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          동맥경화 분자영상

          김동억,정상욱 대한의사협회 2009 대한의사협회지 Vol.52 No.2

          Atherosclerosis is characterized by progressive accumulation of lipids and inflammatory cells within the artery wall. It is a diffuse systemic disease; however, some atherosclerotic plaques are more prone to rupture causing sudden thromboembolic vascular occlusions, while others are clinically silent. Therefore, to prevent such devastating vascular events as stroke or myocardial infarction, clinicians need to have smart tools to localize high-risk vulnerable plaques, which have been a huge challenge to date. Molecular imaging, which visualizes biologic processes at the cellular and molecular level, has a potential to assess plaque vulnerability and consequently identify high-risk patients prior to the development of the clinical events. In this review, we summarize important updates on the molecular imaging of atherosclerosis in the field of optical imaging, magnetic resonance imaging, positron emission tomography, and computerized tomography imaging.

        • KCI등재

          인공습지에서의 물질순환에 관한 연구

          김동억,박제철 한국환경과학회 2020 한국환경과학회지 Vol.29 No.3

          This study analyzed the changes in the concentrations of the pollutants of constructed treatment wetlands which come from the discharge water of a sewage treatment plant. According to the results of budgets in constructed wetlands, the net production of the organic carbon, nitrogen and phosphorus were 368 kgC/month, 306 kgN/month and –49 kgP/month, respectively. The high particle form of pollutants are mostly removed due to settlement and absorption when passing through wetlands, but because a low processing efficiency for pollutants was shown when sewage treatment plant wastewater flows in, there is a need for a water management system that can reduce the organic matter load through monitoring. The low removal efficiency of constructed wetlands were caused by both structural and operational problems. Therefore, to enable to play a role as a reduction facility of pollutants, an appropriate design and operation manuals for constructed wetlands is urgently needed.

        • KCI등재
        • KCI등재

          국내 6개 하천에서 어도를 이용하는 어류상

          김동억,박제철,황종서,김동섭,이완옥,황길순 한국하천호수학회 2020 생태와 환경 Vol.53 No.3

          The use of fishway has been investigated up to 2~9 years, continuously each month and over the long term that installed in 6 domestic rivers. The fish’s use of fishway has been investigated as direct collection by trap in exit section of the fishway. The population structure of fish using 6 fishway and the fish that live in the river showed difference. About 2 to 7 species of fish took possession of more than 80% of total use of fish in fishways. This seems to be not the results of attraction flow in fishway but specialized result of physiology characteristic followed by species of fish. In addition, the distribution of fish species using fishway was different with the fishways installed in river. This difference seems to be consequence of the place that of the river and fishway types. Generally, the fish species were less and had high ratio of home migratory fish in vertical slot type fishway, which shows relatively fast velocity of water flow. This analysis result of major fish species using fishway can be used in planning fishway and to choose major targeted species for the planning.

        • KCI등재

          여름철 수시차광에 의한 온실 환경변화가 오이의 광호흡, 엽온, Thermal breakdown 등 생육에 미치는 영향

          김동억,권진경,홍순중,이종원,우영회 (사) 한국생물환경조절학회 2020 시설원예‧식물공장 Vol.29 No.3

          본 연구에서는 여름철 고온기 시설재배시 수시차광이 내부 환경과 오이 생리적 반응에 미치는 영향을 검토하였다. 온실 차광이 오이의 고온 스트레스 완화 정도를 추정하기 위하여 잎 온도, 엽기온차, 최대 카르복실화속도, 최대 전자전달 속도, 열파괴, 광호흡과 같은 오이의 생리적 반응을 측정 분석하였다. 오이 시설하우스의 차광율은 90% 수시차광, 40% 수시차광, 무차광 3수준의 실험 조건으로 하였다. 90% 수시차광은 외부 일사량이 650 W·m-2일 때 차광되도록 하였다. 기온, 일사량, 엽온, 엽기온차, 광호흡은 90%의 수시차광에서 40% 수시차광과 무차광 처리 보다 낮은 값을 나타내었다. 최대 카르복실화속도, 광호흡율은 90% 수시차광 온실이 다른 처리구 보다 유의하게 낮은 것으로 나타났다. 고온저항성을 나타내는 thermal breakdown 값은 90%의 수시차광에서 다른 처리구 보다 유의하게 높은 것으로 나타났다. 따라서, 90% 수시차광이 여름철 오이 재배에 있어 고온스트레스를 덜 받는 생육환경을 조성하였다는 결과를 얻었다. This study was conducted to investigate cucumber plants response to greenhouse environments by solar shading in greenhouse in the summer. In order to estimate heat stress reduction of cucumber plants by solar shading in greenhouse, we measured and analyzed physiological conditions of cucumber plants, such as leaf temperature, leaf-air temperature, rubisco maximum carboxylation rate, maximum electron transport rate, thermal breakdown, light leaf respiration, etc. Shading levels were 90% mobile shading of full sunlight, 40% mobile shading of full sunlight and no shading(full sunlight). The 90% shading screen was operated when the external solar radiation is greater than 650 W·m-2. Air temperature, solar radiation, leaf temperature, leaf-air temperature and light leaf respiration in the 90% shading of full sunlight was lower than those of 40% shading and no shading. Rubisco maximum carboxylation rate, arrhenius function value and light leaf respiration of the 90% shading were significantly lower than those of 40% shading and no shading. The thermal breakdown, high temperature inhibition, of 90% shading was significantly higher than that of 40% shading and no shading. Therefore, these results suggest that 90% mobile shading made a less stressful growth environment for cucumber crops.

        • KCI등재

          뇌MRI를 대리결론변수로 하는 임상시험을 위한 병변의 뇌표준판 등록 및 정량분석 소프트웨어 개발: 예비보고

          김동억,권건한,고은아,정지원,강동희,탁윤오,박경종,정상욱,최흥국,지명구,노상미,김태윤 대한신경과학회 2009 대한신경과학회지 Vol.27 No.4

          Background: Clinical trials that utilize imaging findings as surrogate endpoints are considered to be cost-effective. However, unlike numeric data, magnetic resonance imaging (MRI) findings are not quantifiable. Thus, we have begun to develop a software package that is able to convert qualitative MRI findings into quantifiable data. Methods: Computer software (DUIH_Image) was created with which every patient’s MRI data can be registered on a standard brain template. Interuser and intrauser reliabilities for the registration were measured, and then a proof-of-principle experiment was conducted to determine whether the system could identify factors that were associated with a greater National Institutes of Health Stroke Scale (NIHSS) score at admission. We studied 40 consecutive patients [65.1±14.2 years old (mean±SD); 22 males and 18 females] with first-ever acute lacunar infarction of the corona radiata, who were divided into two groups according to their NIHSS score (i.e., low: 0–2; high: ≥3). The following parameters were compared between these two groups: (1) data retrieved from clinical profiles, including demographic and risk factor variables; and (2) accumulated diffusion MRI lesions mapped on a standard template. Results: Modest levels of interuser and intrauser reliability were observed (p<0.05, R2=0.63–0.84, Pearson correlations). Regarding the clinical profiles, no significant difference was found for the numeric data sets or infarct size between the two groups. However, on the accumulated lesion map image, the lesion area that overlapped the most was located more posterolaterally in the high NIHSS score group than in the low NIHSS score group. Conclusions: In this pilot study we have demonstrated the potential usefulness of the DUIH_Image software. We plan to update this software to enable its utilization in actual clinical trials. Background: Clinical trials that utilize imaging findings as surrogate endpoints are considered to be cost-effective. However, unlike numeric data, magnetic resonance imaging (MRI) findings are not quantifiable. Thus, we have begun to develop a software package that is able to convert qualitative MRI findings into quantifiable data. Methods: Computer software (DUIH_Image) was created with which every patient’s MRI data can be registered on a standard brain template. Interuser and intrauser reliabilities for the registration were measured, and then a proof-of-principle experiment was conducted to determine whether the system could identify factors that were associated with a greater National Institutes of Health Stroke Scale (NIHSS) score at admission. We studied 40 consecutive patients [65.1±14.2 years old (mean±SD); 22 males and 18 females] with first-ever acute lacunar infarction of the corona radiata, who were divided into two groups according to their NIHSS score (i.e., low: 0–2; high: ≥3). The following parameters were compared between these two groups: (1) data retrieved from clinical profiles, including demographic and risk factor variables; and (2) accumulated diffusion MRI lesions mapped on a standard template. Results: Modest levels of interuser and intrauser reliability were observed (p<0.05, R2=0.63–0.84, Pearson correlations). Regarding the clinical profiles, no significant difference was found for the numeric data sets or infarct size between the two groups. However, on the accumulated lesion map image, the lesion area that overlapped the most was located more posterolaterally in the high NIHSS score group than in the low NIHSS score group. Conclusions: In this pilot study we have demonstrated the potential usefulness of the DUIH_Image software. We plan to update this software to enable its utilization in actual clinical trials.

        • KCI등재

          Fault Analysis Method for Power Distribution Grid with PCS-based Distributed Energy Resources

          김동억,조남훈 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.2

          In this study, we propose a fault analysis method for a power distribution grid with PCSbased DERs. We first explain the characteristics of a PCS-based DER. According to the characteristics, the DER is considered as a current-controlled voltage source, which produces varying voltages within a certain limit so that currents equal to given references flowing from the DER to the grid (currents controlled). So, we introduce the symmetrical equivalent models in the form of varying voltage source for fault analysis and then, construct a convex optimization problem to solve the fault problem associated with the equivalent models and grid conditions. Thus, the proposed method enables to perform a proper fault analysis considering the characteristics of the DER, which are currents controlled, voltage limited, and unity power factor achievement. To verify the validity of the proposed method, we perform computer simulations with the proposed method and with MATLAB Simulink, and the results are compared.

        • KCI등재

          박과 종자용 진공노즐식 파종기 개발(II) -대립종자의 종자보충, 정렬 및 파종성능시험 -

          김동억,장유섭,김종구,김현환,이동현 한국농업기계학회 2003 바이오시스템공학 Vol.28 No.6

          This study was carried out to develop a vacuum nozzle seeder for large seeds and performance was tested on seed feeding, arranging. and sowing peformance. The results of this study were as follows: The operation of feeding device of the seeder was programmed to operate a period of setting time after sowing 6 rows. The setting time was decided based on a discharged seed by the angular speed of feeding roller. The arranging accuracy of 'tuktozwa', 'hukjong' and 'chambak' was 96.4%, 95.2% and 89.4% respectively. The working performance was 75.6sheet/hr which was 3.8 times higher than that of manual work. An average seeding rate of 1 grain was 97.8%.

        • KCI등재

          광원과 양액이 상추 생육에 미치는 영향

          김동억,김봉수,김현배,김관우,윤용철,최만권,김치호,김현태 경상대학교 농업생명과학연구원 2013 농업생명과학연구 Vol.47 No.3

          In this study, targeted lettuce primarily planting in plant factory, LED irradiation time and nutrient composition was conducted to investigate the effect of the growth. Varieties of lettuce used for the analysis is 'Grand Rapids' lettuce. We cultivate the lettuce during five weeks, investigated the optimal nutrient supply methods and lettuce growth after seeding on 7, 14, 21, 27, 35 days, respectively. This finding represents that the Lettuce liquid of Yamajaki was the most pertinent culture liquid for cultivating Grand rapids. On the contrary, the minimum growth level was observed in use of Wondergrow Medium under experimental condition of 12 hr(on)/12 hr(off). 본 연구에서는 식물공장에서 주로 재배하는 상추를 대상으로 LED 조사 시간과 양액조성이 생장에 미치는 영향을 구명하기 위하여 수행하였다. 분석에 이용한 상추의 품종은 공시품종 청축면 상추이다. 상추는 분무경을 이용하여 5주간 재배하며, 정식 후 7, 14, 21, 27, 35일 경과 후 각각 생육조사 및 최적의 양액공급법에 대해 조사하였다. 조사 결과 청축면 상추에 가장 적절한 양액은 야마자키액이라고 판단하였으며, 광조건을 (12 hr(on)/12 hr(off))로 조절하거나 Wondergrow액으로 양액을 조성한 처리에서 생육이 가장 저조하였다.

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