• 한국표면공학회지
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• 제56권3호
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• pp.192-200
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• 2023

Graphene, a two-dimensional material, has shown great potential in a variety of applications including microelectronics, optoelectronics, and graphene-based batteries due to its excellent electronic conductivity. However, the production of large-area, high-quality graphene remains a challenge. In this study, we investigated graphene growth on electrolytic copper foil using thermochemical vapor deposition (TCVD) to achieve a similar level of quality to the cold-rolled copper substrate at a lower cost. The combined effects of pre-annealing time, graphenized temperature, and partial pressure of hydrogen on graphene coverage and domain size were analyzed and correlated with the roughness and crystallographic texture of the copper substrate. Our results show that controlling the crystallographic texture of copper substrates through annealing is an effective way to improve graphene growth properties, which will potentially lead to more efficient and cost-effective graphene production. At a hydrogen partial pressure that is disadvantageous in graphene growth, electrolytic copper had an average size of 8.039 ㎛², whereas rolled copper had a size of 19.092 ㎛², which was a large difference of 42.1% compared to rolled copper. However, at the proper hydrogen partial pressure, electrolytic copper had an average size of 30.279 ㎛² and rolled copper had a size of 32.378 ㎛², showing a much smaller difference of 93.5% than before. This observation suggests this potentially leads the way for more efficient and cost-effective graphene production.

• 실천공학교육논문지
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• 제9권2호
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• pp.139-148
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• 2017

사물과 컴퓨터의 연결이 쉬워지면서 피지컬 컴퓨팅을 활용한 학습은 초보자들을 대상으로 하는 프로그래밍 교육에 있어 제기되는 문제점들을 보완하기 위한 좋은 대안으로 제시되고 있다. 본 논문에서는 초보자들을 위한 기초 프로그래밍 강좌에 적용할 수 있는 교육방법을 제안한다. 이를 위해, 피지컬 컴퓨팅 방식으로 기초 프로그래밍 강의를 진행한다. 현재 피지컬 컴퓨팅 강좌들은 대부분 다양한 입력 센서 연결방법과 출력장치 제어에 초점이 맞추어져 있다. 그러나, 피지컬 컴퓨팅 재료들을 이용한 프로그래밍 교육 내용은 그 사례가 부족하다. 이에 본 논문에서는 피지컬 컴퓨팅에 사용되는 저가의 재료들을 이용하여, 프로그래밍 교육에 활용한 교육 방법을 제안하고 시험하였다.

• 정보교육학회논문지
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• 제15권3호
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• pp.387-397
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• 2011

본 연구에서는 컴퓨터 과학 교육에서 강조하는 알고리즘 수업에서 교육용 프로그래밍 언어인 스크래치를 활용하였을 때 학습자의 논리적 사고력에 미치는 영향을 분석하고자 교재를 개발하고 투입하여 효과를 검증하였다. 알고리즘 교육 내용은 외국의 ACM과 국내의 중학교 정보 교과 교육과정을 분석하여 선정하였으며, 개발된 교재를 초등학교 4학년 학생에게 투입하였다. 논리적 사고력의 영향을 살펴보기 위하여 GALT 축소본 검사지를 사용하였으며 실험집단의 논리적 사고력의 논리합계와 조합논리에서 유의미한 차이의 신장을 보였다.

• 한국표면공학회지
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• 제50권3호
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• pp.164-169
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• 2017

Ni-Cr-X ternary interlayers were investigated to improve the adhesion of Cu/Ni-Cr/Polyimide flexible copper clad laminates. The ternary compounds are sputtered Ni-Cr-X films (where X is one of Nb, V, Mo, or Ti), and the effect of third elements on the adhesion was evaluated and investigated chemically and mechanically. The feel strength was higher in the order of Ni-Cr-Nb > Ni-Cr-V > Ni-Cr > Ni-Cr-Mo > Ni-Cr-Ti. Nb, which has a comparable standard electrode potential to Cr, increased the adhesion, while Ti, with a low standard electrode potential, degraded the adhesion. The Ni-Cr-Nb interlayer was amorphous, while Ni-Cr-Ti was partially crystalline. The similar morphology structure of the Ni-Cr-Nb interlayer with polyimide resulted in a better adhesion.

• 한국분말재료학회지
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• 제27권1호
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• pp.58-62
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• 2020

Recently, electrochromic devices (ECDs) have gathered increasing attention owing to their high color contrast and memory effect, which make them highly applicable to smart windows, auto-dimming mirrors, sensors, etc. Traditional ECDs have a sandwich structure that contains an electrochromic layer between two ITO substrates. These sandwich-type devices are usually fabricated through the lamination of two electrodes and followed by the injection of a liquid electrolyte in the inner space. However, this process is sometimes complex and time consuming. In this study, we fabricated ECDs with a lateral electrode structure that uses only an ITO substrate and an all-in-one electrochromic gel, which is a mixture of electrolyte and electrochromic material. Furthermore, we investigated the EC properties of the lateral-type device by comparing it with a sandwich-type device. The lateral-type ECD shows strong blue absorption as the applied voltage increases and has a competitive coloration efficiency compared to the sandwich-type device.

• 한국콘텐츠학회논문지
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• 제7권10호
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• pp.69-79
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• 2007

현재 초등학교에서는 각 학년에 재량활동 시간을 활용하여 매주 1시간씩 34시간이상을 정보통신기술교육 시간으로 배정하고 있다. 그러나 시대의 변화에 발맞추어 요구되고 있는 창의성과 문제해결력을 키워줄 수 있는 컴퓨터 교재가 개발되어 있지 않아서 시대에 맞는 정보통신기술교육을 하고 있지 못하다. 그리하여 교육인적자원부가 발표한 정보통신기술교육 운영지침을 분석하여 창의성과 문제해결력을 증진시킬 수 있고 현장에서 쓰일 수 있는 5,6학년용 교재를 개발하였다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 추계학술논문집 2부
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• pp.394-397
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• 2011

The effects of heat input(1.4~3.2kJ/mm), shielding gas(Ar80%+$CO_2$20%) and postweld heat treatment(PWHT, $600^{\circ}C$, 40hr.) on the TMCP HSB600 steel weldments made by GMAW process were investigated. The tensile strength and CVN impact energy of as-welded specimens decreased with increasing heat input. The fine-grained acicular ferrite was mainly formed in the low heat input while polygonal and side plate ferrites were dominated in the high inputs. High performance steel for bridges requires higher performance in tensile and yield strength, toughness, weldability, etc. Thus, the purpose of the experiment is to study HSB 600 in GMAW.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.89-90
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• 2006

The CNTs are of great interest because of their unique complete properties of matter, especially, the large thermal conductivity (Thermal conductivity of CNTs ~ >2000W /mK vs. Thermal conductivity of Aluminum ~ >204W/mK). However, owing to the strong agglomeration cause by the vander wall's force, the CNTs are limited to applicate. In this study. we suggest a new method for CNTs dispersion. which are developed by the mechanical and chemical method. and then Cu was coated. This new process produces CNTs/Cu nanocomposite powders. The CNTs are homogeneously located within the Cu powders by chemical reaction. And the thermal properties of the CNTs/Cu nanocomposite were investigated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.148-148
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• 2008

Low-k dielectric materials are an alternative plan to improve the signal propagation delay, crosstalk, dynamic power consumption due to resistance and parasitic capacitance generated the decrease of device size. Now, various materials is studied for the next generation. Diethoxymethlysiliane (DEMS) precursor using this study has two ethoxy groups along with one methyl group attached to the silicon atoms. SiCOH thin films were deposited on p-type Si(100) substrate by Plasma Enhanced Chemical Vapor Deposition (PECVD) using DEMS. In this study, we studied the effect of oxygen($O_2$) flow rate for DEMS to characteristics of thin films. The characteristics of thin films deposited using DEMS and $O_2$ evaluated through refractive index, dielectric constant(k), surface roughness, I-V(MIM:Al / SiCOH / Ag), C-V(MIM), deposition rate.

• 반도체디스플레이기술학회지
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• 제4권4호
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• pp.1-4
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• 2005

The chemical composition and uniaxial compressive stress are varied to observe their effect on the current-voltage characteristics of ZnO based ceramics. The variation of chemical composition produces two kinds of ceramics showing ohmic and nonohmic current-voltage characteristics. The current at a fixed voltage increased with the increase of the compressive stress for both ohmic and nonohmic ceramics. Ceramics showing nonohmic behavior exhibit better reversible return of current-voltage curve when the applied compressive stress is removed from the ceramics than those showing ohmic behavior do. We found an appropriate chemical composition showing linear relation between current and stress at a fixed voltage. The ceramic materials with an appropriate chemical composition can be used as a potential sensing material in pressure sensors.