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In this paper the thermal conductivities of monocrystal carbon, silicon, and germanium nanometer thin film are simulated respectively using non-equilibrium molecular dynamics (NEMD) method and corresponding Tersoff potential energy function. The simulation results indicate that the thermal conductivities of those nanometer thin films are obviously lower than the corresponding thermal conductivities...
A facile approach to the surface oxidation of multi-walled carbon nanotubes (MWCNTs) is presented using oxidation solution to decorating MWCNTs, sonication to promote this effect and increase the population density of surface oxide groups. The sonication short time for MWCNTs oxidation /functionalization is desirable for minimizing structural damage to the MWCNTs that could lead to changes in their...
Due to the trade secrets and intellectual property, there are still many aspects of MEMS switches which are not understand well and are currently under investigation. In this paper, our report shows that MEMS can be released using O2 and a little carbon powder at the same time. The relationship between the removing polyimide time and the cure temperature is presented using carbon powder in the quartz...
Significant research and development efforts have been devoted to producing reliable glucose sensors for in vitro or in vivo applications, because of high demand for blood glucose monitoring and other application. The outstanding electrochemical properties of carbon nanotubes, along with their high surface area, can promote electron-transfer and enlarge enzyme loading, which provide the available...
Thermal conductivities of single-wall carbon nanotubes (SWNTs) filled with argon (Ar) with types (10, 10) and (15, 15) respectively, are calculated over a temperature range of 500-1200 K using equilibrium molecular dynamics (EMD) simulation method. The Tersoff potential for C-C bonding interactions and the Lennard-Jones (LJ) potential for Ar-C nonbonding interactions are employed. The effects of filled...
Field emission properties of carbon nanotubes (CNTs) filled with single crystalline Cu nanoneedles at their tips have been investigated in situ with an STM-TEM holder. The CNTs are synthesized using an alkali doped Cu catalyst by a thermal chemical vapor deposition method. Experiments show that CNTs filled with Cu have a much lower turn-on voltage (generally lower than 75V) than those without Cu (>...
Single wall carbon nanotubes are fabricated by a long pulse and high power Nd:YAG laser ablation from a solid composite target consisting of graphite and bimetallic catalyst at room temperature without any carrying gas flow. The results demonstrated that the technique could eliminate several processing parameters currently used for SWNT fabrication via laser ablation process. Most importantly, the...
Two kinds of novel zinc/CNT composites were prepared by composite electrodeposition. The codeposition of carbon nanotubes and zinc was verified by the Raman spectrometry analysis. Scanning electron microscopy images illustrated the continuous and uniform zinc coverage on CNT, which were unique interfacial features in the currently known metal/CNT composites
Structural instability of single wall carbon nanotube under electron beam irradiation was investigated by our developed in-situ transmission electron microscopy observation technique. It was observed that the nanotube shrunk and necked in diameter gradually and the curved nanotube shrunk faster in axis direction than straight one with increasing of electron dose during the irradiation. Such athermally...
A novel room temperature synthesis of carbon nanotubes (CNTs) by liquid phase deposition of methanol is firstly reported. Nanotube samples were characterized with field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectroscopy. FESEM micrographs revealed that nanotubes with diameter in the range of 20-200 nm were grown at room temperature. HR-TEM...
Determination of the helicity of carbon nanotubes (CNTs) is useful for CNTs in nanoelectronic device applications. Using electron diffraction to measure chiral angle with a high precision is reviewed, and helix-shaped carbon nanostructures are introduced and characterized by transmission electron microscopy. The possible formation mechanism of helix-shaped CNTs is also referred in the paper
High yields of multi-walled carbon nanotubes are synthesized by chemical vapor deposition of acetylene on palladium nanoparticles supported on porous SiO2. HRTEM results reveal that the carbon nanotubes have novel conical inner structure. By changing the content of palladium in the catalyst, we obtained palladium nanoparticles with different diameter distribution. It was found that the apex angles...
A pyrolytic carbon film electrode was fabricated by the low temperature chemical vapor deposition (CVD) method. This report deals with the preparation and electrochemical behavior of this carbon film. To characterize the surface structure, scanning electron microscopy was applied. Also, cyclic voltammetry and chronocoulometery were applied to evaluate the electrochemical properties
Magnetite (Fe3O4) nanoparticles uniformly loaded on multi-walled carbon nanotubes (MWCNTs) were synthesized by a wet chemistry method, and then carbon coated Fe3C nanoparticles supported by MWCNTs were prepared by heat-treatments subsequently in nitrogen at 600 degC and in acetylene atmosphere at 500 degC. The as-prepared nanoparticles were all single crystals with a size distribution ranging from...
The pyrolyzed polyaniline (PANI) consisted of amorphous hard carbon full of pores. Carbon nanotubes (CNTs) grew on pyrolyzed PANI substrate with the rough surface containing some pores using a low pressure chemistry vapor deposition (LPCVD) method with xylene as a carbon precursor source and Fe/SiO2 nanoparticles as catalyst. The pore extrusion and the deposited carbon particles adhesion of CNTs growing...
Multiwall and singlewall carbon nanotubes were used as precursors for preparing metal ion-decorated nanotubes. The activated nanotubes catalyze metal deposition specifically onto their surfaces upon wetting the surface of nanotubes. K+ , Cu2+ , Mg2+ , Ca2+ and Fe3+ decorated singlewall and multiwall carbon nanotubes, were screened for the catalytic activity in reactive violet dye waste water decomposition...
Carbon nanofibers (CNFs) are synthesized at 450-650degC by a catalytic CVD method using nickel powders reduced from nickel carbonate as catalyst without other supporting materials, and acetylene as carbon source. It is found that the nickel powders present a considerable catalytic efficiency in the growth of the CNFs at the temperature between 500-550degC. TEM observation shows that a large portion...
In order to improve the performance of field emitters nowadays, carbon nanotubes are used instead of conventional materials such as silicon and metals. In this paper, field emission characteristics of three different multi-wall carbon nanotube films have been compared, which are fabricated by different methods, including direct growth, evaporation coating and flow assembly. The field emission current-voltage...
In order to understand the formation mechanism of nano- materials during the arc discharge in liquid, serial experiments were conducted on synthesis of nano-materials by arc discharge both in water and in liquid nitrogen. Previous research showed that the stability of arc discharge affected the nano-products significantly. In this paper, the cross magnetic field (CMF) was introduced to disturb the...
Development and preliminary characterization on the performance of a micro-bubble generator using carbon nanotubes (CNTs) as heating elements are presented. Dielectrophoretic force was used to align CNTs between fabricated micro-electrodes. The contacts between the CNTs and electrodes were fixed by patterned SiO2 thin film. Localized high temperature due to Joule-heating generated by an AC current...
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