• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.324-331
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• 2014

The dispersion characteristics of AlN-4.5 wt% $Y_2O_3$ powder mixture by various dispersants were investigated in ethanol and methyethly-ketone (MEK) solvents. In general, the cationic polymer dispersants demonstrated superior dispersion of the powder as compared to the non-ionic ester-type dispersants or anionic phosphate-ester-based ones. The dispersion performance of the cationic polymer dispersants was sensitive to the type of solvent. An anhydric maleic-acid-based graft copolymer dispersant, AFB-1521, demonstrated a very good dispersion capability in ethanol but exhibited a much inferior dispersion in MEK. On the other hand, the dispersion of the powder mixture was very good with a phosphate-ester-based block polymer dispersant, BYK-111, in MEK solvent, while dispersionwas much degraded in ethanol.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.170-173
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• 1963

A tri-thiocyanate molybdenum (Ⅴ) complex containing pyridine has been prepared by one step process; namely, the solvent extraction of molybdenum (Ⅴ)-thiocyanate complex into organic solvents followed by precipitation of the compound by addition of pyridine to the extract. It is concluded that the compound has a definite composition regardless of the various mole ratios of molybdenum to thiocyanate ion employed in the preparation. The use of hydrazine as the reducing agent eliminates the necessity of working under inert atmosphere and of further purification of the product. Molybdenum (Ⅴ)-thiocyanate (1:3) complex can be quantitatively and selectively extracted with slightly polar organic solvents such as ethyl acetate, and the pyridine complex is quantitatively obtained due to the insolubility of the compound in them. The oxidation state of molybdenum in the compound is + 5 and the formula appears to be $MoH_2O_2(NCS)_3Py_2$ from the contents of Mo and NCS in the compound. The solubility of the compound in various has been studied at $25^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.186-194
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• 2016

Consumption of fruits and vegetables has been conducted to be effective in the prevention of chronic diseases. In this study, 70% methanol, 70% ethanol and chloroform-methanol mixture (CM, 2:1, v/v) were used as solvents in the extraction of apple peels. The total phenol content, total flavonoid content and antioxidant activity of various extracts were investigated using in vitro assays. The extract obtained by 70% methanol showed the highest total phenol content ($20.87{\pm}0.17mgCAE/g$), ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity and ferric reducing antioxidant power. However, 70% ethanol extract possessed the strongest antioxidant activity assayed by DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and ${\beta}$-carotene bleaching method. And CM extract was found to show the highest total flavonoid content with the value of $9.26{\pm}0.06mgQE/g$. These results indicated that apple peels can be used in dietary applications with a potential to reduce oxidative stress.

• Korean Journal of Pharmacognosy
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• v.44 no.3
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• pp.242-252
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• 2013

This study was evaluated to biological activity of breeding lines from Acantopanax( A. sessiliflorus: ASF, A. koreanum: AKN, A. chiicanensis: ACS, A. senticosus: AST) and parts(root, stem, fruit, and leaf) and various extracted solvents( 100% water, 100% EtOH, 50% EtOH). Total polyphenol content of AKN root in 100% water extracts was high detected 464.46 mg/100 g. Total flavonoid content in the leaf was significantly higher than in other parts. The content of total sugars was high in the 50% EtOH extracts and fruit. The major free amino acids were arginine in all extracts. The content of arginine was detected in the root of AKN(1.807 mg/100 mg). Contents of eleutheroside B, E were high detected in 100% water extracts. Antioxidative capacity in the leaves of AKN was the higher than other extracts($EC_{50}=84.8{\mu}g/mL$). The results would be useful for understanding of the physiological properties of AKN extracts.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.41-46
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• 2017

This study aims to select suitable co-solvents and to obtain optimal process conditions in order to improve process efficiency and productivity through experimental results obtained under various experimental conditions for the etching and rinsing process using liquid carbon dioxide and supercritical carbon dioxide. Acetone was confirmed to be effective through basic experiments and used as the etching solution for MEMS-wafer etching in this study. In the case of using liquid carbon dioxide as the solvent and acetone as the etching solution, these two components were not mixed well and showed a phase separation. Liquid carbon dioxide in the lower layer interfered with contact between acetone and Mems-wafer during etching, and the results after rinsing and drying were not good. Based on the results obtained under various experimental conditions, the optimum process for treating MEMS-wafer using supercritical CO2 as the solvent, acetone as the etching solution, and methanol as the rinsing solution was set up, and MEMS-wafer without stiction can be obtained by continuous etching, rinsing and drying process. In addition, the amount of the etching solution (acetone) and the cleaning liquid (methanol) compared to the initial experimental values can be greatly reduced through optimization of process conditions.

• Advances in Traditional Medicine
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• v.9 no.4
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• pp.335-338
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• 2009

Aerial parts of Sida rhombifolia Linn. (Malvaceae) were extracted successively using various solvents and screened for various parameters of antiarthritic activity such as adjuvant-induced arthritis, motor performance, and histopathological study. The ethanol and the aqueous extracts showed potent activity; further these extracts were fractionated by using column chromatography. The fraction ET1 isolated from ethanol extract showed the most potent antiarthritic activity.

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.226-229
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• 1992

An ethanol tolerant mutant was selected by successive transfers of Clostridium thermohydrosulfuricum ATCC 33223 into the media with progressively higher ethanol concentrations. The growth kinetics of the mutant were characterized under various growth conditions. Physiological differences such as enhanced growth, tolerance to various solvents, alteration of the optimum temperature and the ratio of end products during fermentation were noticed in the mutant.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.635-639
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• 1995

The effective extraction of antioxidative substances from soybean was investigated by using various solvents, such as water, ethanol, methanol, acetone, chloroform, benzene, ethyl acetate, ether, dichloromethane, and hexane. Extraction was performed by cold method at $30^{\circ}C$ and by reflux method at $85^{\circ}C$. The antioxidative effect of the extracts was determined by peroxide value during the oxidation of soybean oil containing the extracts at $105^{\circ}C$ for 10 hours, and also by TBARS(thiobarbituric acid reactive substances) formed during the peroxidation of egg lecithin liposomes. The antioxidant activity of the extracts from raw soybean was higher than that from defatted soybean. The antioxidant activity of the extracts by reflux method was higher than that by cold method. The methanol extract from defatted and roasted soybean(DRS) showed the highest antioxidative effect against oxidation of soybean oil, while the water extract from DRS in egg lecithin liposomes. In the peroxidation of egg lecithin liposomes, the antioxidative effect of polar solvents extracts were higher than those by nonpolar solvents extracts.

• Clean Technology
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• v.3 no.2
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• pp.36-46
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• 1997

CFC and organic chlorine solvents has been used in the fine machinery and electronics industries for a long time since they have various excellent properties as cleaning agents. However, it is inevitable that alternative cleaning agents should be used since CFC and organic chlorine solvents were identified as ozone-depleting chemicals. There are various alternative cleaning agents. Among them, aqueous/semi-aqueous cleaning agents are environmentally friendly and promising in the long term. And their use and developement are on the increase in advanced countries, but few in our countries. In this paper, the charactistics and major components aqueous/semi-aqueous cleaning agents are analyzed and compared. And various cleaning equipments for aqueous/semi-aqueous cleaning agents such as immersion cleaner, ultronsonic cleaners, power spray cleaner, and vibration or rotational cleaners are compared and evaluated. Finally, important consideration points for selction of a cleaning system are analyzed and suggested in this paper.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.E
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• pp.29-38
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• 1999

This study identified emission sources and emissions of air pollutants such as volatile organic compounds (VOCs), solvents, and acid gases produced from chemical plants. We collected air samples from various processes, reactors and facilities using VOC detectors and workers' experience. We identified chemical structures and emission concentrations of air pollutants. We analyzed total emissions of air pollutants emitted from the chemical plants. Also, we developed some emission reduction technologies based on chemical types and emission situations of the identified air pollutants. For reduction of air emissions of acid gases, we employed a method improving solubility of pollutants by reducing scrubber operation temperature, increasing surface area for effective contact of gas and liquid, and modifying or changing chemicals used in the acid scrubbers. In order to reduce air emissions of both amines and acid gases, which have had different emission sources each other but treated by one scrubber, we first could separate gas components. And then different control techniques based on components of pollutants were applied to the emission sources. That is, we first applied condensation and then acid scrubbing method using H2SO4 solution for amine treatment. However, we only used an acid scrubbing method using H2O and NaOH solution for acid gas treatment. In order to reduce air emissions of solvents such as dimethylformamide and toluene, we applied condensation and activated carbon adsorption. In order to reduce air emissions of mixture gases containing acid gases and slovents, which could not be separated in the processes, we employed a combination of various air pollution control devices. That is, the mixture gases were passed into the first condenser, the acid scrubber, the second condenser, and the activated carbon adsorption tower in sequence. In addition, for improvement of condensation efficiency of VOCs, we changed the type of the condensers attached in the reactors as a control device modification. Finally, we could successfully reduce air emissions of pollutants produced from various chenmical processes or facilities by use of proper control methods according to the types and specific emission situations of pollutants.