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Analytical evaluation of the plasma dispersion function for a Fermi-Dirac distribution
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作者 B.A.Mamedov 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期400-404,共5页
An efficient method for the analytic evaluation of the plasma dispersion function for the Fermi-Dirac distribution is proposed.The new method has been developed using the binomial expansion theorem and the Gamma funct... An efficient method for the analytic evaluation of the plasma dispersion function for the Fermi-Dirac distribution is proposed.The new method has been developed using the binomial expansion theorem and the Gamma functions.The general formulas obtained for the plasma dispersion function are utilized for the evaluation of the response function.The resulting series present better convergence rates.Several acceleration techniques are combined to further improve the efficiency.The obtained results for the plasma dispersion function are in good agreement with the known numerical data. 展开更多
关键词 Fermi Dirac distribution plasma dispersion function binomial coefficients incompletegamma functions
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Distribution of Fe and adsorption of NH_3 in mordenite:a computational study
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作者 郭海燕 任君 +1 位作者 冯刚 曹端林 《Journal of Measurement Science and Instrumentation》 CAS 2014年第1期80-87,共8页
The distribution of Fe and the adsorption of NH3 in H-[Fe]MOR (mordenite) were investigated using dispersion corrected density functional theory (DFT-D2).Based on the results,it can be found that the most favorabl... The distribution of Fe and the adsorption of NH3 in H-[Fe]MOR (mordenite) were investigated using dispersion corrected density functional theory (DFT-D2).Based on the results,it can be found that the most favorable site for the distribution of Fe is T1O6,followed by T2O5,T4O2 and T3O1,and energy differences for Fe in different T sites are less than 0.09 eV,indicating that Fe atoms may distribute in all kinds of T sites in MOR.In addition,the adsorption energies for NH3 at each crystallographic position of H-[Fe]MOR were also determined.Finally,it can be concluded that the Br(o)nsted acid site at T2O5 is stronger than the other acid sites,and the adsorption of NH3 on Br(o)nsted acid sites is more stable than on Lewis acid sites. 展开更多
关键词 mordenite (MOR) distribution of Fe adsorption of NH3 dispersion corrected density functional theory (DFT-D2) calculations
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Excitation of Elastic Wave of an Arbitrary Plane Source on Surface of a Multilayered Medium 被引量:1
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作者 张碧星 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第10期2803-2806,共4页
We investigate the elastic waves excited by an arbitrary plane piezoelectric source on the surface of a multilayered medium. Based on the previous studies, the 2D elastic wavefield in the multilayered medium is extend... We investigate the elastic waves excited by an arbitrary plane piezoelectric source on the surface of a multilayered medium. Based on the previous studies, the 2D elastic wavefield in the multilayered medium is extended to 3D space. The propagator matrix for the 3D wavefield is investigated and the displacement-stress response for the boundary conditions is obtained. The excitation and propagation of the Rayleigh and Love waves are analysed further. It is found that the propagation velocity of the Rayleigh and Love waves does not depend on the propagation azimuth θ in the plane parallel to the free surface of the multilayered medium while the displacement is strongly dependent on the azimuth θ. 展开更多
关键词 DISPERSION function COMPUTATIONS UNLIMITED FREQUENCY VALUES
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Relationship between species richness,taxonomic distinctness,functional diversity,and local contribution toβdiversity and effects of habitat disturbance in the riparian spider community of the Ganga River,India
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作者 Kritish De Amar Paul Singh +4 位作者 Arkojyoti Sarkar Kritika Singh Manju Siliwal Virendra Prasad Uniyal Syed Ainul Hussain 《Ecological Processes》 SCIE EI CSCD 2023年第1期204-216,共13页
Background In the riverine riparian ecosystem,particularly in India,the knowledge of the effects of habitat disturbance on taxonomic distinctness,functional diversity,and local contribution toβdiversity(LCBD)of spide... Background In the riverine riparian ecosystem,particularly in India,the knowledge of the effects of habitat disturbance on taxonomic distinctness,functional diversity,and local contribution toβdiversity(LCBD)of spider community is elusive.The present study examined the relationships between the index of taxonomic distinctness(Δ^(+)),index of variation in taxonomic distinctness(λ^(+)),functional evenness(FEve),functional divergence(FDiv),functional dispersion(FDis),and LCBD of spider community of the Ganga River and the effects of habitat disturbance on these indices.A total of 27 sampling sites were selected along the bank of the Ganga River.Based on the rating of the disturbance scores,the sites were classified into lowly,moderately,and highly disturbed sites.To understand the relationships between species richness,Δ^(+),λ^(+),FDis,FDiv,FEve,LCBD,and habitat disturbance score,Pearson’s correlation was calculated,followed by the linear regression model.The one-way multivariate analysis of variance was used to find differences in taxonomic distinctness and functional diversity in the different disturbed sites.Results Significant relationships were found betweenλ^(+)andΔ^(+),FDis andΔ^(+),FDis andλ^(+),FDiv and species richness,FEve and species richness,FEve andλ^(+),FEve and habitat disturbance,LCBD and FEve,and LCBD and habitat disturbance.A significant difference was present in the indices of functional diversity between the lowly,moderately,and highly disturbed sites.Agriculture,garbage dump,human settlement,and created embankment influenced the spider community’sλ^(+),FEve,and LCBD.Conclusion Unrestrained anthropogenic activities exacerbate habitat disturbance by affecting ecological processes.Thus,understanding linkages between ecosystem disturbance,taxonomic,functional,andβdiversity can be fundamental to managing and conserving natural resources.This work highlights the importance of including taxonomic and functional diversity to comprehend the impact of habitat disturbance on riverine riparian spiders beyond just the number of species.An integrated taxonomic and functional diversity approach coupled withβdiversity can be used to support environmental assessment,restoration,and conservation planning of the biological resources of the Ganges River. 展开更多
关键词 Habitat disturbance Taxonomic distinctness functional evenness functional divergence functional dispersion Local contribution to beta diversity Spider community Riparian area Ganga River
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Functional traits of tree species with phylogenetic signal co-vary with environmental niches in two large forest dynamics plots 被引量:20
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作者 Jie Yang Xiuqin Ci +4 位作者 Mengmeng Lu Guocheng Zhang Min Cao Jie Li Luxiang Lin 《Journal of Plant Ecology》 SCIE 2014年第2期115-125,共11页
Aims While using phylogenetic and functional approaches to test the mechanisms of community assembly,functional traits often act as the proxy of niches.However,there is little detailed knowledge regarding the correlat... Aims While using phylogenetic and functional approaches to test the mechanisms of community assembly,functional traits often act as the proxy of niches.However,there is little detailed knowledge regarding the correlation between functional traits of tree species and their niches in local communities.We suggest that the co-varying correlation between functional traits and niches should be the premise for using phylogenetic and functional approaches to test mechanisms of community assembly.Using functional traits,phylogenetic and environmental data,this study aims to answer the questions:(i)within local communities,do functional traits of co-occurring species covary with their environmental niches at the species level?and(ii)what is the key ecological process underlying community assembly in Xishuangbanna and Ailaoshan forest dynamic plots(FDPs)?Methods We measured seven functional traits of 229 and 36 common species in Xishuangbanna and Ailaoshan FDPs in tropical and subtropical China,respectively.We also quantified the environmental niches for these species based on conditional probability.We then analyzed the correlations between functional traits and environmental niches using phylogenetic independent contrasts.After examining phylogenetic signals of functional traits using Pagel’sλ,we quantified the phylogenetic and functional dispersion along environmental gradients within local tree communities.Important Findings For target species,functional traits do co-vary with environmental niches at the species level in both of the FDPs,supporting that functional traits can be used as a proxy for local-scale environmental niches.Functional traits show significant phylogenetic signals in both of the FDPs.We found that the phylogenetic and functional dispersion were significantly clustered along topographical gradients in the Ailaoshan FDP but overdispersion in the Xishuangbanna FDP.These patterns of phylogenetic and functional dispersion suggest that environmental filtering plays a key role in structuring local tree assemblages in Ailaoshan FDP,while competition exclusion plays a key role in Xishuangbanna FDP. 展开更多
关键词 forest dynamics plot local scale phylogenetic independent contrast phylogenetic signal phylogenetic dispersion functional dispersion
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