• Journal of Power Electronics
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• v.4 no.3
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• pp.188-196
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• 2004

The dielectric barrier discharge is recognized as one of the efficient methods of ultraviolet light generation and ozone production. As well, it is widely utilized for gaseous wastes neutralization and other technological processes in industry. This electrochemical reaction is electrically equivalent to a nonlinear capacitive load that represents some difficulties for designing the power supply. Therefore, a conventional power supply is designed for a drastically simplified model of the load and generally is not optimal. This paper presents a fast simulation approach for the nonlinear capacitive model representation of the dielectric barrier discharge load lamp. The main idea of the proposed method is to use analytical solutions of the differential state equations for the load and find the unknown initial conditions for the steady state by an optimization method. The derived expressions for the analytical solutions are rather complicated, however they greatly reduce the calculation time, which make sense when a deeper analysis is performed. This paper introduces the proposed simulation method and gives some examples of its application such as estimation of the load equivalent parameters and load matching conditions.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.30 no.1
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• pp.29-42
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• 2017

Objectives : Atopic dermatitis accompanies with severe pruritus and collapse of skin barrier, inflammation. Maifanite could be used as an ointment for skin disease. However, there have been few studies about maifanite uses for atopic dermatitis. We report the anti-inflammatory and promoting skin recovery effects of ionized maifanite on damaged skin barrier with experimentally elicited atopic dermatitis. Methods : Nc/Nga mice were divided into 3 groups: control group(CON), atopic dermatitis elicited group(AE group), ionized maifanite treated group after atopic dermatitis elicitation(MT group). After 5% SDS was applied D. pteronyssinus crude extract also applied for 3 weeks to elicit atopic dermatitis-like skin disease. MT group was treated for 3 weeks with ionized maifanite. Ionized maifanite was applied once a day and voluntarily administrated. AE group and control group were treated with normal saline in the same way. Results : In MT group, skin lesions like eczema were more improved than AE group. p-ERK1/2 positive reaction was reduced in MT group. MMP-9 and substance P positive reaction at dermal papillae was also reduced in MT group. With skin angiogram, capillary vessel decreased in MT group. Also, IL-4 positive reaction cell and STAT-6 positive reaction cell reduced more in MT group than in AE group. $NF-{\kappa}B$ p65 positive reaction cell and iNOS positive reaction cell also declined more in MT group than in AE group. Conclusions : It is supposed that ionized maifanite has anti-inflammatory effects on NC/Nga mice's atopic dermatitis with suppressing IL-4 production and Th2 cell differentiation, and controlling $NF-{\kappa}B$ activation.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.505-511
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• 1998

The silicide formation mechanisms of Co/Hf and Co/Nb bilayer on (100) Si have been investigated. We ob-served that crystallographic orientationso f the 500$^{\circ}C$ formed cobalt silcides were different each other with the varying intermediate layers. Epitaxial and non-epitaxial CoSi2 formed simultaneously in Co/Hf/(100Si. While only non-epitaxial CoSi2 formed in Co/Nb/(100) Si. The reason why the crystallographic orientation of CpSi2 is different for those two systems seemed to be relate to the formation and decomposition of stable reaction barriers at high temperature. The stable reaction barrier formed at high temperature could control the uniform diffusion of Co atoms which enables epitaxial growth of CoSi2.

• Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.9-14
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• 2012

The objectives of this research were to improve the film-forming properties of Channel Catfish Ictalurus punctatus skin gelatin (CSG) by cross-linking with transglutaminase (TG), determine and optimize the TG reaction time, and characterize the mechanical and barrier properties of CSG edible film. Cross-linking of CSG was performed by TG for 0, 10, 20, 30, and 40 min at $50^{\circ}C$, and the reaction was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The color and mechanical and barrier properties of edible films fabricated with CSG cross-linked with TG were characterized. Gelatin yields from the extraction ranged from 18.2% to 23.3%. SDS-PAGE exhibited dark bands at 120 and 250 kDa, indicating successful TG-mediated cross-linking. The color of CSG film was not affected by TG cross-linking. The tensile strength of CSG films cross-linked with TG decreased from 42.59 to 21.73 MPa and the percent elongation increased from 42.92% to 76.96% as reaction times increased from 0 to 40 min. There was no significant difference in water vapor permeability of CSG films.

• Journal of Environmental Science International
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• v.30 no.5
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• pp.399-406
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• 2021

The dissolution of ionized gas in dielectric barrier plasma, similar to the principle of ozone generation, is a major performance-affecting factor. In this study, the plasma gas dissolving performance of a gas mixing-circulation plasma process was evaluated using an experimental design methodology. The plasma reaction is a function of four parameters [electric current (X₁), gas flow rate (X₂), liquid flow rate (X₃) and reaction time (X₄)] modeled by the Box-Behnken design. RNO (N, N-Dimethyl-4-nitrosoaniline), an indictor of OH radical formation, was evaluated using a quadratic response surface model. The model prediction equation derived for RNO degradation was shown as a second-order polynomial. By pooling the terms with poor explanatory power as error terms and performing ANOVA, results showed high significance, with an adjusted R² value of 0.9386; this indicate that the model adequately satisfies the polynomial fit. For the RNO degradation, the measured value and the predicted values by the model equation agreed relatively well. The optimum current, gas flow rate, liquid flow rate and reaction time were obtained for the highest desirability for RNO degradation at 0.21 A, 2.65 L/min, 0.75 L/min and 6.5 min, respectively.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.57-66
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• 2010

This study is described in heavy metal pollution by the stony mountain development using field case. The heavy metal pollution is investigated for nearby area (soil and stream) of the developed stony mountain, and then the countermeasure using contamination analysis is suggested. The investigation result indicated that contamination of Sammak stream caused by the stone dust and leachate at the stony mountain development. Therefore, the heavy metal pollution is evaluated by using Pollution Index(PI). The evaluation results confirmed that the contaminated groundwater was the leading cause of the contamination in Sammak stream and nearby soil. Therefore, the Permeable Reaction Barrier(PRB), which has a environmentally-friendly reactant, should be applied to control a heavy metal of groundwater, and it will be a reasonable countermeasure.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.554-558
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• 2017

In order to achieve a hydrophobic surface of silica, we reacted silica nanoparticles with hexamethyldisilazane (HMDS) under various reaction conditions. Modification of the surface of silica with organic materials was confirmed by the thermogravity and elemental analysis. The modified silica displayed nearly the same morphology as to the pristine silica. The reaction of 20 g of HMDS with 1 g of silica in decalin at $200^{\circ}C$ for 6 hours was found to be the optimum reaction condition in terms of the dispersity in toluene and the surface roughness of composite films. Oxygen permeation studies of the composite film demonstrated that the modified silica enhanced a gas barrier performance.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.4
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• pp.243-250
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• 2019

This objective of this study was to investigate the degradation characteristics of phenol, a refractory substance, by using a submerged dielectric barrier discharge (DBD) plasma reactor. To indirectly determine the concentration of active species produced in the DBD plasma, the dissolved ozone was measured. To investigate the phenol degradation characteristics, the phenol and chemical oxygen demand (COD) concentrations were evaluated based on pH and the discharge power. The dissolved ozone was measured based on the air flow rate and power discharged. The highest dissolved ozone concentration was recorded when the injected air flow rate was 5 L/min. At a discharge power of 40W as compared to 70W, the dissolved ozone was approximately 2.7 - 6.5 times higher. In regards to phenol degradation, the final degradation rate was highest at about 74.06%, when the initial pH was 10. At a discharged power of 40W, the rate of phenol decomposition was observed to be approximately 1.25 times higher compared to when the discharged power was 70W. It was established that the phenol degradation reaction was a primary reaction, and when the discharge power was 40W as opposed to 70W, the reaction rate constant(k) was approximately 1.72 times higher.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.295-302
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• 2008

This paper examines the design and the performance of a PMA-RSM(permanent-magnet assisted reluctance synchronous motor) for washing machine. A FEM(finite element method) is used to analyze performance and maximum torque characteristic of the proposed PMA-RSM. The designed motor is a combination of salient poles, which is making reluctance torque, and permanent magnet which are located on the air-gap of rotor to get a enough torque during low speed resign. Typical flux barrier type reluctance synchronous motor and the effects of adding magnet into the flux barrier of the rotor of a PMA-RSM are compared and examined. Also the maximum torque point of the reluctance torque by reluctance and reaction torque by magnetic alignment torque, which is in barrier, of the proposed PMS-RSM are derived through simulation. Using this results, the characteristics analysis of a performance, an average torque and a torque ripple of flux barrier RSM and the proposed PMA-RSM are performed through FEM under the saturation effect respectively.

• Journal of the Korean GEO-environmental Society
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• v.16 no.5
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• pp.5-11
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• 2015

The double sheeted permeable reactive barrier containing two different reactive materials can be applied to remediate the groundwater contaminated by nutrients and heavy metals. In this study, in order to evaluate the removal efficiency of contaminants including ammonium, cadmium and phosphate by double layered permeable reactive barrier containing zeolite and steelmaking slag, column tests were performed. In addition, nonequilibrium reaction in column tests was analyzed by two-site nonequilibrium advection-dispersion model. Column test results showed that zeolite is effective for removal of ammonium, while steelmaking slag is effective for removal of phosphate and cadmium. The sequential reaction of zeolite and steelmaking slag gave the better removal efficiency for ammonium.