美国铁路车钩缓冲装置的发展（续完）

3　关节式连接器和牵引杆3.1　关节式连接器 　　关节式连接器在客车上已有多年的使用历史，主要用于20世纪30年代一些轻型流线型客车上，但很少在货车上运用。1968年为切萨皮克*俄亥俄铁路制造的活顶漏斗车，其车体间的连接采用由美国铸钢公司研制的关节式连接器，不过并没有收到此类车的订单。20世纪70年代后期，开始使用长途拖车，这时使用单节具有足够长度的车体运载2个拖车已不再合理。虽然可以制造用于运载单节拖车的较短的普通车辆，但这种车辆不能有效利用2个四轮转向架的承载能力。1977年制造出了采用关节式连接器、6节编组的列车，每个车体都运载1个拖车。关节式连接器以切萨皮克*俄亥俄漏斗车连接器为设计原型，相邻车体共同支承在1台四轮转向架上，允许相互间在水平和垂直方向上有一定转角。位于端部2节车的外端以常规方式支撑在独立的转向架上。这样，6节车体（1个车组）仅由7台转向架支承，如按普通结构则需要12台转向架。这种车每辆有10个车体，取得了很大成功。     

Determinants of airport retail revenue: a review of literature

ABSTRACT

As the airport retail industry continues to grow due to increasing travel demands, airport operators are increasingly developing their retail revenue potential to ensure financial viability. This study aims to provide a review of airport retail literature and identify the salient factors associated with passenger shopping behaviour. The paper presents a review of contemporary airport retail literature, covering a total of 50 studies from 1998 to 2018. The review identified 26 factors, which could broadly be grouped into five categories: airport/operator related; passengers' demographic related; passengers’ travel related; passengers’ psychological related and passengers’ resources related. In addition to providing a summary of the statistically significant factors across studies, the review identifies and discusses potential approaches for future research. These include the importance of considering both “to spend or not” decision and how much to spend and how most empirical studies focussed on the former; the gap in empirical analysis on the impact of airport terminal design layout on retail performance; and the gap in application of general consumer shopping behavioural models to airport retail problems. The paper concludes with the suggestion that we can build on the existing studies to develop a hybrid approach to solve several of the identified gaps simultaneously.     

自主神经功能检测对早期糖尿病自主神经功能损害的诊断价值

目的评价自主神经功能检测对早期糖尿病自主神经功能损害的诊断价值。方法50例2型糖尿病患者进行自主神经功能检查,即交感皮肤反应和心血管自主神经功能检测,并与30名健康人进行对比分析。结果糖尿病患者自主神经功能检测中交感皮肤反应,瓦氏比值和深呼吸时心率变异与对照组比较均有显著性差异(P<0.05),三者的异常率分别为70%,46%和50%;以交感皮肤反应的异常率最高,尤其以双下肢明显。立卧位血压差和冰水试验与对照组比较无显著性差异(P>0.05),其异常率分别为12%和16%。结论检测外周器官自主神经功能状态的方法中以交感皮肤反应的阳性率最高,可以作为检测早期糖尿病自主神经功能的常规筛选检查。     

Differences in single heavy vehicle crashes at intersections and midblocks

The objective of this research is to identify the factors differentiating between single heavy vehicle collisions at intersections and midblocks by using a binary logit model. Our results show that single vehicle crashes involving heavy vehicle at intersections are more likely to occur on main roads and highways, whereas crashes at midblocks are more likely to occur on divided two‐way roads, roads with special facilities or features (e.g. bridge) and roads with a higher percentage of heavy vehicle traffic. Intersection crashes are also more likely to involve vehicles that are turning left or right, resulting in angle crashes and vehicle overturn, whereas midblock crashes are more likely to involve vehicles on higher posted speed roads. Copyright © 2017 John Wiley & Sons, Ltd.     

White Layer of Hard Turned Surface by Sharp CBN Tool

IntroductionHard turning has been recognized as one of themost competitive clean machining technologies inreplacing of abrasive-based processes, with the de-velopment of high precision numerical machinetools and super-hardness tool material such as ce-ramic, CBN/PCBN (Cubic Boron Nitride/Poly-crystalline Cubic Boron Nitride)[1,2]. Hard turningoperation has shown geometrical flexibility, eco-nomics advantage, environmental friendliness, andsuperior surface integrity which is usually define…     

Determinants of motor vehicle crash fatalities using Bayesian model selection methods

Motor vehicle crashes continue to result in large numbers of fatalities each year and represent the leading cause of death for young persons. In 2006, for example, there were over 42,700 fatalities associated with these crashes. Understanding the causes of these crashes and methods to reduce them continues to be of great interest to economists, public health officials, and policy makers. We present in this paper statistical models using a rich set of panel data covering the period 1980 to 2007 by state and the District of Columbia. Our choice of variables is based on an extensive literature highlighting the importance of policy, safety, demographic, and economic determinants of fatality rates.     

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作为智能交通系统的一部分,在电子信息版显示的电子交通标识,由于能够为驾驶员提供清晰、准确且易于辨识的交通信息,在世界各地得到了日益广泛的应用。本文对韩国首尔市动态交通控制系统中的电子交通标识进行评价和设计。对之前研究中设计的部分标识改进,并在实际某路段的可变信息板显示试验。此外,通过部分驾驶员对这些交通标识的辨识进行分析,对不同方案进行评价,为确定最终的标识提供参考。结果表明,现有欧洲设计和韩国设计的表示交通事故的标志辨识正确率较低（分别为10%和43.5%）;表示拥堵和交通事件的标志辨识正确率在45%至55%间;欧洲设计的雪天警告标志的辨识正确率为17.5%,韩国设计的雪天警告标志相对易于辨识（正确率75.5%）。