• Journal of Korea Foundry Society
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• v.29 no.3
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• pp.120-127
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• 2009

The characterestics of high Si-high Mo ductile cast iron, high Si-high Mo C.V. cast iron and Ni-resist cast iron were compared and evaluated. The nodule count of the last one was lower and the nodularity was higher than those for the first one, respectively. The first two had ferritic matrices with small amounts of molybdenum carbides. The first one had the highest tensile strength and the last one the lowest elongation. This had the highest high temperature strength and that of the second one was greatly increased from the room temperature strength. The volumes of the first two were decreased during cooling and that of the last one changed little. The thermal expansion coefficient of the last one was the highest and the first one the lowest. During high temperature oxidation, even though the volume of the first one was increased, the weight was decreased and the volume and weight of the second one were increased. The change of the increased weight of the last one was more than that of thickness.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1400-1402
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• 2010

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1864-1866
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• 2013

• Journal of applied mathematics & informatics
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• v.36 no.1_2
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• pp.93-105
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• 2018

There are many metric functions in the plane. In this paper we are to classify the metric functions on the plane using two ways such as using sum of distances between some points when start point and end point is fixed, and using area of transferred triangle consisted of distances between 3 points.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.669-670
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• 2004

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1723-1725
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• 1999

This paper is the study for piezoelectric properties of PMN-PT-PZ composition for high power piezoelectric device. It needs the properties such as high mechanical quality factor(Qm), high electromechanical coupling coefficient(kp) and high dielectric strain constant$(d_31)$, and the stable electromechanical properties under high vibration level. For acquiring this results, the value of x is changed in 0.1Pb$(Mn_{1/3}Nb_{2/3})O_3$+(0.9-x)$PbZrO_3+xPbTiO_3$ composition to find MPB(morphotropic phase boundary), and the piezoelectric constants is measured by resonance-antiresonance frequency method, based on IRE Standard. Also, it is measured as a function of the amount of additive, $Nb_2O_5$. When the composition is applied to high power device, the electromechanical properties is measured by laser vibrometer to confirm the reliablity under high vibration level. From these results, PMN-PT-PZ composition is shown excellent properties and capacity of application to high power device.

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.295-300
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• 2012

SiC-based ceramic matrix composites show many advantages over their monolithic ceramic counterparts, which makes them potential candidates for applications in various fields. Depending strongly on the chemical composition and microstructure of the fiber reinforcement, matrix as well as the fiber/matrix interphase in the material, the properties of ceramic matrix composites(CMCs) are highly tailorable. In this paper, the latest progresses in the interphase design, matrix modification and fiber reinforcement decoration of CMCs are reviewed, their effects on the properties of the CMCs are introduced.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.3
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• pp.267-272
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• 2015

The purpose of this study was to examine the antiobesity effects of lactic acid bacteria-fermented Dioscoreae Rhizoma powder (LDR) in Sprague-Dawley rats with high-fat diet (HFD)-induced obesity. Rats were divided into 5 groups: normal diet group, control (high fat diet-vehicle) group, 0.4 g/kg LDR (high fat diet + 0.4 g/kg lactic acid bacteria-fermented Dioscoreae Rhizoma powder) group, 1 g/kg LDR (high fat diet + lactic acid bacteria-fermented Dioscoreae Rhizoma powder) group, 2.5g/kg LDR (high fat diet + lactic acid bacteria-fermented Dioscoreae Rhizoma powder) group. Our results indicate that LDR administration has effects on decreasing of body weight, fat weight, blood parameters and adipocyte size in the obesity animals. In addition, verified that fat degeneration and ballooning degeneration were alleviated in the experimental group fed on a high fat diet combined with LDR groups. These results indicate that lactic acid bacteria-fermented Dioscoreae Rhizoma powder may reduce elevating body weight and lipid accumulation in rat fed a high fat diet, suggesting its usefulness as a functional food for reducing body fat and obesity.

• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.205-210
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• 2004

A weighted self-tuning robust regression estimator (WSTE) has the high breakdown point for estimating regression parameters such as other well known high breakdown estimators. In this paper, we propose to obtain standard quantities like confidence intervals, and it is found to be superior to the other high breakdown regression estimators when a sample is contaminated

• Advances in concrete construction
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• v.1 no.2
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• pp.151-162
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• 2013

The performance characteristics of high-strength and high-performance concrete are discussed in this review. Recent developments in the field of high-performance concrete marked a giant step forward in high-tech construction materials with enhanced durability, high compressive strength and high modulus of elasticity particularly for industrial applications. There is a growing awareness that specifications requiring high compressive strength make sense only when there are specific strength design advantages. HPC today employs blended cements that include silica fume, fly ash and ground granulated blast-furnace slag. In typical formulations, these cementitious materials can exceed 25% of the total cement by weight. Silica fume contributes to strength and durability; and fly ash and slag cement to better finish, decreased permeability, and increased resistance to chemical attack. The influences of various mineral admixtures such as fly ash, silica fume, micro silica, slag etc. on the performance of high-strength concrete are discussed.