• Structural Engineering and Mechanics
• /
• v.76 no.1
• /
• pp.27-56
• /
• 2020

In this paper, the deflection and buckling analyses of porous nano-composite piezoelectric plate reinforced by carbon nanotube (CNT) are studied. The equations of equilibrium using energy method are derived from principle of minimum total potential energy. In the research, the non-local strain gradient theory is employed to consider size dependent effect for porous nanocomposite piezoelectric plate. The effects of material length scale parameter, Eringen's nonlocal parameter, porosity coefficient and aspect ratio on the deflection and critical buckling load are investigated. The results indicate that the effect of porosity coefficient on the increase of the deflection and critical buckling load is greatly higher than the other parameters effect, and size effect including nonlocal parameter and the material length scale parameter have a lower effect on the deflection increase with respect to the porosity coefficient, respectively and vice versa for critical buckling load. Porous nanocomposites are used in various engineering fields such as aerospace, medical industries and water refinery.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.11
• /
• pp.1023-1028
• /
• 2003

The field emission characteristics are studied by simulation for carbon nanotube triode structures with a strip-shaped emitter and a gate hole aligned with it. Two structures, one with double-edge and the other with single edge are analyzed. They show good emission characteristics. Emissions of electrons are concentrated on the edges of emitter and the emitted current increases as the distance between emitter and gate decreases. For single-edged emitter, the emitted electrons form a narow strip-shaped beam which has a good directionality. These triode structures have advantages in that they can be easily fabricated and aligned for assembly.

• Carbon letters
• /
• v.13 no.2
• /
• pp.126-129
• /
• 2012

Nanocomposite films were made by a simple solution casting method in which multi-walled carbon nanotubes (MWCNT) and magnetite nanoparticles ($Fe_3O_4$) were used as dopant materials to enhance the electrical conductivity of chitosan nanocomposite films. The films contained fixed CNT concentrations (5, 8, and 10 wt%) and varying $Fe_3O_4$ content. It was determined that a 1:1 ratio of CNT to $Fe_3O_4$ provided optimal conductivity according to dopant material loading. X-ray diffraction patterns for the nanocomposite films, were determined to investigate their chemical and phase composition, revealed that nanoparticle agglomeration occurred at high $Fe_3O_4$ loadings, which hindered the synergistic effect of the doping materials on the conductivity of the films.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.414-414
• /
• 2012

차세대 플렉시블 디스플레이 소재로서, 탄소나노뷰브(CNT) 기반의 투명전도막은 기존의 ITO 박막보다 우수한 유연성을 갖기 때문에 많은 관심을 모으고 있다. 특히 낮은 저항과 투과도를 유지하면서 투명 전도막의 내구성을 향상시키는 연구는 상업화에 가장 필요한 연구 분야이다. 본 연구에서는 다층벽 탄소나노튜브(MWCNT)를 이용하여 제작된 투명 전도막의 내구성을 개선하기 위하여 오버 코팅을 통한 물성 개선을 연구하였다. 투명전도막은 PET기판 위에 스프레이 방식을 이용하여 균일하게 코팅하였다. 오버 코팅 물질로는 실리콘계 유무기하이브리드 투명하드 코팅을 적용하였다. 연구결과 오버 코팅층과 CNT 코팅층과의 젖음성이 물성 향상에 가장 많은 영향을 끼치는 것을 관찰하였고, 특히 젖음성이 증가할수록 투과도와 전기전도도가 향상되는 것을 확인하였다. 또한 고온 고습 환경에서 240시간 이상 내구성 테스트 결과, 저항률 변화가 1.1 이하인 것을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.923-926
• /
• 2004

Active-matrix field emission display (AMFED) based on carbon nanotube (CNT) emitter and amorphous silicon thin-film transistor (a-Si TFT) is reviewed. The AMFED pixels consisted of a high-voltage a-Si TFT and mesh-gated CNT emitters. The developed AMFED panel showed a high performance with a driving voltage of below 15 V. The low-cost and large-area AMFED approach with a metal mesh technology will be discussed.

• Journal of the Korean Ceramic Society
• /
• v.49 no.2
• /
• pp.155-160
• /
• 2012

This paper reported a simple deposition-precipitation method, introducing the metal (Ni, Ag and Sn) and $Na_2S{\cdot}5H_2O$ to preparedispersion metal sulfide nanoparticles on the surface of the Multi-walled carbon nanotube for synthesis of CNT-$M_xS_y$ ($NiS_2$, $Ag_2S$, SnS) composite photocatalysts. The characterization of the prepared CNT-$M_xS_y$ ($NiS_2$, $Ag_2S$, SnS) composites was performed by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis and BET analysis. Furthermore, the MB degradation rate constant for CNT-SnS composite was $5.68{\times}10^{-3}$ under visible light irradiation, which was much higher than the corresponding values for other samples. The detailed formation and photocatalytic mechanism are also provided here.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.300-305
• /
• 2004

A preliminary study on. field emitter array cathodes was conducted aiming at applying for electrodymanic tether (EDT) propulsion systems. The EDT propulsion systems are assumed to use for active removal systems of post-mission spacecraft, which would otherwise become space debris. A survey on field emit-ter array cathode technology was conducted, and it showed that carbon nanotube (CNT) emitters are suit-able to EDT application. Trial fabrications and evaluation tests of CNT emitters were conducted, which demonstrated a target emission current density of 10 ㎃/$\textrm{cm}^2$. It was found out that the most important technical issue for developing CNT emitters is to improve the performance against voltage breakdown between the emitter and the opposite electrode.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.2
• /
• pp.163-167
• /
• 2006

This paper shows a gigahertz actuator based on multi-wall carbon nanotubes(CNT) encapsulating metallic ions using classical molecular dynamics simulations. Encapsulated potassium ions accelerated by an applying external electric field could initialize a gigahertz actuator composed of a $7K^{+}(a)CNT$ oscillator.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.6
• /
• pp.182-188
• /
• 2018

Recently, various researches on the utilization of carbon nanotube(CNT) with superior electrical conductivity and large surface areas into concrete have been actively conducted. Thus, mechanical and thermal properties of cement-flyash composites were evaluated concerning the CNT replacements. Based on the low binder-to-water ratio, the cement composites were produced with 0.2 % and 0.5 % of CNT solids. The compressive strengths with various ages, isothermal calorimetry measurement, SEM analysis, thermal conductivity of cement composites and thermal gravimetry analysis were implemented. As the amount of CNT addition was increased, the thermal conductivity of cement composites were also increased. Also, there was no significant mechanical property differences between mixtures with and without CNTs.

• Korean Journal of Materials Research
• /
• v.15 no.11
• /
• pp.711-716
• /
• 2005

The effects of change in the component of bonding materials in carbon nanotube cathode (CNT-cathode) on field enhancement and field emission characteristics were investigated. The field enhancement factor$\beta$ was dependent on the electrical conductivity of the bonding materials. The use of frit glass as a bonding material showed a higher field enhancement factor and better field emission characteristics than an Ag paste. The reason for why the frit glass showed better field emission characteristics can be summarized as follows. First, a frit glass improves the real aspect ratio of CNTs compared to an Ag paste. Second, the number of CNTs in CNT-cathodes is considerably reduced because the CNTs were extensively oxidized during $390^{\circ}C$ heat treatment in air atmosphere in the case of Ag paste.