• 한국분말재료학회지
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• 제11권2호
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• pp.143-148
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• 2004

In the present study, $TiO_2$ imbedded composite powders have been successfully prepared from the (Cu. Zn)/$TiO_2$ composite salt solution. The composite (Cu, Zn)/$TiO_2$ powders were formed by drying the solution at 200~$600^{\circ}C$ in the hydrogen atmosphere. Photocatalytic characteristics was evaluated by detecting the decomposition ratio of aniline blue with UV-visible spectrophotometer(Shimazu Co., UV-1601). Phase analysis of (Cu, Zn)/$TiO_2$ composite powders was carried out by XRD and DSC, and powder size was measured with TEM. The mean particle size of composite powders was about 100mm. As the reduction temperature increases, a few zinc sulfide and oxide phases was formed and copper oxide phase was reduced. The decomposition ratio of aniline blue was about 80％ under the UV irradiation by the TiO$_2$ phase in the composite (Cu, Zn)/$TiO_2$ powders and similar decomposition ratio of 80％ was obtained at the UV lightless condition by virtue of Cu and Zn compounds.

• 공업화학
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• 제24권4호
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• pp.357-362
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• 2013

High efficiency particulate air (HEPA) 필터를 시험하기 위하여 단분산 polystyrene latex spheres (PLS) 및 PS-MPS/실리카복합 나노구체가 이용되었다. 사용된 모든 나노구체들은 필터시험 전에 평균입경과 변동계수 값을 측정하여 시험용 인조먼지로서 적정함을 평가하였다. PLS 및 복합 나노구체의 입경은 유화중합 중 반응온도와 안정제의 양을 조절하여 100~300 nm 범위에서 잘 조절되었으며, 변동계수의 경우도 단분산 입자분포로 판단되는 15%보다 낮은 3~7% 범위이었다. 한편 HEPA 필터시험 결과는 사용된 모든 나노구체들이 공기필터의 시험을 위한 시험용 인조먼지로서 아주 적절함을 보여주었다.

• Korean Chemical Engineering Research
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• 제54권4호
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• pp.459-464
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• 2016

본 연구에서는 리튬이온 전지용 실리콘 음극소재의 사이클 안정성 및 율속 특성 향상을 위해 다공성 실리콘/탄소 복합소재의 전기화학적 특성을 조사하였다. 나노 실리카 제조는 스토버 방법을 사용하고 교반 속도, 교반 온도 및 $NH_3$/TEOS 비율을 조절 하여 100~500 nm 크기의 구형 실리카를 합성하였다. 구형 나노 실리카의 마그네슘 열환원과 산처리 과정을 통해 다공성 실리콘을 얻고, 제조된 다공성 실리콘에 Phenolic resin을 탄소전구체로 사용하여 최종적으로 다공성 실리콘/탄소 활물질을 합성하였다. 또한 $LiPF_6$ (EC:DMC:EMC=1:1:1 vol%) 전해액에서 다공성 실리콘/탄소 음극소재의 충 방전, 순환전압 전류, 임피던스 테스트 등의 전기화학적 특성을 조사 하였다. 다공성 실리콘/탄소 복합소재의 음극활물질로서 코인 전지의 성능을 조사한 결과 초기용량 및 40사이클 용량 보존율은 각각 2,006 mAh/g, 55.4%를 나타내었다.

• 한국수소및신에너지학회논문집
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• 제22권5호
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• pp.569-578
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• 2011

The $SiO_2$ membranes for polymer electrolyte membrane fuel cell (PEMFC) are preapared by electrospinning method. It leads to high porosity and surface area of membrane to accommodate the proton conducting materials. The composite membrane was prepared by impregnating of Nafion ionomer into the pores of electrospun $SiO_2$ membranes. The $SiO_2$:heteropolyacid (HPA) nano-particles as a inorganic proton conductor were prepared by microemulsion process and the particles are added to the Nafion ionomer. The characterization of the membranes was confirmed by field emission scanning electron microscope (FE-SEM), thermogravimetry analysis (TGA), and single cell performance test for PEMFC. The Nafion impregnated electrospun $SiO_2$ membrane showed good thermal stability, satisfactory mechanical properties and high proton conductivity. The addition of the $SiO_2$:HPA nano-particle improved proton conductivity of the composite membrane, which allow further extension for operation temperature in low humidity environments. The composite membrane exhibited a promising properties for the application in high temperature PEMFC.

• Composites Research
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• 제23권6호
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• pp.1-6
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• 2010

복합재 항공기 동체의 낙뢰손상방지를 목적으로 탄소섬듐-주석 산화물(ITO) 나노입자를 코팅함으로써 탄소섬유강화플라스틱(CFRP) 복합재료의 전기전도도를 향상하였다. 탄소섬유에 코팅된 ITO 나노입자는 10~40%의 농도로 콜로이드 상태에서 분사되었다. CFRP의 전기전도도는 코팅 후 3배 이상 증가하였으며 현재 B-787 복합재 항공기 동체에 사용 중인 기술인 금속메쉬를 CFRP 외층에 매몰한 경우보다도 높은 전기전도도를 얻을 수 있었으며, 나노입자 코팅으로 섬유-기지 계면에 미지는 악영향은 발견되지 않았다. 모의 낙뢰에 의한 손상영역은 각각 다른 처리를 한 재료와 조건에 따라 초음파 C-scan 이미지로 확인하였다. ITO 40% 코팅 시편의 경우 전기전도도는 B-787 샘플의 경우보다 높았지만 낙뢰에 의한 손상영역의 크기는 거의 비슷한 수준이었다.

• Journal of Electrochemical Science and Technology
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• 제14권4호
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• pp.377-387
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• 2023

Ni-W/Al₂O₃ nano-composites were electrodeposited on mild steel substrate for mechanical and corrosion resistance applications. This study focused on the preparation of Ni-W/Al₂O₃ nano-composite coating with various quantity of Al₂O₃ incorporations. The addition of Al₂O₃ in the electrolytes were varied from 1-10 g/L in electrolytes and the Al₂O₃ incorporation in Ni-W/Al₂O₃ nano-composite coatings were obtained from 1.82 to 13.86 wt.%. The incorporation of Al₂O₃ in Ni-W alloy matrix influenced the grain size, surface morphology and structural properties were observed. The distributions of Al₂O₃ particle in alloy matrix were confirmed using electron microscopy (FESEM and TEM) and EDAX mapping analysis. The crystal structure informations were studied using X-ray diffraction method and it confirms that the deposits having cubic crystal structure. The better corrosion rate (0.87 mpy) and microhardness (965 HV) properties were obtained for the Ni-W/Al₂O₃ nano-composite coating with 13.86 wt.% of Al₂O₃ incorporations.

• 한국세라믹학회지
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• 제37권3호
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• pp.280-287
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• 2000

Adsorption behavior and amount of phenolic resin followed silica (SiO2) formation onto silicon nitride(Si3N4) surface were investigated using electrokinetic sonic amplitude (ESA) technique and with UV spectrometer, to fabricate Si3N4/SiC nano-composite based on reaction between SiO2 formed and phenolic resin absorbed onto Si3N4 particle. The amount of SiO2 formed and carbon from phenolic resin absorbed onto Si3N4 surface were calculated quantitatively to adjust the reaction between SiO2 and phenolic resin, resulting in no residual SiO2 and carbon. As a result, pre-heated tempeature for optimized reaction was below 25$0^{\circ}C$, in which there was no residual SiO2 and carbon.

• Journal of Magnetics
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• 제20권2호
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• pp.138-147
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• 2015

The unique nano-scale inter-lamellar microstructure and unparalleled heat treatment process give our developed metal powder composite its outstanding magnetic property for power inductor & motor applications. Compared to the conventional polycrystalline Fe or amorphous Fe-Cr-Si-B alloys, our unique designed inter-lamellar microstructure strongly decreases the intra-particle eddy current loss at high frequencies by blocking the mutual eddy currents. The combination of optimum permeability, magnetic flux and extremely low core loss makes this powder composite suitable for high frequency applications well above 10 MHz. Moreover, it can be also possible to SMC core for high speed motor applications in order to increase the motor efficiency by decreasing the core loss.

• 한국분말재료학회지
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• 제19권2호
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• pp.122-126
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• 2012

The Fe-based self-fluxing alloy powders and TiC particles were ball-milled and subsequently compacted and sintered at various temperatures, resulting in the TiC particle-reinforced Fe self-fluxing alloy hybrid composite, and the microstructure and micro-hardness were investigated. The initial Fe-based self-fluxing alloy powders and TiC particles showed the spherical shape with a mean size of approximately 80 ${\mu}m$ and the irregular shape of less than 5 ${\mu}m$, respectively. After ball-milling at 800 rpm for 5 h, the powder mixture of Fe-based self-fluxing alloy powders and TiC particles formed into the agglomerated powders with the size of approximately 10 ${\mu}m$ that was composed of the nanosized TiC particles and nano-sized alloy particles. The TiC particle-reinforced Fe-based self-fluxing alloy hybrid composite sintered at 1173 K revealed a much denser microstructure and higher micro-hardness than that sintered at 1073 K and 1273 K.

• 공업화학
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• 제21권6호
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• pp.670-675
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• 2010

나노실리카볼 입자를 합성하고 표면에 비닐기를 부여하는 합성 연구를 통해 다양한 크기로 조절이 된 유-무기하이브리드 입자인 비닐-나노실리카볼이 합성되었다. 다양한 크기의 비닐-나노실리카볼 입자를 상업적으로 적용되고 있는 아크릴-멜라민 클리어코트에 후첨시키고 경화시켰을 때, 클리어코트의 광택도 증가 및 유지 특성에 대해 연구하였다. 실리카볼 입자가 250 nm 정도인 경우 Matting effect에 의한 광택도 감소가 관측되었으나 20~30 nm로 작아지면 광택도 유지 효과가 약 7%까지 증가하였다. 나노실리카볼 대신 상업용 친수 실리카 Aerosil 200 (Hydrophilic fumed silica, 평균입도 12 nm, Degussa)을 사용하여 비닐- fumed 실리카 화합물을 합성하여 클리어코트에 적용하면 광택도 유지 효과가 약 2% 정도만 증가하였다.