船舶电力系统谐波检测

谐波污染对船舶安全、稳定、高效地运行形成了严重的威胁.为对船舶电网中谐波进行严格的控制,先要对电网中的谐波进行检测.本文利用MATLAB仿真软件中的小波工具箱对船舶某变压器的现场谐波进行了检测.从仿真结果看,在基波幅值相对稳定的情况下,小波多分辨率分析可以比较准确地分离出船舶系统中的高次谐波,为谐波抑制提供了理论依据.     

基于PLC的船舶锅炉控制系统设计

根据船舶锅炉对控制系统的要求,采用可编程序逻辑控制器(PLC)对船舶锅炉控制系统进行改造,给出了硬件接口和软件编程。经试运行,设计方法具有结构简单、修改方便、可靠性高等优点。     

基于多源数据的武汉市轨道交通运行特征与发展策略

发展轨道交通是解决超大城市交通拥堵的有效途径之一,但出行需求与设施供给的匹配性、线网规划与空间规划的协同性成为影响其运行效率的关键。以武汉市为研究对象,在融合静态的轨道线网、人工调查,动态的手机信令、闸机刷卡、列车运行等多源数据的基础上,运用大数据分析技术,描绘居民出行活动特征,提出网络可达性测度等量化指标,研究轨道交通在大建设时期普遍存在的供需关系不均衡、系统功能不完善、耦合空间发展不紧密等问题。从功能设计、线网规划和运营管理等方面提出相应的发展策略,主张"主城成网新城通线"的规划思路,打造多网合一的多模式线网格局。     

A proposal for cost-related and market-oriented train running charges

This paper examines some key aspects of a charging system for promoting railway transport, including charges reflecting a clear relationship with costs (transparency) and charges reflecting the quality of the infrastructure manager's service. Train running charges recover track-related costs and can help to develop a charging system that meets these requirements. To orient train running charges to the market, a method for processing track maintenance and renewal costs is proposed whereby the quality of the service provided by an infrastructure is measured according to its utility to the railway undertaking. To achieve transparency, a single indicator is used for cost planning and the subsequent levying of costs on railway undertakings. The paper includes an example of how proposed train running charges would be calculated according to data from 14 European countries. The example shows that short-distance trains generate the lowest maintenance and renewal costs, followed by long-distance trains and freight trains.     

车市压力有增无减 自主品牌短期难改变 专访中国汽车工业协会常务副会长兼秘书长董扬

<正>下半年车市的走向,自主品牌如何突破困境,新能源汽车的发展,反垄断行为的影响及汽车产业政策的改革,针对这些热点问题,中国汽车工业协会常务副会长兼秘书长董扬接受了本刊的采访,表达了他的看法。目前,国内汽车行业一片躁动,无论是跨国车企还是自主品牌汽车企业都无法淡定。汽车行业新政策何时出台?国家发改委开展汽车市场"反垄断"调查结果是怎样的?自主品牌应该何去何从?新能源汽车在过渡期应如何提升?针对这些热点问题,记者采访了中国汽车工业协会常务副会长兼秘书长董扬。     

自主品牌汽车的“中国梦”何时到来 专访中国汽车技术研究中心主任赵航

<正>我国自主品牌汽车发展一直受制于汽车工业发展起步较晚所带来的薄弱根基,虽然因为价格因素,在国内市场占有一席之地,但在国际市场上却缺乏明显的竞争实力,几乎没有品牌能够跻身国际舞台,如今自主品牌面临的严峻问题更像是在夹缝中求生存,所以如何能够助推自主品牌发展,需要业界思考。     

城市客车油箱托架结构有限元分析与优化设计

对JS6106GHA城市客车的油箱托架结构进行有限元分析,找出缺陷,进行优化改进,以提高其可靠性,从而为合理地设计客车油箱托架结构提供参考。     

Urea-SCR system optimization with various combinations of mixer types and decomposition pipe lengths

The demand for NO_x after-treatment system has increased dramatically due to the stricter NO_x emission regulations for diesel vehicles. The urea-SCR system is one of the NO_x after-treatment methods found to be quite effective to meet the regulation requirement enforced by various authorities including the Euro-6. In order to develop an effective urea-SCR system, it is critical to establish an even distribution of reductant over the catalyst surface since this favorable distribution can increase reduction reaction and in turn, improve NO_x conversion efficiencies. In the current study, a number of design variations of the urea-SCR system which included two mixer types and three decomposition pipe lengths, were evaluated systematically using CFD analysis and experimental measurements. The purpose of the CFD analysis was to estimate the distribution of reductant within the urea-SCR system with a specific configuration and the purpose of the engine emission test was to measure the amount of NO_x reduction, respectively. The results from the systematic analysis revealed the relation between the reductant distribution over the SCR and the performance of the NO_x reduction.