Showing papers in "Carbon in 1995"

TL;DR: In this paper, X-ray photoelectron spectroscopy (XPS) was used to investigate the fate of nitrogen functional forms present in a lignite and its chars, derived from the model compounds acridine, carbazole and polyacrylonitrile (PAN).

TL;DR: In this paper, the tensile and bending stiffness constants of ideal multi-walled and single-wall carbon nano-tubes are derived in terms of the known elastic properties of graphite.

TL;DR: In this article, a comparative study of the intensity, bandwidth and frequency shifts of the D and G bands, as well as the broad amorphous feature, is presented, and a curve fitting method is also proposed in order to improve the accuracy in determining the spectroscopic parameters of the main Raman bands.

TL;DR: In this paper, the symmetry properties of carbon nanotubes for both symmorphic and non-symmorphic tubules which have screw-axis symmetry are discussed. And the implications of symmetry on the vibrational and electronic structure of 1D carbon nanite systems are considered.

TL;DR: In this paper, the influence of the oxidation degree on the appearance and evolution of new chemical groups in graphite oxides has been analyzed, which confirm the existence of hydroxyl, carbonyl, ether, epoxy, and peroxy groups in the more oxidized samples.

TL;DR: In this paper, the binding energy of surface groups on several nitrogen-containing activated carbons was investigated and it was shown that the modification method governs the type of nitrogen function formed: ammoxidation leading to amides, animation to lactams and imides and further heat treatment to pyridine and pyrrole groups.

TL;DR: In this article, the vibrational modes of carbon nanotubes are reviewed and the number of these modes is found to depend on the tubule symmetry and not on the diameter.

TL;DR: In this article, four series of activated carbon have been prepared from carbonized olive stones, one of them using carbon dioxide as activating agent and the other three, series AV, W, and H, with water vapor under different experimental conditions.

TL;DR: In this article, the surface composition of the as-received fibers is heterogeneous and undergoes significant changes upon nitric acid exposure, and the net effect of these surface treatments appears to be the systematic and preferential formation of carbonyl and carboxyl groups.

TL;DR: In this paper, a mechanism for the pyrolysis of carbon/phenolic composites is proposed, which describes the resin reaction as occurring in three major reaction regions: formation of additional crosslinks, breaking of the crosslinks and stripping of the aromatic rings.

TL;DR: In this paper, a hollow graphitic cage was used to encapsulate rare-earth and iron-group metals by using an electric arc discharge and showed the excellent protection of outer graphitic cages against oxidation of the inner materials.

TL;DR: In this article, the structure of as-grown and heat-treated pyrolytic carbon nanotubes (PCNTs) is discussed on the basis of a possible growth process.

TL;DR: In this article, the authors discuss the use of helical symmetry for the electronic structure of carbon nanotubes and the resulting trends in both band gap and strain energy versus nanotube radius, using both empirical and first-principles techniques.

TL;DR: In this article, three series of activated carbon have been prepared by heat treatment of peach stones impregnated with solutions of phosphoric acid, in order to analyze the effect of PHO on the yield, bulk density and porosity of the resultant activated carbons.

TL;DR: In this paper, the changes of precursor functionalities and transformation of nitrogen structures at 600 and 800 °C were determined by X-ray photoelectron spectroscopy, and from all precursors, three types of nitrogen structure were obtained: pyrrolic, pyridinic and quaternary.

TL;DR: In this article, NMR and FTIR analyses have been employed to follow the evolution of chemical structure in relation to porosity development, as a function of heat treatment temperature (HTT), for activated carbons produced from white oak by phosphoric acid activation.

TL;DR: In this article, the carbonization resulting from an intumescence phenomenon of the fire-retardant formulation: ethylene terpolymer-ammonium polyphosphate/pentaerythritol was studied.

TL;DR: In this article, the presence and significance of these defects in carbon nanotubes are discussed and it is clear that some nanotube properties, such as their conductivity and band gap, will be strongly affected by such defects and that the interpretation of experimental data must be done with great caution.

TL;DR: In this article, the effects of aqueous NaOH treatment after oxidation on the mechanical properties (tensile strength, Izod IS, IFSS, and ILSS) of fibers and their composites were also investigated.

TL;DR: In this article, the surface functional groups of ultradispersed diamond (UDD) powders synthesized by explosive detonation were studied by FTIR to explore their surface functional group and the results indicated that several types of carbonyl groups are predominant on the surface of UDD powders.

TL;DR: In this article, the authors discuss the energy and formation mechanism of multi-shell fullerenes and propose an efficient production method based on high-resolution electron microscopy (HREM) observations.

TL;DR: In this paper, the relationship between the structure and mechanical properties of both polyacrylonitrile (PAN) and pitch-based carbon fibres has been studied in detail.

TL;DR: A review on the gasification of carbonaceous materials by oxygen-containing reactant molecules is given in this paper, with the emphasis on the attempt to unify the mechanistic description of gasification process.

TL;DR: In this article, carbon nanotubules were produced in a large amount by catalytic decomposition of acetylene in the presence of various supported transition metal catalysts and the influence of different parameters such as the nature of the support, the size of active metal particles and the reaction conditions on the formation of nanotubes was studied.

TL;DR: In this article, the adsorption capacity of the activated carbons depended on the surface area and porosity of the carbon, the solubility of the phenolic compound, and the hydrophobicity of the substituent.

TL;DR: In this paper, the influence of surface chemistry and metal precursor species on the properties of Pt/C catalysts has been analyzed and the effect of these parameters in the final metal dispersion has also been investigated.

TL;DR: In this article, Boron nitride (BN), derived from borazine oligomers, was examined as a means of enhancing the oxidation resistance of carbon fiber-carbon matrix composites (CC).

TL;DR: In this article, two methods have been employed to prepare boron-doped carbon materials: ion implantation and CVD to dope the surface region of vitreous carbon with up to 12 to 15 atomic % borons.

TL;DR: In this paper, the reactivity of fine-weave pierced 3D carbon-carbon composites in air at temperatures up to 3000 °C was studied, and corrosion morphology and microstructure of oxidized samples were investigated by XPS, SEM, and XRD techniques, and the nonequilibrium nature of the oxidation process was pointed out.

TL;DR: In this article, an activated carbon fiber containing mesopores was attempted by catalytic activation using cobalt and the cobalt accelerated activation of the fiber in steam catalytically to form mesopore preferentially.