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        검색결과 7

        1.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The piezoelectric energy road analysis technology using a three-dimensional finite element method was developed to investigate pavement behaviors when piezoelectric energy harvesters and a new polyurethane surface layer were installed in field conditions. The main purpose of this study is to predict the long-term performance of the piezoelectric energy road through the proposed analytical steps. METHODS: To predict the stresses and strains of the piezoelectric energy road, the developed energy harvesters were embedded into the polyurethane surface layer (50 mm from the top surface). The typical type of triaxial dump truck loading was applied to the top of each energy harvester. In this paper, a general purpose finite element analysis program called ABAQUS was used and it was assumed that a harvester is installed in the cross section of a typical asphalt pavement structure. RESULTS : The maximum tensile stress of the polyurethane surface layer in the initial fatigue model occurred up to 0.035 MPa in the transverse direction when the truck tire load was loaded on the top of each harvester. The maximum tensile stresses were 0.025 MPa in the intermediate fatigue model and 0.013 MPa in the final fatigue model, which were 72% and 37% lower than that of the initial stage model, respectively. CONCLUSIONS : The main critical damage locations can be estimated between the base layer and the surface layer. If the crack propagates, bottom-up cracking from the base layer is the main cracking pattern where the tensile stress is higher than in other locations. It is also considered that the possibility of cracking in the top-down direction at the edge of energy harvester is more likely to occur because the material strength of the energy harvester is much higher and plays a role in the supporting points. In terms of long-term performance, all tensile stresses in the energy harvester and polyurethane layer are less than 1% of the maximum tensile strength and the possibility of fatigue damage was very low. Since the harvester is embedded in the surface layer of the polyurethane, which has higher tensile strength and toughness, it can assure a good, long-term performance.
        4,000원
        2.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to estimate optimal harvesting production, fishing efforts, and stock levels of yellow croaker caught by the offshore Stow Net and the offshore Gill Net fisheries using the current value Hamiltonian method and the surplus production model. As analyzing processes, firstly, this study uses the Gavaris general linear model to estimate standardized fishing efforts of yellow croaker caught by the above multiple fisheries. Secondly, this study applies the Clarke·Yoshimoto·Pooley(CY&P) model among the various exponential growth models to estimate intrinsic growth rate(r), environmental carrying capacity(K), and catchability coefficient(q) of yellow croaker which inhabits in offshore area of Korea. Thirdly, the study determines optimal harvesting production, fishing efforts, and stock levels of yellow croaker using the current value Hamiltonian method which is including average landing price of yellow croaker, average unit cost of fishing efforts, and social discount rate based on standard of the Korean Development Institute. Finally, this study tries sensitivity analysis to understand changes in optimal harvesting production, fishing efforts, and stock levels of yellow croaker caused by changes in economic and biological parameters. As results drawn by the current value Hamiltonian model, the optimal harvesting production, fishing efforts, and stock levels of yellow croaker caught by the multiple fisheries were estimated as 19,173 ton, 101,644 horse power, and 146,144 ton respectively. In addition, as results of sensitivity analysis, firstly, if the social discount rate and the average landing price of yellow croaker continuously increase, the optimal harvesting production of yellow croaker increases at decreasing rate and then finally slightly decreases due to decreases in stock levels of yellow croaker. Secondly, if the average unit cost of fishing efforts continuously increases, the optimal fishing efforts of the multiple fisheries decreases, but the optimal stock level of yellow croaker increases. The optimal harvest starts climbing and then continuously decreases due to increases in the average unit cost. Thirdly, when the intrinsic growth rate of yellow croaker increases, the optimal harvest, fishing efforts, and stock level all continuously increase. In conclusion, this study suggests that the optimal harvesting production and fishing efforts were much less than actual harvesting production(35,279 ton) and estimated standardized fishing efforts(175,512 horse power) in 2013. This result implies that yellow croaker has been overfished due to excessive fishing efforts. Efficient management and conservative policy on stock of yellow croaker need to be urgently implemented.
        4,900원
        3.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This research is a basic study for application method in korea of energy harvesting technology, and it is a research to find out the direction of architectural planning through analyzing cases of interseasonal heat transfer system applied buildings. METHODS : In this paper authors investigate application necessity of energy harvesting technology, we analyzed energy use status of building section through analyzing domestic energy consumption status and analyzed domestic renewable energy generation potential. Also we study the features of energy harvesting technology, interseasonal heat transfer system, and case study on interseasonal heat transfer system applied buildings. RESULTS : On the basis of case study on interseasonal heat transfer system applied buildings, we analyzed feasibility study and classified into four sections(economic, environment, design, applicability), and suggested directions of architectural planning. CONCLUSIONS: Economic renewable energy for public and commercial buildings(hospitals, offices, schools, factories) can be provided effectively using Interseasonal Heat Transfer.
        4,300원
        4.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bone marrow (BM) cell harvesting is a crucial element in the isolation of mesenchymal stem cells (MSCs). A simple method for harvesting cat BM cells is described. The results show that a large number of BM cells can rapidly be harvested from the cat by this simple procedure. MSCs prepared by density-gradient method were spindle-shaped morphology with bipolar or polygonal cell bodies and strongly positive for CD9 and CD44 and negative for CD18 and CD45-like. They were capable of differentiation to adipocytic and osteocytic phenotypes when exposed to appropriate induction media. The advantages of this method are its rapidity, simplicity, low invasiveness, and low donor attrition and good outcome.
        4,000원
        5.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        This experiment was conducted to obtain basic a information on feed value and fermentative quality of whole crop barley with different harvesting time and making method. As a result, in case of feed value, crude protein, NDF and ADF content were decreased with late harvest, but TDN was increased. In the silage, the results were similar and these patterns showed the same before and after the silage making. Thus, there was no significantly difference in bale and chopper. In case of fermentative quality, pH of the silages showed increasing with late harvesting time but the contents of organic acid did lower, and those tendencies were the same in both bale and chopper condition. But the lactic acid content were approximately 23 percent higher in chopped condition. In conclusion, ensiling at yellow ripe stage is better than other stages, chopped ensiling could improve fermentation quality.
        6.
        2010.12 KCI 등재 서비스 종료(열람 제한)
        고 고형분함량 감자 생산을 위한 수확시기를 예측하는 데 있어 에너지 소모량의 추정에 대한 연구결과는 다음과 같다. 1. 각 지역별로 포장의 파종시기부터 수확시기까지 최근 5년간(2005년~2009년) 평균기온, 강수량, 상대습도, 일조시간, 바람, 지중온도 등의 농업환경을 조사한 결과 파종기 저온피해와 괴경비대기 장마기간을 회피한다면 가공용 원료감자는 가공품 생산에 필요시마다 물량을 수급하기 때문에 만숙재배를 하지 않아 품종의존도가 낮아 수확시기의 환경에 대한 비중이 큰 것으로 판단되었다. 2. 파종시기부터 출현까지에는 지중온도에 영향을 많이 받아 지역별 편차가 심해 시뮬레이션에서는 출현시기를 기준으로 감자의 수확적기를 예측하는 것이 바람직하였다. 3 수확시기를 예측하기 위한 생장모형은 Tp=Tm~cdotWmTpWmTm를 사용하고, 생장량 Wm을 계상하는 기본 생장모형은 Wm=~intmtf(x)dt 를 사용하였다. 4. 기본 생장모형을 통해 Wm을 계상할 때는 광합성율(δA )과 식물체내 에너지 소모(δE ) 개념을 적용해야 보다 정밀한 수확시기를 예측할 수 있었으며, 식물체내 에너지 소모에 대한 정의는 기후변화에 대응하여 농업환경에 대처하는 식물체내 에너지 소모를 계상하는 것으로 최근 5년간(2005년~2009년) 수확시기에 따라 고형분함량을 측정한 결과 광합성율만 계상할 때 보다 에너지 소모개념을 적용한 것이 효과적이었다.
        7.
        2006.02 KCI 등재 서비스 종료(열람 제한)
        작약의 재배 기간을 단축시켜 생산비를 줄이기 위한 시험을 수행하여 다음과 같은 결과를 얻었다. 하우스재배에서는 노지에 비하여 맹아의 출현과 개화가 촉진되었으나 지상부 및 뿌리의 생육이 불량하였고 2년생의 10a당 수량은 533kg으로 무처리 보다 19% 감수되었다. 분주묘 크기가 100g~130g인 대묘를 식재한 경우 2년생 뿌리 수량이 관행 재배 2년생에 비하여 15% 증수되었다. 대묘(노두 무게 100~130g)를 이랑너비 60cm, 포기사이 25cm로 밀식하고 흑색비닐을 식재부터 수확까지 2년간 피복한 것이 생육과 뿌리 품질이 양호하였고, 10 a당 뿌리수량이 902kg으로 가장 많았다. 작약을 3~4년 만에 수확하던 것에 대치하여 2년 만에 수확할 수 있는 방법은 대묘를 식재하거나, 대묘를 밀식하여 식재부터 수확까지 흑색비닐을 피복하는 방법인데, 이 경우 농가관행 3년생에 비하여 수량의 차이는 있었으나 10 a당 년간소득은 15~28% 향상되어 재배기간을 1년 단축시키고 경지 이용율을 높이면서 생산비를 획기적으로 줄일 수 있었다.