• 한국태양에너지학회 논문집
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• 제38권1호
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• pp.13-24
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• 2018

As part of the "Carbon free Island 2030" policy, the local government of Jeju Island is currently working to reduce carbon through renewable energy supply. However, renewable energy is difficult to predict due to intermittent characteristics. If the share of renewable energy increase, it is difficult to plan of supply of electricity to grid due to that characteristic of renewable. In this paper analyze the fluctuation rate and the capacity credit of wind power and PV to find out how much wind power and PV contribute to supply of electricity of power system in Jeju. As a result mean value of variation rate of wind power and PV is about 3%, 5% and capacity credit is about 10% and 2% respectively.

• Nuclear Engineering and Technology
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• 제36권1호
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• pp.47-52
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• 2004

Recently, a new sintered pellet-type LiF:Mg,Cu,Na,Si TL detector which has a high sensitivity and good reusability, named KLT-300(KAERI LiF:Mg,Cu,Na,Si TL detector), was developed by the variation of the dopants concentrations and the parameters of the preparation procedure at KAERI (Korea Atomic Energy Research Institute). In this study, the thermoluminescent characteristics of the newly developed TL detectors were investigated. The sensitivity of the TL detector was compared with that of the TLD-100 by light integration. The dose linearity of the detector was tested from $10^{-6}$ Gy up to 30 Gy. The dose response was very linear up to 10 Gy and a sublinear response was observed at higher doses. The energy response of the detector was studied for photon energies from 20 keV to 662 keV. The result shows that a maximum response of 1.004 at 53 keV and a minimum response of 0.825 at 20 keV were observed. The reproducibility study for the TL detector was also carried out. The coefficients of variation for each detector separately did not exceed 0.016, and for all the 10 detectors collectively was 0.0054. Lower limit of detection for the detector was investigated at 70 nGy by the Harshaw 4500 TLD Reader and the residual signal of the TL detector was found to be $0.57\%$.

• Nuclear Engineering and Technology
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• 제41권6호
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• pp.841-848
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• 2009

A simple model to analyze non-linear density-wave instability in a sodium-cooled helically coiled steam generator is developed. The model is formulated with three regions with moving boundaries. The homogeneous equilibrium flow model is used for the two-phase region and the shell-side energy conservation is also considered for the heat flux variation in each region. The proposed model is applied to the analysis of two-phase instability in a JAEA (Japan Atomic Energy Agency) 50MWt No.2 steam generator. The steady state results show that the proposed model accurately predicts the six cases of operating temperatures on the primary and secondary sides. The sizes of three regions, the secondary side pressure drop according to the flow rate, and the temperature variation in the vertical direction are also predicted well. The temporal variations of the inlet flow rate according to the throttling coefficient, the boiling and superheating boundaries and the pressure drop in the two-phase and superheating regions are obtained from the unsteady analysis.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.337-343
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• 2021

In this work, self-absorption correction factor related to the variation of the composition and the density of soil samples were evaluated using the p-type HPGe detector. The validated MCNP5 simulation model of this detector was used to evaluate its Full Energy Peak Efficiency (FEPE) under the variation of the composition and the density of the analysed samples. The results indicates that FEPE calculation of low gamma ray is affected by the composition and the density of soil samples. The self-absorption correction factors for different gamma-ray energies which was fitted as a function of FEPEs via density and energy and fitting parameters as polynomial function for the logarithm neper of gamma ray energy help to calculate quickly the detection efficiency of detector. Factor Analysis for the influence of the element composition in analysed samples on the FEPE indicates the FEPE distribution changes from non-metal to metal groups when the gamma ray energy increases from 92 keV to 238 keV. At energies above 238 keV, the FEPE primarily depends only on the metal elements and is significantly affected by aluminium and silicon composition in soil samples.

• Steel and Composite Structures
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• 제24권2호
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• pp.265-276
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• 2017

Structures are designed in such a way that they behave in a nonlinear manner when subject to strong ground motions. Energy concepts have been widely used to evaluate the structural performance for the last few decades. Energy based design can be expressed as the balance of energy input and the energy dissipation capacity of the structure. New research is needed for multi degree of freedom systems (MDOFs)-real structures- within the framework of the energy based design methodology. In this paper, energy parameters are evaluated for low-, medium- and high-rise steel special concentrically braced frames (SCBFs) in terms of total energy input and hysteretic energy. Nonlinear dynamic time history analyses are carried out to assess the variation of energy terms along the height of the frames. A seismic energy demand spectrum is developed and hysteretic energy distributions within the frames are presented.

• Journal of Nutrition and Health
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• 제33권4호
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• pp.429-437
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• 2000

Contributions of specific foods to absolute intake and between-person variance in 13 nutrients were examined to develop a short food frequency questionnaire (FFQ) for the Korean elderly using dietary data collected by a semiquantitative FFQ with 96 food items. The contributions of specific foods to 90% absolute nutrient intake were measured by assessing their percentage to the total consumption of a nutrient by our samples(n=98). To assess the contribution of the foods to the between-person variance in intake of each specific nutrient, stepwise multiple regression was performed. Cumulative R2 served as the measure of contribution to variation in intake. The most important food source of absolute intake was rice for energy and protein. Important foods of between person variance contribution include bread for energy and pork for protein. Important foods of absolute and variance contribution of nutrient intake were similar for fat(noodles including jajangmyun and kalguksu), calcium(anchovy and milk) and vitamin A (carrot). The number of foods necessary to account for the variation in nutrient intake among older people in Korea differ considerably by nutrient: 18 - 43 and 8-26 foods were accounted for the respective 90 and 80% of absolute intake depending on nutrients. Carbohydrates and vitamin A and C had relatively a few major sources, thus may be assessed well by a small number of foods. Conversely, iron, potassium and B vitamins appear to need longer lists of foods. Fewer numbeer (6 - 12 and 4 - 9) of foods were required for the corresponding percentages of between-person variation for all nutrients. Depending on nutrients, 0.980-0.995 and 0.924-0.987 were respective correlation coefficients of nutrient intakes measured by 96 food items with those by lists of foods for 90% and 80% of absolute intake contribution. These findings suggest that an incomplete food list on the basis of its contribution to absolute and between person variation intakes may still be effective in discriminating among individuals. The results of this study may be useful in the design and use of dietary questionnaire.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1274-1275
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• 2011

This paper study effects that measured hamony occurence and changes of current and voltage according to variation of temperature of Far Infrared Ray Radiant Oven's room affect power quality.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 INTERNATIONAL SYMPOSIUM ON SOIL & GROUNDWATER ENVIRONMENT
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• pp.257-258
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• 2005

• Asian-Australasian Journal of Animal Sciences
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• 제16권6호
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• pp.830-836
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• 2003

The classical energy balance method was used to measure the apparent metabolisable energy (AME) of four batches of broiler starter and finisher diets produced by two commercial feed companies. The results showed there was little variation in protein content between batches, but NDF content varied from 13.3% to 15.5% between batches of diet. The batch variation in chemical composition differed between feed manufacturers. While there was no difference in AME and feed conversion ration (FCR) between batches of starter diets produced by company A, FCR and AME ranged from 1.76-1.94 (p<0.001) and 11.38-11.90 MJ/kg air dry (p<0.05), respectively, for diets produced by company B. Similar results were found in a second experiment. There was no difference in AME, dry matter digestibility (DMD) and FCR between batches for finishing diet produced by company B, but a large variation occurred for the finisher diets from company A (p<0.01), where the ranges of FCR, AME and DMD were 1.95-2.30, 10.5-12.3 (MJ/kg air dry) and 58-68%, respectively. FCR was correlated with AME. AME was negatively related to the content of fibre in the diet, but positively related to DMD. The preliminary results based on 24 samples showed that near infrared spectroscopy (NIR) has the potential to predict FCR, intake, AME and DMD of commercial broiler diets, with $R^2$ being 0.93, 0.89, 0.95 and 0.98, respectively. The standard error of cross validation was below 0.2 for AME and only 0.06 for FCR.

• 대한공간정보학회지
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• 제25권1호
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• pp.3-8
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• 2017

본 연구에서는 앙상블 중규모기후모델 weather research and forecasting(WRF)를 이용하여 2045년부터 2054년까지 21세기 중반의 기후변화에 대한 우리나라 미래 풍력자원 지도를 제작하였고 월별, 시간대별 자원변화를 검토하였다. 분석결과, 한반도상에서 강한 몬순 순환으로 인해 뚜렷한 월별 시공간 변동성이 해륙풍에 의한 시간대별 변동성보다 컸다. 풍력자원이 큰 강풍지역은 월마다 지역마다 다르게 나타났다. 즉 겨울철 북서계절풍(여름철 남서계절풍)이 주풍일 때 각각 강원산간과 해상 그리고 남서해안에서 자원이 많을 것으로 전망되었다. 최대풍과 최소풍은 1월, 9월에 각각 나타날 것으로 전망되었고, 시간대별로 내륙과 산간은 일중편차가 컸지만 연안지역은 편차가 작을 것으로 전망되었다. 이는 현재기후에 대한 기존분석결과와는 다소 차이가 있는 것으로, 이 연구에서 생산된 미래 풍력자원 지도는 향후 기후 변화 가능성이 큰 지역의 시공간적 풍황을 감안하여 풍력단지 입지 선정 및 풍력운영을 위한 장기계획 마련에 있어서 유용한 자료가 되리라 기대된다.