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
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
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 rapid evolution of laser micro/nano-manufacturing techniques has transformed precision manufacturing,enabling the creation of complex micro/nano-structures.These techniques are crucial for multiple industries,incl...The rapid evolution of laser micro/nano-manufacturing techniques has transformed precision manufacturing,enabling the creation of complex micro/nano-structures.These techniques are crucial for multiple industries,including electronics,photonics,and biomedical engineering,owing to their unmatched precision and versatility.The ability to manipulate materials at such scales has unlocked new possibilities for innovation,thereby facilitating the development of advanced components and devices with enhanced performance and functionalities.展开更多
Able to precisely control and manipulate materials'states at micro/nano-scale level,femtosecond(fs)laser micro/nano processing technology has undergone tremendous development over the past three decades.Free-formi...Able to precisely control and manipulate materials'states at micro/nano-scale level,femtosecond(fs)laser micro/nano processing technology has undergone tremendous development over the past three decades.Free-forming three-dimensional(3D)microscale functional devices and inducing fascinating and unique physical or chemical phenomena have granted this technology powerful versatility that no other technology can match.As this technology advances rapidly in various fields of application,some key challenges have emerged and remain to be urgently addressed.This review firstly introduces the fundamental principles for understanding how fs laser pulses interact with materials and the associated unique phenomena in section 2.Then micro/nano-fabrication in transparent materials by fs laser processing is presented in section 3.Thereafter,several high efficiency/throughput fabrication methods as well as pulse-shaping techniques are listed in sections 4 and 5 reviews four-dimensional(4D)and nanoscale printing realized by fs laser processing technology.Special attention is paid to the heterogeneous integration(HI)of functional materials enabled by fs laser processing in section 6.Several intriguing examples of 3D functional micro-devices created by fs laser-based manufacturing methods such as microfluidics,lab-on-chip,micro-optics,micro-mechanics,micro-electronics,micro-bots and micro-biodevices are reviewed in section 7.Finally,a summary of the review and a perspective are proposed to explore the challenges and future opportunities for further betterment of fs laser micro/nano processing technology.展开更多
Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity ...Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.展开更多
The development of precise and sensitive electrophysiological recording platforms holds the utmost importance for research in the fields of cardiology and neuroscience.In recent years,active micro/nano-bioelectronic d...The development of precise and sensitive electrophysiological recording platforms holds the utmost importance for research in the fields of cardiology and neuroscience.In recent years,active micro/nano-bioelectronic devices have undergone significant advancements,thereby facilitating the study of electrophysiology.The distinctive configuration and exceptional functionality of these active micro-nano-collaborative bioelectronic devices offer the potential for the recording of high-fidelity action potential signals on a large scale.In this paper,we review three-dimensional active nano-transistors and planar active micro-transistors in terms of their applications in electroexcitable cells,focusing on the evaluation of the effects of active micro/nano-bioelectronic devices on electrophysiological signals.Looking forward to the possibilities,challenges,and wide prospects of active micro-nano-devices,we expect to advance their progress to satisfy the demands of theoretical investigations and medical implementations within the domains of cardiology and neuroscience research.展开更多
The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of...The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.展开更多
The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fi...The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fiber(CF)plies to form thin interleaving,and various mass proportions of IT-MNASF were designed to discuss the reinforcing effect on the BCFRP heterogeneous composites.The results of three points bending tests showed that flexural strength and energy absorption of 4wt%IT-MNASF reinforced BCFRP heterogeneous composites had been improved by 32.4%and 134.4%respectively compared with that of unreinforced specimens.The 4wt%IT-MNASF reinforced BCFRP specimens showed both a greater strength and a lower cost(reduced by 31%around)than that of plain CFRP composites.X-ray micro-computed tomography scanning results exhibited that the delamination-dominated failure of plain BCFRP composites was changed into multi-layer BF and CF fabrics damage.The reinforcing mechanism revealed that the introduced IT-MNASF could construct quasi-vertical fiber bridging,and it was used as"mechanical claws"to grasp adjacent fiber layers for creating a stronger mechanical interlocking,and this effectively improved resin-rich region and interfacial transition region at the interlayers.The simple and effective IT-MNASF interleaving technique was very successful in low-cost and high-strength development of BCFRP heterogeneous composites.展开更多
The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transitio...The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transition region,and the flexible fiber bridging claws of MNSAF were constructed to grasp the adjacent layers for stronger interlaminar bond.The lowvelocity impact results show that the MNSAF could improve the impact resistance of BFRP composites.The compression test results demonstrate that the compressive strength and the residual compressive strength after impact of MNSAF-reinforced BFRP composites were greater than those of unreinforced one,exhibiting the greatest 56.2% and 73.3% increments respectively for BFRP composites improved by 4wt%MNSAF.X-ray micro-computed tomography scanning results indicate that the“fiber bridging claws”contributed to better mechanical interlocking to inhibit the crack generation and propagation under impact and compression load,and the original delamination-dominated failure of unreinforced BFRP composites was altered into sheardominated failure of MNSAF-reinforced BFRP composites.Overall,the MNSAF interleaving might be an effective method in manufacturing high-performance laminated fiber in industrial production.展开更多
Micro- and nano-plastics (MNPs) are tiny plastic particles resulting from plastic product degradation. Soil MNPs have been identified as potential influential factors affecting various soil properties and crop biomass...Micro- and nano-plastics (MNPs) are tiny plastic particles resulting from plastic product degradation. Soil MNPs have been identified as potential influential factors affecting various soil properties and crop biomass productivity. This mini-review provides a synthesis of recent findings concerning their effects on soil physicochemical properties, microorganisms, organic carbon content, soil nutrients, greenhouse gas emissions, soil fauna, and their impacts on plant ecophysiology, growth, and production. The results indicate that MNPs may markedly impede soil aggregation ability, increase porosity, decrease soil bulk density, enhance water retention capacity, influence soil pH and electrical conductivity, and escalate soil water evaporation. Exposure to MNPs may predominantly induce changes in soil microbial composition, reducing the diversity and complexity of microbial communities and microbial activity while enhancing soil organic carbon stability, influencing soil nutrient dynamics, and stimulating organic carbon decomposition and denitrification processes, leading to elevated soil respiration and methane emissions, and potentially decreasing soil nitrous oxide emission. Additionally, MNPs may adversely affect soil fauna, diminish seed germination rates, promote plant root growth, yet impair plant photosynthetic efficacy and biomass productivity. These findings contribute to a better understanding of the impacts and mechanistic foundations of MNPs. Future research avenues are suggested to further explore the impacts and economic implications.展开更多
Nanofibrous membrane has great advantages in many fields,of which the microstructural analysis and optimization are the key to the industrial application.The U-Net multiclassifier based on network structure together w...Nanofibrous membrane has great advantages in many fields,of which the microstructural analysis and optimization are the key to the industrial application.The U-Net multiclassifier based on network structure together with the Jaccard-Lovasz extension loss function was proposed to classify the pixels of the nanofiber SEM image into three categories.A Conditional Random Field(CRF)network was utilized to post-process the segmentation results.Porosities of the filter membranes and the radii of the nanofibers were calculated based on the segmentation results.Experimental results show that the proposed U-Net multiclassifier can be used to deal with overlapped nanofibers and the corresponding segmentation results can retain important details of the SEM image.The technique is beneficial to the subsequent numerical simulation,which is of great academic and practical significance for the subsequent film performance improvement and application promotion.展开更多
Multi-photon three-dimensional(3D)nanoprinting technology,renowned for its 3D processing capability and nano-scale resolution beyond the diffraction limit,has garnered significant attention in the micro/nano-additive ...Multi-photon three-dimensional(3D)nanoprinting technology,renowned for its 3D processing capability and nano-scale resolution beyond the diffraction limit,has garnered significant attention in the micro/nano-additive manufacturing field.This technology finds widespread applications in optics,biology,and mechanical engineering research.However,its broader adoption in industrial production and applications has been hindered by limitations such as relatively slow processing speed and restricted material formability and functionality.This paper presents the latest advancements in multi-photon 3D nanoprinting,with a focus on analyzing optical methods to enhance the processing speed of scanning and projection techniques.Additionally,it examines issues related to the formability and functionality of commonly used photosensitive materials,including organic polymers,inorganic compounds,and composite materials.In conclusion,this paper offers a comprehensive summary from the perspectives of productivity,cost,materials,and cross-scale processing,along with proposed routes and future directions.展开更多
The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was reviewed.The major goal is to highlight LiNixCoyMnzO2 materia...The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was reviewed.The major goal is to highlight LiNixCoyMnzO2 materials,which have been utilized in lithium ion batteries with enhanced energy and power density,high energy efficiency,superior rate capability and excellent cycling stability resulting from the doping,surface coating,nanocomposites and nano-architecturing.展开更多
In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The result...In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li＋ diffusion resistance and special structure of LFP/C microspheres.展开更多
Hierarchical dendritic micro–nano structure Zn Fe_2O_4 have been prepared by electrochemical reduction and thermal oxidation method in this work. X-ray diffractometry, Raman spectra and field-emission scanning electr...Hierarchical dendritic micro–nano structure Zn Fe_2O_4 have been prepared by electrochemical reduction and thermal oxidation method in this work. X-ray diffractometry, Raman spectra and field-emission scanning electron microscopy were used to characterize the crystal structure, size and morphology. The results show that the sample(S-2) is composed of pure ZnFe_2O_4 when the molar ratio of Zn^(2+)/Fe^(2+)in the electrolyte is 0.35. Decreasing the molar ratio of Zn^(2+)/Fe^(2+), the sample(S-1) is composed of ZnFe_2O_4 and α-Fe_2O_3, whereas increasing the molar ratio of Zn^(2+)/Fe^(2+), the sample(S-3) is composed of ZnFe_2O_4 and Zn O. The lattice parameters of ZnFe_2O_4 are influenced by the molar ratio of Zn^(2+)/Fe: Zn at excess decreases the cell volume whereas Fe at excess increases the cell volume of Zn Fe_2O_4. All the samples have the dendritic structure, of which S-2 has micron-sized lush branches with nano-sized leaves. UV–Vis diffuse reflectance spectra were acquired by a spectrophotometer. The absorption edges gradually blue shift with the increase of the molar ratio of Zn^(2+)/Fe^(2+). Photocatalytic activities for water splitting were investigated under Xe light irradiation in an aqueous olution containing 0.1 mol·L^(-1)Na_2S/0.02 mol·L^(-1)Na_2SO_3 in a glass reactor. The relatively highest photocatalytic activity with 1.41 μmol·h-1· 0.02 g^(-1)was achieved by pure ZnFe_2O_4sample(S-2). The photocatalytic activity of the mixture phase of Zn Fe_2O_4 and α-Fe_2O_3(S-1) is better than ZnF e_2O_4 and ZnO(S-3).展开更多
The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced ...The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.展开更多
Carbon fiber reinforced carbon composites(C/Cs),are the most promising high-temperature materials and could be widely applied in aerospace and nucleation fields,owing to their superior performances.However,C/Cs are ve...Carbon fiber reinforced carbon composites(C/Cs),are the most promising high-temperature materials and could be widely applied in aerospace and nucleation fields,owing to their superior performances.However,C/Cs are very susceptible to destructive oxidation and thus fail at elevated temperatures.Though matrix modification and coating technologies with Si-based and ultra-high temperature ceramics(UHTCs)are valid to enhance the oxidation/ablation resistance of C/Cs,it’s not sufficient to satisfy the increasing practical applications,due to the inherent brittleness of ceramics,mismatch issues between coatings and C/C substrates,and the fact that carbonaceous matrices are easily prone to high-temperature oxidation.To effectively solve the aforementioned problems,micro/nano multiscale reinforcing strategies have been developed for C/Cs and/or the coatings over the past two decades,to fabricate C/Cs with high strength and excellent high-temperature stability.This review is to systematically summarize the most recent major and important advancements in some micro/nano multiscale strategies,including nanoparticles,nanowires,carbon nanotubes/fibers,whiskers,graphene,ceramic fibers and hybrid micro/nano structures,for C/Cs and/or the coatings,to achieve high-temperature oxidation/ablation-resistant C/Cs.Finally,this review is concluded with an outlook of major unsolved problems,challenges to be met and future research advice for C/Cs with excellent comprehensive mechanical-thermal performance.It’s hoped that a better understanding of this review will be of high scientific and industrial interest,since it provides unusual and feasible new ideas to develop potential and practical C/Cs with improved high-temperature mechanical and oxidation/ablation-resistant properties.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.
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 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.
文摘The rapid evolution of laser micro/nano-manufacturing techniques has transformed precision manufacturing,enabling the creation of complex micro/nano-structures.These techniques are crucial for multiple industries,including electronics,photonics,and biomedical engineering,owing to their unmatched precision and versatility.The ability to manipulate materials at such scales has unlocked new possibilities for innovation,thereby facilitating the development of advanced components and devices with enhanced performance and functionalities.
基金supported by National Key R&D Program of China(Grant Nos.2021YFB2802000 and 2022YFB2804300)Science and Technology Commission of Shanghai Municipality(Grant No.21DZ1100500)+3 种基金Shanghai Municipal Science and Technology Major Projectthe Shanghai Frontiers Science Center Program(2021-2025 No.20)National Natural Science Foundation of China(Grant No.61975123)Shanghai Scienceand Technology Innovation Action Plan(Grant No.23JC1403100)。
文摘Able to precisely control and manipulate materials'states at micro/nano-scale level,femtosecond(fs)laser micro/nano processing technology has undergone tremendous development over the past three decades.Free-forming three-dimensional(3D)microscale functional devices and inducing fascinating and unique physical or chemical phenomena have granted this technology powerful versatility that no other technology can match.As this technology advances rapidly in various fields of application,some key challenges have emerged and remain to be urgently addressed.This review firstly introduces the fundamental principles for understanding how fs laser pulses interact with materials and the associated unique phenomena in section 2.Then micro/nano-fabrication in transparent materials by fs laser processing is presented in section 3.Thereafter,several high efficiency/throughput fabrication methods as well as pulse-shaping techniques are listed in sections 4 and 5 reviews four-dimensional(4D)and nanoscale printing realized by fs laser processing technology.Special attention is paid to the heterogeneous integration(HI)of functional materials enabled by fs laser processing in section 6.Several intriguing examples of 3D functional micro-devices created by fs laser-based manufacturing methods such as microfluidics,lab-on-chip,micro-optics,micro-mechanics,micro-electronics,micro-bots and micro-biodevices are reviewed in section 7.Finally,a summary of the review and a perspective are proposed to explore the challenges and future opportunities for further betterment of fs laser micro/nano processing technology.
基金The authors thank D.Berger,D.Hofmann and C.Kupka in IFW Dresden for helpful technical support.H.R.acknowledges funding from the DFG(Deutsche Forschungsgemeinschaft)within grant number RE3973/1-1.Q.J.,H.R.and K.N.conceived the work.With the support from N.Y.and X.J.,Q.J.and T.G.fabricated the thermoelectric films and conducted the structural and compositional characterizations.Q.J.prepared microchips and fabricated the on-chip micro temperature controllers.Q.J.and N.P.carried out the temperature-dependent material and device performance measurements.Q.J.and H.R.performed the simulation and analytical calculations.Q.J.,H.R.and K.N.wrote the manuscript with input from the other coauthors.All the authors discussed the results and commented on the manuscript.
文摘Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.
基金The work is supported in part by the National Natural Science Foundation of China(Grant Nos.62171483,82061148011)Zhejiang Provincial Natural Science Foundation of China(Grant No.LZ23F010004)+1 种基金Hangzhou Agricultural and Social Development Research Key Project(Grant No.20231203A08)Doctoral Initiation Program of the Tenth Affiliated Hospital,Southern Medical University(Grant No.K202308).
文摘The development of precise and sensitive electrophysiological recording platforms holds the utmost importance for research in the fields of cardiology and neuroscience.In recent years,active micro/nano-bioelectronic devices have undergone significant advancements,thereby facilitating the study of electrophysiology.The distinctive configuration and exceptional functionality of these active micro-nano-collaborative bioelectronic devices offer the potential for the recording of high-fidelity action potential signals on a large scale.In this paper,we review three-dimensional active nano-transistors and planar active micro-transistors in terms of their applications in electroexcitable cells,focusing on the evaluation of the effects of active micro/nano-bioelectronic devices on electrophysiological signals.Looking forward to the possibilities,challenges,and wide prospects of active micro-nano-devices,we expect to advance their progress to satisfy the demands of theoretical investigations and medical implementations within the domains of cardiology and neuroscience research.
基金the Fundamental Research Funds for the Central Universities(Grant No.30920041102)National Natural Science Foundation of China(Grant No.11802134).
文摘The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.
基金Supported financially by the National Natural Science Foundation of China(No.52102115)the High-end Foreign Expert Recruitment Plan of China(No.G2023036002L)+2 种基金the Natural Science Foundation of Sichuan Province,China(No.2023NSFSC0961)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06)the Postgraduate Innovation Fund Project by Southwest University of Science and Technology,China(No.24ycx2027).
文摘The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fiber(CF)plies to form thin interleaving,and various mass proportions of IT-MNASF were designed to discuss the reinforcing effect on the BCFRP heterogeneous composites.The results of three points bending tests showed that flexural strength and energy absorption of 4wt%IT-MNASF reinforced BCFRP heterogeneous composites had been improved by 32.4%and 134.4%respectively compared with that of unreinforced specimens.The 4wt%IT-MNASF reinforced BCFRP specimens showed both a greater strength and a lower cost(reduced by 31%around)than that of plain CFRP composites.X-ray micro-computed tomography scanning results exhibited that the delamination-dominated failure of plain BCFRP composites was changed into multi-layer BF and CF fabrics damage.The reinforcing mechanism revealed that the introduced IT-MNASF could construct quasi-vertical fiber bridging,and it was used as"mechanical claws"to grasp adjacent fiber layers for creating a stronger mechanical interlocking,and this effectively improved resin-rich region and interfacial transition region at the interlayers.The simple and effective IT-MNASF interleaving technique was very successful in low-cost and high-strength development of BCFRP heterogeneous composites.
基金supported financially by the National Natural Science Foundation of China(No.52102115)the High-end Foreign Expert Recruitment Plan of China(No.G2023036002L)+1 种基金the Basalt Fiber and Composite Key Laboratory of Sichuan Province,China(No.XXKFJJ202308)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06).
文摘The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transition region,and the flexible fiber bridging claws of MNSAF were constructed to grasp the adjacent layers for stronger interlaminar bond.The lowvelocity impact results show that the MNSAF could improve the impact resistance of BFRP composites.The compression test results demonstrate that the compressive strength and the residual compressive strength after impact of MNSAF-reinforced BFRP composites were greater than those of unreinforced one,exhibiting the greatest 56.2% and 73.3% increments respectively for BFRP composites improved by 4wt%MNSAF.X-ray micro-computed tomography scanning results indicate that the“fiber bridging claws”contributed to better mechanical interlocking to inhibit the crack generation and propagation under impact and compression load,and the original delamination-dominated failure of unreinforced BFRP composites was altered into sheardominated failure of MNSAF-reinforced BFRP composites.Overall,the MNSAF interleaving might be an effective method in manufacturing high-performance laminated fiber in industrial production.
文摘Micro- and nano-plastics (MNPs) are tiny plastic particles resulting from plastic product degradation. Soil MNPs have been identified as potential influential factors affecting various soil properties and crop biomass productivity. This mini-review provides a synthesis of recent findings concerning their effects on soil physicochemical properties, microorganisms, organic carbon content, soil nutrients, greenhouse gas emissions, soil fauna, and their impacts on plant ecophysiology, growth, and production. The results indicate that MNPs may markedly impede soil aggregation ability, increase porosity, decrease soil bulk density, enhance water retention capacity, influence soil pH and electrical conductivity, and escalate soil water evaporation. Exposure to MNPs may predominantly induce changes in soil microbial composition, reducing the diversity and complexity of microbial communities and microbial activity while enhancing soil organic carbon stability, influencing soil nutrient dynamics, and stimulating organic carbon decomposition and denitrification processes, leading to elevated soil respiration and methane emissions, and potentially decreasing soil nitrous oxide emission. Additionally, MNPs may adversely affect soil fauna, diminish seed germination rates, promote plant root growth, yet impair plant photosynthetic efficacy and biomass productivity. These findings contribute to a better understanding of the impacts and mechanistic foundations of MNPs. Future research avenues are suggested to further explore the impacts and economic implications.
基金supported by the National Natural Science Foundation of China (52275575)the Development and Reform Commission of Shenzhen Municipality (JSGG20220831094600002)Natural Science Foundation of Guangdong Province (2022A1515010923, 2022A1515010949)。
文摘Nanofibrous membrane has great advantages in many fields,of which the microstructural analysis and optimization are the key to the industrial application.The U-Net multiclassifier based on network structure together with the Jaccard-Lovasz extension loss function was proposed to classify the pixels of the nanofiber SEM image into three categories.A Conditional Random Field(CRF)network was utilized to post-process the segmentation results.Porosities of the filter membranes and the radii of the nanofibers were calculated based on the segmentation results.Experimental results show that the proposed U-Net multiclassifier can be used to deal with overlapped nanofibers and the corresponding segmentation results can retain important details of the SEM image.The technique is beneficial to the subsequent numerical simulation,which is of great academic and practical significance for the subsequent film performance improvement and application promotion.
基金financially supported by the National Key Research and Development Program of China(2021YFF0502700)the National Natural Science Foundation of China(52275429 and 62205117)+4 种基金the Innovation Project of Optics Valley Laboratory(OVL2021ZD002)the Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)the West Light Foundation of the Chinese Academy of Sciences(xbzg-zdsys-202206)the Knowledge Innovation Program of Wuhan-Shuguangthe Hubei Provincial Natu-ral Science Foundation of China(2022CFB792).
文摘Multi-photon three-dimensional(3D)nanoprinting technology,renowned for its 3D processing capability and nano-scale resolution beyond the diffraction limit,has garnered significant attention in the micro/nano-additive manufacturing field.This technology finds widespread applications in optics,biology,and mechanical engineering research.However,its broader adoption in industrial production and applications has been hindered by limitations such as relatively slow processing speed and restricted material formability and functionality.This paper presents the latest advancements in multi-photon 3D nanoprinting,with a focus on analyzing optical methods to enhance the processing speed of scanning and projection techniques.Additionally,it examines issues related to the formability and functionality of commonly used photosensitive materials,including organic polymers,inorganic compounds,and composite materials.In conclusion,this paper offers a comprehensive summary from the perspectives of productivity,cost,materials,and cross-scale processing,along with proposed routes and future directions.
基金Projects(51134007,21003161,21250110060) supported by the National Natural Science Foundation of ChinaProject(11MX10) supported by Central South University Annual Mittal-Founded Innovation ProjectProject(2011ssxt086) supported by Fundamental Research Funds for the Central Universities,China
文摘The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was reviewed.The major goal is to highlight LiNixCoyMnzO2 materials,which have been utilized in lithium ion batteries with enhanced energy and power density,high energy efficiency,superior rate capability and excellent cycling stability resulting from the doping,surface coating,nanocomposites and nano-architecturing.
基金Project(2013AA050901)supported by the National High-tech Research and Development Program of China
文摘In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li＋ diffusion resistance and special structure of LFP/C microspheres.
基金Supported by the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(2015DX07)
文摘Hierarchical dendritic micro–nano structure Zn Fe_2O_4 have been prepared by electrochemical reduction and thermal oxidation method in this work. X-ray diffractometry, Raman spectra and field-emission scanning electron microscopy were used to characterize the crystal structure, size and morphology. The results show that the sample(S-2) is composed of pure ZnFe_2O_4 when the molar ratio of Zn^(2+)/Fe^(2+)in the electrolyte is 0.35. Decreasing the molar ratio of Zn^(2+)/Fe^(2+), the sample(S-1) is composed of ZnFe_2O_4 and α-Fe_2O_3, whereas increasing the molar ratio of Zn^(2+)/Fe^(2+), the sample(S-3) is composed of ZnFe_2O_4 and Zn O. The lattice parameters of ZnFe_2O_4 are influenced by the molar ratio of Zn^(2+)/Fe: Zn at excess decreases the cell volume whereas Fe at excess increases the cell volume of Zn Fe_2O_4. All the samples have the dendritic structure, of which S-2 has micron-sized lush branches with nano-sized leaves. UV–Vis diffuse reflectance spectra were acquired by a spectrophotometer. The absorption edges gradually blue shift with the increase of the molar ratio of Zn^(2+)/Fe^(2+). Photocatalytic activities for water splitting were investigated under Xe light irradiation in an aqueous olution containing 0.1 mol·L^(-1)Na_2S/0.02 mol·L^(-1)Na_2SO_3 in a glass reactor. The relatively highest photocatalytic activity with 1.41 μmol·h-1· 0.02 g^(-1)was achieved by pure ZnFe_2O_4sample(S-2). The photocatalytic activity of the mixture phase of Zn Fe_2O_4 and α-Fe_2O_3(S-1) is better than ZnF e_2O_4 and ZnO(S-3).
基金supported by National Key Science and Technology Projects of China (Grant No. 2009ZX04001-101, Grant No. 2009ZX01001-151)New Century Excellent Talents in University,China (GrantNo. NCET-07-0246)National Natural Science Foundation of China(Grant No. 50675051)
文摘The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.
基金supported by the National Natural Science Foundation of China(Nos.91860203,51821091,51872239,52002321 and 52061135102)the China Postdoctoral Science Foundation(No.2019M660265)+3 种基金the Fundamental Research Funds for the Central Universities(China,Nos.G2019KY05116,G2020KY05125)the Innovation Talent Promotion Plan of Shaanxi Province for Science and Technology Innovation Team(No.2020TD003)the Creative Research Foundation of Science and Technology on Thermostructural Composite Materials Laboratory(Nos.614291102010517,5050200015 and 5150200033)the Shaanxi Provincial Education Department of China(No.2020JQ-170)。
文摘Carbon fiber reinforced carbon composites(C/Cs),are the most promising high-temperature materials and could be widely applied in aerospace and nucleation fields,owing to their superior performances.However,C/Cs are very susceptible to destructive oxidation and thus fail at elevated temperatures.Though matrix modification and coating technologies with Si-based and ultra-high temperature ceramics(UHTCs)are valid to enhance the oxidation/ablation resistance of C/Cs,it’s not sufficient to satisfy the increasing practical applications,due to the inherent brittleness of ceramics,mismatch issues between coatings and C/C substrates,and the fact that carbonaceous matrices are easily prone to high-temperature oxidation.To effectively solve the aforementioned problems,micro/nano multiscale reinforcing strategies have been developed for C/Cs and/or the coatings over the past two decades,to fabricate C/Cs with high strength and excellent high-temperature stability.This review is to systematically summarize the most recent major and important advancements in some micro/nano multiscale strategies,including nanoparticles,nanowires,carbon nanotubes/fibers,whiskers,graphene,ceramic fibers and hybrid micro/nano structures,for C/Cs and/or the coatings,to achieve high-temperature oxidation/ablation-resistant C/Cs.Finally,this review is concluded with an outlook of major unsolved problems,challenges to be met and future research advice for C/Cs with excellent comprehensive mechanical-thermal performance.It’s hoped that a better understanding of this review will be of high scientific and industrial interest,since it provides unusual and feasible new ideas to develop potential and practical C/Cs with improved high-temperature mechanical and oxidation/ablation-resistant properties.
