Search Results (8,986)

Continuous nettle fiber-reinforced PLA composites were fabricated using a custom-designed fused deposition modeling (FDM) 3D printer equipped with an in-nozzle fiber impregnation system. The influence of hatch spacing and layer thickness on fiber volume fraction, tensile strength, and fracture surface morphology was systematically examined. Fiber content increased from 7.94 vol.% to 12.21 vol.% when hatch spacing was reduced from 1.0 mm to 0.6 mm at a constant 0.4 mm layer thickness, and from 12.21 vol.% to 24.43 vol.% when layer thickness was decreased from 0.4 mm to 0.2 mm at a fixed 0.6 mm hatch spacing. When compared to neat PLA, tensile strength was improved by 18.69% for the configuration of 1_04 and 75.83% for the configuration of 06_02. SEM analysis revealed orderly fiber deposition in all samples, with 3D-printing-induced voids and fiber pull-out observed on fracture surfaces. Reduced hatch spacing and layer thickness resulted in denser fiber packing, consistent with mechanical performance trends. The results highlight the strong influence of printing parameters on the microstructural and mechanical behavior of continuous natural fiber composites produced by FDM. Full article

With the rapid advancement of electronic devices, Internet of Things (IoT) technology has become increasingly integrated into everyday life. However, its broader development has been restricted by challenges related to long-term maintenance and the frequent need for power source replacements. Among the available power supply solutions, thermoelectric power generation has garnered significant interest due to its high reliability. Nevertheless, the widespread application of thermoelectric generators (TEGs) in IoT remains limited due to their relatively low conversion efficiency and structural fragility. This review systematically summarizes recent strategies aimed at enhancing the output performance and durability of TEGs through improvements in manufacturing processes and performance optimization techniques. It highlights several fabrication methods capable of endowing devices with superior flexibility and reliability, including screen printing, chemical vapor deposition (CVD), and electrospray deposition. Additionally, we discuss two key approaches for improving power generation performance: advanced material selection and multi-mechanism hybridization. Finally, the article explores the applications of TEGs in thermal energy harvesting from wearable devices, ambient environments, and aerospace fields, demonstrating their substantial potential to provide sustainable energy for IoT devices. Full article

At present, most studies in the field of Wire-Friction Stir Additive Manufacturing (W-FSAM) adopt the side wire feeding method. However, the side wire feeding method has problems in that the wire feeding tube occupies working space and the tool is prone to clogging. To address this, this study proposes a Coaxial Wire Feeding-Friction Stir Additive Manufacturing (CWF-FSAM) method. The CWF-FSAM device adopts a structure where a fixed shaft is coaxially nested inside the stirring shaft, and the fixed shaft is machined with through-channels along the circumferential direction for wire feeding, which eliminates the limitation of the wire feeding tube. This study elaborates on the structure of the CWF-FSAM device, then uses 6061 aluminum alloy as the deposition material for additive manufacturing, and conducts characterization and analysis on the microstructure and mechanical properties of the deposited components. The results show that the interlayer bonding of the deposited components is dense without defects. The components exhibit uniform and fine equiaxed grains, with the average grain sizes of the top, middle, and bottom parts being 3.52 µm, 3.35 µm, and 4.07 µm, respectively. In terms of mechanical properties, the tensile strengths of the components along the building direction (BD) and longitudinal direction (LD) both reach 70% of that of the base material (BM) wire. The hardness ranges from 36 HV to 42 HV. In addition, closed-loop components were prepared by continuous counterclockwise deposition using the CWF-FSAM device. The tensile strengths of the overlapping area, straight section, and corner were 124.45 MPa, 125.88 MPa, and 126.95 MPa, respectively. The overall performance of the closed-loop components is uniform and stable, which indicates that the CWF-FSAM-deposited components have good mechanical property isotropy. Full article

Transition-metal oxides (TMOs) possess pronounced optoelectronic properties and are widely exploited in photovoltaics and photocatalysis. Here, we introduce a hot wire oxidation sublimation deposition (HWOSD) that directly converts elemental Mo and W into amorphous MoO_x and WO_x films on various substrates. Scanning electron microscopy and atomic force microscopy reveal uniform thickness and conformal coverage over textured and planar surfaces. X-ray photoelectron spectroscopy indicates high oxygen contents with stoichiometric ratios of 2.94 (MoO_x) and 2.91 (WO_x). Optical measurements show transmittances > 94% across 400–1200 nm, yielding optical band gaps of 1.86 eV (MoO_x) and 2.67 eV (WO_x). The conductivities of MoO_x and WO_x were 2.58 × 10⁻⁶ S cm⁻¹ and 5.14 × 10⁻⁷ S cm⁻¹ at room temperature, and the TMO/Si surface potential differences are 200 mV and 114 mV, respectively. Minority-carrier-lifetime measurements indicate that MoO_x films confer an additional passivation benefit to the i a-Si:H/c-Si/i a-Si:H stack. Annealing of MoO_x and WO_x realized their phase transition from an amorphous state to a polycrystalline state, with changes in their optical transmittance in the visible light region. Investigation of the photovoltaic performances of MoO_x and WO_x as HTLs deposited by HWOSD demonstrates their excellent electronic functionality in optoelectronics. These results establish HWOSD as a scalable, low-temperature method to fabricate high-quality TMO films and expand their potential in advanced optoelectronic devices. Full article

Suspended microchannel resonators (SMRs) are powerful tools for mass, density, and viscosity sensing. Among various transduction methods, full piezoelectric transduction offers key advantages, including on-chip integration, low energy dissipation, and linear response. This work explores sub-200 nm Al_0.6Sc_0.4N thin films for SMR transduction, benchmarking them against their well-established AlN predecessor. By integrating the piezoelectric stack into low-stress silicon nitride (ls-SiN_x) beam resonators, we investigate the impact of bottom electrode design, photoresist removal prior to deposition, and deposition bias on film quality. Characterization includes X-ray diffraction (XRD), scanning electron microscopy (SEM), d₃₁ piezoelectric coefficient, relative dielectric permittivity, and breakdown field measurements. Results illustrate the impacts of the studied parameters and demonstrate a fourfold increase in d₃₁, compared to AlN, confirming the strong potential of Al_0.6Sc_0.4N for high-performance SMR transduction. Full article

Rapid on-site detection of chemical warfare agents (CWAs) is vital for security and environmental monitoring. In this work, copper(I) oxide (Cu₂O) nanowire (NW) chemiresistors were investigated as gas sensors for low-concentration organophosphorus chemical warfare agent (CWA) simulants. The NWs were hydrothermally synthesized and deposited onto microheater platforms, enabling them to operate at elevated working temperatures. Their sensing performance was tested against a range of vapor-phase simulants, including dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), diethyl ethylphosphonate (DEEP), diphenyl phosphoryl chloride (DPPCl), parathion, diethyl phosphite (DEP), diethyl adipate (DEA), and cyanogen chloride (ClCN). Fully oxidized P(V) simulants (DMMP, DEEP, TEP) produced modest, predominantly reversible responses (~3–6% RR). On the contrary, DPPCl and DEP induced the strongest relative responses (RR −94.67% and >200%, respectively), accompanied by irreversible surface modification as revealed by SEM and EDS. ClCN produced a substantial but reversible negative response (RR −9.5%), consistent with transient oxidative interactions. Surface poisoning was confirmed after exposure to DEP and DPPCl, which left phosphorus or chlorine residues on the Cu₂O surface. These results highlight both the promise and limitations of Cu₂O NW chemiresistors for selective CWA detection. Full article

This study investigates the microstructure evolution and mechanical properties of DSS2209 duplex stainless steel fabricated via cold metal transfer wire arc additive manufacturing (CMT-WAAM). The as-deposited thin-wall components exhibit significant microstructural heterogeneity along the build height due to thermal history variations. Optical microscopy, SEM-EDS, and EBSD analyses reveal distinct phase distributions: the bottom region features elongated blocky austenite with Widmanstätten austenite (WA) due to rapid substrate-induced cooling; the middle region shows equiaxed blocky austenite with reduced grain boundary austenite (GBA) and WA, attributed to interlayer thermal cycling promoting recrystallization and grain refinement (average austenite grain size: 4.16 μm); and the top region displays coarse blocky austenite from slower cooling. Secondary austenite (γ₂) forms in interlayer remelted zones with Cr depletion, impacting pitting resistance. Mechanical testing demonstrates anisotropy; horizontal specimens exhibit higher strength (UTS: 610 MPa, YS: 408 MPa) due to layer-uniform microstructures, while vertical specimens show greater ductility (elongation) facilitated by columnar grains aligned with the build direction. Hardness ranges uniformly between 225–239 HV. The study correlates process-induced thermal gradients (e.g., cooling rates, interlayer cycling) with microstructural features (recrystallization fraction, grain size, phase morphology) and performance, providing insights for optimizing WAAM of large-scale duplex stainless steel components like marine propellers. Full article

Tunnel drainage pipes are prone to blockage due to mineral crystallization and deposition from water, which seriously affects the long-term stable operation of the drainage system and compromises the safety of tunnel structures. To address this issue, it is imperative to develop efficient anti-crystallization technologies to extend the service life of drainage systems. In this study, a series of anti-crystallization performance experiments on tunnel drainage pipes were designed and conducted based on magnetic treatment technology. The inhibitory effects of magnetic fields on crystal formation and deposition were systematically investigated under various conditions, including different magnetic field intensities, magnetic field coverage angles, magnetic field orientations, and water flow velocities. The results indicate that under magnetic influence, the crystal morphology inside the pipes changed from regular cubic structures to irregular forms with rough surfaces and loose structures, showing a transformation trend from calcite to aragonite and vaterite. Compared with conventional PVC pipes, the anti-crystallization effect was most pronounced under the following conditions: magnetic field intensity of 40 Gs, coverage angle of 90°, vertical magnetic field orientation, and higher water flow velocity. The findings of this study provide a novel approach to mitigating crystallization-induced blockages in tunnel drainage systems and contribute to reducing tunnel-related pathologies such as lining cracks, water seepage, and structural deterioration caused by poor drainage. Full article

Chemical vapor deposition (CVD) is a high-precision thin-film fabrication technique that is widely applied in semiconductor manufacturing, optical component manufacturing, and materials science. The performance of the deposition process plays a critical role in determining the quality of the final product. However, multiple variables in CVD processes have a highly nonlinear nature that involves complex interactions. Therefore, conventional experimental methods exhibit limitations in quality control and process optimization for CVD. In this study, we developed a predictive model based on process parameters and quality indicators using machine learning techniques to analyze and optimize the CVD processes. Through data collection, feature selection, model training, and model validation, the developed machine-learning algorithms were tested and evaluated. The adopted machine learning algorithms effectively captured the nonlinear relationships between multiple variables in CVD processes, accurately predicted thin-film quality indicators, and provided data for optimizing process parameters. In addition, the analysis results of feature importance revealed the effect of each key parameter on product quality, offering a basis for process improvement. Overall, the results of this study highlight the capability of machine learning algorithms for quality control and optimization in CVD processes for future advancements in smart manufacturing. Full article

Developing perovskite solar cells (PSCs) with both high performance and long-term stability remains a critical challenge and research focus in the field of photovoltaic devices. Herein, we report a multi-step spin-coating strategy for high-efficiency 2D/3D perovskite heterojunction solar cells by sequentially depositing low-concentration 3-pyridine methylamine iodine solutions onto 3D perovskite films. This approach enables controlled Ostwald ripening and forms graded 2D/3D heterointerfaces rather than insulating capping layers, yielding a champion device with a PCE of 22.7%, significantly outperforming conventional 2D/3D planar counterparts. The optimized structure exhibits enhanced carrier extraction, suppressed recombination, and exceptional humidity stability; the hydrophobic structure further enabled >85% initial efficiency retention after 800 h at 45% relative humidity (RH) for target devices. This study establishes a novel research paradigm for developing high-performance and stable 2D/3D perovskite solar cells through gradient dimensionality engineering. Full article

Asymmetric nanomotors are a class of self-propelled nanoparticles that exhibit asymmetries in shape, composition, or surface properties. Their unique asymmetry, combined with nanoscale dimensions, endows them with significant potential in environmental and biomedical fields. For instance, glutathione (GSH) induced chemotactic nanomotors can respond to the overexpressed glutathione gradient in the tumor microenvironment to achieve autonomous chemotactic movement, thereby enhancing deep tumor penetration and drug delivery for efficient induction of ferroptosis in cancer cells. Moreover, self-assembled spearhead-like silica nanomotors reduce fluidic resistance owing to their streamlined architecture, enabling ultra-efficient catalytic degradation of lipid substrates via high loading of lipase. This review focuses on three core areas of asymmetric nanomotors: scalable fabrication (covering synthetic methods such as template-assisted synthesis, physical vapor deposition, and Pickering emulsion self-assembly), propulsion mechanisms (chemical/photo/biocatalytic, ultrasound propelled, and multimodal driving), and functional applications (environmental remediation, targeted biomedicine, and microelectronic repair). Representative nanomotors were reviewed through the framework of structure–activity relationship. By systematically analyzing the intrinsic correlations between structural asymmetry, energy conversion efficiency, and ultimate functional efficacy, this framework provides critical guidance for understanding and designing high-performance asymmetric nanomotors. Despite notable progress, the prevailing challenges primarily reside in the biocompatibility limitations of metallic catalysts, insufficient navigation stability within dynamic physiological environments, and the inherent trade-off between propulsion efficiency and biocompatibility. Future efforts will address these issues through interdisciplinary synthesis strategies. Full article

Aluminum nitride (AlN) is a material of wide interest in the optoelectronics and high-power electronics industry. The deposition of AlN thin films at elevated temperatures is a well-established process, but its implementation on flexible substrates with conductive oxides, such as ITO-glass or ITO-PET, poses challenges due to the thermal degradation of these materials. In this work, the deposition and characterization of AlN thin films by reactive sputtering at a low temperature (RT and 100 °C) on ITO-glass and ITO-PET substrates are presented. The structural, optical, and electrical properties of the samples have been analysed as a function of the sputtering power and the deposition temperature. XRD analysis revealed the absence of peaks of crystalline AlN, indicative of the formation of an amorphous phase. EDX measurements performed on the ITO-glass substrate with a radiofrequency power applied to the Al target of 175 W confirmed the presence of Al and N, corroborating the deposition of AlN. SEM analyses showed the formation of homogeneous and compact layers, and transmission optical measurements revealed a bandgap of around 5.82 eV, depending on the deposition conditions. Electrical resistivity measurements indicated an insulating character. Overall, these findings confirm the potential of amorphous AlN for applications in flexible optoelectronic devices. Full article

The current research aims to develop a simple, sensitive, and green analytical method for the group extraction/monitoring of 19 organochlorine and organophosphorus pesticides from fruit juices using microwave radiation to assist a cloud point extraction (MW-CPE) in combination with re-extraction in hexane and GC-MS/MS detection. The main experimental factors affecting the CPE and re-extraction have been optimized. The matrix-matched calibration was performed, and the limit of quantification (LOQ) for all studied pesticides at optimized conditions ranged between 5 and 47 ng L⁻¹. When applying only 0.25 mL of hexane for re-extraction, the proposed method shows good accuracy and precision. The “greenness” of the developed MW-CPE-GC-MS/MS method was assessed using the AGREE prep software. The method has been successfully implemented in pesticide analysis in commercially available fruit juices (lemon concentrate and red apple juice). The recovery values obtained for most analytes were within the range of 71% and 114% and RSD below 20% (exept Heptahlor, Aldrin, o,p-DDD, p,p-DDD and o,p-DDT, p,p-DDT). The developed method combines a preconcentration with a sample clean-up step due to the extraction of the pigments into the non-polar micelles during the extraction step, and deposition in the intermediate layer of MgSO₄ during the re-extraction step. Full article

Silicon carbide (SiC) has become the material of choice for precision optical systems due to its exceptional optical characteristics. However, conventional anti-reflection strategies for SiC components predominantly utilize deposited thin-film coatings, which are frequently compromised by insufficient environmental robustness and long-term stability concerns. To overcome these limitations, direct nanostructuring of SiC substrates has emerged as a promising alternative solution. This work introduces an innovative graded-index microcone array design fabricated on SiC substrates, achieving superior broadband anti-reflection performance. Our two-step fabrication methodology comprises plasma-induced formation of tunable nanofiber etch masks through controlled argon bombardment parameters, followed by precision reactive ion etching (RIE) for microcone array formation. By systematically varying plasma exposure duration, we demonstrate precise control over nanofiber mask morphology, which in turn enables the fabrication of height-optimized SiC microcone arrays. The resulting structures exhibit exceptional optical performance, achieving an ultra-low average reflectivity of 2.25% across the spectral range of 2.5–8 μm. This breakthrough fabrication technique not only extends the available toolbox for SiC micro/nanofabrication but also provides a robust platform for next-generation optical applications. Unlike conventional thin-film approaches, our nanostructuring method preserves the intrinsic mechanical and environmental durability of the SiC substrate while delivering a favorable optical performance. Full article

Conductive polymer thin films have emerged as a versatile class of materials with immense potential in energy storage and conversion technologies due to their unique combination of electrical conductivity, mechanical flexibility, and tunable physicochemical properties. This review comprehensively explores the role of conductive polymer thin films in three critical energy applications: supercapacitors, batteries, and solar cells. The paper examines key polymers such as polyaniline (PANI), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene) (PEDOT), focusing on their synthesis techniques, structural modifications, and integration strategies to enhance device performance. Recent advances in film fabrication methods, including solution processing, electrochemical deposition, and layer-by-layer assembly, are discussed with regard to achieving optimized morphology, conductivity, and electrochemical stability. Furthermore, the review highlights current challenges such as scalability, long-term durability, and interfacial compatibility, while outlining future directions for the development of high-performance, sustainable energy systems based on conductive polymer thin films. Full article