전 지구적 탄소중립 및 친환경 에너지 전환 기조에 따라, 본 연구는 발전 설비의 천연가스 연료를 암모니아로 전환하는 공정을 대상으로 정량적 위험성 평가(QRA, Quantitative Risk Assessment)를 수행하였다. HAZOP(Hazard and Operability Study) 및 LOPA(Layer Of Protection Analysis) 기법을 통해 주요 사고 시나리오와 발생 빈도를 도출하였으며, ALOHA 모델링을 통해 피해 영향을 분석하였다. 분석 결과, 암모니아 전환 시 폭발 및 화재 피해 범위는 감소하나, 맹독성 가스 확산으로 인한 대규모 인명 피해 위험이 발생하 는 '리스크 전이(Risk Transfer)' 현상이 확인되었다. F-N Curve를 통한 사회적 위험성 평가 결과, 통제 전 암모니아 누출 사고는 영국 HSE(Health and Safety Executive) 기준 '허용 불가(Unacceptable)' 영역에 위치하였다. 이에 독성 가스 감지기(TGD, Toxic Gas Detector), 긴급차단밸브(SDV, Shutdown Valve), 스크러버 등 다중 독립방호계층(IPLs)을 적용하여 사고 발생 빈도를 낮추고 최종적으로 허용 가능한 위험 수준(ALARP, As Low As Reasonably Practicable)을 달성하였다. 본 연구는 암모니아 발전 설비의 안전장치 확보 및 비상대응체계 구축을 위한 핵심 기초자료를 제공하며, 나아가 지역사회 인명 보호와 기업의 선제적 안전보건 관리체계 확립을 아우르는 지속가능한 ESG 경영 실현에 기여하 고자 한다.

Constructing an efficient electron coupling path is essential for enhancing photocatalytic hydrogen evolution. Here, guided by theoretical design and experimental validation, a Graphdiyne/CoBOx (GDY/CB) ohmic junction catalyst was developed, enabling highly efficient and directional transfer of photogenerated carriers. Density functional theory (DFT) calculations reveal that interfacial bonding between GDY and CoBOx induces strong electronic coupling, suppresses electron backflow, and promotes charge delocalization. Microstructural analyses (SEM/TEM) confirm that the 2D layered GDY framework intimately contacts CoBOx nanosheets, forming a “high-speed channel” for electron migration. In situ XPS under illumination directly captures the photoinduced electron transfer from CoBOx to GDY, evidencing the establishment of a unidirectional transfer pathway. Photoelectrochemical tests, together with the above characterizations, indicate that interfacial coupling markedly enhances hydrogen evolution by reducing transport resistance and optimizing surface kinetics. The optimized GDY/CB-30% exhibits a hydrogen evolution rate of 9.91 mmol·g−1·h−1, 7.56 times higher than pristine GDY and superior to most non-noble-metal photocatalysts. This work highlights carbon-based ohmic junctions as a strategy to overcome bandgap limitations through engineered electron transport.

This study proposes a statistical modeling framework for estimating the daily number of bus stops at highway transfer facilities (ex-HUBs) where demand information is often uncertain during the early planning stages. Accurate estimation of the daily number of bus stops is critical for efficient design and operation; however, reliable demand data are rarely available in the initial planning phase. Using pooled data from 16 facilities, a direct demand estimation approach was implemented, based on facility characteristics, transportation connectivity, highway traffic conditions, and socioeconomic factors. Log-linear model (LLM) and negative binomial model (NBM) were developed to capture the count data characteristics. Ensemble models using arithmetic and weighted means were also constructed to improve predictive reliability. The analysis revealed that the arithmetic mean ensemble of NBM and LLM produced the most accurate predictions. The daily number of bus stops was significantly influenced by the distance from bus terminals, highway traffic volume, public transportation connectivity, economically active population, and level of urbanization. The framework proposed in this study provides a practical tool for estimating the daily number of bus stops at highway transfer facilities, and can support more reliable feasibility analyses and infrastructure planning under demand uncertainty.

목적: 본 연구는 휠체어 사용자의 이승에 영향을 미치는 촉진 요인과 장벽 요인을 체계적으로 고찰하여, 이승 수행과 관련된 주요 요인을 종합적으로 분석하고자 한다. 방법: 본 연구는 2000년 1월부터 2025년 10월까지 게재된 문헌을 CINAHL, Embase, PubMed, Web of Science를 통해 검색하였다. 검색어는 ‘wheelchair’, ‘transfer’, ‘facilitator’, ‘barrier’의 주요 검색 용어를 포함하여 구성하였다. 검색 결과 총 2,316편의 문헌이 확인되었으며, 선정 및 배제 기준에 따라 최종 23편의 문헌을 분석에 포함하였다. 결과: 분석에 포함된 연구의 대상자는 총 3,854명이었으며, 척수손상이 가장 높은 비중을 차지하였다. 휠체어 유형 중에서는 전동휠체어 사용자가 가장 많았다. 휠체어 이승에 영향을 미치는 요인은 사람-환경-작업(Person- Environment-Occupation) 모델에 따라 개인, 환경, 작업 영역으로 분류하였다. 상지 기능과 심리적 요인, 적절한 환경 조정, 교육⋅훈련 및 보조기기 사용은 이승 수행을 촉진하는 요인으로 확인된 반면, 신체 기능 저하, 불리한 환경 조건, 훈련 및 기술적 지원의 부족은 이승 수행의 주요 장벽 요인으로 나타났다. 결론: 본 연구는 휠체어 이승 수행이 개인의 신체적 특성뿐 아니라 환경적 특성과 작업 요인의 상호작용에 의해 결정됨을 확인하였다. 이러한 결과는 휠체어 사용자의 안전하고 효율적인 이승을 지원하기 위한 중재 전략 수립과 이승 보조기기 설계 및 개발을 위한 기초 자료로 활용될 수 있을 것이다.

To study the influence of mass and heat transfer on the microcrystalline structure and properties of mesophase pitch and resulting carbon fiber properties, mesophase pitches were synthesized via pressurized/N₂-blowing thermal condensation with different stirring rates, with experimental conditions optimized using response surface methodology (RSM). RSM analysis confirmed that mesophase content was highly dependent on stirring rate (p < 0.05), and the influencing factors on the formation of mesophase pitch is ranked as reaction temperature > duration time > stirring rate > reaction pressure. The results demonstrated that a moderate increase in stirring rate enhanced molecular diffusion and heat transfer, improving reaction kinetics and aromatic molecule interactions. This accelerated mesophase sphere growth and coalescence while inducing molecular orientation via shear, ultimately yielding a wide-domain optical texture with 100 vol% mesophase content and an optimal softening point (294 °C). The mesophase pitch produced at 300 rpm (MP-300) exhibited a high aromatic structure content (Har = 73.24 wt%), methylene bridges (HF = 3.21 wt%), and fusible/soluble TI-PS sub-fraction (35.7 wt%). MP-300 also displayed exceptional aromaticity (fa = 0.91) and molecular stacking ((Lc = 5.4674 nm, N = 14.7536). Consequently, the resulting carbon fiber (MPCF-300) achieved optimal mechanical properties, with a tensile modulus of 168 GPa and a tensile strength of 1428 MPa. However, excessive stirring rates were found to disrupt molecular cross-linking and stacking, reducing condensation degree, disordering the orderly arrangement of the mesophase molecules, and ultimately impairing the fiber performance. These findings advance the understanding of mesophase pitch formation and provide critical insights for optimizing liquid-phase carbonization theory.

본 연구는 본사와 해외 자회사 간 지식 격차를 감소시키고 기업 성과를 제고하는 데 기여하는 해 외 경영자의 역량을 분석하고, 이러한 역량의 효과가 국가에 따라 어떻게 달라지는지를 한국과 중 국 기업을 대상으로 비교·분석한다. 본 연구의 목적은 국가별 맥락에서 중요하게 작용하는 해외 경 영자의 역량을 규명함으로써, 본사와 자회사 간 지식 활용을 제고하고 실질적인 성과 개선 방안을 도출하는 데 있다. 선행연구 분석을 통해 해외 경영자의 핵심 역량을 의사소통 역량, 학습 역량, 문화적 개방성의 세 가지로 도출하였다. 의사소통 역량은 본사와 자회사 간 공동 비전 공유와 상호 이해를 촉진함으로 써 지식 격차 감소에 핵심적인 역할을 하며, 학습 역량은 필요한 지식을 선별·흡수·활용하는 과정을 통해 정보 비대칭을 완화하고 성과 향상에 기여한다. 문화적 개방성은 구성원 간 신뢰 형성과 태도 에 영향을 미쳐 지식 이전의 효율성을 높이는 역할을 수행한다. 한국과 중국에 진출한 다국적기업을 대상으로 한 비교 분석 결과, 한국에서는 세 가지 역량 모두 지식 격차 감소에 기여하였으나, 기업 성과에는 의사소통 역량과 학습 역량만이 직접적인 영향을 미치고 문화적 개방성은 간접적으로 작용하였다. 반면 중국에서는 의사소통 역량과 학습 역량이 지 식 격차 감소에 유의미한 영향을 미쳤으며, 세 가지 역량 모두 기업 성과에 긍정적인 영향을 보였 다. 또한 의사소통 및 학습 역량의 효과와 이들을 통한 간접 효과는 중국에서 더 강하게 나타난 반 면, 지식 격차 감소가 기업 성과로 이어지는 효과는 한국에서 더 크게 나타났다. 이러한 결과는 해외 경영자의 기능적·인지적 역량과 태도적 역량의 중요성이 국가의 제도적·문화 적 맥락에 따라 상이하게 작동함을 보여주며, 지식 이전과 성과 창출의 메커니즘이 국가 환경에 의 해 구조화된다는 점을 시사한다. 본 연구는 국가별로 적합한 해외 경영자 역량에 대한 이해를 제고 함으로써, 효과적인 역지식이전과 기업 성과 향상을 위한 실무적 시사점을 제공한다.

Anomaly detection is crucial for ensuring the reliability and safety of mechanical systems across industries such as power generation, manufacturing, and transportation. In these mechanical systems, data is usually collected in time-series form using sensors such like vibration, current or sound for anomaly detection. Time-series anomaly detection methods often face limitations due to insufficient training data and poor generalization across complex operating conditions and varying loads. To address these challenges, this study proposes a transfer learning-based anomaly detection model, leveraging pre-trained knowledge to deliver robust performance and adaptability in data-scarce scenarios and diverse industrial environments. To this end, time-series signals are transformed into spectrograms through Short-Time Fourier Transform(STFT), followed by feature extraction through a Convolutional Autoencoder to obtain low-dimensional latent features. These features are used to detect anomalies using classification such as Random Forest and eXtreme Gradient Boosting. Building on this approach, this research validates the model's performance through migration tasks using the Case Western Reserve University(CWRU) Bearings dataset. Furthermore, to show cross-condition generalization, the proposed model was validated on the Hanoi University of Science and Technology(HUST), Sumair–Umar Bearing Fault(SUBF) dataset v2.0, and a dataset collected using microphone sensor in motor dynamo tests. Consequently, unlike other studies limited by specific operating conditions, the proposed model exhibits strong generalization performance across benchmark datasets. Experimental results highlight the effectiveness of combining STFT, CAE, and tree-based classifiers in addressing data scarcity and enhancing generalization, making it highly suitable for real-world industrial applications. Future work will focus on noise-robust techniques and broader fault types to further improve performance.

This study established a method for the simultaneous quantitative analysis of 84 odorous compounds by determining proton transfer reaction rate constants, fragmented ion patterns, and product ion yield ratios through experiments on 33 target compounds and by incorporating previously reported data. In this research, a protontransfer- reaction time-of-flight mass spectrometer (PTR-ToF-MS), a real-time analytical instrument, was employed to quantitatively analyze odorants in process streams and final outlet gases from two wastewater consignment treatment facilities (Facility A and Facility B). The expected odor intensity (EOI) estimation method was further applied to identify the primary odor contributors. Among the final outlet gases, the top five odorcausing substances in Facility A were n-pentanal, acetaldehyde, methylmercaptan, n-hexanol, and n-butanal, while the top five odor-causing substances in Facility B were n-decanal, n-nonanal, acetaldehyde, n-butanal, and n-propanol. The cumulative odor contribution rates of these top five odorants were 94.7% and 91.9% for Facilities A and B, respectively. Although PTR-ToF-MS has inherent limitations in distinguishing isomers and isobars, their individual quantification was achieved through complementary identification and separation by TD-GC-MS. This study provides a basis for simplifying quality control in odor analysis compared with conventional trace-level odor testing methods and proposes a more scientific and effective approach for addressing odor problems.

본 연구에서는 용융염 원자로(MSR)의 열 전달 성능을 최적화하기 위한 수학적 모델을 제안하였다. MSRE 설계 개념을 기반 으로 한 제시된 모델을 통해 차폐 구조물에서의 열 손실을 계산하고, 다양한 변수들이 표면 온도 및 전체 열 성능에 미치는 영향을 평가하였다. SPROULE WR-1200과 같은 칼슘 실리케이트 기반의 단열재를 사용하였으며, 스틸볼 영역은 스틸볼과 물이 채워져 있고, 단열재와 스틸볼 영역 간격(Gap)이 있다고 가정하였다. 분석 결과, 단열재 두께, 간격 크기, 스틸볼 영역의 두께와 같은 변수들이 열 손실 및 표면 온도에 영향을 미친다는 점을 확인할 수 있었다. 특히, 단열재 두께 최적화를 통해 차폐 구조물의 열 효율성과 안전성을 크게 향상시킬 수 있음을 보여주었다. 본 연구는 차세대 원자로 시스템의 개발을 위한 차폐 구조물의 개념설계에 필요한 기초 자료를 제공한다.

The combination of copper and cobalt in the mixed metal oxides phase attracted considerable interest owing to their distinct characteristics and wide-ranging applications across various domains. In this study, we adopt a facile co-precipitation approach to prepare the hollow carbon spheres (HCSs) embedded with CuCo2O4 nanoparticles to enhance the catalytic activity. HCSs are prepared using a hydrothermal template method followed by the removal of the silica template. The resulting CuCo2O4 and HCSs are characterized by using X-ray diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, and Thermo-Gravimetric Analysis to ensure structural integrity and composition. Then, the CuCo2O4 nanoparticle is doped on the porous structure of HCSs using a surface loading method and used as a catalyst for the transfer hydrogenation of acetophenone. The scope is extended using various substrates without a hydrogen source. This nano-catalytic system shows better yields in mild reaction conditions. There was no leaching of the material into the reaction system even after five cycles, thus confirmed by ICP-MS.

In this study, the heat transfer characteristics of a liquid hydrogen (LH2) tank with multilayer insulation (MLI) were numerically investigated. The temperature distribution inside the LH2 tank and within the MLI, as well as the temperature variation according to positional changes, heat transfer rate, and boil-off rate (BOR), were compared and analyzed. The results showed a distinct stepwise temperature drop in Case 4 with 20 MLI layers and Case 8 with 40 MLI layers, where the insulation thickness was greatest. Under the same number of layers, the temperature gradient became more gradual as the MLI thickness increased. In addition, the temperature variation in the tank head region indicated that increasing the number of MLI radiation layers reduced the radiative heat flux, resulting in a gentler temperature variation and a longer temperature drop range. Furthermore, the analysis of heat transfer and BOR showed that both rates decreased under the condition with the greatest MLI thickness and number of layers, demonstrating the best insulation performance. In particular, under the same 40-layer condition, the BOR value of Case 8 was more than three times lower than that of Case 5, indicating a significant improvement in thermal insulation efficiency.

This study investigates the thermal behavior of H7 halogen headlamps through Computational Fluid Dynamics(CFD) analysis and experimental validation. Headlamp geometries were reconstructed via reverse engineering, and simulations incorporated conduction, convection, and radiation effects using the Discrete Ordinate (DO) model. Experiments were conducted using thermocouples and infrared thermography to validate the numerical predictions. The results showed good agreement, with average discrepancies of 3–5% confirming the reliability of the simulation framework. These results demonstrate that current thermo-fluid simulation can accurately capture complex thermal transport phenomena in headlamp assemblies. The proposed methodology is extendable to LED headlamps, providing a practical tool for aftermarket product design, replacement part evaluation, and optimization of next-generation automotive lighting systems.

This study investigates the flow resistance and heat transfer characteristics of a fin-and-tube heat exchanger, applied to a water-cooled thermal management system designed for a cabinet-mounted high-performance computer operating aboard naval vessels. The analysis was conducted through both experimental and numerical approaches, focusing on the evaluation of heat transfer performance (j factor) and flow resistance (f factor) under varying air flow rates, while maintaining a fixed fin geometry and arrangement. Particular emphasis was placed on assessing the variation of the j factor along the total length of the heat exchanger to understand the impact of exchanger length on thermal performance. In the numerical analysis, instead of modeling the entire heat exchanger, a representative repeated unit composed of a single fin and twelve connected tubes was simulated. The outlet temperature from each tube segment was sequentially used as the inlet condition for the subsequent segment. This methodology significantly enhances computational efficiency while providing reliable predictions of progressive thermal characteristics along the flow path.

Graphene, mechanically exfoliated as a single-atom-thick two-dimensional (2D) material, is renowned for its exceptional carrier mobility and mechanical strength, making it a highly promising material for a wide range of applications; however, following the synthesis of large-area, high-quality graphene, quality degradation, such as tearing, frequently occurs during the transfer process. Currently, chemical vapor deposition (CVD) enables reliable synthesis of large-area graphene, and both wet and dry transfer methods are widely employed to transfer graphene onto various substrates. This study focuses on the wet transfer method to improve transfer efficiency by optimizing the interfacial adhesion among graphene, the polymethyl methacrylate (PMMA) support layer, and the target substrate. To enhance the efficiency of the wet transfer process, the PMMA concentration and ultraviolet ozone (UVO) treatment time were systematically optimized. As a result, a transfer yield of up to 97.16 % was achieved under optimized conditions consisting of 6 % PMMA concentration and 15 min of UVO exposure. This research contributes to the development of highly efficient graphene transfer techniques, which are crucial for reducing production costs and processing time in a wide range of advanced applications such as electronics, energy storage, biomedical devices, environmental monitoring, and materials science.

본 연구는 고향사랑기부제가 어떤 제도적 맥락에서 도입되었으며 그 과정에서 드러난 특징과 한계 무엇인가를 분석하기 위해 정책확산과 정 책이전 이론을 활용하는데 목적이 있다. 연구 방법으로는 문헌 검토와 비교 사례분석을 병행하였으며 일본의 제도와 한국의 고향사랑기부제를 법적 근거, 제도 설계, 운영 체계 측면에서 대조하고, 관련 이론의 판정 기준을 사례에 적용하였다. 분석 결과, 첫째, 한국의 고향사랑기부제는 일본 모델을 참조하면서도 국내 재정·행정 환경에 맞게 조정된 혼합적 정책이전의 특징을 보였다. 둘째, 제도 도입 과정은 점진적 확산이 아니 라 중앙정부 주도의 전국적 동시 시행이라는 하향식 확산 경로를 보여 주었다. 셋째, 세제 혜택의 상대적 부족, 법인 기부 불허, 기부금 편중 우려 등은 제도의 효과를 제약하는 요인으로 드러났다. 분석 결과를 토 대로 연구는 첫째, 세제 인센티브 강화, 둘째, 법인 기부 허용을 통한 재 원 다변화, 셋째, 지역 간 불균형 완화를 위한 보정 장치 도입, 넷째, 성 과 중심의 평가 및 환류 체계 구축이 필요하다는 정책적 제언을 제시하 였다. 나아가 본 연구는 고향사랑기부제가 단순한 제도 수용을 넘어 정 책확산과 정책이전이 복합적으로 작동한 사례임을 확인함으로써 지방재 정 확충과 지역균형발전 논의에 의미 있는 시사점을 제공한다.