Dégradation du comportement magnétique des tôles lors de leur mise en œuvre industrielle : mise en évidence expérimentale et modélisation

Degradation of the magnetic properties of electrical steels after industrial processing: experimental and numerical magneto-mechanical analyses. The magnetic properties of electrical steels strongly depend on their mechanical state. Hence, the final performances of electric machines are altered by the material degradation occurring during the manufacturing process. In the present study, we analyse the effect of assembling stresses on one hand and of punching on the other hand, on the global behaviour of the stator of an electrical machine. Stators of electrical machines were used to design and build simple devices in order to stress out the importance of these phenomena: the local degradation of the material induces a degradation of the global behaviour of the stator, and an increase of magnetic losses in particular. Simplified coupled finite element analyses are presented and a good agreement between simulated and experimental results is found.     

Amélioration du confort dynamique des trains dans l'optique d'une augmentation des vitesses

Improving dynamic train comfort to increase train speed. The permanent focus of railway competitiveness in the field of passenger transport is determined by several factors, one of which is the increase in traffic speed both on conventional and new very high speed lines. Without taking special precautions, such increases in speed could lead to an inevitable downgrading of the dynamic comfort of passengers, i.e. an increase in stresses especially of the transverse type affecting the train passengers. Such stresses are generated either by centrifugal forces when running through curves, or by vibrations transmitted by the bogies to the carbody. Alstom Transport and SNCF have pooled their efforts to prevent this deterioration and are currently undertaking research work along two lines. (1) The train tilting system as tested on a TGV of the Paris-Sud-Est class shows that there is a 15 percent speed increase on a given distance while simultaneously reducing by half the transverse acceleration to which the passengers are subjected to. (2) The so-called active transverse suspension helps to obtain at 350 km · h ⁻¹ a passenger comfort level superior to the one recorded on a TGV train running at 300 km · h ⁻¹ .     

光纤通信工程光纤光缆的验收

给出了光纤光缆产品的主要技术指标和测试方法,讨论了光纤光缆主要技术特性和光纤通信系统申通信容量、中继距离、接续损耗的关系,阐述了光纤光缆验收的基本原则和验收的一般方法。     

基于PCC架构提升EPON话音服务质量的方法研究

PCC是实现智能管道的关键技术,基于PCC架构可以实现网络资源的控制与管理,提升网络的服务质量。EPON是基于以太网的光接入网技术,其数据业务流量的突发性及分布的不均衡性,影响话音通信的质量。本文提出了基于PCC架构构建EPON智能管道以提升EPON话音服务质量的解决方案,给出了基于PCC的EPON智能管道的网络架构,重点讨论了通过对EPON话音、数据及视频业务的策略控制提高EPON话音服务质量的方法。