We seek to characterize the local state of deformation of the material in a neighborhood of a point P. Consider two points P and Q in the undeformed

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一、~the+~est+名词+(that)+主词 have ever+seen(own/heard/had/read, etc) the most+形容词名词+(tht)+主词+ have ever+seen( known/heard/had/read, etc) 例句: Helen is the most beautiful girl that have ever seen 海伦是我所看过最美丽的女孩

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早在英国爱德华二世(1284~1327)年代,这位国王就曾想通过禁止使用煤来解决 燃煤产生的烟气污染问题。他曾颁布了一道法令:“无论是谁被发现燃烧煤,他就是 有罪的,都将受到杀头的惩罚”。由此可见,大气污染自古有之。如同其它污染控制 样,大气污染控制技术和工程、设备也是在大气污染到了一定的程度、顺应时代需 要的产物:控制技术的研究与工程应用的主要推动原因是严重的大气污染事件的刺 美国的 Donora是一座钢铁小城,在1948年仅有3家主要工厂:钢铁厂、电线厂 和锌板厂