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Movement Patterns of the Eastern Chipmunk (<i>Tamias striatus</i>) in Four Fragmented Landscapes of Prince Edward Island, Canada
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作者 Sheldon B. Opps Leslie A. Cudmore Marina Silva-Opps 《Open Journal of Ecology》 2020年第10期688-715,共28页
The analysis of animal movement patterns can provide important information on animals’ responses to habitat features. In this study, the movement paths of eastern chipmunks (<em>Tamias striatus</em>) were... The analysis of animal movement patterns can provide important information on animals’ responses to habitat features. In this study, the movement paths of eastern chipmunks (<em>Tamias striatus</em>) were examined in four landscapes, with different levels of habitat fragmentation, using either fluorescent powdering or spool-and-line tracking. Descriptions of the tree and ground vegetation communities were performed in the vicinity of the trail to obtain information on habitat use and habitat selection. Several key movement variables were calculated, including the total path length, net distance, fractal dimension, and radius of gyration. Despite statistically significant differences in some of the movement metrics between the four landscapes, the overall movement patterns were generically the same for all of chipmunk paths examined in this study. The data were compared to trends expected based on random or correlated random walks, as well as Lévy-walk models. The mean squared net displacement did not support the correlated random walk predictions, except at smaller spatial scales, but overall demonstrated Lévy-like super diffusive behaviour. Lévy-like patterns were also confirmed from the move-length distributions that demonstrated truncated-tail power-law behaviour. Although this would suggest invariance of the movement patterns at all spatial scales studied, fractal analysis revealed at least two transitions in movement patterns at scales of around 2 and 5 m. The transition point at 2 m was negatively correlated with the density of small trees, while the transition at ~5 m was positively correlated with the spatial distribution of large trees. As the habitat-preference data showed that small trees are among the least preferred habitat component, while large trees were among the most preferred habitat, chipmunks are likely to alter their movement behaviour to avoid small trees, and attracted towards large trees possibly to avoid predators. Overall, we determined three principal domains of movement: at small 展开更多
关键词 Fluorescent Powder spool-and-line Fractal Radius of Gyration Lévy Walk Correlated Random Walk Small Mammals Prince Edward Island
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供热系统中调节阀的研究与应用 被引量:5
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作者 史登峰 衣惠昌 陶进 《暖通空调》 EI 北大核心 1997年第2期57-61,共5页
依据调节阀流量特性的数学方程,导出了流量特性分别为直线型和等百分比型调节阀流通截面积的计算公式,指出了现有调节阀阀芯形状设计中存在的问题,分析了供热系统中调节阀的选用原则,认为应根据流通能力来计算选择调节阀的口径,而... 依据调节阀流量特性的数学方程,导出了流量特性分别为直线型和等百分比型调节阀流通截面积的计算公式,指出了现有调节阀阀芯形状设计中存在的问题,分析了供热系统中调节阀的选用原则,认为应根据流通能力来计算选择调节阀的口径,而不是由连接管的管径来确定,并认为调节阀的安装地点不同,其计算公式中的系数有差别。 展开更多
关键词 阀芯型线 调节阀 供热系统 流通能力
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调节阀阀芯型线的优化设计与流阻分析 被引量:2
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作者 刘磊 何世权 《轻工学报》 CAS 2017年第3期96-101,共6页
针对传统的调节阀阀芯型线设计无法有效减小压降的问题,采用正交多项式作最小二乘拟合的方法对型线进行优化,得到新的曲线方程,将该方程提取到AutoCAD中设计阀芯型线.数值模拟结果表明,新设计的阀芯型线的流阻系数比原来下降35%,且进出... 针对传统的调节阀阀芯型线设计无法有效减小压降的问题,采用正交多项式作最小二乘拟合的方法对型线进行优化,得到新的曲线方程,将该方程提取到AutoCAD中设计阀芯型线.数值模拟结果表明,新设计的阀芯型线的流阻系数比原来下降35%,且进出口压降减小,实现了节能的目的. 展开更多
关键词 调节阀 阀芯型线 数值模拟 流阻
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