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        검색결과 5,952

        41.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Research is currently being conducted in the field of carbon reduction–related construction technologies, focusing on using industrial waste as a replacement for cement or as aggregates. However, the existing research is limited as carbon reduction is only achieved by reducing the amount of cement used. With the imperative of carbon neutrality, the development of carbon reduction technology is also necessary in the construction field. To address this, we plan to develop carbon reduction technology by introducing biochar—a carbon-sequestration material—into construction practices. Therefore, this study aims to comprehend the effect of the carbonization degree of biochar on the hydration reaction of cement, emphasizing the development of carbon-sequestration construction technology. Therefore, physical and chemical properties, such as surface and crystal structures, were analyzed to determine the effect of varying carbonization degrees on cement composites, contributing valuable insights into the broader field of sustainable construction.
        4,000원
        42.
        2023.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analyze microstructural changes and evaluate the mechanical properties of TWIP steel subjected to variations in heat treatment, in order to identify optimal process conditions for enhancing the performance of TWIP steel. For this purpose, a homogenization heat treatment was conducted at 1,200 °C for 2 h, followed by hot rolling at temperature exceeding 1,100 °C and cold rolling. Annealing heat treatment is achieved using a muffle furnace in the range of 600 °C to 1,000 °C. The microstructure characterization was performed with an optical microscope and X-ray diffraction. Mechanical properties are evaluated using micro Vickers hardness, tensile test, and ECO index (UTS × Elongation). The specimens annealed at 900 °C and 1,000 °C experienced a significant decrease in hardness and strength due to decarburization. Consequently, the decarburization phenomenon is closely related to the heat treatment process and mechanical properties of TWIP steel, and the effect of the microstructure change during annealing heat treatment.
        4,000원
        43.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Okadaic acid (OA) group toxins, including OA and its analogs, such as dinophysis toxins (DTXs), have been reported to cause diarrheal shellfish poisoning (DSP). These toxins are primarily produced by dinoflagellates and are accumulated in bivalves. Recently, the presence of Dinophysis sp., a causative alga of DSP, has been reported along the coasts of Korea, posing a potential risk of contamination to domestic seafood and exerting an impact on both the production and consumption of marine products. Accordingly, the European Food Safety Authority (EFSA) and the World Health Organization (WHO) have established standards for the permissible levels of OA group toxins in marine products for safety management. Additionally, in line with international initiatives, the domestic inclusion and regulation of DTX2 among the substances falling under the purview of management outlined by the 2022 diarrheal shellfish toxin standard have been implemented. In this study, we reviewed the physicochemical properties of OA group toxins, their various exposure routes (such as acute toxicity, genotoxicity, reproductive and developmental toxicity), and the relative toxicity factors associated with these toxins. We also performed a comparative assessment of the methods employed for toxin analysis across different countries. Furthermore, we aimed to conduct a broad review of human exposure cases and assess the international guideline for risk management of OA group toxins.
        4,200원
        44.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Silkworms have been developed for food and medicinal purposes, and several silkworm products are commercially available. However, there has been no research on their shelf stability. This study investigated the shelf stability of freeze-dried silkworms during storage at various temperature and humidity conditions, using three lipid oxidation indicators: peroxide, acid, and TBA value. The higher the temperature and relative humidity are, the more significant the three lipid oxidation indicators increase. Among these indicators, the TBA and peroxide values show the highest temperature dependence and humidity dependence, respectively. This study could contribute to the standardization of the shelf life of products made from freeze-dried silkworms.
        4,000원
        45.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        막대한 예산이 투입되는 국가연구를 기획·관리·확산하는 연구관리 담당자들은 매우 중요한 인력이나, 역할에 관한 연구는 부족한 실정이다. 본 연구는 연구관리 전문기관 담당자에게 필요한 역량요소를 도출하고 역량의 중요도를 확인하고자 하였다. 이를 위해 4가 지 주요요인과 16개의 하위요인을 도출하였고, AHP 기법을 기반으로 설문조사(연구관리 담 당자와 연구자 90명 대상)를 추진하여 우선순위를 도출하였다. 전체 응답자 기준으로 역량의 중요도는 협력적 태도, 소통능력, 연구지식, 목표관리능력과 신의성실 순으로 확인되었으나, 담당자의 경우, 업무와 관련한 역량(규정지식, 판단능력, 정책지식)이 중요하다고 보는 반면, 연구자들의 경우 자신들을 보다 더 지원해 줄 수 있는 역량(협력적 태도, 소통능력)을 보다 더 중시하는 시각차를 볼 수 있었다. 이번 연구는 전문기관 연구관리 담당자의 채용과 역량 개발에 활용할 수 있을 것으로 사료된다.
        6,600원
        46.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 ESG 경영에 대한 에너지 관련 산업과 기업의 전략적 발전방향 모색을 위하여 글로벌 ESG 경영에서 선도적인 역량과 경험을 갖고 있는 것으로 평가되는 한국중부발전의 사례를 분석해 성공 요인을 도출하고자 하였다. 사례 분석 결과 한국중부발전은 한 발 앞서 ESG 경영에 관심을 갖기 시작해 기후위기 대응과 청정에너지 및 신재 생에너지 사업 분야로 진출하였고, 동반성장과 지역사회 공헌, 부패방지와 윤리경영에 역점을 두고 미래성장과 지 속가능경영을 계속해 객관적인 수치와 실적을 기반으로 우수한 성과를 달성한 것으로 확인되었다. 또한 한국 중부 발전이 글로벌 ESG 경영에 성공할 수 있었던 것은 기존의 글로벌 경영 역량 보유와 이를 제고하고자 전문인력 양 성을 바탕으로 전사적인 조직을 중심으로 하는 지속적인 노력, ESG 리스크에 대한 선제적 관리와 수치목표 중심의 성과관리, 동반성장과 상생경영의 기업문화, 글로벌 ESG 경영에 대한 CEO와 경영진의 판단과 의지가 주요한 요 인으로 작용하였기 때문이라고 분석되었다.
        6,700원
        57.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Determining the size or area of a plant's leaves is an important factor in predicting plant growth and improving the productivity of indoor farms. In this study, we developed a convolutional neural network (CNN)-based model to accurately predict the length and width of lettuce leaves using photographs of the leaves. A callback function was applied to overcome data limitations and overfitting problems, and K-fold cross-validation was used to improve the generalization ability of the model. In addition, ImageDataGenerator function was used to increase the diversity of training data through data augmentation. To compare model performance, we evaluated pre-trained models such as VGG16, Resnet152, and NASNetMobile. As a result, NASNetMobile showed the highest performance, especially in width prediction, with an R_squared value of 0.9436, and RMSE of 0.5659. In length prediction, the R_squared value was 0.9537, and RMSE of 0.8713. The optimized model adopted the NASNetMobile architecture, the RMSprop optimization tool, the MSE loss functions, and the ELU activation functions. The training time of the model averaged 73 minutes per Epoch, and it took the model an average of 0.29 seconds to process a single lettuce leaf photo. In this study, we developed a CNN-based model to predict the leaf length and leaf width of plants in indoor farms, which is expected to enable rapid and accurate assessment of plant growth status by simply taking images. It is also expected to contribute to increasing the productivity and resource efficiency of farms by taking appropriate agricultural measures such as adjusting nutrient solution in real time.
        4,000원
        58.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was aimed to determine the changes in CO2 concentration according to the temperatures of daytime and nighttime in the CO2 supplemental greenhouse, and to compare calculated supplementary CO2 concentration during winter and spring cultivation seasons. CO2 concentrations in experimental greenhouses were analyzed by selecting representative days with different average temperatures due to differences in integrated solar radiation at the growth stage of leaf area index (LAI) 2.0 during the winter season of 2022 and 2023 years. The CO2 concentration was 459, 299, 275, and 239 μmol·mol-1, respectively at 1, 2, 3, and 4 p.m. after the CO2 supplementary time (10:00-13:00) under the higher temperature (HT, > 18°C daytime temp. avg. 31.7, 26.8, 23.8, and 22.4°C, respectively), while it was 500, 368, 366, 364 μmol·mol-1, respectively under the lower temperature (LT, < 18°C daytime temp. avg. 22.0, 18.9, 15.0, and 13.7°C, respectively), indicating the CO2 reduction was significantly higher in the HT than that of LT. During the nighttime, the concentration of CO2 gradually increased from 6 p.m. (346 μmol·mol-1) to 3 a.m. (454 μmol·mol-1) in the HT with a rate of 11 μmol·mol-1 per hour (240 tomatoes, leaf area 330m2), while the increase was very lesser under the LT. During the spring season, the CO2 concentration measured just before the start of CO2 fertilization (7:30 a.m.) in the CO2 enrichment greenhouse was 3-4 times higher in the HT (>15°C nighttime temperature avg.) than that of LT (< 15°C nighttime temperature avg.), and the calculated amount of CO2 fertilization on the day was also lower in HT. All the integrated results indicate that CO2 concentrations during the nighttime varies depending on the temperature, and the increased CO2 is a major source of CO2 for photosynthesis after sunrise, and it is necessary to develop a model formula for CO2 supplement considering the nighttime CO2 concentration.
        4,000원
        59.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 최근 발표된 가이아 자료를 이용하여 늙은 산개성단 M67의 운동학적 연구 결과를 발표하고자 한다. 사전 연구에서 선정한 934개 별들의 분포로부터 성단의 크기 및 구조를 조사하였다. M67의 투영된 중심거리에 따른 구성원의 표면 밀도 분포를 통해 성단 겉보기 반지름과 구성원의 50%를 포함하는 반지름(half-number radius, rh) 을 각각 약 30′(7.6 pc) 및 12.′4(3.1 pc)으로 결정하였다. 또한 이 분포를 King의 밀도 모형에 맞추어 성단 중심부 반지름(core radius, rc) 4.′0(1.0 pc)을 얻었다. 성단의 색-등급도를 등연령 곡선과 비교하여 나이를 약 4 0억 년으로 추정하였 고, 이는 이전 연구의 결과들과 잘 일치한다. 성단 구성원들의 상대적인 고유운동을 조사한 결과, rh보다 안쪽에 위치한 구성원의 고유운동 방향은 등방하게 나타나는 반면, 외곽에 있는 별들은 성단 중심 방향으로 운동하고 있는 것으로 나 타났다. 이것은 성단의 외곽이 수축하고 있다는 것을 의미한다. rc 이내에 분포하는 별들의 시선속도를 분석한 결과, 천 구 상에서 동-서 방향(위치각 100o-280o)으로 놓여있는 축을 중심으로 성단이 회전 하고 있음을 발견하였다. 이것은 성 단의 형성 이후에도 오랜 시간 동안 성단의 회전이 지속될 수 있음을 의미한다. M67이 비리얼 평형 상태에 있다고 가 정하여 계산한 운동학적 질량은 약 1600 M⊙이다. M67의 동역학적 이완시간은 약 1.9억 년 정도로 예상되며 이것은 성단의 나이인 4 0억 년보다 짧다. 그러므로 이 성단은 동역학적으로 이완된 상태라고 할 수 있다. 실제로 성단 중심으 로부터 거리에 따른 별들이 평균 질량이 작아지는 질량분리 현상을 확인하였다.
        4,300원
        60.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the effects of Centella asiatica powder on the quality characteristics and storage stability of goat meat Tteokgalbi. The goat meat Tteokgalbi samples were prepared with four different quantities (0, 0.5, 1, and 1.5%) of Centella asiatica powder. The moisture content of the samples containing Centella asiatica powder was significantly lower than that of the control (p<0.05). The protein content of the samples containing Centella asiatica powder was significantly higher than that of the control (p<0.05). As the proportion of Centella asiatica powder increased, the pH, L*, and a* values of the uncooked and cooked samples decreased (p<0.05). The water holding capacity and the cooking yield of the uncooked and cooked samples were higher in the samples containing Centella asiatica powder than in the control (p<0.05). Also, with the increasing amounts of the Centella asiatica powder, the thiobarbituric acid reactive substance (TBARS) levels decreased. The 1-1.5% Centella asiatica powder group showed lower levels of volatile basic nitrogen (VBN) than the other groups as per the assay (p<0.05). The results indicate that Centella asiatica powder could enhance the quality characteristics and storage stability of goat meat Tteokgabi.
        4,000원
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