Coupling Interface Research Articles

Robust and hydrophilic Mo-NiS@NiTe core-shell heterostructure nanorod arrays for efficient hydrogen evolution reaction in alkaline freshwater and seawater

Typically, the direct electrolysis of alkaline seawater for hydrogen production is very attractive, but it poses challenges due to the high energy barrier and slow reaction kinetics of the hydrogen evolution reaction (HER) in alkaline environments. The key to promising solutions lies in the design and development of non-precious metal catalysts with abundant reaction sites, robust stability, and resistance to Cl− corrosion. Hence, we demonstrated the fabrication of Mo-NiS@NiTe core–shell heterogeneous nanorods supported on nickel foam (Mo-NiS@NiTe/NF). These hydrophilic self-supporting nanorod arrays, functioning as binder-free HER electrocatalysts, provide numerous reactive sites and facilitate electron/mass transfer. The conductive core of NiTe promotes rapid electron transfer from NF substrate to NiS. The coupling interface with the heteroatom Mo synergistically modulates the electronic structure of the NiS shell, optimizing the adsorption/dissociation of H2O and improving the reaction kinetics. As a result, Mo-NiS@NiTe/NF exhibits excellent HER performance and outstanding long-term stability, requiring only 34 and 57 mV of overpotential to achieve a current density of 10 mA cm−2 in 1.0 M KOH and alkaline seawater, respectively. Additionally, it exhibits a Faraday efficiency of nearly 100% for hydrogen production and excellent long-cycle stability. Notably, the Mo-NiS@NiTe(−)||RuO2(+) couples outperform Pt/C(−)||RuO2(+) couples and exhibit excellent stability.

Interplay between VSD, pore and membrane lipids in electromechanical coupling in HCN channels.

Hyperpolarized-activated and Cyclic Nucleotide-gated (HCN) channels are the only members of the voltage-gated ion channel superfamily in mammals that open upon hyperpolarization, conferring them pacemaker properties that are instrumental for rhythmic firing of cardiac and neuronal cells. Activation of their voltage-sensor domains (VSD) upon hyperpolarization occurs through a downward movement of the S4 helix bearing the gating charges, which triggers a break in the alpha-helical hydrogen bonding pattern at the level of a conserved Serine residue. Previous structural and molecular simulation studies had however failed to capture pore opening that should be triggered by VSD activation, presumably because of a low VSD/pore electromechanical coupling efficiency and the limited timescales accessible to such techniques. Here, we have used advanced modeling strategies, including enhanced sampling molecular dynamics simulations exploiting comparisons between non-domain swapped voltage-gated ion channel structures trapped in closed and open states to trigger pore gating and characterize electromechanical coupling in HCN1. We propose that the coupling mechanism involves the reorganization of the interfaces between the VSD helices, in particular S4, and the pore-forming helices S5 and S6, subtly shifting the balance between hydrophobic and hydrophilic interactions in a 'domino effect' during activation and gating in this region. Remarkably, our simulations reveal state-dependent occupancy of lipid molecules at this emergent coupling interface, suggesting a key role of lipids in hyperpolarization-dependent gating. Our model provides a rationale for previous observations and a possible mechanism for regulation of HCN channels by the lipidic components of the membrane.

Layered double hydroxides as a robust catalyst for water oxidation through strong substrate-catalytic layer interaction

Electrochemical preparation of hydrogen permits a way to meet our energy and environmental issues, but the anodic reaction is kinetically slow and thus is the bottleneck in the overall water splitting. Achieving cost-effective electrocatalysts represents a big challenge for practical water oxidation. Herein, We report the tuning of the local electron structure of nickel-iron layered double hydroxides (NiFe LDH) by achieving a highly coupled interface between active sites and the current collector. Our developed NiFe-LDH/Fe catalysts as the anode can provide 10 mA cm−2 at 1.455 V vs. RHE with a Tafel slope of only 32.7 mV dec−1. Simultaneously, the catalyst has high catalytic stability. Combined with the X-ray photoelectron spectroscopy and density functional theory calculation, the coupling interface between the substrate and catalytic layer can effectively regulate the electron density of the Fe sites, which is the main reason for the high catalytic ability of the layered double hydroxide catalyst.

2D/2D Z-scheme photocatalyst of g-C3N4 and plasmonic Bi metal deposited Bi2WO6: Enhanced separation and migration of photoinduced charges

An ideal photocatalyst should have high redox capacity, efficient charge separation, and large reaction surface area. However, it is an extreme challenge to construct a photocatalytic system with above three merits. Herein, the g-C3N4/[email protected]2WO6 composite photocatalyst was prepared by simple wet chemical method. Then the separation pathway of photoinduced charges through the interface was explored by XPS, EPR and active species capture experiments, confirming that the Z-scheme charge transfer route was followed. The optimized composite photocatalyst exhibited the photocatalytic hydrogen production rate of 1219.3 μmol h−1g−1, which is 2.29 times that of pure g-C3N4 (533.4 μmol h−1g−1). Moreover, the photocatalytic degradation rates of RhB and TC were 82.43% and 66.7%, respectively, which were 7.55 times and 1.92 times that of pure Bi2WO6. Ultimately, the enhanced photocatalytic performances were attributed to the synergistic effect of 2D/2D coupling interface and the deposited metal Bi, which not only benefited the efficient charge separation and fast charge migration but also provided the large reaction surface area. In addition, surface plasmon resonance effect of metal Bi can boost the visible light absorption and broaden the light absorption range to the full spectrum. Our study provides a new idea to design high-performance Z-scheme photocatalyst for highly efficient utilization of solar energy.

Self-Decoupled Dual-Frequency Patch Antennas via Hybrid Coupling Interface Technique

This letter presents a novel hybrid coupling interface (HCI) technique to achieve self-decoupling between two dual-frequency patch antennas (DFPAs) for the first time, with no need to introduce external structures. To this end, a decoupling condition based on a detailed network analysis indicates the key to realizing self-decoupling at two operating frequencies simultaneously is that the DFPA must have two independent CIs, which is different from the single-band self-decoupling achieved by using mixed coupling in a single CI. Then, an actual DFPA with HCI, composed of a rectangular patch and a short-circuited <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> /4 microstrip resonator, is proposed and constructed in a two-element array with another one, which demonstrates that decoupling can be realized by adjusting the radius of the shorting pin conveniently. Finally, experimental results show that the in-band isolation between two antennas can be enhanced beyond 15 dB across two operating frequency ranges of 3.77 ∼ 3.94 GHz (4.4%) and 4.59 ∼ 4.72 GHz (2.8%).

Topological rainbow based on coupling of topological waveguide and cavity.

Topological photonics and topological photonic states have opened up a new frontier for optical manipulation and robust light trapping. The topological rainbow can separate different frequencies of topological states into different positions. This work combines a topological photonic crystal waveguide (topological PCW) with the optical cavity. The dipole and quadrupole topological rainbows are realized through increasing cavity size along the coupling interface. The flatted band can be obtained by increasing cavity length due to interaction strength between the optical field and defected region material which is extensively promoted. The light propagation through the coupling interface is built on the evanescent overlapping mode tails of the localized fields between bordering cavities. Thus, the ultra-low group velocity is realized at a cavity length more than the lattice constant, which is appropriate for realizing an accurate and precise topological rainbow. Hence, this is a novel release for strong localization with robust transmission and owns the possibility to realize high-performance optical storage devices.

Coupling Design and Validation Analysis of an Integrated Framework of Uncertainty Quantification

The uncertainty quantification is an indispensable part for the validation of the nuclear safety best-estimate codes. However, the uncertainty quantification usually requires the combination of statistical analysis software and nuclear reactor professional codes, and it consumes huge computing resources. In this paper, a design method of coupling interface between DAKOTA Version 6.16 statistical software and nuclear reactor professional simulation codes is proposed, and the integrated computing workflow including interface pre-processing, code batching operations, and interface post-processing can be realized. On this basis, an integrated framework of uncertainty quantification is developed, which is characterized by visualization, convenience, and efficient computing. Meanwhile, a typical example of small-break LOCA analysis of the LOBI test facility was used to validate the reliability of the developed integrated framework of uncertainty quantification. This research work can provide valuable guidance for developing an autonomous uncertainty analysis platform in China.

Review on fluid-structure interaction problem modeling and recent developments

The fluid-structure interaction (FSI) problem plays significant roles in engineering simulations and design. This problem considers the interaction between the fluid domain and structural domain with one-way or two-way data transfer. There are several algorithms to solve the problem, mainly numerical duo to the complexity and nonlinearly. The numerical schemes focus on the modeling method of the coupling interface. However, there are several algorithms that merge the interface in the equations and deal with the domains as a unified set of equations. Future development could include artificial intelligence modeling and the inclusion of more physical domains into the systems.

Unified integral transform solution for vibration analysis of ribbed plate

This paper presents a unified integral transform solution for the analysis of free and forced vibration of ribbed rectangular plate with arbitrary classical boundary conditions, whereas previous integral transform techniques have mainly focused on the analysis of the mechanical behavior of bare plates. The one- and two-dimensional integral transform techniques are applied to the higher-order partial differential governing equations of the beams and the plates, respectively, which are transformed into a system of linear algebraic equations after a rigorous derivation. The unknown coupling force and moment are determined by the compatibility conditions at the beam-plate coupling interface to obtain a unified solution scheme for ribbed plates with arbitrary classical boundary conditions. Good agreements are found between the results of analytical solution, finite element analysis and literature. Moreover, experiments on vibration analysis of a ribbed plate with completely free boundary conditions are conducted to further verify the validity and accuracy of the unified solution scheme. The effect of rib on the vibration response of rectangular plates is also investigated. It is shown that the vibration is controlled by the plate stiffness when the rib plays as a mass loading. The proposed unified analytical solution can be widely used to provide theoretical guidance for the vibration prediction of various structures with ribbed plates, such as offshore platforms, high-speed carriages, and aircraft wings.

A Coupled Heat Transfer Calculation Strategy for Composite Cooling Liquid Rocket Engine

To better understand the characteristics of coupled heat transfer in liquid rocket engines, a calculation scheme is proposed in this paper. This scheme can simulate the coupled heat transfer processes, including combustion and flow in the thrust chamber, radiation heat transfer, heat conduction in the wall, heat transfer of coolant flow in the cooling channel, and gas film cooling in the thrust chamber wall. The numerical method used in each physical area, the data transfer method between each computing module, the strategy of data transfer on the coupling interface, the calculation process, and the convergence criterion are all introduced in detail. The calculation scheme was verified by analyzing a water-cooled nozzle. Then, the coupled heat transfer calculation was carried out for a liquid rocket engine using a propellant composed of unsymmetrical dimethylhydrazine and dinitrogen tetroxide. Two working conditions were analyzed: whether the gas film cooling was performed or not. The results showed that the algorithm successfully indicated the protective effect of the gas film on the wall surface, and the calculation results were reasonable. It played a guiding role for the coupled heat transfer of the liquid rocket engine using a composite cooling method.

Surface-bulk-passivated perovskite films via 2-thiophenemethylammonium bromide and PbBr2 for air-processed perovskite solar cells with high-stability

Suppressing non-radiative recombination induced by defect is of much concern to efficient and stable perovskite solar cells (PSCs). We report a cooperative strategy to passivate both interfacial and bulk defects in perovskite layer by coupling interface engineering and additive engineering. 2-Thiophenemethylammonium bromide (2-ThMAB) is synthesized by recrystallization. PbBr2 used as an additive is introduced into the perovskite precursor solution. 2-ThMAB features with an electron-rich π-system and 2-thiophene group. Br− ions have an impact on perovskite lattice reorganization. The synergistic modification of 2-ThMAB and PbBr2 enables the external electronic state modulation and internal bandgap adjustment of perovskite, which is beneficial to passivate defect and inhibit ion migration. As a result, a modified PSC exhibits a high-power conversion efficiency of 20.01% with negligible hysteresis for an all-air-processed device. More importantly, a non-encapsulated device exhibits excellent long-term stability of T98 of > 720 h. This study thus provides a new way to obtain highly stable all-air-processed PSCs..

A Compressible, Coupled Three-Dimensional/One-Dimensional Flow Solution Method for the Seamless Simulation of Centrifugal Pumps and Their Piping

Abstract A compressible finite volume Navier–Stokes flow solver is coupled to a method of characteristics for the seamless turbulent flow simulation of entire pump systems. For the pump, three-dimensional (3D) simulations including cavitating flow conditions are performed, and the piping is treated one-dimensional (1D) by a method of characteristics. Thus, classical boundary conditions at the suction and pressure pipe of the 3D computational domain of the pump are substituted by a two-way coupled 1D piping simulation method. Particular emphasis has been placed on the non-reflecting properties of the 3D–1D coupling interface. For validation, in-house experiments are performed on a low specific speed centrifugal pump in a closed-loop facility. For cavitating flow conditions, excitation on the pump's pressure side by rotor–stator interaction is enhanced over a broad frequency spectrum due to collapsing voids. The suction side piping is shielded by void regions within the blading from the excitation on the pump's pressure side, leading to an acoustic decoupling of the suction side. These experimental observations are reproduced by the new seamless simulation method. In particular, the measured pressure amplitudes are well reproduced for a broad frequency spectrum, at several piping positions, and for a variation of the flow rate and the cavitation intensity. Remaining deviations to experimental data are traced back to the omission of structural compliance and uncertainties regarding the pressure side piping modeling, which will be addressed in future studies.

A new fluid-structure coupling model: Case of a pipe under internal pressure

This work presents the eigenfrequencies of a study on the fluid-structure interaction for a pipe with a circular section, under pressure constraints in laminar, incompressible and irrotational flow, followed by a comparison between stiffness coupling and bar coupling with different geometric ratio Radius/Length; Radius/Thickness, as a frequency geometric identity of the pipe in the industry. The realization of this study is to have better coupling, where we use the relations of mechanical behaviour of the solid on displacement-stress and for the fluid, we use the Navier-Stokes equations in cylindrical coordinates under the speed-stress form transformed into displacement by the Galerkin-Temp theory. Either the force of the fluid will be distributed on the internal surface of the cylinder by the coupling (interface) between fluid and solid. To obtain the results of the eigenfrequencies we used the hierarchical finite element method (HFEM) for both mechanical and fluid entities. For the natural frequencies, we apply the hierarchical finite elements of the Legendre polynomial which is defined in a well-known interval, thanks to this mathematical calculation we arrive at the general equations of motion matrix form of the solid, the interface and the fluid. The calculation was carried out by a MATLAB programme which determines the eigenfrequencies of the evolved system by different geometric and physical parameters mentioned. We validated this work by a table of comparison between the experimental values and the values of the programme.

Starch-based porous carbon microsphere composited NiCo2O4 nanoflower as bifunctional electrocatalyst for zinc-air battery

It is significant to explore and design outstanding bifunctional oxygen electrocatalysts to promote the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in zinc–air batteries. Herein, a novel porous carbon microspheres (CMS2) modified by NiCo2O4 nanoflower (CMS2–NiCo2O4) have been prepared as an ORR and OER catalyst. The hierarchical porous structure of CMS provides high conductivity and abundant active sites for ORR, whereas the synergistic effect of NiCo2O4 nanosheets and a small amount of FeZn oxides act as the positive phase for OER. The efficient oxygen catalytic activity is gained by creating a coupling interface between NiCo2O4 and CMS. The optimized CMS2–NiCo2O4 shows a half–wave potential of 0.82 V toward ORR and an overpotential of 392 mV toward OER. Particularly, CMS2–NiCo2O4 also exhibits an excellent peak power density (175.5 mW cm−2) as a catalyst for zinc–air batteries, which is superior to the commercial Pt/C + RuO2 catalyst (120.5 mW cm−2), and it also demonstrates a remarkable stability even after the charge–discharge cycles of 167 h. The prepared CMS2–NiCo2O4 is promising for the application of the bimetallic oxide catalyst for zinc–air battery.

Light-Driven Fuel Cell with a 2D/3D Hierarchical CuS@MnS Z-Scheme Catalyst for H2O2 Generation

A photoelectrocatalytic (PEC) oxygen reduction reaction (ORR) strategy with fuel-efficient and cost-effective catalysts for on-demand hydrogen peroxide (H2O2) production is booming as an attractive alternative to the conventional anthraquinone process. Herein, we constructed a novel two-dimensional (2D)/three-dimensional (3D) hierarchical CuS@MnS p-p Z-scheme catalyst with full spectrum absorption and strong coupling interface by regulating the crystal structure, morphology, and photocharge transfer mechanism, which was used as a photocathode for PEC synthesis of H2O2 with a yield of 1.65 mM within 180 min. Taking advantage of a coupling strategy with Sn3O4/Ni foam, the as-prepared two-compartment cell with water oxidation reaction and ORR exhibited boosted activity and stability for the dual production of H2O2. An energy-saving H2O2 generation system was also constructed with a direct hydrazine/O2 fuel cell, realizing the significant advantage in reducing electricity consumption during the H2O2 synthesis. Moreover, the onsite generation of H2O2 remarkably accelerated the degradation of pollutants via a cascade heterogeneous Fenton reaction with a Fe anode. This work provides a new strategy for designing a multifunctional PEC system for the production of high-value chemicals, energy recovery, and pollutant degradation.

A hybrid lattice Boltzmann - Navier-Stokes method for unsteady aerodynamic and aeroacoustic computations

A hybrid numerical method coupling the standard lattice Boltzmann method and a compressible finite-volume Navier-Stokes solver is proposed in the context of unsteady aerodynamic and aeroacoustic simulations. The trend being towards more realistic and detailed simulations in a reasonable amount of CPU time, lattice Boltzmann and Navier-Sokes methods can be combined to solve the same problem. The present hybrid method relies on a zonal decomposition of the computational domain thus allowing to exploit the numerical features of both methods to their optimal extent in specific flow regions.The key issue when combining the lattice Boltzmann method with a Navier-Stokes solver is to ensure a smooth transition of the flow variables at the two-way coupling interface. While existing approaches consider overlapping meshes, a direct grid coupling is here derived. The mapping from the macroscopic flow variables to the set of lattice Boltzmann distribution functions is performed analytically thanks to a Chapman-Enskog expansion and draws a direct link to advanced regularised collision operators. Unsteady computations are enabled by coupling the lattice Boltzmann stream and collide algorithm with explicit and implicit Navier-Stokes time-stepping schemes. The hybrid method is then assessed on four time-dependent test cases representative of aerodynamic and aeroacoustic problems. The proposed approach is proven to yield very accurate results while keeping the numerical advantages of both methods and reducing the overall computational cost of direct noise computations.

Phenyl-Terminated Coupling Interface Enabled Highly Efficient and Stable Multiwavelength Perovskite Single Crystal/Silicon Integrated Photodetector.

The use of amino-terminated siloxanes as coupling interface for perovskite single crystals (PSCs)/silicon integrated devices has been demonstrated to be an effective method toward CMOS compatible optoelectronics; however, it suffers from the coupling stability against the hydrophilicity of the exposed terminal amino groups. In this work, a phenyl-terminated interfacial molecule, anilino-methyl-triethoxysilane (AMTES), is proposed to achieve the effectively galvanic coupling between PSCs and silicon, which can not only improve the device environmental reliability but also lower the surface energy of the silicon substrate so as to facilitate the epitaxial growth of PSCs. Benefiting from the interfacial coupling of AMTES, the obtained MAPbI3 SC/silicon integrated device possesses highly efficient multiwavelength photodetection properties across the X-ray and NIR range, which exhibits a specific detectivity D* of 3.84 × 1013 cm Hz1/2 W-1 in the visible-NIR region and an X-ray sensitivity of 1.18 × 104 μC Gyair-1 cm-2 with the lowest detection limit of 49.6 nGyair s-1. The ultra wide -3 dB bandwidth of 67,300 Hz and the linear dynamic range (LDR) of 112 dB also prove its impressive dynamic response capabilities. Moreover, the AMTES modified integrated device almost maintains 96% of the initial photodetection performance even after keeping in the atmosphere environment for 28 days. This work opens a new avenue for interfacial engineering toward the development of on-chip PSC integrated silicon optoelectronic devices.

Highly Sensitive Artificial Skin Perception Enabled by a Bio-inspired Interface.

Piezoionic strain sensors have attracted enormous attention in artificial skin perception because of high sensitivity, lightweight, and flexibility. However, their sensing properties are limited by a weak material interface based on physical adhesion, which usually leads to fast performance deterioration under mechanical conditions. In this work, a bio-inspired interface has been reported based on an in situ growth strategy and then utilized for piezoionic sensor assembly. The robust coupling interface provides fast kinetic of ion transfer and prevents interface slippage under external strains. The as-fabricated sensors give high sensing voltage with high sensitivity. It delivers excellent cycling stability with performance retention above 90% over thousands of bending cycles in air. Further, the sensors have been explored as an effective platform for skin perception, and many detections can be realized within our devices, such as skin touch, eye movement, cheek bulging, and finger movement.

Crystalline-Amorphous Interface Coupling of Ni3S2/NiPx/NF with Enhanced Activity and Stability for Electrocatalytic Oxygen Evolution.

The rational design of highly efficient and stable electrocatalysts for the oxygen evolution reaction (OER) is an urgent need but remains challenging for various sustainable energy systems. How to adjust the atomic structure and electronic structure of the active center is a key bottleneck problem. Accelerating the electron transfer process and the deep self-reconstruction of active sites could be a cost-effective strategy toward electrocatalytic OER catalyst development. Here, a crystalline-amorphous (c-a) coupled Ni3S2/NiPx electrocatalyst self-supported on nickel foam with an intimate interface was developed via a feasible solvothermal-electrochemistry method. The coupling interface of the crystalline structure with high conductivity and amorphous structure with numerous potential active sites could regulate the electronic structure and optimize the adsorption/desorption of O-containing species, ultimately resulting in high OER catalytic performance. The obtained Ni3S2/NiPx/NF presents a low OER overpotential of 265 mV to obtain 10 mA·cm-2 and a small Tafel slope of 51.6 mV·dec-1. Also, the catalyst with the coupled interface exhibited significantly enhanced long-term stability compared to the other two catalysts, with <5% decay in OER activity over 20 h of continuous operation, while that of Ni3S2/NF and NiPx/NF decreased by about 30 and 50%, respectively. This study provides inspiration for other energy conversion reactions in optimizing the performance of catalysts by coupling crystalline-amorphous structures.

A 1-D/3-D coupling approach for compressible non-equilibrium two-phase flows using the Baer-Nunziato model based on the Finite-Volume framework

An efficient bi-directional 1-D/3-D coupling is here proposed for the computation of compressible two-phase flows with the use of the Baer-Nunziato model. The objective is here to couple the 3-D Baer-Nunziato model with its 1-D counterpart involving spatially varying pipe cross-sections. The present coupling acts at the common interface between three-dimensional and one-dimensional computational domains. The proposed approach is built upon the framework of the Finite-Volume method with, in particular, the exchange of the numerical fluxes coming from the approximation of both conservative and non-conservative terms of the convective part of the Baer-Nunziato model. For this purpose, local Riemann problems at the 1-D/3-D common interface are considered for the computation of the corresponding numerical conservative and non-conservative fluxes. These local Riemann problems are based on the variables associated with the 1-D domain on one side and the variables coming from the 3-D domain on the other side of the interface. The potentially non-null tangential phasic velocity components coming from the 3-D domain at the coupling interface are also considered in the local Riemann problems. In addition, adequate approximations of the non-conservative terms associated with changes of volume fraction as well as changes of cross-section are considered at the 1-D/3-D interface. As a consequence, conservation properties such as the uniform pressure and velocity profiles preservation are ensured by the present 1-D/3-D coupling. The pipe cross-section variations are also taken into account in the present method. What is more, no iterative procedure is required in the proposed approach. Several numerical shock-tubes involving both subsonic and supersonic configurations of the Baer-Nunziato model and pipe cross-section variations are then considered to assess the present 1-D/3-D coupling. The influence of the angle between the 1-D and the 3-D domains at the coupling interface is also studied. Finally, the propagation of a shock-wave in a circular tube with a sudden change in cross-section is simulated using a hybrid 1-D/3-D computation showing the potential of the proposed geometrical multi-scale strategy.