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在中华帝国历史上的第一个千年里,中国与欧亚大陆其他地区之间的联系主要是通过陆路,由此可见,当时的中华帝国基本上是一个自给自足的农业社会.中唐以后,情况有所改变,来自波斯、阿拉伯、印度、南亚、日本、朝鲜半岛的商船开始频繁地出入中国沿海的主要港埠.中国对新兴的海上贸易形势迅速作出反应,并在12至15世纪之间,逐步地发展成为一个重要的海上强国,拥有一支由中国帆船装备而成的富有战斗力的海军,控制着从印度东南沿海到南中国海及中国东海的航路. 相似文献
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A Review of Four-Wheel Steering Studies from the Viewpoint of Vehicle Dynamics and Control 总被引:8,自引:0,他引:8
Yoshimi FURUKAWA Naohiro YUHARA Shoichi SANO Hideo TAKEDA Yoshinobu MATSUSHITA 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1989,18(1):151-186
As the four-wheel steering (4WS) system has great potentials, many researchers' attention was attracted to this technique and active research was made. As a result, passenger cars equipped with 4WS systems were put on the market a few years ago. This report tries to identify the essential elements of the 4WS technology in terms of vehicledynamics and control techniques. Based on the findings of this investigation, the report gives an outline and perspective of the research areas involved. 相似文献
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