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        검색결과 17

        1.
        2023.11 구독 인증기관·개인회원 무료
        The safety of deep geological disposal systems has to be ensured to guarantee the isolation of radionuclides from human and related environments for over a million years. Over such a long timeframe, disposal systems can be influenced by climate change, leading to significant long-term impacts on the hydrogeological condition, including changes in temperature, precipitation and sea levels. These changes can affect groundwater flow, alter geochemical conditions, and directly/ indirectly impact the stability of the repository. Hence, it is essential to conduct a safety assessment that considers the long-term evolution induced by climate change. In this context, the Korea Atomic Energy Research Institute (KAERI) is developing the Adaptive Process-based total system performance assessment framework for a geological disposal system (APro). Currently, numerical modules for APro are under development to account for the longterm evolution that can influence groundwater flow and radionuclide transport in the far-field of the disposal system. This study focuses on the development of two numerical modules designed to model permafrost formation and buoyance force due to relative density changes. Permafrost is defined as a ground in which temperature remains below zero-isotherm (0°C) continuously for more than two consecutive years. In regions where permafrost forms, the relative permeability of porous media is significantly reduced. The changes in permeability due to permafrost formation are modelled by calculating the unfrozen fluid content within a porous medium. Meanwhile, buoyancy force can occur when there is a difference in density at the boundary of two distinct water groups, such as seawater (salt water) and freshwater. Sea level change associated with climate change can alter the boundary between seawater and freshwater, resulting in changes in groundwater flow. The buoyancy force due to relative density is modelled by adjusting concentration boundary conditions. Using the developed numerical modules, we evaluated the long-term evolution’s effects by analyzing radionuclide transport in the far-field of the disposal system. Incorporating permafrost and buoyancy force modelling into the APro framework will contribute valuable insights into the complex interactions between geological and climatic factors, enhancing our ability to ensure the secure isolation of radionuclides for extended periods.
        2.
        2023.05 구독 인증기관·개인회원 무료
        With the increasing demand for a repository to safely dispose of high-level radioactive waste (HLW), it is imperative to conduct a safety assessment for HLW disposal facilities for ensuring the permanent isolation of radionuclides. For this purpose, the Korea Atomic Energy Research Institute (KAERI) is currently developing the Adaptive Process-based total system performance assessment framework for a geological disposal system (APro). A far-field module, which specifically focuses on fluid flow and radionuclide transport in the host rock, is one of several modules comprising APro. In Korea, crystalline rock is considered the host rock for deep geological disposal facilities due to its high thermal conductivity and extremely low permeability. However, the presence of complex fracture system in crystalline rock poses a significant challenge for managing fluid flow and nuclide transport. To address this challenge, KAERI is participating in DECOVALEX-2023 Task F1, which seeks to compare and verify modeling results using various levels of performance assessment models developed by each country for reference disposal systems. Through the benchmark problems suggested by DECOVALEX-2023 Task F1, KAERI adopts the Discrete Fracture-Matrix (DFM) as the primary fracture modeling approach. In this study, the transport processes of reactive tracers in fractured rock, modeled with DFM, are simulated. Specifically, three different tracers (conservative, decaying, adsorbing) are introduced through the fracture under identical injecting conditions. Thereafter, the breakthrough curves of each tracer are compared to observe the impact of reactive tracers on nuclide transport. The results of this study will contribute to a better understanding of nuclide behavior in subsurface fractured rock under various conditions.
        3.
        2022.10 구독 인증기관·개인회원 무료
        In the geological disposal system whose host rock is crystalline rock, fractures play a significant role in the safety assessment as they are the main pathway of the radionuclide migration. From the perspective of long-term safety assessment, the properties of fractures can be changed by tectonic movement such as earthquake, uplift, etc. In general, methods for simulating fractures include Discrete Fracture Network (DFN), which directly simulates the fracture surface, and Equivalent Continuous Porous Media (ECPM), which is equivalent to the ratio of the fractures in a certain rock volume. DFN is generally appropriate for deterministic fractures with large scale and high flow velocity, but ECPM may be more appropriate for small scale and sporadically distributed stochastic fractures because the flow velocity is slow and thus the rock matrix diffusion needs to be considered. In fact, several commercial software, such as FracMan, are already in use to convert DFN to ECPM. However, in order to consider the change in properties of fractures due to tectonic movement in the long-term safety assessment, a model that converts DFN to ECPM needs to be modularized and embedded into the safety assessment model. In this study, therefore, an in-house MATLAB code was developed to convert DFN to ECPM, which can be used as a submodule. The algorithm of converting from DFN to ECPM basically followed the Oda’s method. As the first step of the algorithm, in order to obtain the volume ratio of the fracture in a certain mesh element, the cross-sectional area of the fracture and the mesh element was calculated. Then, porosities of each mesh element were calculated as the volume fraction of fractures passing through the mesh element. Based on the Oda’s method, the permeability tensors of each mesh element were calculated by using an empirical fracture tensor which is weighted by the cross-sectional area and transmissivity of each fracture. Finally, the newly developed module was verified by a benchmark test, in which the ECPM results converted from a certain DFN data by using the numerical module developed in this study were compared with those by using FracMan. The newly developed module will be installed in the process-based total system performance assessment framework (APro) being developed by KAERI.
        4.
        2022.10 구독 인증기관·개인회원 무료
        With the increase of temporarily-stored radioactive waste in Korea, the disposal of radioactive waste in a deep geological repository, which is located in crystalline rock at a depth of hundreds of meters below the ground level, has received great attention nowadays. To ensure the permanent isolation of radionuclides from the human and surrounding ecosystems, the safety assessment for the high-level radioactive waste disposal facilities is essential. For the reliable safety assessment of fractured rock, it is especially important to input proper hydraulic properties of fractures such as aperture and hydraulic conductivity, which can directly affect the fluid flow and radionuclide transport. Meanwhile, it has become important to consider sudden fault behavior caused by an earthquake with the recent occurrence of high-intensity earthquakes in the Korean Peninsula. The sudden fault behavior can induce the changes of the hydraulic properties of fractures. Since the changes of the hydraulic properties directly affects to the radionuclide transport in the fractured rock, it is important to estimate the effect of earthquake-induced stress change on hydraulic properties of fractures in the perspective of long-term safety assessment. In this study, the effect of an earthquake on the hydraulic properties of fractures was explored by a numerical approach. The static Coulomb stress change after the earthquake was calculated using software ‘Coulomb 3’ developed by United States Geological Survey (USGS) with the assumption for several mechanical properties such as Young’s modulus, Poisson’s ratio and effective coefficient of friction. The final stress after earthquake occurrence was calculated as the sum of the initial stress and the stress change. Thereafter, the normalized transmissivity of fracture after the earthquake was calculated using the final stress from the stress-transmissivity relationship. Using the methodology for calculating fracture transmissivity change induced by the earthquake developed in this study, the effect of several factors, such as the earthquake magnitude and the distance between fracture and epicenter, was additionally explored. The newly developed methodology will be applied to the processbased total system performance assessment framework (APro) being developed by KAERI, and this study is expected to be helpful for the safety assessment considering long-term evolution phenomena including earthquakes.
        5.
        2022.05 구독 인증기관·개인회원 무료
        With the increase of temporarily-stored spent radioactive fuels, there is an increasing necessity for the safe disposal of high-level radioactive waste (HLW). Among various methods for the disposal of HLW, a deep geological disposal system is adapted as a HLW disposal strategy in many countries. Before the construction of a repository in deep geological condition, a performance assessment, which means the use of numerical models to simulate the long-term behavior of a multi-barrier system in HLW repository, has been widely performed to ensure the isolation of radionuclides from human and related environments for more than a million years. Meanwhile, Korea Atomic Energy Research Institute (KAERI) is developing a process-based total system performance assessment framework for a geological disposal system (APro). To improve the reliability of APro, KAERI is participating in DECOVALEX-2023 Task F, which is the international joint program for the comparison of the models and methods used in deep geological performance assessment. As a final goal of Task F, the reference case for a generic repository in fractured crystalline rock is described. The three-dimensional generic repository is located in a domain of 5 km in length, 2 km in width, and 1 km in depth, and contains an engineering barrier system with 2,500 deposition holes in fractured crystalline rock. In this study, a numerical simulation of the reference case is performed with COMSOL Multiphysics as a part of Task F. The fractured crystalline rock is described with the discrete fracture matrix (DFM) model, which expresses major deterministic fractures explicitly in the domain and minor stochastic fractures implicitly with upscaled quantities. As an output of the numerical simulation, fluid flow at steady-state and radionuclide transport are evaluated for ~106 years. The result shows that fractures dominate the transport of radionuclides due to much higher hydraulic properties than rock matrix. The numerical modeling approaches used in this study are expected to provide a basis for performance assessment of nuclear waste disposal repository located in fractured crystalline rock.
        7.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A 2-year-old female Maltese dog was presented with a history of anemia and vaginal hemorrhagic discharge. Physical examination revealed severe vaginal hemorrhagic discharge, abdominal pain, pale mucous membranes, low blood pressure and dehydration. Results of serum biochemistry, hematology, venous blood gas, and electrolyte canine C-reactive protein (CRP) test revealed severe normocytic normochromic anemia, severe neutropenia, a high level of CRP, hypoglycemia, and imbalanced electrolytes. Abdominal ultrasound examination showed focal hypoechoic defect with loss of layering in uterine horn wall. A laparotomy revealed a clear reddish fluid in the abdomen, the fistula of left and right uterine horn, the purulent discharge from fistula, and symptoms of septic peritonitis near by the fistula site. The bitch underwent ovariohysterectomy and recovered without complication. Histopathological diagnosis of the uterine fistula site was adenocarcinoma.
        4,000원
        8.
        2017.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Adhesive capsulitis of the shoulder is a common cause of pain that occurs during shoulder movement, thereby restricting shoulder rotation in clinical practice. Although most patients respond to pain relief treatment (NSAID or corticosteroids) by improving their range of motion, it remains poorly understood without any definitive treatment algorithm. In addition to immune cells, synoviocytes, chondrocytes and osteoblasts in the joint are known to produce pro-inflammatory mediators such as reactive oxygen species (ROS), inflammatory cytokines and lipid mediators, presumably contributing to the pathogenesis of osteoarthritis (OA) and adhesive capsulitis. Although inflammation and also fibrosis are proposed to be the basic pathological changes of a frozen shoulder, there is a lack of information regarding the downstream targets of the pro-inflammatory ROS signaling pathway in the synoviocytes and also how these ROS targets are modulated at the transcription level by a corticosteroid - dexamethasone. In this study, we used human fibroblast like synoviocytes (HFLS) to characterize the signaling targets of ROS by employing a human DNA microarray tool and studied the role of dexamethasone in this process. Our data suggest that several genes such as FOS, FOSB and NFkBIZ, which are known to be involved in pro- or anti- inflammation response, are modulated at the transcription level by ROS and dexamethasone.
        4,000원
        9.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        사료이용 측면에서 유지 및 성장에 필요한 섭취량과 체내에 이용되지 않은 섭취량으로 구분할 수 있 으며, 체내에 이용되지 않은 섭취량을 잔류사료섭취량(Residual Feed Intake; RFI)이라 한다. 본 실험 은 국내 종돈의 RFI 유전모수를 추정하기 위해 2001년부터 2014년까지 태어난 Duroc종 8,696두의 검 정자료를 활용하였다. 일당증체량과 RFI의 육종가 상관관계는 -0.2로 음의 상관으로 조사되었는데 (P>0.01), RFI를 낮추면 일당증체량 개량에도 긍정적인 영향을 줄 수 있는 것으로 사료된다. 회귀추정 방식에 따른 RFI1(일당증체량)과 RFI2(일당증체량, 등지방두께)의 유전력은 각각 0.37, 0.45로 고도의 유전력을 나타내었다. 향후 국내에서도 개체단위 사료섭취량 측정으로 추정된 RFI를 개량에 활용한다면 농가 수익 개선에 많은 도움을 줄 수 있을 것으로 판단된다.
        4,000원
        10.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A 10-year-old spayed female Yorkshire Terrier visited for a physical checkup. The bitch had a history of ovariohysterectomy for treatment of pyometra a year ago. On physical examination, the dog was bright and alert. Complete blood counts, serum biochemistry and blood gas analysis results did not show any deviations within normal ranges. Radiographic and ultrasonographic examinations revealed unilateral hydronephrosis and hydroureter of the right kidney and ureter, and obstruction of the distal ureter was observed. On the basis of these results, nephroureterectomy was performed. During the operation, the adhesion of the distal ureter and surrounding tissue cells were observed without the evidence of the ureteral ligation. The distal ureteral obstruction was presumed to be adhesion caused by fibrous tissue formation between ureter and retained broad ligament, or incompletely removed blood clots following ovariohysterectomy. This case report describes the occurrence of hydroureteronephrosis caused by adhesion of the distal ureter following ovariohysterectomy in a bitch.
        3,000원
        11.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study is to examine current status of swine AI and boar stud in South Korea using survey and data analysis. This survey included 48 boar studs registered as ‘semen processing business’. The survey data were collected by direct visitation, FAX and/or telephone conversation for 7 months from June through December in 2013. 48 boar studs owned a total of 3,537 boars and the Duroc breed accounted for the highest rate (75.3%) of all boar breeds. In case of ownership, agricultural management corporations was the highest (50.0%) and followed by individual ownership (33.3%). Large-scale boar studs in terms of own over 151 boar were surveyed as 4.2% and most boar studs owned less than 100 boars (77.1%). The amount of liquid semen provided by 48 boar studs were 1,889,000 doses and each boar stud provided average of 39,000 does, which is represented for 90% consumption by sows in South Korea.
        4,000원
        12.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cryopreservation of boar semen is continually researched in reproductive technologies and genetic resource banking in breed conservation. For evaluating the boar semen quality, sperm motility (MOT) is an important parameter because the movement of spermatozoa indicates active metabolism, membrane integrity and fertilizing capacity. Various researches have been trying to improve the quality of semen post-thawed in boar. Recently, polymorphism (g.358A>T) of cluster-of-differentiation antigen 9 (CD9) gene reported to be significant association with MOT. Also, CD9 gene was expressed in the male germ line stem cells is crucial for sperm-egg fusion, and was therefore selected as candidate gene for boar semen. This study was conducted to evaluate the pig SNP (g.358A>T) of CD9 gene as a positional controlling for semen parameters of post-thawed boar semen. To results, the g.358A>T SNP of the CD9 gene was significantly associated with the traits such as MOT, curve linear velocity, straight line velocity, average path velocity and amplitude of lateral head displacement. Particularly, the g.358A>T SNP significantly has the highest association with MOT and animals with AA genotype (p<0.001). Therefore, we suggest that the g.358A>T in the intron 6 region of the porcine CD9 may be used as a molecular marker for Duroc boar Post-thawed semen quality, although its functional effect was not defined yet.
        4,000원
        14.
        2019.03 KCI 등재 서비스 종료(열람 제한)
        오미약성 이론은 다섯가지 맛 중에서 적어도 하나 이상을 맛을 포함하는 다양한 허브로 구성되어 있으며, 이러한 이론은 인간의 질병을 예방하고 면역 체계를 강화하는데 사용되어왔다. 본 연구의 목적은 오미약성 이론에 근거한 단일 추출물 및 혼합 추출물의 효능 차이와 성분 변화를 확인하는 것이다. 황련, 승마 및 백복령 세가지 약초를 선택하였고 단일 추출물 및 혼합 추출물의 약리학적 효능을 평가하였다. 결과적으로 혼합추출물은 단일추출물과 비교하여 400 ug/mL 농도에서 우수한 세포 이동 효과를 보였다. 또한 혼합 추출물은 수지상세포의 활성을 증가시켜 면역을 강화시켰으며 DPPH assay 및 HPLC-ABTS assay를 통해 가장 높은 항산화 활성을 보였다. 이번 연구에서 우리는 한의학적 이론을 접목하여 화장품 및 의약품 분야에 응용 가능한 새로운 소재를 개발하였다.
        15.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        This study was performed to evaluate the possibility of application of lactic acid bacteria fermentation to increase the anti-allergic activity of the extracts from Houttuynia cordata Thunb. H. cordata Thunb was fermented on 25, 30, 35 and 40℃ for 5 days by two species of lactic acid bacteria, Leuconostoc mesenteroides 4395 and Lactobacillus sakei 383. The anti-allergic activity of water extracts of H. cordata Thunb was then analyzed both before and after fermentation. Anti-allergic activity was determined in vitro assays by using 5-lipoxygenase (5-LO), cyclooxygenase-2 (COX-2) and β-hexoseaminidase release of RBL-2H3 cells (degranulation marker). The extracts fermented at 35℃ by both bacteria had the highest inhibitory activities against 5-LO, and also higher than the control, and the one fermented at 30℃ by both bacteria had the highest inhibitory activity against COX-2. The degranulation of RBL-2H3 cells induced by IgE-antigen complex was estimated as β-hexoseaminidase release rate as reference of 100%, the release rates were inhibited in 25 μg/ml of the extracts fermented at 30, 35 and 40℃ only by L. mesenteroides 4395. These results indicate that anti-allergic activity of H. cordata Thunb is increased by lactic acid bacteria fermentation.
        16.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        Purpose - This study analyzed the characteristics of social networking sites (SNSs) using related literatures, and researched the models discussed in precedent studies, to investigate the effects of SNS characteristics upon consumers’awareness, purchase intention, and recommendation. The purpose of the study was to investigate the use of SNSs as a marketing tool. Design, methodology, and approach - For an empirical analysis, the author distributed questionnaires online and offline, to verify the models and hypotheses. Respondents were persons aged 17 or older, who were frequent users of SNSs. The questionnaire survey was conducted for 11 days from September 30, 2013 to October 10, 2013. The author distributed 450 copies and received 430 responses. Finally, 412 copies were used for the analysis after excluding 18 copies having poor answers. Results – The findings about SNS users' behavior could be used as material in the future use of SNS as a marketing tool. Further, the study provided not only theories about SNS characteristics, but also variables and items that were verified during the empirical study. Conclusions – Further studies are needed to overcome the limitations and to establish various kinds of SNS marketing strategies in detail.
        17.
        1989.03 KCI 등재 서비스 종료(열람 제한)
        외국에서 도입한 32개의 서로 다른 Alfalfa 품종을 우리나라 기후풍토에서 재배하여 초장과 건물중 등의 생육상태를 비교 검사한 결과 가장 우수한 생육상태를 나타낸 품종들은 다음과 같다. 1. 초장생육이 우수하였던 상위 7개 품종들은 Diamond>Milkmaker> Arrow>Chalienger>Sapphire > Dekalb brand 135> LS-1920의 품종순이고 최하위 초장의 7개 품종을 하위순으로 열거하여 보면 Pioneer brand 5929> Maxidor> Dekalb brand 167> Pierce> Blazer> Raidor> Pioneer brand 532의 순이었다. 2. 건물중이 많은 상위 7개 품종은 Pike>LS-1920>Challenger>Salute>Diamond>Decathlon>Pioneer brand 581의 품종순이며 최하위 건물중의 7개 품종은 Maxidor>Pioneer brand 5929>Pioneer brand 532>Florida 77> Pierce> Magnum> Blazer의 순이었다. 3. 초장과 건물중의 결과를 비교하여 보면 대체로 초장에서 우수하였거나 열거하였던 품종들이 역시 건물중에서도 우세하거나 열거하여 서로가 비례하는 결과를 보였다. 4. 이상에서 조사한 바와 같이 가장 좋은 생육상태 및 수활량을 보인 품종들은 Pike, LS-1920, Challenger, Salute, Diamond 등이었으며 이들중 Challenger 품중을 제외한 나머지 품종들은 내한성이 중간정도인 Semi-dormant 계통으로 우리 나라 재배환경에 가장 적합할 것으로 생각된다.