In order to improve the osseointegration and antibacterial activity of titanium alloys,micro/nano-structured ceramic coatings doped with antibacterial element F were prepared by plasma electrolytic oxidation(PEO)proce...In order to improve the osseointegration and antibacterial activity of titanium alloys,micro/nano-structured ceramic coatings doped with antibacterial element F were prepared by plasma electrolytic oxidation(PEO)process on Ti6Al4V alloy in NaF electrolyte.The influence of NaF concentration(0.15-0.50 mol/L)on the PEO process,microstructure,phase composition,corrosion resistance and thickness of the coatings was investigated using scanning/transmission electron microscopy,energy dispersive spectroscopy,atomic force microscopy,X-ray diffractometer,and potentiodynamic polarization.The results demonstrated that Ti6Al4V alloy had low PEO voltage(less than 200 V)in NaF electrolyte,which decreased further as the NaF concentration increased.A micro/nano-structured coating with 10-15μm pits and 200-800 nm pores was formed in NaF electrolyte;the morphology was different from the typical pancake structure obtained with other electrolytes.The coating formed in NaF electrolyte had low surface roughness and was thin(<4μm).The NaF concentration had a small effect on the phase transition from metastable anatase phase to stable rutile phase,but greatly affected the corrosion resistance.In general,as the NaF concentration increased,the surface roughness,phase(anatase and rutile)contents,corrosion resistance,and thickness of the coating first increased and then decreased,reaching the maximum values at 0.25 mol/L NaF.展开更多
Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics.Given the global threat and increasing influence of...Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics.Given the global threat and increasing influence of antibiotic resistance,there is an urgent demand to explore novel antibacterial strategies other than using antibiotics.Recently,using a certain surface topography to provide a more persistent antibacterial solution attracts more and more attention.However,the clinical application of biomimetic nano-pillar array is not satisfactory,mainly because its antibacterial ability against Gram-positive strain is not good enough.Thus,the pillar array should be equipped with other antibacterial agents to fulfill the bacteriostatic and bactericidal requirements of clinical application.Here,we designed a novel model substrate which was a combination of periodic micro/nano-pillar array and TiO2 for basically understanding the topographical bacteriostatic effects of periodic micro/nano-pillar array and the photocatalytic bactericidal activity of TiO2.Such innovation may potentially exert the synergistic effects by integrating the persistent topographical antibacterial activity and the non-invasive X-ray induced photocatalytic antibacterial property of TiO2 to combat against antibiotic-resistant implant-associated infections.First,to separately verify the topographical antibacterial activity of TiO2 periodic micro/nano-pillar array,we systematically investigated its effects on bacterial adhesion,growth,proliferation,and viability in the dark without involving the photocatalysis of TiO2.The pillar array with sub-micron motif size can significantly inhibit the adhesion,growth,and proliferation of Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli).Such antibacterial ability is mainly attributed to a spatial confinement size-effect and limited contact area availability generated by the special topography of pillar array.Moreover,the pillar array is not lethal to S.aureus and E.coli in 24 h.Then,the X-ray induced photocatalytic antibacterial property of TiO2 periodic micro/nano-pillar array in vitro and in vivo will be systematically studied in a future work.This study could shed light on the direction of surface topography design for future medical implants to combat against antibiotic-resistant implant-associated infections without using antibiotics.展开更多
In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrol...In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrolytic Etching （EE）. MG-63 cells were cultured on disks for 2 h to 7 days. The osteoblast response to the hierarchical hybrid micro-/nano-structured titanium surface was evaluated through the osteoblast cell morphology, attachment and proliferation. For comparison, MG-63 cells were also cultured on Sandblasted and Acid-etched （SEA） as well as Machined （M） surfaces respectively. The results show signifi- cant differences in the adhesion rates and proliferation levels of MG-63 cells on EE, SLA, and M surfaces. Both adhesion rate and proliferation level on EE surface are higher than those on SLA and M surfaces. Therefore, we may expect that, comparing with SLA and M surfaces, bone growth on EE surface could be accelerated and bone formation could be promoted at an early stage, which could be applied in the clinical practices for immediate and early-stage loadings.展开更多
There exist strong interests of developing nano-grained steels because of the outstanding properties including high strength/weight ratio, wear resistance, excellent toughness, and favorable cellular activity. This ar...There exist strong interests of developing nano-grained steels because of the outstanding properties including high strength/weight ratio, wear resistance, excellent toughness, and favorable cellular activity. This article reviews the main fabrication process and microstructural control of nano-structured steels over the last decades. Severe plastic deformation is considered as an effective route of obtaining the nano-grained microstructures. The process of cold-rolling and annealing of martensitic steel is a viable method to obtain bulk nano-structured low carbon steel, while the final thickness of the cold-rolling plate is limited. According to the theoretical results of the thermal simulation studies, a novel alloy design combined with the rapid transformation and rolling process is proposed to successfully fabricate nano-grained high strength bulk steel. The refinement mechanisms are expected to be taking advantage of increase in the transformation nucleation sites and inhibiting the grain coarsening. Moreover, corresponding mechanical properties are summarized.展开更多
A novel oxide-dispersion-strengthened(ODS)die steel was fabricated by mechanical alloying and hot consolidation.Annealing and quench-tempering treatments both obtained an ultra-fine grain structure(mean size:310-330 n...A novel oxide-dispersion-strengthened(ODS)die steel was fabricated by mechanical alloying and hot consolidation.Annealing and quench-tempering treatments both obtained an ultra-fine grain structure(mean size:310-330 nm)with an ultra-high density of ultra-fine Y-Al-O nano-oxides(number density:~(1-1.5)×10^(23)m^(−3),mean size:5.1-7.2 nm).Prolonged thermal exposure further induced the new,highly dense precipitation of ultra-fine Y-Zr-O nano-oxides.Both nano-oxides tended to be wrapped up with a B2-NiAl nano-shells.Although the quench-tempered sample showed much higher room-temperature strength(yield strength=1393±40 MPa and ultimate tensile strength=1774±11 MPa)and slightly lower elongation(elongation=13.6%±0.6%)than the annealed sample(YS=988±7 MPa,UTS=1490±12 MPa,and EL=15.2%±1.1%),both samples exhibited better strength-ductility synergy at room temperature and much higher thermal stabilities at high temperatures(600-700℃)than all those conventional hot-work die steels,which makes the new ODS steel highly promising for advanced hot-work mold and die applications at high temperatures above 600℃.展开更多
First-principles energetics analyses were performed to investigate the nucleation of(Y-Si-O)nano-clusters(NCs)in nanostructured ferritic alloys(NFAs).It was predicted that the nucleation of(Y-Si-O)NCs follows the same...First-principles energetics analyses were performed to investigate the nucleation of(Y-Si-O)nano-clusters(NCs)in nanostructured ferritic alloys(NFAs).It was predicted that the nucleation of(Y-Si-O)NCs follows the same general pathway as previously found for(Y-Ti/Al/Zr-O)NCs in NFAs:they all tend to begin with the(O-O)pairs and grow to(O-Y)-cores and further to larger NCs by attracting Y and other solute elements nearby.Nucleation of a hexa-atomic-[2Y-Si-3O]-cluster can reduce the total energy by 4.71 eV.Among various microalloying-induced NCs,the nucleation preference ordering was predicted as(Y-Zr-O)>(Y-Ti-O)>(Y-Al-O)>(Y-Si-O).The number densities and chemical compositions of NCs in multi-microalloyed NFAs would largely depend on the number availability of(O,Y)-cores,as well as the relative abundance and atomic diffusivities of microalloying solute elements nearby.展开更多
Micro-arc oxidized Cu-incorporated TiO2 coatings （Cu-TiO2） were prepared in the Ca, P, Cu-containing electrolyte to obtain an implant material with superior biological activity and antibacterial property. The surfac...Micro-arc oxidized Cu-incorporated TiO2 coatings （Cu-TiO2） were prepared in the Ca, P, Cu-containing electrolyte to obtain an implant material with superior biological activity and antibacterial property. The surface topography, phase, and element composition of the TiO2 and Cu-TiO2 coatings were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and energy-dispersive X-ray spectrometry （EDS）, respectively. Staphylococcus aureus （S. aureus） was selected to evaluate the antibacterial property of the Cu-TiO2 coatings, whereas osteoblastic MG63 cells were cultured on the coatings to investigate the biological activity. The obtained results demonstrated that Cu element was successfully incorporated into the porous nano-structured TiO2 coatings, which did not alter apparently the surface topography and phase composition of the coatings as compared to the Cu-free TiO2 coatings. Moreover, the antibacterial studies suggested that the Cu-incorporated TiO2 coatings could significantly inhibit the adhesion of S. aureus. In addition, the in vitro biological evaluation displayed that the adhesion, proliferation and differentiation of MG63 cells on the Cu-incorporated coatings were enhanced as compared to those on the Cu-free coatings and Ti plates. In conclusion, the innovative Cu-incorporated nano-structured TiO2 coatings on Ti substrate with excellent antibacterial property and biological activity are promising candidates for orthopedic implant.展开更多
Micro/nanoplastics(M/NPs)have become pervasive environmental pollutants,posing significant risks to human health through various exposure routes,including ingestion,inhalation,and direct contact.This review systematic...Micro/nanoplastics(M/NPs)have become pervasive environmental pollutants,posing significant risks to human health through various exposure routes,including ingestion,inhalation,and direct contact.This review systematically examined the potential impacts of M/NPs on ocular health,focusing on exposure pathways,toxicological mechanisms,and resultant damage to the eye.Ocular exposure to M/NPs can occur via direct contact and oral ingestion,with the latter potentially leading to the penetration of particles through ocular biological barriers into ocular tissues.The review highlighted that M/NPs can induce adverse effects on the ocular surface,elevate intraocular pressure,and cause abnormalities in the vitreous and retina.Mechanistically,oxidative stress and inflammation are central to M/NP-induced ocular damage,with smaller particles often exhibiting greater toxicity.Overall,this review underscored the potential risks of M/NPs to ocular health and emphasized the need for further research to elucidate exposure mechanisms,toxicological pathways,and mitigation strategies.展开更多
Micro silicon(mSi)is a promising anode candidate for all-solid-state batteries due to its high specific capacity,low side reactions,and high tap density.However,silicon suffers from its poor electronic and ionic condu...Micro silicon(mSi)is a promising anode candidate for all-solid-state batteries due to its high specific capacity,low side reactions,and high tap density.However,silicon suffers from its poor electronic and ionic conductivity,which is particularly severe on a micro scale and in solid-state systems,leading to increased polarization and inferior electrochemical performance.Doping can broaden the transmission pathways and reduce the diffusion energy barrier for electrons and lithium ions.However,achieving effective,uniform doping in mSi is challenging due to its longer diffusion paths and higher energy barriers.Therefore,current doping research is primarily limited to nanosilicon.In this study,we successfully used a Joule-heating activated staged thermal treatment to achieve full-depth doping of germanium(Ge)in the mSi substrate.The Joule-heating process activated the mSi substrate,resulting in abundant vacancy defects that reduced the diffusion barrier of Ge into the silicon lattice and facilitated full-depth Ge doping.Surprisingly,the resulting Si-Ge anode exhibited significantly enhanced electrical conductivity(70 times).Meanwhile,the improved Li-ion conductivity in mSi and the reduced Young’s modulus enhance the electrode reaction kinetics and integrity after cycling.Ge-doped silicon anodes demonstrate excellent electrochemical performance when applied in sulfide solid-state half-cells and full-cells.This work provides substantial insights into the rational structural design of mSi alloyed anode materials,paving the way for the development of high-performance solid-state Li-ion batteries.展开更多
Extreme cold weather seriously harms human thermoregulatory system,necessitating high-performance insulating garments to maintain body temperature.However,as the core insulating layer,advanced fibrous materials always...Extreme cold weather seriously harms human thermoregulatory system,necessitating high-performance insulating garments to maintain body temperature.However,as the core insulating layer,advanced fibrous materials always struggle to balance mechanical properties and thermal insulation,resulting in their inability to meet the demands for both washing resistance and personal protection.Herein,inspired by the natural spring-like structures of cucumber tendrils,a superelastic and washable micro/nanofibrous sponge(MNFS)based on biomimetic helical fibers is directly prepared utilizing multiple-jet electrospinning technology for high-performance thermal insulation.By regulating the conductivity of polyvinylidene fluoride solution,multiple-jet ejection and multiple-stage whipping of jets are achieved,and further control of phase separation rates enables the rapid solidification of jets to form spring-like helical fibers,which are directly entangled to assemble MNFS.The resulting MNFS exhibits superelasticity that can withstand large tensile strain(200%),1000 cyclic tensile or compression deformations,and retain good resilience even in liquid nitrogen(-196℃).Furthermore,the MNFS shows efficient thermal insulation with low thermal conductivity(24.85 mW m^(-1)K^(-1)),close to the value of dry air,and remains structural stability even after cyclic washing.This work offers new possibilities for advanced fibrous sponges in transportation,environmental,and energy applications.展开更多
Strategically coupling nanoparticle hybrids and internal thermosensitive molecular switches establishes an innovative paradigm for constructing micro/nanoscale-reconfigurable robots,facilitating energyefficient CO_(2)...Strategically coupling nanoparticle hybrids and internal thermosensitive molecular switches establishes an innovative paradigm for constructing micro/nanoscale-reconfigurable robots,facilitating energyefficient CO_(2) management in life-support systems of confined space.Here,a micro/nano-reconfigurable robot is constructed from the CO_(2) molecular hunters,temperature-sensitive molecular switch,solar photothermal conversion,and magnetically-driven function engines.The molecular hunters within the molecular extension state can capture 6.19 mmol g^(−1) of CO_(2) to form carbamic acid and ammonium bicarbonate.Interestingly,the molecular switch of the robot activates a molecular curling state that facilitates CO_(2) release through nano-reconfiguration,which is mediated by the temperature-sensitive curling of Pluronic F127 molecular chains during the photothermal desorption.Nano-reconfiguration of robot alters the amino microenvironment,including increasing surface electrostatic potential of the amino group and decreasing overall lowest unoccupied molecular orbital energy level.This weakened the nucleophilic attack ability of the amino group toward the adsorption product derivatives,thereby inhibiting the side reactions that generate hard-to-decompose urea structures,achieving the lowest regeneration temperature of 55℃ reported to date.The engine of the robot possesses non-contact magnetically-driven micro-reconfiguration capability to achieve efficient photothermal regeneration while avoiding local overheating.Notably,the robot successfully prolonged the survival time of mice in the sealed container by up to 54.61%,effectively addressing the issue of carbon suffocation in confined spaces.This work significantly enhances life-support systems for deep-space exploration,while stimulating innovations in sustainable carbon management technologies for terrestrial extreme environments.展开更多
Mine filling materials urgently need to improve mechanical properties and achieve low-carbon transformation.This study explores the mechanism of the synergistic effect of optimizing aggregate fractal grading and intro...Mine filling materials urgently need to improve mechanical properties and achieve low-carbon transformation.This study explores the mechanism of the synergistic effect of optimizing aggregate fractal grading and introducing CO_(2)nanobubble technology to improve the performance of cement-fly ash-based backfill materials(CFB).The properties including fluidity,setting time,uniaxial compressive strength,elastic modulus,porosity,microstructure and CO_(2)storage performance were systematically studied through methods such as fluidity evaluation,time test,uniaxial compression test,mercury intrusion porosimetry(MIP),scanning electron microscopy-energy dispersive spectroscopy analysis(SEM-EDS),and thermogravimetric-differential thermogravimetric analysis(TG-DTG).The experimental results show that the density and strength of the material are significantly improved under the synergistic effect of fractal dimension and CO_(2)nanobubbles.When the fractal dimension reaches 2.65,the mass ratio of coarse and fine aggregates reaches the optimal balance,and the structural density is greatly improved at the same time.At this time,the uniaxial compressive strength and elastic modulus reach their peak values,with increases of up to 13.46%and 27.47%,respectively.CO_(2)nanobubbles enhance the material properties by promoting hydration reaction and carbonization.At the microscopic level,CO_(2)nanobubble water promotes the formation of C-S-H(hydrated calcium silicate),C-A-S-H(hydrated calcium aluminium silicate)gel and CaCO_(3),which is the main way to enhance the performance.Thermogravimetric studies have shown that when the fractal dimension is 2.65,the dehydration of hydration products and the decarbonization process of CaCO_(3)are most obvious,and CO_(2)nanobubble water promotes the carbonization reaction,making it surpass the natural state.The CO_(2)sequestration quality of cement-fly ash-based materials treated with CO_(2)nanobubble water at different fractal dimensions increased by 12.4wt%to 99.8wt%.The results not only provide scientific insights for the design and implementation of low-carbon filling materials,but also provide a solid theoretical basis for strengthening green mining practices and promoting sustainable resource utilization.展开更多
Modern power systems increasingly depend on interconnected microgrids to enhance reliability and renewable energy utilization.However,the high penetration of intermittent renewable sources often causes frequency devia...Modern power systems increasingly depend on interconnected microgrids to enhance reliability and renewable energy utilization.However,the high penetration of intermittent renewable sources often causes frequency deviations,voltage fluctuations,and poor reactive power coordination,posing serious challenges to grid stability.Conventional Interconnection FlowControllers(IFCs)primarily regulate active power flowand fail to effectively handle dynamic frequency variations or reactive power sharing in multi-microgrid networks.To overcome these limitations,this study proposes an enhanced Interconnection Flow Controller(e-IFC)that integrates frequency response balancing and an Interconnection Reactive Power Flow Controller(IRFC)within a unified adaptive control structure.The proposed e-IFC is implemented and analyzed in DIgSILENT PowerFactory to evaluate its performance under various grid disturbances,including frequency drops,load changes,and reactive power fluctuations.Simulation results reveal that the e-IFC achieves 27.4% higher active power sharing accuracy,19.6% lower reactive power deviation,and 18.2% improved frequency stability compared to the conventional IFC.The adaptive controller ensures seamless transitions between grid-connected and islanded modes and maintains stable operation even under communication delays and data noise.Overall,the proposed e-IFCsignificantly enhances active-reactive power coordination and dynamic stability in renewable-integrated multi-microgrid systems.Future research will focus on coupling the e-IFC with tertiary-level optimization frameworks and conducting hardware-in-the-loop validation to enable its application in large-scale smart microgrid environments.展开更多
Modulating the activation state and degree of macrophages still remains as a challenge for the topographical design of Ti-based implants.In this work,micro/nano-structured coatings were prepared on Ti substrates by mi...Modulating the activation state and degree of macrophages still remains as a challenge for the topographical design of Ti-based implants.In this work,micro/nano-structured coatings were prepared on Ti substrates by micro-arc oxidation(MAO)and subsequent hydrothermal(HT)treatment.By varying the HT conditions,plate-like nano-structures with an average length of 80,440 or 780 nm were obtained on MAO-prepared micro-topographical surfaces.Depending on the dimensional features of nano-plates,the specimens were noted as Micro,Micro/Nano-180,Micro/Nano-440 and Micro/Nano-780,respectively.The in vitro results showed that the activation state and degree of macrophages could be effectively modulated by the micro/nano-structured surfaces with various dimensional features.Compared to the Micro surface,the Micro/Nano-180 surface activated both M1 and M2 phenotype in macrophages,while the Micro/Nano-440 and Micro/Nano-780 surfaces polarized macrophages to their M1 phenotype.The activation degree of M1 macrophages followed the trend:Micro<Micro/Nano-180<Micro/Nano-440<Micro/Nano-780.However,the osteogenic potential of the activated macrophages in response to various surfaces were in the order:Micro≈Micro/Nano-780<Micro/Nano-180<Micro/Nano-440.Together,the findings presented in this work indicate that engineering nano-structures with controllable dimensional features is a promising strategy to modulate macrophage activation state and degree.In addition,it is essential to determine the appropriate activation degree of M1 macrophages for enhanced osteogenesis.展开更多
文摘In order to improve the osseointegration and antibacterial activity of titanium alloys,micro/nano-structured ceramic coatings doped with antibacterial element F were prepared by plasma electrolytic oxidation(PEO)process on Ti6Al4V alloy in NaF electrolyte.The influence of NaF concentration(0.15-0.50 mol/L)on the PEO process,microstructure,phase composition,corrosion resistance and thickness of the coatings was investigated using scanning/transmission electron microscopy,energy dispersive spectroscopy,atomic force microscopy,X-ray diffractometer,and potentiodynamic polarization.The results demonstrated that Ti6Al4V alloy had low PEO voltage(less than 200 V)in NaF electrolyte,which decreased further as the NaF concentration increased.A micro/nano-structured coating with 10-15μm pits and 200-800 nm pores was formed in NaF electrolyte;the morphology was different from the typical pancake structure obtained with other electrolytes.The coating formed in NaF electrolyte had low surface roughness and was thin(<4μm).The NaF concentration had a small effect on the phase transition from metastable anatase phase to stable rutile phase,but greatly affected the corrosion resistance.In general,as the NaF concentration increased,the surface roughness,phase(anatase and rutile)contents,corrosion resistance,and thickness of the coating first increased and then decreased,reaching the maximum values at 0.25 mol/L NaF.
基金supported by the Natural Science Foundation of Tianjin(General Program,No.18JCYBJC19500)the Independent Innovation Fund of Tianjin University(No.2019XZS-0014)the Research Grants Council of Hong Kong(No.HKUST615408).
文摘Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics.Given the global threat and increasing influence of antibiotic resistance,there is an urgent demand to explore novel antibacterial strategies other than using antibiotics.Recently,using a certain surface topography to provide a more persistent antibacterial solution attracts more and more attention.However,the clinical application of biomimetic nano-pillar array is not satisfactory,mainly because its antibacterial ability against Gram-positive strain is not good enough.Thus,the pillar array should be equipped with other antibacterial agents to fulfill the bacteriostatic and bactericidal requirements of clinical application.Here,we designed a novel model substrate which was a combination of periodic micro/nano-pillar array and TiO2 for basically understanding the topographical bacteriostatic effects of periodic micro/nano-pillar array and the photocatalytic bactericidal activity of TiO2.Such innovation may potentially exert the synergistic effects by integrating the persistent topographical antibacterial activity and the non-invasive X-ray induced photocatalytic antibacterial property of TiO2 to combat against antibiotic-resistant implant-associated infections.First,to separately verify the topographical antibacterial activity of TiO2 periodic micro/nano-pillar array,we systematically investigated its effects on bacterial adhesion,growth,proliferation,and viability in the dark without involving the photocatalysis of TiO2.The pillar array with sub-micron motif size can significantly inhibit the adhesion,growth,and proliferation of Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli).Such antibacterial ability is mainly attributed to a spatial confinement size-effect and limited contact area availability generated by the special topography of pillar array.Moreover,the pillar array is not lethal to S.aureus and E.coli in 24 h.Then,the X-ray induced photocatalytic antibacterial property of TiO2 periodic micro/nano-pillar array in vitro and in vivo will be systematically studied in a future work.This study could shed light on the direction of surface topography design for future medical implants to combat against antibiotic-resistant implant-associated infections without using antibiotics.
文摘In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrolytic Etching （EE）. MG-63 cells were cultured on disks for 2 h to 7 days. The osteoblast response to the hierarchical hybrid micro-/nano-structured titanium surface was evaluated through the osteoblast cell morphology, attachment and proliferation. For comparison, MG-63 cells were also cultured on Sandblasted and Acid-etched （SEA） as well as Machined （M） surfaces respectively. The results show signifi- cant differences in the adhesion rates and proliferation levels of MG-63 cells on EE, SLA, and M surfaces. Both adhesion rate and proliferation level on EE surface are higher than those on SLA and M surfaces. Therefore, we may expect that, comparing with SLA and M surfaces, bone growth on EE surface could be accelerated and bone formation could be promoted at an early stage, which could be applied in the clinical practices for immediate and early-stage loadings.
文摘There exist strong interests of developing nano-grained steels because of the outstanding properties including high strength/weight ratio, wear resistance, excellent toughness, and favorable cellular activity. This article reviews the main fabrication process and microstructural control of nano-structured steels over the last decades. Severe plastic deformation is considered as an effective route of obtaining the nano-grained microstructures. The process of cold-rolling and annealing of martensitic steel is a viable method to obtain bulk nano-structured low carbon steel, while the final thickness of the cold-rolling plate is limited. According to the theoretical results of the thermal simulation studies, a novel alloy design combined with the rapid transformation and rolling process is proposed to successfully fabricate nano-grained high strength bulk steel. The refinement mechanisms are expected to be taking advantage of increase in the transformation nucleation sites and inhibiting the grain coarsening. Moreover, corresponding mechanical properties are summarized.
基金support from the National MCF Energy R&D Program of China(No.2018YFE0306100).
文摘A novel oxide-dispersion-strengthened(ODS)die steel was fabricated by mechanical alloying and hot consolidation.Annealing and quench-tempering treatments both obtained an ultra-fine grain structure(mean size:310-330 nm)with an ultra-high density of ultra-fine Y-Al-O nano-oxides(number density:~(1-1.5)×10^(23)m^(−3),mean size:5.1-7.2 nm).Prolonged thermal exposure further induced the new,highly dense precipitation of ultra-fine Y-Zr-O nano-oxides.Both nano-oxides tended to be wrapped up with a B2-NiAl nano-shells.Although the quench-tempered sample showed much higher room-temperature strength(yield strength=1393±40 MPa and ultimate tensile strength=1774±11 MPa)and slightly lower elongation(elongation=13.6%±0.6%)than the annealed sample(YS=988±7 MPa,UTS=1490±12 MPa,and EL=15.2%±1.1%),both samples exhibited better strength-ductility synergy at room temperature and much higher thermal stabilities at high temperatures(600-700℃)than all those conventional hot-work die steels,which makes the new ODS steel highly promising for advanced hot-work mold and die applications at high temperatures above 600℃.
基金financially suppor ted by the National MCF Energy R&D Program of China(Project No.2018YFE0306100)the National Natural Science Foundation of China(No.51971249)。
文摘First-principles energetics analyses were performed to investigate the nucleation of(Y-Si-O)nano-clusters(NCs)in nanostructured ferritic alloys(NFAs).It was predicted that the nucleation of(Y-Si-O)NCs follows the same general pathway as previously found for(Y-Ti/Al/Zr-O)NCs in NFAs:they all tend to begin with the(O-O)pairs and grow to(O-Y)-cores and further to larger NCs by attracting Y and other solute elements nearby.Nucleation of a hexa-atomic-[2Y-Si-3O]-cluster can reduce the total energy by 4.71 eV.Among various microalloying-induced NCs,the nucleation preference ordering was predicted as(Y-Zr-O)>(Y-Ti-O)>(Y-Al-O)>(Y-Si-O).The number densities and chemical compositions of NCs in multi-microalloyed NFAs would largely depend on the number availability of(O,Y)-cores,as well as the relative abundance and atomic diffusivities of microalloying solute elements nearby.
基金supported by the Shanghai Science and Technology R&D Fund(Nos.0952nm04400,07JC14057 and 08ZR1421600)the National Basic Research Fund(No. 2005CB623901)the National Natural Science Foundation of China(Nos.30700170,30973041 and 81271959)
文摘Micro-arc oxidized Cu-incorporated TiO2 coatings （Cu-TiO2） were prepared in the Ca, P, Cu-containing electrolyte to obtain an implant material with superior biological activity and antibacterial property. The surface topography, phase, and element composition of the TiO2 and Cu-TiO2 coatings were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and energy-dispersive X-ray spectrometry （EDS）, respectively. Staphylococcus aureus （S. aureus） was selected to evaluate the antibacterial property of the Cu-TiO2 coatings, whereas osteoblastic MG63 cells were cultured on the coatings to investigate the biological activity. The obtained results demonstrated that Cu element was successfully incorporated into the porous nano-structured TiO2 coatings, which did not alter apparently the surface topography and phase composition of the coatings as compared to the Cu-free TiO2 coatings. Moreover, the antibacterial studies suggested that the Cu-incorporated TiO2 coatings could significantly inhibit the adhesion of S. aureus. In addition, the in vitro biological evaluation displayed that the adhesion, proliferation and differentiation of MG63 cells on the Cu-incorporated coatings were enhanced as compared to those on the Cu-free coatings and Ti plates. In conclusion, the innovative Cu-incorporated nano-structured TiO2 coatings on Ti substrate with excellent antibacterial property and biological activity are promising candidates for orthopedic implant.
基金Supported by the Guangdong Provincial Natural Science Foundation(No.2114050001527).
文摘Micro/nanoplastics(M/NPs)have become pervasive environmental pollutants,posing significant risks to human health through various exposure routes,including ingestion,inhalation,and direct contact.This review systematically examined the potential impacts of M/NPs on ocular health,focusing on exposure pathways,toxicological mechanisms,and resultant damage to the eye.Ocular exposure to M/NPs can occur via direct contact and oral ingestion,with the latter potentially leading to the penetration of particles through ocular biological barriers into ocular tissues.The review highlighted that M/NPs can induce adverse effects on the ocular surface,elevate intraocular pressure,and cause abnormalities in the vitreous and retina.Mechanistically,oxidative stress and inflammation are central to M/NP-induced ocular damage,with smaller particles often exhibiting greater toxicity.Overall,this review underscored the potential risks of M/NPs to ocular health and emphasized the need for further research to elucidate exposure mechanisms,toxicological pathways,and mitigation strategies.
基金financially supported by the National Key Research and Development Program(2022YFE0127400)the National Natural Science Foundation of China(52172040,52202041,and U23B2077)+1 种基金Taishan Scholar Project of Shandong Province(tsqn202211086,ts202208832,tsqnz20221118)the Fundamental Research Funds for the Central Universities(23CX06055A).
文摘Micro silicon(mSi)is a promising anode candidate for all-solid-state batteries due to its high specific capacity,low side reactions,and high tap density.However,silicon suffers from its poor electronic and ionic conductivity,which is particularly severe on a micro scale and in solid-state systems,leading to increased polarization and inferior electrochemical performance.Doping can broaden the transmission pathways and reduce the diffusion energy barrier for electrons and lithium ions.However,achieving effective,uniform doping in mSi is challenging due to its longer diffusion paths and higher energy barriers.Therefore,current doping research is primarily limited to nanosilicon.In this study,we successfully used a Joule-heating activated staged thermal treatment to achieve full-depth doping of germanium(Ge)in the mSi substrate.The Joule-heating process activated the mSi substrate,resulting in abundant vacancy defects that reduced the diffusion barrier of Ge into the silicon lattice and facilitated full-depth Ge doping.Surprisingly,the resulting Si-Ge anode exhibited significantly enhanced electrical conductivity(70 times).Meanwhile,the improved Li-ion conductivity in mSi and the reduced Young’s modulus enhance the electrode reaction kinetics and integrity after cycling.Ge-doped silicon anodes demonstrate excellent electrochemical performance when applied in sulfide solid-state half-cells and full-cells.This work provides substantial insights into the rational structural design of mSi alloyed anode materials,paving the way for the development of high-performance solid-state Li-ion batteries.
基金supported by Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2022QNRC001)the National Natural Science Foundation of China(No.52273053)the Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.21CGA41)。
文摘Extreme cold weather seriously harms human thermoregulatory system,necessitating high-performance insulating garments to maintain body temperature.However,as the core insulating layer,advanced fibrous materials always struggle to balance mechanical properties and thermal insulation,resulting in their inability to meet the demands for both washing resistance and personal protection.Herein,inspired by the natural spring-like structures of cucumber tendrils,a superelastic and washable micro/nanofibrous sponge(MNFS)based on biomimetic helical fibers is directly prepared utilizing multiple-jet electrospinning technology for high-performance thermal insulation.By regulating the conductivity of polyvinylidene fluoride solution,multiple-jet ejection and multiple-stage whipping of jets are achieved,and further control of phase separation rates enables the rapid solidification of jets to form spring-like helical fibers,which are directly entangled to assemble MNFS.The resulting MNFS exhibits superelasticity that can withstand large tensile strain(200%),1000 cyclic tensile or compression deformations,and retain good resilience even in liquid nitrogen(-196℃).Furthermore,the MNFS shows efficient thermal insulation with low thermal conductivity(24.85 mW m^(-1)K^(-1)),close to the value of dry air,and remains structural stability even after cyclic washing.This work offers new possibilities for advanced fibrous sponges in transportation,environmental,and energy applications.
基金supported by the National Natural Science Foundation of China(22168008,22378085)the Guangxi Natural Science Foundation(2024GXNSFDA010053)+1 种基金the Technology Development Project of Guangxi Bossco Environmental Protection Technology Co.,Ltd(202100039)Innovation Project of Guangxi Graduate Education(YCBZ2024065).
文摘Strategically coupling nanoparticle hybrids and internal thermosensitive molecular switches establishes an innovative paradigm for constructing micro/nanoscale-reconfigurable robots,facilitating energyefficient CO_(2) management in life-support systems of confined space.Here,a micro/nano-reconfigurable robot is constructed from the CO_(2) molecular hunters,temperature-sensitive molecular switch,solar photothermal conversion,and magnetically-driven function engines.The molecular hunters within the molecular extension state can capture 6.19 mmol g^(−1) of CO_(2) to form carbamic acid and ammonium bicarbonate.Interestingly,the molecular switch of the robot activates a molecular curling state that facilitates CO_(2) release through nano-reconfiguration,which is mediated by the temperature-sensitive curling of Pluronic F127 molecular chains during the photothermal desorption.Nano-reconfiguration of robot alters the amino microenvironment,including increasing surface electrostatic potential of the amino group and decreasing overall lowest unoccupied molecular orbital energy level.This weakened the nucleophilic attack ability of the amino group toward the adsorption product derivatives,thereby inhibiting the side reactions that generate hard-to-decompose urea structures,achieving the lowest regeneration temperature of 55℃ reported to date.The engine of the robot possesses non-contact magnetically-driven micro-reconfiguration capability to achieve efficient photothermal regeneration while avoiding local overheating.Notably,the robot successfully prolonged the survival time of mice in the sealed container by up to 54.61%,effectively addressing the issue of carbon suffocation in confined spaces.This work significantly enhances life-support systems for deep-space exploration,while stimulating innovations in sustainable carbon management technologies for terrestrial extreme environments.
基金financially supported by the China Scholarship Council(CSC)。
文摘Mine filling materials urgently need to improve mechanical properties and achieve low-carbon transformation.This study explores the mechanism of the synergistic effect of optimizing aggregate fractal grading and introducing CO_(2)nanobubble technology to improve the performance of cement-fly ash-based backfill materials(CFB).The properties including fluidity,setting time,uniaxial compressive strength,elastic modulus,porosity,microstructure and CO_(2)storage performance were systematically studied through methods such as fluidity evaluation,time test,uniaxial compression test,mercury intrusion porosimetry(MIP),scanning electron microscopy-energy dispersive spectroscopy analysis(SEM-EDS),and thermogravimetric-differential thermogravimetric analysis(TG-DTG).The experimental results show that the density and strength of the material are significantly improved under the synergistic effect of fractal dimension and CO_(2)nanobubbles.When the fractal dimension reaches 2.65,the mass ratio of coarse and fine aggregates reaches the optimal balance,and the structural density is greatly improved at the same time.At this time,the uniaxial compressive strength and elastic modulus reach their peak values,with increases of up to 13.46%and 27.47%,respectively.CO_(2)nanobubbles enhance the material properties by promoting hydration reaction and carbonization.At the microscopic level,CO_(2)nanobubble water promotes the formation of C-S-H(hydrated calcium silicate),C-A-S-H(hydrated calcium aluminium silicate)gel and CaCO_(3),which is the main way to enhance the performance.Thermogravimetric studies have shown that when the fractal dimension is 2.65,the dehydration of hydration products and the decarbonization process of CaCO_(3)are most obvious,and CO_(2)nanobubble water promotes the carbonization reaction,making it surpass the natural state.The CO_(2)sequestration quality of cement-fly ash-based materials treated with CO_(2)nanobubble water at different fractal dimensions increased by 12.4wt%to 99.8wt%.The results not only provide scientific insights for the design and implementation of low-carbon filling materials,but also provide a solid theoretical basis for strengthening green mining practices and promoting sustainable resource utilization.
基金the Deanship of Scientific Research at Northern Border University,Arar,Saudi Arabia,for funding this research work through the project number“NBU-FFR-2025-3623-11”.
文摘Modern power systems increasingly depend on interconnected microgrids to enhance reliability and renewable energy utilization.However,the high penetration of intermittent renewable sources often causes frequency deviations,voltage fluctuations,and poor reactive power coordination,posing serious challenges to grid stability.Conventional Interconnection FlowControllers(IFCs)primarily regulate active power flowand fail to effectively handle dynamic frequency variations or reactive power sharing in multi-microgrid networks.To overcome these limitations,this study proposes an enhanced Interconnection Flow Controller(e-IFC)that integrates frequency response balancing and an Interconnection Reactive Power Flow Controller(IRFC)within a unified adaptive control structure.The proposed e-IFC is implemented and analyzed in DIgSILENT PowerFactory to evaluate its performance under various grid disturbances,including frequency drops,load changes,and reactive power fluctuations.Simulation results reveal that the e-IFC achieves 27.4% higher active power sharing accuracy,19.6% lower reactive power deviation,and 18.2% improved frequency stability compared to the conventional IFC.The adaptive controller ensures seamless transitions between grid-connected and islanded modes and maintains stable operation even under communication delays and data noise.Overall,the proposed e-IFCsignificantly enhances active-reactive power coordination and dynamic stability in renewable-integrated multi-microgrid systems.Future research will focus on coupling the e-IFC with tertiary-level optimization frameworks and conducting hardware-in-the-loop validation to enable its application in large-scale smart microgrid environments.
基金supported by the National Natural Science Foundation of China(Grant No.51771233,52071346 and 51604104)China Postdoctoral Science Foundation(Grant No.2018M633164)+1 种基金Innovation-oriented Advanced Technology and Industrial Technology Program Project of Hunan Province(Grant No.2020SK2017)Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515110736)。
文摘Modulating the activation state and degree of macrophages still remains as a challenge for the topographical design of Ti-based implants.In this work,micro/nano-structured coatings were prepared on Ti substrates by micro-arc oxidation(MAO)and subsequent hydrothermal(HT)treatment.By varying the HT conditions,plate-like nano-structures with an average length of 80,440 or 780 nm were obtained on MAO-prepared micro-topographical surfaces.Depending on the dimensional features of nano-plates,the specimens were noted as Micro,Micro/Nano-180,Micro/Nano-440 and Micro/Nano-780,respectively.The in vitro results showed that the activation state and degree of macrophages could be effectively modulated by the micro/nano-structured surfaces with various dimensional features.Compared to the Micro surface,the Micro/Nano-180 surface activated both M1 and M2 phenotype in macrophages,while the Micro/Nano-440 and Micro/Nano-780 surfaces polarized macrophages to their M1 phenotype.The activation degree of M1 macrophages followed the trend:Micro<Micro/Nano-180<Micro/Nano-440<Micro/Nano-780.However,the osteogenic potential of the activated macrophages in response to various surfaces were in the order:Micro≈Micro/Nano-780<Micro/Nano-180<Micro/Nano-440.Together,the findings presented in this work indicate that engineering nano-structures with controllable dimensional features is a promising strategy to modulate macrophage activation state and degree.In addition,it is essential to determine the appropriate activation degree of M1 macrophages for enhanced osteogenesis.
