With Shanghai being the center of the region, Yangtze River Delta Region is targeted to build up a "Three Hours' Transportation Circle" by 2010.

以上海为中心，长江三角洲以于二零一零年建立“三小时经济圈”为目标。

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This paper introduces three kinds of CNC turning method combined with practical example, concentric circle turning, center shifting turning and taper profile composition turning.

文章结合编程实例介绍了球弧数控车削三种常用的工艺方法，即车圆法、移圆法、车锥法。

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