Thanks to its abundant reserves,relatively high energy density,and low reduction potential,potassium ion batteries(PIBs)have a high potential for large-scale energy storage applications.Due to the large radius of pota...Thanks to its abundant reserves,relatively high energy density,and low reduction potential,potassium ion batteries(PIBs)have a high potential for large-scale energy storage applications.Due to the large radius of potassium ions,most conventional anode materials undergo severe volume expansion,making it difficult to achieve stable and reversible energy storage.Therefore,developing high-performance anode materials is one of the critical factors in developing PIBs.In this sense,antimony(Sb)-based anode materials with high theoretical capacity and safe reaction potentials have a broad potential for application in PIBs.However,overcoming the rapid capacity decay induced by the large radius of potassium ions is still an issue that needs to be focused on.This paper reviews the latest research on different types of Sb-based anode materials and provides an in-depth analysis of their optimization strategies.We focus on material selection,structural design,and storage mechanisms to develop a detailed description of the material.In addition,the current challenges still faced by Sb-based anode materials are summarized,and some further optimization strategies have been added.We hope to provide some insights for researchers developing Sb-based anode materials for next-generation advanced PIBs.展开更多
Selecting proper descriptors(also known feature selection,FS)is key in the process of establishing mechanical properties prediction model of hot-rolled microalloyed steels by using machine learning(ML)algorithm.FS met...Selecting proper descriptors(also known feature selection,FS)is key in the process of establishing mechanical properties prediction model of hot-rolled microalloyed steels by using machine learning(ML)algorithm.FS methods based on data-driving can reduce the redundancy of data features and improve the prediction accuracy of mechanical properties.Based on the collected data of hot-rolled microalloyed steels,the association rules are used to mine the correlation information between the data.High-quality feature subsets are selected by the proposed FS method(FS method based on genetic algorithm embedding,GAMIC).Compared with the common FS method,it is shown on dataset that GAMIC selects feature subsets more appropriately.Six different ML algorithms are trained and tested for mechanical properties prediction.The result shows that the root-mean-square error of yield strength,tensile strength and elongation based on limit gradient enhancement(XGBoost)algorithm is 21.95 MPa,20.85 MPa and 1.96%,the correlation coefficient(R^(2))is 0.969,0.968 and 0.830,and the mean absolute error is 16.84 MPa,15.83 MPa and 1.48%,respectively,showing the best prediction performance.Finally,SHapley Additive exPlanation is used to further explore the influence of feature variables on mechanical properties.GAMIC feature selection method proposed is universal,which provides a basis for the development of high-precision mechanical property prediction model.展开更多
Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of ...Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of hydrogen sulfide(SOH_(2)S) to elemental sulfur(S) has emerged as a sustainable and environmentally friendly solution.Due to its unique properties,iron oxide has been extensively investigated as a catalyst for SOH_(2)S;however,rapid deactivation has remained a significant drawback.The causes of iron oxide-based catalysts deactivation mechanisms in SOH_(2)S,including sulfur or sulfate deposition,the transformation of iron species,sintering and excessive oxygen vacancy formation,and active site loss,are thoroughly examined in this review.By focusing on the deactivation mechanisms,this review aims to provide valuable insights into enhancing the stability and efficiency of iron-based catalysts for SOH_(2)S.展开更多
Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction m...Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction mechanism and phase evolution of the low-temperature selective chlorination process of Nd-Fe-B sludge are not clear.In this paper,we systematically investigated the lowtemperature selective chlorination process of Nd-Fe-B sludge with NH4Cl by combining thermokinetic theoretical calculations and experiments,and revealed its reaction mechanism.The phase evolution during chlorination was determined by X-ray diffraction(XRD),scanning electron microscopy(SEM)and ene rgy-dispersive X-ray spectroscopy(EDS)characterization as well as co mputational analysis of the phase stability diagram of the M-O-Cl system.To determine the optimum chlorination conditions,the effects of chlorinating agent dosage,reaction temperature and reaction time on the reaction were investigated.The results show that the rare earth components in Nd-Fe-B sludge are selectively chlorinated to RECl3and the formation of REOCl is avoided in the temperature range of 300-420℃,while the iron components are preferentially oxidized to Fe2O3.The selective chlorination reaction is consistent with the unreacted shrinking core model,and the rate-controlling step of the reaction is the internal diffusion process of NH4Cl through the transition layer of the reactant product to the surface of the Nd-Fe-B sludge.The complete chlorination of REEs is successfully achieved and 99.8%of REEs are selectively extracted into the leaching solution under optimal chlorination conditions(300℃,2.5 times of stoichiometric amount,4 h).展开更多
Selective laser melting,a predominant additive manufacturing technology for fabricating geometrically complex components,faces signifcant challenges when processing high-performance Ni-based superalloys containing ele...Selective laser melting,a predominant additive manufacturing technology for fabricating geometrically complex components,faces signifcant challenges when processing high-performance Ni-based superalloys containing elevated Al and Ti concentrations(typically>6 wt%),particularly regarding micro-cracking susceptibility.In this study,we demonstrate the successful fabrication of a novel crack-free Ni-based superalloy with 6.4 wt%(Al+Ti)content via optimized energy density,systematically investigating its microstructure,defects,and mechanical properties.Process parameter analysis revealed that insufcient energy densities led to unmolten pores,while excessively high energy densities caused keyhole formation.With an optimal energy density of 51.1 J/mm3,the crack-free superalloy exhibited exceptional mechanical properties:room temperature tensile strength of 1130 MPa with 36%elongation and elevated-temperature strength reaching 1198 MPa at 750℃.This strength enhancement correlates with the precipitation of nanoscaleγ′phases(mean size:31.56 nm)during high temperature.Furthermore,the mechanism of crack suppression is explained from multiple aspects,including energy density,grain structure,grain boundary characteristics,and the distribution of secondary phases.The absence of low-melting-point eutectic phases and brittle phases during the printing process is also explained from the perspective of alloy composition.These fndings provide a comprehensive framework for alloy design and process optimization in additive manufacturing of defect-resistant Ni-based superalloys.展开更多
In order to obtain high-density dual-scale ceramic particles(8.5 wt.%SiC+1.5 wt.%TiC)reinforced Al-Mg Sc-Zr composites with uniform microstructure,50 nm TiC and 7μm SiC particles were pre-dispersed into 15−53μm alum...In order to obtain high-density dual-scale ceramic particles(8.5 wt.%SiC+1.5 wt.%TiC)reinforced Al-Mg Sc-Zr composites with uniform microstructure,50 nm TiC and 7μm SiC particles were pre-dispersed into 15−53μm aluminum alloy powders by low-speed ball milling and mechanical mixing technology,respectively.Then,the effects of laser energy density,power and scanning rate on the density of the composites were investigated based on selective laser melting(SLM)technology.The effect of micron-sized SiC and nano-sized TiC particles on solidification structure,mechanical properties and fracture behaviors of the composites was revealed and analyzed in detail.Interfacial reaction and phase variations in the composites with varying reinforced particles were emphatically considered.Results showed that SiC-TiC particles could significantly improve forming quality and density of the SLMed composites,and the optimal relative density was up to 100%.In the process of laser melting,a strong chemical reaction occurs between SiC and aluminum matrix,and micron-scale acicular Al_(4)SiC_(4) bands were formed in situ.There was no interfacial reaction between TiC particles and aluminum matrix.TiC/Al semi-coherent interface had good bonding strength.Pinning effect of TiC particles in grain boundaries could prevent the equiaxial crystals from growing and transforming into columnar crystals,resulting in grain refinement.The optimal ultimate tensile strength(UTS),yield strength(YS),elongation(EL)and elastic modulus of the SiC-TiC/Al-Mg-Sc-Zr composite were~394 MPa,~262 MPa,~8.2%and~86 GPa,respectively.The fracture behavior of the composites included ductile fracture of Al matrix and brittle cleavage fracture of Al_(4)SiC_(4) phases.A large number of cross-distributed acicular Al_(4)SiC_(4) bands were the main factors leading to premature failure and fracture of SiC-TiC/Al-Mg-Sc-Zr composites.展开更多
With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade recla...With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade reclaimed water,produce energy,and preserve valuable nutrients from municipal wastewater.However,the selectivity of these osmotic membranes towards ammonia nitrogen,a major component in municipal wastewater and anaerobic effluent,remains unsatisfactory due to its similar polarity and hydraulic radius to water molecules.Therefore,enhancing the ammonia nitrogen rejection of osmotic membranes is imperative to maximize the quality of reclaimed water and minimize the loss of ammonia nitrogen resources.Unfortunately,the current understanding of the mapping relationship between ammonia nitrogen transmembrane diffusion and the micro/nano-structure of osmotic membranes is not systematic,making precise optimization of the membranes challenging.Hence,this review comprehensively analyzed the diffusion behavior of ammonia nitrogen through osmotic membranes to lay the foundation for targeted regulation of membrane fine structure.Initially,the desire for ammonia/ammonium-rejecting membranes was highlighted by introducing current and promising osmotic membrane-based applications in municipal wastewater reclamation processes.Subsequently,the connection between the micro/nano-structure of osmotic membranes and the transmembrane diffusion behavior of ammonia nitrogen was explored by analyzing the effects of membrane characteristics on ammonia nitrogen transport using the DSPM-DE model.Finally,precise methods for modifying membranes to enhance ammonia nitrogen rejection were proposed.This review aims to offer theoretical insights guiding the development of RO and FO membranes with superior ammonia nitrogen rejection for efficient reclamation of municipal wastewater.展开更多
Because of an unfortunate mistake during the production of this article,the Acknowledgements have been omitted.The Acknowledgements are added as follows:Sasan YAZDANI would like to thank the Scientific and Technologic...Because of an unfortunate mistake during the production of this article,the Acknowledgements have been omitted.The Acknowledgements are added as follows:Sasan YAZDANI would like to thank the Scientific and Technological Research Council of Turkey(TÜB˙ITAK)for receiving financial support for this work through the 2221 Fellowship Program for Visiting Scientists and Scientists on Sabbatical Leave(Grant ID:E 21514107-115.02-228864).Sasan YAZDANI also expresses his gratitude to Sahand University of Technology for granting him sabbatical leave to facilitate the completion of this research.展开更多
Al−3.51Mg−0.42Mn−0.76Sc−0.40Zr(wt.%)alloy was prepared by selective laser melting(SLM)method.The mechanical properties and microstructure of the alloy after annealing at 300℃or 325℃for 6 h were studied.The tensile s...Al−3.51Mg−0.42Mn−0.76Sc−0.40Zr(wt.%)alloy was prepared by selective laser melting(SLM)method.The mechanical properties and microstructure of the alloy after annealing at 300℃or 325℃for 6 h were studied.The tensile strength,yield strength and elongation of the SLM alloy were 339 MPa,213 MPa and 24%,respectively.After annealing at 300℃for 6 h,the tensile and yield strength of the alloy were increased to 518 MPa and 505 MPa,respectively,and the elongation decreased to 13%.After annealing at 325℃for 6 h,the yield strength of the alloy was reduced to 483 MPa.The grain size of the alloy after annealing at 300℃and 325℃did not grow significantly,but the segregation of Mg element was significantly reduced.Nanoscale Al3(Sc,Zr)phase was precipitated from the alloy matrix,and its average size increased with the increase of annealing temperature.Therefore,the strength improvement of the annealed SLM aluminum alloy was mainly attributed to the precipitation strengthening of Al3(Sc,Zr),and the strengthening mechanism was mainly dislocation cutting mechanism.When the annealing temperature was too high,the coarsening of Al3(Sc,Zr)particles caused the strength to decrease.展开更多
In order to increase the processability and process window of the selective laser melting(SLM)-fabricated Al−Mn−Mg−Er−Zr alloy,a novel Si-modified Al−Mn−Mg−Er−Zr alloy was designed.The effect of Si alloying on the sur...In order to increase the processability and process window of the selective laser melting(SLM)-fabricated Al−Mn−Mg−Er−Zr alloy,a novel Si-modified Al−Mn−Mg−Er−Zr alloy was designed.The effect of Si alloying on the surface quality,processability,microstructure,and mechanical properties of the SLM-fabricated alloy was studied.The results showed that introducing Si into the Al−Mn−Mg−Er−Zr alloy prevented balling and keyhole formation,refined the grain size,and reduced the solidification temperature,which eliminated cracks and increased the processability and process window of the alloy.The maximum relative density of the SLM-fabricated Si/Al−Mn−Mg−Er−Zr alloy reached 99.6%.The yield strength and ultimate tensile strength of the alloy were(371±7)MPa and(518±6)MPa,respectively.These values were higher than those of the SLM-fabricated Al−Mn−Mg−Er−Zr and other Sc-free Al−Mg-based alloys.展开更多
Probiotics participate in various physiological activities and contribute to body health.However,their viability and bioefficacy are adversely affected by gastrointestinal harsh conditions,such as gastric acid,bile sa...Probiotics participate in various physiological activities and contribute to body health.However,their viability and bioefficacy are adversely affected by gastrointestinal harsh conditions,such as gastric acid,bile salts and various enzymes.Fortunately,encapsulation based on various nanomaterials shows tremendous potential to protect probiotics.In this review,we introduced some novel encapsulation technologies involving nanomaterials in view of predesigned stability and viability,selective adhesion,smart release and colonization,and efficacy exertion of encapsulated probiotics.Furthermore,the interactions between encapsulated probiotics and the gastrointestinal tract were summarized and analyzed,with highlighting the regulatory mechanisms of encapsulated probiotics on intestinal mechanical barrier,chemical barrier,biological barrier and immune barrier.This review would benefit the food and pharmaceutical industries in preparation and utilization of multifunctional encapsulated probiotics.展开更多
The relationships between the selective laser melting(SLM)processing parameters including laser power,scanning speed and hatch space,the relative density,the microstructure,and resulting mechanical properties of Ti-6A...The relationships between the selective laser melting(SLM)processing parameters including laser power,scanning speed and hatch space,the relative density,the microstructure,and resulting mechanical properties of Ti-6Al-2Zr-1Mo-1V alloy were investigated in this work.The result shows that laser power acts a dominant role in determining the relative density in comparison with scanning speed and hatch space.The optimal SLM process window for fabricating relative density>99%samples is located in the energy density range of 34.72 J·mm^(-3)to 52.08 J·mm^(-3),where the laser power range is between 125 W and 175 W.An upward trend is found in the micro-hardness as the energy density is increased.The optimum SLM processing parameters of Ti-6Al-2Zr-1Mo-1V alloy are:laser power of 150 W,scanning speed of 1,600 mm·s^(-1),hatch space of 0.08 mm,and layer thickness of 0.03 mm.The highest ultimate tensile strength,yield strength,and ductility under the optimum processing parameter are achieved,which are 1,205 MPa,1,099 MPa,and 8%,respectively.The results of this study can be used to guide SLM production Ti-6Al-2Zr-1Mo-1V alloy parts.展开更多
Defect formation is a common problem in selective laser melting (SLM). This paper provides a review of defect formation mechanisms in SLM. It sum- marizes the recent research outcomes on defect findings and classifi...Defect formation is a common problem in selective laser melting (SLM). This paper provides a review of defect formation mechanisms in SLM. It sum- marizes the recent research outcomes on defect findings and classification, analyzes formation mechanisms of the common defects, such as porosities, incomplete fusion holes, and cracks. The paper discusses the effect of the process parameters on defect formation and the impact of defect formation on the mechanical properties of a fabri- cated part. Based on the discussion, the paper proposes strategies for defect suppression and control in SLM.展开更多
The test selection and optimization (TSO) can improve the abilities of fault diagnosis, prognosis and health-state evalua- tion for prognostics and health management (PHM) systems. Traditionally, TSO mainly focuse...The test selection and optimization (TSO) can improve the abilities of fault diagnosis, prognosis and health-state evalua- tion for prognostics and health management (PHM) systems. Traditionally, TSO mainly focuses on fault detection and isolation, but they cannot provide an effective guide for the design for testability (DFT) to improve the PHM performance level. To solve the problem, a model of TSO for PHM systems is proposed. Firstly, through integrating the characteristics of fault severity and propa- gation time, and analyzing the test timing and sensitivity, a testability model based on failure evolution mechanism model (FEMM) for PHM systems is built up. This model describes the fault evolution- test dependency using the fault-symptom parameter matrix and symptom parameter-test matrix. Secondly, a novel method of in- herent testability analysis for PHM systems is developed based on the above information. Having completed the analysis, a TSO model, whose objective is to maximize fault trackability and mini- mize the test cost, is proposed through inherent testability analysis results, and an adaptive simulated annealing genetic algorithm (ASAGA) is introduced to solve the TSO problem. Finally, a case of a centrifugal pump system is used to verify the feasibility and effectiveness of the proposed models and methods. The results show that the proposed technology is important for PHM systems to select and optimize the test set in order to improve their performance level.展开更多
The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth concentrate.In an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by apply...The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth concentrate.In an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by applying selective mechanical activation was proposed.First,regarding the key minerals affecting the leaching selectivity of Ca to REs,the differences in the mechanical activation behaviors of CaF_(2) and REFCO_(3) were studied,and we find that the lattice strain of CaF_(2) increases from 0.21%to 0.42%,whereas that of REFCO_(3) increases from 0.31%to 0.40%.Notably,CaF_(2) demonstrates a larger lattice strain than REFCO_(3),indicating greater mechanical activation energy storage and higher leaching activity.Next,the HCl leaching process was studied.A significant leaching selectivity of Ca to REs,from 21.6 to 35.1,is achieved through mechanical activation.The Ca leaching rate reaches 80.7%when the RE loss is 2.3%in the activated sample.This study provides an novel approach for achieving selective extraction of specific components via mechanical activation pretreatment.展开更多
Deep learning models have been shown to have great advantages in answer selection tasks.The existing models,which employ encoder-decoder recurrent neural network(RNN),have been demonstrated to be effective.However,the...Deep learning models have been shown to have great advantages in answer selection tasks.The existing models,which employ encoder-decoder recurrent neural network(RNN),have been demonstrated to be effective.However,the traditional RNN-based models still suffer from limitations such as 1)high-dimensional data representation in natural language processing and 2)biased attentive weights for subsequent words in traditional time series models.In this study,a new answer selection model is proposed based on the Bidirectional Long Short-Term Memory(Bi-LSTM)and attention mechanism.The proposed model is able to generate the more effective question-answer pair representation.Experiments on a question answering dataset that includes information from multiple fields show the great advantages of our proposed model.Specifically,we achieve a maximum improvement of 3.8%over the classical LSTM model in terms of mean average precision.展开更多
In this work,selective laser melting(SLM)process is used to prepare the AlNi6TiZr alloy.By analyzing the printing quality and mechanical properties of the printed specimens with different process parameters,the SLM fo...In this work,selective laser melting(SLM)process is used to prepare the AlNi6TiZr alloy.By analyzing the printing quality and mechanical properties of the printed specimens with different process parameters,the SLM forming window of AlNi6TiZr is obtained.The relative density of the sample printed with 270 W-1100 mm/s(laser energy density:82 J/mm3)reaches 99.7%,exhibiting excellent mechanical properties(yield strength(YS):421.7 MPa;ultimate tensile strength(UTS):480.4 MPa).After an aging treatment of 325 ℃-12 h,the YS and UTS of the sample increased to 494 MPa and 550.7 MPa,respectively.Adding Ni,Ti,and Zr components promoted the generation of multi-phase precipitates in the Al alloy and improved the synergistic strengthening effect of multi-phases.The hard-shell structure(HSS)formed by the Al_(3)Ni phase at the grain boundary significantly strengthened the grain boundary strength.The precipitated Al_(3)(Ti,Zr)phases at the grain boundaries prevent grain growth and dislocation movement.The Al_(3)Ni and Al_(3)(Ti,Zr)phases have good thermal stability that can still maintain excellent enhancement effects at high temperature.AlNi6TiZr alloy has great application prospects in medium and high-temperature environments.展开更多
Although selective laser trabeculoplasty(SLT)is a recognized method for the treatment of glaucoma,the exact changes in the target tissue and mechanism for its intraocular pressure lowing effect are still unclear.The p...Although selective laser trabeculoplasty(SLT)is a recognized method for the treatment of glaucoma,the exact changes in the target tissue and mechanism for its intraocular pressure lowing effect are still unclear.The purpose of this review is to summarize the potential mechanisms of SLT on trabecular meshwork both in vivo and in vitro,so as to reveal the potential mechanism of SLT.SLT may induce immune or inflammatory response in trabecular meshwork(TM)induced by possible oxidative damage etc,and remodel extracellular matrix.It may also induce monocytes to aggregate in TM tissue,increase Schlemm’s canal(SC)cell conductivity,disintegrate cell junction and promote permeability through autocrine and paracrine forms.This provides a theoretical basis for SLT treatment in glaucoma.展开更多
The development of bio-adsorbents with highly selective immobilization properties for specific heavy metals is a great challenge,but has important application value.Biogenic whewellite(BW)with high selectivity for Pb(...The development of bio-adsorbents with highly selective immobilization properties for specific heavy metals is a great challenge,but has important application value.Biogenic whewellite(BW)with high selectivity for Pb(Ⅱ)was synthesized by mineral microbial transformation.The selective immobilization properties and mechanism of BW for Pb(Ⅱ)were analyzed by combining mineral characterization technology and batch adsorption research methods.The results indicated that BW can efficiently and selectively immobilize Pb(Ⅱ)in single or composite heavy metal adsorption solutions,and the immobilized Pb(Ⅱ)is difficult to desorb.BW undergoes monolayer adsorption on Pb(Ⅱ),Qmax≈1073.17 mg/g.The immobilization of Pb(Ⅱ)by BW is a physico-chemical adsorption process with spontaneous heat absorption and an accompanying increase in entropy.In addition,the sequestration of Pb(Ⅱ)by BW remains around 756.99 mg/g even at p H=1.The excellent selective immobilization properties of BW for Pb(Ⅱ)are closely related to its smaller Ksp,electrostatic repulsion effect,organic-inorganic composite structure,acid resistance and the formation of Pb(Ⅱ)oxalate.This study provides beneficial information about the recycling of lead in acidic lead-containing wastewater and composite heavy metal contaminated water bodies.展开更多
Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile...Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22209057)the Guangzhou Basic and Applied Basic Research Foundation(No.2024A04J0839)。
文摘Thanks to its abundant reserves,relatively high energy density,and low reduction potential,potassium ion batteries(PIBs)have a high potential for large-scale energy storage applications.Due to the large radius of potassium ions,most conventional anode materials undergo severe volume expansion,making it difficult to achieve stable and reversible energy storage.Therefore,developing high-performance anode materials is one of the critical factors in developing PIBs.In this sense,antimony(Sb)-based anode materials with high theoretical capacity and safe reaction potentials have a broad potential for application in PIBs.However,overcoming the rapid capacity decay induced by the large radius of potassium ions is still an issue that needs to be focused on.This paper reviews the latest research on different types of Sb-based anode materials and provides an in-depth analysis of their optimization strategies.We focus on material selection,structural design,and storage mechanisms to develop a detailed description of the material.In addition,the current challenges still faced by Sb-based anode materials are summarized,and some further optimization strategies have been added.We hope to provide some insights for researchers developing Sb-based anode materials for next-generation advanced PIBs.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3702404)the National Natural Science Foundation of China(Grant No.52104370)+4 种基金the Reviving-Liaoning Excellence Plan(XLYC2203186)Science and Technology Special Projects of Liaoning Province(Grant No.2022JH25/10200001)the Postdoctoral Research Fund for Northeastern(Grant No.20210203)Independent Projects of Basic Scientific Research(ZZ2021005)CITIC Niobium Steel Development Award Fund(2022-M1824).
文摘Selecting proper descriptors(also known feature selection,FS)is key in the process of establishing mechanical properties prediction model of hot-rolled microalloyed steels by using machine learning(ML)algorithm.FS methods based on data-driving can reduce the redundancy of data features and improve the prediction accuracy of mechanical properties.Based on the collected data of hot-rolled microalloyed steels,the association rules are used to mine the correlation information between the data.High-quality feature subsets are selected by the proposed FS method(FS method based on genetic algorithm embedding,GAMIC).Compared with the common FS method,it is shown on dataset that GAMIC selects feature subsets more appropriately.Six different ML algorithms are trained and tested for mechanical properties prediction.The result shows that the root-mean-square error of yield strength,tensile strength and elongation based on limit gradient enhancement(XGBoost)algorithm is 21.95 MPa,20.85 MPa and 1.96%,the correlation coefficient(R^(2))is 0.969,0.968 and 0.830,and the mean absolute error is 16.84 MPa,15.83 MPa and 1.48%,respectively,showing the best prediction performance.Finally,SHapley Additive exPlanation is used to further explore the influence of feature variables on mechanical properties.GAMIC feature selection method proposed is universal,which provides a basis for the development of high-precision mechanical property prediction model.
基金supported by Thailand Science Research and Innovation Fund Chulalongkorn University,Thailand(IND66210014)。
文摘Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of hydrogen sulfide(SOH_(2)S) to elemental sulfur(S) has emerged as a sustainable and environmentally friendly solution.Due to its unique properties,iron oxide has been extensively investigated as a catalyst for SOH_(2)S;however,rapid deactivation has remained a significant drawback.The causes of iron oxide-based catalysts deactivation mechanisms in SOH_(2)S,including sulfur or sulfate deposition,the transformation of iron species,sintering and excessive oxygen vacancy formation,and active site loss,are thoroughly examined in this review.By focusing on the deactivation mechanisms,this review aims to provide valuable insights into enhancing the stability and efficiency of iron-based catalysts for SOH_(2)S.
基金Project supported by the National Natural Science Foundation of China(52261037,52401251)Key Research Project of Jiangxi Province(20203ABC28W006)+2 种基金the Research Fund of Key Laboratory of Rare Earths,Chinese Academy of SciencesKey Laboratory of Ionic Rare Earth Re sources and Environment,Ministry of Natural Resources of the People's Republic of China(2022IRERE302)the Ganzhou Science and Technology Innovation Empowerment Youth"Jie bang Gua shuai"Project。
文摘Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction mechanism and phase evolution of the low-temperature selective chlorination process of Nd-Fe-B sludge are not clear.In this paper,we systematically investigated the lowtemperature selective chlorination process of Nd-Fe-B sludge with NH4Cl by combining thermokinetic theoretical calculations and experiments,and revealed its reaction mechanism.The phase evolution during chlorination was determined by X-ray diffraction(XRD),scanning electron microscopy(SEM)and ene rgy-dispersive X-ray spectroscopy(EDS)characterization as well as co mputational analysis of the phase stability diagram of the M-O-Cl system.To determine the optimum chlorination conditions,the effects of chlorinating agent dosage,reaction temperature and reaction time on the reaction were investigated.The results show that the rare earth components in Nd-Fe-B sludge are selectively chlorinated to RECl3and the formation of REOCl is avoided in the temperature range of 300-420℃,while the iron components are preferentially oxidized to Fe2O3.The selective chlorination reaction is consistent with the unreacted shrinking core model,and the rate-controlling step of the reaction is the internal diffusion process of NH4Cl through the transition layer of the reactant product to the surface of the Nd-Fe-B sludge.The complete chlorination of REEs is successfully achieved and 99.8%of REEs are selectively extracted into the leaching solution under optimal chlorination conditions(300℃,2.5 times of stoichiometric amount,4 h).
基金supported by the National Natural Science Foundation of China(Nos.51775140 and 52232004)supported by the Shenzhen Science and Technology Plan(KJZD20230923113900001).
文摘Selective laser melting,a predominant additive manufacturing technology for fabricating geometrically complex components,faces signifcant challenges when processing high-performance Ni-based superalloys containing elevated Al and Ti concentrations(typically>6 wt%),particularly regarding micro-cracking susceptibility.In this study,we demonstrate the successful fabrication of a novel crack-free Ni-based superalloy with 6.4 wt%(Al+Ti)content via optimized energy density,systematically investigating its microstructure,defects,and mechanical properties.Process parameter analysis revealed that insufcient energy densities led to unmolten pores,while excessively high energy densities caused keyhole formation.With an optimal energy density of 51.1 J/mm3,the crack-free superalloy exhibited exceptional mechanical properties:room temperature tensile strength of 1130 MPa with 36%elongation and elevated-temperature strength reaching 1198 MPa at 750℃.This strength enhancement correlates with the precipitation of nanoscaleγ′phases(mean size:31.56 nm)during high temperature.Furthermore,the mechanism of crack suppression is explained from multiple aspects,including energy density,grain structure,grain boundary characteristics,and the distribution of secondary phases.The absence of low-melting-point eutectic phases and brittle phases during the printing process is also explained from the perspective of alloy composition.These fndings provide a comprehensive framework for alloy design and process optimization in additive manufacturing of defect-resistant Ni-based superalloys.
基金Project(2022J318)supported by the Natural Science Foundation of Ningbo,ChinaProject(2021A1515110525)supported by the Guangdong Basic and Applied Basic Research Foundation,ChinaProject(2022QN05023)supported by the Inner Mongolia Natural Science Foundation Youth Project,China。
文摘In order to obtain high-density dual-scale ceramic particles(8.5 wt.%SiC+1.5 wt.%TiC)reinforced Al-Mg Sc-Zr composites with uniform microstructure,50 nm TiC and 7μm SiC particles were pre-dispersed into 15−53μm aluminum alloy powders by low-speed ball milling and mechanical mixing technology,respectively.Then,the effects of laser energy density,power and scanning rate on the density of the composites were investigated based on selective laser melting(SLM)technology.The effect of micron-sized SiC and nano-sized TiC particles on solidification structure,mechanical properties and fracture behaviors of the composites was revealed and analyzed in detail.Interfacial reaction and phase variations in the composites with varying reinforced particles were emphatically considered.Results showed that SiC-TiC particles could significantly improve forming quality and density of the SLMed composites,and the optimal relative density was up to 100%.In the process of laser melting,a strong chemical reaction occurs between SiC and aluminum matrix,and micron-scale acicular Al_(4)SiC_(4) bands were formed in situ.There was no interfacial reaction between TiC particles and aluminum matrix.TiC/Al semi-coherent interface had good bonding strength.Pinning effect of TiC particles in grain boundaries could prevent the equiaxial crystals from growing and transforming into columnar crystals,resulting in grain refinement.The optimal ultimate tensile strength(UTS),yield strength(YS),elongation(EL)and elastic modulus of the SiC-TiC/Al-Mg-Sc-Zr composite were~394 MPa,~262 MPa,~8.2%and~86 GPa,respectively.The fracture behavior of the composites included ductile fracture of Al matrix and brittle cleavage fracture of Al_(4)SiC_(4) phases.A large number of cross-distributed acicular Al_(4)SiC_(4) bands were the main factors leading to premature failure and fracture of SiC-TiC/Al-Mg-Sc-Zr composites.
基金supported by National Natural Science Foundation of China(No.52200051)Harbin Institute of Technology(No.HC202236)Outstanding Youth Fund of Heilongjiang Natural Science Foundation(No.YQ2023E021)。
文摘With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade reclaimed water,produce energy,and preserve valuable nutrients from municipal wastewater.However,the selectivity of these osmotic membranes towards ammonia nitrogen,a major component in municipal wastewater and anaerobic effluent,remains unsatisfactory due to its similar polarity and hydraulic radius to water molecules.Therefore,enhancing the ammonia nitrogen rejection of osmotic membranes is imperative to maximize the quality of reclaimed water and minimize the loss of ammonia nitrogen resources.Unfortunately,the current understanding of the mapping relationship between ammonia nitrogen transmembrane diffusion and the micro/nano-structure of osmotic membranes is not systematic,making precise optimization of the membranes challenging.Hence,this review comprehensively analyzed the diffusion behavior of ammonia nitrogen through osmotic membranes to lay the foundation for targeted regulation of membrane fine structure.Initially,the desire for ammonia/ammonium-rejecting membranes was highlighted by introducing current and promising osmotic membrane-based applications in municipal wastewater reclamation processes.Subsequently,the connection between the micro/nano-structure of osmotic membranes and the transmembrane diffusion behavior of ammonia nitrogen was explored by analyzing the effects of membrane characteristics on ammonia nitrogen transport using the DSPM-DE model.Finally,precise methods for modifying membranes to enhance ammonia nitrogen rejection were proposed.This review aims to offer theoretical insights guiding the development of RO and FO membranes with superior ammonia nitrogen rejection for efficient reclamation of municipal wastewater.
文摘Because of an unfortunate mistake during the production of this article,the Acknowledgements have been omitted.The Acknowledgements are added as follows:Sasan YAZDANI would like to thank the Scientific and Technological Research Council of Turkey(TÜB˙ITAK)for receiving financial support for this work through the 2221 Fellowship Program for Visiting Scientists and Scientists on Sabbatical Leave(Grant ID:E 21514107-115.02-228864).Sasan YAZDANI also expresses his gratitude to Sahand University of Technology for granting him sabbatical leave to facilitate the completion of this research.
基金financially supported by the National Key Research and Development Program of China(No.2018YFB2001801)State’s Key Project of Research and Development Plan(No.2021YFC1910505)the Key Research and Development Program of Guangdong Province,China(No.2020B010186002)。
文摘Al−3.51Mg−0.42Mn−0.76Sc−0.40Zr(wt.%)alloy was prepared by selective laser melting(SLM)method.The mechanical properties and microstructure of the alloy after annealing at 300℃or 325℃for 6 h were studied.The tensile strength,yield strength and elongation of the SLM alloy were 339 MPa,213 MPa and 24%,respectively.After annealing at 300℃for 6 h,the tensile and yield strength of the alloy were increased to 518 MPa and 505 MPa,respectively,and the elongation decreased to 13%.After annealing at 325℃for 6 h,the yield strength of the alloy was reduced to 483 MPa.The grain size of the alloy after annealing at 300℃and 325℃did not grow significantly,but the segregation of Mg element was significantly reduced.Nanoscale Al3(Sc,Zr)phase was precipitated from the alloy matrix,and its average size increased with the increase of annealing temperature.Therefore,the strength improvement of the annealed SLM aluminum alloy was mainly attributed to the precipitation strengthening of Al3(Sc,Zr),and the strengthening mechanism was mainly dislocation cutting mechanism.When the annealing temperature was too high,the coarsening of Al3(Sc,Zr)particles caused the strength to decrease.
基金the National Natural Science Foundation of China(Nos.51801079,52001140)the Portugal National Funds through FCT Project(No.2021.04115).
文摘In order to increase the processability and process window of the selective laser melting(SLM)-fabricated Al−Mn−Mg−Er−Zr alloy,a novel Si-modified Al−Mn−Mg−Er−Zr alloy was designed.The effect of Si alloying on the surface quality,processability,microstructure,and mechanical properties of the SLM-fabricated alloy was studied.The results showed that introducing Si into the Al−Mn−Mg−Er−Zr alloy prevented balling and keyhole formation,refined the grain size,and reduced the solidification temperature,which eliminated cracks and increased the processability and process window of the alloy.The maximum relative density of the SLM-fabricated Si/Al−Mn−Mg−Er−Zr alloy reached 99.6%.The yield strength and ultimate tensile strength of the alloy were(371±7)MPa and(518±6)MPa,respectively.These values were higher than those of the SLM-fabricated Al−Mn−Mg−Er−Zr and other Sc-free Al−Mg-based alloys.
基金supported by the National Key Research and Development Program(2019YFC1606704)the Key Research and Development Program of Shaanxi Province(2022NY-013)+1 种基金National Natural Science Foundation of China(31801653)the Natural Science Foundation of Shaanxi Province(2019JQ-722).
文摘Probiotics participate in various physiological activities and contribute to body health.However,their viability and bioefficacy are adversely affected by gastrointestinal harsh conditions,such as gastric acid,bile salts and various enzymes.Fortunately,encapsulation based on various nanomaterials shows tremendous potential to protect probiotics.In this review,we introduced some novel encapsulation technologies involving nanomaterials in view of predesigned stability and viability,selective adhesion,smart release and colonization,and efficacy exertion of encapsulated probiotics.Furthermore,the interactions between encapsulated probiotics and the gastrointestinal tract were summarized and analyzed,with highlighting the regulatory mechanisms of encapsulated probiotics on intestinal mechanical barrier,chemical barrier,biological barrier and immune barrier.This review would benefit the food and pharmaceutical industries in preparation and utilization of multifunctional encapsulated probiotics.
基金supported by Liaoning Doctoral Research Start-up Fund project(Grant No.2023-BS-215).
文摘The relationships between the selective laser melting(SLM)processing parameters including laser power,scanning speed and hatch space,the relative density,the microstructure,and resulting mechanical properties of Ti-6Al-2Zr-1Mo-1V alloy were investigated in this work.The result shows that laser power acts a dominant role in determining the relative density in comparison with scanning speed and hatch space.The optimal SLM process window for fabricating relative density>99%samples is located in the energy density range of 34.72 J·mm^(-3)to 52.08 J·mm^(-3),where the laser power range is between 125 W and 175 W.An upward trend is found in the micro-hardness as the energy density is increased.The optimum SLM processing parameters of Ti-6Al-2Zr-1Mo-1V alloy are:laser power of 150 W,scanning speed of 1,600 mm·s^(-1),hatch space of 0.08 mm,and layer thickness of 0.03 mm.The highest ultimate tensile strength,yield strength,and ductility under the optimum processing parameter are achieved,which are 1,205 MPa,1,099 MPa,and 8%,respectively.The results of this study can be used to guide SLM production Ti-6Al-2Zr-1Mo-1V alloy parts.
基金Supported by National Natural Science Foundation of China(Grant No.51605077)Science Challenge Project(Grant No.CKY2016212A506-0101)Science Fund for Creative Research Groups of NSFC(Grant No.51621064)
文摘Defect formation is a common problem in selective laser melting (SLM). This paper provides a review of defect formation mechanisms in SLM. It sum- marizes the recent research outcomes on defect findings and classification, analyzes formation mechanisms of the common defects, such as porosities, incomplete fusion holes, and cracks. The paper discusses the effect of the process parameters on defect formation and the impact of defect formation on the mechanical properties of a fabri- cated part. Based on the discussion, the paper proposes strategies for defect suppression and control in SLM.
基金supported by the National Natural Science Foundation of China(51175502)
文摘The test selection and optimization (TSO) can improve the abilities of fault diagnosis, prognosis and health-state evalua- tion for prognostics and health management (PHM) systems. Traditionally, TSO mainly focuses on fault detection and isolation, but they cannot provide an effective guide for the design for testability (DFT) to improve the PHM performance level. To solve the problem, a model of TSO for PHM systems is proposed. Firstly, through integrating the characteristics of fault severity and propa- gation time, and analyzing the test timing and sensitivity, a testability model based on failure evolution mechanism model (FEMM) for PHM systems is built up. This model describes the fault evolution- test dependency using the fault-symptom parameter matrix and symptom parameter-test matrix. Secondly, a novel method of in- herent testability analysis for PHM systems is developed based on the above information. Having completed the analysis, a TSO model, whose objective is to maximize fault trackability and mini- mize the test cost, is proposed through inherent testability analysis results, and an adaptive simulated annealing genetic algorithm (ASAGA) is introduced to solve the TSO problem. Finally, a case of a centrifugal pump system is used to verify the feasibility and effectiveness of the proposed models and methods. The results show that the proposed technology is important for PHM systems to select and optimize the test set in order to improve their performance level.
基金Project supported by the National Natural Science Foundation of China(52004252)Natural Science Foundation ofHenan Province(222300420548)Strategic Research and Consulting Project of Chinese Academy of Engineering(2022-XBZD-07)。
文摘The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth concentrate.In an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by applying selective mechanical activation was proposed.First,regarding the key minerals affecting the leaching selectivity of Ca to REs,the differences in the mechanical activation behaviors of CaF_(2) and REFCO_(3) were studied,and we find that the lattice strain of CaF_(2) increases from 0.21%to 0.42%,whereas that of REFCO_(3) increases from 0.31%to 0.40%.Notably,CaF_(2) demonstrates a larger lattice strain than REFCO_(3),indicating greater mechanical activation energy storage and higher leaching activity.Next,the HCl leaching process was studied.A significant leaching selectivity of Ca to REs,from 21.6 to 35.1,is achieved through mechanical activation.The Ca leaching rate reaches 80.7%when the RE loss is 2.3%in the activated sample.This study provides an novel approach for achieving selective extraction of specific components via mechanical activation pretreatment.
基金This work was supported in part by the National Natural Science Foundation of China under Grant 61572326,and Grant 61802258the Natural Science Foundation of Shanghai under Grant 18ZR1428300the Shanghai Committee of Science and Technology under Grant 17070502800 and Grant 16JC1403000.
文摘Deep learning models have been shown to have great advantages in answer selection tasks.The existing models,which employ encoder-decoder recurrent neural network(RNN),have been demonstrated to be effective.However,the traditional RNN-based models still suffer from limitations such as 1)high-dimensional data representation in natural language processing and 2)biased attentive weights for subsequent words in traditional time series models.In this study,a new answer selection model is proposed based on the Bidirectional Long Short-Term Memory(Bi-LSTM)and attention mechanism.The proposed model is able to generate the more effective question-answer pair representation.Experiments on a question answering dataset that includes information from multiple fields show the great advantages of our proposed model.Specifically,we achieve a maximum improvement of 3.8%over the classical LSTM model in terms of mean average precision.
基金Post Graduate Innovation Funding Project of Hebei Province(No.CXZZSS2023041)Hebei Natural Science Foundation of China(No.E2021203138)Special Project for Local Science and Technology Development Guided by the Central Government of Hebei Province(236Z1805G).
文摘In this work,selective laser melting(SLM)process is used to prepare the AlNi6TiZr alloy.By analyzing the printing quality and mechanical properties of the printed specimens with different process parameters,the SLM forming window of AlNi6TiZr is obtained.The relative density of the sample printed with 270 W-1100 mm/s(laser energy density:82 J/mm3)reaches 99.7%,exhibiting excellent mechanical properties(yield strength(YS):421.7 MPa;ultimate tensile strength(UTS):480.4 MPa).After an aging treatment of 325 ℃-12 h,the YS and UTS of the sample increased to 494 MPa and 550.7 MPa,respectively.Adding Ni,Ti,and Zr components promoted the generation of multi-phase precipitates in the Al alloy and improved the synergistic strengthening effect of multi-phases.The hard-shell structure(HSS)formed by the Al_(3)Ni phase at the grain boundary significantly strengthened the grain boundary strength.The precipitated Al_(3)(Ti,Zr)phases at the grain boundaries prevent grain growth and dislocation movement.The Al_(3)Ni and Al_(3)(Ti,Zr)phases have good thermal stability that can still maintain excellent enhancement effects at high temperature.AlNi6TiZr alloy has great application prospects in medium and high-temperature environments.
文摘Although selective laser trabeculoplasty(SLT)is a recognized method for the treatment of glaucoma,the exact changes in the target tissue and mechanism for its intraocular pressure lowing effect are still unclear.The purpose of this review is to summarize the potential mechanisms of SLT on trabecular meshwork both in vivo and in vitro,so as to reveal the potential mechanism of SLT.SLT may induce immune or inflammatory response in trabecular meshwork(TM)induced by possible oxidative damage etc,and remodel extracellular matrix.It may also induce monocytes to aggregate in TM tissue,increase Schlemm’s canal(SC)cell conductivity,disintegrate cell junction and promote permeability through autocrine and paracrine forms.This provides a theoretical basis for SLT treatment in glaucoma.
基金supported by the Interdisciplinary Project of the Nanjing Normal University (No.164320H1847)the National Natural Science Foundation of China (No.41772360)。
文摘The development of bio-adsorbents with highly selective immobilization properties for specific heavy metals is a great challenge,but has important application value.Biogenic whewellite(BW)with high selectivity for Pb(Ⅱ)was synthesized by mineral microbial transformation.The selective immobilization properties and mechanism of BW for Pb(Ⅱ)were analyzed by combining mineral characterization technology and batch adsorption research methods.The results indicated that BW can efficiently and selectively immobilize Pb(Ⅱ)in single or composite heavy metal adsorption solutions,and the immobilized Pb(Ⅱ)is difficult to desorb.BW undergoes monolayer adsorption on Pb(Ⅱ),Qmax≈1073.17 mg/g.The immobilization of Pb(Ⅱ)by BW is a physico-chemical adsorption process with spontaneous heat absorption and an accompanying increase in entropy.In addition,the sequestration of Pb(Ⅱ)by BW remains around 756.99 mg/g even at p H=1.The excellent selective immobilization properties of BW for Pb(Ⅱ)are closely related to its smaller Ksp,electrostatic repulsion effect,organic-inorganic composite structure,acid resistance and the formation of Pb(Ⅱ)oxalate.This study provides beneficial information about the recycling of lead in acidic lead-containing wastewater and composite heavy metal contaminated water bodies.
文摘Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.