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        검색결과 21

        7.
        2015.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 저장볼트(storage vault)의 실험을 위하여 1/4 축소모델 내 튜브의 적정 발열량을 선정하고자 상사해석을 수 행하였다. 저장볼트에 대한 열 및 유동 해석을 우선적으로 수행하였고, 크기를 1/4로 축소한 저장볼트에 대하여 동일한 전 산해석을 수행하였다. 전산해석 결과를 바탕으로, 제안된 무차원수를 비교하여 원형모델과 온도분포와 유동분포가 유사하 게 되는 발열량을 선정하였다. 1/4 축소 저장볼트 내 튜브의 열유속이 1.3배일 때, 원형 저장볼트와 1/4 축소 저장볼트의 온 도장 및 유동장이 상사되었다. 이 때, 1/4 축소 저장볼트 내 발열량은 약 190 W이다.
        4,000원
        13.
        2013.03 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        14.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 2001년부터 2010년까지의 사료용 옥수수 및 밀의 수입량을 조사하고, 이를 바탕으로 가상수 개념을 활용하여 사료 곡물 수입에 따른 농업용수 및 농경지 대체 효과를분석하였다. 그 결과 사료용 옥수수와 밀을 통하여 수입되는가상수는 평균적으로 6,757백만 m3/yr 및 1,405백만 m3/yr씩 수입되는 것으로 분석되었다. 따라서 두 사료곡물을 통하여 약8,162백만 m3/yr만큼의 농업용수를 대체 효과가 있음을 의미하는데, 이는 농업용수 수요량의 51.5%에 해당되는 양이다. 한편 전적으로 해외수입에 의존하는 사료용 옥수수와 밀을 국내생산으로 대체하기 위해 필요한 잠재적 농경지 면적은 평균적으로 1,945천 ha와 285천 ha인 것으로 추정되었다. 이와 같이대외 의존도가 높은 상황에서 곡물 수급이 원활하지 않은 경우, 농작물 생산에 필요한 기술 등의 여력이 충분하더라도 수자원 및 농경지 부족으로 필요한 양의 농작물 생산에 어려움을 겪을 수도 있다. 특히 한정된 수자원에 대하여 농업, 생활및 공업용수 등의 이용에 대한 갈등을 야기할 수 있다. 위와같이 사료용 옥수수와 밀의 수입을 통한 농업용수의 양과 경작지 대체 면적이 많은 상황에서 정부는 2010년 기준으로37.5%인 자급률을 2015년과 2020년에 각각 41.2%와 44.4%로 목표치 설정하였다. 이와 같이 설정한 식량자급률 목표치달성을 위해서는 사료용 곡물의 국내생산 증대가 불가피함을고려할 때, 향후 사료용 곡물 국내생산을 위한 농업용수와 경작지 확보가 필수적이며, 이를 위한 다양한 정책 수립시 수자원 및 농경지 소요량 추정 등의 기초 자료로 본 연구 결과가활용될 수 있을 것으로 판단된다. 본 연구는 축산사료의 주요원료인 옥수수와 밀에 초점을 두고 연구가 이루어졌는데, 향후 기타 사료작물 및 조사료에 관련된 연구가 추가로 이루어진다면, 보다 종합적으로 국내 사료용 곡물의 국내자급 향상을 위한 정책대응 방안 탐색이 가능할 것으로 판단된다.
        4,000원
        15.
        1988.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        These studies were conducted to investigate the effect of repreated superovulation on embryo production, the effect of the frozen-thawed embryos transferred on the developmental stage and grade, and donor-recipient synchrony on pregnancy rate in Korean native cattle. The results obtained in these studies were as follows: 1. Repeated superovulations in Korean Native Catile were not affected on the number of corpus luteum (CL), embryos recovered and embryos cleaved (range: 4.8 4.21 to 9.5 6.50, 1.8 2.53 to 8.2 8.04 and 1.6 2.32 to 4.0 4.59, respectively). 2. Blastocyst embryos (38.5%) showed higher pregnancy rate than morula (31.6%). 3. The pregnancyrates of cattle transferred with good and fair embryos were 33.3% and 40.4%, respectively. 4. The pregnancy rate when the donors exhibited estrus 12 hours earlier than the recipients (62.5%) was higher than when the donors and recipients exhibited estrus at the same time (33.3%) or when the donors exhibited estrus 12 hours later than the recipients (20.0%).
        4,000원
        16.
        1983.12 구독 인증기관 무료, 개인회원 유료
        These studies were carried out to investigate the induction of superovulation, the synchroniration and the effect of the number of embryos transferred, the developmentai stage of embryos and the donor-recipient synchrony on pregnancy rate in cattle. The results obtained in these studies were as follows: 1. The number of oorpus leuteum(CL) and the embryos reoovered were higher in FSH treated animals than in PMSG treated (9.4 vs 8.1 and 6.1 vs 4.5) and showed the same trend in recovery rate (64.9% vs 55.6%). 2. Two shots of cioprostenol at 11 days showed significantly high no. of animals in estrus in order of crossbred, Holstein and Korean native cattle. No significant differencies were noted in the seoond shots groups. And the interval to estrus and response were shorter and better in second shot group than that in first shot group. 3. The pregnancy rate when additional one embryo was transferred after Al at estrus (52.8%) was higher than the group transferred one (32.8%) or two (36.9%) embryos. 4. The pregnancy rate of embryo in morula stage was better than that in blasto cyst stage (39.3% vs 32.5%). 5. The pregnancy rate in the recipients exhibited estrus later than the donor (66.7%) was the higher than those exhibited estrus (40.3%) or exhibited estrus before the donor (37.5%).
        4,000원
        17.
        2017.03 KCI 등재 서비스 종료(열람 제한)
        Existing agricultural reservoirs are considered as alternative source for the water welfare of rural area. In this study, domestic water supply potential of 476 reservoirs, which has storage capacity more than one million cubic meter, out of 3,377 agricultural reservoirs managed by Korean Rural Community Corporation (KRC) were investigated. Among them water quality of 136 reservoirs met the criteria of domestic water source which show less than COD 3 ppm. Available amount for domestic water of reservoirs, which meet the water quality, for ten year return period of drought was analyzed with reservoir water balance model. The results showed that 116 reservoirs has potential for supplementary domestic water supply while satisfying irrigation water supply. Finally, economic analysis using Net Present Value (NPV), Benefit–Cost (B/C) ratio, Internal Rate of Return (IRR), and Profitability Index (PI) methods was also conducted. The analysis showed that 19 reservoirs satisfied economic feasibility when water is provided from reservoir outlet but only 9 reservoirs meet the economic feasibility if water delivered from a reservoir to treatment plant by newly built conveyance canal. In order to supply the domestic water through the agricultural reservoirs managed by KRC, it is necessary to flexibly interpret and operate the ‘Rearrangement of Agricultural and Fishing village Act’. Also, it is reasonable to participate in the water service business when there is a supply request from other Ministries. In addition, the KRC requires further effort to change the crop system for saving water and improve efficiency of irrigation systems.
        18.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        Meanwhile, reference evapotranspiration(ET0) is important information for agricultural management including irrigation planning and drought assessment, the database of reference evapotranspiration for future periods was rarely constructed especially at districts unit over the country. The Coupled Model Intercomparison Project Phase 5 (CMIP5) provides several meteorological data such as precipitation, average temperature, humidity, wind speed, and radiation for long-term future period at daily time-scale. This study aimed to build a database for reference evapotranspiration using the climate forecasts at high resolution (the outputs of HadGEM3-RA provided by Korea Meteorological Administration (KMA)). To estimate reference evapotranspiration, we implemented four different models such as FAO Modified Penman, FAO Penman-Monteith, FAO Blaney-Criddle, and Thornthwaite. The suggested database system has an open architecture so that user could add other models into the database. The database contains 5,050 regions’ data for each four models and four Representative Concentration Pathways (RCP) climate change scenarios. The developed database system provides selecting features by which the database users could extract specific region and period data.
        19.
        2013.05 KCI 등재 서비스 종료(열람 제한)
        Recently, the occurrences of droughts have been increased because of global warming and climate change. Water resources that mostly rely on groundwater are particularly vulnerable to the impact of precipitation variation, one of the major elements of climate change, are very sensitive to changes in the seasonal distribution as well as the average annual change in the viewpoint of agricultural activity. In this study, the status of drought for the present and future on Jeju Island which entirely rely on groundwater using SPI and PDSI were analyzed considering regional distribution of crops in terms of land use and fluctuation of water demand. The results showed that the precipitation distribution in Jeju Island is changed in intensity as well as seasonal variation of extreme events and the amount increase of precipitation during the dry season in the spring and fall indicated that agricultural water demand and supply policies would be considered by regional characteristics, especially the western region with largest market garden crops. Regarding the simulated future drought, the drought would be mitigated in the SPI method because of considering total rainfall only excluding intensity variation, while more intensified in the PDSI because it considers the evapotranspiration as well as rainfall as time passed. Moreover, the drought in the northern and western regions is getting worse than in the southern region so that the establishment of regional customized policies for water supply in Jeju Island is needed.
        20.
        2010.06 KCI 등재 서비스 종료(열람 제한)
        Land cover and land use change data are important in many studies including climate change and hydrological studies. Although the various theories and models have been developed, it is difficult to identify the driving factors of the land use change because land use change is related to policy options and natural and socio-economic conditions. This study is to attempt to simulate the land cover change using the CLUE model based on a statistical analysis of land-use change. CLUE model has dynamic modeling tools from the competition among land use change in between driving force and land use, so that this model depends on statistical relations between land use change and driving factors. In this study, Yongin, Icheon and Anseong were selected for the study areas, and binary logistic regression and factor analysis were performed verifying with ROC curve. Land cover probability map was also prepared to compare with the land cover data and higher probability areas are well matched with the present land cover demonstrating CLUE model applicability.
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