• Resources Recycling
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• v.29 no.6
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• pp.65-72
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• 2020

Black dross is a dark gray dross generated during the aluminum recycling process that uses flux, and contains NaCl, KCl, Al2O3, MgO, etc. Black dross is separated into soluble substances (NaCl, KCl) and insoluble substances (Al2O4, MgO) through the dissolution process. Soluble materials can be reused as salt flux, and Al2O3 and MgO can be upcycled to various ceramic materials through the synthesis process. In this study, Mayenite was synthesized using Al2O3 and MgO recovered from black dross, and the synthesis was performed according to the mixing ratio and reaction temperature. It was confirmed that when Mayenite was synthesized using black dross (spinel) and CaCO3, precursors were changed to Mg0.4Al2.4O4 and CaO at 700 ℃, and to Ca12Al14O33 (Mayenite) after 800 ℃. In the mixing conditions experiment, it was confirmed that the Mayenite XRD peak increased with increase of the CaCO3 content, and the Mg0.4Al2.4O4 XRD peak decreased. As a result of the BET analysis of the synthesized powder, the surface area decreased as the fine particles were grown and agglomerated in the process of generating mayenite.

• Journal of Dairy Science and Biotechnology
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• v.22 no.1
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• pp.13-25
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• 2004

High concentration of cholesterol in the blood streams of humans has been recognized as a risk factor in the coronary heart disease. Recently, lactobacilli having high bile salt hydrolase activity have been claimed to decrease the concentration of the blood stream cholesterol in humans. In particular, many studies have been reported on the hypocholesterolemic effect of Lactobacillus acidophilus, a normal component of the microflora of the small intestine. Bile salts are excreted as bile into duodenum in the form of N-acyl compounds conjugated with glyine or taurine. Bile excretion is the major route of eliminating cholesterol from the body as well as one of the important pathways of cholesterol metabolism. Since conjugated bile salts are necessary to emulsify cholesterol, deconjugation of bile salts by lactobacilli could decrease intestinal absorption of cholesterol. Free bile salts as well as cholesterol are less soluble than the conjugated bile salts. Therefore, few free bile salts and cholesterol are absorbed through the enterohepatic circulation and most of them are easily excreted via feces. Thus, serum cholesterol could be removed from the body pool by synthesizing new conjugated bile salts to replace the excreted ones.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.351-358
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• 2012

To investigate the environmental adaptation and ecophysiological characteristics of Suaeda maritima and S. asparagoides under saline conditions, plant growth and density were analyzed according to environmental changes of habitats. The total ion content of soil decreased with time, which was caused by the predominance of exchangeable $Na^+$ and $Cl^-$ in the upper layers. The population of S. maritima was more densely distributed in the region with higher ion contents of $Cl^-$, $Mg^{2+}$, $K^+$ and $Na^+$ than the population of S. asparagoides. Both species were showed a decreased population density according to increases in plant growth. Under the conditions of a salt field, S. maritima and S. asparagoides contained high inorganic ions to maintain low water potential, but low water soluble carbohydrate contents. In the case of free amino acid, S. maritima showed an especially high proline content, and contained rather large amounts of free amino acids, whereas S. asparagoides did not. Both species showed high inorganic ion contents in the leaves, which might be a mechanism of avoiding the ionic toxicity by diluting the accumulated ionic concentration with a high ratio of water content to dry weight. This result suggests that S. maritima seems to adapt to saline conditions by accumulating proline in addition to inorganic ions. S. asparagoides seems to adapt by osmoregulation processes, using inorganic ions rather than free amino acids.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.296-300
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• 1998

The analysis of biochemical changes in tobacco plant as increase of NaCl concentraion was conducted. Total protein content and soluble protein content were decreased as NaCl concentration was increased, in that steady decreased until 120mM NaCl and largely decreased at 150mM NaCl. The expression of 74Kd subunit was increased until 60mM NaCl. However, the amount of 74Kd protein was decreased from 90mM NaCl. There was no difference for expression of other protein subunits. Chlorophyll a content was significantly decrease as NaCl concentration was increased, but chlorophyll b content was not much decreased. The slow increase up to 120mM NaCl and large increase at 150mM NaCl for ATPase and peroxidase activities indicated that 120mM NaCl could be a limiting concentration for salt injury.

• Magazine of the Korean Society of Agricultural Engineers
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• v.20 no.2
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• pp.4695-4707
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• 1978

The objeative of this study is to study how to rapidly convert tidal land into cultivable land. The study of a rapid, reasonable desalinization method is conducted at Namyang tidal land which represents soil texture of tidal lands along the south west costa larea of Korea. Therefore, Researches were made at many Pilots in order to find a way of high efficiency of leaching with simpler facilities and cheaper costs. The results of study are briefly summarized as follaws: 1. Subdrainage efficieny is 35%. This is a Poorly drained area, and needs longer leaching desalinization period. 2. The efficieny of desalinization in P.V.C 16 meters plot is the same as that of mole drainage 2 meters plot. P.V.C 4 meters plot has desalinization effect as much as two times compared to P.V.C 16 meters plot. 3. Because the soil texture is silty-clay, desalinization in non-treated plot of sub-drainage and surface drainage desalinization take three times longer period in comparision with P.V.C 4 meters plot. 4. As to the desalinization rate of soluble salt in the soil, the efficieny of desalinization of the topsoil in P.V.C plots was 50% higher than that of mole drainage plot and about 170% higher than that of non-treated plot. In the deep soil salt accumulation at topsoil was observed in non-treated and mole drainage plots, but efficiency in P.V.C polt is about 40 times as high as that of mole drainage and non-treated plot. 5. As to the results of use gypsum and lime as sub-drainage soil improver, gypsum was 60% more efficieny than lime in the continuously inundated plot and 44% in the intermittently inundated plot. The efficieny of gypsum and lime in the intermittently flooded plot is 35% and 42% higher than that of continuously flooded plot reapeaticee1y.

• Journal of Conservation Science
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• v.25 no.2
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• pp.131-145
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• 2009

Goryeong Yangjeondong Petroglyph on the joint face of the bedrock (6m in width, 3m in height) composed of the green sandstone has circles and shield pattern sculptures. The rock is mainly composed of quartz, feldspar, chlorite, illite and calcite with the clay minerals. These clay minerals occur as pore lining, replacement of component and pore fillings. Investigated the weathering aspects including the connection between soluble salt and rock weathering and the stability of the bedrock with petroglyphs. The Major deterioration aspect are grain peel-off, surface exfoliation, cracks and damage. And the bedrock where the joints and cracks advance is interpreted with the fact that has the possibility of the falling rock. For conservation, adhesive need to cover crack and damage and consolidation is necessary in the surface which becomes weak.

• Journal of Korean Elementary Science Education
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• v.22 no.2
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• pp.138-148
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• 2003

This study was to analyze how elementary school science textbooks explain dissolution and to examine the patterns of elementary school teachers' conceptions on dissolution and the teaching practices on dissolution of elementary school teachers. According to the result of the textbook analysis, the textbooks based on the 7th curriculum didn't explain dissolution very differently from those based on the 6th curriculum. The contents dealing with dissolution in the textbooks of 7th curriculum became difficult gradually as the year went up, but the connected organization of the contents made students learn it easily. For example, in order to learn dissolution introduced first in the 3rd year 2nd semester textbook, students would tell soluble substance in water from insoluble substance in water as they put powdered substance in water. In the 5th year 1st semester textbook students were supposed to acquire the knowledge related to dissolution through the designed activities such as comparing solubility produced by different solvents and defining a solvent, a solute, dissolution, and a solution. In addition, teachers' guide for 5th year 1st semester textbook elucidated the principle of dissolution using attraction concept that was scientific. The result of the survey on teachers showed that 90% of elementary school teachers understood the dissolution of salt in water just as millet particles' filling the space between bean particles and they responded that they demonstrated millet particles' filling the space between been particles when they taught the dissolution of salt in water. When it comes to teachers who had the right idea on dissolution as the attraction conception, understanding was one thing and teaching was another, because they often instructed dissolution as the space conception in the real teaching.

• Polymer(Korea)
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• v.35 no.6
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• pp.558-564
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• 2011

The biocompatibility and biodegradability of poly(amino acid) make them ideal candidates for many bio-related applications. Poly(aspartic acid), PASP, is one of synthetic water-soluble polymers with proteinlike structure, and has been extensively explored for the potential industrial and biomedical applications due to its biodegradable, biocompatible and pH-responsive properties. In this work, amino acid-conjugated PASPs were prepared by aminolysis reaction onto polysuccinimide (PSI) using ${\gamma}$-aminobutylic acid(GABA) and ${\beta}$-alanine methyl ester and a subsequent hydrolysis process. Their chemical gels were prepared by crosslinking reaction with ethylene glycol diglycidyl ether (EGDE). The hydrogels were investigated for their basic swelling behavior, hydrolytic degradation and morphology. The crosslinked gels showed a responsive swelling behavior, which was dependent on pH and salt concentration in aqueous solution, and relatively fast hydrolytic degradation.

• Journal of Radiation Industry
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• v.9 no.4
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• pp.199-207
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• 2015

Typical radiation cross-linked hydrogels has the characteristic that high water content, but low emission efficiency of active ingredients. Therefore, the hydrogel was prepared by the addition to collagen, which is closely related to the formation of skin wrinkles in biocompatibility and highly water-soluble carboxymethyl cellulose sodium salt (CMC) in order to preparation of hydrogels has excellent emission efficiency of active ingredients. Hydrogels were prepared by dissolving CMC and collagen each of 0.5%, 10% concentration in deionized water. Then, prepared hydrogels are performed by gamma-radiation at 1, 3, 5 kGy irradiation dose. The results showed that the gel fraction of after irradiated 3 kGy hydrogel was higher than before irradiated gelation as long as the 55.3%. The swelling rate of irradiated 3 kGy hydrogel was lower than the non-irradiated sample. The compressive strength of 3 kGy irradiated hydrogel was the highest. The visco-elastic did not show any significant differences, even after irradiation. The CMC hydrogel in this study suggested a potential use as a material for the mask pack for improved emission efficiency of the active ingredient and anti-wrinkles.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.657-662
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• 2005

Extractions fro fertilizer and soil samples were performed to yield the operationally defined fractions 'soluble' chromate (extractable with $NH_4NO_3$), 'exchangeable' chromate (extractable with phosphate buffer pH 7.2), and these results were compared with the data obtained by extractions with ammonium sulfate, borate buffer pH 7.2, saturated borax pH 9.6, and polyphosphate (Graham's salt). In order to maintain the pH of extractant solution about constant, the concentration of extractant buffer had to be raised to at least 0.5 M. The results strongly depended on the kind of extractant, and the solid: liquid ratio. For most of the samples investigated, the extraction efficiency increased in the order borate-sulfate-nitrate-phosphate. Whereas the recovery of $K_2CrO_4\;and\;CaCrO_4$ added to the samples of basic slags prior to the extraction was about complete, the recovery of added $PbCrO_4$ was highly variable. In soil extracts, the color reaction was interfered from co-extracted humics, which react with the chromate in weak acid solution during the time period necessary for color reaction (1 hour). However, this problem can be overcome by standard addition and subtraction of the color of the extractant solution. In soil extract of about pH < 7, organic material reduced chromate during the extraction period also, and standard addition of soluble chromate is recommended to prove recovery and the stability of chromate in the samples. In admixtures of soils and basic slags, results for hexavalent chromium were lower than from the mere basic slags. This effect was more pronounced in phosphate than in nitrate extracts. As a proficiency test, samples low in organic carbon from contaminated sites in Hungary were tested. The results from $NH_4NO_3$ extracts satisfactorily matched the results of the Hungarian labs obtained from $CalCl_2$ extractants.