Substrate Layer Research Articles (Page 1)

High-throughput sequencing technology was used to systematically analyze the composition, diversity, and dynamic changes of soil microbial communities during the wheat growing season in Lintong, Shaanxi Province. The abundance of bacterial communities significantly increases after the complete planting cycle of wheat, while the fungal community structure was relatively stable. At the phylum level, Proteobacteria, Acidobacteria, Bacteroidetes, and Actinobacteria constitute the dominant bacterial communities. The fungal community was Ascomycota and Zygomycota. The growth process of wheat significantly changes the structural composition of bacterial communities, enhances enzyme activity and biological regulatory functions of bacterial communities, while inhibiting cellular processes and environmental information processing functions. This study revealed the succession pattern of soil microbial communities during the wheat growing season, identified key microbial groups that maintain soil ecosystem functions, and provided an important theoretical basis and practical guidance for the sustainable management of the surface substrate layer in the study area. Bangladesh J. Bot. 54(3): 741-748, 2025 (September) Special

Embedded interlocking membrane interface enables highly stable and water-permeable membrane distillation of hypersaline wastewater.

This study investigates the bond strength of fifteen cement-based adhesive mortars used for expanded polystyrene (EPS) in External Thermal Insulation Composite Systems (ETICS). Field surveys and contractor interviews (170 questionnaires) found that adhesive layer thicknesses in real applications typically range from 15–20 mm and frequently exceed 20 mm, in contrast to the smaller values most often recommended by guidelines and technical instructions. Laboratory testing was conducted using two approaches: the standardized pull-off procedure according to EAD 040083-00-0404 (EAD and EAD′ variants) and an in-house pull-off procedure designed to reflect practical conditions of substrate type (concrete slab, silicate block), substrate orientation (horizontal, vertical), and adhesive layer thickness (10 and 20 mm). The results showed that adhesive bond strength is strongly influenced by adhesive layer thickness, substrate type, and substrate orientation. Increasing thickness from 10 mm to 20 mm on concrete substrates typically reduced bond strength by about 65–75%, while vertical orientation lowered adhesion to about half of that obtained in horizontal placement. Silicate substrates exhibited generally lower bond strength but higher variability, occasionally with ratios above unity due to their greater porosity. In some configurations, detachment occurred already during specimen preparation, underlining the variability of performance. The combined effect of increased thickness and vertical orientation on concrete substrates reduced adhesion by about 85% compared to the 10 mm horizontal baseline, highlighting the severity of unfavorable application conditions, whereas on silicate blocks, the effect was weaker but accompanied by large variability. The findings indicate that adhesive layer thickness has a stronger impact on bond strength than orientation and that substrate properties play an important role. The study provides a comparative perspective on current and alternative testing approaches, revealing significant differences in the results. The author’s testing method makes it possible to account for, in laboratory conditions, primarily the geometric shape and orientation of samples that are close to the actual form of adhesive mortar application in real insulation installations. This allows for the assessment of the properties of mortars and substrates that were not exposed under the conditions of current testing methods. The above provides a basis for further discussion on the inclusion of realistic application conditions in the evaluation of adhesive mortars used for bonding thermal insulation in ETICS, and for the validation assessment of an additional testing method, which is currently of an experimental nature.

Abstract Micro‐nano technology and material science have rapidly evolved, and they lead to the emergence of metasurface. However, there are scarce studies on multi‐channel metasurface to generate orbital angular momentum (OAM) and grayscale image (GI) simultaneously. In this work, the metasurface introduces Malus’ law and spin decoupling to modulate terahertz wavefronts. The designed metasurface consists of the following layers from top to bottom: VO 2 patches, silica spacer, gold patches embedded in the VO 2 layer, silica spacer, and gold substrate. For high‐conductivity VO 2 exhibiting a metallic state, the VO 2 metasurface achieves a vortex beam (VB) with topological charge (TC) of l = 1 under right‐handed circularly polarized (RCP) incidence, and it obtains a VB with a gradient phase and under left‐handed circularly polarized (LCP) incidence. Meanwhile, GI B is observed in the near field under y‐polarized incidence. For low‐conductivity VO 2 exhibiting an insulating state, the gold structure embedded in the VO 2 film takes control of the electromagnetic wave. Metasurface obtains a VB with a gradient phase and in the LCP channel, and it achieves a VB with in the RCP channel. Simultaneously, GI A is shown in the near field under y‐polarized incidence. The vast potential of metasurface for applications in imaging and information processing is demonstrated.

Wearable electronics have become a hot research field of next-generation electronics. Despite significant progress in the advancement of wearable electronics, powering these devices with sustainable energy sources and equipping them with special functions remain formidable challenges. Herein, a multifunctional all-nanofiber-based TENG prepared by a simple electrospinning technique is reported, which exhibits good biodegradability, antibacterial activity, UV-protective, flame retardant properties, and hydrophobicity for human motion sensing and biomechanical energy harvesting. This TENG is fabricated by sandwiching a silver nanowire (AgNW) between a sodium alginate (SA) nanofiber membrane-based triboelectric layer and a modified multifunctional substrate layer. Due to the added poly(ethylene oxide) (PEO) and BaTiO3 nanoparticles (BTO) in the SA nanofiber membrane, the output voltage and transferred charge of the TENG are increased by about 4.95 and 3.89 times, and it exhibits a high output power density of 654 mW m-2. Additionally, after modification with phytic acid, octadecylamine, and TiO2 nanoparticles, the nanofiber membrane exhibits special properties, such as UV-protective, hydrophobicity, flame retardancy, antibacterial capabilities, and degradability. Finally, the constructed TENG device is utilized to monitor various human motions in a self-powered manner and harvest energy from body movements to power wearable sensors. Given the outstanding features, the fabricated TENG paves a new and practical pathway to develop next-generation wearable electronics.

The controllable nonreciprocal propagation of light is an intensively investigated field of optics, with studies motivated both by fundamental questions and possible telecommunication applications. So far, polarization-independent, switchable one-way transparency has been demonstrated only at certain resonances of multiferroic crystals at cryogenic temperatures and in high magnetic fields, limiting the practical implementation of this effect. Here, as an alternative approach, we present the one-way transparency of an artificial layered structure consisting of split-ring metamaterial and magnetic substrate layers interacting in the dynamic regime. As evident from our quasioptical experiments in the GHz frequency range, this unique combination breaks time and space inversion symmetries in external magnetic field. The ease of tuning the dynamic response and the possibility of controllable one-way transparency make this approach promising for real-world applications.

Abstract To enhance the spectral signal intensity and stability of LIBS for detecting trace elements in soil, a GO adsorption conversion mechanism is proposed. The experiment compared the enhancement effects of three substrates—glass plate, graphite plate, and GO adsorption layer—on metal elements such as Ni, Sr, and Ba in soil. The surface enhancement mechanisms of different substrates were analyzed from three perspectives: ablation morphology, thermal conductivity, and adsorption energy. It was concluded that a smooth substrate surface facilitates uniform solute distribution, and an increase in the thermal conductivity of the substrate material enhances the signal and enlarges the plasma morphology. The optimal soil-to-nitric acid ratio in the solid-liquid-solid conversion mechanism was determined to be 1:1, with a nitric acid concentration of 1 mol/L. The GO adsorption layer substrate demonstrated the best enhancement effect, with spectral intensities of Ni, Sr, and Ba enhanced by 3.4, 1.8, and 8.4 times, respectively, compared to the glass glass. The limits of detection (LOD) reached 3.148 mg/L, 0.578 mg/L, and 0.342 mg/L, with relative standard deviations (RSD) of 5.4%, 6.8%, and 8.5%, respectively. This indicates that the solid-liquid-solid conversion mechanism using the GO adsorption layer can effectively enrich metal elements in soil, enhancing the spectral signal and stability of LIBS in detecting trace elements while significantly lowering the detection limits. This approach provides a new strategy for the accurate measurement of trace elements in soil samples using LIBS.

This study addresses the durability issues of barcode substrates for photovoltaic (PV) modules under extreme conditions such as high temperature, high humidity, and intense ultraviolet (UV) radiation. A three-layer structured barcode substrate with high-temperature resistance and anti-aging properties was developed, and the die-cutting process was optimized. The three-layer structure consists of a polyethylene terephthalate (PET) substrate layer, a polyimide (PI) anti-aging layer, and a wear-resistant coating. The synergistic effect of these layers significantly enhances the substrate’s temperature resistance and anti-aging performance. Experimental results indicate that after 100 thermal cycles, the tensile strength retention rate of the three-layer structured substrate reaches 92%, much higher than the 65% of traditional PET substrate. After 1000 hours of UV irradiation, the color difference (ΔE) is only 1.5, compared to the 4.0 of traditional PET substrate. Following the optimization of the die-cutting process, the burr rate was reduced from 8% to 0.5%, and the material utilization rate increased from 82% to 95%. In the pilot application at Mingyang Smart and the long-term testing in desert power stations, the three-layer structured barcode substrate demonstrated excellent performance, with a barcode integrity rate of 98%, significantly higher than the 70% of traditional PET substrate. This study provides significant technical support for the development of barcode substrates for PV modules, promoting the high-quality development of the PV industry.

Modern semiconductor device technology expands to new application fields and increasing integrability even to hybrid system approaches. Thus, membrane technologies emerge to be a new standard for light-emitting devices as well. However, the fabrication of membranes often results in a shift of the emission wavelength of the active region compared to the as-deposited structure, especially when containing quantum dots (QDs). In this study, we investigate the wavelength shift of an AlGaInP heterostructure with InP QDs during the GaAs substrate removal step. For this, the substrate of a fivefold InP QD layer is selectively etched in such a way that a single sample provides areas with different remaining substrate thicknesses in a range within 1 μm. With photoluminescence measurements, a continuous blueshift of the emission spectrum of the QD ensemble can be observed. We explain these findings by the change of the strain within the entire structure, which impacts the confinement energies within the QDs.

Many concrete structures require strengthening or repair and a significant method of strengthening the Reinforced Concrete (RC) members is to add a concrete jacket. A type of concrete known as Slurry-Infiltrated Fiber Concrete (SIFCON) has come into use. SIFCON is a unique form of Fiber-Reinforced Concrete (FRC) known for its superior mechanical properties. The effectiveness of upgrading the RC members through jacketing depends on several factors, the most important of which is the bond performance between the substrate and overlay layers. This study examined how various factors influence the bonding performance between the SIFCON overlay and the Normal Strength Concrete (NSC) substrate. The research investigated the effects of surface preparation methods, types of bonding agents, and steel fiber geometry. Three tests were conducted to evaluate the bond strength: the Slant Shear Test (SST), Tensile Bond Test (TBT), and Flexural Bond Test (FBT). The surface preparation methods ranked from best to worst as follows: Grinding (G), Sandblasting (S), and Diamond Cutting (DC). The increase in the bond strength depended on the type of bonding agent and the surface preparation method. When the failure mode changed from Bond Interface (BI) to both BI and Weaker Concrete (BI-WC) or from BI-WC to WC, the increase was noticeable. If the failure mode shifted directly from BI to WC, the growth was significant. However, if the failure mode remained the same, the increase was minimal.

Evaluating multifunctional performance of green roofs in rainstorm events: The role of modifiers in substrate layer

Agaricus bisporus mushrooms are supplied with water through both apoplastic as well as symplastic routes from distinct substrate layers.

In this paper, a transmitarray antenna is designed and fabricated based on a two-layer aperture-coupled patch unit cell. The unit cell is composed of two layers of dielectric substrate with a simple narrow rectangular aperture between the layers. Through characteristic mode analysis, it is shown that while a single patch on each layer does not provide the 360° phase range required in the transmitarray antenna design, if the same patch is divided into several sub-patches, named metasurface, the 360° phase range is achieved. It is also shown that metasurface sub-patches provide a wide gain bandwidth and high aperture efficiency for transmitarray antennas. In addition, a 13 × 13 metasurface-based transmitarray antenna is designed and fabricated. When using a 3 × 3 metasurface unit cell, the measured -1 dB gain bandwidth is 19% and its measured gain is 25.7 dB at the center frequency of 10.5 GHz, exhibiting 50% overall aperture efficiency.

Two-dimensional (2D) materials and liquid crystals (LCs) originate from opposite ends of the materials spectrum, with both recognized for several sought-after properties. In line with current trends in materials science, LCs have progressively entered the realm of nanocomposites, creating new vistas for LC-based applications. Although there is considerable research on these nano-soft composites, the nano-component has predominantly been of zero- and one-dimensional nature, and integration of 2D materials into the field is an appealing upcoming research area. This review outlines such endeavours, describing the influence of 2D materials on both thermotropic and lyotropic LCs, primarily focussing on the nematic mesophase, the orientationally ordered liquid. Sections on both these LCs begin with the theoretical efforts and experimental findings on several physical properties of the 2D materials forming the LCs, or incorporated into nematics in the bulk and upon confinement in a polymer matrix, or as substrate layers for uniform orientation of the nematic director. Various applications, including the bio-related ones, are also described. Finally, we outline potential pathways along which the domain of 2D materials in LCs might advance by addressing the perceived challenges. The interspersed critical comments on the research reported aim to encourage researchers to enrich the field with comprehensive efforts.

Laser direct energy deposition (LDED) has been widely employed in surface modification and remanufacturing. Achieving high-precision geometries and superior mechanical properties in cladding layers remains a persistent research focus. In this study, an Fe-based alloy was deposited on an AISI 1045 substrate via a wide-beam laser cladding system. Single-track multi-layer samples were prepared with varying z-increment (Zd), interlayer dwell time (TI) and laser scanning speed (V) values. The geometry, microstructure, microhardness and wear resistance of the samples were analyzed. Experimental results showed that an estimated Zd can ensure a constant standoff distance of the laser head and resulting geometric accuracy improvement. Planar grains form at the layer–substrate bonding interface and transition to columnar grains adjacently, while dendrites and equiaxed grains are distributed in the middle and top regions of the layer. The coating layer exhibits much better wear resistance and friction properties than the substrate. The cooling rate can be substantially increased by either raising V or prolonging TI, resulting in refined grain structures and enhanced microhardness. Real-time monitoring and controlling the mean cooling rate have been demonstrated to be effective strategies for enhancing cladding layer performance.

The research studied ZnO thin films containing 3 at.% sulphur (S) on silicon (1 μm) through Geant4 simulations for radiation analysis. Analysis of ZnO thin films (400 nm) doped with 3 at.% sulphur (S) on a 1 μm thick silicon substrate through Monte Carlo simulation platform Geant4 considered energy absorption together with particle penetration depth and ionization and secondary electron generation and optical property changes as the study examined different electron radiation energies from 3 keV to 10 keV. The ZnO:S layer absorbed most of the incoming electron energy in the 3-5 keV range which produced increases in defects near the surface while ionization occurred. When electrons used 9-10 keV energies they penetrated the full substrate layer which caused silicon to receive most of the energy absorption. The highest change in parameters occurred at the film-substrate junction when the energy reached 7 keV. All modeling findings demonstrated that the total absorbed energy together with secondary electron production and defect density reaching up to 10⁷ increased rapidly with electron energy acceleration. The decrease in optical properties occurs because defects exist at different depths while energy absorption takes place. Electrical and optical characteristics of ZnO:S/Si can be regulated through electron irradiation procedures according to this research. Results from this study will function as fundamentals for creating sensors and optoelectronic devices and protective coatings which operate effectively under high radiation conditions.

A dual-layer convex patch based on collagen-gelatin/alginate for corneal stroma defects repair and irregular penetrating injuries healing.

The intrinsic aggregation behavior of self-assembled molecules (SAMs) leads to severe heterogeneity or even blankness in the perovskite substrate layer. The direct contact between the bottom surface of perovskite and nickel oxide undergoes a redox reaction, which inevitably leads to perovskite degradation and strengthens the charge transport barrier. Herein, a 1-propenyl-2,3-dimethylimidazole hexafluorophosphate (PDMIMPF6) molecule with bidirectional defect regulation has been developed. PDMIMPF6 binds SAMs and perovskite bilayers to modulate defects of the two as well as to blur the interfacial space. The work function of the SAM layer increases due to repair of the aggregation defect in organic functional molecules, contributing to rapid charge transport and reducing the degradation rate of the perovskite. In addition, the PDMIMPF6 with multifunctional groups has been shown to inhibit FA+ migration and passivate the uncoordinated lead defects through hydrogen bonding and coordination interactions. This molecular adhesive strategy achieves a power conversion efficiency of 25.61% for the PDMIMPF6-treated device. Noticeably, the unencapsulated-device maintaines an initial efficiency of 83.0% at 1200h under maximum power point tracking, and outstanding humidity stability (91.4%) over 2000h.

ABSTRACT Carbon aerogel supported phase change materials (PCMs) can confer multifunctional properties to ordinary PCMs and meet specific requirements in extreme environments. In this study, composite phase change materials (CPCMs) with integrated insulation and thermal conductivity functions were successfully developed through the physical integration of a thermal insulation layer and a thermal conductivity layer. The structurally stable carbonized polyimide (C‐PI)/carbon nanotubes (CNTs) aerogel acts as the thermal conductivity layer substrate. The aerogel obtained from a polyamic acid salt (PAS) composite with carboxymethyl cellulose (CMC) was used for the thermal insulation layer. Then, polyethylene glycol was vacuum‐impregnated into the integrated aerogel to prepare CPCMs with integrated insulation, thermal conductivity, and thermal energy storage functions. When the mass ratio of CNTs to PAS was 2, the enthalpy reaches 160.3 J/g and the PEG loading reaches 95.56%. Moreover, the presence of CNTs increased the thermal conductivity of the thermal conductive layer to 0.433 W/m K. In addition, the bilayer CPCMs can conduct heat quickly and also have a good thermal insulation effect. The all‐in‐one material achieves a perfect combination of dual functions and provides a new solution for thermal management of power devices. Furthermore, the bilayer CPCMs also have great application potential in the field of infrared stealth.

Pt coating has been considered a promising strategy to protect the Ti porous transport layer substrate in a proton exchange membrane electrolyzer from corrosion. However, despite significant advancements in understanding the composition, process, and structure of Pt coatings, the underlying causes of coating failure remains unclear. Here, we systematically investigate the failure processes of magnetron-sputtered Pt coatings on Ti substrates through ex situ electrochemical tests that simulate anode operational conditions. Three different thicknesses of thin Pt coatings were prepared on Ti substrates by controlling the sputtering time. As the polarization time increases, the coating gradually fails and the failure time is directly related to the thickness of the coating. Experimental results indicate that Pt coatings approximately 6 nm thick begin to fail after 24 h of operation, with interfacial contact resistance reaching 220.61 mΩ cm2 after 48 h, which is significantly higher than that of bare Ti at 28.39 mΩ cm2. Further analysis reveals the role of oxygen in the coating failure: oxygen atoms generated from electrolyzed water first diffuse from the coating surface into the interface between the coating and the substrate, and eventually, the gradual buildup of oxygen pressure results in the detachment of the coating. A deeper understanding of the failure mechanism of coatings can enhance the efficiency and durability of water electrolysis for hydrogen production by guiding the design of more durable coatings.