Dynamics of the railway track and the underlying soil: the boundary-element solution, theoretical results and their experimental verification

A combined finite-element boundary-element method is presented in detail to calculate the dynamic interaction of the railway track and the underlying soil. A number of results are shown for ballasted and slab track, demonstrating the influence of the stiffness of the soil and the rail pads on the vertical compliance of the track. The compliance of the track is combined with a simple model of the vehicle giving the transfer function of vehicle-track interaction. An experimental verification of the theoretical results is achieved by harmonic and impulse excitation with and without static (train-) load and by combined measurements of train-track-soil interaction. A clear vehicle-track resonance is found for the slab track with elastic rail pads and for higher frequencies at highspeed traffic, the dynamic axle loads due to sleeper passage are reduced.     

试验监理在国际招标工程中的作用

在国际招标工程中,工程试验是一项十分重要的工作,通过工程试验对国际招标项目的经济效益进行控制分析,能指导工程实际,改进施工方法,确保工程质量。     

装配式梁桥横向协同工作性能度量指标的研究

为了表征运营期间装配式梁桥的横向协同工作性能,提出了一种间接度量指标——相邻预制梁间的应变相关系数;同时建立了装配式梁桥的简化力学模型,通过推导建立了该指标的解析表达式。理论分析和数值仿真研究表明,在保证足够的样本长度条件下,交通流荷载趋向统计稳定,此时结构特性成为该度量指标的唯一影响因素,证明了该指标具备表征装配式梁桥横向协同工作性能的条件。     

Exact and simplified estimations for elastic buckling pressures of structural pipe-in-pipe cross sections under external hydrostatic pressure

Structural pipe-in-pipe cross sections have significant potential for application in offshore oil and gas production systems because they combine thermal insulation performance with structural strength and self weight in an integrated way. Such cross sections comprise inner and outer thin-walled pipes with the annulus between them fully filled by a selectable filler material to impart an appropriate combination of properties. Structural pipe-in-pipe cross sections can exhibit several different collapse mechanisms, and the basis of the preferential occurrence of one over the others is of interest. This article presents an exact analysis for predicting the elastic buckling behaviours of a structural pipe-in-pipe cross section when subjected to external hydrostatic pressure. Simplified approximations are also investigated for elastic buckling pressure and mode when the outer pipe and its contact with the filler material is considered as a pipe on an elastic foundation. Results are presented to show the variation of elastic buckling pressure with the relative elastic modulus of the filler and pipe materials, the filler thickness, and the thicknesses of the inner and outer pipes. Case studies based on realistic application scenarios are used to show that the simplified approximations are sufficiently accurate for practical structural design purposes.     

船用液货控制系统设计

介绍了一种液货船的计算机集成控制系统架构。该架构将液货船液货系统和压载控制纳入统一的智能化管理平台中,实现了液货船的高度智能化。     

一种用m序列产生有限域GF(2m)上元素矢量表的算法

有限域理论在伪随机序列设计中有着非常广泛的应用。有限域上函数（如迹函数）的加、减运算需要用到域上元素的矢量形式。给出有限域的一些特性和运算法则并提出一种利用m序列产生有限域GF（2^m）上所有元素矢量形式的算法。该算法避免使用长除法，可以加快域上元素矢量表的生成速度，编程实现也很简单。     

使用新型辅助变流器节能

新型辅助变流器(BNU)及其新结构设计可减轻有轨车辆辅助电源装置的质量.与传统的典型地铁车辆的辅助变流器相比,这种新辅助变流器的质量可减轻约50%,并且可大大降低能耗.通过采用中频隔离变压器和非焊接箱体可减轻质量,随之而来也扩展了BNU的功能.     

TDJK-DS203电动锁闭可控减速顶的改进设计

针对TDJK-DS203电动锁闭可控减速顶在使用中出现的问题，进行性能改进，增强锁闭可靠性，简化电控阀零部件，减少电控阀故障点，使其达到安全可靠的锁闭效果。改进后的电动锁闭可控减速顶定型为TDJK-DS203A。     

南通港南通港区规划中若干问题的探讨

由于南通地区公路客运优势的确立,南通港区作为南通市对外交通的中心地位受到严重挑战,因此,港区功能由客运转为货运成为必然。对客运设施进行全面改造;将浮码头改造为固定码头;对任港河口的封堵进行研究;废弃内河港池,扩大陆域纵深及面积是南通港区改造的四大关键举措。     

锰冶炼男工肝功能的调查研究

为探讨锰对冶炼工人肝功能的影响，对某厂70名冶炼男工和24名对照男工的主观症状和血清总蛋白、白蛋白、谷丙转氨酶、谷草转氨酶、胆碱酯酶活性和麝香草酚浊度进行了调查，结果显示，作业环境空气中MnO2几何均数为0．65mg/m^3，两组工人的自觉症状主拆率未风显著性差异，上述肝功能指标的均值和异常率比较也无显著性差异。