Construction Of Interface Research Articles

Homogeneous triple-phase interfaces enabling one-pot route to metal compound/carbon composites

Metal compounds (e.g., metal phosphides/sulfides/selenides) coupled with carbon materials have recently drawn great attraction for boosting the electrochemical performances because of their appealing synergistic effect and valuable structural stability. Despite many examples for their synthesis exist, there is still a need for a simplistic and comprehensive approach to such metal compound/carbon (MC/C) composites. Herein, an effective, facile, yet versatile strategy to produce various types of MC/C composites is presented. Key to this strategy is construction of a homogeneous triple-phase interface, which is realized by utilization of a hybrid assembly integrated with carbon, metal and sulfide (or selenide, phosphide) precursors through coupling metal cations with anion groups of a functional polymer. Such an intimately binding carbon-metal-sulfide (or selenide, phosphide) interface structure enables the successful in situ generation of MC nanoparticles uniformly encapsulated into the carbon matrix just after a one-step carbonization treatment. The present synthetic strategy provides remarkable adjustability, predictability and generality to facilely fabricate a series of MC/C composites, offering sufficient freedom to explore their unique energy storage/conversation properties. As a proof of concept, the as-prepared SnS/C composite exhibits superior lithium ion and potassium ion storage capabilities when used as anode materials for alkali-metal ion batteries. The present work provides impressive insights into the design principles for MC/C composites that are the potential materials in targeted application fields, and opens up an efficacious avenue for their facile synthesis as well.

Ultra‐High Initial Coulombic Efficiency Induced by Interface Engineering Enables Rapid, Stable Sodium Storage

AbstractHigh initial coulombic efficiency is highly desired because it implies effective interface construction and few electrolyte consumption, indicating enhanced batteries’ life and power output. In this work, a high‐capacity sodium storage material with FeS2nanoclusters (≈1–2 nm) embedded in N, S‐doped carbon matrix (FeS2/N,S‐C) was synthesized, the surface of which displays defects‐repaired characteristic and detectable dot‐matrix distributed Fe‐N‐C/Fe‐S‐C bonds. After the initial discharging process, the uniform ultra‐thin NaF‐rich (≈6.0 nm) solid electrolyte interphase was obtained, thereby achieving verifiable ultra‐high initial coulombic efficiency (≈92 %). The defects‐repaired surface provides perfect platform, and the catalysis of dot‐matrix distributed Fe‐N‐C/Fe‐S‐C bonds to the rapid decomposing of NaSO3CF3and diethylene glycol dimethyl ether successfully accelerate the building of two‐dimensional ultra‐thin solid electrolyte interphase. DFT calculations further confirmed the catalysis mechanism. As a result, the constructed FeS2/N,S‐C provides high reversible capacity (749.6 mAh g−1at 0.1 A g−1) and outstanding cycle stability (92.7 %, 10 000 cycles, 10.0 A g−1). Especially, at −15 °C, it also obtains a reversible capacity of 211.7 mAh g−1at 10.0 A g−1. Assembled pouch‐type cell performs potential application. The insight in this work provides a bright way to interface design for performance improvement in batteries.

Ultra‐High Initial Coulombic Efficiency Induced by Interface Engineering Enables Rapid, Stable Sodium Storage

High initial coulombic efficiency is highly desired because it implies effective interface construction and few electrolyte consumption, indicating enhanced batteries' life and power output. In this work, a high-capacity sodium storage material with FeS2 nanoclusters (≈1-2 nm) embedded in N, S-doped carbon matrix (FeS2 /N,S-C) was synthesized, the surface of which displays defects-repaired characteristic and detectable dot-matrix distributed Fe-N-C/Fe-S-C bonds. After the initial discharging process, the uniform ultra-thin NaF-rich (≈6.0 nm) solid electrolyte interphase was obtained, thereby achieving verifiable ultra-high initial coulombic efficiency (≈92 %). The defects-repaired surface provides perfect platform, and the catalysis of dot-matrix distributed Fe-N-C/Fe-S-C bonds to the rapid decomposing of NaSO3 CF3 and diethylene glycol dimethyl ether successfully accelerate the building of two-dimensional ultra-thin solid electrolyte interphase. DFT calculations further confirmed the catalysis mechanism. As a result, the constructed FeS2 /N,S-C provides high reversible capacity (749.6 mAh g-1 at 0.1 A g-1 ) and outstanding cycle stability (92.7 %, 10 000 cycles, 10.0 A g-1 ). Especially, at -15 °C, it also obtains a reversible capacity of 211.7 mAh g-1 at 10.0 A g-1 . Assembled pouch-type cell performs potential application. The insight in this work provides a bright way to interface design for performance improvement in batteries.

Constructing a Multifunctional Interface between Membrane and Porous Transport Layer for Water Electrolyzers.

The cell performance and durability of polymer electrolyte membrane (PEM) water electrolyzers are limited by the surface passivation of titanium-based porous transport layers (PTLs). In order to ensure stable performance profiles over time, large amounts (≥1 mg·cm-2) of noble metals (Au, Pt, Ir) are most widely used to coat titanium-based PTLs. However, their high cost is still a major obstacle toward commercialization and widespread application. In this paper, we assess different loadings of iridium, ranging from 0.005 to 0.05 mg·cm-2 in titanium PTLs, that consequently affect the investment costs of PEM water electrolyzers. Concerning a reduction in the precious metal costs, we found that Ir as a protective layer with a loading of 0.025 mg·cm-2 on the PTLs would be sufficient to achieve the same cell performance as PTLs with a higher Ir loading. This Ir loading is a 40-fold reduction over the Au or Pt loading typically used for protective layers in current commercial PEM water electrolyzers. We show that the Ir protective layer here not only decreases the Ohmic resistance significantly, which is the largest part of the gain in performance, but moreover, the oxygen evolution reaction activity of the iridium layer makes it promising as a cost-effective catalyst layer. Our work also confirms that the proper construction of a multifunctional interface between a membrane and a PTL indeed plays a crucial role in guaranteeing the superior performance and efficiency of electrochemical devices.

Coupling Interface Constructions of FeNi3-MoO2 Heterostructures for Efficient Urea Oxidation and Hydrogen Evolution Reaction

Urea electrolysis has prospects for urea-containing wastewater purification and hydrogen (H2) production, but the shortage of cost-effective catalysts restricts its development. In this work, the tomentum-like FeNi3-MoO2 heterojunction nanosheets array self-supported on nickel foam (NF) as bifunctional catalyst is prepared by facile hydrothermal and annealing method. Only 1.29 V and -50.8 mV is required to obtain ±10 mA cm-2 for urea oxidation and hydrogen evolution reaction (UOR and HER), respectively, showing great bifunctional catalytic activity. For overall urea electrolysis, it only needs 1.37 V to reach 10 mA cm-2 and can last at 100 mA cm-2 for 70 h without obvious activity attenuation, showing outstanding durability. Coupling interface constructions of FeNi3-MoO2 heterostructures, novel morphology with a mesoporous and self-supporting structure could be the reason for this good performance. This work thus proposes a promising catalyst for boosting UOR and HER to realize efficient overall urea electrolysis.

NPLIC: A machine learning approach to piecewise linear interface construction

Volume of fluid (VOF) methods are extensively used to track fluid interfaces in numerical simulations, and many VOF algorithms require that the interface be reconstructed geometrically. For this purpose, the Piecewise Linear Interface Construction (PLIC) technique is most frequently used, which for reasons of geometric complexity can be slow and difficult to implement. Here, we propose an alternative neural network based method called NPLIC to perform PLIC calculations. The model is trained on a large synthetic dataset of PLIC solutions for square, cubic, triangular, and tetrahedral meshes. We show that this data-driven approach results in accurate calculations at a fraction of the usual computational cost, and a single neural network system can be used for interface reconstruction of different mesh types.

Research on Electromagnetic Wave Propagation and Optical Characteristics Based on Optical Transfer Matrix Method

The processing of electromagnetic waves by means of optical transmission matrix can be applied through multi-layer homogenization media, and finally real-time transmission can be realized. After that, it can derive the transmission matrix based on the interface and propagation matrix construction, and finally obtain the reflection and permeability coefficients. This article summarizes the content of the transmission matrix method based on previous work experience. The author discusses the propagation and optical characteristics of physical electromagnetic waves based on the optical transmission matrix method from four aspects: reflection-increasing film analysis, DBR design, reflectance calculation of fiber multi-directional laminates, plane wave propagation and reflection in the medium.

Construction of electrochemical chiral interface of C3N4/Ppy/ self-assembled polysaccharide

A simple and effective chiral selector is reported baseing on Cu2+ and β-cyclodextrin (Cu-β-CD), which can be self-assembled with sodium alginate (SA) as a chiral sensor (SA-CD). The composite of C3N4 and Ppy (C3N4/Ppy) was used as an electroactive material for the enantiomeric selection of tryptophan (Trp) by differential pulse voltammetry (DPV). The sensor was constructed by combining the advantages of polysaccharide SA-CD and C3N4/Ppy. SA-CD as a chiral selector can provide a large number of chiral sites, and C3N4/Ppy as a substrate material can improve the electrochemical signal. The results showed that the electrochemical signal of C3N4/Ppy/SA-CD modified GCE to l-Trp was higher than that to d-Trp. This was due to the low affinity of C3N4/Ppy/SA-CD modified GCE to l-Trp, which made it easier for l-Trp to penetrate the electrode modified film and reach the electrode surface, resulting in a greater peak current. UV–vis and water contact angle further proved that C3N4/Ppy/SA-CD had higher binding ability to d-Trp. In addition, the sensor had good reproducibility and stability, and can be regarded as a promising platform for chiral sensing.

Construction of a Cu-Sn Heterojunction Interface Derived from a Schottky Junction in Cu@Sn/rGO Composites as a Highly Efficient Dielectric Microwave Absorber.

Developing high-performance dielectric absorbers, low filler loading, and a broad absorption band remains a great challenge for wireless data communication systems, household appliances, local area network, and so on. Herein, we report a facile green method to design and fabricate a copper-coated tin/reduced graphene oxide (Cu@Sn/rGO) composites with a heterojunction obtained by modifying a Schottky junction. The unique heterojunction can enable an appropriate balance between impedance and strong loss capacity. Meanwhile, it can not only promote the carrier migration but also obtain the rich interfaces. Consequently, a Cu@Sn/rGO composite with a heterojunction exhibits superior absorption intensity, far surpassing that of other absorbing materials reported. With a weight content of only 5 wt %, the maximum absorptivity reaches -49.19 dB at 6.08 GHz, and an effective absorption bandwidth (RL < -10 dB) of 13.94 GHz is achieved when the absorber's thickness ranges from 1.7 to 5.5 mm. This study provides new insights into the design and synthesis of a novel microwave absorption material with lightweight, smaller filler loading, and strong reflection loss.

Effects of Implicit and Explicit Focus on Form on L2 Acquisition of the English Passive: An Analysis of Intra-Learner Variation

This study investigated intra-learner variation in the effects of implicit and explicit focus on form (FonF) on second language (L2) acquisition of the English passive, an interface construction. The study employed a pretest-posttest-delayed posttest design, with five treatment sessions between the pretest and posttests. Implicit FonF was operationalized as textual enhancement (TE), and explicit FonF as consciousness-raising (C-R). Five different outcome measures were utilized to examine the respective treatment effects on the form, meaning, and function of the passive. Data were collected with four Korean high school students, two engaging in TE and the other two in C-R, whose developmental routes through the experiment were analyzed quantitatively and qualitatively. The results of the analysis showed that implicit and explicit FonF led to differential variation within each learner, not only across the outcome measures but also over time, yet were suggestive of a potential benefits to each for the different domains encompassed in the passive. These results are further discussed in relation to the learners’ proficiency levels and the types of errors they produced.

Construction of compatible interface of straw/magnesium oxychloride lightweight composites by coupling agents

To solve the problem of agricultural waste, modified straw/magnesium oxychloride lightweight composites (M−SMOCL) with light-weight and high strength were prepared using magnesium oxychloride cementitious material (MOC) as the matrix, modified straw as reinforcing material and other reagents as additives. The effects of coupling agents, including KH-550, KH-560, KBM-603, HY-201, on straw groups and water absorption, as well as the mechanical strength and water resistance of the composites, were examined and discussed. The results showed that coupling agents reduced straw hydrophilicity and water absorption, improved composite performance. KBM-603 in particular possessed the best modification effects, with water absorption of straw treated with KBM-603 decreased to 27%, and the composite compressive and bending strengths of reached the maximum values of 12.93 MPa and 4.78 MPa, respectively. FT-IR and SEM showed that straw treated with KBM-603 bonded more closely to the matrix, creating the best interface results.

Numerical study for the improvement of bead spreading architecture with modified nozzle geometries in additive manufacturing of polymers

Purpose This paper aims to develop a numerical model of bead spreading architecture of a viscous polymer in fused filament fabrication (FFF) process with different nozzle geometry. This paper also focuses on the manufacturing feasibility of the nozzles and 3D printing of the molten beads using the developed nozzles. Design/methodology/approach The flow of a highly viscous polymer from a nozzle, the melt expansion in free space and the deposition of the melt on a moving platform are captured using the FLUENT volume of fluid (VOF) method based computational fluid dynamics code. The free surface motion of the material is captured in VOF, which is governed by the hydrodynamics of the two-phase flow. The phases involved in the numerical model are liquid polymer and air. A laminar, non-Newtonian and non-isothermal flow is assumed. Under such assumptions, the spreading characteristic of the polymer is simulated with different nozzle-exit geometries. The governing equations are solved on a regular stationary grid following a transient algorithm, where the boundary between the polymer and the air is tracked by piecewise linear interface construction (PLIC) to reconstruct the free surface. The prototype nozzles were also manufactured, and the deposition of the molten beads on a flatbed was performed using a commercial 3D printer. The deposited bead cross-sections were examined through optical microscopic examination, and the cross-sectional profiles were compared with those obtained in the numerical simulations. Findings The numerical model successfully predicted the spreading characteristics and the cross-sectional shape of the extruded bead. The cross-sectional shape of the bead varied from elliptical (with circular nozzle) to trapezoidal (with square and star nozzles) where the top and bottom surfaces are significantly flattened (which is desirable to reduce the void spaces in the cross-section). The numerical model yielded a good approximation of the bead cross-section, capturing most of the geometric features of the bead with a reasonable qualitative agreement compared to the experiment. The quantitative comparison of the cross-sectional profiles against experimental observation also indicated a favorable agreement. The significant improvement observed in the bead cross-section with the square and star nozzles is the flattening of the surfaces. Originality/value The developed numerical algorithm attempts to address the fundamental challenge of voids and bonding in the FFF process. It presents a new approach to increase the inter-bead bonding and reduce the inter-bead voids in 3D printing of polymers by modifying the bead cross-sectional shape through the modification of nozzle exit-geometry. The change in bead cross-sectional shape from elliptical (circular) to trapezoidal (square and star) cross-section is supposed to increase the contact surface area and inter-bead bonding while in contact with adjacent beads.

Flow around Ship Spoiler.(Dept.M)

To control the roll, pitch motion and speed of the ship, a proposed system of spoilers is mounted at the bottom of the ship. The bow spoilers consist of an even number of sections arranged port and starboard forward of the center of mass of me ship. The stem spoilers consist of an even number of sections arranged port and starboard attached to the ship's transom or transom plate. Injecting exhaust gas stabilizes cavities behind spoilers. The forces and moments acting on the ship's bottom depend on its inclination, spoiler extensions and positions of the spoilers relative to the ship's center of mass. To improve the understanding of the parameters affecting the flow field around such spoiler, we computed the flow field with different spoiler position, and inclination angle with air flow injection. We used a three-dimensional Navier-Stokes code (CFDRC, 2000) to model the two-phase (low field around a ship spoiler with the Free Surface simulation In Piecewise Linear Interface Construction (PUC) method. The governing equations are discretized on a structured grid using an upwind difference scheme. For different conditions, we detemline the bubbles shape, the two-dimensional flowfield around the spoiler body and the pressure variation on the wake of the spoiler body. Higher spoiler inclination angle gives higher pressure difference between front and back of the spoiler. Spoiler with injection at a distance L from ship spoiler gives higher pressure difference between front and back of the spoiler than injection just beside the spoiler In spoiler with 45o inclination angle the cavity has high stability with long bubble foot shape. The bubble shape depends on the spoiler position and inclination. These parameters affect the roll, pitch and speed of the ship.

Research progress of fluorine-containing electrolyte additives for lithium ion batteries

The construction of Solid Electrolyte Interface (SEI) film in Li-ion batteries with functional electrolyte additives is able to passivate the active material surface and inhibit the decomposition of the electrolyte continuously. In addition, safety issue is also an important factor restricting the large scale application of present lithium-ion batteries. Therefore, the additives for film-forming and safety enhancement are a class of cost-effective components that promote the application and development of batteries. Fluorine is a kind of “bipolar” element, which has strong electronegativity and weak polarity. Fluorine-containing electrolyte additives have excellent kinetic reactivity, which can preferentially generate stable SEI films and uniform Cathode-Electrolyte Interface (CEI) films to effectively improve the electrochemical performance of the batteries. Meanwhile, fluorine-containing electrolyte additives can also be used as flame-retardants to improve safety performance. In this review, we summarize the research status of fluorine-containing additives in recent years and elaborate its reaction mechanisms of improving battery performance. Finally, a personal perspective on the future of the development of fluorine-containing additives is presented.

Numerical and Experimental Analysis of Transient 2D Flow around Ship Spoiler.(Dept.M)

An experimental analysis and numerical computation were conducted for flow around ship spoiler mounted at the bottom of the ship and subjected to air injection The air was injected beside the spoiler and at a distance equals the spoiler length to stabilize cavities behind spoilers. This system was proposed to control the roll, pitch motion and speed of the ship, with injecting exhaust gas behind spoilers. The forces and moments acting on the ship's bottom depend on spoilers' inclination, extensions and positions relative to the ship's center of mass. To improve the understanding of the parameters affecting the flow field aroundsuch spoiler, experimental images of bubble formation are triggered and compared with the computed flow field at different spoiler inclination angle, and air injection position. Two dimensional Navier-Stokes code is used to model the two-phase flow field around a ship spoiler with the free surface simulation in Piecewise Linear Interface Construction (PLIC) method. The governing equations are discretized on a structured grid using an upwind difference scheme. For different conditions, the bubbles shape, the two-dimensional flow field around the spoiler body and the pressure variation on the wake of the spoiler body are computed, Flow field and bubble formation around the spoiler are recorded experimentally at different condition and time sequence with scientific video camera The Froude number was about 1.6 based on spoiler length. The computational and experimental results show that there is a good matching of bubble formation in the spoiler with 90', but in the condition of 45° the experimental images show that bubble filled the space between the bubble and the body of the ship. This is may be due to the two-dimension computational model consideration. So, a water layer was isolated between the bubble and the ship body. In the case of spoiler with 45° inclination angle, the flow is circulated inside the bubble. The bubble shape is longer which gives more negative pressure on larger area. The moment around the 450 spoiler fixationpoint is seven times of that around the 90° spoiler. In double injection condition beside and at a distance equal the horizontal spoiler length downstream the spoiler, the bubbles are more stable and the moment is higher by 7.9 and 17.8 times after 1.2 and 2 seconds, respectively, than that around the 90° spoiler. Thus, changing inclination spoiler angle and position relative to injection angle will give different bubble shapes which give different forces to control the roll, pitch motion and speed of the ship.

Monolithic Solvers for Incompressible Two-Phase Flows at Large Density and Viscosity Ratios

In this paper, we investigate the accuracy and robustness of three classes of methods for solving two-phase incompressible flows on a staggered grid. Here, the unsteady two-phase flow equations are simulated by finite volumes and penalty methods using implicit and monolithic approaches (such as the augmented Lagrangian and the fully coupled methods), where all velocity components and pressure variables are solved simultaneously (as opposed to segregated methods). The interface tracking is performed with a Volume-of-Fluid (VOF) method, using the Piecewise Linear Interface Construction (PLIC) technique. The home code Fugu is used for implementing the various methods. Our target application is the simulation of two-phase flows at high density and viscosity ratios, which are known to be challenging to simulate. The resulting strategies of monolithic approaches will be proven to be considerably better suited for these two-phase cases, they also allow to use larger time step than segregated methods.

Method of construction of adaptive interface of multimedia product

Method of construction of adaptive interface of multimedia product

Development of a universal conductive platform for anchoring photo- and electroactive proteins using organometallic terpyridine molecular wires.

The construction of an efficient conductive interface between electrodes and electroactive proteins is a major challenge in the biosensor and bioelectrochemistry fields to achieve the desired nanodevice performance. Concomitantly, metallo-organic terpyridine wires have been extensively studied for their great ability to mediate electron transfer over a long-range distance. In this study, we report a novel stepwise bottom-up approach for assembling bioelectrodes based on a genetically modified model electroactive protein, cytochrome c553 (cyt c553) and an organometallic terpyridine (TPY) molecular wire self-assembled monolayer (SAM). Efficient anchoring of the TPY derivative (TPY-PO(OH)2) onto the ITO surface was achieved by optimising solvent composition. Uniform surface coverage with the electroactive protein was achieved by binding the cyt c553 molecules via the C-terminal His6-tag to the modified TPY macromolecules containing Earth abundant metallic redox centres. Photoelectrochemical characterisation demonstrates the crucial importance of the metal redox centre for the determination of the desired electron transfer properties between cyt and the ITO electrode. Even without the cyt protein, the ITO-TPY nanosystem reported here generates photocurrents whose densities are 2-fold higher that those reported earlier for ITO electrodes functionalised with the photoactive proteins such as photosystem I in the presence of an external mediator, and 30-fold higher than that of the pristine ITO. The universal chemical platform for anchoring and nanostructuring of (photo)electroactive proteins reported in this study provides a major advancement for the construction of efficient (bio)molecular systems requiring a high degree of precise supramolecular organisation as well as efficient charge transfer between (photo)redox-active molecular components and various types of electrode materials.

Multi-Layer Active Interface Construction with Polyphenols and Nano-Silver on Nano Collagen Fiber for Efficient Capturing Iodine Vapor

Multi-Layer Active Interface Construction with Polyphenols and Nano-Silver on Nano Collagen Fiber for Efficient Capturing Iodine Vapor

A ghost-cell immersed boundary method for unified simulations of flow over finite- and zero-thickness moving bodies at large CFL numbers

A ghost-cell immersed boundary method for unified simulations of flow over finite- and zero-thickness moving bodies at large Courant-Friedrichs-Lewy (CFL) numbers is presented. In order to handle such bodies in a unified manner, algorithms for interface construction and cell demarcation are proposed. The main challenge in treating zero-thickness bodies is to maintain sharpness and accuracy even at large CFL numbers with diminished spurious force oscillations. Thus, the effect of large CFL numbers on the solution accuracy of fluid-structure interaction (FSI) problems involving zero-thickness bodies is investigated and necessary treatments to preserve solution accuracy even at large CFL numbers are suggested. The present study suggests two treatments which are important in preserving the accuracy and stability of the solution: backward time integration for computational cells called ‘swept-cells’ and pressure boundary condition with mass conservation. Composite implicit time integration for the dynamic equation of a thin elastic structure is employed for a stable simulation of FSI at large CFL numbers. By using large time step sizes, the present method not only enhances computational efficiency, but also suppresses spurious force oscillations while maintaining the sharpness of an infinitesimally thin body. The efficacy and accuracy of the present method are examined through numerical examples.