• 한국결정성장학회지
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• 제33권2호
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• pp.71-77
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• 2023

흡수성 치주조직 재생유도재(국내 4개, 국외 2개) 총 6개 제품을 비교 연구하였다. 이종소재 차폐막의 경우, 콜라겐 제품은 우수한 기계적 강도를 보였으나 연신율이 작았다. 돼지심막은 우수한 기계적 물성에도 불구하고 두꺼운 두께로 사용에 제약이 되었다. 전기방사법으로 제조한 독일 PLLA/콜라겐 하이브리드형 복합 차폐막은 강도값과 흡수도는 낮았지만, 합성 및 천연고분자를 적절히 혼합함으로써 원하는 특성의 기계적 물성과 생체적합성 구현이 가능하였다. 본 연구에서 DA02(PLLA/젤라틴) 하이브리드형 복합고분자 소재는 기계적 물성과 생체적합성이 적절하여 100 % 수입에 의존하는 하이브리드형 흡수성 치주조직 재생 차폐막에 적용이 가능하였다.

• 한국전기전자재료학회논문지
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• 제28권6호
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• pp.384-389
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• 2015

In this paper, we fabricated ceramic body and sapphire wafer in order to develop a hydraulic pressure sensor with high sensitivity and high temperature stability. The sapphire wafer was adopted with a membrane of capacitance ceramic pressure sensor. The capacitance value of the sensor for the finite element analysis(FEM) showed a linear pressure characteristics. Membrane was processed with a diameter of 32.4 mm and a thickness of 1 mm by using alumina powders. Ceramic body was processed with a diameter 32.4 mm and a thickness 5 mm. The capacitance pressure sensor was made with high heat treatment of the ceramic body and the sapphire wafer. Initially capacitance of the pressure sensor was 50 pF and a capacitance of 110 pF was measured from 5 bar pressure. Output voltage of 5 V was appeared at 5 bar pressure.

• 한국세라믹학회지
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• 제35권4호
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• pp.355-363
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• 1998

The oxygen flux of SDC ($Sm_2O_3\;doped\;CeO_2$) solid electrolyte membranes with electronic and oxygen ion-ic conductivities has been investigated as a basic research in order to develop the conversion process of na-tural gas to syngas using the ceramic membrane reactor. Tube type membranes(1 mm thickness) were fa-bricated by slip casting of SDC powders prepared by the oxalate coprecipitaion method. Dense oxygen per-meation membranes(0.1 mm thickness) could be synthesized via sintering at $1450^{\circ}C$ for 2h and their re-lative density was over 95% The oxygen flux through SDC membranes doped 20mol% $Sm_15$ was about $1.13{\times}10^{-5}\;mol/m_2{\cdot}sec$ at low temperature around $800^{\circ}C$. In addition the SDC membranes showed a good thermaal stability for a long period of service.

• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.8-18
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• 2012

This paper presents a three-dimensional, transient cold-start polymer electrolyte fuel cell (PEFC) model to numerically evaluate the effects of membrane electrode assembly (MEA) design and cell location in a PEFC stack on PEFC cold start behaviors. The cold-start simulations show that the end cell experiences significant heat loss to the sub-freezing ambient and thus finally cold-start failure due to considerable ice filling in the cathode catalyst layer. On the other hand, the middle cells in the stack successfully start from $-30^{\circ}C$ sub-freezing temperature due to rapid cell temperature rise owing to the efficient use of waste heat generated during the cold-start. In addition, the simulation results clearly indicate that the cathode catalyst layer (CL) composition and thickness have an substantial influence on PEFC cold-start behaviors while membrane thickness has limited effect mainly due to inefficient water absorption and transport capability at subzero temperatures.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.684-687
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• 2004

A study was conducted to determine the effect of live weight of pheasants on egg production and egg quality characteristics. A total of 48 ring-necked pheasants were divided into control, heavy, middle and light BW groups. Live weights of the control were 1,187 g, 1,352.92 g for heavy group, 1,247.92 g for middle group and 1,003.33 g for light group. Egg production of groups were found as 47.32, 42.82, 45.79 and 46.51% respectively, in 10 weeks of period. There were no statistical differences on egg production among the groups. The effect of live weight on egg weight, shape index, specific gravity, shell weight, shell thickness, Haugh Unit, yolk weight and albumen weight were found statistically significant (p<0.05). The effect of live weight on albumen index, membrane weight and membrane thickness were found not important (p>0.05). On the other hand, other important factors to be effective on the egg quality of pheasants should be investigated. As a result of this study, live weight of pheasant hens is not an important factor to obtain high egg production in pheasants. But, body conformation of breeding materials should be in good conditions.

• Transactions on Electrical and Electronic Materials
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• 제17권4호
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• pp.189-195
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• 2016

Micro Hotplate (MHP) is the key component in micro-sensors, particularly gas sensors. Indeed, in metal oxide gas sensors MOX, micro-heater is used as a hotplate in order to control the temperature of the sensing layer which should be in the requisite temperature range over the heater area, so as to detect the resistive changes as a function of varying concentration of different gases. Hence, their design is a very important aspect. In this paper, we have presented the design and simulation results of a meander micro heater based on three different materials - platinum, titanium and tungsten. The dielectric membrane size is 1.4 mm × 1.6 mm with a thickness of 1.4 μm. Above the membrane, a meander heating film was deposed with a thickness of 100 nm. In order to optimize the geometry, a comparative study by simulating two different heater thicknesses, then two inter track widths has also been presented. Power consumption and temperature distribution were determined in the micro heater´s structure over a supply voltage of 5, 6, and 7 V.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.31-34
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• 1997

A new method for the prevention of foreign body-associated infections by controlled release of antibiotic was developed. The polyurethane (PU) matrix containing rifampicin was immobilized with hydrophilic photoreactive polyallylamine (PPA) containing azidophenyl groups. The rifampicin release characteristics and the long-lasting antimicrobial activities of the new material was compared with rifampicin-containing PU matrix without PPA membrane. The release rate of antibiotic from rifampicin-containing PU with PPA membrane significantly decreased as the thickness of PPA membrane was increased. The PPA-immobilized rifampicin-containing PU discs immersed in the PBS for 47 days had an efficient antimicrobial activity against both S. aureus and S. epidermidis.

• 멤브레인
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• 제1권1호
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• pp.55-64
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• 1991

본 연구는 수면전개법으로 고분자 박막을 제조하기 위한 연구로서 PVC 및 CA의 고분자용액의 수면전개 거동과 생성된 박막의 구조특성을 검토하였다. 고분자용액의 수면전개성은 고분자용액의 용매선정에 따른 표면장력, 점도의 변화와 고분자의 농도변화에 따라 영향을 받았다. 또한 수면온도가 증가함에 따라 전개성은 저하되었다. 수면전개 박막의 구조는 고분자농도가 증가할수록 치밀하여 졌으며, 막의 응집상태는 공기면측과 수면측이 다르게 나타나 공기면측의 상태가 다소 치밀하였다. 또한 수면의 온도가 증가할수록 막의 구조는 더 치밀함을 보였다. 한편 3 wt.%의 CA용액으로부터 $0.1{\mu}$의 두께를 갖는 박막을 얻었다.

• 멤브레인
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• 제21권3호
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• pp.229-235
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• 2011

본 연구에서는 메조기공 티타니아/알루미나 막을 솔-젤법을 이용하여 제조하였다. 티타니아/알루미나 막의 기공구조 및 결정상은 하소 온도에 따라 조절될 수 있었다. 티타니아에 알루미나를 첨가하는 것은 티타니아 결정상이 아나타제상에서 루타일상으로 상변화 되는 것을 지연시켜 기공구조의 열적 안정화를 가져왔다. 5번 딥코팅하여 제조된 막의 두께는 $10.3{\mu}m$였으며, 평균 기공크기는 5 nm이었다. 기체 투과 실험 결과는 수소와 질소의 permeance는 각각 $17.1{\tiems}10^{-7}mol/m^2{\cdot}s{\cdot}Pa$ 및 $4.7{\tiems}10^{-7}mol/m^2{\cdot}s{\cdot}Pa$이었다. 이 결과는 Knudsen 확산에 의해 설명될 수 있었다.

• 반도체디스플레이기술학회지
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• 제14권3호
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• pp.7-11
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• 2015

In order to protect the patterned mask from contamination during lithography process, pellicle has become a critical component for Extreme Ultraviolet (EUV) lithography technology. According to EUV pellicle requirements, the pellicle should have high EUV transmittance and robust mechanical property. In this study, silicon nitride, which is well-known for its remarkable mechanical property, was used as a pellicle membrane material to achieve high EUV transmittance. Since long silicon wet etching process time aggravates notching effect causing stress concentration on the edge or corner of etched structure, the remaining membrane is prone to fracture at the end of etch process. To overcome this notching effect and attain high transmittance, we began preparing a rather thick (200 nm) $SiN_x$ membrane which can be stably manufactured and was thinned into 43 nm thickness with HF wet etching process. The measured EUV transmittance shows similar values to the simulated result. Therefore, the result shows possibilities of HF thinning processes for $SiN_x$ EUV pellicle fabrication.