• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.652-659
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• 2017

In the present research, in order to predict activity coefficient of inorganic ions in electrolyte solution of a petroleum system, we studied 13 components in the electrolyte solution, including $H_2O$, $CO_2$ (aq), $H^+$, $Na^+$, $Ba^{2+}$, $Ca^{2+}$, $Sr^{2+}$, $Mg^{2+}$, $SO_4$, $CO_3$, $OH^-$, $Cl^-$, and $HCO_3$. To predict the activity coefficient of the components of the petroleum system (a solid/liquid equilibrium system), activity coefficient model of Extended UNIQUAC was studied, along with its adjustable parameters optimized based on a genetic algorithm. The total calculated error associated with optimizing the adjustable parameters of Extended UNIQUAC model considering the 13 components under study at three temperature levels (298.15, 323.15, and 373.15 K) using the genetic algorithm is found to be 0.07.

• Journal of Ginseng Research
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• v.18 no.2
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• pp.122-127
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• 1994

Red ginseng extracts accounted for the major precipitating material in red ginseng drink prepared with various components and pasteuralized at $80^{\circ}C$ for 30 min. Precipitates in red ginseng extracts isolated by centrifugation were investigated for its chemical components and physicochemical properties. Recovery of precipitates in red ginseng extracts was 1.59% on a dry weight basis. Precipitates were composed of starch (71.47%), crude protein (21.75%), pectin (1.70%), polyphenol (2.97%) and calcium (3.83 ppm) but ginsenosides were not present. Absorption peak at 285 nm which appeared in red ginseng extracts was absent in the precipitates. pH and Hunter L value of the precipitates decreased, while Hunter a and b values increased in contrast to red ginseng extracts. Precipitates were solubilized to some extent in polar solvent. The shape of precipitate particle was round, sciral or irregular square. Particle size of precipitates varied from 0.17 $\mu\textrm{m}$ to 41.3 $\mu\textrm{m}$ in length.

• Transactions on Electrical and Electronic Materials
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• v.8 no.5
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• pp.211-214
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• 2007

Chemical and morphological changes of phenol formaldehyde-based photoresist after $O_2$ radiofrequency(RF) plasma treatment depending on exposure time and source power were investigated. It was found that etch rate of photoresist sharply increased after discharge turn on and reached a limit with increase in plasma exposure time. Contact angle measurements and X-ray photoelectron spectroscopy(XPS) analysis showed that the surface chemical structure become nearly constant after 15 sec of the treatment. Atomic force microprobe(AFM) measurements were shown that surface roughness was increased with plasma exposure time.

• Journal of the Korean Chemical Society
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• v.7 no.3
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• pp.207-210
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• 1963

"Astragalus Membranaceus Bunge", which is a medical herb, grows wild in Manchuria and Korea, is cultivated today in Korea. Any literature about the organic components of "Astragalus Membranaceus Bunge" has been extracted with methanol referring to a literature of "Panax Ginseng C.A. Meyer" and two kinds of colorless crystals were obtained. After recrystallization in absolute alcohol, the melting point has been measured. The one kind was $181-182^{\circ}C$ and the others, $184-186{\circ}C$ respectively. It does not contain nitrogen, sulfur and halogen. By Liebermann's reaction, the one kind was not a carbohydrate but might be a Saponin. Through paper chromatography, taste, melting point, spectrophotometry, and elemental analysis, it was concluded that the other was Sucrose. It has been notified that the compound can be crystallized at the proper temperature, purity, and concentration of the solution and also solvent system.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.1
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• pp.40-44
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• 2001

This study was carried out to investigate relationship between contents of moisture and chemical components in burley tobacco after heat treatment. Initial moisture contents of burley tobacco was 32% after cutting and casing. Burely cut tobaccos were treated at various temperature(10$0^{\circ}C$, 13$0^{\circ}C$, 145$^{\circ}C$ and 16$0^{\circ}C$) and time(0, 5, 10, 15, 20 and 30 min) in mechanical convection oven. Moisture contents of burley tobacco after heat treatment were in the range of 1.9% to 18.4%. Relationship between moisture contents and total sugar, pH, total volatile base, ammonial, L value of color, nicotine, nornicotine, and $\beta$-nicotyrine contents were positively correlated. Correlation between moisture contents and crude ash, ether extracts, 2,6-deoxyfructosazine, 2,5-deoxyfructosazine, a value of color, citric acid, m-xylene, ${\gamma}$-butyrolactone and 5-methyl-2-furfural were negative.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.64-69
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• 1998

This experiment was conducted to investigatd the variation of some apearance chemical components at National Honam Agricultural Experiment Station in Korea. the treatements consisted of five transplating times, form May 5 to July 5 at 15-day interval , and six cultivars ; two early-maturing, two mid-maturing and two latematuring cultivars. The results showed that the variatio of grain appearance such as length-wide ratio was not significantly different in early -maturing cultivars, but mid-and late-maturing cultivars made slightly a round shape of grain in case of early transplanting. Percentage of complete grain was found to be high at transplanting of MAy 20 inearly-maturing cultivars and on June 5 in mid-and late-maturing ones. PERcentage of existed embryo after milling showed high at early transplanting of May 5 for early -maturing cultivars, and at the late transplanting of June 5 in early and late maturing one. The chemical components of rice grain showed high in protein , lipid,ash and amylose content inthe earlier transplanting, and also revealed high in carbohydrates, magnesium and potassium in the later transplanting of all cultivars.

• Korean Journal of Pharmacognosy
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• v.37 no.1 s.144
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• pp.56-59
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• 2006

The vascular relaxant effets of Alpinia officinarum(Zingiberaceae) were evaluated on isolated thoracic aorta from rats. The methanolic extract of rhizome of Alpinia officinarum caused a concentration-dependent relaxation of rat aortic preparations precontracted with $0.3{\mu}M$ phenylephrine, The intensive investigation of the extract by way of activity-guided fractionation led us to yield three kind of active components, galangin(1), kaempferide(2), and kaempferol(3), which were responsible for the vasodilating property of the extract. Stuctures of the isolated active components were established by chemical and spectroscopic means.

• Bulletin of the Korean Chemical Society
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• v.20 no.6
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• pp.753-756
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• 1999

• Journal of Environmental Science International
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• v.10 no.3
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• pp.201-208
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• 2001

To investigate the physio-chemical components and properties of aerosol particles in urban area sampling of aerosol particles was carried out in the campus of Hokkaido University, Sapporo, Japan, during snowfall. Aerosol particles were collected on millipore filter papers using a low volume air sampler. Their shapes, sizes and chemical components were analyzed by a SEM(Scanning Electron Microscope) and an EDX(Energy Dispersive X-ray). As a results, ice crystals of dendrite and column types were predominantly shown at mature and developing stage of snowfall intensity. The denerite and sector plate types of ice crystals were mainly originated from the sea but column types were come from soil. Scavenging effect by snowfall was greatly also shown at dendrite type ice crystals that embryo was fully developd. Al, Si elements were shown at high frequencies as compared with others. Na, Cl components were especially shown at high frequencies under the sea-breeze wind during snowfall. Anthropogenic aerosol particles had shown with irregular shapes and sizes, relatively. Mainly 3-7$\mu$m aerosol particles were abundant and coarse particles also could be seen during snowfall. Ca, Zn, Fe components mainly caused by spike tires from vehicles in winter season were dominant before snowfall, however the element S mainly caused by human activity was rich after snowfall. The pH values of snow in Sapporo city were higher than those at coastal area. The concentration of chemical components in aerosol particles was also affected by surface winds. Aerosol particles in urban area, Sapporo were mainly affected by human activities like vehicles and combustion with wind system. And their types were related with snowfall intensity.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.883-885
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• 2009

We proposed intriguing and simple technique for fabricating flexible plastic liquid crystal (LC) devices. We made a preliminary version of a flexible LC display employing this concept, and we confirmed this technique was useful for the flexible LC display; the electro-optical reproducibility of the flexible LC device fabricated here was remarkably improved against external perturbation compared with the conventional one.