• Journal of Life Science
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• v.32 no.4
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• pp.298-302
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• 2022

Sulforaphane is a sulfur-containing substance found in large amounts in cruciferous plants and has been reported in several studies to have anticancer effects. Kale is a representative cruciferous plant known as a superfood and is widely used as an ingredient in various dishes. In this study, in order to investigate a cultivation method for increasing kale's content of sulforaphane, kale was treated with geraniol or methyl jasmonate and water stressed during cultivation using a aeroponic culture system in a fully enclosed plant factory. Geraniol or methyl jasmonate were sprayed on the kale's leaf surface once a day for 2 days, and water deprivation stress was conducted for 3 days after 7 days from first treatment day. No difference in growth between control, geraniol, methyl jasmonate treated groups were observed during cultivation. The study results showed that the kale sulforaphane content increased by 60% in the group treated with geraniol compared to the control group and that the group treated with water deprivation stress in addition to geraniol showed a significant increase of 414%. These results show that kale with an increased content of sulforaphane can be grown and that geraniol can be a good research material for increasing the content of functional substances in plants.

• The Korean Journal of Rheology
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• v.11 no.2
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• pp.105-111
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• 1999

Dampers have been used to dissipate energy in mechanical systems. There are several types of dampers such as passive, active, and semi-active damper. Semi-active dampers have higher performance than passive ones and require less power to operate than active ones. Their damping characteristics can be changed properly for varying conditions. In this paper, we investigated the semi-active damper using Magneto-Rheological fluid. Magneto-Rheological fluid, which is one of controllable fluids, changes its damping and rheological characteristics from Newtonian fluid to Bingham fluid as the magnetic field is applied. It has several advantages such as high yield strength, low viscosity, robustness to impurities and wide temperature range of stability. If we designe a semi-active damper by using this material, we can not only design a simply structured damper but also expect rapid response. In this study, we propose several types of semi-active dampers which are designed and manufactured using Magneto-Rheological fluid and some problems encountered during their applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4910-4916
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• 2012

Changes of low concentrated nitrogen-phosphate removal efficiency were investigated in 4 strains of marine bacteria applied to ceramic media. Marine bacteria were isolated and identified from Gwangyang bay. Growth rates and removal efficiencies of $NH_3$-N of 4 strains of marine bacteria applied to ceramic media were increased approximately 3 fold and over 30% than control group, respectively. A. hydrophila and P. diminuta had highest ${NO_3}^-$-N and phosphate removal efficiencies, respectively. This results showed that ceramic media is very nice material for improvement of nitrogen-phosphate removal efficiency and isolated marine bacteria may be useful to control nitrogen-phosphate at low concentration in field.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.3
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• pp.337-349
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• 2000

Genetic Algorithms(GA) together with simulated annealing are often called methods of last resorts since they can be applicable to any kind of problems, particularly those to which no sophisticated procedures are applicable or feasible. The design of structures is primarily the process of selecting a section for each member from those available in the market, resulting in the problem of combinatorial nature. Therefore it is usual for the design space to include astronomical number of designs making the search in the space often impossible. In this work, Genetic Algorithms and some related technique are introduced and applied to the design of steel frameworks. In problems with a small number of design variables, GA found true global optima. GA also found true optima for the continuous variable test problems and proved their applicability to structural optimization. For those problems of real size, however, it appears to be difficult to expect GA to find optimum or even near optimum designs. The use of G bit improvement added to ordinary GA has shown much better results and draws attention for further research.

• Polymer(Korea)
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• v.27 no.4
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• pp.377-384
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• 2003

High impact polystyrene/organically modified layered silicate (HIPS/OLS) nanocomposites by in situ polymerization were synthesized to investigate the effect of clay on the particle size and properties of rubber. In the OLS, the montmorillonite having benzyl group showed best dispersion in polystyrene phase. With the addition of clay, the intercalated peak from XRB was confirmed, but the peak gradually shifted to lower angle as rubber concentration increased. Thus, it is speculated that the organoclay disperses better in rubber phase than in polystyrene phase. The average rubber particle size increased and the particle size distribution widened as the amount of clay increased, which may be caused by the increase of the viscosity ratio of rubber to polystyrene phases and the unstable dispersion. The materials having clay showed improved thermal properties from thermogravimetric analysis. Rheological properties such as complex viscosity and storage modulus increased as the amount of clay increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.3
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• pp.29-33
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• 1982

Saengran, one of the traditional Korean foods, is made from hot taste-removed ginger. It's taste depends upon the recipe and maker's skill however, no standard recipe is established in the literature. In this study, the recipes in the literature were evaluated to find out the best recipe for Saengran. The best method for removing hot taste of ginger was the extraction of ginger in a boiling water for 20 minutes The best formular for Sangran was hot taste removed ginger 100g, sugar 77g, honey 57g, and water 154g. The optimum boiling time was 55 minutes with an electric heater. (100V, 600W)

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.4
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• pp.207-212
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• 2012

A single phase $Mg_3Sb_2$ alloy was synthesized by melting the mixture of Mg and Sb metal powders at 1173 K. The figure of merit of the $Mg_3Sb_2$ prepared by melting method increased with temperature and showed a value of $2.39{\times}10^{-2}$ at 593 K. When the $Mg_3Sb_2$ powders were milled at high speed in a planetary ball mill for 12~48 h, Zintle phase ($Mg_3Sb_2$) was maintained as a main phase, but its crystallinity became deteriorated and elemental Sb phase appeared. Sb phase free $Mg_3Sb_2$ could be obtained by the mechanical alloying of high speed ball milling for 24 h using elemental Mg and Sb powder mixtures.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.495-501
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• 2019

Recently, research has been carried out into the use of carbon fiber reinforced polymer (CFRP), which has good tensile strength and corrosion resistance, as an alternative to rebar. But as of yet, the research into fatigue failure of CFRP is insufficient. In this paper, an analysis was performed of the mechanical behavior and failure patterns of CFRP reinforced concrete beams according to static and cyclic loads, in order to evaluate the safety and validity of CFRP rebar as an alternative material for rebar. The cyclic load ranged from 10 % to 70% of the ultimate load, and was loaded at a speed of 3Hz using a sine wave in the form of a three-point loading method. Through the static load test, the maximum load or stiffness of the beam was found to increase remarkably with the increase of the reinforcement, but the fatigue test showed that the number of repetitions decreased and the amount of deflection increased with the increase of the reinforcement.

• Journal of Korea Water Resources Association
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• v.42 no.6
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• pp.481-491
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• 2009

In this study, a comprehensive field monitoring was conducted to understand habitat conditions of fish species in the upper Geum river. Based on the monitoring data, riverine health conditions such as composition ratio of fish species, richness and dominance indexes, bio-diversity (dominance index, diversity, evenness and richness), and index of biological integrity were assessed, and optimal ecological flowrates were estimated using the habitat suitability indexes established for three fish species Coreoleuciscus splendidus, Zacco platypus and Pseudopungtungia nigra selected as icon species using the physical habitat simulation system (PHABSIM). The total number of species sampled was 20 species, and two sensitive species of C. splendidus (22.4%) and Z. platypus (22.0%) dominated the fish community. The estimated IBI values ranged from 34 to 42 with average being 38 out of 50, rendering the site ecologically fair to good health conditions. An optimal ecological flowrate of 9.0 cms was recommended for the representative fish species at the site.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.195-199
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• 1993

This experiments was designed for development of Fusarium oxysporum strains with enhanced activity of polygalacturonase by means of mutants and protoplasts fusion. Six auxotrophic mutants of F. oxysporum were induced by treatment of MNNG. Protoplasts from mutants were formed from early exoponential mycelium after treatment with driselase(10 mg/ml) using 0.6 M KCl as osmotic stabilizer. Fusion experiments between protoplasts of several auxotrophic mutants were done using polyethyleneglycol 8,000 and $CaCl_2$. The frequency of fusion was $5.0{\times}10^{-3}$ as determined from several experiments. Activity of polygalacturonase was determined by the methods of modified DNS. Consequently, the polygalacturonase activities of mutants and fusant derived F. oxysporum were 1.4 to 3.5 times greater than that of the parental strain, and mutant Fx-2 seemed to be the best strain. Thus, the method we used seemed to be favorable for the improvement of strains.