• Membrane and Water Treatment
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• v.6 no.3
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• pp.251-262
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• 2015

In this work the preparation and characterization of a membrane containing a uniform mesoporous Titanium oxide top layer on a porous stainless steel substrate has been studied. The 316 L stainless steel substrate was prepared by powder metallurgy technique and modified by soaking-rolling and fast drying method. The mesoporous titania membrane was fabricated via the sol-gel method. Morphological studies were performed on both supported and unsupported membranes using scanning electron microscope (SEM) and field emission scanning microscope (FESEM). The membranes were also characterized using X-ray diffraction (XRD) and $N_2$-adsorption / desorption measurement (BET analyses). It was revealed that a defect-free anatase membrane with a thickness of $1.6{\mu}m$ and 4.3 nm average pore size can be produced. In order to evaluate the performance of the supported membrane, single-gas permeation experiments were carried out at room temperature with nitrogen gas. The permeability coefficient of the fabricated membrane was $4{\times}10^{-8}\;lit\;s^{-1}\;Pa^{-1}\;cm^{-1}$.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.341-356
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• 1995

The purpose of this study was to evaluate the effect of demineralized freeze dried bone and demineralized bone gel with guided tissue regeneration treatment around titanium implants with dehisced bony defects and also evaluate space maintaining capacity of demineralized bone gel type and DFDB powder type under e-PTFE membrane. In 3 Beagle dogs, mandibular premolar was extracted and four peri-implant osteotomies were formed for dehiscence. After insertion of implants, the four peri-implant defects were treated as follows. 1) In control group. no graft material and barrier membrane were applied. 2) In experimental group.1, the site was covered only with the e-PTFE membrane. 3) In experimental group 2,received DFDB powder and covered by the e-PTFE membrane. 4) In experimental group 3, demineralized bone gel and e-PTFE membrane were used. By random selection, animals were sacrificed at 4, 8, 12 weeks. The block sectioned specimens were prepared for decalcified histologic evaluation(hematoxylin and eosin staining) and undecalcified histologic evahiation(Von Kossa's and toluidine blue staining) with light microscopy. The results of this study were as follows. 1) In control group, there was a little new bone formation and connective tissue was completely filled in the defect area. 2) Experimental group 1 showed lesser quantity of bone formation as compared to the bone grafted group. Thin vertical growth of new bone formation around implant fixture was shown. 3) Experimental group 2 showed thick bucco-lingual growth of new bone formation and grafted bone particles were almost resorbed in 12 week group. 4) In experimental group 3, most grafted bone particles were not resorbed in 12 week group and thick bucco-lingual bone formation was shown in dehisced defect base area. 5) There was no remarkable differences in space making capacity and new bone formation procedure between demineralized freeze-dried bone powder type and demineralized bone gel type.

• Membrane Journal
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• v.16 no.3
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• pp.188-195
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• 2006

The purpose of this study was to investigate the effect of an intermittent aeration mode to reduce the membrane fouling in a submerged membrane process using the specifically devised module (YEF 750D-2). The fluid velocity on the module increased with increasing the supplied air volume, and decreased with the increment of MLSS in the biological reactor. The reduction rate of the fluid velocity was found to be $3\times10^{-4}m{\cdot}min/sec{\cdot}L$ per 1,000 mg MLSS/L increased. In the operation of the intermittent aeration, the intermitted stop of the aeration provoked the formation of a cake layer on the gel layer which was previously formed during the aeration, resulting in the highly increased TMP level. However, the TMP level could be significantly lowered by the subsequent backwashing and aeration that effectively removed the cake along with the gel layer on the membrane surface. In this study, the optimum condition for the intermittent aeration was determined to be aeration for 20 sec and pause for 20 sec.

• Macromolecular Research
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• v.14 no.4
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• pp.430-437
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• 2006

The ultra-drawing process of an ultra high molecular weight polyethylene (UHMWPE) gel film was examined by incorporating linear low-density polyethylene (LLDPE) and $BaTiO_3$ nanoparticles. The effects of LLDPE and the draw ratios on the morphological development and mechanical properties of the nanocomposite membrane systems were investigated. By incorporating $BaTiO_3$ nanoparticles in the UHMWPE/LLDPE blend systems, the ultra-drawing process provided a highly extended, fibril structure of UHMWPE chains to form highly porous, composite membranes with well-dispersed nanoparticles. The ultra-drawing process of UHMWPE/LLDPE dry-gel films desirably dispersed the highly loaded $BaTiO_3$ nanoparticles in the porous membrane, which could be used to form multi-layered structures for electronic applications in various embedded, printed circuit board (PCB) systems.

• BMB Reports
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• v.28 no.6
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• pp.504-508
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• 1995

The electrophoretic patterns of plasma membrane surface proteins of normal rat liver cells and rat hepatomas were compared in 10% non-denaturing and 7-15% gradient non-denaturing gel. Chemical carcinogens, 2-Me DAB (2-methyl-4-dimethylaminoazobenzene) and DENA (diethylnitrosamine), were used to induce hepatoma in rats. One protein which disappeared in hepatoma was identified in normal rat liver by non-denaturing gel electrophoresis. Rabbit antisera were raised against this specific protein, and the protein was purified by Sephacryl S-200 column and immunoaffinity chromatography using the purified antibody. The purified protein showed two bands of molecular weights approximately 50 $kD_{\alpha}$ and 52 $kD_{\alpha}$ by SDS-polyacrylamide gel electrophoresis, which reacted specifically with the antibody. However only one band was observed in non-denaturing gel and also in isoelectric focusing with a pI value of 6.6. This study showed the existence of an unique protein on the plasma membrane surface of normal rat liver cells which disappeared in rat hepatomas induced by chemical carcinogens.

• Journal of the Korean Ceramic Society
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• v.29 no.2
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• pp.107-118
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• 1992

Alumina supports for TiO2 ultrafiltration membrane coating were prepared by presintering disk-type preforms at 140$0^{\circ}C$. These supports showed uniform microstructures which had the apparent porosity of 40%, the pore size distribution in the range of 0.1~0.5${\mu}{\textrm}{m}$, and the water flux of 1400ι/$m^2$.h at the pressure difference of 10 atm. The optimum pH and concentration of the TiO2 sol for coating were 0.8 and 1.0 wt%, respectively, and sol particles were identified as rutile forms of 20 nm size. Crack-free alumina-supported rutile TiO2 membranes could be prepared through well controlled drying and heating the gel layer coated by the sol-gel dipping. The pore size of the TiO2 membranes heat-treated at 50$0^{\circ}C$ for 2 hrs was 30~80$\AA$, and their thickness varied from 1.1 to 3.8 ${\mu}{\textrm}{m}$ in accordence with the dipping time (4~40 min). The flux of water through this composite membrane at 10 atm was found to be in the range from 800 to 1100ι/$m^2$.hr depending on the dipping time (10~40 min). The membrane thickness increased linearly with the square root of the dipping time and the slope was 0.62 ${\mu}{\textrm}{m}$/{{{{ SQRT { min} }}.

• Membrane Journal
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• v.21 no.3
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• pp.229-235
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• 2011

In this study, mesoporous titania/alumina membranes were prepared by sol-gel method. Pore structure and phase composition of titania/alumina membranes could be changed by calcination temperature. The addition of alumina into titania membranes retarded anatase-to-rutile phase transformation, resulting in stabilization of pore structures. The 5 time dip-coated membrane calcined at $450^{\circ}C$ is about $10.3{\mu}m$ in thickness with an average pore size of 5 nm. Hydrogen and nitrogen permeances through the membrane were $17.1{\times}10^{-7}mol/m^2{\cdot}s{\cdot}Pa$ and $4.7{\times}10^{-7}mol/m^2{\cdot}s{\cdot}Pa$, respectively. These data were explained by the Knudsen diffusion mechanism.

• The Korean Journal of Zoology
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• v.35 no.3
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• pp.322-331
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• 1992

To investigate the svnthyesis of muscle proteins during differentiation of chicken myoblast, cvtosolic and membrane fractions were used for both sodium dodecvl sulfate polvcrylamide gel eBectrophoresis and two-dimensional gel electrophoresis. An extensive cell fusion was observed in 4 day culture. In the protein pattern of the cvtosolic fraction from SDS-PAGE. several protein bands including 250 kDa and 46 kDa showed remarkable changes during culture. the protein of 46 kDa was the most prominent one ann its optical density was the highest in 5 day culture (OD = 1.30). In the membrane fraction, band of 19.8 kDa showed the highest absorbance with 0.93 OD at 12 hr after initial plating and decreased gradually thereafter to 0.23 in 5 nay culture. From the results of two-dimensional gel electrophoresis of cytosolic fraction, the 46 kDa spot was observed as ko separated forms from culture 2 nary culture, and the sixte of this spot was the largest in 5 nay culture. In the pattern of membrane protein, the extensive appearance of newiv synthesized Proteins was found in a naut culture, but no Prominent spot was observed throughout culture. From the results of the present clay, we found that, during myoblast differentiation, the most prominent proteins were bands of 46 kDa and 19.8 kDa in cvtosolic and membrane fraction, respectively, and the appearance of new proteins was initiated at 48 hr after initial plating, and the 46 kDa protein was predominant in the cytoplasm of late culture in which extensive cell fusion was observed.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.37-40
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• 2003

Mesoporous zeolite - heteropolyacid-polymer hybrid membrane was prepared by sol-gel processes to make a proton conducting membrane. The crystallinity of mesoporous zeolite in composite membrane was increased with contents of heteropolyacid. Proton conductivity obtained from impedance measurements increases with contents of heteropolyacid, about 10$^{-3}$ S/cm in ca. 1.5 Wt% heteropolyacid.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.337-343
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• 2014

A single layer ultrafiltration(UF) ceramic membrane was prepared using boehmite sol. Boehmite was synthesized using a typical sol-gel process with optimization of the viscosity, pH, molar ratio of aluminum isopropoxide(AIP) and $HNO_3$. Boehmite sol was coated on a microfiltration(MF) support using the dip-coating method. MF support was dipped into the boehmite sol with a withdrawal speed of 5 mm/s and was maintained for 10 s in the boehmite sol, resulting in a uniform UF membrane layer of $10{\mu}m$ thickness. The porosity of the obtained membrane was measured and found to be 41.2%; the pore size was found to range from 80~100 nm, corresponding to the pore size of the UF membrane. The flux of the obtained membrane was initially 540 $L/m^2h$ and approximately 85% of the initial flux was recovered using a periodic back-flushing process.