• Korean Journal of Microbiology
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• v.36 no.1
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• pp.52-57
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• 2000

A method for quantitative and qualitative analysis of geosmin, odorant produced by several actinomycetes and cyanobacteria, was established and optimized. The effects of environmental conditions on the growth of Phormidium sp. NIVA-CYA7 were examined and the production and release of geosmin by the species was analyzed by using the purge and trap-gas chromatographic technique. One of the major advantages of the technique established in the present study is that the preparation of sample is simpler and purge time is shorter. Under the culture conditions (pH 7.9, $20^{\circ}C$, 120-140 $\mu$E/$m^2$/s and Z8 medium), Phormidium showed growth characteristics with a lag phase for 8 days and an exponential phase for 14 days followed by a stationary phase. Reduction of inorganic nitrogen concentrations in the culture medium from 250 to 100 or 25 $\mu$M brought no significant effect on the cell growth. However, the cell growth was significantly inhibited with decreasing concentrations of inorganic phosphorus from 25 to 10 or 2.5 $\mu$M. When the inorganic phosphorus concentration in the medium was lowered from 25 to 10 $\mu$M, the levels of geosmin in the organism expressed as percentages per unit TOC and chlorophyII-$\alpha$ increased by 35% and 68%, respectively. When the initial pH of the medium was 9.4, geosmin content was 0.0824 $\mu$g/mg C, which was 2-fold higher than that at pH 7.9 Consequently, the level of geosmin in Phormidium was found to vary with growth phases of the culture, external inorganic phosphorus concentration and external pH, while the release of geosmin was not significantly affected by the factors.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.25-30
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• 1997

Volatile components of green tea were isolated by purge and trap headspace method and were analyzed by GC and GC/MSD. And ten headspace volatiles were compared with volatiles isolated by simultaneous distillation-extraction(SDE) method. A total of 99 components were identified in the green tea volatile components, from which 88 components were identified in the headspace volatiles, contained 20 alcohols, 30 hydrocarbons, 21 aldehydes, 10 ketones, 2 acids and 5 miscellaneous components. The major components were low boiling components, such as methyl butanal(3.1%), 1-penten-3-ol(5.48%), 2-penten-1-ol(2.89%), hexanal(5.77%), heptanal(1.90%), and ere 2,4-eptadienal(4.28%), linalool(2.27%), 2,6-dimethyl cyclohexanol(2.57%), $\alpha$-pinene(1.52%), caryophyllene(1.70%), and carbonyl compounds, such as $\alpha$-ionone(2.62%), $\beta$-ionone(2.98%), $\beta$-cyclocitral(2.0%). On the other hand SDE volatiles, from which 64 components were identified, contained 16 alcohols, 16 ydrocarbons, 15 aldehydes, 10 ketones, 3 acids and 4 miscellaneous components. The major components were alcohols, such as, benzyl alcohol(3.79%), linalool(9.52%), terpineol(2.16%), geraniol(2.75%), nerolidol(6.50%), ketones, such as $\alpha$-ionone(1.77%), $\beta$-ionone(4.80%), geranyl acetone(1.82%) and acids, such as hexanoic acid(1.45%), nonanoic acid(1.11%).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.831-832
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• 2012

• 한국데이터정보과학회:학술대회논문집
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• 2006.04a
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• pp.195-197
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• 2006

• 한국가스학회:학술대회논문집
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• 1999.09a
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• pp.179-184
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• 1999

• Journal of the KSME
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• v.32 no.10
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• pp.876-882
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• 1992

여기에서는 삼원촉매 장착엔진을 정밀하게 제어(연료 제어, 공회전 제어, 점화시기 제어, Purge Air 제어 등)하여 삼원촉매의 효율을 향상시키고, 그 결과 배기가스를 감소시킴과 더불어 운전성 및 동력성능을 향상시킨 엔진 전자 제어 시스템의 개요를 간단히 소개하였다. 앞으로도 북미지 역의 배기가스 관련법규가 더욱 강화될 것으로 예상되며, 이에 대응한 엔진 제어 시스템에 대한 지속적인 연구 개발이 필요하리라 생각된다.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.32-36
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• 2007

When the vacuum system for the process of $SiH_{4}$ gas used in the semiconductor and FPD field is partially vented from vacuum to atmospheric state, a fire often occurs due to auto-ignition of $SiH_{4}$ gas. In order to prevent the fire, the concentration of $SiH_{4}$ should be kept under LFL. This means that the higher capacity pump is needed to meet the process conditions as well as the condition that the concentration of $SiH_{4}$ should be kept under LFL. In this article, we conducted the injection of the dilution gas at the manifold between booster pump and dry pump compared with the typical method that the dilution gas was injected into inlet port of booster pump using computer simulation. According to the result, we can flow further more purge gas for safety without any change of the condition in the process chamber, which means that the higher capacity pump is not required for safety in some cases.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.140-140
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• 2001

A sensitive analytical method based on gas chromatograpy-mass spectrometry with a selected ion monitoring (GC/MS-SIM) with the purge-and-trap concentration and with headspace method (in limited applications) was developed for determining of epichlorohydrin in canned beverages coated with epoxy resin. The calibration curve in the range of $0.5\sim50ng$ had correlation coefficient greater than 0.998 and a detection limit of $0.l\mug/L$ was obtained using a sample volume of 20ml. The predominant ions of epichlorohydrin produced in MSD using electron ionization(EI) were m/z 57 ([M-CI]+) and 62/64 $([M-CH_2O]+)$. In survey of epichlorohydrin in thirty commercial canned beverage samples, none of them was detected.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.74-77
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• 2009

Ignition performance tests were performed to develop a catalytic ignitor which used hydrogen peroxide and kerosene. Ignition characteristics were investigated by exit area of the catalytic bed, shape of kerosene injector and lead time of purge gas. The results showed that exit area of catalytic bed must be enough for non chocking condition and kerosene must be sprayed with swirl in the middle of catalytic bed. Also in case without preheating of catalytic bed, hydrogen peroxide must be leaded by 3sec, and purge gas must be supplied simultaneously or lately with kerosene.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.549-563
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• 2005

The study was carried out to develop and standardize the analytical method of 1,4-dioxane in water. The National Institute of Environmental Research in Korea has monitored for 1,4-dioxane in water since 1998 and it has been detected in environmental water occasionally. But the environmental pollution and analytical method in water is not well known over the world. The trace analytical method at low-${\mu}/L$ level is prerequisite in order to evaluate the residue of 1,4-dioxane in water. Evaluation of the method was demonstrated by comparing and analyzing with liquid-liquid extraction, solid-phase extraction and purge & trap technique. As a result of experiment by standard solutions and raw samples, the precision and accuracy for three methods were obtained within error rate of about 10%. Therefore, three methods were standardized as official monitoring method in Korea. Also, a convenient and simple liquid-liquid extraction method for the analysis of 1,4-dioxane in water was developed by combined with gas chromatography/mass spectrometry and applied to the water samples in Korea