Ultra-high temperature ceramics (UHTCs) exhibit extremely high melting points (> 2,500 °C) and maintain structural stability under severe conditions. However, their intrinsic brittleness and oxidation vulnerability limit their direct application in aerospace components exposed to extreme environments. To overcome these limitations, UHTC-based composites reinforced with secondary phases such as ZrO2 are required to improve fracture toughness and oxidation resistance. The polymer infiltration and pyrolysis (PIP) process provides a promising fabrication route for such composites, offering densification of porous matrices with liquid precursors while maintaining uniform microstructures. Here, we report a novel zirconia precursor (PZC-12) synthesized through a sol-gel reaction of zirconium propoxide with acrylic acid (1:2 molar ratio). The liquid precursor exhibited a suitable viscosity (~518 cP) and enabled dual crosslinking via hydroxyl condensation combined with radical polymerization of vinyl groups. Consequently, effective thermal curing was accomplished upon heating at 80 °C for 12 h. This strategy minimized premature decomposition and achieved a high ceramic yield of 52.7 %. Pyrolysis at 600 °C in air produced nanosized t-ZrO2, which transformed into m-ZrO2 with grain growth at higher temperatures. Applied in PIP, a ZrB2-ZrO2 composite was successfully fabricated, demonstrating that dual crosslinking is critical for high-yield, reliable PIP-based UHTC composites.
This study proposes a Dispersion-Induced Decarburization (DID) process using polar solvents to address the degradation of luminescence efficiency in SrAl2O4:Eu phosphors caused by carbon contamination from carbon crucibles during high-temperature synthesis. Conventional high-temperature oxidation treatments are effective for carbon removal but induce the oxidation of Eu2+ ions and structural collapse of the SrAl2O4 host, resulting in severe degradation of luminescence properties. The proposed DID process physically removes carbon impurities by dispersing SrAl2O4:Eu powders in highly polar solvents such as distilled water (DI), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), and N,N-dimethylformamide (DMF). Among them, DI exhibited the highest purification efficiency, completely eliminating carbon-related diffraction peaks. As a result, the photoluminescence quantum yield (PLQY) of SrAl2O4:Eu improved from 32 % to 50 %, and a maximum PLQY of 55.2 % with a luminance of 6,000 cd・m-2 was achieved for the 20 mol% Eu-doped powder. This work presents a novel and effective purification strategy that overcomes carbon contamination in SrAl2O4:Eu phosphors, significantly enhancing their luminescence efficiency without structural damage.
National parks serve as protected areas that ensure the sustainable use of representative natural ecosystems. In South Korea, approximately 46% of the nation’s total species and 65% of its endangered species inhabit national parks. Comprehensive resource surveys have been conducted every 5 years in accordance with the Natural Parks Act to safeguard these invaluable biological resources. However, species identification in these surveys still largely relies on traditional methods, which are time-consuming and labor-intensive, and often subject to investigator bias. This study investigated freshwater fish communities in stream ecosystems at four national parks-Seoraksan, Woraksan, Deogyusan, and Hallyeohaesang-using environmental DNA (eDNA) metabarcoding to evaluate the consistency of its results with those of conventional surveys. A total of 33 fish species (five orders, 11 families) were recorded in both methods. eDNA detected 31 species (detection rate: 93.9%), whereas conventional methods identified 22 species (66.7%). However, species richness values were significantly correlated between the two methods. eDNA exhibited higher detection efficiency (88.7-100.0%) across all parks than conventional methods (64.3-72.2%). Six endangered species were identified in total, four of which (66.7%) were detected by eDNA. The results indicate that eDNA metabarcoding provides a more sensitive, efficient, and reliable tool for assessing freshwater fish diversity in national parks than conventional methods. Overall, eDNA offers a valuable complement or potential alternative to conventional survey methods for the long-term monitoring of freshwater fish biodiversity.
This study aimed to identify the optimal winter storage temperature for preserving bulbil vigor and enhancing the efficiency of spring bulbil cultivation in garlic. Bulbils from the cultivars ‘Daeseo’ and ‘Hongsan’ were categorized into three size grades (#1: <3 mm; #2: 3–4 mm; #3: 4–5.5 mm) and stored for five months (September 2024–February 2025) under four conditions: conventional warehouse storage, 4°C, 15°C, and 25°C. The bulbils were sown in rows in an open field on 20 February 2025 and harvested on 30 May 2025. After curing for 2–3 days and air-drying for about one month, the harvested bulbs were evaluated for the number and characteristics of round bulbs. For both ‘Hongsan’ and ‘Daeseo’, storing bulbils in either a conventional warehouse or at 4°C during winter resulted in higher harvest rates. Larger bulbils consistently produced a greater number of harvested bulbs and heavier bulb weights. In ‘Hongsan’, only the #3 bulbils stored at 25°C yielded a small proportion ( 1. 2%) of multi-clove bulbs, while a ll o ther treatments resulted in single-clove bulbs exclusively. Mean bulb weight was lowest after storage at 25°C and tended to be higher under warehouse storage. In ‘Daeseo’, there was no significant difference in harvest percentage between warehouse and 4°C storage; however, the mean harvest percentage was higher and the variation among replicates was lower at 4°C. Notably, multi-clove bulbs were observed only with warehouse storage (#2: 0.35%; #3: 1.8%), while 4°C storage resulted exclusively in single-clove bulbs. Mean bulb weight increased with bulbil size across all treatments, and conditions that produced more multi-clove bulbs generally also showed heavier mean bulb weights. Overall, for spring cultivation of bulbils, 4°C storage is optimal for enhancing single-clove bulb production in ‘Daeseo’, while conventional winter storage is sufficient for ‘Hongsan’.
This study examined the structural, physicochemical, and functional characteristics of five black soybean (Glycine max (L.) Merr.) cultivars—Cheongja5, Danheuk, Socheongja, Seum, and Soriheuk—bred and cultivated in Korea. We conducted comprehensive analyses on morphology, microstructure, thermal and hydration properties, pasting behavior, and antioxidant activity to identify cultivar-specific differences in processing suitability and functional properties. The results indicated significant varietal variations in seed coat ratio, cotyledon density, and color, which affected thermal stability, hydration, and viscosity development during heating. Cultivars with compact cotyledon matrices, such as Cheongja5 and Danheuk, displayed high enthalpy (ΔH), low solubility, and limited viscosity development, suggesting high structural stability and low thermal reactivity-traits favorable for thermally stable or beverage-type applications. In contrast, cultivars with looser structures and greater surface exposure, like Seum and Socheongja, exhibited higher swelling power, dispersion stability, and RVA viscosities, indicating their suitability for viscous or semi-solid systems. Notably, Soriheuk showed the highest antioxidant activity and levels of phenolic and flavonoid compounds, correlating with its high seed coat ratio and dark pigmentation, positioning it as a promising functional ingredient. These findings underscore that the physicochemical and structural diversity among black soybean cultivars significantly influences their processing performance and functional potential, providing a scientific foundation for selecting and developing functional cultivars.
This review summarizes recent insights into the effects of foods and natural products on brain function, focusing on neuron-glia interactions and the Gut-Brain Axis. Bioactive compounds such as polyphenols, omega-3 fatty acids, curcumin, and ginsenosides exert neuroprotective effects by attenuating oxidative stress and neuroinflammation through activation of the Nrf2/ARE signaling pathway and suppression of NF-?B-mediated inflammatory cascades. They also enhance synaptic plasticity via the CREB-BDNF pathway, improving learning and memory function. Fermented foods and microbiota-related metabolites, particularly short-chain fatty acids (SCFAs), modulate the Gut-Brain Axis, leading to increased hippocampal BDNF expression and emotional stability. Traditional Korean fermented foods and marine-based dietary components further contribute to the regulation of neuron-glia networks, providing a scientific rationale for the neurofunctional benefits embedded in Korean dietary culture. This review highlights that food-derived bioactive components act not only as nutrients but also as neuromodulatory agents maintaining brain homeostasis. Future perspectives emphasize integrating molecular neuroscience with food culture research to advance the emerging field of food neuroscience and promote functional food innovation grounded in traditional dietary wisdom.
The purpose of this study is to develop and implement a customized AI-based speaking diagnosis, learning, and assessment system, SpeakMaster, in order to overcome the lack of systematic evaluation and practice opportunities in school English speaking class. This system integrates automated speaking scoring to provide students with feedback on their speaking abilities across pronunciation, conversation, and presentation. This study adopts a design-based research methodology, demonstrating the development and implementation process. 1,451 students and eight teachers in elementary, middle, and high schools participated in the experiment. Data were collected through learning logs, teacher journals, interviews, and post-surveys. The findings indicate that the system design is appropriate for English class, promoting students’ flow in engaging speaking practice. Students showed motivation and satisfaction while teachers found the system valuable for monitoring student progress and facilitating speaking assessments. Despite the challenges of improving chatbot performance and enhancing scoring reliability, the results suggest that SpeakMaster shows potential to enhance English speaking education.
기후변화로 인한 고탁도, 조류 발생 심화나 과불화화합물(PFAS, Per- and Polyfluoroalkyl substances) 검출 등 취수원 수질 이슈가 최근 빈번하게 발생하고 있으며, 취수원 수질 변동성이 심화되고 있다. 이러한 문제 해결을 위해 다수의 정수장에 대하여 고도정수처리공정 도입이 검토되고 있으나, 현행 지침은 취수원의 잠재적 수질 위험을 반영하기 어려워 실질적 검토에 한계가 있다. 이를 개선하기 위해 본 연구에서는 취수원 수질특성을 반영하여 수질 잠재위험을 정량적으로 평가할 수 있는 체계를 제시하였다. 8개 취수원을 대상으로 2024년 8∼10월 동안 18개 수질항목을 조사하고, 일반수질, 수질등급, 맛냄새 유발, 소독부산물 생성, 색도 유발 등 5개 평가항목을 설정하여 평가를 실시하였다. 정량평가를 통해 취수원 수질여건 점수를 산정하고, 5개 등급으로 구분되는 선택취수 가능도 등급을 제안하였다. 평가 결과, A1취수탑(73.6점, E등급), A2취수탑(73점, E등급), F댐(67.3점, E등급)은 수질 잠재위험성이 매우 크게 평가되어 고도정수처리공정의 우선 도입 검토가 필요할 것으로 판단되었다. 수심별 평가결과 취수원에 따라 적절한 선택취수 지점은 상이하며, 본 연구방법에 의해 선택취수 지점 의사결정에도 활용할 수 있을 것으로 판단되었다. 월별 평가결과 8∼9월의 수질여건이 10월보다 열악하였으며, 강우 등 계절적 특성이 수질여건에 반영된 결과로 추정되었다. 본 연구에서는 취수원 수질여건 점수와 선택취수 가능도 등급이라는 정량평가 지표를 제시하여 취수원 수질에 따른 잠재위험 평가방법론을 제안하였으며, 향후 고도정수처리 도입 검토 의사결정에 활용될 수 있을 것으로 기대된다.
본 연구는 생성형 AI 창작의 확산으로 인간 창작자의 음악적 사고력과 분석 능력을 강화하는 교육의 필요성이 커짐에 따라 실용음악 화성학 교육 현황을 재점검이 요구되고 있다. 이에 실용음 악 전공생을 대상으로 화성학에 대한 사전 인식과 음악 인지 능력을 탐색적으로 조사하여 실용음 악 화성학 교육의 현황을 진단하고 향후 교수법의 방향성을 제시하고자 하였다. 이를 위해 음악 인지 능력을 청각적, 이론적, 해석적, 창의적 인지의 네 영역으로 구분하고 총 40문항의 설문조사 를 실시하였다. 연구 결과 화성학 교육의 필요성 인식은 평균 4.47점으로 매우 높았고, 기초 화성 지식 역시 3.77점으로 안정적 수준이었다. 하지만 청각적, 해석적, 창의적 인지 능력은 각각 2.4 점, 2.78점, 2.21점으로 모두 보통 이하로 나타났다. 이는 실용음악 화성학 교육이 이론 중심의 전달식 학습에 머물러 있음을 시사한다. 이에 본 연구는 청각 기반 인지 강화, 구조적 이해 속 감정적 해석과 실습 중심 학습의 필요성, 마지막으로 수준별 학습 체계 구축을 제안하였다. 본 연구는 학습자의 사전 인지 능력 분석을 토대로 실용음악 화성학 교육의 효율성과 지속가능성을 높이고자 통합적 학습 구조를 제안하였다. 이는 이론과 감성, 분석과 창작이 균형을 이루는 감각 적 사고 기반 교육으로의 필요성을 시사한다.
The accelerator pedal of a KLTV was applied in the form of a carryover utilizing the products of a civilian vehicle. There was case in which it was damaged because it did not reflect the military's specificity, Therefore the material and shape of the accelerator pedal were improved to confirm the strength improvement effect of about 86%, It can prevent accidents and contribute to securing mobility by presenting and applying fracture strength standards suitable for the military operation environment.
전기추진 선박의 추진축계 이상상태는 심각한 선박 운항 장애를 초래할 수 있으므로, 추진 시스템의 상태를 정확히 진단하고 사전에 예방 유지보수를 수행하는 Prognostics and Health Management(PHM) 기술의 필요성이 증가하고 있다. 본 연구에서는 전기추진 선박 의 추진축 이상상태를 조기에 감지하고 진단하기 위하여 진동 데이터를 기반으로 한 머신러닝 기반 PHM 시스템의 개발과 성능 평가를 수행하였다. Land-Based Testing System(LBTS) 시스템에서 수집된 정상 상태와 축 정렬 이상 상태(0.5 mm, 1.0 mm, 1.5 mm)의 진동 데이터를 활용하여 데이터 전처리 및 특성 추출을 수행하였다. 연구에서는 Fully Connected Neural Network(FCNN) 및 Convolutional Neural Network(CNN)을 적용하여 이상 상태를 진단하는 모델을 개발하고 비교 분석하였다. FCNN 기반 모델은 단순한 구조로 빠른 학습이 가능 하여 실시간 모니터링에 적합한 반면, CNN 모델은 미세한 상태 변화를 효과적으로 탐지하는 데 탁월한 성능을 보였다. 성능 평가 결과 FCNN 모델은 평균 95% 이상의 정확도를 나타냈으며, CNN 모델은 이보다 더욱 향상된 성능을 제공하였다. 본 연구를 통해 개발된 진동 기반 PHM 시스템은 전기추진 선박 추진축 이상상태를 효과적으로 조기에 진단할 수 있는 능력을 입증하였다. 이러한 연구 성과는 전기 추진 선박의 안전하고 효율적인 운항을 위한 신뢰성 높은 유지보수 전략 수립에 중요한 기여를 할 것으로 기대된다. 향후 연구로는 데이 터 품질 개선 및 추가적인 딥러닝 모델 적용을 통한 성능 향상을 목표로 한다.
Common benign oral soft‑tissue lesions include irritation fibroma and cemento‑ossifying fibroma (COF). Complete surgical excision is the standard treatment. We describe two cases where the overlying oral mucosa was recycled as an autologous free mucosal graft to cover the surgical defect. In both cases, the lesions were excised with tumor‑free margins. The overlying mucosa was dissected, trimmed, and adapted as a free mucosal graft to cover the defect, fixed with sutures to minimize micromotion. A soft diet and hygiene instructions were provided. This report highlights two cases where the overlying normal oral mucosa was preserved as a free mucosal graft after complete excision of irritation fibroma and cemento‑ossifying fibroma. The technique respected the principle of complete excision, avoided additional donor‑site morbidity, and achieved favorable tissue integration. While prior literature described these lesions as submucosal nodules covered by normal mucosa, systematic use of the preserved mucosa for reconstruction has not been reported. However, this report have limitations, including the small sample size and restricted follow‑up. A free mucosal graft from overlying oral mucosa may be a simple, cost‑effective, and practical option for reconstruction of small to medium intraoral defects when appropriately indicated.
2023년 경상남도 함안군 소재 포장내 재배중인 적갓의 지제부위의 줄기와 잎자루에서 흰비단병 증상이 발생하였다. 병징은 적갓의 지제부위의 줄기와 잎자루 아랫부분이 수침상으로 물러져 부패되어 서서히 시들고 결국 식물 전체가 말라 죽는다. 토양과 맞닿은 부위의 줄기와 잎자루에서 흰색의 곰팡이 균사체가 발생하였고 갈색의 작고 둥근 균핵이 많이 형성되었다. 감자한천배지에서 배양한 균총 역시 흰색을 띠고 시간이 지남에 따라 갈색의 작고 둥근 균핵이 형성되었다. 균핵의 크기는 1-3 mm이며 균사의 폭은 4-9 μm였다. 균사 성장과 균핵 형성의 적온은 30℃이었다. 흰비단병 균사특유의 clamp connection이 관찰되었다. 적갓에서 발생한 병징과 병원균의 균학적 특징, ITS rRNA 영역의 염기서열을 비교 분석한 결과, 이 병을 Athelia rolfsii에 의한 적갓 흰비단병으로 동정하였다. 병원성 검정은 코흐의 가설을 바탕으로 수행하였는데, 접종 6일 후 적갓 지제부위의 줄기와 잎자루가 서서히 수침상으로 물러지면서 부패하였다. 접종부위에 솜털모양의 흰색 균사가 왕성하게 자라면서 균핵 시원체가 생기고 시간이 지남에 따라 다시 갈색의 작고 둥근 균핵이 많이 형성되어 흰비단병 특유의 병징이 나타났고 무처리에서는 아무런 이상 증상이 유도되지 않았다. 코흐의 가설에 따라 병징이 있는 부위에서 병원체 재분리를 수행하였다. 이 연구는 국내 적갓에서 발생한 A. rolfsii에 의한 흰비단병의 최초 보고로 병 발달에 대한 역학조사 및 병 방제를 위한 전략 수립에 귀중한 정보를 제공하리라 여겨진다.