19世纪初美国邮政使用了气动管精密系统，但伦敦使用了完全不同的方式，建立了这个小规模的铁路系统，只能用于包裹运输使用。
The USPS used an elaborate system ofpneumatic tubes during the early 19th century, but London took anentirely different approach and built this scaled-down railroad systemto be used only for parcels.
企业行为：悬挂轨道的直轨和弯轨，物料运输系统，气动钻机。
Activity: Running rails and curves for suspended monorails, material transport system, compressed-air cradle drilling machines.
为了提高运输效率，适应日益严格的节能减排政策以及促进环保，货车的空气动力学越来越受到人们的重视。
To improve the efficiency of transportation, adapt the stricter policies on energy-saving and emission reduction, it is paid more and more attentions on the truck aerodynamics.
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