铁路突发事件应急资源调配问题分析

快速有效的救援是减少铁路突发事件损失的重要工作。为降低突发事件所造成的损失,要求决策者能够快速做出资源调配方案。建立多出救点、多资源的基于时间最短和成本最低的多目标规划模型。通过数学描述给出解析算法,并通过具体算例验证模型的正确性和算法的有效性。     

混杂纤维片材拉伸性能研究

参考标准GB/T3354-1999测试了由碳纤维、玻璃纤维和尼龙纤维等编织的不同混杂纤维布和增强环氧树脂复合板的拉伸强度、弹性模量和拉伸过程曲线等,分析了混杂比例对干纤维布和纤维增强环氧树脂板拉伸性能的影响。结果表明:与1C1G和2C1G纤维布相比,1C2G单向纤维布呈现出更为理想的分级破坏形式,应力传递更稳定;在碳、玻璃混杂纤维增强环氧树脂板体系中,1C2G复合板延性优越,最大延伸率达1.68%;与碳、玻璃混杂纤维增强环氧树脂板相比,含有尼龙纤维的混杂纤维树脂板在拉伸过程中具有下降段,延性效果改善良好,但抗拉强度偏低;环氧树脂在复合材料中进行应力传递和重分配,有效提高了复合材料的整体受力性能。     

客运专线铁路混凝土岔枕生产技术研究

由于客运专线岔枕承载力大、外形尺寸要求高,因此对混凝土的强度及耐久性、预应力钢丝的丝位及张拉时的均匀性都提出了很高的要求。简要比较了客运专线混凝土岔枕采用机组流水法和长线法生产的两种技术特点;为解决长线法生产岔枕时由于混凝土坍落度较大、混凝土早期强度增长慢、生产周期长的问题,介绍所研制新型混凝土材料的优点。实践证明:采用长线法生产客运专线岔枕,同时使用自主研发的混凝土新材料,既保证了产品的质量,又使岔枕的生产周期不受影响,有利于客运专线岔枕的推广使用。     

机械产品信息管理系统的开发和应用

根据机械产品具有层次性和特定隶属关系的特点,研究建立数学模型和适应计算机管理的数据结构,阐明系统开发的原理与过程,提出用产品树实现对机械产品信息的层次化管理,实现了产品信息的有效组织和利用,对新产品开发和既有产品管理都有积极的作用.     

TCP缓释陶瓷材料的研究

以无定型磷酸三钙为基体,通过加入微量元素Cu,制备出具有缓释作用的陶瓷材料．通过水浸实验和XRD研究了缓释陶瓷的金属离子Cu释放速度以及陶瓷材料的微观结构．     

按道路使用性能选择沥青混合料

通过对沥青路面的高温车辙,低温缩裂和疲劳寿命的计算分析,得出了沥青路面三层各自的主要功能,提出按照各层所承担的主要功能选择合适的沥青混合料。     

轨道交通新型高分子材料研发及应用进展

综述了我国几种新型高分子材料的研究现状,分析了典型材料的功能特性和技术关键点,介绍了现有技术在轨道交通领域的应用情况,并指出了我国轨道交通高分子材料的研究方向。     

Time-dependent fuzzy random location-scheduling programming for hazardous materials transportation

The tremendous use of hazardous materials has promoted the economic development, which also brings about a growing risk causing a widespread concern. In this work, we consider a location-scheduling problem on hazardous materials transportation under the assumption that transportation risks are time-dependent fuzzy random variables. First, we formulate a scheduling optimization model and design a fuzzy random simulation based genetic algorithm to optimize the departure time and dwell times for each depot–customer pair. Then we establish an expected value model and design a modified particle swarm optimization algorithm to minimize the en route risks and site risks. Finally, numerical examples are given to illustrate the effectiveness of the proposed models and algorithms.     

Size effect on residual stress in low transformation temperature welded joints

It has been reported that low transformation temperature (LTT) weld metals are beneficial to generation of compressive residual stress around weld zone. In this study, the relationship among residual stress, size effect of LTT welded joints with different plate width and thickness as well as martensite start (Ms) temperatures was investigated by experimental and finite-element analysis. It was found that heat dissipation and thermal expansion coefficient of LTT weld metal had a significant impact on residual stress. Welded joint with a small plate width led to greater compressive residual stresses in the LTT weld, which was due to the lower heat dissipation and smaller thermal expansion coefficient of the LTT weld metal in due course of cooling process. Additionally, the finite-element analysis revealed that increasing plate width mainly affected the longitudinal residual stress, while increasing the plate thickness influenced all the residual stress components in the LTT weld. Furthermore, the LTT weld with a lower Ms temperature of 191 °C resulted in greater compressive residual stresses, and was less sensitive to the LTT joint size, as against the Ms temperature of 398 °C.     

国内外汽车材料多环芳烃管控现状及趋势

随着汽车产业的不断快速发展,人类健康和环境安全越来越受到重视。多环芳烃是一类致癌物质,部分发达国家和地区早就对汽车材料中的多环芳烃进行管控。作为我国汽车行业禁用物质管控标准,GB 30512《道路车辆禁用物质要求》将多环芳烃纳入管控范围。文章系统地梳理了国内外汽车材料多环芳烃的检测与管控要求,从前处理提取、净化方式和检测设备进行检测方法的对比分析,以及对国内外标准关于PAHs管控物质种类与限值要求进行了对比。国内外汽车材料PAHs管控现状的整体汇总对GB 30512标准修订中PAHs的管控要求提供了参考。