• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1668_1669
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• 2009

보일러 연료제어의 근본 목적은 보일러 입력에너지와 출력에너지 간의 평형을 유지하는 것이다. 보일러 출력에너지는 유출증기가 가지고 나가는 총 에너지에 해당하고, 입력에너지는 보일러에 공급되는 연료의 연소에 의해 발생하는 열 에너지에 해당한다. 보일러 연료의 공급과 연소제어에는 여러 가지 변수가 상존하고 있으며, 이 변수들의 영향을 잘 반영하여 필요한 연료량을 실시간으로 정확히 제어하는 것이 결코 쉬운과제가 아니다. 석탄연소발전소의 주연료는 당연히 석탄이며 석탄을 입자가 매우 적은 미분탄으로 가공해서 연소하는 '미분탄 연소방식'을 많이 사용한다. 석탄의 공급과 연소에 영향을 미치는 인자로는 도입 탄종 변화에 따른 발열량, 수분함유량, 기타 성분의 변화가 있으며, 미분기 특성 및 성능변화, 연소용 공기 공급상태 변동에 따른 연소상태변화 등을 들 수 있다. 이 논문에서는 국내 석탄화력 발전소에서 가장 많이 사용하고 있는 전형적인 보일러 연료제어 전략과 알고리듬을 분석하였으며, 여기서 습득한 이론을 바탕으로 내년에는 실제 발전소에 적용할 연료제어로직을 설계할 예정이다.

• Korean journal of food and cookery science
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• v.23 no.6
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• pp.947-953
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• 2007

This study was conducted to promote the utilization of fish paste with added lotus leaf powder as a food. The tested concentrations of lotus leaf powder were 0, 0.5, 1, 1.5, and 2%. All the samples of fish paste with added lotus leaf powder had 37% water content. For the Hunter color values, the L, a and b values of the fish paste decreased with increasing concentrations of lotus leaf powder. And the folding test presented a good score(AA). In the texture meter test, the gumminess, and brittleness decreased according to increasing concentrations of lotus leaf powder. However, the hardness, cohesiveness, and springiness of the fish paste were not significantly changed by the addition of lotus leaf powder. In the sensory evaluation, the lotus leaf flavor, hardness, and adhesiveness increased as the concentrations of lotus leaf powder increased. The fish paste with 0.5% lotus leaf powder(0.5 LP) showed the highest acceptance scores in terms of pleasant taste and springiness. The fish paste with 0.5% lotus leaf powder(0.5 LP) also showed the highest acceptance scores for appearance, flavor, taste, texture, and overall quality. Therefore, the results suggest that lotus leaf powder can be applied to fish paste to increase its quality and functionality.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.91-97
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• 2013

The input parameters of scattering models for computing the backscattering coefficients of earth terrains are mainly soil moisture and surface roughness. The backscattering coefficients of soil surfaces are more sensitive to surface roughness than soil moisture. In this study, we propose a precise measurement method for roughness parameters and analyze measurement errors. We measured surface roughness using a pin-board profiler(1 m, 0.5 cm interval) and a laser profiler(1 m, 0.25 cm interval). The measurement differences between two profilers in an average sense are 0.097 cm for root-mean-square (RMS) height and 1.828 cm for correlation length. The analysis of the correlation functions and relative errors shows that the laser measurements are more stable than the pin-board measurements. The differences of the calculated backscattering coefficients using a surface scattering model between pin-board and laser profiler measurements are less than 1 dB.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.1
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• pp.22-28
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• 2008

This study was performed to aid promotion of fish paste containing Lycii fructus powder as a food. The tested concentrations of Lycii fructus powder were 0, 1, 3, 5, and 7%. All the fish paste samples had 37% water content. The L values of the samples decreased as the concentration of Lycii fructus powder increased(p<0.001), and the a- and b-value increased(p<0.001). All samples with 3 mm of thickness had good flexibility and did not break even after four times of folding. In texture meter tests, the cohesiveness increased, but gumminess and brittleness decreased according to increasing concentration of Lycii fructus' powder. In the sensory evaluation, scores for color, flavor, pleasant taste, hardness and adhesiveness increased with increasing powder concentration; however oily taste was decreased. The 3% Lycii fructus powder sample had the highest acceptance scores in terms of appearance, flavor, taste, texture and overall acceptability. The results suggest that Lycii fructus powder can be applied to fish paste for both quality and functionality.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.32-39
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• 2008

This paper presents the soil ionization phenomena and the parameters with the transient characteristics of model grounding system under lightning impulse voltages. lonization properties of dry and wet sands were investigated by using two test cells of concentric cylindrical electrode system with different dimensions. As a result non-linear electrical behavior of sand under high impulse voltage is caused by ionization process. The transient impedance of sand depends not only on the water content but also on the magnitude of applied impulse voltages. The grounding impedance is decreased with increasing the water content and the magnitude of a lied voltages. The results resented in this paper will provide useful information on the design of high performance grounding systems against lightning surge.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.343-346
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• 2004

가스절연개폐기의 절연물로 사용되는 에폭시가 흡습환경에 노출될 경우 절연내력은 급격히 저하된다. 에폭시 절연물에 함유되어 있는 수분은 어느 일정 온도에서는 가스 내 수분과 평형을 이루고 있지만 온도변화에 따라 수분은 이동되며 또 고전압 인가 시 절연체 표면은 열화 되어 장기간에 걸쳐 침식과 함께 Treeing 현상을 유발시킨다. 본 연구에서는 에폭시 절연물의 절연특성에 미치는 수분의 영향을 파악하기 위하여 실 계통에서 사용된 제품에 대해 AC 내전압시험 및 재료분석을 시행하였다. 분석결과, 표면의 파괴전압은 주수량에 따라 건조섬락전압의 최대 1/5까지 저하되었다.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.187-188
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• 2014

초음파 전파 매개물은 초음파의 손실 없는 투과력을 위한 1차적인 목적 이외에 피부위에서 탐촉소자의 부드러운 이동을 위한 부가적인 목적이 있다. 본 연구는 제형이 다른 진단초음파 전파매개물이 갖는 피부 윤활성, 피부 보습성, 건조속도 등의 초음파 매개물의 특징을 측정하고 비교하였다. 마찰계수는 점도가 높을수록 높았으며 제제의 건조속도는 고분자 수화젤이 가장 높았다. 오일 함유량이 많을수록 수분증발이 나타나지 않았다. 피부수분함량에서는 저점도 에멀전이 높은 수분함량을 나타냈으며 수분함량 감소 정도가 가장 완만히 나타났다. 오일성분을 적절히 사용한 에멀전 형태의 초음파 전파매개물은 피부 보습효과, 피부 유연작용의 피부 건강측면과 피부-탐촉소자간의 피부 윤활성면에서 효과적인 제형임을 알 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.67-67
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• 2004

다공성 물질을 건조하거나 습한 환경에 노출시키면 열과 수분이 외부로 전달된다. 열 및 수분 전달로 인한 은도 및 습도의 변화는 물질 체적을 변화시켜 습열 응력을 유발시킨다 즉 다공성 제품의 품질은 외양뿐만 아니라 건조 공정 시의 온도, 수분함유량, 응력, 변형률 등의 공정변수에 크게 영향을 받는다. 최근까지도 다공성 물질의 생산 공정은 다수의 공정변수를 갖는 복합공정이기 때문에 이들의 영향을 정량적으로 평가하는 것은 매우 까다로워 현장 경험에 기초한 기술자의 노하우에 의존해 왔다.(중략)

• Culinary science and hospitality research
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• v.15 no.3
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• pp.213-224
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• 2009

The present study analyzed the sensory characteristics of fish stock, which is the base of seafood sauce, such as moisture, ash, pH, mineral, free amino acid and sensory properties according to the additions of white wine in order to improve its taste and nutrition using its effect on the minerals and free amino acid of fish bones. As white wine was added more, water and ash contained in fish bones increased and pH decreased. When 11.5% of white wine was added, minerals such as calcium, potassium and magnesium showed the highest contents; and when 7.7% of white wine was added, sodium and phosphorus showed the highest contents. The total amount of free amino acid and general acceptance were highest when 7.7% of white wine was added. The results of this study as presented above suggest that 7.7% of white wine is most appropriate in preparing fish stock.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.157-165
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• 2010

In this study, the antioxidative effects, inhibitory effects on tyrosinase and elastase of Rhododendron brachycarpum D. Don extracts were investigated. And the moisturizing effect of cream containing R. brachycarpum D. Don extract were investigated by clinical trial. The ethyl acetate fraction of R. brachycarpum D. Don extract (1.83 ${\mu}g/mL$) showed the most prominent the free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$). Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of R. brachycarpum D. Don extracts on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The 50 % extract fraction (0.064 ${\mu}g/mL$) showed the most prominent ROS scavenging activity. The protective effects of extract/fractions of R. brachycarpum D. Don on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The R. brachycarpum D. Don extracts suppressed photohemolysis in a concentration dependent manner (1 ~ 10 ${\mu}g/mL$). The inhibitory effects ($IC_{50}$) of R. brachycarpum D. Don extracts on tyrosinase were determined with ethyl acetate fraction of R. brachycarpum D. Don extract (70.5 ${\mu}g/mL$) and aglycone fraction of extract (122.40 ${\mu}g/mL$). The inhibitory effects ($IC_{50}$) on elastase were determined with ethyl acetate of R. brachycarpum D. Don extract (43.50 ${\mu}g/mL$) and aglycone fraction of extract (20.73 ${\mu}g/mL$). The cream containing the ethyl acetate fraction of R. brachycarpum D. Don extracts was formulated for skin hydration effect and transepidermal water loss (TEWL). The cream containing R. brachycarpum D. Don extract was applied to the right lower arm. After 180 min, the water contents in skin were increased by 1 ~ 4 % than the placebo cream. And TEWL of parts was decreased as 7.7 $g/m^2h$ (experimental cream) and 8.9 $g/m^2h$ (placebo cream) respectively. These results indicate that extract/fractions of R. brachycarpum D. Don can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And inhibitory activity on tyrosinase of the aglycone fraction could be applicable to new functional cosmetics for whitening and anti-wrinkle products. Also the increase of skin hydration of the cream containing extract could be applicable to new functional cosmetics for antiaging.