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        검색결과 36

        1.
        2022.05 구독 인증기관·개인회원 무료
        The International Atomic Energy Agency recommends the deep geological disposal system as one of the disposal methods for high-level radioactive waste (HLW), such as spent nuclear fuel. The deep geological disposal system disposes of HLW in a deep and stable geological formation to isolate the HLW from the human biosphere and restrict the inflow of radionuclides into the ecosystem. It mainly consists of an engineered barrier and a natural barrier. Safety evaluation using a numerical model has been performed primarily to evaluate the buffer’s long-term stability. However, although the gas generation rate input for long-term stability evaluation is the critical factor that has the most significant influence on the long-term hydraulic-mechanical behavior of the buffer, in-depth research and experimental data are lacking. In this study, the gas generation rate on the interface between the disposal canister and the buffer material, a component of the engineered barrier, was mainly studied. Gas can be generated between the disposal canister and the buffer material due to various causes such as anaerobic corrosion of the disposal canister metal, organic matter decomposition, radiation decomposition, and steam generation due to high temperature. The generation of gas in such a disposal environment increases the pore gas pressure in the buffer and causes internal cracks. The occurred cracks increase the intrinsic permeability of the buffer, which leads to a decrease in the primary performance of the buffer. For this reason, it is essential to apply the appropriate gas generation rate according to the disposal condition and buffer material for accurate long-term stability analysis. Therefore, the theoretical models regarding the estimation of gas generation were summarized through a literature study. The amount of gas generated was estimated according to the disposal environment and material of the disposal canister. It is expected that estimated values might be used to estimate the long-term stability analysis of buffer performance according to the disposal condition.
        4.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is to compare the effect of estrus synchronization and embryo transfer between Korean and Mongolian cattle. Embryos were collected from 9 donors housed in Asan city in South Chungcheong Province, South Korea. Embryos were collected 9 donors from Khushaat sum, Selenge province and Bayanchandmani sum, Tov province in Mongolia. Follicle Stimulating Hormone (FSH), Controlled Internal Drug Release (CIDR) and Prostaglandin (PG) were used for superovulation. Subsequently, Artificial Insemination (AI) was done for donor cow and embryo was collected after 7 and 8 days. Collected embryos were compared between Mongolian and Korean cattle. Finally, good quality and fresh embryos were transferred to 50 and 22 recipients of cows in Korea and Mongolia respectively. The findings show that Korean native cattle each donor cow produced on an average 16.9 embryos and, 10.9 embryos were found transferable. But in case of Mongolia the average production of embryos per donor cow was 8.6 embryos and, 6.2 embryos were found transferable. Embryo collection after 7 and 8 days was not difference in embryo production in Korea. But, in Mongolia embryo production after 8 days was found more efficient than the 7 days. Korean native recipient's cows (74.6%) and Mongolian recipient's cows (71.0%) respectively were found transferable ovarian stage. The result suggested that efficiency of embryo production from the superovulation method treated of Korean cow were higher than the Mongolian cow. The pregnancy rate of Korea native cattle was 72%, which was about 10% higher than that of Mongolia cattle.
        4,000원
        5.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The performance of the new aerobic digestion system combined with inorganic sludge separation unit and sludge solubilization unit, CaviTec II, is evaluated. Anaerobic digester effluent sludge is used for feed sludge of CaviTec II system. By addition of CaviTec II, the amount of cake generated is reduced by 27%, and the soluble nitrogen is reduced by 92%.
        4,000원
        7.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Body condition score (BCS) is a useful management tool for distinguishing differences in nutritional needs of cows in the herd. Although it is not always possible to quantify the nutrient content of the feed supplied to the donor cow, the nutritional status can be determined by the BCS. The objective of this study was to evaluate in vivo embryo production, return to estrous of donor and pregnancy rate of recipients following BCS in Hanwoo superovulation. Sixty nine Hanwoo donor cows were flushed on day 7 of estrus cycle with same FSH and artificial insemination by the same technicians. Embryos were recovered on 7 days after the third insemination by flushing the uterus with Embryo Collection Medium. The results obtained were as follows: No differences were observed in the efficiency of superovulation rates regardless of BCS (≦2.0, 2.5 to 3.0, and ≧3.5). The mean number of total embryos was each 5.20±0.86, 11.56±1.04, and 6.23±1.07. The mean number of transferable embryo from ≦2.0, 2.5 to 3.0, and ≧3.5 of BCS was 2.60±0.87, 7.94±0.89, and 4.75±1.32, respectively (p<0.05). Return to estrous regardless of donor BCS was no difference. The pregnancy rates of recipient were BCS ≦2.0 11.76%, 2.5 to 3.0 40.79%, and ≧3.5 11.11%, following transfer of fresh embryos produced in vivo, respectively. These results indicate that if the Hanwoo with BCS 2.5 to 3.3 are used for donor and recipient, the embryo production and the conception rate will be greater.
        4,000원
        9.
        2012.09 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate the comparison of transferable embryos and pregnancy rate between Hanwoo and Chickso. The results obtained were as follows: No differences were observed in the efficiency of superovulation rates on Hanwoo 78%, and Chickso 85%, respectively. The mean number of total embryos are each 14.76± 2.16 and 6.23±1.07. So the mean number of transferable embryos are each 10.94±1.91 and 4.58±1.05. In addition, the mean number of total Hanwoo embryo from <10 and 10≤ of corpora luteum was 0.50±0.50, 11.56±1.92, respectively. In case of Chickso, The mean number of transferable embryo from <10 and 10≤ of CL was 2.75±1.39, 6.00±1.00, respectively. The pregnancy rates were Hanwoo 40%, and Chickso 37% following transfer of fresh embryos produced in vivo. Also, the pregnancy rates of Chickso 60% were significantly greater (p<0.05) than the Hanwoo 42.48% following transfer of following transfer of frozen embryos, respectively. In conclusion, these results suggest that Chickso may be effectively used for transferable embryos production in Hanwoo. Although the transferable embryos number was not enough, it seems the Chickso greatly affect pregnancy rate. The results indicated that the possibility of transferable embryos from Chickso for embryo transfer could be confirmed in this study. Based on the present findings, it was suggested that it is very important to evaluate in vivo embryo production and pregnancy rate of embryo transfer following superovulation for effective Hanwoo and Chickso production.
        4,000원
        11.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 한약재 (결명자, 계피, 산초, 감초) 추출물의 반추위내 발효와 미생물 활성에 대한 효과를 구명하기 위하여 수행되었다. In vitro 건물소화율은 계피와 산초 추출물 첨가구에서는 0시간대, 감초 추출물 첨가구에서는 3시간대에 대조구에 비해 현저히 (P<0.05) 낮았다. 한약재 추출물 첨가에 따른 발효 시간대별 휘발성 지방산 조성의 변화는 3시간대에서만 처리간 유의성이 인정되었는데, acetate 비율은 대조구가 천연 추출물 첨가구보다 유의적으로 높았으나, butyrate, isobutyrate, isovalerate 및 valerate은 대조구에서 가장 낮았다 (P<0.05). 미생물 성장율은 발효 3시간대에서 결명자 첨가구를 제외한 한약재 첨가구에서 대조구에 비해 유의적(P<0.05)으로높았으나다른발효시간대에서는차이가없었다 이상의 결과로부터 한약재로 사용되고 있는 계피, 산초 및 감초 추출물을 in vitro 반추위 배양액에 첨가하였을 때, 발효초기에 반추위 미생물의 활성을 억제하는 경향은 있었으나 미생물 성장에 대한 억제 효과는 없는 것으로 나타났다.
        4,000원
        13.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        팽이버섯 생산비용을 절감하기 위하여 한번 사용한 배지의 적정 혼합비율을 구명하고자 시험한 결과는 다음과 같다. 팽이버섯 재배 배지재료로 미송톱밥, 1회 팽이버섯 재배에 사용한 톱밥, 콘코브 그리고 영양원으로 미강과 밀기울을 이용하여 14가지로 배지를 조성하여 균사배양기간, 자실체 수량과 품질을 조사하였다. 두 가지 영양원에 따라 배양기간은 큰 차이가 없었지만 유효경수, 자실체 수량과 품질은 밀기울보다 미강이 좋았다. 폐배지를 20% 혼합한 처리 즉 미송톱밥 60%+폐배지 20%+미강 20% 배지가 관행처리 미송톱밥 80%+미강 20% 배지와 품질은 비슷하며 수량은 142.2g 으로 관행의 130g 대비 10% 증수하였다. 그러나 폐배지 혼입량이 증가함에 따라 자실체의 품질과 수량이 현저하게 감소하였다. 따라서 폐배지의 적정 혼합량은 20%이며 수량도 10% 증가하였다.
        4,000원
        19.
        2007.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        큰느타리버섯의 재배면적 및 생산량 증가에 따라 많은 양의 폐배지가 발생되고 있다는 사실을 염두에 두고 그 활용도를 높이고자 농가로부터 수거된 폐배지에 대해 성분분석 및 버섯균사에 대한 생육저해 여부를 확인한 뒤 버섯재배에 있어 폐배지의 적정첨가 비율을 결정하고 그에 따른 버섯의 배양특성 및 생육특성을 관찰하였다. 폐배지 성분분석 결과 pH는 새배지에 비해 낮아지는 경향을 보였고 총 질소 함량은 폐배지 첨가비율 많아질수록 높아지는 경향을 나타내었다. 버섯의 배양 및 생육과정 중 배지로 분비된 대사산물에 의해서 일어 날수 있는 버섯 균사생육저해 현상을 조사하기 위해 폐배지 열수추출물을 이용하여 만들어진 고체배지에 버섯 균사를 접종한 결과 폐배지에 의한 버섯균사 저해현상은 확인되지 않았다. 폐배지 첨가에 따른 배양특성을 조사한 결과 첨가량이 증가할수록 균사생장률은 약간씩 낮아지는 경향을 나타내었으나 50% 이내로 폐배지가 첨가된 조건에서는 일반적인 배양기간 (35일) 내에 배양이 완료된다는 사실을 확인 할 수 있었다. 버섯의 발이특성을 조사한 결과에 있어서도 50% 이내로 폐배지가 첨가된 경우 평균 10일 이내에 발이가 완료되었으나 폐배지 100%로 제조된 배지에서는 정상적으로 발이가 되지 못하였다. 생육특성의 경우 평균 18일 이내에 수확이 완료되었으나 폐배지 첨가량이 30% 이상 일 경우 자실체수량이 감소하였다. 이상의 결과를 요약하면 큰느타리버섯 재배농가에서 정상적으로 재배되고 발생되는 폐배지의 경우 버섯 잔재물이나 배지 덩어리 및 오염배지와 같은 이물질을 제거한 뒤 10-30% 수준으로 새배지에 첨가하여 재활용 할 경우 정상적인 버섯의 배양 및 생육이 가능하였으며, 이러한 사실은 버섯 재배농가의 재료비 절감에 도움을 줄 수 있을 것을 기대된다.
        4,000원
        20.
        2004.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Synthesis gas is a high valued compound as a basic chemicals at various chemical processes. Synthesis gas is mainly produced commercially by a steam reforming process. However, the process is highly endothermic so that the process is very energy-consuming process. Thus, this study was carried out to produce synthesis gas by the partial oxidation of methane to decrease the energy cost. The effects of reaction temperature and flow rate of reactants on the methane conversion, product selectivity, product ratio, and carbon deposition were investigated with 13wt% Ni/MgO catalyst in a fluidized bed reactor. With the fluidized bed reactor, CH4 conversion was 91%, and Hz and CO selectivities were both 98% at 850℃ and total flow rate of 100 mL/min. These values were higher than those of fixed bed reactor. From this result, we found that with the use of the fluidized bed reactor it was possible to avoid the disadvantage of fixed bed reactor (explosion) and increase the productivity of synthesis gas.
        4,000원
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