共查询到20条相似文献,搜索用时 0 毫秒
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《Materials science & engineering. C, Materials for biological applications》2006,26(5-7):1189-1193
Well aligned multi-walled carbon nanotubes were synthesized at atmospheric pressure using a microwave plasma torch on silicon substrates with silicon oxide buffer layer and catalyst overlayer in the mixture of argon, hydrogen and methane. Iron or nickel was used as catalysts. The optimum substrate temperature for the deposition on Si/SiO2/Fe substrates was about 970 K. In this case SEM micrographs of the deposits revealed a presence of vertically aligned nanotubes with the diameters around 15 nm. TEM micrographs showed a presence of amorphous carbon particles in the samples and some defects in the wall structure of the produced nanotubes. In Raman spectra two peaks at 1332 and 1584 cm−1 were observed. The CNTs were also synthesized on the substrates without SiO2 buffer layer but their quality was lower. The synthesis with Ni instead of Fe catalyst required lower temperature and the alignment of the nanotubes was worse. The deposition process was monitored by optical emission spectroscopy. Atomic lines of hydrogen and argon, an emission of CN due to a presence of nitrogen impurities from atmosphere, a weak molecular band of CH and strong C2 emission were detected in the spectra. 相似文献
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Aneta Fraczek-Szczypta Maciej Bogun Stanislaw Blazewicz 《Journal of Materials Science》2009,44(17):4721-4727
Carbon nanotubes were used to modify a polyacrylonitrile (PAN) polymer solution before the manufacture of the carbon fiber
precursor. The modified PAN fibers were spun from a dimethylformamide solution containing a small amount of single-walled
carbon nanotubes. The fibers were characterized by thermogravimetry and optical and scanning electron microscopy. Structure,
morphology, and selected properties of the composite polymeric fibers and the fibers after carbonization are characterized.
The mechanical properties of the fibers are examined. It is found that nanotubes in the PAN solution have a strong tendency
to form agglomerates that inhibit suitable macromolecular chain orientation of the carbon fiber precursor. Fibers manufactured
from such a solution have similar mechanical properties to those from a pure PAN precursor, and after carbonization the resultant
carbon fibers are very weak. A comparison of pure carbon fibers and those containing nanotubes reveals slight differences
in their structural ordering. 相似文献
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Carbon nanotubes loaded with magnetic particles 总被引:1,自引:0,他引:1
Korneva G Ye H Gogotsi Y Halverson D Friedman G Bradley JC Kornev KG 《Nano letters》2005,5(5):879-884
We describe a simple and versatile technique to produce magnetic tubes by filling carbon nanotubes (CNTs) with paramagnetic iron oxide particles ( approximately 10 nm diameter). Commercial ferrofluids were used to fill CNTs with an average outer diameter of 300 nm made via chemical vapor deposition into alumina membranes. Transmission electron microscopy study shows a high density of particles inside the CNT. Experiments using external magnetic fields demonstrate that almost 100% of the nanotubes become magnetic and can be easily manipulated in magnetic field. These one-dimensional magnetic nanostructures can find numerous applications in nanotechnology, memory devices, optical transducers for wearable electronics, and in medicine. 相似文献
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Biomimetic synthesis: Double-walled silica nanotubes 总被引:1,自引:0,他引:1
Brunner E 《Nature materials》2007,6(6):398-399
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The rational selection and assembly of materials are central issues in the development of energy conversion and storage applications. Incorporating the utilization of carbon nanotubes cathode and TiO2 nanotubes anode in energy storage, a nonaqueous hybrid supercapacitor was developed in order to significantly increase the energy density of the supercapacitor. The electrochemical performance of the hybrid supercapacitor is characterized by charge/discharge test and cyclic voltam-mograms. According to the voltage value, the energy density of the asymmetric supercapacitor, by applying a potential varying from 0 to 2.8 V, is found to be 14.4 Wh/kg at upwards of 10 C, which is twice more than for the conventional symmetric supercapacitor utilizing carbon nanotubes, while maintaining desirable cycling stability and rate capability. 相似文献
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Using facile diazonium chemistry, sulfonate groups have been covalently attached to single wall carbon nanotubes. The resulting sulfonated tubes form a stable aqueous dispersion in the presence of pyrrole monomer. Subsequent electropolymerisation results in a conductive, electroactive polypyrrole doped with sulfonated tubes being formed at unusually low potentials. The potential of this material as a host matrix for biomolecules has been demonstrated by entrapping horse-radish peroxidase directly in the polypyrrole during composite formation. 相似文献
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Kermanpur A Dastjerdi VH Ghassemali E Abbasi MH 《Journal of nanoscience and nanotechnology》2010,10(9):6222-6225
In this work, nanoporous titania top layers were deposited by dip-coating process on microporous alpha-alumina substrates using the sol-gel process. The alumina substrates were synthesized by slip casting method using Taguchi optimising approach. The microporous substrate was then used to coat nanoporous titania layers by the sol-gel method. The thickness, pore size, structure and permeability of the membranes were characterised using SEM, XRD, STA and Hg-Porosimetry. The process conditions to achieve defect-free nanoporous titania layers with the average pore size of about 4 nm coated on the microporous alumina substrates with the average pore size of about 270 nm were determined. 相似文献
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AbstractThe nature of mechanical strain mediated electromagnetic coupling in multiferroic composites has been studied extensively in recent years. This review is on composites with ferromagnetic or ferrimagnetic oxides and ferroelectrics. Systems studied so far include samples with spinel ferrites, hexagonal ferrites or lanthanum manganites for the ferromagnetic phase and barium titanate, lead zirconate titanate (PZT), lead magnesium niobate–lead titanate (PMN-PT) or lead zinc niobate–lead titanate (PZN-PT) for the ferroelectric phase. Bilayer and multilayer heterostructures, bulk composites, core shell nanoparticles and core shell nanotubes and nanowires were investigated for their response to magnetic fields, termed direct magnetoelectric effect (DME). Several systems show a giant low frequency DME and resonance enhancement at bending and electromechanical resonance. The response of the composites to an electric field, called converse ME effect, is found to be strong in several ferrite–ferroelectric composites. The potential for use of the composites for pico-Tesla magnetic sensors and high frequency electric field tunable ferrite signal processing devices are also addressed in this review. 相似文献
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Usui Y Aoki K Narita N Murakami N Nakamura I Nakamura K Ishigaki N Yamazaki H Horiuchi H Kato H Taruta S Kim YA Endo M Saito N 《Small (Weinheim an der Bergstrasse, Germany)》2008,4(2):240-246
Carbon nanotubes (CNTs) have been used in various fields as composites with other substances or alone to develop highly functional materials. CNTs hold great interest with respect to biomaterials, particularly those to be positioned in contact with bone such as prostheses for arthroplasty, plates or screws for fracture fixation, drug delivery systems, and scaffolding for bone regeneration. Accordingly, bone-tissue compatibility of CNTs and CNT influence on bone formation are important issues, but the effects of CNTs on bone have not been delineated. Here, it is found that multi-walled CNTs adjoining bone induce little local inflammatory reaction, show high bone-tissue compatibility, permit bone repair, become integrated into new bone, and accelerate bone formation stimulated by recombinant human bone morphogenetic protein-2 (rhBMP-2). This study provides an initial investigational basis for CNTs in biomaterials that are used adjacent to bone, including uses to promote bone regeneration. These findings should encourage development of clinical treatment modalities involving CNTs. 相似文献
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