Migratory divides,where individuals from distinct breeding populations within a species exhibit divergent migratory routes and strategies,play a critical role in shaping avian ecology and evolution.These divides can d...Migratory divides,where individuals from distinct breeding populations within a species exhibit divergent migratory routes and strategies,play a critical role in shaping avian ecology and evolution.These divides can drive intraspecific genetic divergence and promote reproductive isolation,potentially leading to population differentiation and speciation.Understanding the migration strategies of populations utilizing distinct flyways is essential not only for elucidating the mechanisms underlying migration patterns but also for informing effective species conservation efforts.From 2014 to 2023,we used satellite tracking to monitor the migration patterns of 87 White-naped Cranes(Antigone vipio)from the species'two breeding populations—western(Mongolia)and eastern(Songnen Plain,China).We delineated their migratory routes,quantified key migration parameters,and identified their population-and season-specific differences in migratory strategies.Our results indicate that the Greater Khingan Mountains and the Bohai-Yellow Sea formed a distinct migratory barrier separating the eastern and western populations.Significant differences in migration strategies were observed between populations and seasons.The western population adopts a"longer-distance,slower-speed,more-stopover"strategy,while the eastern population employs a"shorter-distance,higher-speed,fewer-stopover"strategy.Our study identifies the migratory divides between the two populations of White-naped Cranes and highlights the importance of migratory divides in shaping distinct migration strategies.These findings enhance our understanding of the factors driving population-specific migration strategies and provide a foundation for tailored conservation efforts for these populations.展开更多
The inertial navigation system(INS),which is frequently used in emergency rescue operations and other situations,has the benefits of not relying on infrastructure,high positioning frequency,and strong real-time perfor...The inertial navigation system(INS),which is frequently used in emergency rescue operations and other situations,has the benefits of not relying on infrastructure,high positioning frequency,and strong real-time performance.However,the intricate and unpredictable pedestrian motion patterns lead the INS localization error to significantly diverge with time.This paper aims to enhance the accuracy of zero-velocity interval(ZVI)detection and reduce the heading and altitude drift of foot-mounted INS via deep learning and equation constraint of dual feet.Aiming at the observational noise problem of low-cost inertial sensors,we utilize a denoising autoencoder to automatically eliminate the inherent noise.Aiming at the problem that inaccurate detection of the ZVI detection results in obvious displacement error,we propose a sample-level ZVI detection algorithm based on the U-Net neural network,which effectively solves the problem of mislabeling caused by sliding windows.Aiming at the problem that Zero-Velocity Update(ZUPT)cannot suppress heading and altitude error,we propose a bipedal INS method based on the equation constraint and ellipsoid constraint,which uses foot-to-foot distance as a new observation to correct heading and altitude error.We conduct extensive and well-designed experiments to evaluate the performance of the proposed method.The experimental results indicate that the position error of our proposed method did not exceed 0.83% of the total traveled distance.展开更多
Thermoelectric superlattices are expected to decouple the strong correlation between various thermo-electric parameters,and are an important strategy for excellent thermoelectric performances.The superlattices of(Bi_(...Thermoelectric superlattices are expected to decouple the strong correlation between various thermo-electric parameters,and are an important strategy for excellent thermoelectric performances.The superlattices of(Bi_(2))m(Bi_(2)Te_(3))n homologous series are well-known for low lattice thermal conductivity and intriguing topological surface states.However,the impacts of electronic structure on the thermo-electric performance were still not well-understood in(Bi_(2))m(Bi_(2)Te_(3))n.To cope with this issue,Bi_(2)eBi_(2)Te_(3)superlattice-like films with adjustable Bi_(2)/(Bi_(2)+Bi_(2)Te_(3))molar ratio(R)were successfully fabricated by the molecular beam epitaxy technique.Angle-resolved photoemission spectroscopy measurements com-bined with theoretical calculations revealed the conduction band evolution from single-valley to multi-valley as R≥0.30,leading to intrinsically high carrier effective mass and improved thermoelectric power factor.Also,the superlattice film(R=0.46)with the structure close to Bi_(4)Te_(3)possesses the topological surface state feature around the high symmetry point.As a result of the high effective mass of 3.9 m0 and very high electron density of_(2).31×10^(21)cm^(-3),the film with R=0.46 acquired the highest power factor of 1.49 mW·m^(-1)·K^(-2)at 420 K,outperforming that of other(Bi_(2))m(Bi_(2)Te_(3))n superlattices.This work lays an essential foundation on understanding the electronic structure and further improving thermoelectric performances of(Bi_(2))m(Bi_(2)Te_(3))n homologous series.展开更多
基金supported by the National Natural Science Foundation of China(No.31770573)。
文摘Migratory divides,where individuals from distinct breeding populations within a species exhibit divergent migratory routes and strategies,play a critical role in shaping avian ecology and evolution.These divides can drive intraspecific genetic divergence and promote reproductive isolation,potentially leading to population differentiation and speciation.Understanding the migration strategies of populations utilizing distinct flyways is essential not only for elucidating the mechanisms underlying migration patterns but also for informing effective species conservation efforts.From 2014 to 2023,we used satellite tracking to monitor the migration patterns of 87 White-naped Cranes(Antigone vipio)from the species'two breeding populations—western(Mongolia)and eastern(Songnen Plain,China).We delineated their migratory routes,quantified key migration parameters,and identified their population-and season-specific differences in migratory strategies.Our results indicate that the Greater Khingan Mountains and the Bohai-Yellow Sea formed a distinct migratory barrier separating the eastern and western populations.Significant differences in migration strategies were observed between populations and seasons.The western population adopts a"longer-distance,slower-speed,more-stopover"strategy,while the eastern population employs a"shorter-distance,higher-speed,fewer-stopover"strategy.Our study identifies the migratory divides between the two populations of White-naped Cranes and highlights the importance of migratory divides in shaping distinct migration strategies.These findings enhance our understanding of the factors driving population-specific migration strategies and provide a foundation for tailored conservation efforts for these populations.
基金supported in part by National Key Research and Development Program under Grant No.2020YFB1708800China Postdoctoral Science Foundation under Grant No.2021M700385+5 种基金Guang Dong Basic and Applied Basic Research Foundation under Grant No.2021A1515110577Guangdong Key Research and Development Program under Grant No.2020B0101130007Central Guidance on Local Science and Technology Development Fund of Shanxi Province under Grant No.YDZJSX2022B019Fundamental Research Funds for Central Universities under Grant No.FRF-MP-20-37Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities)under Grant No.FRF-IDRY-21-005National Natural Science Foundation of China under Grant No.62002026。
文摘The inertial navigation system(INS),which is frequently used in emergency rescue operations and other situations,has the benefits of not relying on infrastructure,high positioning frequency,and strong real-time performance.However,the intricate and unpredictable pedestrian motion patterns lead the INS localization error to significantly diverge with time.This paper aims to enhance the accuracy of zero-velocity interval(ZVI)detection and reduce the heading and altitude drift of foot-mounted INS via deep learning and equation constraint of dual feet.Aiming at the observational noise problem of low-cost inertial sensors,we utilize a denoising autoencoder to automatically eliminate the inherent noise.Aiming at the problem that inaccurate detection of the ZVI detection results in obvious displacement error,we propose a sample-level ZVI detection algorithm based on the U-Net neural network,which effectively solves the problem of mislabeling caused by sliding windows.Aiming at the problem that Zero-Velocity Update(ZUPT)cannot suppress heading and altitude error,we propose a bipedal INS method based on the equation constraint and ellipsoid constraint,which uses foot-to-foot distance as a new observation to correct heading and altitude error.We conduct extensive and well-designed experiments to evaluate the performance of the proposed method.The experimental results indicate that the position error of our proposed method did not exceed 0.83% of the total traveled distance.
基金Y.J.Ouyang and M.Zhang contributed equally to this work.The work was supported by National Key Research and Development Program of China(Grant No.2021YFA0718700,2019YFA0704900)the National Natural Science Foundation of China(Grant No.92163211)State Key Laboratory of Advanced Technology for Materials Synthesis and Processing of Wsluhan University of Technology(2023-KF-1).
文摘Thermoelectric superlattices are expected to decouple the strong correlation between various thermo-electric parameters,and are an important strategy for excellent thermoelectric performances.The superlattices of(Bi_(2))m(Bi_(2)Te_(3))n homologous series are well-known for low lattice thermal conductivity and intriguing topological surface states.However,the impacts of electronic structure on the thermo-electric performance were still not well-understood in(Bi_(2))m(Bi_(2)Te_(3))n.To cope with this issue,Bi_(2)eBi_(2)Te_(3)superlattice-like films with adjustable Bi_(2)/(Bi_(2)+Bi_(2)Te_(3))molar ratio(R)were successfully fabricated by the molecular beam epitaxy technique.Angle-resolved photoemission spectroscopy measurements com-bined with theoretical calculations revealed the conduction band evolution from single-valley to multi-valley as R≥0.30,leading to intrinsically high carrier effective mass and improved thermoelectric power factor.Also,the superlattice film(R=0.46)with the structure close to Bi_(4)Te_(3)possesses the topological surface state feature around the high symmetry point.As a result of the high effective mass of 3.9 m0 and very high electron density of_(2).31×10^(21)cm^(-3),the film with R=0.46 acquired the highest power factor of 1.49 mW·m^(-1)·K^(-2)at 420 K,outperforming that of other(Bi_(2))m(Bi_(2)Te_(3))n superlattices.This work lays an essential foundation on understanding the electronic structure and further improving thermoelectric performances of(Bi_(2))m(Bi_(2)Te_(3))n homologous series.
