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        검색결과 452

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Exploring highly efficient, and low-cost oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts is extremely vital for the commercial application of advanced energy storage and conversion devices. Herein, a series of graphene-like C2N supported TMx@C2N, (TM = Fe, Co, Ni, and Cu, x = 1, 2) single- and dual-atom catalysts are designed. Their catalytic performance is systematically evaluated by means of spin-polarized density functional theory (DFT) computations coupled with hydrogen electrode model. Regulating metal atom and pairs can widely tune the catalytic performance. The most promising ORR/OER bifunctional activity can be realized on Cu2@ C2N with lowest overpotential of 0.46 and 0.38 V for ORR and OER, respectively. Ni2@ C2N and Ni@C2N can also exhibit good bifunctional activity through effectively balancing the adsorption strength of intermediates. The correlation of reaction overpotential with adsorption free energy is well established to track the activity and reveal the activity origin, indicating that catalytic activity is intrinsically governed by the adsorption strength of reaction intermediates. The key to achieve high catalytic activity is to effectively balance the adsorption of multiple reactive intermediates by means of the synergetic effect of suitably screened bimetal atoms. Our results also demonstrate that lattice strain can effectively regulate the adsorption free energies of reaction intermediates, regarding it as an efficient strategy to tune ORR/OER activity. This study could provide a significant guidance for the discovery and design of highly active noble-metal-free carbon-based ORR/OER catalysts.
        5,100원
        2.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 본 연구의 목적은 체계적 고찰 과정을 통해 기존에 발표된 지역사회 연하장애 평가도구 현황 및 특성을 확인하여 지역사회 연하재활치료 현장에서 활용 가능한 이론적 기초를 제공하는 것이다. 연구방법: Pubmed, ProQeust, Embase, Research Information Sharing Service (RISS)의 원문제공 서비스를 이용하여 2011년에서 2023년에 투고된 논문을 대상으로 지역사회, 판별, 평가, 검사, 노인, 치매 등의 주요 검색어를 활용하여 검색하였다. 총 40개 논문에서 13개의 연하재활 평가 도구의 구성 및 특성을 분석하였다. 결과: 지역사회 환경에서 사용된 질문 형태의 연하재활 평가도구는 총 13개였으며 지역사회 노인을 대상으로 개발된 평가도구는 6개였다. 도구의 질 확인에서 대부분 보통에서 높은 수준으로 확인되었다. 문항 분석을 통해 확인한 결과 총 14영역을 평가하는 것으로 조사되었으며, 내용은 삼킴 관련 3영역(삼킴 기능, 안전한 삼킴, 삼킴 정도), 음식 관련 2영역(음식 처리, 음식), 식사 시간, 침흘림, 삶의 질, 감정, 영양, 구강 건강, 감각, 자세, 기타였다. 기타에는 역류와 음성 변화, 인지 능력, 신체 능력, 사회적지지가 포함되었다. 적게는 1영역만 평가하는 도구도 있었으나 대부분 3~9개 영역으로 종합적으로 평가하도록 구성되어 있었다. 결론: 연하장애 관리 및 치료는 기존 의료환경 접근 뿐 아니라 지역사회에서의 종합적인 관리 역시 중요하다. 본 연구 결과가 지역사회 연하재활 전문가의 연하장애 평가 선택 및 임상 활용에 도움이 되기를 기대한다.
        5,400원
        4.
        2024.04 구독 인증기관·개인회원 무료
        The major innate immune pathways in Asian longhorned ticks, Haemaphysalis longicornis, include Toll, IMD, and JAK/STAT. In the field, H. longicornis can be infected with various pathogens including Severe Fever with Thrombocytopenia Syndrome Virus (SFTS virus), Rickettsia, Babesia and Anaplasma species. One approach to identify whether ticks are infected with pathogens is by examining the expression levels of immune response genes. To evaluate whether upregulation of immune genes from H. longicornis can serve as an indicator for pathogen infection in ticks, we first designed primer sets for Dorsal, STAT, and Relish from the H. longicornis genome. We then conducted quantitative reverse transcription PCR(qRT-PCR) on cDNA of field-collected H. longicornis and identified individuals with high expression levels in immune response genes. Subsequently, we performed digital PCR assays to determine whether selected ticks were infected with SFTS virus. Using this approach, we evaluated correlation between pathogen infection and upregulation of immune response genes in ticks. Although more experiments are needed to draw conclusions, this study suggests immune response gene-based screening methods for pathogen infected ticks from the field.
        5.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Clover cyst nematode (Heterodera trifolii, CCN) is one of the important plantparasitic nematodes in the Republic of Korea, causing serious damage to Kimchi-cabbage in Gangwon province since 2017. Soil fumigants are the preferred choice for managing CCN. However, cabbage fields in Gangwon province have a slope, making it challenging to apply soil fumigants and use plastic mulch. Consequently, alternative materials should be developed for managing CCN. Nematicidal cover crops and resistant cultivars are among the alternatives. We conducted resistance screening of 82 white mustard (Sinapis alba) resources from a genebank at RDA against CCN for use as nematicidal cover crops or breeding materials. In the first assay (1st, 2nd, and 3rd pot experiments), 15 white mustard resources were selected, while others were susceptible to CCN. To confirm the reproducibility of resistance to CCN for 13 selected resources, the second assay was performed. As a result, five white mustard resource (IT297309, IT297312, IT302951, IT302953, IT302954) demonstrated resistance to CCN. These findings indicate the potential use of these five white mustard resources as nematicidal cover crops or for breeding cultivars of Kimchi-cabbage in Republic of Korea.
        4,000원
        6.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 기저 스크리닝 기반 크리깅 모델(BSKM: Basis Screening based Kriging Model) 생성의 정확도를 높이기 위해 페널티 를 적용한 최대 우도 평가 방법(PMLE : Penalized Maximum Likelihood Estimation)에 대해서 소개한다. BSKM에서 사용하는 기저함 수의 최대 차수와 종류는 그 중요도에 따라서 결정하게 되며, 이때 중요도의 지표는 기저함수에 대한 교차 검증 오차(CVE : Cross Validation Error)로 택한다. 크리깅 모델(KM : Kriging Model) 구성시 최적의 기저함수 조합은 우선 최대 기저함수 차수를 선택하고 개별 기저함수의 중요도를 평가를 하게 된다. 최적 기저함수 조합은 크리깅 모델의 CVE가 최소가 될 때까지 개별 기저함수의 중요도 가 높은 순으로 기저함수를 하나씩 추가하며 찾는다. 이 과정에서 KM은 반복적으로 생성해야 하며, 동시에 데이터 사이의 상관관계 를 나타내는 하이퍼 매개변수(Hyper-parameters)도 최대 우도 평가방법을 통해 계산하여야 한다. 하이퍼 매개변수의 값에 따라 선택 되는 최적의 기저함수 조합이 달라지기 때문에 KM의 정확도에 막대한 영향을 미치게 된다. 정확한 하이퍼 매개변수를 계산하기 위해 서 PMLE 방법을 적용하였으며, Branin-Hoo 함수 문제에 적용하여 BSKM 의 정확성이 개선될 수 있음을 확인하였다.
        4,000원
        8.
        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
        9.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구는 인지선별검사(Cognitive Impairment Screening Test; CIST)에 대한 신뢰도 및 타당 도를 조사고하자 한다. 연구방법 : 본 연구는 서울시에 거주하는 일반인 대상으로 CIST에 응답한 321명의 자료를 사용하였다. 총 321명이 응답 완료한 CIST 자료를 활용하여 신뢰도 분석을 위한 첫 번째 단계로 확인적 요인분석을 통해 일차원성 및 지역 독립성(local independence)의 가정을 조사하였다. 두 번째로, 일차원성 및 지역 독립성의 가정을 완료한 항목을 통해 라쉬 모형 중 부분점수모형(Partial Credit Model; PCM)을 적용 하여 항목 적합도, 항목 난이도 계층적 구조를 조사하였다. 마지막으로. 항목 간에 개인 특성으로 인한 차이를 분석하기 위해 차등항목기능을 조사하였다. 결과: 대상자의 평균 연령은 80.48세(SD = 6.59)였으며, 남성이 45명(14.02%), 여성이 276명(85.98%)이었다. 본 연구의 신뢰도 분석 첫 번째 단계로 진행한 CIST의 확인적 요인분석 결과, 일차원성과 지역 독립성 가정을 모두 충족 하였다. 두 번째로 진행한 라쉬 분석을 통해 분석된 항목 적합도는 6개 영역 모두 적합(0.6 < MnSq < 1.4, -2.0 < ZSTD < 2.0)하였으며, 가장 쉬운 항목은 지남력, 가장 어려운 항목은 집행기능으로 나타났다. 세 번째로, 성별에서 차등항목기능이 주의집중력 항목에서만 있는 것으로 조사되었다. 결론 : 본 연구에서는 신뢰도를 분석하여 CIST가 지역사회 노인을 대상으로 시행할 수 있는 인지선별검사 도구로 적절한 평가도구임을 확인하였다. 따라서 본 연구 결과를 통해 CIST를 사용하는 연구자 및 임상 가들에게 도움이 될 것으로 사료된다.
        4,500원
        11.
        2023.05 구독 인증기관·개인회원 무료
        As a result of various generation, transmutation, and decay schemes, a wide variety of radionuclides exist in the reactor prior to accident occurrence. Considering all of the radionuclides as the accident source term in an offsite consequence analysis will inevitably take up excessive computer resources and time. Calculation time can be reduced with minimal impact on the accuracy of the results by considering only the nuclides that have a significant effect on the calculation among the potential radioactive sources that may be released into the environment. In earlier studies related to offsite consequence analysis, it is shown that the principal criteria for the radionuclide screening applied are as follows; radionuclide inventory in the reactor, radioactive half-life, radionuclide release fraction to the environment, relative dose contribution of nuclides within a specific group, and radiobiological importance. As a result, it is confirmed that 54, 60, and 69 nuclides are applied to the risk assessment performed in WASH-1400, NUREG-1150, and SOARCA (State-of-the-Art Reactor Consequence Analyses) project in the United States, respectively. In addition, in this study, the technical consultations with domestic and foreign experts were carried out to confirm details on criteria and process for screening out radionuclides in offsite consequence analysis. In this paper, based on the literature survey and technical consulting, we derived the screening process of selecting a list of radionuclides to be considered in the offsite consequence analysis. The first step is to eliminate radionuclides with little core inventory (less than specific threshold) or very short half-lives. However, important decay products of radionuclides that have short half-lives should not be excluded by this process. The next step is to further eliminate radionuclides by considering contribution to offsite impact, which is defined as a product of radioactivity released to the environment (i.e. ‘inventory in the reactor’ times ‘release fraction to offsite’) and comprehensive dose (or risk) coefficient taking into account all exposure pathways to be included. The final step is to delete isotopes that contribute less than certain threshold to any important dose metric through additional computer runs for each important source term. Even though it is presumed that this process is applicable to existing light water reactors and the set of accidents that would be considered in PSA, some of the assumptions or specific recommendations may need to be reconsidered for other reactor types or set of accident categories.
        12.
        2023.05 구독 인증기관·개인회원 무료
        This study presents a methodology to determine the radionuclides of concern that are expected to be found during the final status survey of Kori Unit 1 decommissioning. The methodology involved reflecting the evaluation results of ORIGEN based on reference documents such as NUREG/CR-3474, NUREG/CR-4289, NUREG/CR-0130, WINCO-1191, and representative fuel loading. A list of potential radionuclides of concern was provided by reflecting the list of radionuclides of concern included in the Kori Unit 1 decommissioning plan. To select the radionuclides of concern, we analyzed the approach of US decommissioning plants based on the recommendations of NUREG-1757 Vol.2 Rev.1 and excluded certain radionuclides from the list. The final list of 23 radionuclides of concern was derived by excluding radionuclides that have a short half-life, low specific activity, analytically difficult to measure, inert gases, or naturally occurring radionuclides. This methodology can be applied to other nuclear power plants, such as the Wolsong Nuclear Power Plant, by reflecting the unique characteristics of the reactor.
        18.
        2022.10 구독 인증기관·개인회원 무료
        Considering the Fukushima nuclear accident and the marine discharge plan of contaminated (or treated) water, it is necessary a seafood monitoring system for radioactive material screening. Currently, radioactivity tests in seafood are conducting in Korea. Although current method using a HPGe detector can provide very low uncertainty in determining radioactivity, there is a limitation in that rapid inspection cannot be performed because of a time-consuming pretreatment process as well as long measurement time (typically 10,000 s). To overcome this limitation, we are developing an insitu inspection device, a kind of screening system, which can monitor the radioactivity in seafood in a near real-time basis. In this study, the actual seafood with a check source was measured to verify the reliability of the Monte Carlo simulation model. The detector used in the experiment was a 5-cm-thick polyvinyl toluene (PVT) plastic scintillator with a 0.5-cm-thick lead shield for background reduction. A Cs-137 check source was placed within seafood. The seafood used in the experiment was fishcake, raw oyster, and dried laver, which is the representative seafood of fish, shellfish, and seaweed. These three seafood products of the same size and shape as the manufacturing process were used to predict the performance realistically. We compared the energy spectrum of the Cs-137 check source obtained from measurements and simulations. The region of interest (ROI) around the Compton edge was set to reduce the influence of the background and electronic noise. The results showed that the measured and simulated spectrum were in good agreement.
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