Micro/nano hierarchical structures could endow materials with various surface functions.However,the multilayer and multiscale characteristics of micro/nano hierarchical structures bring difficulties for their one step...Micro/nano hierarchical structures could endow materials with various surface functions.However,the multilayer and multiscale characteristics of micro/nano hierarchical structures bring difficulties for their one step and controllable fabrication.Accordingly,based on tip-based fabrication techniques,this study proposed a micro-amplitude vibration-assisted scratching method by introducing a periodic backward displacement into the conventional scratching process,which enabled the synchronous creation of the microscale V-groove and nanoscale ripples,i.e.a typical micro/nano hierarchical structure.The experiments and finite element modeling were employed to explore the formation process and mechanism of the micro/nano hierarchical structures.Being different from conventional cutting,this method was mainly based on the plow mechanism,and it could accurately replicate the shape of the indenter on the material surface.The microscale V-groove was formed due to the scratching action,and the nanoscale ripple was formed due to the extrusion action of the indenter on the microscale V-groove’s surface.Furthermore,the relationships between the processing parameters and the dimensions of the micro/nano hierarchical structures were established through experiments,and optimized processing parameters were determined to achieve regular micro/nano hierarchical structures.By this method,complex patterns constructed by various micro/nano hierarchical structures were fabricated on both flat and curved surfaces,achieving diverse surface structural colors.展开更多
Enzyme-powered micro/nanomotors(MNMs)(EMNMs)use natural enzymes to facilitate the decomposition of fuels,including hydrogen peroxide(H2O2),glucose,triglycerides,and urea to provide power.EMNMs can achieve self-propuls...Enzyme-powered micro/nanomotors(MNMs)(EMNMs)use natural enzymes to facilitate the decomposition of fuels,including hydrogen peroxide(H2O2),glucose,triglycerides,and urea to provide power.EMNMs can achieve self-propulsion through the in situ utilization of biofuels without additional fuels,exhibiting excellent biocompatibility and significant potential for application in the biomedical field.Compared with H_(2)O_(2),which may cause oxidative damage to the body,urea exhibits superior biosafety characteristics.Presently,urease-powered MNMs(UMNMs)have made notable progress in their applications in the biomedical field and have garnered considerable attention from researchers.In this review,we present the latest advancements in the biomedical field of UMNMs,primarily focusing on:1)diverse materials used for constructing the fundamental framework of motors;2)control of motor movement through the regulation of enzymatic reaction rates;and 3)research directions for the clinical application of motors,including in vivo imaging,biomarker detection,cancer treatment,optical therapy,overcoming biological barriers,antibacterial interventions,antithrombotic strategies,and gastric disease management.Despite showing immense potential in biomedical applications,there are still several challenges impeding its practical implementation,such as maintaining activity in the in vivo environment while accurately targeting specific sites to achieve the desired clinical therapeutic effects.展开更多
Micro aerial vehicles(MAVs)have flexibility and maneuverability,which can offer vast potential for applications in both civilian and military domains.Compared to Fixed-wing/Rotor-wing MAVs,Flapping Wing Micro Robots(F...Micro aerial vehicles(MAVs)have flexibility and maneuverability,which can offer vast potential for applications in both civilian and military domains.Compared to Fixed-wing/Rotor-wing MAVs,Flapping Wing Micro Robots(FWMRs)have garnered widespread attention among scientists due to their superior miniaturized aerodynamic theory,reduced noise,and enhanced resistance to disturbances in complex and diverse environments.Flying insects,it not only has remarkable flapping flight ability(wings),but also takeoff and landing habitat ability(legs).If the various functions of flying insects can be imitated,efficient biomimetic FWMRs can be produced.This paper provides a review of the flight kinematics,aerodynamics,and wing structural parameters of insects.Then,the traditional wings and folding wings of insect-inspired FWMRs were compared.The research progress in takeoff and landing of FWMRs was also summarized,and the future developments and challenges for insect-inspired FWMRs were discussed.展开更多
The prioritization of financial infrastructure construction serves as a crucial guarantee for the high-quality development of small and micro enterprises.However,resolving the financing challenges of small and micro e...The prioritization of financial infrastructure construction serves as a crucial guarantee for the high-quality development of small and micro enterprises.However,resolving the financing challenges of small and micro enterprises is not a task to be accomplished overnight.It necessitates the establishment of a long-term mechanism,the acceleration of financial innovation,the gradual enhancement of the vitality of micro-entities,and the creation of a stable and healthy economic development environment.Therefore,the author first analyzes the current financing situation of small and micro enterprises,as well as the problems they face during the process of financial innovation enabling small and micro enterprises to access financing and solve their financing difficulties,such as insufficient technical support,an imperfect risk control system,incomplete information disclosure,and a lack of credit data.Subsequently,targeted paths for financial innovation are proposed,aiming to offer suggestions for solving the financing problems of small and micro enterprises.展开更多
Microwave sensing technology has become increasingly widely applied in the biomedical field,playing a significant role in medical diagnosis,biological monitoring,and environmental warning.In recent years,the introduct...Microwave sensing technology has become increasingly widely applied in the biomedical field,playing a significant role in medical diagnosis,biological monitoring,and environmental warning.In recent years,the introduction of metamaterials has brought new possibilities and opportunities to microwave biosensors.This paper aims to explore the applications of microwave sensors in biosensing,with a particular emphasis on analyzing the crucial role of metamaterials in enhancing sensor performance and sensitivity.It provides a thorough examination of the fundamental principles,design strategies,fabrication techniques,and applications of microwave biosensors leveraging metamaterial enhancement.Moreover,it meticulously explores the latest applications spanning biomedical diagnostics,environmental monitoring,and food safety,shedding light on their transformative potential in healthcare,environmental sustainability,and food quality assurance.By delving into future research directions and confronting present challenges such as standardization and validation protocols,cost-effectiveness and scalability considerations and exploration of emerging applications,the paper provides a roadmap for advancing microwave biosensors with metamaterial enhancement,promising breakthroughs in multifaceted bioanalytical realms.展开更多
The designing and manufacturing of micro/nanoscale tools for delivery,diagnostic,and therapeutic are essential for their multiscale integration in the precision medicine field.Conventional three-dimensional(3D)printin...The designing and manufacturing of micro/nanoscale tools for delivery,diagnostic,and therapeutic are essential for their multiscale integration in the precision medicine field.Conventional three-dimensional(3D)printing approaches are not suitable for such kind of tools due to the accuracy limitation.Multiphoton polymerization(MPP)-based micro/nanomanufacturing is a noncontact,high-precision molding technology that has been widely used in the micro/nano field is a promising tool for micro/nanoscale related precision medicine.In this article the fundamentals of MPP-based technology and the required materials in precision medicine are overviewed.The biomedical applications in various scenarios are then summarized and categorized as delivery systems,microtissue modeling,surgery,and diagnosis.Finally,the existing challenges and future perspectives on MPP-based micro/nanomanufacturing for precision medicine are discussed,focusing on material design,process optimization,and practical applications to overcome its current limitations.展开更多
Over the past three decades,micro/nano science and technology have experienced rapid advancements as new materials and advanced devices have increasingly evolved towards high levels of integration and miniaturization....Over the past three decades,micro/nano science and technology have experienced rapid advancements as new materials and advanced devices have increasingly evolved towards high levels of integration and miniaturization.In this context,mechanical properties have emerged as critical parameters for evaluating the operational performance and longevity of materials and devices at the micro/nanoscale.展开更多
Microassembly platforms have attracted significant attention recently because of their potential for developing microsystems and devices for a wide range of applications.Despite their considerable poten-tial,existing ...Microassembly platforms have attracted significant attention recently because of their potential for developing microsystems and devices for a wide range of applications.Despite their considerable poten-tial,existing techniques are mainly used in laboratory research settings.This review provides an over-view of the fundamentals,techniques,and applications of microassemblies.Manipulation techniques based on magnetic,optical,acoustic fields,and mechanical systems are discussed,and control systems that rely on machine vision and force feedback are introduced.Additionally,recent applications of microassemblies in microstructure fabrication,microelectromechanical operation,and biomedical engi-neering are examined.This review also highlights unmet technical demands and emerging trends,as well as new research opportunities in this expanding field of research driven by allied technologies such as microrobotics.展开更多
Sn-based solder is a widely used interconnection material in the field of electronic packaging;however,the performance requirements for these solders are becoming increasingly demanding owing to the rapid development ...Sn-based solder is a widely used interconnection material in the field of electronic packaging;however,the performance requirements for these solders are becoming increasingly demanding owing to the rapid development in this area.In recent years,the addition of micro/nanoreinforcement phases to Sn-based solders has provided a solution to improve the intrinsic properties of the solders.This paper reviews the progress in Sn-based micro/nanoreinforced composite solders over the past decade.The types of reinforcement particles,preparation methods of the composite solders,and strengthening effects on the microstructure,wettability,melting point,mechanical properties,and corrosion resistance under different particle-addition levels are discussed and summarized.The mechanisms of performance enhancement are summarized based on material-strengthening effects such as grain refinement and second-phase dispersion strengthening.In addition,we discuss the current shortcomings of such composite solders and possible future improvements,thereby establishing a theoretical foundation for the future development of Sn-based solders.展开更多
Semisolid ZL101 aluminum slurry was prepared by a micro fused-casting process.The nozzle temperature has great effects on the microstructure and mechanical properties,which are primarily influenced through changing co...Semisolid ZL101 aluminum slurry was prepared by a micro fused-casting process.The nozzle temperature has great effects on the microstructure and mechanical properties,which are primarily influenced through changing cooling conditions of the fused-casting area.With the decline of nozzle temperatures,the microstructure of semisolid ZL101 aluminum slurry tends to be more homogeneous,delivering smaller grains.Temperatures of liquids and solids were measured by differential scanning calorimetry(DSC).Distribution and characteristics of microstructure were examined by scanning electron microscopy(SEM)equipped with energy dispersive spectrometer(EDS)and optical microscope(OM).It is found that uniform shape and good grain size are observed for semisolid samples fabricated by micro fused-casting under conditions including nozzle temperature of 592℃,bucket temperature of 600℃,stirring velocity of 600 r/min and channel diameter of 3 mm.Due to the smaller average grain size of 53μm and shape factor of 0.71 for the fine grains,the ultrahigh average tensile strength and Vickers hardness can reach(181±1.25)MPa and(87.95±1.18)HV for the optimized semisolid ZL101 aluminum slurry,respectively.展开更多
In the present study,two-layered stainless steel-copper composites with a thickness of 50μm were initially subjected to annealing at 800,900 and 1000℃for 5 min,respectively,to achieve diverse microstructural feature...In the present study,two-layered stainless steel-copper composites with a thickness of 50μm were initially subjected to annealing at 800,900 and 1000℃for 5 min,respectively,to achieve diverse microstructural features.Then the influence of annealing temperature on the formability of stainless steel-copper composites and the quality of micro composite cups manufactured by micro deep drawing(MDD)were investigated,and the underlying mechanism was analyzed.Three finite element(FE)models,including basic FE model,Voronoi FE model and surface morphological FE model,were developed to analyze the forming performance of stainless steel-copper composites during MDD.The results show that the stainless steel-copper composites annealed at 900℃possess the best plasticity owing to the homogeneous and refined microstructure in both stainless steel and copper matrixes,and the micro composite cup with specimen annealed at 900℃exhibits a uniform wall thickness as well as high surface quality with the fewest wrinkles.The results obtained from the surface morphological FE model considering material inhomogeneity and surface morphology of the composites are the closest to the experimental results compared to the basic and Voronoi FE model.During MDD process,the drawing forces decrease with increasing annealing temperature as a consequence of the strength reduction.展开更多
Micro/nanorobots have exhibited excellent application potential in the biomedical field,such as drug delivery,minimally invasive surgery,and bio-sensing.Furthermore,in order to achieve practical application,it is esse...Micro/nanorobots have exhibited excellent application potential in the biomedical field,such as drug delivery,minimally invasive surgery,and bio-sensing.Furthermore,in order to achieve practical application,it is essential for swimming micro/nanorobots to navigate towards specific targets or adjust their speed and morphology in complete environments.The navigation of swimming micro/nanorobots with temporal and spatial precision is critical for fulfilling the demand of applications.Here,we introduced a fully integrated wearable control system for micro/nanorobots navigation and manipulation,which is composed of a multifunctional sensor array,an artificial intelligence(AI)planner,and a magnetic field generator.The sensor array could perceive real-time changes in gestures,wrist rotation,and acoustic signals.AI planner based on machine learning offers adaptive path planning in response to dynamically changing signals to generate magnetic fields for the on-demand manipulation of micro/nanorobots.Such a novel,feasible control strategy was validated in the biological experiment in which cancer cells were targeted and killed by photothermal therapy using micro/nanorobots and integrated control platform.This wearable control system could play a crucial role in future intelligent medical applications and could be easily reconfigured toward other medical robots’control.展开更多
Micro(nano)plastics,as an emerging environmental pollutant,are gradually discovered in hyporheic zones and groundwaterworldwide.Recent studies have focused on the origin and spatial/temporal distribution of micro(nano...Micro(nano)plastics,as an emerging environmental pollutant,are gradually discovered in hyporheic zones and groundwaterworldwide.Recent studies have focused on the origin and spatial/temporal distribution of micro(nano)plastics in regional groundwater,together with the influence of their properties and effects of environmental factors on their transport.However,the transport of micro(nano)plastics in the whole hyporheic zone-groundwater system and the behavior of co-existing substances still lack a complete theoretical interpretation.To provide systematic theoretical support for that,this review summarizes the current pollution status of micro(nano)plastics in the hyporheic zone-groundwater system,provides a comprehensive introduction of their sources and fate,and classifies the transport mechanisms into mechanical transport,physicochemical transport and biological processes assisted transport fromthe perspectives ofmechanical stress,physicochemical reactions,and bioturbation,respectively.Ultimately,this review proposes to advance the understanding of the multi-dimensional hydrosphere transport of micro(nano)plastics centered on groundwater,themicroorganisms-mediated synergistic transformation and co-transport involving the intertidal circulation.Overall,this review systematically dissects the presence and transport cycles of micro(nano)plastics within the hyporheic zone-groundwater system and proposes prospects for future studies based on the limitations of current studies.展开更多
The mechanical behavior of cohesive soil is sensitized to drying-wetting cycles under confinements.However,the hydromechanical coupling effect has not been considered in current constitutive models.A macro-micro analy...The mechanical behavior of cohesive soil is sensitized to drying-wetting cycles under confinements.However,the hydromechanical coupling effect has not been considered in current constitutive models.A macro-micro analysis scheme is proposed in this paper to investigate the soil deformation behavior under the coupling of stress and drying-wetting cycles.A new device is developed based on CT(computerized tomography)workstation to apply certain normal and shear stresses on a soil specimen during drying-wetting cycles.A series of tests are conducted on a type of loess with various coupling of stress paths and drying-wetting cycles.At macroscopic level,stress sensor and laser sensor are used to acquire stress and strain,respectively.The shear and volumetric strain increase during the first few drying-wetting cycles and then become stable.The increase of the shear stress level or confining pressure would cause higher increase rate and the value of shear strain in the process of drying-wetting cycles.At microscopic level,the grayscale value(GSV)of CT scanning image is characterized as the proportion of soil particles to voids.A fabric state parameter is proposed to characterize soil microstructures under the influence of stress and drying-wetting cycle.Test results indicate that the macroand micro-responses show high consistence and relevance.The stress and drying-wetting cycles would both induce collapse of the soil microstructure,which dominants degradation of the soil mechanical properties.The evolution of the macro-mechanical property of soil exhibits a positive linear relationship with the micro-evolution of the fabric state parameter.展开更多
When a planet is ejected from its star-planet system due to dynamical interactions,its satellite may remain gravitationally bound to the planet.The Chinese Space Station Telescope(CSST)will be capable of detecting a l...When a planet is ejected from its star-planet system due to dynamical interactions,its satellite may remain gravitationally bound to the planet.The Chinese Space Station Telescope(CSST)will be capable of detecting a large number of low-mass free-floating planet events(FFPs)from a bulge microlensing survey.We assess the feasibility of detecting satellites(a.k.a.,exomoons)orbiting FFPs by simulating CSST light curves and calculating the detection efficiency as a function of satellite-to-planet mass ratios(q)and projected separations(s)in units of the Einstein radius.For a Neptune-class FFP in the Galactic disk with a Sun-like star as the microlensed source,CSST can detect Earth-mass satellites over a decade of separations(∼0.01-0.1 au)and has sensitivity down to Moon-mass satellites(q∼10^(−3))at s^(∼1).CSST also has some sensitivity to detect Moon-mass satellites at s∼2(∼0.02 au)orbiting an Earth-mass FFP in the disk.CSST has substantially reduced sensitivity for detecting satellites when the source star is an M dwarf,compared to a Sun-like source.We also calculate the satellite detection efficiency for the dedicated microlensing survey of the Roman Space Telescope(Roman),which demonstrates greater sensitivity than CSST,particularly for M-dwarf sources.Notably,some of the Neptune-Earth systems detectable by CSST and Roman may exhibit significant tidal heating.展开更多
Through the demand analysis of emergency power supply construction, waterfall noise reduction treatment, and utilization of residual pressure resources, combined with water resources and industrial infrastructure cond...Through the demand analysis of emergency power supply construction, waterfall noise reduction treatment, and utilization of residual pressure resources, combined with water resources and industrial infrastructure conditions, this paper proposes the significance of micro hydropower station construction. However, micro hydropower stations face issues such as insufficient construction standardization, prominent safety hazards, lack of specialized standards, and the need for improved planning and design. Therefore, this paper analyzes and discusses the constraints and improvement summaries in the entire construction process of micro hydropower stations from aspects including guidance of standard formulation, rationality of planning and design, and innovation of new product applications.展开更多
Magnesium is distinguished by its highly anisotropic inelastic deformation involving a profuse activity of deformation twinning.Instrumented micro/nano-indentation technique has been widely applied to characterize the...Magnesium is distinguished by its highly anisotropic inelastic deformation involving a profuse activity of deformation twinning.Instrumented micro/nano-indentation technique has been widely applied to characterize the mechanical properties of magnesium,typically through the analysis of the indentation load-depth response,surface topography,and less commonly,the post-mortem microstructure within the bulk material.However,experimental limitations prevent the real-time observation of the evolving microstructure.To bridge this gap,we employ a recently-developed finite-strain model that couples the phase-field method and conventional crystal plasticity to simulate the evolution of the indentation-induced twin microstructure and its interaction with plastic slip in a magnesium single-crystal.Particular emphasis is placed on two aspects:orientation-dependent inelastic deformation and indentation size effects.Several outcomes of our 2D computational study are consistent with prior experimental observations.Chief among them is the intricate morphology of twin microstructure obtained at large spatial scales,which,to our knowledge,represents a level of detail that has not been captured in previous modeling studies.To further elucidate on size effects,we extend the model by incorporating gradient-enhanced crystal plasticity,and re-examine the notion of‘smaller is stronger’.The corresponding results underscore the dominant influence of gradient plasticity over the interfacial energy of twin boundaries in governing the size-dependent mechanical response.展开更多
基金supported by the Jilin Province Key Research and Development Plan Project(20240302066GX)the National Natural Science Foundation of China(Grant No.52075221)the Fundamental Research Funds for the Central Universities(2023-JCXK-02)。
文摘Micro/nano hierarchical structures could endow materials with various surface functions.However,the multilayer and multiscale characteristics of micro/nano hierarchical structures bring difficulties for their one step and controllable fabrication.Accordingly,based on tip-based fabrication techniques,this study proposed a micro-amplitude vibration-assisted scratching method by introducing a periodic backward displacement into the conventional scratching process,which enabled the synchronous creation of the microscale V-groove and nanoscale ripples,i.e.a typical micro/nano hierarchical structure.The experiments and finite element modeling were employed to explore the formation process and mechanism of the micro/nano hierarchical structures.Being different from conventional cutting,this method was mainly based on the plow mechanism,and it could accurately replicate the shape of the indenter on the material surface.The microscale V-groove was formed due to the scratching action,and the nanoscale ripple was formed due to the extrusion action of the indenter on the microscale V-groove’s surface.Furthermore,the relationships between the processing parameters and the dimensions of the micro/nano hierarchical structures were established through experiments,and optimized processing parameters were determined to achieve regular micro/nano hierarchical structures.By this method,complex patterns constructed by various micro/nano hierarchical structures were fabricated on both flat and curved surfaces,achieving diverse surface structural colors.
基金supported by the National Natural Science Foundation of China(Grant No.:82372102).
文摘Enzyme-powered micro/nanomotors(MNMs)(EMNMs)use natural enzymes to facilitate the decomposition of fuels,including hydrogen peroxide(H2O2),glucose,triglycerides,and urea to provide power.EMNMs can achieve self-propulsion through the in situ utilization of biofuels without additional fuels,exhibiting excellent biocompatibility and significant potential for application in the biomedical field.Compared with H_(2)O_(2),which may cause oxidative damage to the body,urea exhibits superior biosafety characteristics.Presently,urease-powered MNMs(UMNMs)have made notable progress in their applications in the biomedical field and have garnered considerable attention from researchers.In this review,we present the latest advancements in the biomedical field of UMNMs,primarily focusing on:1)diverse materials used for constructing the fundamental framework of motors;2)control of motor movement through the regulation of enzymatic reaction rates;and 3)research directions for the clinical application of motors,including in vivo imaging,biomarker detection,cancer treatment,optical therapy,overcoming biological barriers,antibacterial interventions,antithrombotic strategies,and gastric disease management.Despite showing immense potential in biomedical applications,there are still several challenges impeding its practical implementation,such as maintaining activity in the in vivo environment while accurately targeting specific sites to achieve the desired clinical therapeutic effects.
基金supported by the National Natural Science Foundation of China(grant numbers 52305321 and 62273246)The Natural Science Foundation of Jiangsu Province(BK20230496)+3 种基金China Postdoctoral Science Foundation Funded Project(2023M732536 and 2024T170630)Jiangsu Province Excellence Postdoctoral Program(2023ZB218)The National Key R&D Program of China(2022YFB4702202)The Jiangsu Provincial Key Technology R&D Program(BE2021009-02).
文摘Micro aerial vehicles(MAVs)have flexibility and maneuverability,which can offer vast potential for applications in both civilian and military domains.Compared to Fixed-wing/Rotor-wing MAVs,Flapping Wing Micro Robots(FWMRs)have garnered widespread attention among scientists due to their superior miniaturized aerodynamic theory,reduced noise,and enhanced resistance to disturbances in complex and diverse environments.Flying insects,it not only has remarkable flapping flight ability(wings),but also takeoff and landing habitat ability(legs).If the various functions of flying insects can be imitated,efficient biomimetic FWMRs can be produced.This paper provides a review of the flight kinematics,aerodynamics,and wing structural parameters of insects.Then,the traditional wings and folding wings of insect-inspired FWMRs were compared.The research progress in takeoff and landing of FWMRs was also summarized,and the future developments and challenges for insect-inspired FWMRs were discussed.
文摘The prioritization of financial infrastructure construction serves as a crucial guarantee for the high-quality development of small and micro enterprises.However,resolving the financing challenges of small and micro enterprises is not a task to be accomplished overnight.It necessitates the establishment of a long-term mechanism,the acceleration of financial innovation,the gradual enhancement of the vitality of micro-entities,and the creation of a stable and healthy economic development environment.Therefore,the author first analyzes the current financing situation of small and micro enterprises,as well as the problems they face during the process of financial innovation enabling small and micro enterprises to access financing and solve their financing difficulties,such as insufficient technical support,an imperfect risk control system,incomplete information disclosure,and a lack of credit data.Subsequently,targeted paths for financial innovation are proposed,aiming to offer suggestions for solving the financing problems of small and micro enterprises.
基金support from the National Key R&D Program of China(Grant No.2021YFC3002204)the National Natural Science Foundation of China(Grant No.U2233206)。
文摘Microwave sensing technology has become increasingly widely applied in the biomedical field,playing a significant role in medical diagnosis,biological monitoring,and environmental warning.In recent years,the introduction of metamaterials has brought new possibilities and opportunities to microwave biosensors.This paper aims to explore the applications of microwave sensors in biosensing,with a particular emphasis on analyzing the crucial role of metamaterials in enhancing sensor performance and sensitivity.It provides a thorough examination of the fundamental principles,design strategies,fabrication techniques,and applications of microwave biosensors leveraging metamaterial enhancement.Moreover,it meticulously explores the latest applications spanning biomedical diagnostics,environmental monitoring,and food safety,shedding light on their transformative potential in healthcare,environmental sustainability,and food quality assurance.By delving into future research directions and confronting present challenges such as standardization and validation protocols,cost-effectiveness and scalability considerations and exploration of emerging applications,the paper provides a roadmap for advancing microwave biosensors with metamaterial enhancement,promising breakthroughs in multifaceted bioanalytical realms.
基金the National Natural Science Foundation of China(52275294)the National Key Research and Development Program of China(2018YFA0703000).
文摘The designing and manufacturing of micro/nanoscale tools for delivery,diagnostic,and therapeutic are essential for their multiscale integration in the precision medicine field.Conventional three-dimensional(3D)printing approaches are not suitable for such kind of tools due to the accuracy limitation.Multiphoton polymerization(MPP)-based micro/nanomanufacturing is a noncontact,high-precision molding technology that has been widely used in the micro/nano field is a promising tool for micro/nanoscale related precision medicine.In this article the fundamentals of MPP-based technology and the required materials in precision medicine are overviewed.The biomedical applications in various scenarios are then summarized and categorized as delivery systems,microtissue modeling,surgery,and diagnosis.Finally,the existing challenges and future perspectives on MPP-based micro/nanomanufacturing for precision medicine are discussed,focusing on material design,process optimization,and practical applications to overcome its current limitations.
文摘Over the past three decades,micro/nano science and technology have experienced rapid advancements as new materials and advanced devices have increasingly evolved towards high levels of integration and miniaturization.In this context,mechanical properties have emerged as critical parameters for evaluating the operational performance and longevity of materials and devices at the micro/nanoscale.
基金supported by Shanghai Municipal Science and Technology Major Project(2021SHZDZX)also in part supported by the Science and Technology Commission of Shanghai Municipality(20DZ2220400).
文摘Microassembly platforms have attracted significant attention recently because of their potential for developing microsystems and devices for a wide range of applications.Despite their considerable poten-tial,existing techniques are mainly used in laboratory research settings.This review provides an over-view of the fundamentals,techniques,and applications of microassemblies.Manipulation techniques based on magnetic,optical,acoustic fields,and mechanical systems are discussed,and control systems that rely on machine vision and force feedback are introduced.Additionally,recent applications of microassemblies in microstructure fabrication,microelectromechanical operation,and biomedical engi-neering are examined.This review also highlights unmet technical demands and emerging trends,as well as new research opportunities in this expanding field of research driven by allied technologies such as microrobotics.
基金financially supported by the State Key Laboratory for Mechanical Behavior of Materials,China(No.202325012)the National Natural Science Foundation of China(No.U21A20128).
文摘Sn-based solder is a widely used interconnection material in the field of electronic packaging;however,the performance requirements for these solders are becoming increasingly demanding owing to the rapid development in this area.In recent years,the addition of micro/nanoreinforcement phases to Sn-based solders has provided a solution to improve the intrinsic properties of the solders.This paper reviews the progress in Sn-based micro/nanoreinforced composite solders over the past decade.The types of reinforcement particles,preparation methods of the composite solders,and strengthening effects on the microstructure,wettability,melting point,mechanical properties,and corrosion resistance under different particle-addition levels are discussed and summarized.The mechanisms of performance enhancement are summarized based on material-strengthening effects such as grain refinement and second-phase dispersion strengthening.In addition,we discuss the current shortcomings of such composite solders and possible future improvements,thereby establishing a theoretical foundation for the future development of Sn-based solders.
基金Funded by the Natural Science Foundation of Henan Province(No.252300420256)。
文摘Semisolid ZL101 aluminum slurry was prepared by a micro fused-casting process.The nozzle temperature has great effects on the microstructure and mechanical properties,which are primarily influenced through changing cooling conditions of the fused-casting area.With the decline of nozzle temperatures,the microstructure of semisolid ZL101 aluminum slurry tends to be more homogeneous,delivering smaller grains.Temperatures of liquids and solids were measured by differential scanning calorimetry(DSC).Distribution and characteristics of microstructure were examined by scanning electron microscopy(SEM)equipped with energy dispersive spectrometer(EDS)and optical microscope(OM).It is found that uniform shape and good grain size are observed for semisolid samples fabricated by micro fused-casting under conditions including nozzle temperature of 592℃,bucket temperature of 600℃,stirring velocity of 600 r/min and channel diameter of 3 mm.Due to the smaller average grain size of 53μm and shape factor of 0.71 for the fine grains,the ultrahigh average tensile strength and Vickers hardness can reach(181±1.25)MPa and(87.95±1.18)HV for the optimized semisolid ZL101 aluminum slurry,respectively.
基金Projects(51975398,52105392)supported by the National Natural Science Foundation of ChinaProject(YDZJSX2021A006)supported by the Central Government Guided Local Science and Technology Development Fund Project,China+1 种基金Project(20210035)supported by the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province,ChinaProject(2020-037)supported by the Fund Program for the Research Project Supported by Shanxi Scholarship Council,China。
文摘In the present study,two-layered stainless steel-copper composites with a thickness of 50μm were initially subjected to annealing at 800,900 and 1000℃for 5 min,respectively,to achieve diverse microstructural features.Then the influence of annealing temperature on the formability of stainless steel-copper composites and the quality of micro composite cups manufactured by micro deep drawing(MDD)were investigated,and the underlying mechanism was analyzed.Three finite element(FE)models,including basic FE model,Voronoi FE model and surface morphological FE model,were developed to analyze the forming performance of stainless steel-copper composites during MDD.The results show that the stainless steel-copper composites annealed at 900℃possess the best plasticity owing to the homogeneous and refined microstructure in both stainless steel and copper matrixes,and the micro composite cup with specimen annealed at 900℃exhibits a uniform wall thickness as well as high surface quality with the fewest wrinkles.The results obtained from the surface morphological FE model considering material inhomogeneity and surface morphology of the composites are the closest to the experimental results compared to the basic and Voronoi FE model.During MDD process,the drawing forces decrease with increasing annealing temperature as a consequence of the strength reduction.
基金supported by the National Key Research and Development Program(2022YFB4701700)National Excellent Youth Science Fund Project of the National Natural Science Foundation of China(52322502)+6 种基金the National Outstanding Youth Science Fund Project of National Natural Science Foundation of China(52025054)National Natural Science Foundation of China(52175009),Postdoctoral Fellowship Program of CPSF(GZC20232498)Postdoctoral Innovative Talents in Shandong Province(SDBX2023011)China Postdoctoral Science Foundation Grant(2023M733341)Key R&D Program of Shandong Province,China(2021ZLGX04)National Heilongjiang Providence Nature Science Foundation of China(YQ2022E022)Fundamental Research Funds for the Central Universities。
文摘Micro/nanorobots have exhibited excellent application potential in the biomedical field,such as drug delivery,minimally invasive surgery,and bio-sensing.Furthermore,in order to achieve practical application,it is essential for swimming micro/nanorobots to navigate towards specific targets or adjust their speed and morphology in complete environments.The navigation of swimming micro/nanorobots with temporal and spatial precision is critical for fulfilling the demand of applications.Here,we introduced a fully integrated wearable control system for micro/nanorobots navigation and manipulation,which is composed of a multifunctional sensor array,an artificial intelligence(AI)planner,and a magnetic field generator.The sensor array could perceive real-time changes in gestures,wrist rotation,and acoustic signals.AI planner based on machine learning offers adaptive path planning in response to dynamically changing signals to generate magnetic fields for the on-demand manipulation of micro/nanorobots.Such a novel,feasible control strategy was validated in the biological experiment in which cancer cells were targeted and killed by photothermal therapy using micro/nanorobots and integrated control platform.This wearable control system could play a crucial role in future intelligent medical applications and could be easily reconfigured toward other medical robots’control.
基金supported by the National Natural Science Foundation of China(Nos.22036001,42342057,and 22236006).
文摘Micro(nano)plastics,as an emerging environmental pollutant,are gradually discovered in hyporheic zones and groundwaterworldwide.Recent studies have focused on the origin and spatial/temporal distribution of micro(nano)plastics in regional groundwater,together with the influence of their properties and effects of environmental factors on their transport.However,the transport of micro(nano)plastics in the whole hyporheic zone-groundwater system and the behavior of co-existing substances still lack a complete theoretical interpretation.To provide systematic theoretical support for that,this review summarizes the current pollution status of micro(nano)plastics in the hyporheic zone-groundwater system,provides a comprehensive introduction of their sources and fate,and classifies the transport mechanisms into mechanical transport,physicochemical transport and biological processes assisted transport fromthe perspectives ofmechanical stress,physicochemical reactions,and bioturbation,respectively.Ultimately,this review proposes to advance the understanding of the multi-dimensional hydrosphere transport of micro(nano)plastics centered on groundwater,themicroorganisms-mediated synergistic transformation and co-transport involving the intertidal circulation.Overall,this review systematically dissects the presence and transport cycles of micro(nano)plastics within the hyporheic zone-groundwater system and proposes prospects for future studies based on the limitations of current studies.
基金funded by National Key R&D Program of China(Grant No.2023YFC3007001)Beijing Natural Science Foundation(Grant No.8244053)China Postdoctoral Science Foundation(Grant No.2024M754065).
文摘The mechanical behavior of cohesive soil is sensitized to drying-wetting cycles under confinements.However,the hydromechanical coupling effect has not been considered in current constitutive models.A macro-micro analysis scheme is proposed in this paper to investigate the soil deformation behavior under the coupling of stress and drying-wetting cycles.A new device is developed based on CT(computerized tomography)workstation to apply certain normal and shear stresses on a soil specimen during drying-wetting cycles.A series of tests are conducted on a type of loess with various coupling of stress paths and drying-wetting cycles.At macroscopic level,stress sensor and laser sensor are used to acquire stress and strain,respectively.The shear and volumetric strain increase during the first few drying-wetting cycles and then become stable.The increase of the shear stress level or confining pressure would cause higher increase rate and the value of shear strain in the process of drying-wetting cycles.At microscopic level,the grayscale value(GSV)of CT scanning image is characterized as the proportion of soil particles to voids.A fabric state parameter is proposed to characterize soil microstructures under the influence of stress and drying-wetting cycle.Test results indicate that the macroand micro-responses show high consistence and relevance.The stress and drying-wetting cycles would both induce collapse of the soil microstructure,which dominants degradation of the soil mechanical properties.The evolution of the macro-mechanical property of soil exhibits a positive linear relationship with the micro-evolution of the fabric state parameter.
基金supported by the National Natural Science Foundation of China(grant No.12133005)the China Manned Space Program with grant No.CMS-CSST-2025-A16.S.D.acknowledges the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘When a planet is ejected from its star-planet system due to dynamical interactions,its satellite may remain gravitationally bound to the planet.The Chinese Space Station Telescope(CSST)will be capable of detecting a large number of low-mass free-floating planet events(FFPs)from a bulge microlensing survey.We assess the feasibility of detecting satellites(a.k.a.,exomoons)orbiting FFPs by simulating CSST light curves and calculating the detection efficiency as a function of satellite-to-planet mass ratios(q)and projected separations(s)in units of the Einstein radius.For a Neptune-class FFP in the Galactic disk with a Sun-like star as the microlensed source,CSST can detect Earth-mass satellites over a decade of separations(∼0.01-0.1 au)and has sensitivity down to Moon-mass satellites(q∼10^(−3))at s^(∼1).CSST also has some sensitivity to detect Moon-mass satellites at s∼2(∼0.02 au)orbiting an Earth-mass FFP in the disk.CSST has substantially reduced sensitivity for detecting satellites when the source star is an M dwarf,compared to a Sun-like source.We also calculate the satellite detection efficiency for the dedicated microlensing survey of the Roman Space Telescope(Roman),which demonstrates greater sensitivity than CSST,particularly for M-dwarf sources.Notably,some of the Neptune-Earth systems detectable by CSST and Roman may exhibit significant tidal heating.
文摘Through the demand analysis of emergency power supply construction, waterfall noise reduction treatment, and utilization of residual pressure resources, combined with water resources and industrial infrastructure conditions, this paper proposes the significance of micro hydropower station construction. However, micro hydropower stations face issues such as insufficient construction standardization, prominent safety hazards, lack of specialized standards, and the need for improved planning and design. Therefore, this paper analyzes and discusses the constraints and improvement summaries in the entire construction process of micro hydropower stations from aspects including guidance of standard formulation, rationality of planning and design, and innovation of new product applications.
文摘Magnesium is distinguished by its highly anisotropic inelastic deformation involving a profuse activity of deformation twinning.Instrumented micro/nano-indentation technique has been widely applied to characterize the mechanical properties of magnesium,typically through the analysis of the indentation load-depth response,surface topography,and less commonly,the post-mortem microstructure within the bulk material.However,experimental limitations prevent the real-time observation of the evolving microstructure.To bridge this gap,we employ a recently-developed finite-strain model that couples the phase-field method and conventional crystal plasticity to simulate the evolution of the indentation-induced twin microstructure and its interaction with plastic slip in a magnesium single-crystal.Particular emphasis is placed on two aspects:orientation-dependent inelastic deformation and indentation size effects.Several outcomes of our 2D computational study are consistent with prior experimental observations.Chief among them is the intricate morphology of twin microstructure obtained at large spatial scales,which,to our knowledge,represents a level of detail that has not been captured in previous modeling studies.To further elucidate on size effects,we extend the model by incorporating gradient-enhanced crystal plasticity,and re-examine the notion of‘smaller is stronger’.The corresponding results underscore the dominant influence of gradient plasticity over the interfacial energy of twin boundaries in governing the size-dependent mechanical response.
