CNT/PVDF 압전 복합막의 제작과 전기적 특성

이선우,정낙천,Lee, Sunwoo,Jung, Nak-Chun 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.8

The carbon nanotube / poly-vinylidene fluoride (CNT/PVDF) composite films for the nano-generator devices were fabricated by spray coating method using the CNT/PVDF solution, which was prepared by adding PVDF pellets into the CNT dispersed N-Methyl-2-pyrroli-done (NMP) solution. The flexible CNT/PVDF composite films were investigated by the scanning electron microscopy, which revealed that the CNTs were uniformly dispersed in the PVDF matrix and thickness of the films was approximately $20{\mu}m$. Fourier transform infra-red spectra were used to investigate crystal structure of the as-spray-coated CNT/PVDF films, and we found that they revealed extremely large portion of the ${\beta}$ phase PVDF. The capacitance of the CNT/PVDF films increased by adding CNTs into the PVDF matrix, and finally saturated. However, the resistance didn't show any saturation effect in the CNT concentration range of 0~4 wt%. Finally, the resulting nano-generator devices revealed reasonable current output after given mechanical stress.

스프레이 코팅법으로 제조된 CNT/PVDF 압전 복합막의 자기분극 메커니즘

이선우,Lee, Sunwoo 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.7

Carbon nanotubes (CNT) / polyvinylidene fluoride (PVDF) piezoelectric composite films for nanogenerator devices were fabricated by spray coating method. When the CNT/PVDF mixture solution passes through the spray nozzle with small diameter by the compressed nitrogen gas, electric charges are generated in the liquid by a triboelectric effect. Then randomly distributed ${\beta}$ phase PVDF film could be re-oriented by the electric field resulting from the accumulated electrical charges, and might be resulted in extremely one-directionally aligned ${\beta}$ phase PVDF film without additional electric field for poling. X-ray diffraction patterns were used to investigate crystal structure of the CNT/PVDF composite films. It was confirmed that they revealed extremely large portion of the ${\beta}$ phase PVDF crystalline in the film. Therefore we could obtain the poled CNT/PVDF piezoelectric composite films by the spray coating method without additional poling process.

소수성 CNT/PVDF 복합막에서 CNT의 분산과 전도성의 관계

이선우,Lee, Sunwoo 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.7

In this paper, we investigated the relations between dispersion of CNTs (carbon nanotubes) and electrical conductivity in the CNT/PVDF (polyvinylidene fluoride) composite film. By adding hydrophobic CNTs as filler into the PVDF matrix, we fabricated hydrophobic and electrically conducting polymer coating film. Dispersion of CNTs in the CNT/PVDF composite film plays a significant role in terms of electrical conductivity and wetting property. Spray coating method was used to form the CNT/PVDF composite films by injecting the dispersed CNTs in the PVDF solution with different weight ratios from 0.7 wt% to 7 wt%. We investigated the electrical properties and contact angles of the CNT/PVDF composite films with the CNT concentration. Finally we discussed the conducting mechanism and feasibility of the CNT/PVDF composite film for the conducting polymer films.

병렬로 접속된 저항체에서 저항온도계수의 거동

이선우,Lee, Sunwoo 한국전기전자재료학회 2018 전기전자재료학회논문지 Vol.31 No.2

In this paper, we discuss the fabrication of metal alloy resistors. We connected them in parallel to estimate their resistance and temperature coefficient of resistance (TCR). The fabricated resistors have different resistances, 5 and $10{\Omega}$ and different TCRs, 50 and $200ppm/^{\circ}C$. Each resistor was confirmed to have the correct atomic composition through the use of energy dispersive X-ray (EDX). The resistors' electrical properties were confirmed by measuring resistance and TCR. The resistance and TCR of the resistors connected in parallel were estimated through the increase in resistance due to the increase in temperature, and were compared with the measured values. We are confident that this TCR estimation technique, which uses the increase in resistance due to temperature, will be very useful in designing and fabricating resistors with low and stable TCR.

APS로 표면 처리한 Fe 나노 입자 촉매를 이용한 CNT의 직경제어

이선우,Lee, Sunwoo 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.6

Diameter controlled carbon nanotubes (CNTs) were grown using surface modified iron nano-particle catalysts with aminpropyltriethoxysilane (APS). Iron nano-particles were synthesized by thermal decomposition of iron pentacarbonyl-oleic acid complex. Subsequently, APS modification was done using the iron nano-particles synthesized. Agglomeration of the iron nano-particles during the CNT growth process was effectively prevented by the surface modification of nano-particles with the APS. APS plays as a linker material between Fe nano-particles and $SiO_2$ substrate resulting in blocking the migration of nano-particles. APS also formed siliceous material covering the iron nano-particles that prevented the agglomeration of iron nano-particles at the early stages of the CNT growth. Therefore we could obtain the diameter controlled CNTs by blocking agglomeration of the iron nano-particles.

머신 비전 기반 당구공 검출

이선우,허헌,SunWoo Lee,Heon Huh 한국인터넷방송통신학회 2024 한국인터넷방송통신학회 논문지 Vol.24 No.2

Since the outbreak of COVID-19, there has been a surge in sports conducted through online platforms due to the increase in remote and non-contact activities. Billiards, being suitable for online platforms, has received much attention, leading to research on detecting the position and trajectory of balls. In this paper, we propose a new method utilizing machine vision to detect the position of the balls accurately. The proposed method detects the outline of the ball using the Canny edge detection and then employs simple correlation to determine its position. This correlation-based approach offers satisfactory system performance and is easily applicable in practical systems due to its low implementation complexity and robustness to noise.

[발언과 논평] 제로에너지빌딩(ZEB)의 관리와 운영

이선우(Lee, Sunwoo) 대한건축학회 2018 建築 Vol.62 No.7

연금술과 연단술의 유사성 연구

이선우(Sunwoo Lee) 한국동서비교문학학회 2015 동서 비교문학저널 Vol.0 No.33

Alchemy (Western alchemy) and Lian Dan Shu (Chinese alchemy) have lots of similarities though they developed respectively at both ends of Asian Continent. Surveying their historical development aspect, we can find that they started from the fusion of various thoughts and technologies, changed to a skill for transmutation of materials, and finally resulted into the means of mental maturity. They have the common elements in their theories, too. At first, organicism is the common ideological foundation of alchemy and Lian Dan Shu. An alchemical motto, “as above so below” and a maxim of Lian Dan Shu, “heaven and man correspond each other (天人相應)” share the same world outlook. The homologous concepts between the components of each theory, such as, ‘chi (氣)’ and ‘prima materia’, ‘four elements’ and ‘five elements (五行)’ prove that these two theories was almost similar to each other. There is no difference we can actually recognize except the fact that the one pursed the transmutation of gold and the other sought to make jindan (The Golden Elixir, 金丹). Alchemy, which had been thought as a pseudo-science, depending on the development of Modern science which seeks after objectivity, was dramatically reappraised as a guide of ‘collective unconsciousness’ by Karl Gustav Jung. He thought that the alchemical opus was something resembling psychic processes expressed in pseudchemical language and alchemists projected their unconscious into materials with which they experimented. His ‘Individuation’ theory was established through his study of Lian Dan Shu.

장애인직업재활시설의 평가: 문제와 개선 방안

이선우(Lee Sunwoo) 한국직업재활학회 2004 職業再活硏究 Vol.14 No.2

장애인직업재활시설에 대한 평가는 2000년에 이어 2001년에 수행하여 평가 대상인 전체 장애인직업재활시설에 대한 평가를 1차 마무리하였다. 장애인직업재활시설 평가는 직업재활시설의 수준을 높이는데 있어서 중요한 역할을 한다는 것을 보여 주었다. 본 연구에서는 장애인직업재활시설 평가를 개선하기 위해 다음과 같이 제안하였다. 첫째, 프로그램 실시횟수나 실시시간, 프로그램의 내용을 평가하도록 평가기준을 정교 화한다. 둘째, 평가지표를 생산성 중심의 시설과 사회복지서비스 중심의 시설 두 가지로 나누어 평가지표를 따로 개발한다. 셋째, 상설평가원을 설립하여 평가에 대한 신뢰도를 높인다. 넷째, 평가 결과에 대해 적절한 동기부여가 이루어지도록 한다. 이를 위해 정부가 장애인직업재활시설들에게 성공적인 운영을 할 수 있는 기회를 제공해야 한다. Evaluations of Vocational Rehabilitation Facilities for People with Disabilities were carried out in 2000 and 2001 for the first round. The evaluations played an important role in improving the quality of the services provided by the facilities. This study suggests these measures in order to improve the evaluations of Vocational Rehabilitation Facilities for People with Disabilities. First. elaborate evaluative standards counting number and hours of sessions in a program to evaluate it. Second. develop two different evaluative indexes: one for production-oriented facilities and one for social services-oriented facilities. Third. set up a permanent institution for evaluation of Vocational Rehabilitation Facilities. Fourth. motivate the facilities with proper rewards. The governments have to provide Vocational Rehabilitation Facilities for People with Disabilities with opportunities for successful managements.

자가 치유 이온전도체 및 전자소자에서의 응용

이선우(Sunwoo Lee),이해승(Haeseung Lee),강지형(Jiheong Kang) 한국고분자학회 2021 고분자 과학과 기술 Vol.32 No.4