• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1243-1252
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• 2019

The purpose of this study is to investigate the optimum conditions of biomass pretreatment with potassium hydroxide (KOH) for efficient utilization of cellulose, hemicellulose and lignin from Miscanthus. The optimization of variables was performed by response surface methodology (RSM). The variation ranges of the parameters for the RSM were potassium hydroxide 0.2~0.8 M, reaction temperature 110~190℃ and reaction time 10~90 min. The optimum conditions of alkali pretreatment from Miscanthus were determined as follows: concentration of KOH 0.47 M, reaction temperature 134℃ and reaction time 65 min. At the optimum conditions, the yield of cellulose from the solid fraction after pretreatment was predicted to be 95% by model prediction. Finally, 66.1 ± 1.1% of cellulose were obtained by verification experiment under the optimum conditions. The order contents of solid extraction were hemicellulose 26.4 ± 0.4%, lignin 3.7 ± 0.1% and ash 0.5 ± 0.04%. The yield of ethanol concentration of 96% was obtained using separated saccharification and fermentation.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.11
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• pp.1011-1016
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• 2010

The $H_2S$ adsorption characteristics and property analyses of granular activated carbon adsorbent impregnated with basic solution such as NaOH, KOH, and $(CH_2CH_2OH)_2NH$ were investigated. The concentrations of NaOH and KOH reagent ranged over 1 to 5 M, The concentration of $(CH_2CH_2OH)_2NH$ was in the range of 0.1 to 1 M. Adsorption temperature($25{\sim}45^{\circ}C$) and adsorbate ($H_2S$) concentration (18.23 mg/L) were applied. The experimental results showed that the BET surface area of activated carbon impregnated with KOH decreases from $1,050\;m^2/g$ to $750\;m^2/g$, and the acidity of activated carbon impregnated with NaOH decreases from 0.541 meq/g-AC to 0 meq/g-AC, as the concentration of basic solution increases, while the pH of impregnated activated carbon increased from 9.54 to 10.94 for three basic solutions. It was also found that the $H_2S$ adsorption equilibrium capacity of activated carbon impregnated with NaOH, KOH, $(CH_2CH_2OH)_2NH$ increased with increasing temperature and $H_2S$ adsorption equilibrium capacity of the activated carbon impregnated with diethanolamine was much higher than other cases. At adsorption temperature of $45^{\circ}C$, the $H_2S$ adsorption equilibrium capacity of impregnated activated carbon was 2.0~3.3 times lager than that of pure activated carbon.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.522-526
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• 2007

Structural features and electrochemical performances of cokes pyrolized from oxidized cokes were examined, and compared with KOH-activated coke. Needle cokes ($d_{002}=3.5{\AA} $), having a graphene layer structure, were changed to a single phase of graphite oxide after oxidation treatment with an acidic solution having an $NaCLO_3$/needle coke composition ratio of above 7.5, and the inter-layer distance of the oxidized coke was expanded to $6.9{\AA} $ with increasing oxygen content. After heating at $200^{\circ}C$, the oxidized coke was pyrolized to the graphene layer structure with inter-layer distance of $3.6{\AA} $. However, the change of the inter-layer distance of the needle coke was not observed in the KOH activation process. On the other hand, an intercalation of electrolyte ions into the pyrolized coke, observed at first charge, occurred at 1.0 V, in which the value was lower than that of KOH-activation coke. The cell capacitor using pyrolized coke exhibited a lower internal resistance of $0.57{\Omega}$ in 1 kHz, and a larger capacitance per weight and volume of 30.3 F/g and 26.9 F/ml at the two-electrode system in the potential range 0~2.5 V than those of the cell capacitor using KOH-activation of coke. This better electrochemical performance may be associated with structure defects in the graphene layer derived from the process of the inter-layer expansion and shrinkage.

• Journal of Korean Society of Forest Science
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• v.35 no.1
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• pp.24-32
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• 1977

According to the chlorous salt method, most of holocellulose whose lignin was removed, was obtained. In extracting xylan from holocellulose by the different densities of alkali, 5% KOH was extracted three times but still there remained part of xylan in it and another composite of hemicellulose and cellulose was obtained. The extraction of 10% and 20% KOH showed a desirable result. Rather than the ordinary method to use a large quantity of ethanol in the precipitation isolation of xylan, the method to use a small quantity of ethanol in adopting the dialysis with cellophane-membrane by condensing density to one tenth, made il possible to extract a high purity xylan in a high retrieving rate. In isolating glucomannan, the residue of 5% KOH extraction contained a large quantity of xylan, the residue of 10% and 24% KOH extraction, also showed the same result and the comparison between glucose and mannose was approximately 1 : 1. The purification of Fehling solution made it possible to obtain comparatively pure xylan but the process of oxidation dissolution was complicated and the retrieving rate was low. This was not a good method. The ethanol titration purified a high purity xylan in a high retrieving rate and was a very excellent purifying method, considering its simple and easy process. These two purifying methods, however, could not completely remove the residue of arabinose. This will be examined and reported later.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.746-752
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• 2018

In this study, an optimized process for the waste cooking oil based biodiesel production using microwave energy was designed by using Box-Behnken design model. The process variables were chosen as a mole ratio of the methanol to oil, microwave power, and reaction time. Fatty acid methyl ester (FAME) content was then measured. Through the results of basic experiments, the range of optimum operation variables for the Box-Behnken design model, such as the methanol/oil mole ratio and reaction time, were set as between 8 to 10 and between 4 to 6 min, respectively. Ranges of the microwave power were set as from 8 to 12 W/g for 1.30 mg of KOH/g, acid value, while from 10 to 14 W/g for 2.00 mg of KOH/g, acid value. The optimum methanol/oil mole ratio, microwave power, and reaction time were reduced to 7.58, 10.26 W/g, and 5.1 min, respectively, for 1.30 mg KOH/g of acid value. Also, the optimum methanol/oil mole ratio, microwave power, and reaction time were 7.78, 12.18 W/g, and 5.1 min, respectively, for 2.00 mg KOH/g of acid value. Predicted FAME contents were 98.4% and 96.3%, with error rates of less than 0.3%. Therefore, when the optimized process of biodiesel production using microwave energy was applied to the Box-Behnken design model, the low error rate could be obtained.

• Journal of the Korean Society of Costume
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• v.15
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• pp.177-194
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• 1990

Koh(袴) was a type of dress worn on the lower part of the body which was commonly used in the Northeast Asia. It was originally used by the Northern race for the need of nomadism or hunting. The origin of the Koh which appeared in the area would be found from the trousers of the Huns who influenced in the Northeast Asia, and became in the part of the Scythian culture. The Scythians are the nomadizing race inhabited in the Northern Caucasas on the wast of the Black Sea and influenced on the inland Eurasian steppe as the first typical horse-riding race. The objectives of Koh which had been worn in the Scythian, Mongolia, Korea as well as Japan as a part of Dongho dress and ornaments and to contemplate the transmission process by cultural exchange among different races for the period from 4th century to 7th century. 1. The Origination of the Koh The Koh was originated by the environmental factor to protect the cold in the North but also from the heat in the South, and was changed and developed as gradually satisfying to the needs of the times. In the Northeast Asia the Koh was in the class of the Northern Chinese garment, and was used widely by the horse riding Scythians who moved widely from the Eurasian inland to Japan. The oldest original which could reflect the type of the Northern clothes was a pair of trousers discovered in the Huns remains of Noin Ula. This showed the exact form of hunting clothes and had a similar form with the Korean female tro-users. Since the same form of trousers drawn on the wall painting of which was excavated 4-5th century ancient Koguryo(高句麗) tomb was the same form the trousers of Noin Ula seemed to be the original form of Koh in the Northeast Asia. 2. The Chinese Trousers It was the time of the King Mooryung(武靈王) in the Cho(趙) Dynasty B.C. 3th century that the trousers used regularly in China. However, the Koh had been used as undergarment which functioned for the protection of the cold not the horseriding garment. The trousers seemed to be not very obviously shown off since the Poh (袍) was long, but mainly used by the people from lower class. As people learned the adapted the trousers. It was essential for the times of war and quarrel. The king himself started wearing the Koh. The Chinese trousers were influenced by the Huns, the Northern clothes of the Scythian culture, and similar to the Korean clothes. 3. The Korean Trousers Korean was a race bared from the Eastern foreign group. It was obvious that the clothes was Baji-Jeogori(바지 저고리), the garment of the Northern people. This had the same form of the Scythian dress and ornaments which was excavated from the Mongolian Noin Ula. The Scythian dress and ornaments were influenced from the Ancient West Asia Empire and transmitted to the Northeast Koguryu by the horseriding Scythian. The trousers were kept in the traditional style by the common people in Korea were transmitted to Japan which were for behind in cultural aspect, as well as got used to the Chinese as the efficient clothes though active cultural exchange. 4. The Japanese Trousers The ancient Japanese clothes were influenced by the Southern factor but not the form of the Koh. As the Korean people group was moving towards Japan and conquer the Japanese in the 4-5th century, however, North Altaic culture was formed and at the same time the clothes were also developed. The most influenced clothes at this time were those of Baekge(百濟) and the trousers form called Euigon became the main form. Because of the climatic regional factor, it was tied not at the ankle but under the knee. From the view the ancient Japanese clothes disappeard about that time, it could be due to the conquest of the culturally superior race but not the transmission of the culture. In the latest 7th century both the Chinese and Japanese dress forms were present, but the Dongho(東胡) dress and its ornament from Korea was still the basic of the Japanese dress form.

• 한국문화재보존과학회:학술대회논문집
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• 2003.09a
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• pp.75-75
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.311-312
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• 2009

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.148-148
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• 1996

• Journal of Korean Society of Water and Wastewater
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• v.23 no.4
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• pp.385-394
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• 2009