• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.615-616
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• 2005

Carbon Nanotubes (CNT) on flexible indium tin oxide (ITO) PET films were prepared for dye-sensitized solar cell (DSSC). These CNTs were prepared by spray coating method for various amount of light transparency. Also, Pt counter electrode was prepared by electro deposition method. All $TiO_2$ electrodes were deposited on ITO-PET films by spray coating method. Micro structural images show that CNT counter electrodes prepared by spray-coating have more dense structure with increasing spraying time (0 to 60 seconds). DSSC consisting of $TiO_2$ electrode and CNT counter electrode was fabricated with various amount of light absorption. DSSC have higher light energy conversion efficiency with increasing the thickness of CNT counter electrode. CNT counter electrode is at least compatible to that of CNT counter electrode.

• Nuclear Engineering and Technology
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• 제51권4호
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• pp.1069-1074
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• 2019

A novel fabrication method of oxide dispersion strengthened (ODS) steel cladding tubes for advanced fast reactors has been investigated using the cold spray powder-based materials deposition process. Cold spraying has the potential advantage for rapidly fabricating ODS cladding tubes in comparison with the conventional multi-step extrusion process. A gas atomized spherical 14YWT (Fe-14%Cr, 3%W, 0.4%Ti, 0.2% Y, 0.01%O) powder was sprayed on a rotating cylindrical 6061-T6 aluminum mandrel using nitrogen as the propellant gas. The powder lacked the oxygen content needed to precipitate the nanoclusters in ODS steel, therefore this work was intended to serve as a proof-of-concept study to demonstrate that free-standing steel cladding tubes with prototypical ODS composition could be manufactured using the cold spray process. The spray process produced an approximately 1-mm thick, dense 14YWT deposit on the aluminum-alloy tube. After surface polishing of the 14YWT deposit to obtain desired cladding thickness and surface roughness, the aluminum-alloy mandrel was dissolved in an alkaline medium to leave behind a free-standing ODS tube. The as-fabricated cladding tube was annealed at $1000^{\circ}C$ for 1 h in an argon atmosphere to improve the overall mechanical properties of the cladding.

• 한국재료학회지
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• 제29권1호
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• pp.52-58
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• 2019

The microstructure, hardness, and wear behaviors of a High Velocity Oxygen Fuel(HVOF) sprayed WC-CoFe coating are comparatively investigated before and after laser heat treatments of the coating surface. During the spraying, the binder metal is melted and a small portion of WC is decomposed to $W_2C$. A porous coating is formed by evolution of carbon oxide gases formed by the reaction of the free carbon and the sprayed oxygen gas. The laser heat treatment eliminates the porosity and provides a more densified microstructure. After laser heat treatment, the porosity in the coating layer decreases from 1.7 % to 1.2 and the coating thickness decreases from $150{\mu}m$ to $100{\mu}m$. The surface hardness increases from 1440 Hv to 1117 Hv. In the wear test, the friction coefficient of coating decreases from 0.45 to 0.32 and the wear resistance is improved by the laser heat treatment. The improvement is likely due to the formation of oxide tribofilms.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.35-36
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• 2023

Safety management of steel frame members is a very important part to maintain safety and function. However, precise inspection is not possible for steel frame members due to finishing materials and insulation materials, leading to poor inspection. For steel members, an insulating spray coating method is used for high thermal conductivity. The insulation spray method is not only uneconomical, but also has the disadvantage of spoiling the aesthetics. In addition, VOCs are released from paints used in spraying, so a solution is needed. In this study, heating paint was used to improve the disadvantages of the insulation spray coating method and the high thermal conductivity of steel frame members. In addition to this, in order to reduce VOCs generated from the paint, active clay was added to produce a functional exothermic paint, and then the experiment was conducted. As the amount of activated clay increased, the film thickness increased, and the VOCs emission and thermal conductivity decreased.

• 한국건설순환자원학회논문집
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• 제6권1호
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• pp.103-110
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• 2011

본 연구는 폐콘크리트로부터 발생한 성토 복토용 순환잔골재의 pH 저감을 목적으로 자연적 처리 방법 및 인위적 처리 방법을 이용하여 순환잔골재의 pH 저감특성을 비교 분석 하고자 하였는데, 그 결과를 요약하면 다음과 같다. 실내방치된 순환잔골재의 경우는 사람의 호흡 등 대기중 높은 $CO_2$농도로 인해 실외방치된 순환잔골재보다, 또한 쌓기 두께가 얇을수록 pH를 저감시킨 것으로 분석된다. 공기투과의 경우 비교적 순환잔골재의 pH저감이 효과적이었는데 이는 고압의 환풍기로 인해 순환잔골재에 원활한 $CO_2$ 공급으로 pH를 저감시킨 것으로 판단된다. 살수처리의 경우 미수화 시멘트의 수화반응을 촉진시켜 수산화칼슘을 용해시키고, 건조과정중 대기중 $CO_2$에 의한 중성화로 pH를 크게 저감시키는 것으로 나타났으며 침수처리에서는 pH 저감 효과가 미흡하였다. $CO_2$촉진의 경우 순환잔골재의 pH저감 효과가 가장 우수한 것으로 나타났는데, 이는 원활한 $CO_2$공급이 가능하기 때문인 것으로 분석된다. 이상의 실험 결과를 종합하면, pH 저감성능, 경제성 및 작업성 측면을 고려할 경우 순환잔골재 질량비 1: 0.5 비율로 살수한 다음, 강제적인 $CO_2$가스의 처리로 건습을 반복한다면 순환잔골재의 pH저감에 가장 효과적인 방법이 될 것으로 분석된다.

• Journal of Plant Biology
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• 제30권1호
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• pp.21-30
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• 1987

The effects of abscisic acid(ABA) spraying for 12 weeks on the stomatal types and frequencies of O. malacophyllus leaves were summarized as follows. ABA inhibited the growth of O. malacophyllus. The prominent effect of ABA on the epidermal structure was the promotion of senescence such as thickness of cell walls, smooth sinuosity of cell walls, and large size of epidermal cells. The stomatal frequency was decreased to 23% by 10$\mu\textrm{g}$ ml-1 ABA and to 48% by 100$\mu\textrm{g}$ml-1, and also the stomatal size was more or less smaller than that of control. The developing secondary stomatal mother cell was not found in both 10 and 100$\mu\textrm{g}$ml-1ABA, but the arrested secondary stomatal mother cell was rarely found in 10$\mu\textrm{g}$ ml-1 ABA. The formation of normal stomatal types such as helico-eumesogenous and aniso-eumesogenous was found in both 10 and 100 $\mu\textrm{g}$ ml-1 ABA asin well as control. Also nine abnormal stomatal types were found, and the frequencies were promoted to 6% by 10 $\mu\textrm{g}$ ml-1 ABA and to 17% by 100 $\mu\textrm{g}$ ml-1 ABA. Among these abnomal stomata, four types such as aborted stomata, single-aborted guard cells, arrested stomata, and modified stomatal complexes were found in control as well as in 10 and 100 $\mu\textrm{g}$ ml-1 ABA, but five types such as wrenched stomata, unequal stomata, wavy guard cells, guard cells overlapped by guard cells, and dissolved cell wall stomata were found in both 10 and 100 $\mu\textrm{g}$ ml-1ABA. The modified stomata complexes were abnormal stomatal types which were newly found and also were varied in types.

• 태양에너지
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• 제17권2호
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• pp.55-66
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• 1997

CdTe/CdS 태양전지 제작에 필요한 다결정 CdS 박막을 ITO 전도 유리기판위에 SSD법, SPD법 및 CBD법 으로 제작하고 열처리 한 후 그 결정구조와 광학적 특성을 조사하였다. 박막은 모두 Wurtzite 구조를 보였고 SSD법과 CBD법의 박막은 $0.5{\mu}m$ 크기의 CdS 입자가 불규칙적으로 형성되어 증착되어 있음을 보였고, $400^{\circ}C$로 진공중에서 열처리 할 때 입자의 크기가 약간 증가하였다. SPD법의 박막은 (002)방향으로 결정이 성장되고 입자의 크기가 $0.1-0.3{\mu}m$ 이었다. 에너지 밴드갭 및 결함 상태를 광학적 흡수, 광 루미니센스, 라만 및 광 열 편기 스펙트럼(PDS) 측정을 통해 조사하였다.

• Progress in Superconductivity
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• 제9권1호
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• pp.102-106
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• 2007

YBCO films have been synthesized using a spray pyrolysis method. We used nitrates of Y, Ba, Cu as precursors. Deposition was made on $LaAlO_3$ (100) single crystal substrate by spraying the mist of aqueous precursor solution generated by a concentric nozzle. The distance between concentric nozzle and substrate was 15 cm. C-axis oriented films were obtained at deposition temperature of $740{\sim}800^{\circ}C$ and working pressure of 20 Torr. Oxygen partial pressure was 3 Torr and substrate was transported with the speed ranging from 0.23 cm/min to 0.7 cm/min by reel to reel. Scanning electron microscope (SEM) and X-ray diffraction (XRD) observation revealed that films are smooth and highly textured with (001) planes parallel to substrate. Highest critical current density (Jc) was $1.38\;MA/cm^2$ at 77K and self-field for the film with a thickness of $0.5\;{\mu}m$ prepared at a substrate temperature of $780^{\circ}C$ and $PO_2\;=3\;Torr$. The effect of temperature on the microstructure and YBCO phase formation will be discussed.

• 한국통신학회논문지
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• 제18권8호
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• pp.1169-1175
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• 1993

레이다의 추적 및 탐색으로 부터 비행 물체를 보호하기 위한 목적으로, 알루미늄 합금표면에 페라이트-탄화규소 복합물인 마이크로파 흡수층을 플라즈마 용사방식으로 제작하였다. 본 논문에서는 페라이트-탄화규소층(I) 제조시 사용했던 탄화규소 입자의 평균크기인 34[rm]대신에15[rm]가 사용되었으며, 플라즈마 용사변수들 중에서 분말의 공급비율은 70[Kg/h]대신에 50[Kg/h] 그리고, 용사거리는 80[mm[ 대신에 100[mm]가 사용 되었다. X-band(8~12.4(GHz)레이다용 페라이트-탄화규소 전자파 흡수체를 실험적으로 설계하고 시험제작하여 전기적 특성을 평가한 결과, -lOdB의 반사량을 허용한도로 했을 때 약 2.8%의 대역폭이 얻어졌으며, 최대 흡수두께는 0.5(mm)로 매우 양호한 박층형 전자파 흡수체가 얻어졌다.

• 한국세라믹학회지
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• 제41권3호
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• pp.259-265
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• 2004

플라즈마 용사법에 의해 나노크기의 하이드록시 아파타이트 분말을 지르코니아 소결체 기판에 용사한 후 코팅층의 미세조직에 대해 조사하였다. 나노크기의 하이드록시 아파타이트 분말은 Ca(NO$_3$)$_2$$.$4$H_2O$과 (NH$_4$)$_2$HPO$_4$ 용액을 이용한 침전법에 의해 성공적으로 합성되었다. 코팅 후 지르코니아 기판과 코팅층 계면에서 균열은 발생하지 않았으며 코팅층의 두께는 150-250 $\mu\textrm{m}$였다. 나노크기의 하이드록시아파타이트 분말과 용사된 HAp코팅층에서는 비이상적인 상들의 출현이 발견되지 않았다. 80$0^{\circ}C$에서 열처리된 코팅층의 경우 하이드록시 아파타이트 이외에 TTCP와 $\beta$-TCP같은 상이 관찰되었지만 열처리온도 90$0^{\circ}C$에서 TTCP와 $\beta$-TCP상은 소멸되었다. XRD 분석결과, 열처리온도 110$0^{\circ}C$에서 HAp코팅층은 높은 결정화도를 나타내었다.