• 한국세라믹학회지
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• 제38권1호
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• pp.45-51
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• 2001

고체산화물 연료전지의 삼상 계면의 길이를 증가시키기 위해 Glycine-Nitrate Process(GNP)를 이용하여 환원극 재료인 L $a_{0.5}$S $r_{0.5}$Mn $O_3$(LSM)과 전해질 재료인 C $e_{0.8}$G $d_{0.2}$ $O_{1.9}$(CGO)를 합성하였다. 적당한 합성조건을 찾기 위하여 글리신의 양을 달리하여 분말을 합성한 결과 LSM의 경우 글리신이 양이온 몰수의 2배일 때 perovskite상이 얻어졌으며 비표면적은 34$m^2$/g 이었다. 합성된 LSM과 CGO 분말을 50:50 wt%로 혼합하여 제작된 환원극을 screen-printing법으로 코팅한 후 각각 1200, 1300, 1350 및 140$0^{\circ}C$에서 4시간 동안 소결한 후 80$0^{\circ}C$에서 power density와 양극과전압 등을 측정한 결과 130$0^{\circ}C$에서 소결한 단위전지에서 최대 309 mW/$ extrm{cm}^2$의 power density를 얻을 수 있었다.다.

• 한국포장학회지
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• 제30권1호
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• pp.73-83
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• 2024

In this study, environmental evaluation of high barrier coated paper (coating layer/paper) packaging is conducted in comparison with conventional aluminum laminated (PET/VMPET/LLDPE) plastic packaging. The target product for this packaging is a KF94 mask, which requires a high barrier of water and oxygen to maintain the filtration ability of the mask filter. The functional unit of this study is 10,000 mask packaging materials based on a material capable of blocking oxygen (<1 g/m²day) and moisture (<3 g/m²day) for the preservation of KF94 masks. In order to understand the results easily, paper-based mask packaging system divided into 6 stages (pulp, pulping & paper making, calendaring & coating, printing, packing and waste management), while plastic-based mask packaging consists of 5 stages (material production, processing, printing, packing, waste management) In case of paper-based mask packaging, most contributing stage is calendaring & coating, resulting from heat and electricity production. On the other hand, plastic-based mask packaging is contributed more than 30% by material production, specifically due to linear low density polyethylene and purified terephthalic acid production. The comparison results show that global warming potential of paper-based mask packaging has 32% lower than that of plastic-based mask packaging. Most of other impact indicators revealed in similar trend.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1824-1826
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• 1999

In order to develop key technologies for a kW class for polymer electrolyte fuel cell (PEFC), various membranes (Nafion(112, 115, 117), Dow, Flemion, Gore, and Hanwha), and electrocatalysts (Pt/C, PtNi/C PtNiCo/C and PtRu/C) were used in the fabrication of the MEAs by using transfer printing technique. The effects of the thickness of Nafion membranes, electrocatalysts and the operating conditions (e.g. temperature, reactant gas pressure, and composition) on the performance of the MEA were investigated in the PEFC single cell($O_2/H_2$, and Air/$H_2$ cell). The performances of the MEAs for $O_2/H_2$ and Air/$H_2$ cells has been evaluated.

• 한국재료학회지
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• 제14권9호
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• pp.670-675
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• 2004

Glasses in the $Bi_{2}O_3-SiO_2-ZnO$ glasses system were examined as a potential replacement for lead-oxide glass frits with low firing temperature ($500\sim600^{\circ}C$) for the dielectric layer of a plasma display panel (PDP). The glasses were evaluated for glass transition temperature($T_{g}$) and thermal expansion coefficient(${\alpha}$). After forming transparent thick films by a screen-printing method, it was evaluated for the optical properties. The transmittance of thick films fired at $500-600^{\circ}C$ showed above $80\%$, which was not dependent on the firing temperature. As a result, many pores were observed at samples fired at low temperature, while the number of pores from samples prepared at high temperature decreased and the pores size increased.

• 한국방사선학회논문지
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• 제16권3호
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• pp.225-231
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• 2022

4차 산업혁명시대 최신 기술을 통해 공간 및 시간의 초월, 가상현실, 증강 현실 등이 구현되고 있다. 현재 인공지능, 증강현실, 빅데이터 등을 경험하고 있는 상황에서 방사선과 재학생들을 대상으로 4차 산업혁명 최신 기술에 대한 관심도와 4차 산업혁명시대 필요한 역량, 4차 산업혁명시대 방사선분야 채용 환경의 전망에 대한 인식도를 알아보고자 하였다. 2022년 2월 7일부터 2월 18일까지 대구시 소재 S대학교 방사선과 재학생 2, 3학년을 대상으로 설문지를 이용하여 인식도 조사를 분석하였다. 연구결과 3D 모델링 관심도가 평균 3.34 ± 1.09점으로 가장 높게 나타났으며, 빅데이터와 인공지능에 대해서도 보통 이상 3.27 ± 1.17, 3.33 ± 1.07점으로 관심을 보이고 있었다. 또한, 4차 산업혁명시대 필요한 역량 인식도와 4차 산업혁명시대 방사선분야 채용 환경 전망 인식도 간 상관성이 가장 높았으며(r=0.778, p<0.01), 4차 산업혁명 최신 기술 관심도와 4차 산업혁명시대 필요한 역량 인식도 간에도 상관성이 있음을 알 수 있었다(r=0.694, p<0.01). 4차 산업 혁명시대 3D프린팅, 인공지능, 빅데이터 등의 최신 기술을 다룰 수 있는 전문 교육 강화, 방사선 의료기술분야에서의 최신 기술과 관련된 취업역량 강화를 위한 교육이 필요할 것으로 판단된다.

• 한국의학물리학회지:의학물리
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• 제28권3호
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• pp.100-105
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• 2017

The purpose of the present study was to develop and evaluate patient-customized helmets with a three-dimensional (3D) printer for radiation therapy of malignant scalp tumors. Computed tomography was performed in a case an Alderson RANDO phantom without bolus (Non_Bolus), in a case with a dental wax bolus on the scalp (Wax_Bolus), and in a case with a patient-customized helmet fabricated using a 3D printer (3D Printing_Bolus); treatment plans for each of the 3 cases were compared. When wax bolus was used to fabricate a bolus, a drier was used to apply heat to the bolus to make the helmet. $3-matic^{(R)}$ (Materialise) was used for modeling and polyamide 12 (PA-12) was used as a material, 3D Printing bolus was fabricated using a HP JET Fusion 3D 4200. The average Hounsfield Unit (HU) for the Wax_Bolus was -100, and that of the 3D Printing_Bolus was -10. The average radiation doses to the normal brain with the Non_Bolus, Wax_Bolus, and 3D Printing_Bolus methods were 36.3%, 40.2%, and 36.9%, and the minimum radiation dose were 0.9%, 1.6%, 1.4%, respectively. The organs at risk dose were not significantly difference. However, the 95% radiation doses into the planning target volume (PTV) were 61.85%, 94.53%, and 97.82%, and the minimum doses were 0%, 77.1%, and 82.8%, respectively. The technique used to fabricate patient-customized helmets with a 3D printer for radiation therapy of malignant scalp tumors is highly useful, and is expected to accurately deliver doses by reducing the air gap between the patient and bolus.

• 한국산학기술학회논문지
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• 제22권2호
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• pp.632-637
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• 2021

현재 미래의 건설 산업 기술을 발전시키고자 최근 미래 산업으로 각광받고있는 3D 프린팅을 이용한 콘크리트의 시공기술을 활용하여 구조물을 건설하는 연구가 국내외 건설업계 및 학계에서 활발히 진행되고 있다. 하지만 현재 개발되고 있는 3D 프린팅 기술은 적합한 시공기술, 콘크리트 재료 자체의 물성이 사용기준에 미치지 못하고 실제 현장에서 적용하기가 어려운 상황이다. 또한 시공된 구조물에 대한 내구성 관리 및 유지관리를 위한 연구가 필요한 실정이다. 본 연구에서는 Material extrusion 방식으로 출력한 3D 프린팅 콘크리트를 각각의 적층 방향 X, Y, Z축으로 나누어 측정한 압축강도와 휨강도를 기존의 몰드에 제작한 시험체와 비교 분석하였다. Test direction II Z축의 시험체의 압축강도가 나머지 Test direction I, III Y축, X축의 시험체에 비하여 8~10%의 높은 강도를 발현하였고 몰드 제작 시험체와 비교하였을 경우 4%가량 낮은 강도를 발현하였다. 휨강도 측정결과 재령 28일 기준으로 Test direction II Z축 방향의 시험체의 휨강도가 Test direction I, III Y축, X축의 시험체에 비하여 5~7%의 높은 강도를 발현하였고 몰드 제작 시험체와 비교하였을 경우 2%가량 낮은 강도를 나타내었다.

• 품질경영학회지
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• 제42권2호
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• pp.145-152
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• 2014

Purpose: As the number of people directly employed in making things declines, the cost of labour as a proportion of the cost of production and delivery will diminish too. This will make to move the focus of quality management because new manufacturing techniques make it cheaper and faster to respond to changing local tastes Methods: This discussion is induced by understanding that change the point of view of quality. Results: Mark-processing method using a mold of 3D-printer is different from traditional manufacturing methods. Design, rapid prototyping of products produced by the right way, many changes in many industries will be created. Therefore, the design will be more emphasis on the importance of quality. Conclusion: As manufacturing goes digital, a Quality great change is now gathering pace. It will allow things to be made economically in much smaller numbers, more flexibly and with a much lower input of labour, thanks to new materials, completely new processes such as 3D printing. So we must change the vantage point of quality, from process to Design, R&D, and Delivery.

• 한국산학기술학회논문지
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• 제12권1호
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• pp.15-18
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• 2011

현재까지 제품의 표면 질감을 얻기 위해 단순히 도장과 인쇄 같은 방법으로 2차원적인 표면처리 공정을 이용해 왔다. 그러나 밀리 스케일의 자연물 표면에 마이크로 스케일의 3차원 표면 구조를 성형해야만 보다 자연물과 유사한 질감을 얻을 수 있을 것이다. 본 논문에서는 이와 같은 3차원 표면 구조를 가지는 사출성형품을 제작하기 위해 전주 기술을 이용한 자연물 표면 복제 기술, 전주에 의해 제작된 평면 stamper를 제품 표면 형상과 같은 곡면으로 제작하는 프레스 기술, 곡면의 stamper를 장착하여 사출 성형할 수 있는 금형 및 성형 기술을 개발하여 3차원 질감을 가지는 스마트폰 케이스를 제작하였다.

• Environmental Analysis Health and Toxicology
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• 제18권3호
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• pp.219-224
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• 2003

1,4-Dioxane is used as a solvent for lacquers, paints, varnish removers, dye baths and printing compositions. And it is also used for detergent preparations, cosmetics, deodorants and fumigants. A method is described for the determination of 1,4-dioxane in water samples by GC/MS. The extraction recoveries were studied for some solvents and solvent volume ratio were investigated using r-butyl methyl ether (MTBE). Optimum condition was obtained by the liquid-liquid extraction using the 10 mL of MTBE for 10 mL of water. Method detection limit of 1,4-dioxane in the 20 mL of water samples was 0.05 ng/mL. It could be determined in the range of 0.24∼240 ng/mL in treated water, and in the range of 0.69∼81.9 ng/mL in raw water, respectively. Risk assessments with 1,4-dioxane exposure by drinking water ingestion were carried out. Based on the results of analysis, chronic daily intake of 1,4-dioxane was 2.22${\times}$10$\^$-4/ mg/kg/day and excess cancer risk was calcu-lated to be 2.44${\times}$10$\^$-6/.