• 한국태양에너지학회 논문집
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• 제28권1호
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• pp.33-42
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• 2008

Zr-O ($Zr-ZrO_2$) cermets solar selective coatings with a double cermets layer film structure were prepared using a DC (direct current) magnetron sputtering method. The typical film structure from surface to bottom substrate were an $Al_2O_3$ anti-reflection layer on a double Zr-O cermets layer on an Al metal infrared reflection layer. Optical properties of optimized Zr-O cermets solar selective coating had an absorptance of ${\alpha}\;=\;0.95$ and thermal omittance of ${\epsilon}\;=\;0.10\;(100^{\circ}C)$. The absorbing layer of Zr-O cermets coatings on glass and silicon substrate was identified as being amorphous by using XRD. AFM showed that ZF-O cermets layers were very smooth and their surface roughness were approximately $0.1{\sim}0.2 nm$. The chemical analysis of the cermets coatings were determined by using XPS. Chemical shift of photoelectron binding energy was occurred due to the change of Zr-O cermets coating structure deposited with increase in oxygen flow rate. The result of thermal stability test showed that the Zr-O cermets solar selective coating was stable for use at temperature below $350^{\circ}C$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1370-1375
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• 2004

This article investigates the heat transfer characteristics in a RTA system for LCD manufacturing and suggests a way to evaluate the quality of a poly-Si film from the thin film optics analysis. The transient and one-dimensional conductive/radiative heat transfer equation considering wave interference effect is solved to predict surface temperatures of thin films. In dealing with radiative heat transfer, a one-dimensional two-flux method is used and the ray tracing method is also utilized to account for the wave interference effects. It is assumed that each interface is assumed diffusive but the spectral radiative properties are included. It is found that the selective heating region exists for various wavelengths and consequently may contribute to heat the poly-Si film. Using the formalism of the characteristic transmission matrix, the lumped structure reflectance, transmittance, and absorptance are calculated and they are compared with experimental data of the poly-Si film during the SPC process via the FE-RTA (Field-Enhanced RTA) technology.

• KIEAE Journal
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• 제12권3호
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• pp.107-114
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• 2012

This is a study that surveyed and analyzed the present status of producing loess construction materials in Korea from 2006 to 2011. The findings are as follows. 1) More than 70% of loess construction material manufacturers are distributed in the capital area. Chungcheong-do and Gyeonggi-do are grown by about 20% on the annual average. 2) Shape of loess brick is possessed mostly by a rectangular parallelepiped. A hole shape, which has 1~5 holes among these things, is possessing a majority. 3) It was indicated to be 42 days as material age for the compressive strength, to be about 2.7Mpa for both extrusion and compression, and to be about 30% for absorptance. 4) Among the whole loess material manufacturers, it accounts for 87 for loess brick 66% for loess mortar and more than 39% for loess paint, but within 10%~15% for other loess products. 5) The main specifications of loess brick are $300{\times}150{\times}150,\;300{\times}150{\times}100,\;300{\times}200{\times}150,\;300{\times}150{\times}200$ in order of the output of 74kinds of loess bricks. 6) In order to improve the strength of building materials, mortar and concrete used loess, it is necessary to examine closely about the effect of ceramic binder and cement on loess products.

• 한국조명전기설비학회지:조명전기설비
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• 제11권6호
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• pp.37-43
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• 1997

광방사에너지에 의해 염료나 안료의 밀도가 감소하며, 밀도 변화는 색변화를 초래한다. 이 연구에서는 방사에너지에 의한 염료밀도의 변화와, 밀도변화에 따른 색변화에 대한 가정을 이용하여 방사에너지에 의한 색변화를 예측할 수 있는 관계식을 만들었다. 또한 실험을 통하여 식중의 손상계수를 산출하였다. 이 식과 계수와 적절성을 검증하기 위하여 시료들을 일반 광원을 변색시키면서 그 변색의 크기를 측정하고 계산치와 비교한 결과, 대부분의 시료에서 일치하는 것을 확인할 수 있었다. 또한 가시 방사대에서 분광 손상계수는 분광 흡수율과 밀접한 관계가 있음을 알 수 있었다.

• Transactions on Electrical and Electronic Materials
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• 제13권1호
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• pp.16-18
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• 2012

LED lighting systems that combine lighting capability, emotional and physiological characteristics are required for lighting source and multifunctional applications. In this work, Simulation studies using optical analysis software packages, Light Tools, are presented. This is done to estimate the uniformity ratio of illuminance and photosynthetic photon flux density (PPFD) of the periodic 2D lattice arrangements, such as square, diamond, two-way bias quadrangular, hexagonal, and Kagome lattices, under the same transmissivity, absorptance and reflectivity. It has been found out that the two-dimensional Kagome lattice arrangement exhibited high uniformity ratio of illuminance and PPFD compared to other lattices. Accordingly, these results can be used to guide a design and improve the lighting environment which in turn would maximize the uniform distributions of illuminance.

• 한국태양에너지학회 논문집
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• 제31권4호
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• pp.48-56
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• 2011

Black cobalt solar selective coatings were prepared by thermal oxidation of electroplated cobalt metal on copper and nickel substrates. The optical properties and structure of the black cobalt selective coating for solar energy utilizations were characterized by glow discharge spectrometry (GDS), ultraviolet-visible-near infrared (UV-VIS-NIR) spectrometer, atom force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS). The optical properties of optimum black cobalt selective coating prepared on copper substrate were a solar absorptance of 0.82 and a thermal emittance of 0.01. From the GDS depth profile analysis of these coatings, the concentration of cobalt particles near the interface was higher than at the surface, but oxygen concentration at the surface was higher than at the interface. These results suggest that the selective absorption was dominated by this chemical composition variation in the coating. The surface of this film exhibited morphology with root-mean-square(rms) roughness of about 144.3nm. XPS measurements data showed that several phases of Co coexist($Co_3O_4$,CoO) in the film.

• 한국태양에너지학회 논문집
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• 제33권4호
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• pp.31-38
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• 2013

The chemical composition of the black Cr solar selective coatings electrodeposited were investigated for property analysis by using a XPS(X-ray photoelectron spectroscopy) before and after annealing in air at $300^{\circ}C{\sim}500^{\circ}C$ for 120 hours. Black Cr selective coating exposed by solar radiation for 5 months was compared with annealed sample. In addition, The Cu solar selective coatings were prepared by thermal oxidation method for low temperature application. The samples obtained were characterized by using the optical reflectance measurements by using a spectrometer. Optical properties of oxidized Cu solar coatings were solar absorptance $({\alpha}){\simeq}0.62$ and thermal emittance $({\epsilon}){\simeq}0.41(100^{\circ}C)$. In the as-prepared Cr black selective coating, the surface of the coating was found to have Cr hydroxide and Cr. The Cr hydroxide of the major component was converted to $Cr_2O_3$ or $CrO_3$ form after annealing at $500^{\circ}C$ with the desorption of water molecules. The black Cr selective coating was degraded significantly at temperature of $500^{\circ}C$. The main optical degradation modes of this coating were diffusion of Cu substrate materials.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.61-64
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• 2008

콘크리트충전 강관기둥(Concrete Filled steel Tube Column)과 RC 무량판 슬래브의 조합은 거푸집을 사용하지 않는다는 것만으로도 초고층 건물의 공기단축에 상당한 영향을 미칠 수 있다. 뿐만 아니라 기둥의 내력 증진으로 인한 기둥 크기의 축소, 그로 인한 공간 활용도의 증가, 층간 소음문제 해결 등 많은 장점이 잠재되어 있다. 하지만 접합부의 성능을 정확히 밝혀내는 것이 우선 이루어져야 하며, 본 논문에서는 기존에 수행된 CFT 기둥-RC 무량판 슬래브의 내부접합부에 대한 중력 실험과 횡하중 실험을 바탕으로 외부접합부에 대한 실물대 실험을 수행하였다. 외부접합부 실험 결과, 내부접합부 실험체에 비하여 동일한 조건에서 설계된 외부접합부 실험체는 최대 모멘트강도가 $50%{\sim}65%$ 감소하였고, 내진밴드가 추가된 CFT-E2 실험체는 BME 실험체에 비하여 20%의 최대모멘트 증진과 탁월한 연성능력, 에너지 흡수능력을 보유한 것으로 나타났다. 또한 CFT-E2는 내진밴드의 사용으로 슬래브의 휨거동 영역이 확장되었으며 모든 실험체가 설계기준에서 요구하는 0.4V$_c$중력하중 하에서 1.5% 횡변 위비를 만족하였다.

• 생물환경조절학회지
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• 제23권4호
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• pp.314-320
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• 2014

소형 비닐하우스에 2종류의 기능성 필름과 관행의 PE 필름을 피복하고 청치마, 적치마, 치커리 등 3종의 엽채류를 재배하여 기능성필름의 특성을 검토하였다. 2종류의 기능성 필름은 PO(polyorefine)계 수지로 만들어졌으며, 엽채류는 흙과 펄라이트를 혼합한 배지에서 육묘하였다. 필름의 광학적 특성에 있어서 기능성 필름은 관행의 PE 필름과 비교하여 광합성 유효광(400-700nm)의 투과율이 높고 자외선(300-400nm)의 흡수율이 높았다. 피복 3개월 후의 광합성 유효광 투과율의 감소 수준은 기능성필름이 PE필름보다 작았다. 이 같은 요인으로 인해 엽채류의 생육과 수량이 기능성 필름을 피복한 하우스에서 높았다.

• 환경위생공학
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• 제12권1호
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• pp.25-37
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• 1997

The synthesis of high purity and ultra-fine $BaTiO_{3}$ by precipitation with gaseous $NH_{3}$ as precipitator was investigated to find an alternative process to solve various problems of present wet methods. This study consisted of two parts ; synthesis of $BaTiO_{3}$ precipitation with gaseous $NH_{3}$ and test of electrical property for the $La_{2}O_{3}$ doped $BaTiO_{3}$. The proper condition for the synthesis of $BaTiO_{3}$ by precipitation with gaseous $NH_{3}$ is as follows. The pH was 9.0. $H_{2}O_{2}$ mole ratio to $TiCl_{4}$ was 10. $NH_{3}$ gas follow rate did not influence the synthesis of $BaTiO_{3}$. The calcination temperature of $BaTiO_{3}$ was $300^{\circ}C$. Also, the synthesis of $La_{2}O_{3}$-doped $BaTiO_{3}$ was tested through the wet process. Under these condition, the shape of prepared $BaTiO_{3}$ powder was spherical type and the size of that was about $0.2{\mu}m$. After the powder was pressed, this green body was sintered at the $1300^{\circ}C$. Under these conditions, the water absorptance and the density of the obtained sintered body were below 0.04 %, 5.2 g/$cm^{3}$, respectively. Also the grain size of that was about $10{\mu}m$ and it was similar to commercial product.