• Textile Coloration and Finishing
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• v.23 no.2
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• pp.107-117
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• 2011

Polyurethane (PU) was synthesized by one-shot process and the PU nanofiber was prepared by electrospinning. In this study, electrospun PU multi-membranes were prepared with various coating thickness ratio of base resin to top resin, where the base resin contains melamine curing agent and acid catalyst and the top resin contains water-repellent agent of fluoro-carbon compounds. The PU nanofiber multi-membranes were analyzed by field-emission scanning electron microscopy, differential scanning calorimeter, breathability, tensile strenth, air permeability and water resistance. The results showed that the PU multi-membrane provided excellent waterproof and moisture permeability.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.865-871
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• 2005

Submicron thick solid electrolyte membrane is essential to the implementation of low temperature solid oxide fuel cell, and, therefore, development of new electrode structures is necessary for the submicron thick solid electrolyte deposition while providing functions as current collector and fuel transport channel. In this research, a nickel membrane with multi-stage nano hole array has been produced via modified two step replication process. The obtained membrane has practical size of 12mm diameter and $50{\mu}m$ thickness. The multi-stage nature provides 20nm pores on one side and 200nm on the other side. The 20nm side provides catalyst layer and $30\~40\%$ planar porosity was measured. The successful deposition of submicron thick yttria stabilized zirconia membrane on the substrate shows the possibility of achieving a low temperature solid oxide fuel cell.

• Membrane Journal
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• v.6 no.4
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• pp.213-218
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• 1996

Cholesterol-containing monomeric surfactants were synthesized, and sonicated in water to form a vesicle solution. This vesicle solution was dried to construct a membrane which had a molecular multilayer structure. Using UV irradiation the surfactants in this membrane were polymerized and molecular weight was determined. Using a X-ray diffractomelet, the thickness of one layer and the regularity of the multilayer were measured.

• KSBB Journal
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• v.6 no.4
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• pp.379-383
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• 1991

Pervaporation can be successfully utilized to recover alcohol from fermentation broths and dilute process streams. Polydimethylsiloxane (thickness: $60\mu$m), such as hydrophobic membrane have been employed in this application to produce an enriched product. The fermented alcohol was continuously extracted, and simultaneously concentrated by pervaporation, from the membrane bioreactor, and the extracted alcohol concentration was 6 to 10 times higher than in the broth. This experimental conditions were 6-10 Torr vacuum line, pH=5, $32^{\circ}C$, 3.5 liters of working volume, 200rpm of agitator speed, and 0.14 wm aeration flow rate.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.25-28
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• 2003

Low cost composite metallic membranes for the hydrogen separation and production have been prepared by using thin Pd-Ag foils reinforced by metallic (stainless steel and nickel) structures. Especially, “supported membranes” have been obtained by a diffusion welding procedure in which Pd-Ag thin foils have been joined with perforated metals (nickel) and expanded metals (stainless steel): in these membranes the thin palladium foil assures both the high hydrogen permeability and the perm-selectivity while the metallic support provides the mechanical strength. A second studied method of producing "laminated membranes" consists of coating non-noble metal sheets with very thin palladium layers by diffusion welding and cold-rolling. Palladium thin coatings over these metals reduce the activation energy of the hydrogen adsorption process and make them permeable to the hydrogen. In this case, the dense non-noble metal has been used as a support structure of the thin Pd-Ag layers coated over its surfaces: a proper thickness of the metal assures the mechanical strength, the absence of defects (cracks, micro-holes) and the complete hydrogen selectivity of the membrane. membrane.

• Journal of Pharmaceutical Investigation
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• v.23 no.4
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• pp.207-211
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• 1993

Reservoir type devices were designed for long-term implantable drug delivery system. The reservoir type device was prepared with the polymethacrylic acid gel coated with polyurethane membrane. Release controlling agent (RCA) were employed to control drug release from devices via generation of micropores in the membranes. The polyurethane membrane functioned as a rate controlling barrier. The drug release pattern of hydrogel demonstrated zero order kinetics. The release rate of drugs could be regulated by varying hydrophobicity/hydrophilicity and content of the RCA, as well as the thickness of the polyurethane membrane. The release of drugs from this system was governed by pore mechanism via simple diffusion and osmotic pressure.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.791-803
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• 2007

The purpose of this study was to evaluate exophytically vertical bone formation in residual ridge of the beagle dog by the concept of guided bone regeneration with a titanium reinforced e-PTFE membrane combined with irradiated cancellous human bone. Twelve male beagle dogs(mean age 1.5 years and mean weight 12kg) were used for this study. The alveolar ridges after extraction of all mandibular premolars were surgically and horizontally removed. At 8 weeks after extractions, full-thickness flap was reflected and cortical bone was removed with round bur and copious irrigation. Rectangular parallelepiped(10mm in length, 5mm in width, and 4mm in height) bended with titanium-reinforced e-PTFE(TR e-PTFE) membrane was placed on the decorticated alveolar ridge, fixed with metal pins and covered with full-thickness flap and assigned as a control group. Test groups ere treated with TR e-PTFE membrane filled with irradiated cancellous human bone. Of twelve beagle dogs, four control dogs and four test dogs without membrane exposure to oral cavity were sacrificed at 8 and 16 weeks respectively. The surgical sites were dissected out, fixed in 4% buffered formaldehyde, dyed using a Villanueva staining technique, and processed for embedding in plastic resin. The cutting and grinding methods were routinely processed for histologic and histomophometric analyis of exophytic bone formation as well as statistical analysis. The results of this study were as follows: 1. Exophytic bone formation in the both of experimental groups was increased respectively after surgery from 23.40% at 8 weeks to 46.26% at 16 weeks in the control groups, from 40.23% at 8 weeks to 47.11% at 16 weeks in the test groups(p<0.05). 2. At 8 weeks after surgery, exophytic bone formation was made 40.23% in the test groups and 33.40% in the control groups. Exophytic bone formation was significantly made in the test group more than in the control group. At 16 weeks after surgery, exophytic bone formation was made 44.11% in the test groups and 46.26% in the control groups. Exophytic bone formation was made in the test groups more than in the control groups, but there was no statistically significant differences. 3. The membrane was fixed with metal pins to closely contact it to the bone surface. So, collapse and deviation of the membrane could be prevented and in growth of connective tissue also could be blocked from the periphery of the membrane. On the basis of these findings, wee suggest that intraoral experimental model for exophytic bone formation may be effective to evaluate the effect of bone graft material. And it indicates that combined use of membrane and ICB graft material is more effective than use of membrane only for exophytic bone formation.

• Journal of the Korean Ceramic Society
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• v.30 no.7
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• pp.589-597
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• 1993

The optimum sol solution for making alumina membrane was synthesized by using sol-gel method with aluminium isopropoxide. Two types of supports were made from the $\alpha$-Al2O3 powder. The porosities of supports could be controlled by the forming methods and the heat treatment conditions. After the support was coated with optimum sol solution and heat-treated at 50$0^{\circ}C$ for 1hour, the thickness of crack-free membrane could be controlled reproductively with dipping time.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.106-108
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• 1998

It has been proved by the study on nanofiltration with PVA dense membranes in our laboratory that the PVA is good material for the formation of chemically stable nanofiltration (NF) membranes. However, the PVA NF composite membranes prepared so far have rarely shown flux and rejection high enough for the commerciallyzation. The reasons for them would be the relatively thick thickness and improper crosslinking degree of the PVA active layers of the composite membranes. In this study, PVA composite membranes with improved nanofiltration properties have been prepared and characterized in terms of the morphology and permeation properties.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.781-784
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• 2005

Twenty four types of thermopile for micro spectrometer infrared sensors were fabricated on low-stress $Si_3N_4$ membranes with $1.2{\mu}m-thickness$ using MEMS technology. Poly-Si thin film with thickness of 3500 ${\AA}$ as the first thermocouple material, was deposited by LPCVD method. And aluminum thin film with thickness of 6000 ${\AA}$ as the second thermocouple material, was deposited by sputtering method. Thermopile were designed and fabricated for optimum conditions by five parameters of thermocouple numbers (16 ${\sim}$ 48), thermocouple line widths (10 ${\mu}m$ ${\sim}$ 25 ${\mu}m$), thermocouple lengths (100 ${\mu}m$ ${\sim}$ 500 ${\mu}m$), membrane areas ($1^2\;mm^2$ ${\sim}$ $2.5^2\;mm^2$) and junction areas (150 ${\mu}m^2$ ${\sim}$ 750 ${\mu}m^2$), respectively. Electromotive forces of fabricated thermopile were measured 1.1 mV ${\sim}$ 7.4 mV at $400^{\circ}C$. It was thought that measurement results could be used for thermopile infrared sensors optimum structure for micro spectrometers.