一种新的基于行车道路网数据模型及应用

根据交通管理的需求,选择行车道作为道路网络的最小建模单元,提出了一种新的基于行车道交通路网模型。模型利用几何和逻辑这两种网络结构,实现了道路网络几何特征表达和拓扑连通关系的分离;利用两层路网结构实现道路网络的多尺度表达;最后应用该模型讨论了移动对象的时空管理并以实例对模型进行了验证。     

HXN5型内燃机车空气管路系统

随着我国铁路运输事业向着高速、重载的方向迅速发展．对铁路列车制动技术提出了更高的要求。HXN5型内燃机车是戚墅堰机车有限公司与美国通用电器公司共同合作的,对HXN5型内燃机车空气管路系统的掌握和了解对机车的运用及检修均有很大的帮助。     

狮岭高架桥改建结构选型及设计探讨

针对狮岭高架桥扩建期间不能中断交通的要求,综合考虑施工阶段交通流的转换、施工工艺、原路基利用率、工程造价等因素的影响,通过方案比选,确定最优的上、下构方案。     

带有阻尼项的三维欧拉方程组球对称解

研究了一类带有阻尼项的三维等熵可压缩欧拉方程组经典解局部存在性和弱解的整体存在性。一方面利用对称双曲型方程组解的存在性结论,将该方程组转化为对称双曲型方程组,得到了经典解的局部存在性;另一方面由新坐标的引入,该方程组转化为比较熟悉的p-系统,并通过Glimm格式证明了它的整体弱解的存在性。     

Evolving mechanism of eutectic carbide in as-cast AISI M2 high-speed steel at elevated temperature

AbstractThe evolution in type,size and shape of carbides in as-cast American Iron and Steel Institute(AISI) M2 high-speed steel before and after annealing were investigated.The micromechanism which was responsible for those changes was also analyzed and discussed.At the initial stage of reheating,metastable M2C-type carbide decomposed continuously.M6C-type carbide nucleated at the interface of M2C/γfirstly and grow from surface to center.Then MC-type carbide nucleated at both surface of M6C/M6C and inner of M6C.With the increasing decomposition of the metastable M2C-type carbide,the rod-shaped construction of eutectic carbide began necking,fracturing and spheroidizing gradually.Held enough time or reheated at higher temperature,particle-shaped product aggregated and grew up apparently,while secondary carbide precipitated in cell and grew up less sig- nificantly than the former.Based on the above microstructural observation,the thermodynamic mechanism for decomposition of M2C carbide,for spheroidization of products,and for the growth of particles were analyzed.The rate equations of carbides evolution were derived,too.It shows that the evolving rate is controlled by diffusion coefficients of alloy atoms,morphology of eutectic carbides and heating temperature.     

Research on electron beam welding of in situ TiB<Subscript>2p</Subscript>/ZL101 composite

Electron beam welding of in situ TiB_2p reinforced aluminum composites was studied. The results show that no obvious pores or cracks is presented in the weld seam. The grains in the weld seam are remarkably refined and TiB₂ particles distribute much more homogeneously than that in base metal. The hardness values of fusion zone and heat affected zone (HAZ) are both increased in comparison with that of base metal. There are no interface reactions between TiB₂ particle and Al matrix. This results supply the evidence that the novel TiB_2p reinforced aluminum composites can be well joined with the electron beam welding.     

六速双离合器自动变速器开发

简述了某六速双离合器自动变速器的机械传动系统结构,给出了该变速器最佳动力性换挡策略,并进行了NVH仿真分析.对所开发的液压阀体总成进行的试验表明,该阀体总成的挡位平均响应时间为30.6 ms,比目前国外同类样品响应时间快.介绍了所开发的湿式双离合器结构并进行了双离合器总成试验.结果表明,双离合器1可进行精确地换挡控制;双离合器2虽然能进行换挡,但不易进行精确控制.     

施工企业成本管理之我见

建筑行业门槛低,市场竞争激烈,利润不断摊薄。施工企业面临严竣经营形势,唯有强化成本管理,增收节支,才能在经营活动中有所收获。该文通过对建筑公司在企业及项目部两级成本管理方面的制度、规则及策略进行分析,总结了施工企业在市场经济条件下成本管理方面的部分经验,对施工企业提高市场竞争力和经济效益将有一定的借鉴作用。     

临沂市沂河大桥设计

本文对沂河大桥的设计作了简要介绍并对刚架拱桥、钢管混凝土系杆拱桥的设计与施工要点进行了浅述。     

提速道岔运用中存在的问题分析及措施

对提速道岔在济南电务段管修区段运用3年来存在的问题及原因进行了分析，提出了解决问题的相关措施和建议。