• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.59-64
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• 2013

The present study is to evaluate physical and mechanical properties of porous concrete having non cement that mainly causes carbon emission. This study aims to explore eco-friendly concrete technology capable of reducing the amount of carbon emission due to the use of normal cement by substituting it with non cement porous concrete to which alkali-activator and blast-furnace slag powder are impregnated. As experimental variables, 5 %, 6 %, 7 %, 8 %, 9 % and 10 % of alkali-activator were substituted as binders and applied. Testing evaluated in this study were pH value, void ratio, compressive strength and residual compressive strength shown after being immersed in $H_2SO_4$ solution and $Na_2SO_4$ solution. The test results were compared with those tested with the use of porous concrete to which 400 $kg/m^3$ of unit cement amount was applied as binder. In consequence, it was concluded that; as for pH value, it was decreased than was the case in which cement was used, but increased with the more the use of alkali activator; as for void ratio and compressive strength, the mix proportion in which 9 % and 10 % of alkali activator were applied in terms of substitution ratio showed the result similar to the mixture in which 400 $kg/m^3$ of unit cement ratio was applied; and, as for residual compressive strength in the case of being immersed in $H_2SO_4$ solution and $Na_2SO_4$ solution, the compressive strength was increased, thus leading to improved chemical resistance.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.551-559
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• 1997

The stability of liquid membrane in the extraction process was investigated through the extraction of the Zn component by using W/O/W emulsion type liquid surfactant membrane which was $D_2EHPA-Kerosene-Span$ $80-H_2SO_4$ system. The highest stability for liquid membrane through the Zn extraction process was obtained under the following conditions. That conditions were that span 80 concentration, as surfactant, of 2~3 vol.%;$D_2EHPA$ concentration, as extractant, of 5~7 vol.%;paraffin oil concentration, as membrane strengthening agent, of 10 vol.%;emulsion volume ratio to the external aqueous phase volume of 0.1, and internal aqueous phase volume ratio to the organic phase volume of 1.0.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.83-91
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• 2017

This study made jelly by adding Sansuyu (Corni Fructus) puree and examined the types and contents of gelling agents as well as the physicochemical characteristics of jelly depending on heating time. Water content of Sansuyu puree was 89.39%, pH was 2.92, sugar content was $10.28^{\circ}Brix$, and total polyphenol content was 1,791.71 mg GAE/100 g. As the added amount of Sansuyu puree increased, pH decreased slightly from 3.04 to 2.97, and yield stress decreased greatly. As heating time increased, red color was unstable and changed to yellow. When heated more than 5 min, jelly was not formed. The level of preference for jelly consisting of 10% Sansuyu puree, 1.5% agar, and 1.0% carrageenan was the highest at 5.15. Using pulp of Sansuyu, it will be possible to make jelly consisting of various bioactive substances.

• Food Science of Animal Resources
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• v.24 no.4
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• pp.405-410
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• 2004

This study was performed to investigate the antioxidative activity of soybean products extracts using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and thiobarbituric acid (TBA) method for application of animal products. All three extracts (natto, soybean paste, soybean milk extract) were found to have an ability to donate hydrogen to DPPH. Especially, natto and soybean paste extract were more effective than that of soybean milk on the antioxidative activities. Natto and soybean paste extract were stronger than butylhydroxy toluene (BHT), butyl hydroxyl anisole (BHA) (5${\times}$10$^{-4}$ M) and ascorbic acid (5.7${\times}$10$^{-3}$ M) previously well known as antioxidants. These extracts also showed a synergistic effect. TBA values of natto (45.8％) and soybean paste extract (45.2％) were stronger than that of soybean milk extract (33.6％). These results suggest that soybean product extracts have antioxidative activities and synergistic effects.

• The Journal of the Korea Contents Association
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• v.12 no.7
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• pp.194-202
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• 2012

This study conducted empirical research from the behavioral perspective with a survey to residents in order to grope for directions to develop a local council. The results gained from the research can be summed up as below: First, according to the result of evaluation on the essential roles (resident representative, checks, and legislation functions) of the council, the residents could not see any improvement in general. Regarding parliamentary activities and administrative changes, they also hardly felt any great changes. Second, according to the result of detailed evaluation on the council activities, the residents regard the collection of residents' opinions or the division exclusively in charge of collecting opinions to be very important. Third, in the developmental evaluation on the local council, they consider it is very crucial to induce outside specialists to secure expertise and establish the system to activate residents' participation. Above results imply that for the development of local councils, it is essential for the councils to play their roles responsibly as well as positively through communication and negotiation with the residents. It is thought that the research results will contribute to explaining the directions to develop local councils both practically and theoretically.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.50-55
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• 2000

Soluble methyl-hesperidin (MH) powder was prepared from crude MH, and was investigated on the stabilization to sunlight of natural coloring matter. Soluble MH powder was added to riboflavin, bixin, and paprika oleoresin solutions at concentration of 0.1 or 0.2%(w/w), and the absorbance of respective solutions was analyzed by spectrophotometer after exposing to sunlight for $10{\sim}24$ hr. While coloring matter solutions without MH was faded completely with lapse of time, addition of MH retarded to fade natural coloring matters. According as amount of MH added increased, MH showed more excellent stabilizing effect on the coloring matters. Especially, vitamin C with soluble MH showed remarkable synergistic effect in paprika oleoresin solution during the exposure to sunlight for 8 hr. Consequently, it was found that MH plays a role as excellent stabilizer of natural coloring matters to ultraviolet of sunlight.

• Applied Biological Chemistry
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• v.49 no.3
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• pp.254-258
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• 2006

Vitellogenin has been known as a potent biomarker protein for the estrogenic activity in fish exposed to endocrine disruptors. In this study, a piezoelectric immunosensor making use of an anticarp vitellogenin antibody and an AT-cut quartz crystal microbalance as the biological component and transducer was prepared, followed by its application to the analysis of carp vitellogenin as follows. Antibody immobilization was conducted by chemisorption of a thiolated antibody with a heterobifunctional thiolation cross-linker, sulfosuccinimidyl 6-[3-(2-pyridyldithio)propionamido]hexanoate. The reaction buffer for the immunosensor system was optimized as 0.1 M sodium phosphate (pH 7.4). Concentration-dependent sensor responses were obtained in the vitellogenin concentrations ranging from 0.4864 to 486.4000 nM, with a linear correlation between vitellogenin concentration and frequency shift in double-logarithmic scale. The limit of detection of the immunosensor for carp vitellogenin was presumed as 0.4864 nM.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.15-19
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• 2021

In this study, we studied a facile method for the synthesis of stable and nearly spherical gold nanoparticles using a tyrosine-rich peptide, Tyr-Tyr-Gly-Tyr-Tyr (YYGYY), as both the reducing and capping agent. The peptide coated spherical and polycrystalline gold nanoparticles with diameters from 3 to 15 nm were successfully synthesized by varying the concentration of the peptide and metal precursor under UV irradiation. The nanoparticles were then characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). Furthermore, the catalytic activity of gold nanoparticles was confirmed by the reduction of 4-nitrophenol to 4-aminophenol, in which the catalytic reaction rate constant was 7.3 × 10-3 s-1.

• Journal of the Korean Geotechnical Society
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• v.30 no.1
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• pp.65-74
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• 2014

Cemented soils have been widely used in road and dam construction, and recently ground improvement of soft soils. The strength of such cemented soils can be tested by using cored sample or laboratory-prepared specimen through unconfined compression or triaxial tests. It takes time to core a sample or prepare a testing specimen in the laboratory. In a certain situation, it is necessary to determine the in-situ strength of cemented soils very quickly and on time. In this study, the relation between unconfined compressive strength and shear wave velocity was investigated for predicting the in-situ strength of cemented soils. A small cemented specimen with 5 cm in diameter and 10 cm in height was prepared by Nakdong river sand and ordinary Portland cement. Its cement ratios were 4, 8, 12, and 16% and air cured for 7, 14, and 28 days. For recycling of resources, a blast furnace slag was also used with sodium hydroxide as an alkaline activator. The shear wave velocity for cemented soils was measured and then unconfined compressive strength test was carried out. As a cement ratio increased, the shear wave velocity and unconfined compressive strength increased due to increased density and denser structure. The relation between unconfined compressive strength and shear wave velocity increased nonlinearly for cemented soils with less than 16% of cement ratio.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.199-205
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• 2018

A geopolymer was produced from coal ash generated from an integrated gasification combined cycle (IGCC) plant and its water resistance was evaluated. For this purpose, the geopolymer specimens were immersed in water for 30 days to measure changes in microstructure and alkalinity of the immersion liquid. Particularly, the experiment was carried out with foaming status of the geopolymers and parameters of room temperature aging condition, and immersion time. The foamed geopolymer containing 0.1 wt% Si-sludge had pores with a diameter of 1 to 3 mm and exhibited excellent foamability. Also, the calcium-silicate-hydrate crystal phase appeared in the foamed geopolymer. In the geopolymer immersion experiment, the pH of the immersion liquid increased with time, because the un-reacted alkali activator remained was dissolved in the immersion liquid. From the pH change of the immersion liquid, it was found that geopolymer reaction in the foamed specimen was completed faster than the non-foamed specimen. Through this study, it was possible to successfully produce foamed and non-foamed geopolymers recycled from IGCC coal ash. Also the necessary data for the safe application of IGCC coal ash-based geopolymers to areas where water resistance is needed were established; for example, the process conditions for room temperature aging time, effect of foaming status, immersion time and so on.