材料超塑性和超塑成形/扩散连接技术及应用

大量的工程材料都具有超塑性,以材料超塑性为理论基础的超塑成形/扩散连接技术是先进制造技术的一种,在航空航天等许多工业部门得到了越来越多的应用.分析了材料超塑性现象,超塑性变形机理研究进展,超塑成形/扩散连接技术的理论基础.以及超塑成形/扩散连接复合工艺的技术优势、研究进展和应用现状,并展望了超塑成形/扩散连接技术的发展趋势.     

精密成形技术在航天领域的应用进展

介绍了精密成形技术中最具代表性的超塑成形、强力旋压、等温锻造、热等静压粉末冶金与激光快速成形等精密成形技术在航天领域中的应用情况.指出了国内外精密成形技术发展差距,并对精密成形技术的发展趋势进行了展望.     

OTN技术在轨道交通中的应用

为确保城市轨道交通(轻轨、地铁等)运行的稳定性、高效性,OTN网已经在城市轨道交通的通信中发挥重要作用,将对OTN技术在轨道交通中的几种实际应用进行分析与阐述。     

蒸发冷却技术在轨道交通领域的应用形式探讨

介绍了蒸发冷却空调技术在轨道交通领域的三种应用形式,并通过测试数据论述该技术在解决目前国内地铁工程中存在的地铁高架站候车区环境舒适性差、冷却塔布置困难等问题中发挥的重要作用.     

超塑处理对喷射成形GCr15钢超塑性的影响

研究了超塑处理对喷射成形GCr15钢超塑性的影响，超塑性拉实验结果表明，未经超塑处理的铸态试样，延伸率为119％，经过二次油淬和二次油淬＋高温回火超塑处理的两种试样，延伸率分别为328％和671％，变形温度和应变速率对GCr15钢的超塑性有一定的影响，但材料的微观组织对其超塑性具有决定性作用，超塑处理改变了材料试样的微观组织，导致其超塑性发生变化，经过二次油淬＋高温回火超塑处理后试样具有球化组织，其超塑性最好，未经超塑处理的铸态试样具有珠光体组织，超塑性最差，经过二次油淬超塑处理后试样的组织是马氏体和少量碳体物的混合，其超塑性介于上述两种试样之间，喷射成形工艺使GCr15钢获得均匀细化的稳定组织，这对于细晶超塑性是必要的，超塑处理材料的超塑性得到更大的提高。     

快速成形技术在陶瓷领域中的应用

简要介绍了比较成熟的几种快速成形方法。着重介绍了快速成形技术在陶瓷领域中的应用，讨论了技术生产陶瓷件存在的问题及发展方向。     

超声波振动条件下磁控溅射纳米材料的超塑变形研究

根据高性能纳米材料高精度成形的发展需求,介绍了磁控溅射纳米材料的组织及力学特性,分析了磁控溅射纳米材料超塑成形的优缺点,描述了大功率超声波振动对超塑成形的促进作用。综述了国内外超声波辅助塑性成形的发展现状及最新研究进展,提出了超声波振动辅助超塑成形的发展趋势。     

软交换技术在轨道交通通信系统中的应用

经济的快速发展使得人们的生活节奏不断加快,而更多的人口为了获得更好的生活都涌入到城市中,大量的人口使得城市的交通不堪重负,为了更好地帮助城市居民出行,通过建设城市地铁交通网络,能够为民众的出行提供极大的便利。地铁作为现代城市发展中的重要组成部分在城市交通体系中占据着重要的地位,轨道交通通信系统是地铁建设中的重要一环,仍然有许多的技术问题需要解决,通过将软交换技术应用于轨道交通通信系统中将有助于轨道交通通信系统性能的提升。本文将在简要介绍软交换技术的基础上对软交换技术在轨道交通通信系统中的应用进行分析阐述。     

军工领域金属粉末注射成形的工艺研究与应用

介绍了金属粉末注射成形工艺的应用,制备工艺的现状与发展,特别介绍了这项工艺在枪械零件等相关领域的开发与应用。通过对工艺流程的解析,介绍了国外同行生产的同类产品和国内产品的应用。通过应用实例,介绍了国产金属材料采用蜡基材料的可行性,以及采用国内工艺装备实现的工艺过程。     

TC4深筒形件超塑预成形模具型面设计及变摩擦厚度控制

以正反向超塑成形厚度均匀的TC4钛合金深筒形件为背景(厚度精度要求1.6mm±0.2mm),设计了多种预成形模形状,采用MSC.MARC有限元模拟研究了不同形状的预成形模对深筒形件侧壁厚度分布的影响, 并分析了预成形模和终成形模的表面摩擦系数分别对成形件壁厚分布的影响,提出了模具型面变摩擦控制厚度分布的方法.结果表明:预成形模对压边部分环形带区域和筒形件底部区域的局部预减薄,对最终侧壁的厚度分布有非常大的改善.同时,合理地增大预成形模的表面摩擦能显著增加预成形的局部减薄作用,对于提高工件最终壁厚分布均匀性有利.减小终成形模的摩擦,可以使板料整体变形均匀化,壁厚分布趋于均匀.根据有限元分析结果,对模具表面进行处理,并通过正反向超塑成形实验制得TC4钛合金深筒形件,其厚度分布满足1.6mm±0.2mm.     

5083铝合金壳体超塑胀形加载曲线优化控制

为了改善超塑成形零件的壁厚均匀性问题,优化了有限元软件MARC的加载算法.在每一步长中选取20个应变速率最大的单元,求平均值,并与最佳应变速率对比,获得优化加载曲线.基于有限元分析,选择5083铝合金壳体进行了超塑成形实验.研究结果表明:优化的加载算法使应变速率始终保持在最佳应变速率附近,提高了零件变形严重区域的厚度;避免了在加载过程中由于壁厚不均匀使得裂纹产生,验证了模拟结果的准确性.与MARC默认的加载算法相比,采用优化加载算法能改善零件的壁厚均匀性.     

Optimal rail container shipment planning problem in multimodal transportation

The optimal rail container shipment planning problem in multimodal transportation is studied in this article. The characteristics of the multi-period planning problem is presented and the problem is formulated as a large-scale 0-1 integer programming model, which maximizes the total profit generated by all freight bookings accepted in a multi-period planning horizon subject to the limited capacities. Two heuristic algorithms are proposed to obtain an approximate optimal solution of the problem. Finally, numerical experiments are conducted to demonstrate the proposed formulation and heuristic algorithms.     

离心式热泵机组的设计与应用

介绍了离心式热泵的分类和特点,并分别对低温、中温、高温离心式热泵的设计方案进行了概述,重点介绍了高温热泵的设计过程及应用实例.结合某实际工程案例,指出在应用离心式热泵制冷、供热时,具有节能、环保、运行费用低等众多突出优点.     

调整结构抓重点 节能环保是关键

本文根据国务院的《关于加快发展节能环保产业的意见》精神,结合我国包装行业的实际,详细地阐述了在当前我国经济放缓的形势下。包装行业应把发展节能环保产业作为调整结构的关键。     

我国交通运输行业物联网技术应用模式研究

应用物联网技术能有效提高交通运输领域的运行效能并促进行业转型,已被公认为解决我国当前严峻的交通运输诸多问题的首选措施。本文首先分析了物联网技术的优势及交通运输行业发展趋势,在此基础上,研究物联网与交通运输领域的结合之处并给出了交通运输物联网定义。针对传统的交通运输智能化发展过程中遇到的诸多问题,提出了未来交通物联网发展模式。该模式提出基于统一前端信息采集以实现真正的互联互通,它能极大节省技术推广成本、挖掘信息潜在价值,促进可持续的信息服务市场形成和行业升级。     

蒸发冷却空调应用中存在的问题及解决设想

目前,集中式蒸发冷却式空调系统在我国西部地区得到了越来越广泛的应用,但其缺点是风道大、使用灵活性差,而且不能实现多个房间分别进行调节控制。针对集中式系统的缺点,本文提出采用有别于传统风机盘管加新风系统的半集中式蒸发冷却空调系统,并从理论上进行了可行性分析。     

海水热泵机组工作原理及应用

海水热泵机组利用海水、污水等可再生能源,可实现冬天供热、夏天供冷,既节能又环保,满足区域性居民和商用建筑供暖和供冷的需求,发展潜力大.     

The Construction of a Green Transportation System of China

Since the 21st century, the transportation industry in China has achieved rapid growth with a significant increase in the transport capacity; however the development has also greatly impacted the energy saving & environmental conservation. This paper takes into account non-commercial vehicles such as private cars in the statistics of energy consumption and pollution of Chinese transportation system. This method extends on previous methods which solely include commercial vehicles in these statistics. Based on more comprehensive quantitative data, it reviews the progress in the energy saving and environmental conservation efforts by the Chinese transportation industry and points out that the rapid increase of energy consumption and pollution emission and the deterioration of traffic congestion are prominent problems in the development of the Chinese transport industry. The main reasons for theses problems include the unbalanced development of different transport modes, the irrational layout of integrated transport hubs, the inadequate law, regulations and standards, and the use of suboptimal technology. Based on these findings, this paper proposes several goals for the construction of a green transportation system in China including the establishment of a transportation management system, the improvement of transportation energy efficiency, the control of environmental pollution and the alleviating of urban traffic congestion. Additionally, it points out that in order to build a green transportation system in China, multiple aspects should be enhanced, i.e., the formulation of traffic planning, the optimization of transport structure, the development of urban public transport, improvement of integrated hubs, administration of energy saving and environmental conservation, development of intelligent transportation systems, technical innovations, etc..     

Measurement and analysis of truck and rail vibration levels in Thailand

Worldwide increase in trade, foreign direct investment, capital flows, migration and the spread of technology has caused an increased focus to be put on designing packages that can protect goods shipped globally. This requires a wide‐ranging understanding of the distribution environments on a global basis. Several past studies have mapped the vibration levels for surface transportation along the most popular shipment routes in countries such as Brazil, Canada, China, India and the USA. This study was conducted to provide a comprehensive understanding of the vibration levels observed for truck and rail shipments for major transportation routes in Thailand, one of the leading economies in the Southeast Asia region. Data recorders were used to collect the vibration data which were then analysed in terms of power spectral densities. Vibration levels observed from various segments of transportation are presented in the form of power density spectrums. Composite spectrums that can be used to simulate the measured vibration conditions in Thailand are presented. Copyright © 2010 John Wiley & Sons, Ltd.