• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.586-589
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• 2004

Ni 내부전극을 적용한 X7R의 온도특성을 가지는 고압용 적층 칩 캐패시터를 설계, 제작하였으며 제작된 캐패시터 신뢰성을 검토하였다. 고압용 캐패시터 설계시 절연파괴전압과 유전체 두께간의 최적의 두께가 있음을 볼 수 있으며 그린시트 두께 24 um의 경우 weibull 계수는 13.38, 단위 절연파괴전압은 70 [V/um]을 얻을 수 있었다. X7R 3216, 100 [nF] 정격전압 250[V] 캐패시터를 설계하여 절연파괴전압은 최고 1.29 [KV]인 고압용 칩 캐패시터를 제작하였다. 적층 칩 캐패시터 절연파괴 모드는 유전체 층간의 절연파괴와 더불어 내부전극과 외부 전극 또는 세라믹 소체와의 절연파괴 모드가 나타남을 볼 수 있다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.367-369
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• 2009

플렉서블 태양전지용 연성기판재에는 플라스틱재와 금속재가 있다. 기존의 연성기판인 플라스틱의 경우 열과, 내구성, 화학약품에 약하다는 단점이 있으며, 금속기판은 높은 생산원가, 박판화의 어려움 등의 문제를 안고 있다. 일반적으로 기판재와 cell을 구성하는 반도체 층의 열팽창 거동 차이에 의한 열 변형이 태양전지의 공정안정성에 영향을 주는 것으로 알려져 있으며, cell을 구성하는 반도체 층과 열팽창 거동이 유사한 금속기판재의 적용이 필요하다. Si 박막 태양전지의 경우 Si 열팽창 거동과 비슷한 특성을 갖는 기판재의 개발이 필요하다. 전주법을 적용하여 조성이 다른 Ni계 합금의 열팽창 거동을 TMA 장비를 사용하여 측정하였다. 그리고 전산해석 Tool을 활용하여 가상의 Si 박막 태양전지 제조공정을 설정하고 고온 공정온도에서 상온으로 냉각시 발생되는 층간 열변형 연구를 수행하였고 열팽창 거동이 다른 합금 상에 Si층을 증착하여 열 충격에 의한 결함 발생여부를 관찰하였다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.357-360
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• 2011

고층 건축물에 주로 사용되는 커튼월의 경우 구조체와의 접합으로 인해 층간 틈새가 발생하게 되고 이는 화재 시 틈새를 통해 화염이나 연기 등의 확산 경로가 될 수 있다. 본 연구에서는 커튼월 시스템에 적용되는 선형조인트 내화충전시스템의 개발을 위해 경제적이고 시공이 간편한 박스형 시스템을 도입하고 내부에 다양한 변경하여 내화성능을 평가하였으며, 그 결과 케이싱 내부의 단열재 20mm두께의 내화 뿜칠재와 석고보드를 케이싱 안쪽에 박스 형태로 구성한 시스템이 가장 안정적이고 온도상승도 작은 것으로 나타났다.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.101-110
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• 2010

In this paper, it has been studied about the CRCO to maintain or rehabilitate the aged JCP. The CRCO and JCO was constructed at useless section of Seo-Hae-Ahn express highway in South Korea. The performance evaluation was conducted. Especially, it was focused on the roll of longitudinal reinforced steels inserted into the CRCO. On crack survey results from field construction section, the reflection cracks at joint of the existing pavement occurred in CRCO. However, due to the constraints of longitudinal reinforced steels, crack width was small. Total crack length and quantity in the CRCO more than that in the JCO. And crack spacing in the CRCO was narrower than it in the CRCP. Through the bonding strength test results, if the cold milling and cleaning as well as surface treatment is applied, there will be no debonding problem at interlayer in the early age. From analysis of the horizontal behavior at the joint, the longitudinal reinforced steels constrained crack width which became wider than initial state over time. Also, that steel in the CRCO reduced the horizontal movement due to temperature variation(4 times than that in the JCO). But, if interface is debonded, the roll decreased. Vertical VWG data showed that CRCO did not occur debonding problem at steel location, but there was some problem in JCO. It was confirmed by field coring. The tensile strain appeared in the CRCO, But the compressive strain occurred in the JCO in early age. Through the FWD test result, deflection in the CRCO was less than that in the JCO. And K value in the CRCO was greater than it in the JCO.

• Journal of Animal Environmental Science
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• v.14 no.3
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• pp.183-192
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• 2008

This study was carried out to investigate the temperature, water balance, evaporation and physicochemical properties during the composting with pig slurry at a scraper system. The pig slurry was composted on farm trial using continuous aeration with turning machine for 5 month. A compost facility of rectangular concrete bin with dimension of 53 m (length) ${\times}$ 4.6 m (width) ${\times}$ 2 m (height) was bedded with sawdust. The environmental parameters were monitored in period of 5 months. The results were as follows ; 1. During the composting period, the temperature was varied in the range $50{\sim}70^{\circ}C$. The temperature of compost pile was highest in middle layer and lowest in under layer. Temperature difference between middle and under area of compost pile was $5{\sim}20^{\circ}C$. 2. The water content of compost pile varied $50{\sim}68%$. In the period of 50% of water content of compost pile, the temperature of compost was $20{\sim}30^{\circ}C$ and was not successfully composted. 3. In this study, total evaporation was 90% during composting. The amount of slurry per $1m^3$ sawdust by this method was $3.16m^3$ without treatment of effluent output. 4. The chemical properties of produced compost was high, but suitable for plant growth. Concentration of T-N, T-C in the final compost were 1.62, 34%, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.129-129
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• 2010

적외선 검출소자(Infrared Photodetector)는 근적외선에서 원적외선 영역에 이르는 광범위한 파장 범위의 적외선을 이용하는 기기로서 대상물이 방사하는 적외선 영역의 에너지를 흡수하여 이를 영상화할 수 있는 장비이다. 적외선 관련 기술은 2차 세계대전 기간에 태동하였으며, 현재에는 원거리 감지기술 등과 접목되면서 그 활용 분야가 다양해지고 있다. 특히 능동형 정밀 타격무기를 비롯한 감시 정찰 장비 및 지능형 전투 장비 시스템 등에 대한 요구를 바탕으로 보다 정밀하고 신속한 표적 감지 및 정보처리 기술에 관한 연구가 선진국을 통해서 활발히 진행되고 있다. 기존의 Bolometer 형식의 열 감지 소자는 반응 속도가 느리고 측정 감도가 낮은 단점이 있으며, MCT(HgCdTe)를 이용한 적외선 검출기의 경우 높은 기계적 결함과 77K 저온에서 동작해야하기 때문에 발생하는 추가 비용 등이 문제점으로 지적되고 있다[1]. 이에 반해 화합물 반도체 자기조립 양자점(self-assembled quantum dot)을 이용한 적외선 수광소자는 양자점이 가지는 불연속적인 내부 에너지 준위로 인하여, 높은 내부 양자 효율과 온도 안정성을 기대할 수 있으며, 고성능, 고속처리, 저소비전력 및 저소음의 실현이 가능하다. 본 연구에서는 적층 InAs/InGaAs dot-in-a-well 구조를 유기금속화학기상증착법을 이용하여 성장하고 이를 소자에 응용하였다. 균일한 적층 양자점의 성장을 위해서 원자현미경(atomic force microscopy)을 이용하여, 각 층의 양자점의 크기와 밀도를 관찰하였고, photoluminescence (PL)를 이용하여 발광특성을 연구하였다. 각 층간의 GaAs space layer의 두께와 온도 조절 과정을 조절함으로써 균일한 적층 양자점 구조를 얻을 수 있었다. 이를 이용하여 양자점의 전도대 내부의 에너지 준위간 천이(intersubband transition)를 이용하는 n-type GaAs/intrinsic InAs 양자점/n-type GaAs 구조의 양자점 적외선수광소자 구조를 성장하였다. 이 과정에서 상부 n-type GaAs의 성장 온도가 600도 이상이 되는 경우 발광효율이 급격히 감소하고, 암전류가 크게 증가하는 것을 관찰하였다. 이는 InAs 양자점과 주변 GaAs 간의 열에 의한 상호 확산에 의하여 양자점의 전자 구속 효과를 저해하는 것으로 설명된다.

• Solar Energy
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• v.15 no.2
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• pp.91-99
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• 1995

The influence of deposition parameters on the deposition of $SnO_2$ thin films by spray pyrolysis has been studied. In the case of spray solution with tile concentration of 0.01M, at low deposition temperature the deposition was controlled by surface reaction and portion controlled by mass transfer is increased with increasing deposition temperature to $400^{\circ}C$. Above $400^{\circ}C$, the deposition is controlled by mass transfer at low spray pressure, and by surface reaction at high spray pressure. As the concentration of spray solution increased the deposition rate increased, and in this experiment the deposition depends on the Rideal-Eley mechanism. The deposition rate increased with increasing substrate temperature up to $400^{\circ}C$ and then decreased due to homogeneous nucleation. The thickness of the deposit increased with increasing spray duration, and the adhesion between substrate and deposit was formed physically.

• Analytical Science and Technology
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• v.6 no.5
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• pp.479-487
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• 1993

Potassium-Graphite Fiber Intercalation Compounds(K-GFIC) have been prepared from well oriented pitch-based Graphite fiber by the transformed two-bulbs method with variation of reaction temperatures of graphite($T_g$ : $450^{\circ}C$, $400^{\circ}C$, $350^{\circ}C$, $300^{\circ}C$, $250^{\circ}C$). The stage transition process of K-GFICs was studied by X-ray diffraction methods, and we have observed peaks with d-values of (001) diffraction of $5.40{\AA}$ and $8.78({\pm}0.01){\AA}$, which are charecteristic for the stage 1 and stage 2, respectively. The stage stability and energy states of K-GFICs were studied by UV/VIS spectrophotometer. As a results, We found that the minimum values of reflactance of K-GFICs with pure stage was moved to higher energy pristine Graphite fiber's. But because of mixtured stage, we could not observe minimum reflectance in the visible region at high reaction temperatures($400^{\circ}C$, $450^{\circ}C$). From X-ray diffraction and UV/VIS sepctrophotometry data, we can suggest that K-GFICs with lower stage has many charge carriers existed between C atoms of graphite Layers. And then, these results also provides information on the electrical and other physical properties of K-GFICs.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.150-154
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• 1990

Various sterilization temperatures $(110^{\circ}C,\;120^{\circ}C,\;130^{\circ}C)$ and air volumes (air, 31ml, half-vacuum; 13ml, vacuum; -0.7ml) within the retort pouch were tested for the development of the simple retort rice processing techniques in which the pouch were filled with rice and water, and then sterilized. Water content of retort rice was found to be 59.0-63.3% resulting from mixing the rice and water in the ratio of 1:1.1. The most uniform water content was obtained from retort rice sterilized at $130^{\circ}C$ and packaged under vacuum. The larger water content differences were observed with the increase in internal air volumes within the retort pouch. Spreading degree of retort rice was geater than that of general cooked rice, was lower in upper layer than in low layer, and became lower with the larger air volume and higher sterilization temperature. a degree of rice became higher with the Increase of sterilization temperature but that was not affected by the internal air volume of the pouch. The higher sterilization temperature and the lower the air volume, the higher the whiteness was. The highest whiteness was obtained by packaging under vacuum and sterilizing at $130^{\circ}C$. Intact degree was much higer in packaging under air than vacuum. In sensory evaluation the retort rice of vacuum pack was good in color and spreading degree but not in appearance because of blocking and deforming, but that of air pack was good in texture on the contrary. The best quality was obtained by packaging under half-vacuum and sterilizing at $130^{\circ}C$.

• Composites Research
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• v.33 no.3
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• pp.161-168
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• 2020

In this paper, we have studied the mechanical properties of thermoplastic carbon fiber fabric composites with spread technology and compression molding temperature were investigated. Carbon fiber reinforcement composites were fabricated using commercial carbon fiber fabrics and spread carbon fiber fabrics. Mechanical properties of the commercial carbon fiber composites (CCFC) and spread carbon fiber composites (SCFC) according to compression molding temperatures were investigated. Thermal properties of the polypropylene film were examined by rheometer, differential scanning calorimetry, thermal gravimetric analysis. Tensile, flexural and Inter-laminar shear test. Commercial carbon fiber reinforcement composites and spread carbon fiber composites were fabricated at 200~240℃ above the melting temperature of the polypropylene film. Impregnation properties according to compression molding temperature of the polypropylene film were investigated by scanning electron microscopy. As a result, as the compression molding temperature was increased, the viscosity of the polypropylene film was decreased. The mechanical properties of the compression molding temperature of 230℃ spread carbon fiber composite was superior.