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Metal‐semiconductor interfaces are crucial components of optoelectronic and electrical devices, the performance of which hinges on intricate dynamics involving charge transport and mechanical interaction at the interface. Nevertheless, structural changes upon photoexcitation and subsequent carrier transportation at the interface, which crucially impact hot carrier stability and lifetime, remain elusive. To address this long‐standing problem, they investigated the electron dynamics and resulting structural changes at the Au/TiO2 interface using ultrafast electron diffraction (UED). The analysis of the UED data reveals that interlayer electron transfer from metal to semiconductor generates a strong coupling between the two layers, offering a new way for ultrafast heat transfer through the interface and leading to a coherent structural vibration that plays a critical role in propagating mechanical stress. These findings provide insights into the relationship between electron transfer and interfacial mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

In order to enhance the hardness and wear resistance of 316L alloy, a strengthening phase was incorporated and laser-directed energy deposition was utilized to create a composite deposition layer consisting of coarse WC/316L, fine WC/316L, and coarse/fine WC/316L. Microstructural observations, phase composition analysis, Vickers hardness testing, interfacial coupling analysis, x-ray diffraction (XRD), and evaluation of friction-wear performance were systematically performed on the deposited samples. These investigations were undertaken to elucidate the impact of incorporating WC particles on both microstructural features and wear characteristics. Results showed that the average grain size of the composite deposition sample with coarse WC/316L decreased by 24% compared to 316L, with a 15.9% increase in hardness and a 97.6% decrease in wear rate. Similarly, the fine WC/316L composite deposition sample saw a 23% reduction in grain size, a 6.4% hardness increase, and a 62.4% decrease in wear rate compared to 316L. The hardness increased by 6.4%. The wear rate decreased by 62.4%. The coarse/fine WC/316L composite deposition samples exhibited a 34% decrease in average grain size, a 35.9% hardness increase, and a 99.1% decrease in wear rate compared to 316L. The addition of WC significantly enhanced the properties of 316L alloy, with coarse/fine WC showing the most significant improvements in microhardness and wear resistance. [ABSTRACT FROM AUTHOR]

Hollow semiconductor nanostructures with direct Z-scheme heterojunction have significant advantages for photocatalytic reactions, and optimizing the interfacial charge transmission of Z-scheme heterojunction is the hinge to achieve excellent solar conversion efficiency. In this work, tubular Ni1-xCoxS2-CdS heterostructures with reinforced Z-scheme charge transmission were constructed through an In-metal-organic framework (MOF) templated strategy. The Z-scheme charge transfer mechanism was sufficiently confirmed by combining density functional theory (DFT) calculation, X-ray photoelectron spectroscopy (XPS), surface photovoltage spectroscopy (SPV), and radical testing results. Crucially, the use of sodium citrate complexant contributes to the formation of intimate heterointerface, and the Fermi level gap between CdS and NiS2 is enlarged through Co doping into NiS2, which enhances the built-in electric field and photo-carriers transmission driving force for Ni1-xCoxS2-CdS heterojunction, resulting in an evidently promoted activity toward H2 evolution reaction (HER). Under visible-light (λ > 400 nm) irradiation, the Ni1-xCoxS2-CdS composite with 10 mol% Co doping and 80 wt.% CdS (NC0.10S-80% CdS) achieved an outstanding HER rate up to 35.94 mmol·g-1·h-1 (corresponding to the apparent quantum efficiency of 34.7% at 420 nm), approximately 76.4 times that of 3 wt.% Pt-loaded CdS and it is much superior to that of most CdS-based photocatalysts ever reported. Moreover, the good photocatalytic durability of Ni1-xCoxS2-CdS heterostructures was validated by cycling and long-term HER tests. This work could inspire the development of high-performance Z-scheme heterojunction via optimizing the morphology and interfacial charge transmission. [ABSTRACT FROM AUTHOR]

In the vast family of two-dimensional (2D) van der Waals materials, 2D magnets have unique advantages in the experimental realization of numerous theoretical works and fundamental exploration of high-performance spintronic devices in the 2D limit. Fe3GeTe2 (FGT), as a typical 2D metallic ferromagnet, is a promising candidate to achieve functional devices at room temperature due to its relatively high Curie temperature (TC) and strong perpendicular magnetic anisotropy (PMA). Here, we investigated self-modulated magnetic properties of FGT nanoflakes in an ambient environment by anomalous Hall effect (AHE). Unique double square-shaped hysteresis loops are observed in oxidized Fe3GeTe2 nanoflakes induced by ambient effects. We propose a phenomenological model based on antiferromagnetic/ferromagnetic coupling in the FGT nanoflakes with oxidized surface layers to elucidate this observation. Compared with a single square-shaped hysteresis loop of well-preserved FGT, double square-shaped hysteresis loops exhibit four-resistance plateaus, which can be regarded as a kind of media for information storage or sensing, showing potential applications in next-generation spintronic devices. [ABSTRACT FROM AUTHOR]

Van der Waals materials and their interfaces play critical roles in defining electrical contacts for nanoelectronics and developing vehicles for mechanoelectrical energy conversion. In this work, we propose a vertical strain engineering approach by enforcing pressure across the heterostructures. First-principles calculations show that the in-plane band structures of 2D materials such as graphene, h-BN, and MoS2 as well as the electronic coupling at their contacts can be significantly modified. For the graphene/h-BN contact, a band gap in graphene is opened, while at the graphene/MoS2 interface, the band gap of MoS2 and the Schottky barrier height at contact diminish. Changes and transitions in the nature of contacts are attributed to localized orbital coupling and analyzed through the redistribution of charge densities, the crystal orbital Hamilton population, and electron localization, which yield consistent measures. These findings offer key insights into the understanding of interfacial interaction between 2D materials as well as the efficiency of electronic transport and energy conversion processes. [ABSTRACT FROM AUTHOR]

The rapid development of digital technology results in a tremendous increase in computational tasks that impose stringent performance requirements on next‐generation computing. Biological neurons with fault tolerance and logic functions exhibit powerful computing capacity when facing complex real‐world problems, which strikes the inspiration for the development of highly energy‐efficient brain‐like computing. Herein, a novel device architecture, an electrolyte‐manipulated ferroelectric organic neuristor, which emulates biological neurons to perform both neuromorphic and reconfigurable logic‐in‐memory operations in a single cell, is proposed. The interfacial coupling of ions and dipoles in the neuristor contributes to the tunable synaptic behaviors of short‐ to long‐term plasticity. Notably, by virtue of lateral capacitive coupling, the neuristor is effectively controlled by multiple in‐plane gates to achieve heterosynaptic plasticity. An artificial neural network exhibits robust recognition ability with high accuracy of 93.7% in speech recognition, further demonstrating the feasibility of the neuristor for neuromorphic computing. Additionally, reconfigurable logic‐in‐memory operations (OR and AND) are successfully demonstrated in a single device. Therefore, the devices shed new light on the development of more brain‐inspired computing systems in the era of big data. [ABSTRACT FROM AUTHOR]

Tin selenide (SnSe2) is considered a promising anode of the lithium‐ion battery because of its tunable interlayer space, abundant active sites, and high theoretical capacity. However, the low electronic conductivity and large volume variation during the charging/discharging processes inevitably result in inadequate specific capacity and inferior cyclic stability. Herein, a high‐throughput wet chemical method to synthesize SnSe2/SnSe heterostructures is designed and used as anodes of lithium‐ion batteries. The hierarchical nanoflower morphology of such heterostructures buffers the volume expansion, while the built‐in electric field and metallic feature increase the charge transport capability. As expected, the superb specific capacity (≈911.4 mAh g−1 at 0.1 A g−1), high‐rate performance, and outstanding cyclic stability are obtained in the lithium‐ion batteries composed of SnSe2/SnSe anodes. More intriguingly, a reversible specific capacity (≈374.7 mAh g−1 at 2.5 A g−1) is maintained after 1000 cycles. The internal lithium storage mechanism is clarified by density functional theory (DFT) calculations and in situ characterizations. This work hereby provides a new paradigm for enhancing lithium‐ion battery performances by constructing heterostructures. [ABSTRACT FROM AUTHOR]

The construction of heterostructures is a versatile tactic to enhance catalytic activity. However, it is still elusive to realize the modulation of the interlayer spacing in this way to further improve the performance. Here, strong interfacial coupling between CoSe2 and MoSe2 by constructing CoSe2/MoSe2 heterostructures is achieved. The interlayer spacing of MoSe2 is compressed by 0.3 Å. The enhanced charge transfer is validated by X‐ray absorption spectroscopy and X‐ray photoelectron spectroscopy. Coupled with the morphology of hollow microtubes, which can facilitate the exposure of active sites, CoSe2/MoSe2 heterostructures reported here exhibit high activity (119 mV at 10 mA cm−2) and excellent stability with small degradation after 50 h operation, surpassing other analogous powdered electrocatalysts. This work sheds light on the importance of tuning the interlayer spacing to improve electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Blending Polyetheretherketone (PEEK) with Polyvinyl alcohol (PVA) is promising to obtain a composite scaffold combining the excellent biomechanical properties of PEEK and the remarkable degradability of PVA. However, the weak interfacial bonding between nonpolar PEEK and polar PVA would result in poor mechanical properties. In this study, owing to its unique amphiphilic properties, graphene oxide (GO) was employed to enhance the interfacial bonding between PEEK and PVA in PEEK/PVA scaffolds that were fabricated by laser 3D printing. On the one hand, the large π-conjugated structure of GO formed strong π-π interactions with the benzene rings in PEEK. On the other hand, the oxygen-containing groups of GO formed strong hydrogen bonds with the hydroxyl groups of PVA. As a result, the interfacial free energy between PEEK and PVA decreased from 37.4 to 29.6 mJ/m2 according to the harmonic-mean rule, and the PVA phase in PEEK matrix became much fine and uniform, indicating a reinforced interfacial bonding. Correspondingly, the strength and modulus of PEEK/PVA scaffolds increased by 97.16% and 147.06%, respectively, for a GO loading of 1%. Furthermore, the scaffolds exhibited good hydrophilicity and degradability, and promoted cell attachment and proliferation in vitro and osteogenic differentiation and bone regeneration in vivo. [ABSTRACT FROM AUTHOR]

Developing high activity, strong durability, and cost-efficient electrocatalysts for the hydrogen evolution reaction (HER) is critical for the sustainable production of hydrogen energy. Herein, we have rationally designed three-dimensional (3D) heterogeneous catalyst of hollow nickel phosphide spheres coupled with molybdenum sulfide nanosheets (Ni2P@MoS2). Benefiting from the hollow spherical structure and the coupling effects between MoS2 and Ni2P, Ni2P@MoS2 shows superior activity for hydrogen generation over a wide pH range. It displays overpotentials of 181, 269 and 535 mV in 1.0 M KOH, 0.5 M H2SO4 and 1.0 M PBS, respectively, at a current density of 10 mAcm-2. A series of characterization techniques demonstrate that the strong coupling interaction between Ni2P and MoS2 effectively optimizes the electronic structure of the Ni2PMoS2 3D/2D interfaces, beneficial for regulating H* adsorption energy. This work offers a novel strategy for enhancing the HER performance of metal phosphide/sulfide catalysts by constructing heterostructured materials with abundant 3D/2D interfaces. [ABSTRACT FROM AUTHOR]

We have demonstrated the improved performance of oxygen evolution reactions (OER) using Au/nickel phosphide (NiP) core/shell nanoparticles (NPs) under basic conditions. NPs with a NiP shell and a Au core, both of which have well-defined crystal structures, have been prepared using solution-based synthetic routes. Compared with pure NiP NPs and Au-NiP oligomer-like NPs, the core/shell crystalline structure with Au shows an improved OER activity. It affords a current density of 10 mA/cm at a small overpotential of 0.34 V, in 1 M KOH aqueous solution at room temperature. This enhanced OER activity may relate to the strong structural and effective electronic coupling between the single-crystal core and the shell. [ABSTRACT FROM AUTHOR]

The flow of an upper shear-driven Newtonian fluid above an otherwise still non-Newtonian fluid is considered. The lower fluid is modelled as a generalized Newtonian fluid and set into motion by interfacial shear. By means of similarity transformations, the governing partial differential equations for the two-fluid problem transform exactly into two sets of ordinary differential equations coupled only at the interface. The successful transformation of the two-fluid problem is applied to the particular case when the lower fluid obeys power-law rheology. The resulting three-parameter problem is solved numerically for some different parameter combinations by means of a direct integration approach with the density ratio fixed to unity. We observed that the interfacial velocities decreased with increasing values of the power-law index n in the range from 0.6 to 1.4 whereas the shear-induced motion of the lower fluid penetrates far deeper into a shear-thinning ( n < 1) than into a shear-thickening ( n > 1) fluid. This phenomenon is ascribed to a corresponding increase of the non-linear viscosity function with lower n-values. [ABSTRACT FROM AUTHOR]

This paper deals with the non-conservative coupling of two one-dimensional barotropic Euler systems at an interface at x = 0. The closure pressure laws differ in the domains x < 0 and x > 0, and a Dirac source term concentrated at x = 0 models singular pressure losses. We propose two numerical methods. The first one relies on ghost state reconstructions at the interface while the second is based on a suitable relaxation framework. Both methods satisfy a well-balanced property for stationary solutions. In addition, the second method preserves mass conservation and exactly restores the prescribed singular pressure drops for both unsteady and steady solutions. [ABSTRACT FROM AUTHOR]

Dynamic spontaneous imbibition (DSI) plays an important role in oil reservoir characterization. Conventional equations used to characterize DSI consider neither interfacial coupling effects (ICE) nor variable inlet saturation ( S*) for DSI. Yazzan et al. (Transp Porous Media 87(1):309-333, ; 86(3):705-717, ) developed a set of equations, and a numerical solution scheme, to take into account ICE and variable S* for DSI. Based on these, a graphical user interface (GUI) simulator was built. A sensitivity analysis has been conducted to study the effect of the fluid and rock properties on DSI. The results reveal that including a variable S* has no significant impact; however, neglecting ICE results in an overestimation of the imbibition flow rate. Moreover, it is shown that the capillary and relative permeability curves determine the type of frontal advance, and that the imbibition recovery is proportional to the square root of time. [ABSTRACT FROM AUTHOR]

In the oil industry, dynamic spontaneous imbibition plays an important role in several flow processes in porous media. A numerical approach is developed to simulate dynamic spontaneous imbibition with variable inlet saturation and interfacial coupling. The inclusion of interfacial coupling effects invalidates the assumption that the interfaces (fluid/fluid and fluid/solid) act in the same way. The one-dimensional numerical simulation model is developed using a Lagrangian formulation discretized in time and saturation. The solution of the partial differential equations utilizes an iteration process that includes two material balance criteria to ensure the validity of the variable inlet saturation. Furthermore, an error analysis, the validation of the model and a sensitivity study on the optimal number of time steps and saturation grid cells are undertaken. The numerical simulation solution represents an accurate approach to investigate the effect of fluid and rock properties on dynamic spontaneous imbibition. [ABSTRACT FROM AUTHOR]

In oil recovery from fractured reservoirs, dynamic spontaneous imbibition (DSI) plays an important role. Conventional equations used for characterizing dynamic spontaneous imbibition neglect the effects of the driving forces acting across the wetting and non-wetting phases which are flowing in opposite directions. Such effects, defined as interfacial coupling effects (ICE), are known to cause a decrease in the calculated flow rate in drainage processes. Moreover, none of the numerical models have considered a variable inlet saturation ( S*) for DSI. A new theoretical model has been developed using generalized transport equations to describe dynamic spontaneous imbibition for immiscible two-phase flow processes. The inclusion of interfacial coupling effects provides a more accurate way to describe dynamic spontaneous imbibition. Furthermore, the addition of variable inlet saturation allows one to establish whether the inlet-face saturation ( S*) increases from the initial saturation to 1−Sro, or whether it can remain constant and equal to one minus the residual saturation to the non-wetting phase (1−Sro). [ABSTRACT FROM AUTHOR]

We report on the enhancement of the exchange field, H[subEX], in IrMn/CoFe systems as a result of the application of field annealing procedures. The exchange field is enhanced up to a 37% on application of a 2 Tesla field for 90 minutes at 225°C. This setting process improves the magnitude of H[subEX] without significant changes in the coercivity, H[subC],or the median blocking temperature. The sample with largest exchange bias field measured, 3.7 kOe and H[subC] = 0.2 kOe at 20° C, seems to have the largest ratio of H[subEX] to H[subC] ever reported for an IrMn/CoFe exchange bias system. This makes these structures good candidates as pinned layers in magnetic tunnel junctions. The samples show good thermal stability with median blocking temperatures up to 200°C. The results also indicate that the improvement in the quality of the interfaces via the degree of alignment of the interfacial spins improves the coupling across the interface and hence the magnitude of the exchange bias field. [ABSTRACT FROM AUTHOR]

Two-phase flow through natural porous media is affected by the interfacial coupling that takes place across the interfaces located in a porous medium. Such coupling may be of two types: viscous and capillary. In this study, defining equations for the capillary and viscous coupling parameters have been constructed. Moreover, these equations, together with a modified form of Kalaydjian's transport equations, have been used to analyze interfacial coupling in two-phase flow through porous media. On the basis of the analysis carried out, it is argued that interfacial coupling has no effect on steady-state, cocurrent flow, and only a small effect on unsteady-state, cocurrent flow. Moreover, it is suggested that interfacial coupling has a significant effect on steady-state, countercurrent How, Two methods were used to test the theory. In the first method, data from steady-state, cocurrent, and countercurrent experiments were used to show that experimentally determined values of the capillary coupling parameters were in good agreement with those predicted theoretically. Because of experimental problems, it was not possible to determine experimentally, when using the first method, the magnitude of the viscous coupling parameters. In the second method, data from steady-stale and unsteady-state, cocurrent flow experiments, using fluids having different viscosity ratios, and porous media having different grain-size distributions, were used to test the theory. Because of a lack of sufficient precision in the measured data, it was not possible to make definitive statements with respect to the adequacy of the theory, or the possible impact of viscosity ratio and grain-size distribution on capillary coupling. Moreover, for the same reason, it was not possible to obtain reliable estimates of the magnitude of the capillary coupling parameters. Because the second method is based on the assumption that viscous coupling is negligible, it was not possible to use this method to determine experimentally the magnitude of the viscous coupling parameters. [ABSTRACT FROM AUTHOR]

This paper provides details of the numerical simulation process for the interfacial coupling effect in multiphase flow through porous media. It covers the theoretical background, description of mathematical formulations, basic assumptions in the models, normalization and transformation between Lagrangian and Eulerian formulations, specification of boundary conditions, discretization and grid system, and solution methods. The main advantage of the Lagrangian formalism is that it eliminates the need for space discretization thereby reducing computation time and error. The numerical simulation process was codified into a stand-alone numerical simulator using the JavaTM Programming language. Numerical examples obtained from the numerical simulator are presented to show the applicability of the computational technique and to investigate the effects of interfacial coupling and hydrodynamic effects. Numerical results show that interfacial coupling (viscous and capillary) and hydrodynamic effects are insignificant in two-phase, cocurrent, horizontal, porous media flow. Sensitivity analyses studies carried out with the simulator show that if the viscous factor in the parameter that control the amount of viscous coupling is taken as the theoretically established value of 2 or below, then the viscous coupling effect is insignificant. Otherwise, the viscous coupling effect would have a greater effect on the physics of flow and might lead to unreasonable results. [ABSTRACT FROM AUTHOR]

Copolymers which are synthesized by oligomers or homopolymers have quasi-one-dimensional structures. A tight-binding model was suggested to study the organic quantum-well properties of triblock copolymers xPA/nPPP/yPA and xPPP/nPA/yPPP consisting of polyacetylene (PA) and poly( p-phenylene) (PPP). It was found that the electronic density in the lowest conductive state (LUMO) could be tuned by the ratios of homopolymers and interfacial coupling. The spontaneous quantum tunneling effects will occur in triblock copolymer xPA/nPPP/yPA with the increasing interfacial coupling. [ABSTRACT FROM AUTHOR]

A tight-binding model describing the xPPP/yPA diblock copolymer has been adopted. The ground states, doping states, configurations, electronic distributions and the types of excitations have been studied. It is found that the ratios and interfacial couplings of the components have effect on the properties of excitations in xPPP/yPA diblock copolymers. The interface between two homopolymers acts as an energy barrier which increases with the weakening of the interfacial coupling. [ABSTRACT FROM AUTHOR]

Recently developed transport equations for two-phase flow through porous media usually have a second term that has been included to account properly for interfacial coupling between the two flowing phases. The source and magnitude of such coupling is not well understood. In this study, a partition concept has been introduced into Kalaydjian's transport equations to construct modified transport equations that enable a better understanding of the role of interfacial coupling in two-phase flow through natural porous media. Using these equations, it is demonstrated that, in natural porous media, the physical origin of interfacial coupling is the capillarity of the porous medium, and not interfacial momentum transfer, as is usually assumed. The new equations are also used to show that, under conditions of steady-state flow, the magnitude of mobilities measured in a countercurrent flow experiment is the same as that measured in a cocurrent flow experiment, contrary to what has been reported previously. Moreover, the new equations are used to explicate the mechanism by which a saturation front steepens in an unstabilized displacement, and to show that the rate at which a wetting fluid is imbibed into a porous medium is controlled by the capillary coupling parameter, α. Finally, it is argued that the capillary coupling parameter, α, is dependent, at least in part, on porosity. Because a clear understanding of the role played by interfacial coupling is important to an improved understanding of two-phase flow through porous media, the new transport equations should prove to be effective tools for the study of such flow. [ABSTRACT FROM AUTHOR]

Here, crystal structure, electronic structure, chemical substitution, pressure-dependent superconductivity, and thickness-dependent properties in FeSe-based superconductors are systemically reviewed. First, the superconductivity versus chemical substitution is reviewed, where the doping at Fe or Se sites induces different effects on the superconducting critical temperature (Tc). Meanwhile, the application of high pressure is extremely effective in enhancing Tc and simultaneously induces magnetism. Second, the intercalated-FeSe superconductors exhibit higher Tc from 30 to 46 K. Such an enhancement is mainly caused by the charge transfer from the intercalated organic and inorganic layer. Finally, the highest Tc emerging in single-unit-cell FeSe on the SrTiO3 substrate is discussed, where electron-phonon coupling between FeSe and the substrate could enhance Tc to as high as 65 K or 100 K. The step-wise increment of Tc indicates that the synergic effect of carrier doping and electron-phonon coupling plays a critical role in tuning the electronic structure and superconductivity in FeSe-based superconductors. [ABSTRACT FROM AUTHOR]