• Advances in materials Research
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• v.5 no.1
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• pp.55-66
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• 2016

This paper describes a study on the effects of $Mg_2Si_{(p)}$ addition on the microstructure, porosity, and mechanical properties namely hardness and tensile properties of AA332 composite. Each composite respectively contains 5, 10, 15, and 20 wt% reinforcement particles developed by a stir-casting. The molten composite was stirred at 600 rpm and melted at $900^{\circ}C{\pm}5^{\circ}C$. The $Mg_2Si$ particles were wrapped in an aluminum foil to keep them from burning when melting. The findings revealed that the microstructure of $Mg_2Si_{(p)}/AA332$ consists of ${\alpha}$-Al, binary eutectic ($Al+Mg_2Si$), $Mg_2Si$ particles, and intermetallic compound. The intermetallic compound was identified as Fe-rich and Cu-rich, formed as polygonal or blocky, Chinese script, needle-like, and polyhendrons or "skeleton like". The porosity of $Mg_2Si_{(p)}/AA332$ composite increased from 8-10% and the density decreased from 9-12% from as-cast. Mechanical properties such as hardness increased for over 42% from as-cast and the highest UTS, elongation, and maximum Q.I were achieved in the sample of 10% $Mg_2Si$. The study concludes that combined with AA332, the amount of 10 wt% of$Mg_2Si$ is a suitable reinforcement quantity with the combination ofAA332.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.106-112
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• 2010

In order to compete with other flat display devices such as Liquid Crystal Displays (LCDs) and organic light emitting diodes (OLEDs), Plasma Display Panels (PDPs) require to have high performances like high image quality, low power consumption and high speed driving. In this paper, Fe doped MgO protective layer was introduced for higher performance. Both the surface characteristics of the deposited thin films and the electro-optical properties of 4 inch test panels were investigated. It has been demonstrated experimentally that ac PDP with Fe doped MgO protective layer has lower discharge voltage than that of undoped MgO film, which corresponds to measured secondary electron emission coefficients. The crystallinity and surface roughness of thin films were determined by XRD patterns and AFM images. In addition, ac PDP with Fe doped MgO protective layer has improved address discharge time lag for high speed driving.

• Journal of Fisheries and Marine Sciences Education
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• v.15 no.2
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• pp.176-183
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• 2003

Recently, with the tendency of lightening, high-strength and high-speed in the marine industries such as marine structures, ships and propellers, it is rapidly enlarged the use of the aluminium alloy. Therefore, there occurs much interest in the study on corrosion characteristics of aluminium alloy. This paper was studied on the corrosion characteristics of Al-Mg alloy propeller used for a coasting vessel. Under the various pH of marine environment, the corrosion test of Al-Mg alloy was carried out. And thus polarization resistance, corrosion potential, and current density behavior of Al-Mg alloy and galvanic corrosion behavior of Al-brass and Al-Mg alloy coupled Al 5086 and SS 400 for hull were investigated. The main results are as following: 1. The corrosion potential of Al-brass propeller is more nobel than materials for hull, but that of Al-Mg alloy propeller is low or similar to materials for hull. Therefore, the galvanic corrosion of hull due to Al-Mg propeller don't occur. 2. The polarization resistance of Al-Mg alloy in sea water of pH 4 is highest, and corrosion current density of Al-Mg propeller is the most controlled. 3. As pH value decreases, potential showed Evans polarization diagram approaches cathodic potential. The corrosion current density of Al-Mg alloy is controlled to anodic reaction rate, therefore, the corrosion reaction of Al-Mg alloy is anodic control.

• Journal of Korean Association for Spatial Structures
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• v.6 no.4 s.22
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• pp.73-80
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• 2006

It is an object of the present paper to investigate a electrochemical properties of Mg-based sacrificial anodes and the effect of calcium added from calcium chloride into magnesium on the melt protection during the melting. Electrochemical data will be correlated with processing control variables, and the microstructural change by the addition of CaCl2. Small addition of calcium into magnesium from CaCl2 imparts beneficial effect in electrochemical properties of Mg alloys, primarily, through microstructural modifications. In addition, the protection effect of the melts surface of Ca with low melting point modification is obtained by adding Ca not more than 0.6%.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.40-47
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• 2010

In this paper, we propose a probability method to determine minimum capacity of energy storage system(ESS) for Micro Grid(MG). Because of high capital cost of ESS, it's very important to determine optimal capacity of ESS and for stable operation of MG and we should determine minimum capacity of ESS. The proposed method has abilities to consider forced outage rate of generators and intermittent of non-dispatchable generators and minimum capacity make MG keep energy balancing by oneself.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.626-632
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• 2011

Phoxim, which is one of veterinary drugs, is a well-known antiparasitic agent in wide use. In this paper, phoxim was extracted from cattle and pig tissue using solid-phase extraction (SPE) employing a silica cartridge with acetonitrile. Liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) for the analysis of phoxim from animal tissue was presented. Phoxim was detected on a $C_{18}$ column ($2.1{\times}100\;mm$, $3.5\;{\mu}m$) using a mobile phase of 0.1% formic acid in water and acetonitrile. A linear correlation observed in the calibration curves for cattle (0.0048~2.0 mg/kg) and pig (0.0055~2.0 mg/kg) showed above $r^2$=0.995. Accuracy measured at concentrations ranging from 0.0048 to 0.2 mg/kg was the range of 68.2~106.9%. Limit of detection (LOD) and limit of quantitation (LOQ) were the range of 0.0014~0.0017 mg/kg and 0.0048~0.0055 mg/kg, respectively. The precision (RSD%) was below 11.2%.

• Korean Journal of Organic Agriculture
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• v.30 no.1
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• pp.89-101
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• 2022

This study was conducted to examine decay incidence of citrus fruit treated with antifungal patches during short-term storage using 10 kg paper boxes at room temperature. It was investigated for 15 days in 'Iwasaki' and for 30 days in 'Miyagawa' treated with 200 mg/kg and 500 mg/kg patches of hexanal, carvacrol, and cinnamaldehyde alone or mixed. When it was treated with 200 mg/kg in 'Iwasaki, The decay rate of fruit was at 1.0% in carvacrol alone. In 'Miyagawa', The decay rate of fruit showed lower at cinnamaldehyde and hexanal+cinnamaldehyde mixture of 500 mg/kg than others. And also hexanal+cinnamaldehyde mixture of 200 mg/kg was twice lower than others. In conclusion, the mixed antifungal patches was more effective in reducing citrus fruit decay in citrus fruits than alone at room temperature.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.421-424
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• 2008

Edible red algae paper coated with green tea ext Tact was prepared and determined the microbial growth and quality change of kimbab wrapped with the paper during storage. The paper coated with green tea extract had the antimicrobial activity against Listeria monocytogenes and Escherichia coli. After 12 hr of storage of kimbab, packaging with the paper coated with green tea extract decreased populations of total aerobic bacteria by 1 log cycle. Kimbab wrapped with the red algae paper coated with green tea extract had 5.5 mg malondialdehyde (MDA)/kg after 12 hr, in contrast to the control of 7.4 mg MDA/kg. Kimbab with red algae paper with green tea extract was better than the control in terms of sensory qualities. These results clearly indicate that kimbab can be packaged with red algae paper coated with green tea extract, resulting in extending its shelf life.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.141-149
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• 2009

The oil pan is an important factor for the noise behavior of the engine system. In this paper a new Magnesium oil pan was designed and analyzed to replace the current Aluminium oil pan. Dynamic stiffness and sound pressure level of the newly designed Mg oil pan were compared with the AI oil pan using the finite element method. NVH characteristics of the Mg oil pan is slightly insufficient when we changed the material of the oil pan from Al to Mg without modifying the design. Some design modifications of the Mg oil pan resulted in equal or superior characteristics compared to the Al oil pan. New ribs were added to stiffen the structure of the Mg oil pan. Thickness of thin plate area was increased to reduce the radiated noise. Through the changes of shape, higher dynamic stiffness than the current Al oil pan were achieved. Results of frequency response analysis show that we can reduce the sound pressure level of the oil pan if we increase the thickness of the thin plate area. It is shown that the new Mg oil pan could reduce the weight of the engine system and improve NVH quality of an automobile.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.307-311
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• 2013

Direct Air Capture (DAC) technology using reusable energy is a plausible process to capture $CO_2$ from non-point sources. In this paper, adsorption and desorption were repeatedly tested using low concentration $CO_2$. Three types of adsorbents were examined in cyclic $CO_2$ adsorption and thermal regeneration. Adsorption capacities of zeolite 5A, zeolite 13X and activated carbon were 21 mg/g, 12 mg/g and 6 mg/g, respectively. Zeolite 5A shows the highest adsorption capacities after cyclic thermal regeneration.