• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 하계학술발표회
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• pp.52-53
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• 2004

• 한국재료학회:학술대회논문집
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• 한국재료학회 2005년도 춘계학술발표대회 및 제8회 신소재 심포지엄 논문개요집
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• pp.66-66
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• 2005

• Transactions on Electrical and Electronic Materials
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• 제12권3호
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• pp.98-101
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• 2011

A 10 nm nano-silica was introduced to a conventional 3 ${\mu}M$ micro-silica composite to develop an eco-friendly new electric insulation material for heavy electric equipment. Thermal and mechanical properties, such as glass transition temperature (Tg), dynamic mechanical analysis, tensile and flexural strength, were studied. The mechanical results were estimated by comparing scale and shape parameters in Weibull statistical analysis. The thermal and mechanical properties of conventional epoxy/micro-silica composite were improved by the addition of nano-silica. This was due to the increment of the compaction via the even dispersion of the nano-silica among the micro-silica particles.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.392-393
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• 2006

Direct Printing Process is a suitable fabrication technique to develope pigment components whose dimensions are in nano. The success of this process depends on the sysmatic preparation of pigment millbase. Conventional millbase dispersions are constituted of the organic pigments, monomer, dispersant and solvents. An experimental study on the rheology of millbase dispersions is presented.

• 한국전기전자재료학회논문지
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• 제30권12호
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• pp.751-756
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• 2017

A molding-type power inductor is an inductor that uses a hybrid material that is prepared by mixing a ferrite metal powder coated with an insulating layer and an epoxy resin, which is injected into a coil-embedded mold and heated and cured. The fabrication of molding-type inductors requires various techniques such as for coil formation and insertion, improving the magnetic properties of soft magnetic metal powder, coating an insulating film on the magnetic powder surface, and increasing the packing density by well dispersing the powder in the epoxy resin. Among these aspects, researches on additives that can disperse the metal soft magnetic powder having the greatest performance in the epoxy resin with high charge have not been reported yet. In this study, we investigated the effect of silanes, KBM-303 and KBM-403, and a commercial dispersant on the dispersion of metal soft magnetic powders in epoxy resin. The sedimentation height and viscosity were measured, and it was confirmed that the silane KBM-303 was suitable for dispersion. For this silane, the packing density was as high as about 72.49%. Moreover, when 1.2 wt% of dispersant BYK-103 was added, the packing density was about 80.5%.

• Composites Research
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• 제29권6호
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• pp.353-357
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• 2016

B-stage 레진 필름에 탄소나노튜브(CNT) 등을 균일하게 분포시킨 뒤에 기타의 보강섬유 층과 함께 여러 겹으로 적층하여 하이브리드 형태의 복합재료를 만드는 방법은 유용하다. 본 연구에서는 CNT가 포함된 에폭시 레진으로부터 shear mixing 및 Three-roll mill 공정을 이용하여 B-stage 레진 필름을 제작하였다. 두 공정을 통해 형성된 CNT/레진 복합재 필름의분산도를 파단면의 SEM 관찰을통해분석하였다. 보다 효율적인 공정을 위해 Calendering pass 횟수에 따른 분산도를 평가하였다. Pass의 횟수에 따른 샘플을 제조하고 CNT 분산도는 SEM 이미지를 통해 확인하고, 전기 전도도 측정을 통해 분석하였다. 추가적으로 gap mode, force mode를 통해 제작한 각각의 샘플의 전기 전도도를 측정하여 CNT 분산도를 분석하였고 이를 통해 최적공정을 도출하였다.

• 한국분말재료학회지
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• 제8권3호
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• pp.163-167
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• 2001

A bulk porous $CaZrO_3/MgO$ composite with plantinum nano-dispersion was synthesized in air atmosphere through the combination of several in situ reactions, including the pyrolysis of $PtO_2$. A mixture of $CaMg(CO_3)_2$(dolomite), $ZrO_2$, $PtO_2$ and LiF (0.5 wt%, as an additive) was cold isostatically pressed at 200 MPa and sintered at $1100^{\circ}C$ for 2 h. The porous $CaZrO_3/MgO/Pt$ composite ($CaZrO_3/MgO$ : Pt=99 : 1 in volume) had a uniformly open-porous structure (porosity: 56%) with three-dimensional (3-D) network and a narrow pore-size distribution, similarly to the porous $CaZrO_3/MgO$ composites reported before. Catalytic Properties (viz., NO direct decomposition and NO reduction by $C_2H_4$) of the $CaZrO_3/MgO/Pt$ composite were investigated up to $900^{\circ}C$. In the absence of oxygen, the NO conversion rate reached ~52% for the direct decomposition and ~100% for the reduction by $C_2H_4$, respectively. The results suggest the possibility of the porous composite as a multifunctional filter, i.e., simultaneous hot gas-filtering and $de-NO_x$ in one component.

• Transactions on Electrical and Electronic Materials
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• 제13권3호
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• pp.116-120
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• 2012

In this paper, ZnO-Epoxy nanocomposites (NEP) were prepared and epoxy composites that contain 5 wt% micro ZnO (MEP) and deliberately not well dispersed nano ZnO (NDNEP) were also prepared for purpose of comparison. The effects of the particle size and dispersion of ZnO on dielectric properties of epoxy resin were chiefly studied. Test results showed that: at a loading of 5 wt%, the three epoxy composites seem to have no significant difference on resistivity compared to epoxy resin; Dielectric constants of all the epoxy composites are also basically the same but they are bigger compared to that of the pure epoxy resin (unfilled); Dielectric dissipation factors ($tan{\delta}$) of NDNEP is greater than that of NEP and MEP. NEP has the minimum dielectric loss factor, whereas dielectric loss factors of the three epoxy composites are larger than that of the pure epoxy resin. The decreasing order of electrical breakdown strength for the three epoxy composites and for the pure epoxy resin is as follows: NEP>MEP>NDNEP>EP. Finally, in order to explain the experimental results the aggregation interface phase was proposed. Furthermore, addition of well dispersed nano filler has proved to have a positive effect on the improvement of the dielectric properties of epoxy resin.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.324-327
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• 2005

An electrophoretic display using $TiO_2$ particles is the most promising candidate because it offers various advantages such as ink-on-paper appearance, good contrast ratio, wide viewing angle, image stability in the off-state and extremely low power consumption. The core technology of electrophoretic display is the dispersion controlling of $TiO_2$ nano particles in nonaqueous solution. To prepare an ink for electronic paper using electrophoretic properties of $TiO_2$ nano particles, cyclohexane with low dielectric constant and transparency, polyethylene for producing polymer coating layer which reduces apparent gravity of $TiO_2$, and $TiO_2$ powders were mixed together by planetary-mill. The zeta-potential value of $TiO_2$ particles in cyclohexane was measured about -40mV, but was measured over -110mV by dispersant attached to polyethylene-coated $TiO_2$ surface. Prepared electronic ink was filled in cross patterned micro-wall with $200{\mu}m$ in width and $40{\mu}m$ in height on ITO glass designed by photolithography. The response time of electronic paper evaluated by mobility of $TiO_2$ particle between micro-walls was measured 0.067sec, but the drift velocity from reflectance wave form during reverse from of electronic ink was measured 0.07cm/sec.

• 한국음향학회지
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• 제29권4호
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• pp.251-257
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• 2010

본 논문에서는 액체 매질 내 기포운에 의한 초음파의 감쇠 및 분산 특성을 다룬다. 액체 내 기포운은 다양한 기작에 의해 발생되며 이에 따라 기포운을 구성하는 기포들의 크기와 분포가 다양한 양상을 가지게 된다. 따라서 기포들의 크기와 분포에 따라 기포운의 감쇠와 분산 특성이 어떻게 변화하는지에 중점을 둔다. 특히 아직 보고된 바 없는 나노 기포운의 감쇠 및 분산 특성에 대하여 조명하고자 한다. 수치해석 결과, 기포운의 음향 감쇠 및 분산 특성은 구성 기포들의 첨예도에 따라 크게 변화하는 것으로 나타났다. 본 연구는 기포운 내 음향 전파의 심도 있는 이해에 일조할 것으로 기대한다.