Recent progress on fabrication, spectroscopy properties, and device applications in Sn-doped CdS micro-nano structures

One-dimensional semiconductor materials possess excellent photoelectric properties and potential for the construction of integrated nanodevices. Among them, Sn-doped CdS has different micro-nano structures, including nanoribbons,nanowires, comb-like structures, and superlattices, with rich optical microcavity modes, excellent optical properties, and a wide range of application fields. This article reviews the research progress of various micrometer structures of Sn-doped CdS, systematically elaborates the effects of different growth conditions on the preparation of Sn-doped CdS micro-nano structures, as well as the spectral characteristics of these structures and their potential applications in certain fields. With the continuous progress of nanotechnology, it is expected that Sn-doped CdS micro-nano structures will achieve more breakthroughs in the field of optoelectronics and form cross-integration with other fields, jointly promoting scientific, technological, and social development.

Effect of brazing temperature on microstructure and tensile strength ofγ-TiAl joint vacuum brazed with micro-nano Ti−Cu−Ni−Nb−Al−Hf filler

A novel micro-nano Ti−10Cu−10Ni−8Al−8Nb−4Zr−1.5Hf filler was used to vacuum braze Ti−47Al−2Nb−2Cr−0.15B alloy at 1160−1220℃ for 30 min.The interfacial microstructure and formation mechanism of TiAl joints and the relationships among brazing temperature,interfacial microstructure and joint strength were emphatically investigated.Results show that the TiAl joints brazed at 1160 and 1180℃ possess three interfacial layers and mainly consist of α_(2)-Ti_(3)Al,τ_(3)-Al_(3)NiTi_(2) and Ti_(2)Ni,but the brazing seams are no longer layered and Ti_(2)Ni is completely replaced by the uniformly distributed τ_(3)-Al_(3)NiTi_(2) at 1200 and 1220℃ due to the destruction of α_(2)-Ti_(3)Al barrier layer.This transformation at 1200℃ obviously improves the tensile strength of the joint and obtains a maximum of 343 MPa.Notably,the outward diffusion of Al atoms from the dissolution of TiAl substrate dominates the microstructure evolution and tensile strength of the TiAl joint at different brazing temperatures.

Effect of Micro-electrolysis and Micro-nano Bubbles Coupled with Peroxymonosulfate Treatment of Rural Domestic Sewage

With the continuous deepening of rural revitalization strategy and the increasingly strict sewage discharge standards,rural domestic sewage treatment technology is facing higher challenges and requirements.The combined process of micro-electrolysis+micro-nano bubbles coupled with peroxymonosulfate was constructed in this study,and the treatment effect and application value of this technology were explored with the actual rural domestic sewage as the treatment object.The experimental results showed that under the conditions of HRT of 120 min,PMS dosage of 0.15 mmol/L,pH=7,MBs air intake of 15 ml/min,current intensity of 15 A,and Fe/C mass ratio of 1:1,the removal rates of COD,ammonia nitrogen and total phosphorus can reach 88.55%,77.18%and 74.67%,respectively.Under the condition that the pH value of sewage was not adjusted,the non-biochemical simultaneous decarbonization,denitrification and phosphorus removal of rural domestic sewage can be achieved by micro-electrolysis and micro-nano bubbles coupled with peroxymonosulfate.The concentrations of effluent COD,ammonia nitrogen and total phosphorus met the requirements of the first level standard of the Discharge Standard of Water Pollutants for Rural Domestic Sewage Treatment Facilities(DB45T2413-2021).And the comprehensive operating cost was about 1.15 yuan/m 3.

Synergistic Treatment of Low-concentration Organic Waste Gas by Micro-nano Bubble Coordinated with Peroxymonosulfate

Continuous dynamic experiment was conducted for the treatment of low-concentration organic waste gas with xylene as a representative, using micro-nano bubble and peroxymonosulfate working in synergy. The degradation rule of xylene under different conditions such as the ORP value of the spray liquid, pH value of the spray liquid, liquid-gas ratio of the spray liquid, residence time of xylene, and initial concentration of xylene was investigated. The results showed that at a low concentration, the pH value of the spray liquid had little effect on the degradation rate of xylene. The degradation rate of xylene rose with the increase of the ORP value of the spray liquid, the liquid-gas ratio of the spray liquid, the residence time of xylene, and the initial concentration of xylene.

Micro-nanostructural designs of bifunctional electrocatalysts for metal-air batteries

Water-based rechargeable metal-air batteries play an important role in the storage and conversion of renewable electric energy.However,the sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have limited the practical application of rechargeable metal-air batteries.Most of reviews were focused on single functional electrocatalysts while few on bifunctional electrocatalysts.It is indispensable but challenging to design a bifunctional electrocatalyst that is active and stable to the two reactions.Recently,attempts to develop high active bifunctional electrocatalysts for both ORR and OER increase rapidly.Much work is focused on the micro-nano design of advanced structures to improve the performance of bifunctional electrocatalyst.Transition-metal materials,carbon materials and composite materials,and the methods developed to prepare micro-nano structures,such as electrochemical methods,chemical vapor deposition,hydrothermal methods and template methods are reported in literatures.Additionally,many strategies,such as adjustments of electronic structures,oxygen defects,metal-oxygen bonds,interfacial strain,nano composites,heteroatom doping etc.,have been used extensively to design bifunctional electrocatalysts.To well understand the achievements in the recent literatures,this review focuses on the micro-nano structural design of materials,and the related methods and strategies are classed into two groups for the improvement of intrinsic and apparent activities.The fine adjustment of nano structures and an in-depth understanding of the reaction mechanism are also discussed briefly.

Adsorption of phenol from aqueous solution by a hierarchical micro-nano porous carbon material

A hierarchical micro-nano porous carbon material (MNC) was prepared using expanded graphite (EG), sucrose, and phosphoric acid as raw materials, followed by sucrose-phosphoric acid solution impregnation, solidification, carbonization and activation. Nitrogen adsorption and mercury porosimetry show that mixed nanopores and micropores coexist in MNC with a high specific surface area of 1978 m2·g-1 and a total pore volume of 0.99 cm3·g-1. In addition, the MNC is found to consist of EG and activated carbon with the latter deposited on the interior and the exterior surfaces of the EG pores. The thickness of the activated carbon layer is calculated to be about one hundred nanometers and is further confirmed by scanning electron microscope (SEM) and transmission election microscope (TEM). A maximum static phenol adsorption of 241.2 mg·g-1 was obtained by using MNC, slightly higher than that of 220.4 mg·g-1 by using commercial activated carbon (CAC). The phenol adsorption kinetics were investigated and the data fitted well to a pseudo-second-order model. Also, an intra-particle diffusion mechanism was proposed. Furthermore, it is found that the dynamic adsorption capacity of MNC is nearly three times that of CAC. The results suggest that the MNC is a more efficient adsorbent than CAC for the removal of phenol from aqueous solution.

Superamphiphobic, light-trapping FeSe2 particles with a micro-nano hierarchical structure obtained by an improved solvothermal method

Wettability and the light-trapping effect of FeSe2 particles with a micro-nano hierarchical structure have been inves- tigated. Particles are synthesized by an improved solvothermal method, wherein hexadecyl trimetbyl ammonium bromide （CTAB） is employed as a surfactant. After modifying the particles with heptadecafluorodecyltrimethoxy-silane （HTMS）, we find that the water contact angle （WCA） of the FeSe2 particles increases by 6.1~ and the water sliding angle （WSA） decreases by 2.5~ respectively, and the diffuse reflectivity decreases 29.4% compared with similar FeSe2 particles synthe- sized by the conventional method. The growth process of the particles is analyzed and a growth scenario is given. Upon altering the PH values of the water, we observe that the superhydrophobic property is maintained quite consistently across a wide PH range of 1-14. Moreover, the modified particles were also found to be superoleophobic. To the best of our knowledge, there is no systematic research on the wettability of FeSe2 particles, so our research provides a reference for other researchers.

Boosted Storage Kinetics in Thick Hierarchical Micro-Nano Carbon Architectures for High Areal Capacity Li-Ion Batteries

A practical and effective approach to increase the energy storage capacity of lithium ion batteries(LIBs)is to boost their areal capacity.Developing thick electrodes is one of the most crucial ways to achieve high areal capacity but limited by sluggish ion/electron transport,poor mechanical stability,and high-cost manufacturing strategies.Here we address these constraints by engineering a unique hierarchical-networked 10 mm thick all-carbon electrode,providing a scalable strategy to produce high areal capacity LIB electrodes.The hierarchical-networked structure utilizes micrometer-sized carbon fibers(MCFs)as building blocks,nano-sized carbon nanotubes(CNTs)as good continuous network with excellent electrical conductivity,and pyrolytic carbon as the binder and active material with excellent storage capacity.The combination of the above features endows our HNT-MCF/CNT/PC electrode with excellent performance including high reversible capacity of 15.44 mAh cm^(-2) at 2.0 mA cm^(-2) and exhibits excellent rate capability of 2.50 mAh cm^(-2) under 10.0 mA cm^(-2) current density.The Li-ion storage mechanism in HNT-MCF/CNT/PC involves dual-storage mechanism including intercalation and surface adsorption(pseudocapacitance)confirmed by the cyclic voltammetry and symmetric cell analysis.This work provides insights into the construction of high mechanical stability thick electrode for the next generation high areal capacity LIBs and beyond.

Investigation on Surface Plasmon Polaritons and Localized Surface Plasmon Production Mechanism in Micro-Nano Structures

The simulation mechanism of surface plasmon polaritons(SPPs)and localized surface plasmon(LSP)in different structures was studied,including the Au reflection grating(Au grating),Au substrate with dielectric ribbons grating(Au substrate grating),and pure electric conductor(PEC)substrate with Au ribbons grating(Au ribbons grating).And the characteristics of the Smith-Purcell radiation in these structures were presented.Simulation results show that SPPs are excited on the bottom surface of Au substrate grating grooves and LSP is stimulated on the upper surface both of Au ribbons grating grooves and Au grating grooves.Owing to the irreconcilable contradiction between optimizing the grating diffraction radiation efficiency and optimizing the SPPs excitation efficiency in the Au substrate grating,only 40-times enhancement of the radiation intensity was obtained by excited SPPs.However,the LSP enhanced structure overcomes the above problem and gains much better radiation enhancement ability,with about 200-times enhancement obtained in the Au ribbons grating and more than 500-times enhancement obtained in the Au grating.The results presented here provide a way of developing miniature,integratable,tunable,high-power-density radiation sources from visible light to ultraviolet rays at room temperature.

ZnO micro-nano composite hydrophobic film prepared by the three-step method

The hydrophobicity of the lotus leaf is mainly due to its surface micro-nano composite structure. In order to mimic the lotus structure, ZnO micro-nano composite hydrophobic films were prepared via the three-step method. On thin buffer films of SiO2, which were first fabricated on glass substrates by the so,gel dip-coating method, a ZnO seed layer was deposited via RF magnetron sputtering. Then two different ZnO films, micro-nano and micro-only flowerlike structures, were grown by the hydrothermal method. The prepared films have different hydrophobic properties after surface modification. The structures of the obtained ZnO films were characterized using x-ray diffraction and field-emission scanning electron microscopy. A conclusion that a micro-nano composite structure is more beneficial to hydrophobicity than a micro-only structure was obtained through research into the effect of structure on hydrophobic properties.

Preparation of micro-nano hollow multiphase ceramic microspheres containing MnFe_2O_4 absorbent by self-reactive quenching method

Fe–Fe2O3–MnO2–sucrose–epoxy resin and O2 as reaction system and feed gas,separately,were used to prepare micro-nano hollow multiphase ceramic microspheres containing MnFe2O4absorbent by self-reactive quenching method which is integrated with flame jet,selfpropagating high-temperature synthesis(SHS),and rapidly solidification.The morphologies and phase compositions of hollow microspheres were studied by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),and energy dispersive spectroscopy.The results show that the quenching products are regular spherical substantially with hollow structure,particle size is between few hundreds nanometers and 5 lm.Phase compositions are diphase of Fe3O4,Mn3O4,and MnFe2O4,and the spinel soft magnetic ferrite MnFe2O4 with microwave magnetic properties is in majority.Collisions with each other,burst as well as‘‘refinement’’of agglomerate powders in flame field may be the main reasons for the formation of micro-nano hollow multiphase ceramic microspheres containing MnFeOabsorbent.

Potential application of functional micro-nano structures in petroleum

This paper takes micro-nano motors and metamaterials as examples to introduce the basic concept and development of functional micro nano structures, and analyzes the application potential of the micro-nano structure design and manufacturing technology in the petroleum industry. The functional micro-nano structure is the structure and device with special functions prepared to achieve a specific goal. New functional micro-nano structures are classified into mobile type(e.g. micro-nano motors) and fixed type(e.g. metamaterials), and 3 D printing technology is a developed method of manufacturing. Combining the demand for exploration and development in oil and gas fields and the research status of intelligent micro-nano structures, we believe that there are 3 potential application directions:(1) The intelligent micro-nano structures represented by metamaterials and smart coatings can be applied to the oil recovery engineering technology and equipment to improve the stability and reliability of petroleum equipment.(2) The smart micro-nano robots represented by micro-motors and smart microspheres can be applied to the development of new materials for enhanced oil recovery, effectively improving the development efficiency of heavy oil, shale oil and other resources.(3) The intelligent structure manufacturing technology represented by 3 D printing technology can be applied to the field of microfluidics in reservoir fluids to guide the selection of mine flooding agents and improve the efficiency of mining.

Synthesis and electrochemical performance of micro-nano structured Li Fe1-xMnxPO4/C(0≤x≤0.05)cathode for lithium-ion batteries

Micro-nano structured Li Fe（1-x）MnxPO4/C（0≤x≤0.05）cathodes were prepared by spray drying,followed by calcination at 700°C.The spherical Li Fe（1-x）MnxPO4/C（0≤x≤0.05）particles with the size of 0.5 to5.0μm are composed of lots of nanoparticles of 20 to 30 nm,and have the well-developed interconnected pore structure.In contrast,when Mn doping content is 3 mol%（x=0.03）,the Li Fe（0.97）Mn（0.03）PO4/C demonstrates maximum specific surface area of 31.30 m^2/g,more uniform pore size and relatively better electrochemical performance.The initial discharge capacities are 161.59,157.04 and 153.13 m Ah/g at a discharge rate of 0.2,0.5 and 1 C,respectively.Meanwhile,the discharge capacity retentions are～100%after 120 cycles.The improved electrochemical performance should be attributed to higher specific surface,smaller polarization voltage,and a high Li~＋diffusion rate due to the micro-nano porous structure and lattice expansion produced by Mn doping.

Bibliometric analysis of micro-nano manufacturing technologies

Manufacturing is the primary industry promoting economic and social development.For the past 30 years,the global trends of preciseness and device miniaturisation have promoted manufacturing to the micro(μ)and nano(η)scale.Identification of themost promising micro-nano manufacturing technologies(MNMT)is of interest to industry,academia and private and national science investing foundations.Considering the exponential broadening of the research area and an enormous volume of literature,providing an overview of the state of the art is far beyond the scope of a technical review paper.This study performs bibliometric analysis of a stream of academic literature devoted toμ-andη-machining.Themain goals of the analysis are to assess the current core and trends in the field ofMNMT.Literature and citation statistics from 1988 were collected from theWeb of Science,Google Scholar,Scopus,Engineering Village,ScienceDirect and SpringerLink databases and were then analysed and illustrated with Microsoft Excel and VOSviewer software.The top keywords,articles,journals,authors,universities and countrieswere identified according to different parameters.The index of normalised influence was offered to evaluate the top element in each category.We observed that the most powerful keywords were present in well-known articles published in prominent journals by authoritative scientists at leading universities in the countries that are most actively engaged in MNMT.The implications of the research outcomes for investors and academicians are summarised in the conclusion.

Effect of Surface Roughness in Micro-nano Scale on Slotted Waveguide Arrays in Ku-band

Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and efficiency of the SWA in Ku-band. Firstly, the roughness is simulated using the electromechanical coupled（EC） model. The relationship between roughness and the antenna＇s radiation properties is obtained. For verification, an antenna proto- type is manufactured and tested, and the simulation method is introduced. According to the prototype, a contrasting experiment dealing with the flatness of the radiating plane is conducted to test the simulation method. The advantage of the EC model is validated by comparisons of the EC model and two classical roughness models （sine wave and fractal function）, which shows that the EC model gives a more accurate description model for roughness, the maxi- mum error is 13%. The existence of roughness strongly broadens the beamwidth and raises the side-lobe level of SWA, which is 1.2 times greater than the ideal antenna. In addition, effect of the EC model＇s evaluation indices is investigated, the most affected scale of the roughness is found, which is 1/10 of the working wavelength. The proposed research provides the instruction for antenna designing and manufacturing.

Chemically-induced active micro-nano bubbles assisting chemical mechanical polishing:Modeling and experiments

The material loss caused by bubble collapse during the micro-nano bubbles auxiliary chemical mechanical polishing(CMP)process cannot be ignored.In this study,the material removal mechanism of cavitation in the polishing process was investigated in detail.Based on the mixed lubrication or thin film lubrication,bubble-wafer plastic deformation,spherical indentation theory,Johnson-Cook(J-C)constitutive model,and the assumption of periodic distribution of pad asperities,a new model suitable for micro-nano bubble auxiliary material removal in CMP was developed.The model integrates many parameters,including the reactant concentration,wafer hardness,polishing pad roughness,strain hardening,strain rate,micro-jet radius,and bubble radius.The model reflects the influence of active bubbles on material removal.A new and simple chemical reaction method was used to form a controllable number of micro-nano bubbles during the polishing process to assist in polishing silicon oxide wafers.The experimental results show that micro-nano bubbles can greatly increase the material removal rate(MRR)by about 400%and result in a lower surface roughness of 0.17 nm.The experimental results are consistent with the established model.In the process of verifying the model,a better understanding of the material removal mechanism involved in micro-nano bubbles in CMP was obtained.

CoS_(2)/N,S co-doped mesoporous carbon with 3D micro-nano crosslinked structure as efficient bifunctional oxygen electrocatalysts for zinc-air batteries

This work describes a bifunctional oxygen catalyst made of cobalt disulfide encapsulated in N,S codoped mesoporous carbon with a novel three-dimensional micro-nano crosslinking structure.The proposed composite materials exhibit promising oxygen electrocatalytic activity and stability.The composite assembled rechargeable zinc-air battery can achieve a high power density of 208.9 m W/cm^(2),and can be stably cycled for more than 160 h.Additionally,the all-solid zinc-air battery assembled with the electrocatalyst also performs admirably.The micro-nano crosslinking and high porosity structure,as well as the large number of active sites generated by the synergy of N,S doping and the close interface between carbon matrix and CoS_(2),contribute to the composite's exceptional electrochemical performance.This study's rational strategy lays the path for the development of other high-performance bifunctional electrocatalysts.

Fibrous Separator with Surface Modification and Micro-Nano Fibers Lamination Enabling Fast Ion Transport for Lithium-Ion Batteries

Appropriate materials collaborated with reasonable structure can significantly increase the separator performance for lithium-ion batteries.In this work,taking the advantages of microfibrous and nanofibrous membranes and compensating for their defects,we developed a composited separator(GOPPH)with excellent overall performance by first wetting-modifying the polyethylene terephthalate microfibers and then laminating a polyvinylidene fluoride-hexafluoropropylene nanofiber layer.Such a combination not only offers the GOPPH separator,from the perspective of structure,with high porosity and hierarchical structure in terms of fiber diameter and pore size,but also provides satisfactory features including wettability,mechanical strength and thermal shutdown function that benefit from the selected materials.Meanwhile,as determined by experimental and theoretical approaches,the obtained GOPPH separator exhibits considerably enhanced lithium ion transport ability with a high lithium ion transference number and transport rate,which thereby endowing the cell with superior cycling stability with a capacity retention of 93%after 200 cycles at 1 C.Therefore,considering battery safety and performance,the GOPPH fibrous membrane could be a promising separator candidate for lithium-ion batteries.

Nanotopographic micro-nano forces finely tune the conformation of macrophage mechanosensitive membrane protein integrinβ_(2)to manipulate inflammatory responses

Finely tuning mechanosensitive membrane proteins holds great potential in precisely controlling inflammatory responses.In addition to macroscopic force,mechanosensitive membrane proteins are reported to be sensitive to micro-nano forces.Integrinβ_(2),for example,might undergo a piconewton scale stretching force in the activation state.High-aspect-ratio nanotopographic structures were found to generate nN-scale biomechanical force.Together with the advantages of uniform and precisely tunable structural parameters,it is fascinating to develop low-aspect-ratio nanotopographic structures to generate micro-nano forces for finely modulating their conformations and the subsequent mechanoimmiune responses.In this study,low-aspect-ratio nanotopographic structures were developed to finely manipulate the conformation of integrinβ_(2).The direct interaction of forces and the model molecule integrinαXβ_(2)was first performed.It was demonstrated that pressing force could successfully induce conformational compression and deactivation of integrinαXβ_(2),and approximately 270 to 720 pN may be required to inhibit its conformational extension and activation.Three low-aspect-ratio nanotopographic surfaces(nanohemispheres,nanorods,and nanoholes)with various structural parameters were specially designed to generate the micro-nano forces.It was found that the nanorods and nanohemispheres surfaces induce greater contact pressure at the contact interface between macrophages and nanotopographic structures,particularly after cell adhesion.These higher contact pressures successfully inhibited the conformational extension and activation of integrinβ_(2),suppressing focal adhesion activity and the downstream PI3K-Akt signaling pathway,reducing NF-κB signaling and macrophage inflammatory responses.Our findings suggest that nanotopographic structures can be used to finely tune mechanosensitive membrane protein conformation changes,providing an effective strategy for precisely modulating inflammatory responses.

Directionally tailoring micro-nano hierarchical tower structured Mn_(0.6)Ni_(1.4)Co_(2)O_(y) toward solar interfacial evaporation

Solar interfacial evaporation has been considered as a promising method to alleviate fresh water re-sources shortage.The shortage of freshwater resources requires advanced materials that can accelerate the evaporation of water by the sun.However,the simple structure of photothermal materials are vitally restricted by finite light absorption.Herein,this work presents a strategy for the synthesis of a spinel-type micro-nano hierarchical tower structure solar absorbent(Mn_(0.6)Ni_(1.4)Co_(2)O_(y))with the low forbidden band(=1.56 eV)and high absorption(97.88%).The products show great potential in solar-thermal energy conversion by creating a trapping effect.The prepared solar absorbent and epoxy resin are evenly mixed and then fully immersed in polyurethane(PU)sponge for water evaporation.The hydrophilic and porous Mn_(0.6)Ni_(1.4)Co_(2)O_(y)@PU sponge can quickly deliver water upwards,suppress the heat loss,and concentrate the absorbed heat on the evaporation of water.The products exhibited an excellent evaporation rate of 2.261 kg m^(-2) h^(-1) and an impressive evaporation efficiency of 156%under a single sun exposure.Besides,the samples also can maintain the stability and recycling performance for a long time.These findings show that Mn_(0.6)Ni_(1.4)Co_(2)O_(y) have great application prospects in the solar interfacial evaporation.