1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(inclu...1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(including Archean-Proterozoic migmatite,gneiss,schists and Pan-African “Older Granites”),Mesozoic alkaline ring complexes(“Younger Granites”) and sedimentary basins(Yang QD et al.,2023;Fig.1a).“Older Granites” are part of the Pan-African mobile belt;“Younger Granites” has significant peralkaline characteristics.“Younger Granites” has a wide distribution in the north-central region of Nigeria,including areas such as Kano,Jos-Bauchi,Mada,and Nasarawa,and the emplacement age gradually decreases from north to south from 213 Ma(Dutse complex) to 141 Ma(Afu complex)(Amuda AK et al.,2021).展开更多
Nickel-rich LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(NCM)cathodes,pivotal for high-energy-density lithium-ion batteries,face severe challenges from surface residual lithium compounds and hydrofluoric acid(HF)-induced degradation...Nickel-rich LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(NCM)cathodes,pivotal for high-energy-density lithium-ion batteries,face severe challenges from surface residual lithium compounds and hydrofluoric acid(HF)-induced degradation.These issues accelerate capacity fading,exacerbate interfacial polarization,and compromise safety.To address these issues,we proposed a scalable CeF_(3)/H_(3)BO_(3)hybrid coating strategy for LiNi_(0.82)Co_(0.12)Mn_(0.06)O_(2)cathodes.The CeF_(3)nanoparticles served as a robust physical barrier,effectively scavenging HF,while the LiBO_(2)layer derived from H_(3)BO_(3)eliminated residual Li_(2)CO_(3)through chemical conversion and established rapid Li^(+)transport pathways.Dynamic B-O bond reorganization enabled self-repair of coating defects,synergistically suppressing interfacial polarization and maintaining structural integrity.Electrochemical evaluations demonstrated that the hybridcoated cathode achieves 94%capacity retention after 200 cycles at 1C(2.8-4.3 V),significantly outperforming the pristine NCM(56.3%).Additionally,the modified cathode exhibits enhanced air stability,with suppressed H_(2)O/CO_(2)infiltration,and delivers 80%capacity retention after 1000 cycles in practical pouch cells.This work provides a costeffective and industrially viable solution to simultaneously mitigate HF corrosion,residual lithium accumulation,and cathode-electrolyte interphase instability,paving the way for durable high-energy-density batteries.展开更多
The lithium-ion batteries(LIBs)have been widely equipped in electric/hybrid electric vehicles(EVs/HEVs)and the portable electronics due to their excellent electrochemical performances.However,a large number of retired...The lithium-ion batteries(LIBs)have been widely equipped in electric/hybrid electric vehicles(EVs/HEVs)and the portable electronics due to their excellent electrochemical performances.However,a large number of retired LIBs that consist of toxic substances(e.g.,heavy metals,electrolytes)and valuable metals(e.g.,Li,Co)will inevitably flow into the waste stream,and their incineration or landfill treatment will cause severe risks to ecosystem and human beings.The sustainable and efficient treatment or recycling of valuable resources from spent LIBs should be fully recognized for environmental and resource security.As one of the most important processes for spent LIBs recycling,the pretreatment is an indispensable step,which is directly related to the subsequent metal extraction and separation processes.Although considerable progresses have been made regarding the pretreatment technologies,there are few summarized reports concerning critical processes of spent LIBs recycling,especially combination of currently available recycling technologies with industrialized applications during pretreatments.Therefore,comprehensive review of the current prevailing pretreatment technologies in laboratory to existing scale-up applications is quite necessary to reveal cutting-edge development in the field of pretreatment.In this review,the current pretreatment technologies are systematically categorized and introduced,along with critical discussions.This review focused on the various options for pretreatment processes itself,instead of general spent LIBs recycling technologies without the focused topics that have been sophisticatedly reviewed by previous studies.Here,the deactivation,discharge,dismantling,separation,liberation of active material and electrolyte treatment have been summarized with the in-depth discussion of the technology development and current status of each category.Finally,current states of industrial development are also reviewed and discussed for the development of efficient and environmentally friendly recycling technologies for future applications.This review tends to present a focused topic concerning the pretreatment of spent LIBs to potential readers with a comprehensive illustration of the development on both cutting-edge technologies and scale-up applications.展开更多
Ethereum blockchain is a new internetware with tens of millions of smart contracts running on it.Different from general programs,smart contracts are decentralized,tamper-resistant and permanently running.Moreover,to a...Ethereum blockchain is a new internetware with tens of millions of smart contracts running on it.Different from general programs,smart contracts are decentralized,tamper-resistant and permanently running.Moreover,to avoid resource abuse,Ethereum charges users for deploying and invoking smart contracts according to the size of contract and the operations executed by contracts.It is necessary to optimize smart contracts to save money.However,since developers are not familiar with the operating environment of smart contracts(i.e.,Ethereum virtual machine)or do not pay attention to resource consumption during development,there are many optimization opportunities for smart contracts.To fill this gap,this paper defines six gas-inefficient patterns from more than 25,000 posts and proposes an optimization approach at the source code level to let users know clearly where the contract is optimized.To evaluate the prevalence and economic benefits of gas-inefficient patterns,this paper conducts an empirical study on more than 160,000 real smart contracts.The promising experimental results demonstrate that 52.75%of contracts contain at least one gas-inefficient pattern proposed in this paper.If these patterns are removed from the contract,at least 0.30 can be saved per contract.展开更多
With the growing requirements of web applications,web components are developed to package the implementation of commonly-used features for reuse.In some cases,the developer may want to reuse some features which cannot...With the growing requirements of web applications,web components are developed to package the implementation of commonly-used features for reuse.In some cases,the developer may want to reuse some features which cannot be customized by the component’s APIs.He/she has to extract the implementation by hand.It is labor-intensive and error-prone.Considering the widely-used test cases which can be useful to specify the software features,a test-driven approach is proposed to extract the implementation of the desired features in web components.The satisfaction of the user^requirements is transformed into the passing rate of user-specified test cases.In this way,the quality of the extraction result can be evaluated automatically.Meanwhile,a record/replay-based GUI test generation method is proposed to ensure that the extraction result has the correct GUI appearance.To extract the feature implementation,a hierarchical genetic algorithm is proposed to find the code snippet that can pass all the tests and has the approximate smallest size.We compare our method with two existing feature extraction methods.The result shows that our method can extract the correct implementation with the minimum size.A human-subject study is conducted to show the effectiveness and weaknesses of our method in helping users extract the features.展开更多
Commit messages are important complementary information used in understanding code changes. To address message scarcity, some work is proposed for automatically generating commit messages. However, most of these appro...Commit messages are important complementary information used in understanding code changes. To address message scarcity, some work is proposed for automatically generating commit messages. However, most of these approaches focus on generating summary of the changed software entities at the superficial level, without considering the intent behind the code changes (e.g., the existing approaches cannot generate such message:"fixing 'null' pointer exception"). Considering developers often describe the intent behind the code change when writing the messages, we propose ChangeDoc, an approach to reuse existing messages in version control systems for automatical commit message generation. Our approach includes syntax, semantic, pre-syntax, and pre-semantic similarities. For a given commit without messages, it is able to discover its most similar past commit from a large commit repository, and recommend its message as the message of the given commit. Our repository contains half a million commits that were collected from SourceForge. We evaluate our approach on the commits from 10 projects. The results show that 21.5% of the recommended messages by ChangeDoc can be directly used without modification, and 62.8% require minor modifications. In order to evaluate the quality of the commit messages recommended by ChangeDoc, we performed two empirical studies involving a total of 40 participants (10 professional developers and 30 students). The results indicate that the recommended messages are very good approximations of the ones written by developers and often include important intent information that is not included in the messages generated by other tools.展开更多
基金funded by the projects of Tianjin North China Geological Exploration Bureau (HK2023–B01,HK2022–B08)China Geological Survey (DD20230576,DD20201152)。
文摘1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(including Archean-Proterozoic migmatite,gneiss,schists and Pan-African “Older Granites”),Mesozoic alkaline ring complexes(“Younger Granites”) and sedimentary basins(Yang QD et al.,2023;Fig.1a).“Older Granites” are part of the Pan-African mobile belt;“Younger Granites” has significant peralkaline characteristics.“Younger Granites” has a wide distribution in the north-central region of Nigeria,including areas such as Kano,Jos-Bauchi,Mada,and Nasarawa,and the emplacement age gradually decreases from north to south from 213 Ma(Dutse complex) to 141 Ma(Afu complex)(Amuda AK et al.,2021).
基金financially supported by the National Key Research and Development Program(No.2022YFC3900905)the National Natural Science Foundation of China(No.52234001)the Science and Technology Planning Project of Hunan Province(No.2018TP1017)
文摘Nickel-rich LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(NCM)cathodes,pivotal for high-energy-density lithium-ion batteries,face severe challenges from surface residual lithium compounds and hydrofluoric acid(HF)-induced degradation.These issues accelerate capacity fading,exacerbate interfacial polarization,and compromise safety.To address these issues,we proposed a scalable CeF_(3)/H_(3)BO_(3)hybrid coating strategy for LiNi_(0.82)Co_(0.12)Mn_(0.06)O_(2)cathodes.The CeF_(3)nanoparticles served as a robust physical barrier,effectively scavenging HF,while the LiBO_(2)layer derived from H_(3)BO_(3)eliminated residual Li_(2)CO_(3)through chemical conversion and established rapid Li^(+)transport pathways.Dynamic B-O bond reorganization enabled self-repair of coating defects,synergistically suppressing interfacial polarization and maintaining structural integrity.Electrochemical evaluations demonstrated that the hybridcoated cathode achieves 94%capacity retention after 200 cycles at 1C(2.8-4.3 V),significantly outperforming the pristine NCM(56.3%).Additionally,the modified cathode exhibits enhanced air stability,with suppressed H_(2)O/CO_(2)infiltration,and delivers 80%capacity retention after 1000 cycles in practical pouch cells.This work provides a costeffective and industrially viable solution to simultaneously mitigate HF corrosion,residual lithium accumulation,and cathode-electrolyte interphase instability,paving the way for durable high-energy-density batteries.
基金financially supported by the National Natural Science Foundation of China(Nos.52074177 and 52174391)Hunan Provincial Science and Technology Plan,China(No.2017TP1001)。
文摘The lithium-ion batteries(LIBs)have been widely equipped in electric/hybrid electric vehicles(EVs/HEVs)and the portable electronics due to their excellent electrochemical performances.However,a large number of retired LIBs that consist of toxic substances(e.g.,heavy metals,electrolytes)and valuable metals(e.g.,Li,Co)will inevitably flow into the waste stream,and their incineration or landfill treatment will cause severe risks to ecosystem and human beings.The sustainable and efficient treatment or recycling of valuable resources from spent LIBs should be fully recognized for environmental and resource security.As one of the most important processes for spent LIBs recycling,the pretreatment is an indispensable step,which is directly related to the subsequent metal extraction and separation processes.Although considerable progresses have been made regarding the pretreatment technologies,there are few summarized reports concerning critical processes of spent LIBs recycling,especially combination of currently available recycling technologies with industrialized applications during pretreatments.Therefore,comprehensive review of the current prevailing pretreatment technologies in laboratory to existing scale-up applications is quite necessary to reveal cutting-edge development in the field of pretreatment.In this review,the current pretreatment technologies are systematically categorized and introduced,along with critical discussions.This review focused on the various options for pretreatment processes itself,instead of general spent LIBs recycling technologies without the focused topics that have been sophisticatedly reviewed by previous studies.Here,the deactivation,discharge,dismantling,separation,liberation of active material and electrolyte treatment have been summarized with the in-depth discussion of the technology development and current status of each category.Finally,current states of industrial development are also reviewed and discussed for the development of efficient and environmentally friendly recycling technologies for future applications.This review tends to present a focused topic concerning the pretreatment of spent LIBs to potential readers with a comprehensive illustration of the development on both cutting-edge technologies and scale-up applications.
基金supported by the Key-Area Research and Development Program of Guangdong Province of China under Grant No.2020B010164002the National Natural Science Foundation of China under Grant No.62032025.
文摘Ethereum blockchain is a new internetware with tens of millions of smart contracts running on it.Different from general programs,smart contracts are decentralized,tamper-resistant and permanently running.Moreover,to avoid resource abuse,Ethereum charges users for deploying and invoking smart contracts according to the size of contract and the operations executed by contracts.It is necessary to optimize smart contracts to save money.However,since developers are not familiar with the operating environment of smart contracts(i.e.,Ethereum virtual machine)or do not pay attention to resource consumption during development,there are many optimization opportunities for smart contracts.To fill this gap,this paper defines six gas-inefficient patterns from more than 25,000 posts and proposes an optimization approach at the source code level to let users know clearly where the contract is optimized.To evaluate the prevalence and economic benefits of gas-inefficient patterns,this paper conducts an empirical study on more than 160,000 real smart contracts.The promising experimental results demonstrate that 52.75%of contracts contain at least one gas-inefficient pattern proposed in this paper.If these patterns are removed from the contract,at least 0.30 can be saved per contract.
基金supported by the Key-Area Research and Development Program of Guangdong Province under Grant No.2020B010165001the National Natural Science Foundation of China under Grant No.61976061Guangdong Basic and Applied Basic Research Foundation under Grant No.2020A1515010973.
文摘With the growing requirements of web applications,web components are developed to package the implementation of commonly-used features for reuse.In some cases,the developer may want to reuse some features which cannot be customized by the component’s APIs.He/she has to extract the implementation by hand.It is labor-intensive and error-prone.Considering the widely-used test cases which can be useful to specify the software features,a test-driven approach is proposed to extract the implementation of the desired features in web components.The satisfaction of the user^requirements is transformed into the passing rate of user-specified test cases.In this way,the quality of the extraction result can be evaluated automatically.Meanwhile,a record/replay-based GUI test generation method is proposed to ensure that the extraction result has the correct GUI appearance.To extract the feature implementation,a hierarchical genetic algorithm is proposed to find the code snippet that can pass all the tests and has the approximate smallest size.We compare our method with two existing feature extraction methods.The result shows that our method can extract the correct implementation with the minimum size.A human-subject study is conducted to show the effectiveness and weaknesses of our method in helping users extract the features.
基金This work was(partially)supported by the Key-Area Research and Development Program of Guangdong Province of China under Grant No.2020B010164002the National Natural Science Foundation of China under Grant Nos.61902441,61722214 and 61976061+2 种基金the China Postdoctoral Science Foundation under Grant No.2018M640855the Fundamental Research Funds for the Central Universities of China under Grant Nos.20wkpy06 and 20lgpy129the Opening Project of Guangdong Key Laboratory of Big Data Analysis and Processing under Grant No.202003.
文摘Commit messages are important complementary information used in understanding code changes. To address message scarcity, some work is proposed for automatically generating commit messages. However, most of these approaches focus on generating summary of the changed software entities at the superficial level, without considering the intent behind the code changes (e.g., the existing approaches cannot generate such message:"fixing 'null' pointer exception"). Considering developers often describe the intent behind the code change when writing the messages, we propose ChangeDoc, an approach to reuse existing messages in version control systems for automatical commit message generation. Our approach includes syntax, semantic, pre-syntax, and pre-semantic similarities. For a given commit without messages, it is able to discover its most similar past commit from a large commit repository, and recommend its message as the message of the given commit. Our repository contains half a million commits that were collected from SourceForge. We evaluate our approach on the commits from 10 projects. The results show that 21.5% of the recommended messages by ChangeDoc can be directly used without modification, and 62.8% require minor modifications. In order to evaluate the quality of the commit messages recommended by ChangeDoc, we performed two empirical studies involving a total of 40 participants (10 professional developers and 30 students). The results indicate that the recommended messages are very good approximations of the ones written by developers and often include important intent information that is not included in the messages generated by other tools.
