• 환경위생공학
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• 제14권4호
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• pp.85-92
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• 1999

Indoor air quality tends to be the dominant contributor to personal exposure because most people spend over 90% of their time indoors. For some contaminants, exposure to indoor air poses a potentially greater health threat than outdoor air exposures. Indoor nitrogen dioxide ($NO_2$) levels are mainly affected gas range, flue gas spillage, kerosene heaters, wood-burning appliances and cigarette smoke. In addition, indoor $NO_2$ levels are influenced by such house characterization as surface reaction and air exchange rate. In this study, the measurements of indoor and outdoor $NO_2$ concentrations were taken using identical protocols, and information was collected on housing characteristics using identical questionnaires in 14 houses out of 15 houses for daily 30 daily 30 days in Brisbane, Australia.The usage of gas range was the most contributing factor in indoor $NO_2$ concentration in relation to house characteristics. Average indoor and outdoor ratios of NO2 concentration in electronic and gas cooking houses were $0.6{\pm}0.1$ and $0.9{\pm}0.2$, respectively. The frequency distributions of $NO_2$ concentration in each house were approximately log-normal Geometric mean of indoor $NO_2$ concentrations of electronic and gas cooking houses for daily 30 days ranged from 2.5 ppm to 11.5 ppm with a mean 6.8 and from 4.7 ppm to 28.6 ppm with a mean 15.6 ppm, respectively. The $NO_2$ concentrations between electronic and gas cooking houses were significantly different (p<0.05). Since each house has different life-style and house characteristics, sampling interval to measure the $NO_2$ levels was recommended above 7 days.

• 한국환경보건학회지
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• 제30권3호
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• pp.221-229
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• 2004

We estimated decreasing rate of indoor air pollutants which are PM10 and $NO_2$ by the air cleaner in indoor environment. This study respectively examined concentration of PM10 and $NO_2$ two times in 34 sites located in Seoul and Kyung-gi Do from April to September in 2003. Sectional period was respectively divided for operating the air cleaner and non-operating the air cleaner. Moreover, questionnaire was executed to grasp physical characteristic of objective building and residential characteristic of residents by using method of self-entry. There was a trend that concentration of PM10 and $NO_2$ separated number of residents during operating period respectively decreased among indoor air. According to the existence of smoker in indoor, both concentration of PM10 and $NO_2$ during operating period decreased in each case, and according to existence of pets, both cases decreased concentration of pollutants by operating the air cleaner. We used Monte-Calro simulation to remove uncertainty and identify efficiency of eliminated pollutants such as PM10 and $NO_2$ by the air cleaner. Average efficiency of removal for PM10 and $NO_2$ were 61.84${\pm}$23.04% and 48.67${\pm}$18.03% respectively.

• 한국지구과학회지
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• 제42권2호
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• pp.149-163
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• 2021

본 연구에서는 광화학 대기질 모델인 CMAQ을 활용해 화력발전소 배출량 제거에 따른 O3 농도의 변화 특성을 분석하였다. 하동 화력발전소를 대상으로 주변 지역의 O3 농도 변화에 대한 발전소 배출량의 영향을 조사하기 위해 하동 화력발전소의 배출량 제거 전과 후의 CMAQ 수치 모의를 수행하였다. 수치 모의 결과 O3의 주요 전구 물질인 NOx (-18.87%)와 VOCs (-11.27%)의 농도가 감소한 반면에 O3 (25.24%)의 농도는 증가한 것으로 나타났다. 화력발전소 배출량 제거로 인한 NO와 O3 농도의 상대적인 변화를 비교해 본 결과 높은 음의 상관관계(R= -0.72)를 나타내는 것이 확인되었다. 이러한 결과는 O3의 농도 증가가 NO 농도 감소로 인한 O3의 적정 효과 완화로 설명 될 수 있음을 의미한다. 해당 지역의 O3의 농도 증가가 NO의 농도 감소에 주로 영향을 받은 이유는 해당 지역이 VOC-limited (i.e., NOx-saturated) 지역이기 때문으로 분석되었다. 이러한 결과는 특정 지역의 O3의 농도가 단순히 배출량의 증감에 따라 비례하게 나타나지 않을 수 있다는 것을 암시한다. 따라서 화력발전소 배출량 저감 조치로 인한 대기 중 O3 농도 개선 효과를 정확히 예측 및 평가하기 위해서는 지역 별 O3의 생성 및 소멸 기작에 대한 심도 있는 이해가 필요하다.

• 공업화학
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• 제18권2호
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• pp.173-177
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• 2007

PVA 농도, $AgNO_3$ 농도, IPA의 농도, 그리고 전자빔의 조사량 등의 다양한 조건에서 PVA 매트릭스에서 은입자를 생성하기 위하여 전자 빔을 이용하였다. PVA 농도, $AgNO_3$ 농도, 그리고 IPA의 농도가 증가하고 전자빔의 조사량이 증가함에 따라서 생성된 은입자의 분포도가 증가함을 알 수 있었다. 그리고 $AgNO_3$ 농도, IPA의 농도, 그리고 전자빔의 조사량은 은입자의 생성에 중요한 변수가 됨을 확인하였다. 이러한 결과들을 XRD, UV, 그리고 TEM 등으로 확인하였다. XRD로부터 생성된 입자가 은임을 확인하였다. 생성된 은입자의 분포 및 크기 등을 연구하기 위하여 UV와 TEM을 사용하였다.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.155-160
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• 2004

Permeation experiments of a commercial nanofiltration membrane (nominated as ESNA 1) were carried out with aqueous solutions of various single salts, that is, five chlorides (NH$_4$Cl, NaCl, KCl, MgCl$_2$ and $CaCl_2$), three nitrates $(NaNo_3,\;Mg(No_3)_2\;and\;Ca(NO_3)_2)\;and\;three\;sulfates\;((NH_4)_2SO_4,\;Na_2SO_4\;and\;MgSO_4)$. The experimental results showed that (1) the permeate volume flux of the ESNA 1 membrane increased and decreased with the growth of the applied pressure and the feed concentration of salts, respectively. The real rejection of ESNA 1 membrane to most single salts increased with the growth of the permeate volume flux. (2) The reflection coefficients of ESNA 1 membrane to chlorides, nitrates and sulfates are 0.97, 0.96 and 0.99, respectively. The solute permeability of most salts except for magnesium and calcium salts increased with the growth of feed concentration. (3) The sequence of the rejections of ESNA 1 membrane to anions is $R({SO_4}^{2-})>R(CI)>R(NO_3)$ at the same feed concentration. While the sequence of the rejections to cations is cataloged into two cases: $R(Na^+)>R(K^+)>R(Mg^{2+})>R(Ca^{2+})$ at the concentration of 10 mol/$m^3$ and $R(Mg^{2+})>R(Ca^{2+})>R(Na^+)>R(K^+)$ at the concentration of 100 mol/$m^3$. The separation capability of a NF membrane is usually affected by the electrostatic effect and the steric-hindrance effect. In this case, the electrostatic effect is the major factor at low concentration and the steric-hindrance effect is the major factor at high concentration. Both the specific sorption and the hydration also reasonably influenced the separation performance of NF membrane to salts.

• 대한한방부인과학회지
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• 제27권1호
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• pp.1-16
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• 2014

Objectives: The purpose of this study was to investigate the effects of Gardeniae Fructus Water Extract (GF) on the production of inflammatory mediators in RAW 264.7 cell treated with lipopolysaccharide (LPS). Methods: Gradeniae Fructus was extracted with distilled water (2,000 ml) for 2 hours. In order to evaluate cytotoxicity of GF, 3 - (4,5-dimethylthiazol-2-yl) - 2,5 - diphenyltetrazolium bromide (MTT) assay was performed. To investigate antiinflammatory effects, the concentration of nitric oxide (NO) was measured with No assay, calcium (Ca) was measured with Fluo-4 Ca assay, and cytokine was measured by Bio-Plex cytokine assay in RAW 264.7 cell. And when p-value is below 0.05, it is judged to have the significant difference statistically. Results: 1. GF did not show any cytotoxicity. 2. GF suppressed the production of NO and Ca at the concentration of 25, 50, 100 and $200{\mu}g/ml$. 3. GF suppressed the production of interleukin (IL)-$1{\beta}$, IL-10, IL-12p40, macrophage-colony stimulating factor (M-CSF), macrophage inflammatory protein (MIP)-$1{\beta}$ and keratinocyte chemoattractant(KC) at the concentration of 25, 50, 100 and $200{\mu}g/ml$. 4. GF suppressed the production of vascular endothelial growth factor (VEGF), granulocyte-colony stimulating factor (G-CSF) and monocyte cheomattractant protein (MCP)-1 at the concentration of 25, 50 and $100{\mu}g/ml$. 5. GF suppressed the production of granulocyte macrophage-colony stimulating factor (GM-CSF) and regulated on activation, normal T cell expressed and secreted (RANTES) at the concentration of 25 and $50{\mu}g/ml$. 6. GF suppressed the production of MIP-2 at the concentration of 50 and $100{\mu}g/ml$, and tumor necrosis factor (TNF)-${\alpha}$ at the concentration of 50 and $200{\mu}g/ml$. Conclusions: These results suggest that GF has anti-inflammatory effect and immuno-modulating activity.

• 산업기술연구
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• 제21권B호
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• pp.155-161
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• 2001

In this study, we analyzed the $NO_X$ removal efficiency and particle size distribution by the pulsed corona discharge process and investigated the effect of several process variables. The NO removal efficiencies and the particle characteristics were measured and analyzed as the function of initial concentrations of NO, $H_2O$, and $NH_3$, applied voltage, pulse frequency and residence time. As the frequency of applied voltage increases, or as the applied voltage increases or as the residence time increases, the NO removal efficiency increases. The change of initial $NH_3$ and $H_2O$ concentrations do not affect the NO removal efficiency significantly. The particle concentration and size increases with the increases of initial NO concentration, residence time and applied voltage.

• Journal of Acupuncture Research
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• 제23권4호
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• pp.115-121
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• 2006

Objectives : This study was designed to investigate the scavenging effect on Nitric Oxide of BUM. Methods : The scavenging effect on NO concentrations 2, 6, 12 and 24 hours after treatment with Vit C. and BUM at 1, 10, $100{\mu}g/ml$ were estimated. And those was compared with control group. Results : 1. The concentration of NO 2 hours after treatment with BUM at 1, 10, 1$100{\mu}g/ml$ were decreased compared with control group. 2. The conecntration of NO 6 hours after treatment with BUM at 1, 10, 1$100{\mu}g/ml$ were decreased compared with control group. 3. The concentration of NO 12 hours after treatment with BUM at 1, 10, $100{\mu}g/ml$ were decreased compared with control group. 4. The concentration of NO 24 hours after treatment with BUM at 1, $100{\mu}g/ml$ were decreased compared with control group. Conclusion : The scavenging effect of BUM on NO was dose-dependent.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제22회 KOSCI SYMPOSIUM 논문집
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• pp.133-138
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• 2001

In this study, quantitative nitric oxide concentration distributions are investigated in the laminar nonpremixed $H_2/N_2$ flames by laser-induced fluorescence (LIF). The measurements are taken in flames for different $N_2$ dilution ratios varying from 20${\sim}$80%, and fuel now rate is fixed as lslpm. The NO A-X (0,0) vibrational band around 226 nm is excited using a XeCl excimer-pumped dye laser. We applied same excitation line used in $CH_4$ premixed flame. Overall, NO concentration was rapidly decreased with $N_2$ addition and we could not measure the concentration any longer for $N_2$ dilution above 80%.

• 한국대기환경학회지
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• 제28권3호
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• pp.249-260
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• 2012

Monitoring of climate change and atmospheric environment by satellite measurements has been increased in recent years. In this study, nitrogen dioxide ($NO_2$) measurements from Ozone Monitoring Instrument (OMI) were compared with surface measurements over the Korean peninsula. $NO_2$ from OMI measurements showed high values and also showed seasonal variations such as high concentration in winter and low in summer over metropolitan areas while $NO_2$ concentration at national background station was low and did not clearly show seasonal variations. Surface measurements showed similar temporal and spatial variations to those of satellite measurement. The comparison between satellite measurements and surface measurements showed that the correlation between them was higher in urban area (r=0.64 at Seoul and r=0.63 at Daegu) than in national background stations (r=0.37 at Jeju) because the concentration in urban area was relatively high so that the variation of $NO_2$ concentration could be detected better than at national background stations by satellite. Satellite can effectively measure the emission and transport of pollutants with no limitations in spatial coverage.