• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.247-247
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• 2009

In this work, Ga-doped ZnO (GZO) thin films for toxic gas sensor application were deposited on low temperature co-fired ceramic (LTCC) substrates, by RF magnetron sputtering method. LTCC is one of promising materials for integration with heater, low cost production and high manufacturing yields than silicon substrate. The LTCC substrates with thickness of $400\;{\mu}m$ were fabricated by laminating 12 greentapes which consist of alumina and glass particle in an organic binder. The GZO thin films deposited on the substrates and were analyzed by X-ray diffraction method (XRD) and field emission scanning electron microscope (FESEM). The films are well crystallized in the hexagonal (wurzite) structure with increasing thickness. The fabricated sensors showed good sensitivity and fast response time to common types of toxic gases (NOx, COx).

• Advances in concrete construction
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• 제5권3호
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• pp.183-199
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• 2017

This paper reports an experimental study into the rheological behaviour of Smart Dynamic Concrete (SDC). The investigation is aimed at quantifying the effect of the varying amount of mineral admixtures on the rheology, setting time and compressive strength of SDC containing natural sand and crushed sand. Ordinary Portland cement (OPC) in conjunction with the mineral admixtures was used in different replacement ratio keeping the mix paste volume (35%) and water binder ratio (0.4) constant at controlled laboratory atmospheric temperature ($33^{\circ}C$ to $35^{\circ}C$). The results show that the properties and amount of fine aggregate have a strong influence on the admixture demand for similar initial workability, i.e., flow. The large amounts of fines and lower value of fineness modulus (FM) of natural sand primarily increases the yield stress of the SDC. The mineral admixtures at various replacement ratios strongly contribute to the yield stress and plastic viscosity of SDC due to inter particle friction and cohesion.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.333-338
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• 2000

The purpose of this study is to evaluate the compressive strength properties of municipal waste ash hardening using the unrefined fly-ash and paper sludge ash and to offer basic data to someone for recycling municipal waste ash. Unrefined fly-ash and paper sludge ash are used with admixture. MWA are tested that grading, specific gravity and pH value and observed microsructure of particle with SEM. The compressive strengths of MWA hardening which is mixed with regular ratio according to each admixture are measured. In the results of test, fly-ash is very effective for reducing content of cement by 50% in the recycling of MWA. But proper content mixed paper sludge ash is recommend by about 20% in binder.

• 한국세라믹학회지
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• 제37권7호
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• pp.721-725
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• 2000

In this study, the dispersion stability of nano-sized CeO2 particles, synthesized by hydrothermal method in aqueous was evaluated from observing the surface potential behavior of CeO2 particle synthesized by solid state reaction. The isoelectric point(IEP) of nano-sized CeO2 synthesized by hydrothermal synthesis was found to be pH 9 contrary to the isoelectric point of micro-sized CeO2 synthesized by solid state reaction at pH 6.7. IEP was shifted to pH 2.0 as the addition of D-3019 from 0.1 to 1.0 wt%. The surface potential of CeO2 particles synthesized by hydrothermal synthesis was reduced as the addition of B-1001 used as a binder without change of IEP because the absorption of B-1001 polymer on the CeO2 particles shifted the shear plane of CeO2 particles outward away from the surface. This surface potential behavior was well correlated with the dispersion stability of slurry.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.267-267
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• 2009

Solar cells with CIGS absorber layers have proven their suitability for high efficiency and stable low cost solar cells. We prepared and characterized particle based CIGS thin film using a non-vacuum processing. CIGS powder were obtained at $240^{\circ}C$ for 6 hours from the reaction of $CuCl_2$, $InCl_3$, $GaCl_3$, Se powder in solvent. The nanoparticle precursors were mixed with binder material. The CIGS thin film deposited on a sodalime glass. The CIGS thin film were identified to have a typical chalcopyrite tetragonal structure by using UV/Visible-spectroscopy, X-ray diffraction(XRD), Auger Electron Spectroscopy(AES), Scanning Electron Microscopy(SEM).

• 대한화학회지
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• 제13권1호
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• pp.49-55
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• 1969

螢光X線을 利用하여 珪酸鹽鑛物中의 主成分인 $SiO_2$, $Al_2O_3$, $Fe_2O_3$, CaO, MgO 및 $K_2O$를 迅速히 分析할 目的으로 試料의 處理 測定 및 各條件에 對하여 檢討하였다. 試料를 Lithium Tetraborate로 용융하여 300Mesh 以上의 微粉末로 한後 40,000Lb의 壓力으로 成型하여 Tungsten과 Chromium 對陰極의 X-線管과 LiF, EDDT, ADP의 分光結晶을 使用하여 測定하였다. 各成分에 對한 檢量曲線은 Matrix Effect를 고려하여 N.B.S 및 International Rock Standard를 選定 使用하였고 Lanthanum Oxide 및 Binder로서 Borie Acid를 첨가하여 얻었다. 各成分에 對하여 本法의 再現性 및 誤差를 檢討하기를 爲하여 I.R.S T-1을 使用하여 測定한 結果 0.47($SiO_2$), 0.85($Al_2O_3$), 0.05($Fe_2O_3$), 0.07(caO), 0.02($K_2O$), 0.13(MgO)의 標準偏差를 얻었다. 또한 化學分析植에 對한 偏差를 求하고져 Clay, Kaoline, Alunite, Wallastonite 및 Zeolite 等의 珪酸鹽鑛物을 選定하여 化學分析 및 本法에 依한 分析結果를 비교하였다.

• 산업기술연구
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• 제12권
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• pp.51-59
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• 1992

In this paper, the technique to fabricate the optical fiber preforms by centrifuge was investigated, using silica particles of different sizes. The injection tube was designed to traverse axially so that uniform coaling of tiny silica particles onto the substrate tube can be certified. The deposition efficiencies and deposition rates of $SiO_2$ particles were measured to elucidate the effects of process variables such as rotation speed of rotor, aqueous flow rate, suspension concentration, binder concentration and overflow weir diameter. This study shows dearly the merit of this technique by enhancing abruptly the deposition rates and deposition efficiencies, comparing to the conventional processes for optical fiber preforms.

• 에너지공학
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• 제2권2호
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• pp.187-193
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• 1993

인산형 연료전시에서의 인산 전해질을 지지하기 위한 다공성 메트릭스의 제조는 결합제인 PTFE와 각종입자의 크기를 갖는 SiC분말 또는 whisker를 혼합 사용하여 제작하였다. 메트릭스로서 갖추어야 될 기본조건중에 bubble pressure와 인산 전해질의 함침량은 전지운영시 전극성능에 가장 큰 영향을 미칠것이라 보아 다공성 전극의 pore size보다 작은 pore size를 가지는 메트릭스를 제작하였다. 각종 SiC입자 크기와 PTFE함량에 따라 제작된 matrix의 bubble pressure와 함침량을 측정하였으며 porosimeter를 이용하여 측정된 메트릭스의 다공도와 비교하여 인산형 연료전지에 사용할 수 있는 최적의 메트릭스 조건을 결정하였다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.223-224
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• 2006

In this paper, rheological characteristics of Metal Injection Moulding (MIM) feedstock using locally binder of palm stearin are presented. The feedstock consisted of 316L-grade stainless steel powder with three different particle sizes and the binders comprise palm stearin and polyethylene. The viscosity of MIM feedstock at different temperatures and shear rates was measured and evaluated. Results showed that, the feedstock containing palm stearin exhibited suitable rheological properties and suitable to produce a homogeneous feedstock that is favorable for injection molding process.

• Korean Chemical Engineering Research
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• 제51권5호
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• pp.628-633
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• 2013

토너 입자 내부의 카본블랙의 분산성이 우수한 스타이렌 기반 현탁중합토너를 제조하기 위하여 카본블랙의 표면을 개질하였다. 산화반응을 통해 카본블랙 표면에 도입된 히드록시기와 유기산(올레산, 팔미트산, 아크릴산)의 카르복시기 사이의 에스터화 반응을 통해 표면이 유기화 개질된 카본블랙을 제조하였다. 카본블랙의 표면개질을 확인하기 위하여 FTIR을 이용하였다. 바인더 수지 모노머 혼합물에 대한 카본블랙의 가시적인 분산성 실험을 진행하였으며 입도분석기를 이용해 분산된 카본블랙의 입자 크기를 측정하였다. 광학현미경 사진을 분석한 결과 표면이 올레산으로 개질된 카본블랙을 사용할 경우 토너 입자 내부의 카본블랙의 분산성이 크게 향상되었다. 올레산으로 개질된 카본블랙을 이용해 제조한 중합토너는 입경 및 입경분포도 토너로서 이상적이었다.