As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal...As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.展开更多
Surface passivation with organic ammoniums improves perovskite solar cell performance by forming 2D/quasi-2D structures or adsorbing onto surfaces.However,complexity from mixed phases can trigger phase transitions,com...Surface passivation with organic ammoniums improves perovskite solar cell performance by forming 2D/quasi-2D structures or adsorbing onto surfaces.However,complexity from mixed phases can trigger phase transitions,compromising stability.The control of surface dimensionality after organic ammonium passivation presents significant importance to device stability.In this study,we developed a poly-fluorination strategy for surface treatment in perovskite solar cells,which enabled a high and durable interfacial phase purity after surface passivation.The locked surface dimensionality of perovskite was achieved through robust interaction between the poly-fluorinated ammoniums and the perovskite surface,along with the steric hindrance imparted by fluorine atoms,reducing its reactivity and penetration capabilities.The high hydrophobicity of the poly-fluorinated surface also aids in moisture resistance of the perovskite layer.The champion device achieved a power conversion efficiency(PCE)of 25.2% with certified 24.6%,with 90% of its initial PCE retained after approximately 1200 h under continuous 1-sun illumination,and over 14,400 h storage stability and superior stability under high-temperature operation.展开更多
Based on the theoretical representation of piezoelectric quasicrystal,a generalized dynamic model is built to represent the transmission of wave aspects in surface acoustic pulse nano-devices.Surface elasticity,surfac...Based on the theoretical representation of piezoelectric quasicrystal,a generalized dynamic model is built to represent the transmission of wave aspects in surface acoustic pulse nano-devices.Surface elasticity,surface piezoelectricity,and surface permittivity help to include the surface effect,which equals additional thin sheets.It is shown that,under certain assumptions,this generalized dynamic model may be simplified to a few classical examples that are appropriate for both macro and nano-scale applications.In the current work,surface piezoelectricity is used to develop a theoretical model for shear horizontal(SH)waves where it contains the surface piezoelectricity theory and a linear spring model to quantitatively and qualitatively explore SH waves in an orthotropic piezoelectric quasicrystal layer overlying an elastic framework(Model I),a piezoelectric quasi-crystal nano substrate,and an orthotropic piezoelectric quasicrystal half-space(Model II).The theoretical model stimulates the numerical results,which establish the critical thickness.As the piezoelectric layer’s thickness gets closer to nanometres,surface energy must be included when analyzing dispersion properties.Furthermore,the effects of surface elasticity and density on wave velocity are investigated individually.The authors establish a parameter,precisely the ratio of the physical modulus along the width direction to along the direction of wave travel.The surface effect’s impact on the general char-acteristics of piezoelectric structures is seen as a spring force acting on bulk boundaries.Analytical presentation of frequency equations for both symmetric and anti-symmetric waves pertains to the case of an electrical short circuit in Model II.The project aims to analyze SH waves in orthogonal anisotropic,transversely isotropic piezoelectric layered nanostructures,providing a practical mathematical tool for surface effects analysis and adaptability to other wave types,including Rayleigh waves and acoustic surface waves.展开更多
Understanding frictional anisotropy,which refers to the variation in frictional resistance based on the shear direction,is crucial for optimizing the friction angle between a bio-inspired structure and the surrounding...Understanding frictional anisotropy,which refers to the variation in frictional resistance based on the shear direction,is crucial for optimizing the friction angle between a bio-inspired structure and the surrounding soil.Previous studies focused on estimating the interface frictional anisotropy mobilized by snakeskin-inspired textured surfaces and sand under monotonic shear loading conditions.However,there is a need to estimate interface frictional anisotropy under repetitive shear loads.In this study,a series of repetitive direct shear(DS)tests are performed with snakeskin-inspired textured surfaces under a constant vertical stress and two shear directions(cranial first half→caudal second half or caudal first half→cranial second half).The results show that(1)mobilized shear stress increases with the number of shearing cycles,(2)cranial shearing(shearing against the scales)consistently produces a higher shear resistance and less contractive behavior than caudal shearing(shearing along the scales),and(3)a higher scale height or smaller scale length of the surface yields a higher interface friction angle across all shearing cycles.Further analysis reveals that the gap between the cranial and caudal shear zones of the interface friction angle as a function of L/H(i.e.the ratio of scale length L to scale height H)continues to decrease as the number of shearing cycles approaches asymptotic values.The directional frictional resistance(DFR)decreases as the number of shearing cycles increases.Furthermore,the discussion covers the impact of initial relative density,vertical stress,and the number of shearing cycles on interface frictional anisotropy.展开更多
For emerging renewable and sustainable energy technologies,single crystal materials have become key materials to enhance electrocatalytic performance because of their atomic-level ordered structures and tailorable sur...For emerging renewable and sustainable energy technologies,single crystal materials have become key materials to enhance electrocatalytic performance because of their atomic-level ordered structures and tailorable surface and interfacial properties.Various single crystal types,including metals,semiconductors,ceramics,organics,and nanocrystals,exhibit superior catalytic selectivity and stability in reactions such as water splitting and carbon/nitrogen cycles,benefiting from high electrical conductivity,tunable energy bands,and active sites with high surface energy.Through surface modification,interfacial atomic doping,and heterostructure construction,the distribution of active sites,electronic structure,and mass transport can be precisely regulated,significantly optimizing the catalytic kinetics of single crystal materials.In situ characterizations elucidate catalytic mechanisms at the atomic scale,while emerging methods like AI-assisted synthesis and bio-template directed growth offer pathways to overcome bottlenecks in the precision and cost of single crystal preparation.In addressing stability challenges in complex environments,strategies such as organic-inorganic hybridization and gradient interface design effectively mitigate interfacial instability.Future research should focus on cross-scale structural regulation and multidisciplinary integration to facilitate the transition of single crystal electrocatalysts from fundamental research to industrial applications,enabling efficient energy conversion.展开更多
Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unex...Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unexplored.To address this gap,we designed a topological seismic metamaterial,where the topological interface is formed by joining the ends of two distinct one-dimensional periodic lattices.The first full-scale field experiment confirms the existence of topological interface states,which exhibit pronounced localization characteristics and induce a resonant amplification effect of 7.2 dB on the total energy of seismic surface waves.This study provides the first experimental validation for the implementation of topological principles in the design of seismic metamaterials,enabling novel approaches to high-sensitivity seismic detection and efficient energy localization for wave control.展开更多
Organic-inorganic hybrid metal halide perovskite solar cells(PSCs)have attracted much attention due to their high photoelectric conversion efficiency(PCE)and low cost.The certificated PCE of small active area(below 0....Organic-inorganic hybrid metal halide perovskite solar cells(PSCs)have attracted much attention due to their high photoelectric conversion efficiency(PCE)and low cost.The certificated PCE of small active area(below 0.1 cm^(2))device has reached 26.7%[1].However,when considering the scaled-up commercialization of PSCs,an obvious efficiency drop exists for the translation to large-area perovskite submodules(PSMs)with areas more than 200 cm^(2),thus limiting the practical commercialization[2].The major PCE gap between small area cells and large area modules arises the drop of open-circuit voltage(VOC)and fill factor(FF).Formamidinium lead iodide(FAPbI_(3))is now the mostly widely used and highly efficient perovskite composition.However,the photo-active black α-FAPbI_(3) phase will spontaneously transform into photo-inactive yellowδ-FAPbI_(3) phase at room temperature[3].展开更多
An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as t...An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as the amplitude of the liquid column oscillations increases,parametric oscillations of the interface are excited in the form of a standing wave located in the channel plane.In particular,depending on the interfacial tension,the standing waves have a frequency equal to that of liquid piston oscillations(harmonic response),or half of the frequency of oscillations of the liquid column in the channel(subharmonic response).The detected type of instability has a gravitational-capillary nature and is analogous to Faraday waves.The analysis of the overcritical dynamics of wave oscillations indicates that interfacial tension plays a crucial role in determining the type of parametric instability.At high interfacial tension,only synchronous(harmonic)wave modes are observed,and the threshold of the wave excitation is determined by the amplitude of piston oscillations of the liquid column.In this case,the oscillation acceleration does not play a role and has a small value in the threshold of the synchronous mode response.In the case of weak surface tension,subharmonic oscillations are observed.The threshold for the development of these oscillations is determined by the dimensionless acceleration of the oscillating liquid column and remains almost constant with variations in the dimensionless frequency of oscillations.At moderate values of interfacial tension(in the region of moderate dimensionless frequencies),a synchronous wave mode emerges in the stability threshold of the oscillating interface.As the dimensionless acceleration is increased further,a subharmonic mode is excited.The growth of subharmonic oscillations occurs against the background of harmonic wave oscillations,with the oscillations of the interface representing a combination of two standing waves.展开更多
In this paper,we consider the plasma-vacuum interface problem in a cylindrical tube region impressed by a special background magnetic field.The interior region is occupied with plasma,which is governed by the incompre...In this paper,we consider the plasma-vacuum interface problem in a cylindrical tube region impressed by a special background magnetic field.The interior region is occupied with plasma,which is governed by the incompressible inviscid and resistive MHD system without damping term.The exterior vacuum region is governed by the so-called the“pre-Maxwell equations”.And on the free interface,additionally,the effect of surface tension is taken into account.The original region can be transformed into a horizontally periodic slab through the cylindrical coordinate transformation,which will be impressed by a uniform nonhorizontal magnetic field.Appending with the appropriate physical boundary conditions,the global well-posedness of the problem is established by the energy method.展开更多
Ground response analysis and determination of site-specific ground motion parameters are necessary for evaluating seismic loads to enable sustainable design of aboveground and underground structures,particularly in de...Ground response analysis and determination of site-specific ground motion parameters are necessary for evaluating seismic loads to enable sustainable design of aboveground and underground structures,particularly in deep overburden sites.This study investigates the influence of bedrock interface conditions and depth of soil deposits on obtained site-specific ground motion parameters.Employing the one-dimensional seismic response analysis program SOILQUAKE,the ground responses of five representative soil profiles and 1050 case studies are calculated considering three different site models of seismic input interfaces.The analysis employs the actual bedrock interface with a shear wave velocity of 760 m/s as the reference input bedrock interface.The results illustrate that the selection of the bedrock interface condition significantly affects the seismic response on the ground surface of deep overburden sites.Specifically,the ground surface acceleration response spectra at longer periods are notably smaller compared to those at the actual bedrock site.This may present a challenge for designing long-period high-rise buildings situated in deep overburden sites.It is recommended to select a seismic input bedrock interface closely approximating the actual bedrock depth when conducting seismic response analyses for deep overburden sites.展开更多
The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface...The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface transfer doping,surface electron acceptor materials with high electron affinity(EA)are required to produce a high density of two-dimensional hole gas(2DHG)on the H-diamond subsurface.We have established ingenious theoretical models to demonstrate that even if these solid materials do not have a high EA value,they remain capable of absorbing electrons from the H-diamond surface by forming a negatively charged interface to act as a surface electron acceptor in the surface transfer doping model.Our calculations,particularly for the local density of states,provide compelling evidence that the effect of an interface with negative charges induces an upward band bending on the H-diamond side.Furthermore,the valence band maximum of the diamond atoms at the interface crosses the Fermi level,giving rise to strong surface transfer p-type doping.These results give a strong theoretical interpretation of the origin of 2DHG on H-diamond surfaces.The proposed guidelines contribute to further improvements in the performance of 2DHG H-diamond field effect transistors.展开更多
Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affecte...Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affected by the built-in electric field of the heterostructure.In this study,P/N co-doped carbon-coated NiCo/Ni-CoO heterostructure was prepared by in situ acid etching,aniline polymerization,and pyrolysis.This method can form a tightly connected heterogeneous interface.It was found that introducing P-O bonds in the carbon shell can increase its work function,thereby enhancing the built-in electric field between the carbon shell and the core catalyst.Detailed characterizations confirm that the P-O bridge at the heterogeneous interface can provide an electron flow highway from the core to the shell.The generated carbon defects generated by P leaching during surface reconstruction also have strong electronabsorbing capacity.These effects promote the conversion of Co^(2+)to Co^(3+),thereby providing more highly active sites.The resulting catalyst shows significantly enhanced activity and stability.This study demonstrates the promoting effect of the built-in electric field on the surface reconstruction of the catalyst and emphasizes the importance of the construction of tightly connected heterogeneous interface,which is instructive for the design of excellent OER catalysts.展开更多
Transition metal selenides(TMSs)are effective pre-electrocatalysts and are commonly used in electrochemical processes.During the electrocatalytic oxygen evolution reaction(OER),metal cations in TMSs are in-situ recons...Transition metal selenides(TMSs)are effective pre-electrocatalysts and are commonly used in electrochemical processes.During the electrocatalytic oxygen evolution reaction(OER),metal cations in TMSs are in-situ reconstructed and converted into high-valence metal oxyhydroxides.However,a limited understanding of the effects of electro-oxidation and anion leaching has resulted in insufficient theoretical guidance for the rational design of efficient catalysts.Herein,FeSe@NiSe nanorods were fabricated for the OER using a facile hydrothermal selenization method supported on FeNi foam.In-situ Raman spectroscopy and multiple characterization techniques were employed to elucidate the mechanism of FeSe@NiSe surface evolution.Metal cations on the catalyst surface were reconstructed and converted into OER-active species Fe/NiOOH at low potential.As the applied potential increased,electro-oxidation and leaching of Se occurred,resulting in SeO_(4)^(2−)adsorption on the catalyst surface,which further enhanced catalytic activity.As a result,the reconstructed FeSe@NiSe/iron-nickel foam(INF)exhibited exceptional catalytic activity for OER,achieving an ultralow overpotential of 283 mV at a current density of 100 mA·cm^(−2).Notably,the bifunctional FeSe@NiSe/INF electrode facilitated overall water splitting,affording a current density of 10 mA·cm^(−2) only at 1.53 V,even superior to the noble RuO_(2)(+)||Pt/C(−).This work offers valuable insights into the surface evolution and electrocatalytic mechanisms of TMSs.展开更多
Silicon carbide(SiC)is a highly valued material for power semiconductor devices due to its wide bandgap,high thermal conductivity,and high breakdown electric field.However,its high hardness,brittleness,and chemical st...Silicon carbide(SiC)is a highly valued material for power semiconductor devices due to its wide bandgap,high thermal conductivity,and high breakdown electric field.However,its high hardness,brittleness,and chemical stability present substantial challenges for efficient and high-quality processing.This study investigated the effects of picosecond laser surface scanning on 4H-SiC to enhance the material removal performance.The research focused on surface morphology,phase transitions,subsurface/interface characteristics,and material removal mechanisms under varying laser parameters.The results demonstrate that the laser thermal effect decomposes 4H-SiC into amorphous silicon(a-Si),disordered carbon,and graphite,forming a resolidified layer containing Si-O and Si-C-O oxides.Crystalline silicon(c-Si)is produced under high fluences or extensive irradiations.The variation in the resolidified layer thickness with changing laser parameters is revealed.A detailed laser-induced subsurface damage model is developed,encompassing a resolidified layer that includes the above decomposition and oxidation products,and a deformed layer formed primarily under laser-induced stress.The presence of the resolidified layer and the deformed layer leads to a decreased elastic recovery rate and an increased scratching depth,exceeding 2.5 times that of the unmodified condition.Enhanced material removal performance is mainly driven by the resolidified layer at low fluence and by the deformed layer at high fluence.When aligning the total of the ablation depth and the resolidified layer thickness with the subsurface damage depth in the original material,excellent polishing performance is achieved.These findings provide critical insights for understanding the phase evolution,subsurface damage mechanisms,and material removal behavior of 4H-SiC,offering valuable guidance for optimizing the laser surface modification parameters to achieve high-efficiency processing.展开更多
Lithium-carbon dioxide(Li-CO_(2))batteries with high theoretical energy density are regarded as promising energy storage system toward carbon neutrality.However,bidirectional catalysts design for improving the sluggis...Lithium-carbon dioxide(Li-CO_(2))batteries with high theoretical energy density are regarded as promising energy storage system toward carbon neutrality.However,bidirectional catalysts design for improving the sluggish CO_(2)reduction reaction(CO_(2)RR)/CO_(2)evolution reaction(CO_(2)ER)kinetics remains a huge challenge.In this work,an advanced catalyst with fast-interfacial charge transfer was subtly synthesized through element segregation,which significantly improves the electrocatalytic activity for both CO_(2)RR and CO_(2)ER.Theoretical calculations and characterization analysis demonstrate local charge redistribution at the constructed interface,which leads to optimized binding affinity towards reactants and preferred Li_(2)CO_(3)decomposition behavior,enabling excellent catalytic activity during CO_(2)redox.Benefiting from the enhanced charge transfer ability,the designed highly efficient catalyst with dual active centers and large exposed catalytic area can maintain an ultra-small voltage gap of 0.33 V and high energy efficiency of 90.2%.This work provides an attractive strategy to construct robust catalysts by interface engineering,which could inspire further design of superior bidirectional catalysts for Li-CO_(2)batteries.展开更多
An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow...An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow engineering the microstructures for desired properties through smartly designing fabrication processing parameters.This is demonstrated for SnO2 nano-particle surfaces and also a technologically important Ag-SnO2 interface fabricated by in-situ internal oxidation.Based on defect thermodynamics,we first modeled and calculated the equilibrium surface and interface structures,and as well corresponding properties,as a function of the ambient temperature and oxygen partial pressure.A series of first principles energetics calculations were then performed to construct the equilibrium surface and interface phase diagrams,to describe the environment dependence of the microstructures and properties of the surfaces and interfaces during fabrication and service conditions.The use and potential application of these phase diagrams as a process design tool were suggested and discussed.展开更多
A CuPc/SiO2 sample is fabricated. Its morphology is characterized by atomic force microscopy, and the electron states are investigated by X-ray photoelectron spectroscopy. In order to investigate these spectra in deta...A CuPc/SiO2 sample is fabricated. Its morphology is characterized by atomic force microscopy, and the electron states are investigated by X-ray photoelectron spectroscopy. In order to investigate these spectra in detail, all of these spectra are normalized to the height of the most intense peak,and each component is fitted with a single Gaussian function. Analysis shows that the O element has great bearing on the electron states and that SiO2 layers produced by spurting technology are better than those produced by oxidation technology.展开更多
Hydrogen peroxide(H_(2)O_(2))oxidation and reduction reactions(HPOR/HPRR)are pivotal in various innovative electrochemical energy conversion devices.A comprehensive understanding of these mechanisms is critical for ca...Hydrogen peroxide(H_(2)O_(2))oxidation and reduction reactions(HPOR/HPRR)are pivotal in various innovative electrochemical energy conversion devices.A comprehensive understanding of these mechanisms is critical for catalyst design and performance improvement in these applications.In this work,we systematically investigate the HPOR/HPRR mechanisms on low-index Pt surfaces,specifically Pt(111),Pt(100)and Pt(110),through density functional theory(DFT)calculations combined with the computational hydrogen electrode(CHE)model.For HPOR,all the low-index Pt surfaces exhibit a unified potential-determining step(PDS)involving the electrochemical oxidation of hydroperoxyl intermediates(HOO*).The binding free energy of HOO*(Δ_(GHOO*))emerges as an activity descriptor,with Pt(110)exhibiting the highest HPOR activity.The HPRR mechanism follows a chem-electrochemical(C-EC)pathway.The rate-determining step(RDS)of HPRR is either the cleavage of the HO-OH bond(chemical)or the reduction of HO(electrochemical),depending on their respective activation energies.These activation energies are functions of the HO*binding free energy,Δ_(GHO*),establishingΔ_(GHO*)as the descriptor for HPRR activity prediction.Pt(111)and Pt(100)are identified as the most active HPRR catalysts among the studied metal surfaces,although they still experience a significant overpotential.The scaling relationship betweenΔ_(GHOO*)andΔ_(GHO*)reveals a thermodynamic coupling of HPOR and HPRR,explaining their occurrence on Pt surfaces.These findings provide important insights and activity descriptors for both HPOR and HPRR,providing valuable guidance for the design of electrocatalysts in H_(2)O_(2)-related energy applications and fuel cells.展开更多
Invasive as well as non-invasive neurotechnologies conceptualized to interface the central and peripheral nervous system have been probed for the past decades,which refer to electroencephalography,electrocorticography...Invasive as well as non-invasive neurotechnologies conceptualized to interface the central and peripheral nervous system have been probed for the past decades,which refer to electroencephalography,electrocorticography and microelectrode arrays.The challenges of these mentioned approaches are characterized by the bandwidth of the spatiotemporal resolution,which in turn is essential for large-area neuron recordings(Abiri et al.,2019).展开更多
High-performance alloys are indispensable in modern engineering because of their exceptional strength,ductility,corrosion resistance,fatigue resistance,and thermal stability,which are all significantly influenced by t...High-performance alloys are indispensable in modern engineering because of their exceptional strength,ductility,corrosion resistance,fatigue resistance,and thermal stability,which are all significantly influenced by the alloy interface structures.Despite substantial efforts,a comprehensive overview of interface engineering of high-performance alloys has not been presented so far.In this study,the interfaces in high-performance alloys,particularly grain and phase boundaries,were systematically examined,with emphasis on their crystallographic characteristics and chemical element segregations.The effects of the interfaces on the electrical conductivity,mechanical strength,toughness,hydrogen embrittlement resistance,and thermal stability of the alloys were elucidated.Moreover,correlations among various types of interfaces and advanced experimental and computational techniques were examined using big data analytics,enabling robust design strategies.Challenges currently faced in the field of interface engineering and emerging opportunities in the field are also discussed.The study results would guide the development of next-generation high-performance alloys.展开更多
基金financially supported by the National Key R&D Program of China(No.2022YFE0121300)the National Natural Science Foundation of China(No.52374376)the Introduction Plan for High-end Foreign Experts(No.G2023105001L)。
文摘As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.
基金grants(grant numbers LR24F040001,LD24E020001 and LD22E020002)from the Natural Science Foundation of Zhejiang Province of Chinathe National Natural Science Foundation of China(grant number 62274146)+1 种基金the support of Key R&D Program of Zhejiang(2024SSYS0061)supported by the Fundamental Research Funds for the Central Universities(226-2022-00200).
文摘Surface passivation with organic ammoniums improves perovskite solar cell performance by forming 2D/quasi-2D structures or adsorbing onto surfaces.However,complexity from mixed phases can trigger phase transitions,compromising stability.The control of surface dimensionality after organic ammonium passivation presents significant importance to device stability.In this study,we developed a poly-fluorination strategy for surface treatment in perovskite solar cells,which enabled a high and durable interfacial phase purity after surface passivation.The locked surface dimensionality of perovskite was achieved through robust interaction between the poly-fluorinated ammoniums and the perovskite surface,along with the steric hindrance imparted by fluorine atoms,reducing its reactivity and penetration capabilities.The high hydrophobicity of the poly-fluorinated surface also aids in moisture resistance of the perovskite layer.The champion device achieved a power conversion efficiency(PCE)of 25.2% with certified 24.6%,with 90% of its initial PCE retained after approximately 1200 h under continuous 1-sun illumination,and over 14,400 h storage stability and superior stability under high-temperature operation.
文摘Based on the theoretical representation of piezoelectric quasicrystal,a generalized dynamic model is built to represent the transmission of wave aspects in surface acoustic pulse nano-devices.Surface elasticity,surface piezoelectricity,and surface permittivity help to include the surface effect,which equals additional thin sheets.It is shown that,under certain assumptions,this generalized dynamic model may be simplified to a few classical examples that are appropriate for both macro and nano-scale applications.In the current work,surface piezoelectricity is used to develop a theoretical model for shear horizontal(SH)waves where it contains the surface piezoelectricity theory and a linear spring model to quantitatively and qualitatively explore SH waves in an orthotropic piezoelectric quasicrystal layer overlying an elastic framework(Model I),a piezoelectric quasi-crystal nano substrate,and an orthotropic piezoelectric quasicrystal half-space(Model II).The theoretical model stimulates the numerical results,which establish the critical thickness.As the piezoelectric layer’s thickness gets closer to nanometres,surface energy must be included when analyzing dispersion properties.Furthermore,the effects of surface elasticity and density on wave velocity are investigated individually.The authors establish a parameter,precisely the ratio of the physical modulus along the width direction to along the direction of wave travel.The surface effect’s impact on the general char-acteristics of piezoelectric structures is seen as a spring force acting on bulk boundaries.Analytical presentation of frequency equations for both symmetric and anti-symmetric waves pertains to the case of an electrical short circuit in Model II.The project aims to analyze SH waves in orthogonal anisotropic,transversely isotropic piezoelectric layered nanostructures,providing a practical mathematical tool for surface effects analysis and adaptability to other wave types,including Rayleigh waves and acoustic surface waves.
基金the funding supported from the National Research Foundation of Korea(NRF)grant funded by the Korea Government MSIT(No.2021R1C1C1006003).
文摘Understanding frictional anisotropy,which refers to the variation in frictional resistance based on the shear direction,is crucial for optimizing the friction angle between a bio-inspired structure and the surrounding soil.Previous studies focused on estimating the interface frictional anisotropy mobilized by snakeskin-inspired textured surfaces and sand under monotonic shear loading conditions.However,there is a need to estimate interface frictional anisotropy under repetitive shear loads.In this study,a series of repetitive direct shear(DS)tests are performed with snakeskin-inspired textured surfaces under a constant vertical stress and two shear directions(cranial first half→caudal second half or caudal first half→cranial second half).The results show that(1)mobilized shear stress increases with the number of shearing cycles,(2)cranial shearing(shearing against the scales)consistently produces a higher shear resistance and less contractive behavior than caudal shearing(shearing along the scales),and(3)a higher scale height or smaller scale length of the surface yields a higher interface friction angle across all shearing cycles.Further analysis reveals that the gap between the cranial and caudal shear zones of the interface friction angle as a function of L/H(i.e.the ratio of scale length L to scale height H)continues to decrease as the number of shearing cycles approaches asymptotic values.The directional frictional resistance(DFR)decreases as the number of shearing cycles increases.Furthermore,the discussion covers the impact of initial relative density,vertical stress,and the number of shearing cycles on interface frictional anisotropy.
基金supported by National Natural Science Foundation of China(No.52202366)Taishan Scholar Project of Shandong Province(tstp20240515,tsqn202312217)+1 种基金Natural Science Foundation of Shandong Province(China,No.2025HWYQ-050,ZR2021QE011,ZR2022QH072,ZR2021QE284)the King Abdullah University of Science and Technology,the Center of Excellence for Renewable Energy and Storage Technologies.
文摘For emerging renewable and sustainable energy technologies,single crystal materials have become key materials to enhance electrocatalytic performance because of their atomic-level ordered structures and tailorable surface and interfacial properties.Various single crystal types,including metals,semiconductors,ceramics,organics,and nanocrystals,exhibit superior catalytic selectivity and stability in reactions such as water splitting and carbon/nitrogen cycles,benefiting from high electrical conductivity,tunable energy bands,and active sites with high surface energy.Through surface modification,interfacial atomic doping,and heterostructure construction,the distribution of active sites,electronic structure,and mass transport can be precisely regulated,significantly optimizing the catalytic kinetics of single crystal materials.In situ characterizations elucidate catalytic mechanisms at the atomic scale,while emerging methods like AI-assisted synthesis and bio-template directed growth offer pathways to overcome bottlenecks in the precision and cost of single crystal preparation.In addressing stability challenges in complex environments,strategies such as organic-inorganic hybridization and gradient interface design effectively mitigate interfacial instability.Future research should focus on cross-scale structural regulation and multidisciplinary integration to facilitate the transition of single crystal electrocatalysts from fundamental research to industrial applications,enabling efficient energy conversion.
基金supported by the National Natural Science Foundation of China(Grant No.11974044)。
文摘Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unexplored.To address this gap,we designed a topological seismic metamaterial,where the topological interface is formed by joining the ends of two distinct one-dimensional periodic lattices.The first full-scale field experiment confirms the existence of topological interface states,which exhibit pronounced localization characteristics and induce a resonant amplification effect of 7.2 dB on the total energy of seismic surface waves.This study provides the first experimental validation for the implementation of topological principles in the design of seismic metamaterials,enabling novel approaches to high-sensitivity seismic detection and efficient energy localization for wave control.
基金support from open fund of Fujian Provincial Key Laboratory of Functional Materials and Applications(Xiamen University of Technology,fma2024003)the National Key R&D Program of China(No.2021YFB3500400)the National Natural Science Foundation of China(Nos.52073286 and 22275185).
文摘Organic-inorganic hybrid metal halide perovskite solar cells(PSCs)have attracted much attention due to their high photoelectric conversion efficiency(PCE)and low cost.The certificated PCE of small active area(below 0.1 cm^(2))device has reached 26.7%[1].However,when considering the scaled-up commercialization of PSCs,an obvious efficiency drop exists for the translation to large-area perovskite submodules(PSMs)with areas more than 200 cm^(2),thus limiting the practical commercialization[2].The major PCE gap between small area cells and large area modules arises the drop of open-circuit voltage(VOC)and fill factor(FF).Formamidinium lead iodide(FAPbI_(3))is now the mostly widely used and highly efficient perovskite composition.However,the photo-active black α-FAPbI_(3) phase will spontaneously transform into photo-inactive yellowδ-FAPbI_(3) phase at room temperature[3].
基金supported by the Ministry of Education of the Russian Federation(Project No.1023032300071-6-2.3.1).
文摘An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as the amplitude of the liquid column oscillations increases,parametric oscillations of the interface are excited in the form of a standing wave located in the channel plane.In particular,depending on the interfacial tension,the standing waves have a frequency equal to that of liquid piston oscillations(harmonic response),or half of the frequency of oscillations of the liquid column in the channel(subharmonic response).The detected type of instability has a gravitational-capillary nature and is analogous to Faraday waves.The analysis of the overcritical dynamics of wave oscillations indicates that interfacial tension plays a crucial role in determining the type of parametric instability.At high interfacial tension,only synchronous(harmonic)wave modes are observed,and the threshold of the wave excitation is determined by the amplitude of piston oscillations of the liquid column.In this case,the oscillation acceleration does not play a role and has a small value in the threshold of the synchronous mode response.In the case of weak surface tension,subharmonic oscillations are observed.The threshold for the development of these oscillations is determined by the dimensionless acceleration of the oscillating liquid column and remains almost constant with variations in the dimensionless frequency of oscillations.At moderate values of interfacial tension(in the region of moderate dimensionless frequencies),a synchronous wave mode emerges in the stability threshold of the oscillating interface.As the dimensionless acceleration is increased further,a subharmonic mode is excited.The growth of subharmonic oscillations occurs against the background of harmonic wave oscillations,with the oscillations of the interface representing a combination of two standing waves.
基金supported by the NSFC(11571177)the National Key Research and Development Program of China(2020YFA0713803).
文摘In this paper,we consider the plasma-vacuum interface problem in a cylindrical tube region impressed by a special background magnetic field.The interior region is occupied with plasma,which is governed by the incompressible inviscid and resistive MHD system without damping term.The exterior vacuum region is governed by the so-called the“pre-Maxwell equations”.And on the free interface,additionally,the effect of surface tension is taken into account.The original region can be transformed into a horizontally periodic slab through the cylindrical coordinate transformation,which will be impressed by a uniform nonhorizontal magnetic field.Appending with the appropriate physical boundary conditions,the global well-posedness of the problem is established by the energy method.
基金supported by the National Natural Science Foundation of China(Nos.52408435,52278384)。
文摘Ground response analysis and determination of site-specific ground motion parameters are necessary for evaluating seismic loads to enable sustainable design of aboveground and underground structures,particularly in deep overburden sites.This study investigates the influence of bedrock interface conditions and depth of soil deposits on obtained site-specific ground motion parameters.Employing the one-dimensional seismic response analysis program SOILQUAKE,the ground responses of five representative soil profiles and 1050 case studies are calculated considering three different site models of seismic input interfaces.The analysis employs the actual bedrock interface with a shear wave velocity of 760 m/s as the reference input bedrock interface.The results illustrate that the selection of the bedrock interface condition significantly affects the seismic response on the ground surface of deep overburden sites.Specifically,the ground surface acceleration response spectra at longer periods are notably smaller compared to those at the actual bedrock site.This may present a challenge for designing long-period high-rise buildings situated in deep overburden sites.It is recommended to select a seismic input bedrock interface closely approximating the actual bedrock depth when conducting seismic response analyses for deep overburden sites.
基金supported by the National Nat-ural Science Foundation of China(Nos.62174122,U2241244,and 52302046)Major Program(JD)of Hubei Province(No.2023BAA008)+2 种基金the Fundamental Research Funds for the Central Universities(Nos.2042023kf0116 and 2042023kf1041)the Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515011764 and 2024A1515010383)the Open Fund of Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration(Wuhan University)(No.EMPI2023016).
文摘The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface transfer doping,surface electron acceptor materials with high electron affinity(EA)are required to produce a high density of two-dimensional hole gas(2DHG)on the H-diamond subsurface.We have established ingenious theoretical models to demonstrate that even if these solid materials do not have a high EA value,they remain capable of absorbing electrons from the H-diamond surface by forming a negatively charged interface to act as a surface electron acceptor in the surface transfer doping model.Our calculations,particularly for the local density of states,provide compelling evidence that the effect of an interface with negative charges induces an upward band bending on the H-diamond side.Furthermore,the valence band maximum of the diamond atoms at the interface crosses the Fermi level,giving rise to strong surface transfer p-type doping.These results give a strong theoretical interpretation of the origin of 2DHG on H-diamond surfaces.The proposed guidelines contribute to further improvements in the performance of 2DHG H-diamond field effect transistors.
基金financially supported by the National Natural Science Foundation of China(Grant No.52073106)。
文摘Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affected by the built-in electric field of the heterostructure.In this study,P/N co-doped carbon-coated NiCo/Ni-CoO heterostructure was prepared by in situ acid etching,aniline polymerization,and pyrolysis.This method can form a tightly connected heterogeneous interface.It was found that introducing P-O bonds in the carbon shell can increase its work function,thereby enhancing the built-in electric field between the carbon shell and the core catalyst.Detailed characterizations confirm that the P-O bridge at the heterogeneous interface can provide an electron flow highway from the core to the shell.The generated carbon defects generated by P leaching during surface reconstruction also have strong electronabsorbing capacity.These effects promote the conversion of Co^(2+)to Co^(3+),thereby providing more highly active sites.The resulting catalyst shows significantly enhanced activity and stability.This study demonstrates the promoting effect of the built-in electric field on the surface reconstruction of the catalyst and emphasizes the importance of the construction of tightly connected heterogeneous interface,which is instructive for the design of excellent OER catalysts.
基金supported by the National Natural Science Foundation of China(No.22469018)the Natural Science Basic Research Program of Department of Science and Technology of Shaanxi Province(Nos.2023-JC-ZD-22 and 2023-JC-YB-404)the Scientific Research Startup Program for Introduced Talents of Shaanxi University of Technology(Nos.SLGRCQD2303 and SLGRCQD2306).
文摘Transition metal selenides(TMSs)are effective pre-electrocatalysts and are commonly used in electrochemical processes.During the electrocatalytic oxygen evolution reaction(OER),metal cations in TMSs are in-situ reconstructed and converted into high-valence metal oxyhydroxides.However,a limited understanding of the effects of electro-oxidation and anion leaching has resulted in insufficient theoretical guidance for the rational design of efficient catalysts.Herein,FeSe@NiSe nanorods were fabricated for the OER using a facile hydrothermal selenization method supported on FeNi foam.In-situ Raman spectroscopy and multiple characterization techniques were employed to elucidate the mechanism of FeSe@NiSe surface evolution.Metal cations on the catalyst surface were reconstructed and converted into OER-active species Fe/NiOOH at low potential.As the applied potential increased,electro-oxidation and leaching of Se occurred,resulting in SeO_(4)^(2−)adsorption on the catalyst surface,which further enhanced catalytic activity.As a result,the reconstructed FeSe@NiSe/iron-nickel foam(INF)exhibited exceptional catalytic activity for OER,achieving an ultralow overpotential of 283 mV at a current density of 100 mA·cm^(−2).Notably,the bifunctional FeSe@NiSe/INF electrode facilitated overall water splitting,affording a current density of 10 mA·cm^(−2) only at 1.53 V,even superior to the noble RuO_(2)(+)||Pt/C(−).This work offers valuable insights into the surface evolution and electrocatalytic mechanisms of TMSs.
基金supported by the research studentship of The Hong Kong Polytechnic University(Project code:RMAN)the Research and Innovation Office of The Hong Kong Polytechnic University(Project codes:1-W308 and 1-BECE)+2 种基金the Research Grants Council of the Government of the Hong Kong Special Administrative Region(HKSAR),China(No.15205423)funding support from the Innovation and Technology Commission(ITC)of HKSAR,China(MHP/151/22)funding support from the State Key Laboratory of Ultra-precision Machining Technology(Project code:BBX5).
文摘Silicon carbide(SiC)is a highly valued material for power semiconductor devices due to its wide bandgap,high thermal conductivity,and high breakdown electric field.However,its high hardness,brittleness,and chemical stability present substantial challenges for efficient and high-quality processing.This study investigated the effects of picosecond laser surface scanning on 4H-SiC to enhance the material removal performance.The research focused on surface morphology,phase transitions,subsurface/interface characteristics,and material removal mechanisms under varying laser parameters.The results demonstrate that the laser thermal effect decomposes 4H-SiC into amorphous silicon(a-Si),disordered carbon,and graphite,forming a resolidified layer containing Si-O and Si-C-O oxides.Crystalline silicon(c-Si)is produced under high fluences or extensive irradiations.The variation in the resolidified layer thickness with changing laser parameters is revealed.A detailed laser-induced subsurface damage model is developed,encompassing a resolidified layer that includes the above decomposition and oxidation products,and a deformed layer formed primarily under laser-induced stress.The presence of the resolidified layer and the deformed layer leads to a decreased elastic recovery rate and an increased scratching depth,exceeding 2.5 times that of the unmodified condition.Enhanced material removal performance is mainly driven by the resolidified layer at low fluence and by the deformed layer at high fluence.When aligning the total of the ablation depth and the resolidified layer thickness with the subsurface damage depth in the original material,excellent polishing performance is achieved.These findings provide critical insights for understanding the phase evolution,subsurface damage mechanisms,and material removal behavior of 4H-SiC,offering valuable guidance for optimizing the laser surface modification parameters to achieve high-efficiency processing.
基金supported by the National Key Research and Development Program of China(2019YFA0705700)Guangdong Innovative and Entrepreneurial Research Team Program(2021ZT09L197)+2 种基金Shenzhen Science and Technology Program(KQTD20210811090112002)Interdisciplinary Research and Innovation Fund of Tsinghua Shenzhen International Graduate School,National Natural Science Foundation of China(No.52373233)the SIAT International Joint Lab Project(No.E3G113).
文摘Lithium-carbon dioxide(Li-CO_(2))batteries with high theoretical energy density are regarded as promising energy storage system toward carbon neutrality.However,bidirectional catalysts design for improving the sluggish CO_(2)reduction reaction(CO_(2)RR)/CO_(2)evolution reaction(CO_(2)ER)kinetics remains a huge challenge.In this work,an advanced catalyst with fast-interfacial charge transfer was subtly synthesized through element segregation,which significantly improves the electrocatalytic activity for both CO_(2)RR and CO_(2)ER.Theoretical calculations and characterization analysis demonstrate local charge redistribution at the constructed interface,which leads to optimized binding affinity towards reactants and preferred Li_(2)CO_(3)decomposition behavior,enabling excellent catalytic activity during CO_(2)redox.Benefiting from the enhanced charge transfer ability,the designed highly efficient catalyst with dual active centers and large exposed catalytic area can maintain an ultra-small voltage gap of 0.33 V and high energy efficiency of 90.2%.This work provides an attractive strategy to construct robust catalysts by interface engineering,which could inspire further design of superior bidirectional catalysts for Li-CO_(2)batteries.
基金Project(51171211) supported by the National Natural Science Foundation of ChinaProject(NCET-10-0837) supported by the Chinese Ministry of Education's Supportive Program for New Century Excellent Talents in UniversitiesProject(2006BAE03B03) supported by the Chinese National Science and Technology Supportive Program
文摘An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow engineering the microstructures for desired properties through smartly designing fabrication processing parameters.This is demonstrated for SnO2 nano-particle surfaces and also a technologically important Ag-SnO2 interface fabricated by in-situ internal oxidation.Based on defect thermodynamics,we first modeled and calculated the equilibrium surface and interface structures,and as well corresponding properties,as a function of the ambient temperature and oxygen partial pressure.A series of first principles energetics calculations were then performed to construct the equilibrium surface and interface phase diagrams,to describe the environment dependence of the microstructures and properties of the surfaces and interfaces during fabrication and service conditions.The use and potential application of these phase diagrams as a process design tool were suggested and discussed.
文摘A CuPc/SiO2 sample is fabricated. Its morphology is characterized by atomic force microscopy, and the electron states are investigated by X-ray photoelectron spectroscopy. In order to investigate these spectra in detail, all of these spectra are normalized to the height of the most intense peak,and each component is fitted with a single Gaussian function. Analysis shows that the O element has great bearing on the electron states and that SiO2 layers produced by spurting technology are better than those produced by oxidation technology.
基金Supported by the Shanxi Province Grant(202203021212007,2023SHB003).
文摘Hydrogen peroxide(H_(2)O_(2))oxidation and reduction reactions(HPOR/HPRR)are pivotal in various innovative electrochemical energy conversion devices.A comprehensive understanding of these mechanisms is critical for catalyst design and performance improvement in these applications.In this work,we systematically investigate the HPOR/HPRR mechanisms on low-index Pt surfaces,specifically Pt(111),Pt(100)and Pt(110),through density functional theory(DFT)calculations combined with the computational hydrogen electrode(CHE)model.For HPOR,all the low-index Pt surfaces exhibit a unified potential-determining step(PDS)involving the electrochemical oxidation of hydroperoxyl intermediates(HOO*).The binding free energy of HOO*(Δ_(GHOO*))emerges as an activity descriptor,with Pt(110)exhibiting the highest HPOR activity.The HPRR mechanism follows a chem-electrochemical(C-EC)pathway.The rate-determining step(RDS)of HPRR is either the cleavage of the HO-OH bond(chemical)or the reduction of HO(electrochemical),depending on their respective activation energies.These activation energies are functions of the HO*binding free energy,Δ_(GHO*),establishingΔ_(GHO*)as the descriptor for HPRR activity prediction.Pt(111)and Pt(100)are identified as the most active HPRR catalysts among the studied metal surfaces,although they still experience a significant overpotential.The scaling relationship betweenΔ_(GHOO*)andΔ_(GHO*)reveals a thermodynamic coupling of HPOR and HPRR,explaining their occurrence on Pt surfaces.These findings provide important insights and activity descriptors for both HPOR and HPRR,providing valuable guidance for the design of electrocatalysts in H_(2)O_(2)-related energy applications and fuel cells.
文摘Invasive as well as non-invasive neurotechnologies conceptualized to interface the central and peripheral nervous system have been probed for the past decades,which refer to electroencephalography,electrocorticography and microelectrode arrays.The challenges of these mentioned approaches are characterized by the bandwidth of the spatiotemporal resolution,which in turn is essential for large-area neuron recordings(Abiri et al.,2019).
基金supported by the National Natural Science Foundation of China(Nos.52122408 and 52474397)the High-level Talent Research Start-up Project Funding of Henan Academy of Sciences(No.242017127)+1 种基金the financial support from the Fundamental Research Funds for the Central Universities(University of Science and Technology Beijing(USTB),Nos.FRF-TP-2021-04C1 and 06500135)supported by USTB MatCom of Beijing Advanced Innovation Center for Materials Genome Engineering。
文摘High-performance alloys are indispensable in modern engineering because of their exceptional strength,ductility,corrosion resistance,fatigue resistance,and thermal stability,which are all significantly influenced by the alloy interface structures.Despite substantial efforts,a comprehensive overview of interface engineering of high-performance alloys has not been presented so far.In this study,the interfaces in high-performance alloys,particularly grain and phase boundaries,were systematically examined,with emphasis on their crystallographic characteristics and chemical element segregations.The effects of the interfaces on the electrical conductivity,mechanical strength,toughness,hydrogen embrittlement resistance,and thermal stability of the alloys were elucidated.Moreover,correlations among various types of interfaces and advanced experimental and computational techniques were examined using big data analytics,enabling robust design strategies.Challenges currently faced in the field of interface engineering and emerging opportunities in the field are also discussed.The study results would guide the development of next-generation high-performance alloys.
