面向实际交通状态的混合动力汽车能耗和CO2排放模型

由于混合动力汽车与传统燃油车的能耗排放因子具有差异性，导致机动车交通路网能耗排放的量化评估存在不确定性。本文建立混合动力汽车在实际交通状态中的能耗和CO2排放因子测算模型，基于车辆比功率VSP(Vehicle Specific Power)作为车辆行驶状态与能耗排放之间耦合关系的表征参数。通过引入内燃机转速区分内燃机开启和关闭工作状态，并计算内燃机开启状态下VSP对应的平均能耗率，同时，建立能够解析混合动力汽车能耗排放产生机理的VSP分布。通过收集典型行驶工况下车辆测试油耗数据和北京市车辆实际行驶轨迹数据，验证了模型的准确性，并应用模型测算混合动力汽车不同速度区间下的油耗和CO2排放因子。研究结果表明：在城市行驶工况(UDDS)和高速行驶工况(HWY)中，模型测算能耗排放因子与真实值的平均相对误差分别为3.7%和-1.7%，与不考虑内燃机开启状态相比，测算误差减少5.6%和4.3%；在实际交通状态下，采用传统燃油车的测算方法会导致混合动力汽车行驶平均速度为高速区间时油耗和CO2排放量被低估，当行驶平均速度为低速区间时油耗和CO2排放量会被高估。     

CRH3与CRH5型动车组中压供电方式对比分析

介绍了CRH3与CRH5型动车组车辆在各种情况下的中压分配情况,分别分析了CRH3、CRH5型动车组的中压供电方式及其控制条件和逻辑关系,对比分析了CRH3、CRH5型动车组中压供电的优缺点。供电技术的不断提升,使CRH3、CRH5型动车组的供电更加可靠、安全和稳定,同时也推动了高速列车技术的发展,使旅客乘坐更加舒适。     

SiC功率器件在轨道交通行业中的应用

为解决轨道交通牵引及辅助系统的轻量化等问题,宽禁带半导体器件如SiC器件的应用需求越来越大。SiC材料具有禁带宽度大、击穿场强高、电子饱和漂移速率快等特性,能满足在中大功率、高温、高频条件下工作的应用要求。简述了SiC器件相比传统硅基器件的突出优势及商业化和实验室研发情况,介绍了SiC功率器件在轨道交通行业中的发展现状,同时对其在未来轨道交通装备业的发展提出了建议和展望。     

隧道内列车振动对近接建筑物的影响分析北大核心

针对运营列车通过隧道时引起近接建筑物地面振动进行了现场测试,并对测试数据进行了功率谱、Z振级及1/3倍频程分析。在此基础上,利用有限元软件建立了围岩-隧道-轨道结构振动模型,对运营列车引起的建筑物振动进行了计算分析。结合实测与计算结果,对近接建筑物的振动特性进行了评价。结果表明:列车以速度300 km/h通过隧道时,地面振动功率谱主频白天集中在33.0 Hz左右,夜间集中在42.7 Hz左右,夜间的主频比白天大;地面各测点处Z振级的总体趋势是先波动式上升,再平缓波动,后逐渐波动式下降,地面Z振级主要集中在20~80 dB;1/3倍频程分频最大振级白天位于48.4~60.8 dB,夜间位于47.4~59.4 dB;列车通过隧道时基础处振动速度峰值整体呈波浪形分布,引起的地面振动速度小于0.045 mm/s,小于规范限值要求,对建筑物基础以及人体舒适度的影响较小;在缺乏大量实测结果的条件下,结合小样本实测结果,采用有限元计算结果进行振动响应评价具有一定的可行性。     

徐盐铁路引入徐州东枢纽牵引供电方案研究

徐盐铁路位于苏北地区,连接京沪、陇海、连镇、沿海四大铁路通道,是长三角城际网重要组成部分,也是京沪通道徐州-上海段的辅助通道,其引入徐州东枢纽以实现京沪高铁、郑徐高铁以及连徐高铁等4条线路的换乘,而枢纽地区牵引供电方案的合理性至关重要。因此,本文对徐盐铁路引入徐州东枢纽供电方案进行论证比较,并根据电分相检算分析提出推荐方案,以保证京沪高铁运行可靠性及工程实施的便捷性。     

无人救助艇的动力与控制系统选型

基于无人救助艇的性能要求,重点介绍动力与控制系统选型过程和原因。该艇选择磷酸铁锂电池为电源,并采用全电力推进、远程无线遥控控制技术。该无人救助艇的应用,增添了海洋救助方式。     

Integrated planning of static and dynamic charging infrastructure for electric vehicles

This paper investigates the optimal deployment of static and dynamic charging infrastructure considering the interdependency between transportation and power networks. Static infrastructure means plug-in charging stations, while the dynamic counterpart refers to electrified roads or charging lanes enabled by charging-while-driving technology. A network equilibrium model is first developed to capture the interactions among battery electric vehicles’ (BEVs) route choices, charging plans, and the prices of electricity. A mixed-integer bi-level program is then formulated to determine the deployment plan of charging infrastructure to minimize the total social cost of the coupled networks. Numerical examples are provided to demonstrate travel and charging plans of BEV drivers and the competitiveness of static and dynamic charging infrastructure. The numerical results on three networks suggest that (1) for individual BEV drivers, the choice between using charging lanes and charging stations is more sensitive to parameters including value of travel time, service fee markup, and battery size, but less sensitive to the charging rates and travel demand; (2) deploying more charging lanes is favorable for transportation networks with sparser topology while more charging stations can be more preferable for those denser networks.     

Joint deployment of charging stations and photovoltaic power plants for electric vehicles

The focus of this study is to jointly design charging stations and photovoltaic (PV) power plants with time-dependent charging fee, to improve the management of the coupled transportation and power systems. We first propose an efficient and extended label-setting algorithm to solve the EV joint routing and charging problem that considers recharging amount choices at different stations and loop movement cases. Then, a variational inequality problem is formulated to model the equilibrium of EV traffic on transportation networks, and an optimal power flow model is proposed to model the power network flow with PV power plants and optimally serve the EV charging requirements. Based on the above models for describing system states, we then formulate a model to simultaneously design charging stations, PV plants, and time-dependent charging fee. A surrogate-based optimization (SBO) algorithm is adopted to solve the model. Numerical examples demonstrate that the proposed SBO algorithm performs well. Additionally, important insights concerning the infrastructure design and price management of the coupled transportation and power networks are derived accordingly.     

船舶电站模拟器的信号采集

介绍了船舶仿真电站中模拟量和开关量统一输入的一种实现原理,并简要说明输入通道与计算机间的信息交换过程.     

移就的修辞方式修辞效果及翻译方法

移就是在特殊语言环境中改变词语搭配关系的一种临时迁就,是词语搭配的创造性运用。其常用的修辞方式分为移人于物、移物于人、移物于物三种。其修辞效果是能传达丰富的情感,产生出无穷的艺术张力。移就修辞格的翻译可采用直译法、位置还原法、状语化法和分译法等。