In this study,we examine the dynamics and microphysical structures of a deep compact thunderstorm event driving cloud-to-ground(CG)lightning over the Nanjing area located within the Yangtze-Huai River Basin(YHRB)durin...In this study,we examine the dynamics and microphysical structures of a deep compact thunderstorm event driving cloud-to-ground(CG)lightning over the Nanjing area located within the Yangtze-Huai River Basin(YHRB)during the monsoon break period.The microphysical structures combined with the dynamics in the glaciated,mixed-phase,and warm-phase layers during the formative,intensifying,and mature stages of the thunderstorm were first investigated using C-band polarimetric radar and CG lightning observations.The results show that the mature phase of the thunderstorm produced a local cold pool,which collided with a southerly warm wind,resulting in a strong updraft.The strong updraft favored the lifting of raindrops to the mixed-phase region to form abundant supercooled liquid water and graupel.From the formative stage to the developing stage and further to the mature stage,increased ZH-and reduced ZDR-values within the mixed-phase region are found,especially within the strong updraft region(>5 m s^(-1)).This phenomenon suggests that supercooled raindrops evolved into large hydrometeors(graupel and hail),indicative of a strong riming process.The signatures within this region are consistent with a favorable environment for thunderstorm electrification and generate the most frequent lightning during the thunderstorm life cycle.展开更多
Transforming nanoscale and bulk metals into single atoms is crucial for the scalable production of single-atom catalysts(SACs),especially during pyrolysis.However,conventional equilibrium heating approaches often requ...Transforming nanoscale and bulk metals into single atoms is crucial for the scalable production of single-atom catalysts(SACs),especially during pyrolysis.However,conventional equilibrium heating approaches often require prolonged operation to decompose metal aggregates,leading to tedious and time-consuming procedures for synthesizing SACs.In this study,we introduce high-temperature shock(HTS)strategy to enhance metal atomization,achieving the direct transformation of bulk copper foil into single atoms in just 0.5 s at 1700 K.The HTS-produced Cu catalyst demonstrates a high content of 0.54 wt.%,comparable to those achieved by commonly reported top-down strategies,indicating that the HTS method provides a compelling alternative for synthesizing Cu SACs from bulk Cu precursors.Structural analysis confirmed the synthesis of a Cu-N-C SAC with a Cu-N_(4) coordination environment.This Cu-N_(4) structure shows excellent catalytic performance for nitrite reduction to ammonia,achieving over 90% Faradaic efficiency across the entire working potential range and an ammonia production rate of up to 11.12 mg·cm^(-2)·h^(-1) at -1.2 V vs.reversible hydrogen electrode(RHE),surpassing other reported Cu-based electrocatalysts.Furthermore,ab initio molecular dynamics(AIMD)simulations reveal that transient high temperatures not only promote the formation of thermodynamically favorable Cu-N bonds but also prevent excessive sintering and aggregation of metal atoms.展开更多
Mangroves are crucial to the ecological security of the Earth and human well-being.Their management,conservation,and restoration are of great importance and necessitate the support of spatio-temporal information and m...Mangroves are crucial to the ecological security of the Earth and human well-being.Their management,conservation,and restoration are of great importance and necessitate the support of spatio-temporal information and multidisciplinary knowledge such as biology and ecology.Traditional knowledge services such as plant atlas provide illustrated textual knowledge of mangroves.However,this kind of service is oriented to information retrieval and is incapable of effectively mining and utilizing fragmented knowledge from multi-source heterogeneous data,facing the problem of“massive data,rare knowledge”.Knowledge graphs are capable of extracting,organizing,and fusing the knowledge contained in massive data into semantic networks that can be understood and computed by computers.They provide a solution for the realization of intelligent knowledge services.Focusing on the urgent need for mangrove knowledge acquisition,formal representation,and intelligent services,this paper proposes a research prospect on mangrove knowledge graphs and knowledge services.We first analyze the similarities and differences between various domain-specific concepts of Tupu.On this basis,we define the mangrove knowledge graph as a large-scale knowledge base that integrates multi-disciplinary knowledge and spatio-temporal information with mangrove ecosystems as the core.Then,we propose a research framework for mangrove knowledge services that can realize the transformation from multi-modal data to intelligent knowledge services,including multiple research levels such as ubiquitous data sensing and aggregation,knowledge organization and graph construction,and intelligent mangrove knowledge services.Subsequently,the methods and workflow for constructing mangrove knowledge graphs are introduced.Finally,we discuss the challenges and possible future directions of mangrove knowledge services in the smart era,including the construction of a mangrove knowledge system that integrates the domain-specific characteristics and spatio-temporal features of mangroves,the exploration of knowledge extraction and fusion methods supported by large language models,and the development of intelligent knowledge applications for typical scenarios.展开更多
基金primarily supported by the National Natural Science Foundation of China(Grant Nos.42025501,41805025,42175005,and 61827901)the National Key R&D Program of China(2022YFC3003905)+5 种基金the National Key Laboratory on Electromagnetic Environmental Effects and Electro-optical Engineering(NO.JCKYS61422062101)the Meteorological Union Fund of the National Natural Science Foundation of China(U2142203)the Foundation of Jiangsu Provincial Meteorological Bureau(KM202308)The Open Grants of China Meteorological Administration Radar Meteorology Key Laboratory(2023LRMB04)S&T Development Fund of NJIAS(KJF202307)the Open Research Program of the State Key Laboratory of Severe Weather(2022LASW-A01)。
文摘In this study,we examine the dynamics and microphysical structures of a deep compact thunderstorm event driving cloud-to-ground(CG)lightning over the Nanjing area located within the Yangtze-Huai River Basin(YHRB)during the monsoon break period.The microphysical structures combined with the dynamics in the glaciated,mixed-phase,and warm-phase layers during the formative,intensifying,and mature stages of the thunderstorm were first investigated using C-band polarimetric radar and CG lightning observations.The results show that the mature phase of the thunderstorm produced a local cold pool,which collided with a southerly warm wind,resulting in a strong updraft.The strong updraft favored the lifting of raindrops to the mixed-phase region to form abundant supercooled liquid water and graupel.From the formative stage to the developing stage and further to the mature stage,increased ZH-and reduced ZDR-values within the mixed-phase region are found,especially within the strong updraft region(>5 m s^(-1)).This phenomenon suggests that supercooled raindrops evolved into large hydrometeors(graupel and hail),indicative of a strong riming process.The signatures within this region are consistent with a favorable environment for thunderstorm electrification and generate the most frequent lightning during the thunderstorm life cycle.
基金the National Natural Science Foundation of China(Nos.22222305,22402164,and 22021001)the Fundamental Research Funds for the Central Universities(No.20720220013).
文摘Transforming nanoscale and bulk metals into single atoms is crucial for the scalable production of single-atom catalysts(SACs),especially during pyrolysis.However,conventional equilibrium heating approaches often require prolonged operation to decompose metal aggregates,leading to tedious and time-consuming procedures for synthesizing SACs.In this study,we introduce high-temperature shock(HTS)strategy to enhance metal atomization,achieving the direct transformation of bulk copper foil into single atoms in just 0.5 s at 1700 K.The HTS-produced Cu catalyst demonstrates a high content of 0.54 wt.%,comparable to those achieved by commonly reported top-down strategies,indicating that the HTS method provides a compelling alternative for synthesizing Cu SACs from bulk Cu precursors.Structural analysis confirmed the synthesis of a Cu-N-C SAC with a Cu-N_(4) coordination environment.This Cu-N_(4) structure shows excellent catalytic performance for nitrite reduction to ammonia,achieving over 90% Faradaic efficiency across the entire working potential range and an ammonia production rate of up to 11.12 mg·cm^(-2)·h^(-1) at -1.2 V vs.reversible hydrogen electrode(RHE),surpassing other reported Cu-based electrocatalysts.Furthermore,ab initio molecular dynamics(AIMD)simulations reveal that transient high temperatures not only promote the formation of thermodynamically favorable Cu-N bonds but also prevent excessive sintering and aggregation of metal atoms.
基金supported by the National Natural Science Foundation of China(Grant No.42301536)the National Key Research and Development Program of China(Grant No.2022YFF0711602)the GDAS’Project of Science and Technology Development(Grant Nos.2022GDASZH-2022010202,2022GDASZH2022020402-01&2022GDASZH-2022010111)。
文摘Mangroves are crucial to the ecological security of the Earth and human well-being.Their management,conservation,and restoration are of great importance and necessitate the support of spatio-temporal information and multidisciplinary knowledge such as biology and ecology.Traditional knowledge services such as plant atlas provide illustrated textual knowledge of mangroves.However,this kind of service is oriented to information retrieval and is incapable of effectively mining and utilizing fragmented knowledge from multi-source heterogeneous data,facing the problem of“massive data,rare knowledge”.Knowledge graphs are capable of extracting,organizing,and fusing the knowledge contained in massive data into semantic networks that can be understood and computed by computers.They provide a solution for the realization of intelligent knowledge services.Focusing on the urgent need for mangrove knowledge acquisition,formal representation,and intelligent services,this paper proposes a research prospect on mangrove knowledge graphs and knowledge services.We first analyze the similarities and differences between various domain-specific concepts of Tupu.On this basis,we define the mangrove knowledge graph as a large-scale knowledge base that integrates multi-disciplinary knowledge and spatio-temporal information with mangrove ecosystems as the core.Then,we propose a research framework for mangrove knowledge services that can realize the transformation from multi-modal data to intelligent knowledge services,including multiple research levels such as ubiquitous data sensing and aggregation,knowledge organization and graph construction,and intelligent mangrove knowledge services.Subsequently,the methods and workflow for constructing mangrove knowledge graphs are introduced.Finally,we discuss the challenges and possible future directions of mangrove knowledge services in the smart era,including the construction of a mangrove knowledge system that integrates the domain-specific characteristics and spatio-temporal features of mangroves,the exploration of knowledge extraction and fusion methods supported by large language models,and the development of intelligent knowledge applications for typical scenarios.
