검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 25

        1.
        2023.11 구독 인증기관·개인회원 무료
        In order to establish disposal plans for sludge, which is one of the untreated waste materials from domestic nuclear power plants, it is necessary to determine the radioactivity concentration of radioactive isotopes. In this study, we aim to evaluate the gross alpha radioactivity of sludge containing radioactive contaminants after pre-treatment, in order to assess the level of sludge waste and obtain analytical data for discussing disposal methods. Samples of sludge generated from nuclear power plants were pre-treated, solutionized, and prepared as analysis samples for evaluating the gross alpha radioactivity.
        2.
        2023.11 구독 인증기관·개인회원 무료
        Typically, the bottom of the effluent treatment facility at a nuclear power plant contains sediment, which is low-contamination waste consisting of sludge, gravel, sand, and other materials from which radioactive contaminants have been removed. Among these sediments, sludge is an irregular solid form consisting of small particles that are coagulated together, with radioactive isotopes containing cobalt attached. Currently, there is a record of disposing of dry active waste from domestic nuclear power plants, and efforts are underway to gather basic data for the disposal of untreated waste such as sludge, spent filter, and spent resin. In particular, the classification and disposal methods of waste will be determined based on the radioactivity concentration. Therefore, plans are being made to determine the radioactivity concentration of radioactive isotopes and establish disposal plans for sludge samples. In this study, pre-treatment and solutionization were carried out for the analysis of radioactive isotopes in sludge sampels from nuclear power plants. The deviation of the gamma radioisotope analysis results was derived to obtain an optimal sample quantity that represents the sludge.
        4.
        2023.05 구독 인증기관·개인회원 무료
        Domestic nuclear power plants developed the scaling factors for the radioactive waste generated from 2004 to 2008 for the first time. Afterwards, the effectiveness of continuous application of the scaling factors have been evaluated for newly generated radioactive waste over the past two years. It was confirmed that most of the initially developed scale factors were effective within a factor of 10 principle, which is an acceptable range. The scaling factors were updated using the analysis data base from 2004 to 2016. A scaling factor refers to the calculated abundance ratio between Key (Easy-to- Measure) and DTM (Difficult-to-Measure) nuclide at the time of generation of radioactive waste based on the source term in the reactor of an operating nuclear power plant. The effectiveness of continuous application of scaling factors can be evaluated at regular intervals regardless of operation status or when there are events that change scaling factors during nuclear power plant operation, such as zinc injection, large-scale facility replacement, and long-term shutdown etc. Even in the case of a permanently shut down nuclear power plant in which fuel is withdrawn from the reactor and generation of new nuclides by nuclear fission and radiation has stopped, periodic verification is conducted to confirm whether the scaling factor developed before permanent shutdown can be effectively applied to the radioactive waste generated after permanent shutdown. However, depending on the nuclear power plant decommissioning strategy or conditions, the period of permanent shutdown prior to decommissioning can be very long, so preparations are needed to ensure the appropriateness of scaling factor operation. In the case of domestic nuclear power plants, Kori Unit 1, a light water reactor, was permanently shut down in June 2017, and as a heavy water reactor nuclear power plant, the permanent shutdown of Wolseong Unit 1 was finally decided in December 2019 after twists and turns including large-scale facility replacement and long-term shutdown. In this paper, we have predicted when the scaling factors will change significantly due to radioactive decay and the difference in halflife between the Key and DTM nuclides over time after permanent shutdown. We also have tried to find appropriate countermeasures for the operation of scaling factors during permanent shutdown period, such as updating scaling factors or applying correction factors.
        5.
        2022.05 구독 인증기관·개인회원 무료
        In order to indirectly evaluate the inventory of difficult-to-measure (DTM) nuclides in radioactive waste, the scaling factor method by key nuclide has been used. It has been usually applied to low-and intermediate-level dry active waste (DAW), and the tolerance of 1,000% margin of error in the US, that is the factor of 10, is applied as an allowable confidence limits considering the inhomogeneity of the waste and the limitation of sample size. This is because the scaling factor method is based on economic efficiency. Confidence limits is the uncertainty (sampling error) according to predicting the mean value of the population by the mean value of the sample at 95% confidence level, reflecting the limitations of sample size (representation) with the standard deviation. If the standard deviation is large, the sample size can be increased to satisfy the allowable confidence limits. In the new nuclear power plants, the concentration of cesium nuclide (137Cs) in radioactive waste tends to be very low due to advances in nuclear fuel and reactor core management technology, which makes it very difficult to apply cesium as a key nuclide. In addition, it is inevitable to apply the mean activity concentration method, which reasonably and empirically derives the concentration of DTM nuclides regardless of key nuclide, when the correlation between key and DTM nuclides is not significant. The mean activity method is a methodology that applies the average concentration of a sample set to the entire population, and is similar to applying the average concentration ratio between key and DTM nuclides of a sample set to the population in the scaling factor method. Therefore, in this paper, the maximum acceptable uncertainty (confidence limits) at a reasonable level was studied when applying the mean activity concentration method by arithmetic mean unlike the scaling factor method which usually uses the geometric mean method. Several measures were proposed by applying mutatis mutandis the acceptable standard deviation in radiation measurement and the factor of 10 principle, etc., and the appropriateness was reviewed through case analysis.
        9.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근의 기후변화는 연안에서 더욱 가속화되고 있어 연안에서의 해양 환경변화 감시의 중요성이 커지고 있다. 클로로필-a 농도는 해양 환경 변화의 중요한 지표 중 하나로 수십년 동안 여러 해색 위성을 통해 전구 해양 표층의 클로 로필-a 농도가 산출되었으며 다양한 연구 분야에 활용되었다. 하지만 연안 해역의 탁한 해수는 외해의 맑은 해수와는 구별되는 구성 성분과 광학적 특성으로 인해 나타나는 심각한 오차 때문에 일반적으로 사용되는 전지구 대양을 위하여 만들어진 클로로필-a 농도 알고리즘은 연안 해역에 대입할 수 없다. 또한 연안 해역은 해역에 따라 성분과 특성이 크게 달라져 통일된 하나의 알고리즘을 제시하기 어렵다. 이러한 문제점을 극복하기 위하여 연안의 탁도가 높은 해역에서는 구성 성분과 광학적 변동 특성을 고려한 다양한 알고리즘들이 개발되어 사용되어 왔다. 클로로필-a 농도 산출 알고리즘은 크게 경험적 알고리즘, 반해석적 알고리즘, 기계학습을 활용한 알고리즘 등으로 나눌 수 있다. 해수의 반사 스펙트 럼에 기반한 청색-녹색 밴드 비율이 기본적인 형태로 주로 사용된다. 반면 탁한 해수를 위해 개발된 알고리즘은 연안 해역에 존재하는 용존 유기물과 부유물의 영향을 상쇄시키기 위한 방식으로 녹색-적색 밴드 비율, 적색-근적외 밴드 비 율, 고유한 광학적 특성 등을 사용한다. 탁한 해수에서의 신뢰성 있는 위성 클로로필-a 농도 산출은 미래의 연안 해역을 관리하고 연안 생태 변화를 감시하는데 필수적이다. 따라서 본 연구는 탁도가 높은 Case 2 해수에서 활용되어온 알고리즘들을 요약하고, 한반도 주변해역의 모니터링과 연구에 대한 문제점을 제시한다. 또한 다분광 및 초분광 센서의 개발로 더욱 정확하고 다양한 해색 환경을 이해할 수 있는 미래의 해색 위성에 대한 발전 전망도 제시한다.
        5,100원
        10.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since the Coastal Zone Color Scanner (CZCS)/Nimbus-7 was launched in 1978, a variety of studies have been conducted to retrieve ocean color variables from multi-satellites. Several algorithms and formulations have been suggested for estimating ocean color variables based on multi band data at different wavelengths. Chlorophyll-a (chl-a) concentration is one of the most important variables to understand low-level ecosystem in the ocean. To retrieve chl-a concentrations from the satellite observations, an appropriate algorithm depending on water properties is required for each satellite sensor. Most operational empirical algorithms in the global ocean have been developed based on the band-ratio approach, which has the disadvantage of being more adapted to the open ocean than to coastal areas. Alternative algorithms, including the semi-analytical approach, may complement the limits of band-ratio algorithms. As more sensors are planned by various space agencies to monitor the ocean surface, it is expected that continuous monitoring of oceanic ecosystems and environments should be conducted to contribute to the understanding of the oceanic biosphere and the impact of climate change. This study presents an overview of the past and present algorithms for the estimation of chl-a concentration based on multi-satellite data and also presents the prospects for ongoing and upcoming ocean color satellites.
        4,600원
        11.
        2018.11 구독 인증기관·개인회원 무료
        Alpha-linolenic acid (ALA; n-3 18:3), a one of omega-3 fatty acid, is mainly contained in chloroplast of plant and ALA is an essential fatty acid, not synthesized in mammalian body, it must be supplied from foods. Polyspermy is especially high on in vitro fertilization (IVF) in pigs, which is a major obstacle to in vitro embryo production systems. In our previous study, when ALA was supplemented during in vitro maturation (IVM), the methaphase-II rate and gluthathione level was increased. The objective of this study was to evaluate the effects of alpha-linolenic acid (ALA) supplementation during IVM and subsequent of IVF in pigs. The cumulus-oocyte complexes (COCs) were submitted to IVM medium containing 0, 25, 50, and 100 μM ALA for 44 h. After 44 h of IVM, denuded oocytes were co-cultured with spermatozoa during 18 h. After 18 h of in vitro fertilization, oocyte were using aceto-orcein method, to evaluated penetration rate, monospermy (number of monospermy oocytes/total oocytes), and the IVF efficiency (number of monospermy/total penetrated oocytes). In results, 25 and 50 μM ALA groups were significantly increased on penetration rate compared with 100 μM ALA group (p<0.05). Similarly, monospermy rate were significantly increased 25 and 50 μM ALA groups than control group (p<0.05). IVF efficiency was no significant difference between control and ALA treatment groups. Our findings suggested that treatment of ALA supplementation during in vitro maturation (IVM) and subsequent of in vitro fertilization in pigs, ALA can increase IVF efficiency by effectively blocking polyspermy and increasing monospermy some mechanism in porcine oocytes. However, the study of mechanism by which ALA blocks polyspermy are needed, and this study suggests that ALA has a positive effect on in vitro production of porcine oocytes by decreasing polyspermy. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Education) (2016R1D1A1B03931746).
        12.
        2017.12 구독 인증기관 무료, 개인회원 유료
        Alpha-linolenic acid (ALA) is one of n-3 polyunsaturated fatty acids and found mainly in the chloroplasts. Many studies have been reported that intracellular reactive oxygen species (ROS) in mammalian oocytes were reduced by supplementation of ALA in in vitro maturation (IVM) medium. Based on these reports, we expected that ALA acts as an antioxidant during IVM of porcine oocytes. Therefore, the objective of this study was to investigate the antioxidant effect of ALA supplementation during IVM in porcine oocytes. The cumulus-oocyte complexes (COCs) were incubated in IVM medium containing 200 μM H2O2 or H2O2 with 50 μM ALA for 44 h. Nuclear maturation stage of oocytes was evaluated using aceto-orcein method. For measurement of oxidative stress state, intracellular ROS and glutathione (GSH) levels were measured using carboxy-DCFDA and cell tracker red, respectively. In results, oocytes in metaphase-II (MII) stage development was significantly reduced in H2O2 group compared to non-treated control group (61.84±1.42% and 80.00%, respectively; p<0.05) and it was slightly recovered by treatment of ALA (69.76±1.67%; p<0.05). The intracellular GSH levels was decreased in H2O2 groups compared with control groups, but it was enhanced by ALA treatment (p<0.05). On the contrary, H2O2 treatment increased intracellular ROS level in oocytes and H2O2-induced ROS was decreased by treatment of ALA (p<0.05). Our findings suggested that ALA treatment under oxidative stress condition improve oocyte maturation via elevated GSH and reduced ROS levels in oocytes. Therefore, these results suggest that ALA have an antioxidative ability and it could be used as antioxidant in in vitro production system of porcine embryo.
        4,000원
        13.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        분노반응검사(Evans & Stangelang, 1971)는 분노를 유발하는 자극의 관점에서 분노수준을 평가하는 도구이다. 그러 나 이는 고령자를 대상으로 사용하기에는 문항수가 너무 많아 적은 수의 문항으로 구성된 분노반응검사가 필요하다. 본 연구의 목적은 신뢰성이 높고 타당한 단축형 분노반응검사를 제작하는 것이다. 연구 1에서는 60세 이상의 고령자들 에게 76문항으로 구성된 분노반응검사를 실시하였으며, 검사이론에 기초하여 76개의 문항들 중에서 10개의 문항을 추출하여 단축형 분노반응검사를 제작하였다. 연구 2에서는 60세 이상의 고령자들로 구성된 또 다른 표본을 대상으로 단축형 분노반응검사와 타당도 확인을 위한 검사들을 함께 실시하여 신뢰도와 타당도를 평가하였다. 노인용 단축형 분노반응검사의 Cronbach 는 .79로 양호한 수준의 신되도를 보였다. 노인용 단축형 분노반응검사는 특성분노를 반영하 는 검사이므로, 특성분노를 측정하는 검사점수와 상관이 높아야하고, 분노의 다른 측면을 반영하는 점수와는 낮은 상관을 보여야 타당하다. 노인용 단축형 분노반응검사 점수는 상태-특성 표현 척도의 특성분노 점수와 .60이상의 높은 상관을 보였으며, 분노표출 점수와 .39의 상관을 보였고, 적대감 점수와 .41의 상관을 보였다. 결론적으로, 본 연구에서 제작한 단축형 분노반응검사는 신뢰할 수 있고 타당한 검사인 것으로 나타났다.
        4,000원
        14.
        2017.03 구독 인증기관 무료, 개인회원 유료
        The oocyte undergoes various events during In vitro maturation (IVM) and subsequence development. One of the events is production of reactive oxygen species (ROS) that is a normal process of cell metabolism. But imbalances between ROS production and antioxidant systems induce oxidative stress that negatively affect to mammalian reproductive process. In vitro environments, In vitro matured oocytes have many problems, such as excessive production of ROS and imperfect cytoplasmic maturation. Therefore, In vitro matured oocytes still have lower maturation rates and developmental competence than in vivo matured oocytes. In order to improve the IVM and In vitro culture (IVC) system, antioxidants, vitamins were added to the IVM, IVC medium. Antioxidant supplementation was effective in controlling the production of ROS and it continues to be explored as a potential strategy to overcome mammalian reproductive disorders. Based on these studies, we expect that the use of antioxidants in porcine oocytes could improved maturation and development rates.
        4,000원
        15.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to investigate change of plasminogen activators (PAs) and their inhibitors (PAIs) mRNA and protein expression level by heat stress in porcine endometrial cells. The endometrial epithelial cells were isolated from endometrial epithelium in porcine uterus and cultured in different temperature conditions (38.5 and 41.5℃) for 24 h. Expression of urokinase-type PA (uPA), tissue-type PA (tPA), PA inhibitor-1 (PAI-1) and -2 (PAI-2) mRNA in epithelial cells were analyzed using reverse transcription-PCR and protein levels were measured by immunofluorescence. In result, mRNA expression of uPA, tPA, PAI-1 and PAI-2 were decreased in 41.5℃ than 38.5℃ culture condition, however, significant differences were no detected. uPA, tPA and PAI-2 protein were mainly expressed in nucleus, whereas PAI-1 was distributed in cytoplasm and nucleus. uPA and tPA protein levels were increased by heat stress treatment and significant difference was only detected in tPA level (p<0.05). In contrast, two types of PAIs protein level were decreased in 41.5℃ cultured group compared with 38.5℃ group. In present study, tPA protein expression was upregulated by heat stress in porcine endometrial cells. This result suggest that change of tPA by heat stress may be related to blood flow into uterus and intrauterine microenvironments, and could directly and indirectly influence to reproductive performance in pigs.
        4,000원
        16.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 농인들이 감정을 경험하고 표현할 때 그 특성이 청인과 어떻게 다른지 알아보았다. 이를 위해 농인과 청인 청소년들을 대상으로 세 가지 감정을 유발 시키면서 얼굴 표정을 녹화하였다. 감정의 경험 내용은 자기보고식 척도를 사용하여 측정되었고, 감정의 표현은 녹화된 얼굴 표정을 평정하였다. 두 집단 간에 경험 감정 속성이 동일한지 그리고 본인이 보고한 감정과 타인이 평가한 감정이 일치하는지를 비교하였다. 경험 감정의 유형 및 강도 점수는 청인과 농인 집단 간에 통계적으로 유의한 차이가 없었다. 그러나 표현 감정 평정 결과는 기쁨에서 두 집단 간에 유의한 차이를 보였다. 청인들의 기쁜 표정은 본인이 느낀 강도보다 타인에게 더 강하게 평가되는 반면, 농인들은 본인이 느낀 기쁨의 강도보다 훨씬 낮게 평가되었다. 이는 농인들의 감정 상태를 청인들은 알아차리지 못할 수 있다는 의미이다. 이러한 결과는 농인 청소년들의 감정 표출 방식이 같은 또래의 청인들과 달라 서로간의 감정적 교류나 대인관계에 어려움을 겪을 수 있음을 시사한다.
        4,000원
        17.
        2016.09 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to evaluate effect of α-linolenic acid (ALA) on viability, acrosome reaction and mitochondrial intact in frozen-thawed boar sperm. The boar semen was collected by gloved-hand method and cryopreserved in 20% egg yolk freezing extender containing ALA (0, 3, 5, and 10 ng/mL) with 0.05% ethanol. The frozen-boar spermatozoa were thawed at 37.5°C for 45 sec in water-bath. The spermatozoa samples were evaluated the plasma membrane integrity, acrosome reaction, and mitochondrial integrity using flow cytometry. In results, population of live sperm with intact plasma membrane was significantly higher in control and 3 ng/mL ALA treatment group than ethanol group (p<0.05). In contract, dying sperms were higher in ethanol group than 3 ng/mL ALA treatment (p<0.05). Acrosomal membrane damage in all sperm population was reduced in 3 ng/mL ALA groups compared with ethanol treatment (p<0.05). However, acrosome damage in live sperm population was no significant difference among the all treatment groups. Mitochondrial integrity was not influenced by ALA treatments in both of live and all sperm population. In conclusion, this results show that supplement of ALA during the cryopreservation process could reduce the membrane damages including plasma and acrosomal membrane, whereas ALA did not influence to mitochondria in boar spermatozoa. Therefore, these results suggest that ALA can protect against the membrane damage derived cryo-stress, and cryopreservation efficiency of boar semen would be improved by use of ALA.
        4,000원
        18.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구의 목적은 해류 모식도 그리기를 통해 드러난 중등 지구과학 교사들의 동해 해류에 대한 지식의 변화를 분석하는 것이다. 이를 위해 32명의 중등 지구과학 교사들이 총 6시간의 해류도 관련 학습과 실습 과정을 거쳤으며, 사전과 사후 그리고 지연된 사후 동해 해류 모식도 그리기를 수행하였다. 또한, 작성된 해류 모식도를 수치화 과정을 거쳐 변환하여 이 해류 모식도에서 드러난 참여 교사들의 동해 해류에 대한 지식의 변화를 분석하였다. 동해 해류에 대한 참여 교사들의 사전 지식을 분석한 결과, 해류도에 대한 기초적인 지식은 가지고 있는 것으로 나타났으나, 몇몇 개념에 대해서는 잘못된 지식을 가진 것으로 분석되었다. 3차에 걸쳐 작성된 참여 교사들의 동해 해류 모식도를 분석한 결과, 연수 후 동해 해류 양상에 대한 지식이 증가하는 것으로 나타났으며, 교사에 따른 차이는 감소하는 것으로 나타났다. 이러한 경향은 연수 직후보다는 지연된 사후 단계에서 더욱 뚜렷하게 나타났다. 해류도 실습활동에 대한 사후 설문을 분석한 결과, 참여 교사들은 해류도와 해류 교육의 필요성, 과학적 지식에 근거한 교과서 해류도의 개선을 강하게 인식하고 있었다. 또한, 실습활동에 대해 매우 높은 만족도를 나타내었으며, 내용 지식의 중요성 인식 및 교수 전략과의 연계, 중등 교육과정 개선의 필요, 과학 지식의 본성에 대한 인식 등 다양한 측면에서 실습활동의 의미를 부여하였다. 이러한 결과는 교사의 교과내용학 지식이 효과적인 과학 교수에 중대한 역할을 함을 시사한다.
        5,800원
        19.
        2015.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        75세 남자환자가 3개월 전부터 지속된 복부 불편감과 식욕 저하로 병원을 방문하였고, 복부전산화단층촬영을 시행한 결과 췌장 발육 부전증과 췌장 두부의 종괴, 복막의 비후가 관찰되었다. 자기공명담췌관촬영술과 내시경역행담췌관 조영술에서 주 췌관은 정상이었으나 췌부와 미부의 췌관 및 산토리니관은 관찰되지 않았다. 양전자방출단층촬영에서 복막과 폐의 암전이 소견이 나타났으며, 복수천자에서 얻은 세포검사에서 선암종이 확인되어 타 장기의 전이가 진행된 췌장암을 진단하였다. 이에 저자는 췌장암이 동반된 배측 췌장 발육 부전증 1예를 보고하는 바이다.
        4,000원
        20.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 음성 인식기에서 일반적으로 사용되는 음향적 특징인 MFCC, LPC, 에너지, 피치 관련 파라미터들을 이용하여 자연스러운 음성의 정서를 범주 및 차원으로 얼마나 잘 인식할 수 있는지 살펴보았다. 자연스러운 정서 반응 데이터를 얻기 위해 선행 연구에서 이미 타당도와 효과성이 밝혀진 정서 유발 자극을 사용하였고, 110명의 대학생들에게 7가지 정서 유발 자극을 제시한 후 유발된 음성 반응을 녹음하여 분석에 사용하였다. 각 음성 데이터에서 추출한 파라미터들을 독립변인으로 하여 선형 판별 분석(LDA)으로 7가지 정서 범주를 분류하였고, 범주 분류의 한계를 극복하기 위해 단계별 다중회귀(stepwise multiple regression) 모형을 도출하여 4가지 정서 차원(valence, arousal, intensity, potency)을 가장 잘 예측하는 음성 특징 파라미터를 산출하였다. 7가지 정서 범주 판별율은 평균 62.7%이었고, 4 차원 예측 회귀모형들도 p<.001수준에서 통계적으로 유의하였다. 결론적으로, 본 연구 결과는 자연스러운 감정의 음성 반응을 분류하는데 유용한 파라미터들을 선정하여 정서의 범주와 차원적 접근으로 정서 분류 가능성을 보였으며 논의에 본 연구의 개선방향에 대해 기술하였다.
        4,000원
        1 2