• Title/Summary/Keyword: Carbon nano tube

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Nitrogen Effect on Vertically Aligned CNT Growth (수직배향 CNT의 성장에 미치는 질소의 영향)

  • 김태영;오규환;정민재;이승철;이광렬
    • Journal of the Korean Vacuum Society
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    • v.12 no.1
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    • pp.70-77
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    • 2003
  • It is well Down that the growth of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) using a transition metal catalyst is greatly enhanced in a nitrogen environment. We show here that the enhanced growth is closely related to the activated nitrogen and it's incorporation into the CNT wall and cap during growth. This behavior is consistent with theoretical calculations of CNx thin films, showing that nitrogen incorporation to the graphitic basal plane reduces the elastic strain energy for curving the graphitic layer. Enhanced CNT growth by nitrogen incorporation is thus due to a decrease in the activation energies required for nucleation and growth of the tubular graphitic layer.

Fabrication of AZ31/CNT Surface Composite by Friction Stir Processing (마찰교반공정에 의한 AZ31/CNT 표면 복합재료 제조)

  • Kim, Jae-Yeon;Lee, Seung-Mi;Hwang, Jung-Woo;Byeon, Jai-Won
    • Journal of the Korean Society for Heat Treatment
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    • v.28 no.6
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    • pp.315-321
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    • 2015
  • Friction stir processing (FSP) was applied to fabricate AZ31/CNT (Carbon Nano Tube) surface composite for improvement of surface hardness of AZ31 Mg-based alloy. The effects of traverse speed of rotating tool and volume fraction of CNT (i.e., groove depth of 3 mm and 4 mm) on the soundness and hardness of the composite layer were investigated. Multi-walled CNTs were fully filled in a machined groove and stirring tool was rotated at the speed of 1400 rpm. Only under the tool traverse speed of 25 mm/min for the specimen with a groove depth of 3 mm, surface composite layer with no defect was successfully produced. Increased hardness of about 35% was observed in the composite layer.

Theoretical impact of Kelvin's theory for vibration of double walled carbon nanotubes

  • Hussain, Muzamal;Naeem, Muhammad N.;Asghar, Sehar;Tounsi, Abdelouahed
    • Advances in nano research
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    • v.8 no.4
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    • pp.307-322
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    • 2020
  • In this article, free vibration of double-walled carbon nanotubes (DWNT) based on nonlocal Kelvin's model have been investigated. For this purpose, a nonlocal Kelvin's model is established to observe the small scale effect. The wave propagation is employed to frame the governing equations as eigenvalue system. The influence of nonlocal parameter subjected to different end supports has been overtly examined. The new set of inner and outer tubes radii investigated in detail against aspect ratio. The influence of boundary conditions via nonlocal parameter is shown graphically. Due to small scale effect fundamental frequency ratio decreases as length to diameter ratio increases. Small scale effect becomes negligible on all end supports for the higher values of aspect ratio. With the smaller inner tube radius double-walled CNT behaves more sensitive towards nonlocal parameter. The results generated furnish the evidence regarding applicability of nonlocal model and also verified by earlier published literature.

Materials Characterization and the Microstructure of Pure Cu and Cu-3vol%CNT Composite Fabricated From Optimization of SPS Processing Variables (SPS 공정 변수의 최적화에 의한 Pure Cu와 Cu-3vol%CNT composite의 미세구조와 소재특성)

  • Lee, Hee Chang;Kim, Hye Sung
    • Journal of the Korean Society for Heat Treatment
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    • v.33 no.4
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    • pp.185-192
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    • 2020
  • In this study, materials characterization of pure copper and copper based carbon nano-tube composite prepared by powder metallurgy method were investigated. Prior to evaluate materials characterization, spark plasma sintering processing variables such as sintering temperature, pressure, thickness and diameter of compacts was optimized to ensure the microstructure and materials property of pure Cu and Cu-CNT composite. In addition, corrosion behavior of Cu-based CNT composite produced by powder sintering method was investigated. It was confirmed from this study that the corroded surfaces of the composite shows less dissolution compared with pure copper in 3.5 wt% NaCl solution. The measured corrosion current density (Icorr) indicates improved corrosion property of Cu based composite containing small additions of CNTs in chloride containing media. Micro-galvanic activity between Cu and CNT was not observed in given sintering condition.

Circuit Components Based on New Materials: The Reality of Multitechnology System on Systems Hyperintegration

  • Eshraghian, Kamran;Cho, Kyoung-Rok
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.3
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    • pp.106-111
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    • 2010
  • The convergence of significantly different and disparate technologies such as spintronics, carbon nano tube field effect transistors, photon and bio-responsive molecular switches, memristor and memristive systems and metamaterials, coupled with energy scavenging sources are gaining a renewed focus in the quest for new products. This paper will provide an insight into an anticipated technological revolution and will highlight a futuristic Roadmap to capture opportunities that are brought about as the results of formulation of new circuit components basically driven by emergence of nanoscale materials as part of System on System integration. Challenges as the result of new lumped components such as memristor, metamaterial-based lumped components and the like that will challenge the designers' comfort zone will also be discussed.

Principle Measurement for Sheet Resistance of Large Size Conductive Thin Films (대면적 전도성 박막의 면저항 정밀측정)

  • Kang, Jeon Hong;Yu, Kwang Min;Lee, Sang Hwa
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.1515-1516
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    • 2015
  • Touch panel 및 Touch screen 등의 투명전극으로 많이 사용되고 있는 ITO(Indium Tin Oxide)나 CNT(Carbon Nano Tube) 등 전도성 박막의 면저항을 쉽고 빠르게 측정하기 위하여 van der Pauw method를 이용한 면저항 측정기를 개발하였다. 이 면저항 측정기는 대면적 시료의 면저항을 측정 할 수 있어 매우 편리하다. 면저항 측정은 주로 Four Point Probe method로 측정하는 것이 일반적이나 본 연구에서는 van der Pauw method를 이용한 측정값과 Four Point Probe method로 측정한 결과를 비교한 결과 1 % 이내에서 일치하였다. 개발된 측정기의 측정 정확도는 지시값의 1.0 % 이하이고, 측정범위는 $2{\Omega}/{\square}{\sim} 5k{\Omega}/{\square}$이다.

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Durability of the Flexible Shape Memory Device (형상 기억 유연 소자의 내구성 평가에 관한 연구)

  • Yang, Hee-Kyung;Kim, Hae-Jin;Kim, Dae-Eun
    • Transactions of the Society of Information Storage Systems
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    • v.11 no.2
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    • pp.36-40
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    • 2015
  • The demand for flexible devices including solar cells, memories and batteries has increased rapidly over the past decades. In most flexible devices, polymer-based materials are used to enable the mechanical deformations such as bending or folding. Shape Memory Polymers (SMPs) is a high molecular compound polymer with flexibility and shape recovery characteristics. In this work, flexible shape memory device was fabricated by simply coating the conducting material, carbon nano-tube (CNT), on a shape memory polymer. Furthermore, durability of the device under various type of mechanical deformations was assessed. It is believed that the result of this work will aid in realization of a stretchable and wearable electronic device for practical applications.

Fundamental properties of repair mortar using CNT impregnated in porous material (다공성 소재에 함침된 CNT를 이용한 보수모르타르의 기초적 특성)

  • Kim, Young Min;Kwon, Hyun Woo;Lee, Gun Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.67-68
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    • 2021
  • In this study, Repair mortar was prepared using CNT powder with improved dispersibility and its characteristics were analyzed. As a result of the experiment, the compressive strength and flexural strength were found to be at similar levels compared to Plain without CNT. In addition, as a result of the drying shrinkage test, it was found that the drying shrinkage amount was decreased due to the effect of CNT mixed into the porous material filling the internal pores of the repair mortar.. The Bond strength of the repair mortar was at a similar level regardless of whether CNT was added or not

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Synthesis and Electrochemical Characteristics of Carbon added Li3V2(PO4)3 (탄소첨가한 Li3V2(PO4)3의 합성 및 전기화학적 특성)

  • Jo, Yeong-Im;Na, Byung-Ki
    • Journal of the Korean Electrochemical Society
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    • v.15 no.2
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    • pp.101-108
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    • 2012
  • The purpose of this study was to improve the conductivity of $Li_3V_2(PO_4){_3}$ by adding carbon source so that the discharge rate and cyclic properties were improved. Glucose and CNT were added to $Li_3V_2(PO_4){_3}$ and the structure and electrochemical properties were studied. $Li_3V_2(PO_4){_3}$, $Li_3V_2(PO_4){_3}$/C and $Li_3V_2(PO_4){_3}$/CNT were synthesised by solid state reaction using hydrogen reduction method at 600, 700, 800, $900^{\circ}C$. The cathode materials were assembled to coin cell type 2032 with Lithium metal as a counter electrode. The coin cell was galvanostatically evaluated in the voltage range of 3.0~4.8 V.

Detection Characteristics for the Ultra Lean NOx Gas Concentration Using the MWCNT Gas Sensor Structured with MOS-FET (MOS-FET 구조의 MWCNT 가스센서를 이용한 초희박 NOx 가스 검출 특성)

  • Kim, Hyun-Soo;Lee, Seung-Hun;Jang, Kyung-Uk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.9
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    • pp.707-711
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    • 2013
  • Carbon nanotubes(CNT) has strength and chemical stability, greatly conductivity characteristics. In particular, MWCNT (multi-walled carbon nanotubes) show rapidly resistance sensitive for changes in the ambient gas, and therefore they are ideal materials to gas sensor. So, we fabricated NOx gas sensors structured MOS-FET using MWCNT (multi-walled carbon nanotubes) material. We investigate the change resistance of NOx gas sensors based on MOS-FET with ultra lean NOx gas concentrations absorption. And NOx gas sensors show sensitivity on the change of gate-source voltage ($V_{gs}=0[V]$ or $V_{gs}=3.5[V]$). The gas sensors show the increase of sensitivity with increasing the temperature (largest value at $40^{\circ}C$). On the other hand, the sensitivity of sensors decreased with increasing of NOx gas concentration. In addition, We obtained the adsorption energy($U_a$), $U_a$ = 0.06714[eV] at the NOx gas concentration of 8[ppm], $U_a$ = 0.06769[eV] at 16[ppm], $U_a$ = 0.06847[eV] at 24[ppm] and $U_a$ = 0.06842[eV] at 32[ppm], of NOx gas molecules concentration on the MWCNT gas sensors surface with using the Arrhenius plots. As a result, the saturation phenomena is occurred by NOx gas injection of concentration for 32[ppm].