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.

This study aims to evaluate the effects of installing electrodeless induction lamps on the intact stability of a coastal angling fishing vessel. The objective is to assess whether these alternative lighting systems can improve or maintain vessel stability while offering enhanced energy efficiency compared to conventional metal halide lamps. To achieve this, an 8.55-ton class coastal fishing vessel was selected, and hydrostatic analyses were conducted based on three kinds of lighting configurations: (1) metal halide lamps, (2) electrodeless induction lamps, and (3) a combined system of both. Inclining tests were performed for each condition, and the results were evaluated in accordance with the Standards for Stability and Full Load Waterline of Fishing Vessels and the Safety Standards for Standard Fishing Vessel Types established by the Korean Ministry of Oceans and Fisheries and the Adoption of the international code on intact stability by the International Maritime Organization. The core variables analyzed include the metacentric height (GM), righting lever curves, maximum righting moment and heel angle at maximum moment. These variables were used to assess the intact stability of the vessel under each lighting configuration. Inclination tests and hydrostatic analyses were performed using K-Ship and confirmed that the fishing vessel met all MOF and IMO stability criteria under various loading conditions and lamp configurations. Even when both metal halide and induction lamps were installed, the vessel satisfied the most stringent stability requirements with only a slight reduction in initial metacentric height. These results indicate that replacing or supplementing traditional lamps with induction lamps does not compromise vessel stability.

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.

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.

Wearable electronics have been the focus of considerable interest in various fields, such as human-machine interfaces, soft robotics, and medical treatments, due to their flexibility, stretchability, and light weight. To address the shortcomings of existing metal thin film-based wearable devices, stretchable conductive polymers have been developed. In particular, double networking hydrogels are being actively studied as a polymer with a three-dimensional stereoscopic structure that can be patterned. Nonetheless, they have shortcomings such as poor electrical properties and cumbersome manufacturing processes, making it difficult to apply them in electronic devices. Herein, we report 3D-printed stretchable electrodes enabled by a titanium/polyacrylamide-alginate-based hydrogel nanocomposite. This research suggests the strategy for resolving the challenges of high costs and complex fabrication processes associated with stretchable electrode, providing a solution to accelerate the commercialization of wearable electronic devices.

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.

체인 형태의 코발트(Co) 메조스피어를 템플레이트로 활용하여 금(Au) 및 팔라듐(Pd) 전구체와의 2단계 갈바닉 치환 반응을 통해 비백금 기반의 AuPd 복합 촉매를 합성하였다. NaAuCl4 전구체로부터 합성된 AuPd-Cl(50) 촉매는 높은 비표면적과 다공성 구조를 통해 산소환원반응(ORR)에서 우수한 촉매 활성을 나타냈으며, 상용화된 Pt-20/C 및 Pd-20/C 촉매 대비 낮은 개시(onset) 전위와 높은 한계 전류 밀도 및 향상된 n 값을 보였다. Koutecky-Levich plot 분 석 결과, ORR이 4-전자 전달 메커니즘에 근접함을 확인하였으며, 메탄올 내성과 안정성 실험에서도 우수한 성능을 보였다. AuPd-Cl(50) 촉매는 경제적이고 효율적인 백금 대체 촉매로서 알칼리 연료전지 및 메탄올 기반 연료전지 응 용 가능성을 제시한다.

Super P (SP) is a conductive carbon black that significantly enhances the electrical conductivity of various types of electrodes, making it a widely preferred conductive agent in lithium-ion batteries. By contrast, activated carbon (AC), originally used in capacitors due to its porous structure, is expected to contribute to electrochemical performance through its enhanced interaction with lithium ions. First, the physical properties of both materials were analyzed through various characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) to confirm the increase in electrochemical properties through the combination of SP and AC. Furthermore, the microstructure and electrical properties of the LiFePO4 (LFP) electrode were analyzed, to determine the impact on battery performance. With a 1.15 M LiPF6 in an ethylene carbonate/diethyl carbonate (EC/DEC) electrolyte, the results indicated that SP-only electrodes exhibited the highest conductivity and lowest surface resistance, making them the most effective at maintaining stable electrochemical performance. In contrast, electrodes with only AC showed higher resistance, demonstrating that SP remains superior in improving LFP electrode conductivity, ultimately optimizing lithium-ion battery performance.

본 연구는 EMG(electromyography) 텍스타일 전극 개발을 목적으로 레이어 수의 디자인 및 원단을 다르게 하여 성능 및 신호 획득 안정성을 평가한다. 레이징 및 프레스 공정을 통하여 텍스타일 전극을 제조하며 Layer-0, Layer-1, Layer-2로 레이어 유무 및 수에 따른 결과를 분석했다. 이에 레이어 유무에 따라서는 근활성 측정에 영향을, 수가 많을수록 높은 성능이 나타남을 확인할 수 있었다. Layer-2 구조로 통일하여 5가지의 원단(네오프렌, 스판덱스 쿠션, 폴리에스테르 100%, 나일론 스판덱스, 광목 캔버스)으로 전극을 제조해 실험해 보았다. 성능적인 면에서, 원단의 중 량이 높은 나일론 스판덱스가 높은 성능을 보였으며, 스판쿠션 텍스타일 전극이 근활성도 수득에 높은 안정성을 보 였다. 이에 위 연구는 레이어에 따른 성능 연관성과 전극-피부사이의 닿는 면적 간의 관계 등을 고찰하여 슬리브 전체의 의복압을 늘리는 대신 특정 센서 측정 부위에만 높은 압력을 가함으로 차후 연구에서 레이어의 수 및 물성에 따른 전극의 공학적 설계 가능성을 제시한 의의가 있다.