In this study, we performed optical simulations for two light sources: internal and external electrode light sources. Based on the optical simulation results, we created a practical design to verify the design validity and extract optimal design factors for each light source. The three key geometric variables in the design of a direct-lit flat panel light source are the distance between the two lamps, the distance between the lamps and the reflector, and the number of lamps. These variables significantly impact the optical design and determine various characteristics of the flat panel light source system. In this study, we used a 26 mm distance between the two lamps, a 4.5 mm distance between the lamps and the reflector, and a total of 20 lamps to derive optimal values for these variables. Under these conditions, we created a practical design and evaluated its performance, achieving an excellent flat panel light source with a central luminance of 6,423 nits and a luminance uniformity of less than 5%. This study demonstrates that optical simulation techniques are an effective method for designing a surface-emitting light source system for medical LCDs, demonstrating the feasibility of achieving high performance while maintaining a low cost.

The development of high specific surface area and mesoporous activated carbons is required to improve the electrochemical performance of EDLC. In this study, kenaf-derived activated carbons (PK-AC) were prepared for high-power-density EDLC via phosphoric acid stabilization and steam activation. The pyrolysis behavior of kenaf with respect to the phosphoric acid stabilization conditions were examined via TGA and DTG. The textural properties of PK-AC were studied with N2/ 77 K adsorption–desorption isotherms. In addition, the crystalline structure of PK-AC was observed via X-ray diffraction. The specific surface area and mesopore volume ratio of PK-AC were determined to be 1570–2400 m2/ g and 7.7–44.5%, respectively. In addition, PK-AC was observed to have a high specific surface area and mesopore volume ratio than commercial coconut-derived activated carbon (YP-50F). The specific capacitance of PK-AC was increased from 77.0–99.5 F/g (at 0.1 A/g) to 49.3–88.9 F/g (at 10.0 A/g) with activation time increased. In particular, K-P-15-H-9–10 observed an approximately 35% improvement in specific capacitance at a higher current density of 10.0 A/g compared to YP-50F. As a result, the phosphoric acid stabilization method was confirmed to be an efficient process for the preparation of high specific surface area and mesoporous biomass-derived activated carbons, and the kenaf-derived activated carbons prepared by this process have great potential for application as electrode active materials in high-power EDLC.

Capacitive deionization (CDI) represents a novel technology for the desalination and purification of seawater. Selecting the appropriate electrode material is crucial, with carbon electrodes frequently employed owing to their high specific surface area, extensive porous structure, and environmentally sustainable nature. This study presents a nitrogen-doped porous carbon, derived from household waste, which demonstrates outstanding electrochemical and desalination performance. The purified chitosan was mixed with a specific ratio of CaCO3 and carbonized at 800 °C to produce chitosan porous carbon (CPC-T). To verify the role of the templating agent, its performance was compared with chitosan porous carbon (CPC) prepared by direct carbonization. CPC-T possesses more mesoporous structures (31.25%), shortening ion transport pathways and significantly enhancing charge transfer rates. The nitrogen-rich doping (8.65 at%) provides numerous active sites and excellent conductivity, making it highly appropriate for capacitive deionization applications. Compared to CPC prepared without a templating agent, CPC-T has a higher specific capacitance (101.5 F g− 1 at a scan rate of 2 mV s− 1) and good cycling stability. The CDI cell made from it exhibits a salt adsorption capacity (SAC) of 25.8 mg g− 1 for 500 mg L− 1 NaCl solution at an applied voltage of 1.4 V, retaining 88% capacity after 50 adsorption–desorption cycles, demonstrating excellent desalination regeneration performance. Additionally, among different concentrations of salt solutions, the CPC-T material shows the best desalination performance for the test solution at a concentration of 500 mg L− 1. For different solute ions, the CDI cell with this material as the electrode exhibits excellent desalination performance for Ca2+, with a SAC value of up to 34.02 mg g− 1. This is a self-doped porous carbon material that significantly outperforms traditional carbon-based materials.

Five novel miniature bipolar radiofrequency (RF) electrode tips with distinct tip geometries (spherical, flat, square, and 45° angled) were developed to enable high-precision tissue ablation. Performance was evaluated on saline-soaked tissue, ex vivo bovine liver, and porcine muscle under consistent RF power settings. All designs produced highly localized lesions only a few millimeters across, confirming precise ablation with minimal damage to surrounding tissue. Tip geometry influenced ablation efficiency: a 45° angled tip created ~5 mm lesions at lower power (highest efficiency), whereas an ultra-fine 1.0 mm tip produced ~1 mm lesions but required higher power. These results indicate that the new bipolar RF electrodes achieve precise, localized tissue ablation with minimal surrounding tissue damage and show promise for precise lesion removal in minimally invasive surgery.

Inspired by the recycling approach of electronic waste, within this research paper, we extracted exhausted materials from spent primary zinc batteries and then annealed them in a modified condition, forming a ZnMn2O4/ C composite with a uniform nanoparticles’ porous morphology. The produced material has been examined as a supercapacitor active one, which showed promising electrochemical properties for supercapacitor application. At a current density of 3 A g− 1, it exerted a comparatively significant capacitance of 1696.88 F g− 1 along with a capacity of 807 C g− 1. Furthermore, the fabrication of a flexible all-solid-state symmetric supercapacitor prototype has been accomplished. It exhibited promising initial results that carried a specific energy of 76.75 Wh kg− 1 at a specific power of 333.86 W kg− 1. After 3000 cycles, it maintained an acceptable capacity. Thus, this eco-friendly approach can successfully convert the spent battery material to new value-added materials for supercapacitors in the clean energy area.

Marine biomass (MB) offers an environmentally friendly and readily available carbon source from the ocean. However, the high concentration of alkali and alkaline earth metals (AAEMs) in MB typically reduces the carbon yield and inhibits micropore formation during heat treatment due to catalytic gasification. In this study, we successfully synthesized activated carbon (AC) with a high specific surface area (> 1,500 m2/ g) and significant mesopore content (60%, mean pore size: 3.4 nm) from MB by employing preheating, controlled acid purification, and CO₂ activation. The formation of mesopores in the MB-derived AC was driven by catalytic gasification induced by intrinsic and residual AAEMs during preheating and physical activation processes. We evaluated the potential of the MB-derived AC as an electrode material for electric doublelayer capacitors (EDLCs). The material demonstrated high specific capacitance values of 25.9 F/g and 29.4 F/g at 2.7 V and 3.3 V, respectively, during charge–discharge cycles. These high capacitance values at elevated voltages were attributed to the increased number of solvated ions (e.g., 1.93 mmol/g at 3.3 V) present in the mesopores. Fluorine-19 nuclear magnetic resonance (19F solid-state NMR) analysis revealed a substantial increase in solvated ion concentration within the mesopores of the MB-derived AC electrode at 3.3 V, demonstrating enhanced ion mobility and diffusion. These findings highlight the potential of MB-derived AC as a promising electrode material for high-voltage energy storage applications.

Ni-based superalloys are widely used for critical components in aerospace, defense, industrial power generation systems, and other applications. Clean superalloy powders and manufacturing processes, such as compaction and hot isostatic pressing, are essential for producing superalloy discs used in turbine engines, which operate under cyclic rotating loads and high-temperature conditions. In this study, the plasma rotating electrode process (PREP), one of the most promising methods for producing clean metallic powders, is employed to fabricate Ni-based superalloy powders. PREP leads to a larger powder size and narrower distribution compared to powders produced by vacuum induction melt gas atomization. An important finding is that highly spheroidized powders almost free of satellites, fractured, and deformed particles can be obtained by PREP, with significantly low oxygen content (approximately 50 ppm). Additionally, large grain size and surface inclusions should be further controlled during the PREP process to produce high-quality powder metallurgy parts.

Many recent research efforts have focused on developing high-performance wearable health monitoring systems. This work presents a mechanically stretchable and skin-mountable sensor system based on a conductive polymer composite-based elastic printed circuit board (EPCB) in which a resistive-type composite strain sensor is monolithically integrated. The composite-based EPCB is simply prepared by patterning a silver nanowire (AgNW)/dragon skin (AgNW/DS) composite film in a programmable manner using a direct cut patterning technique. The proposed sensor system was successfully fabricated by directly mounting various components (e.g., microcontroller, circuit elements, light emitting device chips, temperature sensor, Bluetooth module) on the prepared AgNW/DS-based EPCB. The fabricated sensor system was found to be highly stretchable and rollable enough to maintain tight adhesion to the wrist region without significant physical deterioration, even when the wrist was in motion. The wireless sensor system attached to the wrist part enabled us to monitor the wrist motion and surrounding temperature in real time, opening the possible application as a wearable health monitoring platform.

As increasing markets for Lithium‒ion battery (LiB), several environmental issues have attained great attention. Especially, the organic solvent N‒Methyl‒2‒Pyrrolidone (NMP), commonly used in the traditional slurry casting process for fabricating LiB electrodes, will be about to be regulated due to its toxicity and the environmental concerns. Therefore, the production of LiB electrodes by a dry process without using NMP organic solvents is of special interest nowadays. In the dry process, it is generally accepted that 1‒dimensional carbon materials like carbon nanotubes (CNT) are beneficial than conventional carbon conductor such as carbon blacks (CB). However, CB is inevitably included during the CNT production, simultaneously as an impurity. Refining CNT from CNT/CB mixture can cause another cost obviously. On the other hand, there have been limited information to study dispersion of carbon materials in electrode with respect to dispersion method and types of carbon conductor. Here, we systematically test the effect of dispersibility of carbon conductor in electrode according to dispersion method and type of carbon conductors. In addition, effect of CB amount in carbon conductor are also elucidated on manufacturing procedure, properties of electrode and their electrochemical performances.

Conventional bipolar electrodes (typically with round or flat tips) deliver radiofrequency energy in a broad, continuous manner. Their larger tip size and simple shape cause the applied energy to disperse over a wide area, making precise lesion control difficult and often leading to collateral tissue damage. As a result of these design limitations, traditional electrodes exhibit lower energy efficiency and tend to create lesions that unintentionally extend beyond the target area, with excessive thermal spread to surrounding tissues. In contrast, the five newly developed bipolar electrode designs concentrate energy delivery more effectively and provide improved control over lesion size and shape. These novel electrodes demonstrated higher energy efficiency, produced well-confined lesions, and minimized thermal injury to adjacent tissues, thereby overcoming the major drawbacks of conventional designs.

This article describes an efficient electrochemical sensor based on a graphene oxide- manganese dioxide (GO-MnO2) nanocomposite for detecting acetaminophen (AAP) in human fluids. The MnO2- wrapped GO sensing element was prepared by a simple and environmentally friendly co-precipitation method. The prepared GO-MnO2 nanostructure was characterized for its structural, morphological, and functional properties and tested for AAP detection. At a pH of 3, the electrochemical results revealed a high redox process toward AAP due to the transfer of two electrons and protons between the GO-MnO2/ glassy carbon electrode (GO-MnO2/GCE) and AAP. The differential pulse voltammetry (DPV) analytical results showed the precise sensing ability of AAP in a wide linear range [0.125–2000 μM] with superior anti-interference ability. The calculated sensitivity of the GO-MnO2/GCE was 17.04 μAμM−1 cm− 2, and the detection limit (LOD) was 7.042 nM. The sensor exhibited high reliability, good reproducibility, and a good recovery range of 98.47–99.22% in human urine sample analysis.

Herein, the electrochemical technique was employed to detect hydroquinone (HQ) using a modified glassy carbon electrode (GCE) with reduced graphene oxide (rGO) and silver (Ag)-decorated tin oxy-nanoparticles (SnONPs) to form Ag@SnONPs/ rGO nanocomposites (NC). The Ag@SnONPs/rGO nanocomposites were morphologically characterized using multiple analytical methods such as XRD, Raman, XPS, HR-SEM, and HR-TEM. This study revealed that Ag@SnONPs/rGO-NC exhibits excellent conductivity due to the presence of rGO that provides potential π–π interactions with SnONPs, while Ag enhances electron-transfer kinetics. This facilitates efficient charge transport within the sensor, thereby improving HQ adsorption. The key advantages of the sensor demonstrate a concentration of 0.5–200 μM, and a low detection limit value of 0.010 μM, and a high sensitivity value of 6.0746 μA μM−1 cm2. Under optimal conditions, the Ag@SnONPs/rGO sensor may be used to determine HQ and its concentration using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The Ag@SnONPs-rGO/GCE sensor demonstrated excellent reproducibility, repeatability, and stability. Moreover, the suggested bimetallic nanocomposite effectively determined the presence of HQ in water and cosmetic samples.

Fiber supercapacitors have attracted significant interest as potential textile energy storage devices due to their remarkable flexibility and rapid charge/discharge capabilities. This study describes the fabrication of a composite fiber supercapacitor (FSC) electrode through a multi-shell architecture, featuring layers of carbon nanotube (CNT) conductive shells and MnO2 nanoparticle active shells. The number of layers was adjusted to assess their impact on FSC energy storage performance. Increasing the number of shells reduced electrode resistance and enhanced pseudocapacitive characteristics. Compared to the MnS@1 electrode, the MnS@5 electrode exhibited a high areal capacitance of 301.2 mF/cm2, a 411% increase, but showed a higher charge transfer resistance (RCT) of 701.6 Ω. This is attributed to reduced ion diffusion and charge transfer ability resulting from the thicker multi-shell configuration. These results indicate that fine-tuning the quantity of shells is crucial for achieving an optimal balance between energy storage efficiency and stability.

세계적인 탄소중립 정책 추진과 수소 에너지 수요 증가에 따라 고분자 전해질 수전해 및 연료전지 기술 개발이 활발히 이루어지고 있다. 해당 기술의 핵심 소재인 과불소계 술폰산 이오노머는 우수한 전기화학적 특성과 화학적 안정성을 가지고 있지만, 높은 제조비용, 한정된 공급망, 강화되는 환경 규제와 같은 문제로 인해 효과적인 재활용 및 재제조 기술이 요구되고 있다. 본 연구에서는 초임계 분산 기술을 통해 전해질막 및 막-전극접합체의 제조과정에서 발생하는 고활성을 갖는 전해질막 스크랩을 연료전지 전극바인더로 재제조하는 방법을 제시하고자 한다.

Gold nanoparticles (Au NPs) decorated carbon nanofibers (CNFs) have been prepared by an electrospinning approach and then carbonized. The prepared Au-CNFs were employed to modifying a screen printed electrode (SPE) for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Au NPs are uniformly dispersed on carbon nanofibers were confirmed by the structure and morphological studies. The modified electrodes were tested in cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA) to characterize their electrochemical responses. Compared to bare SPE, the Au-CNFs/SPE had a better sensing response to AA, DA, and UA. The electrochemical oxidation signal of AA, DA and UA are well separated into three distinct peaks with peak potential separation of 280 mV, 159 mV and 439 mV between AA-DA, DA-UA and AA-UA respectively in CV studies and the corresponding peak potential separation in DPV studies are 290 mV, 166 mV and 456 mV. The Au-CNFs/SPE has a wide linear response of AA, DA and UA in DPV analysis over the range of 5–40 μM ( R2 = 0.9984), 2–16 μM ( R2 = 0.9962) and 2–16 μM ( R2 = 0.9983) with corresponding detection limits of 0.9 μM, 0.4 μM and 0.3 μM at S/N = 3, respectively. The developed modified SPE based sensor exhibits excellent reproducibility, stability, and repeatability. The excellent sensing response of Au-CNFs could reveal to a promising approach in electrochemical sensor.

Graphitic nitrogen-doped carbon film/nanoparticle composite, in which the films were wrapped and separated by the nanoparticles, was prepared through a simple co-calcination route. Due to its unique porous structure and improved nitrogen content, the as-prepared electrode material could exhibit high specific capacitances of 317.5 F g− 1 at 0.5 A g− 1 and 200.0 F g− 1 at 20 A g− 1, and stable cycling behavior with no capacitance decline after 10,000 cycles in three-electrode system. When assembled in two-electrode capacitor, its specific capacitance could be well kept at 265.5 F g− 1 at 0.5 A g− 1, and thus the supercapacitor with a high energy density of 9.22 Wh kg− 1 was obtained. The superior energy storage properties of the as-prepared material indicate its promising application as high-performance carbon-based electrode for supercapacitors.