Multiple principal element alloys(MPEAs),also known as high-entropy alloys,have attracted significant attention because of their exceptional mechanical and thermal properties.A critical factor influencing these proper...Multiple principal element alloys(MPEAs),also known as high-entropy alloys,have attracted significant attention because of their exceptional mechanical and thermal properties.A critical factor influencing these properties is suggested to be the presence of chemical short-range order(SRO),characterized by specific atomic arrangements occurring more frequently than in a random distribution.Despite extensive efforts to elucidate SRO,particularly in face-centered cubic(fcc)3d transition metal-based MPEAs,several key aspects remain under debate:the conditions under which SRO forms,the reliability of characterization methods for detecting SRO,and its quantitative impact on mechanical performance.This review summarizes the challenges and unresolved issues in this emerging field,drawing comparisons with well-established research on SRO in binary alloys over the past few decades.Through this cross-system comparison,we aim to provide new insights into SRO from a comprehensive perspective.展开更多
In this paper we firstly select main factors relating to urbanization level of Xiantao District in Hubei Province by main element, then, make model of urbanization level by analysis of multiple liner regression, and l...In this paper we firstly select main factors relating to urbanization level of Xiantao District in Hubei Province by main element, then, make model of urbanization level by analysis of multiple liner regression, and lastly predict its urbanization level展开更多
The concurrent segregation of multiple solute elements at grain boundaries(GBs),also known as co-segregation,is a pervasive interfacial behavior that governs microstructural evolution and influences many properties of...The concurrent segregation of multiple solute elements at grain boundaries(GBs),also known as co-segregation,is a pervasive interfacial behavior that governs microstructural evolution and influences many properties of high-entropy alloys(HEAs).However,accurately predicting co-segregation behavior in HEAs is a challenging task due to the vast compositional space and complex interactions among multiple solute elements.In this paper,we developed a scalarization-based Bayesian optimization(SBO)framework integrated with high-throughput atomistic simulations to efficiently explore and optimize the large compositional space of CrMnFeCoNi HEAs for targeted co-segregation behavior and other desirable interfacial properties.Specifically,Thompson sampling is adopted to explore the input compositional space and identify HEA candidates representing two extremes:the strongest and weakest co-segregation of Cr and Mn at CrMnFeCoNi GBs.These SBO-predicted segregation extremes are subsequently validated by hybrid molecular dynamics/Monte Carlo simulations and first-principles calculations.Furthermore,electronic structure calculations demonstrate that the co-segregation of Cr and Mn can be ascribed to the hybridization of their d valence electrons promoted by the presence of Fe.While this SBO framework focuses on segregation behavior,it can be easily extended to optimize a wide range of interfacial properties in multicomponent systems.This study establishes a new paradigm for designing advanced HEAs through interfacial property optimization.展开更多
The current environmental flow assessment of Chinese rivers is thought to have three shortcomings: The first is that environmental flow requirements of reservoirs in dammed rivers are usually not explicitly considered...The current environmental flow assessment of Chinese rivers is thought to have three shortcomings: The first is that environmental flow requirements of reservoirs in dammed rivers are usually not explicitly considered; the second is that enough attentions have not been paid to the inherent links between flow regime and ecological processes; the third is that most studies focus on the variable range of merely one hydrological element such as discharge needed by riverine ecosystems. Here, first proposed is a holistic method for environmental flow assessment, the flow-ecological response relationship method that is suitable for large rivers with relatively abundant ecological data. Based on the conceptual models and quantitative relationships between flow and ecological response, this method comprehensively considers the ecological conservation requirements of both reservoir and its downstream reach. Then, it is applied to assessing the environmental flows of the Three Gorges Reservoir and its downstream reach by the following steps: 1) Construction of conceptual models of flow-ecological response; 2) identification of ecological targets of environmental flows and their key periods; 3) development of the quantitative relationships between hydrological indicators and ecological indictors; 4) preliminary assessment of environmental flow according to the tradeoff between ecological targets and water demands of human. The environmental flow hydrographs obtained have explicit ecological conservation targets, time schedule of achieving each target, and characteristics of multiple hydrological elements such as flow, water level, frequency, timing, duration and rate of change. The case study has tested the reasonability and feasibility of this method, and the results of this study are expected to provide technical support and decision reference for improving the operation of the Three Gorges-Gezhouba cascade reservoirs.展开更多
基金supported by the Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments,China(Grant No.22dz2260800)the Shanghai Science and Technology Committee,China(Grant No.22JC1410300).
文摘Multiple principal element alloys(MPEAs),also known as high-entropy alloys,have attracted significant attention because of their exceptional mechanical and thermal properties.A critical factor influencing these properties is suggested to be the presence of chemical short-range order(SRO),characterized by specific atomic arrangements occurring more frequently than in a random distribution.Despite extensive efforts to elucidate SRO,particularly in face-centered cubic(fcc)3d transition metal-based MPEAs,several key aspects remain under debate:the conditions under which SRO forms,the reliability of characterization methods for detecting SRO,and its quantitative impact on mechanical performance.This review summarizes the challenges and unresolved issues in this emerging field,drawing comparisons with well-established research on SRO in binary alloys over the past few decades.Through this cross-system comparison,we aim to provide new insights into SRO from a comprehensive perspective.
文摘In this paper we firstly select main factors relating to urbanization level of Xiantao District in Hubei Province by main element, then, make model of urbanization level by analysis of multiple liner regression, and lastly predict its urbanization level
基金support by the DOE Award DE-SC0025431The research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using NERSC award BES-ERCAP0031213This work was also supported by a user project at the Center for Nanophase Materials Sciences (CNMS), a US DOE Office of Science User Facility, operated at Oak Ridge National Laboratory. Computations used resources of the National Energy Research Scientific Computing Center (NERSC), a US DOE Office of Science User Facility using NERSC award BES-ERCAP0027465 and ERCAP0031261.
文摘The concurrent segregation of multiple solute elements at grain boundaries(GBs),also known as co-segregation,is a pervasive interfacial behavior that governs microstructural evolution and influences many properties of high-entropy alloys(HEAs).However,accurately predicting co-segregation behavior in HEAs is a challenging task due to the vast compositional space and complex interactions among multiple solute elements.In this paper,we developed a scalarization-based Bayesian optimization(SBO)framework integrated with high-throughput atomistic simulations to efficiently explore and optimize the large compositional space of CrMnFeCoNi HEAs for targeted co-segregation behavior and other desirable interfacial properties.Specifically,Thompson sampling is adopted to explore the input compositional space and identify HEA candidates representing two extremes:the strongest and weakest co-segregation of Cr and Mn at CrMnFeCoNi GBs.These SBO-predicted segregation extremes are subsequently validated by hybrid molecular dynamics/Monte Carlo simulations and first-principles calculations.Furthermore,electronic structure calculations demonstrate that the co-segregation of Cr and Mn can be ascribed to the hybridization of their d valence electrons promoted by the presence of Fe.While this SBO framework focuses on segregation behavior,it can be easily extended to optimize a wide range of interfacial properties in multicomponent systems.This study establishes a new paradigm for designing advanced HEAs through interfacial property optimization.
基金supported by the Ministry of Science and Technology of China (Grant Nos. 2012BAC06B01, 2012BAC06B04)
文摘The current environmental flow assessment of Chinese rivers is thought to have three shortcomings: The first is that environmental flow requirements of reservoirs in dammed rivers are usually not explicitly considered; the second is that enough attentions have not been paid to the inherent links between flow regime and ecological processes; the third is that most studies focus on the variable range of merely one hydrological element such as discharge needed by riverine ecosystems. Here, first proposed is a holistic method for environmental flow assessment, the flow-ecological response relationship method that is suitable for large rivers with relatively abundant ecological data. Based on the conceptual models and quantitative relationships between flow and ecological response, this method comprehensively considers the ecological conservation requirements of both reservoir and its downstream reach. Then, it is applied to assessing the environmental flows of the Three Gorges Reservoir and its downstream reach by the following steps: 1) Construction of conceptual models of flow-ecological response; 2) identification of ecological targets of environmental flows and their key periods; 3) development of the quantitative relationships between hydrological indicators and ecological indictors; 4) preliminary assessment of environmental flow according to the tradeoff between ecological targets and water demands of human. The environmental flow hydrographs obtained have explicit ecological conservation targets, time schedule of achieving each target, and characteristics of multiple hydrological elements such as flow, water level, frequency, timing, duration and rate of change. The case study has tested the reasonability and feasibility of this method, and the results of this study are expected to provide technical support and decision reference for improving the operation of the Three Gorges-Gezhouba cascade reservoirs.
