With the help of an extended mapping approach and a linear variable separation method,new families ofvariable separation solutions with arbitrary functions for the(3+1)-dimensional Burgers system are derived.Based ont...With the help of an extended mapping approach and a linear variable separation method,new families ofvariable separation solutions with arbitrary functions for the(3+1)-dimensional Burgers system are derived.Based onthe derived exact solutions, some novel and interesting localized coherent excitations such as embed-solitons are revealedby selecting appropriate boundary conditions and/or initial qualifications.The time evolutional properties of the novellocalized excitation are also briefly investigated.展开更多
We propose a catalysis-select migration driven evolution model of two-species(A-and B-species) aggregates,where one unit of species A migrates to species B under the catalysts of species C,while under the catalysts ...We propose a catalysis-select migration driven evolution model of two-species(A-and B-species) aggregates,where one unit of species A migrates to species B under the catalysts of species C,while under the catalysts of species D the reaction will become one unit of species B migrating to species A.Meanwhile the catalyst aggregates of species C perform self-coagulation,as do the species D aggregates.We study this catalysis-select migration driven kinetic aggregation phenomena using the generalized Smoluchowski rate equation approach with C species catalysis-select migration rate kernel K(k;i,j) = Kkij and D species catalysis-select migration rate kernel J(k;i,j) = Jkij.The kinetic evolution behaviour is found to be dominated by the competition between the catalysis-select immigration and emigration,in which the competition is between JD0 and KC0(D0 and C0 are the initial numbers of the monomers of species D and C,respectively).When JD0 KC0 〉 0,the aggregate size distribution of species A satisfies the conventional scaling form and that of species B satisfies a modified scaling form.And in the case of JD0 KC0 〈 0,species A and B exchange their aggregate size distributions as in the above JD0 KC0 〉 0 case.展开更多
The main purpose of this paper is to discuss the existence and asymptotic behavior of solutions for [GRAPHICS] and for which the sufficient conditions of asymptotic behavior are obtained and the restriction for the ex...The main purpose of this paper is to discuss the existence and asymptotic behavior of solutions for [GRAPHICS] and for which the sufficient conditions of asymptotic behavior are obtained and the restriction for the existence is reduced.展开更多
The characteristics of sustainable development problems in the developing countries is discussed.In order to develop and use decision support system (DSS) for supporting sustainable development problem decision making...The characteristics of sustainable development problems in the developing countries is discussed.In order to develop and use decision support system (DSS) for supporting sustainable development problem decision making in the developing countries,this paper presents a strategy of constructing the DSS for sustainable development.A methodology of representing the model of sustainable development problems and developing a nonprocedural modeling language that is used to define sustainable development problems,a methodology of numeric and non numeric operation based theorem proving is given in this paper.展开更多
The anodic layer and oxygen evolution behavior of Pb-Ag-Nd alloy during pulse current polarization and constant current polarization in 160 g/L H2SO4 solution was comparatively investigated by chronopotentiometry, SEM...The anodic layer and oxygen evolution behavior of Pb-Ag-Nd alloy during pulse current polarization and constant current polarization in 160 g/L H2SO4 solution was comparatively investigated by chronopotentiometry, SEM, XRD, EIS and Tafel techniques. The results show that the anodic layer on Pb-Ag-Nd alloy formed through pulse current polarization is more intact and presents fewer micro-holes than that formed through constant current polarization. This could be attributed to the low current density period, which works as a ‘recovery period'. During this period, the oxygen evolution reaction is less intense, which benefits the recovery of porous anodic layer. Pb-Ag-Nd anode also shows a lower anodic potential during pulse current polarization, which is in accordance with its smaller charge transfer resistance and smaller Tafel slope coefficient at high over-potential region. The lower anodic potential could be ascribed to the higher concentration of Pb O2 in the anodic layer, which promotes the formation of more reactive sites for the oxygen evolution reaction.展开更多
Iron carbon agglomerates(ICA)are the composite burden for low-carbon blast furnace(BF)ironmaking.In order to optimize the reactivity of ICA according to the evolution characteristics of ICA in the BF smelting process,...Iron carbon agglomerates(ICA)are the composite burden for low-carbon blast furnace(BF)ironmaking.In order to optimize the reactivity of ICA according to the evolution characteristics of ICA in the BF smelting process,the evolution behavior and mechanism of different reactive ICA under simulated BF smelting conditions were studied.The results show that the existence of more sillimanite and aluminosilicate and less active sites of metallic iron will weaken gasification reaction and carburization ability of ICA-1(containing 10%iron ore).It weakens the promoting effect of ICA-1 on the reduction,softening,and melting of ferrous burdens and the dripping of slag-iron.The aluminosilicate with a high melting point decreases,the low melting point slag phase and Fe–Si alloy increase,and many active sites of metallic iron exist,which strengthen the gasification reaction and carburization ability of ICA-2(containing 30%iron ore).The promoting effect of ICA-2 on the reduction,softening,and melting of ferrous burdens and the dripping of slag-iron is significantly improved.The gasification reaction capacity of ICA-3(containing 35%iron ore)is reduced,and the improvement in ICA-3 on the softening–melting performance of mixed burdens is reduced.The appropriate proportion of iron ore in ICA is about 30%.展开更多
We propose two irreversible aggregation growth models of aggregates of two distinct species (.4 and B) to study the interactions between virus aggregates and medicine efficacy aggregates in the virus-medicine cooper...We propose two irreversible aggregation growth models of aggregates of two distinct species (.4 and B) to study the interactions between virus aggregates and medicine efficacy aggregates in the virus-medicine cooperative evolution system. The A-species aggregates evolve driven by self monomer birth and B-species aggregate-catalyzed monomer death in model I and by self birth, catalyzed death, and self monomer exchange reactions in model II, while the catalyst B-species aggregates are assumed to be injected into the system sustainedly or at a periodic time-dependent rate. The kinetic behaviors of the A-species aggregates are investigated by the rate equation approach based on the mean-field theory with the self birth rate kernel IA(k) = Ik, catalyzed death rate kernel JAB(k) = Jk and self exchange rate kernel KA (k, l) = Kkl. The kinetic behaviors of the A-species aggregates are mainly dominated by the competition between the two effects of the self birth (with the effective rate I) and the catalyzed death (with the effective rate JB0), while the effects of the self exchanges of the A-species aggregates which appear in an effective rate KAo play important roles in the cases of I 〉 JBo and I = JBo. The evolution behaviors of the total mass M1^A(t) and the total aggregate number MA(t) are obtained, and the aggregate size distribution ak(t) of species A is found to approach a generalized scaling form in the case of I ≥ JBo and a special modified scaling form in the case of I 〈 JB0. The periodical evolution of the B-monomers concentration plays an exponential form of the periodic modulation.展开更多
The inclusions evolution behavior in the continuous casting slab, rolled plates, and simulated welding samples of EH36 steels with and without Zr addition has been systematically investigated. The inclusions in plain ...The inclusions evolution behavior in the continuous casting slab, rolled plates, and simulated welding samples of EH36 steels with and without Zr addition has been systematically investigated. The inclusions in plain EH36 steel are almost composed of Al-Ca-S-O(-Mn) and undergo negligible changes during the whole process. With Zr addition, a large amount of individually fine MnS precipitates and Zr-containing inclusions are generated. In the rolled EH36-Zr sample, Zr-containing complex inclusions are effective to promote the nucleation of acicular ferrite on the surface, which are hardly found in the simulated welding sample of EH36-Zr steel due to the segregation of soluble Ti and Zr on the grain boundary.展开更多
To study the damage evolution behavior of polypropylene fiber reinforced concrete(PFRC)subjected to sulfate attack,a uniaxial compression test was carried out based on acoustic emission(AE).The effect of sulfate attac...To study the damage evolution behavior of polypropylene fiber reinforced concrete(PFRC)subjected to sulfate attack,a uniaxial compression test was carried out based on acoustic emission(AE).The effect of sulfate attack relative to time and fiber hybridization were analyzed and the compression damage factor was calculated using a mathematical model.The changes to AE ringing counts during the compression could be divided into compaction,elastic,and AE signal hyperactivity stages.In the initial stage of sulfate attack,the concrete micropores and microcracks were compacted gradually under external load and a corrosion products filling effect,and this corresponded with detection of few AE signals and with concrete compression strength enhancement.With increasing sulfate attack time,AE activity decreased.The cumulative AE ringing counts of PFRC at all corrosion ages were much higher than those for plain concrete.PFRC could still produce AE signals after peak load due to drawing effect of polypropylene fiber.After 150 d of sulfate attack,the cumulative AE ringing counts of plain concrete went down by about an order of magnitude,while that for PFRC remained at a high level.The initial damage factor of hybrid PFRC was-0.042 and-0.056 respectively after 150 d of corrosion,indicating that the advantage of hybrid polypropylene fiber was more obvious than plain concrete and single-doped PFRC.Based on a deterioration equation,the corrosion resistance coefficient of hybrid PFRC would be less than 0.75 after 42 drying-wetting sulfate attack cycles,which was 40%longer than that of plain concrete.展开更多
The production of novel behavioral sequences that gives rise to animal innovation and creativity is one of the most intriguing aspects of behavioral evolution. Numerous studies have recently documented the abundance a...The production of novel behavioral sequences that gives rise to animal innovation and creativity is one of the most intriguing aspects of behavioral evolution. Numerous studies have recently documented the abundance and diversity of innova- tive and creative behaviors between and within species, yet the ability to innovate or to act creatively has mainly been described and quantified as a measure of animals' cognitive ability without explicit reference to cognitive mechanisms that may account for these behaviors. Here we discuss the creative process from a computational point of view and suggest such a mechanistic frame- work. In light of recent research on human creativity, animal learning, and animal problem solving, we suggest that animal crea- tivity is best understood as the production of context-appropriate novel behavioral sequences, which may be facilitated by the ability to learn the regularities in the environment and to represent them hierarchically, allowing for generalization. We present a cognitive framework that we recently developed, which employs domain-general mechanisms and has been used in the modeling of a range of sequential behaviors, from animal foraging to language acquisition, and apply it to behavioral innovation. In a series of simulations, we show how innovation and creative behavior can be produced by this learning mechanism, as it constructs a network representing the statistical regularities of the environment. We use the simulations to demonstrate the role of particular cognitive parameters in this process and to highlight the effects of the learning dynamics and individual experience on creativity展开更多
Habitat structure has been considered as an important factor affecting the acoustic evolution of birds,and bird songs are increasingly affected by artificial environmental variation.Invasive plants sometimes can drama...Habitat structure has been considered as an important factor affecting the acoustic evolution of birds,and bird songs are increasingly affected by artificial environmental variation.Invasive plants sometimes can dramatically alter native habitats,but the song variation of native songbirds migrating into invaded habitats has received little attention.The invasion of smooth cordgrass Spartina alterniflora in the coastal wetlands of eastern China has drastically altered the vegetation structure and some small passerines have begun to use invaded habitats to breed.In this study,we compared the song type prevalence and the song characteristics of male plain prinia Prinia inornata to identify differences in vocal behavior between native and invaded habitats.We also tested for differences in vocal behavior in relation to singing perch and wind speed variation between different habitats.The results indicated that males of plain prinia in invaded habitats sang shorter songs than those in native habitats and had a lower song diversity.The homogeneous vegetation structure and higher wind speed in invaded habitats likely leads to males changing the traditional perched singing style.The song variation may be related to the founder effect,the alteration of vegetation structure and microclimate in invaded habitats.This finding highlights the need for better understanding the behavioral evolution of native species in the process of adapting to the invaded habitat.In the future,experimental manipulation is needed to ascertain how the invasive plant drove these vocal behavior changes of native songbirds.展开更多
The synthesis of high-quality ultrathin overlayers is critically dependent on the surface structure of substrates,especially involving the overlayer–substrate interaction.By using in situ surface measurements,we demo...The synthesis of high-quality ultrathin overlayers is critically dependent on the surface structure of substrates,especially involving the overlayer–substrate interaction.By using in situ surface measurements,we demonstrate that the overlayer–substrate interaction can be tuned by doping near-surface Ar nanobubbles.The interfacial coupling strength significantly decreases with near-surface Ar nanobubbles,accompanying by an“anisotropic to isotropic”growth transformation.On the substrate containing near-surface Ar,the growth front crosses entire surface atomic steps in both uphill and downhill directions with no difference,and thus,the morphology of the two-dimensional(2D)overlayer exhibits a round-shape.Especially,the round-shaped 2D overlayers coalesce seamlessly with a growth acceleration in the approaching direction,which is barely observed in the synthesis of 2D materials.This can be attributed to the immigration lifetime and diffusion rate of growth species,which depends on the overlayer–substrate interaction and the surface catalysis.Furthermore,the“round to hexagon”morphological transition is achieved by etching-regrowth,revealing the inherent growth kinetics under quasi-freestanding conditions.These findings provide a novel promising way to modulate the growth,coalescence,and etching dynamics of 2D materials on solid surfaces by adjusting the strength of overlayer–substrate interaction,which contributes to optimization of large-scale production of 2D material crystals.展开更多
Temporary mining is a peculiar behavioral trait in leaf parasites requiring adaptations of consecutive larval stages to the endophytic and ectophytic life. The first fossil evidence for the origin of the trait comes f...Temporary mining is a peculiar behavioral trait in leaf parasites requiring adaptations of consecutive larval stages to the endophytic and ectophytic life. The first fossil evidence for the origin of the trait comes from the Cretaceous (Turonian) plant-insect locality of the Negev Desert containing rich trace assemblages of leaf parasites, including blotch mines with leaf pieces cut out for case construction, as well as attached larval cases. The host plants are deciduous broadleafs or aquatic angiosperms with emergent leaves, suggesting that initial acquisition of the habit might have been related to leaf abscission and the risk for the larva being chocked in the mine during floods. Unlike tracks of permanent miners, temporary mines never co-occur on leaves with other type mines, which attests to their effect of enhancing plant resistance. Mine predation appears to have been widespread in the Cretaceous biotic community, suggesting a possibility of top-down regulation of mining habits at this early stage of their evolutionary development.展开更多
By introducing the Dzyaloshinsky-Moriya (DM) interaction, the Loschmidt Echo (LE) of a quantum sys- tem consisting of a central spin and its surrounding environment characterized by an XY spin chain was investigat...By introducing the Dzyaloshinsky-Moriya (DM) interaction, the Loschmidt Echo (LE) of a quantum sys- tem consisting of a central spin and its surrounding environment characterized by an XY spin chain was investigated analytically and numerically. At the critical points of the magnetic field, the LE presents an obvious decay. The decay amplitude can be tuned by the DM interaction. In some specific intervals the DM interaction can remarkably delay the decay of the LE. On the other hand, the DM interaction can change the effects of the anisotropy parameter on the LE.展开更多
基金the Natural Science Foundation of Zhejiang Province under Grant Nos. Y604106 and Y606181the Foundation of New Century "151 Talent Engineering" of Zhejiang Province+1 种基金the Scientific Research Foundation of Key Discipline of Zhejiang Provincethe Natural Science Foundation of Zhejiang Lishui University under Grant No KZ06006
文摘With the help of an extended mapping approach and a linear variable separation method,new families ofvariable separation solutions with arbitrary functions for the(3+1)-dimensional Burgers system are derived.Based onthe derived exact solutions, some novel and interesting localized coherent excitations such as embed-solitons are revealedby selecting appropriate boundary conditions and/or initial qualifications.The time evolutional properties of the novellocalized excitation are also briefly investigated.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10875086 and 10775104)
文摘We propose a catalysis-select migration driven evolution model of two-species(A-and B-species) aggregates,where one unit of species A migrates to species B under the catalysts of species C,while under the catalysts of species D the reaction will become one unit of species B migrating to species A.Meanwhile the catalyst aggregates of species C perform self-coagulation,as do the species D aggregates.We study this catalysis-select migration driven kinetic aggregation phenomena using the generalized Smoluchowski rate equation approach with C species catalysis-select migration rate kernel K(k;i,j) = Kkij and D species catalysis-select migration rate kernel J(k;i,j) = Jkij.The kinetic evolution behaviour is found to be dominated by the competition between the catalysis-select immigration and emigration,in which the competition is between JD0 and KC0(D0 and C0 are the initial numbers of the monomers of species D and C,respectively).When JD0 KC0 〉 0,the aggregate size distribution of species A satisfies the conventional scaling form and that of species B satisfies a modified scaling form.And in the case of JD0 KC0 〈 0,species A and B exchange their aggregate size distributions as in the above JD0 KC0 〉 0 case.
文摘The main purpose of this paper is to discuss the existence and asymptotic behavior of solutions for [GRAPHICS] and for which the sufficient conditions of asymptotic behavior are obtained and the restriction for the existence is reduced.
基金the National Natural Science Foundation of China!(No.79990 580 )
文摘The characteristics of sustainable development problems in the developing countries is discussed.In order to develop and use decision support system (DSS) for supporting sustainable development problem decision making in the developing countries,this paper presents a strategy of constructing the DSS for sustainable development.A methodology of representing the model of sustainable development problems and developing a nonprocedural modeling language that is used to define sustainable development problems,a methodology of numeric and non numeric operation based theorem proving is given in this paper.
基金Projects(51204208,51374240)supported by the National Natural Science Foundation of ChinaProject(2012BAA03B04)supported by the National Science and Technology Pillar Program of ChinaProject(2014zzts028)supported by the Fundamental Research Funds for the Central Universities of Central South University,China
文摘The anodic layer and oxygen evolution behavior of Pb-Ag-Nd alloy during pulse current polarization and constant current polarization in 160 g/L H2SO4 solution was comparatively investigated by chronopotentiometry, SEM, XRD, EIS and Tafel techniques. The results show that the anodic layer on Pb-Ag-Nd alloy formed through pulse current polarization is more intact and presents fewer micro-holes than that formed through constant current polarization. This could be attributed to the low current density period, which works as a ‘recovery period'. During this period, the oxygen evolution reaction is less intense, which benefits the recovery of porous anodic layer. Pb-Ag-Nd anode also shows a lower anodic potential during pulse current polarization, which is in accordance with its smaller charge transfer resistance and smaller Tafel slope coefficient at high over-potential region. The lower anodic potential could be ascribed to the higher concentration of Pb O2 in the anodic layer, which promotes the formation of more reactive sites for the oxygen evolution reaction.
基金This work was financially supported by the National Natural Science Foundation of China-Liaoning Joint Funds(U1808212)National Natural Science Foundation of China(52074080)Xingliao Talent Plan(XLYC1902118).
文摘Iron carbon agglomerates(ICA)are the composite burden for low-carbon blast furnace(BF)ironmaking.In order to optimize the reactivity of ICA according to the evolution characteristics of ICA in the BF smelting process,the evolution behavior and mechanism of different reactive ICA under simulated BF smelting conditions were studied.The results show that the existence of more sillimanite and aluminosilicate and less active sites of metallic iron will weaken gasification reaction and carburization ability of ICA-1(containing 10%iron ore).It weakens the promoting effect of ICA-1 on the reduction,softening,and melting of ferrous burdens and the dripping of slag-iron.The aluminosilicate with a high melting point decreases,the low melting point slag phase and Fe–Si alloy increase,and many active sites of metallic iron exist,which strengthen the gasification reaction and carburization ability of ICA-2(containing 30%iron ore).The promoting effect of ICA-2 on the reduction,softening,and melting of ferrous burdens and the dripping of slag-iron is significantly improved.The gasification reaction capacity of ICA-3(containing 35%iron ore)is reduced,and the improvement in ICA-3 on the softening–melting performance of mixed burdens is reduced.The appropriate proportion of iron ore in ICA is about 30%.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10875086 and 10775104
文摘We propose two irreversible aggregation growth models of aggregates of two distinct species (.4 and B) to study the interactions between virus aggregates and medicine efficacy aggregates in the virus-medicine cooperative evolution system. The A-species aggregates evolve driven by self monomer birth and B-species aggregate-catalyzed monomer death in model I and by self birth, catalyzed death, and self monomer exchange reactions in model II, while the catalyst B-species aggregates are assumed to be injected into the system sustainedly or at a periodic time-dependent rate. The kinetic behaviors of the A-species aggregates are investigated by the rate equation approach based on the mean-field theory with the self birth rate kernel IA(k) = Ik, catalyzed death rate kernel JAB(k) = Jk and self exchange rate kernel KA (k, l) = Kkl. The kinetic behaviors of the A-species aggregates are mainly dominated by the competition between the two effects of the self birth (with the effective rate I) and the catalyzed death (with the effective rate JB0), while the effects of the self exchanges of the A-species aggregates which appear in an effective rate KAo play important roles in the cases of I 〉 JBo and I = JBo. The evolution behaviors of the total mass M1^A(t) and the total aggregate number MA(t) are obtained, and the aggregate size distribution ak(t) of species A is found to approach a generalized scaling form in the case of I ≥ JBo and a special modified scaling form in the case of I 〈 JB0. The periodical evolution of the B-monomers concentration plays an exponential form of the periodic modulation.
文摘The inclusions evolution behavior in the continuous casting slab, rolled plates, and simulated welding samples of EH36 steels with and without Zr addition has been systematically investigated. The inclusions in plain EH36 steel are almost composed of Al-Ca-S-O(-Mn) and undergo negligible changes during the whole process. With Zr addition, a large amount of individually fine MnS precipitates and Zr-containing inclusions are generated. In the rolled EH36-Zr sample, Zr-containing complex inclusions are effective to promote the nucleation of acicular ferrite on the surface, which are hardly found in the simulated welding sample of EH36-Zr steel due to the segregation of soluble Ti and Zr on the grain boundary.
基金The support from Mechanical Effect and Safety Analysis of Severely Damaged Tunnel Renovation Process(No.H20210058)is gratefully acknowledged.
文摘To study the damage evolution behavior of polypropylene fiber reinforced concrete(PFRC)subjected to sulfate attack,a uniaxial compression test was carried out based on acoustic emission(AE).The effect of sulfate attack relative to time and fiber hybridization were analyzed and the compression damage factor was calculated using a mathematical model.The changes to AE ringing counts during the compression could be divided into compaction,elastic,and AE signal hyperactivity stages.In the initial stage of sulfate attack,the concrete micropores and microcracks were compacted gradually under external load and a corrosion products filling effect,and this corresponded with detection of few AE signals and with concrete compression strength enhancement.With increasing sulfate attack time,AE activity decreased.The cumulative AE ringing counts of PFRC at all corrosion ages were much higher than those for plain concrete.PFRC could still produce AE signals after peak load due to drawing effect of polypropylene fiber.After 150 d of sulfate attack,the cumulative AE ringing counts of plain concrete went down by about an order of magnitude,while that for PFRC remained at a high level.The initial damage factor of hybrid PFRC was-0.042 and-0.056 respectively after 150 d of corrosion,indicating that the advantage of hybrid polypropylene fiber was more obvious than plain concrete and single-doped PFRC.Based on a deterioration equation,the corrosion resistance coefficient of hybrid PFRC would be less than 0.75 after 42 drying-wetting sulfate attack cycles,which was 40%longer than that of plain concrete.
基金We would like to thank Corina Logan and an anonymous reviewer for their comments, which helped improve this manuscript. OK was partially supported by a Dean's scholarship from the Faculty of Life Sciences at Tel- Aviv University and by a Wolf Foundation award. AL and OK were partially supported by the Israel Science Foundation grant no. 1312/11.
文摘The production of novel behavioral sequences that gives rise to animal innovation and creativity is one of the most intriguing aspects of behavioral evolution. Numerous studies have recently documented the abundance and diversity of innova- tive and creative behaviors between and within species, yet the ability to innovate or to act creatively has mainly been described and quantified as a measure of animals' cognitive ability without explicit reference to cognitive mechanisms that may account for these behaviors. Here we discuss the creative process from a computational point of view and suggest such a mechanistic frame- work. In light of recent research on human creativity, animal learning, and animal problem solving, we suggest that animal crea- tivity is best understood as the production of context-appropriate novel behavioral sequences, which may be facilitated by the ability to learn the regularities in the environment and to represent them hierarchically, allowing for generalization. We present a cognitive framework that we recently developed, which employs domain-general mechanisms and has been used in the modeling of a range of sequential behaviors, from animal foraging to language acquisition, and apply it to behavioral innovation. In a series of simulations, we show how innovation and creative behavior can be produced by this learning mechanism, as it constructs a network representing the statistical regularities of the environment. We use the simulations to demonstrate the role of particular cognitive parameters in this process and to highlight the effects of the learning dynamics and individual experience on creativity
基金funded by the National Natural Science Foundation of China(No.31670432)the Research Culture Funds of Anhui Normal University(No.2020XJ43).
文摘Habitat structure has been considered as an important factor affecting the acoustic evolution of birds,and bird songs are increasingly affected by artificial environmental variation.Invasive plants sometimes can dramatically alter native habitats,but the song variation of native songbirds migrating into invaded habitats has received little attention.The invasion of smooth cordgrass Spartina alterniflora in the coastal wetlands of eastern China has drastically altered the vegetation structure and some small passerines have begun to use invaded habitats to breed.In this study,we compared the song type prevalence and the song characteristics of male plain prinia Prinia inornata to identify differences in vocal behavior between native and invaded habitats.We also tested for differences in vocal behavior in relation to singing perch and wind speed variation between different habitats.The results indicated that males of plain prinia in invaded habitats sang shorter songs than those in native habitats and had a lower song diversity.The homogeneous vegetation structure and higher wind speed in invaded habitats likely leads to males changing the traditional perched singing style.The song variation may be related to the founder effect,the alteration of vegetation structure and microclimate in invaded habitats.This finding highlights the need for better understanding the behavioral evolution of native species in the process of adapting to the invaded habitat.In the future,experimental manipulation is needed to ascertain how the invasive plant drove these vocal behavior changes of native songbirds.
基金the National Natural Science Foundation of China(Nos.21872169,91845109,21688102,and 21825203)the National Key R&D Program of China(No.2016YFA0200200)+2 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB17020000)China Postdoctoral Science Foundation(No.2019M651997)Natural Science Foundation of Jiangsu Province(No.BK20200257).
文摘The synthesis of high-quality ultrathin overlayers is critically dependent on the surface structure of substrates,especially involving the overlayer–substrate interaction.By using in situ surface measurements,we demonstrate that the overlayer–substrate interaction can be tuned by doping near-surface Ar nanobubbles.The interfacial coupling strength significantly decreases with near-surface Ar nanobubbles,accompanying by an“anisotropic to isotropic”growth transformation.On the substrate containing near-surface Ar,the growth front crosses entire surface atomic steps in both uphill and downhill directions with no difference,and thus,the morphology of the two-dimensional(2D)overlayer exhibits a round-shape.Especially,the round-shaped 2D overlayers coalesce seamlessly with a growth acceleration in the approaching direction,which is barely observed in the synthesis of 2D materials.This can be attributed to the immigration lifetime and diffusion rate of growth species,which depends on the overlayer–substrate interaction and the surface catalysis.Furthermore,the“round to hexagon”morphological transition is achieved by etching-regrowth,revealing the inherent growth kinetics under quasi-freestanding conditions.These findings provide a novel promising way to modulate the growth,coalescence,and etching dynamics of 2D materials on solid surfaces by adjusting the strength of overlayer–substrate interaction,which contributes to optimization of large-scale production of 2D material crystals.
文摘Temporary mining is a peculiar behavioral trait in leaf parasites requiring adaptations of consecutive larval stages to the endophytic and ectophytic life. The first fossil evidence for the origin of the trait comes from the Cretaceous (Turonian) plant-insect locality of the Negev Desert containing rich trace assemblages of leaf parasites, including blotch mines with leaf pieces cut out for case construction, as well as attached larval cases. The host plants are deciduous broadleafs or aquatic angiosperms with emergent leaves, suggesting that initial acquisition of the habit might have been related to leaf abscission and the risk for the larva being chocked in the mine during floods. Unlike tracks of permanent miners, temporary mines never co-occur on leaves with other type mines, which attests to their effect of enhancing plant resistance. Mine predation appears to have been widespread in the Cretaceous biotic community, suggesting a possibility of top-down regulation of mining habits at this early stage of their evolutionary development.
基金Supported by Scientific Research Project for Shaanxi Provincial Department of Education(12Jk0957)Science Foundation of Xi’an University of Posts and Telecommunications(1050409,1051206)
文摘By introducing the Dzyaloshinsky-Moriya (DM) interaction, the Loschmidt Echo (LE) of a quantum sys- tem consisting of a central spin and its surrounding environment characterized by an XY spin chain was investigated analytically and numerically. At the critical points of the magnetic field, the LE presents an obvious decay. The decay amplitude can be tuned by the DM interaction. In some specific intervals the DM interaction can remarkably delay the decay of the LE. On the other hand, the DM interaction can change the effects of the anisotropy parameter on the LE.