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siximeiwen

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[求助] 有没有人可以解释下扩散和弥散的区别? 已有1人参与

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西西很可怜

禁虫 (文坛精英)

十亿光年培优班学委——西西

【答案】应助回帖


感谢参与,应助指数 +1
siximeiwen(金币+1): 2011-12-13 10:16:47
zeng1986kai(金币+1): 谢谢应助! 2011-12-13 17:27:06
弥散一般是指烟雾一类在空气中扩散,重点是以气体为介质扩散
扩散意义很广,大于弥散
I can
2楼2011-12-12 22:16:19
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静水四叶草

金虫 (小有名气)

小笨蛋精灵

【答案】应助回帖


感谢参与,应助指数 +1
siximeiwen(金币+1): 2011-12-13 10:16:41
zeng1986kai(金币+1): 谢谢应助! 2011-12-13 17:27:13
扩散是一种现象,物理中的扩散现象,指的是分子的不规则运动。弥散是量子化学里的一种说法,它允许轨道占据更大空间,对于电子里原子核相对远的体系,能算出比较好的结果。
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3楼2011-12-13 09:14:03
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静水四叶草

金虫 (小有名气)

小笨蛋精灵

【答案】应助回帖


zeng1986kai(金币+1): 谢谢应助! 2011-12-13 17:27:25
引用回帖:
3楼: Originally posted by 静水四叶草 at 2011-12-13 09:14:03:
扩散是一种现象,物理中的扩散现象,指的是分子的不规则运动。弥散是量子化学里的一种说法,它允许轨道占据更大空间,对于电子里原子核相对远的体系,能算出比较好的结果。

不知对你有用没,我想我们现在需要的意思应该不仅仅是语言文字上的简单意思,应该是与物理、化学有关的意思吧。希望对你有帮助。
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4楼2011-12-13 10:46:12
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jxph095258

新虫 (初入文坛)

【答案】应助回帖

扩散diffusion,弥散dispersion
Diffusion and dispersion are different modes of mass transfer in that the mechanisms behind them are different. Diffusion is the spreading out of material that occurs due to the random thermal motion of molecules, and is characterized by molecules behaving as "random walkers".

In order to understand dispersion, consider a convective flow superposed over the diffusion. If the flow velocity is uniform everywhere (i.e. "plug flow", then molecules at different places in the flow will move with the same convective velocity, and it is only diffusion rate which will differentiate between them. However, now consider a flow in which gradients exist, for example fully developed pipe flow. The fluid at the center of the pipe is moving much faster than the fluid close to the walls. If there is diffusion in the radial direction, then molecules can hop over from one streamline to the next, and thereby will be transported over different distances due to the difference in velocities. This smearing out (or being transported over different distances) caused indirectly by diffusion (in the radial direction) is the physical interpretation of dispersion. Surprisingly, the amount of dispersion reduces with increasing diffusion coefficient. This is because, then, the molecules will just be hopping from one streamline to another constantly and will not get "enough" time to be transported far from each other. The above physical model of dispersion is explained beautifully in the book "Analysis of Transport Phenomena" by William M. Deen. You should have a look, if possible!
——QUORA

http://www.zhihu.com/question/23914350/answer/55768081
来源:知乎
5楼2016-03-25 09:08:55
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