Results 21 to 30 of about 13,853 (179)

Numerical study on the morphology and fractal dimension of two-dimensional magnetic clusters(二维磁性团簇形貌及其分形维数的数值研究)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2008
在扩散限制凝聚(DLA)模型基础上,采用Monte Carlo方法模拟了具有幂次相互作用的磁性粒子动力学凝聚过程.重点研究了在不同幂指数α值下团簇的形貌及其分形维数Df随耦合参数βC的演化规律.模拟结果表明:对于较大的α值,即α=5时,团簇形貌随βC的变化较小,其分形维数Df 一般在1.60~1.70;而随着α值的减小,团簇形貌随参数βC有一明显的演化过程,在模拟范围内,分形维数Df在1.20~1.95.
WANGFeng-fei(王凤飞)   +2 more
doaj   +1 more source

PFU微型生物群落监测中异养性指数的应用研究及其分形分析 [PDF]

open access: yes, 2004
对常德和汉江的异养性指数(HI)进行了分形分析,表明异养性指数在二维空间分布具有自相似性.异养性指数数据点与化学综合污染指数(P)数据点在双对数坐标中分段拟合时,当常德和汉江的LogP分别小于0 602和0 493时,常德和汉江的分形维数分别为0 39332和0 74110;当常德和汉江的LogP大于0 602和0 493时,常德和汉江的分形维数分别为0 30678和0 27239.拐点的出现表明异养性指数的变化在两个尺度域内遵从着不同的规律.拐点尺度以前,分维数较高,表明群落组成复杂 ...
冯伟松,沈韫芬
core  

Fracture network complexity of tight sandstone and its influencing factors [PDF]

open access: yes
Objective  Fracture network analysis plays an important role in oil and gas exploration and development. However, complexity analysis of tight sandstone fracture networks and their control factors is relatively lagging.
FENG Xingqiang   +4 more
core   +1 more source

Bifunctional Competitive Structure of Biomass Carbon‐Derived Metacomposites for Tunable ε′‐Near‐Zero and ε′‐Negative Responses

open access: yesRare Metals, EarlyView.
ABSTRACT Regulating negative parameters of metacomposites is mainly limited by their unclear mechanisms, which affects their practical applications in new sensing, communication, electromagnetic (EM) protection and other fields. This work proposes a dual‐functional competitive design strategy based on the waste corncob‐derived carbon/polyaniline ...
Qiuyun Yang   +4 more
wiley   +1 more source

A calculational model for 3D fault complexity based on curvature analysis and fractal dimensions [PDF]

open access: yes
Objective and Methods Faults are identified as one of the most threatening geological structural factors among hidden disaster-causing factors in coal mines. However, the 3D quantitative assessment of them remains challenging.
Chenguang LIU   +8 more
core   +1 more source

Effect of calcium lignosulfonate on the deformation and failure characteristics of cementing stone and its modification mechanism [PDF]

open access: yes, 2023
In the coalbed methane extraction of surface wells in the mining area, the mining of coal seam in working face will cause a significant disturbance to overlying rock layer, which in turn will lead to the deformation and damage of surface wells.
Quanle ZOU   +4 more
core   +1 more source

Differences in characteristics between naturalized threatened plants and other threatened plants

open access: yesConservation Biology, EarlyView.
Abstract Many non‐native plant species introduced by humans have become naturalized. At the same time many species are threatened in their native range. However, the number of plant species threatened in their native range that are naturalized elsewhere remains unknown.
Weihan Zhao   +10 more
wiley   +1 more source

Fractal characteristics and related affecting factors of particle size distribution in mangrove soils in Dongzhai Harbor of Hainan [PDF]

open access: yes, 2008
应用分形理论分析了海南东寨港红树林土壤粒径分布的分形特征及其影响因素,海南东寨港土壤的分形维数为2.302~2.575,分形维数的大小与土壤中的粘粒、盐分、有机质、全氮含量呈显著正相关,外滩红树林土壤的分形维数低于中滩和内滩;随着土壤质地由砂壤土、轻壤土、中壤土、重壤土的变化,分形维数逐渐增大;从陆到海土壤分形维数逐渐减小。群落类型、土壤质地、滩位、含盐量、有机质、全氮含量等是影响海南东寨港红树林土壤分形维数的主要因子。The analysis with fractal theory on the ...
刘美龄, 叶勇, 唐飞龙, 曹长青
core  

Representation of obligate groundwater‐dwelling copepod diversity in European protected areas

open access: yesConservation Biology, EarlyView.
Abstract Groundwaters sustain diverse surface ecosystems and are populated by metazoan species, mostly invertebrates, that provide fundamental ecological functions and are often of prominent conservation value due to narrow endemism and high phylogenetic rarity.
Francesco Cerasoli   +7 more
wiley   +1 more source

New method of calculation Boolean difference based on bj map(基于bj图计算逻辑函数布尔差分的新方法)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2004
分析了逻辑函数在部分变量取反时的bj图和降维bj图,在此基础上提出了用bj图和降维bj图计算逻辑函数的一阶布尔差分和二阶布尔差分的图形方法.实例表明,该图形方法有直观、简单等特点.它能给出逻辑函数布尔差分的最简与/异或式.
WUGui-chu(吴桂初)   +2 more
doaj   +1 more source

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