山区高等级公路沥青路面病害浅析

结合我省山区高等级公路沥青路面建设质量检测中发现的问题,对沥青路面病害的成因进行了分析,并提出了相应的质量控制措施。     

穿越名木古树群浅埋隧道施工技术

介绍了杭州解放路～新安江连线工程解放路隧道采用浅埋暗挖法穿越名木古树群的施工技术,对今后类似工程有一定的借鉴作用。     

灰色关联分析的铁路客运服务水平评价体系研究

随着客运市场竞争日益增加,铁路客运服务面临着严重的压力.从运输产品、运输过程、联合运输、服务形象4个方面分析影响铁路客运服务水平的因素.建立评价体系,利用灰色关联分析方法,结合交通调查数据进行实例的应用分析.     

青藏铁路TCDS实时数据接入方案的研究与实现

介绍青藏铁路客车运行安全监控系统(TCDS)实时数据接入系统的结构设计和工作流程.该系统采用移动GSM公网和GSM-R相结合的方式,保证青藏车运行过程实时监测数据的连续传输.     

角色访问控制在青藏铁路电务管理系统中的应用

用户权限管理是青藏铁路电务信息系统设计中的重要环节,是电务部门安全运行的有力保证.简要介绍基于角色的权限管理,并提出一种通用动态用户权限管理方案及实现方法.     

Interdependencies between turning points in life and long-term mobility decisions

Turning points in life include important personal and familial events as well as changes in the places of residence, education and employment. The latter usually involve alterations in the spatial distribution of activities and, hence, in the activity space, thereby also influencing the daily travel behavior. In this context, the ownership of mobility tools, such as cars and different public transport season tickets, also plays an important role, since people commit themselves to particular travel behaviors as they trade large one-time costs for a low marginal cost at the time of usage. At the same time, decisions concerning mobility tool ownership have lasting effects, as have the decisions concerning location choices. A longitudinal perspective on the dynamics of these long-term mobility decisions is available from people??s life courses, which link different dimensions of life together. In order to study these dynamics and the influence of turning points in life, a longitudinal survey covering the 20?year period from 1985 to 2004 was carried out at the beginning of 2005 in a stratified sample of municipalities in the Zurich region, Switzerland. The paper describes the data collection and then presents results which show that there exist strong interdependencies between the various turning points and long-term mobility decisions during the life course, as events occur to a great extent simultaneously. Persons tend to aim for compensation between the different dimensions of life.     

Convergence of different wake alignment methods in a panel code for steady-state flows

Wake alignment models are always included in the modern panel codes for marine propeller analysis. The wake alignment algorithms influence directly the rate of convergence and the accuracy of calculations. In the present work, firstly, four different numerical methods to implement the wake alignment algorithms for the steady calculation are described. They perform quite differently in terms of convergence history and convergence rate. The comparison with the other methods shows that the direct application of the unsteady method leads to a much slower convergence rate. Secondly, high-order numerical methods including second-order and fourth-order Runge–Kutta methods are introduced into the wake alignment, which results in high-order wake alignment algorithms. The analysis of the results shows that the high-order methods generate a different wake geometry from the low-order method. The thrust coefficient and torque coefficient have also been compared.     

一种新型电力电子变压器CHBR直流电压平衡控制策略

以无工频变压器新型电力机车牵引传动系统电力电子变压器(power electronic transformer, PET)级联H桥整流器(cas鄄caded H-bridge rectifier,CHBR)为研究对象;建立电力电子变压器CHBR数学模型;以瞬时功率理论为基础,提出一种新型电力电子变压器CHBR直流电容电压平衡控制控制策略;同时实现非理想牵引网电压下系统单位功率因素运行。最后通过Matlab/Simulink计算机仿真软件,仿真结果表明所提控制策略的有效性和优越性。     

Post-Car World: data collection methods and response behavior in a multi-stage travel survey

Transportation - The main research question addressed by this study is to what degree individuals would change travel modes, time allocation and activity patterns after experiencing large changes...     

Analyzing the dispersion of cargo vapors around a ship’s superstructure by means of wind tunnel experiments

In a previous study, it was found that cargo tank operations like cleaning and venting, lead to higher cargo vapor concentrations around the ship’s superstructure. Can wind tunnel experiments confirm these findings? Is there an improvement when using higher outlets at high velocities compared to lower outlets with a low outlet velocity? Is there a relation between relative wind speed and measured concentration? These questions were investigated in the Peutz wind tunnel. By using a tracer gas for the wind tunnel experiments, concentration coefficients have been calculated for various settings. The study shows that using high-velocity outlets is an efficient way to keep concentrations as low as possible. The only exception is for relative wind directions from the bow. In this last case using a manhole as ventilation outlet leads to lower concentrations. With increasing wind speeds the building downwash effect resulted in higher concentration coefficients near the main deck. This study confirms our on-board measurements and suggests the lowering of the ventilation inlet of the accommodation, so that the high-velocity outlet can be used safely at all times.