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.

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.

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.

In this study, static and dynamic analysis verification was performed to apply the fuel cell system to the E-PTO of the Wire aerial vehicle. First, structural analysis was performed to improve the weak points that occurred. Next, vibration analysis was performed on the fuel cell system for which structural safety review was completed according to the wide-band irregular vibration test standard. The analysis results showed that resonance occurred in a specific frequency band and local stress was high, so stiffness reinforcement was performed. After reinforcing the stiffness, stress was reduced through a decrease in transient response characteristics and resonance phenomenon.

Understanding long-term changes in fisheries resources is essential for sustainable ecosystem-based management. This study assessed the quantitative and qualitative changes in Korean coastal fisheries from 1971 to 2024 using an ecological group-based approach. Catch data for approximately 130 species were grouped into 21 ecological groups, and the CMSY model was applied to estimate historical biomass and stock status. Future catch and biomass were projected to 2050 under a conservative scenario assuming reduced resilience. Biodiversity and ecosystem structure were evaluated using mean trophic level (MTL), diversity index (DI), and pelagic/demersal fish ratio (P/D) based on both catch and biomass. Historical total catch and biomass declined substantially while future projections suggest stabilization or modest recovery. The proportion of demersal fish decreased over time and is expected to remain low. MTL showed a gradual downward trend in both catch- and biomass-based indicators. DI showed similar fluctuating trends across both datasets. Although P/D values differed in magnitude, both indicators exhibited a consistent pattern of increase followed by decline, indicating ecosystem structural shifts.

To optimize the electrochemical properties of Ni-rich cathode materials, CPAN@SC-NCM811 is prepared via surface modification of single-crystalline LiNi0.8Co0.1Mn0.1O2 cathode material by adding 1, 2 and 3 wt.% of polyacrylonitrile, respectively. Significantly, the results obtained from X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) verify the successful synthesis of CPAN@SC-NCM811 cathode, which exhibits better electrochemical properties compared to SC-NMC811. After thorough milling and calcination of 2 wt.% polyacrylonitrile with SC-NCM811, the initial discharge specific capacity of prepared S2 sample is 197.7 mAh g− 1 and the capacity retention reached 89.2% after 100 cycles at a rate of 1.0 C. Furthermore, the S2 sample exhibits superior rate performance compared to the other three samples, in which these superior electrochemical properties are largely attributed to the optimal ratio of conductive cyclized polyacrylonitrile coatings. Overall, this work offers guidelines for modifying the surface of SC-NCM811 cathode materials for lithium-ion batteries with exceptional cycling and rate performance.

본 연구는 DNVGL-CG-0127 및 통합공통구조규칙(H-CSR)이 적용된 유한요소해석(FEA)을 통해 검증된, 기존 드라이도킹의 지 속 가능한 대안으로서 안벽 부유식 구조 보수의 타당성을 연구하였다. 정수압 하중을 받는 75K 제품 운반선의 전역 및 국소 거동을 시뮬레이션하여, 보수가 필요한 무시할 수 있는 변위 변화(<1%, 12.3mm~12.4mm)와 von-Mises 응력(26.4MPa, 허용 한계값 188MPa의 14%) 에서, 구조적 무결성을 확인했다. 최적화된 보수 설계는 고강도 해양 등급 강재(예: AH36)와 하위 모델링 기법을 활용하여 Saint-Venant 의 원리와 선형 탄성 가정을 준수하면서 기하학적 불연속점의 응력 집중을 해결하였다. 선급 지침을 준수하면 유체역학적 안정성과 하 중 경로 충실도가 보장되어 선박 운항 중단을 최소화할 수 있습니다. 본 연구 결과는 비용 효율적이고 시간 효율적인 유지보수로의 패 러다임 전환을 보여주며, 기존 방식 대비 가동 중단 시간을 최대 30% 단축합니다. 향후 추진 방향에는 동적 하중 하의 피로 분석, AI 기반 최적화, 그리고 실시간 구조 건전성 모니터링을 위한 디지털 트윈 통합이 포함되며, 이는 해양 탈탄소화 및 운영 민첩성 목표 달 성에 부합한다. 본 연구는 노후화된 선박의 성능 개선을 위한 확장 가능한 프레임워크를 제공하며, 계산 정밀도와 지속가능성에 대한 업계의 요구를 충족한다.

선박용 프로펠러는 선박 추진 성능과 연비에 직접적인 영향을 미치는 핵심 부품으로, 제작 과정에서 높은 정밀도가 요구된다. 사형주조는 복잡한 형상의 금속 부품 제작에 널리 사용되는 공정이지만, 주조 과정에서 발생하는 열적 팽창과 냉각 수축은 최종 치수 오 차와 가공 비용 증가를 초래하는 주요 원인이다. 본 연구에서는 사형주조 과정에서 발생하는 열팽창 및 수축 현상을 정밀하게 예측하고, 이를 고려한 최적의 치수 여유 설정을 통해 연마 작업을 최소화하는 설계 방안을 제안하였다. 알루미늄 청동 합금(ALBC3)을 사용한 프로 펠러를 대상으로 열팽창 공식과 유한요소해석(FEM)을 적용하여 블레이드, 허브, 전체 지름 등 각 부위별 변형을 정량적으로 분석하였다. 분석 결과, 블레이드 너비와 두께는 약 1.9%, 허브 직경은 1.5%, 전체 지름은 2.0%의 여유를 두는 것이 적절한 것으로 나타났다. 이러한 최 적 치수 여유를 적용한 결과, 최대 23kg의 재료 절감, 30만 원 이상의 제작 비용 절감, 작업 시간 50~60% 단축 등의 정량적 개선 효과가 확인되었다. 최적 설계를 적용함으로써 추가 연마 작업과 재료 손실을 줄일 수 있으며, 이에 따른 비용 절감 효과도 기대된다. 본 연구 결 과는 선박용 프로펠러 제작 과정의 품질 향상과 생산성 제고에 기여할 수 있을 것으로 판단된다.

This study numerically investigated thermal-structural characteristics of a liquefied hydrogen (LH) storage cylinder with varying inner pressures and surrounding temperatures. A thermal-structure coupled analysis approach was used to predict the thermal-structural characteristics of the LH storage cylinder. For the simulation, the shape of the LH storage cylinder was simplified using SUS 316L and Carbon Fiber Reinforced Plastic (CFRP) materials. As a result, the inner pressure was a crucial factor determining the structural property (i.e., stress and deformation) of the LH storage cylinder. The high pressure led to increased stress and deformation. Additionally, the surrounding temperature affected the stress and deformation of the LH storage cylinder. For example, at a high surrounding temperature, the temperature gradient along the cylinder increased, thereby causing the occurrence of thermal stress. However, this temperature effect on the stress was negligible compared to the effect of inner pressure. The findings of this study will provide meaningful data for improving the structural safety of LH storage systems.

The chip processing system of large scale machine tool, such as planomiller, turning machine, boring machine and CNC machine, has been continuously used in many industrial fields. As the performance of chip processing system is improved, cutting work with high-precision is also required. This study aims to study the characteristics of the edged part of cutter depending on removing the cutter support in cutter assembly. As the results, the damaged spot in edged part of cutter was different whether the cutter support was installed or not. By removing the cutter support, the safety factor of edged part of cutter was decreased about 4.7 times and furthermore there were some advantages in less than 1.7kN of cutting force.

This study examined the relationship between professional learning communities and work engagement among 227 Chinese university teachers, with a focus on emotional intelligence's mediating role. Using structural equation modeling(SEM), the results revealed: 1) Significant positive correlations among professional learning communities, emotional intelligence, and work engagement; 2) Emotional intelligence partially mediated this relationship, as learning communities both directly enhanced work engagement and indirectly improved it by boosting emotional intelligence. The findings suggest universities should implement emotional competence training to strengthen teachers' self-awareness and regulation skills, while simultaneously fostering collaborative professional communities through shared vision-building, peer collaboration, and institutional support. Additionally, adopting flexible promotion systems informed by international best practices could further enhance teaching engagement, professional dedication, and overall work vitality. These evidence-based recommendations provide a comprehensive approach to supporting teacher development through both emotional and organizational interventions.

임파워먼트에 대한 관심이 꾸준히 증가하고 있는 추세 속에 많은 기업의 관리자들이 구조적 임파워먼 트의 긍정적인 측면만을 바라보고 실제 자신들의 기업에 적용하고 있다. 이는 구조적 관점에서 의사결정 의 권한을 하위 부서로 이양하는 것이 불확실한 상황 속에서 혁신적인 결과물을 탐색하는 데 매우 효과적 일 것이라는 가정에서 비롯되었다. 그러나 조직이 처한 환경 속에서 이러한 구조적 임파워먼트가 실제로 효과적일까에 대한 연구는 거의 이루어지지 않고 있으며, 몇몇 연구에서조차 조직이 처한 다양한 상황적 요인들에 대해서는 전혀 고려되지 않고 있다. 그러므로 본 연구는 NK 모델을 통해 조직의 과업 상호의존 성과 부서의 업무역량에 따라 구조적 임파워먼트가 조직의 창의적 성과 탐색에 미치는 영향을 확인하고, 이에 따른 이론적/실무적 시사점을 제공하기 위해 실시하였다. 분석 결과 첫째, 부서 간 과업의 상호의존 성이 매우 높은 상황에서는 부서의 업무역량에 관계없이 구조적 임파워먼트가 창의적 조직 성과 탐색에 부정적으로 작용하였으며, 조직 차원의 의사결정에 대한 개입이 있을 시 성과가 개선되었다. 또한, 부서의 업무역량이 높을수록 일정 수준 이상의 조직의 개입(조직 수준의 의사결정)이 발생했을 때, 다시 창의적 조직 성과 탐색이 낮아짐을 확인하였다. 둘째, 과업의 상호의존성이 낮은 상황에서는 부서의 업무역량이 높을수록 구조적 임파워먼트의 창의적 조직 성과 탐색에 대한 효과성이 높은 것으로 나타났다. 또한, 구조 적 임파워먼트가 낮아질수록 부서의 업무역량에 관계없이 창의적 조직 성과 탐색도 같이 낮아지는 것을 확인하였다. 이러한 결과는 구조적 임파워먼트가 반드시 창의적 조직 성과 탐색에 긍정적인 영향을 미치 는 것이 아니라 조직이 처한 상황적 요인을 확인하여 실행할 필요가 있음을 시사하며, 구조적 임파워먼트 가 긍정적인 효과를 가져오기 위해서는 조직 차원의 의사결정 개입이 필요할 수 있음을 시사한다.

The purpose of this study is to evaluate by experiments and 3-D finite element predictions of strain-hardening cementitious composite(SHCC) structural walls. The specimen of concrete wall used shear reinforcements to satisfy with design shear strength, while the specimen of a SHCC wall used minimum shear reinforcement. The finite element prediction is based on the total strain crack model, and appropriate tensile models were applied according to the material characteristics of concrete and SHCC. The accuracy of the finite element prediction was verified by comparison with experimental results, and the SHCC wall showed superior structural performances in overall load-carrying capacity as well as in reductions of damages caused by crack localizations, even with minimum use of shear reinforcements.

본 연구는 손 재활을 위한 탐색적 고찰의 일환으로, 자수 기반 스트레인 센서를 단층과 복층 구조로 설계하여 각 구조에서의 접촉 면적 변화와 센싱 성능의 차이를 비교⋅분석함으로써 손가락 동작 센싱에 적합한 센서 구조 설계 방향을 제시하고자 하였다. 1차 실험에서는 다양한 스티치 밀도와 층 구성으로 제작된 센서를 3D 프린팅 관절 모형 에 올린 후 1 Hz 주기의 신전–이완 동작을 반복 적용하여, 생성된 신호의 peak-to-peak 전압(mVp-p)을 측정하였다. 수집된 신호는 형상 분석과 비모수 통계 검정을 통해 정량적으로 분석하였다. 2차 실험에서는 1차 실험 결과를 바탕 으로 복층 구조 센서를 선정하고, 접촉 점 수와 스티치 밀도를 기준으로 네 가지 조합의 센서를 장갑 형태로 제작하 였다. 그리고 스마트 장갑을 착용한 피험자의 엄지와 검지에 대해 굽힘–폄 동작을 기준으로, 센싱 신호의 안정성과 품질을 형상적 특성과 정량 지표를 통해 분석하였다. 실험 결과, 1차에서는 복층-고밀도 구조 센서가 단층-저밀도 구조에 비해 유의하게 높은 신호 크기를 나타냈다. 2차 실험에서도 복층-고밀도 구조가 상대적으로 더 우수한 신호 품질을 보이는 것으로 확인되었다. 결론적으로, 1차 실험에서는 센서의 구조적 설계가 신호 세기에 직접적인 영향을 미친다는 점을 입증하였고, 2차 실험에서는 실제 사용 환경에서도 자수 구조적 변수에 따라 신호 품질이 달라짐을 확인하였다. 이는 자수형 센서 설계 시 구조적 설계 의 중요성을 시사하며, 웨어러블 손 재활 장치 개발에 기초 자료로 활용될 수 있을 것이다.

LiFePO4/C has been successfully synthesized using surfactant-assisted solid-state reaction method to investigate the effects of non-polar solvents on structural properties and electrochemical performance. Petroleum jelly, oleic acid, and sucrose were used as non-polar solvents, surfactants and carbon sources. The ratio of petroleum jelly and oleic acid were 0.5:1 (LFP A), 1:1 (LFP B), and 2:1 (LFP C). The XRD, FE-SEM, and HR-TEM results show that adding petroleum jelly in LFP C enhances crystallinity and improves the morphology of nanoplates in LiFePO4 material. The EDS and Raman Spectroscopy tests show that the higher addition of petroleum jelly increases carbon percentage and carbon layer defects. The highest Li-ion diffusion coefficient was calculated by LFP C of 4.21 × 10– 15 cm2. s−1. Furthermore, the highest discharge test results at 0.1 C of LFP A, LFP B, and LFP C were 125 mAh.g−1, 103 mAh.g−1, and 144 mAh.g−1, respectively. However, C-rate performance shows that the specific capacity of LFP A, LFP B, and LFP C at 5 C were 74 mAh.g−1, 35 mAh.g−1, and 59 mAh.g−1, respectively. The cyclability test results showed that LFP A capacity retention after testing for 100 cycles was better than LFP C, and the lowest stability was obtained by LFP B. The addition of petroleum jelly improved the performance of LiFePO4/ C but resulted in excess carbon in active material which decreased battery stability and specific capacity at high C-rate. Our results suggest that non-polar solvents can be added to LiFePO4/ C synthesis to improve electrochemical performance but less carbon chains must be chosen.

In the area of carbon-based thin films, graphene/polyimide conductive films display remarkable heat resistance and mechanical properties, making them a valuable resource for utilisation in a multitude of manufacturing and living contexts. Nevertheless, modulating the interfacial structure between graphene and polyimide represents a significant challenge in the pursuit of enhancing the conductivity of the composite films, due to the elevated initial temperature of polyimide pyrolysis (exceeding 600 °C). To develop it, this study found that polyimide could undergo chemical bond breaking and atomic rearrangement at around 500 °C, when subjected to an applied electric field in graphene/polyimide films. A series of characterisations showed that the graphene/polyimide film formed a new interfacial structure under electrothermal treatment, which enhanced the electron transport capacity and increased its conductivity from about 1497.01 s m− 1 to about 2688.17 s m− 1, with an increase of about 79.57%. This study would provide the possibility of modulating the structure of polyimide below the pyrolysis temperature, as well as a feasible idea for transferring the properties of graphene into the polyimide matrix.