Hydrogen embrittlement (HE) remains one of the most critical challenges in ensuring the structural integrity of steels for hydrogen energy infrastructures, including storage and transport systems. Despite decades of research, the underlying mechanism of HE is still not fully understood due to the complexity of hydrogen-microstructure interactions across multiple length scales. Cryogenic Atom Probe Tomography (Cryo-APT) has recently emerged as a unique method of providing near-atomic resolution and compositional sensitivity for hydrogen analysis, thereby enabling direct visualization of hydrogen distribution at defects, interfaces, and precipitates. This review summarizes recent progress in Cryo-APT-based investigations of hydrogen behavior in steels, with a focus on trapping mechanisms, the role of microstructural features, and the synergistic activation of multiple HE mechanisms. Key technical developments, such as cryogenic workflows and isotope tracing, have significantly advanced the reliability of Cryo-APT hydrogen quantification. Case studies on ferritic-martensitic steels, pearlitic steels, and advanced high-strength steels highlight the potential of Cryo-APT to reveal both diffusible and non-diffusible hydrogen trapping. While current limitations include local sampling bias, experimental complexity, and signal interpretation challenges, continuous improvements in methodology and integration with multiscale modeling are expected to establish Cryo-APT as a core approach for elucidating HE mechanisms. This review provides a comprehensive perspective on the current technical state and future directions of Cryo-APT in HE researches.

This study analyzed online food consumption behaviors by segmenting consumers based on their dietary lifestyles using the Consumer Behavior Survey for Food in 2024 of the Korea Rural Economic Institute. Factor analysis and cluster analysis classfied the dietary lifestyles of the respondents into the ‘convenience and experience-seeking group’, ‘low involvement group’, ‘health-seeking group’, and ‘plan-seeking group’. The highest frequency of online food purchases by respondents was ‘once every two weeks’, and the most common reason for purchasing food online was ‘because it is delivered’. The most frequently used channel for online food purchase was ‘online shopping malls’, with price, quality, and overall satisfaction remaining above average. The analysis of perceptions and behavioral patterns revealed that consumers primarily utilized online food services for their convenience and place significant importance on others’ experiences and verified brands. Among the dietary lifestyle groups, the ‘convenience and experience-seeking group’ showed the highest mean scores across most perceptions and behavioral items. These results confirm that online food consumption varied significantly depending on dietary lifestyle groups, highlighting that dietary lifestyle is a crucial factor for market segmentation and the development of targeted marketing strategies.

본 연구는 금융교육의 궁극적인 목표인 합리적인 금융행위 실현 및 금융웰빙 달성을 위하여 금융교육이 금융행위에 영향을 미치는 경로를 실증적으로 분석하고자 하였다. 특히, 금융지 식과 금융태도를 매개변수로 설정하여 금융교육이 금융지식 수준을 높이고, 높은 수준의 금 융지식은 긍정적이고 올바른 금융태도를 형성하며, 그러한 금융태도는 곧 금융행위의 변화 를 유발할 것이라는 판단 하에 연구모형을 설정하고 경로분석을 실시하였다. 연구 결과, 금 융교육 경험은 금융지식에는 직접적인 영향을 미치지 않았지만, 금융태도와 금융행위에는 직접적 영향이 있는 것으로 나타났다. 나아가, 금융교육 경험과 금융행위의 관계에서 금융 태도의 매개효과를 통계적으로 검증하여, 교육이 결국 실천으로 이어지게 되는 중요한 경로 를 확인할 수 있었다. 본 연구를 통해 금융교육이 단순한 지식 전달에 머무르지 않고, 성인 의 정의적 영역인 금융태도를 함양하여 궁극적으로 행동의 긍정적인 변화를 유도할 수 있음 을 밝혀냄으로써 금융교육 효과의 검증과 추후 금융교육 프로그램 개발에서의 시사점을 제 공할 수 있을 것으로 기대한다.

하수 성상의 복잡성과 인구증가 그리고 빠른 도시화에 대응하기 위해 오염원에서 하수를 재이용하는 중수도 시스 템의 중요성이 부각되고 있다. 중수(greywater)는 가정 하수 중 변기를 제외한 세면대, 욕실, 싱크대, 세탁기 등에서 발생하는 하수를 의미한다. 본 연구는 가압식 한외여과(ultrafiltration) 분리막 시스템을 이용하여 중수의 직접 여과 및 주기적 역세척을 포함하는 분리막 여과 공정 수행을 통해 역세수의 성상에 따른 투과도 회복 효과를 분석하였다. 실험 결과, 세제에 일반적으 로 포함된 계면활성제 성분이 막 파울링(fouling) 완화에 지배적으로 기여하였고 계면활성제 부재 시 분리막 투과도는 여과 시작 15 min 만에 초기 투과도 대비 90%가 감소한 것을 확인할 수 있었다. 또한, 기존 연구 결과와 달리 분리막에서 생산되 는 투과수를 역세척수로 사용했을 때 수돗물을 적용하였을 때보다 투과도 회복률이 약 16% 더 높음을 확인할 수 있었다. 특 히, 투과수를 이용한 화학적 강화 역세척(chemical enhanced backwash, CEB)을 수행하였을 때 투과수의 성분과 첨가된 차아 염소산나트륨(NaOCl)의 시너지 효과로 인해 분리막 파울링을 효과적으로 감소시킬 수 있었다.

In the present study, to investigate the seismic behavior of a cabinet under earthquakes, three types of mass blocks (top load, center load, and bottom load) were selected as the cabinet's internal structure, and the vibration characteristics according to the load arrangement were studied. The internal structure simulates the device modules installed inside the cabinet. The cabinet's modal characteristics and response spectrum were evaluated under the three types of loads. Six modes, displacement, and acceleration responses for each load were analyzed. The analysis results showed that mode 1 had the lowest frequency, and that the frequency increased by approximately two times as the mode increased. The change in natural frequency according to load placement was confirmed through modal analysis of the cabinet. The cabinet's displacement and acceleration were greatest in the x-axis and lowest in the y-axis. Displacement and acceleration according to the load distribution at the top, center, and bottom were within a certain range, so the vibration characteristics of the internal structure of the cabinet were limitedly affected.

본 연구는 20·30대 MZ세대의 친환경 행동의도에 영향을 미치는 환경 동기요인을 실증적으로 분석하고, 기후변화 심각성 인식이 이들 동기와 친환경 행동의도 간에 매개효과를 갖는지 실증적으로 분석하는데 목적이 있다. 2024년 국민환경의식조사에 참여한 968명의 청년층을 대상으로, 환경 동기요인(규범적, 쾌락적, 이익, 이타적, 생태적, 이기적 동기)과 기 후변화 심각성인식, 친환경 행동의도 간의 관계를 PROCESS Macro 4.2 를 활용해 분석하였다. 분석 결과는 다음과 같다. 첫째, 규범적 동기가 친환경 행동의도에 가장 큰 영향을 미쳤으며, 쾌락적 동기 역시 유의미 한 영향을 보였다. 둘째, 이익 동기와 이타적 동기는 친환경 행동의도에 직접효과만 있었고, 기후변화 심각성 인식을 통한 간접효과는 없는 것으 로 나타났다. 셋째, 생태적 동기와 이기적 동기는 기후변화 심각성 인식 을 매개로 한 간접효과만 나타났다. 이러한 결과는 MZ세대의 친환경 행 동을 촉진하기 위해 규범적·쾌락적 동기 강화와 기후변화 심각성 인식 제고가 중요함을 시사한다.

이 논문은 소비자 설문조사를 통해 여름철 대표 과일인 수박과 참외의 소비자 구매 행태와 구매 빈도에 영향을 미치는 요인을 분석하여 수박·참외 산업의 지속 가능한 발전 방향을 탐구하고자 하였다. 소비자 구매 행태를 분석하고, 구매 빈도에 영향을 미치는 주요 요인을 규명하기 위해 순위형 로짓 분석을 실시하였다. 연구 결과에 따르면 수박은 맛, 외형이 가격보다 더 중요한 요소로 나타나, 고당도 수박 생산, 품종 개선 및 유통 방식 개선의 필요성이 제기되었다. 참외는 맛, 신선도, 외형이 구매시 중요한 요소로 분석되었으며, 고령층 소비자에 비해 젊은층 선호도가 상대적으로 낮아 참외 시장 확대를 위해서는 다양한 소비 계층이 관심을 가질 수 있는 차별화된 판매 전략이 필요하다는 점을 시사하였다.

The purpose of this study is to investigate the dynamic behavior of the internal cabinet of a nuclear power plant due to an earthquake and the characteristics of cabinet vibration reduction by TMD(tuned mass damper). For this purpose, the experimental device was constructed and numerical analysis was performed. The experimental device for the dynamic behavior of the cabinet consists of a cabinet, sliding base, mount, actuator, exciter, and measuring system, and the frequency response function of the cabinet was obtained. In addition, the time history of the cabinet was analyzed for acceleration and displacement through TMD design and cabinet 3D modeling. The natural frequency and response of the cabinet were lowered by approximately 26% due to the structural rigidity of the cabinet under the conditions of door opening and sliding base strong excitation. The acceleration and displacement characteristics of the cabinet varied depending on the TMD mass, and the cabinet vibration reduction effect was the best when the TMD mass was 60kg. The reduction in acceleration and displacement of the cabinet was approximately 12.1–16.2% and 10.1–19.1%, respectively.

고밀도폴리에틸렌(HDPE)은 소형선박용 차세대 선체 재료로 주목받고 있으나 재료의 열변형온도가 하절기 선박 운용 온도와 유사하여 건조 및 운용 과정에서 선체의 구조적 거동에 대한 고려가 필요하다. 본 연구에서는 모의설계한 HDPE 어선을 대상으로 연중 태 양복사가 가장 강하고 기관실 내기 온도가 최고에 도달하는 혹서기 운용 조건을 모사한 열전달 해석을 수행하였다. 특히, 최고 고온환경 이 조성되는 기관실 구획의 내부 구조부재에 두 가지 방열재 시공 조건을 적용하여 선체 구조의 온도 응답 및 열변형 거동을 평가하였다. 그 결과, 방열재 시공은 HDPE 선체 온도의 상승을 억제하는 효과가 있으나 그 수준은 제한적임을 확인하였다. 따라서 여름철 운항에서 선체의 구조적 안전성을 확보하기 위해서는 기관실 내기 온도 저하 등 능동적 열관리 방안을 병행할 필요가 있다.

The use of aluminum-based hybrid metal matrix composite (HMMC) materials, especially in engine components like pistons, is intended to improve wear resistance and overall performance. Crucial tribological indicators, such as wear and friction coefficients, underscore the significance of these materials. However, present aluminum alloys have limited wear because of clustered reinforced particles and relatively high coefficients of thermal expansion (CTE), resulting in inadequate anti-seizure properties during dry sliding conditions. This research introduces a novel “Hybrid Metal Matrix Composite of Al7068 Reinforced with Fly Ash-SiC-Al2O3”. Al7068 is employed for its superior strength-to-weight ratio and specific modulus, which is ideal for components exposed to cyclic loads and varying temperatures. The integration of fly Ash (FA), silicon carbide (SiC), and alumina (Al2O3) as reinforcements enhances wear resistance, diminishes particle clustering, improves stiffness, mitigates CTE discrepancies, and fortifies the composite against strain and corrosion, thereby enhancing its overall performance. The Stir-casting method was used with optimized reinforcement percentages (10 % total), and comprehensive evaluations through wear tests and mechanical property analyses determined the composite's optimal composition. The proposed HMMC variant with the most suitable reinforcement percentage exhibited enhanced engine piston functionality, reduced wear, low deformation of 0.20 mm, and a comparatively higher ultimate tensile strength of 190 megapascals (Mpa).

일체식 교대 교량 공법은 1930년대부터 미국과 캐나다에서 적용되었으나, 국내에서는 공용 기간이 짧아 설계, 시공 및 유지관리 경 험이 부족하다. 또한, 장기 거동에 대한 추적 데이터가 부족해 설계 시 예측한 구조 거동의 안정성 검증이 필요하다. 본 연구는 국내 공 용 중인 일체식 교대 교량을 대상으로 장기 계측을 수행하고, 선행 연구에서 제안된 수치 해석 모델을 적용해 구조 안정성과 모델의 적용성을 검증하였다. 계절적 온도 변화에 따른 변위 값의 크기와 변화 형상을 정성적으로 평가하고, 실측과 수치 해석 변위 값을 t 검 정으로 비교해 정량적 검증을 수행하였다. 분석 결과, 대상 교량들은 예측 값과 실측 값이 큰 오차 없이 안정적인 구조 거동을 보였다. 일부 교량에서는 교대 밀림으로 인한 신축 이음 축소와 교대 벽체 및 거더부 협착이 관찰되었다. 모델링 정확도를 높이기 위해 지반- 교대 스프링 강성과 교좌 전단 강성을 설계 값보다 높게 반영하는 것이 필요하다.

This study examined the intake status and the factors affecting intake of functional foods using the data from Consumer Behavior Survey for Food by the Korea Rural Economic Institute. Among the total respondents, 80.4% took functional foods, and the number of respondents who took two types of functional foods was the highest. The main reason for taking functional foods was to prevent disease, and the main places of purchase of functional foods were off-line large supermarkets, on-line shopping malls, and pharmacies. Compared to a year ago, the percentage of increase in functional food purchases this year was higher than the percentage of decrease. The most common reasons for not taking functional foods were ‘not feeling the need’ and ‘not trusting the quality’. As a result of conducting a complex samples logistic regression analysis to identify the factors affecting the intake of functional foods, gender, age, marital status, illness state, alcohol drinking, and convenience-seeking type among dietary lifestyles were significant.

This study examined differences in breakfast habits, mental health, and the prevalence of allergic diseases among 9,549 adolescents from father-headed and mother-headed families, using raw data from the 2017~2019 Korea Youth Risk Behavior Web-Based Survey. Of the total participants, 44.6% came from father-headed families, while 55.4% were from mother-headed families. Single-parent adolescents showed the highest likelihood of eating breakfast every day of the week (24.5%), but they also had a significant tendency to skip breakfast entirely (24.3%). There was no significant difference in breakfast frequency between those from father-headed and mother-headed families. The perception of stress and subjective health status did not differ significantly between adolescents from the two types of families, although subjective health status did show significant differences among boys. Depressive experiences were notably higher in adolescents from mother-headed families (33.0%) compared to those from father-headed families (30.8%). Additionally, the prevalence of atopic dermatitis and allergic rhinitis was significantly greater in adolescents from mother-headed families (24.2% and 32.1%, respectively) than in those from father-headed families (21.1% and 26.5%, respectively). These results indicate the need for tailored nutrition and health guidance programs for adolescents from single-parent families to support the role of the absent parent.

Background: The increasing demand for real-time professional fitness coaching has led to a need for accurate exercise posture recognition using artificial intelligence. Objectives: To compare the performance of Feedforward Neural Network (FNN) and Stacked Long Short-Term Memory (LSTM) models in classifying fitness posture images using detailed joint coordinate labeling. Design: Comparative analysis of machine learning models using a labeled dataset of fitness posture images. Methods: A dataset from AI-hub containing images and data of 41 exercises was used. Five exercises were selected and processed using a custom program. Data was converted from JSON to CSV format, augmented with joint condition information, and analyzed using Google Colab. Results: The best FNN model achieved a training error of 1.21% and test error of 9.08%. The Stacked LSTM model demonstrated superior performance with a training error of 1.05% and test error of 6.09%. Conclusion: Both FNN and Stacked LSTM models effectively classified sequential fitness images, with Stacked LSTM showing superior performance. This indicates the potential of Stacked LSTM models for accurate fitness posture classification in real-time coaching scenarios.

Battery electrodes, essential for energy storage, possess pores that heavily influence their mechanical properties based on the level of porosity and the nature of the pores. The irregularities in pore shape, size, and distribution complicate the accurate determination of these properties. While stress-strain measurements can shed light on a material’s mechanical behavior and predict compression limits, the complex structure of the pores poses significant challenges for accurate measurements. In this research, we introduce a simulation-driven approach to derive stress-strain data that considers porosity. By calculating relative density and the rate of volume change under compression based on porosity, and applying pressure, we conducted a parametric study to identify the elastic modulus (E) in relation to the rate of volume change. This information was utilized within a material modeling equation, generating stress-strain (S-S) curves that were further analyzed to replicate the compression behavior of the electrode material. The outcomes of this study are expected to improve the prediction accuracy of mechanical properties for porous electrode materials, potentially enhancing battery performance and refining manufacturing processes.

This study investigated the behavior and environmental impact of expanded polystyrene (EPS) in a simulated marine environment, focusing on the effects of UV exposure. Through a series of controlled experiments, it was found that UV-induced weathering increased the formation of smaller EPS degradation products, leading to higher concentrations of dissolved organic carbon (DOC) in the seawater. Additionally, it was suggested that the assembly behavior of dissolved organic matter (DOM) contributed to the reduction of DOC levels over time. The EPS layer exhibited slightly higher DOC concentrations compared to the seawater, likely due to hydrophobic interactions that retained degradation products near the EPS. Analysis of the soil layer revealed that EPS particles and degradation products settled or adsorbed more extensively under UV conditions, indicating a greater risk of sediment contamination. Soil layer elution experiments further confirmed that EPS particles and their degradation products could migrate through soil pores, posing a potential contamination risk to other environments. UV exposure resulted in a twentyfold increase in DOC release from EPS compared to dark conditions. These findings highlight the persistent pollution potential of EPS in marine environments, especially under UV exposure, and emphasize the need for effective EPS waste management and further research into its environmental impacts.

This study analyzed the status of agrifood consumer competencies and the factors influencing them to provide useful information to improve the quality of life by strengthening the agrifood consumer competencies. The raw data of the 2022 Consumer Behavior Survey for Food collected by the Korea Rural Economic Research Institute were used. The data from 3,321 responses were used for the final analysis. Among the competencies, the average score of the cognitive and practical competencies were 3.543 and 3.459 points, respectively. In addition, the average scores of the specific areas within cognitive competency were 3.587 points for dietary competency, 3.557 points for civic competency, and 3.489 points for purchasing competency. Within practical competency, the average scores of the specific areas were 3.569 points for dietary competency, 3.422 points for civic competency, and 3.392 points for purchasing competency. Gender, age, monthly household income, marital status, administrative district, interest in health, and interest in food safety issues were the significant factors affecting the specific areas within cognitive competency. On the other hand, gender, age, educational level, monthly household income, marital status, administrative district, interest in food safety issues, and each of the areas within cognitive competency had a significant impact on the specific areas of practical competency.