• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.807-813
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• 2014

The Ag-impregnated activated carbon was produced from bamboo activated carbon by soaking method of silver nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. Soaking conditions are the variation of silver nitrate solution concentration (0.002~0.1 mol/L) and soaking time (maximum 24 h). The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20{\sim}850^{\circ}C$) and NO gas partial pressure (0.1~1.8 kPa). As results, Ag amounts are saturated within 2h, Ag amounts increased 1.95 mg Ag/g (0.2%)~ 88.70 mg Ag/g (8.87%) with the concentration of silver nitrate solution in the range of 0.002~0.1 mol/L. The specific volume and surface area of bamboo activated carbon of impregnated with 0.2% silver were maximum, but decreased with increasing Ag amounts of activated carbon due to pore blocking. In NO reaction, the reaction rate of impregnated bamboo activated carbon was retarded as compare with that of bamboo activated carbon. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.69l[BA(Ag)] and 80.5 kJ/mol[BA], 66.4 kJ/mol[BA(Ag)], respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.507-511
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• 2005

울돌목은 조류발전의 세계적인 최적지로 꼽히고 있으며 서해와 남해의 점이 지대로서 조류에 의해 해양 생물 군집의 대량 이동이 빈번한 곳이라 할 수 있다. 조류 발전 시설인 터빈의 가동은 물리적인 충격에 의해 해양 생물의 생태-생리 반응에 영향을 미칠 가능성이 있다. 네트를 이용한 1차 조사에서 터빈 가동에 의한 동물플랑크톤의 순 사망률은 $44.3\%$로 나타났다. 1차 조사 이 후 다이아프램 펌프를 이용한 조사 결과 중 출현 개체수가 높았던 조사에서 전체 동물플랑크톤의 순 사망률은 각각 $7.3\%,\;5.8\%$를 나타내었고, 요각류는 각각 $4.4\%,\;5.2\%$를 나타냈다. 물리적인 충격을 인위적으로 가한 실험에서 스트레스를 받은 요각류 Acartia hongi의 알 생산은 스트레스를 받지 않은 것보다 $1.8\~2.3$배 낮은 경향을 보였다. 본 조사에서 동물플랑크톤이 낮은 사망률을 보골 이유는 작은 크기의 생물이 우점하였기 때문이며 조사 결과에서 몸체가 비교적 단단하고 크기가 작은 요각류는 상대적으로 약한 부유유생보다 높은 생존율을 보였다. 울돌목 조사 해역에서 출현한 동물플랑크톤은 크기가 작아 터빈의 물리적인 충격에 의한 사망률은 낮을 수 있으나 순간적으로 강한 스트레스를 받는다면 재생산을 포함한 생리활동이 저하될 수 있음을 보였다. 네트 및 펌프를 이용한 조사 결과에서 네트에 의한 채집은 터빈의 영향뿐만 아니라 빠른 유속으로 인하여 네트가 받는 압력에 의해 생물체가 손상되는 양상이 높아 사망률이 높았던 것으로 보인다. 그러나 다이아프램 펌프는 생물 채집 시 오류를 최소화하는 장점은 있으나 채집의 장시간에 비해 매우 적은 생물량이 채집되는 단점을 보였다TEX>$96.5\%$에 미달하는 문제는 식물성 원료유로 제조한 고순도 바이오디젤과 혼합 사용하거나 감압 증류 공정을 통해 고농도의 폐식용유 바이오디젤을 제조하여 해결 가능하다. 대전시 신성동 소재의 음식점에서 수거한 폐식용유를 원료로 하여 생산한 바이오디젤의 차량 배출가스 실증 테스트 결과 경유 차량의 주 오염물질인 PM과 Soot 및 기타 오염물질의 배출량은 감소하였으나 NOx의 배출량은 약간 증가하는 것으로 나타났다구와 이해를 바탕으로 보존대책이 마련되어야 한다.되었다. 이런 모든 시편들을 각 탈염방법에 따라 탈염처리한 후 XRD와 SEM-EDS으로 분석한 결과 인철광과 침철광은 어떠한 변화도 보이지 않았고, 다만 적금광으로 동정된 시편만이 잔존하지 않았다. 철기 제작별 $Cl^-$ 이온 추출량과 탈염효과에 대한 비교 실험은 이온 크로마토그래피 분석 결과와 마찬가지로 단조 철제유물이 주조 철제보다 $Cl^-$ 이온을 많이 가지고 있었으며, 탈염 처리 후에는 $Cl^-$ 이온은 전혀 발견되지 않았다. 이상의 결과 $K_2CO_3$와 Sodium 용액은 탈염처리에서 가장 적합한 탈염처리 용액으로 알수가 있었으며 특히 어떠한 탈염 용액으로 유물을 처리한다 해도 철제유물에 생성된 부식물은 제거되지 않는다는 것을 알게 되었다. 따라서 보존처리자는 유물 표면의 부식 상태만을 보고 처리하기 보다는 철기제작물로 고려하여 처리하는 것이 필요하다. 또한 금속에 부식을 야기시키는 $Cl^-$ 이온과 부식물을 완전하게 제거하여 탈염처리를 하는 것이 유물 부식을 최대한 지연시킬 수 있는 것이라 생각된다.TEX>$88\%$)였다.(P=0.063). 결론: 본

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.847-860
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• 2020

This study was conducted into combustion characteristics and gases generated by the combustion of charcoal and agglomerated charcoal distributed in the domestic using a combustion chamber based on the average space per crater of a charcoal-grilled restaurant in South Korea. Each of the three types of charcoals and agglomerated wood charcoals was analyzed for fuel and combustion characteristics. In addition, the concentration changes of CO, CO₂, NO_x, and O₂ were measured for 20 minutes depending on ventilation. As a result, CO yield without ventilation was measured in the range of 1390 to 4703 ppm, and CO yield with ventilation decreases about 29.8% to 57.4%. CO₂ yield without ventilation was measured in the range of 1.34% to 2.42%, and CO₂ yield was about 44.1% to 53.6% when the emission was more than about 1.5% at 10 minutes. The NOx yield was divided into two cases where the NO_x yield was continuously increased because of incomplete combustion, emitted ranging from 29 ppm to 47 ppm, and where emission was constant after 1 minute in the range of 9 ppm to 18 ppm. The NO_x yield with ventilation tends to be similar to the without ventilation, and NO_x yield decreases up to 62.5%. Therefore, it could be used for health risk assessment with the simulation of the usage environment of charcoal and agglomerated wood charcoal.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.3
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• pp.144-149
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• 2016

The metal-impregnated activated carbon was produced from bamboo activated carbon by soaking method of metal nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use as de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20^{\circ}C{\sim}850^{\circ}C$) and NO gas partial pressure (0.1 kPa~1.8 kPa). As results, the specific volume and surface area of bamboo activated carbon impregnated with copper were decreased with increasing Cu amounts of activated carbon. In NO reaction, the reaction rate of Cu impregnated bamboo activated carbon[BA(Cu)] was promoted to compare with that of bamboo activated carbon[BA]. But the reaction rate of Ag impregnated bamboo activated carbon[BA(Ag)] was retarded. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.92[BA(Cu)], and 80.5 kJ/mol[BA], 48.5 kJ/mol[BA(Cu)], 66.4 kJ/mol[BA(Ag)], respectively.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.97-105
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• 2008

Nitrogen budgets in Korea in 2005 were estimated using a mass balance approach. Major nitrogen fluxes were divided into three sections: cities, agricultural area, and forest. Nitrogen inputs were chemical and biological fixation, dry and wet deposition, imported food and feed, while crop uptake, volatilization, denitrification, leaching, runoff, and forest consumption were nitrogen outputs. Non-point source(NPS) pollution budgets were also estimated by mass balance approach. Annual total nitrogen inputs budgets were 1,442,254 ton$\cdot$yr$^{-1}$, and outputs were 814,415 ton$\cdot$yr$^{-1}$. Approximately 19.4% of nitrogen input leaked to river and seawater as NPS pollution. It contains nitrogen input 21 percent more than the previous research in 2002. Especially the change of government plans affect nitrogen budget. As a result, in the output field, the whole nitrogen amount due to landfill reduce from 20 percent to less than 1 percent.

• Journal of ILASS-Korea
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• v.19 no.4
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• pp.155-166
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• 2014

This review will be concentrated on the spray characteristics of bioethanol and its derived fuels such as ethanol-diesel, ethanol-biodiesel in compression ignition (CI) engines. The difficulty in meeting the severe limitations on NOx and PM emissions in CI engines has brought about many methods for the application of ethanol because ethanol diffusion flames in engine produce virtually no soot. The most popular method for the application of ethanol as a fuel in CI engines is the blending of ethanol with diesel. The physical properties of ethanol and its derivatives related to spray characteristics such as viscosity, density and surface tension are discussed. Viscosity and density of e-diesel and e-biodiesel generally are decreased with increase in ethanol content and temperature. More than 22% and 30% of ethanol addition would not satisfied the requirement of viscosity and density in EN 590, respectively. Investigation of neat ethanol sprays in CI engines was conducted by very few researchers. The effect of ambient temperature on liquid phase penetration is a controversial topic due to the opposite result between two studies. More researches are required for the spray characteristics of neat ethanol in CI engines. The ethanol blended fuels in CI engines can be classified into ethanol-diesel blend (e-diesel) and ethanol-biodiesel (e-biodiesel) blend. Even though dodecanol and n-butanol are rarely used, the addition of biodiesel as blend stabilizer is the prevailing method because it has the advantage of increasing the biofuel concentration in diesel fuel. Spray penetration and SMD of e-diesel and e-biodiesel decrease with increase in ethanol concentration, and in ambient pressure. However, spray angle is increased with increase in the ethanol percentage in e-diesel. As the ambient pressure increases, liquid phase penetration was decreased, but spray angle was increased in e-diesel. The increase in ambient temperature showed the slight effect on liquid phase penetration, but spray angle was decreased. A numerical study of micro-explosion concluded that the optimum composition of e-diesel binary mixture for micro-explosion was approximately E50D50, while that of e-biodiesel binary mixture was E30B70 due to the lower volatility of biodiesel. Adding less volatile biodiesel into the ternary mixture of ethanol-biodiesel-diesel can remarkably enhance micro-explosion. Addition of ethanol up to 20% in e-biodiesel showed no effect on spray penetration. However, increase of nozzle orifice diameter results in increase of spray penetration. The more study on liquid phase penetration and SMD in e-diesel and e-biodiesel is required.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.513-513
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• 2009

최근 바이오디젤의 원료로 미세조류가 많은 관심을 끌고 있다. 미세조류는 물, 이산화탄소와 태양광을 이용해 광합성 성장이 가능하며, 지질(오일) 성분이 풍부하여 바이오디젤의 원료로 이용할 수 있다. 미세조류는 단위 면적당 오일 생산량이 곡물류의 50-100배 이상이며, 이산화탄소를 기질로 이용하므로 온실가스 직접 저감이 가능하다. 또한 배양시 비경작지나 황무지를 사용할 수 있으므로 기존 식용작물과 경쟁하지 않으며, 하수, 해수, 폐수 등 다양한 물자원을 이용할 수 있다. 본 연구에서는 고농도 $CO_2$에 내성을 지닌 Chlorella sp. KR-1을 대상으로 1 L 규모 기포탑 광생물반응기에서 균체 성장 및 지질(바이오오일) 합성에 대한 $CO_2$ 농도, 가스 공급속도, 질산염 농도 등 환경 및 영향 조건의 영향을 조사하였다. 가스 공급속도 0.4 L/min에서 $CO_2$ 농도를 0.03-20% 범위에서 조사하였을 때 최대 균체성장은 $CO_2$ 10%에서 관찰되었다. 균체내 지방산 함량은 $CO_2$ 농도 0.03%에서 가장 낮았고, 5-20% 범위에서는 $CO_2$ 농도 증가에 따라 감소하는 경향이 관찰되었다. 가스 공급속도를 0.2 L/min에서 0.8 L/min으로 증가시켰을 때 최대 균체농도는 0.6-0.8 L/min의 범위에서 관찰되었고, 생체내 최대 지방산 함량은 0.4 L/min에서 관찰되었다. Nitrate 농도 1-20 mM 범위에서 최종 균체농도는 nitrate 농도 증가에 따라 10mM까지 증가하였으나 그 이상에서는 증가하지 않았다. 반면 지방산 함량은 nitrate 농도 증가에 따라 감소하는 경향이 관찰되었다. 본 실험에서 얻은 최대 지방산 생산량은 1,100 mg/L이었으며, 주요 지방산은 C10:0(1.7%), C16:0(28.5%), C18:0(11%), C18:1n9c(25.9%), C18:2n6c(26.3%), C18:3n3(6.6%)이었다. 현재 100 L 규모 광생물반응기에서 석탄발전소 배가스($CO_2$ 12-15%, SOx 50ppm, NOx 100ppm)를 이용한 바이오오일 생산 실험이 진행 중이다.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.5
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• pp.39-46
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• 2020

This study evaluated the nitrogen oxide (NO_x) removal efficiency by air purification concrete blocks with titanium dioxide (TiO₂). The concrete in the mixtures had a 30% water:cement ratio, to which TiO₂ was added at 0%, 5%, and 10% of cement weight. The compressive strength reduction rate and removal efficiency of NO_x were investigated. The result of the compressive strength test in the study indicated that addition rate of TiO₂ did not lead to signifcant effect. In terms of the average removal efficiency of NO_x, mix No. 1 using a TiO₂ mixing ratio of 0% had a removal efficiency of 0.57% on average; thus, the removal effect w as not significant. For the other samples prepared by mixing, the average removal efficiencies for mix No. 2 (5% TiO₂) were 58.86% and 62.05% for normal and washing surface treatments, respectively, and those of sample No. 3 (10% TiO₂) were 59.94% and 67.61%. mixs No. 4 (5%) and No. 5 (10%), in which TiO₂ diluted with distilled water was sprayed onto the block surface, had an average NO_x removal efficiency of 61.72% and 68.48%, respectively. In terms of NOx removal efficiency, Mixs No. 3 and No. 5 with 10% TiO₂ were better than Mixs No. 2 and No. 4 with 5% TiO₂. In addition, analyzing the NO_x removal efficiency results from the fixing method, it was capable to apply mixing (washing) and the diluted spray methods. Therefore, it was found that the diluted spray method applied in this study can be employed in any manufacture of air purification concrete blocks.

• Journal of Ginseng Research
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• v.41 no.1
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• pp.23-30
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• 2017

Background: Ginsenoside Rg1 is a class of steroid glycoside and triterpene saponin in Panax ginseng. Many studies suggest that Rg1 suppresses adipocyte differentiation in 3T3-L1. However, the detail molecular mechanism of Rg1 on adipogenesis in 3T3-L1 is still not fully understood. Methods: 3T3-L1 preadipocyte was used to evaluate the effect of Rg1 on adipocyte development in the differentiation in a stage-dependent manner in vitro. Oil Red O staining and Nile red staining were conducted to measure intracellular lipid accumulation and superoxide production, respectively. We analyzed the protein expression using Western blot in vitro. The zebrafish model was used to investigate whether Rg1 suppresses the early stage of fat accumulation in vivo. Results: Rg1 decreased lipid accumulation in early-stage differentiation of 3T3-L1 compared with intermediate and later stages of adipocyte differentiation. Rg1 dramatically increased CAAT/enhancer binding protein (C/EBP) homologous protein-10 (CHOP10) and subsequently reduced the $C/EBP{\beta}$ transcriptional activity that prohibited the initiation of adipogenic marker expression as well as triglyceride synthase. Rg1 decreased the expression of extracellular signal-regulated kinase 1/2 and glycogen synthase kinase $3{\beta}$, which are also essential for stimulating the expression of $CEBP{\beta}$. Rg1 also reduced reactive oxygen species production because of the downregulated protein level of nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase 4 (NOX4). While Rg1 increased the endogenous antioxidant enzymes, it also dramatically decreased the accumulation of lipid and triglyceride in high fat diet-induced obese zebrafish. Conclusion: We demonstrated that Rg1 suppresses early-stage differentiation via the activation of CHOP10 and attenuates fat accumulation in vivo. These results indicate that Rg1 might have the potential to reduce body fat accumulation in the early stage of obesity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.357-364
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• 2021

The present study investigated the hydration properties and NO_x-removal performances of the cement pastes containing three different types of TiO₂. Two commercially available TiO₂ (P-25 and NP-400) and refined TiO₂ (GST) obtained from waste sludge were incorporated to cement paste at levels of 0, 5, 10, and 20 wt%. Isothermal calorimetry test results indicated that the TiO₂ incorporation induced a notable influence on the reaction kinetics of cement paste, showing the highest cumulative heat release in the samples containing P-25, followed by NP-400 and GST. Quantitative X-ray diffractometry as calculated by the Rietveld method identified that the incorporated TiO₂ promoted the formation of C-S-H, ultimately leading to the enhancement in the 28 day-compressive strength of cement pastes. As revealed by SEM/EDS analysis, the content of distributed Ti elements on the surface of the samples was in the order of P-25, GST, and NP-400. Regardless, the NO_x-removal performance was the highest in the sample containing P-25, followed by NP-400 and GST.