• 한국응용과학기술학회지
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• 제29권4호
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• pp.570-576
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• 2012

본 연구에서는 무격막식 전기분해 처리된 해수를 산화제로하는 NO 산화반응의 특성에 대해 실험적으로 살펴보았다. 폐순환 정전류 전기분해 시스템을 통해전해 시간이 길어질수록 전해수의 유효 염소농도와 온도, 염소산 이온의 비율이 증가함을 확인하였다. 전해수가 채워진 버블링 반응기에서 전해수의 유효염소농도와 온도에 비례하여 $NO_2$로 산화되는 NO의 양이 증가하였다. 또한 산화되어 생성된 $NO_2$는 전해수에 용해되어 $HNO_3{^-}$ 이온으로 존재함을 확인하였다.

• International Journal of Vascular Biomedical Engineering
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• 제1권2호
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• pp.13-19
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• 2003

Endothelial release of nitric oxide (NO) contributes to the regulation of vascular tone by inducing vascular relaxation. To estimate the blood flow-dependent nitric oxide level and half-life (T1/2) of nitric oxide in vivo state, we investigated the change of aortic NO currents during the change of aortic blood flow rate using NO-selective electrode system and electromagnetic flowmeter in the aorta of anesthetized rats. Resting mean aortic blood flow rate was $49.6{\pm}5.6ml/min$ in the anesthetized rats. NO currents in the aorta were increased by the elevation of blood pressure and/or blood flow rate. When the aortic blood flow was occluded by the clamping, aortic NO currents were decreased. The difference of NO concentration between resting state and occluded state was $1.34{\pm}0.26{\mu}M$ (n=7). This NO concentration was estimated as blood flow-dependent nitric oxide concentration in the rats. Also, while the aortic blood flow was occluded, NO currents were decreased with exponential pattern with $12.84{\pm}2.15$ seconds of time constant and $7.70{\pm}1.07$ seconds of half-life. To summarize, this study suggested that blood flow-dependent NO concentration and half-life of nitric oxide were about $1.3{\mu}M$ and 7.7 seconds, respectively, in the aorta of anesthetized rats. The nitric oxide-selective electrode system is useful for the direct and continuous measurement of NO in vivo state.

• 한국의류학회지
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• 제28권7호
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• pp.873-881
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• 2004

This research was aimed to investigate the effect of enzyme and the addition of chelators on rotting of the Kenaf bast. Enzyme rotting was effective only when the chelators were added with the enzyme. EDTA was a more effective chelator than oxalic acid under 1% concentration. There was no difference in the rotting effect under different enzyme concentration levels, and under different treatment time and temperature. Therefore, it was found that enzyme rotting can be carried out with low enzyme concentration(0.125%) at room temperature. Retting time can be shortened when higher enzyme concentration and higher temperature are applied. Cellulose I structure of kenaf fiber did not change after enzyme rotting, and different enzyme concentration did not affect the crytallinity structure. Non-cellulosic matters such as hemicellulose, lignin, and pectin were present in the descending order in the enzyme rotted kenaf fiber, and there were no differences in their amounts due to enzyme concentration levels. There was no difference in the dyeabilities of kenaf fiber rotted with different enzyme concentration levels. Enzyme rotted kenaf fiber showed better cyeability when pectin, lignin, and hemicellulose were removed.

• 한국동물생명공학회지
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• 제38권3호
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• pp.121-130
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• 2023

Background: Coating a culture plate with molecules that aid in cell adhesion is a technique widely used to produce animal cell cultures. Extracellular matrix (ECM) is known for its efficiency in promoting adhesion, survival, and proliferation of adherent cells. Gelatin, a cost-effective type of ECM, is widely used in animal cell cultures including feeder-free embryonic stem (ES) cells. However, the optimal concentration of gelatin is a point of debate among researchers, with no studies having established the optimal gelatin concentration. Methods: In this study, we coated plastic plates with gelatin in a concentration-dependent manner and assessed Young's modulus using atomic force microscopy (AFM) to investigate the microstructure of the surface of each plastic plate. The adhesion, proliferation, and differentiation of the ESCs were compared and analyzed revealing differences in surface microstructure dependent on coating concentration. Results: According to AFM analysis, there was a clear difference in the microstructure of the surface according to the presence or absence of the gelatin coating, and it was confirmed that there was no difference at a concentration of 0.5% or more. ES cell also confirmed the difference in cell adhesion, proliferation, and differentiation according to the presence or absence of gelatin coating, and also it showed no difference over the concentration of 0.5%. Conclusions: The optimum gelatin-coating for the maintenance and differentiation of ES cells is 0.5%, and the gelatin concentration-mediated microenvironment and ES cell signaling are closely correlated.

• 보존과학회지
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• 제29권3호
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• pp.197-207
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• 2013

이산화질소($NO_2$) 농도에 따른 전통직물의 손상특성을 정량적으로 확인하고자 가스 열화실험을 수행하였다. 견, 면, 모시, 삼베의 무염색직물 시편, 천연염색(적색, 황색, 청색, 흑색)직물 시편을 온도 $20^{\circ}C$, 습도 50%, 환기횟수 1/hr 조건의 가스부식시험기 챔버 내에서 $NO_2$ 0.01, 0.1, 1, 10, 100, 1000 ppm 농도로 각각 1일 노출한 후 광학적, 화학적, 물리적 측정방법으로 손상도를 평가하였다. 이 결과, 전통직물은 $NO_2$ 1 ppm/day에서 색차 증가, 변퇴색등급 저하가 나타났고, 10 ppm/day에서 질산이온($NO_3{^-}$) 농도 증가, pH 감소, 카르보닐기 및 C-$NO_2$ 작용기 증가가 나타났으며, 100 ppm/day에서 인장강도 감소가 나타났다. 또한 무염색직물에서는 견, 삼베의 색차 증가, 삼베의 $NO_3{^-}$ 증가 및 인장강도 감소가 크게 나타났고, 염색직물에서는 청색, 황색직물의 색차 증가, 황색직물의 $NO_3{^-}$ 증가, 삼베, 모시의 인장강도 감소가 크게 나타났다. 이를 통해 $NO_2$에 의한 전통직물의 광학적, 화학적, 물리적 손상농도는 각각 1 ppm/day, 10 ppm/day, 100 ppm/day임을 도출하였다.

• 대한기계학회논문집B
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• 제33권7호
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• pp.486-494
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• 2009

One-dimensional modeling of $CH_4$/air premixed flame was conducted to validate the heat loss model and investigate NOx formation characteristics in the postflame region. The predicted temperature and NO concentration were compared to experimental data and previous heat loss model results using a constant gradient of temperature (100 K/cm). The following conclusions were drawn. In the heat loss model using steady-state heat transfer equation, the numerical results using the effective heat loss coefficient ($h_{eff}$) of $1.0\;W/m^2K$ were in very good agreement with the experiments in terms of temperature and NO concentration. On the other hand, the calculated values using the constant gradient of temperature (100 K/cm) were lower than that in the experiments. Although the effects of heat loss suppress NO production near the flame region, a significant difference in NO concentration was not found compared to that under adiabatic conditions. In the postflame region, however, there were considerable differences in NO emission index as well as the contribution of NO formation mechanisms. In particular, in the range of ${\phi}\;{\geq}\;0.8$, the prompt NO mechanism plays an important role in the NO reduction under the adiabatic condition. On the other hand, the mechanism contributes to the NO production under the heat loss conditions.

• 대한기계학회논문집B
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• 제27권5호
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• pp.561-568
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• 2003

An experiment using high preheated air in a turbulent non-premixed flame was performed to investigate the effects of high preheated air on the combustion characteristics. Combustion using high preheated and diluted air with flue gas is a new technology which enables NO emission to be reduced. In this study, Na was used as diluent and propane as fuel. Combustion characteristics, especially the distributions of the flame temperature, NO concentration and OH radical intensity were examined under the condition of 300 K, 600 K, 1000 K in terms of the combustion air temperature, and also under the condition of the dilution level from 21% to 13% in terms of oxygen concentration. As the preheated air temperature increased, it appeared that the flame length became shorter, maximum flame temperature increased, the reaction region moved to upstream, and NO concentration increased, but the flame temperature's fluctuation was reduced. In opposite, it was shown with decrement of oxygen concentration at the maximum temperature that both maximum value and the gradient of the flame temperature decreased, and NO emission also decreased considerably, but its fluctuation became larger, being inclined to be unstable.

• 한국환경보건학회지
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• 제26권4호
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• pp.134-140
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• 2000

The increase in traffic is a worldwide phenomenon. In Korea, it has been increased by 20% per annual in recent 1990’s and approximately 10 millions cars had been registered until 1997. This traffic could easily affect and contribute the local outdoor air quality(QAQ) concerned. The QAQ in highway in one of the examples and the subject in this study. The seoul tollgate located at the north-end of Keypngbu Highway was selected for the study. In case of highway tollgate, the local air pollution could be directly affected by the traffic to approach, wait and start the tollgate. Nitrogen dioxide (NO$_2$) concentration exceeded the EAQS(Environmental Air Quality Standards), but overall indoor air quality was a little better than the outdoor air quality. The measured TSP concentration was much higher than that of the EAQS. To apply a management to a air quality problem of Seoul tollgate, it was predicted air quality with traffic volume and weather condition. It was calculated NO$_2$ emission with traffic volume and predicted in and out of booth by CALINE3 at the Seoul tollgate. To make a comparison between measured and predicted concentration, the prediction was good. It was shown that NO$_2$ concentration was high in the morning at the from Seoul direction and in the evening at the to Seoul direction. it was thought that NO$_2$ concentration variation was reflected according to the traffic volume.

• The Korean Journal of Ecology
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• 제20권6호
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• pp.397-403
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• 1997

The monoterpenes and sesquiterpenes are analysed in the leaf and stem of Chrysanthemum boreale using gas chromaltography-mass spectrometry (GC-MS). The total amount of sesquiterpenes are always higher than monoterpenes in both leaf (2.0-3.4 times) and stem (1.6-8.3 times). The mono- and sesquiterpenes yields of the leaf are higher than the stem. There was no significant difference among the leaf developmental stages, while those of stem were varied. Seventeen monoterpenes and 9 sesquiterpenes compound in this plants comprised more than 5% of the mean total monoterpenes and the total sesquiterpenes in each dates. Among leaf monoterpenes, the concentration of (+)-Limonene and unknown compound no. 13 (Retention time, R.T.=17.28) varied significantly during leaf growing season, and the concentrafion of unknown compound no. 7 (R.T.=35.04) and no. 9(R.T.=35.71) varied in the leaf sesquiterpenes. Similarly the results from the leaf, the concentration of five monoterpenes in stem also varied significantly during maturing period, and much varied in seven compounds of stem sesquiterpene. The major sesquiterpenes of leaf and stem were ${\alpha}-Humulene$ and compound no. 2(R.T.=26.19).

• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.1-3
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• 2013

The premixed combustion system applying exhaust gas recirculation was investigated to achieve the low pollutant emission and the high thermal efficiency. In this study, it was studied the effects of EGR on the thermal efficiency, $NO_x$ and CO emissions with various EGR ratios and equivalence ratios. As results, when equivalence ratio was increased, thermal efficiency increased and $NO_x$ and CO concentration increased. When EGR was applied, $NO_x$ and CO concentration decreased and thermal efficiency increased. Especially, in the case of 15% of EGR ratio at 0.85 of equivalence ratio, $NO_x$ and CO concentration will be a smaller than these of a current operating condition of the boiler and thermal efficiency was about 1.7% higher.