proposed pump can help to construct the circulating organ-on-a-chip system, and the simple structure and portable application can enrich the design of microfluidic systems. In addition, the multi-physical field coupling computational model established for the proposed piezoelectric pump can provide an in-depth study of the characteristics of the flow field, facilitating the optimal design of the micro-pump and providing a reference for the further study of active cell transport in organ-on-a-chip systems.     

某汽轮机转子损伤轴颈的应力分析及修复评估

某电厂660MW机组汽轮机在运行过程中,由于部件脱落,造成联轴器I轴颈附近处磨出一圈沟槽。采用有限元法对损伤前后的转轴进行了分析,应力云图表明,损伤后转轴的最大应力明显增大。根据损伤部位的几何结构,采用车削手段进行修复,修复后转轴的最大Von Mises应力减小了5%;最大扭剪应力减小了14%。但是损伤后的轴和修复后的轴在短路或非同期合闸载荷等极端工况下,轴系强度的余量明显偏小,应在实际运行中予以高度关注。     

Preventing wind turbine overspeed in highly turbulent wind events using disturbance accommodating control and light detection and ranging

Light detection and ranging (LIDAR) systems can be used to provide wind inflow information to a wind turbine controller before the wind reaches the turbine. Both fatigue and extreme load reduction are possible as a result; in this research, we propose a LIDAR‐based controller designed to prevent emergency shutdowns caused by rotor overspeed. This switching controller consists of a disturbance accommodating control (DAC)‐based baseline controller and a different DAC linearized about a reduced generator speed for extreme events, also referred to as an extreme event controller. Switching between the controllers was performed using linear interpolation over various transition times, depending on how early the extreme event could be detected. If a gust of wind is detected using LIDAR measurements evaluated by a one‐sided cumulative summation algorithm, a relatively long transition time can be used. Switching can also be based on a large output estimation error, ε_y, in which case the transition time is shorter. Once the extreme event passed, control is switched from the extreme event controller back to the baseline DAC. This switching controller resulted in fewer overspeeds when compared with the modified baseline controller, which is a gain scheduled DAC. By preventing overspeeds, the switching controller increased the mean power the wind turbine generated over a simulated 10 min period. Copyright © 2014 John Wiley & Sons, Ltd.     

祥升煤矿6号煤柔模混凝土沿空留巷技术研究与应用

为改善祥升矿沿空留巷技术,使矿井达到安全高效的生产要求。本文结合6号煤层工作面地质条件,借助数值模拟的手段对6202工作面煤层开采后的围岩运动进行模拟,在此基础上采用柔模混凝土沿空留巷工艺,对巷道支护参数进行了设计。结果表明,柔模混凝土沿空留巷技术在现场应用较好,围岩变形较小,回收了大量煤柱资源,增加了较大利润。     

镁合金铸轧机关节流道的设计

本文介绍了一种应用于镁合金铸轧机熔液传输的关节流道,流道与铸轧机组成四连杆机构,可满足铸轧机从水平到15°的倾斜角度,并方便铸嘴的调整,调整过程中坩埚无相对位移。是应用于镁合金铸轧机的一种新型结构。     

海上直驱风电发电机转子的防腐蚀应用

为了提高海上直驱风电发电机转子磁钢的防腐蚀性能,磁钢采用稀土钕铁硼永磁材料并对其进行可靠性试验,用聚氨酯灌封树脂和固化剂昆合制作的粘结剂灌封,再用高性能FRP复合材料粘贴,用聚氨酯面漆涂刷作转子磁钢的表面防护层.实践表明,转子磁钢安装时被整体包覆使其具有良好的海上防腐蚀能力.     

缓速器转轮铸造工艺的优化

针对缓速器转轮产品铸造生产中经常出现的变形以及砂眼、气孔的现象,分析了原工艺存在的问题,从型砂、冒口等方面对铸造工艺进行了优化并改善了装备条件。通过对生产过程中制芯、配模、熔炼、浇注和热处理等关键工序质量的重点控制,显著提高了铸件成品率和铸造质量,降低生产成本,并保持产品质量的稳定。