scholarly journals Effect of Catalyst Film Thickness on Growth Morphology, Surface Wettability and Drag Reduction Property of Carbon Nanotubes

2016 ◽  
Vol 35 (9) ◽  
pp. 857-863 ◽  
Author(s):  
Weiwei Ma ◽  
Zhiping Zhou ◽  
Gang Li ◽  
Ping Li
Keyword(s):  
Carbon Nanotubes ◽  
Drag Reduction ◽  
Great Influence ◽  
Surface Wettability ◽  
Silicon Substrates ◽  
Practical Application ◽  
Growth Morphology ◽  
Nickel Films ◽  
Catalyst Film ◽  
Reduction Property

AbstractNickel films were deposited on silicon substrates using magnetron sputtering method. The pretreatment process of nickel films under high temperature and ammonia atmosphere was investigated. The thickness of nickel film has a great influence on growth morphology of carbon nanotubes (CNTs). Too large or too small thickness would do harm to the orientated growth of CNTs. The inner structure, elements composition and growth mechanism have been confirmed by TEM and EDX characterization. The surface wettability and drag reduction property of CNTs were investigated. This paper can provide a new, effective method to further develop the practical application in micro/nano devices field.

Carbon nanotubes grown on different-sized rectangular patterns

2004 ◽  
Vol 19 (6) ◽  
pp. 1803-1807 ◽  
Author(s):  
Lujun Pan ◽  
Yoshikazu Nakayama ◽  
Hideki Shiozaki ◽  
Chikashi Inazumi
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Line Width ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Surface Shape ◽  
Iron Film ◽  
Nucleation Process ◽  
Catalyst Film ◽  
Field Emission Displays

Carbon nanotubes have been synthesized by chemical vapor deposition using a thin iron film as catalyst on the silicon substrate with different-sized rectangular patterns. It is found that the carbon nanotubes grow vertically to the substrate in a high density with a surface shape similar to that of the substrate when the line width of the patterns are larger than 1 μm, However, when the line width of the pattern is reduced to below 0.5 μm, carbon nanotubes cannot grow vertically anymore. This phenomenon might be caused by the relaxation of stress in catalyst film and the coalescence of the catalyst clusters to form particles or grains, which contributes to the migration of catalyst from edge to inner part during the nucleation process. These results are very useful for the fabrication of field-emission displays and other devices using patterned carbon nanotubes.

Synthesis of Superhydrophobic Titanium-based Material with Efficient Drag-reduction Property

2016 ◽  
Vol 45 (8) ◽  
pp. 901-903
Author(s):  
Zhaoguo Zhang ◽  
Zhengfeng Huang ◽  
Xudong Cheng ◽  
Qingli Wang ◽  
Peimei Dong ◽  
...  
Keyword(s):  
Drag Reduction ◽  
Reduction Property

Fabrication and electrochemical characterization of super-capacitor based on three-dimensional composite structure of graphene and a vertical array of carbon nanotubes

2018 ◽  
Vol 52 (22) ◽  
pp. 3039-3044 ◽  
Author(s):  
Daniel Choi ◽  
Eui-Hyeok Yang ◽  
Waqas Gill ◽  
Aaron Berndt ◽  
Jung-Rae Park ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Vapor Deposition ◽  
Composite Structure ◽  
Graphene Layer ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Silicon Substrates ◽  
Vertical Array ◽  
Pressure Chemical

We have demonstrated a three-dimensional composite structure of graphene and carbon nanotubes as electrodes for super-capacitors. The goal of this study is to fabricate and test the vertically grown carbon nanotubes on the graphene layer acting as a spacer to avoid self-aggregation of the graphene layers while realizing high active surface area for high energy density, specific capacitance, and power density. A vertical array of carbon nanotubes on silicon substrates was grown by a low-pressure chemical vapor deposition process using anodized aluminum oxide nanoporous template fabricated on silicon substrates. Subsequently, a graphene layer was grown by another low-pressure chemical vapor deposition process on top of a vertical array of carbon nanotubes. The Raman spectra confirmed the successful growth of carbon nanotubes followed by the growth of high-quality graphene. The average measured capacitance of the three-dimensional composite structure of graphene-carbon nanotube was 780 µFcm−2 at 100 mVs−1.

Mechanical Impact Effects of Fluid Hammer Effects on Drag Reduction of Coiled Tubing

2021 ◽  
pp. 1-10
Author(s):  
Yongsheng Liu ◽  
Xing Qin ◽  
Yuchen Sun ◽  
Zijun Dou ◽  
Jiansong Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Drag Reduction ◽  
Flow Rate ◽  
Fluid Velocity ◽  
Fluid Pressure ◽  
Great Influence ◽  
Radial Force ◽  
Fluid Flow Rate ◽  
Normal Contact ◽  
Coiled Tubing

Abstract Aiming at the oscillation drag reduction tool that improves the extension limit of coiled tubing downhole operations, the fluid hammer equation of the oscillation drag reducer is established based on the fluid hammer effect. The fluid hammer equation is solved by the asymptotic method, and the distribution of fluid pressure and flow velocity in coiled tubing with oscillation drag reducers is obtained. At the same time, the axial force and radial force of the coiled tubing caused by the fluid hammer oscillator are calculated according to the momentum theorem. The radial force will change the normal contact force of the coiled tubing which has a great influence on frictional drag. The results show that the fluid flow rate and pressure decrease stepwise from the oscillator position to the wellhead position, and the fluid flow rate and pressure will change abruptly during each valve opening and closing time. When the fluid passes through the oscillator, the unit mass fluid will generate an instantaneous axial tension due to the change in the fluid velocity, thereby converting the static friction into dynamic friction, which is conducive to the extend limit of coiled tubing.

scholarly journals Wet chemistry route for the decoration of carbon nanotubes with iron oxide nanoparticles for gas sensing

2019 ◽  
Vol 10 ◽  
pp. 105-118 ◽  
Author(s):  
Hussam M Elnabawy ◽  
Juan Casanova-Chafer ◽  
Badawi Anis ◽  
Mostafa Fedawy ◽  
Mattia Scardamaglia ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Gas Sensing ◽  
Oxide Nanoparticles ◽  
Silicon Substrates ◽  
Iron Salt ◽  
Multiwalled Carbon ◽  
Wet Chemistry ◽  
Gas Sensing Properties

In this work, we investigated the parameters for decorating multiwalled carbon nanotubes with iron oxide nanoparticles using a new, inexpensive approach based on wet chemistry. The effect of process parameters such as the solvent used, the amount of iron salt or the calcination time on the morphology, decoration density and nanocluster size were studied. With the proposed approach, the decoration density can be adjusted by selecting the appropriate ratio of carbon nanotubes/iron salt, while nanoparticle size can be modulated by controlling the calcination period. Pristine and iron-decorated carbon nanotubes were deposited on silicon substrates to investigate their gas sensing properties. It was found that loading with iron oxide nanoparticles substantially ameliorated the response towards nitrogen dioxide.

In Situ Filling of Fe/Ni Oxide Nanowire into Carbon Nanotubes Doped with Nitrogen in CH4/H2/Air Plasma

2011 ◽  
Vol 15 ◽  
pp. 51-56 ◽  
Author(s):  
Xin Wang ◽  
Ya Yu Wang ◽  
Wei Tao Zheng ◽  
Zan Wang
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor ◽  
Air Plasma ◽  
Catalyst Film ◽  
Metal Oxide Nanoparticle ◽  
Transmission Electron ◽  
Nitrogen Doped Carbon ◽  
Ni Oxide

Nitrogen-doped carbon nanotubes (N-CNTs) were synthesized using air as the nitrogen carrier gas and CH4 as the carbon source by plasma-enhanced chemical vapor deposition over a thin catalyst film of Fe50Ni50. Transmission electron microscopy and high resolution transmission electron microscopy measurements have indicated that the N-CNTs grew with a tip-type growth mode. When H2 was added to the CH4/air plasmas during the N-CNTs growth stage, it was found that Fe/Ni oxide nanowire was filled into the nanotube. However, without adding H2 in the CH4/air mixture plasma, only metal oxide nanoparticle was found on the tip of the N-CNT.

Controlling growth and field emission property of aligned carbon nanotubes on porous silicon substrates

1999 ◽  
Vol 75 (4) ◽  
pp. 481-483 ◽  
Author(s):  
Dongsheng Xu ◽  
Guolin Guo ◽  
Linlin Gui ◽  
Youqi Tang ◽  
Zujin Shi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Porous Silicon ◽  
Field Emission ◽  
Emission Property ◽  
Field Emission Property ◽  
Silicon Substrates ◽  
Aligned Carbon Nanotubes
Sign in / Sign up

Export Citation Format

Share Document