• Ecology and Resilient Infrastructure
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• 제5권1호
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• pp.19-24
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• 2018

Water quality is affected by the pollutants flowing into rivers since the interaction between water bodies and sediments in various environmental conditions. Especially, accumulation of sediments increases in the stagnant water areas due to a relative long hydrological retention time in the water bodies. Therefore, it is an important factor of water quality to understand characterization of the material behavior in water bodies and sediments. In this study, the objective of the conditional experiments was small and medium sized streams located in Gyeonggi-do. To estimate how the changes of fluoride behavior, depending on the pH, ion type, concentration, and clay contents. The pH results showed a trend that adsorption amount of fluorine decreased and the dissolution of fluorine increased following by pH increasing. The concentration and type of ions results showed that $Cl^-$ and $SO{_4}^{2-}$ ions had no significant effect on the adsorption ability of fluorine, the amount of dissolution was increased because $OH^-$ ion had active competition with fluorine in the reaction. The ingredient of sediment results showed that the amounts of fluoride adsorption and dissolution were reduced in samples, which contain relatively large amounts of Silt and Clay components. This means that the environmental conditions of water bodies greatly affect the adsorption and dissolution of fluoride in the sediments, so that proper management of fluoride in the sediments must precede an understanding of the environmental conditions of the water bodies.

• Korean Journal of Food Science and Technology
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• 제18권6호
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• pp.497-502
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• 1986

Soaking of soybeans is usually considered necessary as a part of further processing. However the soaking process causes the loss of soluble solids from soybean. The temperature effect on the leaching rate of soluble solids during soaking of soybeans were determined at temperatures ranging from $10^{\circ}-50^{\circ}C$. Soaking temperature and time were found to greatly influence the content of soluble solids. Solid leaching rate constant was increased with temperature ranging from 10 - 33 mg/min. Overall mass transfer coefficient of $66.7\;mg/m^2{\cdot}h$ at $20^{\circ}C$ for Saeal variety was higher as compared with other variety (Kwanggyo, Tanyob), and activation energy was found to be 4026 cal/mole. Z-values to reach different degree of leaching showed the descending tendency with increase of solid leaching.

• Analytical Science and Technology
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• 제11권5호
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• pp.394-399
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• 1998

This study was carried out to characterize the chemical composition and leaching properties of heavy metals in coal fly ash, which was generated from Korean electrical power utilities in several million tons per year. Comparion with respect to the leachability of heavy metals between the Korea standard leaching test (KSLT) and the American Environment Protection Agency (EPA) method 1311 (TCLP: Toxicity Chracteristic Leaching Procedure) was performed. The concentration of Ag, As, Ba, Cd, Cr, Cu, Pb, Se, Hg in the leacheate was determined by ICP-MS. The analytical result showed a significant difference of the leachability according to the characteristics of the leaching solution except Se, suggesting the necessity of improvement in the leaching test method that is currently implemented in Korea.

• Journal of Radiation Protection and Research
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• 제10권2호
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• pp.113-121
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• 1985

For the safety assessment of radwaste treatment and disposal, the leaching characteristics of $Cs^+\;and\;Sr^{++}$ from the cement-solidified radwastes was investigated by means of the survey and analysis of the activity leach rate and cumulative leach fraction of $^{137}Cs\;and\;^{90}Sr$ leaching from solidified radwastes. The cylindrical cement-solidified samples were made by the sodium silicate method and neutralization method changing the mole density of simulated liquid radwaste, type of cement, adding material and concentration of boric acid. The leaching study was carried out by the method using simulated PWR concentrated liquid radwaste solidified in cement that had been processed following the recommendations of IAEA. All the experimental results are in well accordance with the research data reported previously, but the watertight cement-solidified radwastes show rather high leach rate of radioactivity. It is learned, therefore, that the watertight cement is not adequate as the material for the solidified radwastes.

• Journal of the Korean GEO-environmental Society
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• 제7권4호
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• pp.35-41
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• 2006

This paper analyzed elution and ingredients of soil components which consist of soil and rocks in 6 regions in Yeongyang and Cheongsong to identify substantial matters that cause muddy water in Imha reservoir. We identified that more than 80% of major ingredients in collected soil and rocks are vermiculite(V), illite(I), kaolinite(Ka), quartz(Q), feldspar(F). Sodium and calcium are eluted in large quantities from soil of Sanseong and Cheongki. When calcium is in contact with water, much ions are eluted rapidly. We confirmed these ions are alkali minerals rising pH. We consider clay components distributed in Yeongyang as major cause of muddy water and rising pH of Imha reservoir because its ingredient calcite easily is dissolved in rainwater and splits other mineral particles into ${\mu}m$ sized particles.

• Journal of the Korean Applied Science and Technology
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• 제32권1호
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• pp.116-126
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• 2015

The present study utilized a shuttle mechanism of wet chemical absorption using MEA. In addition, industrial by-products containing a large amount of inorganic alkali substances were utilized for wet carbonization process. Chemical pretreatment of industrial by-products extracted calcium ions. ICP result of calcium ion was obtained up to 17,900 ppm(17.9%) by acidic substance. And also, In this work, 94% of recovery rate was obtained using wet MEA absorption process from $CO_2$ flow at the ambient condition. Through the liquid carbonation process, a sludge was fixed with rate of 0.175 mg of $CO_2$ per mg of sludge. It was found from XRD results that the structure of final product was composed of a calcite structure which is general structure of $CaCO_3$.

• Korean Journal of Soil Science and Fertilizer
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• 제35권5호
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• pp.264-271
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• 2002

Nitrogen releasing characteristics of polymer-coated urea(PCU) that made acrylic synthetic resins were studied in incubated soil, water and paddy soil. Also, their correlations and degradation patterns of coating material were tested. Releasing rate of nitrogen from PCU decreased with increasing coating rate. N001(coating rate 8.5%) and N003(coasting rater 6.3%) were low releasing amount at the early stage, whereas N005(coating rate 4.8%) was released over 80% within 20 days. Relationship of the releasing rate between incubated soil($25^{\circ}C$) and paddy soil could be described as follows : $Y=-0.0011X^2+2.2931X-50.264(R^2=0.9884)$ for N001, $Y=-0.0016X^2+1.1587X+5.5064(R^2=0.9805)$ for N003 and $Y=-0.03X^2+6.499X-243.22(R^2=0.9422)$ for N005, respectively (Y: release rate at field condition, X: experiment period). Relationship of the releasing rate between incubated water($30^{\circ}C$) and paddy soil can be described as follows : $Y=0.0011X^2+2.2601X-25.329(R^2=0.9884)$ for N001, $Y=-0.0306X^2+4.4994X-76.307(R^2=0.955)$ for N003 and $Y=-0.0164X^2+3.7764X-108.22(R^2=0.9422)$ for N005. After 150 days, coating materials of N001, N003, and N005 in incubated soil were degraded approximately 23%, 22% and 15%, respectively. Also The scanning electron microscope examination of coating material revealed that particle surface became gradually shattered with the time after the soil treatment.

• Economic and Environmental Geology
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• 제56권4호
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• pp.409-419
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• 2023

Acid mine drainage(AMD) treatment is classified as both passive and active treatment. During the treatment, about 5,000 tons of neutralization sludge is generated as a by-product per year in Korea. This study was conducted to evaluate the characteristics of sludge generated from physico·chemical treatment processes as an active treatment from 5 different sources (D, H, S, T, Y) and the possibility of the sludges being recycled. The sludges have a pH range of 5.86 ~ pH 7.89, and a water content range of 51% ~ 82%. Most of particle sizes were less than 25 ㎛. In analysis of inorganic elements, the concentration of Al, Fe, and Mn were between 1,189 mg/kg ~ 129,344 mg/kg, 106,132 mg/kg ~ 338,011 mg/kg, and 3,472 mg/kg ~ 11,743 mg/kg, respectively. The concentration of As and Zn in sludge-T, Cd in sludge-D, Ni in sludge-H, Zn in sludge-S, and Cd in sludge-Y exceeded the soil contamination standards of Korea. The results from 2 separate kinds of leaching test, the Korea Standard Leaching Test(KSLT) and Toxicity Characteristic Leaching Procedure(TCLP), showed that all the sludges met the Korea groundwater standards. From the XRD and SEM-EDS analysis, the peaks of calcite and quartz were found in the sludges. The sludge also had a high proportion of Fe and O, and the majority of the composition was amorphous iron hydroxide.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 한국결정성장학회 1997년도 Proceedings of the 13th KACG Technical Meeting `97 Industrial Crystallization Symposium(ICS)-Doosan Resort, Chunchon, October 30-31, 1997
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• pp.93-97
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• 1997

$CO_2$ gas를 초임계상태의 유체로하고 그 용매에 코팅물질인 파라핀을 용해시켜 초임계 분출법(RESS)에 의해 핵입자 코팅을하여 복합입자를 제조하였고 그 용출 특성을 고찰하였다. 핵입자로는 입도분포가 다른 Glassb eads, Brilliant Blue(이하 BB)를 피복한 Glass beads, 분무건조법으로 제조한 염기성 탄산마그네시아의 Microcapsule(이하 MHC MC)을 사용하였다. 제조된 복합분체 표면을 SEM으로 관찰하였고 FT-IR을 사용하여 표면의 성분분석을 하였다. BB로 피복시킨 Glass beads는 Spectrophotometer로 BB가 용출되는 시간을 측정하였고 AA로 MHC MC중 Mg2+ ion의 release time이 7min, 26min, 30min으로 반응부에서 포집한 시료의 용출특성이 제일 우수하였다.

• Journal of Pharmaceutical Investigation
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• 제8권2호
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• pp.11-17
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• 1978

Phenobarbital의 용출속도(溶出速度)를 증가시키기 위하여 PVP와의 공침물(共沈物)을 형성(形成)한 후 일정(一定)한 표면적(表面積)하에서의 용출속도(溶出速度)를 비교검토(比較檢討)하였다. $37^{\circ}C$, 150r.p.m${\times}$에서의 rate constannt of dissolution, k,는 phenobarbital이 $8.75{\times}10^{-6}M/min$, 1 : 2 phenobarbital-PVP coprecipiate는 $5.35{\times}10^{-5}M/min$이었으며, activation energy of dissolution, Ea는 phenobarbital이 약 10,600cal/mole coprecipitate는 약 5,800cal/mol이었다. 그리고 X-ray diffraction study에 의(依)하면 페노바르비탈 단일물질(單一物質)이나, PVP와의 physical mixture에서는 페노바르비탈의 결정피크를 나타내었으나, PVP와의 공침물(共沈物)의 경우(境遇)에는 페노바르비탈의 결정피크를 인지(認知)할 수 없었다.