• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.197.2-197
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• 2003

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.244-244
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• 2003

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.433-441
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• 2024

This study aims to prevent freezing of existing domestic buildings by developing an energy storage mortar with increased energy efficiency that can reduce the increase in carbon emissions and maintenance costs due to external energy use due to heat wires in civil engineering and buildings with embedded heat wires. I suggest. Research has focused on incorporating phase change materials (PCMs) into common cement composites to provide latent heat performance. However, concrete mixed with phase change materials shows problems such as leakage of phase change materials, decreased strength, and insufficient thermal performance. To overcome this problem, we encapsulate phase change materials using microcapsules and mix them into cement composites to minimize strength loss and leakage, and use multi-walled carbon nanotubes and silica fume to minimize the strength reduction of concrete. A heat storage cement composite was developed. When high-efficiency heat storage cement was used as a replacement for ordinary cement composite in an environment where heat wires were buried, the effect was shown to reduce energy by about 42 %, and compared to a cement composite containing only PCM, the compressive strength and bending strength were 18 % and 23 %, respectively. was improved and its effectiveness was proven.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.412-412
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• 2016

염료감응 태양전지(dye-sensitized solar cells, DSSCs)는 식물의 광합성원리와 매우 유사한 작동원리를 갖고 있는 전지이며, 간단한 구조, 저렴한 제조단가, 친환경성 등의 등의 장점으로 인하여 많은 관심을 모으고 있다. 이러한 염료감응 태양전지는 빛을 받아들인 염료분자가 전자-홀 쌍을 생성하며 전자는 반도체 산화물을 통해 이동되고 전해질의 산화환원 과정을 통해 염료 분자가 다시 환원되는 순환메커니즘을 따르고 있다. 일반적으로 염료감응 태양전지는 밴드 갭 에너지가 큰 반도체 산화물을 포함하는 작업전극, 산화환원 반응을 통해 전자를 염료로 보내는 전해질, 환원 촉매역할을 하는 상대전극으로 구성되어 있다. 특히, 상대전극으로는 우수한 촉매특성과 높은 전도성을 갖는 백금이 가장 많이 이용되고 있지만 가격이 비싸고 요오드에 취약하기 때문에 상용화에 큰 장애물이다. 따라서, 백금을 대체하기 위해 저가의 탄소나 고분자에 대한 연구가 활발히 진행되고 있고, 그 중 탄소나노섬유(carbon nanofiber, CNFs)는 높은 표면적과 뛰어난 화학적 안정성으로 촉매효율을 증대시킬 수 있어 촉매물질로서 관심이 높아지고 있다. 본 연구에서는 상대전극에 탄소나노섬유기반 복합체를 합성하였고, 성공적으로 저가격 및 고성능의 염료감응 태양전지를 제작하였다. 이때, 지지체인 탄소나노섬유는 전기방사법을 통해 합성하였으며, 수열합성법을 이용하여 금속산화물을 담지하였다. 이렇게 제작된 탄소나노섬유-Fe2O3 복합체는 scanning electron microscopy, transmission electron microscopy, X-ray diffraction, 그리고 X-ray photoelectron spectroscopy 통해 구조적, 화학적 특성을 평가하였으며 전기화학적 특성 및 광전변환 효율을 분석하기 위해 cyclic voltammetry, electrochemical impedance spectroscopy, 그리고 solar simulator를 사용하였다. 본 학회에서 위와 관련된 더 자세한 사항에 대해 논의할 것이다.

• Polymer(Korea)
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• v.35 no.6
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• pp.615-618
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• 2011

Carbon nanotubes (CNTs) draw attention as promising materials due to their excellent electrical and mechanical properties. However, the intrinsic strong interaction between CNTs presents a challenge to their use in various applications. Here, we present a facile method to disperse single-walled carbon nanotubes (SWCNTs) in a polar solution using a graft copolymer, poly(vinyl chloride)-graft-poly(oxyethylene methacrylate), PVC-g-POEM. The graft copolymer was synthesized via atom transfer radical polymerization (ATRP), as confirmed by gel permeation chromatography (GPC) and $^1H$ NMR spectroscopy. The SWCNTs were uniformly dispersed in a polar solvent such as dimethylsiloxane (DMSO) using PVC-g-POEM as a dispersant, due to interaction between CNT and the graft copolymer, as revealed by transmission electron microscopy (TEM) analysis. Upon removal of the solvent, free standing nanocomposite films with good homogeneity were obtained.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.58-62
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• 2010

CNT-$TiO_{2}$ nano complexes were prepared from $TiOSO_4$ and multi-walled carbon nanotube (MWCNT) by hydrolysis. The CNTs were dispersed uniformly with anatase $TiO_{2}$ in the prepared $TiO_{2}$-CNT complexes. The increasing MWCNT ratio leads to increased crystalline carbon and O/Ti ratio. The decomposition degree of methylene blue was experienced according to UV radiation time for study adsorption and photocatalytic activity. The samples having high MWCNT ratio show high adsorption and photodegradation. The high specific surface area, functional group having oxygen, low band gap energy, high electric conductivity, high volume to surface ratio, uniform structure and properties of MWCNT assist photocatalytic activity of CNT-$TiO_{2}$ complex.

• Polymer(Korea)
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• v.33 no.2
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• pp.97-103
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• 2009

Ultra-high molecular weight polyethylene (UHMWPE)/functionalized-MWNT hybrid films were prepared by the solution intercalation method, using 4-cumylphenol-MWNT (CP-MWNT) as the functionalized-MWNT. The variation of the thermomechanical properties, morphology, gas permeability, and optical transparency of the hybrid films with CP-MWNT content in the range of 0$\sim$2.00 wt% were examined. The newly synthesized UHMWPE/functionalized-MWNT hybrid films were characterized by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and a universal tensile machine (UTM). It was found that the addition of only a small amount of functionalized-MWNT was sufficient to improve the thermomechanical properties of the UHMWPE hybrid films, with maximum enhancement being observed in the CP-MWNT loading in the range 0.50 to 1.00 wt%. The maximum enhancement in the oxygen gas barrier was also found at the functionalized MWNT content of 1.00 wt%. In this work, the thermomechanical properties and gas permeability of the hybrid films were found to be better than those of pure UHMWPE.

• Korean Journal of Materials Research
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• v.8 no.4
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• pp.312-316
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• 1998

ZnO- TiO$_2$, and Sn0$_2$ - Ti0$_2$ ceramic composites doped with TiO$_2$ were prepared and their electrical and 1000ppm CO gas sensing properties were investigated. The phases of samples were analyzed by XRD, and the microsturctures of the fractured surface of samples were observed by SEM. A carbon monoxide gas sensitivity was de¬fined as the ratio of the resistance in dry air atmosphere(R$drt air$) to the resistance in 1000ppm CO gas atmosphere(R$_co$) The CO gas sensitivity of Smol% Ti0$_2$-added ZnO decreased about 1.7 times compared to that of pure ZnO. On the other hand, the maximum CO gas sensitivity of Ti0$_2$-added SnO$_2$ increased about 2.5 times compared to that of pure SnO$_2$. Therefore, the CO gas sensitivies of SnO$_2$-TiO$_2$ composite were better than those of ZnO- Ti0$_2$ and the temper¬ature range showing the maximum sensitivity for Sn0$_2$-TiO$_2$ composite was lower than that for ZnO- Ti0$_2$.

• Membrane Journal
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• v.29 no.6
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• pp.308-313
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• 2019

In this study, the Fe₃O₄/porous carbon composite was synthesized by hydrothermal method for removal of Cu²⁺ ions and the characteristic of Cu²⁺ ions removal was performed. The Fe₃O₄/porous carbon composite was investigated via using SEM, XRD for its morphology and structure. BET analysis was conducted to conform a specific area and pore size distribution of the composite. For the investigation of the performance for removal of Cu²⁺ ions in the solution, UV-vis spectrometer was used. It suggests that a synergetic effect between magnetic Fe₃O₄ and porous carbon shows an improvement for removal of Cu²⁺ ions.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.411-419
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• 2022

This study conducted acute oral toxicity test and acute dermal toxicity test to evaluate the toxicity of lightweight and high-strength cement composite containing carbon nanotube. It was compared with the toxicity of ordinary concrete that did not contain carbon nanotube. Both lightweight and high-strength cement composite and ordinary concrete were categorized in GHS category 5 as a result of acute oral toxicity test. In addition, no toxic symproms were observed during the acute dermal toxicity test in all specimens, concluding that those were judged to correspond to GHS category 5/unclassified.