• 적정기술학회지
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• 제6권2호
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• pp.226-237
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• 2020

As the number of reported COVID-19 cases rises around the world, regions affected by the virus are taking serious measures to contain its spread. Face shields are one of the highest-need personal protective equipment (PPE) during COVID-19 pandemic. Beyond traditional face masks, as known cases of the coronavirus soar, currently there is a significant shortage of face shields around the world. In response, the protective face shields were designed and fabricated with open-source 3D modelling software and 3D printing technology, respectively. Our face shield consisted of two parts only; a reusable 3D printed headband and a visor made of transparent plastic sheet, as barrier. The resulting 3D printed face shields are affordable, lightweight, one-size-fits-most and ready-to-wear with minimal assemblies, and go on easily over glass, goggle and face mask. To ensure being donated to the healthcare professionals without risk infected by any pathogens, the 3D printed face shields were successfully be disinfected with ultraviolet germicidal irradiation (UVGI dosage of 1000 mJ/cm²) and 70% alcohol. For routine disinfection a UVGI chamber was designed and optimized to provide uniform UV-C illumination with an appreciated fluence for complete decontamination. More than 1,000 face shields were produced already and donated to the special hospitals for COVID-19 patients, quarantines, government and medical agencies in Ethiopia as well as in East-African countries. With certainty, our intention goes beyond the hospitals and other first responders, but not limited for all those who have to stay in the service or be in contact with many other people in the time of COVID-19 pandemic.

• 한국염색가공학회지
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• 제33권4호
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• pp.210-219
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• 2021

It was intended to conduct basic research to reduce development lead time and cost consumed in DTP process technology development. For the simulation of HTPE fabric, virtual engineering software was used to generate fiber model, yarn model, fabric model, and finite element model of HTPE fiber. The purpose of this study is to analyze the correlation and error rate between the stiffness numerical analysis results according to the direct DTP process parameters using reactive dyes in the generated finite element model and the stiffness measurements of the actual sample ac- cording to ASTM D1388. And, after dyeing the HTPE plain fabric according to the direct DTP process parameters, we want to analyze the dyeability of the HTPE fabric fabrics according to the direct DTP process parameters through the color fastness analysis. When looking at the results of the analysis of the finite element model, a higher value was shown when the distance between the nozzle and the fabric was 3mm than when the distance was 10mm. When the distance between the nozzle and the fabric was 10mm and 7mm, the reactive dye did not penetrate sufficiently, resulting in poor clarity when viewed with the naked eye.

• Tribology and Lubricants
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• 제39권1호
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• pp.1-7
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• 2023

Fluid pumps in chemical processes are typically driven by electric motors. Even if the motor is separated from the pump with seals, wear resulting from friction and misalignment can lead to leakage of chemical fluid, causing corrosion in the bearing supporting the motor, and, eventually, failure of the motor. It is thus a standard procedure to replace bearings at regular intervals. In this article, we propose 3D-printed plastic ball bearings for use as an alternative to commercial stainless-steel ball bearings. The plastic bearings are easy to manufacture, require less time to replace, and are chemically resistant. To validate the applicability of the plastic bearings, we first conducted chemical resistance tests. Bearings were immersed in 30 caustic acid and 30 nitric acid for 30 min and 24 h, respectively. The test results showed no corrosive damage to the bearings. A test rig was set up to compare the performance of the plastic bearings with that of the commercially equivalent deep-groove ball bearings. Loading test results showed that the plastic bearings performed as well as the commercial bearing in terms of vibration level and load-handling capability. Finally, a plastic bearing was subjected to a clean-in-place process for three months. It actually outperformed the commercial bearing in terms of chemical resistance. Thus, 3D-printed plastic bearings are a viable alternative to stainless-steel ball bearings.

• 한국응용과학기술학회지
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• 제40권1호
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• pp.71-80
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• 2023

실버 페이스트는 상대적으로 낮은 열처리로 공정이 가능하기 때문에 전자 소자 응용분야에서 유용한 전극 재료이다. 본 연구에서는 은 페이스트 전극에 대기압 플라즈마 제트를 이용하여 전극 표면을 처리 했다. 이 플라즈마 제트는 11.5 kHz 작동 주파수에서 5.5 ~ 6.5 kV의 고전압을 사용하여 아르곤 분위기에서 생성되었다. 플라즈마 제트는 대기압에서 수행함으로써 인쇄 공정에 더 유용할 수 있다. 플라즈마 처리시간, 인가된 전압, 가스유량에 따라 전극의 표면은 빠르게 친수성화 되었으며 접촉각의 변화가 관찰되었다. 또한, 대면적 샘플에서 플라즈마 처리 후 접촉각의 편차가 없었는데, 이는 기판의 크기에 관계없이 균일한 결과를 얻을 수 있었다는 것을 의미한다. 본 연구의 결과는 대면적 전자소자의 제조 및 향후 응용 분야에서 적층 구조를 형성하는데 매우 유용할 것으로 기대된다.

• 멤브레인
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• 제32권1호
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• pp.33-42
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• 2022

성장하는 산업화는 심각한 수질 오염으로 이어진다. 폐수로 배출되는 약품과 섬유산업에서 나오는 유기배출물은 환경과 생명에게 악영향을 미친다. 항균치료에 사용되는 항생제가 폐수에 존재하면 인체에 매우 해로운 약제 내성균의 성장을 야기하게 된다. 섬유산업에서 사용되는 유기염료 분자의 제조에는 다양한 유기 저분자가 사용된다. 이러한 분자들은 인쇄 및 염색 산업의 폐수 배출물에 존재하여 분해가 잘 이루지지 않는다. 이러한 문제들을 해결하기 위해 광분해성 촉매를 분리막에 도입하고 폐수를 처리한다. 이 과정을 통해 유기 분자는 광분해되며 동시에 분해된 화합물들은 분리막을 통과하여 분리된다. 이산화티타늄(TiO₂)은 뛰어난 광촉매 역할을 하는 반도체이다. 다른 전이 금속 산화물과 화합물을 만들고 고분자 막에 도입하여 광촉매 능력을 증가시킨다. 본 총설에서는 광촉매성 분리막에 의한 염료 및 약물 분자의 분해에 대해 논의한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.328-329
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• 2021

최근 제4차 산업혁명은 21세기 초부터 정보통신기술 융합기반의 초지능, 초연결 산업혁명으로 디지털 기술과 물리적, 생물학적 기술 사이의 경계가 사라지면서 융합되어 나타나는 기술혁신으로 정의되다. 디지털 기술 분야에서는 인공지능, 사물인터넷 그리고 블록체인 기술을 포함하고 있다. 물리학 기술 분야에는 로봇공학, 무인운송수단과 3D 프린팅 기술을 언급하였다. 생물학 기술 분야에서는 생명공학 및 나노기술을 두각을 나타낼 것이라고 말했다. 2016년 1월 스위스 다보스에서 개최된 세계경제포럼에서 회장인 슈밥(Klaus Schwab) 교수가 처음으로 제4차 산업혁명을 제안하였다. AHP(analytic hierarchy process) 분석기법을 적용하기 위해 1단계 요인으로 자원, 물, 지구 그리고 원자로 구분하였다. 또한 2단계 요인으로는 개념모델에서 제시된 9개 세부 에너지로 조직하였다. 따라서 분석결과를 바탕으로 연구의 한계와 이론적 실무적 시사점을 제시하고자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.330-331
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• 2021

최근 제4차 산업혁명은 21세기 초부터 정보통신기술 융합기반의 초지능, 초연결 산업혁명으로 디지털 기술과 물리적, 생물학적 기술 사이의 경계가 사라지면서 융합되어 나타나는 기술혁신으로 정의되다. 디지털 기술 분야에서는 인공지능, 사물인터넷 그리고 블록체인 기술을 포함하고 있다. 물리학 기술 분야에는 로봇공학, 무인운송수단과 3D 프린팅 기술을 언급하였다. 생물학 기술 분야에서는 생명공학 및 나노기술을 두각을 나타낼 것이라고 말했다. 2016년 1월 스위스 다보스에서 개최된 세계경제포럼에서 회장인 슈밥(Klaus Schwab) 교수가 처음으로 제4차 산업혁명을 제안하였다. AHP(analytic hierarchy process) 분석기법을 적용하기 위해 1단계 요인으로는 디지털기술, 물리학기술 그리고 생물학기술으로 설계하였다. 또한 2단계 요인으로는 개념모델에서 제시된 8개 세부 서비스로 조직하였다. 따라서 분석 결과를 바탕으로 연구의 한계와 이론적 실무적 시사점을 제시하고자 한다.

• 한국지형학회지
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• 제28권1호
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• pp.101-114
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• 2021

Junior Ranger is a self-directed interpretation program for young visitors at national parks in the United States. The success of this program can be largely attributed to the role of an activity book which is given an applicant free of charge at a visitor center. This study aims to analyze the main characteristics of activity books for 14 national parks' Junior Ranger and to draw some implications for Korean geomorphological education. Although the activity books are varied in size, volume and printing, all of them offer diverse activities which are composed of different contents related to park resources in four fields and are performed in different ways such as Q&A, picture and word game, and creative activity. The time-consuming activities including attendance at a ranger-led program prevent the participant from making a superficial visit to be a junior ranger. The implications of the study are as follows: Firstly, the geomorphological education for children is needed to be strongly based on field experience learning and to be more carried out using a way of game rather than conventional Q&A, suggesting that it encourages students not to lose their interest for learning. Secondly, it is also necessary for the learning contents to be focused on various resources related to landform as well as landform itself. In addition, a creative activity such as writing verse or drawing feeling should be more applied to the geomorphological education in order to enhance their effects on affective domain beyond cognitive one. It is likely to be an alternative approach to understand landform by internalizing a sense of landform.

• 한국전기전자재료학회논문지
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• 제36권6호
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• pp.588-593
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• 2023

The advantage of OTFT technology is that large-area circuits can be manufactured on flexible substrates using a low-cost solution process such as inkjet printing. Compared to silicon-based inorganic semiconductor processes, the process temperature is lower and the process time is shorter, so it can be widely applied to fields that do not require high electron mobility. Materials that have utility as electrode materials include carbon that can be solution-processed, transparent carbon thin films, and metallic nanoparticles, etc. are being studied. Recently, a technology has been developed to facilitate charge injection by coating the surface of the Al electrode with solution-processable titanium oxide (TiOx), which can greatly improve the performance of OTFT. In order to commercialize OTFT technology, an appropriate method is to use a complementary circuit with excellent reliability and stability. For this, insulators and channel semiconductors using organic materials must have stability in the air. In this study, carbon-doped Mo (MoC) thin films were fabricated with different graphite target power densities via unbalanced magnetron sputtering (UBM). The influence of graphite target power density on the structural, surface area, physical, and electrical properties of MoC films was investigated. MoC thin films deposited by the unbalanced magnetron sputtering method exhibited a smooth and uniform surface. However, as the graphite target power density increased, the rms surface roughness of the MoC film increased, and the hardness and elastic modulus of the MoC thin film increased. Additionally, as the graphite target power density increased, the resistivity value of the MoC film increased. In the performance of an organic thin film transistor using a MoC gate electrode, the carrier mobility, threshold voltage, and drain current on/off ratio (I_on/I_off) showed 0.15 cm²/V·s, -5.6 V, and 7.5×10⁴, respectively.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.154-160
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• 2023

Recently, with the activation of eBook services, books are being published simultaneously as physical books and digitized eBooks. Paper books are more expensive than e-books due to printing and distribution costs, so demand for relatively inexpensive e-books is increasing. There are cases where previously published physical books cannot be digitized due to the circumstances of the publisher or author, so there is a movement among individual users to digitize books that have been published for a long time. However, existing research has only studied the advancement of the pre-processing process that can improve text recognition before applying OCR technology, and there are limitations to digitization depending on the condition of the book. Therefore, support for book digitization services depending on the condition of the physical book is needed. need. In this paper, we propose a method to support digitalization services according to the status of physical books held by book owners. Create images by scanning books and extract text information from the images through OCR. We propose a method to recover text that cannot be extracted depending on the state of the book using BERT, a natural language processing deep learning model. As a result, it was confirmed that the recovery method using BERT is superior when compared to RNN, which is widely used in recommendation technology.