• 콘크리트학회논문집
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• 제25권6호
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• pp.667-674
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• 2013

기존 강재 브레이싱 내진보강법은 정착부의 안정성 문제와 브레이싱의 국부좌굴이 발생할 문제가 있으며, 이를 방지하기 위한 추가보강으로 인해 불필요한 자중증가 등으로 경제적인 내진보강성능 확보에 어려움이 있다. 이 연구에서는 지진피해를 받은 건물에 지진피해로 인한 기존 기둥의 연성확보를 위해서 유리섬유시트(glass fiber sheet)로 래핑을 함과 동시에 기존 철골 X-브레이싱 내진보강법에 비교해서 경량의 고강도 재료로 보강 후 추가적인 중량증가가 거의 없으며, 브레이싱 압축 좌굴거동에 자유로운 탄소섬유 앵커 X-브레이싱공법(carbon fiber X-brace)을 조합한 경제적이며 효과적인 새로운 내진보강법(GFS-CFXB)을 제안하였다. 이 연구에서 제안한 GFS-CFXB공법의 유용성을 검증할 목적으로 지진피해를 받은 골조를 대상으로 반복가력에 의한 구조실험을 실시하여 내진성능 및 내진보강 효과를 검증하였다.

• Advanced Composite Materials
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• 제18권3호
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• pp.209-219
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• 2009

Carbon nanotubes (CNTs) have shown great potential for the reinforcement of polymers or fiber-reinforced composites. In this study, mechanical properties of multi-walled carbon nanotube (MWNT)-filled plain-weave glass/epoxy composites intended for use in radar absorbing structures were evaluated with regard to filler loading, microstructure, and fiber volume fraction. The plain-weave composites containing MWNTs exhibited improved matrix-dominant and interlaminar fracture-related properties, that is, compressive and interlaminar shear strength. This is attributed to strengthening of the matrix rich region and the interface between glass yarns by the MWNTs. However, tensile properties were only slightly affected by the addition of MWNTs, as they are fiber-dominant properties.

• 한국전기전자재료학회논문지
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• 제24권3호
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• pp.245-249
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• 2011

Carbon nanotubes (CNTs) have been significantly used for the field emitters for display applications. However, the lifetime of CNT emitters which are formed by screen printing technique is not guaranteed yet, because the constituents in CNT paste affect the lifetime of CNTs. The CNT pastes for screen printing are normally composed of organic vehicles (nitro cellulose, ethyl cellulose, etc) and additives (glass frits, indium tin oxide (ITO), etc) with CNTs. In this study, the effects of constituents in CNT pastes on the lifetime and emission characteristics of CNTs were investigated by thermal and electrical analysis. Use of glass frits worsened the lifetime and electron emission of CNTs. However, an addition of ITO to CNT paste rather improved the lifetime of CNTs. Degradation of CNTs was small when nitro cellulose was used in CNT paste as an organic vehicle.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.408-410
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• 2012

본 연구에서는 수지 인장시편과 스트랜드 인장시편을 적용하여 탄소섬유/에폭시 복합재의 고온에서의 특성을 조사하였다. 연구결과에 따르면 수지시편의 인장강성은 수지의 유리전이 온도에 근접해감에 따라 서서히 감소하지만 스트랜드 인장시편의 인장강성은 상온에서의 인장강성을 유지한다. 수지시편과 스트랜드 시편의 인장강도는 온도가 유리전이 온도에 근접할수록 급격한 감소를 나타내었다.

• Structural Engineering and Mechanics
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• 제85권5호
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• pp.573-592
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• 2023

This paper presents a careful theoretical investigation into interfacial stresses in composite aluminum-slab reinforced concrete beam bonded by a prestressed hybrid carbon-glass composite material. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the aluminum beam, the slab reinforced concrete, the hybrid carbon-glass composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of interfacial stress distributions. It is shown that the stresses at the interface are influenced by the material and geometry parameters of the composite beam. This research is helpful for the understanding on mechanical behaviour of the interface and design of the hybrid structures.

• Journal of the Korean Wood Science and Technology
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• 제39권2호
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• pp.156-162
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• 2011

To evaluate the bonding performance of reinforced glulam, the textile type of glass fiber and aramid fiber, and the sheet type of glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP) were used as reinforcements. The reinforced glulam was manufactured by inserting reinforcement between the outmost and middle lamination of 5ply glulam. The types of adhesives used in this study were polyvinyl acetate resins (MPU500H, and MPU600H), polyurethane resin and resorcinol resin. The block shear strengths of the textile type in glass fiber reinforced glulam using MPU500H and resorcinol resin were higher than 7.1 N/$mm^2$, and these glulams passed the wood failure requirement of Korean standards (KS). In case of the sheet types, GFRP reinforced glulams using MPU500H, polyurethane resin and resorcinol resin, and CFRP reinforced glulams using MPU500H and polyurethane resin passed the requirement of KS. The textile type of glass fiber reinforced glulam using resorcinol resin after water and boiling water soaking passed the delamination requirement of KS. The only GFRP reinforced glulam using MPU500H after water soaking passed the delamination requirement of KS. We conclude that the bonding properties of adhesive according to reinforcements are one of the prime factors to determine the bonding performance of the reinforced glulam.

• Carbon letters
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• 제12권2호
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• pp.90-94
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• 2011

We present the effect of a coupling agent on the optoelectrical properties of few-walled carbon nanotube (FWCNT)/epoxy resin hybrid films fabricated on glass substrates. The FWCNT/epoxy resin mixture solution was successfully prepared by the direct mixing of a $HNO_3$-treated FWCNT solution and epoxy resin. FWCNT/binder hybrid films containing different amounts of the coupling agent were then fabricated on UV-ozone-treated glass substrates. To determine the critical binder content ($X_c$), the effects of varying the binder content in the FWCNT/silane hybrid films on their optoelectrical properties were investigated. In this system, the $X_c$ value was approximately 75 wt%. It was found that above $X_c$, the coupling agent effectively decreased the sheet resistance of the films. From microscopy images, it was observed that by adding the coupling agent, more uniform FWCNT/binder films were formed.

• 한국광학회지
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• 제18권5호
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• pp.362-366
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• 2007

본 연구에서는 3 메가픽셀, 2.5배 줌 카메라폰 모듈용 비구면 유리렌즈 개발을 목적으로 실험계획법(DOE)을 적용하여 성형용 초경 코어의 연삭가공조건을 구하고, 이를 활용하여 비구면 Glass렌즈 성형용 초경합금(WC) 코어를 초정밀 연삭가공을 수행하였다. 또한 가공된 성형용 코어의 가공면 위에 이온증착법으로 다이아몬드상 탄소(Diamond-Like Carbon; DLC) 코팅을 수행하여 DLC 코팅이 성형용 코어의 형상정도(PV)와 표면조도(Ra)에 미치는 영향을 평가하였으며, 비구면 Glass렌즈를 동일한 조건에서 성형하여 성형렌즈의 광학적 특성을 비교하여 성형용 코어면의 DLC 코팅 효과에 대하여 검토하였다.

• 한국재료학회지
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• 제25권7호
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• pp.341-346
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• 2015

The feasibility of obtaining graphitic carbon films on targeted substrates without a catalyst and transfer step was explored through the pyrolysis of the botanical derivative camphor. In a horizontal quartz tube, camphor was subjected to a sequential process of evaporation and thermal decomposition; then, the decomposed product was deposited on a glass substrate. Analysis of the Raman spectra suggest that the deposited film is related to unintentionally doped graphitic carbon containing some $sp-sp^2$ linear carbon chains. The films were transparent in the visible range and electrically conductive, with a sheet resistance comparable to that of graphene. It was also demonstrated that graphitic films with similar properties can be reproduciblyobtained, while property control was readily achieved by varying the process temperature.

• Journal of Welding and Joining
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• 제34권2호
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• pp.22-29
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• 2016

Recently, Application of composite materials are increased in transport area for weight reduction. Also, Related technical developments have been implemented actively at domestic and abroad. In particular, The carbon fiber has high strength and ultra light property higher than stainless steel, aluminum, GFRP as Eco-friendly material. Carbon fiber contribute to improving the environmental effect such as fuel saving, expansion of loadage, reducing the exhaustion of carbon dioxide through the weight reduction of transport area. In addition, The carbon fiber is applied to the ship in the area of race yacht, luxury cruise boat as weight reduction and high added-value materials, but there is limited application for general boat because price of carbon fiber is very expensive. For the weight reduction of general boat hull, being used as structure materials, glass fiber and carbon fiber are applied to hull with form of hybrid composite materials, but application of domestic and research for development are incomlete. In this study, An evaluations of mechanical strength property and fatigue strength are performed on composite materials by hybrid weaving of glass fiber and carbon fiber and composite materials forming method by hybrid forming.