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        검색결과 1,634

        21.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The feathery branched green alga Bryopsis plumosa (Hudson) C. Agardh bloomed at Songji Beach, Haenam, Korea, in November 2022. A terrible stench was present on the beach, and the bottom was covered in a thick green mat of green algae. The alga was identified as B. plumosa, which is an opportunistic species currently distributed worldwide. Dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) were analyzed in the bloomed area and compared with those of other vicinities. The DIN and DIP concentrations were 1.067 and 0.461 mg L-1, respectively, which were 6 to 19 times higher than the average concentrations on southwest coasts, including Haenam. The B. plumosa bloom at Songji Beach in November 2022 appears to have depended on DIN and DIP concentrations in seawater. In this study, we report on the mass occurrence of B. plumosa, which appeared for the first time in Korea. This occurrence was found to be closely related to the concentration of nutrients in seawater. Therefore, it is necessary to manage the concentration of nutrients on land flowing into coastal waters to control green algal blooms such as Bryopsis.
        4,000원
        22.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The waste secondary battery contains a significant amount of valuable metals, making its recycling highly desirable. However, conventional chemical methods for recycling are environmentally unfriendly and cost-ineffective. Rather than the chemical method, this paper deals with a mechanical method for recovering electrode materials from waste secondary batteries by blowing pressurized air onto the interface area between the electrode and the separator. Especially, in this study, the effective blowing angle were searched by simulating the separation of the electrode material from the separator through 1-way fluid structure interaction analysis based on the Cohesive Zone Modeling technique.
        4,000원
        23.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a core-shell powder and sintered specimens using a mechanically alloyed (MAed) Ti-Mo powder fabricated through high-energy ball-milling are prepared. Analysis of sintering, microstructure, and mechanical properties confirms the applicability of the powder as a sputtering target material. To optimize the MAed Ti-Mo powder milling process, phase and elemental analyses of the powders are performed according to milling time. The results reveal that 20 h of milling time is the most suitable for the manufacturing process. Subsequently, the MAed Ti-Mo powder and MoO3 powder are milled using a 3-D mixer and heat-treated for hydrogen reduction to manufacture the core-shell powder. The reduced core-shell powder is transformed to sintered specimens through molding and sintering at 1300 and 1400oC. The sintering properties are analyzed through X-ray diffraction and scanning electron microscopy for phase and porosity analyses. Moreover, the microstructure of the powder is investigated through optical microscopy and electron probe microstructure analysis. The Ti-Mo core-shell sintered specimen is found to possess high density, uniform microstructure, and excellent hardness properties. These results indicate that the Ti-Mo core-shell sintered specimen has excellent sintering properties and is suitable as a sputtering target material.
        4,000원
        24.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 컨테이너 육묘 시스템을 활용한 참외 접목 묘의 안정적인 생산 가능성을 평가하는 것이었다. 이를 위해, 컨테이너 육묘 시스템과 고온 조건의 플라스틱 온실에서 육묘 한 접수와 대목, 접목묘의 생육을 비교 분석하였다. 접목활착 후 육묘 환경에 따른 참외 접목묘의 생육과 묘소질을 0일, 4일, 7일, 11일, 14일째에 비교하였다. 컨테이너 육묘 시스템에서 는 주야간 온도를 25/20°C, 상대습도를 70%로 설정하여 재 배기간 동안 안정적으로 유지하였으며, 플라스틱 온실 내의 주야간 평균온도는 28.1/15.4°C로 주야간 온도차(DIF)가 더 크게 나타났다. 조사기간 동안 참외 접목묘의 초장은 플라스 틱 온실 육묘 처리구에서 컨테이너 육묘 시스템 처리구보다 더 길게 나타났다. 참외 접목묘 조직의 충실도는 지상부 건물 중을 초장으로 나누어 계산하였다. 육묘장에서 접목한 묘는 접목 후 7-10일 경과하여 활착이 완료되고 초장이 10cm 내 외일 때 출하하여 정식에 이용되게 된다. 본 연구에서 접목활 착 후 7일째에 컨테이너 육묘 시스템에서 재배된 묘의 충실도 는 44.9±2.64mg/cm으로 나타났으며, 플라스틱 온실 육묘 처 리구에서는 24.4±1.56mg/cm로 나타났다. SPAD 평균은 플 라스틱 온실 육묘에서 30.5, 컨테이너 육묘 시스템에서 41.1 로 측정되었다. 이러한 결과는 컨테이너 육묘 시스템의 활용 이 고온기 또는 저일조 시기와 같은 육묘 환경에서도 고품질 모종을 안정적으로 생산할 수 있는 것을 확인하였고, 인공광 을 이용한 육묘 시스템의 활용 범위가 앞으로 더 확대될 것으 로 기대된다.
        4,000원
        25.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4차 산업혁명의 도래로 인한 기술혁신은 자율운항선박을 중심으로 해상 운송분야까지 활발한 발전을 불러왔다. 특히, 현재의 선원이 직접 운항하는 방식인 유인선박 사이에서 운항하게 될 자율운항선박은 자율도에 따라 원격제어를 통해 운항을 수행하며, 육상에 서 이를 제어할 원격운항자에 대한 관심 또한 늘어나고 있다. 하지만 아직 원격운항자가 개입이 필요한 상황이 동시에 발생하는 등을 고 려한 원격운항자 최소 인력 요구사항에 대한 연구는 부족한 상황이다. 본 연구는 특정 해역 구간의 누적된 항적데이터를 활용하여 선박 간에 발생할 수 있는 조우상황에서 원격운항자의 개입이 필요한 상황을 정의하고, 해당 구간을 특정 규모의 자율운항선박 선대로 운항하 였을 때, 원격운항자의 개입이 동시에 필요한 상황이 얼마나 발생하는지를 시뮬레이션을 통해 확인하였다. 연구의 결과는 향후 실제 자율 운항선박 선대를 운행할 원격운항센터의 원격운항자의 적정인력 배치 등의 계획 또는 정책 수립에 활용될 기초 자료로 활용될 것으로 기 대한다.
        4,000원
        26.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the diversity of butterfly communities inhabiting agroecosystems and examined the effect of latitude and longitude. The ecological characteristics of butterflies inhabiting rural ecosystems, such as habitat preference and food plant range, were also examined. This study was conducted from 2019 to 2022, selecting 10 locations nationwide and conducting line transect surveys every two weeks for four years, confirming a total of 112 species and 21,901 individuals. There was no difference in the number of species and individuals by region, but there was a clear difference in community composition. The most abundant species in rural ecosystems were Pieris rapae, Polygonia c-aureum, Zizeeria maha, and Colias erate, in that order. There was no significant difference in the number of species and individuals by latitude and longitude, indicating no peninsula effect. Habitat preference showed that butterflies preferring grasslands and forest edges were much more common than those preferring the forest interior, and the food breadth was mostly oligophagous, followed by monophagous and polyphagous. Butterflies inhabiting agroecosystems had ecological characteristics that preferred open spaces such as grasslands and forest edges or relatively diverse foods, due to the similarity of the environmental characteristics of the survey points. Through this study, we believe that continuous monitoring is necessary to determine whether climate change, which is currently underway and habitat change are affecting butterflies in agroecosystems.
        4,000원
        27.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mulberry fruit is a superior source of polyphenols, especially anthocyanin, and has a long history of use as an edible fruit and traditional medicine. The anthocyanin composition of mulberry fruit from 15 Korean cultivars was analyzed by ultra-performance liquid chromatography diode array detector with quadrupole time of flight/mass spectrometry (UPLC-DAD-QToF/MS) based on a cyanin internal standard. The four glycosides were identified by comparison with authentic standards and published reports. The major anthocyanin was cyanidin 3-O-glucoside (71.7%), followed by cyanidin 3-O-rutinoside (26.6%). The minor components (total of 1.7%) were pelargonidin 3-O-glucoside and pelargonidin 3-O-rutinoside. The total anthocyanin content (mg/100 g, dry weight) of mulberry fruit varied by cultivar and ranged from 471.5±4.0 (Su Hong) to 4,700.2±54.0 (Gwa Sang2). Among the 15 cultivars examined, Gwa Sang2 showed the highest level of cyanidin 3-O-glucoside (3,133.4±32.6), which was 9-fold higher than that of Su Hong (351.5±3.4). In conclusion, anthocyanin profiles, including pelargonidin 3-O-glucoside and pelargonidin 3-O-rutinoside, were reported for the first time from 15 Korean mulberry fruit cultivars. The results will contribute valuable information on pharmaceutical properties, breeding superior mulberry cultivars, and food industries.
        4,000원
        28.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the antioxidant activities of wine made with aronia (Aronia melanocarpa). The ethanol concentration of the aronia wine was increased up to 7.8±0.1% on the 8th day of fermentation. Compared to other types of wine, the total amount of organic acids was highest in raspberry wine, followed by grape wine, arona wine, and aronia juice. Because, acetic, oxalic, and succinic acids were not detected in the aronia juice, but were detected in the aronia wine, it was determined that they were produced during alcohol fermentation. The polyphenol content in the aronia juice and wine was higher than in the grape wine and raspberry wine and was twice as much in the aroni wine than in the aronia juice. The flavonoid content in aronia juice and wine was higher than in commercial grape wine and raspberry wine. The DPPH radical scavenging ability was higher than 50% in the aronia wine and juice samples. ABTS radical scavenging activity was higher in aronia juice and wine than in raspberry wine and grape wine. The results of this study suggest that the development of wine with high antioxidant activity is possible if wine is made with aronia.
        4,000원
        29.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 고투과성 및 높은 염 제거율을 가지는 역삼투막의 성능향상을 위하여 다양한 첨가제 및 계면중합 시 경화 온도 및 시간에 따른 특성평가에 대한 연구가 수행되었다. 첨가제가 없는 막과 첨가제를 첨가한 막의 모폴로지는 모 두 “ridge-and-valley” 구조를 나타내어, 폴리아미드 층이 다공성 지지층 표면에 성공적으로 중합되었음을 확인하였다. 또한 2-Ethyl-1,3-hexanediol (EHD) 첨가함으로써 향상된 친수성과 수투과율 가졌으며, 이는 접촉각 측정을 통해서 확인되었다. 최 종적으로 97.78%와 98.7%의 NaCl 및 MgSO4 제거율과 3.31 L/(m2⋅h⋅bar)의 높은 수투과율을 가진 고투과성 계면중합막을 제조하였다.
        4,300원
        30.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tomato is one of the major widely cultivated crops around the world. The leaf area is directly related to the total amount of photosynthesis, which affects the yield and quality of the fruit. Traditional methods of measuring the leaf area are time-consuming and can cause damage to the leaves. To address these problems, various studies are being conducted for measuring the leaf area. In this study, we introduced a model to estimate the leaf area using images of tomatoes. Using images captured by a camera, we measured the leaf length and width and used linear regression analysis to derive the leaf area estimation formula. Furthermore, we used a Neural Network (NN) for additional analysis to compare the accuracy of the models. Initially, to verify the reliability of the image data, we conducted a correlation analysis between the actual measurement data and the image data, which showed a high positive correlation. The leaf area estimation model presented 23 estimation formulas. We used regression analysis to estimate the coefficients of each model and also used employed an artificial neural network analysis to derive high R-squared (R2) values and low Root Mean Square Error (RMSE) values. Among the estimation formulas, the ninth model showed the highest reliability with an R-squared value of 0.863. We conducted a verification experiment to confirm the accuracy of the selected model, and the R-squared value was 0.925. This study confirmed the reliability of data measured from images and the reliability of the leaf area estimation model using image data. These methods are expected to be an important tool in agriculture, using imaging equipment for measuring and monitoring the crop growth.
        4,000원
        38.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, In this study, structural analysis of a fuel tank for an SUV (sports utility vehicle) was performed for crack prevention design. Reservoir tank analysis was conducted for crack prevention design, and improvement measures for weak areas were discovered and reflected in the design. Pressure analysis was performed on the existing model to analyze weak areas. As a result of analysis through various design changes, it was found that the strength problem of the reservoir tank was due to the discontinuity of the rib inside the tank, and to improve this, it was necessary to minimize the discontinuity section.
        4,000원
        39.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The need for lightweight yet strong materials is being demanded in all industries. Carbon fiber-reinforced plastic is a material with increased strength by attaching carbon fiber to plastic, and is widely used in the aerospace industry, ships, automobiles, and civil engineering based on its low density. Carbon-reinforced fiber plastic is a material widely used in parts and manufactured products, and structural analysis simulation is required during design, and application of actual material properties is necessary for accurate structural analysis simulation. In the case of carbon-reinforced fiber plastics, it is reported that there is a porosity of around 0.5% to 6%, and it is necessary to check the change in material properties according to the porosity and pore shape. It was confirmed by applying the method. It was confirmed that the change in elastic modulus according to the porosity was 10.7% different from the base material when the porosity was 6.0%, and the Poisson's ratio was confirmed to be less than 3.0%. It was confirmed that the elliptical spherical pore derived different material properties from the spherical pore depending on the pore shape, and it was confirmed that the shape of the pore had to be confirmed to derive equivalent material properties.
        4,000원
        40.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tomatoes in greenhouse are a widely cultivated horticultural crop worldwide, accounting for high production and production value. When greenhouse ventilation is minimized during low temperature periods, CO2 enrichment is often used to increase tomato photosynthetic rate and yield. Plant-induced electrical signal (PIES) can be used as a technology to monitor changes in the biological response of crops due to environmental changes by using the principle of measuring the resistance value, or impedance, within the crop. This study was conducted to investigate the relationship between tomato growth data, vital response, and PIES resulting from CO2 enrichment in greenhouse tomatoes. The growth of tomato treated with CO2 enrichment in the morning was significantly better in all items except stem diameter compared to the control, and PIES values were also higher. The growth of tomato continuously applied with CO2 was better in the treatment groups than control, and there was no significant difference in chlorophyll fluorescence and photosynthesis. However, PIES and SPAD values were higher in the CO2 treatment group than control. CO2 enrichment have a direct relationship with PIES, growth increased, and transpiration increased due to the increased leaf area, resulting in increased water absorption, which appears to be reflected in PIES, which measures vascular impedance. Through this, this study suggests that PIES can be used to monitor crops due to environmental changes, and that PIES is a useful method for non-destructively and continuously monitoring changes of crops.
        4,000원
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