• 마이크로전자및패키징학회지
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• 제23권4호
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• pp.57-61
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• 2016

대용량 전력저장용 황화나트륨 기반의 전지를 개발함에 있어서 베타 알루미나 고체 전해질 튜브와 알파 알루미나 셀 캡 간의 물리적 접합을 위해서는 세라믹-세라믹 접합용 씰링 글라스 후막 페이스트가 필요하다. 본고에서는 글라스 프릿 분말의 입도, 열처리 조건이 씰링 글라스의 열처리 후 미세구조 특히 기공율과 그 분포에 미치는 영향을 연구하였다. 씰링 글라스 분말의 입자가 클수록 열처리 후의 글라스의 미세 조직상에서의 기공율 및 기공의 수가 감소하였으며, 열처리 온도가 증가 할수록 기공의 수가 감소하는 반면 기공의 크기는 증가함을 확인하였다. 이로써 글라스 씰란트의 제조에 있어서, 글라스 페이스트용 글라스 프릿 분말의 입자 크기와 씰링 열처리 온도의 적절한 선정에 의해 글라스 씰링부의 미세구조에서 기공율과 기공의 분포 및 기공의 수를 제어할 수 있음을 보여주었다.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.447-452
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• 2013

In this study we report a new method for the synthesis of a silica monolithic column bed with bimodal pores (throughpores and mesopores). The template induced synthesis method was used to direct bimodal pores simultaneously instead of the usual post base-treating method. Block polymer Pluronic F127 was chosen as a dual-function template to form hierarchically porous silica monolith with both macropores and mesopores. This is a simplification of the method of monolithic column preparation. Poly(ethylene glycol) was used as a partial substitute for F127 can effectively prevent shrinkage during the monolith aging process without losing much surface area (944 $m^2/g$ to 807 $m^2/g$). More importantly, the resultant material showed a much narrower mesopore size (centered at 6 nm) distribution than that made using only F127 as the template reagent, which helps the mass transfer process. The solvent washing method was used to remove the remaining organic template, and it was proved to be effective enough. The new synthesis method makes the fabrication of the silica monolithic column (especially capillary column) much easier. All the structure parameters indicate that monolith PFA05 prepared by the above method is a good material for separation, with the merits of much higher surface area than usual commercial HPLC silica particles, suitable mesopore volume, narrow mesopore size distribution, low shrinkage and it is easily prepared.

• 분석과학
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• 제19권3호
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• pp.211-217
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• 2006

Diphenyl amine (DPA) was polymerized inside the channels of the mesoporous silica (MCM-41). MCM-41 (C) and MCM-41 (D) were prepared with cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB), respectively and used as hosts. Initially, the self assembly of DPA inside the pores of MCM-41 was made in ${\beta}$-naphthalene sulfonic acid (NSA) medium and subsequently poly (diphenylamine), PDPA was formed by oxidative polymerization. $N_2$ adsorption-desorption measurements of PDPA loaded MCM-41 (C) and MCM-41 (D) show variations in pore volume and surface area between them. A tubular form of poly (diphenylamine), PDPA was envisaged to form in the pores of MCM-41 and supported by high resolution transmission microscopy. The presence of PDPA inside the channel of MCM-41 was further confirmed by FTIR spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction.

• 자원리싸이클링
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• 제26권6호
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• pp.97-101
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• 2017

메탈폼은 매우 많은 기공을 포함하는 세포상 구조를 갖는 고체금속을 일컫는다. 특히 관통 기공 같은 개기공들은 고온용 필터 및 촉매 지지체 등으로 산업적으로 많이 사용되고 있다. 본 연구에서는 슬러리 코팅공정으로 90% 이상의 기공율과 2 mm 이상의 기공크기를 갖는 Fe 폼을 제조하였다. 이때 Fe 분말과 $Fe_2O_3$ 분말의 혼합비를 달리하여 기공율과 기공크기를 제어하였다. 이를 위해 우선 분말, 증류수 및 폴리비닐알콜(PVA)를 균일하게 혼합하여 슬러리를 제조하였다. $Fe_2O_3$ 분말의 혼합 비율이 증가할수록 PU 폼에 코팅된 슬러리의 양이 증가한 반면 Fe 폼의 수축 및 기공율은 각각 감소하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권5호
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• pp.45-52
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• 2014

Torrefaction and hydrothermal carbonization (HTC) are productive methods to reclaim energy from lignocellulosic biomass. The hydrophobic, homogenized, energy dense and carbon rich solid fuel can be obtain from torrefaction and hydrothermal carbonization. Dead leaves were carbonized in a stainless steel reactor of volume 200 ml with torrefaction ($250-270^{\circ}C$) for 120 minutes and hydrothermal carbonization ($200-250^{\circ}C$) for 30 minutes, with mass yield solid fuel ranging from 57-70% and energy content from 16.81MJ/kg to 22.01 MJ/kg compare to the biomass. The char produced from torrefaction process possess high energy content than hydrothermal carbonization. The highest energy yield of 89.96% was obtained by torrefaction at $250^{\circ}C$. The energy densification ratio fluctuated in between 1.15 to 1.30. On the basis of pore size distribution of the chars, the definition of the International Union of Pure and Applied Chemistry (IUPAC) was used as a classification standard. The pore diameter was ranging within 11.09-19 nm which play important role in water holding capacity in soil. Larger pores can hold water and provide passage for small pores. Therefore, it can be concluded that high pore size char can be obtained my HTC process and high energy content char of 22.01 MJ/Kg with 34.04% increase in energy can be obtain by torrefaction process.

• Carbon letters
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• 제10권3호
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• pp.181-189
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• 2009

Activated carbon spheres (ACS) were prepared at different heating rates by carbonization of the resole-type phenolic beads (PB) at $950^{\circ}C$ in $N_2$ atmosphere followed by activation of the resultant char at different temperatures for 5 h in $CO_2$ atmosphere. Influence of heating rate on porosity and temperature on carbon structure and porosity of ACS were investigated. Effect of heating rate and temperature on porosity of ACS was also studied from adsorption isotherms of nitrogen at 77 K using BET method. The results revealed that ACS have exhibited a BET surface area and pore volume greater than $2260\;m^2/g$ and $1.63\;cm^3/g$ respectively. The structural characteristics variation of ACS with different temperature was studied using Raman spectroscopy. The results exhibited that amount of disorganized carbon affects both the pore structure and adsorption properties of ACS. ACS were also evaluated for structural information using Fourier Transform Infrared (FTIR) Spectroscopy. ACS were evaluated for chemical composition using CHNS analysis. The ACS prepared different temperatures became more carbonaceous material compared to carbonized material. ACS have possessed well-developed pores structure which were verified by Scanning Electron Microscopy (SEM). SEM micrographs also exhibited that ACS have possessed well-developed micro- and meso-pores structure and the pore size of ACS increased with increasing activation temperature.

• 대한금속재료학회지
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• 제47권9호
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• pp.597-603
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• 2009

The hydrogen reduction behavior of ultrasonic ball-milled $WO_3-CuO$ nanopowder, which is highly related with micro-pore structure, was investigated by thermogravimetry(TG) and hygrometry system. EDS and TEM results represented that the ultrasonic ball-milled $WO_3-CuO$ nanopowder consisted of the agglomerates which was confirmed as a homogeneous mixture of $WO_3$ and CuO particles. It was found that the reduction reaction of CuO was retarded by initial micro-pores which are smaller than 40 nm in the ultrasonic ball-milled $WO_3-CuO$ nanopowder. The earlier agglomeration of Cu particles at comparably low temperature decreased the volume of micro-pores in the $WO_3-CuO$ nanopowder which caused the retardation of $WO_3$ reduction reaction. These results clearly explain that the micro-pore structure significantly affected the reduction reaction of $WO_3$ and CuO in the $WO_3-CuO$ nanopowder.

• 대한기계학회논문집A
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• 제38권5호
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• pp.527-534
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• 2014

본 논문에서는 이미지 기반 전산 모형을 이용하여 섬유강화 복합재료의 기공 탄성 해석을 수행하였다. 먼저 다공성 기지에 대한 단면 이미지를 분석하여 기공도, 기공 개수, 기공 분포 등을 확인하였다. 이미지의 해상도, 위치, 크기에 따른 전산 모형화 및 유한요소 해석을 수행하였으며, 주요 결과로써 유효 탄성 계수, 기공 탄성 인자, 변형 에너지 밀도를 정량적으로 산출하였다. 기공 탄성 인자는 유효 탄성 계수와 기공 압력에 의한 팽창 변형도를 기준으로 계산하였다. 또한 이미지 기반 전산 모형을 이용한 기공 탄성 해석 결과의 신뢰성 확인을 위해, 기공의 형상 및 배열을 단순화시킨 대표 체적 요소 모형의 해석 결과와 비교하였다.

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 춘계 총회 및 학술발표회
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• pp.11-15
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• 1995

Polysulfone (PS) membranes were prepared by the phase inversion process using water or isopropanol as nonsolvent. The Flory-Huggins theory for a ternary system nonsolvent/solvent/polymer is applied to describe the thermodynamic equilibria of the components. The calculated ternary phase equilibria show that demixing of a PS binary solution with n-methylpyrrolidone (NMP) will be fast in a water coagulation bath and will be delayed in an isopropanol bath. The prepared membranes were characterized by SEM, gas adsorption-desorption measurement, and permeability test. The membrane, which is precipitated by fast demixing in a water bath, has nodular structures in the skin region and includes finger-like cavities in the sublayer. The membrane coagulated by isopropanol has a very dense and thick skin structure, which is formed by delayed demixing. The membrane coagulated by isopropanol showed considerably lower pore volume and surface area compared to that observed with water coagulation method. With dimethylformamide (DMF) as solvent and 2-3 wt% of water, the solution can show the liquid-liquid phase separation due to agglomation of the polymer-lean phase from the homogeneous solution. The membranes, which were coagulated near an equilibrium state, show the large (micron size) round pores in the whole membranes. The pores do not contribute the permeation characteristics.

• 대한화학회지
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• 제28권3호
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• pp.194-202
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• 1984

陽이온 交換한 天然제올라이트에 依한 有機黃化合物의 液相吸着特性을 考察하였다. 平衡吸着量은 天然제올라이트의 交換한 陽이온과 吸着質인 有機黃化合物의 構造에 影響을 받고 있음을 알 수 있었다. 또한 平衡吸着量은 메르캅탄(mercaptane), 설파이드(sulfide), 디설파이드(disulfide), 치오펜(thiopen) 順으로 減小하였으며, 치오펜 誘導體의 경우는 ${\pi}$ 電子가 많아짐에 따라 吸着能은 교환 이온의 polarizing power에 比例하였다. 吸着速度로부터 有機黃化合物의 吸着은 pore 내의 擴散이 律速段階임을 알수 있었고, 水分과 같은 작은 吸着質은 micro pore에 吸着이 일어나는 反面, 有機黃化合物은 transitional-pore에 吸着이 일어났다.