• International Journal of Automotive Technology
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• 제7권6호
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• pp.653-658
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• 2006

The enormous increase in the use of fossil energy sources throughout the world has caused severe air pollution and a depletion of energy. Besides, it seems very difficult to comply with the upcoming stringent emission standards in vehicles. In order to develop low emission engines, research on better qualified fuels as alternative fuels to secure high engine performance becomes a more important issue than ever. Since sulfur contained in diesel fuel is transformed in sulfate-laden particulate matters when a catalyst is applied, it is necessary to provide low sulfur fuels before any Pt-based oxidation catalysts are applied. But the excessive reduction of sulfur levels may cause the lubricity of fuel and engine performance to degrade. In this aspect, biodiesel fuel derived from rice bran is applied to compensate viscosity lost in the desulfurization treatment. This research is focused on the performance of an 11,000cc diesel engine and the emission characteristics by the introduction of ULSD(Ultra Low Sulfur Diesel), BD20(Diesel 80%+Biodiesel 20%) and a diesel oxidation catalyst, where BD20 is used to improve the lubricity of fuel in fuel injection systems as fuel additives or alternative fuels.

• 한국식품과학회지
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• 제8권4호
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• pp.201-206
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• 1976

한국인삼(韓國人蔘)의 뿌리중(中)의 ether가용성분중(可溶成分中)에서 불령화물(不齡化物)을 검출(檢出)한다음에 Thinlayer chomatography법(法)과 Gas liguid Chromatography법(法)에 의해서 Sterol의 성분(成分)을 검출(檢出)하였다. 그 결과인삼중(結果人蔘中)에서 stigmasterol이 반치폭법(半値幅法)에 의하면 15.39%. 그리고 planimetry법(法)에 의하면 13.92%이었고 ${\beta}-Sitosterol$은 반치폭법(半値幅法)에 의하면 77.87% 그리고 planimetry법(法)에 의하면 82.72%로 가장 함량(含量)이 높았고 Campesterol은 반치폭법(半値幅法)에서는 6.74% 그리고 Planimetry법(法)에서는 4.36%가 됨을 알수 있다.

• 한국토양비료학회지
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• 제46권1호
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• pp.32-39
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• 2013

The relationship between relative water contents of lettuce leaves and biochemical activities in lettuce was examined in this study to explore an adaptation response of lettuce to water stress from soils. Soil water contents and relative water contents of leaves were positively related to show $R^2$=0.8728. Hydrogen peroxide contents of leaves rapidly increased with reduction of soil water content, whereas soluble protein contents and dry matters rapidly decreased. And chlorophyll a and b contents of leaves decreased with increase in carotenoid content. Furthermore, the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR) increased dramatically, and mRNA transcript levels of APX, MDHAR and DHAR also increased. Relationship of relative water content of lettuce leaves to hydrogen peroxide, to ascorbate peroxidase activity, to dehydroascorbate reductase activity, and to monodehydroascorbate reductase activity was shown to be positively correlated. It is highly plausible from this study that these enzyme activities could be developed as an indicator of water states in soils.

• 상하수도학회지
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• 제31권3호
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• pp.257-262
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• 2017

Several disposal processes for waste sludge from wastewater treatment plants such as landfill, ocean dump, incineration, reuse as fuels or fertilizers are practiced. However, ocean dumping is prohibited by international treat. New constructions of landfill sites or incineration facilities are limited by NIMBY and reuse processes are still suffering from low energy yield. Therefore, development of alternative processes for sludge disposal are currently needed. In this study, alternative technique for sludge solubilization using HVI (high voltage impulse) was suggested and verified experimentally. Sludge solubilization was carried out for 90 minutes using HVI discharge with peak voltage of 16 kV and pulse duration for 40 microsecond. About 3~9 % of MLSS and MLVSS concentration were reduced, but the soluble COD, TN, TP of the sludge increased to 372 %, 56 % and 102 % respectively. It indicates that the flocs and/or cells of the sludge were damaged by HVI. These resulted in flocs-disintegration and cells-lysis, which means the internal matters were bursted out of the flocs as well as the cells. Thus, electrical conductivity in bulk solution was increased. All of the results verified that the HVI could be used as an alternative technique for sludge solubilization processes.

• 한국토양비료학회지
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• 제48권6호
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• pp.602-609
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• 2015

In order to enhance a biogas production by the hydro-thermal pre-treatment of piggery manure, the effects of hydro-thermal reaction temperature at thermal hydrolysis of piggery manure on the methane potential and anaerobic biodegradability of thermal hydrolysate were analyzed. The increase of hydro-thermal reaction temperature from $170^{\circ}C$ to $220^{\circ}C$ caused the enhancement of hydrolysis efficiency, and most of organic matters were present in soluble forms. However, the methane potentials ($B_u-TCOD$) of hydrolysate were decreased from 0.239 to $0.188Nm^3kg^{-1}-TCOD_{added}$ by increasing hydro-thermal reaction temperature from $170^{\circ}C$ to $220^{\circ}C$, and also the anaerobic biodegradability (DTCOD) decreased from 74.6% to 58.6% with increase of hydro-thermal reaction temperature. The increase of hydro-thermal reaction temperature from $170^{\circ}C$ to $220^{\circ}C$ resulted in the decrease of easily biodegradable organic matter content, while persistent organic matter contents increased.

• 유기물자원화
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• 제9권3호
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• pp.55-69
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• 2001

수산가공폐수슬러지를 이용한 고품질의 퇴비생산을 위하여 현장 퇴비화공장에서 슬러지와 가축분의 혼합 비율에 따른 퇴비화 과정중의 온도는 모든 처리에서 퇴비화 3~5일간 급격히 상승하여 최고온도에 도달하였으며 그후 서서히 감소하는 경향이었다. 퇴비화 19일후 하강온도가 $40{\sim}50^{\circ}C$되었을 때를 1차 퇴비화 종료시점으로 판단하고 1차 뒤집기를 실시하고 후숙을 시켰으며 그후 퇴비화조내의 온도가 다시 상승하였다. 그후 2차 및 3차 뒤집기를 실시하였으나 온도의 상승폭이 작아 퇴비화가 완료된 것으로 판단하였다. 그리고 퇴비화과정중 온도는 슬러지 첨가율이 높을수록 높았다. 퇴비화 종료시점에서의 퇴비중 총 탄소함량은 퇴비화 초기에 비해 약 4.5~8.0% 감소하였고, 그 감소폭은 수산가공폐수슬러지의 첨가율이 높을수록 증가하였다. 퇴비화과정 중 유기물중 ether추출물질, resins 및 hemicellulose함량은 각각 약 35~77%, 32~69% 및 19~30%감소하였으나, 수용성 polysaccharides함량은 별 변화가 없었고, cellulose, lignins 및 미동정태 유기물함량은 약간 증가하였다. 퇴비화 종료시점에서의 총 질소, amino sugar태 및 amino acid태 질소함량은 퇴비화재료에 비해 각각 약 20~42%, 11~40% 및 23~65% 감소하였다. 퇴비화과정 중 humic acid함량은 별 변화가 없었으나, fulvic acid함량은 퇴비화가 진행될수록 감소하여 전체 humus 중 humic acid가 차지하는 비율이 증가하였다. 수산가공폐수 슬러지의 퇴비화과정 중 시기별 무우, 배추 및 오이의 발아율 및 뿌리 생장율을 조사한 결과 모든 처리에서 발아율은 퇴비화 30일 이후에는 90%이상으로서 완숙퇴비기준치 이상이었고, 뿌리생장율도 30일 이후에는 대조구와 비슷하였으며 퇴비화 30일 이후에는 각 처리 조건 및 시기별 별 영향이 없었다.

• 원예과학기술지
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• 제19권4호
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• pp.521-525
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• 2001

배추 '노랑' 품종을 이용하여 수확 후 관행예건 및 MA 저장이 배추 저장성 및 품질에 미치는 영향을 조사하였다. 수확한 배추는 2일간 관행예건한 후 0.05mm MA 포장과 무포장하여 $4^{\circ}C$에 저온 저장하였다. 배추는 MA 포장한 배추가 무포장한 배추보다 Hunter L과 b 값의 변화가 완만하며, 예건처리구의 L과 b 값이 통계적 유의성은 없으나 포장과 무포장 처리구 모두 변화가 적었다. 배추의 생체중 감소는 저장중 지속적으로 진행되며 예건처리와 MA 포장이 배추의 생체중 감소를 지연시켰다. 가용성고형물 함량은 저장 후 4주까지는 예건처리구가 무처리구에 비해 많았으며, 저장 6주후에는 예건처리의 유무에 상관없이 무포장구가 MA포장구에 비해 높게 나타났다. 배추의 주요 가용성 당은 수확 직후 glucose 7.0mg/gFW와 fructose 6.3mg/gFW이며, sucrose가 0.6mg/gFW로 약간 함유되어 있다. 예건 직후 각각의 당은 감소하며, 저장 2주후 glucose와 fructose 함량은 크게 감소한 후 점차 증가하였다. 배추의 Hunter a, 경도, 건물중 함량, pH, 그리고 가용성 당의 변화는 예건조건 및 포장조건에 따른 변화를 분석하는데 적합하지 않았다. 실온저장의 배추는 2주후 심한 부패현상으로, 저온저장 7주후에 무포장구는 탈수현상으로 상품성을 상실하였다. 예건하지 않은 MA 저장 배추는 포장 내의 과습으로 인해 부패를 일으킨 반면 예건처리한 배추는 저온저장 7주까지도 외관상 초기 시료와 유사하였다. MA저장은 무포장에 비해 저장수명을 연장시키며, 수확 후 관행예건은 저장력을 향상시켰다.

• 한국환경보건학회지
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• 제35권1호
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• pp.21-35
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• 2009

The Asian dust storms which originated in the deserts of Mongolia and China transported particles to Korea and led to a high concentration of atmospheric particulate matters (PM) of more than $1000{\mu}g/m^3$ throughout the country in the spring, of 2007. Public concern, in Korea, about the possible adverse effects of these dust events has increased, as these dust storms can contain various air pollutants emitted from heavily industrialized eastern China. The objectives of this study were to understand the concentration characteristics of PM as a function of particle size between the Asian dust storm episodes and non-Asian dust period and to consider the mass size distribution of PM in the Asian dust storms and their water soluble ion species on the potential, possible effects on deposition levels in the three regions (nasopharyngeal, tracheobronchial, and alveolar) of the human respiratory system. The size distribution of PM mass concentration during the Asian dust storms showed a peak in the coarse particle region due to the long-range transport of soil particles from the deserts of Mongolia and China, which was identified by HYSPLIT-4 model for backward trajectory analysis of air arriving in the sampling site of Iksan. During the non-Asian dust period, there were two different types in PM size distribution: bimodal distribution when low concentrations of $PM_{2.5}$ were observed, while unimodal distribution having a peak in fine particle region when high concentrations of $PM_{2.5}$ were showed. This unimodal distribution with high concentrations of fine particulate and secondary air pollutants such as ${SO_4}^{2-}$, ${NO_3}^-$, ${NH_4}^+$ was found to be due to the long-range transport of air pollutants from industrialized eastern China. During the Asian dust storms, the mean concentrations of PM that can be deposited in the nasopharyngeal, tracheobronchial, and alveolar region were $128.8{\mu}g/m^3$, $216.5{\mu}g/m^3$, and $89.6{\mu}g/m^3$, respectively. During the non-Asian dust period, the mean concentrations of PM that can be deposited in the nasopharyngeal, tracheobronchial, and alveolar region were $8.4{\mu}g/m^3$, $9.5{\mu}g/m^3$ and $38.5{\mu}g/m^3$, respectively.

• 한국자원식물학회지
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• 제34권4호
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• pp.263-269
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• 2021

블루베리 재배 토양 개선에 적합한 유기자재를 선정하고자 대표적인 하이부쉬블루베리 품종인 'Duke'를 대상으로 피트모스, 이탄토, 소나무 발효톱밥 등 유기자재를 활용한 토양에서 블루베리의 생육 및 과실 특성을 조사하였다. 토양 산도는 4.2 ~ 4.8로 톱밥 > 이탄토 = 피트모스 수준이었다. 토양 중 유기물 함량은 톱밥의 경우 2.5%, 피트모스와 이탄토를 섞은 토양의 경우는 4.1%로 나타났다. 토양 경도는 토양 깊이 40 cm 위치까지 측정한 결과 1 ~ 5 kgf cm^-2으로 작물이 자라기에 적합한 것으로 나타났다. 흡지 수와 주축지 수는 이탄토 > 피트모스 > 톱밥 유기자재 처리구 순으로 많았다. 또한 피트모스와 이탄토 처리구의 흡지 굵기와 길이도 톱밥 처리구보다 긴 것으로 조사되었으며, 총 신초 수도 마찬가지의 양상으로 나타났다. 과실의 특성 중 과실의 중량, 과경, 횡경, 경도는 유기자재 처리 간에 통계적 차이가 나타나지 않았다. 가용성고형물 함량은 이탄토 > 피트모스 > 톱밥 유기자재 처리구 순으로 높게 나타났다. 과실의 수확량은 톱밥 처리구가 가장 낮은 것으로 나타났으며 피트모스와 이탄토 처리구는 비슷한 양상으로 나타났다. 따라서 토양 환경에 따른 수체 및 과실 특성을 종합하여 검토한 결과 국내 블루베리 재배 시 안정적인 생산을 위해서 피트모스를 이탄토로 대체하여 사용할 수 있을 것이라 판단되었다.

• 한국대기환경학회지
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• 제21권4호
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• pp.439-458
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• 2005

An automated analysis system for water soluble constituents in $PM_{2.5}$ has been developed. The system consists of a high capacity multi tube diffusion scrubber (MTDS), a low temperature particle impactor (LTPI), and two ion (anion and cation) chromatography (IC) systems. Atmospheric particles have been collected by passing sample air through a thermostated MTDS followed by a LTPI. This system allows simultaneous measurements of soluble ions in $PM_{2.5}$ at 30 minutes interval. At the air sampling flow rate of 1.0L/min, the detection limits of the overall system are in the order of tens of $ng/m^3$. This system has been successfully used for the measurement of particulate components of Seoul air from April 2003 to January 2004. $SO_4^{2-},\;NO_3^-,\;NH_4^+,\;NO_2^-,\;Cl^-,\;Na^+,\;K^+,\;Ca^{2+},\;and\;Mg^{2+}$ are the major ionic species for $PM_{2.5}$ at Seoul. Among them, $SO_4^{2-},\;NO_3^-\;and\;NH_4^+$ are the most abundant ions, contributed up to $86\%$ of the total and the concentrations were higher than those in any other urban sites in the world except for Chinese cities. There are high pollutant episodes which contribute about $15\~20\%$ of annual average values of the major ions. During the episode, the all parcels were transported from the asian continent and $PM_{2.5}$ were significantly neutralized. This suggests that aged and long range transported pollutants caused the high pollutant episodes. They showed a distinct daily and seasonal variations:they showed a peak in the early morning caused by the night-time accumulation of particulate matters. Atmospheric reactions including gas-to-particle reactions and inter-particle reactions and meteorological parameters including relative humidity and ambient temperature were described with related to the $PM_{2.5}$ 5 concentrations. All of the ionic species showed higher concentrations during the spring than those for summer and winter.