• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.3
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• pp.143-150
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• 2007

Six full scale column specimens have been tested under the constant axial and cyclic lateral load. An equivalent stress block parameter was used to estimate flexural capacity of columns confined by carbon sheet tube. Through the non-linear regression analysis, behaviors of CFCST(Concrete Filled Carbon Sheet Tube) columns under the cyclic lateral load were estimated and compared with test results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.152-159
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• 2006

An experimental research has been performed to investigate capacity of CFCST(Concrete Filled Carbon Sheet Tube) columns because column member is one of the most important structural members. Generally, two shapes of column sections, rectangular and circular shapes, are designed but the circular shape which has constant curvature was chosen for this study. Total 17 column specimens confined by carbon sheet tube were tested using 10,000kN universal test machine(UTM).

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.106-112
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• 2016

In this study, circular concrete column specimens confined by carbon sheet tube with different winding angles and different number of carbon sheet plies(3T, 5T and 7T) were tested to propose design equations and a strength reduction factor. Specimens were designed by 300 mm diameter and 600 mm height with $90^{\circ}{\pm}0^{\circ}$, $90^{\circ}{\pm}30^{\circ}$, $90^{\circ}{\pm}45^{\circ}$, $90^{\circ}{\pm}60^{\circ}$, $90^{\circ}{\pm}75^{\circ}$ and $90^{\circ}{\pm}90^{\circ}$ carbon fiber angles. A 10,000 kN UTM was used for compressive strength test of specimens by displacement control method with 0.01 mm/sec velocity. Estimation equations of compressive strength and ultimate strain of circular concrete column specimens confined by carbon sheet tube using a regression analysis and a strength reduction factor to apply ultimate strength design method of concrete were proposed. The strength reduction factor(${\phi}$) of circular concrete columns confined by carbon sheet tube was estimated as 0.64 by the Monte Carlo Analysis Method. Manufacture and construction process have to be perfectly managed by construction managers because the structural capacities of carbon tubes were depends on construction abilities of manufacturing operators.

• Composites Research
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• v.33 no.6
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• pp.395-400
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• 2020

In this paper, we manufactured silsesquiaznae (SSQZ)-coated carbon nanotube (CNT) surface heating elements, which allowed stable heating at high temperatures. The prepared composite sheet was confirmed by FE-SEM that the SSQZ fully coated the surface of CNT sheet. Furthermore, it was also confirmed that the silicon carbonitride (SiCN) ceramic formed by heat treatment of 800℃ have no defects found and maintain intact structure. The CNT/SiCN composite sheet was able to achieve higher thermal stability than raw CNT sheets in both nitrogen and air atmosphere. Finally, the CNT/SiCN composite sheet was possible to heat up at a temperature of over 700℃ in the atmosphere, and the re-heating was successfully operated after cooling.

• Elastomers and Composites
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• v.46 no.3
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• pp.231-236
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• 2011

The polyacrylate/multi-walled carbon nanotube (MWNT) composites were prepared and investigated for the application as a counter electrode in solar cell. The electrical conductivity of the composites was increased with increasing MWNT content and with the thickness of the sheet. The surface resistivity value of the composite at 50 wt% loading of MWNT was 0.36 ${\Omega}$/sq. The thermal decomposition temperature of the composites was also increased with the MWNT contents, and the increase of $15^{\circ}C$ was observed at the composite of polyacrylate/MWNT (50/50, w/w). The increase of storage modulus of the composites was observed, especially at the higher temperature compared to polyacrylate. The dimensional change of polyacrylate decreased over $20^{\circ}C$, but that of the composite increased linearly with the temperature. The morphology of the composites stands for the good dispersion of MWNT into the polyacrylate matrix.

• KIEAE Journal
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• v.7 no.6
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• pp.119-126
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• 2007

In the field of composite structures, the use of carbon tube for the confinement of concrete has been arisen since 1990's. However, experimental and analytical studies were limited to those of reinforced concrete and concrete filled steel tube. The carbon tube provides excellent confinement capabilities for concrete cores, enhancing compressive strength and ductility of concrete significantly. The carbon tube has high tensile strength, light weight, corrosion immunity and high fatigue strength properties. Since carbon fiber is an anisotropic material, carbon tube could be optimized by adjusting the fiber orientation, thickness and the number of different layers. In this study, both experimental and analytical studies of axial and lateral behavior of full-scale CFCT (Concrete Filled Carbon Tube) columns subjected to monotonic axial load were carried out using Drucker-Prager theory. And, based on comparison results between experiment results and analytical results, k factor estimation was proposed for effective analysis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.199-204
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• 2003

The purpose of this study is to experimentally investigate the structural performance of concrete exterior beam-column joints confined by carbon sheet tube. Four specimens were produced with different numbers of carbon sheet and the other specimen was produced with reinforced concrete. A hydraulic dynamic actuator with 30tonf capacity was used to cyclic lateral loading test. The experimental results represent that the numbers of carbon sheet have an influence the load and displacement capacity. However, the bond length of carbon sheets for connecting beam and column has to be considered to improve the capacity of joint.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.58-58
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• 2011

CNT 나노기술을 응용한 IT산업용 적층간지용 ESD(정전방전, Electrostatic Dissipation)PU 발포필름의 제조 가공기술 및 상품화 개발은 전자제품 패키지에 요구되는 쿠션성과 정전방전 기능을 갖는 폴리우레탄 발포 필름의 제조기술을 확립함으로써 가능 할 수 있다. 특히 IT산업용 필름제품이 개발되면 ESD 성능을 발휘하게 됨으로서 정전기 쇼크에 의한 각종 전자제품의 오작동이나 파손 방지가 가능하게 되어 포장재, 자동차, 전자제품의 하우징 등으로 사용될 수 있게 된다. 현재까지 ESD 기능을 부여하기 위해서 사용되는 충전재로는 금속섬유, 금속플레이크, 탄소섬유, 카본블랙 등이 있으며, 최근 탄소나노튜브를 응용한 연구가 많이 진행되고 있는데 탄소나노튜브는 직경이 수십nm, 종횡비 1000이상의 나노섬유형태로 서 전기전도성이 구리수준으로 알려져 있고 소량을 충전할 시 기계적 특성도 오히려 증대하는 장점을 가지고 있으며 전기적 특성으로는 상대적으로 낮은 나노튜브 함량에서는 ESD를 들 수 있고 높은 함량에서는 전자파 차폐성까지 기대되고 있다. 본 연구에서는 우수한 인장강도, 기계적 강도, 열적 안정성, 내약품성을 가지면서 습식 또는 용융공정을 통해 용이하게 시트, 필름, 코팅제를 제조할 수 있는 방수, 투습방수성을 가지는 유연재료인 폴리우레탄(PU) 1액형 PU에 MWNT 함량이 3wt%인 IPA/MWNT 분산용액을 PU 함량 대비 20, 30, 40파트로 함유시켜 $120^{\circ}C$에서 2분 건조시켜 제조한 그라운드 필름에 2액형 PU와 IPA/MWNT 분산용액에 발포제를 첨가하여 발포온도 140, 150, $160^{\circ}C$에서 5분간 건조시켜 시료 필름을 제조하였다. 제조된 필름의 전기전도성 측정은 부피저항과, 표면저항을 각각 측정하여 확인하였으며, 필름의 마찰 대전압은 E.S.T-7 마찰 대전압 시험기를 이용하여 표면 마찰 대전압과 반감기를 측정하여 확인하고, 필름의 물리적 특성은 인장시험기를 이용하여 breaking stress, breaking strain을 구하였다. 필름의 표면 특성은 영상 현미경 시스템을 사용하여 ${\times}1000$ 배율로 측정하여 분산특성과의 연관성을 확인하였다.