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수평형 CVD 장치에서 기판 위치에 따른 단일벽 탄소나노튜브의 합성 수율 및 직경 분포 고찰
조성일(Sung-Il Jo),정구환(Goo-Hwan Jeong) 한국표면공학회 2019 한국표면공학회지 Vol.52 No.6
We investigated a synthesis yield and diameter distribution of single-walled carbon nanotubes (SWNTs) with respect to the growth position in a horizontal chemical vapor deposition (CVD) chamber. Thin films and line-patterned Fe films (0.1 ㎚ thickness) were prepared onto ST-cut quartz substrates as catalyst to compare the growth behavior. The line-patterned samples showed higher growth density and parallel alignment than those of the thin film catalyst samples. In addition, line density of the aligned SWNTs at central region of the chamber was 7.7 tubes/㎛ and increased to 13.9 tubes/㎛ at rear region of the CVD chamber. We expect that the enhanced amount of thermally decomposed feedstock gas may contribute to the growth yield enhancement at the rear region. In addition, the lamina flow in the chamber also contribute to the perfect alignment of the SWNTs based on the value of gas velocity, Reynold number, and Knudsen coefficient we employed.
수중 방전 플라즈마를 이용한 탄소나노소재 합성 시 흑연전극의 형상과 조합의 영향
조성일(Sung-Il Jo),이병주(Byeong-Joo Lee),정구환(Goo-Hwan Jeong) 한국표면공학회 2017 한국표면공학회지 Vol.50 No.2
We investigated the effect of graphite electrode geometry and combination on nanocarbon material synthesis using underwater discharge plasma(UDP). The UDP system consists of two graphite electrodes and beaker filled with de-ionized water. A high voltage of 15 kV with a frequency of 25 kHz is applied to produce UDP using an alternating-current power source. The UDP system with conical electrodes produced the largest amount of products due to the concentration of electrical fields between electrodes. In addition, hollow-shaped stationary electrode and conical-shaped moving electrode stores discharge-induced bubbles and maintains longer reaction time. We found from Raman spectroscopy and electron microscopy that high quality carbon nanomaterials including carbon nanotubes are synthesized by the UDP system.
대기압 플라즈마 제트 시스템을 이용한 문화재 내 세균류 및 진균류의 살균
조성일(Sung-Il Jo),박동민(Dong-Min Park),이병훈(Byeong Hoon Lee),소명기(Myoung-Gi So),하석진(Suk-Jin Ha),정구환(Goo-Hwan Jeong) 한국표면공학회 2020 한국표면공학회지 Vol.53 No.6
Ancient cultural heritage made up of wood and organic fibers have been easily disintegrated or decomposed by various microorganisms like bacteria and fungi. Here, we demonstrate the effectiveness of an atmospheric pressure plasma jet (APPJ) system to sterilize the microorganisms in tangible cultural heritage. We collected several specimens from the surface of ancient documents and wooden artifacts. Finally, two bacteria and two fungi were prepared and sterilized using the APPJ treatment. The APPJ system is beneficial to its simple apparatus, quick operation time, and cost-effectiveness. Bacteria were almost sterilized within only 1 min treatment using 15 % O2 and applied bias voltage of 100 V. In case of the fungi, sterilization rate reached over 83 % but difficult to reach over 90 % even 10 min treatment. According to the plasma diagnostics using optical emission spectroscopy, it was found that the reactive oxygen species such as OH groups are critical for sterilization of microorganisms. Although further efforts should be performed, we believe that efficient sterilization could be realized by the simple, quick, and portable APPJ treatment system.
수평형 유도결합 플라즈마를 이용한 그래핀의 질소 도핑에 대한 연구
조성일(Sung-Il Jo),정구환(Goo-Hwan Jeong) 한국표면공학회 2021 한국표면공학회지 Vol.54 No.6
In this study, optical diagnosis of plasma was performed for nitrogen doping in graphene using a horizontal inductively coupled plasma (ICP) system. Graphene was prepared by mechanical exfoliation and the ICP system using nitrogen gas was ignited for plasma-induced and defect-suppressed nitrogen doping. In order to derive the optimum condition for the doping, plasma power, working pressure, and treatment time were changed. Optical emission spectroscopy (OES) was used as plasma diagnosis method. The Boltzmann plot method was adopted to estimate the electron excitation temperature using obtained OES spectra. Ar ion peaks were interpreted as a reference peak. As a result, the change in the concentration of nitrogen active species and electron excitation temperature depending on process parameters were confirmed. Doping characteristics of graphene were quantitatively evaluated by comparison of intensity ratio of graphite (G)-band to 2-D band, peak position, and shape of G-band in Raman profiles. X-ray photoelectron spectroscopy also revealed the nitrogen doping in graphene.
김상아 ( Kim Sang Ah ),정해원 ( Jeong Hae Won ),한상학 ( Han Sang Hak ),조성일 ( Jo Sung Il ) 한국구조물진단유지관리공학회 2020 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.24 No.1
국내 최초 외부텐던 파단 사례를 통해 실험실 수준의 연구가 아닌 실제 교량을 대상으로 시험하고 검증한 텐던 내부의 광범위한 정밀조사, 구조해석, 보수방안 검증, 비파괴검사법 신뢰도 확인을 통해 텐던 손상 상황별 대처방안을 포함한 보수보강방안 및 유지관리지침을 수립하였다. 또한 텐던 관련 국토교통부의 지침을 개선하기 위해 제도적 잠정안을 마련하여 제안하였으며 『안전점검 및 정밀안전진단 세부지침』개정이라는 성과를 내었다. 특히 실교량에 그라우트 보수방안을 적용하기 전 충진방법 및 MacroCell 부식을 검증하기 위한 시험을 실시하고 텐던 부식 모니터링 시스템을 개발중에 있다. 본 연구의 주요대상은 외부텐던으로 내부텐던 적용 교량의 안전성 확인을 위한 심층적인 추가연구가 필요하다.
청소년의 성격특성에 따른 폭력적인 컴퓨터 게임이 분노표현에 미치는 영향
조순동(Soon Dong Jo),나철(Chul Na),이영식(Young Sik Lee),서동수(Dong Soo Suh),조성일(Sung Il Cho) 대한사회정신의학회 2003 사회정신의학 Vol.8 No.1
목 적: 본 연구는 청소년에서 폭력적인 컴퓨터 게임 전후에 분노표현에서의 차이가 있는지를 알아보고자 한 연구이다. 방 법: 저자들은 80명의 청소년들에게서 폭력적인 컴퓨터 게임 전후에 STAXI(상태-특성 분노 척도, State-trait anger expres-sion inventory)를 각각 측정하였다. 또한 청소년 개개인의 성격특성이 결과에 미치는 영향을 알아보기 위해 MMPI를 시행하 였다. 결 과: 전반적으로 폭력적인 컴퓨터 게임 후에 상태-특성 분노 척도 중에서 내향화된 분노, 분노 조절 척도에서 의미있는 감소를 보였다. 또한 청소년 개개인의 MMPI에서 보인 인격 특성에 따라 서로 상반된 결과가 나왔다. 즉 D 척도가 낮고 Pd 척도가 높으며 Si 척도가 높은 군은 분노표현이 증가하였으나, 반대로 D 척도가 높고 Pd 척도가 낮으며 Si 척도가 낮은 군은 분노표현이 감소하였다. 결 론: 이번 연구로 폭력적인 컴퓨터 게임으로 인해서 분노 감정의 표출의 증가를 가져온다는 것을 알 수 있었다. 하지만 모든 청소년 에게 이러한 변화의 경향이나 방향이 일치되는 결과를 보이지는 않았고 각자의 성격 특성에 따라 차이가 있는 것이 확인되었다. Objective:The purpose of this study was to evaluate the change of anger expression in adolescents after playing violent computer game. Method:We compared STAXI(State-trait anger expression inventory) of pre- to post-playing violent computer game about 80 adolescents. Subjects were assessed with MMPI to evaluate the influence of character traits to the results. Result:After playing violent computer game, anger-in and anger-control subscale scores decreased. Association with subscales of MMPI, in high D subscale group, anger-in subscale scores decreased and in low D subscale group, they increased. In high Pd subscale group, anger-out subscale scores decreased and in low Pd subscale group, they increased. In high Si subscale group, anger-in and anger-control subscale scores decreased but in low Si subscale group, they increased. Conclusion:We found that the violent computer game was significantly related to the change of anger expression in adolescents and the change of anger expression was influenced by the adolescents' individual character traits.
열전도성 점착제 응용을 위한 고분자 기반 탄소나노소재 복합체 제조 및 특성 평가
이병주(Byeong-Joo Lee),조성일(Sung-Il Jo),윤은혜(Eun-Hye Yoon),이애리(Ae-Ri Lee),이우영(Woo-Young Lee),허성규(Sung-Gyu Heo),황재성(Jae-Sung Hwang),정구환(Goo-Hwan Jeong) 한국표면공학회 2020 한국표면공학회지 Vol.53 No.4
A polymer-based carbon nanomaterial composite was fabricated and characterized for the application of a thermal conductive adhesive. Low-dimensional carbon nanomaterials with excellent thermal conductivity such as carbon nanotube (CNT) and graphene were selected as a filler in the composite. Thermal, electrical and adhesive properties of the composite were investigated with respect to the morphology and content of the low-dimensional carbon nanomaterials. As a result, the composite-based adhesive fabricated by the loading of surface-treated MWCNTs of 0.4 wt% showed uniform dispersion, moderate adhesion and effective heat dissipation properties. Finally, it was confirmed through the thermal image analysis of LED module that the temperature reduction of 10°C was achieved using the fabricated composite adhesive with MWCNT-6A. Expecially, heat dissipation performance of the optimized composite adhesive was evident at the hot spot in the module compared to other samples mixed with graphene or different MWCNT loading ratios.