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        검색결과 1,733

        1.
        2024.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Currently, off-site dose calculations for nuclear power plants are conducted using a computer program (K-DOSE 60). The program is developed based on the regulatory guidelines of the Korea Institute of Nuclear Safety (KINS), which is a domestic nuclear regulatory agency. In this study, a domestic application of the International Atomic Energy Agency (IAEA) TRS (Technical Reports Series)-472 methodology for 3H and 14C in liquid effluents was studied. The dose-evaluation methods adopted and the program configuration for dose evaluation are described based on 3H and 14C in the liquid-effluent-evaluation module of the computer program. The accuracy of the program is verified by comparing the program-calculated results with hand calculation values. Furthermore, a comparative evaluation with LADTAP II, which is a liquid-effluent-evaluation methodology developed by the U.S. NRC (Nuclear Regulatory Commission), is performed. The result confirms that the program-calculated results for the IAEA TRS-472 methodology are consistent with the hand calculation values. Meanwhile, the result of comparative evaluation with LADTAP II indicates different results depending on the methodology used.
        4,000원
        2.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 전 세계적인 경제 불확실성이 높아짐과 함께 미국 주도의 집중적 중국 견제 또한 심화되자 이미 제조업 중심의 성장이 한계에 다다른 중국은 새로운 돌파구를 찾을 수밖에 없게 되었다. 그 돌파구 가운데 하나가 문화산업의 집중적인 육성이었 고, 그것은 중국 정부의 여러 발표들을 통해 확인할 수 있었다. 이에 본 연구는 중국 의 문화와 문화산업에 대한 올바른 이해를 통해 시사점을 찾고자, 중국의 문화와 관 련 산업에 대한 인식 변화, 중국 문화산업의 주요 분류 및 특성, 정책의 주요 기조 등을 연구대상으로 하여 면밀히 분석하였다. 분석의 결과 얻은 가장 중요한 시사점 은, 중국 정부가 자신들이 원하는 경쟁력을 갖춘 문화산업의 안정적 성장이라는 목 표를 달성하기 위해서는, 문화 및 문화산업에 대한 정책의 방향을 현재의 규제와 통 제 중심의 정책으로부터, 자율적인 진흥 중심의 정책으로 적극적으로 전환해야만 한 다는 것이다.
        5,100원
        3.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 창의적 교실 환경이 자기 조절학습과 학습 효능감을 매개로 학업성취도에 미치는 영향을 확인하기 위한 목적에서 수행되었다. 이를 위해 한국아동패널의 14차 조사의 원시 자료를 활용하였고, 주요 변인에 관하여 누락 응답이 없는 593개 자료를 연구 대상으로 선정하여 SPSS 26.0 및 AMOS 26.0 프로그램을 활용하여 구조 방정식 모형으로 검증하 였다. 분석 결과, 중학생의 창의적 교실 환경 인식, 자기 조절학습, 학습 효능감, 학업성취도 간에는 모두 정적으로 유의미한 상관관계가 있었다. 또 창의적 교실 환경 인식과 학업성취도의 관계를 자기 조절학습과 학습 효능감이 유의하게 매개하는 것으로 나타났다. 즉, 중학생이 수업 시 교 실 환경을 더 창의적이라 인식할수록 자기 조절학습이 촉진되며 이는 학 습 효능감을 증진함으로써 결과적으로 학업성취도가 높아지도록 만들 수 있음이 확인되었다. 이를 토대로 한국의 공교육이 중학생의 학업성취도 증진을 위해 조성해야 할 교실 환경의 중요성 및 나아가야 할 방향에 대 해 제언하였다.
        5,500원
        4.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The conventional multi-scale modelling approach that predicts carbon nanotube (CNT) growth region in heterogeneous flame environment is computationally exhaustive. Thus, the present study is the first attempt to develop a zero-dimensional model based on existing multi-scale model where mixture fraction z and the stoichiometric mixture fraction zst are employed to correlate burner operating conditions and CNT growth region for diffusion flames. Baseline flame models for inverse and normal diffusion flames are first established with satisfactory validation of the flame temperature and growth region prediction at various operating conditions. Prior to developing the correlation, investigation on the effects of zst on CNT growth region is carried out for 17 flame conditions with zst of 0.05 to 0.31. The developed correlation indicates linear ( zlb=1.54zst +0.11) and quadratic ( zhb=zst(7-13zst )) models for the zlb and zhb corresponding to the low and high boundaries of mixture fraction, respectively, where both parameters dictate the range of CNT growth rate (GR) in the mixture fraction space. Based on the developed correlations, the CNT growth in mixture fraction space is optimum in the flame with medium-range zst conditions between 0.15 and 0.25. The stronger relationship between growth-region mixture-fraction (GRMF) and zst at the near field region close to the flame sheet compared to that of the far field region away from the flame sheet is due to the higher temperature gradient at the former region compared to that of the latter region. The developed models also reveal three distinct regions that are early expansion, optimum, and reduction of GRMF at varying zst.
        4,300원
        5.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we synthesized a reduced graphene oxide-manganese dioxide (rGO-MnO2) composite material using a one-step hydrothermal method and used it as a transducer layer in solid-state ion-selective electrodes (ISEs) for monitoring potassium and sodium ions in sweat. The rGO-MnO2 composite was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), revealing its unique surface morphology and crystalline structures. Electrochemical characterizations, including cyclic voltammetry (CV) and potential response testing, demonstrated the excellent performance of the rGO-MnO2 composite material as a transducer layer in ISEs. The fabricated electrodes displayed good linear responses to potassium and sodium ions, with a voltage response of 36.4 mV and 47.6 mV per unit concentration change, respectively. The electrodes also exhibited improved resistance to gas interference, such as O2, N2, and CO2. We utilized these ISEs to measure changes in potassium and sodium ion concentrations in sweat samples collected over nine days of exercise, demonstrating the practical application of the rGO-MnO2-based ISEs. This work highlights the potential of using graphene/metal oxide composites as solid contact materials in ISEs for cost-effective and stable ion sensing applications.
        4,000원
        6.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Currently, Japan is undertaking a nationwide project to measure and map radioactive contamination around Fukushima, as part of the efforts to restore normalcy following the nuclear accident. The Japan Atomic Energy Agency (JAEA) manages the Fukushima Environmental Safety Center, located approximately 20 km north of the Fukushima Daiichi nuclear power plant in Minamisōma City, Fukushima Prefecture. In collaboration with the JAEA, this study involved conducting comparison experiments and analyses with radiation detectors in high radiation environments, a challenging task in Korean environments. Environmental radiation surveys were conducted using three types of detectors: CZT, NaI(Tl), and LaBr3(Ce), across two contaminated areas. Dose rate values were converted using dose rate conversion factors for each detector type, and dose rate maps were subsequently created and compared. The detectors yielded similar results, demonstrating their feasibility and reliability in high radiation environments. The findings of this study are expected to be a crucial reference for enhancing the verification and supplementation of procedures and methods in future radiation measurements and mobile surveys in high-radiation environments, using these three types of radiation instruments.
        4,900원
        7.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 환경교육용 보드게임 개발에 관한 연구다. 이를 위해 문헌 고찰과 전문가 인터뷰를 실시하여 핵심 메커니즘과 용어를 도출하였다. 또한, 타당도와 신뢰도 검증을 위하여 델파이 조사를 진행하였다. 연구 결과 9개 항목에 대하여 합의가 이뤄졌으며, 이를 기반으로 ‘수풀로 메이커’ 프로토타입을 제작하고 플레이테스트 를 진행하였다. 그 결과, 환경에 대한 관심, 생태복원의 개념, 탄소 중립에 대한 이해를 보여, 연구의 초기 목 적을 달성한 것으로 나타났다. 본 연구로 인해 개발된‘수풀로 메이커’는 아동과 청소년의 환경교육 교재의 역할 뿐만 아니라, 환경에 대한 깊이 있는 이해를 견인하고, 더 나아가 실천양식 변화의 잠재성을 키우는 역 할에 기여할 수 있을 것으로 기대한다.
        4,200원
        8.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        집약적이고 장기적인 양식어업 활동은 많은 양의 유기물을 발생시켜 퇴적환경과 생태계를 악화시켜왔다. 정부에서는 양식어장 의 환경 보전과 관리를 위해서 어장관리법을 제정하였고 이를 근거로 2014년부터 어류 가두리 양식장에 대한 어장환경평가가 실시되었 다. 따라서 어장환경평가를 위해 국내 환경에 적합한 과학적이고 객관적인 평가방법의 개발이 필요하였다. 이를 위해 저서다모류 군집과 양식장의 주 오염원인 유기물의 관계를 이용한 저서생태계 건강도지수(BHI)를 개발하였고, 본 연구에서는 저서생태계 건강도지수의 개발 과정과 계산방법을 소개하고자 한다. 저서생태계 건강도지수는 국내 연안역과 양식장에서 출현한 225종의 다모류를 대상으로 퇴적물 내 총유기탄소량의 농도 구배와 종별 분포특성을 연관지어 4개의 그룹을 나누고, 각 그룹에 가중치를 부여하는 방식으로 계산된다. 저서생 태계 건강도지수를 이용하여 저서동물군집을 4개의 생태등급(Grade 1: Nomal, Grade 2: Slightly polluted, Grade 3: Moderately polluted, Grade 4: Heavily polluted)으로 나누었다. 개발된 지수를 현장에 적용한 결과, 기존의 평가방법인 다양도 지수나 국외에서 개발된 AMBI와 비교해 보 다 정확하고 계절의 영향을 적게 받아 우리나라 환경을 평가하기에 효과적인 것으로 판단된다. 또한 저서생태계 건강도지수를 사용하면 어장환경을 정량화된 수치에 따라 등급화 할 수 있어 양식장 환경관리에 효율적으로 활용할 수 있을 것이다.
        4,800원
        9.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 실제 자연의 숲과 인위적으로 통제가 가능한 디지털 환경에서의 가상현실(VR)을 활용한 가상 숲에서 의 체험이 피험자의 심리적 또는 생리적으로 미치는 치유효과를 알아보기 위하여 수행되었다. 이를 밝혀내기 위해 C대학 건강한 학부생 81명을 실험참가자로 2022. 9. 5~12. 9에 걸쳐 디지털 환경 내에서의 시각을 통한 산림자극 효과를 실험하였다. 실험은 디지털환경(2D, 3D)에서 숲 환경을 통한 시각적 산림자극의 심리적, 생리적 회복 효과를 평가하였다. 심리적 효과분석인 SRI(스트레스 반응척도)의 실험결과는 집단 간 차이가 통계적으로 유의한 것으로 나타났다. 심리적 스트레스 측정을 위한 SRI 실험 결과는 세 집단 중 Control 집단을 제외한 디지털 환경에서의 2D 집단은 사전과 사후 간 차이가 미미한 것으로 나타났다. 3D 집단에서는 사전보다 사후가 낮게 나타났다. 이 결과 산림을 기반으로 한 디지털 환경(2D, 3D)에서 시각을 통한 산림자극이 심리적 스트레스를 유의하게 감소시켜주는 효과가 있음을 확인하였다. 디지털환경 내에서 시각을 통한 산림자극이 EEG(뇌파)에 미치는 변화 분석 결과, 이완이나 안정화 때 활성화 되는 것으로 나타나는 알파파(RA)가 긴장이나 각성 때 발현되는 베타파(RB) 보다 활성화 되는 것으로 확인 되었다. 본 연구는 신체적 거동 불편 등 이동 제약으로 인하여 자연 숲 환경에서 체험을 할 수 없는 이용자들에게 디지털환경 내에서 가상현실(VR) 속 숲 환경을 구현하여 시각적 산림자극 체험 기회를 제공함으로서 심리적, 생리적 회복 환경을 만들어 주는데 사용 할 수 있을 것으로 사료된다. 이러한 연구 결과가 디지털 환경에서 산림치유에 대한 활용의 기반이 되길 기대하고, 가상현실(VR)을 이용한 프로그램이 산림치유 활동에 도움이 되기를 기대한다.
        4,200원
        10.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study is to evaluate environmental improvement effects of underground road project, as a case study of ‘Seobu’underground expressway project in Korea. METHODS : The environmental improvement effects of underground road construction were classified into tree sector in this study – air quality, noise, and thermal environment. To evaluate these effects, this study collected and divided environment dataset into before, during, and after ‘Seobu’underground expressway construction, and compared the change of values with entire city. In addition, the quantification method of environmental improvement effects was suggested based on the literature review. RESULTS : The result of this study indicates that there exist significant improvement effects of urban environment after the construction of ‘Seobu’underground expressway. Specifically, the concentration of particulate matters (PM10) and daytime/nighttime noise, and land surface temperature (LST) were improved along the expressway. In addition, the overall environmental benefit of ‘Seobu’ underground expressway was estimated to 1.15 billion won per year. CONCLUSIONS : To promote systematic and consistent underground road project, it is required to establish legislative system for evalauting and supporting urban improvement effects.
        4,000원
        11.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to perform a quantitative analysis of Forward Collision Warning and crash frequency using heavy vehicle driving data collected in expressway driving environments, and to classify the driving environments where Forward Collision Warnings of heavy vehicles occur for accident-prone areas and analyze their occurrence characteristics. METHODS : A bivariate Gaussian mixture model based on inter-vehicle distance gap and speed-acceleration parameters is used to classify the environment in which Forward Collision Warning occurs for heavy vehicles driving on expressways. For this analysis, Probe Vehicle Data of 80 large trucks collected by C-ITS devices of Korea Expressway Corporation from May to June 2022. Combined with accident information from the past five years, a detailed analysis of the classified driving environments is conducted. RESULTS : The results of the clustering analysis categorizes Forward Collision Warning environments into three groups: Group I (highdensity, high-speed), Group II (high-density, low-speed), and Group III (low-density, high-speed). It reveals a positive correlation between Forward Collision Warning frequency and accident rates at these points, with Group I prevailing. Road characteristics at sites with different accident incidences showed that on-ramps and toll gates had high occurrences of both accidents and warnings. Furthermore, acceleration deviation at high-accident sites was significant across all groups, with variable speed deviations noted for each warning group. CONCLUSIONS : The Forward Collision Warning of heavy vehicles on expressways is classified into three types depending on the driving environment, and the results of these environmental classifications can be used as a basis for building a road environment that reduces the risk of crashes for heavy vehicles.
        4,000원
        12.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to identify the thresholds at which various factors affecting traffic crashes lead to actual traffic crashes METHODS : To verify the thresholds, we created scenarios and ran simulations with a combination of factors that affect traffic crashes. Lateral offset and minimum TTC were used to evaluate whether an incident occurred. RESULTS : In the first scenario, the most significant factor affecting traffic crashes is curvature, and it was found that the smaller the curvature(200 meters or less), the greater the deviation from the lane. And in the second scenario, especially the passenger car scenario, no accidents occurred when the curvature was greater than 90 meters and the speed was 40 km/h or less. The smaller the curvature and the higher the speed, the more accidents occurred. Similarly, in the bus scenario, no accidents occurred when the curvature was 120 meters or more and the speed was 30 km/h or less. Also, accidents tended to occur when the curvature was smaller and the speed was higher. CONCLUSIONS : Through this study, we derived the thresholds of factors that influence traffic crashes. The results are expected to help design and operate roads in the future and contribute to reducing traffic crashes.
        4,000원
        13.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the effects of amino acid complex additives, such as protected vitamin C (VC) or detoxified sulfur (DS), on the growth and metabolism of Hanwoo cattle under high-temperature conditions. Accordingly, farms in Temperature-Humidity Index (THI) regions ranging from 78 to 89 for over 100 days were selected. The experimental groups were control, T1 (lysine + methionine + VC, 50 g/head/day), and T2 (lysine + methionine + DS, 50 g/head/day) with 70, 77, and 71 animals each. The range of the THI for 115 days was 78-89, and this occurred in most of the experiment days. The results showed that there was no significant difference in rectal temperature among the groups. The body weight increased to 786.4 and 809.0kg in the T1 and T2 groups, respectively, compared to the control group (p<0.05). Linoleic acid showed a high result of 2.01% in the T1 group compared to the control group (p<0.05). Unsaturated fatty acids were higher at 55.70 and 56.54% in the T1 and T2 groups, respectively, compared to the control group (p<0.05), and the omega 6/3 ratio was reduced to 20.10% (p<0.05). These findings indicate that T1 has a positive impact on growth, meat quality, and fatty acid composition compared to the control group. In conclusion, amino acid complex with VC improved the body weight of Hanwoo steers and the unsaturated fatty acids and essential amino acids of their meat; however, further research is needed to clarify this impact on carcass performance.
        4,800원
        14.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The number of snowfall and the amount of snowfall are gradually increasing, and due to the characteristics of Seoul, which has a lot of traffic, it is difficult to respond quickly with a snow removal method that relies on snow removal vehicles. Therefore, it is necessary to develop an IoT based eco-friendly snow removal system that can respond to unexpected heavy snow in winter. In this study, the low temperature operation and snow removal performance of the IoT road condition snow removal detector and the snow removal system using CNT and PCM are evaluated in the climatic environment chamber. METHODS : To make artificial snow, it consists of an climatic environment chamber that can simulate a low temperature environment and equipment that can supply compressed air and cold water. Depending on the usage characteristics of the climatic environment chamber, use an air-water type snow maker. In order to make artificial snow, wet temperature, which takes into account the actual air temperature and the amount of moisture in the air, acts as the most important variable and is suitable for making snow, below –1.5 ℃. The lower the water temperature, the easier it is to freeze, so the water source was continuously supplied at 0 ℃ to 4 ℃. One of the two different pipes is connected to the water tank to supply water, and the other pipe is connected to the compressor to supply high-pressure air. Water is dispersed by compressed air in the form of many small droplets. The sprayed microscopic water particles freeze quickly in the low temperature environmental climatic chamber air and naturally fall to the floor, forming snow. Based on the KS C IEC 60068-2-1 cold resistance test standard, an integrated environmental test procedure was prepared to apply to IoT-based snow removal systems and performance evaluation was performed accordingly. The IoT based eco-friendly snow removal system is needed to in winter, so visual check and inspect the operation at the climatic chamber before setting up it to the actual site. In addition, grid type equipment was manufactured for consistent and reliable snow removal performance evaluation under controlled environmental conditions. RESULTS : The IoT-based eco-friendly snow removal system normally carried out the task of acquiring data and images without damaging the appearance or freezing in a low temperature environment. It showed clear snow removal performance in areas where PCM and CNT heating technology were applied to the concrete slab. This experiment shows that normal snow removal tasks can be carried out in low temperature environments in winter. CONCLUSIONS : The integrated environmental test procedures and grid type evaluation equipment are applied to low temperature operation and snow removal performance evaluation of snow removal systems. In the climatic environment chamber, where low temperature environments can be simulated, artificial snow is created regardless of the season to derive quantitative experimental results on snow removal performance. PCM and CNT heating technology showed high snow removal performance. The system is expected to be applied to road site situations to preemptively respond to unexpected heavy snow in winter.
        4,000원
        15.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 공원별 유치거리를 기준으로 보행자가 도달할 수 있는 거리에 따른 서비스 면적 값을 통하여 공원별 접근성 분석을 하고자 한다. 공원별 서비스 면적 값의 도출을 위하여 첫째, 연령 계층의 분류와 보행속도 평균값을 도출하였다. 둘째, 전주시 도보 네트워크를 구축하였다. 셋째, 구축된 도보 네트워 크에 보행 저항요인 중 경사도와 보행 저항성 식을 입력하여 저항요인을 포함한 도보 네트워크를 구축 하였다. 위 데이터들을 기반으로 네트워크 분석을 통해 연령 계층별 속도를 고려한 서비스 면적, 보행 저항요인을 고려한 서비스 면적을 도출하였다. 형성된 서비스 면적간의 뚜렷한 값의 차이를 보여주기 위해 법정 유치거리에 의한 서비스 면적을 기준으로 비율로 수치화하여 비교하였다. 분석결과 보행 저항요인이 고려되지 않은 네트워크에서 청․장년층의 경우 유치거리에 의한 서비스 면적보다 최소 –4.1%, 최대 –53.4%의 감소율을 나타낸다. 고령층의 경우 보행 저항요인이 고려되지 않은 네트워크에 서 최소 –23.9%, 최대 –69.4%라는 큰 격차의 서비스 면적 감소율이 분석되었다. 또한 청·장년층과 고령 층 모두 저항요인이 고려된 네트워크에서 나타나는 서비스 면적은 저항요인을 고려하지 않았을 때 보 다 약 2~3%의 면적이 감소함을 보였다. 본 연구결과를 바탕으로 기존의 설정된 법정 유치거리는 연령 계층, 보행 저항요인 등 다양한 변수를 고려하지 않은 직선거리만의 평균값이며, 기존의 제도적 장치 를 지속해서 사용한다면 서비스 면적의 감소율은 연령 계층과 시간의 흐름에 따라 증가 할 것이다. 본 연구는 기존 산정된 법정 유치거리를 기준으로 연령계층과 보행 저항요인의 고려를 통해 유지되어 왔 던 제도적 장치가 변화가 필요하다는 점을 시각화하고 수치화 하는데 의의가 있다.
        4,000원
        16.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This research assesses the influence of emulsified asphalt on vegetation growth by examining parameters such as moisture content, temperature, pH, electrical conductivity, and analyzing the extent of green coverage using image analysis. METHODS : Within this study, sensors were employed to measure the growth environment of vegetation treated with emulsified asphalt. Furthermore, the analysis of the greening rate through image analysis has been incorporated. RESULTS : Research indicates that emulsified asphalt effectively secures seeds to surfaces and maintains moisture content for an extended period. However, the excessive utilization of emulsified asphalt has been observed to reduce germination and greening rates. CONCLUSIONS : The application of an optimal emulsified asphalt content is presumed to promote vegetation growth. To establish objective, it is imperative to conduct comprehensive research on its long-term structural effects regarding growth, greening rate, and slope when integrated with emulsified asphalt.
        4,000원
        17.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine seafood product quality change in the fresh food cold chain logistics. Salmon was stored in three different simulated refrigerated distribution environments according to door opening time (0, 20, and 60 s) every 10 min before the samples’ qualities were evaluated. The temperature inside the refrigerator generally rose from the bottom to the top, and it was possible to confirm the rapid change in temperature in the order of A, B, and C as the door opening time increased. It was observed that the freshness of salmon decreased as the door opening time increased through the evaluation of various food qualities of salmon, such as its appearance, color, pH, VBN, moisture content, hardness, general bacteria, and E. coli bacteria. It was confirmed that fresh food quality is strongly associated with delivery temperature, while cold-chain delivery vehicles must reduce heat exposure time during delivery.
        4,000원
        20.
        2023.11 구독 인증기관·개인회원 무료
        Bentonite, primarily composed of montmorillonite, plays a crucial role as one of the engineering barrier materials in a deep geological repository (DGR). The advantageous properties of montmorillonite, such as its swelling capacity, low permeability, and low thermal conductivity, make it a key component as a buffer material for isolating high-level radioactive waste from the surrounding natural environment. It has been known that the stability of montmorillonite is influenced by a wide range of pressure-temperature-composition (P-T-X) conditions relevant to the DGR environment. When considering potential geological events, of notable concerns are its interactions with groundwater or seawater at elevated temperatures, leading to safety hazards within the system. In this study, therefore, we investigated the hydration and dehydration reactions of Ca-montmorillonite with saline fluids such as NaCl and KCl solutions at elevated pressures and temperatures by conducting in-situ X-ray diffraction experiments using both a capillary sample heating cell and a resistive-heated diamond anvil cell. As a result, we observed different hydration states of montmorillonite depending on the chemical composition of fluids, i.e., tri-hydrated layers in NaCl and bi-hydrated layers in KCl solutions, respectively. Furthermore, we identified that montmorillonite undergoes distinct stepwise dehydration with increasing temperature, and the dehydration temperature of montmorillonite significantly increases with increasing water pressure. Consequently, this study would provide insights into the stability of hydrated montmorillonite in a seawater-dominated fluid environment and its implications for the long-term safety of the disposal system.
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