• Biotechnology and Bioprocess Engineering:BBE
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• 제7권2호
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• pp.105-111
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• 2002

The biological removal of 2,4,6-trinitrotoluene (TNT) was studied in a bench-scale bioreactor using a bacterial culture of strain OK-5 originally Isolated from soil samples contaminated with TNT. The TNT was completely removed within 4 days of incubation in a 2.5 L bench-scale bioreactor containing a newly developed medium. The TNT was catabolized in the presence of different supplemented carbons. Only minimal growth was observed in the killed controls and cultures that only received TNT during the incubation period. This catabolism was affected by the concentration ratio of the substrate to the biomass. The addition of various nitrogen sources produced a delayed effect for the TNT degradation. Tween 80 enhanced the degradation of TNT under these conditions. Two metabolic intermediates were detected and identified as 2-amino-4, 6-dinitrotoluene and 4-amino-2, 6-dinitrotoluene based on HPLC and GC-MS analyses, respectively. Strain OK-5 was characterized using the BIOLOG system and fatty acid profile produced by a microbial identification system equipped with a Hewlett Packard HP 5890 II gas chromatograph. As such, the bacterium was identified as a Stenotrophomonas species and designated as Stenotrophomonas sp. OK-5.

• 청정기술
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• 제4권1호
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• pp.35-44
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• 1998

휘발성 유기화합물(벤젠, 톨루엔, 에틸벤젠, 크실렌)의 광분해를 단순 UV조사와 $TiO_2$ 광촉매하의 UV조사를 이용하여 연구하였고 또한 여러 가지 반응조건에 따른 분해효율에 대해 고찰하였다. 광분해반응기는 중압 수은램프가 부착된 석영 annular 반응기를 이용하였다. UV조사에 의한 휘발성유기화합물의 분해정도는 톨루엔 92% ${\geq}$ 에틸벤젠 92% > 벤젠 83% > 크실렌 82% 였고, $TiO_2$ 광촉매하의 UV조사를 이용한 유기물의 분해정도는 톨루엔 92% > 크실렌 82% > 에틸벤젠 80% > 벤젠 53% 였다. 반응물의 분석은 Purge & Trap 농축기를 이용하여 FID가 부착된 GC로 분석하였고, GC-MS로 반응물의 중간생성물을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.345-349
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• 2003

The quantity, process and kinetics of di-(2-ethylhexyl)phthalate (DEHP) migration in the 30/70 and 40/60 poly(vinylchloride) (PVC)/DEHP blends were investigated using gas chromatograph. A thin and flexible PVC sheet was soaked in surrounding medium (SM) of water/ethanol mixture and acetonitrile with constant stirring to release DEHP. By observed concentration of DEHP in the SM, it is found that acetonitrile is more intense in DEHP migration than water/ethanol mixture. In addition the amount of extracted DEHP is proportional to the leaching temperature and added ratio of DEHP. The behavior of DEHP migration from flexible PVC sheets was described by the Ficks's law with $2.72-10.1\;{times}\;10^{-10}$ cm²/s of the diffusion coefficients.

• 대한기계학회논문집B
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• 제29권3호
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• pp.376-383
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• 2005

In the paper we investigate characteristics of a transitional behavior from a premixed flame to a triple flame in a lifted flame according to the change of equivalence ratio. In previous study, we showed that the stabilized laminar lifted flame regime is categorized by regimes of premixed flame, triple flame and critical flame. A gas-chromatograph is used to measure concentration field, a smoke-wire system is used to measure streak line, and a PIV system is used to measure velocity field in lifted flame. In the visualization experiment of smoke wire, the flow divergence and redirection reappeared in premixed flame as well as triple flame. Thus we cannot express the flame front of lifted flame has a behavior of triple flame with only flow divergence and redirection. In PIV measurement, flow velocity for those three flames has minimum value at the tip of flame front. To differentiate triple flame and premixed flame, $\Phi$ value of partially premixed fraction is employed. The partially premixed fraction $\Phi$ was constant in premixed flame. In critical flame small gradient appears over the whole regime. In triple flame, typical diffusion flame shape is obtained as parabolic distribution type due to diffusion flame trailing.

• Applied Biological Chemistry
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• 제21권3호
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• pp.185-192
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• 1978

제초제((除草劑)중 국내에서 많이 사용되는 nitrofen(NIP, TOK), butachlor (Machete) 및 alachlo (Lasso의 잔류성(殘留性)을 조사하기 위하여 가수분해를 거치지 않고 전자(電子)포획검출기가 부설된 깨스크로마토그래피로 분석하는 방법을 확립시킨 후 이들 제초제를 유지(油脂)작물인 유채(油菜), 대두(大豆) 및 수도(水稻)의 재배포장에 사용(施用)하였을 때의 잔류량(殘留量)을 분석하였다. 그 결과 세가지 제초제(除草劑)는 사용후 2주일만에 급격히 감소하였으며 그 이후에는 점차적으로 감소하여 10%수준에 도달하였다. 그러나 유지(油脂)원료인 세 작물의 종자(種子)에는 분석한계치(分析限界値)안에서 전혀 검출(檢出)되지 아니하였다.

• 한국농공학회지
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• 제36권1호
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• pp.141-152
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• 1994

Our experiment investigated the degree of soil contaimination caused by oil leakage. Each soil sample was taken by boring 5, 8m below the test areas, located 5 to 30m from storage tanks at oil stations. According to the results from a series of laboratory tests(both soxhiet extract test and gas chromatograph test), Traces of a light oil were found in all samples except in Dj8, rocky soil and gasoline and petroleum were not detected. We concluded that soil contamination was caused by the corrosion of storage tanks or alternatively by oil overflow caused during the flooding of underground water seeping into the tank during heavy rain fall or the spillage caused by carelessness during lubrication. Old stations without a concrete box enclosing their metal tanks run a greater risk of oil leakage. To research the effect of oil leakage on plant growth and underground water, We examined the results of research conducted overseas. According to these results, when oil leakage occurs, plant growth is repressed and agricultural crops experience low productivity levels. Also, the contamination of underground water can be serious when oil spreads to the aquifer layer. As a result of these problems, to prevent oil leakage and minimize its contaminating effects at oil stations, it is necessary to improve facilities of storage tanks and have the monitoring system of oil leakage.

• Environmental Analysis Health and Toxicology
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• 제18권3호
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• pp.219-224
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• 2003

1,4-Dioxane is used as a solvent for lacquers, paints, varnish removers, dye baths and printing compositions. And it is also used for detergent preparations, cosmetics, deodorants and fumigants. A method is described for the determination of 1,4-dioxane in water samples by GC/MS. The extraction recoveries were studied for some solvents and solvent volume ratio were investigated using r-butyl methyl ether (MTBE). Optimum condition was obtained by the liquid-liquid extraction using the 10 mL of MTBE for 10 mL of water. Method detection limit of 1,4-dioxane in the 20 mL of water samples was 0.05 ng/mL. It could be determined in the range of 0.24∼240 ng/mL in treated water, and in the range of 0.69∼81.9 ng/mL in raw water, respectively. Risk assessments with 1,4-dioxane exposure by drinking water ingestion were carried out. Based on the results of analysis, chronic daily intake of 1,4-dioxane was 2.22${\times}$10$\^$-4/ mg/kg/day and excess cancer risk was calcu-lated to be 2.44${\times}$10$\^$-6/.

• 한국환경과학회지
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• 제23권10호
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• pp.1763-1773
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• 2014

It is known that mackerel and pork belly release a strong odor in the process of roasting. We evaluated a dilution factor of odor arising during roasting mackerel or pork belly and the relative odor strength using several cooking tools and analyzed compounds causing odors with gas chromatograph/mass detector. Roasting pans used were grill with lid, electric grill without lid and general roasting pan, and a grill with lid can attach the activated carbon charcoal deodorant at the inside of lid. And all electric grills have a drip tray under the heater. We investigated characteristics of odor emission depending on the presence of water and deodorants in these cooking tools. Study has shown that roasting mackerel produces approximately 36 time more odors than roasting pork belly, and the reduced odor emission when roast with water. And it shows the reduced deodorant effect when cooked with water after attaching activated carbon charcoal in the cooking pan. Major odor causing compounds arising when cooking mackerel and pork belly were aldehydes with high boiling point such as octyl aldehyde with a low odor threshold value.

• Applied Biological Chemistry
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• 제35권5호
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• pp.346-350
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• 1992

한국 재래식 간장의 많은 휘발성 향기성분 중에서 특징적인 향기성분을 규명하고자 하였다. 연속 수증기 증류 추출장치로 휘발성 향기성분을 추출하고 재래식 간장향을 나타내는 중성획분을 분획하여 농축하였다. 이를 GC-관능검사에 의해 각 peak성분의 방향성을 조사하고, 이 각 peak성분을 fraction collector APP-5가 부착된 preparative GC로 분획포집한 후, 이를 GC/MS로 분석 동정하였다. 그 결과 GC-관능검사에서 불쾌취를 나타내는 향기성분으로는 3-methyl-1-butanol을, 간장향을 나타내는 향기성분으로는 dimethyl trisulfide, benzeneacetaldehyde, benzeneethanol을 각각 동정하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.152-152
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• 2013

Mechanism of energy conversion from chemical to electrical during exothermic catalytic reactions at the metal surfaces has been a fascinating and crucial subject in heterogeneous catalysis. A metal-semiconductor Schottky nanodiode is novel device for direct detection of chemically induced hot electrons which have sufficient energy to surmount the Schottky barrier. We measured a continuous chemicurrent during the hydrogen oxidation under of 760 Torr of O2 and 6 Torr of H2 by using Pt/Si and Pt/TiO2 nanodiodes at reaction temperatures and compared the chemicurrent with the reaction turnover rate. The thermoelectric current was measured by carrying out an experiment under O2 condition for elimination of the background current. Gas chromatograph and source meter were used for measurement of the chemical turnover rate and the chemicurrent, respectively. The correlation between the chemicurrent and the chemical turnover rate under hydrogen oxidation implies how hot electrons generated on the metal surface affect hydrogen oxidation.