Carbon
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Experimental data for n-pentane adsorbed on BPL activated carbon in a nitrogen environment are reported at ultra-low concentrations into the Henry’s law region. We introduce two methods to prepare pre-equilibrated samples at known loadings. The samples were analyzed by a purge and trap method. Adsorption data were measured at loadings from 1.0 to 0.0001molkg −1 and pressures of 6 to 5×10 ...
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The G-band and the G′-band (∼2600–2700cm −1 ) Raman spectra of single walled carbon nanotubes (SWCNTs) in a sodium dodecyl sulphate aqueous solution were investigated as a function of sonication energy density (ρ). The relative intensity of the G-band feature around ∼1520–1560cm −1 (G − ) and the linewidth (Γ) of the G′-band decrease monotonically with ρ where the former dependence...
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To improve the field emission properties of screen printed carbon nanotube (CNT) films, an Ar neutral beam was used as one of the surface treatment techniques and the CNT field emission characteristics after the treatment were compared with those after Ar ion beam treatment. The Ar neutral beam treatment enhanced the field emission properties of the CNTs and by decreasing the turn-on field and by...
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A two-step direct and simple method for the preparation of a hierarchical porous carbon monolith with micropores, mesopores and macropores is described. The two stages give more flexibility in the preparation of a porous carbon monolith. In step I a macroporous interconnected carbon monolith is prepared by ultrasonic irradiation during sol–gel polycondensation. The effects of sol–gel temperature,...
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Multi-wall carbon nanotubes (MWCNTs) were exposed to a CF 4 rf-plasma. X-ray photoelectron spectroscopy analysis shows that the treatment effectively grafts fluorine atoms onto the MWCNTs. The fluorine atomic concentration and the nature of the C–F bond (semi-ionic or covalent) can be tuned by varying the exposure time. Ultraviolet photoelectron spectroscopy analysis confirms that the valence...
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Mesoporous carbon thin films with ordered structures were prepared by using resorcinol–surfactant self-assembly. A mixture of resorcinol, surfactant, and ethanol coated on silicon substrates was exposed to formaldehyde vapor as a cross-linking agent to form structured resorcinol/formaldehyde resin films. The films were then carbonized at 800°C in an inert atmosphere to remove the surfactant and to...
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Vertically aligned multi-walled carbon nanotube (MWCNT) arrays were fabricated on an anodic aluminum oxide membrane bonded to a Si wafer. After obtaining a protruding tip for the MWCNTs by etching away some oxide, they were used as electrodes in the fabrication of carbon nanotube field emitters. Long single-walled carbon nanotubes (SWCNTs) were spin coated on the MWCNT arrays of uniform height. Clean...
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A method for preparing a SiC coating on carbon fibers is presented. The SiC coating was generated from the reaction of silicon monoxide (SiO) with a pyrolytic carbon (PyC) layer deposited on the fibers. The influence of holding time on the microstructure of the SiC layer was discussed. The oxidation behaviors of the uncoated and SiC coated carbon fibers were compared. The formation mechanism of the...
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The growth of carbon nanotubes by a plasma assisted catalytic chemical vapor deposition was investigated using cobalt, nickel and iron catalyst particles of different sizes. For the three catalysts examined, it was shown that the growth mode switches from “tip-growth” for large particles (>>5nm) to “base-growth” for smaller ones (<5nm). While single-walled nanotubes and those with few walls...
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Mixed mode brittle fracture was studied theoretically for two grades of commercial graphite. The results reported previously for the fracture loads were used to calculate the mixed mode fracture resistance of the graphite materials tested by a centrally cracked Brazilian disk specimen. The calculated results show that the experimental data were well above the estimates of well-known mixed mode fracture...
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H. Lu,
J. Goldman,
F. Ding,
Y. Sun,
more
Sliding friction and adhesion properties of vertically aligned multi-walled carbon nanotube (VAMWCNT) arrays and fluoro-nanodiamond (F-ND) films on glass substrate have been quantitatively investigated in current study using atomic force microscopy. It was found that VAMWCNT arrays result in lower friction compared to F-ND films. Friction forces were also found to be consistently higher in nitrogen...
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A dye, as a model for small molecular drug, was inserted into carbon nano test tubes (35nm in diameter, 4.5μm in length) synthesized using nanochannels of an anodic aluminum oxide film as a template, and the open mouths of the test tubes were sealed by polystyrene polymer. The resulting test tubes are dispersible in water, and the dye remains in the cavities because of the sealing. When the polymer-plug...
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The ablation rate of a graphite anode is investigated as a function of anode diameter for a carbon nanotube arc plasma. It is found that anomalously high ablation occurs for small anode diameters. This result is explained by the formation of a positive anode sheath. The increased ablation rate due to this positive anode sheath could imply greater production rate for carbon nanotubes.
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Pyrolysis and carbonization behaviors of fluorinated aromatic polyimide films synthesized from fluorinated dianhydrides and diamines were investigated by thermogravimetric and mass spectrometric measurements. Evolution of fluorine compound gases and related species was observed during the pyrolysis in the temperature range from 450 to 700°C, in addition to the evolution of CO and CO 2 due...
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The effects of an air plasma generated by a dielectric barrier discharge (DBD) on highly oriented pyrolytic graphite (HOPG) have been investigated through scanning tunneling microscopy (STM), Raman and XPS spectroscopies. Three main types of nanometer/atomic scale features were identified by STM: (i) small bumps, attributed to surface atomic vacancies; (ii) smooth bumps, attributed to interstitial...
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Developing corrosion resistant carbon nanotube (CNT) and carbon nanofiber (CNF) supported Pt catalysts with optimized particle size is important for proton exchange membrane fuel cells. We investigated the effects of deposition technique (conventional refluxing and microwave irradiation), water content, carbon support and metal loading on the average Pt particle size and electrochemically active surface...
