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Investigation of different potential instability phenomena is an essential part of a study of the structural behaviour of double-layer braced barrel vaults. In this context, the effects of the use of a reinforced concrete (RC) topping in composite action with double-layer grid-works on the instability behaviour of such structures were studied. Two types of double-layer flat grids and barrel vaults were considered: without any integral RC topping (non-composite grid-works) and with a RC topping in composite action with the spatial grid (composite grid-works). The primary models were selected and designed adopting a consistent procedure utilising the weight–density method. Initially, elastic buckling analyses were performed. Complementary studies included a series of non-linear finite-element analyses accounting for geometric and material non-linearities emphasising structural stability and the post-buckling behaviour. It was found that the presence of a rather thin layer of RC covering, in composite action with double-layer grids, increased both the initial buckling and the ultimate strengths of such structures substantially, and also significantly improved their post-buckling behaviour, resulting in much improved reliability against progressive failure and sudden loss of strength.

A thin and broadband frequency selective surface (FSS)-based magnetic absorber is presented for low-microwave frequency applications. The design consists of a double-layers of FSS with the combination of two different magnetic substrates, which provides a much broader bandwidth compared to existing single-layered designs. The magnetic materials are in-house made by mixing different ratios of carbonyl-iron powder with silicone elastomer polydimethylsiloxane (PDMS). The simple single-square loop (SSL) structure is used for both FSSs which are printed on a standard FR4 material using lossy resistive sheet. This configuration allows the use of a closed-form equivalent-circuit model for a fast and efficient bandwidth optimization. A genetic algorithm (GA) is utilized to obtain the design parameters for broadband absorption with minimum overall thickness. The measured results confirm that the proposed absorber operates from 0.78 to 4.8 GHz with -10 dB reflectivity. The design achieves 144% fractional-bandwidth with a 10.12 bandwidth-to-thickness ratio.

In this paper, several computer simulations have been carried out using lumerical FTDT software. As a result, the optimal layer thicknesses for antireflection coatings SiC/MgF2 and SiC/ZnO/MgF2 deposited on the surface of polished silicon were determined. Among the considered coatings, the double layer structure SiC (60 nm) + MgF2 (110 nm) has the lowest reflection (

The double-layer a-IGZO thin film transistors (DL-TFTs) using a quantum well channel and a top barrier can reduce the subthreshold swing and hysteresis by 0.73 $\times$ and 0.13 $\times$ , respectively, in the transfer characteristics using the bottom gate sweep as compared to the single-layer TFTs (SL-TFTs). The wide bandgap barrier on top of the narrow bandgap IGZO channel serves as a protection layer between the IGZO channel and the SiO2 top gate insulator to prevent plasma-induced damage on the IGZO channel caused by the S/D metal etching and the top gate insulator deposition. As for the mobility using the bottom gate operation with the top gate grounded, the DL-TFTs show higher mobility (1.06 $\times$ ) at the room temperature due to less Coulomb scattering caused by the plasma-induced damage for percolation conduction, while the SL-TFTs have higher mobility at low temperatures due to the improved hopping efficiency for thermally activated hopping. The hysteresis is temperature independent down to 160 K, indicating the electrons tunneling between the channel and the top gate insulator is dominant. As for the reliability, DL-TFT has a smaller Vth shift than SL-TFT under both positive bias temperature stress (PBTS) due to less subgap defect in the channel.

Surface complexation models (SCM), based mainly on the diffuse double layer (DDL) theory, have been used to predict zeta potential at the crude oil-brine-rock (COBR) interface with limited success. However, DDL is inherently limited in accurately predicting zeta potential by the assumptions that all the brine ions interact with the rock surface at the same plane and by the double layer collapse at higher brine ionic strength (>1M). In this work, a TLM-based SCM captured zeta potential trends at the calcite-brine interface with ionic strength up to 3 M. An extended DDL and TLM-based SCMs were used to predict the electrokinetic properties of a composite carbonate rock showing a different mineralogical composition. The extended TLM-based SCM captured the zeta potential prediction trends and magnitude, highlighting the contribution of the inorganic minerals and organic impurities on the composite carbonate surface. In contrast, the extended DDL-based SCM captured the zeta potential trends but failed to capture the magnitude of the measured zeta potential. Interestingly, the TLM-based SCM predicted a positive SP for the rock-brine interface, which could explain the oil-wet nature of composite carbonate rocks due to electrostatic adsorption of negatively charged carboxylic acids. Conversely, the DDL-based SCM predicted a negative SP, leading to an inaccurate interpretation of the electrokinetic properties at the rock-brine interface. Thus, the use of extended TLM-based SCM was required to accurately predict the zeta potential and account for the adsorption of carboxylic acids on the reservoir composite carbonate surface.

Functionalisation of technological nanopores and investigation of their transport properties have attracted considerable interest from scientific as from technological point of view, among others due to their potential regarding molecular transport design. Asymmetric design of nanopore structure and functionalisation is expected to trigger increased and directed transport of ionic species. Based on this motivation, we demonstrate a layer-selective polymer functionalisation in a mesoporous double layer thin film to generate nanoscale step gradient architectures with asymmetric charge distribution by taking advantage of co-condensation and polymer modification techniques. Thereby, mesoporous silica and co-condensed mesoporous amino silica thin films are combined to double layered films with a film thickness of 300 – 400 nm in both sequential arrangements, respectively. Iniferter initiated polymerisation is used to selectively functionalise only the amino silica layer with polymers such as poly(2-(methacryloyloxy)ethyltrimethylammonium chloride) (PMETAC) in a grafting from approach. Investigation of the ionic pore accessibility of the mesoporous double layered films before and after layer-selective polymer functionalisation shows that the ionic pore accessibility is dominated by the bottom layer when overcoming the electrostatic repulsion of the top layer.

The work presented in this paper concerns a method for the miniaturized frequency selective surface (FSS) based on the meander lines. A miniaturized dual-bandstop FSS structure based on meander lines with spiral-shape is proposed and simulated. The equivalent circuit and current distributions are introduced to explain the FSS performance. The size of the unit cell is 10 mm, which is about 0.037 wavelength at the first resonant frequency. Simulation results indicate that the proposed FSS has a frequency shift smaller than 1% for different polarizations with an oblique incident angle of 60°. A prototype of the FSS is fabricated and measured. The measurement results show that the FSS is polarization-insensitive and angle-insensitive.

Circular dichroism (CD) is widely used in enantiomer identification, photodetection, and circular polarization devices. Improving the CD signal of easily prepared 3D chiral nanostructures by design...

To reveal the engineering relationship among the electrical properties of embroidered conductive lines, the electrical properties and arrangements of conductive yarns, it is necessary to establish their equivalent resistance model. Embroidered conductive lines in textiles are usually fabricated by single-layer (conductive and nonconductive yarn used as upper and lower yarn) or double-layer embroidery technology (conductive yarns used as upper and lower yarn). Several researchers have proposed the simple resistance model for single-layer embroidered conductive line based on geometric structure of single conductive yarn in fabric. However, the double-layer conductive line has the contact resistance periodically interlaced by the upper and lower conductive yarns, and it made its equivalent circuit different from that of single-layer conductive line. In this work, a geometric model was built to describe the trace of conductive yarn in fabric, and in combination with Wheatstone Bridge theory, was applied to establish the equivalent resistance models of double-layer conductive lines with a certain width, consisted of various courses. First, the equivalent resistance model of double-layer conductive lines consisting of single course was proposed to calculate the contact resistance. Then, to obtain the electrical resistance of double-layer conductive lines with a certain width, the equivalent resistance model was extended from single course to multiple courses ([Formula: see text]). Finally, to validate the proposed equivalent resistance model, double-layer conductive lines with different embroidery parameters (stitch length and stitch spacing) on nonwoven fabric were fabricated and evaluated. The experimental results revealed that the proposed model accurately predicted the resistances of double-layer conductive lines.

Low-efficiency charge transfer is a critical factor to limit the photocatalytic H2 evolution activity of semiconductor photocatalysts. The interface design is a promising approach to achieve high charge-transfer efficiency for photocatalysts. Herein, a new 2D/2D atomic double-layer WS2/Nb2O5 shell/core photocatalyst (DLWS/Nb2O5) is designed. The atom-resolved HAADF-STEM results unravel the presence of an unusual 2D/2D shell/core interface in DLWS/Nb2O5. Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra, the average lifetime of charge carriers for DLWS/Nb2O5 (180.97 ps) is considerably shortened as compared to that of Nb2O5 (230.50 ps), strongly indicating that the 2D/2D shell/core interface enables DLWS/Nb2O5 to achieve ultrafast charge transfer from Nb2O5 to atomic double-layer WS2, thus yielding a high photocatalytic H2 evolution rate of 237.6 μmol/h, up to 10.8 times higher than that of pure Nb2O5 nanosheet. This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.

Background: The main objective was to compare the outcome of single layer interrupted extra-mucosal sutures with that of double layer suturing in the closure of colostomies. Subjects and Methods: Sixty-seven patients with closure colostomy were assigned in a prospective randomized fashion into either single layer extra-mucosal anastomosis (Group A) or double layer anastomosis (Group B). Primary outcome measures included mean time taken for anastomosis, immediate postoperative complications, and mean duration of hospital stay. Secondary outcome measures assessed the postoperative return of bowel function, and the overall mean cost. Chi-square test and student t-test did the statistical analysis.. Results: Thirty-two patients were allocated to group A and 35 patients to group B. The mean time taken for anastomosis was significantly shorter in group A (23.25 ± 1.20 min in group A vs. 36.71 ± 1.93 min in group B; P

We consider a double-layer structure consisting of a bilayer graphene sheet and a two-dimensional electron gas, isolated in a very thin GaAs quantum well. The collective excitations are determined from the zeroes of the dynamical dielectric function within the random-phase approximation, taking into account the temperature effects. Numerical calculations present that two plasmon modes exist in the system, similar to those in other double-layer structures. While the optical mode continues in the interband single-particle excitation area, the acoustic mode only crosses the intraband single-particle excitation boundary and disappears. Also, our investigations show that plasmon properties in the system are affected significantly by most of the chosen factors. Plasmon frequency increases as the separation increases while the increase in carrier density decreases noticeably these frequencies. Temperature affects plasmon characters similarly to but more weakly than that does in monolayer grapheme—two-dimensional electron gas double-layer structures. Finally, the temperature can increase the effects of some other parameters on plasmon properties of the system, so this factor should be taken into account in calculations to improve the model for better results.

The ice-breaking process of the double-layer charge at a depth of 150 cm underwater is simulated by LS-DYNA. This paper analyzes the load type, shock wave pressure characteristics and propagation behavior of the double-layer charge during underwater explosion. By analyzing the impact of the shock wave pressure in the water under different charge intervals and time intervals on the shock wave pressure of the double charge, it is concluded that the peak pressure of the double charge explosion shock wave is jointly determined by the double charge. In this range, the second peak pressure value of the drug is greater than the pressure value of the first peak of the drug, and the attenuation is slow; the delay time of the upper charge has little effect on the peak pressure value of the shock wave in the water; the delay time is higher than that of the lower charge Initiation, at the same position, the total pressure peak of the shock wave formed by the delay of the upper charge is larger.

The purpose of the research is to assess the sound absorption performance (SAP) of acoustic metamaterials made of double-layer Nomex honeycomb structures in which a micro-orifice corresponds to a honeycomb unit. For this purpose, the influences of structural parameters on the SAP of acoustic metamaterials were investigated by using experimental testing and a validated theoretical model. In addition, the sandwich structure was optimized by the genetic algorithm. The research shows that the panel thickness and micro-orifice diameter mainly affect the second resonant frequency and second peak sound absorption coefficient (SAC) of the structure. The unit cell size is found to influence the first and second resonant frequencies and two peaks of the SAC. An extremely low side-length of the honeycomb core decreases the SAP of the structure for low-frequency noise signals. Additionally, the sandwich structure presents a better SAP when the diameter of micro-orifices on the front micro-perforated panel (MPP) exceeds that of the back MPP. The sandwich structure shows better noise reduction performance after the optimization aiming at the noise frequency outside trains.

A genetic algorithm was employed as a novel method to determine the best combination of materials for a double-layer electromagnetic shielding composite with good electromagnetic wave absorption efficiency at high frequencies from numerous magnetic materials. A carbonyl iron soft magnetic composite and a flaky FeNi soft magnetic composite were used to form the double-layer composite. The reflection and transmission parameters of the double-layer composite were measured using a vector network analyzer. The electromagnetic shielding effectiveness (SE) of the double-layer composite was calculated and analyzed. The double-layer composite was composed of two shielding materials with different electromagnetic parameters and demonstrated an excellent electromagnetic SE greater than 20 dB above 4 GHz; the ratio of the absorption efficiency (SEA) to SE (SEA/SE) was greater than 0.95, which indicates that more than 95% of the electromagnetic waves at high frequencies were attenuated by the shielding material, rather than being scattered into the surrounding environment. The double-layer composite exhibits excellent performance toward high electromagnetic waves absorption during the EMI shielding process.

The micro-perforated panel (MPP) has only one sound absorption peak, and the sound absorption performance is poor in the wide frequency range. Besides, the stiffness and strength of MPP are insufficient, so it can not bear the external load. In this study, double layers of hierarchical square honeycomb are placed within the air-back cavity of MPP to produce a sandwich structure. On the one hand, hierarchical honeycombs divide the air-back cavity into several sub-cavities. The perforations on the panel together with the sub-cavities form a series-parallel system of Helmholtz resonators. The sound absorption curve of the structure has multiple peaks and the half-absorption bandwidth is extensively widened. On the other hand, the hierarchical honeycomb with excellent load-bearing properties can strongly support the MPP to resist external loads. This new structure possesses both sound absorption and load bearing capabilities, and has practical application value in the noise reduction of high-speed trains and civil aircraft. Through theoretical and simulation analysis, the sound absorption performance of the structure is systematically studied and the influence of key parameters is quantified, providing guidance for the design of noise reduction materials.

Comparative studies are performed on the fundamental characteristics of charging classical dielectrics (PMMA) and ferroelectrics (LiNbO3) upon ion irradiation. Samples in experiments are irradiated with Ar+ ions having energies of 5–10 keV. General patterns are revealed in the kinetics of charging and typical differences in the characteristics of the current of the emitted ions, the displacement current (charge accumulation), and the surface potential. The first characteristic feature of charging ferroelectrics is the emergence of additional current in the detecting devices (the current of repolarization). The second feature is the presence of a double layer of charges on the surfaces of ferroelectrics. This double layer affects all kinetic characteristics of charging.

In the present study a double layer mucoadhesive buccal film containing nanocarriers encapsulated with neem extract was fabricated through electrospinning and solvent casting techniques for dental therapeutic applications. The morphological, physical and mucoadhesive properties of the resulting electrospun and solvent cast oral films were mutually compared, and their drug release behavior and antibacterial activity were further investigated. Chitosan/poly(vinylalcohol) (PVA) as a mucoadhesive component and phenylalanine amino acid nanotubes (PhNTs)-containing neem extract as a drug nanocarrier were used to fabricate oral films. A poly(caprolactone) (PCL) layer was used as an impermeable backing layer to protect the mucoadhesive component from tongue movement and drug loss. The results indicated an interconnected porous and fully filled solid structures for electrospun and solvent cast films, respectively. The physicomechanical parameters of the samples such as pH, weight, thickness, folding endurance and tensile strength were also evaluated. The crosslinked electrospun buccal film indicated better swelling and mucoadhesive properties compared to the solvent cast film. In addition, the drug loading capacity and encapsulation efficiency of the solvent cast film showed lower experimental values than those of electrospun oral film. On the other hand, the electrospun oral film had a well-controlled release of neem extract up to 82% at oral pH, which is best fitted to the Weibull model, and demonstrated the highest antibacterial properties against S. mutans bacteria with high biocompatibility on L929 fibroblast cells. Generally, the synthesized electrospun mucoadhesive film has a better potential for oral therapeutic applications than the solvent cast film.

The effect of double-layer nanoparticles (DNPs) on vascular restenosis was investigated in this study, which were prepared by combining vascular endothelial growth factor (VEGF) and paclitaxel (PTX). Different blank NPs (Blank), VEGF NPs, PTX-NPs single-layer NPs (PTX-NPs), and DNPs were prepared with VEGF, PTX, polylactic-polyglycolic acid (PLGA), and polyvinyl alcohol (PVA), so as to analyze the cytotoxicity of NPs. Besides, different NPs were compared in terms of the characterization, encapsulation efficiency (EE), in vitro release (IVR), and cell proliferation inhibition ability. 30 adult New Zealand white rabbits were selected to construct a balloon injury model (BIM). Then, they were divided into 5 groups according to different treatment NPs, including a model group (BIM), a Blank group (BIM + Blank NPs); a PTX-NP group (BIM + PTX-NPs), a VEGF-NPs group (BIM + VEGF-NPs), and DNPs group (BIM + DNPs), with 6 rabbits in each group. There was a comparison on the histology, arterial stenosis, hyperplasia index (HI), and intimal thickness (IT) of arterial vessels from different groups, and immunohistochemistry was employed to analyze the changes of VEGF and C-reactive protein (CRP) protein expression levels in arterial tissues of different groups. The results showed that the cell survival rate (SR) was 88.69 ±3.17% and 90.64 ± 1.86% in turn when PLGA and PVA were both 100 ¿tg/mL. The polydispersity index (PDI), minimal Zeta potential (ZP), and average particle size (APS) of DNPs were 0.16 ±0.02, -8.45 ±0.07, and 242.26 ±2.58 nm, respectively. The drug loading (DL) of PTX and plasmid VEGF 165 in DNPs were 29.33% and 4.93%, respectively. The release of PTX from DNPs on the 30th day was close to 50%, and the cumulative release of deoxyribonucleic acid (DNA) was close to 75%. There was no obvious difference in the cell SR within 7 days after DNPs were added into Chinese Hamster ovary (CHO) cells and vascular smooth muscle cells (VSMC) compared with the control group (P > 0.05). The arterial stenosis, HI, and IT of the DNPs group were greatly lower than those of the model group (P < 0.05). The expression of VEGF protein in arterial tissues of DNPs group was higher in contrast to the model group (P < 0.01), while the expression of CRP protein was lower than that of the model group (P < 0.05). It showed that the DNPs combined with VEGF and paclitaxel administered by balloon infusion could obviously inhibit the vascular restenosis by increasing the expression of VEGF and reducing the expression of CRP, which provided a reference for the clinical prevention and treatment of postoperative vascular restenosis.

External control of chemical processes is a subject of widespread interest in chemical research, including control of electrocatalytic processes with significant promise in energy research. The electrochemical double-layer is the nanoscale region next to the electrode/electrolyte interface where chemical reactions typically occur. Understanding the effects of electric fields within the electrochemical double layer requires a combination of synthesis, electrochemistry, spectroscopy, and theory. In particular, vibrational sum frequency generation (VSFG) spectroscopy is a powerful technique to probe the response of molecular catalysts at the electrode interface under bias. Fundamental understanding can be obtained via synthetic tuning of the adsorbed molecular catalysts on the electrode surface and by combining experimental VSFG data with theoretical modelling of the Stark shift response. The resulting insights at the molecular level are particularly valuable for the development of new methodologies to control and characterize catalysts confined to electrode surfaces. This Perspective article is focused on how systematic modifications of molecules anchored to surfaces report information concerning the geometric, energetic, and electronic parameters of catalysts under bias attached to electrode surfaces., Heterogeneous electrocatalysis: characterization of interfacial electric field within the electrochemical double layer.

Fiber dispersion was one of the crucial factors, which influenced the mechanical properties of fiber reinforced metal matrix composites (FR-MMCs). The incomprehension of fiber dispersion mechanisms and the lack of control methods limited the developments and further applications of the 3D printed FR-MMCs. In this work, the tensile properties and microstructures of continuous carbon fiber reinforced SnPb matrix composites, which were fabricated by the double-layer printing head 3D printing process (DPP), were measured and observed. The dual mechanisms of capillarity pressure driving and nonuniform interface reaction driving in fiber dispersion were proposed. Besides, the dynamic of fiber dispersion was discussed. It was found that improving wicking performance could increase the dispersion of fibers. This research filled in the blank of fiber dispersion mechanisms of 3D printed FR-MMCs, and provided the methodological supports for further improving the performances of composites.

In this paper, we propose a new intelligent temperature-controlled ventilated double-layer Trombe wall system for cold climate zones. This system consists of an insulation layer, an inner air chann...

Thin-walled tubes are widely used as energy absorption devices because of their excellent crashworthiness. In this paper, a novel tubular configuration with a double-layer sinusoidal corrugated sec...

Heat gain through glazing is a major source of the space cooling load in subtropical cooling-dominant climates. Application of energy-efficient glazing systems can significantly reduce the energy consumption of air conditioning in summer. Thus, it has become a popular research topic. In this study, a sample of silica aerogel glazing was developed and prepared. Two identical insulated boxes were then constructed; one faÇade was equipped with the aerogel glazing sample and the other was prepared with a conventional double-layer glazing. An onsite measurement of the boxes’ internal thermal properties was then conducted. The two boxes were placed within the same outdoor environment. The temperature, humidity, and enthalpy values were calculated with the boxes facing different orientations and in a variety of weather conditions. The performance of the silica aerogel glazing was then evaluated by both experimental and theoretical analysis. The results of this study will provide a basis for aerogel glass building application guidelines.

The ion distribution and its dynamic at the interface between solid and liquid play the main role in many applications. Measuring the solution at the solid–liquid interface in situ and noninvasively has been challenging because the electrolyte solution is volatile. Traditional ion beam analysis suffers from the energy straggling caused by the thick window and high-resolution analysis requires in-vacuum measurement. In this work, a cell with a 25 nm thick entrance window was fabricated. Solution of 0.1 mol/l BaCl2 was measured with 2 MeV He+ at the solid-electrolyte interface. It was revealed that a double layer structure was observed from the RBS spectrum. After measuring the cell for 4 h, there was no visible damage to the window. Therefore, this method can be used to measure the electrolyte solution in a vacuum in situ. It can also be expanded to measure gas or other volatile samples.

This study reports that photodetectors based on double‐layer ZnO nanorods grown on AZO seed layer by hydrothermal method. Compared with the photodetectors with single‐layer nanorods, the on/off ratio of the photodetectors with double‐layer ZnO nanorods is increased by ∼2.52 times, the photoresponsivity is increased ∼5.50 times, the sensitivity is increased ∼3.34 times and the response time was shortened by 0.97 and 6.65 s, respectively. Furthermore, the photocurrent derivative also shows that the photodetectors based on double‐layer ZnO nanorods has a faster response speed.

This case report illustrates the successful use of the double-layer amniotic membrane technique in a child with glaucoma and aniridia. A 3.5-year-old girl with bilateral congenital glaucoma as well as aniridia, lens coloboma, nystagmus, and strabismus had been followed up since birth. Medical treatment did not result in the desired intraocular pressure improvement. An Ahmed glaucoma valve was implanted bilaterally. In a follow-up visit at 2 years of age, there were complaints of redness with watery discharge in the right eye. A biomicroscopic evaluation revealed tube erosion of the conjunctiva. The eroded area was dissected from the surrounding tissue and the area was closed using the new double-layer amnion membrane technique. After the surgery, the intraocular pressure was normal. Subsequent follow-up indicated that the erosion defect was closed and stabilized. The double-layer amniotic membrane technique can be used successfully in cases of conjunctival tube erosion. To the authors' knowledge, this is the first published pediatric case report of using the novel technique of amniotic membrane transplantation for tube erosion.

In the approximation of a thin double layer, simple dependences of the acoustic fields excited in an electrokinetic electroacoustic transducer on the velocity of the Helmholtz—Smolukhovsky osmotic movement are obtained. From the dependencies it follows that in the absence of losses, when the nonlinearity of the fluid motion equation does not yet affect and there is no turbulent mode of fluid motion in the transducer body, the magnitudes of the amplitudes of the acoustic velocity and pressure linearly depend on the magnitude of the Helmholtz—Smolukhovsky electroosmotic motion velocity.

Magnesium alloys have found widespread application as engineering and functional materials in automobile, aerospace, electronics, and biomedical industries. However, these alloys are susceptible to corrosion, and the development of new anticorrosion coatings on Mg alloys surface is urgently needed. In this work, pristine and doped double-layer silane coatings were applied to the AZ91D Mg alloy surface in order to improve its corrosion resistance properties in a 3.5% NaCl solution. The doped silane coatings consisted of KH-550 as the bottom layer and Nd(NO3)3-doped bis-(γ-triethoxysilylpropyl)-tetrasulfide (BTESPT) as the top layer. The effect of Nd(NO3)3 concentration on the corrosion inhibition properties of silane coatings was studied, and the highest corrosion resistance was achieved when the Nd(NO3)3 concentration was 5 × 10−3 mol/L. Compared to the pristine coating, the doped coating had enhanced hydrophobicity with a water contact angle of 108° and, to the best of our knowledge, one of the lowest corrosion current densities (1.51 × 10−2 μA/cm2) reported to date for treated AZ91D. These significant improvements were attributed to the presence of the Si-O-Nd network in the doped coating, leading to the uniform and homogeneous nature and excellent anticorrosion properties of Nd-doped silane coating.

The FeZnO (iron zinc bimetallic oxide) was synthesised using the ultrasound-assisted method and further converted into FeZnOAC (iron zinc bimetallic oxide-doped activated carbon) by treating it with activated carbon. As developed FeZnOAC is effectively used for the adsorption of Fuchsine dye from an aqueous dye solution. A 200 mg of FeZnOAC was sufficient for the rapid removal of Fuchsine (>97.64%) dye. The kinetic adsorption data is well fitted with a pseudo-second-order model. The Langmuir isothermal model shows a high regression coefficient (R2) than the Freundlich with a Qmax of 333.33 mg g−1. The dye adsorption at varying temperatures (i.e. 298–318 K) was based on a multi-layered statistical physics model. The n value (n

The outer layer of a double-layer shaped charge (DLSC) adopts high-detonation-velocity explosive (HE) and the inner layer adopts low-detonation-velocity explosive (LE). Compared with ordinary shape...

The assembly of colloidal particles into ordered structures is of great importance to a variety of nanoscale applications where the precise control and placement of particles is essential. A fundamental understanding of this assembly mechanism is necessary to not only predict, but also to tune the desired properties of a given system. Here, we use constructal theory to develop a theoretical model to explain this mechanism with respect to van der Waals and double layer interactions. Preliminary results show that the particle aggregation behavior depends on the initial lattice configuration and solvent properties. Ultimately, our model provides the first constructal framework for predicting the self-assembly of particles and could be expanded upon to fit a range of colloidal systems.

The clay platelets are negatively charged, and hence, the behavior of clays is physicochemical in nature. The clay–pore liquid interaction depends upon pore medium chemistry, which is a function of many factors. Dielectric constant of the pore medium is one such important factor. The clay swelling is considered to be explained by the Gouy–Chapman theory of diffuse double layer. This paper intends to study the effect of dielectric constant of the pore fluid on the equilibrium sediment volume in light of diffuse double-layer equation of the Gouy–Chapman theory. It has been illustrated that the Gouy–Chapman theory cannot explain the equilibrium sediment volume behavior of montmorillonite and kaolinite clay minerals satisfactorily. It is also brought out that the equilibrium sediment volume behavior of these two clay minerals is quite opposite to each other.

Diffusiophoresis of a charge regulated spherical polyelectrolyte nanogel (PE) due to an externally imposed ionic concentration gradient is considered. The immobile charge density of the nanogel develops through the association/dissociation reactions of their inorganic functional groups. The nanogel is ion and fluid permeable with dielectric permittivity different from that of the surrounding electrolyte medium. This difference in dielectric permittivity creates an ion partitioning due to the difference in self energy of ions. The Nernst–Planck equation for ion transport and the Poisson equation (PNP) for the electric field are modified to take into account the ion partitioning effects. The diffusiophoresis mechanism is governed by the electrophoresis generated by the induced electric field and chemiphoresis develops due to the mitigation of counterions across the double layer of the nanogel. In addition, the convection dominated double layer polarization and the counterion condensation as well as the electroosmotic flow created by the gel immobile charge play a role in the diffusiophoresis. All these effects are incorporated through the modified PNP equations coupled with the Navier–Stokes equations. The governing equations in their full form are solved numerically through a control volume approach. Present computed solutions for the limiting cases are in good agreement with the existing solutions based on the first-order perturbation analysis. In order to illustrate the diffusiophoresis mechanism we have measured the induced electric field and effective charge density of the PE and analyzed its dependence on several electrokinetic parameters. The contribution due to chemiphoresis is low for PE compared to a rigid colloid. For a highly permeable PE the diffusiophoretic velocity increases and approaches a saturation for higher range of the PE fixed charge density. The ion partitioning effect depletes counterions in PE to manifests its diffusiophoretic velocity. The diffusiophoretic velocity of PE for pH > IEP is higher than the case for which pH

A new double-layer, pH-sensitive, composite hydrogel sustained-release system based on polysaccharides and synthetic polymers with combined functions of different inner/outer hydrogels was prepared. The polysaccharides inner core based on sodium alginate (SA) and carboxymethyl cellulose (CMC), was formed by physical crosslinking with pH-sensitive property. The synthetic polymer out-layer with enhanced stability was introduced by chemical crosslinking to eliminate the expansion of inner core and the diffusion of inner content. The physicochemical structure of the double-layer hydrogels was characterized. The drug-release results demonstrated that the sustained-release effect of the hydrogels for different model drugs could be regulated by changing the composition or thickness of the hydrogel layer. The significant sustained-release effect for BSA and indomethacin indicated that the bilayer hydrogel can be developed into a novel sustained delivery system for bioactive substance or drugs with potential applications in drugs and functional foods.

This study proposes using double-layer wire-grid structures to create narrow-band, perfect plasmonic absorbers, which depend on polarization, for the short-wavelength visible and near-ultraviolet regions of the electromagnetic spectrum. A rigorous coupled-wave analysis reveals that the maximum absorption attained using Ag and Al is ~90% at 450 nm and 375 nm. Experiments using Ag yielded results similar to those predicted by simulations. These results demonstrate that narrow-band perfect plasmonic absorbers, which depend on the polarization, can be realized at 450 nm and 375 nm using Ag or Al.

The performance of prism-based surface plasmon resonance sensor utilizing new sensing configuration composed of thin metallic (Al–Au) film coated with a thin layer of BaTiO3is investigated theoretically based on angular interrogation method. It is observed that optimizing the thickness of bimetallic (Al–Au) and BaTiO3 layers, the sensitivity of the sensor improved greatly and still can maintain its minimum reflectivity and linewidth of the SPR reflectivity curve. We also observed addition of dual layer of graphene on BaTiO3 further enhanced the sensitivity. The sensitivity of the proposed sensor is found to be 227 deg/RIU, and the FWHM of resonance curve is observed to be 4.47 deg for the thickness of 28 nm of Al, 8 nm of Au and 10 nm of BaTiO3added with double layer of graphene.

Double-layer solid polymer electrolytes (DLSPEs) comprising one layer that is stable toward lithium metal and one which is stable against a high-voltage cathode are commonly suggested as a promising strategy to achieve high-energy-density lithium batteries. Through in-depth EIS analysis, it is here concluded that the polymer–polymer interface is the primary contributor to electrolyte resistance in such DLSPEs consisting of polyether-, polyester-, or polycarbonate-bad SPEs. In comparison to the bulk ionic resistance, the polymer–polymer interface resistance is approximately 10-fold higher. Nevertheless, the interfacial resistance was successfully lowered by doubling the salt concentration from 25 to 50 wt % LiTFSI owing to improved miscibility at the interface of the two polymer layers.

Gold, as the noblest metal, is an appropriate model electrode to study electrochemical double layers. This study examines the frequency dispersion of the double layer of polished gold electrodes in perchloric acid with impedance spectroscopy under amplitude, electrolyte concentration, and potential variation. The dynamic perturbation of the double layer equilibrium by impedance measurements shows a constant phase (CP) response (phase angle of approximately −75°), which is responsible for a frequency dispersion of the capacitance. The response is almost independent of the excitation amplitude, for which the CP behavior is ascribed to resistive–capacitive (RC) contributions of the electric field-driven ion separation instead of the previously reported diffusion-limited adsorption processes. The RC character of the double layer in combination with the electrolyte resistance is accompanied by a relaxation that can damp the ion movement and the related ion separation. At the relaxation frequency, the capacitance is found to be independent of the electrolyte concentration, which is attributed to a constant ratio of the contributions of damped ion movement and dielectric polarization of water molecules.

Copper (Cu) is a unique electrocatalyst, which is able to efficiently oxidize CO at very low overpotentials and reduce CO2 to valuable fuels with reasonable Faradaic efficiencies. Yet, knowledge of its electrochemical properties at the solid/liquid interface is still scarce. Here, we present the first two-stranded correlation of the potential of zero free charge (pzfc) of Cu(111) in alkaline electrolyte at different pH values through application of nanosecond laser pulses and the corresponding interfacial structure changes by in situ electrochemical scanning tunneling microscopy imaging. The pzfc of Cu(111) at pH 13 is identified at −0.73 VSHE in the apparent double layer region, prior to the onset of hydroxide adsorption. It shifts by (88 ± 4) mV to more positive potentials per decreasing pH unit. At the pzfc, Cu(111) shows structural dynamics at both pH 13 and pH 11, which can be understood as the onset of surface restructuring. At higher potentials, full reconstruction and electric field dependent OH adsorption occurs, which causes a remarkable decrease in the atomic density of the first Cu layer. The expansion of the Cu–Cu distance to 0.3 nm generates a hexagonal Moiré pattern, on which the adsorbed OH forms a commensurate (1 × 2) adlayer structure with a steady state coverage of 0.5 monolayers at pH 13. Our experimental findings shed light on the true charge distribution and its interrelation with the atomic structure of the electrochemical interface of Cu.