• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.464-478
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• 2003

Free radicals and reactive oxygen species (ROS) caused by UV exposure or other environmental facts play critical roles in cellular damage and aging. The extract of tinged autumnal leaves of maple tree(Acer palmatum) has proven to be a powerful antioxidant. The Acer palmatum extract is very effective on the stabilization of biological membranes( containing unsaturated fatty acid). We studied photoprotective effect of the extract against UVB-induced cytotoxicity in human keratinocytes. The extract improved cell viability comparing to control after UVB irradiation. In the determination test of pro inflammatory cytokines the extract decreased expression of interleukin 1 a and 6, which play an important role in inflammation and skin erythema caused by UV. We also studied property of varying cosmetic formulations on the percutaneous absorption of the extract. After 24 hour in vitro penetration study, the content of the extract was more highly detected in skin residue part. This result showed the extract had relatively high compatibility of skin in our emulsion system. On human skin, after appling the product containing the extract we obtained a good result of antiwrinkle effect by skin visiometer. In conclusion, the Acer palmatum extract is a photoprotective and very effective in stressed and aged skin care. And we can predict the extract mainly affects on the skin cell and tissue in our emulsion system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.125-129
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• 2004

The mold transformers have been widely used in underground substations in large building and have some advantages in comparison to oil-transformer, that is low fire risk, excellent environmental compatibility, compact size and high reliability. In addition, the application of mold transformer for outdoor is possible due to development of epoxy resin. The mold transformer generally has cooling duct between low voltage coil and high voltage coil. A mold transformer made by one body molding method has been developed for small size and low loss, but it needs some cooling method because heat radiation between each winding is difficult. The life of transformer is significantly dependent on the thermal behavior in windings. Many transformer designers have calculated temperature distribution and hot spot point by FEM(finite element method) to analyze winding temperature rise. In this paper, the temperature distribution and thermal stress analysis of 100kVA pole cast resin transformer for power distribution are investigated by FEM program.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1135-1138
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• 2003

The transformer is major equipment in power receiving and substation facilities. Necessary conditions required for the transformer are compactness, lightness, high reliability, economic advantages, and easy maintenance. The pole-mount transformer installed in distribution system is acting direct role in supply of electric power and it is electric power device should drive for long term. Most of modem transformer are oil-filled transformer and accident is happening considerable. The mold transformers have been widely used in underground substations in large building and have some advantages in comparison to oil-transformer, that is low fire risk, excellent environmental compatibility, compact size and high reliability. In addition, the application of mold transformer for outdoor is possible due to development of epoxy resin. The mold transformer generally has cooling duct between low voltage coil and high voltage coil. A mold transformer made by one body molding method has been developed for small size and low loss. One body molding transformer needs some cooling method because heat radiation between each winding is difficult. In this paper, The thermal analysis of pole mount mold transformer with one body molding by duct condition is investigated and the test result of temperature rise is compared with simulation data.

• Steel and Composite Structures
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• v.33 no.3
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• pp.347-356
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• 2019

Most of the recent studies have improved the efficiency of FRP jackets for increasing the compressive strength, shear strength, and ductility of reinforced concrete columns; however, the influence of FRP jackets on the flexural capacity is slight. Although new methods such as NSM (near surface mounted) are utilized to solve this problem, yet practical difficulties, behavior dependency on adhesives, and brittle failure necessitate finding better methods. This paper presents the results of an experimental study on the application of fiber-reinforced polymer fastened mechanically to the concrete columns to improve the flexural capacity of RC columns. For this purpose, mechanical fasteners were used to achieve the composite behavior of FRP and concrete columns. The experimental program included five reinforced concrete columns retrofitted by different methods using FRP subjected to constant axial compression and lateral cyclic loading. The experimental results showed that the use of the new method proposed in this paper increased the flexural strength and lateral load capacity of the columns significantly, and good composite action of FRP and RC column was achieved. Moreover, the experimental results were compared with the results obtained from the analytical study based on strain compatibility, and good proximity was reached.

• Structural Engineering and Mechanics
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• v.51 no.4
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• pp.685-705
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• 2014

This paper presents a new formulation for forward scalar wave simulations in semi-infinite media. Perfectly-Matched-Layers (PMLs) are used as a wave absorbing boundary layer to surround a finite computational domain truncated from the semi-infinite domain. In this work, a hybrid formulation was developed for the simulation of scalar wave motion in two-dimensional PML-truncated domains. In this formulation, displacements and stresses are considered as unknowns in the PML domain, while only displacements are considered to be unknowns in the interior domain. This formulation reduces computational cost compared to fully-mixed formulations. To obtain governing wave equations in the PML region, complex coordinate stretching transformation was introduced to equilibrium, constitutive, and compatibility equations in the frequency domain. Then, equations were converted back to the time-domain using the inverse Fourier transform. The resulting equations are mixed (contain both displacements and stresses), and are coupled with the displacement-only equation in the regular domain. The Newmark method was used for the time integration of the semi-discrete equations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.4
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• pp.243-251
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• 2009

Refrigerant mixtures provide an opportunity to adjust their properties to fit design criteria and a possibility to create new blends that can improve heat transfer characteristics. Therefore, mixture of $CO_2$ and propane is chosen which may be a promising refrigerant and has good environmental compatibility. This paper presents measured heat transfer coefficient data during evaporation process of $CO_2$/propane mixtures flowing upward in vertical smooth and. micro-fin tubes. Smooth and micro-fin tubes with outer diameters of 5 mm and length of 1.44in were selected as test tubes. The tests were conducted at mass fluxes of 212 to $656kg/m^{2}s$, inlet temperatures of -10 to $30^{\circ}C$, heat fluxes of 15 to $60\;kW/m^2$ and for several compositions (75/25, 50/50, 25/75 wt%). Among $CO_2$/propane refrigerant mixtures, the heat transfer characteristics are much better than that of any compositions when the composition is 75/25 (wt%).

• Journal of Korea Trade
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• v.23 no.4
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• pp.131-148
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• 2019

Purpose - Based on the Korea-China FTA as the starting point, this paper makes an empirical analysis of the main influencing factors of the FTA utilization and performance of SMEs. Design/methodology - Taking into account the relationship between the internal and external environmental factors on FTA activities and performance of Korea's SMEs, with PLS-SEM and data obtained by the questionnaire, Smart PLS was applied for the analysis. Findings - The recognition of FTA in SMEs has a significant positive effect on FTA utilization and performance, the international marketing orientation factor only has a significant positive effect on the performance, while the inadequate improvement of non-tariff barriers has a significant negative impact on FTA utilization. In addition, FTA activity has a significant mediation effect on two paths. Originality/value - This paper is of great practical relevance as a tool to enable SMEs to make effective utilization of Korea-China FTA and improve their imports and exports. The paper helps grasp the main factors affecting the utilization and performance of FTA for SMEs, also to establish FTA Business Model and FTA utilization plans for specific industries in the future regarding tariff and non-tariffs compatibility.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.6
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• pp.158-163
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• 2018

Major producers have already built compressors since World War I and have been monopolizing all domestic and overseas markets based on the accumulated technology, and the dependency of the manufacturers over the entire industry is deepening. Therefore, it is expected that the technological gap with developed countries will be larger without development of the related technology. Therefore, it is necessary to develop a unique technology for a new type of high efficiency compression system. In this study, we present localization of Hydraulic Compressor which can meet the technical trends such as cost reduction, efficiency improvement, environmental friendliness, wide operating range, low capacity / high capacity compatibility, size reduction, easy operation and easy maintenance.

• The Journal of Society for e-Business Studies
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• v.24 no.1
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• pp.17-27
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• 2019

With the occurrence of the 4th Industrial Revolution, environmental change is happening in the healthcare industry as overall flow of Industry heads to ICT-based business environment. Healthcare Industry, which has the characteristic of public goods, is requiring a reliability and continuity of healthcare industry, however, the introduction of security is being delayed due to the problem of compatibility and extendability of existing system. Accordingly, in this research, we have built a section and role for stakeholders to be concerned in order to induce, analyze and introduce a needed security technology for rapidly building a security system in a smart healthcare environment. We have suggested a possibility of extendability regarding a multi-dimensional effort of stakeholders for establishing a healthcare security system.

• Journal of Korean Living Environment System
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• v.24 no.4
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• pp.533-540
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• 2017

This study analyzes the stretchability and clothing pressure of fabrics made from stretchy knit materials, and uses the baseline data to develop various functional clothing made from stretchy knit fabrics. To observe the changes in the stretchability and clothing pressure, we observed the compatibility of the two materials (tricot and power-net), presence of flat seam, fabric layering, and flat seam direction as key variables. A standard test method for stretch properties (ASTM D2594) was used for measuring the stretchability of the material. Clothing pressure measurements were analyzed in terms of the mean and standard deviation values, and the correlation of the stretchability. In the case of tricot, the presence of flat seam increased the stretchability of the fabric regardless of the fabric layering. However, when tricot and the less stretchable power-net were combined, the presence of flat seam did not increase the stretchability. Flat seam did not interfere with or limit the stretchability of the fabric, but they did increase the clothing pressure at the seam. The stretchability had a negative correlation with the clothing pressure except along the flat seam.