Aluminum-air batteries(AABs)are considered the most promising candidates in advanced clean energy conversion and storage due to their low density,high specific energy,and abundant aluminum resources;however,the develo...Aluminum-air batteries(AABs)are considered the most promising candidates in advanced clean energy conversion and storage due to their low density,high specific energy,and abundant aluminum resources;however,the development of AABs is constrained by inevitable parasitic side reactions and anodic surface passivation film formation.The present work introduced an innovative hybrid corrosion inhibitor consisting of potassium stannate,decyl glucoside,and 1,10-decanedithiol to regulate solid-liquid interface reactions in alkaline AABs.The findings indicated that the optimal hybrid corrosion inhibitor could reduce the hydrogen evolution rate from 0.2095 to 0.0406 mL cm^(-2)min^(-1),achieving an inhibition efficiency of 80.62%.The surface analysis discussed in detail the evolution process of the solid-liquid interface after the introduction of the hybrid corrosion inhibitor into the battery.Experiments and theoretical calculations revealed that decyl glucoside enhanced the adsorption and coverage efficiency of the hybrid corrosion inhibitor through the“micelle solubilization”effect and optimized the structure and properties of the solid-liquid interface.This study also contributed valuable insights into the corrosion inhibition mechanism at the solid-liquid interface of alkaline AABs.展开更多
Whether the particle will be trapped by the solid-liquid interface or not is dependent on its moving behavior ahead of the interface, so a mathematical model has been developed to investigate the movement of the parti...Whether the particle will be trapped by the solid-liquid interface or not is dependent on its moving behavior ahead of the interface, so a mathematical model has been developed to investigate the movement of the particle ahead of the solid-liquid interface. Based on the theory for the boundary layer, the fluid velocity field near the solid-liquid interface was obtained, and the trajectories of particles were calculated by the equations of motion for particles. In this model, the drag force, the added mass force, the buoyance force, the gravitational force, the Saffman force and the Basset history force are considered. The results show that the behavior of the particle ahead of the solid-liquid interface is affected by the physical property of the particle and fluid flow. And in the continuous casting process, if it moves in the stream directed upward or downward near vertical solid-liquid interface or in the horizontal flow under the solid-liquid interface, the particle with the diameter from 5 um to 60um can reach the solid-liquid interface. But if it moves in horizontal flow above the solid-liquid interface, only the particle with the diameter from 5 um to 10 um can reach the solid-liquid interface.展开更多
Self-assembly of nanoparticles at solid-liquid interface could be promising to realize the assembled functions for various applications,such as rechargeable batteries,supercapacitors,and electrocatalysis.This review s...Self-assembly of nanoparticles at solid-liquid interface could be promising to realize the assembled functions for various applications,such as rechargeable batteries,supercapacitors,and electrocatalysis.This review summarizes the self-assembly of the nanoparticles at solid-liquid interface according to the different driving forces of assembly,including hydrophilic-hydrophobic interactions,solvophobic and electrostatic interaction.To be specific,the self-assembly can be divided into the following two types:surfactant-assisted self-assembly and direct self-assembly of Janus particles(inorganic and amphiphilic copolymer-inorganic Janus nanoparticles).Using the emulsion stabilized by nanoparticles as the template,the self-assembly constructed by the interaction of the nanostructure unit(including metal,metal oxide,and semiconductor,etc.)not only possesses the characteristic of nanostructure unit,but also exhibits the excellent assembly performance in electrochemistry aspect.The application of these assemblies in the area of electrochemical capacitors is presented.Finally,the current research progress and perspectives toward the self-assembly of nanoparticles at stabilized solid-liquid interface are proposed.展开更多
The solidification microstructure and fractal characteristics of the solid-liquid interfaces of Inconel 718,under different cooling rates during directional solidification,were investigated by using SEM. Results showe...The solidification microstructure and fractal characteristics of the solid-liquid interfaces of Inconel 718,under different cooling rates during directional solidification,were investigated by using SEM. Results showed that 5 μm/s was the cellular-dendrite transient rate. The prime dendrite arm spacing (PDAS) was measured by Image Tool and it decreased with the cooling rate increased. The fractal dimension of the interfaces was calculated and it changes from 1.204310 to 1.517265 with the withdrawal rate ranging from 10 to 100 μm/s. The physical significance of the fractal dimension was analyzed by using fractal theory. It was found that the fractal dimension of the dendrites can be used to describe the solidification microstructure and parameters at low cooling rate,but both the fractal dimension and the dendrite arm spacing are needed in order to integrally describe the evaluation of the solidification microstructure completely.展开更多
The paper presents a new relationship between the three surface tensions on the solid-liquid-vapor interface, γ_(sl)-γ_(sv)+γ_(lv)cosθ=βin order to understand the wetting on the liquid-solid interface in the case...The paper presents a new relationship between the three surface tensions on the solid-liquid-vapor interface, γ_(sl)-γ_(sv)+γ_(lv)cosθ=βin order to understand the wetting on the liquid-solid interface in the case of active adsorption.The authors suggest a new force“apparent active adsorption force”βto take part in the balance at the three interface lines of contact in the solid-liquid-vapor phases,its dimen- sion isβ=Σα_iRT(Γ_i^(sl)-Γ_i^(sv)+Γ_i^(lv)cosθ),and its direction is dependent on the sign of β,whenβis a positive, the direction is agree with surface tension of the sol- id-vapor interface γ and vice versa.展开更多
The morphological instability of solid/liquid(S/L)interface during solidification will result in different patterns of microstructure.In this study,two dimension(2 D)and three dimension(3 D)in-situ observation of soli...The morphological instability of solid/liquid(S/L)interface during solidification will result in different patterns of microstructure.In this study,two dimension(2 D)and three dimension(3 D)in-situ observation of solid/liquid interfacial morphology transition in Al-Zn alloy during directional solidification were performed via X-ray imaging.Under a condition of increasing temperature gradient(G),the interface transition from dendritic pattern to cellular pattern,and then to planar growth with perturbation was captured.The effect of solidification parameter(the ratio of temperature gradient and growth velocity(v),G/v)on morphological instabilities was investigated and the experimental results were compared to classical"constitutional supercooling"theory.The results indicate that 2 D and 3 D evolution process of S/L interface morphology under the same thermal condition are different.It seems that the S/L interface in 2 D observation is easier to achieve planar growth than that in 3 D,implying higher S/L interface stability in 2 D thin plate samples.This can be explained as the restricted liquid flow under 2 D solidification which is beneficial to S/L interface stability.The in-situ observation in present study can provide coherent dataset for microstructural formation investigation and related model validation during solidification.展开更多
The effect of the pulsed magnetic field on the grain refinement of superalloy K4169 has been studied in directional solidification.In the presence of the solid-liquid interface condition,the distributions of the elect...The effect of the pulsed magnetic field on the grain refinement of superalloy K4169 has been studied in directional solidification.In the presence of the solid-liquid interface condition,the distributions of the electromagnetic force,flow field,temperature field,and Joule heat in front of the solid-liquid interface in directional solidification with the pulsed magnetic field are simulated.The calculation results show that the largest electromagnetic force in the melt appears near the solid-liquid interface,and the electromagnetic force is distributed in a gradient.There are intensive electromagnetic vibrations in front of the solid-liquid interface.The forced melt convection is mainly concentrated in front of the solid-liquid interface,accompanied by a larger flow velocity.The simulation results indicate that the grain refinement is attributed to that the electromagnetic vibration and forced convection increase the nucleation rate and the probability of dendrite fragments survival,for making dendrite easily fragmented,homogenizing the melt temperature,and increasing the undercooling in front of the solid-liquid interface.展开更多
A method to predict the solid-liquid interface stability during unidirectional solidification is developed by coupling M-S model with CALPHAD method. The method was applied to AI-0.38 Zn and AI-0.34 Si-0.14 Mg (wt pct...A method to predict the solid-liquid interface stability during unidirectional solidification is developed by coupling M-S model with CALPHAD method. The method was applied to AI-0.38 Zn and AI-0.34 Si-0.14 Mg (wt pct) alloys, and the predicted results were compared with some former experimental data of the two alloys. The good agreement between the calculation results and the experimental data demonstrates the superiority of the present method to the classical one based on constant parameter assumptions.展开更多
The micro-morphology of the interface transition from(0112)facet to freezing isotherm curve has been observed.In the centre of the interface(the high supercooling region), the morphology of(0112)facet shows characteri...The micro-morphology of the interface transition from(0112)facet to freezing isotherm curve has been observed.In the centre of the interface(the high supercooling region), the morphology of(0112)facet shows characteristics of terrace-step-kink structure.By reducing supercoolings the growth interface gradually turn to agreeing with the freezing isotherm curve.展开更多
When current passes through the solid-liquid interface, the growth rate of crystal, solid-liquid interface energy and radius of curvature at dendritic tip will change. Based on this fact, the theoretical relation betw...When current passes through the solid-liquid interface, the growth rate of crystal, solid-liquid interface energy and radius of curvature at dendritic tip will change. Based on this fact, the theoretical relation between the distribution of solute at solid-liquid interface and current density was established, and the effect of current on the distribution coefficient of solute through effecting the rate of crystal growth, the solid-liquid interface energy and the radius of curvature at the dendritic tip was discussed. The results show that as the current density increases, the distribution coefficient of solute tends to rise in a whole, and when the former is larger than about 400 A/cm 2, the latter varies significantly.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
A particular kind of triboelectrification occurs during the flow of liquids through tubes.Here,we used Faraday cups and Kelvin probes to investigate the charge of aqueous solutions and alcohols flowing through a polyt...A particular kind of triboelectrification occurs during the flow of liquids through tubes.Here,we used Faraday cups and Kelvin probes to investigate the charge of aqueous solutions and alcohols flowing through a polytetrafluorethylene tube.An excess of positive charges was observed in all liquids collected by the Faraday cup after the flow.While the tube displays a small potential during the flow,likely due to electrokinetic effects,a very high negative potential was observed after the completion of the flow.Aqueous solutions with varying pH showed significant differences in charge accumulation only at pH 2.93 and 4.99,while most of the charge accumulation can be suppressed using common surfactants.Alcohols displayed an inverse relationship between charge accumulation and carbon chain length,except for methanol.Thus,we used graphite-based nanocomposites as noncontact induction electrodes near the tube for flow sensing.A proof of concept was conducted using these induction electrodes to differentiate between water and ethanol flowing inside the tube,which was repeated thousands of times.Finally,the output voltage signal from the induction electrode was processed through an input signal filter and a microcontroller,where four lightemitting diodes(LEDs)were incorporated to indicate the flow and type of liquid.展开更多
High-temperature ablation is a common failure phenomenon that limits the service life of the transmission parts on heavy-duty machines used in heavy load,high temperature,high shock conditions due to in-sufficient sup...High-temperature ablation is a common failure phenomenon that limits the service life of the transmission parts on heavy-duty machines used in heavy load,high temperature,high shock conditions due to in-sufficient supply of lubricating oil and grease.Traditional self-lubricating coatings prepared by inorganic,organic or organic-inorganic hybrid methods are prone to be oxidated at high temperatures to lose their friction reducing function,so that it is difficult to meet the engineering requirements of high-temperature lubrication.We design viscoelastic polymer coatings by a high-temperature self-lubricating and wear-resistant strategy.Polytetrafluoroethylene(PTFE,T_(m)=329℃)and polyphenylene sulfide(PPS,T_(g)=84℃,T_(m)=283℃)are used to prepare a PTFE/PPS polymer alloy coating.As the temperature increases from 25 to 300℃,the PTFE/PPS coating softens from glass state to viscoelastic state and viscous flow state,which is owing to the thermodynamic transformation characteristic of the PPS component.Additionally the friction coefficient(μ)decreased from 0.096 to 0.042 with the increasing of temperature from 25 to 300℃.The mechanism of mechanical deformation and surface morphology evolution for the PTFE/PPS coating under the multi-field coupling action of temperature(T),temperature–centrifugal force(T–F_(ω)),temperature–centrifugal force–shearing force(T–F_(ω)–F_(τ))were investigated.The physical model of“thermoviscoelasticity driven solid–liquid interface reducing friction”is proposed to clarify the self-lubricating mechanism determined by the high-temperature viscoelastic properties of polymers.The high-temperature adjusts the viscosity(η)of the coating,increases interface slipping and intensifies shear deformation(τ),reducing the friction coefficient.The result is expected to provide a new idea for designing anti-ablation coatings served in high temperature friction and wear conditions.展开更多
The solid-liquid interfacial thermal transport depends on the physical properties of the interfaces,which have been studied extensively in open literature.However,the fundamental understanding on the mechanism of the ...The solid-liquid interfacial thermal transport depends on the physical properties of the interfaces,which have been studied extensively in open literature.However,the fundamental understanding on the mechanism of the solid-liquid interfacial thermal transport is far from clear.In the present paper,heat transfer through solid-liquid interfaces is studied based on the non-equilibrium molecular dynamics simulations.It is shown that the interfacial heat transfer can be enhanced by increasing interfacial coupling strength or introducing the nanostructured surfaces.The underlying mechanism of the interfacial thermal transport is analyzed based on the calculation results of the heat flux distribution,potential mean force,and the vibrational density of states at the interfacial region.It is found that the interfacial thermal transport is dominated by the kinetic and virial contributions in the interface region.The enhancement of the interfacial heat transfer can be attributed to the fluid adsorption on the solid surface under a strong interfacial interaction or by the nanostructured solid surfaces,which reduce the mismatch of the vibrational density of states at the solid-liquid interface region.展开更多
In this work,the advantage of Coulomb repulsion in the intermolecular forces experienced by molecules on the solid–liquid nanosized contact interface is taken,and the superior friction-reducing property of Cu_(3)(PO_...In this work,the advantage of Coulomb repulsion in the intermolecular forces experienced by molecules on the solid–liquid nanosized contact interface is taken,and the superior friction-reducing property of Cu_(3)(PO_(4))2·3H_(2)O(CuP)oil-based additives has been confirmed for titanium alloy.Three-dimensional(3D)CuP nanoflowers(CuP-Fs)with a strong capillary absorption effect are prepared to achieve the homogeneous mixing of solid CuP and lubricating oil.Lubrication by CuP-Fs additives for titanium alloy,friction coefficient(COF)can be reduced by 73.68%,and wear rate(WR)reduced by 99.69%.It is demonstrated that the extraordinary friction-reducing property is due to the repulsive solid–liquid interface with low viscous shear force originating from Coulomb repulsion between polar water molecules in CuP and non-polar oil molecules.However,any steric hindrance or connection between this repulsive solid–liquid interface will trigger the adhesion and increase the viscous shear force,for example,dispersant,hydrogen bondings,and shaky adsorbed water molecules.Besides,the lamellar thickness of CuP and the molecular size of lubricant both have a great influence on tribological properties.Here the lubrication mechanism based on interface Coulomb repulsion is proposed that may help broaden the scope of the exploration in low-friction nanomaterial design and new lubricant systems.展开更多
Efficient utilization of electrostatic charges is paramount for numerous applications,from printing to kinetic energy harvesting.However,existing technologies predominantly focus on the static qualities of these charg...Efficient utilization of electrostatic charges is paramount for numerous applications,from printing to kinetic energy harvesting.However,existing technologies predominantly focus on the static qualities of these charges,neglecting their dynamic capabilities as carriers for energy conversion.Herein,we report a paradigm-shifting strategy that orchestrates the swift transit of surface charges,generated through contact electrification,via a freely moving droplet.This technique ingeniously creates a bespoke charged surface which,in tandem with a droplet acting as a transfer medium to the ground,facilitates targeted charge displacement and amplifies electrical energy collection.The spontaneously generated electric field between the charged surface and needle tip,along with the enhanced water ionization under the electric field,proves pivotal in facilitating controlled charge transfer.By coupling the effects of charge self-transfer,contact electrification,and electrostatic induction,a dual-electrode droplet-driven(DD)triboelectric nanogenerator(TENG)is designed to harvest the water-related energy,exhibiting a two-orderof-magnitude improvement in electrical output compared to traditional single-electrode systems.Our strategy establishes a fundamental groundwork for efficient water drop energy acquisition,offering deep insights and substantial utility for future interdisciplinary research and applications in energy science.展开更多
Oil film vortex severely reduces the stability of hydrostatic bearings. A solid-liquid interface with drag and slip properties can weaken the oil film vortex of the bearing. Here, a combined picosecond laser ablation ...Oil film vortex severely reduces the stability of hydrostatic bearings. A solid-liquid interface with drag and slip properties can weaken the oil film vortex of the bearing. Here, a combined picosecond laser ablation and chemical modification method is proposed to prepare surfaces with microbulge array structure on 6061 aluminum alloy substrates. Because of the low surface energy of the perfluorododecyltriethoxysilane modification and the bulge geometry of the microbulge array structure, the surface shows excellent superhydrophobicity. The optimum contact angle in air for water is 164°, and that for oil is 139°. Two surfaces with “lotus-leaf effect” and “rose-petal effect” were obtained by controlling the processing parameters. The drag reduction properties of superhydrophobic surfaces were systematically investigated with slip lengths of 22.26 and 36.25 μm for deionized water and VG5 lubricant, respectively. In addition, the superhydrophobic surface exhibits excellent mechanical durability and thermal stability. The proposed method provides a new idea for vortex suppression in hydrostatic bearings and improves the stability of bearings in high-speed operation.展开更多
Morphological evolution of the solid-liquid interface near grain boundaries has been studied during directional solidification of succinonitrile-based transparent alloys (SCN-0.9wt%DCB). Experimental results show that...Morphological evolution of the solid-liquid interface near grain boundaries has been studied during directional solidification of succinonitrile-based transparent alloys (SCN-0.9wt%DCB). Experimental results show that the grain boundary provides the starting point of morphological instability of the solid-liquid interface. The initial perturbation near the grain boundary is significantly larger than other perturbations on the interface. The initial shape of the interface and the competition between the thermal direction and preferred crystalline orientations determine the subsequent growth pattern selections. The temporal variations of the curvature radius of cell/ridge tips near the grain boundary have also been studied when the instability occurs. This process is divided into three parts. As the pulling velocity increases, dendrites at the grain boundary grow in two different directions to form a bicrystal microstructure. Side branches on either side of the dendrite exhibit different growth patterns.展开更多
Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent.Multi-component interface engineering is con...Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent.Multi-component interface engineering is considered an effective means to achieve high-efficiency EMW absorption.However,interface modulation engineering has not been fully discussed and has great potential in the field of EMW absorption.In this study,multi-component tin compound fiber composites based on carbon fiber(CF)substrate were prepared by electrospinning,hydrothermal synthesis,and high-temperature thermal reduction.By utilizing the different properties of different substances,rich heterogeneous interfaces are constructed.This effectively promotes charge transfer and enhances interfacial polarization and conduction loss.The prepared SnS/SnS_(2)/SnO_(2)/CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt%in epoxy resin.The minimum reflection loss(RL)is−46.74 dB and the maximum effective absorption bandwidth is 5.28 GHz.Moreover,SnS/SnS_(2)/SnO_(2)/CF epoxy composite coatings exhibited long-term corrosion resistance on Q235 steel surfaces.Therefore,this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments.展开更多
The pre-wetting of aggregate surface is a means to improve the interface performance of SBS modified asphalt and aggregate.The effect of pre-wetting technology on the interaction between SBS modified asphalt and aggre...The pre-wetting of aggregate surface is a means to improve the interface performance of SBS modified asphalt and aggregate.The effect of pre-wetting technology on the interaction between SBS modified asphalt and aggregate was analyzed by molecular dynamics simulation.The diffusion coefficient and concentration distribution of SBS modified asphalt on aggregate surface are included.The simulation results show that the diffusion coefficient of the aggregate surface of SBS modified asphalt is increased by 47.6%and 70.5%respectively after 110#asphalt and 130#asphalt are pre-wetted.The concentration distribution of SBS modified asphalt on the aggregate surface after pre-wetting is more uniform.According to the results of interface energy calculation,the interface energy of SBS modified bitumen and aggregate can be increased by about 5%after pre-wetting.According to the results of molecular dynamics simulation,the pre-wetting technology can effectively improve the interface workability of SBS modified bitumen and aggregate,so as to improve the interface performance.展开更多
基金supported by the Fundamental Research Program of Shanxi Province(202403021221148)the Taiyuan University of Science and Technology Graduate Education Innovation Project(SY2023001)+1 种基金the Special Funding Projects for Local Science and Technology Development guided by the Central Committee(YDZJSX2022C028)the Shanxi Province Research and Innovation Project(2024KY656)。
文摘Aluminum-air batteries(AABs)are considered the most promising candidates in advanced clean energy conversion and storage due to their low density,high specific energy,and abundant aluminum resources;however,the development of AABs is constrained by inevitable parasitic side reactions and anodic surface passivation film formation.The present work introduced an innovative hybrid corrosion inhibitor consisting of potassium stannate,decyl glucoside,and 1,10-decanedithiol to regulate solid-liquid interface reactions in alkaline AABs.The findings indicated that the optimal hybrid corrosion inhibitor could reduce the hydrogen evolution rate from 0.2095 to 0.0406 mL cm^(-2)min^(-1),achieving an inhibition efficiency of 80.62%.The surface analysis discussed in detail the evolution process of the solid-liquid interface after the introduction of the hybrid corrosion inhibitor into the battery.Experiments and theoretical calculations revealed that decyl glucoside enhanced the adsorption and coverage efficiency of the hybrid corrosion inhibitor through the“micelle solubilization”effect and optimized the structure and properties of the solid-liquid interface.This study also contributed valuable insights into the corrosion inhibition mechanism at the solid-liquid interface of alkaline AABs.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 59734080 and 59504006)the Project of National Fundamental Research and Development of China (Grant No. G1998061510) and High-Tech Research and Development Project
文摘Whether the particle will be trapped by the solid-liquid interface or not is dependent on its moving behavior ahead of the interface, so a mathematical model has been developed to investigate the movement of the particle ahead of the solid-liquid interface. Based on the theory for the boundary layer, the fluid velocity field near the solid-liquid interface was obtained, and the trajectories of particles were calculated by the equations of motion for particles. In this model, the drag force, the added mass force, the buoyance force, the gravitational force, the Saffman force and the Basset history force are considered. The results show that the behavior of the particle ahead of the solid-liquid interface is affected by the physical property of the particle and fluid flow. And in the continuous casting process, if it moves in the stream directed upward or downward near vertical solid-liquid interface or in the horizontal flow under the solid-liquid interface, the particle with the diameter from 5 um to 60um can reach the solid-liquid interface. But if it moves in horizontal flow above the solid-liquid interface, only the particle with the diameter from 5 um to 10 um can reach the solid-liquid interface.
基金financially supported by the National Natural Science Foundation of China(Nos.51772296,5217020858,51902016 and 21975015)the Fundamental Research Funds for the Central Universities(Nos.buctrc201829 and buctrc201904)。
文摘Self-assembly of nanoparticles at solid-liquid interface could be promising to realize the assembled functions for various applications,such as rechargeable batteries,supercapacitors,and electrocatalysis.This review summarizes the self-assembly of the nanoparticles at solid-liquid interface according to the different driving forces of assembly,including hydrophilic-hydrophobic interactions,solvophobic and electrostatic interaction.To be specific,the self-assembly can be divided into the following two types:surfactant-assisted self-assembly and direct self-assembly of Janus particles(inorganic and amphiphilic copolymer-inorganic Janus nanoparticles).Using the emulsion stabilized by nanoparticles as the template,the self-assembly constructed by the interaction of the nanostructure unit(including metal,metal oxide,and semiconductor,etc.)not only possesses the characteristic of nanostructure unit,but also exhibits the excellent assembly performance in electrochemistry aspect.The application of these assemblies in the area of electrochemical capacitors is presented.Finally,the current research progress and perspectives toward the self-assembly of nanoparticles at stabilized solid-liquid interface are proposed.
基金This work was financially supported by the National Natural Science Foundation of China (No.50371006).
文摘The solidification microstructure and fractal characteristics of the solid-liquid interfaces of Inconel 718,under different cooling rates during directional solidification,were investigated by using SEM. Results showed that 5 μm/s was the cellular-dendrite transient rate. The prime dendrite arm spacing (PDAS) was measured by Image Tool and it decreased with the cooling rate increased. The fractal dimension of the interfaces was calculated and it changes from 1.204310 to 1.517265 with the withdrawal rate ranging from 10 to 100 μm/s. The physical significance of the fractal dimension was analyzed by using fractal theory. It was found that the fractal dimension of the dendrites can be used to describe the solidification microstructure and parameters at low cooling rate,but both the fractal dimension and the dendrite arm spacing are needed in order to integrally describe the evaluation of the solidification microstructure completely.
文摘The paper presents a new relationship between the three surface tensions on the solid-liquid-vapor interface, γ_(sl)-γ_(sv)+γ_(lv)cosθ=βin order to understand the wetting on the liquid-solid interface in the case of active adsorption.The authors suggest a new force“apparent active adsorption force”βto take part in the balance at the three interface lines of contact in the solid-liquid-vapor phases,its dimen- sion isβ=Σα_iRT(Γ_i^(sl)-Γ_i^(sv)+Γ_i^(lv)cosθ),and its direction is dependent on the sign of β,whenβis a positive, the direction is agree with surface tension of the sol- id-vapor interface γ and vice versa.
基金financially supported by National Natural Science Foundation of China(Grants 51690162,51604171 and 51701112)Shanghai Municipal Science and Technology Commission(No.17JC1400602)Shanghai Sailing Program(19YF1415900).
文摘The morphological instability of solid/liquid(S/L)interface during solidification will result in different patterns of microstructure.In this study,two dimension(2 D)and three dimension(3 D)in-situ observation of solid/liquid interfacial morphology transition in Al-Zn alloy during directional solidification were performed via X-ray imaging.Under a condition of increasing temperature gradient(G),the interface transition from dendritic pattern to cellular pattern,and then to planar growth with perturbation was captured.The effect of solidification parameter(the ratio of temperature gradient and growth velocity(v),G/v)on morphological instabilities was investigated and the experimental results were compared to classical"constitutional supercooling"theory.The results indicate that 2 D and 3 D evolution process of S/L interface morphology under the same thermal condition are different.It seems that the S/L interface in 2 D observation is easier to achieve planar growth than that in 3 D,implying higher S/L interface stability in 2 D thin plate samples.This can be explained as the restricted liquid flow under 2 D solidification which is beneficial to S/L interface stability.The in-situ observation in present study can provide coherent dataset for microstructural formation investigation and related model validation during solidification.
基金financially supported by the National Natural Science Foundation of China (No. 51674236)the Key Research and Development Program of Liaoning Province (No.2019JH2/10100009)+1 种基金the National Science and Technology Major Project (No.2017-Ⅵ-0003-0073)the National Key Research and Development Program (No.2018Y-FA0702900)。
文摘The effect of the pulsed magnetic field on the grain refinement of superalloy K4169 has been studied in directional solidification.In the presence of the solid-liquid interface condition,the distributions of the electromagnetic force,flow field,temperature field,and Joule heat in front of the solid-liquid interface in directional solidification with the pulsed magnetic field are simulated.The calculation results show that the largest electromagnetic force in the melt appears near the solid-liquid interface,and the electromagnetic force is distributed in a gradient.There are intensive electromagnetic vibrations in front of the solid-liquid interface.The forced melt convection is mainly concentrated in front of the solid-liquid interface,accompanied by a larger flow velocity.The simulation results indicate that the grain refinement is attributed to that the electromagnetic vibration and forced convection increase the nucleation rate and the probability of dendrite fragments survival,for making dendrite easily fragmented,homogenizing the melt temperature,and increasing the undercooling in front of the solid-liquid interface.
基金the State Key Fundamental Research Project(G2000067202-1).
文摘A method to predict the solid-liquid interface stability during unidirectional solidification is developed by coupling M-S model with CALPHAD method. The method was applied to AI-0.38 Zn and AI-0.34 Si-0.14 Mg (wt pct) alloys, and the predicted results were compared with some former experimental data of the two alloys. The good agreement between the calculation results and the experimental data demonstrates the superiority of the present method to the classical one based on constant parameter assumptions.
基金supported by the Science Fund of the Chinese Academy of Sciences。
文摘The micro-morphology of the interface transition from(0112)facet to freezing isotherm curve has been observed.In the centre of the interface(the high supercooling region), the morphology of(0112)facet shows characteristics of terrace-step-kink structure.By reducing supercoolings the growth interface gradually turn to agreeing with the freezing isotherm curve.
文摘When current passes through the solid-liquid interface, the growth rate of crystal, solid-liquid interface energy and radius of curvature at dendritic tip will change. Based on this fact, the theoretical relation between the distribution of solute at solid-liquid interface and current density was established, and the effect of current on the distribution coefficient of solute through effecting the rate of crystal growth, the solid-liquid interface energy and the radius of curvature at the dendritic tip was discussed. The results show that as the current density increases, the distribution coefficient of solute tends to rise in a whole, and when the former is larger than about 400 A/cm 2, the latter varies significantly.
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 Brazilian agencies MCTIC/CNPq(465452/2014-0),FAPESP(2014/50906-9),and CAPES-Finance Code 001 through INCT/INOMAT(National Institute for Complex Functional Materials)and MCT/Finep/CT-Infra 02/2010.Yan Araujo Santos da Campo acknowledges CAPES(88887.674802/2022-00)for receiving a master’s degree fellowship.Authors have used large language models(ChatGTP)to improve readability and language.
文摘A particular kind of triboelectrification occurs during the flow of liquids through tubes.Here,we used Faraday cups and Kelvin probes to investigate the charge of aqueous solutions and alcohols flowing through a polytetrafluorethylene tube.An excess of positive charges was observed in all liquids collected by the Faraday cup after the flow.While the tube displays a small potential during the flow,likely due to electrokinetic effects,a very high negative potential was observed after the completion of the flow.Aqueous solutions with varying pH showed significant differences in charge accumulation only at pH 2.93 and 4.99,while most of the charge accumulation can be suppressed using common surfactants.Alcohols displayed an inverse relationship between charge accumulation and carbon chain length,except for methanol.Thus,we used graphite-based nanocomposites as noncontact induction electrodes near the tube for flow sensing.A proof of concept was conducted using these induction electrodes to differentiate between water and ethanol flowing inside the tube,which was repeated thousands of times.Finally,the output voltage signal from the induction electrode was processed through an input signal filter and a microcontroller,where four lightemitting diodes(LEDs)were incorporated to indicate the flow and type of liquid.
基金The authors are grateful for the financial support from National Natural Science Foundation of China(No.52075560).
文摘High-temperature ablation is a common failure phenomenon that limits the service life of the transmission parts on heavy-duty machines used in heavy load,high temperature,high shock conditions due to in-sufficient supply of lubricating oil and grease.Traditional self-lubricating coatings prepared by inorganic,organic or organic-inorganic hybrid methods are prone to be oxidated at high temperatures to lose their friction reducing function,so that it is difficult to meet the engineering requirements of high-temperature lubrication.We design viscoelastic polymer coatings by a high-temperature self-lubricating and wear-resistant strategy.Polytetrafluoroethylene(PTFE,T_(m)=329℃)and polyphenylene sulfide(PPS,T_(g)=84℃,T_(m)=283℃)are used to prepare a PTFE/PPS polymer alloy coating.As the temperature increases from 25 to 300℃,the PTFE/PPS coating softens from glass state to viscoelastic state and viscous flow state,which is owing to the thermodynamic transformation characteristic of the PPS component.Additionally the friction coefficient(μ)decreased from 0.096 to 0.042 with the increasing of temperature from 25 to 300℃.The mechanism of mechanical deformation and surface morphology evolution for the PTFE/PPS coating under the multi-field coupling action of temperature(T),temperature–centrifugal force(T–F_(ω)),temperature–centrifugal force–shearing force(T–F_(ω)–F_(τ))were investigated.The physical model of“thermoviscoelasticity driven solid–liquid interface reducing friction”is proposed to clarify the self-lubricating mechanism determined by the high-temperature viscoelastic properties of polymers.The high-temperature adjusts the viscosity(η)of the coating,increases interface slipping and intensifies shear deformation(τ),reducing the friction coefficient.The result is expected to provide a new idea for designing anti-ablation coatings served in high temperature friction and wear conditions.
基金Beijing Nova Program of Science and Technology(No.Z191100001119033)。
文摘The solid-liquid interfacial thermal transport depends on the physical properties of the interfaces,which have been studied extensively in open literature.However,the fundamental understanding on the mechanism of the solid-liquid interfacial thermal transport is far from clear.In the present paper,heat transfer through solid-liquid interfaces is studied based on the non-equilibrium molecular dynamics simulations.It is shown that the interfacial heat transfer can be enhanced by increasing interfacial coupling strength or introducing the nanostructured surfaces.The underlying mechanism of the interfacial thermal transport is analyzed based on the calculation results of the heat flux distribution,potential mean force,and the vibrational density of states at the interfacial region.It is found that the interfacial thermal transport is dominated by the kinetic and virial contributions in the interface region.The enhancement of the interfacial heat transfer can be attributed to the fluid adsorption on the solid surface under a strong interfacial interaction or by the nanostructured solid surfaces,which reduce the mismatch of the vibrational density of states at the solid-liquid interface region.
基金the National Natural Science Foundation of China(Nos.51975421,52075405,and 51975420)Hubei Longzhong Laboratory Independent Innovation Research Project(No.2022ZZ-05).
文摘In this work,the advantage of Coulomb repulsion in the intermolecular forces experienced by molecules on the solid–liquid nanosized contact interface is taken,and the superior friction-reducing property of Cu_(3)(PO_(4))2·3H_(2)O(CuP)oil-based additives has been confirmed for titanium alloy.Three-dimensional(3D)CuP nanoflowers(CuP-Fs)with a strong capillary absorption effect are prepared to achieve the homogeneous mixing of solid CuP and lubricating oil.Lubrication by CuP-Fs additives for titanium alloy,friction coefficient(COF)can be reduced by 73.68%,and wear rate(WR)reduced by 99.69%.It is demonstrated that the extraordinary friction-reducing property is due to the repulsive solid–liquid interface with low viscous shear force originating from Coulomb repulsion between polar water molecules in CuP and non-polar oil molecules.However,any steric hindrance or connection between this repulsive solid–liquid interface will trigger the adhesion and increase the viscous shear force,for example,dispersant,hydrogen bondings,and shaky adsorbed water molecules.Besides,the lamellar thickness of CuP and the molecular size of lubricant both have a great influence on tribological properties.Here the lubrication mechanism based on interface Coulomb repulsion is proposed that may help broaden the scope of the exploration in low-friction nanomaterial design and new lubricant systems.
基金supported by the Natural Science Foundation of Zhejiang Province(LZ22C130001)the National Natural Science Foundation of China(32171887,and 52002028,and 52192610)+1 种基金the National Key Research and Development Project from Minister of Science&Technology(2021YFA0202704)Beijing Municipal Science&Technology Commission(Z171100002017017).
文摘Efficient utilization of electrostatic charges is paramount for numerous applications,from printing to kinetic energy harvesting.However,existing technologies predominantly focus on the static qualities of these charges,neglecting their dynamic capabilities as carriers for energy conversion.Herein,we report a paradigm-shifting strategy that orchestrates the swift transit of surface charges,generated through contact electrification,via a freely moving droplet.This technique ingeniously creates a bespoke charged surface which,in tandem with a droplet acting as a transfer medium to the ground,facilitates targeted charge displacement and amplifies electrical energy collection.The spontaneously generated electric field between the charged surface and needle tip,along with the enhanced water ionization under the electric field,proves pivotal in facilitating controlled charge transfer.By coupling the effects of charge self-transfer,contact electrification,and electrostatic induction,a dual-electrode droplet-driven(DD)triboelectric nanogenerator(TENG)is designed to harvest the water-related energy,exhibiting a two-orderof-magnitude improvement in electrical output compared to traditional single-electrode systems.Our strategy establishes a fundamental groundwork for efficient water drop energy acquisition,offering deep insights and substantial utility for future interdisciplinary research and applications in energy science.
基金supported by the National Key R&D Program of China(Grant No. 2020YFB2007600)National Natural Science Foundation of China(Grant Nos. 51875223 and 52188102)Guangdong HUST Industrial Technology Research Institute, Guangdong Provincial Key Laboratory of Manufacturing Equipment Digization(Grant No. 2020B1212060014)。
文摘Oil film vortex severely reduces the stability of hydrostatic bearings. A solid-liquid interface with drag and slip properties can weaken the oil film vortex of the bearing. Here, a combined picosecond laser ablation and chemical modification method is proposed to prepare surfaces with microbulge array structure on 6061 aluminum alloy substrates. Because of the low surface energy of the perfluorododecyltriethoxysilane modification and the bulge geometry of the microbulge array structure, the surface shows excellent superhydrophobicity. The optimum contact angle in air for water is 164°, and that for oil is 139°. Two surfaces with “lotus-leaf effect” and “rose-petal effect” were obtained by controlling the processing parameters. The drag reduction properties of superhydrophobic surfaces were systematically investigated with slip lengths of 22.26 and 36.25 μm for deionized water and VG5 lubricant, respectively. In addition, the superhydrophobic surface exhibits excellent mechanical durability and thermal stability. The proposed method provides a new idea for vortex suppression in hydrostatic bearings and improves the stability of bearings in high-speed operation.
基金supported by the National Natural Science Foundation of China (Grant Nos.61078057 and 51172183)NPU Foundation for Fundamental Research (Grant Nos.NPU-FFR-JC201048 and JC201155)+1 种基金the Science & Technology Program of Shanghai Maritime University (Grant No.20110054)the Project of the Excellent Youth of Shanghai (WANG CaiFang)
文摘Morphological evolution of the solid-liquid interface near grain boundaries has been studied during directional solidification of succinonitrile-based transparent alloys (SCN-0.9wt%DCB). Experimental results show that the grain boundary provides the starting point of morphological instability of the solid-liquid interface. The initial perturbation near the grain boundary is significantly larger than other perturbations on the interface. The initial shape of the interface and the competition between the thermal direction and preferred crystalline orientations determine the subsequent growth pattern selections. The temporal variations of the curvature radius of cell/ridge tips near the grain boundary have also been studied when the instability occurs. This process is divided into three parts. As the pulling velocity increases, dendrites at the grain boundary grow in two different directions to form a bicrystal microstructure. Side branches on either side of the dendrite exhibit different growth patterns.
基金financially supported by the National Natural Science Foundation of China(No.52377026 and No.52301192)Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)+4 种基金Postdoctoral Fellowship Program of CPSF under Grant Number(No.GZB20240327)Shandong Postdoctoral Science Foundation(No.SDCXZG-202400275)Qingdao Postdoctoral Application Research Project(No.QDBSH20240102023)China Postdoctoral Science Foundation(No.2024M751563)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites).
文摘Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent.Multi-component interface engineering is considered an effective means to achieve high-efficiency EMW absorption.However,interface modulation engineering has not been fully discussed and has great potential in the field of EMW absorption.In this study,multi-component tin compound fiber composites based on carbon fiber(CF)substrate were prepared by electrospinning,hydrothermal synthesis,and high-temperature thermal reduction.By utilizing the different properties of different substances,rich heterogeneous interfaces are constructed.This effectively promotes charge transfer and enhances interfacial polarization and conduction loss.The prepared SnS/SnS_(2)/SnO_(2)/CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt%in epoxy resin.The minimum reflection loss(RL)is−46.74 dB and the maximum effective absorption bandwidth is 5.28 GHz.Moreover,SnS/SnS_(2)/SnO_(2)/CF epoxy composite coatings exhibited long-term corrosion resistance on Q235 steel surfaces.Therefore,this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments.
基金Funded by the Research Funds of China University of Mining and Technology(No.102523215)。
文摘The pre-wetting of aggregate surface is a means to improve the interface performance of SBS modified asphalt and aggregate.The effect of pre-wetting technology on the interaction between SBS modified asphalt and aggregate was analyzed by molecular dynamics simulation.The diffusion coefficient and concentration distribution of SBS modified asphalt on aggregate surface are included.The simulation results show that the diffusion coefficient of the aggregate surface of SBS modified asphalt is increased by 47.6%and 70.5%respectively after 110#asphalt and 130#asphalt are pre-wetted.The concentration distribution of SBS modified asphalt on the aggregate surface after pre-wetting is more uniform.According to the results of interface energy calculation,the interface energy of SBS modified bitumen and aggregate can be increased by about 5%after pre-wetting.According to the results of molecular dynamics simulation,the pre-wetting technology can effectively improve the interface workability of SBS modified bitumen and aggregate,so as to improve the interface performance.
