• Journal of Korea Soil Environment Society
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• v.3 no.3
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• pp.75-86
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• 1998

This paper is going to show the way we can sample the landfill gases flowing out to the air through final cover soil by using an closed chamber in the field for a short time. In addition, we came to the following results through the application of model with actual measurements. 1) Analyzing changes of concentration in the chamber(H: 10-30cm) every 5 minutes, considering analysis time of gas chromatograph for an half hour. 2) The proportion of $CE_4$to $CO_2$changes rapidly near the surface of final cover soil by the influence of methane oxidation reaction. 3) When flux of landfill gas is F=$10^{-5}$mol/$\textrm{m}^2$.s), methane oxidation reaction has an influence on composition of gases, however there is little influence when F=$10^{-6}$ mol/($\textrm{m}^2$.s).

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.30-34
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• 1999

Photolysis behavoirs of pesticides(Chlorothalonil and Endosulfan) over UV irradiation UV irradiation with pH 3.0 and irradiation with 3.5% salt were studied. The analyses of pesticides were carried out using gas chromatograph with an electron-capture detector, total organic carbon, and Ion chromatograph, respectively. The reactions were conducted in a alumium annular reactor equipped with a low pressure mercury multilamp ($8W{\times}6$) and initial concentration was 10 ppm. Chlorothalonil was almost photodegraded by UV irradiation, UV irradiation with pH 3.0 and 3.5% salt within 30 min of reaction time. Endosulfan-${\alpha}$,${\beta}$(100%) were photodegraded to 38% of Endosulfan-${\alpha}$ and 25% of Endisulfan-${\beta}$ by UV irradiation. Endosulfan-${\alpha}$(83%) was photodegraded to 66% by UV irradiation, 70% by UV irradiation and pH 3.0 and 75% by UV irradiation and 3.5% salt. Endosulfan-${\beta}$(16%) was photodegraded to 80% by UV irradiation, 98% by UV irradiation and pH 3.0 and 90% by UV irradiation and 3.5% salt.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.634-640
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• 2016

The objective of this study was to evaluate the effectiveness of using HR-GC/MS for the rapid screening of dieldrin residues in soils. Persistent organic pollutants (POPs) of organochlorine pesticides such as dieldrin, were analyzed in sedimentary rock and granite rock collected from greenhouses, Niigata, Japan. Dieldrin remains in Japanese farming soils, more than 40 years after their use as insecticides was prohibited. The averages in soil moisture ranged from 2.79% to 7.20% in soils derived from sedimentary rock and from 25.59% to 31.40% in soils derived from granite rock. Mean concentrations of dieldrin residues in sedimentary rock and granite rock were $39.7ng\;g^{-1}$ and $40.51ng\;g^{-1}$, respectively. Dieldrin residue was detected at a slightly higher concentration in granite rock than sedimentary rock samples. There was no consistency between the two soils or between surface and subsurface soils. The coefficients of variation of the two soils were 10.6% and 8.7%, respectively. These results suggest that our high-resolution mass spectrometry detector (HR-GC/MS) is effective at analyzing residual organochlorine pesticides in soil. In order to increase the precision and sensitivity for chemical analysis of POPs, high-resolution gas chromatography coupled with a HR-GC/MS is highly recommended.

• Analytical Science and Technology
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• v.12 no.2
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• pp.136-140
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• 1999

Lupenone and lupeol, the triterpenoids of Sorbus Cortex, were isolated with silica gel column chromatography and used as the standard substances for the quantitative analysis. The compounds were identified with IR, NMR, EI-MS. They were separated on VA-5MS [(5%-phenyl)methylpolysiloxane, $30m{\times}0.25mm$, $0.25{\mu}m$] column by gas-chromatograph. The contents of lupeone and lupeol in three different samples of Sorbus Cortex were in the range of 0.050~0.056% and 0.772~0.834%, respectively.

• Korean Journal of Food Science and Technology
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• v.5 no.1
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• pp.65-69
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• 1973

Effect of various dosages of gamma ray ranging from 0 to 16 krad on wound periderm formation was investigated with aging potato tuber slices $(1cm{\times}2mm)$ under aseptic condition. Cell division was gradually inhibited with increasing dosage, and completely prevented with 16 krad treatment. Solanine content was not significantly different due to dosages. Gas chromatographic separation of 2,4-dinitrophenylhydrazone precipitate from radiation-induced carbonyl compounds in potato tubers showed that formaldehyde and acetone tended to be increased only with high dosages.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.295-300
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• 1997

Flavor components of natively grown tea plant(Camellia sinensis O. kuntze) in Korea, collected from 12 locations, were analyzed by gas chromatograph and mass spectrometer. Seventy to eighty flavor components in tea leaves were separated by GC. Total 52 flavor components were identified by comparing gas chromatograhp retention time and mass spectral date. They were classified as 19 alcohols, 5 aldehydes, 2 hydrocarbons, 6 ketones, 4 esters, 3 lactones, 2 acids, 3 phenols, 4 pyrazines, and 4 nitrogenous compounds. Major compounds identified were geraniol, linalool oxide, 1-hexanol and ethanol.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.513-518
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• 2005

The co-pyrolysis characteristics of poly(vinyl chloride) (PVC) and polystyrene (PS) mixtures with ZnO have been studied by thermogravimetry (TG) and gas chromatograph-mass spectrometry (GC-MS) under various mixing ratios and reaction temperatures. From this work, it was found that the yield of liquid products increased as PS in mixtures increased, whereas that of gaseous products decreased. And as ZnO in mixtures increased, the yields of gaseous products and HCI decreased. The optimal reaction temperature for the maximum yield of liquids products and the control of HCI gas was $500^{\circ}C$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.6
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• pp.269-274
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• 2014

The experimental performance evaluation of a cylindrical steam reformer with various thermal conditions has been conducted. The bottom space of the cylindrical reactor was packed with Ruthenium (Ru) catalyst. A three-segment furnace was installed to create the axially variable boundary temperature distribution. Six K-type thermocouples were inserted into the catalyst layer, and three exhaust ports were fabricated on the side wall along the flow direction. The exhausted gases at each port were analyzed by using gas chromatograph (GC) system. The experimental results showed that the reforming reaction occurs intensively in the upstream region and more hydrogen is obtained when the intake gas is sufficiently heated up through the enhanced steam reforming (SR) reaction. The axially increasing boundary temperature setup provided the maximally accumulated reforming efficiency of 74.8%, when the reactor was placed at the 3rd section of the furnace.

• KSBB Journal
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• v.5 no.1
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• pp.25-35
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• 1990

In the Xanthan gum fermentation by Xanthomonas campestris there are problems of the large energy consumption by long fermentation time, the mass transfer of oxygen and nutrients by high viscous fermentation broth. In this study, the media optimization and the fed batch fermentation were carried out to decrease fermentation time and increase Xanthan gum yield. The $O_2$ uptake rate (OUR) and $CO_2$ evolution rate(CER) which were obtained from the analysis of fermentation exit gas using a gas chromatograph were investigated. As a result, the fermentation time decreased at optimal assimilable nitrogen concentration but increased at poor or rich assimilable nitrogen concentration, the Xanthan gum biosynthesis was stimulated under the limited condition of assimilable nitrogen source and the optimum fermentation medium was obtained as follow; Glucose=30g / l, Peptone=8.0g / l, $K_2HPO_4=2.0g/l$, $MgS0_47H_2O=10g/l$, Sodium acetate=20g/l, Sodium pyruvate=0.5g/1. As the agitation speed and nitrogen concentration increased, the $O_2$ uptake rate and $CO_2$ evolution rate increased. The OUR and CER were 37.3mmol $O_2/\;l$ hr and 20.2 mmol $CO_2/\;L$ hr at peptone 11g / l and agitation speed 990RPM, respectively. In fed batch fermentation, the final concentration of Xanthan gum was enhanced up to 29g / l.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.890-893
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• 2012

Gas hydrates are solid crystal structures formed by enclathration of gaseous guest species into 3-dimensional lattice structure of hydrogen-bonded water molecules. These compounds can be potentially used as an energy storage/transportation medium because they can hold a large amount of gas in a small volume of the solid phase. In addition, huge amount of natural gas, buried in seabeds or permafrost region in the form of the solid hydrate, is regarded as a future energy source. In this study, synthesized natural gas, whose composition is 90.0 mol% of methane, 7.0 mol% of ethane, and 3.0 mol% of propane, was used to identify formation behaviors of natural gas hydrates for the purpose of applying the gas hydrate to a storage/transportation medium of natural gas. According to the experimental results obtained by means of the solid-state NMR and high-resolution powder XRD methods, it is found that formed natural gas hydrates have crystal structure of the structure-II hydrate, and that methane occupies both small and large cages, while the others only occupy large ones. In addition, both the NMR spectroscopy and the gas chromatograph showed that there exists preferential occupation among the natural gas components during the hydrate formation. Compositional changes after the hydrate formation revealed that the preferential occupation is in order of propane, ethane, and methane (propane is the most preferential guest species when forming natural gas hydrates).