• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2004년도 International Symposium on Powder Materials and Processing
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• pp.30-31
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• 2004

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1219_1220
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• 2009

In recent years, the companies of electric power equipment for MV, HV class trend to develop that the eco-friendly insulated(solid, eco-gas, air etc.) switchgear replace with existent SF6 gas insulated switchgear by environmental problems such as global warming and soon. This paper introduces the Solid Insulated Switchgear(SIS) which is the epoxy of eco-friendly insulation material. The characteristic of SIS to introduce in this paper is as following. 1) Eco-friendly. (SF6 gas free) 2) The structure of flexible system. (Expansion) 3) The optimum design. (The Analysis of electrical & mechanical) 4) An Interface treatment between epoxy and insert. (Molding technology) This paper described about some technology for development of SIS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.919-921
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• 2000

This paper considers the research of the hybrid interrupter which adopts both rotating arc and thermal expansion technology. The operating principle of this device depends on rapid arc rotation due to the magnetic field created by the fault current through a coil which is mounted on contacts and also relies on the principle of thermal expansion created by arc energy in extinguishing chamber and finally causes pressure rise in expansion volume. In this research, the principle of the interrupting techniques are given and experimental results of hybrid interrupter which is developed by new technology is introduced.

• 한국분말재료학회지
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• 제25권3호
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• pp.246-250
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• 2018

In this study, we investigate the deformation behavior of $Hf_{44.5}Cu_{27}Ni_{13.5}Nb_5Al_{10}$ metallic glass powder under repeated compressive strain during mechanical milling. High-density (11.0 g/cc) Hf-based metallic glass powders are prepared using a gas atomization process. The relationship between the mechanical alloying time and microstructural change under phase transformation is evaluated for crystallization of the amorphous phase. Planetary mechanical milling is performed for 0, 40, or 90 h at 100 rpm. The amorphous structure of the Hf-based metallic glass powders during mechanical milling is analyzed using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Microstructural analysis of the Hf-based metallic glass powder deformed using mechanical milling reveals a layered structure with vein patterns at the fracture surface, which is observed in the fracture of bulk metallic glasses. We also study the crystallization behavior and the phase and microstructure transformations under isothermal heat treatment of the Hf-based metallic glass.

• 대한산업공학회지
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• 제41권2호
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• pp.150-161
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• 2015

This paper proposes a new approach to technology valuation, the market-replacement cost approach which integrates the cost-based approach and market-based approach. The proposed approach estimates the market-replacement cost of a target technology using R&D costs of similar R&D projects previously conducted. Similar R&D projects are extracted from project database based on document similarity between project proposals and technology description of the target technology. R&D costs of similar R&D projects are adjusted by mirroring the rate of technological obsolescence and inflation. Market-replacement cost of the technology is then derived by calculating the weighted average of adjusted costs and similarity values of similar R&D projects. A case of "Prevention method and system for the diffusion of mobile malicious code" is presented to illustrate the proposed approach.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2005년도 추계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.31-32
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• 2005

• 산업경영시스템학회지
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• 제44권3호
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• pp.248-261
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• 2021

Scientific and technological performances (e.g., patents and publications) made through R&D play a pivotal role for national economic growth. National governments encourage academia-industry cooperation and thereby pursue continuous development of science technology and innovation. Increasing R&D-related investments and manpower are crucial for national industrial development, but evidence of poor performance in business performance, efficiency, and effectiveness has recently been found in Korea. This study evaluates performance efficiency of the 6T sector (Information Technology, Bio Technology, Nano Technology, Space Technology, Environment Technology, Culture Technology), which is considered a high-potential promising industry for the next generation growth and currently occupies two thirds of the national R&D projects. The study measures the relative efficiency of R&D in a comparative perspective by employing the Data Envelopment Analysis (DEA) method. The result reveals overall low efficiency in basic R&D (0.2112), applied R&D (0.2083), development R&D (0.2638), and others (0.0641), confirming that economic performance and efficiency were relatively poor compared to production efficiency. Efficient R&D needs policy makers to create strategies that can increase overall efficiency by improving productivity performance and quality while increasing economic performance.

• Journal of Welding and Joining
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• 제35권3호
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• pp.1-6
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• 2017

The effect of metal turnover (MTO) of electroless Ni plating bath on the brittle fracture behavior of electroless nickel electroless palladium immersion gold (ENEPIG)/Sn-3.0wt%Ag-0.5wt%Cu(SAC305) solder joint was evaluated in this study. The MTOs of the electroless Ni for the ENEPIG surface finish were 0 and 3. As the MTO increased, the interfacial IMC thickness increased. The brittle fracture behavior of the ENEPIG/SAC305 solder joint was evaluated with high speed shear (HSS) test. The HSS strength decreased with increasing the MTO of the electroless Ni bath. The brittle fracture increased with increasing the shear speed of the HSS test. The percentage of the brittle fracture for the 3 MTO sample was much higher than that for the 0 MTO sample.

• Current Photovoltaic Research
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• 제8권4호
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• pp.120-123
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• 2020

Transparent photovoltaics (PV) are used in various applications such as building-integrated photovoltaics (BIPV). However, crystalline silicon (c-Si) is not used for developing transparent PV due to its opaque nature. Here. we fabficate the three holes in 6-inch c-Si solar cells using laser scribing process with an opening area ratio of about 6.8% for transparent c-Si solar modules. Moreover, we make the shingled strings using the perforated cells. Our 7 interconnected shingled string PV cells with 21 holes show a solar to power conversion of 5.721 W. In next work, we will fabricate a transparent c-Si PV module with perforated strings.

• Elastomers and Composites
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• 제57권3호
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• pp.100-106
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• 2022

Waterborne polyurethane-acrylate(WPUA) dispersions were prepared by surfactant-free emulsion polymerization in a two-step process. In the first step, polytetrahydrofuran, isophorone diisocyanate, dimethylol proponic acid, and 2-hydroxyethyl methacrylate were used to synthesize a vinyl-terminated polyurethane prepolymer. In the second step, styrene, methyl methacrylate, butyl acrylate, and different multi-functional crosslinkers were copolymerized. 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate were used as the crosslinkers, and their effect on the mechanical and thermal properties of WPUA was investigated. Overall, as the number of functional groups of the cross-linker increased, the gel fraction improved to 79.26%, the particle size increased from 75.9 nm to 148.7 nm, and the tensile strength was improved from 5.86 MPa to 12.40 MPa. In thermal properties, the glass transition temperature and decomposition temperature increased by 9.9℃ and 18℃, respectively. The chemical structures of the WPUA dispersions were characterized by Fourier-transform infrared spectroscopy. The synthesized WPUA has high potential for applications such as coatings, leather coatings, adhesives, and wood finishing.