• Title/Summary/Keyword: nanorod

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The growth of ZnO nanorods by hydrothermal method on organic substrates (유기 기판 위에 수열 합성법으로 성장된 ZnO 나노 막대의 특성 연구)

  • Kim, Ah-Ra;Lee, Ji-Yeon;Lee, Ju-Young;Kim, Hong-Seung;Park, Hyun-Kook
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.281-281
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    • 2010
  • In this study, ZnO nanorod arrays are grown on organic substrates by hydrothermal method which requires a low temperature, simple process, and no vacuum. The structure properties of ZnO nanorods were examined by field emission scanning electron microscopy and X-ray diffraction. To detect the optical transmission, ultraviolet visible spectrophotometer was also used. From results, the ZnO nanorods were grown the horizontal growth on the organic substrates had the length of over $10\;{\mu}m$. After deposition of ZnO seed layer, the ZnO nanorod arrays had uniformity orientation and length.

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Modal analysis of viscoelastic nanorods under an axially harmonic load

  • Akbas, Seref D.
    • Advances in nano research
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    • v.8 no.4
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    • pp.277-282
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    • 2020
  • Axially damped forced vibration responses of viscoelastic nanorods are investigated within the frame of the modal analysis. The nonlocal elasticity theory is used in the constitutive relation of the nanorod with the Kelvin-Voigt viscoelastic model. In the forced vibration problem, a cantilever nanorod subjected to a harmonic load at the free end of the nanorod is considered in the numerical examples. By using the modal technique, the modal expressions of the viscoelastic nanorods are presented and solved exactly in the nonlocal elasticity theory. In the numerical results, the effects of the nonlocal parameter, damping coefficient, geometry and dynamic load parameters on the dynamic responses of the viscoelastic nanobem are presented and discussed. In addition, the difference between the nonlocal theory and classical theory is investigated for the damped forced vibration problem.

Zinc oxide seed layer 형성 조건 제어를 통한 나노 구조체 형상 조절 연구

  • Lee, Jae-Hyeok;Kim, Seong-Hyeon;Lee, Gyeong-Il;Lee, Cheol-Seung;Jo, Jin-U;Kim, Seon-Min
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.386-386
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    • 2011
  • sol-gel 및 hydrothermal growth method를 이용한 zinc oxide nanorod는 제작 시 고가의 장비가 필요치 않기에 저비용 대면적 박막을 제작하는데 적합하지만 rod들의 array 및 density 조절에서 어려움을 가지고 있다. 본 연구에서는 이러한 nanorod array 형상 조절을 위하여 zinc oxide seed layer 형성 과정 중 precursor solution에 이종 나노 입자를 첨가하였다. 첨가한 seed precursor solution을 spin coating한 이후에 후처리 하여 hydrothermal method를 이용해 성장시켰다. 합성한 rod들을 optic과 FE-SEM으로 측정해 rod들의 density 변화를 확인할 수 있었다.

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Nucleation Dependence in GaN Nanorod Growth by Metalorganic Chemical Vapor Deposition

  • Bae, Si-Yeong;Lee, Jun-Yeop;Min, Jeong-Hong;Lee, Dong-Seon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.349-349
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    • 2013
  • 질화물 기반 물질은 발광다이오드의 효율 향상과 함께 널리 연구되는 물질의 하나이다. 그러나, 고유의 물성적 특성으로 인한 압전전기장 효과는 넓은 가시광영역에서 궁극적 효율 달성을 위한 장애가 되고 있다. 이를 극복하기 위한 방법 중 하나는 나노 구조이며, 특히 비극성면을 통한 나노구조의 구현은 압전전기장 효과를 제거할 수 있는 장점이 있다. 그러나, 현재까지 이를 위한 질화물 나노로드의 구현은 보통의 경우 발생하는 반극성면의 발현으로 인해 기술적 어려움이 많았다. 이를 위해 제시되는 방법 중 하나인 반복적 성장 기법을 통한 본 그룹의 성공적 나노로드의 구현과 함께, nucleation 조건의 변화에 따른 성장 과정을 분석하여 미래의 고효율 3차원 나노구조 발광 소자를 위한 단서를 제공하고자 한다. Fig. 1은 수소(a)와 질소(b)를 850도부터 1,050도까지 성장 온도를 달리하여 성장했을 때의 모양 변화를 나타내며 이를 통한 GaN nanorod 성장 영향에 대하여 논하고자 한다.

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Fabrication of H2 Gas Sensor Based on ZnO Nanarod Arrays by a Sonochemical Method

  • Lee, Mi-Sun;Oh, Eu-Gene;Jeong, Soo-Hwan
    • Bulletin of the Korean Chemical Society
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    • v.32 no.10
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    • pp.3735-3737
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    • 2011
  • We report a simple method for fabricating ZnO gas sensors via a sonochemical route and their $H_2$ gas sensing properties. Vertically aligned ZnO nanorod arrays as a sensing material were synthesized on a Pt-electrode patterned alumina substrate under ambient conditions. The advantage of the proposed method is a high speed of processing. The gas sensor based on ZnO nanorod arrays with large specific surface area showed a high response to $H_2$ and a detection limit of 70 ppm at $250^{\circ}C$. Also, their response and recovery time were relatively short and a complete regeneration was observed. A mechanism for sensing $H_2$ gas on the surface of ZnO nanorods is proposed.

Thermal evaporation에 의해 성장된 ZnO nanorod의 합성 온도에 따른 특성 평가

  • An, Cheol-Hyeon;Han, Won-Seok;Gang, Si-U;Kim, Yeong-Lee;Choe, Mi-Gyeong;Gong, Bo-Hyeon;Kim, Dong-Chan;Jo, Hyeong-Gyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.62-62
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    • 2007
  • ZnO 박막이 성장된 Si기판을 이용하여 Thermal evaporation을 사용하여 온도에 따라 합성된 1-D의 구조의 ZnO nanorods의 형상과 특성에 대하여 연구를 하였다. 합성온도는 $700^{\circ}C{\sim}900^{\circ}C$를 사용하였고 온도가 낮아짐에 따라 Vertical한 1-D ZnO가 합성이 되는 것을 알 수 있었다. 특히, $700^{\circ}C$에서 합성된 1-D ZnO는 ~100nm의 폭을 가지고 800nm의 길이의 Nanorods로 성장이 되는 것을 알 수 있었고, 상온 PL측정을 통해 온도가 증가함에 따라 O 결핍 또는 Zn의 과잉에 의한 Deep level emission이 증가하는 것을 알 수 있었다.

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Structural properties of β-Fe2O3 nanorods under compression and torsion: Molecular dynamics simulations

  • Kilic, Mehmet Emin;Alaei, Sholeh
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1352-1358
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    • 2018
  • In recent years, one-dimensional (1D) magnetic nanostructures, such as magnetic nanorods and chains of magnetic nanoparticles have received great attentions due to the breadth of applications. Especially, magnetic nanorods has been opened an area of active research and applications in medicine, sensors, optofluidics, magnetic swimming, and microrheology since they possess the unique magnetic and geometric features. This study focuses on the molecular dynamics (MD) simulations of an infinitely long crystal ${\beta}-Fe_2O_3$ nanorod. To elucidate the structural properties and dynamics behavior of ${\beta}-Fe_2O_3$ nanorods, MD simulation is a powerful technique. The structural properties such as equation of state and radial distribution function of bulk ${\beta}-Fe_2O_3$ are performed by lattice dynamics (LD) simulations. In this work, we consider three main mechanisms affecting on deformation characteristics of a ${\beta}-Fe_2O_3$ nanorod: 1) temperature, 2) the rate of mechanical compression, and 3) the rate of mechanical torsion.

Ultrahigh supercapacitance in cobalt oxide nanorod film grown by oblique angle deposition technique

  • Kannan, V.;Choi, Jong-Hyeok;Park, Hyun-Chang;Kim, Hyun-Seok
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1399-1402
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    • 2018
  • Nanorod films of cobalt oxide ($Co_3O_4$) have been grown by a unique oblique angle deposition (OAD) technique in an e-beam evaporator for supercapacitor electrode applications. This technique offers a non-chemical route to achieve large aspect ratio nanorods. The fabricated electrodes at OAD $80^{\circ}$ exhibited a specific capacitance of 2875 F/g. The electrochemically active surface area was $1397cm^{-2}$, estimated from the non-Faradaic capacitive current region. Peak energy and power densities obtained for $Co_3O_4$ nanorods were 57.7 Wh/Kg and 9.5 kW/kg, respectively. The $Co_3O_4$ nanorod electrode showed a good endurance of 2000 charge-discharge cycles with 62% retention. The OAD approach for fabricating supercapacitor nanostructured electrodes can be exploited for the fabrication of a broad range of metal oxide materials.

Size dependent torsional vibration of a rotationally restrained circular FG nanorod via strain gradient nonlocal elasticity

  • Busra Uzun;Omer Civalek;M. Ozgur Yayli
    • Advances in nano research
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    • v.16 no.2
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    • pp.175-186
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    • 2024
  • Dynamical behaviors of one-dimensional (1D) nano-sized structures are of great importance in nanotechnology applications. Therefore, the torsional dynamic response of functionally graded nanorods which could be used to model the nano electromechanical systems or micro electromechanical systems with torsional motion about the center of twist is examined based on the theory of strain gradient nonlocal elasticity in this work. The mathematical background is constructed based on both strain gradient theory and Eringen's nonlocal elasticity theory. The equation of motions and boundary conditions of radially functionally graded nanorods are derived using Hamilton's principle and then transformed into the eigenvalue analysis by using Fourier sine series. A general coefficient matrix is obtained to assemble the Stokes' transformation. The case of a restrained functionally graded nanorod embedded in two elastic springs against torsional rotation is then deeply investigated. The effect of changing the functionally graded index, the stiffness of elastic boundary conditions, the length scale parameter and nonlocal parameter are investigated in detail.

A Reusable Pb2+ Detecting Aptasensor Employing a Gold Nanorod-DNAzyme Conjugate

  • Lee, Jayeon;Ha, Tai Hwan
    • Applied Science and Convergence Technology
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    • v.24 no.5
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    • pp.190-195
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    • 2015
  • Here, we demonstrated a $Pb^{2+}$ detecting aptasensor using $Pb^{2+}$-sensitive DNAzyme-conjugated gold nanorods (GNRs). Fluorescent DNA substrates that were initially quenched by GNRs, are released in response to $Pb^{2+}$ ions to give a substantial fluorescence signal. The GNR-tethered DNAzyme is reusable at least three times with a LOD of 50 nM.