Traditionally,patch-based analysis at the landscape scale fragmentation has been used in the study of landscape ecology while the study of boundary and node has not been considered as much detail until recently.This s...Traditionally,patch-based analysis at the landscape scale fragmentation has been used in the study of landscape ecology while the study of boundary and node has not been considered as much detail until recently.This study investigated the possibility of applying boundary-and node-based methods in landscape pattern analysis to the upper reaches of the Minjiang River in the southwestern China.Boundary-based and node-based landscape indices were selected to be used in analyzing changes in landscape patterns,and the results were compared with analysis using traditional pattern indices.We compared the responses of patch-area-based,boundary-length-based and node-number-based indices,and concluded that boundary-based and node-based indices are more sensitive to disturbance than patch-based indices with various patterns,and node-based indices are even more sensitive than boundary-based ones.Thus,the results suggest that boundary-based and node-based pattern analysis methods provide helpful supplementary information to traditional patch-based pattern analysis methods.The results about pattern dynamics of landscapes in the upper reaches of the Minjiang River based on boundaries and nodes showed that with human disturbance,the dominance of forest landscape was weakened by other landscape types;thus the landscape pattern of the study area became more homogeneous and the boundary network became more complex.These changes further augmented disturbance interfaces in the landscape and increased the possibilities of further landscape fragmentation.展开更多
An Acoustic Doppler Current Profiler （ADCP） observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters （SPM） distribution pattern. The SPM concentra...An Acoustic Doppler Current Profiler （ADCP） observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters （SPM） distribution pattern. The SPM concentration could be semi-quantitatively represented by backscatter intensity （Sv）, converted by the echo intensity （E/） of ADCP. Results show two types of SPM in the water column： the quasi-biological SPM and quasi-mineral SPM. The quasi-biological SPM mainly exists in summer half year and is con- centrated above the thermocline. It has periodically diurnal variations with high concentration at night and low concentration in the daytime. The quasi-mineral SPM is located in lower part of the water column, with similar relation to monthly tidal current variation all year round. However, the daily quasi-mineral SPM distribution patterns vary between summer and winter half year. The sunlight is thought to be the origin factor leading to the diurnally vertical motion of the biological features, which might cause the diurnal Sv variation. Unlike in winter half year when tidal current is relatively single driving force of the monthly SPM pattern, the high speed current near the thermocline is also responsible for the concentration of quasi-mineral SPM in summer half year. The sediment input difference between summer and winter half year contribute to the varied daily variation of quasi-mineral SPM with re-suspended SPM ir~ winter and sediments from Yellow Sea Mud Area （YSMA） in summer. The seasonal variations in hydrodynamics, water structure and heavy-wind incidents are the primary factors influencing the differential seasonal SPM distribution patterns.展开更多
In this note, we would like to point out that （i） of Corollary 1 given by Zhang et al. （cf Commun. Theor. Phys. 39 （2003） 381） is incorrect in general.
In this paper, we study a delayed SIRS model with nonlocal diffusion. The well posedness of the model is investigated. Furthermore, we concern with the problem of traveling wave solutions. By using the partial quasi-m...In this paper, we study a delayed SIRS model with nonlocal diffusion. The well posedness of the model is investigated. Furthermore, we concern with the problem of traveling wave solutions. By using the partial quasi-monotone condition, cross-iteration scheme and fixed-point theorem, sufficient conditions are derived for the existence of traveling waves connecting the two equilibria which depends on the existence of a pair of upper solution and lower solution. We in fact construct a pair of upper solution and lower solution concretely to guarantee the existence of traveling waves.展开更多
In this work,we propose incorporating the finite cell method(FCM)into the absolute nodal coordinate formulation(ANCF)to improve the efficiency and robustness of ANCF elements in simulating structures with complex loca...In this work,we propose incorporating the finite cell method(FCM)into the absolute nodal coordinate formulation(ANCF)to improve the efficiency and robustness of ANCF elements in simulating structures with complex local features.In addition,an adaptive subdomain integration method based on a triangulation technique is devised to avoid excessive subdivisions,largely reducing the computational cost.Numerical examples demonstrate the effectiveness of the proposed method in large deformation,large rotation and dynamics simulation.展开更多
基金Under the auspices of Major State Basic Research Development Program of China(No.2006CB403201)
文摘Traditionally,patch-based analysis at the landscape scale fragmentation has been used in the study of landscape ecology while the study of boundary and node has not been considered as much detail until recently.This study investigated the possibility of applying boundary-and node-based methods in landscape pattern analysis to the upper reaches of the Minjiang River in the southwestern China.Boundary-based and node-based landscape indices were selected to be used in analyzing changes in landscape patterns,and the results were compared with analysis using traditional pattern indices.We compared the responses of patch-area-based,boundary-length-based and node-number-based indices,and concluded that boundary-based and node-based indices are more sensitive to disturbance than patch-based indices with various patterns,and node-based indices are even more sensitive than boundary-based ones.Thus,the results suggest that boundary-based and node-based pattern analysis methods provide helpful supplementary information to traditional patch-based pattern analysis methods.The results about pattern dynamics of landscapes in the upper reaches of the Minjiang River based on boundaries and nodes showed that with human disturbance,the dominance of forest landscape was weakened by other landscape types;thus the landscape pattern of the study area became more homogeneous and the boundary network became more complex.These changes further augmented disturbance interfaces in the landscape and increased the possibilities of further landscape fragmentation.
基金supported by the National Natural Science Foundation of China (Grant No. 41030856)National 973 Project of China (Grant No. 2005CB422304)+1 种基金the Project of Taishan Scholarsupport of the R/V Dongfanghong 2 and Shared Voyage of the National Nature Science Foundation of China
文摘An Acoustic Doppler Current Profiler （ADCP） observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters （SPM） distribution pattern. The SPM concentration could be semi-quantitatively represented by backscatter intensity （Sv）, converted by the echo intensity （E/） of ADCP. Results show two types of SPM in the water column： the quasi-biological SPM and quasi-mineral SPM. The quasi-biological SPM mainly exists in summer half year and is con- centrated above the thermocline. It has periodically diurnal variations with high concentration at night and low concentration in the daytime. The quasi-mineral SPM is located in lower part of the water column, with similar relation to monthly tidal current variation all year round. However, the daily quasi-mineral SPM distribution patterns vary between summer and winter half year. The sunlight is thought to be the origin factor leading to the diurnally vertical motion of the biological features, which might cause the diurnal Sv variation. Unlike in winter half year when tidal current is relatively single driving force of the monthly SPM pattern, the high speed current near the thermocline is also responsible for the concentration of quasi-mineral SPM in summer half year. The sediment input difference between summer and winter half year contribute to the varied daily variation of quasi-mineral SPM with re-suspended SPM ir~ winter and sediments from Yellow Sea Mud Area （YSMA） in summer. The seasonal variations in hydrodynamics, water structure and heavy-wind incidents are the primary factors influencing the differential seasonal SPM distribution patterns.
文摘In this note, we would like to point out that （i） of Corollary 1 given by Zhang et al. （cf Commun. Theor. Phys. 39 （2003） 381） is incorrect in general.
文摘In this paper, we study a delayed SIRS model with nonlocal diffusion. The well posedness of the model is investigated. Furthermore, we concern with the problem of traveling wave solutions. By using the partial quasi-monotone condition, cross-iteration scheme and fixed-point theorem, sufficient conditions are derived for the existence of traveling waves connecting the two equilibria which depends on the existence of a pair of upper solution and lower solution. We in fact construct a pair of upper solution and lower solution concretely to guarantee the existence of traveling waves.
基金supported by the National Natural Science Foundation of China(Grant Nos.52175223,and 11802072)the Fundamental Research Funds for the Central Universities(Grant No.B210201038).
文摘In this work,we propose incorporating the finite cell method(FCM)into the absolute nodal coordinate formulation(ANCF)to improve the efficiency and robustness of ANCF elements in simulating structures with complex local features.In addition,an adaptive subdomain integration method based on a triangulation technique is devised to avoid excessive subdivisions,largely reducing the computational cost.Numerical examples demonstrate the effectiveness of the proposed method in large deformation,large rotation and dynamics simulation.
