Composite Substrate Research Articles

Mode Composite Ridged Substrate Integrated Coaxial Line for Multichannel Operation

Structural behavior of engineered cementitious composite substrate slab overlays for bridge deck and pavement applications

Abstract: Aim We evaluated how the combination of environmental characteristics affects the beta diversity of the EPT (Ephemeroptera, Plecoptera and Trichoptera) community across stream microhabitats. Methods The samples were collected in 12 streams around the Itaipu Reservoir (Paraná, Brazil). We sampled four types of substrates in triplicate with the aid of a Surber sampler. The samples were classified into CSD (sand and clay) and STO (gravel, pebbles, and boulders). The composite substrate of leaf packs (leaves and twigs) was divided into RLP (rapid leaf packs) and BLP (backwater leaf packs). Results We recorded a significant change in EPT composition among the microhabitats evaluated and different genera associated with each substrate category. However, beta diversity did not significantly differ among microhabitats. Thus, we found the highest beta diversity value in the CSD (sand and clay) category and the greatest contribution of the turnover component. Conclusions The partitioning of beta diversity into its components helped understand ecological patterns at local scales, highlighting the importance of microhabitat diversity in stream systems for maintaining the structure and composition of aquatic fauna.

This paper describes the wear and friction behavior of titanium nitride (TiN)-based coatings produced via chemical vapor deposition (CVD) in detail. Coatings composed of TiN, titanium carbide (TiC) and aluminum oxide (Al2O3) layers were applied to a tungsten carbide-cobalt composite and steel substrates. The elemental and phase compositions of these coatings, manufactured with varying deposition parameters and layer thicknesses, were determined using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The mechanical properties of the coatings were evaluated through Vickers microhardness testing, lubricant-free tribological model tests and scratch testing. For the linearly alternating tribological tests, a static counterpart made of yttria-stabilized zirconium oxide was utilized. The wear, friction and adhesive properties of the coatings were studied, revealing significant differences in tribological behavior based on their hardness, crystal structure and surface roughness. The tribological tests highlighted that coatings with sharp, spherical crystal structures on their surfaces exhibited the greatest resistance to abrasive and frictional stresses. The durability of the surface coatings was found to be primarily dependent on their adhesion and surface roughness.

ABSTRACTGastric cancer (GC) is a highly lethal malignancy, seriously threatening people's physical health. Accurate screening of gastric cancer could improve the survival rate of patients. Therefore, exploring noninvasive and efficient cancer screening methods for gastric cancer is of great significance. In the past few years, exosomes have received much attention for their potential in disease diagnosis and treatment. Here, the aim of this study was to explore the detection of serum exosomes via surface‐enhanced Raman spectroscopy (SERS) technique based on TiN‐Ag@Ag sol composite substrate, and its potential application in gastric cancer diagnosis is evaluated. Exosomes were extracted from the serum of 31 GC patients and 31 healthy controls (HC) using an exosome kit. This study used various machine learning algorithms such as principal component analysis linear discriminant analysis (PCA‐LDA), partial least squares discriminant analysis (PLS‐DA), support vector machine (SVM), and k‐nearest neighbor (KNN) algorithm to analyze SERS spectra, in order to distinguish between HC and GC. The results show that the k‐nearest neighbor algorithm performs the best in HC and GC classification. These results indicate that the combination of SERS and machine learning methods provides a new technological approach for gastric cancer screening. This study offers a new proposal for the universal applicability of analysis and identification with SERS of serum exosomes samples in clinical diagnosis.

Lung cancer with heterogeneity has a high mortality rate due to its late-stage detection and chemotherapy resistance. Liquid biopsy that discriminates tumor-related biomarkers in body fluids has emerged as an attractive technique for early-stage and accurate diagnosis. Exosomes, carrying membrane and cytosolic information from original tumor cells, impart themselves endogeneity and heterogeneity, which offer extensive and unique advantages in the field of liquid biopsy for cancer differential diagnosis. Herein, we demonstrate a Gramian angular summation field and MobileNet V2 (GASF-MobileNet)-assisted surface-enhanced Raman spectroscopy (SERS) technique for analyzing exosomes, aimed at precise diagnosis of lung cancer. Specifically, a composite substrate was synthesized for SERS detection of exosomes based on Ti3C2Tx Mxene and the array of gold-silver core-shell nanocubes (MGS), that combines sensitivity and signal stability. The employment of MXene facilitates the non-selective capture and enrichment of exosomes. To overcome the issue of potentially overlooking spatial features in spectral data analysis, 1-D spectra were first transformed into 2-D images through GASF. By using transformed images as the input data, a deep learning model based on the MobileNet V2 framework extracted spectral features from higher dimensions, which identified different non-small cell lung cancer (NSCLC) cell lines with an overall accuracy of 95.23%. Moreover, the area under the curve (AUC) for each category exceeded 0.95, demonstrating the great potential of integrating label-free SERS with deep learning for precise lung cancer differential diagnosis. This approach allows routine cancer management, and meanwhile, its non-specific analysis of SERS signatures is anticipated to be expanded to other cancers.

The catalytic activity coefficient and emissivity of the surface of thin-walled oxidation- and erosion-resistant coatings for high-speed aircraft were determined experimentally and theoretically. The coating was applied as an aerosol mixture to a carbon-carbon composite substrate, and the resulting sample was subjected to fully dissociated air to measure heat fluxes to the sample surface and its enthalpy. Using established relationships between total convective-diffusive heat fluxes, stagnation enthalpy, and the heterogeneous recombination coefficient of oxygen and nitrogen atoms into molecules, the catalytic activity coefficient and surface emissivity were calculated based on the Stefan–Boltzmann law utilizing the measured enthalpy (and temperature) of the wall. The experiments were performed on five coating types containing silicon, titanium, molybdenum, and boron. The findings were summarized in a table showing how the recombination coefficient and emissivity depend on heat fluxes and wall temperature.

This work used high velocity oxygen fuel spraying technology to prepare three types of ceramic-based self-lubricating sealing coating on C/SiC substrates, with Yttria-stabilized zirconia as the matrix and different mass fractions of Mo and Ag as lubricating phases. The compositions are S1(50%YSZ40%CaF210%Mo), S2(50%YSZ40%CaF210%Ag) and S3 (40%YSZ30%CaF210%Mo10%Ag10%SiO2). The friction coefficient and wear rate of the coating were examined at room temperature (RT), 400°C and 800°C. The effects of different lubricating phases on the tribological properties of the coating were compared. The wear mechanism of the coating under different temperature environments will be revealed by clarifying the evolution law of the microstructure of the coating. The results show that the addition of Ag can improve the lubricating ability of the coating. Ag element forms a continuous and smooth tribo-layer on the sliding surface to reduce the friction coefficient of the coating. In addition, the lubricating effect of Ag element is more significant at medium and low temperatures. At 800°C, the S3 coating with both Ag and Mo exhibited excellent tribological properties. The wear mechanism of the coating is that it starts with adhesive wear and gradually transitions to abrasive wear as friction continues. This work provides theoretical support and experimental evidence for the construction of ceramic-based self-lubricating sealing coating with a wide temperature range.

Super invar, with its near-zero coefficient of thermal expansion (CTE), has a great potential to be used in the design and fabrication of high-precision optical structures, such as optical mirror substrates. In order to reduce the weight and maintain the strength of the mirror substrate, several biomimetic lattice designs were investigated in this paper. The static modeling provides a systematic study on different types of biomimetic mirror substrates. The impact of structure parameters, such as the wall thickness, lattice unit length, height of the lattice structure, and the thickness of the side plate, are also studied. It turns out that the three-layer lattice-structured composite mirror substrate has the best performance. With AM techniques, three-layer gyroid optical structures, which are not possible to fabricate with conventional manufacturing technology, were designed and printed with our in-house-built AM machine. The stiffness test of the gyroid specimens was in good agreement with the modeling results. The gyroid structure shows about a 20% improvement over the honeycomb structure. The gyroid design reduces the equivalent density to 1.8 g/cm3 and has an order-of-magnitude improvement on the thermal deformation, while maintaining a comparable strength with that of beryllium.

Hypergravity-induced wetting profile of high-G droplets on composite substrates

ABSTRACT Current research efforts are directed towards utilizing polymers and biodegradable materials to develop innovative wireless devices for emerging applications within the sub-6 GHz spectrum. This study seeks to enhance the electrical and radiation characteristics of antennas while ensuring favorable environmental properties such as flexibility and Specific Absorption Rate (SAR). To this end, a comparative analysis of two flexible rectangular microstrip antennas constructed from novel polymer-based substrates is presented. One antenna uses a flexible composite substrate of polydimethylsiloxane (PDMS) embedded with carbon nanotubes (CNT), while the other employs a biodegradable polymer composite substrate made of polycaprolactone (PCL) reinforced with CNT. Results indicate that the PCL-CNT antenna surpasses the PDMS-CNT antenna in performance, in both flat and bent conditions. Specifically, at 2.4 GHz, the PCL-CNT antenna achieved a gain of 4.46 dBi and an efficiency of 0.70, compared to a gain of 3.94 dBi and an efficiency of 0.61 for the PDMS-CNT antenna. Furthermore, the superior performance of the PCL-CNT biodegradable polymer composite antenna suggests its potential for IoT applications and wireless communications, combining effective on-body usage with minimal environmental impact.

Abstract Surface‐enhanced Raman spectroscopy (SERS) technology boasts merits of fingerprint recognition, a low detection limit, high sensitivity, and straightforward operation, and holds a significant position in the realm of molecular detection (even at the single‐molecule level). Recently, molybdenum disulfide (MoS2), as a special SERS substrate, has demonstrated various advantages like high molecular compatibility and an anti‐fluorescence background, thus emerging as a promising non‐metal substrate. Nevertheless, so far, how to improve and achieve SERS effects comparable to metal substrates remains a challenge for MoS2 based substrates. Therefore, this work presents and acquires a 3D hollow structured MoS2, which can be achieved through a simple hydrothermal method. Fortunately, the substrate achieves a detection limit of 10−8 M and an enhancement factor of 106 for rhodamine 6G (R6G) molecules, significantly improving the performance of the non‐noble‐metal MoS2 SERS. Theoretical analysis suggests that this should be attributed to the enhanced charge transfer between the substrate and probe molecules brought by the distinct monolayer self‐assembly and oxygen substitution in the 3D MoS2 architecture. The work provides a novel method to enhance the SERS performance of 2D materials, which is readily achievable and is expected to become a key cornerstone for the development of composite substrates.

The purpose of this study was to evaluate the impact of various mechanical surface treatments on thesurface roughness and microtensile bond strength (µTBS) of aged composite resin cores bonded to CAD/CAM restorations. Composite resin specimens (Filtek Z350 XT, 3M-ESPE/Solventum) were thermally aged and subsequently divided into four groups (n = 36) according to surface treatments: UI-cleaning with ultrasonic diamond tip; AO-sandblasting with 50µm Al2O3; DB-cleaning with diamond burs; and CG-positive control group, without aging or surface treatment. Surface roughness was assessed using a profilometer and interferometer, with measurements taken on both sides of each specimen (n = 12). The surface characteristics were further analyzed through scanning electron microscopy (SEM) (n = 12). In addition, PMMA blocks were temporarily cemented (n = 12) onto the resin blocks, and after surface treatments, resin matrix glass-ceramic blocks were adhesively luted with dual-cure resin cement (RelyX Ultimate, 3&nbsp;M-ESPE/ Solventum, St. Paul, MN, USA) to the resin composite substrates. The CG specimens were adhesively luted to the indirect restorations without temporary restorations or surface treatment. After luting, the specimens were sectioned and tested for µTBS. The results (p = 0.05) from the profilometry and interferometry analyses indicated the highest surface roughness values for the DB group, followed by AO, UI, and CG. SEM analysis revealed marked morphological differences among the groups. Regarding µTBS, the GC specimens (25.78 ± 5.70MPa) and UI specimens (25.56 ± 11.36MPa) exhibited statisticallysimilar values, which were superior to those of the AO (12.25 ± 4.34MPa) and DB (13.16 ± 5.59MPa) groups (p < 0.001), which showed comparable results. In conclusion, the use of ultrasonic diamond tips resulted in the most favorable outcomes in terms of cleaning effectiveness, surface roughness, and bond strength among the surface treatments analyzed for resin composite cores.

Natural composite hydrogel regulated interface polymerization to prepare high performance nanofiltration membranes with wrinkled structure

Enhanced adhesion strength of copper deposited epoxy composite films for chip substrates by tuning copper oxide and internal stress

This study reports the tribological performance of a family of PMMA/SiO2 hybrid coatings with graphene oxide applied on composite laminate substrates. The transformation from graphite to graphene oxide was carried out using a high-energy mill for 90 minutes. The composite laminates of epoxy resin matrix and layers of bidirectional carbon fiber were obtained through the vacuum infusion process. The coatings were applied on the composite laminates using the dip-coating method. To disperse the graphene oxide in the hybrid solutions, an ultrasonic bath (40 kHz) was used during the immersion of the substrate. Tribological tests of erosive wear by solid particle impact (beach sand) were performed on a horizontal erosion test platform under conditions of pressure of 45 psi, impact velocity of 6 m/s, distance between nozzle and specimen of 10 mm and impact angle of 90°. The results showed that coatings with graphene oxide increase their protection against erosion by 50 (9-PMMA/1-SiO2-2GO) to 54% (9-PMMA/1-SiO2-1GO) more than the coating without graphene oxide. The results obtained could be considered for using this type of coating as an alternative protection on the leading edge of wind turbine blades that are exposed to conditions of erosion wear by solid particle impact.

Effects of Different Ratios of Coal Gangue and to Garden Soil Composite Substrates on the Growth and Physiology of Rhododendron Delavayi Franch. Seedlings

Near-infrared (NIR) light can be used in a variety of fields, including energy conversion devices and medicines. However, there are only a limited number of compounds with NIR absorption, and research into their effective use remains unexplored. Previous research in our laboratory has reported the enhancement of visible light absorption in devices based on the combination of metal nanoparticles and functional molecules. In this study, we applied the system of the previous study to investigate the fabrication conditions of composite substrates of indium cubic tin oxide nanoparticles (ITO NPs), which have localized surface plasmon resonance (LSPR) absorption in the NIR region, and silicon naphthalocyanine derivative (SiNPc), which absorbs NIR light, and the photocurrent of the fabricated substrates.ITO NPs were synthesised by a solvothermal method using ethylene glycol. SiNPc was synthesised by mixing SiNPcCl2 with 1-octanol. The conductive substrates were sonically cleaned, ozonated and then surface treated by the immersion in a 3-Aminopropyltrimethoxysilane (3-APTMS) solution. ITO NPs immobilized substrates were constructed by spin-coating method. This substrate was immersed in a SiNPc solution to construct the conductive substrate/3-APTMS/ITO NPs/SiNPc composite substrate.The synthesized nanoparticles were confirmed to be cubic ITO NPs with high crystallinity and approximately 30 nm per side from XRD and TEM images. The UV-Vis-NIR spectrum of the fabricated substrates showed the absorption of the soret band of SiNPc at 340 nm and the LSPR absorption of ITO NPs in the NIR region, indicating that the conductive substrate/3-APTMS/ITO NPs/SiNPc composite substrate was fabricated. Photocurrent measurements were carried out using NIR light, and the cathode current was observed.

Gallium Oxide is an emerging ultra-wide band gap semiconductor with promising material properties relevant for high performance power electronic devices. The availability of large area bulk substrates using melt growth techniquesand the wide range of tunable n-type conductivity makes it a compelling semiconductor material platform for next-generation power devices. Lateral Devices: Homoepitaxial Si-doped channel layers are grown using metal-organic vapor phase epitaxy (MOVPE) on NCT and Synoptics (010) Ga2O3 bulk substrates after chemical cleaning to minimize impurities at the substrate-epitaxial layer interface, necessary for pinching off the lateral field effect transistors. Excellent electron mobilities, contact resistance values, breakdown voltages and power figures of merit are demonstrated in β-Ga2O3 epitaxial films and devices. MOVPE-grown β-Ga2O3 thin films with electron mobility values close to the predicted theoretical maximum (~ 200 cm2/Vs) are achieved at low (600°C) and high (800°C) growth temperatures. A low-temperature MOVPE masked ohmic contact regrowth technique is developed with a low contact resistance value. Multi-kilovolt (up to 4.5 kV) class β-Ga2O3 transistors are demonstrated with state-of-the-art power figures of merit exceeding several times the theoretical maximum of Silicon. A channel-buffer stack engineering is demonstrated that enabled record-high electron mobility values in doped β-Ga2O3 films. High-current (> 100 mA/mm) and VBR (up to ~ 3kV) β-Ga2O3 MOSFETs are realized on an engineered β-Ga2O3 /SiC composite substrate – for enhanced bottom-side device cooling. Tri-Gate β-Ga2O3 MESFETs with record high power figure of merit (~1 GW/cm2) are demonstrated. We report on the demonstration of kV-class β-Ga2O3 MOSFETs fabricated on 1-in. bulk substrates using metalorganic vapor phase epitaxy (MOVPE) with disilane (Si2H6) as the silicon precursor. In this talk, we will highlight some of these critical advances in β-Ga2O3 epitaxy/devices, pushing the boundary of β-Ga2O3device performance. Vertical Devices: Gallium Oxide devices are very attractive for next-generation grid-scale power rectifiers and transistors. We report a vertical β-Ga2O3 Schottky barrier diode (SBD) with BaTiO3 as field plate oxide on a low doped thick epitaxial layer exhibiting 2.1 kV breakdown voltage. A thick drift layer of 11 μm with a low effective doping concentration of 8 × 1015 cm–3 is used to achieve high breakdown voltage. Using the high-k dielectric with a dielectric constant of 248, the breakdown voltage increases from 816 V for the non-field-plated SBD to 2.1 kV (>2× improvement) for the field-plated SBD without compromising the on-state performance.We introduce vertical Schottky barrier diodes (SBDs) based on β-Ga2O3 with trench architecture, featuring a high-permittivity dielectric RESURF structure. These diodes are designed for application demanding high voltage and current capacities while maintaining ultra-low reverse leakage currents. The trench design plays a pivotal role in reducing the electric field at the metal–semiconductor junction, thereby yielding minimal reverse leakage attributed to field emission under high reverse bias conditions. Additionally, the incorporation of a high-k dielectric helps to suppress leakage through the trench bottom corner dielectric layer. The incorporation of a trench geometry, coupled with the high-permittivity dielectric RESURF, effectively reduces the surface electric field at the metal-semiconductor junction. This reduction facilitates the use of a lower work-function anode contact, further diminishing the turn-on voltage. The use of high-k dielectric also significantly reduces the dielectric leakage contribution to the overall reverse leakage of the diode. Large-area SBDs with areas of 1mm2 and 4mm2 exhibit pulsed forward current of 6A/20A and a catastrophic breakdown voltage of 1.74kV/1.4kV, surpassing other β-Ga2O3-based large-area power diodes, while small-area SBDs (200×200 µm2) do not exhibit catastrophic breakdown until 3kV. The large-area SBDs also demonstrate lower capacitance, stored charge, and stored energy compared to commercial SiC SBDs, indicating potential for superior switching performance. The combination of lower stored charge and a low forward voltage drop results in an excellent trade-off between conduction and switching power loss, yielding a QCVF figure of merit comparable to commercial bare die SiC SBDs.We report on the fabrication and characterization of a NiOx/β-Ga2O3 heterojunction diode (HJD) that uses a metallic Nickel (Ni) target to deposit NiOx layers via reactive RF magnetron sputtering and lift-off processing with >3 kV breakdown voltage, record-low reverse current leakage under high reverse bias, and high junction electric fields (4 MV/cm). The breakdown voltage was measured to be greater than 3 kV with a noise floor-level reverse leakage current density (~10-6 A/cm2) until 3 kV. Such rapid advances in Gallium Oxide device engineering will unleash the potential for these devices for next-generation grid-scale power electronics. We acknowledge funding from the Coherent/II–VI Foundation and AFOSR.

Synthesis of UiO-66/Ag/TiO2 composite as reusable SERS substrate