In this paper, the structural optimization and experimental validation of lightweight, high stiffness rollers for roll-to-roll(R2R) processing of lithium metal electrodes are presented. Precise dimensional control of electrode thickness below 50㎛ is essential for next-generation high energy density batteries, yet elastic recovery during rolling hinders the achievement of target specifications. To address this challenge, finite element(FE) analysis was employed to determine the optimal rolling gap and roller geometry, and the results were verified through R2R experiments. Simulations indicated that a rolling gap of 153㎛ yielded a final sheet thickness of about 49.6㎛, meeting the design requirement. Experimental results confirmed the validity of the numerical model, with thickness measurements deviating less than ±10% from FE analysis predictions. These findings demonstrate that the proposed roller design not only ensures thickness precision but also improves system efficiency, offering practical guidelines for scalable lithium metal electrode manufacturing.

본 연구는 도로변 완충녹지에서 녹지구조와 공기 중 미세먼지 농도(지상 1.5m 지점)를 조사하여 미세먼지 농도에 영향을 주는 완충녹지의 구조적 요인을 파악하고자 하였다. 총 10개소의 완충녹지에서 측정된 미세먼지 농도를 도로측 미세먼 지 농도와 비교한 상대농도지수(Relative PM10 Index: RPM10)를 산출하였다. RPM10이 양의 값이면 녹지의 농도가 더 낮고, 음의 값이면 녹지의 농도가 더 높음을 의미한다. 미세먼지 농도 측정 결과 도로측과 비교하여 녹지측의 미세먼지 농도가 전반적으로 높았다. 녹지구조 변수와 상관분석 결과 RPM10은 관목층 피도, 전체 수목 피도, ㎡당 관목층 체적과 양의 상관성이 유의하였고, 평균 수고, 지하고, 식재 밀도, 교목층의 피도와 ㎡당 체적 등은 유의한 상관성을 확인할 수 없었다. 또한 완충녹지 배후공간이 막혀있는 곳의 RPM10이 비어있는 곳보다 낮은 차이가 인정되었 다. 회귀분석 결과 완충녹지 배후공간이 막힌 곳에서는 빈 곳보다 RPM10이 낮아지고(B=-.123, P=.000), 관목층 체적 (B=.674, P=.004)과 수목 지하고(B=.072, P=.015)가 증가하면 RPM10이 높아지는 것으로 파악되었다. 완충녹지에서 측정된 더 높은 미세먼지 농도는 녹지에서 미세먼지가 차단·정체된 결과로 판단된다. 정체된 미세먼지는 녹지 내부에서 제거되어 외부 미세먼지 농도 감소에 기여한다. 분석결과 관목층 식재 및 지하고가 낮은 교목·아교목층 수목의 배치는 미세먼지의 흐름 차단에 유리한 것으로 나타났다. 이러한 결과는 향후 도로변 완충녹지 조성뿐만 아니라 도시공원·녹지 계획의 수립 시 미세먼지 저감을 위한 식재 전략으로 고려될 수 있다.

This study investigates the structural mechanisms underlying user acceptance of generative AI services by integrating cognitive and affective dimensions of user experience. Based on the Technology Acceptance Model, Expectation–Confirmation Theory, and flow theory, a research model was developed and tested through an online survey of 387 Korean users with more than three months of experience. Structural equation modeling confirmed that cognitive and affective responses significantly influence satisfaction and trust, which in turn predict loyalty, with trust showing the strongest direct effect. Satisfaction and trust also mediated these relationships, while flow strengthened the satisfaction–loyalty path and resistance to technology was not significant. These findings highlight the importance of incorporating emotional and experiential factors alongside functional aspects. Practical implications suggest that fostering trust, engagement, and perceived value is essential for sustaining loyalty in generative AI services.

The 2024 Noto Peninsula Earthquake in Japan caused significant damage to wooden structures due to strong ground motion and widespread liquefaction. This study examines the damage patterns observed in wooden houses and analyzes the underlying structural vulnerabilities that contribute to these patterns. Key findings include standard failure modes such as foundation settlement, soft-story collapse, torsional deformation, and joint failure. The evolution of Japan’s seismic design standards has been reviewed, highlighting the importance of balanced wall distribution, reinforced connections, and lightweight roofing systems. Based on field investigations, this study systematically classifies the types of seismic damage in wood structures. It develops a qualitative performance curve that visually illustrates structural behavior in terms of inclination, seismic damage patterns, and repairability. Furthermore, a seismic damage taxonomy is proposed to infer the causes of damage through logical links between observed failure patterns and structural vulnerabilities. This research establishes a practical foundation for the seismic design and retrofit strategies of wood structures, ultimately contributing to the advancement of earthquake-resilient construction practices.

This study analyzed the structural performance of a microalgae-based lightweight ecological integration system for large-span structures to achieve carbon neutrality. To address the load problems of existing soil-based ecological systems, a lightweight system utilizing microalgae bioreactors was proposed, and structural performance was evaluated for four types of large-span structures: truss, arch, dome, and cable structures. Structural analysis results through finite element analysis showed that the proposed system achieved a 70% load reduction effect compared to existing systems, with structural performance improvements including 35-40% reduction in maximum deflection, 30-35% reduction in maximum stress, and 25-30% increase in natural frequency. Environmental performance analysis confirmed CO₂absorption capacity of 12-18 kg per m² annually and PM2.5 reduction effects of 15-25%. Economic analysis results indicated that benefits of 3.95-6.7 million KRW per year are generated for a 1,000 m²reference area, creating cumulative benefits of 179.75-227.5 million KRW over 25 years. Verification through the German BIQ House case confirmed CO₂reduction performance of 6 tons per year for 200 m², demonstrating the practical applicability of the system. This study presented the potential of an innovative ecological integration system that can ensure structural safety of large-span structures while simultaneously contributing to carbon neutrality.

강풍에 대한 피해가 증가하면서 시설물의 취약도를 예측하여 대응하는 것이 필요하다. 이때, 풍속의 변동성을 고려하여 확률 론적 예측이 필요하여 물리 기반 인공신경망(PINN) 기반의 기초적인 확률론적 예측 모델을 개발하였다. 입력변수를 마르코프체인 몬 테카를로 시뮬레이션을 통해 랜덤 샘플링하여 이를 PINN 모델로 입력하고, 물리식 기반의 손실함수를 통해 신호등을 대상으로 취약 도를 예측하였다. 모델을 통해 예측한 결과 신호등에서 파손이 발생할 수 있는 신호 접합부와 지면 접합부에 대해 확률적으로 취약도 를 산출할 수 있었고, 이를 기반으로 신호 접합부가 더 취약함을 확인할 수 있었다. 기초 모델로 물리식 만을 기반으로 예측하여 얻은 결과로 추후 실측 데이터를 통해 학습과 검증을 거쳐야하나 충분히 강풍에 의한 시설물 취약도를 예측할 수 있으며 이러한 예측에 확 률론적 모델이 유용함을 확인하었다.

This study experimentally and numerically evaluated the fire risks and structural vulnerabilities of tunnel-type noise barriers (hereinafter referred to as hereinafter referred to as soundproof tunnels). In Korea, soundproof tunnels are typically constructed using combustible polymeric materials such as polymethyl methacrylate (PMMA) and polycarbonate (PC) for noise reduction and lightweight design. However, due to their enclosed structural characteristics, concerns have been raised regarding heat and smoke accumulation as well as the rapid spread of fire. In this study, fire scenarios were established by varying structural conditions, including roof opening ratios and the presence or absence of central partitions, and analyzed using the Fire Dynamics Simulator (FDS). The results demonstrated that PMMA exhibited a lower thermal decomposition temperature and a higher heat release rate, indicating a higher level of fire risk, while PC showed superior fire resistance with higher decomposition temperature and delayed ignition properties. PMMA rapidly exceeded the critical thresholds for temperature and radiative heat flux, resulting in complete combustion. Central partitions were found to accelerate smoke spread, whereas side or roof openings facilitated smoke discharge to the exterior, contributing to fire suppression and improving life safety. In conclusion, this study confirmed that the fire risks of soundproof tunnel are jointly influenced by the combustion characteristics of the materials and the structural conditions. The findings are expected to serve as fundamental data for material selection and design standard improvements in future soundproof tunnel fire safety.

본 연구는 교육서비스 기업에 종사하는 강사를 대상으로 교육조직 시민행동과 기업의 사회적 책임, 전 문직업적 정체성 및 일의 의미의 구조적 관계를 실증적으로 검증하고자 하였다. 이를 위해 일반 교습학원 과 기타 교육기관에 소속된 강사를 대상으로 온라인과 오프라인 설문을 시행하였고, 총 391명의 자료를 최종 분석에 활용하였다. 주요 연구 결과를 요약하면 다음과 같다. 첫째, 이 연구에서 설정한 구조모형에 대한 적합도가 모두 양 호하게 나타나 각 변수 간의 구조적 관계를 타당하게 설명할 수 있는 것으로 검증되었다. 둘째, 강사의 교 육조직 시민행동에 직접적인 영향을 미치는 요인은 기업의 사회적 책임, 전문직업적 정체성, 그리고 일의 의미로 확인되었으며, 이들 변수 간의 관계 또한 유의미한 영향을 갖는 것으로 분석되었다. 특히 기업의 사회적 책임은 강사의 전문직업적 정체성과 일의 의미에 긍정적인 영향을 주었고, 전문직업적 정체성은 일의 의미 인식에 직접적인 영향을 미치는 것으로 나타났다. 마지막으로 기업의 사회적 책임과 교육조직 시민행동의 관계에서 전문직업적 정체성과 일의 의미의 매개효과를 확인하였다. 이를 바탕으로 교육서비 스 조직 내 시민행동 증진을 위한 논의와 후속연구를 위한 제언을 제시하였다.

TiO2/CNT/GO heterostructure nanocomposite was synthesized by solvothermal method for the removal or degradation of methylene blue (MB). The physical and chemical characteristics were assessed by various characterization techniques such as scanning electron microscopy (SEM) confirmed the external and internal morphology of the heterostructure materials with irregular shapes. Transmission electron microscopy (TEM) showed that the internal structure was preserved after incorporating CNTs and GO into TiO2, and the average particle size distribution was determined using an SEM histogram with an average particle size of 85.5 nm. Energy dispersive X-ray spectroscopy (EDS) was performed to evaluate the elemental mapping of heterojunction confirm the presence of C, O, and Ti. X-ray diffraction (XRD) revealed a crystalline nature and the size of as synthesized material was calculated as 17.08 nm. UV–vis spectroscopy (UV–vis) was conducted to observe the optical behavior and light scattering phenomena of heterostructure materials. Various factors, such as different doses of heterostructure (0.1, 0.2, and 0.3 g), dye concentration (10, 20, and 30 ppm), irradiation time (0, 30, 60, 90, and 120 min), were carried out at 25 °C. The TiO2/ CNT/GO heterostructure induced 91% methylene blue (MB) degradation in 120 min with superior cycling stability after regeneration for four cycles. The optimal reaction conditions were adopted to obtain the highest degradation rate using 0.2 g of the heterostructure, 30 ppm MB concentration, 120 min of light irradiation, and 25 °C reaction temperature. The TiO2/ CNT/GO photocatalyst exhibited enhanced kinetic performance, catalytic stability, structural reliability, and reactivity for 91% degradation efficiency of MB.

본 연구는 노인환자를 돌보는 요양병원이라는 특수한 환경에서 정서 적, 윤리적 요인이 간호업무수행에 미치는 영향을 분석하고자 요양병원 간호사의 공감역량과 윤리적민감성, 환자중심간호, 간호업무수행 간의 구 조적 관계를 파악하고, 간호업무수행 향상을 위한 이론적, 실무적 기초자 료를 제공하기 위해 수행되었다. 연구대상은 국내 요양병원간호사 230명 을 편의표집 하였으며, 연구결과로 모형 적합도는 χ²/df=165.517, CFI=.945, TLI=.928, RMSEA=.092로 양호하였으며, 공감역량은 윤리적민 감성(β=.478, p<.001)과 환자중심간호(β=.716, p <.001)에 유의미한 영향을 미쳤으며, 간호업무수행(β=.431, p <.001)에는 간접적으로 영향을 미치는 것으로 나타났다. 윤리적민감성은 간호업무수행(β=.188, p <.001)에, 환자 중심간호는 간호업무수행에 매개요인으로 작용하였다(β=.477, p <.001). 간호업무수행 향상과 환자중심간호를 실천하기 위한 간호인력 배치 기준 을 재정비하고, 다학제 팀의료 상호 협업 중심의 전인적인 돌봄 지원 체 계를 구축하는 것을 제시한다.

This study evaluates the structural stability of a hydrogen shut-off valve used in fuel cell electric vehicles (FCEVs) under extreme operating conditions, including high pressure and cryogenic temperatures. Using a one-way Fluid-Structure Interaction (FSI) analysis based on ANSYS CFX and Static Structural, the study simulates thermal and pressure loads on key components. The results show that the maximum equivalent stress occurs in the rod (361.22 MPa), while safety factors for all components remain above 2.11, confirming adequate structural integrity. In order to secure higher structural stability and reduce the weight of parts, attention should be paid to the selection of materials and improving the shape. The findings provide a valuable basis for improving the design reliability and optimization of hydrogen shut-off valves for future automotive applications. The leak tightness and durability tests of the hydrogen shut-off valve under cryogenic conditions verified its structural integrity, confirming its safety even after more than 5.2 million repeated operations.