Multilayer Structure Research Articles

Preparation and characterization of functionally antibacterial multi-layer lignin core-shell structure material with adsorption and high efficiency of photocatalysis for Cr(Ⅵ)

Wastewater with chromium is a common heavy metal pollution in industrial pollution, affecting health of human seriously, while adsorption and photocatalysis are efficient for Cr(Ⅵ) removal. The multi-layer lignin core-shell structure materials were prepared with kraft lignin/polydopamine core-shell structure material, using non-covalent bonding to induce the in-situ induction of TiO2. The hydroxyl group of kraft lignin and the amino group of polydopamine provided abundant adsorption active sites with adsorption capacity being 299mg/g at pH of 2. The adsorption process conformed to the Freundlich isotherm model and the pseudo-second-order kinetic model. The removal rate of Cr(Ⅵ) reached more than 99.9% within 10min under simulated solar light with influence of adsorption and photocatalysis. The multi-layer lignin core-shell structure materials presented excellent antibacterial activity, with the inhibition rate against S.aureus and E.coli being 40% under dark conditions and 99% under simulated solar light because h+ or ·OH producing by TiO2. The antibacterial multi-layer lignin core-shell structure materials showed good universality in water pollution treatment.

Enhancing energy storage performance in multilayer ceramic capacitors with (Pb,La)(Zr,Sn,Ti)O3-based antiferroelectric solid solutions

Antiferroelectric dielectrics (AFEs) have gained exponentially soaring attention in pulsed power systems owing to their high-energy storage and power densities. However, simultaneously achieving high recoverable energy density (Wrec) and high energy efficiency (η) remains challenging due to low electric breakdown strength (Eb) and large hysteresis. This work proposes a solid solution strategy based on the composition modification of AFEs to reconcile the contradiction between maximum polarization (Pmax) and Eb while maintaining high η. The high-Eb Pb0.95Ca0.02La0.02(Zr0.93Sn0.05Ti0.02)O3 (PCLZST) was mixed with the low-hysteresis (Pb0.885Ba0.04La0.05)(Zr0.65Sn0.3Ti0.05)O3 (PBLZST) to increase the Eb and induce the polarization saturation of the PBLZST-PCLZST solid solution ceramics. The resulting 60PBLZST-40PCLZST multilayer ceramic capacitors (MLCCs) demonstrate a favorable Wrec of 13.1 J cm-3 and a high η of 94.2% at 570 kV cm-1. The synergistic design of composition and multilayer structure provides a versatile approach to optimize the energy storage performance of AFE dielectric capacitors.

A simple electrochemical immunosensor based on MWCNTs-COOH/Fc-COOH@CoAl-LDH, nanocomposite for sensitive detection of the tumor marker CA724

A novel label-free electrochemical immunosensor for the ultrasensitive determination of cancer antigen (CA724) was developed using a novel composite of CoAl layered double hydroxides (CoAl-LDH) and carboxyl-functionalized multiwall carbon nanotubes (MWCNTs-COOH) as platform and ferrocenecarboxylic acid (Fc-COOH) as signal label. The MWCNTs-COOH/Fc-COOH@CoAl-LDH composite was prepared by a convenient and simple one-step ultrasonic method, and various characterization techniques consisting of scanning electron microscopy (SEM), transimission electronic microscopy (TEM), TEM-Mapping, fourier transform infrared (FT-IR), X-ray diffraction (XRD) and X-ray photoelectronic energy spectrum (XPS) were applied to study the size and morphological features. Due to its large specific surface area and multilayer structure, the CoAl-LDH can be post-doped to embed a large amount of signal probe to realize the amplification of the internal reference signal Fc. In addition, the higher conductivity of MWCNTs-COOH compensates for the deficiency of CoAl-LDH, which effectively strengthened the electron transfer efficiency of electrochemical signaling substances. The optimal experimental conditions were detected to be 2.5 mmol of Fc-COOH, 4.0 mg/mL of concentration, pH 6.0, incubation time of 40 min, and incubation temperature of 37 ℃. Under optimal conditions, the fabricated sensor exhibits linearity in a wide dynamic range covering the physiological concentration, from 0.001 to 100 U/mL and the limit of detection (LOD) was 0.03962 mU/mL, the calibration equation is stated as △I = 7.76363 log10CCA724 + 40.50351 (R2 = 0.99674). The sensor is successfully detects trace levels of CA724 in human serum with excellent recovery rates ranging from 100.52 %-102.30 %, proving the synergy of MWCNTs-COOH/Fc-COOH@CoAl-LDH as a promising platform for electrochemical sensing for clinical detection of other disease markers.

Optimization of C-like sandwich wall structure for high microwave transmission

A multilayered structure of five planar slabs ((Glass epoxy/PU Foam/Vacuum/PU Foam/Glass epoxy) was investigated for broadband microwave propagation. In this study, theoretical calculations of the transmittance, reflectance and absorbance characteristics of the multilayer structure were carried out using the ABCD transfer matrix method, and numerical calculations were obtained using the COMSOL Multiphysics simulation software. The propagation characteristics were investigated as a function of frequency up to the Ka-band and versus angle of incidence ranging from normal to grazing incidence. The results of the theory and simulation were in excellent agreement. The average transmittance for unpolarized or circularly polarized wave was 97% over the S to the K bands, whereas up to 86% transmission was observed at the end of the Ka-band. Higher than 95% transmission of incident waves with frequency 10 GHz was observed over a wide range of angles of incidence up to 70°, after which the transmittance decreased sharply to zero at a grazing incidence (θ1=90°). The results revealed that the absorbance is negligibly small and the incident energy was either transmitted or reflected. The reflectance for both TE and TM wave modes increased appreciably in the angular range 75°≤θ1≤90° and approached 100% at grazing incidence. The curves of the reflectance versus angle of incidence for representative frequencies in the S and X bands revealed a Brewster-like effect for the TM wave mode, while the reflectance of the TE mode varied monotonically, without showing a minimum characteristic of a Brewster-like reflectionless condition.

One-step synthesis of Z-scheme BiOBr/Bi/BiOI efficient heterojunction photocatalysts and the effect of ascorbic acid

Ternary-component BiOBr/Bi/BiOI composites were successfully prepared by a one-step hydrothermal method under the reducing effect of ascorbic acid. Ascorbic acid not only converts Bi3+ to Bi0 as a reducing agent, but also inhibits the growth of grains and controls the morphology, resulting in a multilayered hierarchical floral structure of the BiOBr/Bi/BiOI composites formed by the assembly of nanosheets dotted with nanoparticles on the surface. The composite has highest photocurrent density, lowest photogenerated electron-hole recombination rate and high specific surface area, and exhibits excellent degradation performance for both single and mixed pollutant systems of tetracycline, rhodamine B and methylene blue. h+ is the most dominant reactive oxygen species in the photodegradation process, while ·OH and ·O2− provide weak auxiliary degradation. A Z-scheme photocatalytic degradation mechanism of BiOBr/Bi/BiOI with excellent photocatalytic performance was proposed.

Vacuum assisted desorption of sodium zirconate sorbent for enhancing cyclic stability in pre-combustion CO2 capture

Sodium zirconate (Na2ZrO3) is a promising material for pre-combustion CO2 capture due to its fast sorption kinetics and excellent cyclic stability at high temperatures under ideal condition (desorption in 100% N2). Still, there is a lack of study on the performance of Na2ZrO3 cyclic capture under harsh condition (desorption in high concentration CO2). In this study, Na2ZrO3 was prepared by wet-mixing and heated-drying, and the difference in the cyclic CO2 capture performance of the sample was compared between desorption under harsh condition and vacuum condition. The crystal structure of Na2ZrO3 was identified during the sorption-desorption cycles. The crystal structure was also modeled and simulated to analyze the reason for the superior capture performance from the monoclinic Na2ZrO3. It was found that the special interlocked and multilayered stacked structure of the monoclinic Na2ZrO3 allowed for high reactivity with CO2. It was found that high temperature solely had little help in the desorption of Na2ZrO3 under harsh condition, but vacuum condition promoted desorption of Na2ZrO3 in high fraction CO2, and vacuum desorption at 1000 °C-1050 °C resulted in Na2ZrO3 with both good capture performance and cycling stability. Vacuum desorption led to more complete reversion of Na2ZrO3 to the monoclinic state, benefiting for CO2 capture. This study attempted to simulate the harsh capture environments of real industrial applications and to explore the possibility of Na2ZrO3 as a carbon capture material for pre-combustion capture.

Excellent Energy Storage Performance of Multi-Alternating-Layer Structured PMMA/PVDF Dielectric Composite at High-Temperature

Polymer dielectric capacitors have high power density and are an integral component of electronic and power device. Currently, the limited energy density restricts their further application. In this research, a novel method was designed to optimize performance of PMMA/PVDF composite via an alternating stacked multi-layer structure. And, the five-alternating-layer of PVDF-PMMA-PVDF-PMMA-PVDF (F-A-F-A-F) composite has excellent dielectric properties, for instance, a better dielectric constant (4.52@1 kHz) and a low dielectric loss (0.034@1 kHz). The discharge energy density (Ue) of it is significantly larger than that of PMMA and PVDF. Particularly, the Ue of F-A-F-A-F composite is increased by 83.0% (from 4.71 J/cm3 to 8.62 J/cm3) with charging-discharging efficiency of 60% at 80 °C. Moreover, the F-A-F-A-F composite achieves an excellent stability after 40,000 cycles. This composite has a wide range of potential applications in the field of traditional dielectric capacitor due to its good energy storage performance and cycle stability.

Influence of the laser power and powder feed rate on the porosity, dilution, and building efficiency of pure copper parts fabricated via directed energy deposition with a blue laser

AbstractWe examined single- and multilayer formations in the directed energy deposition for manufacturing pure copper parts using a blue laser with a wavelength of 445 nm. We investigated the influence of laser power and hatching pitch on the surface quality of single-layer structures as well as evaluated the porosity and dilution of multilayer structures fabricated at various laser powers and powder feed rates using energy-dispersive X-ray spectrometry. In addition, the applicability of the simplified method based on the ratio of the built height and penetration depth to the AM process has been examined, and the predicted elemental content was compared with the results obtained from the SEM–EDS analysis. Based on these findings, a range of building conditions that reduce the dilution, suppress the porosity, and improve the building efficiency of the built parts was established. We found that a good surface quality of the single-layer structure was obtained at laser powers and hatching pitches ranging between 150 and 180 W and 0.4 and 0.5 mm, respectively. A higher laser power and a lower powder feed rate decreased the porosity and increased the building efficiency while promoting dilution with the substrate. At a laser power of 180 W and a powder feed rate of 10 mg/s, the built structure exhibited a minimum porosity of 0.1% and a maximum building efficiency of 36%. Dilution with the substrate was the lowest at a laser power of 180 W and a powder feed rate of 20 mg/s, and the proportion of Cu reached 99.0 wt% at a distance of 200 µm from the built structure–substrate interface. The predict method of the dilution based on the ratio between the built height and penetration depth can be integrated in the AM process despite a low prediction accuracy near the substrate due to the complex mixture in the Fe–Cu system.

Efficient and Stable Quantum‐Dot Light‐Emitting Diodes with Trilayer PIN Architecture

AbstractAlthough the performance of quantum dot light‐emitting diodes (QLEDs) has been greatly improved in recent years, the multilayer device structure has become increasingly complex, limiting the practical application of QLEDs. Here, a novel trilayer PIN QLED with only three functional layers, which are Spiro‐OMeTAD:TFB bulk‐heterojunction (BHJ) hole transport layer (HTL), quantum‐dot emitting layer and ZnMgO electron transport layer is demonstrated. Due to the enhanced hole injection capability and suppressed electron leakage of Spiro‐OMeTAD:TFB BHJ HTL, the trilayer PIN QLED can show an excellent external quantum efficiency (EQE) of 25.1% and an impressive brightness of 299300 cd m−2 at only 8 V, which are significantly higher than those of conventional QLED. Moreover, the device stability is also remarkably improved due to the mitigation of hole accumulation and removal of unstable PEDOT:PSS. By using liquid alloy EGaIn as cathode, a fully solution‐processed vacuum‐free trilayer PIN QLED with a higher EQE of 27.3% can be further realized. The developed trilayer PIN QLEDs, with better performance and fewer functional layers, can promote the commercialization of QLED technology.

Electromagnetic Absorption Mechanism of TPMS‐Based Metastructures: Synergy Between Materials and Structures

Abstract3D metastructure absorbers have gained attention for their lightweight, load‐bearing capabilities, and superior electromagnetic wave absorption. However, the complex interplay between unit cell geometry, material properties, and electromagnetic response is not well understood, hindering the design of high‐performance devices. A multi‐scale model, validated is presented by simulations and experiments, that clarify the relationship between materials, structures, and electromagnetic behavior in 3D metastructures. By systematically investigating strut‐based and sheet‐based structures, volume fraction, unit size, crystal lattice orientation, and density gradient within TPMS‐based unit cells, it is revealed that unit geometry significantly influences electromagnetic field propagation and reflection loss. Specifically, under the same unit size, sheet‐based TPMS metastructures exhibit stronger reflectivity than strut‐based ones, while multilayer structures show the opposite trend. The direct correlation is also further confirmed between geometric symmetry and polarization insensitivity, with orthogonal isotropic superstructures displaying excellent polarization‐insensitive properties. This finding provides a new design principle for achieving robust, angle‐independent absorption in these materials. This work enhances understanding of the structure‐electromagnetic behavior interplay, guiding the design of next‐generation broadband, wide‐angle, and polarization‐insensitive devices.

Design and demonstration of a simple, low-cost transparent solar absorber for glass window applications

Windows are a major source of heat loss from buildings in cold climates. Developing coatings for windows that retain high visible transparency and strongly absorbs solar energy in the near infrared region can help reduce energy consumption and cost for indoor heating. Nanophotonic structures based on metasurface and metamaterials have shown great potential for such applications. Unfortunately, most of the designs proposed so far are difficult to fabricate or expensive. In this work, we report the experimental demonstration of a low-cost alternative based on Ni/SiO2/Ni multilayer structure. The device provides a large increase in temperature under solar illumination while retaining high visible transmission. Our optical and thermal measurements reveal that the performance of the device remains stable over a long period. The combination of low cost, ease of fabrication, good optical and thermal performance, and long-term stability makes it a promising design for passive heating of windows in cold climates.

Quantum-inspired genetic algorithm for designing planar multilayer photonic structure

Quantum-inspired genetic algorithm for designing planar multilayer photonic structure

AI Predictive Analytics for Verifying Pharmaceutical Authenticity and Combating Drug Counterfeiting

A significant worry in recent years has been the counterfeiting of medicines. The distribution and manufacture of fake or falsified drugs are both criminal and harmful to the public's health. The severity of this issue differs significantly from one country to another, primarily due to variations in the adherence to national regulations and processes. Thus, preventing the sale of fake drugs has become an urgent matter, particularly in poor and developing nations. The study presents a new multi-layered validation structure for pharmaceutical authenticity verification that uses Generative Adversarial Networks (GANs), Convolutional Neural Networks (CNNs) and blockchain technology for artificial intelligence predictive analytics. The goal is to tackle the widespread problem of counterfeit drugs. Using GANs to sift through past data, the suggested strategy improves the detection of minor package variations by identifying trends and traits linked to counterfeit drugs. Using the GAN-generated enhanced dataset, a CNN is trained to accurately and specifically categorize drug packaging.Further, the framework uses blockchain technology to provide trustworthy and transparent recordkeeping of drugs in realtime as they move through the supply chain. Increased patient safety directly results from our system's thorough audit trail, which solves the problems of fake medications and regulatory compliance. The suggested approach reduces counterfeit dangers and provides a scalable paradigm for other industries to use when dealing with similar authenticity verification issues, which means it can find more uses in safety-critical fields. The success of the multi-layered validation structure model is evaluated using performance metrics such as accuracy, recall, and F1-score. It achieves a fantastic accuracy rate of over 95%.

THIN FILM METHANE SENSOR BASED ON CARBON COMPOSITE

Today, with the oil and gas industry playing a key role in the global energy sector, issues related to the effective control and detection of methane leaks are becoming an integral part of the strategic tasks of the industry. The article is devoted to the research and development of a thin-film sensor for detecting methane in the air using a carbon composite. The technical result of this study is the creation of a highly sensitive and energy efficient sensor for measuring methane concentration. The basis for the sensitive element is a thin film of a carbon composite, consisting of a polymer, single-wall carbon nanotubes and graphene oxide, with aluminum electrodes. The sensor has a number of advantages, including responding to the presence of methane without the need for heating, the simplicity of the sensitive material preparation process, and low cost. The ability to quickly start small-scale production, simplified manufacturing due to the use of only one pair of electrodes, as well as increased energy efficiency due to the absence of the need for heating are also positive characteristics of this device. The study presents the results of manufacturing the sensor, including the steps of cleaning the surface of the substrate, creating a shadow mask, spraying electrodes, forming a thin film of the composite by centrifugation, as well as analyzing the microstructure of the sensor using an atomic force microscope. Also presented are data on obtaining multilayer structures of thin-film resistive sensors based on a polymer matrix nanocomposite, single-wall carbon nanotubes and graphene oxide, including the process of creating electrodes. This study is important for the development of methane monitoring methods in the oil and gas industry and other industrial areas, offering promising technical solutions to ensure environmental and economic sustainability of production.

Analytical Approach of three-dimensional Flawed Multilayered Structure for EC Inspection

This article is devoted to the development of two current source models for the analysis of 3D electromagnetic phenomena in a conductive part of spherical geometry based on the second-order magnetic vector potential method for eddy current nondestructive testing (ECNDT). The first model, for a homogeneous single-layer sphere, allows the analytical calculation of all electromagnetic quantities in the charge. The second allows to treat in addition to the three-dimensional aspect of the problem, the heterogeneity of the charge (with several layers of different conductivities). An investigations using a multifrequency system have shown better results in detection of small cracks. The observations take about the calculation of normalized impedance based on dissipate energy and Joule losses in conductive material.

Developing computational and experimental models of heat transfer through multi-layered textile structures

Object signature management is a critical and urgent task that helps conceal and restrict the detection of contemporary optoelectronic systems. The design of thermal camouflage textiles and material solutions constitute a significant scientific area, however publications in this area are restricted because of military competitiveness and technological secrecy. Research on thermal camouflage materials has drawn interest both domestically and internationally for a variety of purposes, especially in military applications. Multi-layered Textile Structures (MTS) is a material with several advantages, such as its simple structure, capacity to combine many different materials with many different qualities, and great applicability. The article includes a model of computation and simulation of heat transfer through multi-layer textiles, as well as tests to assess the heat shielding effect and heat radiation energy of some samples of multi-layer textiles made of domestic materials. The initial computational and experimental results constitute an important foundation for further research and application of multi-layered textile structures.

Multi-scale finite element analysis of laser-assisted forming of CF/PEEK composite corner structures

Laser-assisted forming can significantly increase the forming efficiency of thermoplastic composites. However, when forming CF/PEEK curved corner structures using laser-assisted forming, bending spring-back generated by the prepreg tape constrains the shape accuracy of the component. The bending deformation of unidirectional resin matrix composite materials is highly nonlinear. In this study, a multi-scale finite element method is used to obtain the bending properties of CF/PEEK composites for bending spring-back phenomenon of thermoplastic composite samples and predict the spring-back angle of CF/PEEK corner structures fabricated via laser-assisted forming. The average material properties were first calculated using RVE. Following this, a mesoscale model was developed to analyze kink deformation of the composite. Finally, the macroscopic prepreg bending spring-back was calculated. It was determined that the main mechanism of corner forming corresponds to the occurrence of a fiber kinking phenomenon on the interior of the corner. Furthermore, spring-back deformation is caused by residual stresses resulting from insufficient fiber kinking. The accuracy of the simulation results is verified via corner forming experiments. This study contributes to a deeper understanding of the spring-back mechanisms of laser-assisted forming of corner structures and provides a theoretical guidance for precision forming of multilayer thermoplastic composite bent structures.

A Bottom-Up Approach to Assemble Cell-Laden Biomineralized Nanofiber Mats into 3D Multilayer Periosteum Mimics for Bone Regeneration.

The creation of complex multilayer periosteal graft structures is challenging. This study introduced a novel bottom-up approach to assemble cell-laden nanofiber mats into a three-dimensional (3D) multilayer periosteum mimic, successfully replicating the hierarchical complexity of the natural periosteum. These nanofiber mats, which were fabricated by electrospinning, surface modification, and stimulated body fluid (SBF) immersion, are composed of nanoscale polycaprolactone (PCL) fibers coated with a mineralized collagen layer along the fiber orientation. They closely resembled the natural periosteal matrix, thereby promoting osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) in vitro. The biomimetic periosteum, constructed via layer-by-layer assembly, offered advantages such as a multilayer nanofibrous structure, controlled cell distribution, a reservoir for osteoprogenitors, and enhanced pro-osteogenic potential. The rat calvarial bone defect model confirmed its potent bone repair capacity. This study presents an efficient approach to construct tissue-engineered periosteum mimics, holding promise for serving as periosteal grafts in orthopedic applications.

AVG delamination: a cause of early cannulation arteriovenous graft dysfunction in hemodialysis patients

Background A series of cases have reported graft delamination as a rare complication of early-cannulation arteriovenous graft (ecAVG). The unique multilayer structure of ecAVGs contributes to the property of cannulation as early as hours after implantation, but on other hand it takes the risk of graft delamination. However, the underlying mechanism and management of graft delamination as well as its effects on the long-term patency of ecAVGs have not been systemically analyzed. Methodsz A retrospective study was conducted in a cohort of patients who required an ecAVG for hemodialysis (HD) access in our center between April 2017 and December 2021. The characteristics of graft delamination and the outcomes of its different treatments were analyzed. Results A total of 144 ecAVGs were established in 141 end-stage renal disease (ESRD) patients, including 124 (86.1%) Acuseal grafts and 20 (13.9%) Flixene grafts. During follow-up 24.5(11.5, 45.8) months, 11 (7.6%) subjects had graft infection with an incidence of 0.03 patient-year. Thirteen (9.0%) subjects had graft delamination at 9.3(5.0,12.4) months after ecAVG implantation, with an incidence of 0.04 per patient-year. ecAVG delamination was observed in both Acuseal grafts (0.037 per patient-year) and Flixene grafts (0.055 per patient-year). Thrombosis or venous hypertension was the most common complaints. Seven delamination was observed at 1.3 (0.1, 4.2) months after an endovascular procedure. The primary patency, primary assistant patency and secondary patency in delamination group were significantly lower than that in non-delamination group (p < 0.05). Post-procedure primary patency of group A (percutaneous transluminal angioplasty, PTA), group B (stenting) and group C (partial graft replacement, PGR) were 1.3 (0.45,4.22) months, 5.3 (3.05,6.85) months and 8.45 (4.78,14.53) months respectively (p = 0.029). Conclusions Graft delamination was not a rare complication of ecAVGs in this cohort. It significantly reduced the long-term patency of AVGs. PGR might be a more effective therapeutic way than endovascular treatments.

Architecture of the Toxoplasma gondii apical polar ring and its role in gliding motility and invasion

In Toxoplasma gondii, the conoid comprises a cone with spiraling tubulin fibers, preconoidal rings, and intraconoidal microtubules. This dynamic organelle undergoes extension and retraction through the apical polar ring (APR) during egress, gliding, and invasion. The forces involved in conoid extrusion are beginning to be understood, and its role in directing F-actin flux to the pellicular space, thereby controlling parasite motility, has been proposed. However, the contribution of the APR and its interactions with the conoid remain unclear. To gain insight into the APR architecture, ultrastructure expansion microscopy was applied to pinpoint known and newly identified APR proteins (APR2 to APR7). Our results revealed that the APR is constructed as a fixed multilayered structure. Notably, conditional depletion of APR2 resulted in significant impairments in motility and invasion. Electron microscopy and cryoelectron tomography revealed that depletion of APR2 alters APR integrity, affecting conoid extrusion and causing cytosolic leakage of F-actin. These findings implicate the APR structure in directing the apico-basal flux of F-actin to regulate parasite motility and invasion.