Spatiotemporal evolution of ecosystem service value and topographic gradient effect in the Da-Xiao Liangshan Mountains in Sichuan Province,China

The Da-Xiao Liangshan mountains are critical ecological function areas and essential ecological barriers in the upper reaches of the Yangtze River in China.This study selected a total of six periods of land use land cover(LULC)data from 1995 to 2020,to estimate the ecosystem service value(ESV)and analyzed its spatiotemporal evolution and topographic gradient divergence.The results showed that:(1)The ESV increased by 1.1 billion yuan,with an increase rate of 1.47%from 1995 to 2020.Two time periods,2005–2010 and 2015–2020,showed more significant increases than other periods.(2)The elevation and slope of mountainous areas determine the type of land use and further influence the spatial pattern of ESV.(3)Although woodland and grassland are the main land use types of the study area(more than 90%),the hydrological regulation function of the water area partially compensated for the impact of the encroachment of the built-up area on the ESV of grassland.(4)The spatial distribution of ESVs showed an inverted V-shaped characteristic as the topographic gradient increased,with the dominant position being the 5th topographic gradient zone.Finally,this study provided relevant recommendations for ecosystem protection and optimization.The findings of this study clarified the influence of topographical factors on the spatial differentiation of ESV and provided novel insights into ecosystem protection.

Regional difference and dynamic evolution of development quality of power industry in China

To achieve the goals of carbon peaking and carbon neutrality and maintain high-quality economic growth,China is currently striving to improve the quality of development of its power sector.In this regard,revealing the regional differences and evolutionary trends in the development quality of China’power sector has a high value to inspire the next improvement direction toward how to integrate regional power recourses to an overall optimization level.Motived by this purpose,this paper uses the entropy method to evaluate the com‐prehensive and subsystem indices of the development quality of the power industry,and reveals their re‐gional differences and evolutionary trends with the help of the Dagum Gini coefficient and Kernel density es‐timation methods.The findings show that:There are obvious regional differences in the development quality of China’s power industry,and the differences are steadily declining in all regions except the West.Regional differences are mainly derived from inter-regional differences,with the largest inter-regional differences in the East-Northeast region.Intra-regional differences show a distribution pattern of East>West>North‐east>Center.

Sand barrier morphological evolution based on time series remote sensing images:a case study of Anhaiao,Pingtan

The morphological evolution of the sand barrier in the Anhaiao coastal zone of Pingtan from 1996 to 2018 was studied.Tidal correction was used to refine the location of the coastline.A standard deviation ellipse method was applied to further analyze the movement of the barrier head with the axis and rotation angle.A natural neighbor interpolation(NNI)method was carried out to calculate the terrain of the intertidal area,and the erosion and deposition characteristics were illustrated based on the terrain.The results showed that the northern part of the sand barrier facing the lagoon area was deposited over the whole studied period,while erosion has always occurred in the southern part of the sand barrier facing the open sea.The erosion and deposition were slightly different on both sides of the barrier head due to hydrodynamic turbulence.The middle sand barrier moved 102.60 m away from its original location in 1996,and the end of the barrier moved 65.45 m.The head of the sand barrier continued moving 379 m to the northwest.Consequently,the preliminary morphological evolution of the sand barrier corresponding to the distance and direction of movement was detected.

The Investigation of the Dynamical Evolution of Extrasolar Three-planetary System GJ 3138

This article is devoted to studying the dynamical evolution and orbital stability of compact extrasolar threeplanetary system GJ 3138. In this system, all semimajor axes are less than 0.7 au. The modeling of planetary motion is performed using the averaged semi-analytical motion theory of the second order in planetary masses,which the authors construct. Unknown and known with errors orbital elements vary in allowable limits to obtain a set of initial conditions. Each of these initial conditions is applied for the modeling of planetary motion. The assumption about the stability of observed planetary systems allows to eliminate the initial conditions leading to excessive growth of the orbital eccentricities and inclinations and to identify those under which these orbital elements conserve moderate values over the whole modeling interval. Thus, it becomes possible to limit the range of possible values of unknown orbital elements and determine their most probable values in terms of stability.

A Dynamic Evolution Model of Airline Networks

Empirical data show that most of the degree distribution of airline networks assume a double power law. In this work, firstly, we assume cities as sites, Hight between two cities as an edge between two sites, and build a dynamic evolution model for airline networks by improving the BA model, in which the conception of attractiveness plays a decisive role in the course of evolution of the networks. To this end, we discuss whether the attractiveness depends on the site label s or not separately, finally we obtain analytic degree distribution. As a result, if the attractiveness of a site is independent of the degree distribution of sites, which will follow the double power law,otherwise, it will be scale-free. Moreover,degree distribution depends on the parameters of the models, and some parameters are more sensitive than others.

A semi-analytic model for the study of 1/1 resonant dynamics of the planar elliptic restricted co-orbital problem

Mean motion resonances(MMRs)are widespread in our Solar System.Moreover,resonant dynamics has always been an essential topic in planetary research.Recently,the research about exoplanets and the potential Planet Nine with large eccentricity has given rise to our interests in the secular dynamics inside MMRs in the elliptic model.In this paper,we study the fixed points of the averaged Hamiltonian and the long-term stable regions of the 1/1 resonance(or co-orbital motion)in the elliptic restricted three-body problem(ERTBP)systematically.Numerical integrations prove those test particles trapped in"apsidal co-rotation",where both the resonant angleφ_(res)and the secular angleΔω(or apsidal longitude differences)librate simultaneously,always survive the long-term simulations.Furthermore,utilizing a semianalytical method based on the adiabatic approach,three families of long-term fixed points of the averaged Hamiltonian of the planar ERTBP inside the 1/1 resonance have been found.We call them QS-points,Hpoints,and T-points here,whose values of the(φ_(res),Δω)are(0°,180°),(180°,0°),and(±60°,±60°),respectively.All the fixed points of the averaged Hamiltonian of the co-orbital motion in the ERTBP are presented in the e-e’plane(’represents the elements of the planet in this paper).We find that QS-points and T-points always exist for the arbitrary eccentricity of a planet,while H-points only exist for the cases of low e’and very high e.Furthermore,we measure the libration width in terms of eccentricity,Δe,around these stable equilibrium points in the e-Δωphase-space portraits.The"apsidal co-rotation"around all the stable equilibrium points is presented in the e-e’plane.All these results are effectively confirmed by numerical experiments.The long-term stable zones around these periodic orbits in the e-e’plane are significant for the research of the co-orbital motion in the ERTBP.Above all,these practical approaches that we proposed can also be used to study the secular dynamics of other MMRs.

2011—2020年我国卫生资源配置的地区差异和动态演进

目的分析我国2011—2020年卫生资源配置的地区差异及动态演进趋势,为提升卫生资源效率、促进优质卫生资源均衡发展提供参考依据。方法基于2011—2020年面板数据,采用熵值法对卫生资源配置水平进行综合测度,基于自然断点分级法评价卫生资源配置空间均衡性,使用泰尔指数测算卫生资源配置地区差异程度及来源与构成,通过核密度估计法探讨卫生资源配置动态演进趋势。结果观察期内,我国卫生资源配置综合水平由1.810增至1.972,中密度、次高密度、次低密度区范围扩大6.45%。较观察初期,卫生资源配置受西部地区影响的总体差异涨幅约为1.36%,区域间差异占比约为51.38%。在动态演进过程中卫生资源配置非均衡性呈轻微缩小趋势,各区域形成两极或多极化特征。结论我国卫生资源配置渐趋均衡,而区域间差异仍是我国卫生资源配置总体差异的主要来源。

Investigation of paint removal by atmospheric pressure plasma jet

Acrylic polyurethane paint on the surface of 2A12 Al alloy was cleaned utilizing an atmospheric pressure plasma jet in this work.The dynamic evolution of the paint removal process during plasma treatment with time was explored through analysis of morphology and chemical states.The results showed that although the thickness of paint could be reduced effectively with an increase in cleaning time,the removal rate of paint gradually decreased with time.During the initial cleaning process range,its original smooth morphology of paint turned rugged quickly and was almost unchanged with further plasma treatment.Element and chemical state analysis showed that the content of C in the paint layer decreased obviously after plasma treatment.In contrast,the O content increased remarkably.The cleaning mechanism could be mainly attributed to the reaction between active O-containing species in air plasma and organic components in the paint.After removal of superficial organic matter,residue inorganic metal oxide substances aggregated on the base.The exposed metal oxides on the one hand elevated the superficial O content,but on the other hand hindered further plasma penetration,resulting in a gradual decrease in cleaning rate with cleaning time.Therefore,physical wiping was proposed to be incorporated with the plasma method and effective removal of paint was realized.

Bio-inspired environmental adaptability of swarm active matter

How biologically active matters survive adaptively in complex and changeable environments is a common concern of scientists.Genetics,evolution and natural selection are vital factors in the process of biological evolution and are also the key to survival in harsh environments.However,it is challenging to intuitively and accurately reproduce such longterm adaptive survival processes in the laboratory.Although simulation experiments are intuitive and efficient,they lack fidelity.Therefore,we propose to use swarm robots to study the adaptive process of active matter swarms in complex and changeable environments.Based on a self-built virtual environmental platform and a robot swarm that can interact with the environment,we introduce the concept of genes into the robot system,giving each robot unique digital genes,and design robot breeding methods and rules for gene mutations.Our previous work[Proc.Natl.Acad.Sci.USA 119 e2120019119(2022)]has demonstrated the effectiveness of this system.In this work,by analyzing the relationship between the genetic traits of the population and the characteristics of environmental resources,and comparing different experimental conditions,we verified in both robot experiments and corresponding simulation experiments that agents with genetic inheritance can survive for a long time under the action of natural selection in periodically changing environments.We also confirmed that in the robot system,both breeding and mutation are essential factors.These findings can help answer the practical scientific question of how individuals and swarms can successfully adapt to complex,dynamic,and unpredictable actual environments.

Effect of Orbital Characteristic of Inclined Third-body on Motion of Secondary-body for a Hierarchical Triple Systems

The influence of a third-body's orbital elements on the second-body's motion in a hierarchical triple system is a crucial problem in astrophysics.Most prolonged evaluation studies have focused on a distant zero-inclined thirdbody.This study presents a new perspective on second-body motion equations that addresses a perturbing-body in an elliptic orbit derived with consideration of the axial-tilt(obliquity)of the primary.The proposed model is compared by the dual-averaged method and the N-body problem algorithm.After validation,a generalized threebody model is derived to investigate the effects of the third-body's orbital elements on secondary-body motion behavior.The proposed model considers short-time oscillations that affect secular evaluation and applies to exoplanets with all the primary and third body eccentricities,inclinations,and mass ratios.It is shown that the obliquity of the primary(or third-body's inclination)must be considered for precise long-term assessment,even in highly-hierarchical systems.

Influence of Solar Activity on Precise Orbit Prediction of LEO Satellites

The perturbations of low earth orbit(LEO)satellites operating in the orbit of 300~2000 km are complicated.In particular,the atmospheric drag force and solar radiation pressure force change rapidly over a short period of time due to solar activities.Using spaceborne global positioning system(GPS)data of the CHAMP,GRACE and SWARM satellites from 2002 to 2020,this paper studies in depth the influence of solar activity on LEO satellites’precise orbit prediction by performing a series of orbit prediction experiments.The quality of GPS data is more susceptible to being influenced by solar activity during years when this activity is high and the changes in dynamic parameters are consistent with those of solar activity.The effects of solar activity on LEO orbit prediction accuracy are analyzed by comparing the predicted orbits with the precise ones.During years of high solar activity,the average root-mean-squares prediction errors at 10,20,and 30 minutes are 0.15,0.20,and 0.26 m,respectively,which are larger than the corresponding values in low-solar-activity years by 59%,63%,and 68%,respectively.These results demonstrate that solar activity has a great influence on the orbit prediction accuracy,especially during high-solar-activity years.We should strengthen the real-time monitoring of solar activity and geomagnetic activity,and formulate corresponding orbit prediction strategies for the active solar period.

Studying the Equilibrium Points of the Modified Circular Restricted Three-body Problem: The Case of Sun–Haumea System

We intend to study a modified version of the planar Circular Restricted Three-Body Problem(CRTBP) by incorporating several perturbing parameters. We consider the bigger primary as an oblate spheroid and emitting radiation while the small primary has an elongated body. We also consider the perturbation from a disk-like structure encompassing this three-body system. First, we develop a mathematical model of this modified CRTBP.We have found there exist five equilibrium points in this modified CRTBP model, where three of them are collinear and the other two are non-collinear. Second, we apply our modified CRTBP model to the Sun–Haumea system by considering several values of each perturbing parameter. Through our numerical investigation, we have discovered that the incorporation of perturbing parameters has resulted in a shift in the equilibrium point positions of the Sun–Haumea system compared to their positions in the classical CRTBP. The stability of equilibrium points is investigated. We have shown that the collinear equilibrium points are unstable and the stability of non-collinear equilibrium points depends on the mass parameter μ of the system. Unlike the classical case, non-collinear equilibrium points have both a maximum and minimum limit of μ for achieving stability. We remark that the stability range of μ in non-collinear equilibrium points depends on the perturbing parameters. In the context of the Sun–Haumea system, we have found that the non-collinear equilibrium points are stable.

A tale of planet formation: from dust to planets

The characterization of exoplanets and their birth protoplanetary disks has enormously advanced in the last decade.Benefitting from that,our global understanding of the planet formation processes has been substantially improved.In this review,we first summarize the cutting-edge states of the exoplanet and disk observations.We further present a comprehensive panoptic view of modern core accretion planet formation scenarios,including dust growth and radial drift,planetesimal formation by the streaming instability,core growth by planetesimal accretion and pebble accretion.We discuss the key concepts and physical processes in each growth stage and elaborate on the connections between theoretical studies and observational revelations.Finally,we point out the critical questions and future directions of planet formation studies.

Regional coupling coordination degree between new urbanization and water ecological civilization in China,2009-2018

New urbanization is closely related to the construction of aquatic ecological civilization,and it promotes and restricts each other.Based on the panel data of 30 provinces in China from 2009 to 2018,this paper constructs the evaluation index system of new urbanization and water ecological civilization,determines the weight by using entropy method,and comprehensively analyzes and judges the development status and coupling coordination of new urbanization and water ecological civilization by constructing the coupling coordination model of new urbanization and water ecological civilization.The results show that the coupling coordination degree of new urbanization and water ecological civilization in most provinces and cities is in the state of barely coordination and primary coordination,and is at the level of medium coupling coordination;the overall trend is increasing,and the gap between provinces is gradually narrowing with the advance of time;In terms of regional distribution,the eastern region is higher than the central and western regions.Beijing,Shanghai,Tianjin and other places in the eastern region have realized the high-level coupling of new urbanization and water ecological civilization,while Henan,Anhui,Hunan and other places in the central region still have a large space for improvement.

Review Article: Resonant Families of Periodic Orbits in the Restricted Three-body Problem

The restricted three-body problem(RTBP) is a fundamental model in celestial mechanics.Periodic orbits in the synodic frame play a very important role in understanding the dynamics of the RTBP model.Most of these periodic orbits,when interpreted in the sidereal frame,are actually resonant periodic orbits.As a result,numerical computation of the periodic orbits is also one approach for researchers to understand the orbital resonances of the three-body problem.Extensive studies have been carried out on this topic,concerning either the circular case or the elliptic case of this model.In this paper,we make a brief review of the history and current status of the studies on resonant periodic orbits in the RTBP model.Starting from the unperturbed two-body problem,we organize the review paper by the two cases of this model—the circular restricted three-body problem and the elliptic restricted three-body problem.

Stability of the coplanar planetary four-body system

We consider the coplanar planetary four-body problem,where three planets orbit a large star without the cross of their orbits.The system is stable if there is no exchange or cross of orbits.Starting from the Sundman inequality,the equation of the kinematical boundaries is derived.We discuss a reasonable situation,where two planets with known orbits are more massive than the third one.The boundaries of possible motions are controlled by the parameter c^2E.If the actual value of c^2E is less than or equal to a critical value(c^2 E)cr,then the regions of possible motions are bounded and therefore the system is stable.The criteria obtained in special cases are applied to the Solar System and the currently known extrasolar planetary systems.Our results are checked using N-body integrator.

Dynamic investigation of oxygen defects on transition metal-based electrocatalysts:formation,characterization,and mechanism during alkaline oxygen evolution reaction

Oxygen defects play a critical role in the electrocatalytic oxygen evolution reaction(OER).Therefore,in-depth understanding the structure-activity-mechanism relationship of these defects is the key to design efficient OER electrocatalysts.This relationship needs to be understood dynamically due to the potential for irreversible phase transitions during OER.Consequently,significant efforts have been devoted to study the dynamic evolution of oxygen defects to shed light on the OER mechanism.This review critically examines and analyzes the dynamic processes occurring at oxygen defect sites during OER,including defect formation and defect evolution mechanisms,along with the advanced characterization techniques needed to understand these processes.This review aims to provide a comprehensive understanding of high-efficiency electrocatalysts,with a particular emphasis on the importance of in situ monitoring the dynamic evolution of oxygen defects,providing a new perspective towards efficient OER electrocatalyst design.

Insights into layered-tunnel dynamic structural evolution based on local coordination chemistry regulation for high-energy-density and long-cycle-life sodium-ion oxide cathodes

The pursuit of high energy density while achieving long cycle life remains a challenge in developing transition metal(TM)oxide cathode materials for sodium-ion batteries(SIBs).Here,we present a concept of precisely manipulating structural evolution via local coordination chemistry regulation to design high-performance composite cathode materials.The controllable structural evolution process is realized by tuning magnesium content in Na0.6Mn1-xMgxO2,which is elucidated by a combination of experimental analysis and theoretical calculations.The substitution of Mg into Mn sites not only induces a unique structural evolu-tion from layered–tunnel structure to layered structure but also mitigates the Jahn–Teller distortion of Mn3+.Meanwhile,benefiting from the strong ionic inter-action between Mg2+and O2-,local environments around O2-coordinated with electrochemically inactive Mg2+are anchored in the TM layer,providing a pinning effect to stabilize crystal structure and smooth electrochemical profile.The layered–tunnel Na0.6Mn0.95Mg0.05O2 cathode material delivers 188.9 mAh g-1 of specific capacity,equivalent to 508.0 Wh kg-1 of energy density at 0.5C,and exhibits 71.3%of capacity retention after 1000 cycles at 5C as well as excellent compatibility with hard carbon anode.This work may provide new insights of manipulating structural evolution in composite cathode materials via local coordi-nation chemistry regulation and inspire more novel design of high-performance SIB cathode materials.

Defect spinel oxides for electrocatalytic reduction reactions

Electrocatalytic reduction reactions play a crucial role in electrochemical energy conversion and storage technology,which are emerging technologies to ameliorate environmental problems.Spinel oxides are widely explored in electrocatalytic oxidation reactions but have a poor intrinsic ability to reduction reactions,making their electrocatalytic ability less effective.To improve this,defect engineering is a valuable method for regulating the electronic structure and coordination environment.Herein,this manuscript discusses the use of defect spinel oxides in electrocatalytic reduction reactions,including the different types of defects,construction methods,and characterization techniques.It also outlines the various applications of defect spinel oxides in different electrocatalytic reduction reactions.Finally,it goes over the challenges and future outlooks for defect spinels.This review aims to thoroughly explain how defect spinels work in electrocatalytic reduction reactions and serve as a helpful guide for creating effective electrocatalysts.

Eigen microstates and their evolutions in complex systems

Emergence refers to the existence or formation of collective behaviors in complex systems.Here,we develop a theoretical framework based on the eigen microstate theory to analyze the emerging phenomena and dynamic evolution of complex system.In this framework,the statistical ensemble composed of M microstates of a complex system with N agents is defined by the normalized N×M matrix A,whose columns represent microstates and order of row is consist with the time.The ensemble matrix A can be decomposed as■,where r=min(N,M),eigenvalueσIbehaves as the probability amplitude of the eigen microstate U_I so that■and U_I evolves following V_I.In a disorder complex system,there is no dominant eigenvalue and eigen microstate.When a probability amplitudeσIbecomes finite in the thermodynamic limit,there is a condensation of the eigen microstate UIin analogy to the Bose–Einstein condensation of Bose gases.This indicates the emergence of U_I and a phase transition in complex system.Our framework has been applied successfully to equilibrium threedimensional Ising model,climate system and stock markets.We anticipate that our eigen microstate method can be used to study non-equilibrium complex systems with unknown orderparameters,such as phase transitions of collective motion and tipping points in climate systems and ecosystems.