It would be well to note that in the absence of clear data about the formation of adaptation systems,or mechanisms of their occurrence,all that is recognized is the realization of the micro evolutionary processes.Ther...It would be well to note that in the absence of clear data about the formation of adaptation systems,or mechanisms of their occurrence,all that is recognized is the realization of the micro evolutionary processes.There is no well-defined connection between information exchange and formation展开更多
The northern Guangxi region is an important rare metal, rare earth metal and polymetallic metallogenic province. In the region there exist five metallogenic series and two metallogenic subseries, whose metallogenesis ...The northern Guangxi region is an important rare metal, rare earth metal and polymetallic metallogenic province. In the region there exist five metallogenic series and two metallogenic subseries, whose metallogenesis shows features of polycyclic spiral evolution throughout the geological history. As far as various cycles are concerned, mantle-derived ore substances were reduced while crust-derived ore substances increased from early to late timesfin the whole geological evolutionary history, mantle-derived substances decreased gradually while crust-derived ones increased. Meanwhile ore element associations became more and more varied. In terms of space, mineralization migrated from the old basement outwards, i.e. from west to east during the Precambrian, and from north to south during the Phanerozoic, and again from east to west during the Yanshanian.展开更多
Ancient landslides with platform geomorphology occasionally reactivate,posing serious geohazards.On September 9,2021,persistent heavy rainfall triggered the reactivation of the Dahekou ancient landslide within a gentl...Ancient landslides with platform geomorphology occasionally reactivate,posing serious geohazards.On September 9,2021,persistent heavy rainfall triggered the reactivation of the Dahekou ancient landslide within a gently sloping geomorphology at the core of Zhangjiantan syncline in China's western Qinling-Daba Mountains.This event caused one death,damaged 80 houses,and blocked the Yushui River.This study reconstructs the sliding process of the Dahekou landslide and deciphers the complex landslide initiation mechanisms through field surveys,unmanned aerial vehicle(UAV)imagery analysis,drilling,electrical resistivity tomography(ERT)and small baseline subset–interferometric synthetic aperture radar(SBAS–InSAR)monitoring.We divide the sliding process of the Dahekou landslide into three stages.Two new landslides(#1 and#2)occurred at 18:30 on September 9,2021.Subsequently,the ancient landslide(#3)slid in the 230°direction at approximately 20:30 on September 9,2021,then changed the direction to 170°–240°at 22:30 on the same day,and moved in the direction of 300°at 10:00 the next day.Finally,the reactivated ancient landslide(#3)formed two partially sliding masses,with volumes of approximately 158×10^(4)m^(3)and 160×10~4 m^(3),along the directions of 170°–240°and 300°,respectively,damaging 80 houses and blocking the Yushui River.Field surveys suggest that new landslides#1 and#2 are rock landslides and soil landslides,respectively,with volumes of approximately 230×10^(4)m^(3)and 7.49×10~4 m^(3).Compared with the InSAR data,the new landslide#1 thrust the ancient landslide#3,with an uplift velocity rate of 22.68 mm/a at the rear edge,from September 2020–September 2021.An analysis of drill hole data reveals that the bedding in the landslide area has complex geological conditions,comprising mudstone prone to slipping with different degrees of weathering.Notably,the core of the Zhangjiatan syncline sits on the sliding bedding of the ancient landslide,contributing to a change in the sliding direction.This comprehensive study reveals that the landslide#1 loading and thrusting,the persistent and heavy rainfall,and the complex geological conditions influenced the reactivated ancient landslide.Considering the intricacies of landslide failure mechanisms,we advocate for giving more attention in the future to the zone of potentially slip-prone strata located at the edge of ancient landslides.展开更多
The high safety of aqueous magnesium ion batteries(AMIBs)contrasts with their limited electrochemical performance.To overcome electrolyte-induced parasitic reactions,it is essential to understand the dynamic evolution...The high safety of aqueous magnesium ion batteries(AMIBs)contrasts with their limited electrochemical performance.To overcome electrolyte-induced parasitic reactions,it is essential to understand the dynamic evolution of concentration-dependent metal ion solvation structures(MISSs).This study systematically reveals the solvation structure evolution of MgCl_(2) aqueous solutions across a full concentration range(0-30 M)and its impact on electrochemical properties using molecular dynamics simulations and density functional theory calculations.Results indicate that six characteristic solvation configurations exist,exhibiting a dynamic,concentration-dependent inter-evolution defined as the solvation structure evolutionary processes(SSEP).The four-phase glass transition mechanism in solvation structure evolution is revealed by analyzing the percentage of each type of solvation structure in different concentrations.The study shows that conductivity is directly related to the dynamic transitions of dominant solvation structures,with a shift in the Mg^(2+) coordination mode—from octahedral through pentahedral intermediates to tetrahedral—revealing a concentration-dependent ion transport mechanism.At low concentrations,free-state stochastic diffusion predominates,reaching a maximum conductivity before transitioning to relay transport within a restricted network at high concentrations.Key contributions include:a general strategy for electrolyte design based on the solvation structure evolution process,which quantitatively correlates structural occupancy with migration properties,and the“Concentration Window”regulation model that balances high conductivity with reduced side reactions.These findings clarify the structural origins of anomalous conductivity in highly concentrated electrolytes and establish a mapping between microstructural evolution and macroscopic performance,providing a theoretical basis for engineering high-security electrolytes of AMIBs.展开更多
Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured ...Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured zone in the roadway.This will provide the basis numerical simulation to calculate the surrounding rock fractured zone in a roadway.Using the single factor and multi-factor orthogonal test method,the evolution law of roadway surrounding rock displacements,plastic zone and stress distribution under different conditions is studied.It reveals the roadway surrounding rock burst evolution process,and obtains five kinds of failure modes in deep soft rock roadway.Using the fuzzy mathematics clustering analysis method,the deep soft surrounding rock failure model in Zhujixi mine can be classified and patterns recognized.Compared to the identification results and the results detected by geological radar of surrounding rock loose circle,the reliability of the results of the pattern recognition is verified and lays the foundations for the support design of deep soft rock roadways.展开更多
The types of operation play a key role in facilitating tourism consumption and economic development in a tourism destination. By adopting evolutionary economic geography theory, the paper analyzes the types of operati...The types of operation play a key role in facilitating tourism consumption and economic development in a tourism destination. By adopting evolutionary economic geography theory, the paper analyzes the types of operation in West Lake Scenic Area from 1978 to 2013. First, an evolution process consisting of four stages is underpinned, and they are: the new establishment stage, the preliminary development stage, the speedup development stage, and the stabilized maturity stage. Specifically, the distinct characteristics associated with operation types are compared and evaluated at different stages throughout the process. The evolution trees are introduced to scrutinize types of operation development. The results of evolution trees demonstrate the substantial increase in both numbers and types. Second, by applying GIS spatial analysis, the paper also analyzes the spatial evolution characteristics on the types of operation, and the results unveil the co-existence of centripetal and centrifugal forces: the processes of spatial agglomeration and spatial dispersion. More specifically, we recognize the spatial process includes the emergence of node and concentration(1978–1995), the sparse distribution and intensity reduction(1996–2002), the patchy distribution and spatial agglomeration intensification(2003–2008), the dispersed distribution and core area agglomeration(2009–2013). Lastly, path dependence on resource endowment, government and market innovation, knowledge learning and spillover can reasonably explain the types of operation evolution. In conclusion, the evolutionary economic geography theories provide new theoretical and empirical perspectives for tourism policy analysis. At the same time, our comprehensive evidences impart more comprehensive insights and offer useful managerial and policy implications.展开更多
Deep-seated toppling in the upper reaches of the Lancang River,southwest China involves deformations exceeding 100 m in depth.The slope deformation is initiated by river downcutting and evolves distinctive characteris...Deep-seated toppling in the upper reaches of the Lancang River,southwest China involves deformations exceeding 100 m in depth.The slope deformation is initiated by river downcutting and evolves distinctive characteristics with a depth of river incision.In this study,we propose a system for evaluating the stability of deep-seated toppled slopes in different evolutionary stages.This system contains identification criteria for each evolutionary stage and provides the corresponding stability evaluation methods.Based on the mechanical and kinematic analysis of slope blocks,the specific stage of slope movement can be identified in the field through outcrop mapping,in situ tests,surface displacement monitoring,and adit and borehole explorations.The stability evaluation methods are established based on the limiting equilibrium theory and the strain compatibility between the undisturbed zone and the toppled zone.Finally,several sample slopes in different evolution stages have been investigated to verify the applicability and accuracy of the proposed stability evaluation system.The results indicate that intense tectonic activity and rapid river incision lead to a maximum principal stress ratio exceeding 10 near the slope surface,thus triggering widespread toppling deformations along the river valley.When considering the losses of joint cohesion during the further rotation process,the safety factor of the slope drops by 7%e28%.The self-stabilization of toppling deformation can be recognized by the layer symmetry configuration after the free rotation of the deflected layers.Intensely toppled rock blocks mainly suffer sliding failures beyond the layer symmetry condition.The factor of safety of the K73 rockslide decreased from 1.17 to 0.87 by considering the development of the potential sliding surface and the toesaturated zone.展开更多
In this study,we aim to examine the dynamics of diseases by employing both voluntary and forced control strategies backed by evolutionary game theory(EGT).The impact of quarantine is investigated through our suggested...In this study,we aim to examine the dynamics of diseases by employing both voluntary and forced control strategies backed by evolutionary game theory(EGT).The impact of quarantine is investigated through our suggested framework provided that a partial adoption of voluntary vaccination is observed at the earlier stage.The combined and individual effect of dual preventive provisions are visualized through SEIR-type epidemic model.Additionally,the effect of coercive control policies’efficacy on individual vaccination decision is illustrated through the lens of EGT.We also consider the cost associated with vaccination and quarantine.The numerical simulations shown in our work emphasize how important it is to put quarantine rules in place to stop the spread of infection.These restrictions imposed by the government can be relieving,especially during times when a sizable section of the populace is reluctant to get vaccinated because of its ineffectiveness or excessive cost.We also show when and under what circumstances one policy works better than the other.How these policies’compliance rates should be calculated is therefore becomes a focal point of discussion.We support this claim by producing phase diagrams for three different evolutionary outcomes throughout our investigation and changing the two crucially important pick-up rate parameters,one connected with the quarantine policy and the other is related to the isolation policy,in various directions.We then additionally examine the efficacy and cost associated with different policy adaption.This model effectively high-lights the importance of dual provisional safety in understanding public health issues by using the mean-field approximation technique,which aligns with the well-known imitation protocol known as individual-based risk assessment dynamics.展开更多
As an important part of South China Old Land, the Jiangnan Orogenic Belt plays a significant role in explaining the assembly and the evolution of the Upper Yangtze Block and Cathaysia, as well as the structure and gro...As an important part of South China Old Land, the Jiangnan Orogenic Belt plays a significant role in explaining the assembly and the evolution of the Upper Yangtze Block and Cathaysia, as well as the structure and growth mechanism of continental lithosphere in South China.The Lengjiaxi and the Banxi groups are the base strata of the west section of the Jiangnan Orogenic Belt.Thus, the research of geochronology and tectonic evolution of the Lengjiaxi and the Banxi groups is significant.The maximum sedimentary age of the Lengjiaxi Group is ca.862 Ma, and the minimum is ca.822 Ma.The Zhangjiawan Formation, which is situated in the upper part of the Banxi Group is ca.802 Ma.The Lengjiaxi Group and equivalent strata should thus belong to the Neoproterozoic in age.The Jiangnan Orogenic Belt consisting of the Lengjiaxi and the Banxi groups as important constituents is not a Greenville Orogen Belt（1.3 Ga–1.0 Ga）.The Jiangnan Orogenic Belt is a recyclic orogenic belt, and the prototype basin is a foreland basin with materials derived from the southwest and the sediments belong to the active continental sedimentation.By combining large amounts of dating data of the Lengjiaxi and the Banxi groups as well as equivalent strata, the evolutionary model of the western section of the Jiangnan Orogenic Belt is established as follows： Before 862 Ma, the South China Ocean was subducted beneath the Upper Yangtze Block, while a continental island arc was formed on the side near the Upper Yangtze Block.The South China Ocean was not closed in this period.From 862 Ma to 822 Ma, the Upper Yangtze Block was collided with Cathaysia; and sediments began to be deposited in the foreland basin between the two blocks.The Lengjiaxi Group and equivalent strata were thus formed and the materials might be derived from the recyclic orogenic belt.From 822 Ma to 802 Ma, Cathaysia continued pushing to the Upper Yangtze Block, experienced the Jinning-Sibao Movement（Wuling Movement）; as result, the folded basement of the Jiangnan Orogenic Belt was formed.After 802 Ma, Cathaysia and the Upper Yangtze Block were separated from each other, the Nanhua rift basin was formed and began to receive the sediments of the Banxi Group and equivalent strata.These large amounts of dating data and research results also indicate that before the collision of the Upper Yangtze Block with Cathaysia, materials of the continental crust became less and less from the southwest to the east in the Jiangnan Orogeneic Belt; only island arc and neomagmatic arc were developed in the eastern section.Ocean-continent subduction or continent-continent subduction took place in the western and southern sections, while intra-oceanic subduction occurred in the eastern section.Comprehensive analyses on U-Pb ages and Hf model ages of zircons, the main provenance of the Lengjiaxi Group is Cathaysia.展开更多
As an important branch of human geography, transportation geography has experienced three periods of evolution: foundation, systematization, and rapid development of the discipline. It has gradually become a relativel...As an important branch of human geography, transportation geography has experienced three periods of evolution: foundation, systematization, and rapid development of the discipline. It has gradually become a relatively mature discipline. During the period 1930– 1980, the development of transportation geography consisted mainly of the publication of theoretical texts. During 1980–2000, it gradually became a systematic discipline. Since the start of the 21 st century, transportation geography has focused mainly on exploring the impacts of transportation on socio-economic development. Currently, studies on transportation geography have led to significant developments in a number of areas, including transportation theory, facility distribution and planning, transportation flows and network analysis, evaluation of transport modes, transportation planning, and simulation and assessment of urban transportation. Such studies have also enriched human geography research, provided a wider geographical overview and elucidated the development mechanism of transportation, as well as helped to understand the impacts of transport development on socio-economic systems. Some findings obtained by geographers have been widely used in transportation geography and related fields, including the four basic laws of transportation generation, the hub–spoke mode of transport organization, the subordinating and guiding functions of transportation on socio-economic development, regional transport dominance measures, accessibility measures, and spatial organization of port systems.展开更多
Nepal,a small landlocked country in South Asia,holds about 800 km of Himalayan Mountain range including the Earth's highest mountain.Within such a mountain range in the north and plain lowlands in the south,Nepal ...Nepal,a small landlocked country in South Asia,holds about 800 km of Himalayan Mountain range including the Earth's highest mountain.Within such a mountain range in the north and plain lowlands in the south,Nepal provides a habitat for about 9%of global avian fauna.However,this diversity is underrated because of the lack of enough studies,especially using molecular tools to quantify an-d understand the distribution patterns of diversity.In this study,we reviewed the studies in the last two decades(20002019)that used molecular methods to study the biodiversity in Nepal to examine the ongoing research trend and focus.Although Nepalese Himalaya has many opportunities for cutting-edge molecular research,our results indicated that the rate of genetic/genomic studies is much slower compared to the regional trends.We found that genetic research in Nepal heavily relies on resources from international institutes and that too is mostly limited to research on species monitoring,distribution,and taxonomic validations.Local infrastructures to carry out cutting-edge genomic research in Nepal are still in their infancy and there is a strong need for support from national/international scientists,universities,and governmental agencies to expand such genomic infrastructures in Nepal.We particularly highlight avian fauna as a potential future study system in this region that can be an excellent resource to explore key biological questions such as understanding eco-physiology and molecular basis of organismal persistence to changing environment,evolutionary processes underlying divergence and speciation,or mechanisms of endemism and restrictive distribution of species.展开更多
Evolutionary response analysis of Duffing oscillator using Gaussian equivalent linearization in wavelet based time-frequency frame work is presented here. Cubic （i.e., odd type） non-linearity associated with stiffne...Evolutionary response analysis of Duffing oscillator using Gaussian equivalent linearization in wavelet based time-frequency frame work is presented here. Cubic （i.e., odd type） non-linearity associated with stiffness and damping is modeled. The goal of this research is to develop the mathematical model of an equivalent linear system which is applicable for different non-stationary input processes （i.e., either summation of amplitude modulated stationary orthogonal processes or digitally simulated non-stationary processes）. The instantaneous parameters of the ELTVS （equivalent linear time varying system） are evaluated by minimizing the error between the displacements of non-linear and equivalent linear systems in wavelet domain. For this purpose, three different basis functions （i.e., Mexican Hat, Morlet and a modified form of Littlewood-Paley） are used. The unknown parameters （i.e., natural frequency and damping） of the ELTVS are optimized in stochastic least square sense. Numerical results are presented for different types of input to show the applicability and accuracy of the proposed wavelet based linearization technique.展开更多
文摘It would be well to note that in the absence of clear data about the formation of adaptation systems,or mechanisms of their occurrence,all that is recognized is the realization of the micro evolutionary processes.There is no well-defined connection between information exchange and formation
基金This research was supported by the Chinese Foundation for Development of Geological Science and Technology (Project 49273162)the National Natural Science Foundation of China(Project 49273162)
文摘The northern Guangxi region is an important rare metal, rare earth metal and polymetallic metallogenic province. In the region there exist five metallogenic series and two metallogenic subseries, whose metallogenesis shows features of polycyclic spiral evolution throughout the geological history. As far as various cycles are concerned, mantle-derived ore substances were reduced while crust-derived ore substances increased from early to late timesfin the whole geological evolutionary history, mantle-derived substances decreased gradually while crust-derived ones increased. Meanwhile ore element associations became more and more varied. In terms of space, mineralization migrated from the old basement outwards, i.e. from west to east during the Precambrian, and from north to south during the Phanerozoic, and again from east to west during the Yanshanian.
基金funded by the National Natural Science Foundation of China(Grant No.42077257)。
文摘Ancient landslides with platform geomorphology occasionally reactivate,posing serious geohazards.On September 9,2021,persistent heavy rainfall triggered the reactivation of the Dahekou ancient landslide within a gently sloping geomorphology at the core of Zhangjiantan syncline in China's western Qinling-Daba Mountains.This event caused one death,damaged 80 houses,and blocked the Yushui River.This study reconstructs the sliding process of the Dahekou landslide and deciphers the complex landslide initiation mechanisms through field surveys,unmanned aerial vehicle(UAV)imagery analysis,drilling,electrical resistivity tomography(ERT)and small baseline subset–interferometric synthetic aperture radar(SBAS–InSAR)monitoring.We divide the sliding process of the Dahekou landslide into three stages.Two new landslides(#1 and#2)occurred at 18:30 on September 9,2021.Subsequently,the ancient landslide(#3)slid in the 230°direction at approximately 20:30 on September 9,2021,then changed the direction to 170°–240°at 22:30 on the same day,and moved in the direction of 300°at 10:00 the next day.Finally,the reactivated ancient landslide(#3)formed two partially sliding masses,with volumes of approximately 158×10^(4)m^(3)and 160×10~4 m^(3),along the directions of 170°–240°and 300°,respectively,damaging 80 houses and blocking the Yushui River.Field surveys suggest that new landslides#1 and#2 are rock landslides and soil landslides,respectively,with volumes of approximately 230×10^(4)m^(3)and 7.49×10~4 m^(3).Compared with the InSAR data,the new landslide#1 thrust the ancient landslide#3,with an uplift velocity rate of 22.68 mm/a at the rear edge,from September 2020–September 2021.An analysis of drill hole data reveals that the bedding in the landslide area has complex geological conditions,comprising mudstone prone to slipping with different degrees of weathering.Notably,the core of the Zhangjiatan syncline sits on the sliding bedding of the ancient landslide,contributing to a change in the sliding direction.This comprehensive study reveals that the landslide#1 loading and thrusting,the persistent and heavy rainfall,and the complex geological conditions influenced the reactivated ancient landslide.Considering the intricacies of landslide failure mechanisms,we advocate for giving more attention in the future to the zone of potentially slip-prone strata located at the edge of ancient landslides.
基金supported by the National Natural Science Foundation of China(No.11047164)the National Key Laboratory of Infrared Detection Technologies(No.IRDT-23-S01)the Shanghai Explorer Program(No.24TS1403400)。
文摘The high safety of aqueous magnesium ion batteries(AMIBs)contrasts with their limited electrochemical performance.To overcome electrolyte-induced parasitic reactions,it is essential to understand the dynamic evolution of concentration-dependent metal ion solvation structures(MISSs).This study systematically reveals the solvation structure evolution of MgCl_(2) aqueous solutions across a full concentration range(0-30 M)and its impact on electrochemical properties using molecular dynamics simulations and density functional theory calculations.Results indicate that six characteristic solvation configurations exist,exhibiting a dynamic,concentration-dependent inter-evolution defined as the solvation structure evolutionary processes(SSEP).The four-phase glass transition mechanism in solvation structure evolution is revealed by analyzing the percentage of each type of solvation structure in different concentrations.The study shows that conductivity is directly related to the dynamic transitions of dominant solvation structures,with a shift in the Mg^(2+) coordination mode—from octahedral through pentahedral intermediates to tetrahedral—revealing a concentration-dependent ion transport mechanism.At low concentrations,free-state stochastic diffusion predominates,reaching a maximum conductivity before transitioning to relay transport within a restricted network at high concentrations.Key contributions include:a general strategy for electrolyte design based on the solvation structure evolution process,which quantitatively correlates structural occupancy with migration properties,and the“Concentration Window”regulation model that balances high conductivity with reduced side reactions.These findings clarify the structural origins of anomalous conductivity in highly concentrated electrolytes and establish a mapping between microstructural evolution and macroscopic performance,providing a theoretical basis for engineering high-security electrolytes of AMIBs.
基金provided by the National Natural Science Foundation of China(Nos.51322401,51309222,51323004,51579239 and 51574223)the Opening Project Fund of Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation(No.CDPM2014KF03)+2 种基金the State Key Laboratory for GeoMechanics Opening Project Fund of Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and MitigationDeep Underground Engineering,China University of Mining&Technology(No.SKLGDUEK1305)China Postdoctoral Science Foundation(Nos.2014M551700and 2013M531424)
文摘Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured zone in the roadway.This will provide the basis numerical simulation to calculate the surrounding rock fractured zone in a roadway.Using the single factor and multi-factor orthogonal test method,the evolution law of roadway surrounding rock displacements,plastic zone and stress distribution under different conditions is studied.It reveals the roadway surrounding rock burst evolution process,and obtains five kinds of failure modes in deep soft rock roadway.Using the fuzzy mathematics clustering analysis method,the deep soft surrounding rock failure model in Zhujixi mine can be classified and patterns recognized.Compared to the identification results and the results detected by geological radar of surrounding rock loose circle,the reliability of the results of the pattern recognition is verified and lays the foundations for the support design of deep soft rock roadways.
基金Under the auspices of National Natural Science Foundation of China(No.41230631,41471130)
文摘The types of operation play a key role in facilitating tourism consumption and economic development in a tourism destination. By adopting evolutionary economic geography theory, the paper analyzes the types of operation in West Lake Scenic Area from 1978 to 2013. First, an evolution process consisting of four stages is underpinned, and they are: the new establishment stage, the preliminary development stage, the speedup development stage, and the stabilized maturity stage. Specifically, the distinct characteristics associated with operation types are compared and evaluated at different stages throughout the process. The evolution trees are introduced to scrutinize types of operation development. The results of evolution trees demonstrate the substantial increase in both numbers and types. Second, by applying GIS spatial analysis, the paper also analyzes the spatial evolution characteristics on the types of operation, and the results unveil the co-existence of centripetal and centrifugal forces: the processes of spatial agglomeration and spatial dispersion. More specifically, we recognize the spatial process includes the emergence of node and concentration(1978–1995), the sparse distribution and intensity reduction(1996–2002), the patchy distribution and spatial agglomeration intensification(2003–2008), the dispersed distribution and core area agglomeration(2009–2013). Lastly, path dependence on resource endowment, government and market innovation, knowledge learning and spillover can reasonably explain the types of operation evolution. In conclusion, the evolutionary economic geography theories provide new theoretical and empirical perspectives for tourism policy analysis. At the same time, our comprehensive evidences impart more comprehensive insights and offer useful managerial and policy implications.
基金supported by the National Natural Science Foundation of China(Grant Nos.42307220 and 42090055)the Postdoctoral Research Project Funding of Shaanxi Province(Grant No.2023BSHEDZZ210).
文摘Deep-seated toppling in the upper reaches of the Lancang River,southwest China involves deformations exceeding 100 m in depth.The slope deformation is initiated by river downcutting and evolves distinctive characteristics with a depth of river incision.In this study,we propose a system for evaluating the stability of deep-seated toppled slopes in different evolutionary stages.This system contains identification criteria for each evolutionary stage and provides the corresponding stability evaluation methods.Based on the mechanical and kinematic analysis of slope blocks,the specific stage of slope movement can be identified in the field through outcrop mapping,in situ tests,surface displacement monitoring,and adit and borehole explorations.The stability evaluation methods are established based on the limiting equilibrium theory and the strain compatibility between the undisturbed zone and the toppled zone.Finally,several sample slopes in different evolution stages have been investigated to verify the applicability and accuracy of the proposed stability evaluation system.The results indicate that intense tectonic activity and rapid river incision lead to a maximum principal stress ratio exceeding 10 near the slope surface,thus triggering widespread toppling deformations along the river valley.When considering the losses of joint cohesion during the further rotation process,the safety factor of the slope drops by 7%e28%.The self-stabilization of toppling deformation can be recognized by the layer symmetry configuration after the free rotation of the deflected layers.Intensely toppled rock blocks mainly suffer sliding failures beyond the layer symmetry condition.The factor of safety of the K73 rockslide decreased from 1.17 to 0.87 by considering the development of the potential sliding surface and the toesaturated zone.
基金supported by a Grant-in-Aid for Scientific Research from JSPS,Japan,KAKENHI(Grant No.JP 23H03499)awarded to Professor Tanimoto.
文摘In this study,we aim to examine the dynamics of diseases by employing both voluntary and forced control strategies backed by evolutionary game theory(EGT).The impact of quarantine is investigated through our suggested framework provided that a partial adoption of voluntary vaccination is observed at the earlier stage.The combined and individual effect of dual preventive provisions are visualized through SEIR-type epidemic model.Additionally,the effect of coercive control policies’efficacy on individual vaccination decision is illustrated through the lens of EGT.We also consider the cost associated with vaccination and quarantine.The numerical simulations shown in our work emphasize how important it is to put quarantine rules in place to stop the spread of infection.These restrictions imposed by the government can be relieving,especially during times when a sizable section of the populace is reluctant to get vaccinated because of its ineffectiveness or excessive cost.We also show when and under what circumstances one policy works better than the other.How these policies’compliance rates should be calculated is therefore becomes a focal point of discussion.We support this claim by producing phase diagrams for three different evolutionary outcomes throughout our investigation and changing the two crucially important pick-up rate parameters,one connected with the quarantine policy and the other is related to the isolation policy,in various directions.We then additionally examine the efficacy and cost associated with different policy adaption.This model effectively high-lights the importance of dual provisional safety in understanding public health issues by using the mean-field approximation technique,which aligns with the well-known imitation protocol known as individual-based risk assessment dynamics.
基金supported by National Major Projects of Oil and Gas (2011ZX05043-005)Geological Survey Project of China Geological Survey (1212011120115, 1212011120117 and 121201011120131)Natural Science Fund Project (40921062)
文摘As an important part of South China Old Land, the Jiangnan Orogenic Belt plays a significant role in explaining the assembly and the evolution of the Upper Yangtze Block and Cathaysia, as well as the structure and growth mechanism of continental lithosphere in South China.The Lengjiaxi and the Banxi groups are the base strata of the west section of the Jiangnan Orogenic Belt.Thus, the research of geochronology and tectonic evolution of the Lengjiaxi and the Banxi groups is significant.The maximum sedimentary age of the Lengjiaxi Group is ca.862 Ma, and the minimum is ca.822 Ma.The Zhangjiawan Formation, which is situated in the upper part of the Banxi Group is ca.802 Ma.The Lengjiaxi Group and equivalent strata should thus belong to the Neoproterozoic in age.The Jiangnan Orogenic Belt consisting of the Lengjiaxi and the Banxi groups as important constituents is not a Greenville Orogen Belt（1.3 Ga–1.0 Ga）.The Jiangnan Orogenic Belt is a recyclic orogenic belt, and the prototype basin is a foreland basin with materials derived from the southwest and the sediments belong to the active continental sedimentation.By combining large amounts of dating data of the Lengjiaxi and the Banxi groups as well as equivalent strata, the evolutionary model of the western section of the Jiangnan Orogenic Belt is established as follows： Before 862 Ma, the South China Ocean was subducted beneath the Upper Yangtze Block, while a continental island arc was formed on the side near the Upper Yangtze Block.The South China Ocean was not closed in this period.From 862 Ma to 822 Ma, the Upper Yangtze Block was collided with Cathaysia; and sediments began to be deposited in the foreland basin between the two blocks.The Lengjiaxi Group and equivalent strata were thus formed and the materials might be derived from the recyclic orogenic belt.From 822 Ma to 802 Ma, Cathaysia continued pushing to the Upper Yangtze Block, experienced the Jinning-Sibao Movement（Wuling Movement）; as result, the folded basement of the Jiangnan Orogenic Belt was formed.After 802 Ma, Cathaysia and the Upper Yangtze Block were separated from each other, the Nanhua rift basin was formed and began to receive the sediments of the Banxi Group and equivalent strata.These large amounts of dating data and research results also indicate that before the collision of the Upper Yangtze Block with Cathaysia, materials of the continental crust became less and less from the southwest to the east in the Jiangnan Orogeneic Belt; only island arc and neomagmatic arc were developed in the eastern section.Ocean-continent subduction or continent-continent subduction took place in the western and southern sections, while intra-oceanic subduction occurred in the eastern section.Comprehensive analyses on U-Pb ages and Hf model ages of zircons, the main provenance of the Lengjiaxi Group is Cathaysia.
基金National Natural Science Foundation of China,No.41171107No.41371143
文摘As an important branch of human geography, transportation geography has experienced three periods of evolution: foundation, systematization, and rapid development of the discipline. It has gradually become a relatively mature discipline. During the period 1930– 1980, the development of transportation geography consisted mainly of the publication of theoretical texts. During 1980–2000, it gradually became a systematic discipline. Since the start of the 21 st century, transportation geography has focused mainly on exploring the impacts of transportation on socio-economic development. Currently, studies on transportation geography have led to significant developments in a number of areas, including transportation theory, facility distribution and planning, transportation flows and network analysis, evaluation of transport modes, transportation planning, and simulation and assessment of urban transportation. Such studies have also enriched human geography research, provided a wider geographical overview and elucidated the development mechanism of transportation, as well as helped to understand the impacts of transport development on socio-economic systems. Some findings obtained by geographers have been widely used in transportation geography and related fields, including the four basic laws of transportation generation, the hub–spoke mode of transport organization, the subordinating and guiding functions of transportation on socio-economic development, regional transport dominance measures, accessibility measures, and spatial organization of port systems.
基金supported in part by the Department of Biological Sciences。
文摘Nepal,a small landlocked country in South Asia,holds about 800 km of Himalayan Mountain range including the Earth's highest mountain.Within such a mountain range in the north and plain lowlands in the south,Nepal provides a habitat for about 9%of global avian fauna.However,this diversity is underrated because of the lack of enough studies,especially using molecular tools to quantify an-d understand the distribution patterns of diversity.In this study,we reviewed the studies in the last two decades(20002019)that used molecular methods to study the biodiversity in Nepal to examine the ongoing research trend and focus.Although Nepalese Himalaya has many opportunities for cutting-edge molecular research,our results indicated that the rate of genetic/genomic studies is much slower compared to the regional trends.We found that genetic research in Nepal heavily relies on resources from international institutes and that too is mostly limited to research on species monitoring,distribution,and taxonomic validations.Local infrastructures to carry out cutting-edge genomic research in Nepal are still in their infancy and there is a strong need for support from national/international scientists,universities,and governmental agencies to expand such genomic infrastructures in Nepal.We particularly highlight avian fauna as a potential future study system in this region that can be an excellent resource to explore key biological questions such as understanding eco-physiology and molecular basis of organismal persistence to changing environment,evolutionary processes underlying divergence and speciation,or mechanisms of endemism and restrictive distribution of species.
文摘Evolutionary response analysis of Duffing oscillator using Gaussian equivalent linearization in wavelet based time-frequency frame work is presented here. Cubic （i.e., odd type） non-linearity associated with stiffness and damping is modeled. The goal of this research is to develop the mathematical model of an equivalent linear system which is applicable for different non-stationary input processes （i.e., either summation of amplitude modulated stationary orthogonal processes or digitally simulated non-stationary processes）. The instantaneous parameters of the ELTVS （equivalent linear time varying system） are evaluated by minimizing the error between the displacements of non-linear and equivalent linear systems in wavelet domain. For this purpose, three different basis functions （i.e., Mexican Hat, Morlet and a modified form of Littlewood-Paley） are used. The unknown parameters （i.e., natural frequency and damping） of the ELTVS are optimized in stochastic least square sense. Numerical results are presented for different types of input to show the applicability and accuracy of the proposed wavelet based linearization technique.
