• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.34-34
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• 2003

산업의 발달로 인하여 자원재활용의 문제와 환경 오염 방지와 더불어 에너지 절약에 대한 중요성이 확대되면서 분리 고정을 이용한 환경 오염 방지 및 에너지 절약에 대한 관심이 확대되었다. 세라믹 필터는 열악한 환경에서의 적용 그리고 에너지 소모가 적은 장점을 가지고 있다. 여러종류의 재료들 중에서 기공의 제어가 용이한 알루미나 여과막은 보에하미트(${\gamma}$-AlOOH) 분말과 금속 알콕사이드(ATSB, aluminum tri-sec butoxide)를 사용하여 간단하게 제조할 수 있다. 알루미나는 열처리 론도에 따라 $\alpha$-A1$_2$O$_3$ 결정상 뿐만 아니라 몇 가지 준안정한 결정구조를 가진다. 보에마이트(${\gamma}$-AlOOH)는 45$0^{\circ}C$ 근처에서 미세한 기공을 가진 ${\gamma}$-A1$_2$O$_3$로 상전이 되는 것으로 알려져 있고, 120$0^{\circ}C$보다 낮은 온도에서 열처리하게 되면 미세구조의 변화는 일어나지 않고 약간의 입자 성장만을 수반하는 $\delta$-A1$_2$O$_3$ 또는 $\theta$-A1$_2$O$_3$으로 상전이가 일어난다. $\alpha$-A1$_2$O$_3$로의 상전이는 기공 크기의 변화와 vermicular구조를 가지는 비정상적인 입자성장을 수반하게 된다. 여과막은 기공크기와 분포를 제어하는 것이 매우 중요하므로, 상전이와 미세구조의 변화를 이해하는 것은 중요하다.

• 한국전기화학회:학술대회논문집
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• 2003.10a
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• pp.73-73
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• 2003

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.2
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• pp.51-54
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• 2022

The physical properties of the noble metal current-collector used for fuel cells are greatly influenced by the material porosity. Therefore, increasing the porosity of the material studies has attracted much attention. One of the most representative strategies is to use porosity additives in sintering materials. The conventional porosity additive had a threedimensional structure of a spherical powder. In this study, porosity additive with 2-dimensional (2D) nanosheet was used to decrease the sintering density of Ag current-collector and its effect was confirmed. As a 2D layered structure material, 1 nm-thick RuO₂ nanosheets were used as porosity additives.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.3
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• pp.13-18
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• 2017

Water glass is much cheaper than silicon alkoxide, so it has advantage for commercialization. A condensation by acid catalyst makes considerable effect about the properties of water glass based silica aerogel among many factors in silica aerogel process. The pore structural properties of water glass based silica aerogel such as specific surface area and pore size distribution have been investigated through the changes in the amount and the kinds of acid catalyst. It has been confirmed that water glass based silica aerogel is affected by various conditions of catalyst in the condensation reaction such as the kind, concentration, and the amount of mole of acid catalyst on the properties of final products. Especially, it is checked that the effect of mole of acid is more prominent than that of concentration. In the case for conventional method with introducing 4M HCl in condensation step, the silica aerogel could be synthesized which has $394m^2/g$ of specific surface area, 2.20 cc/g of pore volume, 22.3 nm of average pore size, and 92.53% of porosity. On the other hand, when 4M sulfuric acid was used with 73 mmol at the condensation step of water glass based silica aerogel, the pore structural characteristics of water based silica aerogel showed better properties than the case of using HCl, for example, specific surface area was measured as $516m^2/g$, and pore volume, average pore diameter, and porosity were obtained as 3.10 cc/g, 24.1 nm, and 96.1%, respectively.

• Korean Chemical Engineering Research
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• v.45 no.6
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• pp.591-595
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• 2007

The membrane filter coated with nanostructured porous surface layer was made by heat treatment after depositing nanoparticles onto a conventional micron-fibrous metal filter as a substrate filter. The nanostructured porous layer membrane filter (NSPL-MF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by coating the nanoparticle agglomerates of dendrite structure onto the micron-fibrous metal filter. Pressure drop of nanostructured porous layer membrane filter decreased with increasing the heat treatment temperature to make the nanostructured porous layer adhered on the filter surface because the nanoparticle agglomerates shrank, but filtration efficiency did not decrease clearly.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.489-492
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• 1998

흡착 기능을 가지는 소재로서 오래 전부터 사용되어 온 활성탄소는 최근 환경에 대한 관심이 고조되면서 새삼 주목의 대상이 되고 있는 소재이다. 제품의 형태는 사용 목적에 따라 다르지만 보편화 된 것은 주로 입상 및 분말 상이다. 하지만 이러한 형태는 비표면적이 작고 기공분포가 넓은 단점 때문에 미세 오염물의 제거에는 부적합한 면이 있다[1]. (중략)

• Journal of Environmental Science International
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• v.5 no.5
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• pp.593-603
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• 1996

A dual-porosity filmed agglomerate model for the porous cathode of the molten carbonate fuel has been investigated to predict the cell performance. A phenomenological treatment of molecular, kinetic and electrode parameters has been given. The major physical and chemical phenomena being modeled include mass transfer, ohmic losses and reaction kinetics at the electrode- electrolyte interface. The model predicts steady-state cell performance, given the above conditions that characterize the state of the electrode. Quasi-linearization and finite difference techniques are used to solve the coupled nonlinear differential equations. Also, the effective surface area of electrode pore was obtained by mercury porosimeter. The results of the investigation are presented in the form of plots of overpotential vs. current density with varied the electrode material, gas composition and mechanism. The predicted polarization curves are compared with the empirical data from 1 c$m^2$ cell. A fair correspondence is observed.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.64-70
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• 1998

Porous body was prepared from coal fly ash 70 wt%0clay 30 wt% slip using DCC(Direct Coagulated Casting) method. Effect of the specific gravity of the slip on the pore size and distribution of the sintered body was examined by the SEM observation of microstructure and mercury porosimetry measurement of the pore size distribution. Average pore size of the porous sintered body was about 2.5μm for all slips with specific gravity of 1.55, 1.60 and 1.65g/cm3, respectively. Sintered body prepared from the slip of specific gravity of 1.60g/cm3 have the narrowest pore size distribution. slip of specific gravity of 1.55g/cm3 shows broader pore size distribution due to slow gellation process. Slip of specific gravity of 1.65g/cm3 required large amount of deflocculant and showed large variation of the viscosity with addition of coagulant which resulted in very unstable slip properties.

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1078-1083
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• 2000

정전안정화 및 입체안정화를 동시에 적용한 복합안정화기구에 의하여 25 부피%의 나노 $Al_2$O$_3$슬러리를 제조하고, 이로부터 얻은 주입성형체, 원심성형체, 진공성형체의 기공구조 분석을 통하여 입자충전거동을 살펴보았다. 나노 알루미나 분말의 습식 성형체의 충전구조는 성형방법에 의하여 가해지는 외력의 영향을 크게 받지만, 반발력을 제공하는 표면장벽층의 상호작용에 의해서도 현저한 차이를 보이는 것으로 나타났다. 예비소결실험을 통하여 나노분말에서도 기공크기가 작고, 크기분포가 좁으며, 높은 밀도를 가진 균일성형체의 미세구조가 소결미세구조를 균일하게 하는데 필수적인 조건임을 확인하였다.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.57-61
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• 2016

Thick film sealing glass paste is required for cell packaging of NaS based battery for energy storage system, to join the beta-alumina electrolyte tube and the alpha-alumina battery cell cap components. This paper presents the effect of the particle sizes of seal glass powder and the sealing temperatures on the microstructure of the glass sealants was investigated. It was found that the larger in the particle size of seal glass powder, the smaller the pore volume and the number of pores in a unit area. Also, the number of pores decreased with increasing the sealing temperatures while the pore size was increased. This result enables the control of porosity, pore distribution and number of pores in a microstructure of glass sealing component by proper selection of glass powders particle size and sealing temperature.