Multilayer System Research Articles

Magnetic Properties and Hysteresis Loops of the Mixed Spin-1/2 and Spin-3/2 Blume Capel Model on a Multilayer Square Lattice

This paper is a study of a multilayer system with mixed spins S = 1/2 and spin S = 3/2 by the Blume Capel model using Monte Carlo simulation. The phase diagrams (at T = 0 and T ≠ 0) as well as the total magnetization have been determined. The critical temperatures have been deduced from the different values of the system parameters, namely the exchange interactions JB, the crystal field ∆ and the numbers of layers of the system NA and NB. It became apparent that the system presents both the first and second-order transitions. In addition, we see the appearance of one of the serval phenomena which is compensation behavior. Moreover, the hysteresis behavior present single and multiples hysteresis loops for well-determined values. Finally, our results are compared with the other theoretical and experimental works.

Towards the Optimization of a Photovoltaic/Membrane Distillation System for the Production of Pure Water.

The production of pure water plays a pivotal role in enabling sustainable green hydrogen production through electrolysis. The current industrial approach for generating pure water relies on energy-intensive techniques such as reverse osmosis. This study unveils a straightforward method to produce pure water, employing real-world units derived from previously simulated and developed laboratory devices. This demonstrated system is cost-effective and boasts low energy consumption, utilizing membrane distillation (MD) driven by the waste heat harnessed from photovoltaic (PV) panels. In a previous study, modeling simulations were conducted to optimize the multi-layered MD system, serving as a blueprint for the construction of prototype devices with a suitable selection of materials, enabling the construction of field-testable units. The most efficient PV-MD device, featuring evaporation and condensation zones constructed from steel sheets and polytetrafluoroethylene (PTFE) membranes, is capable of yielding high-purity water with conductivity levels below 145 μS with high flux rates.

Enthalpy-Driven Self-Healing in Thin Metallic Films on Flexible Substrates.

Self-healing microelectronics are needed for costly applications with limited or without access. They are needed in fields such as space exploration to increase lifetime and decrease both costs and the environmental impact. While advanced self-healing mechanisms for polymers are numerous, practical ways for self-healing in metal films have yet to be found. A concept for an autonomous intrinsic self-healing metallic film system is developed, allowing the healing of cracks in metallic films on flexible substrates. The concept relies on stabilizing metastable thin films with high mixing enthalpy via segregation barriers. This allows the films to possess autonomous intrinsic self-healing capabilities triggered by cracking at temperatures not detrimental to flexible microelectronics. The effect will be shown on metastable Mo1-xAgx thin films, stabilized via a Mo segregation barrier. Without a segregation barrier, the system is known to exhibit spontaneous Ag particle formation on the surface. This property is controlled and directed to heal cracks and partially restore the electro-mechanical properties of the multilayer system. This mechanism opens up the field of self-healing thin metallic films that could profoundly impact the design of future microelectronics.

Comment on “Fast and accurate electromagnetic field calculation for substrate-supported metasurfaces using the discrete dipole approximation”

Abstract The article entitled “Fast and accurate electromagnetic field calculation for substrate-supported metasurfaces using the discrete dipole approximation (DDA)” written by W. Liu and E. McLeod presents a method for computing the Green function in presence of a substrate or multilayer in an efficient way. Unfortunately, the proposed method has been known for more than twenty years and significantly ameliorated. It can be found in its optimized version in some open-source DDA codes. In this comment, we recall the different approaches (and related papers) addressing the computation of the Green function of a multilayered system. We show that they address all the points raised by Liu and McLeod in their paper and provide more efficient solutions to their computational issues.

Efficient desalination in fluorinated multilayered covalent organic framework: Tunning the energy landscape inside the nanochannel

The design and construction of advanced nanochannels can significantly enhance the performance of reverse osmosis (RO) membranes in desalination, offering potential solutions to the severe freshwater shortage crisis. In this study, we investigated the desalination performance of nanochannels formed by multilayered covalent organic frameworks (COF) that had undergone various types of chemical functionalization, through nonequilibrium molecular dynamics simulations. Our data reveals that fluorination of the nanochannel results in the most impressive desalination performance, as evidenced by significant improvements in both water permeability (increasing from 39.1 to 100.1 L cm−2 day−1 MPa−1) and salt rejection (rising from 91.9 % to 97.1 %). Especially, in multilayered systems, fluorinated nanochannel mitigates the typical decline in water permeability with increasing membrane thickness. For the working mechanism, the free energy analysis indicates that fluorination contributes to a smooth energy landscape for water molecules inside the nanochannel, reducing their interaction with the nanochannel, which results in a more dispersed arrangement of water molecules with fewer hydrogen bonds and a significantly enhanced water velocity, thus facilitating their fast and unobstructed permeation. Therefore, this study offers a promising semipermeable membrane for high-efficiency desalination, achieved through fluorination. It also demonstrates an indicative approach for advanced channel design through fluorination engineering.

A novel acid-responsive polymer coating with antibacterial and antifouling properties for the prevention of biofilm-associated infections

Chronic infections caused by the pathogenic biofilms on implantable medical devices pose an increasing challenge. To combat long-term biofilm-associated infections, we developed a novel dual-functional polymer coating with antibacterial and antifouling properties. The coating consists of N-vinylpyrrolidone (NVP) and 3-(acrylamido)phenylboronic acid (APBA) copolymer brushes, which bind to curcumin (Cur) as antibacterial molecules through acid-responsive boronate ester bonds. In this surface design, the hydrophilic poly (N-vinylpyrrolidone) (PVP) component improved antifouling performance and effectively prevented bacterial adhesion and aggregation during the initial phases. The poly (3-(acrylamido) phenylboronic acid) (PAPBA, abbreviated PB) component provided binding sites for Cur by forming acid-responsive boronate ester bonds. When fewer bacteria overcame the anti-adhesion barrier and colonized, the surface responded to the decreased microenvironmental pH by breaking the boronate ester bonds and releasing curcumin. This responsive mechanism enabled Cur to interfere with biofilm formation and provide a multilayer anti-biofilm protection system. The coating showed excellent antibacterial properties against Escherichia coli and Staphylococcus aureus, preventing biofilm formation for up to 7 days. The coating also inhibited protein adsorption and platelet adhesion significantly. This coating also exhibited high biocompatibility with animal erythrocytes and pre-osteoblasts. This research offers a promising approach for developing novel smart anti-biofilm coating materials.

Carrier transport simulations in twisted bilayer and turbostratic multilayer graphene systems

The effects of inserting a twisted bilayer graphene (tBLG) between turbostratic graphene layers and a SiO2 substrate on the transport properties are investigated, to explore the possibility that using a tBLG could be an effective way to screen the potential fluctuations due to the impurities on the substrate. The Fermi velocity in a tBLG changes from that of the pristine graphene depending on the twist angle. In the present study, a parameter α is introduced, which is defined as the ratio of the Fermi velocity in the tBLG to that of pristine graphene, and the transport properties are calculated as a function of α. The self-consistent calculation of the Poisson equation with the Thomas–Fermi approximation is performed for multilayer graphene systems consisting of a tBLG and turbostratic graphene layers, and the potential profiles are incorporated into a Monte Carlo simulator to calculate the drift velocities and mobilities. It is shown that the transport properties of the whole system strongly depend on the parameter α and the number of layers in the system.

Highly efficient 3D-screen printed interfacial solar water desalination system

Interfacial solar steam generation (ISSG) using floating devices is one of the most efficient and simple methods of purifying saline water. In this work, multi-layered solar steam generation systems are fabricated using 3D-screen printing. The printed devices with a uniform layer-by-layer structure contain light-harvesting, thermal insulation, thermal conduction, and water-transfer layers. The graphite (Gr) photothermal layer as an absorber layer is screen printed on the felt substrate with three different 3D patterns, which is isolated by transparent hydrophobic silica aerogel (SA) as a light scattering agent to provide efficient photon capturing and heat localization. Furthermore, to transfer the generated heat to the water proficiently, a copper (Cu) layer is coated on the downside of the absorber layer. The devices with the best performances are introduced by evaluating the effect of the fabricated layers thickness and different configurations. The multi-layered device containing a photothermal layer with SP1-3rd pattern and different thicknesses of SA 32 μm (under Cu), Cu 16 μm, Gr 32 μm, and SA 32 μm (on top of the Gr) shows a steam generation efficiency of 97 %, and water evaporation flux of 1.43 kg.m−2.h−1, which are 86 % higher than the performance of the reference system.

Compositional analysis of multilayered plastic constituents and constituent mixtures using benchtop 1H NMR spectroscopy.

Multilayered plastics are widely used in food packaging and other commercial applications due to their tailored functional properties. By layering different polymers, the multilayered composite material can have enhanced mechanical, thermal, and barrier properties compared to a single plastic. However, there is a significant need to recycle these multilayer plastics, but their complex structure offers significant challenges to their successful recycling. Ultimately, the use and recycling of these complex materials requires the ability to characterize the composition and purity as a means of quality control for both production and recycling processes. New advances and availability of low-field benchtop 1H NMR spectrometers have led to increasing interest in its use for characterization of multicomponent polymers and polymer mixtures. Here, we demonstrate the capability of low-field benchtop 1H NMR spectroscopy for characterization of three common polymers associated with multilayered packaging systems (low-density polyethylene [LDPE], ethylene vinyl alcohol [EVOH], and Nylon) as well as their blends. Calibration curves are obtained for determining the unknown composition of EVOH and Nylon in multilayered packaging plastics using both the EVOH hydroxyl peak area and an observed peak shift, both yielding results in good agreement with the prepared sample compositions. Additionally, comparison of results extracted for the same samples characterized by our benchtop spectrometer and a 500-MHz spectrometer found results to be consistent and within 2wt% on average. Overall, low-field benchtop 1H NMR spectroscopy is a reliable and accessible tool for characterization of these polymer systems.

Discrete heat equation for a periodic layered system with allowance for the interfacial thermal resistance: General formulation and dispersion analysis.

Discrete heat equations for the multilayered periodic systems with allowance for the thermal resistance between the layers and corresponding dispersion relations in ω-k space have been derived and analyzed. The discrete equations imply a finite velocity of thermal disturbances and guarantee the positiveness of the solutions. Analytical expressions for the attenuation distance, and phase and group velocities have been obtained as functions of frequency and thermal resistance between the discrete layers. These functions demonstrate unusual behavior at high frequency compared to the continuum case. Furthermore, the maximum allowed frequency and wave number for the discrete heat equation are limited, whereas there are no such limits in a continuum. The discrete equation contains an infinite hierarchy of continuous partial differential equations, which starts with the Fourier law, proceeds with the hyperbolic equation, the Guyer-Krumhansl (or Jeffreys type) equation, and then with higher-order equations. The partial differential equations with a finite number of terms are only approximations of the discrete equation, which implies that on the ultrashort space and timescales the discrete approach is preferable. This work provides a relatively simple, easy-to-adopt, conceptual tool, together with analytical expressions allowing one to study ultrafast wavelike heat conduction regimes in periodic multilayered metamaterials.

Influence of ferromagnetic interlayer exchange coupling on current-induced magnetization switching and Dzyaloshinskii-Moriya interaction in Co/Pt/Co multilayer system.

This paper investigates the relationship among interlayer exchange coupling (IEC), Dzyaloshinskii-Moriya interaction (DMI), and multilevel magnetization switching within a Co/Pt/Co heterostructure, where varying Pt thicknesses enable control over the coupling strength. Employing Brillouin Light Scattering to quantify the effective DMI, we explore its potential role in magnetization dynamics and multilevel magnetization switching. Experimental findings show four distinct resistance states under an external magnetic field and spin Hall effect related spin current. We explain this phenomenon based on the asymmetry between Pt/Co and Co/Pt interfaces and the interlayer coupling, which, in turn, influences the DMI and subsequently impacts the magnetization dynamics. Numerical simulations, including macrospin, 1D domain wall, and simple spin wave models, further support the experimental observations of multilevel switching and help uncover the underlying mechanisms. Our proposed explanation, supported by magnetic domain observation using polar-magnetooptical Kerr microscopy, offers insights into both the spatial distribution of magnetization and its dynamics for different IECs, thereby shedding light on its interplay with DMI, which may lead to potential applications in storage devices.

Insulating layers in multilayer systems based on F/S

In this work, structures of a superconducting spin valve (SSV) of model ferromagnetic1/superconductor/ferromagnetic2 (F1/S/F2) with insulating layers at the superconductor/ferromagnet interfaces were prepared and studied. The results obtained demonstrate the critical role of insulating layers on the value of the SSV effect. It is impossible to observe the SSV effect without presence of insulating layers in the SSV structure with certain selection of its parameters. The existence of insulating layers and the optimal selection of the thickness of the superconducting layer are critical for observing large SSV effects for the SSV structure of F1/S/F2 model.

Influence of Metal Surface Structures on Composite Formation during Polymer–Metal Joining Based on Reactive Al/Ni Multilayer Foil

Progressive developments in the field of lightweight construction and engineering demand continuous substitution of metals with suitable polymers. However, the combination of dissimilar materials results in a multitude of challenges based on different chemical and physical material properties. Reactive multilayer systems offer a promising joining method for flexible and low‐distortion joining of dissimilar joining partners with an energy source introduced directly into the joining zone. Within this publication, hybrid lap joints between semicrystalline polyamide 6 and surface‐structured austenitic steel X5CrNi18–10 (EN 1.4301) are joined using reactive Al/Ni multilayer foils of the type Indium–NanoFoil. The main objective is to examine possibilities of influencing crack initiation in the foil plane by variation of joining pressure and different metal surface structures with regard to geometry, density, and orientation. Thus, the position of foil cracks is superimposed onto the metal structure and associated filling with molten plastic is improved. Consequently, characterization of occurring crack positions as a function of joining pressure and metal structure, analysis of the composite in terms of structural filling and joint strength, as well as possible causes of crack initiation are evaluated.

Analysis and regulation of driving behavior in the entrance zone of freeway tunnels: Implementation of visual guidance systems in China

In China, visual guidance systems are commonly used in tunnels to optimize the visual reference system. However, studies focusing specifically on visual guidance systems in the tunnel entrance zone are limited. Hence, a driving simulation test is performed in this study to quantitatively evaluate the effectiveness of (i) visual guidance devices at different vertical positions (pavement and roadside) and (ii) a multilayer visual guidance system for regulating driving behavior in the tunnel entrance zone. Furthermore, the characteristics of driving behavior and their effects on traffic safety in the tunnel entrance zone are examined. Data such as the vehicle position, area of interest (AOI), throttle position, steering wheel angle, and lane center offset are obtained using a driving simulation platform and an eye-tracking device. As indicators, the first fixation position (FP), starting deceleration position (DP), average throttle position (TPav), number of deceleration stages (N|DS), gradual change degree of the vehicle trajectory (G|VT), and average steering wheel angle (SWAav) are derived. The regulatory effect of visual guidance devices on driving performance is investigated. First, high-position roadside visual guidance devices effectively reduce decision urgency and significantly enhance deceleration and lane-keeping performance. Specifically, the advanced deceleration performance (AD), smooth deceleration performance (SD), trajectory gradualness (TG), and trajectory stability (TS) in the tunnel entrance zone improve by 63%, 225%, 269%, and 244%, respectively. Additionally, the roadside low-position visual guidance devices primarily target the trajectory gradualness (TG), thus resulting in improvements by 80% and 448% in the TG and TS, respectively. Meanwhile, the pavement visual guidance devices focus solely on enhancing the TS and demonstrates a relatively lower improvement rate of 99%. Finally, the synergistic effect of these visual guidance devices facilitates the multilayer visual guidance system in enhancing the deceleration and lane-keeping performance. This aids drivers in early detection and deceleration at the tunnel entrance zone, reduces the urgency of deceleration decisions, promotes smoother deceleration, and improves the gradualness and stability of trajectories.

Proposal and application of a raised multilayer flooring system and its influences on thermal environments

ABSTRACT This study discusses a raised multilayer floor (RMF) system. The RMF system is characterized by gaps between the slab and flooring material. It has been applied to a wide range of building types in Japan because it is known to excel in acoustic absorption. The thermal performance of the RMF systems was considered to be more efficient than that of a floating floor (FF) system in which a heating panel is attached to a floor slab. However, this has not been sufficiently explored. In this paper, 72-hour in-situ temperature measurement test was performed to compare the thermal performance of the RMF and FF systems. They were applied to two identical rooms in a reinforced concrete (RC) building. The tests were performed under three different heating conditions. There was no heating, air-conditioning heating, or floor heating (FH). The RMF system was found to be more effective than the FF system in terms of FH operation speed, comfort level, energy efficiency, and vertical temperature distribution. The RMF system increased the floor surface temperature about 2°C higher than the FF system. 72-hour FH operation at a 26°C setting resulted in the RMF system reducing energy consumption by approximately 10% than the FF system.

Exploring Sustainable Coating Solutions for Applications in Highly Corrosive Environments

To protect carbon steel from degradation via corrosion, it is usually coated using a multilayer system of paints composed of petroleum-based polymers. The chemical industry is currently moving towards more sustainable chemistry, in which one of the main objectives is to reduce fossil fuel use and the derived raw materials. However, the replacement of petroleum-based raw materials with those that are bio-based is not straightforward since the properties of these new materials are often inferior to the traditional ones. One of the most used resins in primer paints is Diglycidyl ether bisphenol A (DGEBA). This is an epoxy resin synthesized from bisphenol A (BPA), a toxic and carcinogenic petroleum-based compound. This study investigates the substitution of the primer coating in a three-layer coating system with two different types of primer coating formulations, one which is partially bio-based and another that is BPA-free. The corrosion protection effectiveness of these sustainable coatings is assessed not only at the laboratory scale but also in real offshore conditions. Moreover, the adhesion of the different coating systems is evaluated before and after each ageing test. The results reveal that these novel coatings exhibit comparable performance to conventional paints while providing a more sustainable corrosion protection alternative.

Tailoring the Reaction Path: External Crack Initiation in Reactive Al/Ni Multilayers

The influence of intentionally externally induced cracks in reactive Al/Ni multilayer systems is investigated. These cracks affect the reaction dynamics and enable tailoring of the reaction path and the overall velocity of the reaction front. The influence of layer variations onto mechanical crack formation and resulting reaction behavior are investigated. High‐speed camera imaging shows the meandering propagation of the reaction front along the crack paths. Therefore, the mechanical cracking process significantly changes the total velocity of the reaction front and thus offers a possibility to control the self‐propagating high‐temperature synthesis process. It is shown that the phase formation remains unaffected despite the applied strains and cracks. This favorable stability in phase formation ensures predictability and provides insight into the adaptation of RMS for precision applications in joints. The results expand the understanding of mechanical cracking as a tool to influence high‐temperature synthesis in reactive multilayer coatings and provide an opportunity to expand the range of applications.

Perovskite/organic tandem device to realize light detection and emission dual function

Developing highly integrated smart optoelectronic systems is vital to modern technology, yet critically challenging. This study introduces a tandem device that incorporates an organic photodiode (OPD) and a perovskite light emitting diode (PeLED), enabling simultaneous light detection and emission in one compact device, prepared by all-solution fabrication process. It shows that precise control of interfacial properties plays a critical role in establishing the all-solution processed OPD/PeLED multi-layered dual-function device which is critical for charge transport, recombination, and generation. The integrated structure allows for light detection and emission function selectively by controlling the polarity of the external bias. The optoelectronic performance of the dual-function tandem device is comparable to that of the discrete control OPD and PeLED, i.e., the tandem device achieves a responsivity of 94 mA/W at 850 nm under −1 V and a luminance result of 1319 cd/m2 at 516 nm under 7 V, which is comparable to 101 mA/W and 1983 cd/m2 for the control OPD and PeLED operated under the same conditions. This work demonstrates the promising properties of the monolithically integrated dual-functional device and its potential for application in health monitoring and wearable electronic devices.

Water Hydrogen-Bond Mediated Layer by Layer Alignment of Lipid Rafts as a Precursor of Intermembrane Processes.

Lipid rafts, which are dynamic nanodomains in the plasma membrane, play a crucial role in intermembrane processes by clustering together and growing in size within the plane of the membrane while also aligning with each other across different membranes. However, the physical origin of layer by layer alignment of lipid rafts remains to be elucidated. Here, by using fluorescence imaging and synchrotron X-ray reflectivity in a phase-separated multilayer system, we find that the alignment of raft-mimicking Lo domains is regulated by the distance between bilayers. Molecular dynamics simulations reveal that the aligned state is energetically preferred when the intermembrane distance is small due to its ability to minimize the volume of surface water, which has fewer water hydrogen bonds (HBs) compared to bulk water. Our results suggest that water HB-driven alignment of lipid rafts plays a role as a precursor of intermembrane processes such as cell-cell fusion, virus entry, and signaling.

Toward Design Rules for Multilayer Ferroelectric Energy Storage Capacitors - A Study Based on Lead-Free and Relaxor-Ferroelectric/Paraelectric Multilayer Devices.

Future pulsed-power electronic systems based on dielectric capacitors require the use of environment-friendly materials with high energy-storage performance that can operate efficiently and reliably in harsh environments. Here, a study of multilayer structures, combining paraelectric-like Ba0.6Sr0.4TiO3 (BST) with relaxor-ferroelectric BaZr0.4Ti0.6O3 (BZT) layers on SrTiO3-buffered Si substrates, with the goal to optimize the high energy-storage performance is presented. The energy-storage properties of various stackings are investigated and an extremely large maximum recoverable energy storage density of ≈165.6Jcm-3 (energy efficiency≈93%) is achieved for unipolar charging-discharging of a 25-nm-BZT/20-nm-BST/910-nm-BZT/20-nm-BST/25-nm-BZT multilayer structure, due to the extremely large breakdown field of 7.5MVcm-1 and the lack of polarization saturation at high fields in this device. Strong indications are found that the breakdown field of the devices is determined by the outer layers of the multilayer stack and can be increased by improving the quality of these layers. Authors are also able to deduce design optimization rules for this material combination, which can be to a large extend justify by structural analysis. These rules are expected also to be useful for optimizing other multilayer systems and are therefore very relevant for further increasing the energy storage density of capacitors.