• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.389-397
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• 1999

Recently the use of Pd catalyst have been continued to expand because of cost avaliabilityand performance advantages. Especially the Pd+Rh catalyst instead of the Pt+Rh catalyst had been used for most of three way catalysts because of the more stringent emission standards and its higher temperature effectiveness. The main purpose of this study is to investigate the design parameter impacts on the Pd+Rh cat-alyst for the automotive exhaust catalysts application. This study was investigated on the catalyst efficiency for the volume and the precious metal loading of the Pd+Rh ceramic monolithic cata-lyst. And experiments concerning the effects of volume and precious metal loading on Pd+Rh three way catalysts were conducted to examined the catalyst light-off temperature and conver-sion efficiency on higher volume demonstrated almost similar performance. But their effects on higher precious metal loading demonstrated considerably better performance.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.155-158
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• 2005

본 연구에서는 현장규모의 biopile을 제작하여 유류로 오염된 토양을 정화하였다. 오염토양의 TPH농도는 평균 2,800mg/kg(최고 3,590mg/kg)이었으며, 오염토양의 양은 $746m^3$이었다. Biopile $(17{\times}20{\times}2.5m)$을 약 3개월간 운전하며 일정 시간 간격으로 토양가스($O_2,\;CO_2)$ 및 VOCs) 및 토양의 TPH농도를 분석하였다. 지속적인 공기의 주입/추출에 의해 biopile내부는 호기조건을 유지하였으며, 미생물의 활성도 증가에 따라 이산화탄소의 농도가 증가하는 경향을 나타내었다. 또한 토양가스 분석결과 휘발성 유기오염물질(VOCs)은 약 40일 경과 후 90% 제거되었으며, 90일 경과 후 토양의 TPH 제거율은 98%로 나타났다.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.92-100
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• 2000

The model gas reaction tests were carried out to investigate the purification characteristics of methane on the exclusive catalyst for NGV. The experiment was conducted with the factors which affect the conversion efficiency of methane, such as Redox ratio, coexistence components of CO, MO, $H_2$O, precious metals and additives. The catalyst loaded with larger amount of pd and with additive La showed lower light-off temperature. In the presence of CO and NO, the conversion efficiency of methane was varied according to the kind of additive loaded. The conversion efficiency of methane was dropped for the catalyst loaded with La under lean air-fuel ratio, while it increased for the one loaded with Ti+Zr for the same condition. It was shown that the water vapor inhibited methane from oxidation by its poisoning on the surface of catalyst.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.15-26
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• 1997

In this study, the theoretical investigation of the electrically heated catalyst(EHC) for vehicle application has been carried out using the thermal equivalence of EHC system and the data of vehicle tests to meet ultra low emission vehicle(ULEV) standard. To improve the efficiency of EHC system, it is necessary to understand relation between the power, the operating time and the conversion efficiency of EHC system. The relation was found with thermal equivalence of EHC system which considers the power supply to EHC, heat loss, chemical exothermic energy generated by oxidation reaction and net energy coming in via the exhaust gas. From this relation, the limits of needful power and operating time to meet the ULEV standard can be suggested, when the conversion efficiency of catalyst was known.

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.276-279
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• 2006

내부 순환형 회분식 반응기에서 UV/$TiO_2$ 시스템을 이용하여 기상의 아세톤과 알데히드류 유기화합물 분해 반응 특성을 온도와 농도 및 자외선 파장 및 광도에 대하여 고찰하였다. 또한 기존의 공기정화기에 장착할 수 있는 담체를 도출하고자 하였다. 새로운 광촉매 담지체로는 전처리 필터로 사용되는 메쉬망 형태를 사용하였으며, 광조사율이 높고 광촉매의담지량을 늘릴 수잇는 방안에 대한 연구를 수행하였다. 본 연구 결과 광접촉 면적 대비 높은 반으성을 나타내었으며 Pt, Pd 등의 첨가에 의한 반응성 상승이 나타났다. 메쉬망 형태의담지체 사용시 광조사면적 대비 담지량의증가에 의하여 온도에 의한 흡착특성에 따른 영향을 더 크게 받는 것으로 나타났다.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.122-129
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• 2002

The removal rate of heavy metals from the wastewater, the accumulation and translocation of heavy metals in plants after transplanting, and the responses of water celery growth with different wastewater treatments were investigated to determine the potential ability of green-remediation with hydroponic culture of water celery. The removal rate and translocation of Cd, Cu, Ni and Pb from different wastewater to plants were compared with cultivation periods after transplanting. The removal rate of heavy metals from wastewater was different with each treatment but increased with growing periods of water celery plants. The removal rate of Cd, Cu, Ni and Pb in Artificial solution, Artificial solution+EDTA, Munmark industrical wastewater, Jungsun minewater is ranged from 22 to 73%, from 28 to 100%, from 13 to 92% and from 41 to 100% at 6 days after transplanting, respectively. The translocations of Cd, Cu, Ni and Pb from roots to shoots in Artificial solution, Artificial solution+EDTA, Munmark industrical wastewater, Jungsun minewater are ranged from 14 to 28%. 8 to 30%. from 28 to 45% and from 2 to 15% at 12 days after transplanting, respectively. In plant growth responses, it appears to be inhibited the plant growth over all treatments excepts for Munmark industrial wastewater in these glowing periods. Therefore the water celery might play a useful role in phytoremediation to clean up wastewater contaminated with Cd, Cu, Ni or Pb.

• Korean Journal of Environment and Ecology
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• v.15 no.2
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• pp.118-124
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• 2001

본 연구의 목적은 도식에 식재된 두 침엽수조인 소나무와 잣나무 단목의 연간 $CO_2$, $SO_2$, $NO_2$ 흡수 및 $O_2$ 생산을 계량화하는 것이다. 자연환경 조건하에서 운반형 적외선가스분석기로 연간 $CO_2$교환율을 측정하여 $CO_2$흡수 및 $O_2$ 생산량을 그리고 $CO_2$와 SO$_2$EH는 $NO_2$간 흡수속도비를 적용하여 $SO_2$ 및 $NO_2$흡수량을 각각 산정하였다. 흉고직경을 독립변수로 단목의 생장에 다른 연간 $CO_2$흡수 및 대기 정화량을 추정하는 활용 용이한 방정식을 유도하였다. 연구대상 수목 중, 흉고직경 20cm인 잣나무는 연간 양 35kg의 $CO_2$, 11g의 $SO_2$, 19g의 $NO_2$를 각각 흡수하였고 25kg의 $O_2$를 생산하였다. 동일 직경의 소나무는 유도한 방정식을 적용하면, 연간 약 30kg의 $CO_2$, 9g의$ SO_2$, 15g의 $NO_2$를 각각 흡수하였고 22kg의 $O_2$를 생산하였다. 생상기간 중 단위엽면적당 $CO_2$흡수량은 잣나무가 소나무보다 적었으나, 단목의 연간 $CO_2$흡수 및 대기정화량은 총엽면적의 차이로 잣나무가 동일 직경의 소나무보다 많았다. 본 연구결과는 도시 침엽수의 연간 대기정화 가치를 용이하게 계량화학고 도시공간내 수목식재의 환경적 중요성을 홍보하는데 활용될 수 있다.

• Polymer(Korea)
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• v.27 no.6
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• pp.521-527
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• 2003

It was found that polypropylene shows rearrangement of crystal structure during the melting process. For the analysis of recrystallization behavior, the change of dynamic mechanical property, crystallinity, and crystal structure were studied by DSC, FT-IR, SAXS, and DMA. Melt-recrystallization-remelting behavior of iPP was clearly observed when iPP was cooled down kom the melt more rapidly. Elastic modulus of iPP increased during the recrystallization process but crystallinity of iPP shows constant value. Furthermore, the full width of half mean of SAXS pattern decreased about 30%, and intra-lamella ordering of iPP increased during the melt process but is was not found for sPP.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.83-84
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• 2014

This study evaluated the effectiveness of biostimulating agent in contaminated coastal sediment. The study was conducted via column tests in coastal sea wherein two separate columns were employed for two different polymers used and another column for a blank. The biostimulating agent was made by mixing sea sediment with biostimulants viz acetate, nitrate, sulfate. The biostimulating agent was then rolled into balls, dried and coated with either Cellulose Acetate (CA) or Polysulfone (PS) to control the release of the biostimulants. The pH was around 7.6~8 for 4 months while COD, TP and TN were significantly lower in the column containing biostimulating agents. Heavy metal(Fe, Zn, Cd, Cr, Pb, Cu) was converted to stable forms and PS coated biostimulating agent had a high efficiency of heavy metals distribution.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1C
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• pp.9-17
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• 2006

The numerical analysis to predicting the electrokinetic remediation behavior on unsaturated soil is carried out by aiding HERO, Hanyang Unversity Electrokinetic Remediation program, developed from the finite difference method and in the VISUAL FORTRAN environment. The analysis for the pure kaolinite under saturated conditions is performed on the results of the previous study of Acar (1997). Also the predictions to the characteristics of electrokinetic remediation on unsaturated conditions are performed and the conclusions summarized as follows. First, pH of the electrolyte in the reservoirs is not different with the degree of saturation resulted from the changes in electrical efficiency. But the advance of acid front is increased dependent on the degree of saturation in contrary to the transportation of base front. Second, below the degree of saturation of 83%, which is equivalent to the optimum water content, the removal effect increased with the decreasing of degree of saturation. But it have no effect on the efficiency of removal over the degree of saturation of 83%.