The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100),and the microstructures,mechanical and tribological properties we...The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100),and the microstructures,mechanical and tribological properties were investigated from 25 to 700℃.The results showed that the surface roughness and average grain size of VN/Ag coatings with transition multilayer interface are obviously larger than those of VN/Ag coatings with heterogeneous multilayer interface.The coatings with transition multilayer interface have higher adhesion force and hardness than the coatings with heterogeneous multilayer interface,and both coatings can effectively restrict the initiation and propagation of microcracks.Both coatings have excellent self-adaptive lubricating properties with a decrease of friction coefficient as the temperature increases,but their wear rates reveal a drastic increase.The phase composition of the worn area of both coatings was investigated,which indicates that a smooth Ag,Magnéli phase(V2O5)and bimetallic oxides(Ag3VO4 and AgVO3)can be responsible to the excellent lubricity of both coatings.To sum up,the coatings with transition multilayer interface have excellent adaptive lubricating properties and can properly control the diffusion rate and release rate of the lubricating phase,indicating that they have great potential in solving the problem of friction and wear of mechanical parts.展开更多
Surface/interface engineering plays an important role in improving the performance and economizing the cost and usage of electrocatalysts.In recent years,substantial progress has been achieved in designing and develop...Surface/interface engineering plays an important role in improving the performance and economizing the cost and usage of electrocatalysts.In recent years,substantial progress has been achieved in designing and developing highly active electrocatalysts with the deepening understanding of surface and interface enhanced mechanism.In this review,recent development about optimizing the surface and interfacial structure in promoting the electrocatalytic activity of noble-metals and transition metal compounds is presented and the chemical enhancements are also described in detail.The relationship between the surface/interface structures(both atomic and electronic configuration)and the electrochemical behaviors has been discussed.Finally,personal perspectives have been proposed,highlighting the challenges and opportunities for future development in tuning the surface/interface active sites of electrocatalysts.We believe that this timely review will be beneficial to the construction of highly active and durable electrode materials through optimizing surface atomic arrangement and interfacial interaction,which can largely promote the development of next-generation clean energy conversion technologies.展开更多
The deformation incompatibility of components is a bottleneck restricting the exaltation of the strength and ductility of composites.Herein,the coherent transition interface was designed and produced in hexagonal boro...The deformation incompatibility of components is a bottleneck restricting the exaltation of the strength and ductility of composites.Herein,the coherent transition interface was designed and produced in hexagonal boron nitride nanosheets(BNNSs)/Al composites by reaction sintering route,expecting to re-lieve the deformation incompatibility between BNNSs and Al.It is demonstrated that with the sintering temperature for composites raising from 600℃ to 650℃,700℃ and 750℃,different interface bonding characteristics,which involve nucleation and growth of AlN continuous nanolayer,were confirmed.Fur-thermore,first-principles calculations show that the generation of the coherent transition interface im-proved the interfacial bonding strength of BNNSs/Al composites through covalent bonds.The composites with coherent transition interface exhibit excellent strength-toughness combination in tensile and impact tests.The finite element simulation and in-situ approach under tensile tests were applied to investigate the influence of transition interface structure on deformation behavior of BNNSs/Al composite.It is found that the generation of the transition interface can not only weaken the stress partitioning behavior in the elastic stage,but also constrain the crack initiation and propagation behavior in the elastic-plastic stage and plastic stage,thereby improving the deformation compatibility between BNNSs and Al.The present work provides a novel view into the breakthrough for the trade-offrelationship of strength and ductility by coherent transition interface design in nanocomposites.展开更多
The interface morphologies and microstruetures of the directionally solidified Ni-5wt-% Cu alloy during dendrite-to-cell transition at high growth rates have been investigated with a newly developed apparatus for unid...The interface morphologies and microstruetures of the directionally solidified Ni-5wt-% Cu alloy during dendrite-to-cell transition at high growth rates have been investigated with a newly developed apparatus for unidirectional solidification with the temperature gradient at the solid/liquid interface higher than 1000 K/cm.The results show that in the vicinity of dendrite-to-cell transition point,the well developed sidebranches become shrivelled with the increase of growth rate and disappear at the dendrite-to-cell transition,and the primary spacing decreases simultaneously.Moreover,the length of mushy zone decreases greatly dur- ing the dendrite-to-cell transition.Cells obtained at high growth rates have very similar morphologies to those at low growth rates,but with much smaller cell spacings and unsmoothed cell walls which may be attributed to the different stability conditions of the cell walls at low and high growth rates respectively.展开更多
The temperature gradients that arise in the paraelectric-ferroelectric interface dynamics induced by the latent heat transfer are studied from the point of view that a ferroelectric phase transition is a stationary, t...The temperature gradients that arise in the paraelectric-ferroelectric interface dynamics induced by the latent heat transfer are studied from the point of view that a ferroelectric phase transition is a stationary, thermal-electric coupled transport process. The local entropy production is derived for a ferroelectric phase transition system from the Gibbs equation. Three types of regions in the system are described well by using the Onsager relations and the principle of minimum entropy production. The theoretical results coincides with the experimental ones.展开更多
Compared to the sandstone-type uranium deposits in the Ordos Basin and the Songliao Basin,the Tamusu uranium deposit in the Bayingobi Basin formed in fault-depression transition region displays distinctive features.Fi...Compared to the sandstone-type uranium deposits in the Ordos Basin and the Songliao Basin,the Tamusu uranium deposit in the Bayingobi Basin formed in fault-depression transition region displays distinctive features.First,the uranium-bearing sandstones and their interlayer oxidation zone extend longitudinally no more than ten kilometers.Second,gravity flow sediments are more common in the uranium-bearing strata.Comprehensive facies analysis indicates that the Upper Member(orebearing horizon)of the Bayingobi Formation was largely deposited in fan deltas that prograded into lakes during period of relatively dry paleoclimate.Spatial distribution patterns of five facies associations along with two depositional environments(fan delta,lake)were reconstructed in this study.The results demonstrated that the depositional systems and their inner genetic facies played different roles in uranium reservoir sandstone,confining beds(isolated barrier beds)and reduction geologic bodies during uranium mineralization process.展开更多
Interface and scale effects are the two most important factors which strongly affect the structure and the properties of nano-/micro-crystals under pressure.We conduct an experiment under high pressure in situ alterna...Interface and scale effects are the two most important factors which strongly affect the structure and the properties of nano-/micro-crystals under pressure.We conduct an experiment under high pressure in situ alternating current impedance to elucidate the effects of interface on the structure and electrical transport behavior of two Zn Se samples with different sizes obtained by physical grinding.The results show that（i） two different-sized Zn Se samples undergo the same phase transitions from zinc blend to cinnabar-type phase and then to rock salt phase;（ii） the structural transition pressure of the859-nm Zn Se sample is higher than that of the sample of 478 nm,which indicates the strong scale effect.The pressure induced boundary resistance change is obtained by fitting the impedance spectrum,which shows that the boundary conduction dominates the electrical transport behavior of Zn Se in the whole experimental pressure range.By comparing the impedance spectra of two different-sized Zn Se samples at high pressure,we find that the resistance of the 478-nm Zn Se sample is lower than that of the 859-nm sample,which illustrates that the sample with smaller particle size has more defects which are due to physical grinding.展开更多
The sufficient bond between concrete and rock is an important prerequisite to ensure the effect of shotcrete support. However, in cold regions engineering protection system, the bond condition of rock and concrete sur...The sufficient bond between concrete and rock is an important prerequisite to ensure the effect of shotcrete support. However, in cold regions engineering protection system, the bond condition of rock and concrete surface is easily affected by freeze-thaw cycles, resulting in interface damage, debonding and even supporting failure. Understanding the micromechanisms of the damage and debonding of the rock-concrete interface is essential for improving the interface protection.Therefore, the micromorphology, micromechanical properties, and microdebonding evolution of the sandstone-concrete interface transition zone(ITZ) under varying freeze-thaw cycles(0, 5, 10, 15, 20) were studied using scanning electron microscope, stereoscopic microscope, and nano-indentation. Furthermore, the distribution range and evolution process of ITZ affected by freeze-thaw cycles were defined. Major findings of this study are as follows:(1) The microdamage evolution law of the ITZ under increasing freeze-thaw cycles is clarified, and the relationship between the number of cracks in the ITZ and freeze-thaw cycles is established;(2) As the number of freeze-thaw cycles increases, the ITZ's micromechanical strength decreases, and its development width tends to increase;(3) The damage and debonding evolution mechanisms of sandstone-concrete ITZ under freeze-thaw cycles is revealed, and its micromechanical evolution model induced by freeze-thaw cycles is proposed.展开更多
Zn-air batteries(ZABs),especially the secondary batteries,have engrossed a great interest because of its high specific energy,economical and high safety.However,due to the insufficient activity and stability of bifunc...Zn-air batteries(ZABs),especially the secondary batteries,have engrossed a great interest because of its high specific energy,economical and high safety.However,due to the insufficient activity and stability of bifunctional electrocatalysts for air-cathode oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)processes,the practical application of rechargeable ZABs is seriously hindered.In the effort of developing high active,stable and cost-effective electrocatalysts,transition metal nitrides(TMNs)have been regarded as the candidates due to their high conductivity,strong corrosion-resistance,and bifunctional catalytic performance.In this paper,the research progress in TMNs-based material as ORR and OER electrocatalysts for ZABs is discussed with respect to their synthesis,chemical/physical characterization,and performance validation/optimization.The surface/interface nanoengineering strategies such as defect engineering,support binding,heteroatom introduction,crystal plane orientation,interface construction and small size effect,the physical and chemical properties of TMNs-based electrocatalysts are emphasized with respect to their structures/morphologies,composition,electrical conductivity,specific surface area,chemical stability and corrosion resistance.The challenges of TMNs-based materials as bifunctional air-cathode electrocatalysts in practical application are evaluated,and numerous research guidelines to solve these problems are put forward for facilitating further research and development.展开更多
Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectificatio...Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectification phenomenon in an asymmetric solid–liquid–solid sandwiched system with a nano-structured interface.By using the non-equilibrium molecular dynamics simulations,the thermal transport through the solid–liquid–solid system is examined,and the thermal rectification phenomenon can be observed.It is revealed that the thermal rectification effect can be attributed to the significant difference in the interfacial thermal resistance between Cassie and Wenzel states when reversing the temperature bias.In addition,effects of the liquid density,solid–liquid bonding strength and nanostructure size on the thermal rectification are examined.The findings may provide a new way for designs of certain thermal devices.展开更多
Based on the two-pass differential temperature rolling bonding method,the effects of prefabricated steel/aluminum composite panel temperature on interface characteristics and microstructure properties were investigate...Based on the two-pass differential temperature rolling bonding method,the effects of prefabricated steel/aluminum composite panel temperature on interface characteristics and microstructure properties were investigated through experimental analysis and finite element simulations.When the temperature exceeds 400℃,the effective preparation of the steel-aluminum transition joint can be achieved,and with the increase in temperature,the interface shear and pull-off strength of the steel-aluminum transition joint exhibits an initial decrease followed by an increase.Both the interface shear and pull-off fractures are in 1060 aluminum matrix.As the temperature increases,the size of the average grain in 1060 aluminum matrix increases and then decreases.When the temperature reaches 550℃,the comprehensive performance of the prepared steel-aluminum transition joint is the best,with the interface shear strength of 77 MPa and the interface pull-off strength of 153 MPa,exceeding the bonding strength of the explosive compounding method.There are no pinholes,wrinkles,or cracks in the lateral bending matrix and the interface.展开更多
Engineering oxygen vacancy formation and distribution is a powerful route for controlling the oxygen sublattice evolution that affects diverse functional behavior.The controlling of the oxygen vacancy formation proces...Engineering oxygen vacancy formation and distribution is a powerful route for controlling the oxygen sublattice evolution that affects diverse functional behavior.The controlling of the oxygen vacancy formation process is particularly important for inducing topotactic phase transitions that occur by transformation of the oxygen sublattice.Here we demonstrate an epitaxial nanocomposite approach for exploring the spatial control of topotactic phase transition from a pristine perovskite phase to an oxygen vacancy-ordered brownmillerite(BM)phase in a model oxide La_(0.7)Sr_(0.3)MnO_(3)(LSMO).Incorporating a minority phase NiO in LSMO films creates ultrahigh density of vertically aligned epitaxial interfaces that strongly influence the oxygen vacancy formation and distribution in LSMO.Combined structural characterizations reveal strong interactions between NiO and LSMO across the epitaxial interfaces leading to a topotactic phase transition in LSMO accompanied by significant morphology evolution in NiO.Using the NiO nominal ratio as a single control parameter,we obtain intermediate topotactic nanostructures with distinct distribution of the transformed LSMO-BM phase,which enables systematic tuning of magnetic and electrical transport properties.The use of self-assembled heterostructure interfaces by the epitaxial nanocomposite platform enables more versatile design of topotactic phase structures and correlated functionalities that are sensitive to oxygen vacancies.展开更多
Water electrolysis for green hydrogen production is important for the global carbon neutrality.The industrialization of this technology requires efficient and durable electrocatalysts under high-current-density(HCD)op...Water electrolysis for green hydrogen production is important for the global carbon neutrality.The industrialization of this technology requires efficient and durable electrocatalysts under high-current-density(HCD)operations.However,the insufficient mass and charge transfer at the various interfaces lead to unsatisfactory HCD activity and durability.Interface engineering is important for designing efficient HCD electrocatalysts.In this perspective,we analyze the processes taking place at three interfaces including the catalyst-substrate,catalyst-electrolyte,and catalyst-gas interfaces,and reveal the correlations between interface interactions and the challenges for HCD electrolysis.We then highlight the development of HCD electrocatalysts that focus on interface engineering using the example of transition metal dichalcogenide based catalysts,which have attracted widespread interests in recent years.Finally,we give an outlook on the development of interface engineering for the industrialization of water electrolysis technology.展开更多
At present there is no explanation of the nature of interface instability upon first order phase transitions. The well-known theory of concentration overcooling under directed crystallization of solutions and Mullins-...At present there is no explanation of the nature of interface instability upon first order phase transitions. The well-known theory of concentration overcooling under directed crystallization of solutions and Mullins-Sekerka instability cannot account for the diversified liquid component redistribution during solid state transition. In [1-3], within the framework of the nonequilibrium mass transfer problem, it has been shown that there are regimes of the interface instability, which differ from the known ones [4-6]. Moreover, the instability theory of works [1-3] demonstrates a complete experimental agreement of the dependence of eutectic pattern period on interface velocity. However, it is difficult to explain interface instability within the framework of a general setting of the mass-transfer problem. This paper is de-voted to qualitative analysis of the phenomena that are responsible for interface instability. The phenomena are connected by a single equation. Qualitative analysis revealed a variety of different conditions responsible for instability of flat interface stationary movement upon phase transition. The type of instability depends on system parameters. It is important that interface instability in the asymptotic case of quasi-equilibrium problem setting is qualitatively different from interface instability in the case of nonequilibrium problem setting.展开更多
The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and A...The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and Al_(3)Ni brittle intermetallic compounds(IMCs)under different conditions was investigated,and the formation mechanisms of dendritic Al_(3)Ni crystals with different morphologies were elucidated.The increasing remelting cycles accelerated the formation of Al_(3)Ni_(2) layer and the growth of Al_(3)Ni IMCs.The increased-step heating temperatures and time promoted the morphological transition from faceted to non-faceted dendritic Al_(3)Ni,which was attributed to the enhanced undercooling during solidification and incompletely remelted Al_(3)Ni IMCs during remelting.The growth of regular Al_(3)Ni dendrites was dominated by coalescence of secondary dendrite arms,while the growth of irregular dendrites Al_(3)Ni was controlled by dendrite merging,radial melting and axial melting of secondary arms.The axially free dendritic Al_(3)Ni was attributed to the small distance between adjacent main trunks,and the dense secondary arms promoted the formation of local solute depletion regions.展开更多
Layered transition metal dichalcogenides(TMDs)have emerged as promising electrode materials for supercapacitors due to their high theoretical specific capacitance,unique layered structure,large surface area,and tunabl...Layered transition metal dichalcogenides(TMDs)have emerged as promising electrode materials for supercapacitors due to their high theoretical specific capacitance,unique layered structure,large surface area,and tunable energy band structure.Substantial progress has been made in the development of TMDs for supercapacitors,with several great breakthroughs reported.However,the practical application of TMDs is still hindered by several challenges,including their susceptibility to oxidation,the tendency to restack or aggregate,structural instability,and interior electrical conductivity.To overcome these limitations,the construction of heterostructures has been identified as an effective strategy.By modulating the interface structure between different components,heterostructures can enhance overall structural stability and facilitate faster ion transport,thereby improving the efficiency of supercapacitors.This review provides a comprehensive overview of recent advances in TMD-based heterostructures for supercapacitors,focusing on their synthesis methods,the relationship between structure,properties,and electrochemical performance,as well as existing challenges.Particular emphasis is placed on hetero structure engineering strategies that integrate TMDs with materials of various dimensionalities(0D,1D,2D,and 3D)to enhance their electrochemical performance for supercapacitors.Finally,the review discusses critical challenges and outlines future perspectives that may guide the development of TMDs for supercapacitors and beyond.展开更多
The microstructure of ITZ (Interfacial Transition Zone) in single glass fibre-cement was investigated by SEM ( Scanning Electron Microscope), EPXM ( Electron Probe X-ray Microanalyzer) and ESEM (Environmental Scanning...The microstructure of ITZ (Interfacial Transition Zone) in single glass fibre-cement was investigated by SEM ( Scanning Electron Microscope), EPXM ( Electron Probe X-ray Microanalyzer) and ESEM (Environmental Scanning Electron Microscope) . The surface morphology of glass fibres and the hydration products in the vicinity of the interfaces were observed. Chemical element (Zr, Ca and Si) distributions over the ITZ thickness were determined by line-scanning with EPXM. The results show that a low-density transition zone existed in the vicinity of glass fibres . The shape of the fibre-cement ITZ was non-symmetrical and its thickness was variable . In the present study, the width of the zone ranged from 1 - 5 μm. Locally, it came to 10μm. Occasionally , some hydration products with high alkalinity were embedded inside the ITZ, and attached on the glass surface , making the ITZ denser and causing local glass to corrode. The test results are helpful for the further understanding of the GRC degradation .展开更多
Poly(lactic acid)(PLA)has attracted considerable interest as an environmentally friendly and biodegradable polymer.The properties of poly(L-lactic acid)(PLLA)at an air/water interface were studied based on the Langmui...Poly(lactic acid)(PLA)has attracted considerable interest as an environmentally friendly and biodegradable polymer.The properties of poly(L-lactic acid)(PLLA)at an air/water interface were studied based on the Langmuir-Blodgett(LB)film balance and atomic force microscopy(AFM).The surface pressure-area(E-A)isotherm indicated that the surface pressure of PLLA initially increased as the interfacial film was compressed;at Tr=9.0 mN·m^-1,a plateau was observed in the TT--A isotherm,in which the area of the repeat unit was in the approximate range 0.11-0.17 nm^2,The AFM results showed that there is a clear structural transition in the PLLA film during the compression:(i)at the beginning of the plateau,a number of fibrils are present at the air/water interface and(ii)multilayer structures(at least bilayer,i.e.,the underlying layer and top layer consisting of fibrils)is formed in the plateau region.In particular,when Tr=20.0 mN·m^-1,a thin film of PLLA of thickness about 6.0 nm was fabricated.Our findings suggest that the plateau in the PLLA Tr-A isotherm is closely related to a change in the film structure from monolayer to multilayer at the air/water interface.This is significantly different from the behavior of conventional amphiphiles,because the plateau in amphiphiles TT--A isotherm is equivalent to a phase transition of monolayers derived from amphiphiles in a two-dimensional plane.展开更多
Tectonic dynamic system transition, one of the main factors in metallogenesis, controls metallogenic fluid movement and ore body location in orefields and on an ore deposit scale (mainly in the continental tectonic se...Tectonic dynamic system transition, one of the main factors in metallogenesis, controls metallogenic fluid movement and ore body location in orefields and on an ore deposit scale (mainly in the continental tectonic setting), and even the formation and distribution of large-scale deposit clusters. Tectonic dynamic system transition can be classified as the spacious difference of the tectonic dynamic system in various geological units and the temporal alteration of different tectonic dynamic systems. The former results in outburst of mineralization, while the latter leads to the metallogenic diversity. Both of them are the main contents of metallogenic effect of tectonic dynamic system transition, that is, the alteration of dynamic system, the occurrence of mineralization, and the difference of regional tectonic dynamic system and metallogenic diversity. Generally speaking, the coupling of spatial difference of tectonic dynamic system and its successive alternation controlled the tempo-spatial evolution regularity of mineralization on a larger scale. In addition, the analysis of mineralization factors and processes of typical ore deposits proved that the changes of tectonic stress field, the direct appearance of tectonic dynamic system transition, may lead to the accident of mineralization physical-chemical field and the corresponding accidental interfaces were always located at ore bodies.展开更多
基金Project(51505100)supported by the National Natural Science Foundation of China
文摘The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100),and the microstructures,mechanical and tribological properties were investigated from 25 to 700℃.The results showed that the surface roughness and average grain size of VN/Ag coatings with transition multilayer interface are obviously larger than those of VN/Ag coatings with heterogeneous multilayer interface.The coatings with transition multilayer interface have higher adhesion force and hardness than the coatings with heterogeneous multilayer interface,and both coatings can effectively restrict the initiation and propagation of microcracks.Both coatings have excellent self-adaptive lubricating properties with a decrease of friction coefficient as the temperature increases,but their wear rates reveal a drastic increase.The phase composition of the worn area of both coatings was investigated,which indicates that a smooth Ag,Magnéli phase(V2O5)and bimetallic oxides(Ag3VO4 and AgVO3)can be responsible to the excellent lubricity of both coatings.To sum up,the coatings with transition multilayer interface have excellent adaptive lubricating properties and can properly control the diffusion rate and release rate of the lubricating phase,indicating that they have great potential in solving the problem of friction and wear of mechanical parts.
基金supported financially by the Joint Funds of National Natural Science Foundation of China and Guangdong Province(No.U1601216)the National Natural Science Foundation of China(Nos.51602216 and 51472178)+1 种基金Young Elite Scientists Sponsorship Program by CAST(No.2018QNRC001)Tianjin Natural Science Foundation(No.17JCQNJC02100).
文摘Surface/interface engineering plays an important role in improving the performance and economizing the cost and usage of electrocatalysts.In recent years,substantial progress has been achieved in designing and developing highly active electrocatalysts with the deepening understanding of surface and interface enhanced mechanism.In this review,recent development about optimizing the surface and interfacial structure in promoting the electrocatalytic activity of noble-metals and transition metal compounds is presented and the chemical enhancements are also described in detail.The relationship between the surface/interface structures(both atomic and electronic configuration)and the electrochemical behaviors has been discussed.Finally,personal perspectives have been proposed,highlighting the challenges and opportunities for future development in tuning the surface/interface active sites of electrocatalysts.We believe that this timely review will be beneficial to the construction of highly active and durable electrode materials through optimizing surface atomic arrangement and interfacial interaction,which can largely promote the development of next-generation clean energy conversion technologies.
基金This work was financially supported by the Chinese Na-tional Natural Science Fund for Distinguished Young Scholars(No.52025015)the Chinese National Natural Science Foundation Nos.51771130,52071230 and 52101181)+2 种基金the Tianjin Youth Tal-ent Support Program,the Tianjin Natural Science Funds for Dis-tinguished Young Scholars(No.17JCJQJC44300)the Tianjin Sci-ence and Technology Support Project(No.17ZXCLGX00060)the China Postdoctoral Science Foundation Nos.2020M670648 and 2021T140505).
文摘The deformation incompatibility of components is a bottleneck restricting the exaltation of the strength and ductility of composites.Herein,the coherent transition interface was designed and produced in hexagonal boron nitride nanosheets(BNNSs)/Al composites by reaction sintering route,expecting to re-lieve the deformation incompatibility between BNNSs and Al.It is demonstrated that with the sintering temperature for composites raising from 600℃ to 650℃,700℃ and 750℃,different interface bonding characteristics,which involve nucleation and growth of AlN continuous nanolayer,were confirmed.Fur-thermore,first-principles calculations show that the generation of the coherent transition interface im-proved the interfacial bonding strength of BNNSs/Al composites through covalent bonds.The composites with coherent transition interface exhibit excellent strength-toughness combination in tensile and impact tests.The finite element simulation and in-situ approach under tensile tests were applied to investigate the influence of transition interface structure on deformation behavior of BNNSs/Al composite.It is found that the generation of the transition interface can not only weaken the stress partitioning behavior in the elastic stage,but also constrain the crack initiation and propagation behavior in the elastic-plastic stage and plastic stage,thereby improving the deformation compatibility between BNNSs and Al.The present work provides a novel view into the breakthrough for the trade-offrelationship of strength and ductility by coherent transition interface design in nanocomposites.
文摘The interface morphologies and microstruetures of the directionally solidified Ni-5wt-% Cu alloy during dendrite-to-cell transition at high growth rates have been investigated with a newly developed apparatus for unidirectional solidification with the temperature gradient at the solid/liquid interface higher than 1000 K/cm.The results show that in the vicinity of dendrite-to-cell transition point,the well developed sidebranches become shrivelled with the increase of growth rate and disappear at the dendrite-to-cell transition,and the primary spacing decreases simultaneously.Moreover,the length of mushy zone decreases greatly dur- ing the dendrite-to-cell transition.Cells obtained at high growth rates have very similar morphologies to those at low growth rates,but with much smaller cell spacings and unsmoothed cell walls which may be attributed to the different stability conditions of the cell walls at low and high growth rates respectively.
文摘The temperature gradients that arise in the paraelectric-ferroelectric interface dynamics induced by the latent heat transfer are studied from the point of view that a ferroelectric phase transition is a stationary, thermal-electric coupled transport process. The local entropy production is derived for a ferroelectric phase transition system from the Gibbs equation. Three types of regions in the system are described well by using the Onsager relations and the principle of minimum entropy production. The theoretical results coincides with the experimental ones.
基金financially supported by the National Natural Sciences Fund (No.42172128)the National Key Research and Development Program of China (No.2018YFC0604200)the International Geoscience Programme (IGCP-675)
文摘Compared to the sandstone-type uranium deposits in the Ordos Basin and the Songliao Basin,the Tamusu uranium deposit in the Bayingobi Basin formed in fault-depression transition region displays distinctive features.First,the uranium-bearing sandstones and their interlayer oxidation zone extend longitudinally no more than ten kilometers.Second,gravity flow sediments are more common in the uranium-bearing strata.Comprehensive facies analysis indicates that the Upper Member(orebearing horizon)of the Bayingobi Formation was largely deposited in fan deltas that prograded into lakes during period of relatively dry paleoclimate.Spatial distribution patterns of five facies associations along with two depositional environments(fan delta,lake)were reconstructed in this study.The results demonstrated that the depositional systems and their inner genetic facies played different roles in uranium reservoir sandstone,confining beds(isolated barrier beds)and reduction geologic bodies during uranium mineralization process.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11404133 and 11374121)the Program of Science and Technology Development Plan of Jilin Province,China(Grant No.20140520105JH)
文摘Interface and scale effects are the two most important factors which strongly affect the structure and the properties of nano-/micro-crystals under pressure.We conduct an experiment under high pressure in situ alternating current impedance to elucidate the effects of interface on the structure and electrical transport behavior of two Zn Se samples with different sizes obtained by physical grinding.The results show that（i） two different-sized Zn Se samples undergo the same phase transitions from zinc blend to cinnabar-type phase and then to rock salt phase;（ii） the structural transition pressure of the859-nm Zn Se sample is higher than that of the sample of 478 nm,which indicates the strong scale effect.The pressure induced boundary resistance change is obtained by fitting the impedance spectrum,which shows that the boundary conduction dominates the electrical transport behavior of Zn Se in the whole experimental pressure range.By comparing the impedance spectra of two different-sized Zn Se samples at high pressure,we find that the resistance of the 478-nm Zn Se sample is lower than that of the 859-nm sample,which illustrates that the sample with smaller particle size has more defects which are due to physical grinding.
基金supported by the National Natural Science Foundation of China (Grant No.41772333)the National Natural Science Foundation of Shaanxi Province, China (Grant No.2018JQ5124)the New-Star Talents Promotion Project of Science and Technology of Shaanxi Province, China (Grant No.2019KJXX049)。
文摘The sufficient bond between concrete and rock is an important prerequisite to ensure the effect of shotcrete support. However, in cold regions engineering protection system, the bond condition of rock and concrete surface is easily affected by freeze-thaw cycles, resulting in interface damage, debonding and even supporting failure. Understanding the micromechanisms of the damage and debonding of the rock-concrete interface is essential for improving the interface protection.Therefore, the micromorphology, micromechanical properties, and microdebonding evolution of the sandstone-concrete interface transition zone(ITZ) under varying freeze-thaw cycles(0, 5, 10, 15, 20) were studied using scanning electron microscope, stereoscopic microscope, and nano-indentation. Furthermore, the distribution range and evolution process of ITZ affected by freeze-thaw cycles were defined. Major findings of this study are as follows:(1) The microdamage evolution law of the ITZ under increasing freeze-thaw cycles is clarified, and the relationship between the number of cracks in the ITZ and freeze-thaw cycles is established;(2) As the number of freeze-thaw cycles increases, the ITZ's micromechanical strength decreases, and its development width tends to increase;(3) The damage and debonding evolution mechanisms of sandstone-concrete ITZ under freeze-thaw cycles is revealed, and its micromechanical evolution model induced by freeze-thaw cycles is proposed.
基金financial support from the National Key Research and Development Program of China(2017YFB0102900)
文摘Zn-air batteries(ZABs),especially the secondary batteries,have engrossed a great interest because of its high specific energy,economical and high safety.However,due to the insufficient activity and stability of bifunctional electrocatalysts for air-cathode oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)processes,the practical application of rechargeable ZABs is seriously hindered.In the effort of developing high active,stable and cost-effective electrocatalysts,transition metal nitrides(TMNs)have been regarded as the candidates due to their high conductivity,strong corrosion-resistance,and bifunctional catalytic performance.In this paper,the research progress in TMNs-based material as ORR and OER electrocatalysts for ZABs is discussed with respect to their synthesis,chemical/physical characterization,and performance validation/optimization.The surface/interface nanoengineering strategies such as defect engineering,support binding,heteroatom introduction,crystal plane orientation,interface construction and small size effect,the physical and chemical properties of TMNs-based electrocatalysts are emphasized with respect to their structures/morphologies,composition,electrical conductivity,specific surface area,chemical stability and corrosion resistance.The challenges of TMNs-based materials as bifunctional air-cathode electrocatalysts in practical application are evaluated,and numerous research guidelines to solve these problems are put forward for facilitating further research and development.
基金the National Natural Science Foundation of China(Grant No.51976002)the Beijing Nova Program of Science and Technology(Grant No.Z191100001119033)。
文摘Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectification phenomenon in an asymmetric solid–liquid–solid sandwiched system with a nano-structured interface.By using the non-equilibrium molecular dynamics simulations,the thermal transport through the solid–liquid–solid system is examined,and the thermal rectification phenomenon can be observed.It is revealed that the thermal rectification effect can be attributed to the significant difference in the interfacial thermal resistance between Cassie and Wenzel states when reversing the temperature bias.In addition,effects of the liquid density,solid–liquid bonding strength and nanostructure size on the thermal rectification are examined.The findings may provide a new way for designs of certain thermal devices.
基金supported by the National Natural Science Foundation of China(52005361)the Central Science and Technology Research Fund(YDZJSX2022A022)+3 种基金the Postdoctoral Science Foundation of China(2021M692373)the State Key Laboratory of Material Processing and Mold Technology of Huazhong University of Science and Technology(P2022-004)the China Postdoctoral Science Foundation Project(2023T160474)Open Research Fund from the Hai'an&Taiyuan University of Technology Advanced Manufacturing and Intelligent Equipment Industrial Research Institute(2023HA-TYUTKFYF019).
文摘Based on the two-pass differential temperature rolling bonding method,the effects of prefabricated steel/aluminum composite panel temperature on interface characteristics and microstructure properties were investigated through experimental analysis and finite element simulations.When the temperature exceeds 400℃,the effective preparation of the steel-aluminum transition joint can be achieved,and with the increase in temperature,the interface shear and pull-off strength of the steel-aluminum transition joint exhibits an initial decrease followed by an increase.Both the interface shear and pull-off fractures are in 1060 aluminum matrix.As the temperature increases,the size of the average grain in 1060 aluminum matrix increases and then decreases.When the temperature reaches 550℃,the comprehensive performance of the prepared steel-aluminum transition joint is the best,with the interface shear strength of 77 MPa and the interface pull-off strength of 153 MPa,exceeding the bonding strength of the explosive compounding method.There are no pinholes,wrinkles,or cracks in the lateral bending matrix and the interface.
基金the support by National Natural Science Foundation of China(Grant No.62004200)Zhejiang Provincial Natural Science Foundation(Grant No.LZ21F040001)+1 种基金the support by Q-MEEN-Cfunded by the U.S.DOE-BES under award No.DE-SC0019273.
文摘Engineering oxygen vacancy formation and distribution is a powerful route for controlling the oxygen sublattice evolution that affects diverse functional behavior.The controlling of the oxygen vacancy formation process is particularly important for inducing topotactic phase transitions that occur by transformation of the oxygen sublattice.Here we demonstrate an epitaxial nanocomposite approach for exploring the spatial control of topotactic phase transition from a pristine perovskite phase to an oxygen vacancy-ordered brownmillerite(BM)phase in a model oxide La_(0.7)Sr_(0.3)MnO_(3)(LSMO).Incorporating a minority phase NiO in LSMO films creates ultrahigh density of vertically aligned epitaxial interfaces that strongly influence the oxygen vacancy formation and distribution in LSMO.Combined structural characterizations reveal strong interactions between NiO and LSMO across the epitaxial interfaces leading to a topotactic phase transition in LSMO accompanied by significant morphology evolution in NiO.Using the NiO nominal ratio as a single control parameter,we obtain intermediate topotactic nanostructures with distinct distribution of the transformed LSMO-BM phase,which enables systematic tuning of magnetic and electrical transport properties.The use of self-assembled heterostructure interfaces by the epitaxial nanocomposite platform enables more versatile design of topotactic phase structures and correlated functionalities that are sensitive to oxygen vacancies.
文摘Water electrolysis for green hydrogen production is important for the global carbon neutrality.The industrialization of this technology requires efficient and durable electrocatalysts under high-current-density(HCD)operations.However,the insufficient mass and charge transfer at the various interfaces lead to unsatisfactory HCD activity and durability.Interface engineering is important for designing efficient HCD electrocatalysts.In this perspective,we analyze the processes taking place at three interfaces including the catalyst-substrate,catalyst-electrolyte,and catalyst-gas interfaces,and reveal the correlations between interface interactions and the challenges for HCD electrolysis.We then highlight the development of HCD electrocatalysts that focus on interface engineering using the example of transition metal dichalcogenide based catalysts,which have attracted widespread interests in recent years.Finally,we give an outlook on the development of interface engineering for the industrialization of water electrolysis technology.
文摘At present there is no explanation of the nature of interface instability upon first order phase transitions. The well-known theory of concentration overcooling under directed crystallization of solutions and Mullins-Sekerka instability cannot account for the diversified liquid component redistribution during solid state transition. In [1-3], within the framework of the nonequilibrium mass transfer problem, it has been shown that there are regimes of the interface instability, which differ from the known ones [4-6]. Moreover, the instability theory of works [1-3] demonstrates a complete experimental agreement of the dependence of eutectic pattern period on interface velocity. However, it is difficult to explain interface instability within the framework of a general setting of the mass-transfer problem. This paper is de-voted to qualitative analysis of the phenomena that are responsible for interface instability. The phenomena are connected by a single equation. Qualitative analysis revealed a variety of different conditions responsible for instability of flat interface stationary movement upon phase transition. The type of instability depends on system parameters. It is important that interface instability in the asymptotic case of quasi-equilibrium problem setting is qualitatively different from interface instability in the case of nonequilibrium problem setting.
基金financially supported by the National Natural Science Foundation of China-Outstanding Young Scholars(52325407)National Natural Science Foundation of China(52474401)+1 种基金Project funded by China Postdoctoral Science Foundation(No.2022M712919)Guangdong Basic and Applied Basic Research Foundation(2023A1515140124,2025A1515012873,2022A1515140028,2022A1515010761).
文摘The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and Al_(3)Ni brittle intermetallic compounds(IMCs)under different conditions was investigated,and the formation mechanisms of dendritic Al_(3)Ni crystals with different morphologies were elucidated.The increasing remelting cycles accelerated the formation of Al_(3)Ni_(2) layer and the growth of Al_(3)Ni IMCs.The increased-step heating temperatures and time promoted the morphological transition from faceted to non-faceted dendritic Al_(3)Ni,which was attributed to the enhanced undercooling during solidification and incompletely remelted Al_(3)Ni IMCs during remelting.The growth of regular Al_(3)Ni dendrites was dominated by coalescence of secondary dendrite arms,while the growth of irregular dendrites Al_(3)Ni was controlled by dendrite merging,radial melting and axial melting of secondary arms.The axially free dendritic Al_(3)Ni was attributed to the small distance between adjacent main trunks,and the dense secondary arms promoted the formation of local solute depletion regions.
基金financially supported by the National Natural Science Foundation of China(No.52302223)the Fundamental Research Funds for the Central Universities(Nos.2232024G-06-01,24S10102 and 23S10115)
文摘Layered transition metal dichalcogenides(TMDs)have emerged as promising electrode materials for supercapacitors due to their high theoretical specific capacitance,unique layered structure,large surface area,and tunable energy band structure.Substantial progress has been made in the development of TMDs for supercapacitors,with several great breakthroughs reported.However,the practical application of TMDs is still hindered by several challenges,including their susceptibility to oxidation,the tendency to restack or aggregate,structural instability,and interior electrical conductivity.To overcome these limitations,the construction of heterostructures has been identified as an effective strategy.By modulating the interface structure between different components,heterostructures can enhance overall structural stability and facilitate faster ion transport,thereby improving the efficiency of supercapacitors.This review provides a comprehensive overview of recent advances in TMD-based heterostructures for supercapacitors,focusing on their synthesis methods,the relationship between structure,properties,and electrochemical performance,as well as existing challenges.Particular emphasis is placed on hetero structure engineering strategies that integrate TMDs with materials of various dimensionalities(0D,1D,2D,and 3D)to enhance their electrochemical performance for supercapacitors.Finally,the review discusses critical challenges and outlines future perspectives that may guide the development of TMDs for supercapacitors and beyond.
基金Funded by a Chinese-Dutch Cooperation Project "Concrete Composite Technology
文摘The microstructure of ITZ (Interfacial Transition Zone) in single glass fibre-cement was investigated by SEM ( Scanning Electron Microscope), EPXM ( Electron Probe X-ray Microanalyzer) and ESEM (Environmental Scanning Electron Microscope) . The surface morphology of glass fibres and the hydration products in the vicinity of the interfaces were observed. Chemical element (Zr, Ca and Si) distributions over the ITZ thickness were determined by line-scanning with EPXM. The results show that a low-density transition zone existed in the vicinity of glass fibres . The shape of the fibre-cement ITZ was non-symmetrical and its thickness was variable . In the present study, the width of the zone ranged from 1 - 5 μm. Locally, it came to 10μm. Occasionally , some hydration products with high alkalinity were embedded inside the ITZ, and attached on the glass surface , making the ITZ denser and causing local glass to corrode. The test results are helpful for the further understanding of the GRC degradation .
文摘Poly(lactic acid)(PLA)has attracted considerable interest as an environmentally friendly and biodegradable polymer.The properties of poly(L-lactic acid)(PLLA)at an air/water interface were studied based on the Langmuir-Blodgett(LB)film balance and atomic force microscopy(AFM).The surface pressure-area(E-A)isotherm indicated that the surface pressure of PLLA initially increased as the interfacial film was compressed;at Tr=9.0 mN·m^-1,a plateau was observed in the TT--A isotherm,in which the area of the repeat unit was in the approximate range 0.11-0.17 nm^2,The AFM results showed that there is a clear structural transition in the PLLA film during the compression:(i)at the beginning of the plateau,a number of fibrils are present at the air/water interface and(ii)multilayer structures(at least bilayer,i.e.,the underlying layer and top layer consisting of fibrils)is formed in the plateau region.In particular,when Tr=20.0 mN·m^-1,a thin film of PLLA of thickness about 6.0 nm was fabricated.Our findings suggest that the plateau in the PLLA Tr-A isotherm is closely related to a change in the film structure from monolayer to multilayer at the air/water interface.This is significantly different from the behavior of conventional amphiphiles,because the plateau in amphiphiles TT--A isotherm is equivalent to a phase transition of monolayers derived from amphiphiles in a two-dimensional plane.
文摘Tectonic dynamic system transition, one of the main factors in metallogenesis, controls metallogenic fluid movement and ore body location in orefields and on an ore deposit scale (mainly in the continental tectonic setting), and even the formation and distribution of large-scale deposit clusters. Tectonic dynamic system transition can be classified as the spacious difference of the tectonic dynamic system in various geological units and the temporal alteration of different tectonic dynamic systems. The former results in outburst of mineralization, while the latter leads to the metallogenic diversity. Both of them are the main contents of metallogenic effect of tectonic dynamic system transition, that is, the alteration of dynamic system, the occurrence of mineralization, and the difference of regional tectonic dynamic system and metallogenic diversity. Generally speaking, the coupling of spatial difference of tectonic dynamic system and its successive alternation controlled the tempo-spatial evolution regularity of mineralization on a larger scale. In addition, the analysis of mineralization factors and processes of typical ore deposits proved that the changes of tectonic stress field, the direct appearance of tectonic dynamic system transition, may lead to the accident of mineralization physical-chemical field and the corresponding accidental interfaces were always located at ore bodies.
