• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.300-303
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• 2010

다양한 형상의 인젝터 내부 젤 추진제 유동을 수치적으로 연구하였다. 모사 젤 추진제의 유변학적물성치를 측정하고 plain-orifice, chamfered-orifice 및 venturi 형상 인젝터의 유동 특성을 분석하였다. Plain-orifice 및 chamfered-orifice 인젝터의 경우 하류방향으로 유동이 진행할수록 점도가 높아지는 특성이 나타났으며 Venturi 형상의 경우 인젝터 내부 유동에서 낮은 점도가 지속적으로 유지됨을 알 수 있었다. Reynolds 수가 증가할수록 이러한 경향이 뚜렷하게 나타나는 것이 확인되었다.

• 한국응용과학기술학회지
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• 제25권2호
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• pp.130-136
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• 2008

$xTiO_2$-$ySiO_2$ system photocatalysts were developed by sol-gel method based on the change of production parameters, and their structure of crystallization and the specific surface area were measured. Considering the efficiency of the ethanol and phenol degradation using the catalyst, the conclusions were obtained as follows: By means of X-ray analysis of $xTiO_2$-$ySiO_2$ powder that is obtained from Titanium and Silicon alkoxide by sol-gel process, it is shown that crystal structure of anatase type is a dominating structure and, on the other hand, the structure of rutile also partly exists. The increase of $SiO_2$ contents causes the decrease of the degree of crystallization of the gel, whereas the specific surface area preferentially increases. It is shown that more than 90% of ethanol and phenol are degraded when reaction time is about three and an hours, and the maximum degradation rate of ethanol and phenol is shown in $60TiO_2$-$40SiO_2$ catalyst.

• 동력기계공학회지
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• 제15권4호
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• pp.75-78
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• 2011

There are various types of materials used in electronic industry, such as electrode material, conductor, insulator, anode, cathode and semiconductor. Electrode material type is Cu, Ti, ZnO and so on. Especially if we use mixed ZnO in soil cement or silica gel, we can have advantages in ice road to prevent freezing. We have great impact if we use supported in inorganic substances like silica gel. In this paper we have studied that ZnO supported silica gel and its properties. Zinc acetate dissolved in distilled water were loaded on the silica gel by the reaction with ammonia at $80^{\circ}C$. And we investigated particle structures of ZnO by scanning electron microscopy(SEM) and X-ray diffraction(XRD).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1247-1250
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• 2008

This presentation highlights work from the authors' laboratories on the various kinds of oxide optical materials, mainly luminescence and pigment materials with different forms (powder, core-shell structures, thin film and patterning) prepared by the Pechini-type sol-gel (PSG) process. The PSG process which uses the common metal salts (nitrates, acetates, chlorides etc) as precursors and citric acid (CA) as chelating ligands of metal ions and polyhydroxy alcohol (such as ethylene glycol or poly ethylene glycol) as cross-linking agent to form a polymeric resin on molecular level, allowing the preparation of many forms of luminescent materials.

• 한국작물학회지
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• 제44권1호
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• pp.64-69
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• 1999

Gelatinization characteristics of 111 glutinous rice varieties were evaluated by Rapid Visco Analyzer. Gelatinization viscosity of glutinous rice tested varied with ecotypes or varietal groups: indica, japonica, and Tongil type. Indica rice showed the highest average value of initial pasting temperature. The average values for peak, hot, and cool viscosities were highest in Tongil-type rice, and lowest in japonica rice. Japonica showed the lowest breakdown and consistency, but the highest setback value. Indica was lower in alkali digestion value (ADV), and shorter in gel length after gelatinization thanjaponica and Tongil-type. Glutinous rices tested could be divided into six groups by cluster analysis based on their gelatinization characteristics. Group I-A was mostly early maturing japonica varieties while I-B was mostly indica and Tongil-type rices. Groups II-A and II-B were consisted of very early maturingjaponica, and III-A and III-B included medium or medium late maturingjaponica varieties. Group III-A showed the lowest average values of peak, hot, cool, and consistency viscosities, and also in breakdown and setback ratios. Group I-B revealed the highest values in peak, hot, cool, breakdown, and consistency viscosities. ADV was low in groups I-A, I-B, and II-B, and gel consistency was not different among the six varietal groups. Principal component analysis using seven traits related with gelatinization produced four effective components, and the first and second components were highly correlated with all the gelatinization characters evaluated.

• Journal of Pharmaceutical Investigation
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• 제32권3호
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• pp.165-172
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• 2002

Injectable gel composed of egg phosphatidylcholine (egg PC), hyaluronate (HA) and water was formulated for local drug delivery. The lamellar liquid crystalline structure of the egg PC/water system did not change by adding HA in the formulation. However, egg PC/HA/water gel was more resistant to erosion than the egg PC/water gel. The egg PC/HA/water and egg PC/water gels containing model drugs, tetracycline and sudan IV were prepared to perform in vitro and in vivo drug release experiments. In vitro release of tetracycline was sustained in the gel type formulations. The release rate of hydrophobic sudan IV was extremely slow. More than 99% of sudan IV remained inside the gel after 5 days. In vivo release of drugs from the air pouch model in Balb/c mice shows that lipophilic sudan IV remained for more than 10 days whereas tetracycline remained for 1 day in the pouch. The compatibility of the gels was also examined by histopathology. The gels did not cause any adverse inflammatory effect in the air pouch.

• 공업화학
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• 제28권2호
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• pp.153-157
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• 2017

Hydroxyethyl-cellulose (HEC) 함량별로 겔 타입 내부전해질을 제작하여 이온전도도와 내구성 측정 실험을 수행하였다. 이온전도도 측정결과 HEC 함량이 증가할수록 이온전도도가 감소하여 12% 함량의 겔 타입 내부전해질은 기준전극에 적용이 어려울 것으로 판단하였다. HEC 함량별 내구성 실험결과, HEC의 함량이 감소할수록 carrier density가 증가하여 다공성 막을 통해 유출되는 전해질(KCl)의 양이 증가하였다. 따라서 선박평형수 처리장치와 같이 장시간 사용하기 위해 겔 타입 내부전해질을 HEC 10%로 선정하였다. HEC 10%의 겔 타입 내부전해질을 이용하여 기준전극과 TRO (total residual oxidants) 센서를 제작하여 TRO 분리능 실험을 수행하였다. TRO 센서에 50 mV의 전위를 30 s 동안 동일하게 인가하여 전류변화를 비교한 결과 0.2~30 PSU 조건에서 0~15 mg/L의 TRO 농도가 분리됨을 확인하였다. 따라서 HEC를 이용한 겔 타입 내부전해질을 TRO 센서에 적용할 수 있으며, 이를 이용하여 담수뿐만 아니라 해수 조건에서 TRO를 측정할 수 있음을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.255-256
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• 2018

In this study, to confirm the performance of gel type urethane (hereinafter referred to as urethane gel) developed for the purpose of securing waterproof stability after application by increasing compatibility with asphalt mastic film material, general urethane coating material and adhesion. As a result, gel type urethane showed "all right" in fatigue resistance test.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.350-350
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• 2013

Sol-gel법을 이용하여 p-Si 기판위에 yttrium이 도핑된 ZnO (YZO)를 성장하였다. ZnO의 precursor로는 zinc acetate dihydrate를, yttrium의 source로는 yttrium acetate hydrate를 사용하였으며, 용매와 안정제로는 각각 2-methoxy ethanol과 monoethanolamine (MEA)를 사용하였다. yttrium의 doping 농도에 따른 영향을 알아보기 위하여 1~4 at.%로 제작된 YZO sol을 각각 p-type Si 기판에 성장하였으며, 이 후 furnace를 이용하여 500oC에서 1시간 동안 열처리하였다. 성장된 YZO 박막의 표면과 두께를 SEM을 통하여 확인하였으며, XRD를 통한 구조적인 특성을 분석한 결과 모든 박막에서 뚜렷한 c-축 배양성을 갖는 ZnO (0002)피크를 확인하였다. Hall effect를 통하여 YZO는 모두 n-type 특성을 나타낸다는 것을 확인하였으며, 광학적인 특성은 PL을 통해서 분석하였다. n-YZO/p-Si 이종접합의 전류-전압 특성을 분석한 결과 뚜렷한 정류특성을 나타내었다.

• 한국전기전자재료학회논문지
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• 제29권12호
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• pp.759-763
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• 2016

We demonstrate the utilization of ion gel gate dielectrics for operating non-volatile transistor memory devices based on polymer semiconductor thin films. The gating process in typical electrolyte-gated polymer transistors occurs upon the penetration and escape of ionic components into the active channel layer, which dopes and dedopes the polymer film, respectively. Therefore, by controlling doping and dedoping processes, electrical current signals through the polymer film can be memorized and erased over a period of time, which constitutes the transistor-type memory devices. It was found that increasing the thickness of polymer films can enhance the memory performance of device including (i) the current signal ratio between its memorized state and erased state and (ii) the retention time of the signal.