Physical processes in wheel–rail contact and its implications on vehicle–track interaction

Friction within the wheel–rail contact highly influences all aspects of vehicle–track interaction. Models describing this frictional behaviour are of high relevance, for example, for reliable predictions on drive train dynamics. It has been shown by experiments, that the friction at a certain position on rail is not describable by only one number for the coefficient of friction. Beside the contact conditions (existence of liquids, solid third bodies, etc.) the vehicle speed, normal loading and contact geometry are further influencing factors. State-of-the-art models are not able to account for this sufficiently. Thus, an Extended-Creep-Force-Model was developed taking into account effects from third body layers. This model is able to describe all considered effects. In this way, a significant improvement of the prediction quality with respect to all aspects of vehicle–track interaction is expected.     

气阀故障对空气压缩机工作的影响及应对措施

文章分析了气阀故障对空气压缩机工作的影响,指出了气阀故障的判断方法,针对气阀故障提出了管理和检修时提高气阀工作可靠性的对策。这对于轮机管理人员及时准确的发现和排除空压机气阀故障具有一定的参考意义。     

高校学生自主购买教材的利弊分析

当前国内高校学生自主购买教材的势头越来越猛,它作为一种新生事物,逐步成为了各高校实行的趋势.根据笔者在教材管理部门工作的经验,通过对省内外高校教材部门实行教材学生自主购买的现状进行了深入的调查研究后,认真分析了这种现象的利弊,并对其如何兴利除弊作了一些思考.     

彩色陶瓷减速标线技术研究及应用

本文介绍了经课题组研发的彩色陶瓷减速标线的特点及应用范围。详细阐述了彩色陶瓷减速标线的视觉效果、陶瓷骨料性能、施工流程以及在湖南衡桂高速公路的应用情况。通过研究、分析和应用,一种既有震动减速又有视觉提醒作用的新型减速标线,具有技术先进性和独创性,有较大的推广应用前景。     

适用于重载交通的公路桥梁荷载标准研究

某一级公路具有明显的重载交通特征,在运营过程中也出现了严重的超载问题,为准确分析该一级公路上的汽车荷载,并确定其对该路上广泛使用的简支梁桥和连续梁桥的荷载作用,以WIM调查数据为基础并进行统计分析,利用蒙特卡洛方法随机数生成模拟自然车队的拟合荷载流.基于<公路工程结构可靠度设计统一标准>中计算荷载效应的可靠度理论,以拟合荷载流在产生的弯矩与公路Ⅰ级的弯矩效应比值为分析对象,确定了适应该一级公路重载交通荷载下计算桥梁结构内力的汽车荷载标准.针对该路重载交通的实际情况,给出了不同超载条件下适度提高汽车荷载等级的荷载放大系数.     

汽车座椅动态试验CAE分析及结构优化

通过构建某车型后排座椅骨架的有限元分析模型,根据欧洲经济委员会ECER17法规中关于座椅抗惯性的动态试验标准要求,对某汽车后排座椅进行抗惯性动态试验仿真分析。仿真分析结果揭示了座椅结构的应力集中位置,以及座椅结构中容易导致试验失效的薄弱环节,为正确设计以及合理调整改善结构方案提供了依据。通过优化设计,完善了产品的结构。     

几何非线性因素对密索型斜拉桥自振特性的影响

本文根据有限元法与有限位移理论,对一座密索型针拉桥进行了线性与 非线性的固有振动空间计算,并将计算结果作对比,以揭示几何非线性 因素时自振特性的影响。      

Evaluation of transit proximity effects on residential land prices: an empirical study in Austin,Texas

The Austin MetroRail line in Texas, U.S.A. began operations in 2010 and since then transit-oriented development projects have been fuelled around train stations. Traditional location theory holds that proximity to a transit station should be capitalized into land prices, and numerous empirical studies have demonstrated the effects with mixed results. However, to date no empirical study has investigated this relationship between the newly built rail line and land prices in Austin. This study fills the research gap and suggests a positive effect associated with transit proximity by employing spatial hedonic models. This study also contributes to the existing literature especially in the context of Texas cities where there is a lack of relevant research on transit-capitalization-related topics, and provides insights for decision-makers with different perspectives regarding further rail investment or transportation financing strategies such as value capture programs.     

肌梭传入对脊髓背角会聚神经元伤害性诱发反应的影响

本文用细胞外微电极记录技术,以大鼠脊髓背角WDR神经元伤害性诱发反应为痛反应的指标,观察了牵拉腓肠肌诱发的肌梭传入活动对脊髓背角WDR神经元伤害性反应的影响。结果如下:在观察到的80个WDR神经元中,有51个单位的晚串放电被牵拉诱发的肌梭传入活动所抑制,16个单位无反应,13个单位表现为兴奋。对有抑制作用的51个单位的进一步观察发现,瞬时牵拉的抑制作用强于持续牵拉,双侧牵拉的抑制作用强于单侧牵拉。提示肌梭作为肌肉丰厚处穴位的主要针感感受器,其传入活动具有镇痛作用。     

Consumer preferences for electric vehicles in lower tier cities of China: Evidences from south Jiangsu region

China is the world biggest market of electric vehicles (EVs) in terms of production and sales. Existing studies on consumer preferences for EVs in China have generally focused on first-tier cities, while little attention has been paid to the lower tier cities. This exploratory study investigates consumer preferences for EVs in lower tier cities of China, by collecting stated preference (SP) data in two second-tier cities and three third-tier cities in the south Jiangsu region of China. The discrete choice modeling analysis shows that Chinese consumers in lower-tier cities are generally sensitive to monetary attributes, charging service and driving range of EVs. They also perceive Chinese vehicle brands to be disadvantaged compared with European brands. When comparing the differences in second-tier versus third-tier cities, we find that consumers in third-tier cities are more sensitive to purchase price, subsidy of purchase, and coverage of charging stations than their second-tier counterparts. This study also highlights the role of different psychological effects, such as symbols of car ownership, normative-face influence, and risk aversion, in shaping consumer preferences for EVs in lower-tier cities of China. Our results provide important implications for contextualizing government policies and marketing strategies in line with the different sizes and characteristics of the cities in China.