• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.220.1-220.1
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• 2007

• Journal of the Korean institute of surface engineering
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• v.47 no.6
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• pp.293-296
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• 2014

Fe-Ni has been of great interest because it is known as one of low thermal expansion alloys as various application areas. This alloy was fabricated by electroforming process, and effect of heat treatment on thermal expansion and hardness was investigated. Nano-crystalline structure of 13.3 - 63.5 nm in size was observed in the as-deposited alloy. To investigate the effect of heat treatment on grain growth and mechanical/thermal properties, we conducted hardness and coefficient of thermal expansion (CTE). From this, we confirmed these properties were varied by heat treatment. In this nano-crystalline alloy, we could observe abnormal behavior in thermal expansion between $350-400^{\circ}C$. Additionally, an abrupt change in hardness has also been observed. However, once the grains grow up to micro-sized the mechanical and thermal properties mentioned above were stabilized similar to those of bulk alloys due to heat treatment.

• Journal of Powder Materials
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• v.10 no.1
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• pp.51-56
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• 2003

To investigate the effect of the parameters of the plasma arc discharge process on the particle formation and particle characteristics of the iron nano powder, the chamber pressure, input current and the hydrogen volume fraction in the powder synthesis atmosphere were changed. The particle size and phase structure of the synthesized iron powder were studied using the FE-SEM, FE-TEM and XRD. The synthesized iron powder particle had a core-shell structure composed of the crystalline $\alpha$-Fe in the core and the crystalline $Fe_3O_4$ in the shell. The powder generation rate and particle size mainly depended on the hydrogen volume fraction in the powder synthesis atmosphere. The particle size increased simultaneously with increasing the hydrogen volume fraction from 10% to 50%, and it ranged from about 45nm to 130 nm.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.286.1-286.1
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• 2013

Nowadays, the glare towards the light-emitting diode (LED) lighting source has much attention due to its eco-friendly nature, reduced energy consumption, and low CO2 emission. LEDs can show versatile colors by changing the composition ratio of semiconductors. Phosphors re-emit light by absorbing light from LED, which is the key factor for emission. The endeavor to make replica of natural white light is increasing day by day. Industrially, blue LED chip crowned with a yellow phosphor coated lens gives low quality white light. Newly, many researchers are introducing modern approaches, adding red phosphor to the yellow phosphor to increase the quality of white light. Here, we synthesized structurally and chemically stable europium doped oxyapatite Ca8Gd2(PO4)6O2 nano-crystalline structures by a hydrothermal method. The ultrafine structures were formed due to the effect of ethylenediaminetetraacetic acid, which is confirmed by the transmission electron microscope images. The structural properties were analyzed using the X-ray diffraction patterns.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.419-420
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• 2008

In this work, we report several experimental data capable of evaluating the phase transition characteristics of (InTe)x(GeTe)y (x = 0.1, 0.3, y =1) pseudo-binary thin films. (InTe)x(GeTe)y phase change thin films have been prepared by thermal evaporator. The crystallization characteristics of amorphous (InTe)x(GeTe)y thin films were investigated by using nano-pulse scanner with 658 nm laser diode (power : 1~17 mW, pulse duration : 10~460 ns) and XRD measurement. It was found that the crystalline speed of In-Ge-Te thin films are faster than $Ge_2Sb_2Te_5$[1] and also the crystalline temperature is higher. Changes in the optical transmittance of as-deposited and annealed films were measured using a UV-VIS-IR spectrophotometer and four-point probe was used to measure the sheeresistance of InGeTe films annealed at different temperature.

• Current Photovoltaic Research
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• v.11 no.3
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• pp.75-78
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• 2023

Recently, the installation of photovoltaic modules in urban areas has been increasing. In particular, the demand for solar modules installed in a limited space is increasing. However, since the crystalline silicon solar module's size is proportional to the solar cell's size, it is difficult to manufacture a module that can be installed in a limited area. In this study, we fabricated a solar module with a shingled design that can control horizontal and vertical width using a bi-directional laser scribing method. We fabricated a string cell with a width of 1/5 compared to the existing shingled design string cells using a bi-directional laser scribing method, and we fabricated a solar module by connecting three strings in parallel. Finally, we achieved a conversion power of 5.521 W at a 103 mm × 320 mm area.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.7-7
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• 2010

Indium tin oxide (ITO) - SWNT nano crystalline composites was synthesized at low temperature(${\sim}250^{\circ}C$)using Nano Cluster Deposition technique by Metal Orhoganic Chemical Vapor Deposition method. XRD patterns of ITO- SWNT composite shows pure cubic phases without any secondary phase. I-V measurement gives resistance of 12 ohms for Sn doped (3 wt %) indium oxide-SWNT composites. The electrical conductivity of the nano composites is significantly enhanced compared to the SWNT.

• Journal of Korea Foundry Society
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• v.28 no.6
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• pp.261-267
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• 2008

In-situ quasicrystalline icosahedral (I) phase reinforced Ti-based bulk metallic glass (BMG) matrix composites have been successfully fabricated by using two distinct thermal histories for BMG forming alloy. The BMG composite containing micron-scale Iphase has been introduced by controlling cooling rate during solidification, whereas nano-scale I-phase reinforced BMG composite has been produced by partial crystallization of BMG. For mechanical properties, micron-scale I-phase distributed BMG composite exhibited lower strength and plasticity compared to the monolithic BMG. On the other hand, nano-scale icosahedral phase embedded BMG composite showed enhanced strength and plasticity. These improved mechanical properties were attributed to the multiplication of shear bands and blocking of the shear band propagation in terms of isolation and homogeneous distribution of nanosize icosahdral phases in the glassy matrix, followed by stabilizing the mechanical and deformation instabilities.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.29-54
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• 2005

Consolidation of ceramic particles at room temperature. Reduction of crystallite size and formation of nano-crystalline. Applicable to Integrate functionalceramic materials with metals and Si structure and to fabricate MEMS devises

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.513-514
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• 2010