Although the Mg-air battery with high theoretical energy density is desirable for the energy supply of marine engineering equipment,its applications remain limited due to the low actual discharge voltage and inferior ...Although the Mg-air battery with high theoretical energy density is desirable for the energy supply of marine engineering equipment,its applications remain limited due to the low actual discharge voltage and inferior Mg anode utilization rate.In addition to the microstructure of Mg alloy anodes,the properties of discharge product films are of great importance to the discharge performance.Herein,the discharge behaviors of Mg-Y-Zn alloys are first studied mainly from the perspective of film properties.Through contrastive analysis,it is found that the sufficient Y^(3+) produced during the discharge process can substitute Mg^(2+) in Mg(OH)_(2) to introduce effective cation vacancies.The Mg-Y-Zn anode with profuse cation vacancies in the product film shows a synergy of potential and efficiency,and this can be attributed to an increase in the migration pathway for Mg^(2+),reducing the diffusion over-potential caused by the protective product film.This study is expected to provide a new strategy from the perspective of cation vacancy design of discharge film for developing high-performance Mg-air batteries.展开更多
The study of the shear behavior of bonded rock-cement interface is important for understanding the strength and stability of grouted rock masses.This research aims to reveal the failure mechanism behind the shear prop...The study of the shear behavior of bonded rock-cement interface is important for understanding the strength and stability of grouted rock masses.This research aims to reveal the failure mechanism behind the shear property of bonded rock-cement interfaces.For the study,sandstone and granite joint blocks with specific morphology were fabricated by using a three-dimensional(3D)engraving technique.Bonded rock-cement joints with asperity inclination angles of 15°,30°,and 45°were prepared.Shear tests were performed on these bonded rock-cement joints to investigate the shear response and failure modes considering the effect of applied normal stress and interface morphology.Meanwhile,the two-dimensional particle flow code(PFC2D)was utilized to model the entire shear process of bonded rock-cement interfaces.The macroscopic shear behavior and mesoscopic failure mechanism were comprehensively investigated by the laboratory test and numerical simulation.The results showed that the shear stress-displacement curves of bonded rock-cement joints exhibit two distinct peaks,and the shear stress evolution can be categorized into four stages including elastic growth,rapid stress drop,secondary stress growth,and progressive softening.Significantly,the number of acoustic emission events also exhibits two distinct peaks related to the double peak of the shear stress curves.The failure of bonded rock-cement interfaces is mainly induced by shear fractures,while the failure of rock and cement blocks is primarily caused by tensile fractures.The number of shear cracks in the bonded rock-cement interfaces reaches the peak when the shear stress reaches the primary peak;whereas as the shear stress continuously approaches the residual stage,the fracture of the bonded rock-cement joints is primarily characterized by tensile cracks in the blocks.展开更多
The tradeoff between strength and corrosion resistance restricts the development of low-alloyed magnesium(Mg)alloys.In this work,a low-alloyed Mg-1Sm-0.8Mn-0.5Ca-0.4Zn alloy was prepared through a simple process of co...The tradeoff between strength and corrosion resistance restricts the development of low-alloyed magnesium(Mg)alloys.In this work,a low-alloyed Mg-1Sm-0.8Mn-0.5Ca-0.4Zn alloy was prepared through a simple process of conventional casting followed by proper hotextrusion.The as-extruded alloy exhibits a very high yield strength of 402 MPa,an acceptable elongation of 5%,and a low corrosion rate of 0.56 mm y^(-1) which is close to that of high-purity Mg,and such comprehensive properties are superior to most reported Mg alloys,whether high alloying or low alloying.The special fine microstructure is responsible for high strength,including fine dynamic recrystallized(DRXed)grains,strong textured un-DRXed grains,dislocations and uniformly dispersed nano-spaced α-Mn nano-precipitates.An important finding of this study is that the corrosion film microstructure has amorphous characteristics,and this inevitably contributes to the high film protectiveness,and finally improves the corrosion resistance of the as-extruded alloy with relatively strong micro-galvanic corrosion tendency.In addition,the influence of micro/submicron-sized Mg_(2)Ca with anodic nature and nano-sized cathode α-Mn precipitates with strong strengthening effect on the corrosion film is also discussed.This study suggests that the strength-corrosion tradeoff can be evaded by regulating the microstructure of alloy substrate and corrosion film in the low-alloyed Mg alloy.展开更多
The complexity and intricacy of the brain,which is composed of billions of neurons,pose significant challenges to its study.Understanding neural connections and communication at the single-cell level is crucial for un...The complexity and intricacy of the brain,which is composed of billions of neurons,pose significant challenges to its study.Understanding neural connections and communication at the single-cell level is crucial for unraveling the brain’s functions.This study presents a novel strategy that utilizes magnetic nanoparticles(MNPs)and magnetic fields to manipulate neurons,thereby creating customized small-scale neural circuits for studying neural connections.To establish the feasibility of this approach,the effects of MNPs on neurons were initially investigated,demonstrating their low toxicity.Subsequently,a micromagnet array(MMA)chip was employed to manipulate the neurons,facilitating their precise arrangement on the electrodes.Over several days,the neurons extended their axons and established connections with neighboring cells,forming small-scale circular neural circuits.These artificially engineered circuits offer a simplified and controlled environment for studying neural networks in contrast to naturally occurring biological networks.Furthermore,electrophysiological recordings were conducted to investigate the connections between the manipulated neurons.This study introduces a customized small-scale neural circuit platform with electrode-specific recording and stimulating capabilities,enabling the study of neuron-to-neuron interactions at the single-cell level.By leveraging MNPs and an MMA chip,this research offers a powerful tool for studying neural connections and advancing our understanding of the brain’s intricate workings.展开更多
In this work,the synthesis of uniform zeolitic imidazolate framework-coated Mo-glycerate spheres and their subsequent conversion into hierarchical architecture containing bimetallic selenides heterostructures and nitr...In this work,the synthesis of uniform zeolitic imidazolate framework-coated Mo-glycerate spheres and their subsequent conversion into hierarchical architecture containing bimetallic selenides heterostructures and nitrogen-doped carbon shell are reported.Selenization temperature plays a significant role in determining the phases,morphology,and lithium-ion storage performance of the composite.Notably,the optimal electrode demonstrates an ultrahigh reversible capacity of 1298.2 mAh/g after 100 cycles at 0.2 A/g and an outstanding rate capability with the capacity still maintained 505.7 mAh/g after 300 cycles at 1.0 A/g,surpassing the calculated theoretical capacity according to individual component and most of the reported MoSe@C-or ZnSe@C-based anodes.Furthermore,ex-situ X-ray diffraction patterns reveal the combined conversion and alloying reaction mechanisms of the composite.展开更多
Magnesium and its alloys have garnered significant attention as promising materials for bone tissue engineering,owing to their bone-like density and elastic modulus,favorable mechanical properties,biodegradability,bio...Magnesium and its alloys have garnered significant attention as promising materials for bone tissue engineering,owing to their bone-like density and elastic modulus,favorable mechanical properties,biodegradability,biocompatibility,and diverse biological activities.However,rapid degradation,subcutaneous gas formation from H_(2)release,and osteolysis caused by elevated Mg concentrations have limited its widespread clinical application.In this study,Mg-3.0Gd-1Zn-0.4Zr(GZ31K)alloy with desirable uniform degradation and stress corrosion resistance under extruded and drawn condition was used as internal fixation implants for fracture healing,while the commercially available WE43 alloy was used as control.Results revealed that GZ31K alloy exhibited refined grain structure,nanoscale distributed stacking faults and superior corrosion resistance compared to WE43 alloy.The corrosion rate of the extruded GZ31K and WE43 alloys are 0.25 mm/year and 0.35 mm/year,meeting the corrosion tolerance threshold for orthopedic implants(<0.5 mm/year).In vitro study demonstrated that GZ31K alloy exhibited pronounced biocompatibilities and osteogenic bioactivities towards rat bone marrow mesenchymal stem cells(rBMSCs)compared with WE43 alloy,as evidenced by the enhanced ALP activity level,mineralized nodule formation and expression of osteogenicrelated marker genes.In vivo results confirmed that GZ31K alloy retained its above 87.1%structural integrity for up to 8 weeks postimplantation and exhibited better corrosion resistance compared to the WE43 alloy(80.9%).Besides,the Sprague-Dawley rats administrated with GZ31K alloy exhibited greater bone volume,trabecular thickness,satisfactory load-bearing performance and surface degradation behavior at 8 weeks post-fracture healing compared to the Kirschner wire and the WE43 alloy.Taken together,these findings highlighted that GZ31K alloy with slower degradation rate,enhanced structural stability,exceptional biocompatibilities and osteogenic potential might provide sustained structural integrity and mechanical support throughout the fracture healing process,positioning it as a strong candidate for next-generation orthopedic implants.展开更多
Implants are inevitably subjected to stress corrosion,bringing serious challenges to the controlled degradation of biomedical Mg alloys.It is worth studying the stress corrosion cracking(SCC)behavior of Mg alloy and e...Implants are inevitably subjected to stress corrosion,bringing serious challenges to the controlled degradation of biomedical Mg alloys.It is worth studying the stress corrosion cracking(SCC)behavior of Mg alloy and exploring Mg alloy with good SCC resistance for wide biomedical applications.In this work,the as-cast and as-extruded Mg-3Gd-1Zn-0.4Zr(GZ31K)alloys with uniform corrosion were used to investigate SCC behavior.The as-extruded GZ31K alloy exhibited better corrosion resistance and mechanical properties than the as-cast one mainly owing to grain refinement and uniformly distributed fine precipitates,and possessed superior SCC resistance.To clarify the SCC mechanism,the slow strain rate tests were assisted with applied constant potentials via an electrochemical workstation.Accelerated anodic dissolution at anodic polarization deteriorated SCC resistance due to the initiation of corrosion pits and micro-cracks.However,cathodic polarization had no obvious effects on SCC resistance,along with both retarded corrosion and accelerated hydrogen evolution.Stacking faults in GZ31K alloy were hydrogen capture containers to reduce the effect of hydrogen on SCC resistance during cathodic polarization.These findings provide new insights into the evaluation of SCC mechanism,and offer more opportunities to explore Mg alloys with good SCC resistance by regulating anodic dissolution.展开更多
To solve the problem of the lack of reference material(RM)for determination of allergenic ingredients in food,a RM of cashew nut powder was developed in the study.Cashew nut powder was prepared from cashew nut kernel ...To solve the problem of the lack of reference material(RM)for determination of allergenic ingredients in food,a RM of cashew nut powder was developed in the study.Cashew nut powder was prepared from cashew nut kernel by selecting,cleaning,crushing,n-hexane degreasing and sieving treatment.The reliability and traceability of RM was verified using real-time quantitative polymerase chain reaction(qPCR)and phylogenetic tree analysis.The cashew nut powder RM showed good homogeneity,and good stability under long-term storage at 4℃and short-term simulated transportation from-20 to 45℃.The RM was determined jointly by 8 collaborative laboratories,and the characteristic CT value was 24.732,and the extended uncertainty was 1.052%(k=2).The RM was applied to verify the amplification efficiency and the limit of detection for qPCR assay,and showed good applicability.The RM could be used for method validation and quality control,for the determination of allergenic ingredients in food mixed with trace amounts of cashew nut.展开更多
The article Magnetic nanoparticles for single-neuron manipulation to design a customized neural circuit,written by Hongyong Zhang,Lingrui Zhao,Nan Huang,Xiaobo Zhang,Tian Xu,Sumin Bian,and Mohamad Sawan,was originally...The article Magnetic nanoparticles for single-neuron manipulation to design a customized neural circuit,written by Hongyong Zhang,Lingrui Zhao,Nan Huang,Xiaobo Zhang,Tian Xu,Sumin Bian,and Mohamad Sawan,was originally published electronically on the publisher’s internet portal on 22 May 2025 without open access.展开更多
Geothermal resources in China are distributed throughout the country, with hydrother- real systems of high temperature in the Tibet Autonomous Region, Yunnan Province and Taiwan Island and hydrothermal systems of low-...Geothermal resources in China are distributed throughout the country, with hydrother- real systems of high temperature in the Tibet Autonomous Region, Yunnan Province and Taiwan Island and hydrothermal systems of low-medium temperature mainly in various sedimentary basins. Devel- opment and exploration of geothermal energy in China are below expectations. The purpose of this study is to comparatively review the characteristics （geology, hydrogeology, hydrochemistry and geo- physical data） of typical hydrothermal fields/areas and suggest development and utilization approaches in the future. Hydrothermal systems formed by mountain Hfting contain a considerable amount of en- ergy for geothermal power generation, especially in the Tibet Autonomous Region, Yunnan Province and Taiwan Island. However, geothermal water in the Tatun geothermal field has high TDS （total dis- solved solids）, an issue that requires more research to resolve this problem for power generation. The large storage of geothermal resources has been investigated in Meso-Cenozoic sedimentary basins; it is basically used for heating, bathing or greenhouse plantation. Moreover, hydrothermal resources of low-medium temperature can also be used in binary power plants. Although the enhanced geothermal systems （EGS） in China are promising, the resources have not yet been commercially exploited, because the emerging technologies （hydraulic fracturing） and concerns over environmental impacts （induced miero-seismicity） lead to slow development. On the contrary, shallow geothermal energy has been di- rectly utilized mainly for heating and cooling buildings. Cities like Beijing, Tianjin and Shenyang have established a series of ground-source heat-pump systems, which has led to a massive reduction of CO2 emission of 19.87×10^6 t.展开更多
Magnesium(Mg)alloys have been widely used in automobile,aviation,computer,and other fields due to their lightweight,high specific strength and stiffness,low pollution,and good electromagnetic shielding performance.How...Magnesium(Mg)alloys have been widely used in automobile,aviation,computer,and other fields due to their lightweight,high specific strength and stiffness,low pollution,and good electromagnetic shielding performance.However,the chemical stability of Mg alloys is poor,especially in the corrosive medium environment with high stress corrosion sensitivity,which causes sudden damage to structural components and restricts their application field.In recent years,owing to the increasing failure rate of engineering structures caused by stress corrosion of Mg alloys,it has become necessary to understand and pay more attention to the stress corrosion cracking(SCC)behavior of Mg alloys.In this paper,the SCC mechanisms and test methods of Mg alloys have been summarized.The recent research progress on SCC of Mg alloys has been reviewed from the aspects of alloying,preparation process,surface modification,corrosive medium,and strain rate.More importantly,future research trends in the field of SCC of Mg alloys have also been proposed.展开更多
Corrosion is one of the most drawbacks which restricts the wide applications of Mg alloys.In the last decade,the corrosion behaviors of Mg alloys with stacking fault(SF)and/or long period stacking ordered(LPSO)structu...Corrosion is one of the most drawbacks which restricts the wide applications of Mg alloys.In the last decade,the corrosion behaviors of Mg alloys with stacking fault(SF)and/or long period stacking ordered(LPSO)structures have obtained increasing attention.However,the corrosion mechanism of the SF–or LPSO–containing Mg alloys has not been well illustrated and even reverse results have been reported.In this paper,we have reviewed recent reports on corrosion behaviors of SF–or LPSO–containing Mg alloys to better clarify and understand the significance and mechanism.Moreover,some deficiencies are presented and advises are proposed for the development of corrosion resistant Mg alloys with SF or LPSO structures.展开更多
It is a long-term challenge to further improve the corrosion resistance while ensuring the strength of magnesium(Mg)alloys.Revealing the effect of potential fluctuation on the micro-galvanic corrosion and the subseque...It is a long-term challenge to further improve the corrosion resistance while ensuring the strength of magnesium(Mg)alloys.Revealing the effect of potential fluctuation on the micro-galvanic corrosion and the subsequent film formation is important for understanding the corrosion mechanism of Mg alloys with multiple strengthening phases/structures.Here,we prepared the high-strength Mg-14.4Er-1.44Zn-0.3Zr(wt.%)alloys containing hybrid structures,i.e.,elongated long-period stacking ordered(LPSO)blocks+intragranular stacking faults(SFs)/LPSO lamellae.The Mg alloy with elongated LPSO blocks and intragranular LPSO lamellae(EZ-500 alloy)obtains good corrosion resistance(2.2 mm y^(–1)),while the Mg alloy containing elongated LPSO blocks and intragranular SFs(EZ-400 alloy)shows a significantly higher corrosion rate(6.9 mm y^(–1)).The results of scanning Kelvin probe force microscopy(SKPFM)show the elongated LPSO blocks act as cathode phase(87 mV in EZ-400 alloy),and the SFs serve as the weak anode(30 mV in EZ-400 alloy),resulting in high potential fluctuation in EZ-400 alloy.On the contrary,both elongated blocks and intragranular lamellae are cathodic LPSO phase(67–69 mV)in EZ-500 alloy,leading to a lower potential fluctuation.Quasi in-situ atomic force microscope(AFM)observation indicates that high potential fluctuation would cause strong micro-galvanic corrosion,and subsequently leads to the failure in rapid formation of corrosion film,finally forming a loose and porous film,while relatively low potential fluctuation could result in more uniform corrosion mode and facilitate the rapid formation of protective film.Therefore,we propose that it is an effective way to develop high-strength corrosionresistant Mg alloys by controlling the potential fluctuation to form a“uniform potential”strengthening microstructure。展开更多
Simultaneously improving the mechanical properties and corrosion resistance of magnesium(Mg)alloys is a long-standing challenge to be solved in their engineering applications.In this work,we find that trace Er additio...Simultaneously improving the mechanical properties and corrosion resistance of magnesium(Mg)alloys is a long-standing challenge to be solved in their engineering applications.In this work,we find that trace Er addition can improve the mechanical and anti-corrosion properties of Mg-1.4Al-0.4Mn-0.4Ca-0.3Er(wt%,AMXE)dilute alloy synergistically,especially reducing the corrosion rate(0.75 mm y-1)by one order of magnitude compared with the reference Mg-1.4Al-0.4Mn-0.4Ca(AMX)alloy and making it comparable to that of high-purity Mg.Adding trace Er reduces the dynamic recrystallization degree and increases the strengthening phase particles,which is mainly responsible for the increase of yield strength by 42 MPa.The addition of Er promotes the formation of much less noble Al8Mn4Er with effective Fe trapping ability and induces dislocation segregation,thus dramatically reducing micro-galvanic corrosion tendency.Meanwhile,Er addition promotes the formation of a more passivation and dense corrosion film.These two factors together lead to the extremely low corrosion rate of AMXE alloy.Our findings are expected to promote the development of low alloyed high performance Mg alloys.展开更多
In order to study the effects of Nd addition on microstructure and mechanical properties of Mg-Gd-Zn-Zr alloys,the microstruc-ture and mechanical properties of the as-cast Mg-12Gd-2Zn-xNd-0.4Zr(x=0,0.5wt%,and 1wt%)all...In order to study the effects of Nd addition on microstructure and mechanical properties of Mg-Gd-Zn-Zr alloys,the microstruc-ture and mechanical properties of the as-cast Mg-12Gd-2Zn-xNd-0.4Zr(x=0,0.5wt%,and 1wt%)alloys were investigated by using optical microscope,scanning electron microscope,X-ray diffractometer,nano indentation tester,microhardness tester,and tensile testing machine.The results show that the microstructures mainly consist ofα-Mg matrix,eutectic phase,and stacking faults.The addition of Nd plays a significant role in grain refinement and uniform microstructure.The tensile yield strength and microhardness increase but the compression yield strength decreases with increasing Nd addition,leading to weakening tension-compression yield asymmetry in reverse of the Mg-12Gd-2Zn-xNd-0.4Zr alloys.The highest ultimate tensile strength(194 MPa)and ultimate compression strength(397 MPa)are obtained with 1wt%Nd addition of the alloy.展开更多
The Efficient Global Optimization(EGO)algorithm has been widely used in the numerical design optimization of engineering systems.However,the need for an uncertainty estimator limits the selection of a surrogate model....The Efficient Global Optimization(EGO)algorithm has been widely used in the numerical design optimization of engineering systems.However,the need for an uncertainty estimator limits the selection of a surrogate model.In this paper,a Sequential Ensemble Optimization(SEO)algorithm based on the ensemble model is proposed.In the proposed algorithm,there is no limitation on the selection of an individual surrogate model.Specifically,the SEO is built based on the EGO by extending the EGO algorithm so that it can be used in combination with the ensemble model.Also,a new uncertainty estimator for any surrogate model named the General Uncertainty Estimator(GUE)is proposed.The performance of the proposed SEO algorithm is verified by the simulations using ten well-known mathematical functions with varying dimensions.The results show that the proposed SEO algorithm performs better than the traditional EGO algorithm in terms of both the final optimization results and the convergence rate.Further,the proposed algorithm is applied to the global optimization control for turbo-fan engine acceleration schedule design.展开更多
To develop biodegradable magnesium alloy with desirable corrosion properties,a low Gd-containing Mg-3Gd-1Zn-0.4Zr(wt%,GZ31K)alloy was prepared.The as-cast ingot was solution treated and then hot extruded.Microstructur...To develop biodegradable magnesium alloy with desirable corrosion properties,a low Gd-containing Mg-3Gd-1Zn-0.4Zr(wt%,GZ31K)alloy was prepared.The as-cast ingot was solution treated and then hot extruded.Microstructures were characterized by scanning electron microscopy(SEM).Corrosion behavior of the alloy under each condition was studied by hydrogen evolution and quasi in-situ corrosion methods.It has been found that the as-cast alloy is composed ofα-Mg,stacking faults(SFs)at the outer edge of the matrix grains,and eutectic phase along the grain boundaries.After solution treatment,the SFs disappear and precipitates rich in Zn and Zr elements form in the grain interior and boundaries.The microstructure is significantly refined after extrusion.Hydrogen evolution tests show that the as-cast alloy exhibits the best corrosion resistance,and the solution-treated alloy has the worst corrosion resistance.Corrosion rate of the alloy under each condition decreases first and then increases with prolonging immersion time.Corrosion experiments demonstrate thatα-Mg was corroded preferentially,the eutectic phase and precipitates exhibit better corrosion resistance.The as-extruded alloy demonstrates uniform corrosion due to fine and homogeneous microstructure.展开更多
基金support of the Natural Science Foundation of Heilongjiang Province of China(No.LH2023E059)the National Natural Science Foundation of China(No.52071093)the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology(No.ASMA202205).
文摘Although the Mg-air battery with high theoretical energy density is desirable for the energy supply of marine engineering equipment,its applications remain limited due to the low actual discharge voltage and inferior Mg anode utilization rate.In addition to the microstructure of Mg alloy anodes,the properties of discharge product films are of great importance to the discharge performance.Herein,the discharge behaviors of Mg-Y-Zn alloys are first studied mainly from the perspective of film properties.Through contrastive analysis,it is found that the sufficient Y^(3+) produced during the discharge process can substitute Mg^(2+) in Mg(OH)_(2) to introduce effective cation vacancies.The Mg-Y-Zn anode with profuse cation vacancies in the product film shows a synergy of potential and efficiency,and this can be attributed to an increase in the migration pathway for Mg^(2+),reducing the diffusion over-potential caused by the protective product film.This study is expected to provide a new strategy from the perspective of cation vacancy design of discharge film for developing high-performance Mg-air batteries.
基金supported by the National Natural Science Foundation of China(Grant Nos.52369019,52004127)the Young Elite Scientists Sponsorship Program by JXAST(Grant No.2023QT06).
文摘The study of the shear behavior of bonded rock-cement interface is important for understanding the strength and stability of grouted rock masses.This research aims to reveal the failure mechanism behind the shear property of bonded rock-cement interfaces.For the study,sandstone and granite joint blocks with specific morphology were fabricated by using a three-dimensional(3D)engraving technique.Bonded rock-cement joints with asperity inclination angles of 15°,30°,and 45°were prepared.Shear tests were performed on these bonded rock-cement joints to investigate the shear response and failure modes considering the effect of applied normal stress and interface morphology.Meanwhile,the two-dimensional particle flow code(PFC2D)was utilized to model the entire shear process of bonded rock-cement interfaces.The macroscopic shear behavior and mesoscopic failure mechanism were comprehensively investigated by the laboratory test and numerical simulation.The results showed that the shear stress-displacement curves of bonded rock-cement joints exhibit two distinct peaks,and the shear stress evolution can be categorized into four stages including elastic growth,rapid stress drop,secondary stress growth,and progressive softening.Significantly,the number of acoustic emission events also exhibits two distinct peaks related to the double peak of the shear stress curves.The failure of bonded rock-cement interfaces is mainly induced by shear fractures,while the failure of rock and cement blocks is primarily caused by tensile fractures.The number of shear cracks in the bonded rock-cement interfaces reaches the peak when the shear stress reaches the primary peak;whereas as the shear stress continuously approaches the residual stage,the fracture of the bonded rock-cement joints is primarily characterized by tensile cracks in the blocks.
基金the support of the National Natural Science Foundation of China(52471126,52071093)the Natural Science Foundation of Heilongjiang Province of China(LH2023E059)the Scientific and Technological Developing Scheme of Jilin Province(SKL202302038).
文摘The tradeoff between strength and corrosion resistance restricts the development of low-alloyed magnesium(Mg)alloys.In this work,a low-alloyed Mg-1Sm-0.8Mn-0.5Ca-0.4Zn alloy was prepared through a simple process of conventional casting followed by proper hotextrusion.The as-extruded alloy exhibits a very high yield strength of 402 MPa,an acceptable elongation of 5%,and a low corrosion rate of 0.56 mm y^(-1) which is close to that of high-purity Mg,and such comprehensive properties are superior to most reported Mg alloys,whether high alloying or low alloying.The special fine microstructure is responsible for high strength,including fine dynamic recrystallized(DRXed)grains,strong textured un-DRXed grains,dislocations and uniformly dispersed nano-spaced α-Mn nano-precipitates.An important finding of this study is that the corrosion film microstructure has amorphous characteristics,and this inevitably contributes to the high film protectiveness,and finally improves the corrosion resistance of the as-extruded alloy with relatively strong micro-galvanic corrosion tendency.In addition,the influence of micro/submicron-sized Mg_(2)Ca with anodic nature and nano-sized cathode α-Mn precipitates with strong strengthening effect on the corrosion film is also discussed.This study suggests that the strength-corrosion tradeoff can be evaded by regulating the microstructure of alloy substrate and corrosion film in the low-alloyed Mg alloy.
基金supported by Westlake Universitythe Research Center for Industries of the Future of Westlake University (No. WU2022C040).
文摘The complexity and intricacy of the brain,which is composed of billions of neurons,pose significant challenges to its study.Understanding neural connections and communication at the single-cell level is crucial for unraveling the brain’s functions.This study presents a novel strategy that utilizes magnetic nanoparticles(MNPs)and magnetic fields to manipulate neurons,thereby creating customized small-scale neural circuits for studying neural connections.To establish the feasibility of this approach,the effects of MNPs on neurons were initially investigated,demonstrating their low toxicity.Subsequently,a micromagnet array(MMA)chip was employed to manipulate the neurons,facilitating their precise arrangement on the electrodes.Over several days,the neurons extended their axons and established connections with neighboring cells,forming small-scale circular neural circuits.These artificially engineered circuits offer a simplified and controlled environment for studying neural networks in contrast to naturally occurring biological networks.Furthermore,electrophysiological recordings were conducted to investigate the connections between the manipulated neurons.This study introduces a customized small-scale neural circuit platform with electrode-specific recording and stimulating capabilities,enabling the study of neuron-to-neuron interactions at the single-cell level.By leveraging MNPs and an MMA chip,this research offers a powerful tool for studying neural connections and advancing our understanding of the brain’s intricate workings.
基金supported by the National Natural Science Foundation of China(No.22265017)the Open Fund of Key Laboratory of Eco-functional Polymer Materials of the Ministry of Education(No.KF-21-04).
文摘In this work,the synthesis of uniform zeolitic imidazolate framework-coated Mo-glycerate spheres and their subsequent conversion into hierarchical architecture containing bimetallic selenides heterostructures and nitrogen-doped carbon shell are reported.Selenization temperature plays a significant role in determining the phases,morphology,and lithium-ion storage performance of the composite.Notably,the optimal electrode demonstrates an ultrahigh reversible capacity of 1298.2 mAh/g after 100 cycles at 0.2 A/g and an outstanding rate capability with the capacity still maintained 505.7 mAh/g after 300 cycles at 1.0 A/g,surpassing the calculated theoretical capacity according to individual component and most of the reported MoSe@C-or ZnSe@C-based anodes.Furthermore,ex-situ X-ray diffraction patterns reveal the combined conversion and alloying reaction mechanisms of the composite.
基金supported by Nanjing Health Bureau Medical Science and Technology Development Foundation(grant number:YKK21106)the National Natural Science Foundation of China(52071175)the Key Research&Development Plan(Social Development)of Jiangsu Province(BE2020702).
文摘Magnesium and its alloys have garnered significant attention as promising materials for bone tissue engineering,owing to their bone-like density and elastic modulus,favorable mechanical properties,biodegradability,biocompatibility,and diverse biological activities.However,rapid degradation,subcutaneous gas formation from H_(2)release,and osteolysis caused by elevated Mg concentrations have limited its widespread clinical application.In this study,Mg-3.0Gd-1Zn-0.4Zr(GZ31K)alloy with desirable uniform degradation and stress corrosion resistance under extruded and drawn condition was used as internal fixation implants for fracture healing,while the commercially available WE43 alloy was used as control.Results revealed that GZ31K alloy exhibited refined grain structure,nanoscale distributed stacking faults and superior corrosion resistance compared to WE43 alloy.The corrosion rate of the extruded GZ31K and WE43 alloys are 0.25 mm/year and 0.35 mm/year,meeting the corrosion tolerance threshold for orthopedic implants(<0.5 mm/year).In vitro study demonstrated that GZ31K alloy exhibited pronounced biocompatibilities and osteogenic bioactivities towards rat bone marrow mesenchymal stem cells(rBMSCs)compared with WE43 alloy,as evidenced by the enhanced ALP activity level,mineralized nodule formation and expression of osteogenicrelated marker genes.In vivo results confirmed that GZ31K alloy retained its above 87.1%structural integrity for up to 8 weeks postimplantation and exhibited better corrosion resistance compared to the WE43 alloy(80.9%).Besides,the Sprague-Dawley rats administrated with GZ31K alloy exhibited greater bone volume,trabecular thickness,satisfactory load-bearing performance and surface degradation behavior at 8 weeks post-fracture healing compared to the Kirschner wire and the WE43 alloy.Taken together,these findings highlighted that GZ31K alloy with slower degradation rate,enhanced structural stability,exceptional biocompatibilities and osteogenic potential might provide sustained structural integrity and mechanical support throughout the fracture healing process,positioning it as a strong candidate for next-generation orthopedic implants.
基金supported by the National Natural Science Foundation of China(52071175,52301304)the Natural Science Foundation of Jiangsu Province(BK20230704)+3 种基金the China Postdoctoral Science Foundation Funded Project(2023M731742)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(23KJB430019)the Research Fund of Nanjing Institute of Technology(YKJ202402)the Open Research Fund of Jiangsu Key Laboratory for Light Metal Alloys(LMA202401).
文摘Implants are inevitably subjected to stress corrosion,bringing serious challenges to the controlled degradation of biomedical Mg alloys.It is worth studying the stress corrosion cracking(SCC)behavior of Mg alloy and exploring Mg alloy with good SCC resistance for wide biomedical applications.In this work,the as-cast and as-extruded Mg-3Gd-1Zn-0.4Zr(GZ31K)alloys with uniform corrosion were used to investigate SCC behavior.The as-extruded GZ31K alloy exhibited better corrosion resistance and mechanical properties than the as-cast one mainly owing to grain refinement and uniformly distributed fine precipitates,and possessed superior SCC resistance.To clarify the SCC mechanism,the slow strain rate tests were assisted with applied constant potentials via an electrochemical workstation.Accelerated anodic dissolution at anodic polarization deteriorated SCC resistance due to the initiation of corrosion pits and micro-cracks.However,cathodic polarization had no obvious effects on SCC resistance,along with both retarded corrosion and accelerated hydrogen evolution.Stacking faults in GZ31K alloy were hydrogen capture containers to reduce the effect of hydrogen on SCC resistance during cathodic polarization.These findings provide new insights into the evaluation of SCC mechanism,and offer more opportunities to explore Mg alloys with good SCC resistance by regulating anodic dissolution.
基金supported by the National Key Research and Development Pro-gram of China(2021YFF0601902)the National Reference Material Development Project(S2022234).
文摘To solve the problem of the lack of reference material(RM)for determination of allergenic ingredients in food,a RM of cashew nut powder was developed in the study.Cashew nut powder was prepared from cashew nut kernel by selecting,cleaning,crushing,n-hexane degreasing and sieving treatment.The reliability and traceability of RM was verified using real-time quantitative polymerase chain reaction(qPCR)and phylogenetic tree analysis.The cashew nut powder RM showed good homogeneity,and good stability under long-term storage at 4℃and short-term simulated transportation from-20 to 45℃.The RM was determined jointly by 8 collaborative laboratories,and the characteristic CT value was 24.732,and the extended uncertainty was 1.052%(k=2).The RM was applied to verify the amplification efficiency and the limit of detection for qPCR assay,and showed good applicability.The RM could be used for method validation and quality control,for the determination of allergenic ingredients in food mixed with trace amounts of cashew nut.
文摘The article Magnetic nanoparticles for single-neuron manipulation to design a customized neural circuit,written by Hongyong Zhang,Lingrui Zhao,Nan Huang,Xiaobo Zhang,Tian Xu,Sumin Bian,and Mohamad Sawan,was originally published electronically on the publisher’s internet portal on 22 May 2025 without open access.
基金the financial support from the National Natural Science Foundation of China (No. 41672251)
文摘Geothermal resources in China are distributed throughout the country, with hydrother- real systems of high temperature in the Tibet Autonomous Region, Yunnan Province and Taiwan Island and hydrothermal systems of low-medium temperature mainly in various sedimentary basins. Devel- opment and exploration of geothermal energy in China are below expectations. The purpose of this study is to comparatively review the characteristics （geology, hydrogeology, hydrochemistry and geo- physical data） of typical hydrothermal fields/areas and suggest development and utilization approaches in the future. Hydrothermal systems formed by mountain Hfting contain a considerable amount of en- ergy for geothermal power generation, especially in the Tibet Autonomous Region, Yunnan Province and Taiwan Island. However, geothermal water in the Tatun geothermal field has high TDS （total dis- solved solids）, an issue that requires more research to resolve this problem for power generation. The large storage of geothermal resources has been investigated in Meso-Cenozoic sedimentary basins; it is basically used for heating, bathing or greenhouse plantation. Moreover, hydrothermal resources of low-medium temperature can also be used in binary power plants. Although the enhanced geothermal systems （EGS） in China are promising, the resources have not yet been commercially exploited, because the emerging technologies （hydraulic fracturing） and concerns over environmental impacts （induced miero-seismicity） lead to slow development. On the contrary, shallow geothermal energy has been di- rectly utilized mainly for heating and cooling buildings. Cities like Beijing, Tianjin and Shenyang have established a series of ground-source heat-pump systems, which has led to a massive reduction of CO2 emission of 19.87×10^6 t.
基金supported by the National Natural Science Foundation of China(52071175)the Key Research&Development Plan(Social Development)of Jiangsu Province(BE2020702)。
文摘Magnesium(Mg)alloys have been widely used in automobile,aviation,computer,and other fields due to their lightweight,high specific strength and stiffness,low pollution,and good electromagnetic shielding performance.However,the chemical stability of Mg alloys is poor,especially in the corrosive medium environment with high stress corrosion sensitivity,which causes sudden damage to structural components and restricts their application field.In recent years,owing to the increasing failure rate of engineering structures caused by stress corrosion of Mg alloys,it has become necessary to understand and pay more attention to the stress corrosion cracking(SCC)behavior of Mg alloys.In this paper,the SCC mechanisms and test methods of Mg alloys have been summarized.The recent research progress on SCC of Mg alloys has been reviewed from the aspects of alloying,preparation process,surface modification,corrosive medium,and strain rate.More importantly,future research trends in the field of SCC of Mg alloys have also been proposed.
基金supported by the Natural Science Foundation of Jiangsu Province for Outstanding Youth(BK20160081)the Natural Science Foundation of Jiangsu Province(BK20181020)+2 种基金the Natural Science Foundation of Higher Education Institutions of Jiangsu Province–Key Project(18KJA430008)the“333 Project”of Jiangsu Province(BRA2018338)the Practical Innovative Project for Postgraduates of Jiangsu Province(SJCX19_0493).
文摘Corrosion is one of the most drawbacks which restricts the wide applications of Mg alloys.In the last decade,the corrosion behaviors of Mg alloys with stacking fault(SF)and/or long period stacking ordered(LPSO)structures have obtained increasing attention.However,the corrosion mechanism of the SF–or LPSO–containing Mg alloys has not been well illustrated and even reverse results have been reported.In this paper,we have reviewed recent reports on corrosion behaviors of SF–or LPSO–containing Mg alloys to better clarify and understand the significance and mechanism.Moreover,some deficiencies are presented and advises are proposed for the development of corrosion resistant Mg alloys with SF or LPSO structures.
基金supported by the National Natural Science Foundation of China(Nos.51871069,52071093,and 52201137)the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology(No.ASMA202205)+1 种基金the Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities(No.3072022GIP1004)the Beijing Municipal Natural Science Foundation(No.2202004).
文摘It is a long-term challenge to further improve the corrosion resistance while ensuring the strength of magnesium(Mg)alloys.Revealing the effect of potential fluctuation on the micro-galvanic corrosion and the subsequent film formation is important for understanding the corrosion mechanism of Mg alloys with multiple strengthening phases/structures.Here,we prepared the high-strength Mg-14.4Er-1.44Zn-0.3Zr(wt.%)alloys containing hybrid structures,i.e.,elongated long-period stacking ordered(LPSO)blocks+intragranular stacking faults(SFs)/LPSO lamellae.The Mg alloy with elongated LPSO blocks and intragranular LPSO lamellae(EZ-500 alloy)obtains good corrosion resistance(2.2 mm y^(–1)),while the Mg alloy containing elongated LPSO blocks and intragranular SFs(EZ-400 alloy)shows a significantly higher corrosion rate(6.9 mm y^(–1)).The results of scanning Kelvin probe force microscopy(SKPFM)show the elongated LPSO blocks act as cathode phase(87 mV in EZ-400 alloy),and the SFs serve as the weak anode(30 mV in EZ-400 alloy),resulting in high potential fluctuation in EZ-400 alloy.On the contrary,both elongated blocks and intragranular lamellae are cathodic LPSO phase(67–69 mV)in EZ-500 alloy,leading to a lower potential fluctuation.Quasi in-situ atomic force microscope(AFM)observation indicates that high potential fluctuation would cause strong micro-galvanic corrosion,and subsequently leads to the failure in rapid formation of corrosion film,finally forming a loose and porous film,while relatively low potential fluctuation could result in more uniform corrosion mode and facilitate the rapid formation of protective film.Therefore,we propose that it is an effective way to develop high-strength corrosionresistant Mg alloys by controlling the potential fluctuation to form a“uniform potential”strengthening microstructure。
基金support of the National Natural Science Foundation of China (Nos.51871069 and 52071093)the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology (No.ASMA202205).
文摘Simultaneously improving the mechanical properties and corrosion resistance of magnesium(Mg)alloys is a long-standing challenge to be solved in their engineering applications.In this work,we find that trace Er addition can improve the mechanical and anti-corrosion properties of Mg-1.4Al-0.4Mn-0.4Ca-0.3Er(wt%,AMXE)dilute alloy synergistically,especially reducing the corrosion rate(0.75 mm y-1)by one order of magnitude compared with the reference Mg-1.4Al-0.4Mn-0.4Ca(AMX)alloy and making it comparable to that of high-purity Mg.Adding trace Er reduces the dynamic recrystallization degree and increases the strengthening phase particles,which is mainly responsible for the increase of yield strength by 42 MPa.The addition of Er promotes the formation of much less noble Al8Mn4Er with effective Fe trapping ability and induces dislocation segregation,thus dramatically reducing micro-galvanic corrosion tendency.Meanwhile,Er addition promotes the formation of a more passivation and dense corrosion film.These two factors together lead to the extremely low corrosion rate of AMXE alloy.Our findings are expected to promote the development of low alloyed high performance Mg alloys.
基金financially supported by the National Natural Science Foundation of China(No.52071175)the Natural Science Foundation of Higher Education Institutions of Jiangsu Province-Key Project,China(No.18KJA430008)+1 种基金the Key Research&Development Plan(Social Development)of Jiangsu Province,China(No.BE2020702)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX21_0923).
文摘In order to study the effects of Nd addition on microstructure and mechanical properties of Mg-Gd-Zn-Zr alloys,the microstruc-ture and mechanical properties of the as-cast Mg-12Gd-2Zn-xNd-0.4Zr(x=0,0.5wt%,and 1wt%)alloys were investigated by using optical microscope,scanning electron microscope,X-ray diffractometer,nano indentation tester,microhardness tester,and tensile testing machine.The results show that the microstructures mainly consist ofα-Mg matrix,eutectic phase,and stacking faults.The addition of Nd plays a significant role in grain refinement and uniform microstructure.The tensile yield strength and microhardness increase but the compression yield strength decreases with increasing Nd addition,leading to weakening tension-compression yield asymmetry in reverse of the Mg-12Gd-2Zn-xNd-0.4Zr alloys.The highest ultimate tensile strength(194 MPa)and ultimate compression strength(397 MPa)are obtained with 1wt%Nd addition of the alloy.
基金the financial support of the National Natural Science Foundation of China(Nos.52076180,51876176 and 51906204)National Science and Technology Major Project,China(No.2017-I0001-0001)。
文摘The Efficient Global Optimization(EGO)algorithm has been widely used in the numerical design optimization of engineering systems.However,the need for an uncertainty estimator limits the selection of a surrogate model.In this paper,a Sequential Ensemble Optimization(SEO)algorithm based on the ensemble model is proposed.In the proposed algorithm,there is no limitation on the selection of an individual surrogate model.Specifically,the SEO is built based on the EGO by extending the EGO algorithm so that it can be used in combination with the ensemble model.Also,a new uncertainty estimator for any surrogate model named the General Uncertainty Estimator(GUE)is proposed.The performance of the proposed SEO algorithm is verified by the simulations using ten well-known mathematical functions with varying dimensions.The results show that the proposed SEO algorithm performs better than the traditional EGO algorithm in terms of both the final optimization results and the convergence rate.Further,the proposed algorithm is applied to the global optimization control for turbo-fan engine acceleration schedule design.
基金This project was supported by the Natural Science Foundation of Jiangsu Province for Outstanding Youth(BK20160081)the Natural Science Foundation of Higher Education Institutions of Jiangsu Province-Key Project(18KJA430008)+2 种基金the Jiangsu Government Scholarship for Overseas Studies,the“333 Project”of Jiangsu Province(BRA2018338)the National Natural Science Foundation of China(51701093)the Outstanding Scientific and Technological Innovation Team in Colleges and Universities of Jiangsu Province.
文摘To develop biodegradable magnesium alloy with desirable corrosion properties,a low Gd-containing Mg-3Gd-1Zn-0.4Zr(wt%,GZ31K)alloy was prepared.The as-cast ingot was solution treated and then hot extruded.Microstructures were characterized by scanning electron microscopy(SEM).Corrosion behavior of the alloy under each condition was studied by hydrogen evolution and quasi in-situ corrosion methods.It has been found that the as-cast alloy is composed ofα-Mg,stacking faults(SFs)at the outer edge of the matrix grains,and eutectic phase along the grain boundaries.After solution treatment,the SFs disappear and precipitates rich in Zn and Zr elements form in the grain interior and boundaries.The microstructure is significantly refined after extrusion.Hydrogen evolution tests show that the as-cast alloy exhibits the best corrosion resistance,and the solution-treated alloy has the worst corrosion resistance.Corrosion rate of the alloy under each condition decreases first and then increases with prolonging immersion time.Corrosion experiments demonstrate thatα-Mg was corroded preferentially,the eutectic phase and precipitates exhibit better corrosion resistance.The as-extruded alloy demonstrates uniform corrosion due to fine and homogeneous microstructure.
