Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durabili...Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durability,and corrosion resistance.These metals have body-centered cubic crystal structure,characterized by limited slip systems and impeded dislocation motion,resulting in significant low-temperature brittleness,which poses challenges for the conventional processing.Additive manufacturing technique provides an innovative approach,enabling the production of intricate parts without molds,which significantly improves the efficiency of material usage.This review provides a comprehensive overview of the advancements in additive manufacturing techniques for the production of refractory metals,such as W,Ta,Mo,and Nb,particularly the laser powder bed fusion.In this review,the influence mechanisms of key process parameters(laser power,scan strategy,and powder characteristics)on the evolution of material microstructure,the formation of metallurgical defects,and mechanical properties were discussed.Generally,optimizing powder characteristics,such as sphericity,implementing substrate preheating,and formulating alloying strategies can significantly improve the densification and crack resistance of manufactured parts.Meanwhile,strictly controlling the oxygen impurity content and optimizing the energy density input are also the key factors to achieve the simultaneous improvement in strength and ductility of refractory metals.Although additive manufacturing technique provides an innovative solution for processing refractory metals,critical issues,such as residual stress control,microstructure and performance anisotropy,and process stability,still need to be addressed.This review not only provides a theoretical basis for the additive manufacturing of high-performance refractory metals,but also proposes forward-looking directions for their industrial application.展开更多
Vitamin D deficiency(VDD)represents a significant nutritional concern among children and adolescents.The estimated prevalence of VDD in China is 46.8%in this population^([1]).VDD during childhood and adolescence has b...Vitamin D deficiency(VDD)represents a significant nutritional concern among children and adolescents.The estimated prevalence of VDD in China is 46.8%in this population^([1]).VDD during childhood and adolescence has been associated with the onset of various conditions,including acute respiratory infections,asthma,atopic dermatitis,and food allergies^([2]).Multiple factors,including age,sun exposure,adiposity,and genetics,influence vitamin D levels^([2,3]).Increasing attention has been directed toward understanding the environmental determinants that may influence vitamin D status.Given the potential of metallic pollutants to disrupt endocrine function and their ubiquity in the environment,investigating the effects of metal exposure on human vitamin D status,particularly in vulnerable populations,is imperative.展开更多
The surge in environmental pollution in recent years driven by numerous pollutants has necessitated the search for efficient removal methods.Phytoremediation is an eco-friendly technique that provides multiple benefit...The surge in environmental pollution in recent years driven by numerous pollutants has necessitated the search for efficient removal methods.Phytoremediation is an eco-friendly technique that provides multiple benefits over conventional methods of removing contaminants.Despite the numerous benefits of this technique,it has certain limitations that can be addressed by incorporating nanoparticles to improve its effectiveness.This review paper aims to explore the impact of heavy metal pollution on plants and human health.It highlights the role and mechanism of nanoparticles in enhancing phytoremediation,their application in the detection of heavy metals,and the strategies for the safe disposal of phytoremediation biomass.Biosynthesized nanoparticles are eco-friendly and non-toxic,with applications in biomedical and environmental fields.Nanoparticles can be used in the form of nano biosensors like smartphone-operated wireless sensors made from Cinnamomum camphora,enabling efficient detection of heavy metal ions.According to the studies,nanoparticles remove 80%–97%of heavy metals by various methods like reduction,precipitation,adsorption,etc.The phytoremediation biomass disposal can be done by heat treatment,phytomining,and microbial treatment with some modifications to further enhance their results.Phytoremediation is an environmentally friendly technique but requires further research and integration with biomass energy production to overcome scalability challenges and ensure safe biomass disposal.展开更多
The ectomycorrhizal fungus Paxillus involutus was inoculated onto tissue-cultures of the hybrid poplar,Populus davidiana×P.bolleana,to evaluate the elemental defense effect to heavy metals copper and cadmium at d...The ectomycorrhizal fungus Paxillus involutus was inoculated onto tissue-cultures of the hybrid poplar,Populus davidiana×P.bolleana,to evaluate the elemental defense effect to heavy metals copper and cadmium at different concentrations by simulating Alternaria alternata fungus infection.The enrichment capacity of Populus davidiana×P.bolleana for Cu and Cd was closely associated with the degree of heavy metal stress.There was a significant positive interaction of applying Cu and Cd and the inoculation with P.involutus on A.alternata leaf blight disease index.The incidence rate and disease index of leaf blight underwent a significant reduction compared with the controls.Similarly,the ratio of the area of disease spot to leaf area,incidence rate,and disease index for Populus davidiana×P.bolleana leaves inoculated with Paxillus involutus(Batsch)Fr.were significantly lower than those of their nonmycorrhizal counterparts.With increasing the degree of Cu and Cd stress,a gradual increase in the average value of the membership function for the incidence rate and disease index was observed,indicating the weakened pathogen's ability to cause infection and the improved resistance of Populus davidiana×P.bolleana to leaf blight disease under Cu and Cd stress.Moreover,superoxide dismutase enzyme activity in Populus davidiana×P.bolleana increased significantly,reaching levels of 411.0 U/g FW and 421.6 U/g FW under Cu and Cd treatments,respectively.These changes in metabolic products and antioxidant enzyme activities suggest that P.involutus may enhance the resistance of Populus davidiana×P.bolleana to the fungus,Alternaria alternata Fr.Keissel under heavy metal stress by modulating these physiological indicators.展开更多
In 2021,approximately 537 million people suffered from diabetes mellitus(DM)globally,and this figure will increase to approximately 783 million within the next quarter-century.The increasing burden of DM is a pressing...In 2021,approximately 537 million people suffered from diabetes mellitus(DM)globally,and this figure will increase to approximately 783 million within the next quarter-century.The increasing burden of DM is a pressing global public health issue.Therefore,the early identification of high-risk groups and implementation of effective intervention measures is imperative.展开更多
The recovery of precious metals(PMs)from secondary resources is critical for addressing global supply-chain vulnerabilities and sustainable resource utilization.This review systematically examines the transformative p...The recovery of precious metals(PMs)from secondary resources is critical for addressing global supply-chain vulnerabilities and sustainable resource utilization.This review systematically examines the transformative potential of metal-organic frameworks(MOFs)as next-generation adsorbents for PM recovery,focusing on their synthesis,functionalization,and multiscale adsorption mechanisms.We critically analyze conventional pyrometallurgical and hydrometallurgical methods and highlight their limitations in terms of selectivity,energy consumption,and secondary pollution.In contrast,MOFs offer tunable porosity,abundant active sites,and tunable surface chemistry,enabling efficient PM capture via synergistic physical and chemical adsorption.Advanced modification techniques,including direct synthesis and post-synthetic modification,are reviewed to propose strategies for enhancing the adsorption kinetics and selectivity for Au,Ag,Pt,and Pd.Key structure-property relationships are established through multiscale characterization and thermodynamic models,revealing the critical roles of hierarchical porosity,soft donor atoms,and framework stability.Industrial challenges,such as aqueous stability and scalability,are addressed via Zr-O bond strengthening,hydrophobic functionalization,and support immobilization.This study consolidates the experimental and theoretical advances in MOF-based PM recovery and provides a roadmap for translating laboratory innovations into practical applications within the circular-economy framework.展开更多
Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler ...Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler metals is ever-increasing.It is of great significance to investigate the optimized composition design methods and to establish systematic design guidelines for brazing filler metals.This study elucidated the fundamental rules for the composition design of brazing filler metals from a three-dimensional perspective encompassing the basic properties of applied brazing filler metals,formability and processability,and overall cost.The basic properties of brazing filler metals refer to their mechanical properties,physicochemical properties,electromagnetic properties,corrosion resistance,and the wettability and fluidity during brazing.The formability and processability of brazing filler metals include the processes of smelting and casting,extrusion,rolling,drawing and ring-making,as well as the processes of granulation,powder production,and the molding of amorphous and microcrystalline structures.The cost of brazing filler metals corresponds to the sum of materials value and manufacturing cost.Improving the comprehensive properties of brazing filler metals requires a comprehensive and systematic consideration of design indicators.Highlighting the unique characteristics of brazing filler metals should focus on relevant technical indicators.Binary or ternary eutectic structures can effectively enhance the flow spreading ability of brazing filler metals,and solid solution structures contribute to the formability.By employing the proposed design guidelines,typical Ag based,Cu based,Zn based brazing filler metals,and Sn based solders were designed and successfully applied in major scientific and engineering projects.展开更多
Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents ca...Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents can effectively alleviate both benign and malignant biliary strictures,but the plastic and metal stents that are currently used cannot degrade and nearly has no beneficial biological effects,therefore their long-term service can result into inflammation,the formation of sludges and re-obstruction of bile duct.In recent years,magnesium(Mg)metal has been received increasing attention in the field of biomedical application due to its excellent biocompatibility,adequate mechanical properties,biodegradability and other advantages,such as anti-inflammatory and anti-tumor properties.The research on biliary stents made of magnesium metals(BSMM)has also made significant progress and a series of experiments in vitro and vivo has proved their possibility.However,there are still some problems holding back BSMM’s clinical use,including rapid corrosion rate and potential harmful reaction.In this review,we would summarize the current research of BSMM,evaluate their clinical benefits,find the choke points,and discuss the solving method.展开更多
Dissolved copper and iron ions are regarded as friendly and economic catalysts for peroxymonosulfate(PMS)activation,however,neither Cu(Ⅱ)nor Fe(Ⅲ)shows efficient catalytic performance because of the slow rates of Cu...Dissolved copper and iron ions are regarded as friendly and economic catalysts for peroxymonosulfate(PMS)activation,however,neither Cu(Ⅱ)nor Fe(Ⅲ)shows efficient catalytic performance because of the slow rates of Cu(Ⅱ)/Cu(Ⅰ)and Fe(Ⅲ)/Fe(Ⅱ)cycles.Innovatively,we observed a significant enhancement on the degradation of organic contaminants when Cu(Ⅱ)and Fe(Ⅲ)were coupled to activate PMS in borate(BA)buffer.The degradation efficiency of Rhodamine B(RhB,20μmol/L)reached up to 96.3%within 10 min,which was higher than the sum of individual Cu(Ⅱ)-and Fe(Ⅲ)-activated PMS process.Sulfate radical,hydroxyl radical and high-valent metal ions(i.e.,Cu(Ⅲ)and Fe(IV))were identified as the working reactive species for RhB removal in Cu(Ⅱ)/Fe(Ⅲ)/PMS/BA system,while the last played a predominated role.The presence of BA dramatically facilitated the reduction of Cu(Ⅱ)to Cu(Ⅰ)via chelating with Cu(Ⅱ)followed by Fe(Ⅲ)reduction by Cu(Ⅰ),resulting in enhanced PMS activation by Cu(Ⅰ)and Fe(Ⅱ)as well as accelerated generation of reactive species.Additionally,the strong buffering capacity of BA to stabilize the solution pH was satisfying for the pollutants degradation since a slightly alkaline environment favored the PMS activation by coupling Cu(Ⅱ)and Fe(Ⅲ).In a word,this work provides a brand-new insight into the outstanding PMS activation by homogeneous bimetals and an expanded application of iron-based advanced oxidation processes in alkaline conditions.展开更多
Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to induci...Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to inducing antibiotic-HMs combined pollution.Recently,frequent human activities have led to more prominent antibiotics-HMs combined contamination in agricultural soils,especially the production and spread of antibiotic resistance genes(ARGs),heavy metal resistance genes(MRGs),antibiotic resistant bacteria(ARB),and antibiotics-HMs complexes(AMCs),which seriously threaten soil ecology and human health.This review describes the main sources(Intrinsic and manmade sources),composite mechanisms(co-selective resistance,oxidative stress,and Joint toxicity mechanism),environmental fate and the potential risks(soil ecological and human health risks)of antibiotics and HMs in agricultural soils.Finally,the current effective source blocking,transmission control,and attenuation strategies are classified for discussion,such as the application of additives and barrier materials,as well as plant and animal remediation and bioremediation,etc.,pointing out that future research should focus on the whole chain process of“source-processterminal”,intending to provide a theoretical basis and decision-making reference for future research.展开更多
Abandoned mines,especially pyrite-rich ones,release acid mine drainage(AMD)with high acidity and excessive amounts of heavy metals,threatening regional ecosystems.Six samples of mine drainage,nine samples of surface w...Abandoned mines,especially pyrite-rich ones,release acid mine drainage(AMD)with high acidity and excessive amounts of heavy metals,threatening regional ecosystems.Six samples of mine drainage,nine samples of surface water,and twelve samples of sediment were analyzed in this case study of the Dashu pyrite mine in southwest China.A comprehensive analysis of the pollution levels,pollution sources,and potential hazards of eight metals(Ni,Cd,Cu,Zn,Fe,Al,Pb,and Mn)that exceeded regulatory standardswas conducted bymonitoring 24 conventional and characteristic indicators.Ultimately,this research evaluated the environmental hazards associated with abandonedmine water using the"pressure-response"model,thereby providing valuable insights for the effective protection of the environment in mining regions.The primary pollutants in mine water were determined to be SO_(4)^(2−),Fe,and Mn,with concentrations of 7700,1450,and 6.78mg/L,respectively.A clear"source-sink"dynamic was observed between themine water and the surrounding water system.surface water was primarily polluted by Ni and Mn,while water system sediments were primarily polluted by Cu and Hg.Ion ratio and Pearson correlation analyses indicated heavy metals in surface water and sediments originated from the same AMD source.The"pressureresponse"model was used to assess the environmental hazards of water from abandoned mines.Mines W1,W2,W5,and W6 were classified as high-risk,while W3 and W4 were medium-risk.This study offers a novel approach and valuable reference for identifying and classifying environmental risks in abandoned mines and targeting AMD treatment.展开更多
Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study...Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study explores how photo-oxidation affects ROS gen-eration from aromatic compounds(ACs,including catechol(CAT),phthalic acid(PA),and 4,4-oxydibenzoic acid(4,4-OBA))and their mixtures with transition metals(TMs,includ-ing Fe(II),Mn(II),and Cu(II))using Fourier-transform infrared(FTIR)and Ultraviolet-visible spectroscopy(UV-Vis).Results showed that photo-oxidation facilitated ROS generation from ACs.CAT-Fe(II)/Cu(II)showed synergistic effects,but 4,4-OBA-Fe(II)/Cu(II)showed antag-onistic effects.ACs-Mn(II)and PA-Fe(II)/Cu(II)exhibited synergistic effects first and then showed antagonistic effects.The different interactions were due to complexation between ACs and TMs.The photo-oxidized ACs-TMs significantly enhanced ROS generation com-pared with ACs-TMs.The study suggested the photo-oxidation mechanism involved that the transfer ofπ-electrons from the ground to an excited state in benzene rings and func-tional groups,leading to the breakage and formation of chemical bonds or easierπ-electron transfer from ACs to TMs.The former could generate ROS directly or produce polymers that promoted ROS generation,while the latter promoted ROS generation by transferringπ-electrons to dissolved oxygen quickly.Our study revealed that both interactions among components and photo-oxidation significantly influenced ROS generation.Future studies should integrate broader atmospheric factors and PM components to fully assess oxidative potential and health impacts.展开更多
Phosphorus(P)poses a global challenge to the environment and human health due to its natural association with heavy metals.Sustainable use of P is crucial to ensure food security for future generations.An analysis of ...Phosphorus(P)poses a global challenge to the environment and human health due to its natural association with heavy metals.Sustainable use of P is crucial to ensure food security for future generations.An analysis of the 150 phosphate fertilizers stored at the Institute for Crop and Soil Science in Germany has been conducted,supplemented by previously published data.The elements Cd,Bi,U,Cr,Zn,Tl,As,B,Sb,Ni,and Se are found in higher concentrations in sedimentary derived phosphates compared to igneous derived phosphates.Mineral fertilizers contain more than ten times the amount of U,Cd,B,and As compared to farmyard manure.Principal component analyses(PCA)indicate that U,Cd,Be,and Cr are primarily present in sedimentary derived phosphates and their concentrations are 2 to 10 times higher than those in igneous derived phosphates.Regarding heavy metal contamination,over 1000 potential combinations were identified;36% of these were significant but weak(>0.1).It is estimated that approximately 707 t of uranium enter farmland annually through the application of mineral phosphate fertilizers in European countries.This contribution addresses environmental issues related to the utilization of rock phosphate as well as alternative production methods for cleaner and safer phosphate fertilizers while presenting a roadmap with measures for mitigation.展开更多
Capacitive pressure sensors have a promising application in the field of wearable electronic devices due to their excellent electrical properties.Owing to the complexity of the environment,capacitive sensors are susce...Capacitive pressure sensors have a promising application in the field of wearable electronic devices due to their excellent electrical properties.Owing to the complexity of the environment,capacitive sensors are susceptible to electromagnetic interference and changes in the surrounding medium,resulting in unstable signal acquisition.Capacitive sensor with excellent immunity to interference while maintaining flexibility is an urgent challenge.This study proposes an all-fiber anti-jamming capacitive pressure sensor that integrates liquid metal(LM)into a fiber-based dielectric layer.The combination of the LM and the fiber not only improves the dielectric properties of the dielectric layer but also reduces the Young's modulus of the fiber.The sensor has high interference immunity in various noise environments.Its all-fiber structure ensures lightweight,great air permeability and stretchability,whichmakes it a promising application in wearable electronic devices fields.展开更多
Ga_(2)O_(3) is considered a potential anode material for next-generation lithium-ion batteries due to its high theoretical capacity and unique self-healing capability.To develop a novel preparation method and in-depth...Ga_(2)O_(3) is considered a potential anode material for next-generation lithium-ion batteries due to its high theoretical capacity and unique self-healing capability.To develop a novel preparation method and in-depth understanding of the electrochemical reaction mechanism of Ga_(2)O_(3),a brand-new liquid-liquid dealloying strategy was exploited to construct porous α-Ga_(2)O_(3) nanowire networks.Profiting from the well-designed porous structure,the material exhibits impressive cycling stability of a reversible capacity of 603.9 mA·h/g after 200 cycles at 1000 mA/g and a capacity retention of 125.2 mA·h/g after 100 cycles at 0.5C when assembling to Ga_(2)O_(3)//LiFePO_(4) full cells.The lithiation/delithiation reaction mechanism of the porous Ga_(2)O_(3) anodes is further revealed by ex-situ Raman,XRD,TEM measurements,and density functional theoretical(DFT)calculations,which establishes a correlation between the electrochemical performance and the phase transition fromα-Ga_(2)O_(3) to β-Ga_(2)O_(3) during cycling.展开更多
Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,...Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.展开更多
A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge te...A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge ternary alloy was established to analyze the phase formation mechanism of filler metals based on Miedema model,Tanaka model,and Toop equation.This research provided a basis for the composition optimization of filler metals and the analysis of metallurgical reaction process between filler metals and base materials.Results show that Al-Si-Ge alloy is composed of Al-Ge eutectic phase,Al-Si eutectic phase,and primary Si.Ge addition promotes the precipitation of primary Si.Ge is the main melting point depressant element of filler metals.With the increase in Ge content from 10wt%to 40wt%,the solid phase line of filler metals remains unchanged,whereas the liquidus temperature decreases from 567.65°C to 499.96°C.With the increase in Ge content of filler metal,Ge content in eutectic Si phase is increased,the endothermic peak of Al-Si eutectic reaction according to thermogravimetry curve becomes smoother,and Al-Si eutectic temperature is decreased.Ge addition can reduce the free energy of Al-Si alloy system.The lowest point of free energy is located on Al-Ge side.The eutectic Ge phase with the composition similar to pure Ge composition is the most likely to appear in the microstructure of filler metals,whereas the eutectic Si phase with the composition similar to pure Si composition is the least likely to appear.The thermodynamic calculation results are consistent with the experiment results.展开更多
The failure of mechanical components is mainly caused by three key mechanisms:wear,corrosion,and fatigue.Among these failure modes,wear of mechanical components notably increases energy consumption and leads to substa...The failure of mechanical components is mainly caused by three key mechanisms:wear,corrosion,and fatigue.Among these failure modes,wear of mechanical components notably increases energy consumption and leads to substantial economic losses.Fe-Cr-C-B-Ti-Y wear-resistant cladding metals were prepared by the plasma cladding method.The wear performance of the cladding metals was analyzed using an MLS-23 rubber wheel wet sand wear tester.X-ray diffraction,scanning electron microscope,electron backscatter diffraction,and transmission electron microscope were employed to investigate the phase composition and microstructure of the cladding metals,followed by a discussion of their strengthening and wear mechanisms.The results indicate that the microstructure of Fe-Cr-C-B-Ti-Y cladding metals is composed of austeniteγ-Fe,M_(23)(C,B)_(6)eutectic carbide,and TiC hard phase.As the Y_(2)O_(3)content increases,the hardness and wear resistance of the cladding metal show a trend of first increasing and then decreasing.When the Y_(2)O_(3)content is 0.4wt%,the precipitation of TiC hard phase and M_(23)(C,B)_(6)-type eutectic carbides reaches maximum,and the grain size is the finest.The cladding metal exhibits optimal formability,featuring the smallest wetting angle of 52.2°.Under this condition,the Rockwell hardness value of the cladding metal is 89.7 HRC,and the wear mass loss is 0.27 g.The dominant wear mechanism of cladding metals is abrasive wear,and the material removal process involves micro-cutting and plowing.展开更多
Exploration budgets for primary battery metals-nickel,lithium and cobalt-tempered in 2024 at$1.697 billion,reflecting a marginal 0.4%decline and a virtually flat annual total,compared to$1.704 billion in 2023.Below is...Exploration budgets for primary battery metals-nickel,lithium and cobalt-tempered in 2024 at$1.697 billion,reflecting a marginal 0.4%decline and a virtually flat annual total,compared to$1.704 billion in 2023.Below is an introduction to the 2024 global exploration trends and prospects for lithium,cobalt,and nickel battery metals.展开更多
Fish constitutes the main protein source for the Amazonian population.However,the impact of different anthropogenic activities on trace element and metal accumulation in fish and their risks for human health at a regi...Fish constitutes the main protein source for the Amazonian population.However,the impact of different anthropogenic activities on trace element and metal accumulation in fish and their risks for human health at a regional scale remain largely unexplored.Here we assessed exposure levels of 10 trace elements andmetals(Cr,Mn,Fe,Ni,Cu,Zn,As,Cd,Pb,and Hg)in 56 samples belonging to 11 different species of fish from the Brazilian Amazon.We studied the relationship between exposure levels,fish origin,and fish feeding habits,and assessed toxicological and carcinogenic risks for the Amazonian population.No significant correlation was found between sampling site and exposure levels to the studied elements,but a significant difference was found between the accumulation of some metals and the position of the fish species in the food chain.The concentrations of Cr and Hg in fish flesh were found to exceed the Brazilian limits for human consumption.This study shows that current fish consumption patterns can lead to estimated daily intakes of Hg,As and Cr that exceed the oral reference dose,thus posing a toxicological concern.Furthermore,carcinogenic risks may be expected due to the continued exposure to Cr and As.The results of this study show that the consumption of wild caught fish in the Amazon region should be controlled.Moreover,continued monitoring of trace element and metal contamination in fish and on the health of the Amazonian population is recommended,particularly for riverine and indigenous communities.展开更多
基金National MCF Energy R&D Program(2024YFE03260300)。
文摘Refractory metals,including tungsten(W),tantalum(Ta),molybdenum(Mo),and niobium(Nb),play a vital role in industries,such as nuclear energy and aerospace,owing to their exceptional melting temperatures,thermal durability,and corrosion resistance.These metals have body-centered cubic crystal structure,characterized by limited slip systems and impeded dislocation motion,resulting in significant low-temperature brittleness,which poses challenges for the conventional processing.Additive manufacturing technique provides an innovative approach,enabling the production of intricate parts without molds,which significantly improves the efficiency of material usage.This review provides a comprehensive overview of the advancements in additive manufacturing techniques for the production of refractory metals,such as W,Ta,Mo,and Nb,particularly the laser powder bed fusion.In this review,the influence mechanisms of key process parameters(laser power,scan strategy,and powder characteristics)on the evolution of material microstructure,the formation of metallurgical defects,and mechanical properties were discussed.Generally,optimizing powder characteristics,such as sphericity,implementing substrate preheating,and formulating alloying strategies can significantly improve the densification and crack resistance of manufactured parts.Meanwhile,strictly controlling the oxygen impurity content and optimizing the energy density input are also the key factors to achieve the simultaneous improvement in strength and ductility of refractory metals.Although additive manufacturing technique provides an innovative solution for processing refractory metals,critical issues,such as residual stress control,microstructure and performance anisotropy,and process stability,still need to be addressed.This review not only provides a theoretical basis for the additive manufacturing of high-performance refractory metals,but also proposes forward-looking directions for their industrial application.
基金supported by grants from the National Natural Science Foundation of China(G.F.Wang,grant number 82204071)(P.Y.Su,grant numbers 81874268 and 82473655)the Research Funds of the Center for Big Data and Population Health of IHM(P.Y.Su,No.JKS2023016)Anhui Provincial Health Commission Scientific Research Project(Y.Zhou,No.AHWJ2023A30027)。
文摘Vitamin D deficiency(VDD)represents a significant nutritional concern among children and adolescents.The estimated prevalence of VDD in China is 46.8%in this population^([1]).VDD during childhood and adolescence has been associated with the onset of various conditions,including acute respiratory infections,asthma,atopic dermatitis,and food allergies^([2]).Multiple factors,including age,sun exposure,adiposity,and genetics,influence vitamin D levels^([2,3]).Increasing attention has been directed toward understanding the environmental determinants that may influence vitamin D status.Given the potential of metallic pollutants to disrupt endocrine function and their ubiquity in the environment,investigating the effects of metal exposure on human vitamin D status,particularly in vulnerable populations,is imperative.
文摘The surge in environmental pollution in recent years driven by numerous pollutants has necessitated the search for efficient removal methods.Phytoremediation is an eco-friendly technique that provides multiple benefits over conventional methods of removing contaminants.Despite the numerous benefits of this technique,it has certain limitations that can be addressed by incorporating nanoparticles to improve its effectiveness.This review paper aims to explore the impact of heavy metal pollution on plants and human health.It highlights the role and mechanism of nanoparticles in enhancing phytoremediation,their application in the detection of heavy metals,and the strategies for the safe disposal of phytoremediation biomass.Biosynthesized nanoparticles are eco-friendly and non-toxic,with applications in biomedical and environmental fields.Nanoparticles can be used in the form of nano biosensors like smartphone-operated wireless sensors made from Cinnamomum camphora,enabling efficient detection of heavy metal ions.According to the studies,nanoparticles remove 80%–97%of heavy metals by various methods like reduction,precipitation,adsorption,etc.The phytoremediation biomass disposal can be done by heat treatment,phytomining,and microbial treatment with some modifications to further enhance their results.Phytoremediation is an environmentally friendly technique but requires further research and integration with biomass energy production to overcome scalability challenges and ensure safe biomass disposal.
基金supported by the National Natural Science Foundation of China(31800542)Natural Science Foundation of Heilongjiang Province(LH2023C105)Heilongjiang Research Institutes Basic Research Funding Project(LKSB2024-9)。
文摘The ectomycorrhizal fungus Paxillus involutus was inoculated onto tissue-cultures of the hybrid poplar,Populus davidiana×P.bolleana,to evaluate the elemental defense effect to heavy metals copper and cadmium at different concentrations by simulating Alternaria alternata fungus infection.The enrichment capacity of Populus davidiana×P.bolleana for Cu and Cd was closely associated with the degree of heavy metal stress.There was a significant positive interaction of applying Cu and Cd and the inoculation with P.involutus on A.alternata leaf blight disease index.The incidence rate and disease index of leaf blight underwent a significant reduction compared with the controls.Similarly,the ratio of the area of disease spot to leaf area,incidence rate,and disease index for Populus davidiana×P.bolleana leaves inoculated with Paxillus involutus(Batsch)Fr.were significantly lower than those of their nonmycorrhizal counterparts.With increasing the degree of Cu and Cd stress,a gradual increase in the average value of the membership function for the incidence rate and disease index was observed,indicating the weakened pathogen's ability to cause infection and the improved resistance of Populus davidiana×P.bolleana to leaf blight disease under Cu and Cd stress.Moreover,superoxide dismutase enzyme activity in Populus davidiana×P.bolleana increased significantly,reaching levels of 411.0 U/g FW and 421.6 U/g FW under Cu and Cd treatments,respectively.These changes in metabolic products and antioxidant enzyme activities suggest that P.involutus may enhance the resistance of Populus davidiana×P.bolleana to the fungus,Alternaria alternata Fr.Keissel under heavy metal stress by modulating these physiological indicators.
基金supported by the Research Funds of the Center for Big Data and Population Health of IHM(grant number JKS2022015)the Key Scientific Research Fund of the Anhui Provincial Education Department(grant number2023AH050610)the Anhui Natural Science Foundation(grant number 1808085QH252)。
文摘In 2021,approximately 537 million people suffered from diabetes mellitus(DM)globally,and this figure will increase to approximately 783 million within the next quarter-century.The increasing burden of DM is a pressing global public health issue.Therefore,the early identification of high-risk groups and implementation of effective intervention measures is imperative.
基金supported by the National Natural Science Foundation of China(No.52304329)the Yunnan Fundamental Research Projects(No.202201BE070001-003),Guo Lin would like to acknowledge Xing Dian talent support program of Yunnan Province.
文摘The recovery of precious metals(PMs)from secondary resources is critical for addressing global supply-chain vulnerabilities and sustainable resource utilization.This review systematically examines the transformative potential of metal-organic frameworks(MOFs)as next-generation adsorbents for PM recovery,focusing on their synthesis,functionalization,and multiscale adsorption mechanisms.We critically analyze conventional pyrometallurgical and hydrometallurgical methods and highlight their limitations in terms of selectivity,energy consumption,and secondary pollution.In contrast,MOFs offer tunable porosity,abundant active sites,and tunable surface chemistry,enabling efficient PM capture via synergistic physical and chemical adsorption.Advanced modification techniques,including direct synthesis and post-synthetic modification,are reviewed to propose strategies for enhancing the adsorption kinetics and selectivity for Au,Ag,Pt,and Pd.Key structure-property relationships are established through multiscale characterization and thermodynamic models,revealing the critical roles of hierarchical porosity,soft donor atoms,and framework stability.Industrial challenges,such as aqueous stability and scalability,are addressed via Zr-O bond strengthening,hydrophobic functionalization,and support immobilization.This study consolidates the experimental and theoretical advances in MOF-based PM recovery and provides a roadmap for translating laboratory innovations into practical applications within the circular-economy framework.
基金National Natural Science Foundation of China(U22A20191)。
文摘Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler metals is ever-increasing.It is of great significance to investigate the optimized composition design methods and to establish systematic design guidelines for brazing filler metals.This study elucidated the fundamental rules for the composition design of brazing filler metals from a three-dimensional perspective encompassing the basic properties of applied brazing filler metals,formability and processability,and overall cost.The basic properties of brazing filler metals refer to their mechanical properties,physicochemical properties,electromagnetic properties,corrosion resistance,and the wettability and fluidity during brazing.The formability and processability of brazing filler metals include the processes of smelting and casting,extrusion,rolling,drawing and ring-making,as well as the processes of granulation,powder production,and the molding of amorphous and microcrystalline structures.The cost of brazing filler metals corresponds to the sum of materials value and manufacturing cost.Improving the comprehensive properties of brazing filler metals requires a comprehensive and systematic consideration of design indicators.Highlighting the unique characteristics of brazing filler metals should focus on relevant technical indicators.Binary or ternary eutectic structures can effectively enhance the flow spreading ability of brazing filler metals,and solid solution structures contribute to the formability.By employing the proposed design guidelines,typical Ag based,Cu based,Zn based brazing filler metals,and Sn based solders were designed and successfully applied in major scientific and engineering projects.
基金supported by Natural Science Foundation of Hunan Province(2021JJ31081,2024JJ5619)the Science Fund of State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle(No 32215004).
文摘Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents can effectively alleviate both benign and malignant biliary strictures,but the plastic and metal stents that are currently used cannot degrade and nearly has no beneficial biological effects,therefore their long-term service can result into inflammation,the formation of sludges and re-obstruction of bile duct.In recent years,magnesium(Mg)metal has been received increasing attention in the field of biomedical application due to its excellent biocompatibility,adequate mechanical properties,biodegradability and other advantages,such as anti-inflammatory and anti-tumor properties.The research on biliary stents made of magnesium metals(BSMM)has also made significant progress and a series of experiments in vitro and vivo has proved their possibility.However,there are still some problems holding back BSMM’s clinical use,including rapid corrosion rate and potential harmful reaction.In this review,we would summarize the current research of BSMM,evaluate their clinical benefits,find the choke points,and discuss the solving method.
基金supported by the Sichuan Science and Technology Program(No.2021YJ0385)the Project in Yangtze River Ecological Environment Protection and Restoration(No.2022-LHYJ-02-0509-08).
文摘Dissolved copper and iron ions are regarded as friendly and economic catalysts for peroxymonosulfate(PMS)activation,however,neither Cu(Ⅱ)nor Fe(Ⅲ)shows efficient catalytic performance because of the slow rates of Cu(Ⅱ)/Cu(Ⅰ)and Fe(Ⅲ)/Fe(Ⅱ)cycles.Innovatively,we observed a significant enhancement on the degradation of organic contaminants when Cu(Ⅱ)and Fe(Ⅲ)were coupled to activate PMS in borate(BA)buffer.The degradation efficiency of Rhodamine B(RhB,20μmol/L)reached up to 96.3%within 10 min,which was higher than the sum of individual Cu(Ⅱ)-and Fe(Ⅲ)-activated PMS process.Sulfate radical,hydroxyl radical and high-valent metal ions(i.e.,Cu(Ⅲ)and Fe(IV))were identified as the working reactive species for RhB removal in Cu(Ⅱ)/Fe(Ⅲ)/PMS/BA system,while the last played a predominated role.The presence of BA dramatically facilitated the reduction of Cu(Ⅱ)to Cu(Ⅰ)via chelating with Cu(Ⅱ)followed by Fe(Ⅲ)reduction by Cu(Ⅰ),resulting in enhanced PMS activation by Cu(Ⅰ)and Fe(Ⅱ)as well as accelerated generation of reactive species.Additionally,the strong buffering capacity of BA to stabilize the solution pH was satisfying for the pollutants degradation since a slightly alkaline environment favored the PMS activation by coupling Cu(Ⅱ)and Fe(Ⅲ).In a word,this work provides a brand-new insight into the outstanding PMS activation by homogeneous bimetals and an expanded application of iron-based advanced oxidation processes in alkaline conditions.
基金supported by the National Natural Science Foundation of China(No.32171615)the National Key R&D Program of China(2019YFC1804102)。
文摘Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to inducing antibiotic-HMs combined pollution.Recently,frequent human activities have led to more prominent antibiotics-HMs combined contamination in agricultural soils,especially the production and spread of antibiotic resistance genes(ARGs),heavy metal resistance genes(MRGs),antibiotic resistant bacteria(ARB),and antibiotics-HMs complexes(AMCs),which seriously threaten soil ecology and human health.This review describes the main sources(Intrinsic and manmade sources),composite mechanisms(co-selective resistance,oxidative stress,and Joint toxicity mechanism),environmental fate and the potential risks(soil ecological and human health risks)of antibiotics and HMs in agricultural soils.Finally,the current effective source blocking,transmission control,and attenuation strategies are classified for discussion,such as the application of additives and barrier materials,as well as plant and animal remediation and bioremediation,etc.,pointing out that future research should focus on the whole chain process of“source-processterminal”,intending to provide a theoretical basis and decision-making reference for future research.
基金supported by the National Key Research and Development Program of China(No.2023YFC3710000)the National Natural Science Foundation of China(Nos.42277078 and 42307118).
文摘Abandoned mines,especially pyrite-rich ones,release acid mine drainage(AMD)with high acidity and excessive amounts of heavy metals,threatening regional ecosystems.Six samples of mine drainage,nine samples of surface water,and twelve samples of sediment were analyzed in this case study of the Dashu pyrite mine in southwest China.A comprehensive analysis of the pollution levels,pollution sources,and potential hazards of eight metals(Ni,Cd,Cu,Zn,Fe,Al,Pb,and Mn)that exceeded regulatory standardswas conducted bymonitoring 24 conventional and characteristic indicators.Ultimately,this research evaluated the environmental hazards associated with abandonedmine water using the"pressure-response"model,thereby providing valuable insights for the effective protection of the environment in mining regions.The primary pollutants in mine water were determined to be SO_(4)^(2−),Fe,and Mn,with concentrations of 7700,1450,and 6.78mg/L,respectively.A clear"source-sink"dynamic was observed between themine water and the surrounding water system.surface water was primarily polluted by Ni and Mn,while water system sediments were primarily polluted by Cu and Hg.Ion ratio and Pearson correlation analyses indicated heavy metals in surface water and sediments originated from the same AMD source.The"pressureresponse"model was used to assess the environmental hazards of water from abandoned mines.Mines W1,W2,W5,and W6 were classified as high-risk,while W3 and W4 were medium-risk.This study offers a novel approach and valuable reference for identifying and classifying environmental risks in abandoned mines and targeting AMD treatment.
基金supported by the Weiqiao-UCAS Special Projects on Low-Carbon Technology Development(No.GYY-DTFZ-2022-007)the Fundamental Research Funds for the Central Universities(No.E0E48927×2)the National Natural Science Foundation of China(No.21677145).
文摘Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study explores how photo-oxidation affects ROS gen-eration from aromatic compounds(ACs,including catechol(CAT),phthalic acid(PA),and 4,4-oxydibenzoic acid(4,4-OBA))and their mixtures with transition metals(TMs,includ-ing Fe(II),Mn(II),and Cu(II))using Fourier-transform infrared(FTIR)and Ultraviolet-visible spectroscopy(UV-Vis).Results showed that photo-oxidation facilitated ROS generation from ACs.CAT-Fe(II)/Cu(II)showed synergistic effects,but 4,4-OBA-Fe(II)/Cu(II)showed antag-onistic effects.ACs-Mn(II)and PA-Fe(II)/Cu(II)exhibited synergistic effects first and then showed antagonistic effects.The different interactions were due to complexation between ACs and TMs.The photo-oxidized ACs-TMs significantly enhanced ROS generation com-pared with ACs-TMs.The study suggested the photo-oxidation mechanism involved that the transfer ofπ-electrons from the ground to an excited state in benzene rings and func-tional groups,leading to the breakage and formation of chemical bonds or easierπ-electron transfer from ACs to TMs.The former could generate ROS directly or produce polymers that promoted ROS generation,while the latter promoted ROS generation by transferringπ-electrons to dissolved oxygen quickly.Our study revealed that both interactions among components and photo-oxidation significantly influenced ROS generation.Future studies should integrate broader atmospheric factors and PM components to fully assess oxidative potential and health impacts.
基金funded by the Project of Yunnan Province’s Xingdian Talents Support Program(yfgrc202437)the Project of the International Cooperation Science Program of National Natural Science Foundation of China(42361144885).
文摘Phosphorus(P)poses a global challenge to the environment and human health due to its natural association with heavy metals.Sustainable use of P is crucial to ensure food security for future generations.An analysis of the 150 phosphate fertilizers stored at the Institute for Crop and Soil Science in Germany has been conducted,supplemented by previously published data.The elements Cd,Bi,U,Cr,Zn,Tl,As,B,Sb,Ni,and Se are found in higher concentrations in sedimentary derived phosphates compared to igneous derived phosphates.Mineral fertilizers contain more than ten times the amount of U,Cd,B,and As compared to farmyard manure.Principal component analyses(PCA)indicate that U,Cd,Be,and Cr are primarily present in sedimentary derived phosphates and their concentrations are 2 to 10 times higher than those in igneous derived phosphates.Regarding heavy metal contamination,over 1000 potential combinations were identified;36% of these were significant but weak(>0.1).It is estimated that approximately 707 t of uranium enter farmland annually through the application of mineral phosphate fertilizers in European countries.This contribution addresses environmental issues related to the utilization of rock phosphate as well as alternative production methods for cleaner and safer phosphate fertilizers while presenting a roadmap with measures for mitigation.
基金financially supported by the National Natural Science Foundation of China(Nos.U20A20166,52371202,52125205,52250398,52192614 and 52003101)the National Key R&D Program of China(No.2021YFB3200300)+2 种基金the Natural Science Foundation of Beijing Municipality(No.2222088)Shenzhen Science and Technology Program(No.KQTD20170810105439418)the Fundamental Research Funds for the Central Universities
文摘Capacitive pressure sensors have a promising application in the field of wearable electronic devices due to their excellent electrical properties.Owing to the complexity of the environment,capacitive sensors are susceptible to electromagnetic interference and changes in the surrounding medium,resulting in unstable signal acquisition.Capacitive sensor with excellent immunity to interference while maintaining flexibility is an urgent challenge.This study proposes an all-fiber anti-jamming capacitive pressure sensor that integrates liquid metal(LM)into a fiber-based dielectric layer.The combination of the LM and the fiber not only improves the dielectric properties of the dielectric layer but also reduces the Young's modulus of the fiber.The sensor has high interference immunity in various noise environments.Its all-fiber structure ensures lightweight,great air permeability and stretchability,whichmakes it a promising application in wearable electronic devices fields.
基金the Natural Science Foundation of Hebei Province,China(No.E2023202253)Hebei Higher Education Teaching Reform Research and Practice Project,China(No.2021GJJG050).
文摘Ga_(2)O_(3) is considered a potential anode material for next-generation lithium-ion batteries due to its high theoretical capacity and unique self-healing capability.To develop a novel preparation method and in-depth understanding of the electrochemical reaction mechanism of Ga_(2)O_(3),a brand-new liquid-liquid dealloying strategy was exploited to construct porous α-Ga_(2)O_(3) nanowire networks.Profiting from the well-designed porous structure,the material exhibits impressive cycling stability of a reversible capacity of 603.9 mA·h/g after 200 cycles at 1000 mA/g and a capacity retention of 125.2 mA·h/g after 100 cycles at 0.5C when assembling to Ga_(2)O_(3)//LiFePO_(4) full cells.The lithiation/delithiation reaction mechanism of the porous Ga_(2)O_(3) anodes is further revealed by ex-situ Raman,XRD,TEM measurements,and density functional theoretical(DFT)calculations,which establishes a correlation between the electrochemical performance and the phase transition fromα-Ga_(2)O_(3) to β-Ga_(2)O_(3) during cycling.
基金supported by the National Key Research and Development Program of China(No.2022YFB3505301)the National Key Research and Development Program of Shanxi Province(No.202302050201014)+2 种基金the National Natural Science Foundation of China(No.12304148)the Natural Science Basic Research Program of Shanxi Province(No.202203021222219)the China Postdoctoral Science Foundation(No.2023M731452).
文摘Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.
基金National Natural Science Foundation of China(U22A20191)。
文摘A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge ternary alloy was established to analyze the phase formation mechanism of filler metals based on Miedema model,Tanaka model,and Toop equation.This research provided a basis for the composition optimization of filler metals and the analysis of metallurgical reaction process between filler metals and base materials.Results show that Al-Si-Ge alloy is composed of Al-Ge eutectic phase,Al-Si eutectic phase,and primary Si.Ge addition promotes the precipitation of primary Si.Ge is the main melting point depressant element of filler metals.With the increase in Ge content from 10wt%to 40wt%,the solid phase line of filler metals remains unchanged,whereas the liquidus temperature decreases from 567.65°C to 499.96°C.With the increase in Ge content of filler metal,Ge content in eutectic Si phase is increased,the endothermic peak of Al-Si eutectic reaction according to thermogravimetry curve becomes smoother,and Al-Si eutectic temperature is decreased.Ge addition can reduce the free energy of Al-Si alloy system.The lowest point of free energy is located on Al-Ge side.The eutectic Ge phase with the composition similar to pure Ge composition is the most likely to appear in the microstructure of filler metals,whereas the eutectic Si phase with the composition similar to pure Si composition is the least likely to appear.The thermodynamic calculation results are consistent with the experiment results.
文摘The failure of mechanical components is mainly caused by three key mechanisms:wear,corrosion,and fatigue.Among these failure modes,wear of mechanical components notably increases energy consumption and leads to substantial economic losses.Fe-Cr-C-B-Ti-Y wear-resistant cladding metals were prepared by the plasma cladding method.The wear performance of the cladding metals was analyzed using an MLS-23 rubber wheel wet sand wear tester.X-ray diffraction,scanning electron microscope,electron backscatter diffraction,and transmission electron microscope were employed to investigate the phase composition and microstructure of the cladding metals,followed by a discussion of their strengthening and wear mechanisms.The results indicate that the microstructure of Fe-Cr-C-B-Ti-Y cladding metals is composed of austeniteγ-Fe,M_(23)(C,B)_(6)eutectic carbide,and TiC hard phase.As the Y_(2)O_(3)content increases,the hardness and wear resistance of the cladding metal show a trend of first increasing and then decreasing.When the Y_(2)O_(3)content is 0.4wt%,the precipitation of TiC hard phase and M_(23)(C,B)_(6)-type eutectic carbides reaches maximum,and the grain size is the finest.The cladding metal exhibits optimal formability,featuring the smallest wetting angle of 52.2°.Under this condition,the Rockwell hardness value of the cladding metal is 89.7 HRC,and the wear mass loss is 0.27 g.The dominant wear mechanism of cladding metals is abrasive wear,and the material removal process involves micro-cutting and plowing.
文摘Exploration budgets for primary battery metals-nickel,lithium and cobalt-tempered in 2024 at$1.697 billion,reflecting a marginal 0.4%decline and a virtually flat annual total,compared to$1.704 billion in 2023.Below is an introduction to the 2024 global exploration trends and prospects for lithium,cobalt,and nickel battery metals.
基金supported by the National Geographic Society through an early career grant to A.Rico (EC-59809C-19)Support Programme-PlanGenT (CIDEGENT/2020/043)of the Generalitat ValencianaR.Oliveira acknowledges"Fundacao de Amparo a Pesquisa do Estado de Sao Paulo"-FAPESP (Project 2018/03108-0).
文摘Fish constitutes the main protein source for the Amazonian population.However,the impact of different anthropogenic activities on trace element and metal accumulation in fish and their risks for human health at a regional scale remain largely unexplored.Here we assessed exposure levels of 10 trace elements andmetals(Cr,Mn,Fe,Ni,Cu,Zn,As,Cd,Pb,and Hg)in 56 samples belonging to 11 different species of fish from the Brazilian Amazon.We studied the relationship between exposure levels,fish origin,and fish feeding habits,and assessed toxicological and carcinogenic risks for the Amazonian population.No significant correlation was found between sampling site and exposure levels to the studied elements,but a significant difference was found between the accumulation of some metals and the position of the fish species in the food chain.The concentrations of Cr and Hg in fish flesh were found to exceed the Brazilian limits for human consumption.This study shows that current fish consumption patterns can lead to estimated daily intakes of Hg,As and Cr that exceed the oral reference dose,thus posing a toxicological concern.Furthermore,carcinogenic risks may be expected due to the continued exposure to Cr and As.The results of this study show that the consumption of wild caught fish in the Amazon region should be controlled.Moreover,continued monitoring of trace element and metal contamination in fish and on the health of the Amazonian population is recommended,particularly for riverine and indigenous communities.
