The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited im...The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited imaginary frequencies in their phonon spectra at 0 GPa.Here,we conducted a systematic investigation of P-N compounds using first-principles calculations,uncovering a series of structurally similar stable phases,C2/m-PN_(x)(x=6,8,10,12,and 14),in which N forms zigzag N chains similar to those in Ch-N.In P-N compounds,the longest zigzag N-chain,which can theoretically remain stable under ambient pressure,is the N-chain composed of 14 N atoms in C2/m-PN14.If the N-chain continues to grow,imaginary interchain vibrational frequencies arise in the system.Notably,N chains with an even number of atoms were more likely to be energetically favorable.The five C2/m-PN_(x) phases and one metastable phase(R-PN_(6))exhibited remarkable stability and excellent detonability at ambient pressure,indicating that they are promising candidates for high-energy-density materials.In addition,R-PN_(6) was the first structure to stabilize the N_(6) ring through covalent bonding,with the covalent network contributing to its high hardness(47.59 GPa).展开更多
Purpose-This study explores how managerial leadership and organizational innovation interact to enhance resilience and risk management in railway supply chains and how these capabilities contribute to sustained compet...Purpose-This study explores how managerial leadership and organizational innovation interact to enhance resilience and risk management in railway supply chains and how these capabilities contribute to sustained competitive advantage.It emphasizes the strategic importance of resilience in railway systems that face operational complexity,regulatory pressures and increasing exposure to systemic risks.Design/methodology/approach-A mixed-methods design was employed,integrating survey data from 186 railway organizations with six case studies involving railway operators,rolling stock manufacturers and supply chain partners across multiple regions.Constructs were measured using validated scales and hypothesized relationships were tested using Structural Equation Modeling(SEM).Case study interviews were analyzed thematically to provide contextual understanding of leadership practices and innovation strategies.Findings-The results confirm that transformational managerial leadership significantly predicts innovation adoption,which in turn strengthens resilience and risk management capabilities.Resilience emerged as a powerful driver of competitive advantage,reinforcing its role as a strategic capability rather than a reactive response to disruptions.Furthermore,innovation was shown to partially mediate the relationship between leadership and resilience,highlighting its function as the operational channel through which vision translates into capability.Originality/value-This study contributes to the literature by integrating the Resource-Based View(RBV)and Dynamic Capabilities(DC)framework into the context of railway supply chains.It is among the first to empirically validate the mediating role of innovation between leadership and resilience,offering both theoretical advancements and actionable strategies for building resilient and competitive railway systems.展开更多
Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researchin...Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researching geohazard,from regional to individual scale.The methodology includes the establishment of geological chain inventories,discrimination of geohazard chain modes,analyses of dynamics and dam breaches,and risk assessments.The following results were obtained:(1)In the downstream of Yarlung Zangbo River,175 sites were identified as high-risk for river blockage disasters,indicating the development of watershed geohazards.Five geohazard chain modes were summarized by incorporating geomorphological characteristics,historical events,landslide zoning,and materials.The risk areas of typical hazard were identified and assessed using InSAR data.(2)Glacier-related watershed geohazard chains are significantly different from traditional landslides.A detailed inversion analysis was conducted on the massive rock-ice avalanche in the Sedongpu gully in 2021.This particular event lasted roughly 300 seconds,with a maximum flow velocity of 77.2 m/s and a maximum flow height of 93 meters.By scrutinizing the dynamic processes and mechanical characteristics,mobility stages and phase transitions can be divided into four stages.(3)Watershed geohazard chains tend to block rivers.The peak breach discharge of the Yigong Landslide reached 12.4×10^(4) m^(3)/s,which is 36 times the volume of the seasonal flood discharge in the Yigong River.Megafloods caused by landslide dam breaches have significantly shaped the geomorphology.This study offers insights into disaster patterns and the multistaged movement characteristics of glacier-related watershed geohazard chains,providing a comprehensive method for investigations and assessments in glacial regions.展开更多
In response to the challenges presented by the unreliable identity of the master node,high communication overhead,and limited network support size within the Practical Byzantine Fault-Tolerant(PBFT)algorithm for conso...In response to the challenges presented by the unreliable identity of the master node,high communication overhead,and limited network support size within the Practical Byzantine Fault-Tolerant(PBFT)algorithm for consortium chains,we propose an improved PBFT algorithm based on XGBoost grouping called XG-PBFT in this paper.XG-PBFT constructs a dataset by training important parameters that affect node performance,which are used as classification indexes for nodes.The XGBoost algorithm then is employed to train the dataset,and nodes joining the system will be grouped according to the trained grouping model.Among them,the nodes with higher parameter indexes will be assigned to the consensus group to participate in the consensus,and the rest of the nodes will be assigned to the general group to receive the consensus results.In order to reduce the resource waste of the system,XG-PBFT optimizes the consensus protocol for the problem of high complexity of PBFT communication.Finally,we evaluate the performance of XG-PBFT.The experimental results show that XG-PBFT can significantly improve the performance of throughput,consensus delay and communication complexity compared to the original PBFT algorithm,and the performance enhancement is significant compared to other algorithms in the case of a larger number of nodes.The results demonstrate that the XG-PBFT algorithm is more suitable for large-scale consortium chains.展开更多
A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety problems.Our study addresses the...A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety problems.Our study addresses these problems by proposing a modified polyrotaxane(mPR)-based solid polymer electrolyte(SPE)design that simultaneously mitigates solvent-related problems and improves conductivity.mPR-SPE exhibits high ion conductivity(2.8×10^(−3)S cm^(−1)at 25℃)through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain dispersion.Integrating this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 cycles.In situ Raman spectroscopy reveals the presence of an LiO_(2)intermediate alongside Li_(2)O_(2)during oxygen reactions.Ex situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture,as demonstrated by the air permeability tests.The present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.展开更多
A glacier hazard chain can form a long-runout mass flow and generate a large flood,affecting downstream areas hundreds of kilometers away from the initiating hazard site.This study focuses on the Yarlung Zangbo Daxiag...A glacier hazard chain can form a long-runout mass flow and generate a large flood,affecting downstream areas hundreds of kilometers away from the initiating hazard site.This study focuses on the Yarlung Zangbo Daxiagu.The objective is to address two key unresolved issues:the evolution of detached glacier materials into debris flows or debris floods and the amplification of the impact range and threats.A comprehensive framework is developed that considers the impacts of near-field and far-field hazards.Numerical modeling,remote sensing,and field investigations were integrated to understand the interactions,transformations,and amplifications of hazards in the glacier hazard chain.The results indicate that extensive,nearly saturated sediments on the glacier valley floor,when entrained,amplify the magnitude of the mass flow.The topography plays a crucial role.When the valley outlet is perpendicular to the river course,topographic obstacles cause immediate halting,resulting in the formation of high barrier dams.Conversely,when the glacier valley aligns nearly parallel to the river course,the mass flow can travel a much longer distance upon entering the river,causing an enlarged affected area.The barrier dams can breach rapidly,causing breaching floods that amplify the downstream impact from several kilometers to hundreds of kilometers.Our analysis reveals that the overall impacts remain spatially limited.Specifically,downstream areas along the Yarlung Zangbo-Brahmaputra River are unlikely to face greater threats from the upstream floods than local monsoon floods.Our findings provide the foundation for the management of glacier hazard chains.展开更多
The philosophical concept of one bond connecting the world is an established scientific and economic phenomenon today.The global industrial and supply chains are symbols of that universal link of fraternity,cooperatio...The philosophical concept of one bond connecting the world is an established scientific and economic phenomenon today.The global industrial and supply chains are symbols of that universal link of fraternity,cooperation and globalization.Despite a few major economies still trying to push forward a decoupling agenda and favoring a“small yard,high fence”strategy,globalization and cooperation remain a global trend.展开更多
The China International Supply Chain Expo is an important window through which to observe the trends of China's supply chain transformation.GEOPOLITICAL unrest,climate change challenges,and advances in digital tec...The China International Supply Chain Expo is an important window through which to observe the trends of China's supply chain transformation.GEOPOLITICAL unrest,climate change challenges,and advances in digital technology have reshaped the global supply chain in recent years.展开更多
We investigate the mixed-state entanglement between two spins embedded in the XXZ Heisenberg chain under thermal equilibrium.By deriving an analytical expression for the entanglement of two-spin thermal states and ext...We investigate the mixed-state entanglement between two spins embedded in the XXZ Heisenberg chain under thermal equilibrium.By deriving an analytical expression for the entanglement of two-spin thermal states and extending this analysis to larger spin chains,we demonstrate that mixed-state entanglement is profoundly shaped by both disorder and temperature.Our results reveal a sharp distinction between many-body localized and ergodic phases,with entanglement vanishing above diferent fnite temperature thresholds.Furthermore,by analyzing non-adjacent spins,we uncover an approximate exponential decay of entanglement with separation.This work advances the understanding of the quantum-to-classical transition by linking the entanglement properties of small subsystems to the broader thermal environment,ofering an explanation for the absence of entanglement in macroscopic systems.These fndings provide critical insights into quantum many-body physics,bridging concepts from thermalization,localization,and quantum information theory.展开更多
As global trade networks deepen and trade patterns evolve,supply chain dynamics have emerged as a critical driver of high-quality development-particularly as reflected in firms’capacity to export higher-quality produ...As global trade networks deepen and trade patterns evolve,supply chain dynamics have emerged as a critical driver of high-quality development-particularly as reflected in firms’capacity to export higher-quality products.Drawing on new-new trade theory,this study incorporates supply chain behavior-specifically,the use of intermediate goods-into the analytical framework for determining export product quality.Theoretically,it posits that technical regulations on the supply chain influence export quality through two key channels:improvements in the quality of intermediate inputs and changes in their associated costs.Empirically,the study exploits China’s imposition of technical barriers to trade(TBT)on intermediate goods imports as a quasi-natural experiment,applying a difference-in-differences approach to firm-level export data from 2000 to 2014.The results show that supply chain technical regulations lead to significant improvements in the quality of exported final products.Mechanistically,the regulations raise the quality of imported intermediates,which in turn drive upgrades in final outputs,while leaving import costs largely unchanged-since compliance expenses are absorbed by foreign exporters rather than passed on to Chinese firms.Further analysis reveals substantial heterogeneity in these effects,depending on both the type of regulation and firm characteristics.These variations reflect differences in regulatory intensity and in firms’sensitivity to supply chain changes,adaptability,and capacity to convert input quality into product upgrades.Overall,the findings suggest that strengthening supply-side regulatory standards-when properly designed-represents a strategic lever for improving product quality and enhancing firms’international competitiveness,offering valuable insights for trade policy and global supply chain governance.展开更多
Photovoltaics play an essential role in supporting the unprecedented growth of renewable energy transition as well as facing a series of trade risks due to complex international dynamics and intermittent trade disrupt...Photovoltaics play an essential role in supporting the unprecedented growth of renewable energy transition as well as facing a series of trade risks due to complex international dynamics and intermittent trade disruptions.By combining complex network modeling and shock propagation analysis,the spatial-temporal evolution of photovoltaic supply chains worldwide was depicted,and the potential trade risks under different scenarios were elucidated in this study.The results show that the trade patterns of photovoltaic supply chains have evolved significantly,particularly characterized by the rise of China,Malaysia,Vietnam,and Thailand.The complexity of photovoltaic supply chains increases significantly with the addition of more nodes and edges in the networks.The vulnerability of critical photovoltaic supply chains tends to intensify with the increasing concentration of global supply chains in a geographic sense.The interruption of trade ties between China and Vietnam may lead to the most drastic impact on photovoltaic supply chains,followed by trade disruptions between Southeast Asia and North America.By unveiling the spatial-temporal network evolution and potential trade disruption of global photovoltaic supply chains,it is practical to propose rational and feasible strategies that consider the geographical diversification and international cooperation of photovoltaic supply chains worldwide.展开更多
This geo-historical case study analyses Vistelius’ingenious idea of conceptual stochastic models and their application as Markov chain analysis in the geosciences.Vistelius(1915–1995)is regarded as one of the founde...This geo-historical case study analyses Vistelius’ingenious idea of conceptual stochastic models and their application as Markov chain analysis in the geosciences.Vistelius(1915–1995)is regarded as one of the founders of mathematical geology.He was the fi rst to defi ne mathematical geology as“a scientifi c discipline concerned with the construction,analysis and use of conceptual mathematical models of geological events to solve concrete problems”(Vistelius in Principles of mathematical geology,Nauka,Leningrad,1980;Principles of mathematical geology,Kluwer Academic Publishers,Dordrecht,1992).Mathematical models in this context should be primarily probabilistic because of the large number of infl uencing natural factors.They must be conceptual to avoid fundamental errors in application.Vistelius devoted his seminal book to geological random sequences and their description and analysis using Markov models as stochastic tools.He applied this approach to grain sequences in granitic intrusive rocks and to sedimentary rock layers.Among other things,Vistelius has used Markov chain analysis in mineral resource exploration to distinguish between“ideal”granites,which are not subsequently mineralized,and mainly hydrothermally mineralized,sometimes ore-bearing granites which contain at least two generations of main minerals.The application of this special conceptual stochastic model is demonstrated on Lusatian granite(Saxony,Germany).展开更多
Electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising approach to complete the carbon cycle and potentially convert CO_(2)into valuable chemicals and fuels.Cu is unique among transition metals in its abi...Electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising approach to complete the carbon cycle and potentially convert CO_(2)into valuable chemicals and fuels.Cu is unique among transition metals in its ability to catalyze the CO_(2)RR and produce multi-carbon products.However,achieving high selectivity for C2+products is challenging for copper-based catalysts,as C–C coupling reactions proceed slowly.Herein,a surface modification strategy involving grafting long alkyl chains onto copper nanowires(Cu NWs)has been proposed to regulate the electronic structure of Cu surface,which facilitates*CO-*CO coupling in the CO_(2)RR.The hydrophobicity of the catalysts increases greatly after the introduction of long alkyl chains,therefore the hydrogen evolution reaction(HER)has been inhibited effectively.Such surface modification approach proves to be highly efficient and universal,with the Faradaic efficiency(FE)of C_(2)H_(4) up to 53%for the optimized Cu–SH catalyst,representing a significant enhancement compared to the pristine Cu NWs(30%).In-situ characterizations and theoretical calculations demonstrate that the different terminal groups of the grafted octadecyl chains can effectively regulate the charge density of Cu NWs interface and change the adsorption configuration of*CO intermediate.The top-adsorbed*CO intermediates(*COtop)on Cu–SH catalytic interface endow Cu–SH with the highest charge density,which effectively lowers the reaction energy barrier for*CO-*CO coupling,promoting the formation of the*OCCO intermediate,thereby enhancing the selectivity towards C_(2)H_(4).This study provides a promising method for designing efficient Cu-based catalysts with high catalytic activity and selectivity towards C2H4.展开更多
Rice straw,a by-product of rice cultivation,is commonly disposed of through open-field burning,which contributes to air pollution and environmental degradation.This study aims to identify the key factors influencing f...Rice straw,a by-product of rice cultivation,is commonly disposed of through open-field burning,which contributes to air pollution and environmental degradation.This study aims to identify the key factors influencing farmers’decisions on rice straw management and to develop policy recommendations that encourage the sustainable utilization of rice straw within the supply chain.A mixed-methods approach was adopted,combining qualitative interviews with nine key informants and a quantitative survey of 585 rice farmers across Thailand.Multinomial Logit Regression(MLR)was employed to analyze farmers’preferences among four management options:burning,composting,animal feeding,and selling.The results reveal that membership in farmer groups,ownership of livestock,access to baling machinery,knowledge,and skills related to straw utilization,ease of field access,availability of storage facilities,engagement in integrated farming,and year-round access to baling services significantly increased the likelihood of choosing sustainable alternatives over the burning straw.These findings underscore the importance of both capacity-building and infrastructure in enabling sustainable practices.Based on these insights,the study proposes a multi-level policy framework to enhance the value creation of rice straw.National policies should focus on expanding access to machinery and supporting innovation,while local governments should facilitate farmer training and improve straw logistics.Strengthening farmer organizations and market connections is also crucial for scaling adoption.Overall,structural integration and stakeholder coordination are key to reducing straw burning and promoting sustainable resource use in rice-producing regions.展开更多
The evolution of human societal systems rarely manifests qualitative leaps or revolutionary transformations.More commonly observed are subtle,cumulative evolutionary processes characterized by smooth transitions of in...The evolution of human societal systems rarely manifests qualitative leaps or revolutionary transformations.More commonly observed are subtle,cumulative evolutionary processes characterized by smooth transitions of incremental developments.Such evolutionary trajectories can generally be described through quantitative change patterns within societal systems.Yet,what constitutes sustainable development in human society?How might sustainable development be articulated or operationalized?The Three Chains Theory under the framework of System Exchange Theory provides a preliminary exploration and analysis of these questions,offering tentative interpretations.展开更多
Agricultural production(especially intensive rice production)is a primary income source for over 2.0×10^(7) people in the Vietnamese Mekong River Delta.However,adverse climate change impacts,socio-economic change...Agricultural production(especially intensive rice production)is a primary income source for over 2.0×10^(7) people in the Vietnamese Mekong River Delta.However,adverse climate change impacts,socio-economic change,and high dependence on farm inputs for intensive production constrain the longer-term sustainability of rice systems.Government and agribusiness actors are encouraging more farmers to grow non-rice crops and supporting the upscaling of alternative crops to paddy rice.We used a qualitative approach to investigate the value chain characteristics,as well as constraints and opportunities of alternative crops via two case studies(baby corn and honeydew melon)in An Giang and Hau Giang provinces,Vietnam.Data collection involved focus group discussions with local farmers and interviews with farmers and industry experts.Thematic analysis was used to compile the findings,and the results were validated with local government staff.The baby corn value chain featured on-going and stable market demand(including value-addition)and better vertical coordination(e.g.,written contracts and financial support).The honeydew melon value chain featured positive relationships between farmers and traders despite less-developed vertical coordination.There are opportunities for value chain engagement through product quality certification,value-addition,and accessing high-value domestic and export markets.However,farmers require crop-specific and generic support from private and public sectors.Increased labour requirements and limited access to finance and credit limit value chain participation.Upscaling and marketing alternative crops can enhance farmer profitability and support non-farming agricultural business establishment,economic growth,and community development.Efficient value chains will be critical to ensure the adoption of alternative crops and development of crop-specific agribusiness models.These findings can inform policy-makers and change facilitators in designing targeted interventions to support the adoption of alternative crops in the study area as well as in Vietnam and globally.展开更多
基金supported by the Anhui Provincial Natural Science Foundation (Grant No.2508085J006)CASHIPS Director's Fund (Grant No.YZJJ202207-CX)。
文摘The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited imaginary frequencies in their phonon spectra at 0 GPa.Here,we conducted a systematic investigation of P-N compounds using first-principles calculations,uncovering a series of structurally similar stable phases,C2/m-PN_(x)(x=6,8,10,12,and 14),in which N forms zigzag N chains similar to those in Ch-N.In P-N compounds,the longest zigzag N-chain,which can theoretically remain stable under ambient pressure,is the N-chain composed of 14 N atoms in C2/m-PN14.If the N-chain continues to grow,imaginary interchain vibrational frequencies arise in the system.Notably,N chains with an even number of atoms were more likely to be energetically favorable.The five C2/m-PN_(x) phases and one metastable phase(R-PN_(6))exhibited remarkable stability and excellent detonability at ambient pressure,indicating that they are promising candidates for high-energy-density materials.In addition,R-PN_(6) was the first structure to stabilize the N_(6) ring through covalent bonding,with the covalent network contributing to its high hardness(47.59 GPa).
文摘Purpose-This study explores how managerial leadership and organizational innovation interact to enhance resilience and risk management in railway supply chains and how these capabilities contribute to sustained competitive advantage.It emphasizes the strategic importance of resilience in railway systems that face operational complexity,regulatory pressures and increasing exposure to systemic risks.Design/methodology/approach-A mixed-methods design was employed,integrating survey data from 186 railway organizations with six case studies involving railway operators,rolling stock manufacturers and supply chain partners across multiple regions.Constructs were measured using validated scales and hypothesized relationships were tested using Structural Equation Modeling(SEM).Case study interviews were analyzed thematically to provide contextual understanding of leadership practices and innovation strategies.Findings-The results confirm that transformational managerial leadership significantly predicts innovation adoption,which in turn strengthens resilience and risk management capabilities.Resilience emerged as a powerful driver of competitive advantage,reinforcing its role as a strategic capability rather than a reactive response to disruptions.Furthermore,innovation was shown to partially mediate the relationship between leadership and resilience,highlighting its function as the operational channel through which vision translates into capability.Originality/value-This study contributes to the literature by integrating the Resource-Based View(RBV)and Dynamic Capabilities(DC)framework into the context of railway supply chains.It is among the first to empirically validate the mediating role of innovation between leadership and resilience,offering both theoretical advancements and actionable strategies for building resilient and competitive railway systems.
基金supported by the National Natural Science Foundation of China(Nos.U2244227,U2244226,42177172)the National Key R&D Program of China(No.2022YFC3004301)China Geological Survey Project(No.DD20230538)。
文摘Frequent glacier-related watershed geohazard chains are causing severe damage to life and infrastructure,reported consistently from the Eastern Himalayan Syntaxis.This paper presents a systematic method for researching geohazard,from regional to individual scale.The methodology includes the establishment of geological chain inventories,discrimination of geohazard chain modes,analyses of dynamics and dam breaches,and risk assessments.The following results were obtained:(1)In the downstream of Yarlung Zangbo River,175 sites were identified as high-risk for river blockage disasters,indicating the development of watershed geohazards.Five geohazard chain modes were summarized by incorporating geomorphological characteristics,historical events,landslide zoning,and materials.The risk areas of typical hazard were identified and assessed using InSAR data.(2)Glacier-related watershed geohazard chains are significantly different from traditional landslides.A detailed inversion analysis was conducted on the massive rock-ice avalanche in the Sedongpu gully in 2021.This particular event lasted roughly 300 seconds,with a maximum flow velocity of 77.2 m/s and a maximum flow height of 93 meters.By scrutinizing the dynamic processes and mechanical characteristics,mobility stages and phase transitions can be divided into four stages.(3)Watershed geohazard chains tend to block rivers.The peak breach discharge of the Yigong Landslide reached 12.4×10^(4) m^(3)/s,which is 36 times the volume of the seasonal flood discharge in the Yigong River.Megafloods caused by landslide dam breaches have significantly shaped the geomorphology.This study offers insights into disaster patterns and the multistaged movement characteristics of glacier-related watershed geohazard chains,providing a comprehensive method for investigations and assessments in glacial regions.
文摘In response to the challenges presented by the unreliable identity of the master node,high communication overhead,and limited network support size within the Practical Byzantine Fault-Tolerant(PBFT)algorithm for consortium chains,we propose an improved PBFT algorithm based on XGBoost grouping called XG-PBFT in this paper.XG-PBFT constructs a dataset by training important parameters that affect node performance,which are used as classification indexes for nodes.The XGBoost algorithm then is employed to train the dataset,and nodes joining the system will be grouped according to the trained grouping model.Among them,the nodes with higher parameter indexes will be assigned to the consensus group to participate in the consensus,and the rest of the nodes will be assigned to the general group to receive the consensus results.In order to reduce the resource waste of the system,XG-PBFT optimizes the consensus protocol for the problem of high complexity of PBFT communication.Finally,we evaluate the performance of XG-PBFT.The experimental results show that XG-PBFT can significantly improve the performance of throughput,consensus delay and communication complexity compared to the original PBFT algorithm,and the performance enhancement is significant compared to other algorithms in the case of a larger number of nodes.The results demonstrate that the XG-PBFT algorithm is more suitable for large-scale consortium chains.
基金supported by a National Research Foundation of Korea(NRF)Grant funded by the Ministry of Science and ICT(2021R1A2C1014294,2022R1A2C3003319)the BK21 FOUR(Fostering Outstanding Universities for Research)through the National Research Foundation(NRF)of Korea.
文摘A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety problems.Our study addresses these problems by proposing a modified polyrotaxane(mPR)-based solid polymer electrolyte(SPE)design that simultaneously mitigates solvent-related problems and improves conductivity.mPR-SPE exhibits high ion conductivity(2.8×10^(−3)S cm^(−1)at 25℃)through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain dispersion.Integrating this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 cycles.In situ Raman spectroscopy reveals the presence of an LiO_(2)intermediate alongside Li_(2)O_(2)during oxygen reactions.Ex situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture,as demonstrated by the air permeability tests.The present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.
基金support from the National Natural Science Foundation of China(U20A20112,42061160480,42377196,and 52479095)the NSFC/RGC Joint Research Scheme(42061160480 and N_HKUST620/20)+1 种基金the Research Grants Council of the Hong Kong SAR Government(16203720,T22-606/23-R,and JRFS25266S09)the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone(HZQB-KCZYB-2020083)。
文摘A glacier hazard chain can form a long-runout mass flow and generate a large flood,affecting downstream areas hundreds of kilometers away from the initiating hazard site.This study focuses on the Yarlung Zangbo Daxiagu.The objective is to address two key unresolved issues:the evolution of detached glacier materials into debris flows or debris floods and the amplification of the impact range and threats.A comprehensive framework is developed that considers the impacts of near-field and far-field hazards.Numerical modeling,remote sensing,and field investigations were integrated to understand the interactions,transformations,and amplifications of hazards in the glacier hazard chain.The results indicate that extensive,nearly saturated sediments on the glacier valley floor,when entrained,amplify the magnitude of the mass flow.The topography plays a crucial role.When the valley outlet is perpendicular to the river course,topographic obstacles cause immediate halting,resulting in the formation of high barrier dams.Conversely,when the glacier valley aligns nearly parallel to the river course,the mass flow can travel a much longer distance upon entering the river,causing an enlarged affected area.The barrier dams can breach rapidly,causing breaching floods that amplify the downstream impact from several kilometers to hundreds of kilometers.Our analysis reveals that the overall impacts remain spatially limited.Specifically,downstream areas along the Yarlung Zangbo-Brahmaputra River are unlikely to face greater threats from the upstream floods than local monsoon floods.Our findings provide the foundation for the management of glacier hazard chains.
文摘The philosophical concept of one bond connecting the world is an established scientific and economic phenomenon today.The global industrial and supply chains are symbols of that universal link of fraternity,cooperation and globalization.Despite a few major economies still trying to push forward a decoupling agenda and favoring a“small yard,high fence”strategy,globalization and cooperation remain a global trend.
文摘The China International Supply Chain Expo is an important window through which to observe the trends of China's supply chain transformation.GEOPOLITICAL unrest,climate change challenges,and advances in digital technology have reshaped the global supply chain in recent years.
基金supported by the National Natural Science Foundation of China(Grant Nos.92365202,12475011,and 11921005)the National Key R&D Program of China(Grant No.2024YFA1409002)Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)。
文摘We investigate the mixed-state entanglement between two spins embedded in the XXZ Heisenberg chain under thermal equilibrium.By deriving an analytical expression for the entanglement of two-spin thermal states and extending this analysis to larger spin chains,we demonstrate that mixed-state entanglement is profoundly shaped by both disorder and temperature.Our results reveal a sharp distinction between many-body localized and ergodic phases,with entanglement vanishing above diferent fnite temperature thresholds.Furthermore,by analyzing non-adjacent spins,we uncover an approximate exponential decay of entanglement with separation.This work advances the understanding of the quantum-to-classical transition by linking the entanglement properties of small subsystems to the broader thermal environment,ofering an explanation for the absence of entanglement in macroscopic systems.These fndings provide critical insights into quantum many-body physics,bridging concepts from thermalization,localization,and quantum information theory.
基金supported by a major project from the Key Research Base of Humanities and Social Sciences of the Ministry of Education,“Research on Open Development and High-Quality Integrated Development of the Yangtze River Delta Region”(Grant No.22JJD790035).
文摘As global trade networks deepen and trade patterns evolve,supply chain dynamics have emerged as a critical driver of high-quality development-particularly as reflected in firms’capacity to export higher-quality products.Drawing on new-new trade theory,this study incorporates supply chain behavior-specifically,the use of intermediate goods-into the analytical framework for determining export product quality.Theoretically,it posits that technical regulations on the supply chain influence export quality through two key channels:improvements in the quality of intermediate inputs and changes in their associated costs.Empirically,the study exploits China’s imposition of technical barriers to trade(TBT)on intermediate goods imports as a quasi-natural experiment,applying a difference-in-differences approach to firm-level export data from 2000 to 2014.The results show that supply chain technical regulations lead to significant improvements in the quality of exported final products.Mechanistically,the regulations raise the quality of imported intermediates,which in turn drive upgrades in final outputs,while leaving import costs largely unchanged-since compliance expenses are absorbed by foreign exporters rather than passed on to Chinese firms.Further analysis reveals substantial heterogeneity in these effects,depending on both the type of regulation and firm characteristics.These variations reflect differences in regulatory intensity and in firms’sensitivity to supply chain changes,adaptability,and capacity to convert input quality into product upgrades.Overall,the findings suggest that strengthening supply-side regulatory standards-when properly designed-represents a strategic lever for improving product quality and enhancing firms’international competitiveness,offering valuable insights for trade policy and global supply chain governance.
基金supported by the National Social Science Fund of China(Grant No.22CJY202)the National Natural Science Foundation of China(Grants No.42371183 and 72348003)+1 种基金the Programme of Kezhen-Bingwei Excellent Young Talents(Grant No.2023RC002)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2023058).
文摘Photovoltaics play an essential role in supporting the unprecedented growth of renewable energy transition as well as facing a series of trade risks due to complex international dynamics and intermittent trade disruptions.By combining complex network modeling and shock propagation analysis,the spatial-temporal evolution of photovoltaic supply chains worldwide was depicted,and the potential trade risks under different scenarios were elucidated in this study.The results show that the trade patterns of photovoltaic supply chains have evolved significantly,particularly characterized by the rise of China,Malaysia,Vietnam,and Thailand.The complexity of photovoltaic supply chains increases significantly with the addition of more nodes and edges in the networks.The vulnerability of critical photovoltaic supply chains tends to intensify with the increasing concentration of global supply chains in a geographic sense.The interruption of trade ties between China and Vietnam may lead to the most drastic impact on photovoltaic supply chains,followed by trade disruptions between Southeast Asia and North America.By unveiling the spatial-temporal network evolution and potential trade disruption of global photovoltaic supply chains,it is practical to propose rational and feasible strategies that consider the geographical diversification and international cooperation of photovoltaic supply chains worldwide.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘This geo-historical case study analyses Vistelius’ingenious idea of conceptual stochastic models and their application as Markov chain analysis in the geosciences.Vistelius(1915–1995)is regarded as one of the founders of mathematical geology.He was the fi rst to defi ne mathematical geology as“a scientifi c discipline concerned with the construction,analysis and use of conceptual mathematical models of geological events to solve concrete problems”(Vistelius in Principles of mathematical geology,Nauka,Leningrad,1980;Principles of mathematical geology,Kluwer Academic Publishers,Dordrecht,1992).Mathematical models in this context should be primarily probabilistic because of the large number of infl uencing natural factors.They must be conceptual to avoid fundamental errors in application.Vistelius devoted his seminal book to geological random sequences and their description and analysis using Markov models as stochastic tools.He applied this approach to grain sequences in granitic intrusive rocks and to sedimentary rock layers.Among other things,Vistelius has used Markov chain analysis in mineral resource exploration to distinguish between“ideal”granites,which are not subsequently mineralized,and mainly hydrothermally mineralized,sometimes ore-bearing granites which contain at least two generations of main minerals.The application of this special conceptual stochastic model is demonstrated on Lusatian granite(Saxony,Germany).
文摘Electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising approach to complete the carbon cycle and potentially convert CO_(2)into valuable chemicals and fuels.Cu is unique among transition metals in its ability to catalyze the CO_(2)RR and produce multi-carbon products.However,achieving high selectivity for C2+products is challenging for copper-based catalysts,as C–C coupling reactions proceed slowly.Herein,a surface modification strategy involving grafting long alkyl chains onto copper nanowires(Cu NWs)has been proposed to regulate the electronic structure of Cu surface,which facilitates*CO-*CO coupling in the CO_(2)RR.The hydrophobicity of the catalysts increases greatly after the introduction of long alkyl chains,therefore the hydrogen evolution reaction(HER)has been inhibited effectively.Such surface modification approach proves to be highly efficient and universal,with the Faradaic efficiency(FE)of C_(2)H_(4) up to 53%for the optimized Cu–SH catalyst,representing a significant enhancement compared to the pristine Cu NWs(30%).In-situ characterizations and theoretical calculations demonstrate that the different terminal groups of the grafted octadecyl chains can effectively regulate the charge density of Cu NWs interface and change the adsorption configuration of*CO intermediate.The top-adsorbed*CO intermediates(*COtop)on Cu–SH catalytic interface endow Cu–SH with the highest charge density,which effectively lowers the reaction energy barrier for*CO-*CO coupling,promoting the formation of the*OCCO intermediate,thereby enhancing the selectivity towards C_(2)H_(4).This study provides a promising method for designing efficient Cu-based catalysts with high catalytic activity and selectivity towards C2H4.
文摘Rice straw,a by-product of rice cultivation,is commonly disposed of through open-field burning,which contributes to air pollution and environmental degradation.This study aims to identify the key factors influencing farmers’decisions on rice straw management and to develop policy recommendations that encourage the sustainable utilization of rice straw within the supply chain.A mixed-methods approach was adopted,combining qualitative interviews with nine key informants and a quantitative survey of 585 rice farmers across Thailand.Multinomial Logit Regression(MLR)was employed to analyze farmers’preferences among four management options:burning,composting,animal feeding,and selling.The results reveal that membership in farmer groups,ownership of livestock,access to baling machinery,knowledge,and skills related to straw utilization,ease of field access,availability of storage facilities,engagement in integrated farming,and year-round access to baling services significantly increased the likelihood of choosing sustainable alternatives over the burning straw.These findings underscore the importance of both capacity-building and infrastructure in enabling sustainable practices.Based on these insights,the study proposes a multi-level policy framework to enhance the value creation of rice straw.National policies should focus on expanding access to machinery and supporting innovation,while local governments should facilitate farmer training and improve straw logistics.Strengthening farmer organizations and market connections is also crucial for scaling adoption.Overall,structural integration and stakeholder coordination are key to reducing straw burning and promoting sustainable resource use in rice-producing regions.
文摘The evolution of human societal systems rarely manifests qualitative leaps or revolutionary transformations.More commonly observed are subtle,cumulative evolutionary processes characterized by smooth transitions of incremental developments.Such evolutionary trajectories can generally be described through quantitative change patterns within societal systems.Yet,what constitutes sustainable development in human society?How might sustainable development be articulated or operationalized?The Three Chains Theory under the framework of System Exchange Theory provides a preliminary exploration and analysis of these questions,offering tentative interpretations.
基金funded by the 2022-2023 Australian Centre for International Agricultural Research(ACIAR)Alumni Research Support Facility(ARSF)programme:“Farmers’adaptive capacity and agricultural transformation in the Vietnamese Mekong Delta:understanding and supporting value chain engagement”the ACIAR-funded project“Farmer options for crops under saline conditions(FOCUS)in the Mekong River Delta,Vietnam”(SLaM/2018/144)to this study.
文摘Agricultural production(especially intensive rice production)is a primary income source for over 2.0×10^(7) people in the Vietnamese Mekong River Delta.However,adverse climate change impacts,socio-economic change,and high dependence on farm inputs for intensive production constrain the longer-term sustainability of rice systems.Government and agribusiness actors are encouraging more farmers to grow non-rice crops and supporting the upscaling of alternative crops to paddy rice.We used a qualitative approach to investigate the value chain characteristics,as well as constraints and opportunities of alternative crops via two case studies(baby corn and honeydew melon)in An Giang and Hau Giang provinces,Vietnam.Data collection involved focus group discussions with local farmers and interviews with farmers and industry experts.Thematic analysis was used to compile the findings,and the results were validated with local government staff.The baby corn value chain featured on-going and stable market demand(including value-addition)and better vertical coordination(e.g.,written contracts and financial support).The honeydew melon value chain featured positive relationships between farmers and traders despite less-developed vertical coordination.There are opportunities for value chain engagement through product quality certification,value-addition,and accessing high-value domestic and export markets.However,farmers require crop-specific and generic support from private and public sectors.Increased labour requirements and limited access to finance and credit limit value chain participation.Upscaling and marketing alternative crops can enhance farmer profitability and support non-farming agricultural business establishment,economic growth,and community development.Efficient value chains will be critical to ensure the adoption of alternative crops and development of crop-specific agribusiness models.These findings can inform policy-makers and change facilitators in designing targeted interventions to support the adoption of alternative crops in the study area as well as in Vietnam and globally.
