PrBa0.9Sr0.1Co2O5+δ 세라믹 분리막의 제조 및 산소투과 특성

표대웅,김종표,손수환,박정훈 한국막학회 2011 멤브레인 Vol.21 No.4

PrBa0.9Sr0.1Co2O5+δ 조성의 산화물을 고상반응법을 이용하여 합성하였다. 합성된 분말은 압축 성형 후 1,250℃에서 소결하여 치밀한 세라믹 분리막을 제조하였다. 제조된 PrBa0.9Sr0.1Co2O5+δ분리막은 XRD분석 결과 이중 페롭스카이트 (double perovskite)구조를 보였다. 밀봉재료로는 pyrex ring을 사용하여 가스누출 실험 및 산소투과 분석을 하였다. 산소투과량 분석은 850~950℃범위에서 측정되었다. 산소투과실험 결과, 투과량은 온도증가에 따라 0.15에서 0.32mL/㎠·min로 증가하였다. PrBa0.9Sr0.1Co2O5+δ oxide was synthesized by soild state reaction method. Dense ceramic membrane was prepared using as-prepared powder by pressing and sintering at 1250℃. XRD result of membrane showed double perovskite structure. Leakage and oxygen permeation test were conducted on the membrane sealed by pyrex ring as a sealing material. Oxygen permeation was measured in the temperature range from 850 to 950℃. The oxygen flux of PrBa0.9Sr0.1Co2O5+δ membrane was increased with the temperature from 0.15 to 0.32mL/㎠·min.

YBaCo2O5+δ 세라믹 분리막의 산소투과 특성

표대웅,김종표,박정훈 한국막학회 2012 멤브레인 Vol.22 No.2

YBaCo2O5+δ oxide was synthesized by solid state reaction and a typical dense membrane has been prepared using as-prepared powder by unilateral pressing and sintering at 1,180℃. The YBaCo2O5+δ membraneswas analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD analysis showed the double layered perovskite structure was observed over 1,150℃ without impurities. Oxygen permeation was measured in the temperature range from 750 to 950℃ according to oxygen partial pressure difference between feed and permeation side. The oxygen permeation flux increased with increasing temperature and oxygen partial pressure and the maximum oxygen flux of YBaCo2O5+δ membrane with 1.0 mm thickness was about 0.15 mL/cm2·min at 950℃ and PO2 = 0.42 atm. The activation energy for oxygen permeation decreased with decreasing oxygen partial pressure to be 76.0 kJ/mol at the condition of PO2 = 0.21 atm. YBaCo2O5+δ조성의 산화물을 고상반응법을 이용하여 합성하였으며, 합성된 분말은 압축 성형 후 1,180℃에서 소결하여 치밀한 분리막을 제조하였다. YBaCo2O5+δ 분리막은 X-선 회절분석기(XRD)와 전자 주사 현미경(SEM)을 이용하여 분석하였다. XRD 분석결과 1,150℃ 이상에서 다른 불순물 없이 이중층 페롭스카이트 구조가 얻어졌다. 산소투과량은 분리막 양면에 산소분압 차이에 따라 750~950℃ 온도범위에서 측정하였다. 산소투과량은 온도와 산소분압이 증가할수록 증가하였고, 두께 1.0 mm의 YBaCo2O5+δ 분리막은 950℃, PO2 = 0.42 atm에서 약 0.15 mL/cm2·min의 최대 투과량을 보였다. 산소투과에 대한 활성화 에너지는 산소 분압이 감소할수록 감소하였고 PO2 = 0.21 atm의 조건에서 76.0 kJ/mol이었다.

$YBaCo_2O_{5+{\delta}}$ 세라믹 분리막의 산소투과 특성

표대웅,김종표,박정훈,Pyo, Dae-Woong,Kim, Jong-Pyo,Park, Jung-Hoon 한국막학회 2012 멤브레인 Vol.22 No.2

$YBaCo_2O_{5+{\delta}}$조성의 산화물을 고상반응법을 이용하여 합성하였으며, 합성된 분말은 압축 성형 후 $1,180^{\circ}C$에서 소결하여 치밀한 분리막을 제조하였다. $YBaCo_2O_{5+{\delta}}$ 분리막은 X-선 회절분석기(XRD)와 전자 주사 현미경(SEM)을 이용하여 분석하였다. XRD 분석결과 $1,150^{\circ}C$ 이상에서 다른 불순물 없이 이중층 페롭스카이트 구조가 얻어졌다. 산소투과량은 분리막 양면에 산소분압 차이에 따라 $750{\sim}950^{\circ}C$ 온도범위에서 측정하였다. 산소투과량은 온도와 산소분압이 증가할수록 증가하였고, 두께 1.0 mm의 $YBaCo_2O_{5+{\delta}}$ 분리막은 $950^{\circ}C$, $PO_2$ = 0.42 atm에서 약 0.15 mL/$cm^2{\cdot}min$의 최대 투과량을 보였다. 산소투과에 대한 활성화 에너지는 산소 분압이 감소할수록 감소하였고 $PO_2$ = 0.21 atm의 조건에서 76.0 kJ/mol이었다. $YBaCo_2O_{5+{\delta}}$ oxide was synthesized by solid state reaction and a typical dense membrane has been prepared using as-prepared powder by unilateral pressing and sintering at $1,180^{\circ}C$. The $YBaCo_2O_{5+{\delta}}$ membraneswas analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD analysis showed the double layered perovskite structure was observed over $1,150^{\circ}C$ without impurities. Oxygen permeation was measured in the temperature range from 750 to $950^{\circ}C$ according to oxygen partial pressure difference between feed and permeation side. The oxygen permeation flux increased with increasing temperature and oxygen partial pressure and the maximum oxygen flux of $YBaCo_2O_{5+{\delta}}$ membrane with 1.0 mm thickness was about 0.15 mL/$cm^2{\cdot}min$ at $950^{\circ}C$ and $PO_2$ = 0.42 atm. The activation energy for oxygen permeation decreased with decreasing oxygen partial pressure to be 76.0 kJ/mol at the condition of $PO_2$ = 0.21 atm.

$PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$ 세라믹 분리막의 제조 및 산소투과 특성

표대웅,김종표,손수환,박정훈,Pyo, Dae-Woong,Kim, Jong-Pyo,Son, Su-Hwan,Park, Jung-Hoon 한국막학회 2011 멤브레인 Vol.21 No.4

$PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$ 조성의 산화물을 고상반응법을 이용하여 합성하였다. 합성된 분말은 압축 성형 후 $1,250^{\circ}C$에서 소결하여 치밀한 세라믹 분리막을 제조하였다. 제조된 $PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$분리막은 XRD분석 결과 이중 페롭스카이트 (double perovskite)구조를 보였다. 밀봉재료로는 pyrex ring을 사용하여 가스누출 실험 및 산소투과 분석을 하였다. 산소투과량 분석은 $850{\sim}950^{\circ}C$범위에서 측정되었다. 산소투과실험 결과, 투과량은 온도증가에 따라 0.15에서 $0.32mL/cm^2{\cdot}min$로 증가하였다. $PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$ oxide was synthesized by soild state reaction method. Dense ceramic membrane was prepared using as-prepared powder by pressing and sintering at $1250^{\circ}C$. XRD result of membrane showed double perovskite structure. Leakage and oxygen permeation test were conducted on the membrane sealed by pyrex ring as a sealing material. Oxygen permeation was measured in the temperature range from 850 to $950^{\circ}C$. The oxygen flux of $PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$ membrane was increased with the temperature from 0.15 to $0.32mL/cm^2{\cdot}min$.

고온 열처리에 따른 PAN계 탄소섬유의 발열특성

표대웅 ( Dae Woong Pyo ),엄상용 ( Sang Yong Eom ),이영석 ( Young Seak Lee ),유승곤 ( Seung Kon Ryu ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.2

General purpose PAN-based carbon fibers were heat treated up to 1500℃, and analyzed their carbon contents, crstallinity, and crystalline size(Lc). Exothermic characteristics of carbon fiber were investigated in relation to crystallinity, and crystalline size(Lc). Carbon contents, crystallinities, and crystalline size(Lc) of PAN-based carbon fibers increased from 37.08 to 53.69%, and 1.62 to 1.82 nm, respectively as the increase of heat treatment temperature from 1000 ℃ to 1500 ℃. Initial surface temperature of fiber tow also 1inearly increased as the increase of crystallinity, and crystalline size(Lc). Therefore, the crystallinity and crystal size(Lc) of carbon fibers can indirectly and rapidly be estimated by measuring the surface temperature increase.

다공성의 $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$가 코팅된 $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 제조 및 투과 특성

김종표,표대웅,박정훈,이용택,Kim, Jong-Pyo,Pyo, Dae-Woong,Park, Jung-Hoon,Lee, Yong-Taek 한국막학회 2012 멤브레인 Vol.22 No.1

다공성 $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$로 코팅된 $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막은 압출성형 및 dip coating 방법으로 제조 되었다. 코팅된 관형 분리막의 특성은 X-선 회절분석기(XRD)와 전자 주사 현미경(SEM)을 이용하여 분석하였으며, 분석결과 $2{\mu}m$의 다공성 코팅 층을 갖는 페롭스카이트 구조임을 알 수 있었다. 산소투과량 분석은 $750{\sim}950^{\circ}C$ 범위에서 공급측과 투과 측을 대기 중 공기와 진공으로 하여 수행되었다. 다공성의 $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$로 코팅된 $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 산소투과량은 $950^{\circ}C$에서 $3.2mL/min{\cdot}cm^2$로 코팅되지 않은 분리막보다 높게 나타났으며, 11일 동안의 장기 안정성 실험결과 코팅 층에 의해 안정성이 증가됨을 알 수 있었다. Tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membranes with $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$ porous coating layer were prepared by extrusion and dip coating technique. XRD and SEM result showed the tubular membrane possessed the perovskite structure and porouscoating layer (thickness= about $2{\mu}m$) in surface. The oxygen permeation test was measured at condition of ambient air (feed side) and vacuum (permeate side) in the temperature range from 750 to $950^{\circ}C$. The oxygen permeation flux of $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ tubular membrane with $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$ porous coating layer reached maximum $3.2mL/min{\cdot}cm^2$ at $950^{\circ}C$ and was higher than non-coated $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ tubular membrane. Long-term stability test result indicated that the oxygen permeation flux was quite stable during the 11 day.

만성 증식성 캔디다증에서 hBD-2의 발현과 T 림프구 침윤에 관한 연구

윤대웅,조영아,김수진,윤혜정,홍성두,이재일,홍삼표 대한구강악안면병리학회 2012 대한구강악안면병리학회지 Vol.36 No.3

Chronic hyperplastic candidiasis (CHC) is characterized by epithelial hyperplasia of the oral mucosa associated with candidal hyphae. The immune status of host is one of the factors that induce clinically evident candidal infection. Host defense mechanisms include inflammatory cells, epithelial barrier, and antimicrobial peptides such as human beta 2 defensin (hBD-2). In the present study, we investigated the densities of CD4+/CD8+ T lymphocytes and hBD-2 expression of epithelial cells in CHC. Immunohistochemical staining was performed on 10 cases of CHC using CD4, CD8 and hBD-2. Ten specimens of chronic mucositis were selected for comparison, and went through the same examination. hBD-2 was expressed in the spinous cell layers and the keratin layers of 7 CHC patients, while the epithelium of chronic mucositis did not demonstrate the hBD-2 expression except for one case. Also, hBD-2 expression was stronger when the hyphae invaded the upper stratum spinosum (P =.019). However, the densities of CD8+ T lymphocytes were significantly lower in the CHC patients, suggesting that the ability of CD8+ T cells to enter the epithelium and target the pathogenic hyphae was decreased in CHC. Increased hBD-2 expression seemed to be significantly associated with the candidal infection, while not promoting the cell-mediated immune reaction in CHC.

만성 증식성 캔디다증에서 hBD-2의 발현과 T 림프구 침윤에 관한 연구

윤대웅,조영아,김수진,윤혜정,홍성두,이재일,홍삼표 대한구강악안면병리학회 2012 대한구강악안면병리학회지 Vol.36 No.3

Chronic hyperplastic candidiasis (CHC) is characterized by epithelial hyperplasia of the oral mucosa associated with candidal hyphae. The immune status of host is one of the factors that induce clinically evident candidal infection. Host defense mechanisms include inflammatory cells, epithelial barrier, and antimicrobial peptides such as human beta 2 defensin (hBD-2). In the present study, we investigated the densities of CD4+/CD8+ T lymphocytes and hBD-2 expression of epithelial cells in CHC. Immunohistochemical staining was performed on 10 cases of CHC using CD4, CD8 and hBD-2. Ten specimens of chronic mucositis were selected for comparison, and went through the same examination. hBD-2 was expressed in the spinous cell layers and the keratin layers of 7 CHC patients, while the epithelium of chronic mucositis did not demonstrate the hBD-2 expression except for one case. Also, hBD-2 expression was stronger when the hyphae invaded the upper stratum spinosum (P =.019). However, the densities of CD8+ T lymphocytes were significantly lower in the CHC patients, suggesting that the ability of CD8+ T cells to enter the epithelium and target the pathogenic hyphae was decreased in CHC. Increased hBD-2 expression seemed to be significantly associated with the candidal infection, while not promoting the cell-mediated immune reaction in CHC.