This study aimed to investigate the vascular flora of Baekunsan Mountain (255.5 m), located on Yeongjongdo Island in Jung-gu, Incheon Metropolitan City, through 14 field surveys conducted between March 2021 and April 2024, along with a re-examination of voucher specimens collected in a previous study. As a result, a total of 478 taxa, comprising 430 species, nine subspecies, and 39 varieties across 289 genera and 96 families, were identified in the area. Of these, 33 taxa were newly confirmed through specimen re-identification. Three endemic taxa native to the Korean Peninsula were documented. Additionally, three taxa listed on the IUCN red list were found; one Near Threatened (NT) and two Least Concern (LC). The survey also recorded 37 floristic target plants, including 10 taxa of grade III, six taxa of grade II, and 21 taxa of grade I. A total of 49 alien plants were identified, with a naturalization rate of 10.3% and an urbanization index of 12.5%, both showing an increase compared to past surveys. This rise is likely due to the continued development and anthropogenic disturbances in the surrounding areas. Six taxa of ecosystem-disturbing plants were found including four newly observed species, such as Ambrosia artemisiifolia, Ambrosia trifida, Aster pilosus, and Lactuca scariola, in addition to previously recorded species, such as Humulus japonicus and Rumex acetosella. Given that the Yeongjongdo Island is a geographically isolated island with limited habitat space and is subject to ongoing development plans, the area is considered highly vulnerable to environmental change. Therefore, the findings of this study are expected to serve as foundational data for monitoring biodiversity trends and formulating strategies for conservation and management of native plant species in Baekunsan Mountain and its surroundings.

Early warnings have been developed to provide rapid earthquake information, allowing people to prepare as much time as possible. However, since it takes several seconds for an earthquake warning to be issued, the blind zone is inevitable. To reduce the blind zone, information from a single observatory is used to operate an on-site earthquake warning. However, false and missed alarms are still high, requiring continued research and validation. This study predicted Peak Ground Acceleration (PGA) using the characteristic data to reduce false and missed alarms in on-site earthquake warnings. A machine learning prediction model was created using the initial P-wave parameters developed from the characteristic data to achieve this. Then, the model was used to predict the maximum ground acceleration in the southeastern region of the Korean Peninsula. The expected results for six target earthquakes were confirmed to have a standard deviation within 0.3 compared to the observed PGA and the values within ±2 sigma. This method is expected to help develop an on-site early warning system for earthquakes.

In the evolving global food industry, international certifications have become essential for seafood export companies to ensure product safety, quality, and sustainability, as well as to meet consumer demands and regulatory standards. This study analyzes the decision-making factors influencing the acquisition and maintenance of international certifications among Korean seafood export companies, using decision tree analysis. The research surveyed 134 seafood export companies, focusing on six key factors: corporate characteristics, environmental factors, input factors, organizational structure, company capabilities, and external relationships. The decision tree analysis revealed that among corporate characteristics, the size of sales revenue, number of employees, and proportion of exports were found to play significant roles. For environmental factors, specific demands from overseas buyers, shifting consumer preferences, and compliance with global standards were identified as having a major impact. Regarding input factors, certification costs, validity periods, and investments in processing facilities were revealed to be critical variables. Organizational factors such as managerial support and dedicated personnel, capability factors like inter-departmental collaboration and processing system capacity, and relationship factors including partnerships with certification and export support agencies were also critical in the certification process. This study identified various factors influencing the decision-making process for acquiring and maintaining international certifications among Korean seafood export companies and analyzed the importance of detailed variables for the first time. Additionally, it provides practical and policy-oriented implications to promote the adoption of international certifications as part of efforts to enhance the global competitiveness of Korean seafood. Furthermore, this study contributes to the academic understanding of the decision-making process related to international certifications in seafood export companies.

In various machines used in industrial sites and transportation equipment, fastening structures of bolts and nuts are widely employed. However, conventional Steel sockets, classified as non-explosion-proof materials, have a high likelihood of generating sparks due to friction with components, which can lead to explosions or large-scale fires. To address this issue, this study developed a lightweight explosion-protection socket using AL-7075-T6 aluminum alloy, which is known for its excellent explosion-proof properties. However, due to the inherent characteristics of aluminum, it has lower rigidity compared to Steel, requiring the use of more expensive alloy materials. Therefore, our research team utilized Finite Element Analysis (FEA) and Multi-Objective Genetic Algorithm (MOGA) to optimize the mass and safety factor of the socket, proposing a design that simultaneously achieves both weight reduction and structural stability. The socket developed in this study is approximately 30% lighter than traditional Steel-based sockets while maintaining a safety factor of 1.2 or higher, significantly enhancing operational safety in explosive environments. This research sets a new standard in the design and manufacturing process of explosion-proof sockets and is expected to contribute to the optimization of various explosion-proof equipment in the future.

본 연구는 합성 아질산염 대체 천연보존료로 개발하고자 천연물 유래 복합추출물(NP-NAP, NP-NAMR)의 성분 특성 과 소시지에의 적용 시 품질 특성을 규명하였다. NP-NAP 와 NP-NAMR 0.5-1.0% (w/v)는 90.1-100%의 ABTS 라디 칼 저해능과 10 mg/mL에서 각각 811 μM 및 770 μM trolox 상당의 FRAP 활성을 보였다. NP-NAP와 NP-NAMR은 S. aureus와 L. monocytogenes, E. coli 및 S. Typhimurium에 대 해 0.1% (w/v)에서 99.99-100%의 감소율을 보였고 C. perfringens에 대해 1%와 2% (w/v)에서 각각 89.0-91.4%와 84.7-100% 이상의 감소율을 보였다. 천연 복합추출물 첨가 소시지 시제품의 냉장 중 품질 특성에서 4주 차 pH (6.43- 6.57)와 NP-NAMR 첨가 시 높은 a 값(23.54% 및 28.81)을 확인하였다. Springiness와 cohesiveness는 NP-NAP 1%가 높 았으나 다른 모든 시험구는 양성 대조구와 유의적 차이가 없었다(P<0.05). 냉장 중 평균 MDA (0.87-1.183 μM)는 양 성 대조구(0.93-0.96 μM)와 유사하였으며(P<0.05) 총 증가 균수(log CFU)는 1% 첨가(1.10-1.32) 시 nitrite pickling salt (NPS) 0.08% (1.31)과 유사하였고 2% 첨가 시(0.17-0.49)는 commercial product from Spain (CPS) 1% (0.53)보다 적었 다. 종합적 기호도는 NP-NAMR 2% 제외한 모든 시험구는 통계적 유의차가 없었다. 이상의 결과, 과채 추출물 유래 NP-NAP와 NP-NAMR은 항산화, 항균 활성과 안정적인 적 색도와 함께 식약처 고시 소시지류의 기준 및 규격을 만족 하여 합성 아질산염과 시판 수입품을 대체하는, 유효한 소 재가 될 수 있을 것으로 사료된다.

본 연구에서는 열유도상분리법으로 제조한 polyvinylidene fluoride (PVDF) 중공사막의 오염성과 화학적 세척에 대한 실험을 진행하였다. 오염수는 소 혈청 단백질(bovine serum albumin, BSA)과 카올린(kaolin)을 이용해 제조하였으며, 차아 염소산나트륨(NaOCl), 구연산(citric acid), 황산(H2SO4)으로 화학적 세척을 진행한 후 뒤 표면 전하 분석기, 주사전자현미경 (scanning electron microscope, SEM) 그리고 에너지 분산 X선 분광법(energy dispersive X-ray spectroscopy, EDX)을 통해 세 척 효율을 평가하였다. PVDF 분리막은 높은 내화학성과 열적 안정성을 가지는 분리막으로 화학적 세척을 진행한 결과 가장 좋은 효율은 차아염소산나트륨으로 세척한 것으로 그 결과 투과도는 793.2 L/(m2.h.bar)로 초기 투과량인 945.3 L/(m2.h.bar) 값과 비교하였을 때 약 84% 회복률을 보여주었다. 이는 수처리 공정에서의 막 오염 방지 및 세척의 중요성을 제시한다.

고체전해질은 높은 에너지 밀도와 안전성을 갖춘 차세대 리튬이온전지에 꼭 필요한 핵심 요소다. 이러한 고체전 해질의 제작을 위해서 기존 고체전해질의 낮은 이온전도도와 높은 계면저항 문제를 해결해야 한다. 본 연구에서는 강화된 이 온 전도성과 계면 안정성을 지닌 PVDF-HFP 고분자에 분산된 Li7La3Zr2O12 (LLZO) 나노와이어 복합체를 기반으로 하는 새 로운 전해질(PVDF-HFP/LLZO/SN, PHLS membrane)을 제안한다. PHLS에 용매 열압착(Sovlent heat press, SHP)을 통해 계 면 저항과 내부 공극이 감소된 PHLS-(SHP)는 30°C에서 2.06 × 10-4 S/cm의 높은 이온 전도도, 4.5 V (vs. Li/Li+)의 넓은 전 기화학적 전위 창, 리튬 금속과 전해질 사이의 안정된 계면 안정성을 나타냈다. 0.2 mA/cm2에서 수행된 Li 대칭 셀을 사용한 전기화학적 테스트에서 150 시간 이상 안정성을 유지하는 것으로 확인되었으며, 이는 당사의 복합 기반 고체 전해질을 활용 하여 전기화학적 성능이 향상되었음을 시사한다.

This study aimed to develop a systematic process for identifying components that need to be changed to reduce the Head Injury Criterion (HIC) during pedestrian headform tests. Through simulation and analysis, it was confirmed that the hood, hinge, hinge plate, cowl, fender, and fender bracket significantly influence HIC15. The study identified the specific impact of each component on HIC15, allowing for targeted improvements. The proposed process demonstrated superior performance compared to single-component optimization, yielding more significant reductions in HIC15. Multiple vehicle models were tested, confirming the process's effectiveness in consistently lowering HIC15 values.

Hot section components of gas turbines are exposed to a high operating temperature environment. To protect these components, thermal barrier coatings (TBC) are applied to their surfaces. Yttria-stabilized zirconia (YSZ), which is widely used as a TBC material, faces limitations at temperatures above 1200 °C. To mitigate these issues, research has focused on adding lanthanide rare earth oxides and tetravalent oxides to prevent the phase-transformation of the monoclinic phase in zirconia. This study investigated the effects of varying TiO2 content in Nd2O3 and Yb2O3 co-doped YSZ composites. Increasing TiO2 content effectively suppressed formation of the monoclinic phase and increased the thermal degradation resistance compared to YSZ in environments over 1200 °C. These findings will aid in developing more thermally stable and efficient TBC materials for application in high-temperature environments.

Mo-ODS alloys have excellent mechanical properties, including an improved recrystallization temperature, greater strength due to dispersed oxides, and the ability to suppress grain growth at high temperatures. In ODS alloys, the dispersed Y2O3 and added Ti form Y-Ti-O complex oxides, producing finer particles than those in the initial Y2O3. The complex oxides increase high-temperature stability and improve the mechanical properties of the alloy. In particular, the use of TiH2 powder, which is more brittle than conventional Ti, can enable the distribution of finer oxides than is possible with conventional Ti powder during milling. Moreover, dehydrogenation leads to a more refined powder size in the reduction process. This study investigated the refinement of Yi2Ti2O7 in a nano Mo-ODS alloy using TiH2. The alloy compositions were determined to be Mo-0.5Ti-0.5Yi2O3 and Mo-1.0Ti-0.5Yi2Oi2. The nano Mo-ODS alloys were fabricated using Ti and TiH2 to explore the effects of adding different forms of Ti. The sintered specimens were analyzed through X-ray diffraction for phase analysis, and the microstructure of the alloys was analyzed using scanning electron microscopy and transmission electron microscopy. Vickers hardness tests were conducted to determine the effect of the form of Ti added on the mechanical properties, and it was found that using TiHi2 effectively improved the mechanical properties.

탄소중립을 달성하기 위해 이산화탄소를 포집, 활용, 저장하는 CCUS (carbon capture, utilization, and storage) 기 술이 주목받고 있다. 본 연구에서는 광물 탄산화 공정을 통해 이산화탄소를 탄산염으로 고정하고, 이를 전이금속 탄산염 기반 리튬이온배터리 (LIB) 음극재로 적용하였다. CO2를 탄산염으로 고정후, 이를 이용해 FeCO3를 제작하고, rGO와 PVP와 복합 화하여 음극활물질에 적용하였다. rGO는 전기전도도를 높이고 입자의 응집을 방지해 부피 팽창을 완화했으며, PVP는 계면 활성제로서 입자 표면을 안정화하여 구조적 안정성을 강화하였다. FeCO3-PVP-rGO 복합체 기반한 음극재에 대한 전기화학 테스트를 진행한 결과, FeCO3/rGO 복합체는 1,620 mA/g의 전류 밀도에서 50 사이클 이후에도 400 mAh/g의 용량을 유지하 였다. 본 연구는 CO2를 고부가가치 배터리 소재로 전환하여 차세대 에너지 저장 기술에 기여할 가능성을 시사한다.