• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.115-118
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• 2001

High-temperature superconductor films of YBa$_2$Cu$_3$$O_{7-x}$ were fabricated by electrophoretic deposition (EPD) from alcohol-based suspension. Maximum stability is observed for the suspension containing iso-alcohol as the dispersion medium. However, for the formation of a dense and adherent coating of YBCO on a silver substrate by EPD, the best results were obtained in mix PrOH and BuOH suspension. The superconducting critical current density (J$_{c}$) was 1200 A/cm$^2$ for a films deposited in 30% iso-PrOH and 70 % iso-BuOH suspension.ion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.988-991
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• 2002

ITO (Indium Tin Oxide) powder was synthesized by precipitation method. ITO colloidal solutions for coating on glass were fabricated by ball milling method. ITO colloidal solution with variation of concentration from 2% to 15% were fabricated ITO thin film measured sheet resistance and transmittance. In the result, 15% sol showed the lowest value of sheet resistance, 2% sol showed the highest value of transmittance. In addition, effect of annealing temperature and $SiO_2$ film were investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.212-213
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• 2006

BSCT(60/30/10) powder specimens were fabricated by sol-gel method and BSCT thick films were fabricated by screen-printing method. The coating and drying procedure was repeated 6 times. Then the structural properties as a function of the sintering temperature. As a result of the TG-DTA, exothermic peak was observed at around $670^{\circ}C$ due to the crystalline phase. The BSCT sintered at $1430^{\circ}C$ showed the cubic perovskite structure. The prosity and thickness of the BSCT thick films was decreased with sintering temperature. The thickness of BSCT thick films at $1420^{\circ}C$ was approximately $40{\mu}m$.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.568-569
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• 2003

Functional cosmetic ingredients such as L-ascorbic acid, retinoic acid, indole-3-acetic acid, salicylic acid, acidic dye(indigo carmine) are intercalatively encapsulated by skin-friendly metal hydroxides and oxides matrices. Such functional organic-inorganic nanohybrids are realized via chemical coprecipitation and surface coating reactions. The hetero-structural nature of these nanohybrids, their particle morphology and textural characterizations are mainly discussed on the basis of powder X-ray diffraction, electron microscopies, and high performance liquid chromatographic analyses. The cosmetic ingredients encapsulated in inorganics show greatly improved storage stability, sustained releasing property as well as higher transdermal transfer efficiency.

• Tribology and Lubricants
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• v.19 no.5
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• pp.274-279
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• 2003

$Al-SiC_{p}$ composite layer was prepared by plasma thermal spray on aluminum substrate. The homogeneously dispersed composite powder for thermal spray was fabricated by mechanical alloying with ball mill. The friction tests of the composite layers and commercial aluminum alloys for comparison were performed in the temperature range of 20∼$260^{\circ}C$ with the interval of $40^{\circ}C$ with steel counter-face. Friction coefficient was recorded during test sequence, and the microstructure of surface and debris was investigated by optical and scanning electron microscope. Friction coefficients of composite and aluminum alloys at room temperature were similar except pure aluminum. As the temperature increase, friction coefficient was increased rapidly in AC4C, AC2A. But friction coefficient of $Al-SiC_{p}$ composite was not increased so much up to $220^{\circ}C$. Consequently, the reinforcement of $SiC_{p}$ into aluminum matrix increased the stability of friction coefficient as well as wear resistance.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.97-107
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• 1998

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. Braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two sizes of brake discs in stop and hold braking modes. And Plasma spray coating technique was used to coat ceramic powder on the discs. In the test four commercial brake pads were coupled with discs. Ceramic coated discs had shown good stability in friction coefficient at high speed and high energy braking conditions. But they caused large pad mass wear loss compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc, it had shown fluctuating friction coefficient at high speed but a fittie pad mass wear loss compared with ceramic coated discs.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.88-93
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• 2007

Nano-sized Sn particles were coated with Ni-P layer using an electroless deposition method and their anodic performance was tested for lithium secondary batteries. Uniform coating layers were obtained, of which the thickness was controlled by varying the $Ni^{2+}$ concentration in the plating bath. It was found that the Ni-P layer plays two important roles in improving the anodic performance of Sn powder electrode. First, it prevents the inter-particle aggregation between Sn particles during the charge/discharge process. Second, it provides an electrical conduction pathway to the Sn particles, which allows an electrode fabrication without an addition of conductive carbon. A pseudo-optimized sample showed a good cyclability and high capacity ($>400mAh\;g^{-1}$) even without conductive carbon loading.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.815-820
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• 2001

According as industry is complex, architecture is changing into the complex and diverse style and also customer's demands are becoming diversified. Among these, a door field is very important as much as saying nothing of more explanation. In this paper, in order to develop large floor hinge, mechanical properties of component parts are measured by vickers hardness tester, microstructure analysis and at the same time, these are designed by the FEM analysis.

• Journal of the Korean Applied Science and Technology
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• v.24 no.4
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• pp.369-376
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• 2007

우리는 마이카, boron nitride, bismuthoxychloride와 같은 판상 분체에 ZnO 나노입자를 코팅한 고 기능성 무기 분체를 합성하였다. 본 실험에서 우리는 수열침전법을 이용하여 합성 분체를 합성하였다. 출발물질은 $ZnCl_2$를 사용하였고 침전제로는 hexamethylenetetramine(HMT)와 urea를 사용하였다. 본 실험의 반응변수로는 출발물질의 농도, 침전제 및 반응온도를 변화시켜 실험하였다. 합성물의 형태, 결정성 및 UV-차단능은FE-SEM, XRD, FT-IR, TGA-DTA, in vitro SPF 테스트를 활용해 분석하였다. 본 실험의 결과, 나토입자 크기를 갖는 ZnO는 동일한 최적의 합성조건하에서 다양한 판상 분체의 종류에 관계없이 균일하게 코팅되었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.295-295
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• 2010

Nanoparticles of the compound semiconductor, Cu(In, Ga)Se2 (CIGS), were synthesized in solution under ambient pressure below $100^{\circ}C$ and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), optical absorption spectroscopy and energy-dispersive X-ray (EDX) analyses. These materials have chalcopyrite crystal structures and the particle sizes less than 100 nm. Synthetic conditions were studied for the crystallized CIGS nanoparticles formation to prevent from side products of Cu2Se, Cu2-xSe, and CuSe etc. The single phase CIGS nanoparticles were applied to coating of thin films photovoltaic cells. The electro deposition of CIGS thin films is also a good non-vacuum technology and under investigation. In aqueous solutions, the different chemical compositions of CIGS thin films were obtained, depending on pH, concentration of starting materials and deposition potentials. The surface morphology of the prepared CIGS thin films depends on the complexing ligands to the solutions during the electrochemical deposition.