• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.26-32
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• 2021

The photovoltaic properties and microstructure changes were observed while perovskite solar cells (PSCs) with a fabricated carbon electrode were formed using the following annealing processes: hot-plate, oven, and rapid thermal annealing (RTA). Perovskite solar cells with a glass/FTO/compact TiO2/meso TiO2/meso ZrO2/carbon structure were prepared. The photovoltaic properties and microstructure changes in the PSCs were analyzed using a solar simulator, optical microscopy, and field emission scanning electron microscopy. An analysis of the photovoltaic properties revealed outstanding properties when RTA was applied to the cells. Microstructure analysis showed that perovskite was formed locally on the carbon electrode surface when hot-plate and oven annealing were applied. On the other hand, PSC with RTA showed a flat surface without extra perovskite agglomeration. Denser perovskite formed on the porous carbon electrode layer with RTA showed superior photovoltaic properties. These results suggest that the RTA process might be appropriate for the massive production of carbon electrode PSCs considering the processing time.

• Composites Research
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• v.35 no.2
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• pp.86-92
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• 2022

This study was conducted to determine the effect of molecular formation of adhesive on interface characterization of thermoplastic composites. Carbonfiber/polyetherketoneketone (CF/PEKK) thermoplastic composites were fusion bonded and PEEK, PEI adhesive bonded using a high-temperature oven welding process. In addition, lap shear strength test and fracture surface analysis using a digital optical microscope and a scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) were performed. As a result, the adhesive bonding method improved adhesion strength with interphase having increased molecular formation of ether groups, ketone groups, and imide groups which mainly constitutes the CF/PEKK and adhesives. Furthermore, it was found that the use of PEEK containing more ether groups and ketone groups forms a more strongly bonded interphase and enhances the adhesive force of the CF/PEKK composites.

• Journal of Bio-Environment Control
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• v.18 no.1
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• pp.60-66
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• 2009

This study was conducted to investigate into the effective drying method for three greens such as bang-a (Isodon japonicus), aster (Aster yomena) and lettuce greens (Ixeris dentata) Nakai. We have dried three greens using the different drying methods, have made methanol extracts and have also determined the physiological activities in $1,000mg{\cdot}L^{-1}$ extracts. Total phenolic compound contents were most increased by 65.1 and $60.2mg{\cdot}L^{-1}$ in the extracts of bang-a and aster which were frozen dried, however, that in lettuce greens were oven dried by $51.2mg{\cdot}L^{-1}$. Total flavonoid contents were extremely much more in bang-a extracts dried in the oven by $70.6mg{\cdot}L^{-1}$, however, aster and lettuce greens extracts frozen dried by 53.9 and $35.8mg{\cdot}L^{-1}$. DPPH radical scavenging activity in bang-a extracts were greatly increased by 78.8% when bang-a were frozen and dried, however, that in aster were not significant by $89.8{\sim}90.9%$. DPPH radical scavenging activities in lettuce greens extracts were became highest in the order f oven drying (91.9%), natural drying (91.0%) and freeze drying methods (90.9%). Nitrite radical scavenging activities in bang-a and aster extracts were most increased in the natural drying treatment by 73.3 and 78.2%, however, that in lettuce greens extracts were highest in freeze drying treatment by 75.1%.

• Journal of Biosystems Engineering
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• v.22 no.1
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• pp.68-80
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• 1997

마이크로파는 전시중에 레이다로서 널리 이용되어 많은 활약을 하여 왔지만 전쟁이 끝남과 동시에 군용레이다의 수요가 격감하여 마이크로파 전문업체는 레이다를 대신하는 용도로서 가열에 이용하는 것을 고안했다. 1945년 미국의 전문업체에서 마이크로파 도파관의 개구부에 옥수수를 놓았더니 이것이 가열되어 부풀어 터지는 것이 관측되었고 계란의 가열을 시도하였으나 급격한 가열로 파열되어 기술자가 상처를 입은 사고가 발생하였다. 그래서 안전성과 효율향상을 목표로 개방된 공간이 아니라 밀폐된 용기중에 마이크로파를 도입하는 방식이 고안되었다. 이렇게 하여 마이크로파 오븐이 탄생하고 이윽고 그것이 발전하여 가정용의 전자렌지가 되고, 턴넬형의 공업용 가열장치가 되어 고무가류, 식품 등의 건조, 냉동육의 해동 등 널리 실용화되었던 것이다.(중략)

• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.153-160
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• 2000

현장 클레임 데이터는 제품의 불량이 어디에서 발생하는지 그리고 어떻게 개선해야 하는지를 가르쳐 주는 동시에 이를 이용하여 사용환경에서 제품의 신뢰성을 분석할 수 있는 소중한 자료이다. 본 연구에서는 클레임 데이터를 이용한 신뢰성 분석 방법을 바탕으로 주방용 전자기기의 하나인 가스오븐레인지(GOR)의 신뢰성 분석 절차를 구축하고 이를 적용하여 평균수명 등의 신뢰성 관련 제품 특성치를 분석하고자 한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.191-191
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• 2000

마이크로파 절연파괴(breakdown) 및 ECR 플라즈마를 발생시키기 위해 2.45 GHz 마그네트론을 사용하여 간편한 마이크로파 발생장치를 제작하였다. 이 장치는 KAIST-토카막에서 고온 플라즈마를 발생시킬 때 재현성이 좋은 플라즈마를 얻기 위해서 전 이온화하는데 이용된다. 장치에 사용한 마그네트론은 LG 전자의 2M213이고 출력 500W, 주파수 2.45GHz이며, 가정용 전자오븐에 사용된다. 기존의 가정용 마그네트론은 음극(cathode)과 양극(anode)사이에 걸리는 고전압이 60Hz의 주기를 갖기 때문에 약 16ms 마다 8ms동안만 주기적으로 초고주파를 발생한다. 이 마그네트론을 사용하여 연속적으로 발생되는 마이크로파를 얻기 위해서 음극과 양극사이에 개량된 회로로 리플전압이 작은 DC 고전압(5kV, 1A)을 인가하였다. 본 연구에서는 주기적으로 생성.소멸하는 ECR 프라즈마와 연속적인 ECR 플라즈마를 발생시켜 랑뮈어탐침과 광증배관(PMT)을 이용한 H$\alpha$ 방출(emission)을 측정하여 마이크로파 발생장치의 특성을 조사하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.223-226
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• 2004

It is net easy to predict the shrinkage rate of a plastic injection mold in its design process. The shrinkage rate should be considered as one of the important performances to produce the reliable products. The shrinkage rate can be determined by suing the CAE tools in the design produces. However, since the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. In this study, the surrogate models based on the RSM is used in lien of the original models, facilitating design optimization.

• Korean journal of food and cookery science
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• v.10 no.2
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• pp.111-120
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• 1994

본 실험은 4가지의 다른 무게를 가진 고기(0.1kg,0.5kg, 1kg, 1.5kg)를, 3가지의 다른 출력의 전자파(40%, 60%, 100%)로 조리시 나타나는 조리조건(오븐의 효율성, 대기시간, 대기시 상승온도)과 물리 화학적인변화(수분, 단백질, 지방, vit B$_1$,의 함량, 콜라겐의 용해도, 보수력, texture)를 관찰하였다. 고기의 무게가 증가할수록 전자렌지의 효율성은 낮아졌으며, 단위 무게당 조리시간은 고기의 무게가 증가할수록 길어졌다. 화학적 성분들에 있어서는 지방과 콜라겐의 용해도를 제외하고는 처리구간에 유의적인 차이를 보이지 않았다. 지방과 콜라겐의 용해도는 전자파의 출력차이에 의한 유의적인 차이는 나타나지 않았으나, 고기 무게가 증가할수록 지방의 함량의 증가와 콜라겐의 용해도는 증가하였다. Texture를 측정한 항목들에 대해서는 고기의 무게에 따른 유의적인 차이는 나타나지 않았으나 전자파의 출력에 의한 차이를 나타내었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.214-217
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• 2001

Microwave continuous drier system mostly uses the ISM frequency band(915MHz or 2450MHz). It dry the material off from it's inside by the electromagnetic wave. The structure whose openings is needed for dry system to continuously feeds a materials into the system. So it is too difficult to shield the leakage of electromagnetic energy through the apertures. In this paper, we designed microwave continuous drier structure which operates at 2450MHz and analyzed the field distributions at the internal and external region of the structure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.657-660
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• 2005

It is net easy to predict the shrinkage rate of a plastic injection mold in its design process. The shrinkage rate should be considered as one of the important performances to produce the reliable products. The shrinkage rate can be determined by suing the CAE tools in the design produces. However, since the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. Therefore this study was carried out to presume for mutual relation of analysis condition to get the optimum average shrinkage by regression analysis. The results shown that coefficient of determination of regression equation has a fine reliability over 88.3% and regression equation of average shrinkage is made by regression analysis.