The complicated structure of electronic devices makes the conventional annealing method,which involves placing the entire device in a furnace,insufficient for achieving the desired quality.This issue is currently addr...The complicated structure of electronic devices makes the conventional annealing method,which involves placing the entire device in a furnace,insufficient for achieving the desired quality.This issue is currently addressed through the use of pulsed laser annealing,where a specific target layer is heated,preventing the overheating of other layers or the substrate.However,this method is only applicable to a very limited range of materials and requires very expensive,powerful pulsed laser sources.Herein,a novel approach for the selective local thermal treatment of thin films is proposed;in this method,short,powerful current pulses are applied to the target conductive layer.The application of two current pulses with a length of 1.5 s induced the crystallization of a 160-nm thick indium tin oxide(ITO)film,resulting in a sheet resistance of 8.68Ω·sq^(-1),an average visible light transmittance of 86.69%,and a figure of merit(FoM)of 293.61.This FoM is an order of magnitude higher than that of the as-prepared ITO film,and to the best of our knowledge,is among the highest reported values for the polycrystalline ITO films.Simulations have shown that even faster and more localized crystallization could be achieved by increasing the power of pulsed current.This novel annealing method is applicable to most semi-conductive or metallic thin films and requires only a relatively inexpensive pulsed current source,making it potentially more attractive than pulsed laser annealing.展开更多
In particle-filled polymer composites with selective distributions of fillers in one phase,much attention has been focused on the“volume exclusion effect”in reducing the percolation threshold of filler,while the rol...In particle-filled polymer composites with selective distributions of fillers in one phase,much attention has been focused on the“volume exclusion effect”in reducing the percolation threshold of filler,while the role of dispersed polymer phase acting as bridges of fillers in the particle network has largely been ignored.Herein,we studied industrially important ternary composites,polypropylene(PP)/ethylene-octene copolymer(a polyolefin elastomer,POE)/talc systems,and adopted rheology to reveal the bridging behavior of POE droplets in the network of talc particles.It is found that talc fillers concentrate in the PP phase using the“blend first”protocol,while more talc particles are located at the interface of PP and POE phases using the“filler first”protocol.Changing the POE viscosity and talc size can affect the migration of talc from the POE phase to the PP phase in the“filler first”protocol.The linear rheology behavior indicates that besides the“volume exclusion effect”,the talc-POE hybrid network can further contribute to the reinforcement effect.Meanwhile,the POE droplet bridging structure can facilitate the rebuilding of the hybrid network after large amplitude oscillatory shear,in contrast to the un-recoverable structures in the PP/talc binary composites.The correlation between rheology and selective distribution of fillers in ternary composites may provide practical guidance for processing and designing advanced polymer composites with controlled selective location of fillers.展开更多
This study focuses on the problem of multitarget tracking.To address the existing problems of current tracking algorithms,as manifested by the time consumption of subgroup separation and the uneven group size of unman...This study focuses on the problem of multitarget tracking.To address the existing problems of current tracking algorithms,as manifested by the time consumption of subgroup separation and the uneven group size of unmanned aerial vehicles(UAVs)for target tracking,a multitarget tracking control algorithm under local information selection interaction is proposed.First,on the basis of location,number,and perceived target information of neighboring UAVs,a temporary leader selection strategy is designed to realize the local follow-up movement of UAVs when the UAVs cannot fully perceive the target.Second,in combination with the basic rules of cluster movement and target information perception factors,distributed control equations are designed to achieve a rapid gathering of UAVs and consistent tracking of multiple targets.Lastly,the simulation experiments are conducted in two-and three-dimensional spaces.Under a certain number of UAVs,clustering speed of the proposed algorithm is less than 3 s,and the equal probability of the UAV subgroup size after group separation is over 78%.展开更多
In this paper,we propose an Unsupervised Nonlinear Adaptive Manifold Learning method(UNAML)that considers both global and local information.In this approach,we apply unlabeled training samples to study nonlinear manif...In this paper,we propose an Unsupervised Nonlinear Adaptive Manifold Learning method(UNAML)that considers both global and local information.In this approach,we apply unlabeled training samples to study nonlinear manifold features,while considering global pairwise distances and maintaining local topology structure.Our method aims at minimizing global pairwise data distance errors as well as local structural errors.In order to enable our UNAML to be more efficient and to extract manifold features from the external source of new data,we add a feature approximate error that can be used to learn a linear extractor.Also,we add a feature approximate error that can be used to learn a linear extractor.In addition,we use a method of adaptive neighbor selection to calculate local structural errors.This paper uses the kernel matrix method to optimize the original algorithm.Our algorithm proves to be more effective when compared with the experimental results of other feature extraction methods on real face-data sets and object data sets.展开更多
Background Dispersal limitations vary among species within the same region.For some species,geographic distance is the primary constraint,while for others,environmental factors such as climate and vegetation patterns ...Background Dispersal limitations vary among species within the same region.For some species,geographic distance is the primary constraint,while for others,environmental factors such as climate and vegetation patterns play a larger role.These landscape-driven effects are shaped by species-specific ecological traits.Despite being conceptually intuitive,landscape genetics hypotheses—such as Isolation by Distance and Isolation by Environment—remain largely underexplored in tropical regions.We conducted a comparative landscape genetics study to assess the influence of geographic and environmental landscape features on genetic differentiation in two ecologically distinct anurans species:Dendropsophus oliveirai,a diminutive treefrog that uses ponds for reproduction and larval development,and Physalaemus cuvieri,a terrestrial frog that breeds in both ponds and rain pools,depositing eggs in foam nests where embryos develop.These species co-occur in highland forest enclaves within a dry vegetation matrix across the Borborema Plateau,northeastern Brazil.Methods We sampled individuals of both species in seven highland forest enclaves to assess phylogeographic patterns and genetic variation along the steep NE-SW climatic and vegetation gradient characterizing the plateau.Additionally,we collected geographic,climatic,and vegetation data for each site.We analyzed the relationships between geographic distance,environmental variation,climatic variation,and mt DNA genetic differentiation in both species using Mantel tests and Structural Equation Modeling.Results We found lower genetic differentiation in P.cuvieri,which was primarily associated with the geographic distance among enclaves,with only weak influence of environmental variation among sampling sites.Conversely,higher genetic differentiation was detected among geographic populations of D.oliveirai,mainly driven by a combination of geographic distance,environmental heterogeneity,and past climatic variation.Conclusions The contrasting genetic structures of the two species likely result from differences in their ability to traverse dry lowland areas between mesic highland forests,with Isolation by Distance and Isolation by Environment affecting each species differently.These findings suggest that both selective and neutral mechanisms contribute to genetic variation.Our study highlights that highland forests in northeastern Brazil may harbor genetically distinct anuran populations,where gene flow is constrained not only by geographic distance but also by environmental factors,especially in diminutive species with specific reproductive needs.展开更多
基金supported by the National Key R&D Program of China(No.2021YFB2801600)the National Natural Science Foundation of China(Nos.52072060,52202164 and 52021001)the Natural Science Foundation of Sichuan(Nos.2023NSFSC1950 and 2022NSFSC1990).
文摘The complicated structure of electronic devices makes the conventional annealing method,which involves placing the entire device in a furnace,insufficient for achieving the desired quality.This issue is currently addressed through the use of pulsed laser annealing,where a specific target layer is heated,preventing the overheating of other layers or the substrate.However,this method is only applicable to a very limited range of materials and requires very expensive,powerful pulsed laser sources.Herein,a novel approach for the selective local thermal treatment of thin films is proposed;in this method,short,powerful current pulses are applied to the target conductive layer.The application of two current pulses with a length of 1.5 s induced the crystallization of a 160-nm thick indium tin oxide(ITO)film,resulting in a sheet resistance of 8.68Ω·sq^(-1),an average visible light transmittance of 86.69%,and a figure of merit(FoM)of 293.61.This FoM is an order of magnitude higher than that of the as-prepared ITO film,and to the best of our knowledge,is among the highest reported values for the polycrystalline ITO films.Simulations have shown that even faster and more localized crystallization could be achieved by increasing the power of pulsed current.This novel annealing method is applicable to most semi-conductive or metallic thin films and requires only a relatively inexpensive pulsed current source,making it potentially more attractive than pulsed laser annealing.
基金This work was financially supported by the National Natural Science Foundation of China(No.22341303)forms part of the research program of DPI,project#841.
文摘In particle-filled polymer composites with selective distributions of fillers in one phase,much attention has been focused on the“volume exclusion effect”in reducing the percolation threshold of filler,while the role of dispersed polymer phase acting as bridges of fillers in the particle network has largely been ignored.Herein,we studied industrially important ternary composites,polypropylene(PP)/ethylene-octene copolymer(a polyolefin elastomer,POE)/talc systems,and adopted rheology to reveal the bridging behavior of POE droplets in the network of talc particles.It is found that talc fillers concentrate in the PP phase using the“blend first”protocol,while more talc particles are located at the interface of PP and POE phases using the“filler first”protocol.Changing the POE viscosity and talc size can affect the migration of talc from the POE phase to the PP phase in the“filler first”protocol.The linear rheology behavior indicates that besides the“volume exclusion effect”,the talc-POE hybrid network can further contribute to the reinforcement effect.Meanwhile,the POE droplet bridging structure can facilitate the rebuilding of the hybrid network after large amplitude oscillatory shear,in contrast to the un-recoverable structures in the PP/talc binary composites.The correlation between rheology and selective distribution of fillers in ternary composites may provide practical guidance for processing and designing advanced polymer composites with controlled selective location of fillers.
文摘This study focuses on the problem of multitarget tracking.To address the existing problems of current tracking algorithms,as manifested by the time consumption of subgroup separation and the uneven group size of unmanned aerial vehicles(UAVs)for target tracking,a multitarget tracking control algorithm under local information selection interaction is proposed.First,on the basis of location,number,and perceived target information of neighboring UAVs,a temporary leader selection strategy is designed to realize the local follow-up movement of UAVs when the UAVs cannot fully perceive the target.Second,in combination with the basic rules of cluster movement and target information perception factors,distributed control equations are designed to achieve a rapid gathering of UAVs and consistent tracking of multiple targets.Lastly,the simulation experiments are conducted in two-and three-dimensional spaces.Under a certain number of UAVs,clustering speed of the proposed algorithm is less than 3 s,and the equal probability of the UAV subgroup size after group separation is over 78%.
基金supported in part by the National Natural Science Foundation of China(Nos.61373093,61402310,61672364,and 61672365)the National Key Research and Development Program of China(No.2018YFA0701701)。
文摘In this paper,we propose an Unsupervised Nonlinear Adaptive Manifold Learning method(UNAML)that considers both global and local information.In this approach,we apply unlabeled training samples to study nonlinear manifold features,while considering global pairwise distances and maintaining local topology structure.Our method aims at minimizing global pairwise data distance errors as well as local structural errors.In order to enable our UNAML to be more efficient and to extract manifold features from the external source of new data,we add a feature approximate error that can be used to learn a linear extractor.Also,we add a feature approximate error that can be used to learn a linear extractor.In addition,we use a method of adaptive neighbor selection to calculate local structural errors.This paper uses the kernel matrix method to optimize the original algorithm.Our algorithm proves to be more effective when compared with the experimental results of other feature extraction methods on real face-data sets and object data sets.
基金supported by a PhD scholarship by the ProEx Program of the Brazilian Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPESprocess#[88887.485655/2020-00])by an internationalization program(Edital CAPES/Pr Int-Grant#88887.837475/2023-00)
文摘Background Dispersal limitations vary among species within the same region.For some species,geographic distance is the primary constraint,while for others,environmental factors such as climate and vegetation patterns play a larger role.These landscape-driven effects are shaped by species-specific ecological traits.Despite being conceptually intuitive,landscape genetics hypotheses—such as Isolation by Distance and Isolation by Environment—remain largely underexplored in tropical regions.We conducted a comparative landscape genetics study to assess the influence of geographic and environmental landscape features on genetic differentiation in two ecologically distinct anurans species:Dendropsophus oliveirai,a diminutive treefrog that uses ponds for reproduction and larval development,and Physalaemus cuvieri,a terrestrial frog that breeds in both ponds and rain pools,depositing eggs in foam nests where embryos develop.These species co-occur in highland forest enclaves within a dry vegetation matrix across the Borborema Plateau,northeastern Brazil.Methods We sampled individuals of both species in seven highland forest enclaves to assess phylogeographic patterns and genetic variation along the steep NE-SW climatic and vegetation gradient characterizing the plateau.Additionally,we collected geographic,climatic,and vegetation data for each site.We analyzed the relationships between geographic distance,environmental variation,climatic variation,and mt DNA genetic differentiation in both species using Mantel tests and Structural Equation Modeling.Results We found lower genetic differentiation in P.cuvieri,which was primarily associated with the geographic distance among enclaves,with only weak influence of environmental variation among sampling sites.Conversely,higher genetic differentiation was detected among geographic populations of D.oliveirai,mainly driven by a combination of geographic distance,environmental heterogeneity,and past climatic variation.Conclusions The contrasting genetic structures of the two species likely result from differences in their ability to traverse dry lowland areas between mesic highland forests,with Isolation by Distance and Isolation by Environment affecting each species differently.These findings suggest that both selective and neutral mechanisms contribute to genetic variation.Our study highlights that highland forests in northeastern Brazil may harbor genetically distinct anuran populations,where gene flow is constrained not only by geographic distance but also by environmental factors,especially in diminutive species with specific reproductive needs.
