Solution-processed graphene fibers are commonly fabricated by wet spinning of a liquid-crystalline (LC) graphene oxide (GO) dope, owing to the homogeneous aqueous dispersion of GO, strong hydrogen bonding, and nematic self-assembly. A straightforward route has thus been established for the formation of graphene fibers. However, during coagulation and subsequent chemical reduction, GO sheets consolidate into densely stacked fiber architectures, which often develop geometric non-uniformity due to anisotropic shrinkage during solvent exchange and reduction. Following chemical reduction, restacking and structural deformation occur, leading to the formation of large voids and ion-inaccessible volumes that reduce the ion-accessible surface area, thereby limiting their applicability in high-performance supercapacitors. Herein, deformation-free circular graphene fibers (GFs) are introduced via wet spinning using a hybrid ammonia-based graphene oxide (AGO)–reduced graphene oxide (rGO) composite dope. The AGO precursor preserves the intrinsic LC assembly characteristics of GO while offering improved dispersion stability and tunable intersheet interactions. The rGO component is engineered to retain stable aqueous dispersibility, enabling homogeneous co-dispersion with AGO sheets. Incorporation of rGO suppresses excessive LC-driven stacking and moderates solvent–coagulant exchange during extrusion, enabling rapid and homogeneous coagulation. In contrast to the layered architecture derived from conventional GO spinning, the rGO-rich hybrid fibers exhibit uniformly organized porous structures with effective pore sites. The mechanically rigid and chemically stable rGO forms a percolated structural framework that supports homogeneous electrical conductivity and mechanical strength while preserving high circularity with axial and radial uniformity. Consequently, the optimized AGO–rGO fibers exhibit enhanced electrical conductivity (567 S cm–1 after post-drawing) and improved electrochemical capacitance, demonstrating strong potential for high-performance fiber-shaped or wearable supercapacitors.

In the controlled synthesis of biomass-derived porous carbon materials, effective pretreatment strategies play a critical role in modulating the chemical activation process and optimizing material performance. However, existing studies predominantly focus on the macroscopic structural changes induced by pretreatment, often overlooking the important role of chemical composition evolution during activation. Herein, a coconut shell-based acidic hydrothermal pretreatment was designed to precisely control the evolution of the primary pore structure alongside the enhanced retention of oxygen species in the hydrochar. Subsequent chemical activation successfully yields a high-performance carbon material with a well-defined hierarchical porous structure. This material exhibits a high specific surface area of 1963 m2 g⁻1 and delivers an outstanding specific capacitance of 420 F g⁻1 at a current density of 0.5 A g⁻1. When assembled into a solid-state supercapacitor, the device achieves a high energy density of 12.97 Wh kg⁻1. It also demonstrates excellent cycling stability, retaining 97.02% of its initial capacitance after 10,000 cycles at 10 A g⁻1, along with a high Coulombic efficiency of 99.84%. Our findings reveal that appropriate acidic hydrothermal pretreatment not only establishes a continuous primary pore network within the precursor—facilitating the deep diffusion and uniform reaction of the activating agent—but also enhances activation efficiency synergistically through the anchoring effect of oxygen species. This work provides new insights and experimental support for the rational design of high-performance biomass-derived carbon materials.

In laser powder bed fusion (L-PBF), a metal powder–based additive manufacturing process, pure titanium powders rely on expensive gas-atomized spherical powders, which poses a significant limitation of material cost. In contrast, non-spherical titanium powders are more cost-effective but their application in L-PBF is restricted their use due to poor flow property and high oxygen content. In this study, a powder mixing strategy with spherical titanium and hydrophobic SiO2 nanoparticle is proposed to improve the flowability and process stability of non-spherical Ti powders. After evaluating flow properties at various mixing ratios, a spherical-to-non-spherical Ti ratio of 4:6 was selected, with SiO2 nanoparticles added during mixing. The uniform distribution of oxide nanoparticles on the powder surfaces was confirmed by SEM and EDS. A maximum relative density of 99.7% was shown by specimens made with L-PBF under various processing parameters. The specimens obtained a tensile strength of 762.6 ± 3.8 MPa and an elongation of 22.1 ± 0.7% at a volumetric energy density of 71.4 J/mm³. This study demonstrates the application of low-cost non-spherical Ti powders in L-PBF is feasible and presents an effective way to simultaneously increase process stability and economic efficiency in titanium additive manufacturing.

Carbon nanotubes (CNTs), as one-dimensional carbon nanomaterials, exhibit exceptional electrical conductivity, mechanical strength, and chemical stability, making them highly suitable for applications in energy storage and wearable devices. Despite Floating catalyst chemical vapor deposition (FCCVD) is a scalable, one-step method capable of fabricating CNT aerogels, fibers, and sheets. A key advantage of FCCVD lies in its tunability of CNT properties such as aspect ratio, crystallinity, wall number, and chirality during synthesis, which are critical parameters for optimizing electrochemical performance. However, as-synthesized CNTs typically contain impurities such as residual catalysts, graphitic impurities and amorphous carbon, necessitating post-synthesis purification and functionalization to improve their compatibility with polymer matrices and composite systems. CNTs are widely used as active materials and conductive networks in batteries and supercapacitors, contributing to enhanced both energy and power density. Despite these advantages, CNT based devices still face challenges including variability in properties, cost, scalability, and integration issues such as structural non-uniformity, and inconsistent assemblies that limit cycle life and reproducibility. Various purification and functionalization strategies have been developed to improve the CNT quality for device integration. This review outlines FCCVDbased CNT synthesis, purification and functionalization methods, and highlights the critical roles CNTs play in advancing next-generation lithium-ion batteries and supercapacitors.

AlGaN/GaN high-electron-mobility transistors (HEMTs) are widely employed in power electronics and high-frequency systems because of their high-speed switching and high-power capabilities. However, conventional structures suffer from issues including mobility degradation and device deterioration at elevated temperatures, as well as current collapse and increased gate leakage under high-voltage operation. To address these issues, this work proposes metal-oxidesemiconductor HEMTs (MOS-HEMTs) incorporating an Al2O3/HfO2 stacked gate dielectric. Al2O3 provides excellent chemical stability at the AlGaN interface, reducing interface trap density, while its wide bandgap suppresses electron tunneling and lowers gate leakage. In contrast, HfO2 offers a high dielectric constant, improving oxide capacitance and enhancing charge control even at the same physical thickness. The stacked Al2O3/HfO2 structure leverages the complementary advantages of both materials, enabling threshold voltage stabilization and effective suppression of leakage current. This design mitigates the thermal and electrical reliability concerns of conventional HEMTs and paves the way for high-performance GaN-based devices suited to next-generation high-speed, high-power applications such as artificial intelligence, 5G communication, and LiDAR systems.

In this study, a thermal-fluid-structure coupled analysis was performed to improve the thermal performance of a burner for a coal gasification power plant. After combustion analysis, an average temperature of 1,400°C was obtained, closely matching the actual coal gasification system environment. The highest burner tip surface temperature, 887°C, was achieved at the analysis variable, a coal fines inflow velocity of 8m/s. This temperature was mapped to a thermal-structural analysis model, and by increasing the radius of the cooling channel inside the burner to 5 mm, the analysis confirmed a reduction in thermal stress of approximately 20%. In particular, changing the material to HP50-Nb resulted in significantly superior cooling efficiency compared to Inconel 718 without any cooling channel design. The results of this study will be useful for the optimal design of coal gasification facilities as well as for improving the durability of the facilities.

Incorporating nanotechnology into cement composites significantly improves mechanical properties such as strength, toughness, and durability. Graphene, with high tensile strength and large surface area, shows great promise as a nanofiller, but its hydrophobicity complicates its dispersion in cement matrices. This study used a graphene-cellulose nanofiber (G@ CNF) hybrid filler to ensure a highly uniform dispersion within the cement microstructure. The hybrid filler acts as a bridge and efficiently fills voids within the matrix. The planar structure of graphene also provides nucleation sites for hydrated products, leading to a denser microstructure. The cement composite containing 0.01 wt.% graphene exhibited a compressive strength of 72.7 MPa, representing a 47.5% improvement over the plain cement. Furthermore, the resulting cement demonstrated enhanced water resistance compared to graphene oxide-reinforced-cement. This approach offers a cost-effective and sustainable way of producing high-strength, durable cement composite.

Activated carbons with high micro-/meso-porosity derived from biomass are increasingly popular as sustainable materials. However, these carbons often struggle with low carbon content and limited structural stability. Here, we present Mongolian anthracite-based carbons synthesized via carbonization and chemical activation. Structural analysis shows that Act-MRA samples develop plate-like morphologies with reduced particle size and greater porosity as KOH content increases. The Act-MRA samples have a disordered carbon structure with small graphitic domains, even at higher KOH ratios without significant crystal defects. Notably, Act -MRA3 displays a large specific surface area and high pore volume, with welldeveloped micropores (7–20 Å) and mesopores (20–50 Å) that expand as KOH ratios rise. Electrochemical tests indicate that Act -MRA3 achieves high specific capacitance (220.6 F/g at 5 mV/s) and rate retention (~ 80% at 300 mV/s), owing to its optimized pore structure and enhanced ion transport. These findings underscore the importance of tailored pore structures and defect engineering in boosting activated carbon performance for energy storage.

Graphene materials show great potential in the field of supercapacitors, but their tendency to agglomerate leads to a significant decrease in performance. Herein, manganese dioxide intercalated graphene oxide precursor was prepared using the modified Hummer method. During pyrolysis, manganese dioxide can not only act as a separator to prevent graphene aggregation but also undergo redox reactions with graphene to obtain oxygen-rich mesopore graphene (OMG). Benefiting from the mesoporous structure and abundant oxygen-containing functional groups, the OMG-600 electrode shows a specific capacitance of 248.67 F g− 1 at 0.5 A g− 1 and good electrochemical stability (92.25% capacitance retention after 10,000 cycles). Moreover, the assembled OMG-600//OMG-600 symmetric supercapacitor delivers an energy density of 17.69 Wh kg− 1 and superior electrochemical stabilization in 1 M Na2SO4 electrolyte.

With high redox activity, superior conductivity, abundant pores, and large specific surface area, nitrogen-doped graphitic carbon featuring a hierarchically porous structure is regarded as ideal electrode material for supercapacitors. In this work, hierarchically porous nitrogen-doped graphitic carbon (PG-PZC50) was fabricated via non-solvent induced phase separation and high-temperature calcination processes. SEM images showed its three-dimensional network structure, with abundant macro- and mesopores distributed throughout. XRD and Raman spectra confirmed the phase purity and graphitic nature of the as-prepared material, while XPS revealed its surface elemental composition, especially the content and doping states of nitrogen atoms. The graphene oxide-induced three-dimensional network, combined with the mesoporous structure of metalorganic framework-derived N-doped carbon particles, creates abundant migration channels and a large adsorption surface area for the electrolyte ions. Benefiting from its hierarchically porous structure and high nitrogen-doping content, the formed PG-PZC50 reached high specific capacitances of 499.7 F g− 1 at 0.1 A g− 1 and 179.6 F g− 1 at 20 A g− 1. Notably, the material also demonstrated robust cyclic stability with no capacitance loss after 10,000 charge–discharge cycles. The proposed synthetic strategy provides new ideas for the facile and reproducible construction of nitrogen-doped graphitic carbon with 3D hierarchically porous structure and high capacitive performances.

This research highlights the use of a WO3: CeO2@MXene/gC3N4 (MGWC) nanodisk as a versatile material. MGWC demonstrates efficient photocatalytic degradation of moxifloxacin (MOF) in water under sunlight and also shows great promise for high-performance supercapacitor applications. MGWC was synthesized using a modified hydrothermal method and thoroughly characterized using various techniques. The MGWC showed a band gap energy of 2.79 eV determined through UV–Vis DRS analysis and an average crystallite size of 39.6 nm calculated from XRD. A promising photocatalytic activity was observed for the degradation of MOF, outperforming other photocatalysts. Additionally, preliminary studies examined variations in catalyst concentration, pH, kinetics, electrolytes, scavengers, reusability, and TOC, contributing valuable insights. Under optimal conditions, the MOF achieved almost complete degradation, reaching about 99.7% within 180 min using the MGWC photocatalyst. Additionally, MGWC exhibits promising potential in supercapacitor applications. EIS and CV studies have been used to examine MGWC’s exceptional charge transfer properties. CV tests confirm the pseudocapacitive nature of MGWC electrodes. GCD studies of MGWC exhibit a high specific capacitance of 551 F/g at 1 A/g with incomparable capacitance retention of 98.1% over 10,000 cycles. This research not only aids in reducing emerging environmental pollutants but also sets the stage for sustainable energy solutions.

With the increasing demand for flexible electronic devices, smaller and lighter flexible supercapacitors have gained significant research attention. Among the various materials, self-supporting reduced graphene oxide (rGO) paper has emerged as one of the most promising electrode materials for supercapacitors due to its low cost, high chemical/thermal stability, and excellent electrical conductivity. Nevertheless, a major drawback of rGO paper is the limited ion diffusion between stacked rGO layers, hindering the effective formation of electrochemical double-layer at the electrode/electrolyte interface. In this study, we prepared the rGO paper derived from ball-milled followed-by water oxidation process for reducing the sheet size. The smaller-sized rGO sheets facilitated ion transport between graphene layers, promoting efficient electric double-layer formation. Moreover, the increased presence of edge planes in ball-milled rGO sheets achieved high capacitance, further enhancing the performance of rGO as an electrode material. Notably, the 2-BMOX rGO paper obtained from ball-milling and wet-oxidized graphite exhibited a capacitance of 117.9 F/g in cyclic voltammetry (CV) and 128.6 F/g in galvanostatic charge–discharge (GCD) tests, approximately twice that of conventional rGO. Additionally, the capacitance retained 91% of its initial performance after 2,000 cycles, indicating excellent cycling stability.

Water contamination caused by heavy metal pollutants from industrial activities remains a pressing environmental concern. This study reports the development of a novel carbon paste electrode (CPE) modified with ethylenediaminetetraacetic acid (EDTA), polyvinyl alcohol (PVA), and multi-walled carbon nanotubes (MWCNTs) using a mechanochemical method for the electrochemical detection of Cu(II) ions. The modified electrode was thoroughly characterized to evaluate its functional groups, morphology, crystallinity, elemental composition, and electrochemical properties. Electrochemical measurements were performed using cyclic voltammetry (CV) and square-wave anodic stripping voltammetry (SWASV) under optimized conditions in 0.1 M NH₄Cl at pH 5. The EDTA/PVA/MWCNT-CPE exhibited a low detection limit (0.0457 μM), a wide linear range (0.1–2.7 μM), and excellent reproducibility (RSD = 0.51%), repeatability (RSD = 0.43%), and stability (95% retention after six days). Selectivity tests demonstrated high recovery for Cu(II) (99.7%) and Hg(II) (99.89%) with minimal interference. This simple, cost-effective sensor offers high sensitivity and selectivity, making it a promising candidate for Cu(II) detection in environmental monitoring applications.

This study investigates the dynamic characteristics of telescopic booms for special-purpose vehicles fabricated with giga-grade ultra-high strength steel (UHSS) plates that have been increasingly adopted in industrial applications. In thin-walled structures such as telescopic booms, dynamic properties – particularly natural frequencies – are critical factors directly related to structural safety. Accordingly, the dynamic characteristics were experimentally measured and analyzed for identically designed booms fabricated using either imported giga-grade steel (Strenx 960) or domestic giga-grade steel (ATOS 980), both of which are widely available in the domestic market. The natural frequencies were identified based on frequency response functions (FRFs), and the corresponding mode shapes were obtained through experimental modal analysis. The results show that the nominal yield and tensile strengths provided by the manufacturers and the measured natural frequencies and mode shapes exhibit highly similar characteristics. These experimental findings confirm that the domestic UHSS exhibits a level of dynamic performance comparable to that of the imported steel of the same grade. Consequently, the results support the feasibility of applying domestic giga-grade UHSS to telescopic boom structures and highlight its potential contribution to material localization and enhanced design competitiveness in the domestic special-purpose vehicle industry.

Ultra-high temperature ceramics (UHTCs) exhibit extremely high melting points (> 2,500 °C) and maintain structural stability under severe conditions. However, their intrinsic brittleness and oxidation vulnerability limit their direct application in aerospace components exposed to extreme environments. To overcome these limitations, UHTC-based composites reinforced with secondary phases such as ZrO2 are required to improve fracture toughness and oxidation resistance. The polymer infiltration and pyrolysis (PIP) process provides a promising fabrication route for such composites, offering densification of porous matrices with liquid precursors while maintaining uniform microstructures. Here, we report a novel zirconia precursor (PZC-12) synthesized through a sol-gel reaction of zirconium propoxide with acrylic acid (1:2 molar ratio). The liquid precursor exhibited a suitable viscosity (~518 cP) and enabled dual crosslinking via hydroxyl condensation combined with radical polymerization of vinyl groups. Consequently, effective thermal curing was accomplished upon heating at 80 °C for 12 h. This strategy minimized premature decomposition and achieved a high ceramic yield of 52.7 %. Pyrolysis at 600 °C in air produced nanosized t-ZrO2, which transformed into m-ZrO2 with grain growth at higher temperatures. Applied in PIP, a ZrB2-ZrO2 composite was successfully fabricated, demonstrating that dual crosslinking is critical for high-yield, reliable PIP-based UHTC composites.

This study aims to evaluate the high-precision positioning capability and lane-level localization accuracy of low-cost RTK-GNSS(Real- Time Kinematic Global Navigation Satellite System) technology. This study compares the positioning accuracy and lane-level localization performance of a low-cost RTK-GNSS module with those of a commercial high-precision receiver under identical conditions. Specifically, the root-mean-square, lateral offsets from HD-map(High-Definition Map) lane centerlines, and lane-change detection rates were evaluated to examine the applicability of the module to advanced mobility systems. Based on experiments conducted using a two-axis linear motion device and actual-vehicle tests on expressways, the low-cost RTK-GNSS module demonstrated precision positioning and lane-level localization comparable to that of a commercial high-precision receiver under the same test conditions. In the precision-positioning evaluation, the maximum positioning error of the low-cost module is approximately 2 cm, which is larger than that of a commercial receiver. Nevertheless, its average error generally remained within the typical range of 1–2 cm, which is the expected range for fixed RTK solutions in opensky environments. Furthermore, the difference in the lane-level localization accuracy between the low-cost and high-precision modules remained at approximately 1 cm. Although the low-cost RTK-GNSS module employs fewer receiver channels compared with commercial high-precision units, the integration of the RTK-OMEGA solution, which supports robust integer ambiguity resolution and is a key element of RTK correction, enables it to perform comparably to a commercial module under identical test conditions. The performance-evaluation indicators and methodologies presented herein are expected to provide a meaningful foundation for future studies aimed at ensuring the reliability and safety of cost-effective RTK-GNSS technologies.

This study experimentally evaluated the flexural behavior of reinforced concrete (RC) beams incorporating a high-performance cementitious composite (VC) with 1.0 vol.% Vectran fibers. Three-point bending tests were conducted on a reference high-strength concrete beam (RCB) and two VC beams (VCB-1, VCB-2). Compared with RCB, the maximum load increased by +19.8% (VCB-1) and +9.0% (VCB-2), while the yield load rose by +18.9% and +16.0%, respectively. The ductility index (Δu/Δy) improved from 1.89 (RCB) to 5.22 (VCB-1), confirming the crack control effect based on multiple micro-cracking. The improved performance indicates not only enhanced flexural capacity and ductility but also suggests the potential for carbon-neutral structural design through material reduction and service-life extension enabled by the Vectran fiber-reinforced composite system.