四气囊空气悬架导向机构设计及故障分析

介绍后空气悬架四连杆导向机构的不同布置形式对悬架运动特性的影响。以国内某车型驱动桥空气悬架为例,对后桥移位原因进行分析,得出推力杆球铰的刚度大小不是后桥移位的主因,后桥移位主要与推力杆的安装座移位以及骑马螺栓松动有关的结论。     

自动变速车辆坡道行驶工况下换挡规律的研究

从采用一般换挡规律的AMT车辆在坡道行驶时容易出现的问题出发,分析了换挡循环问题、意外换挡问题和紧急制动问题的原因;提出通过计算理论加速度判断坡道工况的方法;制定修正后的坡道综合控制换挡规律。通过仿真分析,验证此方法可以有效解决各种坡道换挡问题。     

缸盖凸轮轴瓦盖拧紧机拧紧扳手自动变位装置研发与设计

文章介绍缸盖凸轮轴瓦盖拧紧机拧紧扳手自动变位装置的工作原理,针对发动机缸盖凸轮轴瓦盖装配过程中,对多品种和单一品种的多种不同间距的螺栓拧紧的问题,分析了拧紧扳手自动变位装置的设计要点及关键技术,并对缸盖凸轮轴瓦盖装配机拧紧扳手自动变位装置主要机构做了简单说明。     

物探船谐波综合治理方案研究

先进的三维物探船是电力推进形式的科考船,配置有变频控制的大功率推进电机和震源空压机,电站谐波必须进行控制,否则将导致高精度信号的采集和运算产生较大误差。本文以国内首艘自主设计的某三维物探船为例,根据投资预算、谐波控制指标、勘探作业特点、动力冗余等要求,对变频器选型论证、对发电机参数调整,制定全船谐波的综合治理方案,对同类船舶动力系统的设计具有借鉴意义。     

Part II: Policy instruments for sustainable road transport

Without questioning the fact that to achieve efficiency emitters should pay for the true costs of their actions (a core principle of economic policies such as pollution taxes), we find sufficient evidence in the literature to demonstrate that many other policy instruments can be used in combination with taxes and permits to ensure that the transport needs of the present generation can be met without compromising the ability of future generations to meet any needs of their own.The policies and policy aspects considered in this paper broadly fall into three categories: physical policies, soft policies, and knowledge policies. All three aim to bring about changes in consumers’ and firms’ behaviour, but in different ways. The first category includes policies with a physical infrastructure element: public transport, land use, walking and cycling, road construction, and freight transport. We also consider the particular challenges for mobility in developing countries, and how these may be addressed. Soft policies, on the other hand, are non-tangible aiming to bring about behavioural change by informing actors about the consequences of their transport choices, and potentially persuading them to change their behaviour. These measures include car sharing and car pooling, teleworking and teleshopping, eco-driving, as well as general information and advertising campaigns. Finally, knowledge policies emphasise the important role of investment in research and development for a sustainable model of mobility for the future.The main findings can be summarised as follows.

Physical policies

An increase in the use of public transport, combined with a decrease in the use of private cars, can reduce traffic congestion and, more importantly, carbon dioxide (CO₂) emissions, as public transport generally causes lower CO₂ emissions per passenger kilometre than private cars. Public transport fares are subsidised in most places, which can be justified by economies of scale and by the fact that public transport can reduce total road transport externalities. London, Singapore, Portland and Curitiba are all examples of good practice at government level, having achieved reliable, frequent and integrated public transport.Policies to increase public transport use must be part of an integrated policy. Integrated policy refers to integration across different modes of transport, different government objectives (such as the economy, health and the environment), considering the needs of different social groups, and coordinating action between the relevant government institutions. There is evidence that a lack of coordination can jeopardise the achievement of policy objectives.A sustainable model for transport policy also requires integration with land-use policies. These may be somewhat limited within the bounds of existing cities, but as cities grow and new cities are built, urban planners must put more emphasis on land use for sustainable transport in order to reduce congestion and CO₂ emissions. Sustainable land-use policy can direct urban development towards a form that allows public transport as well as walking and cycling to be at the core of urban mobility.Walking and cycling, which improve general health and produce no tailpipe emissions, constitute an excellent alternative to motorised transport on short-distance trips within towns and cities. The policies which can incentivise walking and cycling include crime reduction to make streets safer, well-maintained and clean pavements, attractive street furniture, safe crossings with shorter waiting times, dedicated cycle paths, showers in offices, and lower speed limits, to name but a few.Road construction and expansion used to be seen as one of the most promising ways to reduce traffic congestion. However, in the mid-1990s, the issue was reassessed and it was found that building and expanding roads, increased, rather than decreased, congestion, and ultimately induced higher levels of travel demand. The reason for this is that the extra capacity reduces the general cost of travelling and the less expensive the travel, the more it will be demanded. Regarding freight modal shift, road transport is much more polluting than rail per tonne-km of goods transported and therefore a shift towards greater use of rail in freight transport is desirable. Inadequate infrastructure is the main obstacle preventing this modal shift taking place.Developing countries face great mobility challenges: rural areas are often extremely poorly connected to transport infrastructure, such that, in contrast to the situation in developed countries, the benefits of road construction can strongly outweigh the total costs (including environmental ones). The main challenge, however, is to develop a solution to the problems arising from the combination of urbanisation and motorisation. Integration of transport and land-use policy will be key to rising to this challenge.

Soft policies

Car sharing and car clubs can also potentially reduce CO₂ emissions, although the aggregate reduction in congestion and emissions has not been measured with an adequate degree of precision in the literature. Teleworking and teleshopping can potentially reduce congestion and also CO₂ emissions. However, the evidence for this reduction is rather mixed, as it is unclear whether these measures lead to overall reductions in road transport.Eco-driving campaigns aim to inform and educate drivers in order to induce them to drive in a fuel-efficient and thus environmentally friendly way. There seems to be some consensus in the literature that eco-driving could lead to reductions in CO₂ emissions of around 10 per cent.Information and education policies have often been advocated as instruments which may affect behavioural change. We find in this paper that these types of measures are necessary, but not sufficient for behavioural change. Advertising and marketing may go a long way in changing peoples’ behaviour. In California, for example, Kahn (2007) finds the “Prius” effect: the Toyota Prius is preferred by consumers relative to other similarly green vehicles, probably due to extensive marketing and celebrity endorsements. Family life changes are also found to trigger changes in behaviour ( [Goodwin, 1989] and [106]). People whose lives are being changed by some important development (birth of a child, retirement, etc) tend to respond more to changes in the relative attractiveness of different transport modes. Advertising campaigns promoting a modal shift towards public transport, for instance, may thus be more successful if targeted at people in the process of important life transitions.

Knowledge policies

Research and Development is crucial for developing sustainable and low-carbon transport for the future, and it is essential that governments provide incentives to undertake R&D, so that new low-carbon technologies in the transport sector can be demonstrated and applied at a large scale.Finally, we consider the issue of policy combination and integration. There is evidence that the combination and integration of policies can lead to positive side-effects and synergies. Policy integration is crucial in order to rise to the challenges we face in moving towards a sustainable mobility model. We conclude that classical economic policies may be successfully combined with a number of policy measures discussed in this paper in order to achieve sustainability in transport.     

OFDM系统中的差分调制及其性能

基于子载波采用高阶差分幅度相移键控（MDAPSK）的正交频分复用（OFDM）系统，针对其独特的数据帧结构，提出并定义了OFDM系统的几种差分调制方案，仿真了不同信道环境下各种方案的误码性能。仿真结果表明，针对时间选择性和频率选择性衰落信道衰落程度的不同，在满足一定的时间相关性和（或）频率相关性的条件下，采用相应的时域和（或）频域差分调制方案，可以保证MDAPSK—OFDM系统的误比特率（BER）维持在较低的水平。     

城市轨道交通电动列车司机值乘方案的优化

以上海轨道交通3号线为例,对电动列车司机值乘的包乘制、轮乘制按实际效果和使用成本进行了优缺点分析;并在此基础上对司机作息安排、人员配置、运作管理情况综合进行优化,以期达到网络运营后节约人力成本的作用.     

基于SVM的二叉树多类分类算法在工程车辆挡位决策中的应用

为了解决工程车辆挡位决策这种典型的多类分类问题,在介绍自动变速器挡位决策基本原理的基础上,提出基于SVM的二叉树多类分类的挡位决策算法,将分类器分布在各个节点上,从而构成了多类SVM,并在制定换挡策略时,考虑了工作油泵所消耗发动机功率的波动问题。试验结果表明:该方法可根据车辆运行状态确定最佳挡位,从而及时准确地满足工程车辆自动换挡要求。     

单环非互易铁氧体移相器

为了研制自动跟踪同步通信卫星平板相控天线阵系统,对相控阵天线中的关键元件单环非互易铁氧体移相器进行了研究。利用双平板模型推导出了单环非互易铁氧体移相器的超越方程,并对其特性进行了讨论。根据超越方程对单环非互易铁氧体移相器的差相移随铁氧体厚度的变化进行了数值计算。结果表明随铁氧体厚度的增加,它的差相移增加。     

共享单车影响下小汽车出行方式转移机理研究

从小汽车到共享单车参与的出行模式转变是解决交通与环境问题的有效方法之一.本文通过对南京市 308名小汽车出行者进行问卷调查,探讨了共享单车影响下心理因素对小汽车出行模式转移的影响.通过建立改进后的技术接受模型,研究了感知有用性,感知易用性和感知健康价值对共享单车的态度,以及对出行方式转移意愿的影响.结果表明,通过作用于共享单车的态度,感知健康价值和感知易用性对转移意愿产生积极影响,感知有用性则产生直接的积极影响.共享单车可以在短途出行中替代小汽车,中距离下出行者最有可能受到激励从小汽车用户转变为潜在的共享单车接驳公共交通使用者,而长距离下共享单车较难影响小汽车出行者的出行方式选择.