Composite Substrate Research Articles (Page 2)

This paper examines the wettability and interactions between ceramic and composite materials soldered with Bi-based solder containing 11 wt.% of silver and 3 wt.% titanium using indirect electron beam soldering technology. The Bi11Ag3Ti solder, with a melting point of 402 °C, consisted of a bismuth matrix containing silver lamellae. Titanium, acting as an active element, positively influenced the interaction between the solder and the joined materials. SiC and Ni-SiC substrates were soldered at temperatures of 750 °C, 850 °C, and 950 °C. Measurements of wettability angles indicated that the lowest value (20°) was achieved with SiC substrates at 950 °C. A temperature of 750 °C appeared to be the least suitable for both substrates and was entirely unsuitable for Ni-SiC. It was also observed that the Bi11Ag3Ti solder wetted the SiC substrates more effectively than Ni-SiC substrates. The optimal working temperature for this solder was determined to be 950 °C. The shear strength of the joints soldered with the Bi11Ag3Ti alloy was 23.5 MPa for the Al2O3/Ni-SiC joint and 9 MPa for the SiC/Ni-SiC joint.

Fabrication of UL-AuAgMSs@β-CD composite substrate for synergistically enhanced SERS trace detection of organophosphorus pesticide residues

Anovel composite SERS substrate was developed based on gold nanoparticles (AuNPs) and poly(N-isopropylacrylamide) (PNIPAM) hydrogel. PNIPAM hydrogel is a temperature-responsive material with a lower critical solution temperature (LCST) of about 32°C, regulating its swelling-shrinking behavior by changing temperature to evaluate the enrichment efficiency of target molecules. Experimental results demonstrated that the substrate exhibited a swelling ratio of 400-600% at room temperature, facilitating the efficient enrichment of paraquat molecules. The optimal Raman response was observed when the substrate contained a NIPAM concentration of 0.8mol/L and an AuNPs concentration of 300%. Additionally, the substrate exhibited excellent detection performance, including high sensitivity, good reproducibility, uniformity, and temporal stability. The minimum detectable concentration of paraquat in standard solutions was 0.1μg/L. In apple juice and orange juice, the detection limit ranged from 0.072 to 0.112μg/L, with spiked recoveries of 85.55%-110.55% and 88.57%-107.15%, respectively. This study presents a highly selective and reliable SERS sensing strategy for the rapid detection of trace paraquat in juice samples.

A new, simple machine was developed to address a long-standing challenge in biomedical and mechanical engineering: how to enhance the primary stability and long-term integration of screws and implants in low-density or heterogeneous materials, such as bone or composite substrates. Traditional screws often rely solely on external threading for fixation, leading to limited cohesion, poor integration, or early loosening under cyclic loading. In response to this problem, we designed and built a novel device that leverages a unique mechanical principle to simultaneously perforate, collect, and compact the substrate material during insertion. This mechanism results in an internal material interlock, enhancing cohesion and stability. Drawing upon principles from physics, chemistry, engineering, and biology, we evaluated its biomechanical behavior in synthetic bone analogs. The maximum insertion (MIT) and removal torques (MRT) were measured on synthetic osteoporotic bones using a digital torquemeter, and the values were compared directly. Experimental results demonstrated that removal torque (mean of 21.2 Ncm) consistently exceeded insertion torque (mean of 20.2 Ncm), indicating effective material interlocking and cohesive stabilization. This paper reviews the relevant literature, presents new data, and discusses potential applications in civil infrastructure, aerospace, and energy systems where substrate cohesion is critical. The findings suggest that this new simple machine offers a transformative approach to improving fixation and integration across multiple domains.

It is difficult to simultaneously achieve surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF) for noble metals. Herein, a composite substrate is demonstrated based on the rational construction of Ag nanoparticles (Ag NPs) and inverse opal polydimethylsiloxane (PDMS) for surface Raman fluorescence dual enhancement. The well-designed Ag nanoparticle (Ag NP)-decorated inverse opal PDMS (AIOP) composite substrate is fabricated using the polystyrene (PS) photonic crystal method and the sensitization reduction technique. The inverse opal PDMS enhances the electromagnetic (EM) field by increasing the loading of Ag NPs and plasmonic coupling of Ag NPs, leading to SERS activity. The thin shell layer of polyvinyl pyrrolidone (PVP) in core–shell Ag NPs isolates the detected molecule from the Ag core to prevent the fluorescence resonance energy transfer and charge transfer to eliminate fluorescence quenching and enable SEF performance. Based on the blockage of the core–shell structure and the enhanced EM field originating from the inverse opal structure, the as-fabricated AIOP composite substrate shows dual enhancement in surface Raman fluorescence. The AIOP composite substrate in this work, which combines improved SERS activity and SEF performance, not only promotes the development of surface-enhanced spectroscopy but also shows promise for applications in flexible sensors.

3D composite SERS substrate constructed by Au-Ag core-satellite NPs and polystyrene sphere for ultrasensitive ratiometric Raman detection of cotinine.

Flexible thermoelectric generator with integrated Cu foam heat sink and embedded composite substrate for enhanced body heat harvesting

Impact of gradient nanocomposite coating design on the surface mechanical properties of soft composite substrate

Bi-YIG ferrite with high dielectric constant and narrow FMR linewidth and NiCuZn ferrite composite substrates for ultrawideband circulators

The reproduction of turangа-poplar is better carried out by the method of micropropagation, which allows you to obtain high-quality material that is advisable to use in reforestation and landscaping of cities, especially with arid climates. Adaptation of in vitro plants was carried out in greenhouse conditions in containers with a volume of 450 ml. Different in terms of composition substrates were used. The substrate of option 3 turned out to be the most effective: peat and perlite in layers, peat in the lower part, perlite in the upper part; and option 4 - a mixture of peat and black soil in a ratio of 6/4 with a recess filled with perlite. The experiments were carried out in natural daylight in a frame heated greenhouse with a film coating at a temperature of +20...+27 °C. Plants were used in three stages of root system development. After transplantation, they were watered with an antifungal drug solution and water. To prevent evaporation of moisture from in vitro plants and from the surface of the substrate, a transparent cap with a screw-off lid was covered from above. Containers with turangа plants fully adapted to non-sterile conditions were transferred to open areas outside the greenhouse for hardening.

The Internet of Things (IoT) is one of the pivotal technologies driving the digital transformation of industry, business, and personal life. Along with new opportunities, the exponential growth of IoT devices also brings environmental challenges, driven by the increasing accumulation of e-waste. This paper introduces a novel, compact, cubic-shaped rectenna with a 3D-printed composite substrate featuring five identical patches. The design aims to integrate RF energy harvesting technology with eco-friendly materials, enabling its application in powering next-generation sustainable IoT systems. Due to its symmetrical design, each patch antenna achieves a bandwidth of 130 MHz within the frequency range of 2.4 GHz to 2.57 GHz, with a maximum efficiency of 60.5% and an excellent isolation of below −25 dB between adjacent patch antennas. Furthermore, measurements of the rectifier circuit indicate a maximum conversion efficiency of 33%, which is comparable to that of other rectennas made on 3D-printed substrates. The proposed visually unobtrusive design not only enhances compactness but also allows the proposed rectenna to harvest RF energy from nearly all directions.

Heat dissipation in nanomagnetic devices mediated by femtosecond laser excitation constitutes one of the pressing challenges toward energy‐efficient applications yet to be solved. Of particular interest are heterostructures based on 2D van der Waals (vdW) magnets, which benefit from superior interfacial controllability, mechanical flexibility for smart storage platforms, and open‐source for large‐scale production. However, how heat affects the ultrafast magnetization dynamics in such systems, and/or how the spin dynamics can provide alternative pathways for effective heat dissipation have so far been elusive. Here it is shown that the missing link between magnetization dynamics and heat transport is mediated by the thermal conductivity mismatch between the underneath substrate and the vdW magnet. By modeling the laser‐induced ultrafast spin dynamics of three popular vdW materials (CrI3, CrGeTe3, Fe3GeTe2) of different electronic characteristics across sixteen substrates of distinct chemical composition, it is found that both the demagnetization and remagnetization timescales are very sensitive to the phonon temperature dynamics through the supporting materials, which defines the heating dissipation efficiency at the interface. The process can be further tuned with the thickness of the vdW magnets, where thin (thick) systems result in faster (slower) magnetization dynamics. It is unveiled that the non‐thermal nature of spin dynamics in vdW heterostructures creates interfacial spin accumulation that generates spin‐polarized currents with dominant frequencies ranging from 0.18 to 1.0 GHz accordingly to the layer thickness and substrate. The findings demonstrate that substrate engineering liaised with the choice of magnetic compounds open venues for efficient spin‐heat control, which ultimately determines the optically excited magnetic characteristics of the vdW layers.

Regulating uniformity and stability of substrates remains a key challenge in developments of flexible surface enhanced Raman spectroscopy (SERS) sensors. Herein, we fabricated a flexible SERS platform by integrating ultra-stable nitrogen-doped graphite-coated gold nanoparticles (Au@NG) with a polydimethylsiloxane (PDMS) film via optimized microarray spray-coating techniques, forming a composite substrate denoted as Au@NG@PDMS. The structure and chemical stability of the Au@NG nanoparticles were confirmed by TEM and Raman spectroscopy. The presence of a thin, nitrogen-doped graphite shell effectively protected the Au core against acidic, alkaline, and oxidative environments. Benefiting from the superior mechanical flexibility of PDMS, the Au@NG@PDMS substrate maintained excellent SERS signal reproducibility under repeated bending and stretching cycles. Furthermore, we demonstrated that adjusting the solvent evaporation rate by selecting solvents in spraying process significantly improved the uniformity, reproducibility, and overall SERS performance of the substrate. Using this platform, we achieved highly sensitive and quantitative detection of crystal violet across a concentration range from 10nM to 10 µM and successfully identified trace levels (20ng/mL) of thiram residues directly on the surface of apples. The resulting flexible SERS substrate exhibits outstanding structural stability, signal uniformity, and surface conformability making it highly promising for practical applications in on-site pesticide residue detection in agricultural monitoring.

Innovative Thermal Spray Deposition Techniques for Polymer and Polymeric Matrix Composite Substrates: Methodologies, Characteristics, and Real-World Applications

Asurface-enhanced Raman scattering (SERS) composite substrate based on the synergy between Au@ZIF-8 nanoparticles (NPs) and multilayer Au/Al2O3 thin films (MLFs) was designed to achieve electromagnetic field enhancement by coupling localized surface plasmon resonance (LSPR) with bulk plasmon polariton (BPP). Surface plasmon polaritons (SPPs) in MLFs can couple to form BPP, which significantly enhance the localized electric field intensity within the Au@ZIF-8 (zeolitic imidazolate framework-8) nanogaps. Moreover, the electric field amplification increases progressively with the number of film layers. Within the Au@ZIF-8 core-shell structure, the ZIF-8 serves as a shell to control particle spacing (thereby preventing agglomeration) and concentrate probe molecules within electromagnetic field hotspots. The experimental results demonstrate detection limits of 8.6 × 10-12M for rhodamine 6G (R6G) and 1.5 × 10-9M for Crystal Violet (CV), representing a significant improvement compared with conventional SERS substrates. This study provides new insights into the synergistic mechanisms of SPP with LSPR, and demonstrates the potential applications of composite Raman substrates in ultrasensitive molecular detection.

Lanthanide metal-organic frameworks (Ln-MOFs) have temperature-responsive luminescent properties for sensing applications. In this study, we developed a dual-emission fluorescent label (SCF-TGIC@MOF) with temperature-responsive properties, achieved by doping epoxy-modified Eu-MOF (TGIC@Eu-MOF) into a sodium alginate/carboxymethylcellulose composite substrate containing fluorescein (SCF). The composites modified with triglycidyl isocyanurate (TGIC) showed improved fluorescence intensity, thermal stability, and relative sensitivity compared withunmodified Eu-MOF. The composite of the substrate improved the physicochemical stability of the label, while the label showed a visible green to red fluorescence transition corresponding to temperature changes in the physiological range (277.15-313.15K). The responsiveness of the label to temperature suggests that it has the potential to be used as a luminescent thermometer. In addition, the monitored temperature range suggests that the smart label has value for applications in environmental temperature monitoring. And this may apply to the preservation and storage of food products, such as vegetables and aquatic products.

Recent developments in wearable wireless communication systems have significantly increased the demand for stretchable antennas. The substrate, which is a critical component for antennas, has a great impact on the antenna's electromagnetic performance and mechanical properties, particularly at millimeter-wave frequencies. However, conventional methods of incorporating low-loss ceramics into stretchable polymers cannot achieve an equilibrium between low dielectric loss and optimal stretchability. To resolve this issue, we present a novel approach that synergistically integrates electrospun barium titanate (BaTiO3) nanofibers with poly(dimethylsiloxane) (PDMS), achieving a composite membrane substrate with ultralow dielectric loss and exceptional stretchability. Based on this advanced substrate, we develop a wearable array antenna that demonstrates stretchability and remarkable radiation characteristics, effectively addressing the constraints associated with conventional PDMS-based antennas. This proposed antenna is expected to be an excellent candidate for next-generation wearable and stretchable millimeter-wave 5G wireless communication.

This study aims to compare the adhesion properties of single lap joints fabricated from carbon fiber-reinforced vinyl ester composites, focusing on the effects of different adhesives and inserts. The research involved evaluating six adhesives: an aerospace-grade epoxy, two acrylic adhesives, two epoxy resins, and a vinyl ester resin. The substrates, produced via vacuum-assisted resin infusion with unidirectional carbon fiber and vinyl ester resin, were bonded using these adhesives. The impact of three inserts—3D-printed polylactic acid (PLA) nets with 0.2 mm and 0.4 mm hole spacings, and an e-glass chopped strand mat (CSM)—on the tensile properties of the SLJ was examined. Finite Element Analysis (FEA) predicted stress distributions in the joints. The results identified vinyl ester adhesive as the most suitable due to its superior lap shear strength and stiffness. Although all inserts reduced lap shear strength and modulus compared to specimens without inserts, the CSM insert showed the best performance among the inserts. The study highlights the importance of matching adhesive material to the resin used in the composite substrate, enhancing mechanical strength through better cross-linking reactions. The findings offer valuable insights for improving the design and performance of adhesively bonded joints in carbon fiber-reinforced vinyl ester composites, especially in applications requiring high strength and durability.

Abstract This study examines the propagation of Love‐type waves in a functionally graded conductive polymer (FGCP) layer bonded to a functionally graded piezoelectric fiber‐reinforced composite (FGPFRC) substrate under the influence of an impulsive line source. The elastic properties of the FGCP layer vary exponentially with depth, while those of the substrate follow a sine hyperbolic variation with the heterogeneity parameter and magnifying constant. The proposed structure is considered under the influence of the impulsive force due to a line source at its interfacial surface. The coupled electro‐mechanical equations are solved using Fourier transforms and Green's function techniques to analyze the mechanical and electrical displacements. The dispersion relation of the Love‐type wave for this proposed model is derived using continuity conditions and the symmetric properties of the Green's function. Furthermore, the obtained dispersion relation is deduced into the standard form of the Love‐type wave dispersion under particular cases. The effects of graded parameters, scaling parameters, viscosity, conductivity, and fiber‐reinforced parameters of layer‐substrate materials on the phase velocity curves of the Love‐type wave are demonstrated graphically. The insights gained contribute to understanding wave propagation in complex composite systems and provide a basis for designing and optimizing Love‐type wave‐based devices for applications in sensing, signal processing, and beyond.

Embedding auxetic structures in composite substrate layer for enhancing performance of stretchable strain sensors