• YAKHAK HOEJI
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• v.1 no.1
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• pp.4-6
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• 1948

The fruits of Rhus javanica L. distributed widely in Korea were extracted with cold water, the filtered clear liquid was evaporated and from the residue large colorless columns, M.P.about 180.deg., were obtained by recrystallisation from hot water. On being incinerated it left a considerable amount of solid residue consisting of calcium. Its aqueous solution which had a strong acid reaction was acidified with sulfuric acid, the precipitate, CaSO$_{4}$, was filtered off, the filtrate was evaporated and from the residue colorless needles, M.P.98-100.deg., were obtained by treating with alcohol. It was identified to be malic acid by determining the mixed melting points of itself and its p-bromphenacylester with authentic specimens. Thus the original substance was proved to be a kind of Ca-salt of malic acid.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 1994.06a
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• pp.41-49
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• 1994

The meanings, classification, and regulatory status of 'natural food colorants' are discussed. Nowadays the technological advances for processing Cochineal color is flourishing here and aboard, makes highly concentrated products (e.g., 95% Carminic acid) is comercially available. Application of carminic acid for a food system needs target-specific formulation, mixing with alumn, tartaric acid, and other salts to stabilize the color hue in food system. On the other hand, carmine, the aluminium-lake of carminic acid, is more convenient product to be used and would give more strong color. Of these reasons Carmine is much popular product than Cochineal extract in Western and European countries. We insist that carmine should be also certified as natural colorant together with Cochineal extract in Korea. Authors expect that several kinds of anthraquinone colorant (Lac and Kermes) would be introduced in Korean market in near furture.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.337-339
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• 2003

The technology removing radionuclides from soil using soil washing was studied. The main radionuclides contaminated in the soil are Cs$^{137}$ and Co$^{60}$ . It is suitable that scrubbing time is 4 hours and a mixing ratio of soil weight and washing solution volume is 1:10. more than two times continuous scrubbing method with 0.5 M oxalic acid was needed to remove Cs$^{137}$ and Co$^{60}$ from soil more than 70%. Radionuclides removal efficiencies of recycling washing solutions recycled with strong acid resins until 5 times are similar to that of 0.5 M oxalic acid.

• Journal of Integrative Natural Science
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• v.3 no.2
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• pp.112-116
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• 2010

Prepared CdSe nanoparticles were systems, one of the most studied and useful nanostructures. Semiconductor quantum dots (QDs) have been the subject of much interest for both fundamental reseach and technical applications in recent years, due mainly to their strong size dependent properties and excellent chemical processibility. CdSe nanocrystals were synthesized by using sol-gel process. Synthesized CdSe quantum dots were studied to evaluate the optical, electronic and structural properties using UV-absorption, and photoluminescence (PL) measurement. Prepared CdSe nanoparticles were subjected to sense hydrofluoric acid. Photoluminescence was quenched upon adding of hydrofluoric acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.6
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• pp.582-589
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• 1991

The effects of types of soybean sauceI(SS) and additives for soybean sauce(AS)on the antioxidative activity was studied. The values of peroxides(POV) and thiobarbituric acid (TBA) were monitored under the oxidation systems of linoleic acid or ground cooked meat. Among 10 types of SS including Korean treditional SS, Koran M company's raw SS, Korean koikuchi, Korean acid hydorlyzed SS, Korean mixed SS, Korean decolorized SS, Japanese tamari, koikuchi, usuguchi, and Japanese white SS, three SS types of Japaness tammari, koikuchi and Koran raw SS were found to have the most strong antioxiative activity. However, various as such as monosodium glutamate, caramel, fructose syrup, malt syrup and paraoxybenzoic acid (POBA) were appeared to accerlerate oxidation. Possibly an important antioxidative cahracteristics was due to its higher concentration of nitrogen and melanoidin.

• Korean Educational Research Journal
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• v.37 no.1
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• pp.33-45
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• 2016

We propose a research for detection of the fluoride ion using borane compounds. Based on the Lewis acid-base reaction, we discussed the fundamental of sensing for fluoride ion. One of the important aspects in the chemistry of organoboranes is their behaviors as Lewis acids, which is a result of the vacant $2p_{\pi}$ orbital on the tricoordinate boron center. The electronic interaction between boron atoms and ${\pi}$-orbitals of donor molecules, constructed from the carbon 2p orbitals, is generally strong. Boron atoms can reach the desired octet configuration either through ${\pi}$-overlap with a suitable X or through formation of Lewis acid-Lewis base complexes.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.719-722
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• 2004

Resins using recycled PET offer the possibility of a lower source cost of materials for making useful polymer concrete products. The purposed of this paper is to form a part of reducing the damage of sulfuric acid, through investigating recycled PET polymer concrete, . immersed at sulfuric acid solution for 84 days. Recycled PET PC is excellent chemical resistance, resulting in the role of unsaturated polyester resin which consists of polymer chain structure accomplishes bond of aggregates and filler strongly. Also, Recycled PET PC, used fly-ash as filler, is stronger resistance of sulfuric acid corrosion than $CaCO_3$, because it is composed of $SiO_2$ and very strong glassy crystal structure. Therefore, Recycled PET PC, used fly-ash as filler, is available under corrosion circumstances like sewer pipe or waste disposal plant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.73-80
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• 2006

Sesame (Sesamum indicum L.) seeds contain abundant oil and antioxidative lignans related to the seed quality. To evaluate the potential effects of drought stress on the chemical composition of sesame seeds, eighteen cultivars were imposed water-deficit condition by withholding irrigation during 15 days at podding and maturing stage, compared with well-watered plants as control in seed yield and chemical composition. Drought treatments showed great decrease of seed yield with not affecting seed weight. The contents of sesamin and sesamolin decreased while lignan glycosides inversely increased in response to drought stress. Oil content was not significantly changed by drought treatment in spite of its slight decrease. In case of fatty acid composition, there were significant differences in increase of oleic acid while inverse decrease of linoleic acid under drought stress condition. These results demonstrate that the chemical composition of sesame seed may be modified with drought stress. In particular, the increase of sesaminol glucosides with strong antioxidative activity was observed.

• Bulletin of the Korean Chemical Society
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• v.1 no.3
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• pp.101-104
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• 1980

A sequential copolypeptide with repeating unit sequences, in which a glycyl residue is flanked progressively by two ${\gamma}$-benzyl-L-glutamyl residues, has been synthesized by poymerizing p-nitrophenyl ester of ${\gamma}$-benzyl-L-glutamyl-${\gamma}$ -benzyl-L-gutamyl-glycine. Polymers obtained were characterized by viscosity and infra-red spectral data. The highest molecular weight obtained was 21,000. Molecular conformation in solid state was found to be a mixed form of and |${\beta}$-structure. Polymers obtained were insoluble in the most of the organic solvents except in a strong acid like dichloroacetic acid, but in binary mixtures of solvents such as dichloroacetic acid-ethylene dichloride or dichloroacetic acid-chloroform, they were soluble within certain ranges of solvent compositions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.21-22
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• 2022

In order to improve the strength degradation of the cement-based material to which strong alkaline liquid red mud was added, the liquid red mud was neutralized with sulfuric acid and added to the cement paste to examine the mechanical properties according to the amount added. As a result of measuring the compressive strength, the strength was higher when the red mud was neutralized with sulfuric acid and added to the cement paste than the cement paste to which the liquid red mud was added. As a result of hydration heat measurement, when red mud was neutralized with sulfuric acid and added to the cement paste, an initial strength higher than that of liquid red mud was expressed.