气压对颗粒物质振动分离的影响 |
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引用本文: | 阎学群,史庆藩,厚美瑛,陆坤权,陈志强. 气压对颗粒物质振动分离的影响[J]. 物理, 2003, 32(11): 748-750 |
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作者姓名: | 阎学群 史庆藩 厚美瑛 陆坤权 陈志强 |
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作者单位: | 1. 中国科学院物理研究所,北京,100080;北京理工大学物理系,北京,100081 2. 中国科学院物理研究所,北京,100080 3. 中研院物理研究所,台北,115 |
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基金项目: | 国家自然科学基金 (批准号 :10 2 740 98)资助项目 |
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摘 要: | 文章作者系统地研究了垂直振动颗粒床中,在不同气压、颗粒尺寸以及密度情况下大球的运动规律。实验发现,系统处于真空状态或低气压时,大球总是向上运动。然而,当在通常大气压下,大球则会出现上升和下降两种运动状态。大球下降这种运动状态,只在大球的密度和颗粒床中颗粒尺寸足够小时才会出现,颗粒床中的负气压梯度导致大球下降。
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关 键 词: | 气压 颗粒物质 振动分离 巴西果效应 临界密度 负气压梯度 颗粒尺寸 垂直振动 |
修稿时间: | 2003-07-31 |
Effects of air on the segregation of particles in a shaken granular bed |
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Abstract: | The effects of interstitial air on t he motions of a large intruder in a shaken granular bed are studied experimental ly as a function of ambient air pressure, particle size of the bed, and the dens ity of the intruder. It is found that the intruder always rises from the granula r bed in the absence of air. However, the intruder can acquire both positive and negative buoyancy in the presence of air. Negative buoyancy can be observed onl y when both the density of the intruder and the particle size of the bed are sma ll enough. This negative buoyancy can be explained by the unusual air pressure d istribution found in the bed. |
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Keywords: | granular matter segregation Brazil net effe ct |
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