城市空间与其使用价值——汕头中山公园的城市空间意义

文章通过论述汕头中山公园在策划背景、分析论证、用地选址和大规模建设各方面，是如何作为城市空间来体现其社会使用价值，来探讨城市空间产生过程中错综复杂的政治、经济、社会和文化多方面力量的博弈，以及城市社会和空间使用的相互关系。     

关于信息化测绘时代工程测量发展的思考

如今我国信息化技术全面发展，尤其对于工程测量工作领域来讲，不管是在工程建设和管理方面都产生不小的支撑引导效用。由此，笔者具体结合如今工程建设信息化测绘核心任何以及设备布置细节，进行结构整体安全管理周期和周边地理空间信息技术发展能效整理解析，试图将工程测量最新发展机遇和技术挑战问题处理完全。希望能够借此为日后一定时期范围内相关工程测量规划主体提供合理指导性建议内容，最终为我国各类工程事业可持续发展前景绽放奠定深刻适应基础。     

一种计算空间异面高压线间最短距离的方法

在电力工程建设、运行、管理中,需要遵循许多行业规范,尤其是高压线间的间距,关系到电网运行的安全与否。对于一些容易判断两线间最短距离的高压线,如平行的高压线等,可以方便的求出其最短距离,但是,在遇到一些不易判断出两线间最短距离位置的高压线时,需要通过一定的方法求出两高压线间的最短距离,以判断是否符合规范要求,确保电网的安全运行。本文提出一种利用Mathematica软件计算空间异面高压线间最短距离的方法。     

Electrical Breakdown Properties and Space Charge Formation in High Temperature Region in Ultraviolet Ray Irradiated PVC

Polyvinyl chloride (PVC) is the most popular insulating material for electric wiring instruments. However, an exothermic reaction above 150 °C may cause deterioration of the insulating properties of PVC. Therefore, it is important to clarify the heat degradation in PVC, not only to investigate the ignition of electrical wiring products but also to use electrical products safely. It is known that ultraviolet (UV) irradiation causes chemical deterioration of PVC and an increase in its conductivity. Generally, it has been thought that the electrical breakdown properties, electrical conduction, and insulating performance are affected by space charge accumulation in an insulating material. A high temperature pulsed electroacoustic (PEA) system usable up to 250 °C has been developed, and the PEA system can measure the space charge distribution and conduction current in the high temperature range simultaneously. In this investigation, the space charge distribution and conduction current were measured up to electrical breakdown in a non‐UV irradiated sample (normal PVC) and in 353 nm and 253 nm UV‐irradiated PVC samples in the range from room temperature to 200 °C in a DC electric field. In the short wavelength UV irradiated PVC sample (253 nm, 300 h), a deterioration of breakdown strength at 90 °C to 150 °C and negative packet‐like charges were observed at 60 °C and 100 °C, a positive charge accumulated in front of both the anode and cathode above 90 °C, and a higher electric field near the cathode side because the positive charge of the cathode side was greater.     

Data-driven placemaking: Public space canopy design through multi-objective optimisation considering shading,structural and social performance

In the context of ongoing densification of cities and aging urban populations, public spaces are a crucial infrastructure to support the physical and mental wellbeing of urban residents. The design of public space furniture elements is often standardised, and not considered in relation to environmental conditions and mechanisms of social interaction. This article presents a digital workflow to generate site-specific designs for shaded public seating, considering the relationships of local public places to their surroundings. A strategy for customised and site-specific design is developed through the use of multiple software tools, employing evolutionary algorithms and multi-objective optimisation. The method is applied to a small public space canopy prototype installed within a public housing estate in Hong Kong, incorporating additional criteria to achieve a low-cost and light-weight structure. Through multiple stages of refinement and optimisation, a material, structural and social performance-driven outcome was achieved that creates a shaded space for public seating, people watching and social interaction. As part of a larger research agenda exploring architectural form-finding and environmental psychology, the project represents potential new applications in the emerging field of socially driven computational design.     

受限空间安全作业管理浅析

受限空间因受作业场所限制,存在的危险因素较多,受限空间安全管理控制措施为:建立许可制,落实责任和措施,做好受限空间作业人员的个体防护,对受限空间作业的安全管理要实行从审批到应急处理全过程的控制。介绍了受限空间的危险特点和事故类型,提出了受限空间作业安全管理的具体措施。     

Stress distribution in thick-walled cylinder due to non-uniform radial pressure on the example of reinforcement corrosion in concrete

This paper presents an analytical solution to the non-uniform pressure on thick-walled cylinder. The formulation is based on the linear elasticity theory (plain strain) and stress function method. As an example, the proposed solution is used to model the stress distribution due to non-uniform steel reinforcement corrosion in concrete. The model is formulated considering different scenarios of corrosion pressure distribution. It is validated against the finite element model for different cases of non-uniform pressure distributions. The results show that the corrosion-induced cracks are likely to start just beyond the anodic zone. This is confirmed by the experimental tests on concrete cylinder exposed to non-uniform accelerated corrosion of steel reinforcement. The model can be effectively used to calculate the distribution of corrosion-induced stresses in concrete.     

钛表面激光熔覆NiCr-Ag复合涂层结构及空间摩擦学性能研究

利用激光熔覆技术在钛基材表面制备了NiCr-Ag复合涂层。用XRD、SEM和HRTEM分析了涂层的组成和组织结构,利用空间摩擦学系统对复合涂层在三种模拟空间环境(高真空、原子氧和紫外辐照)以及大气环境下的摩擦磨损性能进行了系统的研究。采用SEM和EDS对磨损后复合涂层和对偶钢球的形貌和元素面分布进行了分析,揭示了复合涂层在模拟空间环境及大气环境下摩擦磨损失效机理。结果表明：复合涂层在大气环境条件下的摩擦磨损性能优于在三种模拟空间环境下的摩擦磨损性能；真空下的辐照对复合涂层的摩擦磨损性能有显著的影响,辐照会增加涂层表面氧化；复合涂层在高真空、原子氧和紫外辐照模拟空间环境下的磨损机理为较严重的粘着磨损、磨粒磨损和塑性变形,在大气环境条件下的磨损机理主要为磨粒磨损。     

码垛机器人运动学分析及关节空间轨迹规划研究

以IRB-460工业机器人为研究对象,针对其运动学建模及在笛卡尔空间和关节空间下的轨迹规划方法展开研究并进行对比。对机器人本体进行了机器人运动学分析,利用多项式轨迹插值算法进行了关键点间的轨迹规划,完成了重叠型码垛的作业流程。利用Robotics Toolbox完成了轨迹规划算法仿真,并进行了结果分析。仿真结果表明在关节空间下进行轨迹插补所得的路径点更为优化,所得的轨迹更为满足作业任务,具备合理性。     

Polyaniline sensitized Pt@TiO2 for visible-light-driven H2 generation

Polyaniline is a typical conducting polymer with high migration electron rate, good stability, eco-friendly properties, and high absorption coefficients for visible light. In the present study, polyaniline decorated Pt@TiO₂ for visible light-driven H₂ generation is reported for the first time. The above-mentioned nanocomposite is prepared through a simple oxidative-polymerization and characterized by infrared spectroscopy, transmission electron microscopy, X–ray diffraction, thermogravimetric analysis, and ultraviolet–visible diffuse reflectance spectra. Polyaniline modification improves the absorption of the nanocomposite in visible light region via a photosensitization effect similar to dye–sensitization but does not influence the crystal structure and size of Pt@TiO₂. The polyaniline modified Pt@TiO₂ exhibits a remarkable visible light activity (61.8 μmol h⁻¹ g⁻¹) and good stability for H₂ generation (with an average apparent quantum yield of 10.1%) with thioglycolic acid as an electron donor. This work provides new insights into using conducting polymers, including polyaniline, as a sensitizer to modify Pt@TiO₂ for visible-light hydrogen generation.