• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.114-122
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• 2000

This study was carried out to investigate the changes in the composition of essential oils for the improvement of air-curing process of burley tobacco leaves. From the essential oils isolated from the cured tobacco leaves by steam distillation method, 90 compounds including 15 acids and esters, 19 alcohols, 23 aldehydes and ketones, 19 hydrocarbons, and 14 miscellaneous compounds, could be identified by gas chromatography and gas chromatography-mass spectrometry. Among them, acids and esters were gradually decreased during the progress of curing after harvesting. A rapid increase in alcohol content was observed in the earlier stage of curing, but thereafter, decrease followed until the end of curing However, aldehyde and ketone groups were continuously increased during curing and were 3 times higher in quantity after curing than at the harvesting time. The concentration of hydrocarbons was increased in the earlier stage of curing, but gradually decreased from the middle stage. The miscellaneous compounds were continuously increased in content until the end stage of curing, with rapid increased in the earlier stage of curing.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.79-85
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• 2003

The purpose of this study was to disclose the manufacturing process of activated carbon using coal. It investigated the influences on the physical properties that were manufactured activated carbon by using anthracite coal, bituminous coal under carbonizated and activated condition. The adsorption capacities of organic material were superior when the ash content was lower 5∼10%, and the iodine value was about 1,000 mg/g, the adsorption capacity decreased rapidly when ash content was over 15%. The manufactured activated carbon were found characteristics such as the iodine value was over 1,031 mg/g, the specific surface area was over 1,032 $m^2$/g and the hardness was over 95% under manufacturing conditions which were carbonizated temperature of $600^{\circ}C$( 180 minute), activated temperature of 95$0^{\circ}C$(210 minute) and steam weight of 6 $m\ell$/min.100 g coal.

• Korean journal of food and cookery science
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• v.6 no.1
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• pp.1-8
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• 1990

To study the most optimum condition of Dongchimi, the various Dongchimi distinct from the amount of salt, the temperature of fermentation and the ratio of radish to water were examed by sensory evaluation. Also, the content of volatile organic acids and nonvolatile organic acids were investigated by GC, the content of sulfur compounds by GC/MS. Volatile organic acids were identified with those butyl esters and nonvolatile organic acids were done with those TMS derivatives. Sulfur compounds and those decomposed products were extracted by steam distillation In results, the most optimum conditions ware salt 2.4% fermented temperature $4^{\circ}C$, ratio 1:1.5. Volatile organic acids detected were formic, acetic acid, and the amounts were effected by saltness. Nonvolatile organic acids detected were lactio, malio, fumario, tartario acid. Lactic acid was thought to effect overall eating quality. Sulfur compounds were almost the isothiocyanate groups in raw radish, which little in fermented Dongchimi.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.4
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• pp.337-345
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• 2012

To check effects of operating variables on reaction characteristics of WGS catalyst for SEWGS process, water gas shift reaction tests were carried out in a pressurized fluidized bed reactor using commercial WGS catalyst and sand(as a substitute for $CO_2$ absorbent) as bed materials. Simulated syngas(mixed with $N_2$) was used as a reactant gas. Operating temperature was $210^{\circ}C$ and operating pressure was 20 bar. WGS catalyst content, steam/CO ratio, gas velocity, and syngas concentration were considered as experimental variables. CO conversion increased as the catalyst content and steam/CO ratio increased. CO conversion at fluidized bed condition was higher than that of fixed bed condition. However, CO conversion were maintained almost same value within the fluidized bed condition. CO conversion decreased as the syngas concentration increased. The optimum operation condition was confirmed and long time water gas shift reaction test up to 24 hours at the optimum operating conditions was carried out.

• Journal of the Korean Wood Science and Technology
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• v.17 no.3
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• pp.1-7
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• 1989

This study was performed to obtain the optimal condition that hydrolyzed exploded pine(Pinus densiflora), oak(Quercus serrata) and birch wood(Betula platyphylla var. japonica) by using sulfuric acid. The results obtained were summarized as follows: In hydrolysis of wood meal with sulfuric acid. maximum yield of sugar appeared that pine was 12 hours. oak and birch were 24 hours with 65% sulfuric acid. Futhermore, when wood meal and exploded woods were hydrolyzed with 65% sulfuric acid at $23^{\circ}C$ for 6 hours(primary hydrolysis), diluted to 3% and hydrolyzed again at $100^{\circ}C$ for 2 hours(secondary hydrolysis), the maximum sugar yield of wood meals were 6 hours. those of higher steam exploded pine wood was 3 hours. of lower steam exploded oak and birch woods were 6 hours. The sugar analyses of exploded wood showed that the amount of arabinose and xylose residue rapidly decreased. content of nemicelluose decreased with increase of steaming time and pressure.

• Journal of the Korean Chemical Society
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• v.15 no.2
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• pp.55-63
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• 1971

In this study, several nickel catalysts for the steam-hydrocarbon reforming process were prepared from various nickel salt, magnesium oxide, alumina and kaolinite. The activity and strength of the catalysts were investigated. 1. The proper composition of the calcined catalysts are: NiO (5-15%)-MgO(10-20%)-$Al_2O_3$(10-40%)-Kaolinite(50-80%). 2. The admixed or cosedimented ingredients of the catalysts was pelletized and calcinated at 1000 or $1150^{\circ}C$. Calcination at $1150^{\circ}C$ for an hour was optimum. 3. The water to oil ratio (W/O) for reforming of hexane should be above 7 mole/mole. As the W/O increases, more carbon dioxide and hydrogen, but less carbon monoxide was produced. Also carbon deposition become lessen at higher W/O. 4. Maximum conversion had attained at about $850^{\circ}C$. As the reaction temperature increases, more carbon monoxide and hydrogen, but less carbon dioxide and lower hydrocarbon was produced. 5. The percent conversion at $850^{\circ}C$ was about 80%, using a catalyst which the nickel oxide content are 5%.

• The Korean Journal of Food And Nutrition
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• v.29 no.2
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• pp.153-161
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• 2016

This study investigated the chemical composition of Solidago virga-aurea var. asiatica Nakai essential oils collected using different extraction methods. The essential oils obtained by simultaneous steam distillation extraction (SDE) and hydrodistillation extraction (HDE) methods from the aerial parts of Solidago virga-aurea var. asiatica Nakai were analyzed by GC and GC-MS. Ninety-nine volatile flavor compounds were identified in the essential oil produced from Solidago virga-aurea var. asiatica Nakai using the SDE method. These compounds were classified into eight categories in terms of chemical functionality: 26 hydrocarbons, 8 aldehydes, 36 alcohols, 7 ketones, 12 esters, 5 oxides and epixides, 4 acids, and a miscellaneous one. Spathulenol (15.66%) was the most abundant compound. Ninety-eight compounds including of 35 hydrocarbons, 6 aldehydes, 29 alcohols, 6 ketones, 10 esters, 4 oxides and epixides, 7 acids, and a miscellaneous one were identified in the essential oil from the plant using the HDE method. Hexadecanoic acid (24.74%) was the most abundant compound. The chemical composition of Solidago virga-aurea var. asiatica Nakai essential oils extracted by SDE and HDE methods are characterized by high content of sesquiterpene alcohols and acids, respectively. The extraction methods may be influenced in the chemical composition of natural plant essential oils.

• International Journal of Concrete Structures and Materials
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• v.11 no.2
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• pp.391-401
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• 2017

In this study, the effects of water-to-binder (W/B) ratio and replacement ratio of blast furnace slag (BFS) on the compressive strength of concrete were first investigated to determine an optimized mixture. Then, using the optimized high-strength concrete (HSC) mixture, hooked steel fibers with various aspect ratios and volume fractions were used as additives and the resulting mechanical properties under compression and flexure were evaluated. Test results indicated that replacement ratios of BFS from 50 to 60% were optimal in maximizing the compressive strength of steam-cured HSCs with various W/B ratios. The use of hooked steel fibers with the aspect ratio of 80 led to better mechanical performance under both compression and flexure than those with the aspect ratio of 65. By increasing the fiber aspect ratio from 65 to 80, the hooked steel fiber volume content could be reduced by 0.25% without any significant deterioration of energy absorption capacity. Lastly, complete material models of steel-fiber-reinforced HSCs were proposed for structural design from Lee's model and the RILEM TC 162-TDF recommendations.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.772-779
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• 2011

New type of syngas generator based on the partial oxidation of biogas in volumetric permeable matrix reformers was suggested as an effective, adaptable and relatively simple way of syngas and hydrogen production for various low-scale applications. The use of biogas as an energy source reduces the chance of possible emission of two greenhouse gases, $CH_4$ and $CO_2$, into the atmosphere at the same time. Its nature of being a reproducible energy source makes its use even more attractive. Parametric screening studies were achieved as air ratio, biogas component ratio, input gas temperature, Steam/Carbon ratio. As the air ratio was low, the production of the hydrogen and carbon monoxide increased in the condition that 3D matrix reformer maintains the stable driving. As it was the simulation biogas in which the carbon dioxide content is high, the flammable range became narrow. And the flammable range was extended if the injected gas was preheated. The stable driving was possible in the low air ratio. The amount of hydrogen production was increased as S/C ratio increased.

• Korean Journal of Food Science and Technology
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• v.22 no.4
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• pp.445-450
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• 1990

Changes in weight, volume and density of petiole tissue of Chinese cabbage during salting and blanching were investigated. Rapid changes in mass and volume occurred within 4 hours during salting in 5% salt solution and the changes were nearly completed after 8h. After salting, the reduction of mass and volume ranged between $22{\sim}27%\;and\;22{\sim}35%$, respectively. Average density of the sample was found to be 0.88g/ml, and increased to 1.020g/ml after salting. Air content of the sample ranged from 0.093 to 0.120ml/ml cabbage, and about 70% of the initial content was expelled from the tissue by salting. The changes of physical properties of the cabbage during steam blanching were similar to those during salting, but their relative values were smaller. A linearization model for physical changes during salting and blanching was proposed.