• Journal of the Korean Ceramic Society
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• v.41 no.7
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• pp.513-517
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• 2004

Porous alumina ceramics with aligned plate-shaped pores were fabricated by using thermoplastic microsphere in order to show the anisotropy in thermal conductivity. The mixed powder of alumina and microsphere was pressed under 15 MPa till 20$0^{\circ}C$ to deform polymer into platelet-shape and sintered at 1,00$0^{\circ}C$ for 1 h. The sintered specimen with 10 wt% microsphere has 45.3% porosity and the bending strength of 44 MPa. The microstructural investigation confirmed the pore structure of platelet-shape, the thermal conductivities for vertical and parallel directions are 3.803 W/mK and 7.818 W/mK, respectively, the ratio between two directions exceeds 2.

• Korean Journal of Materials Research
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• v.17 no.2
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• pp.107-114
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• 2007

Porous Ti compacts were fabricated by spark plasma sintering (SPS) method and their in vitro and in vivo biocompatibilities were investigated. Alkaline phosphatase (ALP) activity representing the activity of osteoblast was increased when osteoblast-like MG-63 cells were cultured on the Ti powder surface. Some genes related to cell growth were over-expressed through microarray analysis. The porous Ti compact with 32.2% of porosity was implanted in the subcutaneous tissue of rats to confirm in vivo cytotoxicity. 12 weeks post-operation, outer surface and inside the porous body was fully filled with fibrous tissue and the formation of new blood vessels were observed. No inflammatory response was confirmed. To investigate the osteoinduction, porous Ti compact was implanted in the femur of NZW rabbits for 4 months. Active in-growth of new bone from the surrounded compact bone was observed around the porous body. From the results, The porous Ti compacts fabricated by spark plasma sintering might be available for the application of the stem part of artificial hip joint.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.53-57
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• 2018

고도의 산업화에 따라 도시의 성장과 인구의 밀집으로 인하여 물의 수요가 증가하고 이에 따라 각종 오염원의 유입이 증가함에 따라서 적절한 수질 관리에 대한 필요성이 대두되고 있다. 그리고 산업이 다양화됨에 따라 배출되는 하 폐수의 특성도 다양해져 기존의 수질처리장은 효율적인 처리를 하는데 있어 많은 어려움이 발생되고 있다. 굴 패각은 하수처리의 담체로 이용할 경우 살수여상의 문제점 중 하나로 나타나는 막힘 현상을 다소 감소시킬 수 있고, 다공질체로서 표면적이 불규칙하고 비표면적이 크기 때문에 반응기내에 공기를 원활하게 공급할 수 있으며, 중금속 이온과 유기물에 대한 흡착 효율이 뛰어나 미생물이 쉽게 부착, 성장할 수 있는 장점을 가지고 있다. 천연광물질은 전 세계적으로 발견되어 활용된 역사가 짧지만, 그 특징은 산소결핍보충, 유해원소 흡착 성능, 반도체 작용, 인체 면역력 강화, 바이러스성 질병의 예방, 중금속 해독 등의 다양한 특징으로 환경호르몬 제고, 음이온 원적외선 발생으로 세포의 노화방지, 인체 노폐물 제거와 같은 특징을 지닌 매우 유용한 자원으로 확인되고 있으며, 수질정화 능력이 탁월한 것으로 보고 있다. 이에 본 연구는 어촌폐기물인 굴 패각과 수질정화에 탁월한 천연 광물질을 혼합하여 경제적이고, 효율성이 높은 다공성 수질개선 담체를 개발하고, 수목여과용 비점오염시설 장치에 적용하여 혼합 담체가 수처리 시설의 담체로서 사용이 가능한지, 수목여과용 비점오염시설 장치에 적용할 수 있는지 검토하고자 수행하였다. 이 연구는 2017년 중소기업청 기술개발사업에서 연구지원을 받아 연구되었습니다.

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1114-1118
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• 2000

Ti 및 C 입자로 이루어진 다공질 성형체에 용융 Si의 침윤 및 반응으로 새로운 Ti$_3$SiC$_2$합성공정이 개발되었다. 용융 Si 침윤에 의한 Ti$_3$SiC$_2$합성공정에서는 이제까지 연구된 합성방법 보다 넓은 조성 범위에서 Ti$_3$SiC$_2$의 합성이 이루어졌다. 용융 Si을 활성 매질로 사용한 Ti$_3$SiC$_2$의 합성에서는 성형체 조성, 원료 입자 크기 및 침윤되는 용융 Si의 양에 따라 합성되는 상 및 각 합성상의 양이 다르게 나타났다. Ti:Si:C=3:1:6 조성을 제외한 모든 조성의 시편에서 Ti$_3$SiC$_2$상이 합성되었으며, 일부 조성을 제외한 모든 조성의 시편에서 Ti$_3$SiC$_2$, TiC 및 SiC가 함께 합성되었다. 작은 Ti 입자로 이루어진 성형체를 사용하여 합성한 시편에서 Ti$_3$SiC$_2$상의 합성이 용이하게 이루어졌으며, 성형체 조성 및 침윤되는 Si의 양이 화학양론적으로 Ti$_3$SiC$_2$에 근접한 조성을 갖는 시편에서 Ti$_3$SiC$_2$를 높은 수율로 합성할 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.6 s.336
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• pp.23-30
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• 2005

In this paper, OPPS(oxidized porous poly-silicon) field emitters were fabricated by using various emitter-electrode metal and these electron emission characteristics were investigated for different thermal annealing effects. The addressed OPPS field emitter with Pt/Ti emitter electrode annealed at $300^{\circ}C$-1hr showed the efficiency of $2.98\%$ at $V_{ps}$=12 V and one annealed at $350^{\circ}C$-1hr showed the highest efficiency of $3.37\%$at $V_{ps}$=16V. They are resulted from the improvement of interfacial contact characteristics of thin emitter metal to an oxidized porous poly-silicon and the decrease of electrical resistance of emitter metal. The brightness of the OPPS field emitter increases linearly in $V_{ps}$ and after oxidation process for $900^{\circ}C$-50min, the brightness of the OPPS field emitter with the as-deposited Pt/Ti emitter electrode was 3600 cd/$m^2$ at the $V_{ps}$=15 V, 6260 cd/$m^2$ at the $V_{ps}$=20 V. Thermal treatment improved the adhesion between the Ti buffer layer and the oxidized porous poly-silicon and also played an important role in the uniform distribution of electric field to the emitter electrode.

• Journal of the Korean Ceramic Society
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• v.39 no.10
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• pp.948-954
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• 2002

Porous reaction bonded SiC with high fracture strength was developed using Si melt infiltration method for use of the support layer in high temperature gas filter that is essential to develop the next generation power system such as integrated gasification combined cycle system. The porosity and pore size of porous RBSC developed in this study were in the range of 32∼36% and 37∼90 ${\mu}m$ respectively and the maximum fracture strength of porous RBSC fabricated was 120 MPa. The fracture strength and thermal shock resistance of porous RBSC fabricated by Si melt infiltration were much improved compared to those of commercially available porous clay bonded SiC due to the formation of the strong SiC/Si interface between SiC particles. The characteristics of pore structure of porous RBSC was varied depending on the amounts of residual Si as Well as the size of SiC particle used in green body.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.113-118
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• 1999

Aluminum hydrates were synthesized using $AlCl_3$.$6H_2O$as starting material by precipitation method. The phases of obtained powder were amorphous, boehmite, bayerite, nordstrandite depending on the pH of solutions. Aluminum hydrates transformed to $\alpha-Al_2O_3$via $\gamma$- $Al_2O_3$,$\delta$- $Al_2O_3$,and $\theta$-$Al_2O_3$,and particle sizes were grown by increment of heating temperature. The TEX>$\gamma$- $Al_2O_3$ powder was coated on intermediate layer of ceramic membrane by the dip-coating method, and unsupported membrane was also prepared for comparison. The supported layer showed porous structure with small grains, but the unsupported layer revealed interconnected larger grains. Grain growth is dominant in the unsupported layer than in the supported one.

• Resources Recycling
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• v.7 no.3
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• pp.36-41
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• 1998

Objective of the research is to deteonine the praeLic따 running parameters for neutralization and removal of heavy metals from plating wastewater with waste-oyster shells by the Bohart$.$Adams equation. Waste-oyster shells discharged from the d domestic oyster cultnring fields cause a serious ocean environmental pollution. However, it is expected that those are able to b be recycled for removal of heavy metals through neutralization of plating wastewater because the shells contain approximate 93% $CaCO_3$, and have multi-pore voids. By applying the results of the continuous experiments to Bohart-Adams equation, s service time decreases in the order of Cr>Fe>Cu while removal efficiencies of metals become less in the order of Fe>Cr>Cu.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.3
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• pp.200-205
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• 2013

The separation of hydrogen depends on porosity, diffusivity and solubility in permeation membrane. Dense membrane is always showing a solution diffusion mechanism but porous membrane is not showing. Therefore, porous membrane has a good hydrogen flux due to pore is carried out transferred media. This mechanism is named as the Knudsen diffusion. Hydrogen molecules or hydrogen atoms are diffused along pore that is a mean free path. In this study, complex layer hydrogen permeation membrane was fabricated by hot press process. And then, it was evaluated and calculated to relationship between hydrogen permeability and membrane porosity.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.8
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• pp.8-15
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• 2007

In this paper, we fabricated the field emitter display using oxidized porous polysilicon(OPPS). Their field emission characteristics and the brightness were investigated for each pixel. The OPPS emitter was operated to each pixel using passive matrix for application of large panel display. We set up the proper thickness and width of upper electrode. The fine structure of OPPS was analyzed and the field emission characteristics of each pixel were investigated. As a result of field emission characteristics of different upper electrode thickness and width, we confirmed that the most efficient thickness was 2nm/7nm and increased the emission efficiency over the width of 2.5 mm. Even if field emission characteristics of each pixel was a little different but we confirmed the same leakage current and emission current, emission efficiency at each pixel. The leakage current and emission current was decreased according to the time increases but all of each pixel were uniformly decreased. We confirmed that the brightness of each pixel was not different and the brightness of OPPS field emitter was 700 cd/m2 at the Vps=20 V. Accordingly, the patterned OPPS field emitter can be applied to high quality field emission display devices.