Mobility is one of the major new paradigms of the current Internet, and this is driving most of the research activity in networking throughout the World. The Mobility of Wireless Sensor Networks (WSN) has become a hot...Mobility is one of the major new paradigms of the current Internet, and this is driving most of the research activity in networking throughout the World. The Mobility of Wireless Sensor Networks (WSN) has become a hot research theme in recent years due to its wide range of applications ranging from medical research to military. The widely adopted standard for wireless sensor network platform is IEEE 802.15.4/ZigBee. The IEEE 802.15.4/ZigBee is considered the “technology of choice” due to low-power, cost-effective communication and the reliability they provide. In this paper, we perform extensive network evaluation, to study the Effect of coordinator mobility on ZigBee mesh network, using OPNET Modeler. In mobile coordinator, the type of the trajectory along with the node density and the traffic are the major factors that decide the system performance. The results obtained from the wide analysis of ZigBee mesh network shows variation when the routers are placed at Hexagonal configuration with a mobile coordinator. In this paper, variations in load metric is analyzed in hexagonal configuration by enabling and disabling ACK. Thus the status of ACK also plays a critical role in analysing load metrics.展开更多
The clothing industry is booming,and clothing prices are more affordable today.People's requirements for clothing are no longer limited to the question of enough clothing to wear.In order to solve the main problem...The clothing industry is booming,and clothing prices are more affordable today.People's requirements for clothing are no longer limited to the question of enough clothing to wear.In order to solve the main problem that consumers have a lot of clothes but don't know how to match and look good,this article aims to design a matchmaker application(app)-Coordinator app.Through analyzing the current situation of existing apparel matching apps and typical case,the paper summarizes the existing clothing,the advantages and disadvantages of matching apps,and the combine with user needs survey feedback,to design the main four modules required by the Coordinator app which are elaborated and displayed separately.展开更多
Owing to limited bandwidth, high bit error rate, and bursty error in the wireless environment, the performance of the transmission control protocol （TCP） degrades greatly in wireless networks. Up to now, many resear...Owing to limited bandwidth, high bit error rate, and bursty error in the wireless environment, the performance of the transmission control protocol （TCP） degrades greatly in wireless networks. Up to now, many researchers have contributed greatly to the wireless TCP field. However, in most of their works, the wireless TCP module usually works in the TCP layer and has no idea of the actual time of the packet transmission, which is determined by the Scheduler in the media access control （MAC） layer, and this will bring the inaccuracy to the local retransmission fimeout and induce the redundant local retransmission. In this article, a coordinator is introduced into the base-station （BS）, which can provide efficient cooperation between the TCP module and the scheduler module. On the bais of the performance analysis and simulation results, the proposed method is shown to eliminate redundant local retransmission, increase throughput, and improve TCP-level fairness in wireless networks. Moreover, this scheme is orthogonal to those existing wireless TCP schemes, thus it can give great compatibility to the current networks, and further enhance the performance of TCP under the condition that the performance improvement benefiting from the existing approaches will not be affected.展开更多
Wireless personal area networks （WPANs） are formed in a relatively small area, and coordinator that serves as a central control device plays an important role in the operation and organization of a piconet. Typical ...Wireless personal area networks （WPANs） are formed in a relatively small area, and coordinator that serves as a central control device plays an important role in the operation and organization of a piconet. Typical applications of WPANs include home automation systems, security systems and health monitoring systems. In these types of systems, guaranteeing seamless connectivity is very important, and communications cannot take place when the coordinator malfunctions. Thus, in the case of a breakdown, it is necessary to elect a new coordinator as soon as possible. For this reason, a distributed coordinator election scheme （DCES） is proposed that considers not only QoS support but also network connectivity in an effort to avoid possible network partition. Simulation results show that the proposed scheme can elect a new coordinator while maintaining QoS and guaranteeing connectivity for a limited period.展开更多
In wind power transmission via modular multilevel converter based high voltage direct current(MMCHVDC)systems,under traditional control strategies,MMC-HVDCcannot provide inertia support to the receiving-end grid(REG)d...In wind power transmission via modular multilevel converter based high voltage direct current(MMCHVDC)systems,under traditional control strategies,MMC-HVDCcannot provide inertia support to the receiving-end grid(REG)during disturbances.Moreover,due to the frequency decoupling between the two ends of the MMCHVDC,the sending-end wind farm(SEWF)cannot obtain the frequency variation information of the REG to provide inertia response.Therefore,this paper proposes a novel coordinated source-network-storage inertia control strategy based on wind power transmission via MMC-HVDC system.First,the grid-side MMC station(GS-MMC)maps the frequency variations of the REG to direct current(DC)voltage variations through the frequency mapping control,and uses submodule capacitor energy to provide inertial power.Then,the wind farm-side MMC station(WF-MMC)restores the DC voltage variations to frequency variations through the frequency restoration control and power loss compensation,providing real-time frequency information for the wind farm.Finally,based on real-time frequency information,thewind farmutilizes the rotor kinetic energy and energy storage to provide fast and lasting power support through the wind-storage coordinated inertia control strategy.Meanwhile,when the wind turbines withdraw from the inertia response phase,the energy storage can increase the power output to compensate for the power deficit,preventing secondary frequency drops.Furthermore,this paper uses small-signal analysis to determine the appropriate values for the key parameters of the proposed control strategy.A simulation model of the wind power transmission via MMCHVDC system is built in MATLAB/Simulink environment to validate and evaluate the proposed method.The results show that the proposed coordinated control strategy can effectively improve the system inertia level and avoid the secondary frequency drop under the load sudden increase condition.展开更多
The neuromuscular junction and its proregenerative niche:The mammalian peripheral nervous system,unlike the central nervous system,has preserved throughout evolution the ability to regenerate and fully restore functio...The neuromuscular junction and its proregenerative niche:The mammalian peripheral nervous system,unlike the central nervous system,has preserved throughout evolution the ability to regenerate and fully restore function.Key factors for effective nerve regeneration include a supportive neuronal environment and a coordinated tissue response(Brosius Lutz and Barres,2014).展开更多
Sluggish sulfur redox kinetics remain a critical bottleneck in the advancement of high-performance lithiumsulfur batteries(LSBs).Single-atom catalysts(SACs)offer a promising solution to this limitation,particularly wh...Sluggish sulfur redox kinetics remain a critical bottleneck in the advancement of high-performance lithiumsulfur batteries(LSBs).Single-atom catalysts(SACs)offer a promising solution to this limitation,particularly when their coordination structures are carefully engineered.Here,we develop a chromium-based SAC featuring a unique undercoordinated CrN_(3) configuration to boost sulfur electrochemistry.Compared with conventional CrN_(4),the CrN_(3) motif lowers 3d orbital occupancy and meanwhile activates the in-plane hybridizations with S 3p orbitals upon interaction with polysulfides,contributing to moderate adsorption strength and reduced energy barriers for bidirectional sulfur conversions.Additionally,the integration of the two-dimensional(2D)porous framework ensures abundant electrochemically active surfaces and efficiently exposed active sites.As a result,CrN_(3)-based cells demonstrate fast and durable sulfur redox reactions,enabling an ultralow capacity decay of 0.0075%per cycle over 1000 cycles and a high-rate capability of 651.9 mAh·g^(-1)at 5 C.The CrN_(3) catalyst retains robust catalytic efficiency under demanding conditions,delivering a high areal capacity of 5.53 mAh·cm^(-2) at high sulfur loading and lean electrolyte.This work establishes a compelling paradigm of SAC coordination engineering for designing advanced sulfur electrocatalysts for next-generation LSBs.展开更多
Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development...Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development of highly efficient SACs and a comprehensive understanding of their structure-activity relationships remain enormously challenging.Herein,a novel kind of Fe-based SAC featuring an asymmetric FeN_(5)-TeN_(4) coordination structure was precisely designed by introducing Te atom adjacent to the Fe active center to enhance the catalytic activity.Theoretical calculations reveal that the neighboring Te atom modulates the local coordination environment of the central Fe site,elevating the d-band center closer to the Fermi level and strengthening the d-p orbital hybridization between the catalyst and sulfur species,thereby immobilizing polysulfides and improving the bidirectional catalysis of Li-S redox.Consequently,the Fe-Te atom pair catalyst endows Li-S batteries with exceptional rate performance,achieving a high specific capacity of 735 mAh g^(−1) at 5 C,and remarkable cycling stability with a low decay rate of 0.038%per cycle over 1000 cycles at 1 C.This work provides fundamental insights into the electronic structure modulation of SACs and establishes a clear correlation between precisely engineered atomic configurations and their enhanced catalytic performance in Li-S electrochemistry.展开更多
Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)...Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)control strategy based on a power outer loop and voltage-current inner loops,aiming to enhance the stability and current-limiting capability of GFM converters during grid fault conditions.During voltage sags,the GFM converter’s voltage source behavior is maintained by dynamically adjusting the reactive power reference to provide voltage support,thereby effectively suppressing the steady-state component of the fault current.To address the active power imbalance induced by voltage sags,a dynamic active power reference correction method based on apparent power is designed to mitigate power angle oscillations and limit transient current.Moreover,an adaptive virtual impedance loop is implemented to enhance dynamic transient current-limiting performance during the fault initiation phase.This approach improves the responsiveness of the inner loop and ensures safe system operation under various fault severities.Under asymmetric fault conditions,a negative-sequence reactive current compensation strategy is incorporated to further suppress negative-sequence voltage and improve voltage symmetry.The proposed control scheme enables coordinated operation of multiple control objectives,including voltage support,current suppression,and power angle stability,across different fault scenarios.Finally,MATLAB/Simulink simulation results validate the effectiveness of the proposed strategy,showcasing its superior performance in current limiting and power angle stability,thereby significantly enhancing the system’s fault ride-through capability.展开更多
Traffic at urban intersections frequently encounters unexpected obstructions,resulting in congestion due to uncooperative and priority-based driving behavior.This paper presents an optimal right-turn coordination syst...Traffic at urban intersections frequently encounters unexpected obstructions,resulting in congestion due to uncooperative and priority-based driving behavior.This paper presents an optimal right-turn coordination system for Connected and Automated Vehicles(CAVs)at single-lane intersections,particularly in the context of left-hand side driving on roads.The goal is to facilitate smooth right turns for certain vehicles without creating bottlenecks.We consider that all approaching vehicles share relevant information through vehicular communications.The Intersection Coordination Unit(ICU)processes this information and communicates the optimal crossing or turning times to the vehicles.The primary objective of this coordination is to minimize overall traffic delays,which also helps improve the fuel consumption of vehicles.By considering information from upcoming vehicles at the intersection,the coordination system solves an optimization problem to determine the best timing for executing right turns,ultimately minimizing the total delay for all vehicles.The proposed coordination system is evaluated at a typical urban intersection,and its performance is compared to traditional traffic systems.Numerical simulation results indicate that the proposed coordination system significantly enhances the average traffic speed and fuel consumption compared to the traditional traffic system in various scenarios.展开更多
Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt...Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt-based electrocatalysts,emphasizing their structural engineering for enhanced the performance of electrocatalytic nitrate reduction reaction(NO3RR)through dimensional control,compositional tuning,and coordination microenvironment modulation.Notably,by critically analyzing metallic cobalt,cobalt alloys,cobalt compounds,cobalt single atom and molecular catalyst configurations,we firstly establish correlations between atomic-scale structural features and catalytic performance in a coordination environment perspective for NO3RR,including the dynamic reconstruction during operation and its impact on active site.Synergizing experimental breakthroughs with computational modeling,we decode mechanisms underlying competitive hydrogen evolution suppression,intermediate adsorption-energy optimization,and durability enhancement in complex aqueous environments.The development of cobalt-based catalysts was summarized and prospected,and the emerging opportunities of machine learning in accelerating the research and development of high-performance catalysts and the configuration of series reactors for scalable nitrate-to-ammonia systems were also introduced.Bridging surface science and applications,it outlines a framework for designing multifunctional electrocatalysts to restore nitrogen cycle balance sustainably.展开更多
The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)at...The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)attenuation behavior remain poorly understood.To address this gap,a thermodynamically controlled periodic coordination strategy is proposed to achieve precise modulation of magnetic nanoparticle spacing.This approach unveils the evolution of magnetic domain configurations,progressing from individual to coupled and ultimately to crosslinked domain configurations.A unique magnetic coupling phenomenon surpasses the Snoek limit in low-frequency range,which is observed through micromagnetic simulation.The crosslinked magnetic configuration achieves effective low-frequency EM wave absorption at 3.68 GHz,encompassing nearly the entire C-band.This exceptional magnetic interaction significantly enhances radar camouflage and thermal insulation properties.Additionally,a robust gradient metamaterial design extends coverage across the full band(2–40 GHz),effectively mitigating the impact of EM pollution on human health and environment.This comprehensive study elucidates the evolution mechanisms of magnetic domain configurations,addresses gaps in dynamic magnetic modulation,and provides novel insights for the development of high-performance,low-frequency EM wave absorption materials.展开更多
A novel coordination polymer(CP){[Cd_(2)(L)(1,4-bimb)_(1.5)(DMF)_(2)]·DMF}n(1)(H_(4)L=5,5'-[1,1'-biphenyl-4,4'-diylbis(oxy)]diisophthalic acid,1,4-bimb=1,4-bis(imidazole-1-ylmethyl)-benzene)has been d...A novel coordination polymer(CP){[Cd_(2)(L)(1,4-bimb)_(1.5)(DMF)_(2)]·DMF}n(1)(H_(4)L=5,5'-[1,1'-biphenyl-4,4'-diylbis(oxy)]diisophthalic acid,1,4-bimb=1,4-bis(imidazole-1-ylmethyl)-benzene)has been designed and synthesized through solvothermal reaction.Structural analysis shows that Cd(Ⅱ)is connected by H4L and 1,4-bimb to form a 2D network,and 1,4-bimb further expands the 2D network into a 3D framework.CP 1 can be used as an excellent fluorescence sensor for Fe^(3+)and 4-nitrophenol(4-NP),with low detection limits and good anti-interference.The detection limits of Fe^(3+)and 4-NP were 0.034 and 0.031μmol·L^(-1),respectively.In addition,the fluorescence quenching mechanism was studied.1 was successfully applied to determine Fe^(3+)and 4-NP content in the Yanhe River water sample.CCDC:2351092.展开更多
Studying the coupling coordination development of new energy vehicles(NEVs)and the ecological environment in China is helpful in promoting the development of NEVs in the country and is of great significance in promoti...Studying the coupling coordination development of new energy vehicles(NEVs)and the ecological environment in China is helpful in promoting the development of NEVs in the country and is of great significance in promoting high-quality development of new energy in China.This paper constructs an evaluation index system for the development of NEVs and the ecological environment.It uses game theory combining weighting model,particle swarm optimized projection tracking evaluation model,coupling coordination degree model,and machine learning algorithms to calculate and analyze the level of coupling coordination development of NEVs and the ecological environment in China from 2010 to 2021,and identifies the driving factors.The research results show that:(i)From 2010 to 2021,the development index of NEVs in China has steadily increased from 0.085 to 0.634,while the ecological environment level index significantly rose from 0.170 to 0.884,reflecting the continuous development of China in both NEVs and the ecological environment.(ii)From 2010 to 2012,the two systems—new energy vehicle(NEV)development and the ecological environment—were in a period of imbalance and decline.From 2013 to 2016,they underwent a transition period,and from 2017 to 2021,they entered a period of coordinated development showing a trend of benign and continuous improvement.By 2021,they reached a good level of coordination.(iii)Indicators such as the number of patents granted for NEVs,water consumption per unit of GDP,and energy consumption per unit of GDP are the main driving factors affecting the coupling coordination development of NEVs and the ecological environment in China.展开更多
This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expan...This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expansion with environmental protection,a comprehensive evaluation index system is constructed,encompassing two key dimensions:regional economy and ecological environment.Using panel data from 2013 to 2022,the coupling coordination degree model is employed to quantify the interactions and synergy between these dimensions.Additionally,spatial econometric methods are applied to calculate both global and local Moran’s Index,revealing spatial clustering patterns,regional disparities,and heterogeneity.The relative development model further identifies critical factors influencing regional coordination,with a focus on the lagging development of basic infrastructure and public services.The findings demonstrate a positive temporal trend toward improved regional coordination and reduced development gaps,with a spatial pattern characterized by higher coupling degrees in eastern and central regions compared to western areas.Based on these results,this study proposes actionable strategies to enhance coordinated development,emphasizing ecological conservation,the establishment of green production and consumption systems,ecological restoration,and strengthened municipal collaboration.This revised abstract emphasizes the study’s purpose,methods,and key findings more clearly while maintaining a professional and concise tone.Finally,based on the above analysis results,the corresponding coordinated development suggestions of regional economy and ecological environment are given from the aspects of ecological environment protection measures,green production and consumption system construction,ecological environment restoration and municipal coordination.展开更多
With the boom in maritime activities,the need for highly reliable maritime communication is becoming urgent,which is an important component of 5G/6G communication networks.However,the bandwidth reuse characteristic of...With the boom in maritime activities,the need for highly reliable maritime communication is becoming urgent,which is an important component of 5G/6G communication networks.However,the bandwidth reuse characteristic of 5G/6G networks will inevitably lead to severe interference,resulting in degradation in the communication performance of maritime users.In this paper,we propose a safe deep reinforcement learning based interference coordination scheme to jointly optimize the power control and bandwidth allocation in maritime communication systems,and exploit the quality-of-service requirements of users as the risk value references to evaluate the communication policies.In particular,this scheme designs a deep neural network to select the communication policies through the evaluation network and update the parameters using the target network,which improves the communication performance and speeds up the convergence rate.Moreover,the Nash equilibrium of the interference coordination game and the computational complexity of the proposed scheme are analyzed.Simulation and experimental results verify the performance gain of the proposed scheme compared with benchmarks.展开更多
As the development of new power systems accelerates and the impacts of high renewable energy integration and extreme weather intensify,grid-alternative energy storage is garnering increasing attention for its grid-int...As the development of new power systems accelerates and the impacts of high renewable energy integration and extreme weather intensify,grid-alternative energy storage is garnering increasing attention for its grid-interaction benefits and clear business models.Consequently,assessing the value of grid-alternative energy storage in the systemtransition has become critically important.Considering the performance characteristics of storage,we propose a value assessment frame-work for grid-alternative energy storage,quantifying its non-wires-alternative effects from both cost and benefit perspectives.Building on this,we developed a collaborative planning model for energy storage and transmission grids,aimed at maximizing the economic benefits of storage systems while balancing investment and operational costs.The model considers regional grid interconnections and their interactions with system operation.By participating in system operations,grid-alternative energy storage not only maximizes its own economic benefits but also generates social welfare transfer effects.Furthermore,based on multi-regional interconnected planning,grid-alternative energy storage can reduce system costs by approximately 35%,with the most significant changes observed in generation costs.Multi-regional coordinated planning significantly enhances the sys-tem’s flexibility in regulation.However,when the load factor of interconnection lines between regions remains constant,system operational flexibility tends to decrease,leading to a roughly 28.9%increase in storage investment.Additionally,under regional coordinated planning,the greater the disparity in wind power integration across interconnected regions,the more noticeable the reduction in system costs.展开更多
Zwitterions(ZIs)are considered as an ideal,novel ionic conductive medium due to their high dipole moment and good solubility of lithium salts.However,the strong interactions between ZIs and Li^(+)severely hinder Li^(+...Zwitterions(ZIs)are considered as an ideal,novel ionic conductive medium due to their high dipole moment and good solubility of lithium salts.However,the strong interactions between ZIs and Li^(+)severely hinder Li^(+)migration.Herein,a quasi-solid electrolyte(MSQSE-2Na)was fabricated by adding sodium bis(fluorosulfonyl)imide(NaFSI)to sulfobetaine methacrylate(SBMA,a ZI)based polymerization system.Na^(+)occupies the–SO_(3)^(-)site in SBMA prior to Li^(+),which weakens the self-crosslinking of SBMA and frees the Li^(+)bound to the polymer segments.Thus,the polymer conformation of MSQSE-2Na changes to a relaxed,homogeneous"sea-island"type.Meanwhile,Na^(+),due to its electron-withdrawing effect,decreases the electron cloud density of the polymer segments,building a weakly coordinated environment in MSQSE-2Na.Consequently,MSQSE-2Na exhibits excellent ionic conductivity of 7.38×10^(-4)S cm^(-1)and a high Li^(+)transference number of 0.632 at 25℃.The(-)Li|MSQSE-2Na|Li(+)cells exhibit super stability,sustaining operation for over 6182h.The(-)Li|MSQSE-2Na|LiFePO_(4)(+)cells demonstrate outstanding charge/discharge reversibility with a Coulombic efficiency exceeding 99.9%over 270 cycles(≈4500 h),with a capacity retention of 70.0%.This work proposes a new design concept for regulating the polymer conformation and charge characteristics through competitive coordination,thereby advancing the application of ZI-based polymer electrolytes in lithium metal batteries.展开更多
文摘Mobility is one of the major new paradigms of the current Internet, and this is driving most of the research activity in networking throughout the World. The Mobility of Wireless Sensor Networks (WSN) has become a hot research theme in recent years due to its wide range of applications ranging from medical research to military. The widely adopted standard for wireless sensor network platform is IEEE 802.15.4/ZigBee. The IEEE 802.15.4/ZigBee is considered the “technology of choice” due to low-power, cost-effective communication and the reliability they provide. In this paper, we perform extensive network evaluation, to study the Effect of coordinator mobility on ZigBee mesh network, using OPNET Modeler. In mobile coordinator, the type of the trajectory along with the node density and the traffic are the major factors that decide the system performance. The results obtained from the wide analysis of ZigBee mesh network shows variation when the routers are placed at Hexagonal configuration with a mobile coordinator. In this paper, variations in load metric is analyzed in hexagonal configuration by enabling and disabling ACK. Thus the status of ACK also plays a critical role in analysing load metrics.
文摘The clothing industry is booming,and clothing prices are more affordable today.People's requirements for clothing are no longer limited to the question of enough clothing to wear.In order to solve the main problem that consumers have a lot of clothes but don't know how to match and look good,this article aims to design a matchmaker application(app)-Coordinator app.Through analyzing the current situation of existing apparel matching apps and typical case,the paper summarizes the existing clothing,the advantages and disadvantages of matching apps,and the combine with user needs survey feedback,to design the main four modules required by the Coordinator app which are elaborated and displayed separately.
文摘Owing to limited bandwidth, high bit error rate, and bursty error in the wireless environment, the performance of the transmission control protocol （TCP） degrades greatly in wireless networks. Up to now, many researchers have contributed greatly to the wireless TCP field. However, in most of their works, the wireless TCP module usually works in the TCP layer and has no idea of the actual time of the packet transmission, which is determined by the Scheduler in the media access control （MAC） layer, and this will bring the inaccuracy to the local retransmission fimeout and induce the redundant local retransmission. In this article, a coordinator is introduced into the base-station （BS）, which can provide efficient cooperation between the TCP module and the scheduler module. On the bais of the performance analysis and simulation results, the proposed method is shown to eliminate redundant local retransmission, increase throughput, and improve TCP-level fairness in wireless networks. Moreover, this scheme is orthogonal to those existing wireless TCP schemes, thus it can give great compatibility to the current networks, and further enhance the performance of TCP under the condition that the performance improvement benefiting from the existing approaches will not be affected.
基金supported by the MKE (The Ministry of Knowledge Economy), Korea, under the ITRC (Information Technology Research Center) support program supervised by the IITA (Institute for Information Technology Advancement)" under Grant No.IITA-2009-C1090-0902-0019
文摘Wireless personal area networks （WPANs） are formed in a relatively small area, and coordinator that serves as a central control device plays an important role in the operation and organization of a piconet. Typical applications of WPANs include home automation systems, security systems and health monitoring systems. In these types of systems, guaranteeing seamless connectivity is very important, and communications cannot take place when the coordinator malfunctions. Thus, in the case of a breakdown, it is necessary to elect a new coordinator as soon as possible. For this reason, a distributed coordinator election scheme （DCES） is proposed that considers not only QoS support but also network connectivity in an effort to avoid possible network partition. Simulation results show that the proposed scheme can elect a new coordinator while maintaining QoS and guaranteeing connectivity for a limited period.
基金funded by State Grid Corporation of China Central Branch Technology Project(52140024000C).
文摘In wind power transmission via modular multilevel converter based high voltage direct current(MMCHVDC)systems,under traditional control strategies,MMC-HVDCcannot provide inertia support to the receiving-end grid(REG)during disturbances.Moreover,due to the frequency decoupling between the two ends of the MMCHVDC,the sending-end wind farm(SEWF)cannot obtain the frequency variation information of the REG to provide inertia response.Therefore,this paper proposes a novel coordinated source-network-storage inertia control strategy based on wind power transmission via MMC-HVDC system.First,the grid-side MMC station(GS-MMC)maps the frequency variations of the REG to direct current(DC)voltage variations through the frequency mapping control,and uses submodule capacitor energy to provide inertial power.Then,the wind farm-side MMC station(WF-MMC)restores the DC voltage variations to frequency variations through the frequency restoration control and power loss compensation,providing real-time frequency information for the wind farm.Finally,based on real-time frequency information,thewind farmutilizes the rotor kinetic energy and energy storage to provide fast and lasting power support through the wind-storage coordinated inertia control strategy.Meanwhile,when the wind turbines withdraw from the inertia response phase,the energy storage can increase the power output to compensate for the power deficit,preventing secondary frequency drops.Furthermore,this paper uses small-signal analysis to determine the appropriate values for the key parameters of the proposed control strategy.A simulation model of the wind power transmission via MMCHVDC system is built in MATLAB/Simulink environment to validate and evaluate the proposed method.The results show that the proposed coordinated control strategy can effectively improve the system inertia level and avoid the secondary frequency drop under the load sudden increase condition.
基金supported by the University of Padua(to MR)by the project“RIPANE”of the Italian Ministry of Defense(to CM)by Cariparo Foundation(to CM)。
文摘The neuromuscular junction and its proregenerative niche:The mammalian peripheral nervous system,unlike the central nervous system,has preserved throughout evolution the ability to regenerate and fully restore function.Key factors for effective nerve regeneration include a supportive neuronal environment and a coordinated tissue response(Brosius Lutz and Barres,2014).
基金the National Natural Science Foundation of China(No.22379069)Fundamental Research Funds for the Central Universities(No.30922010304).
文摘Sluggish sulfur redox kinetics remain a critical bottleneck in the advancement of high-performance lithiumsulfur batteries(LSBs).Single-atom catalysts(SACs)offer a promising solution to this limitation,particularly when their coordination structures are carefully engineered.Here,we develop a chromium-based SAC featuring a unique undercoordinated CrN_(3) configuration to boost sulfur electrochemistry.Compared with conventional CrN_(4),the CrN_(3) motif lowers 3d orbital occupancy and meanwhile activates the in-plane hybridizations with S 3p orbitals upon interaction with polysulfides,contributing to moderate adsorption strength and reduced energy barriers for bidirectional sulfur conversions.Additionally,the integration of the two-dimensional(2D)porous framework ensures abundant electrochemically active surfaces and efficiently exposed active sites.As a result,CrN_(3)-based cells demonstrate fast and durable sulfur redox reactions,enabling an ultralow capacity decay of 0.0075%per cycle over 1000 cycles and a high-rate capability of 651.9 mAh·g^(-1)at 5 C.The CrN_(3) catalyst retains robust catalytic efficiency under demanding conditions,delivering a high areal capacity of 5.53 mAh·cm^(-2) at high sulfur loading and lean electrolyte.This work establishes a compelling paradigm of SAC coordination engineering for designing advanced sulfur electrocatalysts for next-generation LSBs.
基金supported by the National Natural Science Foundation(52302284,22002086,22204096)Shanghai Sailing Program(23YF1412200)the Fundamental Research Funds for the Central Universities(22120240314).
文摘Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development of highly efficient SACs and a comprehensive understanding of their structure-activity relationships remain enormously challenging.Herein,a novel kind of Fe-based SAC featuring an asymmetric FeN_(5)-TeN_(4) coordination structure was precisely designed by introducing Te atom adjacent to the Fe active center to enhance the catalytic activity.Theoretical calculations reveal that the neighboring Te atom modulates the local coordination environment of the central Fe site,elevating the d-band center closer to the Fermi level and strengthening the d-p orbital hybridization between the catalyst and sulfur species,thereby immobilizing polysulfides and improving the bidirectional catalysis of Li-S redox.Consequently,the Fe-Te atom pair catalyst endows Li-S batteries with exceptional rate performance,achieving a high specific capacity of 735 mAh g^(−1) at 5 C,and remarkable cycling stability with a low decay rate of 0.038%per cycle over 1000 cycles at 1 C.This work provides fundamental insights into the electronic structure modulation of SACs and establishes a clear correlation between precisely engineered atomic configurations and their enhanced catalytic performance in Li-S electrochemistry.
文摘Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)control strategy based on a power outer loop and voltage-current inner loops,aiming to enhance the stability and current-limiting capability of GFM converters during grid fault conditions.During voltage sags,the GFM converter’s voltage source behavior is maintained by dynamically adjusting the reactive power reference to provide voltage support,thereby effectively suppressing the steady-state component of the fault current.To address the active power imbalance induced by voltage sags,a dynamic active power reference correction method based on apparent power is designed to mitigate power angle oscillations and limit transient current.Moreover,an adaptive virtual impedance loop is implemented to enhance dynamic transient current-limiting performance during the fault initiation phase.This approach improves the responsiveness of the inner loop and ensures safe system operation under various fault severities.Under asymmetric fault conditions,a negative-sequence reactive current compensation strategy is incorporated to further suppress negative-sequence voltage and improve voltage symmetry.The proposed control scheme enables coordinated operation of multiple control objectives,including voltage support,current suppression,and power angle stability,across different fault scenarios.Finally,MATLAB/Simulink simulation results validate the effectiveness of the proposed strategy,showcasing its superior performance in current limiting and power angle stability,thereby significantly enhancing the system’s fault ride-through capability.
基金supported by the Japan Society for the Promotion of Science(JSPS)Grants-in-Aid for Scientific Research(C)23K03898.
文摘Traffic at urban intersections frequently encounters unexpected obstructions,resulting in congestion due to uncooperative and priority-based driving behavior.This paper presents an optimal right-turn coordination system for Connected and Automated Vehicles(CAVs)at single-lane intersections,particularly in the context of left-hand side driving on roads.The goal is to facilitate smooth right turns for certain vehicles without creating bottlenecks.We consider that all approaching vehicles share relevant information through vehicular communications.The Intersection Coordination Unit(ICU)processes this information and communicates the optimal crossing or turning times to the vehicles.The primary objective of this coordination is to minimize overall traffic delays,which also helps improve the fuel consumption of vehicles.By considering information from upcoming vehicles at the intersection,the coordination system solves an optimization problem to determine the best timing for executing right turns,ultimately minimizing the total delay for all vehicles.The proposed coordination system is evaluated at a typical urban intersection,and its performance is compared to traditional traffic systems.Numerical simulation results indicate that the proposed coordination system significantly enhances the average traffic speed and fuel consumption compared to the traditional traffic system in various scenarios.
基金supported by the National Natural Science Foundation of China(Grant Nos.:21825201,52401244 and 52201227)Henan Province Key Research and Development and Promotion Program(Scientific and Technological Breakthrough Project:232102240088 and 252102230078)+3 种基金the Key Research&Development and Promotion of Special Project(Scientific Problem Tackling)of Henan Province(252102230078)Doctoral Research Startup Fund Project of Henan Open University(BSJH-2025-04)Zhejiang Provincial Natural Science Foundation of China(LQ24B020005,LQ23B030001)China Postdoctoral Science Foundation(2024M762442).
文摘Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt-based electrocatalysts,emphasizing their structural engineering for enhanced the performance of electrocatalytic nitrate reduction reaction(NO3RR)through dimensional control,compositional tuning,and coordination microenvironment modulation.Notably,by critically analyzing metallic cobalt,cobalt alloys,cobalt compounds,cobalt single atom and molecular catalyst configurations,we firstly establish correlations between atomic-scale structural features and catalytic performance in a coordination environment perspective for NO3RR,including the dynamic reconstruction during operation and its impact on active site.Synergizing experimental breakthroughs with computational modeling,we decode mechanisms underlying competitive hydrogen evolution suppression,intermediate adsorption-energy optimization,and durability enhancement in complex aqueous environments.The development of cobalt-based catalysts was summarized and prospected,and the emerging opportunities of machine learning in accelerating the research and development of high-performance catalysts and the configuration of series reactors for scalable nitrate-to-ammonia systems were also introduced.Bridging surface science and applications,it outlines a framework for designing multifunctional electrocatalysts to restore nitrogen cycle balance sustainably.
基金supported by the National Natural Science Foundation of China(22265021,52231007,and 12327804)the Aeronautical Science Foundation of China(2020Z056056003)Jiangxi Provincial Natural Science Foundation(20232BAB212004).
文摘The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)attenuation behavior remain poorly understood.To address this gap,a thermodynamically controlled periodic coordination strategy is proposed to achieve precise modulation of magnetic nanoparticle spacing.This approach unveils the evolution of magnetic domain configurations,progressing from individual to coupled and ultimately to crosslinked domain configurations.A unique magnetic coupling phenomenon surpasses the Snoek limit in low-frequency range,which is observed through micromagnetic simulation.The crosslinked magnetic configuration achieves effective low-frequency EM wave absorption at 3.68 GHz,encompassing nearly the entire C-band.This exceptional magnetic interaction significantly enhances radar camouflage and thermal insulation properties.Additionally,a robust gradient metamaterial design extends coverage across the full band(2–40 GHz),effectively mitigating the impact of EM pollution on human health and environment.This comprehensive study elucidates the evolution mechanisms of magnetic domain configurations,addresses gaps in dynamic magnetic modulation,and provides novel insights for the development of high-performance,low-frequency EM wave absorption materials.
文摘A novel coordination polymer(CP){[Cd_(2)(L)(1,4-bimb)_(1.5)(DMF)_(2)]·DMF}n(1)(H_(4)L=5,5'-[1,1'-biphenyl-4,4'-diylbis(oxy)]diisophthalic acid,1,4-bimb=1,4-bis(imidazole-1-ylmethyl)-benzene)has been designed and synthesized through solvothermal reaction.Structural analysis shows that Cd(Ⅱ)is connected by H4L and 1,4-bimb to form a 2D network,and 1,4-bimb further expands the 2D network into a 3D framework.CP 1 can be used as an excellent fluorescence sensor for Fe^(3+)and 4-nitrophenol(4-NP),with low detection limits and good anti-interference.The detection limits of Fe^(3+)and 4-NP were 0.034 and 0.031μmol·L^(-1),respectively.In addition,the fluorescence quenching mechanism was studied.1 was successfully applied to determine Fe^(3+)and 4-NP content in the Yanhe River water sample.CCDC:2351092.
基金Supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_0102)the China Scholarship Council Program(202406190114)。
文摘Studying the coupling coordination development of new energy vehicles(NEVs)and the ecological environment in China is helpful in promoting the development of NEVs in the country and is of great significance in promoting high-quality development of new energy in China.This paper constructs an evaluation index system for the development of NEVs and the ecological environment.It uses game theory combining weighting model,particle swarm optimized projection tracking evaluation model,coupling coordination degree model,and machine learning algorithms to calculate and analyze the level of coupling coordination development of NEVs and the ecological environment in China from 2010 to 2021,and identifies the driving factors.The research results show that:(i)From 2010 to 2021,the development index of NEVs in China has steadily increased from 0.085 to 0.634,while the ecological environment level index significantly rose from 0.170 to 0.884,reflecting the continuous development of China in both NEVs and the ecological environment.(ii)From 2010 to 2012,the two systems—new energy vehicle(NEV)development and the ecological environment—were in a period of imbalance and decline.From 2013 to 2016,they underwent a transition period,and from 2017 to 2021,they entered a period of coordinated development showing a trend of benign and continuous improvement.By 2021,they reached a good level of coordination.(iii)Indicators such as the number of patents granted for NEVs,water consumption per unit of GDP,and energy consumption per unit of GDP are the main driving factors affecting the coupling coordination development of NEVs and the ecological environment in China.
基金support from Guangdong Science and Technology(20230505)Guangdong Provincial Philosophy and Social Science Planning Project(GD20SQ25)Guangdong Provincial Special Fund for Science and Technology Innovation Strategy in 2024(Cultivation of College Students’Science and Technology Innovation)(pdjh2024a391)during preparation of this manuscript.
文摘This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expansion with environmental protection,a comprehensive evaluation index system is constructed,encompassing two key dimensions:regional economy and ecological environment.Using panel data from 2013 to 2022,the coupling coordination degree model is employed to quantify the interactions and synergy between these dimensions.Additionally,spatial econometric methods are applied to calculate both global and local Moran’s Index,revealing spatial clustering patterns,regional disparities,and heterogeneity.The relative development model further identifies critical factors influencing regional coordination,with a focus on the lagging development of basic infrastructure and public services.The findings demonstrate a positive temporal trend toward improved regional coordination and reduced development gaps,with a spatial pattern characterized by higher coupling degrees in eastern and central regions compared to western areas.Based on these results,this study proposes actionable strategies to enhance coordinated development,emphasizing ecological conservation,the establishment of green production and consumption systems,ecological restoration,and strengthened municipal collaboration.This revised abstract emphasizes the study’s purpose,methods,and key findings more clearly while maintaining a professional and concise tone.Finally,based on the above analysis results,the corresponding coordinated development suggestions of regional economy and ecological environment are given from the aspects of ecological environment protection measures,green production and consumption system construction,ecological environment restoration and municipal coordination.
文摘With the boom in maritime activities,the need for highly reliable maritime communication is becoming urgent,which is an important component of 5G/6G communication networks.However,the bandwidth reuse characteristic of 5G/6G networks will inevitably lead to severe interference,resulting in degradation in the communication performance of maritime users.In this paper,we propose a safe deep reinforcement learning based interference coordination scheme to jointly optimize the power control and bandwidth allocation in maritime communication systems,and exploit the quality-of-service requirements of users as the risk value references to evaluate the communication policies.In particular,this scheme designs a deep neural network to select the communication policies through the evaluation network and update the parameters using the target network,which improves the communication performance and speeds up the convergence rate.Moreover,the Nash equilibrium of the interference coordination game and the computational complexity of the proposed scheme are analyzed.Simulation and experimental results verify the performance gain of the proposed scheme compared with benchmarks.
基金funded by the Technology Project of State Grid Jibei Electric Power Supply Co.,Ltd.(Grant Number:52018F240001).
文摘As the development of new power systems accelerates and the impacts of high renewable energy integration and extreme weather intensify,grid-alternative energy storage is garnering increasing attention for its grid-interaction benefits and clear business models.Consequently,assessing the value of grid-alternative energy storage in the systemtransition has become critically important.Considering the performance characteristics of storage,we propose a value assessment frame-work for grid-alternative energy storage,quantifying its non-wires-alternative effects from both cost and benefit perspectives.Building on this,we developed a collaborative planning model for energy storage and transmission grids,aimed at maximizing the economic benefits of storage systems while balancing investment and operational costs.The model considers regional grid interconnections and their interactions with system operation.By participating in system operations,grid-alternative energy storage not only maximizes its own economic benefits but also generates social welfare transfer effects.Furthermore,based on multi-regional interconnected planning,grid-alternative energy storage can reduce system costs by approximately 35%,with the most significant changes observed in generation costs.Multi-regional coordinated planning significantly enhances the sys-tem’s flexibility in regulation.However,when the load factor of interconnection lines between regions remains constant,system operational flexibility tends to decrease,leading to a roughly 28.9%increase in storage investment.Additionally,under regional coordinated planning,the greater the disparity in wind power integration across interconnected regions,the more noticeable the reduction in system costs.
基金supported by the National Natural Science Foundation of China(22078228)。
文摘Zwitterions(ZIs)are considered as an ideal,novel ionic conductive medium due to their high dipole moment and good solubility of lithium salts.However,the strong interactions between ZIs and Li^(+)severely hinder Li^(+)migration.Herein,a quasi-solid electrolyte(MSQSE-2Na)was fabricated by adding sodium bis(fluorosulfonyl)imide(NaFSI)to sulfobetaine methacrylate(SBMA,a ZI)based polymerization system.Na^(+)occupies the–SO_(3)^(-)site in SBMA prior to Li^(+),which weakens the self-crosslinking of SBMA and frees the Li^(+)bound to the polymer segments.Thus,the polymer conformation of MSQSE-2Na changes to a relaxed,homogeneous"sea-island"type.Meanwhile,Na^(+),due to its electron-withdrawing effect,decreases the electron cloud density of the polymer segments,building a weakly coordinated environment in MSQSE-2Na.Consequently,MSQSE-2Na exhibits excellent ionic conductivity of 7.38×10^(-4)S cm^(-1)and a high Li^(+)transference number of 0.632 at 25℃.The(-)Li|MSQSE-2Na|Li(+)cells exhibit super stability,sustaining operation for over 6182h.The(-)Li|MSQSE-2Na|LiFePO_(4)(+)cells demonstrate outstanding charge/discharge reversibility with a Coulombic efficiency exceeding 99.9%over 270 cycles(≈4500 h),with a capacity retention of 70.0%.This work proposes a new design concept for regulating the polymer conformation and charge characteristics through competitive coordination,thereby advancing the application of ZI-based polymer electrolytes in lithium metal batteries.
