• 한국재료학회:학술대회논문집
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• 한국재료학회 2001년도 춘계학술발표강연 및 논문개요집
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• pp.147-147
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• 2001

• 한국정밀공학회지
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• 제29권7호
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• pp.799-804
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• 2012

Recently micro-nano structures has widely been reported to improve the performance of waterproof, heat isolation, sound and light absorption in various fields of electric devices such as mobiles, battery, display and solar panels. A lot of micro-sized holes on the surface of thin film provide excellent sound, or heat, or light transmission efficiency more than solid film and simultaneously nano-sized protrusions around micro hole increase the hydrophobicity of the surface of thin film because of lotus leaf effects as generally known previously. In this paper new rapid fabrication process with 355 nm UV laser ablation was proposed to get micro-nano structures on the surface of thin film, which have only been observed at higher laser fluence. Developed thin micro-nano structured film was also investigated the hydrophobic property by measuring the contact angle and demonstrated the possibility to apply to water droplet separation.

• 한국정보통신학회논문지
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• 제10권9호
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• pp.1641-1647
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• 2006

나노입자 크기를 가진 얇은 $SnO_2$ 박막을 이용하여 CO 및 $H_2S$에 대한 우수한 감도를 가지는 복합 마이크로 가스센서 어레이를 제작하였다. 나노입자의 박막을 만들기 위해서 약 $2500{\AA}$ 두께의 $SnO_2,\;SnO_2(+Pt),\;SnO_2(+CuO)$ 막을 셰도우마스크를 사용하여 형성 한 후, 이를 $600{\sim}800^{\circ}C$의 온도에서 산화하므로서 나노입자의 $SnO_2$ 모물질의 가스감지 박막을 형성하였다. 실리콘 기판의 마이크로센서의 형태로 제작된 $SnO_2(Pt)$ 및 $SnO_2(+CuO)$ 가스센서는 각각 CO 및 $H_2S$ 가스에 대한 매우 우수한 감도를 나타내는 것을 확인하였다.

• 한국분말재료학회지
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• 제20권2호
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• pp.100-106
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• 2013

Ultra-fine zirconium carbide (ZrC) powder with nano-sized primary particles was synthesized by the carbothermal reduction method by using nano-sized $ZrO_2$ and nano-sized graphite powders mixture. The synthesized ZrC powder was well dispersed after simple milling process. After heat-treatment at $1500^{\circ}C$ for 2 h under vacuum, ultra-fine ZrC powder agglomerates (average size, $4.2{\mu}m$) were facilely obtained with rounded particle shape and particle size of ~200 nm. Ultra-fine ZrC powder with an average particle size of 316 nm was obtained after ball milling process in a planetary mill for 30 minutes from the agglomerated ZrC powder.

• 한국전기전자재료학회논문지
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• 제18권8호
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• pp.708-713
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• 2005

An alumina membrane with nano-sized pore array by anodic oxidation using the thin film aluminum deposited on silicon wafer was fabricated. It Is important that the sample prepared by metal deposition method has a flat aluminum surface and a good adhesion between the silicon wafer and the thin film aluminum. The oxidation time was controlled by observation of current variation. While the oxalic acid with 0.2 M was used for low voltage anodization under 100 V, the chromic acid with 0.1 M was used for high voltage anodization over 100 V. The nano-sized pores with diameter of $60\~120$ nm was obtained by low voltage anodization of $40\~80$ V and those of $200\~300$ nm was obtained by high voltage anodization of $140\~200$ V. The pore widening process was employed for obtaining the one-channel with flat surface because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of two-channel with rough surface. Finally, the sample was immersed to the phosphoric acid with 0.1 M concentration to etching the barrier layer.

• 한국분말재료학회지
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• 제5권4호
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• pp.334-339
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• 1998

In purpose of introducing the inverse magnetostrictive properties into the structural ceramics, $Al_2O_3$ based nanocomposites dispersed with nano-sized Ni-Co particles were studied. The composites were fabricated by the hydrogen reduction and hot-pressing of $Al_2O_3$ and NiO-CoO mixed powders. The mixtures were prepared by using Ni- and Co-nitrate $(Ni(NO_3)_2\;{\cdot}\;6H_2O\;and\;Co(NO_3)_2\;{\cdot}\6H_2O)$ as source materials for the Ni-Co particles. Microstructural observations revealed that nano-sized Ni-Co particles were dispersed homogeneously at $Al_2O_3$ grain boundaries. High strength above 1 GPa was obtained for the $Al_2O_3/10$ wt% Ni-Co nanocomposite fabricated by a controlled powder preparation process. The inverse magnetostrictive response to applied stress was obtained due to the presence of dispersed Ni-Co particles, which indicates a possibility to incorporate new functions into the structural ceramics without loosing the mechanical properties.

• 한국분말재료학회지
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• 제15권4호
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• pp.302-307
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• 2008

$Gd_2O_3$-doped $CeO_2$(GDC) solid solutions have been considered as a promising materials for electrolytes in intermediate-temperature solid oxide fuel cells. In this study, the nano-sized GDC powder with average panicle size of 69nm was prepared by a high energy ball milling process and its sintering behavior was investigated. Heat-treatment at $1200^{\circ}C$ of nano-sized GDC powder mixture led to GDC solid-solution. The enhanced densification over 96% of relative density was obtained after sintering at $1300^{\circ}C$ for 2h. It was found that the sinterability of GDC powder could be significantly improved by the introduction of a high energy ball milling process.

• 한국재료학회지
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• 제16권9호
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• pp.538-542
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• 2006

Nano-sized cobalt oxide powders were prepared by low pressure spray pyrolysis process. The precursor powders obtained by low pressure spray pyrolysis process from the spray solution with ethylene glycol had several microns size and hollow structure. The precursor powders obtained from the spray solution with optimum concentration of ethylene glycol formed the nano-sized cobalt oxide powders with regular morphology after post-treatment without milling process. On the other hand, the cobalt oxide powders obtained from the spray solution without ethylene glycol had submicron size and spherical shape before and after posttreatment. The mean size of the cobalt oxide powders formed from the spray solution with concentration of ethylene glycol of 0.7M was 180 nm after post-treatment at temperature of $800^{\circ}C$. The mean size of the powders could be controlled from several tens nanometer to micron sizes by changing the post-treatment temperatures in the preparation of cobalt oxide powders by low pressure spray pyrolysis process.

• 한국수소및신에너지학회논문집
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• 제22권4호
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• pp.504-511
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• 2011

Nano-sized Sn powder was prepared by pulsed wire evaporation method. The Sn powder and carbon black were charged in jar and ball milled. The milling time was varied with 10 min., 1h, 2h, and 4h, respectively. The milled powders were dried and the shape and size were observed by FE-SEM. Nano-sized Sn powders were plastic-deformed and agglomerated by impact force of balls and heat generated during the SPEX milling. The agglomerated Sn powder also consisted of many nano-sized particles. Initial discharge capacities of milled Sn electrode powders with carbon powder were milled for 10 min., 1h, 2h, and 4h were 787, 829, 827, and 816 mAh/g, respectively. After 5 cycle, discharge capacities of Sn electrode powders with carbon powder milled for 10 min., 1h, 2h, and 4h decreased as 271, 331, 351, and 287 mAh/g, respectively. Because Sn electrode powders milled for 2h constist of uniform and fine size, the cyclability of coin cell made of this powders is better than others.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1874-1879
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• 2008

It is not easy to detect nano-sized airborne particles (< 100 nm in diameter) in air. Therefore, the condensation of the nanoparticles alongside of the size-classification is needed for their detection. This paper proposes a hybrid (aerodynamic+electrical) particle classification and condensation device using a micro virtual impactor (${\mu}VI$). The ${\mu}VI$ can classify the nanoparticles according to their size and condense the number concentration of nanoparticles interested. Firstly, the classification efficiency of the ${\mu}VI$ was measured for the particles, polystyrene latex (PSL), ranging from 80 to 250 nm in diameter. Secondly, the nanoparticles, NaCl of 50 nm in diameter, were condensed by 4 times higher. In consequence, the output signal was amplified by 4 times (before condensation: 4 fA, after condensation: 16 fA). It is expected that the proposed device will facilitate the detection of nanoparticles.