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        검색결과 1,241

        61.
        2023.11 구독 인증기관·개인회원 무료
        Spent nuclear fuels (SNFs) are stored in nuclear power plants for a certain period of time and then transported to an interim storage facility. After that, SNFs are finally repackaged in a disposal canister at an encapsulation plant for final disposal. Finland and Sweden have already completed the design of the spent nuclear fuel encapsulation plant. In particular, Finland has begun the construction of the encapsulation plant and is on the verge of completion. Korea Radioactive Waste Agency (KORAD) is conducting a conceptual design of a deep geological repository for SNFs. Conceptual design of the encapsulation plant is part of the research activity. It is highly required to draft an operation process of the encapsulation plant before an actual design activity. As part of the activity, Finnish design concept of the encapsulation plant and experience were thoroughly reviewed. Finally a preliminary concept of the operation process was proposed considering Korean unique situations such as the volume of SNFs estimated to be disposed of, types of transportation cask and other considerations.
        62.
        2023.11 구독 인증기관·개인회원 무료
        Recently, as carbon-neutral energy sources become increasingly important worldwide, SMRs (Small Modular Reactors), which offer significantly enhanced safety, versatility, and mobility compared to conventional nuclear reactors, are gaining attention as a viable alternative. SMR generally refers to small modular reactors with a power output of 300 MWe or less. Unlike conventional reactors, SMRs are characterized by an all-in-one design where peripheral systems and equipment are all integrated into the reactor itself, leading to enhanced reliability and durability. Additionally, the nuclear fuel reloading cycle is significantly extended compared to traditional reactors, resulting in a substantial reduction in maintenance difficulty and costs. Researchers have taken note of these characteristics of SMRs, particularly the extended fuel reloading cycle. Therefore, we have initiated the initial design of an ultra-small Micro Modular Reactor with an electricity generation capacity of 10 MWe and a fuel cycle of up to 55 years, with the goal of using it as a propulsion power source for various transportation modes, especially ships. Our design of MMR, called ‘ARA,’ is primarily distinguished by its use of U233 and Th232 fuels instead of conventional UO2 fuel. Due to various features of ‘ARA,’ including different fuel compositions, ARA is predicted to exhibit several characteristic features compared to conventional PWRs. In this study, among these characteristics, we focused on predicting changes in material composition within the fuel rod during the extended cycle operation of high-enriched fuel, rather than short-cycle operation using low-enriched fuel, unlike conventional reactors. The primary goal of this research is to observe the behavior of the composition of the materials used in the fuel cycle of the MMR, which utilizes U233 and Th232 fuels instead of UO2. Considering the difficulties in the spent nuclear fuel disposal process, many different trials were made to minimize the fission products of ARA, which differs from conventional reactors in terms of fuel type, size, and fuel cycle, in relation to waste generation.
        63.
        2023.11 구독 인증기관·개인회원 무료
        In KNF, fuel performance analysis modules were developed to predict the overall behavior of a fuel rod under normal operating conditions. Their main focus is to provide information on initial conditions prior to dry storage. Potential degradation mechanisms that may affect sheath integrity of spent CANDU fuel during dry storage are: creep rupture under internal gas pressure, sheath oxidation in air environment, stress corrosion cracking, delayed hydride cracking, and sheath splitting due to UO2 oxidation for a defective fuel. To upgrade the developed modules that address all the damage mechanisms, the first step was a review of the available technical information on phenomena relevant to fuel integrity. The second step was an examination of the technical bases of all modules, identify and extend the ranges of all modules to required operating ranges. The 300°C spent CANDU fuel sheath temperature metric for dry storage ensures spent CANDU fuel element integrity from the failure mechanisms of creep rupture, oxidation and stress corrosion cracking at a failure probability of 2×10-5 for a dry storage time of 100 years. The 300°C sheath temperature metric for dry storage has relatively a lower failure rate than the target criteria for dry storage of spent LWR fuel. Although different modes of failure were treated separately for simplicity, ignoring possible synergistic effects, these results are conservative because of the conservative assumptions that have been made for evaluating spent fuel element conditions, and because of the inherent conservatism of the applied models. Additional conservatism of the model comes from the fact that isothermal conditions do not prevail in actual storage conditions. Further R&D being considered includes acquisition of new functional models to implement overall fuel behavior evaluation and cover spent CANDU fuel in dry storage, and upgrades of the analysis module to achieve sufficient accuracy in key output parameters. The developed modules provide a platform for research and industrial applications, including the design of fuel behavior experiments and prediction of safe operating margins for spent CANDU fuel.
        66.
        2023.10 구독 인증기관·개인회원 무료
        본 연구는 남한 지역에서 서식하는 멸종 위기 종 2급인 왕은점표범나비의 기후 변화에 따른 서식지 변화를 분석하고자 한다. 이를 위해 단일모델의 장단점을 보완하기 위해서 생물 보전과 동물 생태학 분야에서 널리 사용 되는 앙상블 모델을 활용하여 기후변화 시나리오 자료를 이용하여 현재와 미래 기후 조건에서의 잠재적 서식지 변화를 평가하였다. 연구 결과에 따르면, 미래에는 왕은점표범나비의 서식지가 줄어들 것으로 예상되며, 이 변화 는 기온과 강수량 모두에 영향을 받을 것으로 나타났다. 특히 강수량의 계절적 변동이 가장 큰 영향을 미칠 것으로 분석되었다. 이러한 결과는 기후 변화로 인한 생물종의 서식 분포의 이해를 향상시켜 멸종 위기 종 관리와 생태계 복원과 같은 다양한 분야에서 생물다양성 증진을 위한 중요한 기초 데이터로 활용될 것으로 기대된다.
        67.
        2023.10 구독 인증기관·개인회원 무료
        Biological control in agriculture is an eco-friendly pest management method. Numerous parasitoid wasps have been utilized as natural enemies and biological control agents. However, due to a shortage of fundamental taxonomic information caused by taxonomic impediments, there are challenges in unveiling and developing hymenopteran biological control agents. Braconidae, the second-largest family in Hymenoptera, comprises approximately 25,000 species described and recorded. All known braconids attack only insect hosts, with many members exhibiting high host specificity. Leveraging their unique biology, many braconid species have been tested in biological control research, and some have been developed as commercial products. To create a synergistic effect between biological control and taxonomic research and to discover effective biological control agents, several collaborative research projects have been conducted. In this presentation, these collaborative research projects will highlight the critical role of bridging taxonomic knowledge and biological control expertise, offering potential solutions for more effective and sustainable pest management practices in agriculture.
        75.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: A decrease in physical activity has been observed due to the global pandemic, resulting in the onset and progression of musculoskeletal disorders as chronic diseases. Objectives: This study aimed to assess the difference in the degree of contraction of the lower limb muscles between the existing vertical vibration method and a new cross-vibration method. Design: Randomized controlled trial. Methods: The exercise program using whole-body vibration equipment was conducted for 12 sessions, 25 min per session, three times per week for 4 weeks. Results: The changes over time showed a significant difference in cross-alternating vibrations (P<.05), except for the lateral gastrocnemius and tibialis anterior, with no significant difference in sonic vertical vibration (P>.05). The interaction between time and group was significant for all muscles (P<.05), except for the biceps femoris, with differences between before the program and at 2 and 4 weeks after the program revealed in the post-hoc analysis. Conclusion: Future studies should further evaluate the use of CAV exercise devices as auxiliary equipment in exercise by assessing different groups and variations in intensity.
        4,000원
        76.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates how native Korean speakers, who moved from Kyungsang province to Seoul, acquire /w/ retainment in Seoul Korean (SK). The specific objective is to examine how mobile speakers adopt the SK-like /w/ retainment and evaluate how linguistic and non-linguistic factors influence this acquisition. Furthermore, the study aims to establish whether having explicit awareness of the SK-like /w/ retainment is a prerequisite for acquiring it. The overall results suggest that most speakers have successfully adopted the SK-like /w/ retention, but there is noticeable diversity among speakers in terms of the extent to which they retain /w/. This variability can be linked to linguistic and non-linguistic factors, such as where /w/ appears in speech and individual attitudes towards SK. This research sheds light on the acquisition of /w/ retainment among native Korean speakers who have relocated from Kyungsang province to Seoul, highlighting the impact of linguistic and non-linguistic factors. It underscores the role of explicit awareness and reveals significant interspeaker variation in the adoption of SK-like /w/ retainment, contributing to our understanding of dialect acquisition dynamics.
        5,400원
        77.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Degenerative arthritis is a common joint disease that affects many elderly people and is typically diagnosed through radiography. However, the need for remote diagnosis is increasing because knee pain and walking disorders caused by degenerative arthritis make face-to-face treatment difficult. This study collects three-dimensional joint coordinates in real time using Azure Kinect DK and calculates 6 gait features through visualization and one-way ANOVA verification. The random forest classifier, trained with these characteristics, classified degenerative arthritis with an accuracy of 97.52%, and the model's basis for classification was identified through classification algorithm by features. Overall, this study not only compensated for the shortcomings of existing diagnostic methods, but also constructed a high-accuracy prediction model using statistically verified gait features and provided detailed prediction results.
        4,000원
        78.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tulsi (Ocimum sanctum), commonly known as Holy Basil is a revered herb with a rich history in traditional medicine systems, particularly in Southeast Asia. For its medicinal properties, Tulsi has been regarded as an “Elixir of Life” and has been used to treat various ailments. However, the comprehensive investigation of Tulsi extracts and their potential pharmacological benefits, specifically in relation to antioxidant activity remains limited. Hence, the objective of this study was to evaluate the antioxidant activity of Tulsi leaf and stem extract using various screening methods. We investigate the antioxidant activity exhibited by the extract using three different methods involved the utilization of the total polyphenol content assay, the ferric reducing power assay and 2, 2-diphenyl-1-14 picrylhydrazyl (DPPH) assays. The results revealed that the Tulsi leaf extract (TLE) exhibited significantly higher antioxidant activity when compared to the Tulsi stem extract (TSE) in all the performed assays. The higher content of phenolics in TLE may have contributed to its superior antioxidant activity. The HPLC (high performance liquid chromatography) analysis of TLE revealed the presence of eugenol, active compound for several therapeutic properties. These findings provide an understanding of the bioactive compounds present in Tulsi extracts and their potential antioxidant benefits.
        4,000원
        79.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Efficient gene editing technology is needed for successful knock-in. Homologous recombination (HR) is a major double-strand break repair pathway that can be utilized for accurately inserting foreign genes into the genome. HR occurs during the S/G2 phase, and the DNA mismatch repair (MMR) pathway is inextricably linked to HR to maintain HR fidelity. This study was conducted to investigate the effect of inhibiting MMR-related genes using CdCl2, an MMR-related gene inhibitor, on HR efficiency in HC11 cells. Methods: The mRNA and protein expression levels of MMR-related genes (Msh2, Msh3, Msh6, Mlh1, Pms2), the HR-related gene Rad51, and the NHEJ-related gene DNA Ligase IV were assessed in HC11 cells treated with 10 μM of CdCl2 for 48 hours. In addition, HC11 cells were transfected with a CRISPR/sgRNA expression vector and a knock-in vector targeting Exon3 of the mouse-beta casein locus, and treated with 10 μM cadmium for 48 hours. The knock-in efficiency was monitored through PCR. Results: The treatment of HC11 cells with a high-dose of CdCl2 decreased the mRNA expression of the HR-related gene Rad51 in HC11 cells. In addition, the inhibition of MMR-related genes through CdCl2 treatment did not lead to an increase in knock-in efficiency. Conclusions: The inhibition of MMR-related gene expression through high-dose CdCl2 treatment reduces the expression of the HR-related gene Rad51, which is active during recombination. Therefore, it was determined that CdCl2 is an inappropriate compound for improving HR efficiency.
        4,000원
        80.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        간 동적 조영검사에 사용하고 있는 VIBE 시퀀스의 고식적인 방법과 딥러닝 방법에 관한 선행된 연구가 부족하여 영상의 평가와 검사의 방향성 및 타당성을 제시하고자 한다. ACR 팬텀 실험은 30회 반복 실험하였고, 저 대조도 분해능 평가영역 에서 syngo.via View&Go를 이용하여 신호대잡음비와 대조대잡음비를 평가하였고, 공간분해능 평가영역에서 MATLAB 을 통해 신호강도의 높이와 반치폭으로 공간 분해능을 평가했다. 팬텀 실험을 기준으로 Matrix 352를 설정하여 30명의 환자 실험을 했다. 간 실질, 간 문맥, 내림 대동맥에서 대조대잡음비를 평가했고, 공간 분해능은 간 문맥, 내림 대동맥의 경계면을 평가했다. 결과 분석은 이원배치 분산 분석으로 진행하고, 사후 분석은 Duncan을 사용했다. 통계분석은 정량적 으로 p-value 0.05 미만으로 유의한 것으로 판단했다. 팬텀 실험의 신호대잡음비와 대조대잡음비 결과는 Matrix 416 이하에서 유의하였으며, 공간분해능 결과는 고식적인 방법 Matrix 352 이하, 딥러닝 방법 288 이하에서 평가할 수 없었 다. 환자 실험 결과는 신호대잡음비, 대조대잡음비, 공간분해능 모두 유의했다. 본 연구는 고식적인 방법보다 딥러닝 방법 이 영상은 더 향상되었고, 획득 시간은 평균 4초(22.4%)가 단축되었다. 딥러닝 방법에서 Matrix 352를 적용하였을 때 검사 시간의 감소로 재현성과 호흡에 의한 인공물 감소가 있었다. 이에 딥러닝 방법에서 Matrix size 적용의 방향성을 제시할 수 있었다.
        4,000원
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