• 전기전자학회논문지
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• 제27권3호
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• pp.327-332
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• 2023

전통적인 실리콘 기반 반도체 소자 보다 높은 성능과 다양한 활용성으로 차세대 반도체 후보로 높은 관심 받고 있는 CNTFET은 CNT 배치와 같은 CNTFET만의 고유한 공정 편차가 아직 성숙되지 않아 상용화에 어려움을 겪고 있다. 이러한 어려움을 극복하고자 반복적인 회로 구성으로 공정 편차의 영향을 적게 받는 회로를 MOSFET-CNTFET 기반 하이브리드 회로로 구현하여 CNTFET 의 장점을 취하고 단점을 보완하고자 하는 수많은 연구들이 지속적으로 수행되어 왔다. 본 논문에서는 하이브리드 SRAM의 성능이 기존의 MOSFET SRAM 또는 CNTFET SRAM에 존재하는 반도체 공정 변화에 의해 얼마나 변화될 수 있는지를 비교하였다. 시뮬레이션 결과, CNT 밀도를 32nm 당 7개에서 9개 사이로 유지할 수 있다면, hybrid SRAM은 기존 MOSFET SRAM보다 읽기 동작에서 그리고 쓰기 동작에서 공정 편차에 대한 강건성이 각각 약 2.6배 그리고 약 1.1배 있음을 보여준다.

• Steel and Composite Structures
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• 제48권3호
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• pp.275-291
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• 2023

This paper has focused on presenting vibration analysis of trapezoidal sandwich plates with 3D-graphene foam reinforced polymer matrix composites (GrF-PMC) core and FG wavy CNT-reinforced face sheets. The porous graphene foam possessing 3D scaffold structures has been introduced into polymers for enhancing the overall stiffness of the composite structure. Also, 3D graphene foams can distribute uniformly or non-uniformly in the plate thickness direction. The effective Young's modulus, mass density and Poisson's ratio are predicted by the rule of mixture. In this study, the classical theory concerning the mechanical efficiency of a matrix embedding finite length fibers has been modified by introducing the tube-to-tube random contact, which explicitly accounts for the progressive reduction of the tubes' effective aspect ratio as the filler content increases. The First-order shear deformation theory of plate is utilized to establish governing partial differential equations and boundary conditions for trapezoidal plate. The governing equations together with related boundary conditions are discretized using a mapping-generalized differential quadrature (GDQ) method in spatial domain. Then natural frequencies of the trapezoidal sandwich plates are obtained using GDQ method. Validity of the current study is evaluated by comparing its numerical results with those available in the literature. It is explicated that 3D-GrF skeleton type and weight fraction, carbon nanotubes (CNTs) waviness and CNT aspect ratio can significantly affect the vibrational behavior of the sandwich structure. The plate's normalized natural frequency decreased and the straight carbon nanotube (w=0) reached the highest frequency by increasing the values of the waviness index (w).

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.69-70
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• 2003

10 wt.% of PAN was dissolved in N,N-dimethylformamide (DMF) and 1 wt. % of the multi wall carbon nanotubes (MWCNTs) was evenly dispersed in PAN solution by using ultrasonic miner. The 1 wt.% addition of MWCNT increased the specific capacitance by two times more from 82 to 160 F/g. The specific capacitance of carbon nanofiber(CNF)/carbon nanotube(CNT) composite capacitors was about 90 F/g at the current density of 500 mA/g. This value is even larger than the capacitance from the CNF electrode at the current density of 5 mA. The relatively high capacitance at the high current density is a practical importance for applications to supercapacitor in motor vehicle.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1096-1099
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• 2005

Multi-walled carbon nanotubes (CNTs) grown on catalyst dots by thermal chemical vapor deposition were vertically aligned with a high population density. Such densely populated CNTs showed poor field emission characteristics due to the electrical screening effect. We reduced the number density of CNTs using an adhesive tape treatment. For dotpatterned CNTs, the tape treatment decreased the CNT density by three orders of magnitude, drastically improved the turn-on electric field from 4.8 to $1.8V/{\mu}m$, and changed the emission image from spotty to uniform luminescence. We also report long-term emission stability of dot-patterned CNTs by measuring the emission currents with time at different duty ratios.

• 반도체디스플레이기술학회지
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• 제11권2호
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• pp.81-84
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• 2012

Cantilevered carbon-nanotube-resonator was investigated via classical molecular dynamics simulations. The resonator system is including the attached nanocluster. A nanocluster with a finite length was modeling by some atomic rings. The mass of the nanocluster was equally distributed on the carbon atoms, composed of the atomic rings. The effective density factor, which could be considered as the single parameter affecting the resonance frequency shift, was significantly influenced by the mass, the position, and the linear density of the attached nanocluster. The linear density of the attached nanocluster was an important parameter to analyze the vibrational behavior of the CNT-resonator, including the attached nanocluster.

• Carbon letters
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• 제14권1호
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• pp.1-13
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• 2013

Carbon nanotubes (CNTs) are increasingly attracting scientific and industrial interest because of their outstanding characteristics, such as a high Young's modulus and tensile strength, low density, and excellent electrical and thermal properties. The incorporation of CNTs into polymer matrices greatly improves the electrical, thermal, and mechanical properties of the materials. Surface modification of CNTs can improve their processibility and dispersion within the composites. This paper aims to review the surface modification of CNTs, processing technologies, and mechanical and electrical properties of CNT-based epoxy composites.

• 대한기계학회논문집B
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• 제39권6호
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• pp.541-548
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• 2015

본 논문에서는 순차적 화학기상증착법에 기반하여 다양한 구조적 특성을 갖는 산화아연 나노구조체를 탄소나노튜브 상에 3 차원 혼성구조로 형성하는 공정을 개발하고 그 형성 메커니즘을 논한다. 이어서 나노와이어, 나노로드, 나노플레이트, 다결정 나노박막 등 다양한 형상의 산화아연 나노구조를 온도, 압력, 개스유량 등 주요 파라미터들의 조절을 통해 형성할 수 있음을 보이며, 이의 형성 원리에 대해 기본적인 형성 메커니즘과 연계하여 고찰한다. 본 연구 결과를 통해, 압전 및 광전 에너지변환 특성 등 풍부한 기능성을 보유하되 다소 높은 전기저항을 갖는 산화아연 나노구조체를 다양한 포맷으로 양전도성의 탄소나노튜브와 혼성화 함으로써, 각각의 포맷 별로 특화된 보다 폭넓은 응용 분야로의 활용을 구현해 나갈 수 있을 것이다.

• Transactions on Electrical and Electronic Materials
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• 제10권6호
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• pp.217-221
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• 2009

The use of the carbon nanotube (CNT) is superior to the general powder state materials in their thermal and chemical properties. Because its ratio of diameter to length (aspect ratio) is very large, it is known to be a type of ideal nano-reinforcement material. Based on this advantage, the existing carbon black of the semiconductive shield materials used in power cables can acquire excellent properties by the use of a small amount of CNTs. Therefore, we fabricated specimens using a solution mixing method. We investigated the thermal properties of the CNT, such as its storage modulus, loss modulus, and its tan delta using a dynamic mechanical analysis 2980. We found that a high thermal resistance level is demonstrated by using a small amount of CNTs. We also investigated the chemical properties of the CNT, such as the oxidation reaction by using Fourier transform infrared spectroscopy (FT-IR) made by Travel IR. In the case of the FT-IR tests, we searched for some degree of oxidation by detecting the carboxyl group (C=O). The results confirm a tendency for a high cross-linking density in a new network in which the CNTs situated between the carbon black constituent molecules show a bond using similar constructive properties.

• 한국운동역학회지
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• 제22권4호
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• pp.429-435
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• 2012

The purpose of this study was to determine the biomechanical effect of wearing carbon nanotube-based insole on cushioning and muscle tuning during drop landing. Twenty male university students(age: $21.2{\pm}1.5yrs$, height: $175.4{\pm}4.7cm$, weight: $70.2{\pm}5.8kg$) who have no musculoskeletal disorder were recruited as the subjects. Average axial strain, average shear strain, inversion angle, linear velocity, angular velocity, vertical GRF and loading rate were determined for each trial. For each dependent variable, a one-way analysis of variance(ANOVA) with repeated measures was performed to test if significant difference existed among different three conditions(p<.05). The results showed that Average axial strain of line 4 was significantly less in CNT compared with EVA and PU during IP phase. The average shear strain was less in CNT compared with EVA and PU during other phases. The inversion angle was increased in CNT compared with EVA and PU during all phase. In linear velocity, angular velocity, vertical GRF and loading rate, there were no significant difference between the three groups. This result seems that fine particle of carbon nanotube couldn't make geometric form which can absolve impact force by increasing density through eliminating voids of forms. Thus, searching for methods that keep voids of forms may play a pivotal role in developing of insole. This has led to suggestions of the need for further biomechanical analysis to these factors.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.468-470
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• 2004

CNT pastes with different inorganic binder such as glass frit and spin on glass (SOG) were synthesized by using multi-walled nanotube (MWNT) grown by CVD. The uniformity of cathode layer after firing was enhanced and the emission current density at an applied field of 7.95V/${\mu}m$ increased from 133${\mu}A$/$cm^2$ to 265${\mu}A$/$cm^2$ when inorganic binder changed from glass frit to SOG. The emission properties of CNT pastes with SOG were stable and uniform although firing was carried out at relatively high temperature of 450$^{\circ}C$ under air. It is concluded that SOG is more suitable inorganic binder than glass frit for field emission application.