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.

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.

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.

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.

Mechanical Simulation of Hierarchical Micro-Nano Structure of Butterfly Wings

The ridge-cross rib microstructures of Carystoides escalantei butterfly wing scales have been reproduced by 2D and 3D models via the ANSYS software,and the structural analyses under tensile and bending deformation,as well as the relative failure analyses are performed for those models.It has been found that the curved model in which the ridges acted as triangular prisms while the cross-ribs acted as bend cuboids could simulate the real scale configuration more accurately.Besides,it also shows much more even stress distribution under deformation and better mechanical properties than the rectangular one,in which both ridges and cross-ribs are modeled as regular cuboids.

Advanced Functional Electromagnetic Shielding Materials:A Review Based on Micro‑Nano Structure Interface Control of Biomass Cell Walls

Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.

Viscosity and structure relationship with equimolar substitution of CaO with MgO in the CaO–MgO–Al_(2)O_(3)–SiO_(2)slag melts

Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this limitation.Unlike most studies that concentrated on managing the MgO/Al_(2)O_(3)ratio or basicity,this paper explored the effect of equimolar substitution of MgO for CaO on the viscosity and structure of a high-alumina CaO-MgO-Al_(2)O_(3)-SiO_(2)slag system,providing theoretical guidance and data to facilitate the application of high-alumina ores.The results revealed that the viscosity first decreased and then increased with higher MgO substitution,reaching a minimum at 15mol%MgO concentration.Fourier transform infrared spectroscopy(FTIR)results found that the depths of the troughs representing[SiO_(4)]tetrahedra,[AlO_(4)]tetrahedra,and Si-O-Al bending became progressively deeper with increased MgO substitution.Deconvolution of the Raman spectra showed that the average number of bridging oxygens per Si atom and the X_(Q^(3))/X_(Q^(2))(X_(Q^(i))is the molar fraction of Q^(i) unit,and i is the number of bridging oxygens in a[SiO_(4)]tetrahedral unit)ratio increased from 2.30 and 1.02 to 2.52 and 2.14,respectively,indicating a progressive polymerization of the silicate structure.X-ray photoelectron spectroscopy(XPS)results highlighted that non-bridging oxygen content decreased from 77.97mol% to 63.41mol% with increasing MgO concentration,whereas bridging oxygen and free oxygen contents increased.Structural analysis demonstrated a gradual increase in the polymerization degree of the tetrahedral structure with the increase in MgO substitution.However,bond strength is another important factor affecting the slag viscosity.The occurrence of a viscosity minimum can be attributed to the complex evolution of bond strengths of non-bridging oxygens generated during depolymerization of the[SiO_(4)]and[AlO_(4)]tetrahedral structures by CaO and MgO.

Emerging structures and dynamic mechanisms ofγ-secretase for Alzheimer’s disease

γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface receptors.Mutations inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well.However,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-secretase.In this review,we focus on recent studies of structural dynamic mechanisms ofγ-secretase.Different mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics simulations.While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental findings.The approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-secretase.In addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is discussed.Finally,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations of theγ-secretase-substrate complexes.Comprehensive understanding of the functional mechanisms ofγ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general.

Designing Electronic Structures of Multiscale Helical Converters for Tailored Ultrabroad Electromagnetic Absorption

Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.

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.

Micro-nano structured functional coatings deposited by liquid plasma spraying

Inspired by the micro-nano structure on the surface of biological materials or living organisms,micro-nano structure has been widely investigated in the field of functional coatings.Due to its large specific surface area,porosity,and dual-scale structure,it has recently attracted special attention.The typical fabrication processes of micro-nano structured coatings include sol-gel,hydrothermal synthesis,chemical vapor deposition,etc.This paper presents the main features of a recent deposition and synthesis technique,liquid plasma spraying(LPS).LPS is an important technical improvement of atmospheric plasma spraying.Compared with atmospheric plasma spraying,LPS is more suitable for preparing functional coatings with micro-nano structure.Micro-nano structured coatings are mainly classified into hierarchical-structure and binary-structure.The present study reviews the preparation technology,structural characteristics,functional properties,and potential applications of LPS coatings with a micro-nano structure.The micro-nano structured coatings obtained through tailoring the structure will present excellent performances.

Flexible Triboelectric Nanogenerator from Micro-nano Structured Polydimethylsiloxane

Triboelectric nanogenerator（TENG） can convert mechanical energy to electrical energy through contact electrification and electrostatic induction. Single-friction-surface triboelectric nanogenerator（STENG） extends poten- tial application because a finger can be used as one friction surface in the contact electrification. In this work, a fully flexible STENG has been made, consisting of polydimethylsiloxane（PDMS） with micro-nano structures on its ob- serve side and a flexible electrode on its reverse side. The femtosecond laser ablation was introduced to make micro-nano structures on PDMS and Ag nanowires（Ag NWs） were embedded in PDMS to serve as flexible induction electrode. It has been demonstrated that the energy conversion efficiency increases greatly because of the existing micro-nano structures on PDMS. Further, the mechanism of STENG was proved. Owing to the fully flexible charac- teristics in both the electrode and PDMS, STENG works well when it is adhered on any subject, for example, on clothes by tape.

Osteogenic and antibacterial ability of micro-nano structures coated with ZnO on Ti-6Al-4V implant fabricated by two-step laser processing

The biological performance of Ti-6Al-4V implant is primarily determined by their surface properties.However,traditional surface modification methods,such as acid etching,hardly make improvement in their osseointegration ability and antibacterial capacity.In this study,we prepared a multi-scale composite structure coated with zinc oxide(ZnO)on Ti-6Al-4V implant by an innovative technology of two-step laser processing combined with solution-assistant.Compared with the acid etching method,the physicochemical properties of surface significantly improved.The in vitro results showed that the particular dimension of micro-nano structure and the multifaceted nature of ZnO synergistically affected MC3T3-E1 osteogenesis and bacterial activities:(1)The surface morphology showed a‘contact guidance'effect on cell arrangement,which was conducive to the adhesion of filopodia and cell spreading,and the osteogenesis level of MC3T3-E1 was enhanced due to the release of zinc ions(Zn^(2+));(2)the characterization of bacterial response revealed that periodic nanostructures and Zn^(2+)released could cause damage to the cell wall of E.coli and reduce the adhesion and aggregation of S.aureus.In conclusion,the modified surface showed a synergistic effect of physical topography and chemical composition,making this a promising method and providing new insight into bone defect repairment.

Micro-nano structured VNb_(9)O_(25)anode with superior electronic conductivity for high-rate and long-life lithium storage

The oxygen vacancies and micro-nano structure can optimize the electron/Li+migration kinetics in anode materials for lithium batteries(LIBs).Here,porous micro-nano structured VNb_(9)O_(25)composites with rich oxygen vacancies were reasonably prepared via a facile solvothermal method combined with annealing treatment at 800℃for 30 h(VNb_(9)O_(25)-30 h).This micro-nano structure can enhance the contact of active material/electrolyte,and shorten the Li+diffusion distance.The introduction of oxygen vacancies can further boosts the intrinsic conductivity of VNb_(9)O_(25)-30 h for achieving excellent LIB performance.The as-prepared VNb_(9)O_(25)-30 h anode showed advanced rate capability with reversible capacity of 122.2 m A h g^(-1)at 4 A g^(-1),and delivered excellent capacity retention of~100%after 2000 cycles.Meanwhile,VNb_(9)O_(25)-30 h provides unexpected long-cycle life(i.e.,reversible capacity of 165.7 m A h g^(-1)at 1 A g^(-1)with a high capacity retention of 85.6%even after 8000 cycles).Additionally,coupled with the Li Fe PO4 cathode,the Li Fe PO4//VNb_(9)O_(25)-30 h full cell delivers superior LIB properties with high reversible capacities of 91.6 m A h g^(-1)at 5 C for 1000 cycles.Thus,such reasonable construction method can assist in other high-performance niobium-based oxides in LIBs.

Surface Micro-Nano Structures on GaN Thin Films Induced by 355 nm Nanosecond Laser Irradiation

Gallium nitride(GaN)has widespread applications in the semiconductor industry because of its desirable optoelectronic properties.The fabrication of surface structures on GaN thin films can effectively modify their optical and electrical properties,providing additional degrees of freedom for controlling GaN-based devices.Compared with lithography-based techniques,laser processing is maskless and much more efficient.This paper shows how surface micronano structures can be produced on GaN thin films using 355 nm nanosecond laser irradiation.The effects of the laser pulse energy,number of pulses,and polarization direction were studied.It was found that distinct micro-nano structures were formed under different irradiation conditions,and their geometries and elemental compositions were analyzed.The results indicate that different types of surface micro-nano structures can be produced on GaN thin films in a controllable manner using 355 nm nanosecond laser irradiation.The results of our study provide valuable guidance for the surface modification of GaN-based optoelectronic devices.

Carbon Emission Effects Driven by Evolution of Chinese Dietary Structure from 1987 to 2020

Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important task.This study took China as the research object(data excluding Hong Kong,Macao and Taiwan) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary structure.The results showed that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption pattern.The dietary structure of urban residents developed to a balanced one,while that of rural residents developed to a high-quality one.During the study period,the per capita food carbon emissions and total food consumption of Chinese showed an increasing trend.The per capita food carbon emissions of residents in urban and rural showed an overall upward trend.The total food carbon emissions in urban increased significantly,while that in rural increased first and then decreased.The influence of beef and mutton on carbon emissions is the highest in dietary structure.Compared with the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but were evolving to a high-carbon consumption pattern.

Seismic response of a mid-story isolated structure considering SSI in mountainous areas under long-period earthquakes

At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is established along with a model that does not consider SSI.Eight long-period earthquake waves and two ordinary earthquake waves are selected as inputs for the dynamic time history analysis of the structure.The results show that the seismic response of a mid-story isolated structure considering SSI in mountainous areas can be amplified when compared with a structure that does not consider SSI.The structure response under long-period earthquakes is larger than that of ordinary earthquakes.The structure response under far-field harmonic-like earthquakes is larger than that of near-fault pulse-type earthquakes.The structure response under near-fault pulse-type earthquakes is larger than that of far-field non-harmonic earthquakes.When subjected to long-period earthquakes,the displacement of the isolated bearings exceeded the limit value,which led to instability and overturning of the structure.The structure with dampers in the isolated story could adequately control the nonlinear response of the structure,effectively reduce the displacement of the isolated bearings,and provide a convenient,efficient and economic method not only for new construction but also to retrofit existing structures.

OptoGPT: A foundation model for inverse design in optical multilayer thin film structures

Optical multilayer thin film structures have been widely used in numerous photonic applications.However,existing inverse design methods have many drawbacks because they either fail to quickly adapt to different design targets,or are difficult to suit for different types of structures,e.g.,designing for different materials at each layer.These methods also cannot accommodate versatile design situations under different angles and polarizations.In addition,how to benefit practical fabrications and manufacturing has not been extensively considered yet.In this work,we introduce OptoGPT(Opto Generative Pretrained Transformer),a decoder-only transformer,to solve all these drawbacks and issues simultaneously.

A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods:antioxidant and bile acid-binding capacity

In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

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.