• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.229-240
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• 1987

Carbonation of concrete is one type of a chemical process. The reaction mechanism is very complex for the case when low-calcium fly ash and blast furnace slag is added. When fly ash and blast furnace slag is used as an admixture in concrete, they improve compressive strength in the long term, permeability and chemical resistance of concrete by a pozzolanic reaction and latent hydraulic property. On the other hand, the pozzolanic reaction of fly ash and latent hydraulic property of the blast furance slag leads to a reduction of the alkalinity of the concrete. It has been pointed out that this will accelerate the carbonation of the concrete and the corrosion of reinforcement steel embedded in the concrete. In order to clarify the effect of fly ash and blast furance slag on the carbonation of concrete, an accelerated carbonation testing of concrete was carried out by varying the conditions of concrete and the initial curing period in water. The test results of accelerated carbonation were compared to the carbonation test results of concrete stored for 15 years in open air, but protected from rain. As a result, the equation for the rate of carbonation based on compressive strength of concrete was proposed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.895-900
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• 1998

In order to the effective utility of marine by-product, crude lecithin was isolated from skipjack viscera oil and the lecithin was refined by bleaching and deodorization. Crude lecithin was separated from the skipjack viscera oil degummed with 0.4 ml of citric acid per 100 ml of the oil. Bleaching was effected by adding $5\%$ activated clay and treating for $40^{\circ}C$ for 90 min under vacuum, and deodorization was effectively conducted by steam distillation at $130^{\circ}C$ for 60 min under 4 ton of vacuum. The major fatty acids of the skipjack viscera oil. were 16:0. 18:1 (n-9), 22:6 (n-3), 18:0, and 16:1 (n-7). Crude and refined lecithins contained more aproximately $7\~18\%$ of 22:6 (n-3) than raw oil, the skipjack viscera oil.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.61-74
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• 2012

Industrial complexes in Korea have been vigorously established by economic development plan and development policy of industry in 1960s. Recently, Korean government has promoted Eco Industrial Park (EIP) project to recycle by-products and wastes in industrial park In this study, we analyzed the physical and chemical properties for the sludges discharged from A industrial complex. And we investigated the economic feasibility and environmental impact of sludge to energy facilities. The analysis results indicated that the petrochemical industry were 92% in sludge production, the highest treatment amount was landfill, followed by incineration and recycling and then ocean disposal. Wastewater sludge and process sludge samples are collected and analyzed to use as basic data on economic feasibility and environmental impact. Weighted average heating value of sludge samples was 3,891kcal/kg. Based on this data, installation and operation costs, operation returns of operating the drying facility are estimated, compared with cogeneration facility. And this study examines how the payback period of each simulation(total 8 case) with the important parameter changes. As a result, it was found that what needs the shortest payback period is 3years with connection of drying facility and cogeneration facility based on the government's financial subsidy system.

• Journal of Life Science
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• v.12 no.1
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• pp.1-7
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• 2002

The purpose of this study was designed to observe the effects of the feeding Zizyphus jujuba seed extract on the improvement of the blood glucose, lipids in the serum of streptozotocin (STZ)-induced diabetic rats fed the experimental diets for 4 weeks. Concentrations of blood glucose, total cholesterol, atherosclerotic index, LDL, LDL-cholesterol, free-cholesterol, cholesteryl ester, triglyceride (TG) and phospholipid (PL) in serum were significantly higher in the STZ (55mg/kg B.W.)-induced diabetic group (group 2) and STZ (I.P.)+ Zizyphus jujuba seed extract group (group 3) than those in the control group (group 1, basal diet + water). But the concentrations of blood glucose, total cholesterol, atherosclerotic index, LDL, LDL-cholesterol, free-cholesterol, cholesteryl ester, TG and PL in serum were remakably lower in the group 3 than those in the group 2. In the ratio of HDL-cholesterol concentration to total cholesterol and HDL-cholesterol concentration, Zizyphus jujuba seed extract administration group (group 3) were higher percentage than in the group 2. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) in serum were rather lower in the Zizyphus jujuba seed extract administration group (group 3) than in the STZ- induced diabetic group (group 2). From the above results, it was suggested that the Zizyphus jujuba seed were effective on the improvement of the blood glucose, lipid compositions in serum of STZ-induced diabetic rats. Moreover, in Zizyphus jujuba seed was effective therapeutic regimen for the control of metabolic derangements in adult disease.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.570-576
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• 2002

For the utilization of the by-products of whelk processing, whelk internal organ with the addition of commercial proteolytic enzymes - Flavourzyme, Neutrase, Protease NP, Prozyme - were used to make jeotgal, Korean traditional salted and fermented seafood sauce. The products were prepared at salt concentration of 25% with enzyme contents 0.05 and 0.1%. The samples were stored at $10^{\circ}C$ and the chemical properties were evaluated for 6 months. The pH in all samples were decreased from near 6.8 in the beginning stage to 6.1-6.4 in the final stage of incubation. Amino nitrogen of jeotgal increased with enzyme concentration and showed maximum value, 646 mg%, at 0.1% of Flavourzyme. Total nitrogen content was increased till four months, but rapidly decreased after that. Protein degradations of whelk internal organ during maturation of jeotgals were investigated by SDS-PAGE. The patterns of degradation were different with added enzymes.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.758-762
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• 2019

Sodium borohydride,$NaBH_4$, has many advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFC). When PEMFC is used for marine use, $NaBH_4$ hydrolysis using seawater is economical. Therefore, in this study, hydrogen was generated by using seawater instead of distilled water in the process of hydrolysis of $NaBH_4$. Properties of $NaBH_4$ hydrolysis reaction using activated carbon supported Co-B/C catalyst were studied. The yield of hydrogen decreased as $NaBH_4$ concentration and NaOH concentration were increased during $NaBH_4$ hydrolysis using sea water. At higher concentrations of $NaBH_4$ and NaOH, byproducts adhered to the surface of the catalyst after hydrolysis reaction using sea water, reduced hydrogen yield compared to distilled water. The activation energy of $NaBH_4$ hydrolysis is 59.3, 74.4 kJ/mol for distilled water and sea water, respectively. In order to increase the hydrogen generation rate in seawater as high as distilled water, the reaction temperature has to be increased by $80^{\circ}C$ or more.

• Korean Journal of Medicinal Crop Science
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• v.27 no.1
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• pp.24-29
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• 2019

Background: Camellia sinensis L.(CS) is a perennial evergreen species of plant whose leaves are used to produce tea. In this plant species, the parts used are the leaves, sub-branch parts are thrown out. Methods and Results: Ethanol extract of sub-branch parts was used for isolation of major compounds by column chromatography. Structures were identified as caffeine (1), (-)-epicatechin (2) and (-)-epicatechin gallate (3) by interpretation of spectroscopic analysis, including $^1H$- and $^{13}C$-NMR. High-performance liquid chromatography (HPLC) method was used to compare the quantitative level of marker compounds in various extraction solvents of sub-branch parts of CS. The content of caffeine, (-)-epicatechin, and (-)-epicatechin gallate in 30% ethanol extract showed higher value with $3.28{\pm}0.57mg/g$, $5.53{\pm}0.88mg/g$, and $1.29{\pm}0.24mg/g$, respectively. Conclusions: These results indicated that not only leaves parts but also sub-branch, could be a good source for the functional material and pharmaceutical industry.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.496-501
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• 2022

In this study, an anode material for lithium secondary batteries was manufactured using petroleum-based residual oil, which is a petroleum refining by-product. Among petroleum-based residual oils, pyrolysis fuel oil (PFO), fluidized catalyst cracking-decant oil (FCC-DO), and vacuum residue (VR) were used as carbon precursors. The physicochemical characteristics of petroleum-based residual oil were confirmed through Matrix-assisted laser desorption/ionization Time-of-Flight (MALDI-TOF) and elemental analysis (EA), and the structural characteristics of anode materials manufactured from residual oil were evaluated using X-ray crystallography (XRD) and Raman spectroscopic techniques. VR was found to contain a wide range of molecular weight distributions and large amounts of impurities compared to PFO and FCC-DO, and PFO and FCC-DO exhibited almost similar physicochemical characteristics. From the XRD analysis results, carbonized PFO and FCC-DO showed similar d₀₀₂ values. However, it was confirmed that FCC-DO had a more developed layered structure than PFO in Lc (Length of a and c axes in the crystal system) and La values. In addition, FCC-DO showed the best cycle characteristics in electrochemical characteristics evaluation. According to the physicochemical and electrochemical results of the petroleum-based residual oil, FCC-DO is a better carbon precursor for a lithium secondary battery than PFO and VR.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.563-575
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• 2020

The purpose of this study is to evaluate the activation characteristics that occur in a linear accelerator for container security inspection. In the computer simulation design, first, the targets consisted of a tungsten (Z=74) single material target and a tungsten (Z=74) and copper (Z=29) composite target. Second, the fan beam collimator was composed of a single material of lead (Z=82) and a composite material of tungsten (Z-74) and lead (Z=82) depending on the material. Final, the concrete in the room where the linear accelerator was located contained magnetite type and impurities. In the research method, first, the optical neutron flux was calculated using the MCNP6 code as a F4 Tally for the linear accelerator and structure. Second, the photoneutron flux calculated from the MCNP6 code was applied to FISPACT-II to evaluate the activation product. Final, the decommissioning evaluation was conducted through the specific activity of the activation product. As a result, first, it was the most common in photoneutron targets, followed by a collimator and a concrete 10 cm deep. Second, activation products were produced as by-products of W-181 in tungsten targets and collimator, and Co-60, Ni-63, Cs-134, Eu-152, Eu-154 nuclides in impurity-containing concrete. Final, it was found that the tungsten target satisfies the permissible concentration for self-disposal after 90 days upon decommissioning. These results could be confirmed that the photoneutron yield and degree of activation at 9 MeV energy were insignificant. However, it is thought that W-181 generated from the tungsten target and collimator of the linear accelerator may affect the exposure when disassembled for repair. Therefore, this study presents basic data on the management of activated parts of a linear accelerator for container security inspection. In addition, When decommissioning the linear accelerator for container security inspection, it is expected that it can be used to prove the standard that permissible concentration of self-disposal.

• Journal of Life Science
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• v.27 no.4
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• pp.390-397
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• 2017

Iron (Fe) is an important micronutrient for the health and growth of plants. Iron is usually provided by fertilizers, and iron-chelate fertilizers are well absorbed by plants. This study presents the plant growth-promoting effects of a new functional iron fertilizer, Fe-chelating crab shell powder (FCSP), which is generated from the chelation of Fe ions with crab shell powder. Iron chelate was derived from spent pickling liquor, which is rich in reductive iron, iron(II) oxide. To analyze the effects of FCSP on plant growth, we treated lettuce with several concentrations of FCSP in both lab- and field-scale experiments. In the lab-scale test, the treatment of 50 ppm of FCSP highly promoted growth and resulted in increases in the size, weight, number and chlorophylls content of leaves of plants compared to the treatment of crab shell powder. Fifty ppm of FCSP also increased the size and weight of leaves up to 2 times compared to the application of chemical fertilizer and/or compost in field conditions. In addition, the FCSP treatment resulted in the highest ion uptake of Fe in lettuce leaves. Moreover, FCSP led to increases in the amounts of Fe, Ca, available phosphorus and organic matter in treated soil, indicating that soil quality was improved. Taken together, our results demonstrate that FCSP promotes lettuce growth via enhancement of Fe availability and improves soil quality. Therefore, FCSP can be utilized as a new functional iron fertilizer.