Failure of reinforced concrete and tuff stone masonry buildings as consequence of hydrogen pipeline explosions

Pipelines are the most efficient method of transporting large quantities of hydrogen, and the low volumetric energy density of gaseous hydrogen requires that the gas must be compressed to extremely high pressure to be used as a transport fuel. The failure of high pressure hydrogen gas pipelines and subsequent explosion may induce heavy damage to buildings. In this paper, such an issue is addressed for existing reinforced concrete framed buildings and tuff stone masonry buildings. Physical features such as the gas jet release process, flammable cloud size, blast generation and propagation, and explosion effects on structural components of buildings are considered and evaluated through the SLAB integral model, Multi-Energy Method and pressure‒impulse diagrams. Damage to both types of structural components was evaluated and the maximum distance of blast damage was derived in several environmental conditions, contributing to land-use planning and performance-based design/assessment of pipelines and buildings.     

电动汽车用高性能直驱轮毂电机研制

直驱轮毂电机因其作为分布式驱动电动汽车一种动力构型的诸多优点而广受关注。然而轮毂电机技术要求高,且多物理域深度强耦合,设计及制造难度大,我国尚无比肩国际的高性能轮毂电机标杆产品。对标国际一流产品,提出采用机、电、热、磁多物理域联合设计的方法应用于直驱轮毂电机的设计,结合拼块铁心工艺、一体注塑混合绝缘骨架技术、精密排绕线技术、高导热灌封胶及一体化灌封工艺、轻量化结构等先进制造工艺技术研制了一款高性能直驱轮毂电机。该电机的转矩密度和功率密度分别达到了21.3 N·m/kg和2.2 kW/kg,基本接近国际一流水平,验证了所提方法及相关技术的有效性。     

Vulnerable objects detection for autonomous driving: A review

Object detection performed by Autonomous Vehicles (AV)s is a crucial operation that comes ahead of various autonomous driving tasks, such as object tracking, trajectories estimation, and collision avoidance. Dynamic road elements (pedestrians, cyclists, vehicles) impose a greater challenge due to their continuously changing location and behaviour. This paper presents a comprehensive review of the state-of-the-art object detection technologies focusing on both the sensory systems and algorithms used. It begins with a brief introduction on the autonomous driving operations and challenges. Then, different sensory systems employed on existing AVs are elaborated while illustrating their advantages, limitations and applications. Also, sensory systems employed by different research are reviewed. Moreover, due to the significant role Deep Neural Networks (DNN)s are playing in object detection tasks, different DNN-based networks are also highlighted. Afterwards, previous research on dynamic objects detection performed by AVs are reviewed in tabular forms. Finally, a conclusion summarizes the outcomes of the review and suggests future work towards the development of vehicles with higher automation levels.     

一款48 V BSG电机控制器开发与验证

针对轻型混合动力汽车开发了一款48 V带传动一体化起/发电机(BSG)电机控制器。阐述了该控制器的总体设计方案,对BSG电机控制器的结构、硬件、软件进行了分析,提出了基于功率MOSFET模块的风冷电机控制器设计方案,并对风冷散热板进行了热仿真,研究了MOSFET模块散热效果。最后,对试验样机进行了台架测试,由测试结果可以看出,所设计48 V BSG电机控制器具有良好的控制效果。     

“中国风”首饰的设计思维与设计重构

在我国现代首饰设计中,对设计元素的选取和首饰语义的表述需要深入的品味和领悟传统文化,通过首饰的具体形态、材质、色彩和工艺来表现传统元素的内涵,展现"中国风"的魅力。以中国传统文化为载体,以民族符号和图案为具体形式,考究和推敲中华文明的精髓,挖掘和提升"中国风"的品味。用现代人的审美习惯和思维方式去重新凝练设计的元素,用现代首饰的制作工艺和现代首饰的设计语言去重构首饰产品的具体设计方案。通过抽象概括和创造性的思维方式,笔者运用"鼎"为元素设计了具有"中国风"特征的首饰作品,旨在丰富首饰设计的思维方式和首饰产品的文化内涵,在发扬和秉承传统文化的同时增加首饰产品的人文个性和文化附加值。     

移动在线实时绘制技术研究综述

移动在线实时绘制技术受移动互联网发展的驱动,为3维可视化、计算机视觉、虚拟现实、增强现实、扩展现实和元宇宙等新兴研究领域提供了核心技术的支撑。本文以在线实时绘制技术为切入点,探讨了该技术在移动端、Web端、云端和多端协同这4类平台下的发展重心和研究现状,并深度阐述了工业级在线云平台的实施方案。首先,针对移动端的在线实时绘制,分析了近年来移动端绘制硬件构架设计的优化方向;探讨了在功耗和带宽受到制约的情况下移动端如何对渲染算法进行加速,如何对高功耗的光线跟踪算法进行优化;列举了包括图形应用程序编程接口(application programming interface,API)和游戏引擎在内的移动端渲染工具。然后,针对Web端在线实时绘制,分析了Web端的3D渲染机制,梳理了以3D场景的轻量化预处理、大规模3D场景的细粒度化网络传输、3D场景的对等传输以及Web3D在线特效渲染为代表的Web端在线绘制的关键技术(尤其面向大规模3D场景),列举了国内外知名Web3D引擎并探讨了主流游戏引擎对Web3D应用的支持。再后,针对云端在线实时绘制,从应用托管、资源调度和串流这三大云平台的核心功能入手,调研了以串流应用优化技术为核心的在线云绘制现状。此后,从多端绘制任务分摊机制入手,分析了以“端云”协同和“端边云”协同为目标的在线多端协同绘制的发展。最后,以当前工业级在线云绘制平台为研究对象,分析了包括微软、英伟达、Unity、酷家乐等一线云绘制企业的在线实时云绘制平台方案,验证了移动在线绘制技术在工业界的实用性。     

校企合作计算机通信网的课程建设

针对相关通信企业的实际需求,从理论、实训、顶岗实习等几个方面论述了在校企合作模式下计算机通信网课程的建设思路。     

The simulation and analysis of leakage and explosion at a renewable hydrogen refuelling station

The number of hydrogen refuelling stations (HRSs) is steadily growing worldwide. In China, the first renewable hydrogen refuelling station has been built in Dalian for nearly 3 years. FLACS software based on computational fluid dynamics approach is used in this paper for simulation and analysis on the leakage and explosion of hydrogen storage system in this renewable hydrogen refuelling station. The effects of wind speed, leakage direction and wind direction on the consequences of the accident are analyzed. The harmful area, lethal area, the farthest harmful distance and the longest lethal distance in explosion accident of different accident scenarios are calculated. Harmful areas after explosion of different equipments in hydrogen storage system are compared. The results show that leakage accident of the 90 MPa hydrogen storage tank cause the greatest harm in hydrogen explosion. The farthest harmful distance caused by explosion is 35.7 m and the farthest lethal distance is 18.8 m in case of the same direction of wind and leakage. Moreover, it is recommended that the hydrogen tube trailer should not be parked in the hydrogen refuelling station when the amount of hydrogen is sufficient.     

制冷系统用分子筛干燥剂性能评价及标准化过程——行业标准《制冷系统用球形分子筛干燥剂》

分子筛是一种多孔晶形硅铝酸盐材料,因其独特的选择性吸附干燥性能,广泛应用于各类制冷剂的干燥净化.本文详细介绍制冷系统用分子筛干燥剂标准的国内、外发展情况,并对2012年7月新发行的标准《制冷系统用球形分子筛》进行了介绍,包括主要技术性能和检验方法,可以帮助制冷行业标准应用者正确运用标准,以达到预期目的.     

碳化硅控制器用膜电容器设计与测试

针对一款碳化硅控制器用膜电容器,采用有限元热仿真分析和台架测试相结合的方法研究其内部温度分布情况。设计了膜电容器内部结构,介绍了该膜电容器在碳化硅控制器内部的结构布置情况,建立了膜电容器的热仿真模型,重点研究了膜电容器在碳化硅控制器额定工况下的温度分布规律。制作膜电容器样品并在其内部埋设热电偶,对该膜电容器在额定工况下的实际温度进行了台架测试验证。通过仿真和测试结果的对比分析,证明了采用有限元热仿真研究碳化硅控制器用膜电容器的有效性。研究结果对于碳化硅控制器用膜电容器的高效散热设计具有一定的参考价值。