• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.53-56
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• 2003

In this paper we investigated electrical properties for epoxy resin with improved mechanical property, elastomer epoxy. Investigated electrical properties are permittivity, tan $\delta$ and breakdown voltage strength(BDV). Permittivity and tan $\delta$ have dependancy on additive Quantity in general purpose epoxy resin. In particularly, those have very high values at low frequency and high temperature according to increasing component of elastomer. In case of BDV test, those materials have only a little difference due to increasing elastomer components. But in case of high quantities of elastomer, BDV has a difference. These results are represented that elastomer epoxy resin despite superior mechanical property needs many carefully thought as application electrical insulation.

• Journal of Mechanical Science and Technology
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• v.14 no.6
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• pp.690-698
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• 2000

The laminar boundary layer flow and heat transfer of anisotropic fluids in the vicinity of a wedge have been examined with constant surface temperature. The similarity variables found by Falkner and Skan are employed to reduce the stream wise-dependence in the coupled nonlinear boundary layer equations. The numerical solutions are presented using the fourth-order Runge - Kutta method and the distribution of velocity, micro-rotation, shear and couple stresses and temperature across the boundary layer are plotted. These results are also compared with the corresponding flow problems for Newtonian fluid over wedges. It is found that for a constant wedge angle, the skin friction coefficient is lower for micropolar fluid, as compared to Newtonian fluid. For the case of the constant material parameter K, however, the magnitude of velocity for anisotropic fluid is greater than that of Newtonian fluid. The numerical results also show that for a constant wedge angle with a given Prandtl number, Pr = I, the effect of increasing values of K results in increasing thermal boundary layer thickness for anisotropic fluid, as compared with Newtonian fluid. For the case of the constant material parameter K, however, the heat transfer rate for anisotropic fluid is lower than that of Newtonian fluid.

• Journal of the Korean Society of Clothing and Textiles
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• v.10 no.2
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• pp.69-77
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• 1986

A study was made of the effect of zeolite in detergent on the removal of soils correlating the characteristics of soil components. The detergency of natural soil was increased with increasing zeolite concentration but the effect on detergency was inferior to STPP. In case of carbon black based artificial soils. The detergency of soil containning non-polar oily soil was not improved by zeolite but the detergancy was increased with increasing zeolite concentration when polar oily soils were added to the soil. In case of iron black based artificial soils. Though the detergency was better than that of carbon black based soils, the detergency was not improved by zeolite regardless of oily soil components. The effect of zeolite on removal of oily soil was studied with tripalmitin and palmitic acid as model soils. The effect of zeolite and STPP on the removal of tripalmitin, the detergency was increased with in creasing STPP concentration but not zeolite.

• Textile Coloration and Finishing
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• v.31 no.4
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• pp.288-297
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• 2019

The specimens were heat treated at 180℃, 190℃, 200℃, 210℃ and 220℃ to observe the change of the physical properties of the double raschel pile fabric. The density, tensile strength, weight, elongation, dyeing characteristics, fabric surface morphology and cross sectional shape were observed by heat treatment temperature. Compared with untreated samples, weight, density and tensile strength were increased with increasing heat treatment temperature. No increase was observed at 220℃. In the case of elongation, it increased to 190℃ but thereafter it could not be observed. In the case of uprightness of brushed hair, it was observed that the gap between the yarns was narrowed and the density was increased and the straightness of the yarn and pile yarn was improved by widening the heat treatment temperature. As a result, it was observed that the uprightness was remarkably improved and the bulky properties was increased. It was also observed that the increase of the dyeability was observed with increasing the heat treatment temperature.

• Journal of Information Technology Services
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• v.15 no.2
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• pp.35-49
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• 2016

With the gradual development of IT technology, voice phishing victims are increasing in number. In the past when only voice phone calls were made, personal information or financial information were stolen mainly by a direct phone call, but recently, as smart phones are widely in use, it is evolving into a way such as smishing that leads an access to a site with malicious codes spreading out. Since it is easy to run away after committing a crime, and trace are rarely left in case of voice phishing, it is difficult to find out criminal. In addition, it is most likely that a victim be would be exposed to further damage from another voice phishing. Its technique is growing in kinds and turning more intelligent day by day; Therefore, its victims are increasing in number. Previous researches mainly focused the area of legal studies while the factors exposed to voice phishing have not been made. Therefore, this study has analyzed the motifs in which voice phishing is done to draw out its outcomes as follows. First, a victim comes to trust the criminal by the factors of favorability, rare message, and mutuality. Second, the more sophisticated the technique of a criminal, the more likely a victim is exposed to voice phishing.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.30-40
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• 2013

In this study the method based on flux linkage in cell was introduced in calculation of eddy currents by cell method. According to this method eddy current distribution and the loss can be evaluated and since the shielding effectiveness by flux cancelation of eddy current can be analyzed, this method is applicable to design of conductive shield. And also the formula of shielding factor were so deduced as to be applicable to finite-width infinite-length shielding sheets and infinite-length underground cable shield. These formula are adaptable to magnetic materials as well as conductive materials. As the results of calculation in model shields are follows. In case of finite-width infinite-length shielding sheet, shielding effectiveness increases with increasing of conductivity. In case of infinite-length underground cable shield, the effectiveness become higher with increasing of permeability. Especially the effectiveness is very high in materials with both high conductivity and permeability in underground cable shield.

• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.203-213
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• 2015

Recently, online grocery shopping has been increasing with the development of internet, mobile, and IT technology due to the proportion of consumers changes like increasing single households and double-income couples. Therefore, online sales from distributors with offline stores have also increased, and the offline retailers are facing their limits in dealing with store-based online channel they have carried out. Domestic offline retailers benchmarked overseas advanced retailers to solve this problem by reviewing about developing the online-only distribution center. However, much investment is needed in order to operate the distribution center with the new concept from abroad. In this study, we have reviewed the current online grocery market trend and the theory related to developing distribution system of the online mall. For offline retailers, we have reviewed the case which developed the distribution center applied to the nation's first online-only distribution center. The purpose of this study is reducing trial and error for local retailers in developing online-only distribution centers and suggesting ways to improve investment effect.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.26 no.2
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• pp.68-83
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• 2017

With the increasing popularity of dental CAD / CAM, the kinds of materials that can be used and the range that can be utilized are also increasing. One of the biggest advantages of a dental CADCAM is that you can make a final prosthesis with one visit, but in case of zirconia or a complex aesthetic prosthesis, it is often difficult to make it in one day. In this case, temporary PMMA material can be used to provide a temporary crown with aesthetic and functional properties to the patient and can be used as a test crown or template for the final prosthesis. And if you are with a 5-axis milling machine in a clinic, you can make a temporary crown precisely to a large extent in a short time. In this article, various applications and clinical cases of PMMA temporary crown in the clinic will be presented.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.127-130
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• 2002

The 2.5 vol% TiNi/6061Al composites were fabricated by permanent mold casting, and its microstructures and tensile test for the cold rolled composites with maximum 50% reduction ratio were investigated. In the case of TiNi fiber with 2mm interval in preform, the interface bonding of fabricated composites were good. EPMA analysis results were found the small amount of Mg, Si segregated interface of diffusion layer. Transverse section of TiNi fiber was decreased with increasing reduction ratio and 40% reduction ratio was observed microcrack from TiNi fiber. And the tensile strength of composites at 38% reduction ratio was 194MPa. In the case of over 38% reduction ratio, the decrease of the tensile strength was due to TiNi fiber rupture by excess working. The fracture mode was appeared brittle fracture with increasing reduction ratio

• Journal of Environmental Health Sciences
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• v.8 no.1
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• pp.55-60
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• 1982

This study was carried out in order to clarify the combined effect of cadmium and lead on rat bones when exposed to single metal (1 mg cd/kg body weight) and cambined metals (1 mg cd + 4 mg pb/kg body weight). Seventy five mature rats of Sprague-Dawley species were divided into a control group and a treatment group that were administered by daily peritoneum injection for 7 to 9 weeds, and their body weights were measured every week. The results were summarized as follows 1. Body weight gains of the combined injection group and the single injection groups were lower than that of the control group. 2. In case of the combined injection group, the amount of cadmium accumulated in femur was more than that of the cadmium group. These amounts of cadmium accumulated showed an increasing trend. 3. The lead amount in bone tissue of the combined injection group presented also an increasing trend. In this case, the additive action of cadmium to the lead accumulation in bone tissue was conspicuous. 4. The amounts of calcium and phosphorus in femur showed clear a decreasing trend in the cadmium group and combined administration group. The ratio of calcium and phosphorus (ca/p) in the cadmium group was not different from that of the control group, but in the combined injection group the ratio was a little lower.