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纳板河流域林分空间结构的林木竞争探究
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作者 赖叶青 张远荣 +1 位作者 胡明星 张发山 《林业调查规划》 2019年第2期36-45,共10页
林分空间结构一般包括树种混交、林木竞争和林分中林木分布格局等三个方面,对它们一般分别采用竞争指数中的混交度、大小比数及角尺度来进行描述。在纳板河流域不同群落类型林分中设置样地进行调查分析,结果表明,从空间竞争中的混交度... 林分空间结构一般包括树种混交、林木竞争和林分中林木分布格局等三个方面,对它们一般分别采用竞争指数中的混交度、大小比数及角尺度来进行描述。在纳板河流域不同群落类型林分中设置样地进行调查分析,结果表明,从空间竞争中的混交度方面看,热带雨林、季雨林、季风常绿阔叶林及山地雨林林木主要集中在极强度混交之中,只有少许树种会出现强度混交和中度混交,几乎不出现零度混交和弱度混交,稳定性较高;而落叶阔叶林的稳定性由于样地位置不一而表现较大差距,有较稳定的,也有稳定性较差的。从大小比数看,保护区主要林分内树种大小分化较大,优势程度从优势至劣势都有不均等的分布。各林分的角尺度为0.22~0.34,说明样地林木分布格局为均匀分布。 展开更多
关键词 林分空间结构 混交度 角尺度 大小比数 林木分布格局 纳板河自然保护区
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Analysis of the residence time distribution in rotary kilns and the effect of particle sizes
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作者 Haozhi Jie Fabian Herz Xiaoyan Liu 《Particuology》 2025年第8期193-205,共13页
In this study, a mathematical model based on the segregation-induced ring-core structure was developed to predict the residence time and axial velocity of particles of different sizes within a rotary kiln. Validation ... In this study, a mathematical model based on the segregation-induced ring-core structure was developed to predict the residence time and axial velocity of particles of different sizes within a rotary kiln. Validation experiments were conducted using a pilot-scale rotary kiln with bidisperse particle systems comprising particle sizes of 0.7 mm, 2 mm, and 4 mm. The entire process was recorded using video analysis, which enabled the tracking of tracer particle movement from the inlet to the outlet. Based on the recorded data, the average axial velocity for each particle size across different kiln regions was determined. At the outlet, the tracer particles were analyzed using statistical methods and diffusion theory, allowing for the calculation of the residence time distribution (RTD), mean residence time (MRT), variance, axial dispersion coefficient (Dz), and Peclet number (Pe). The experimentally obtained MRT exhibited strong agreement with the predictions of the mathematical ring-core structure model, confirming its accuracy and reliability. Additionally, the influence of particle size and mixing behavior was systematically evaluated by varying particle size ratios and mass concentrations. 展开更多
关键词 Rotary kiln Residence time distribution sizeratio Bidisperse particle
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