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Abstract  

The lattice specific heat in carbon nanotubes is evaluated within the microscopic model proposed by Mahan and Jeon, published in the Physical Review B, in 2004. Phonons are considered for single wall carbon nanotubes in armchair configuration. As expected, low temperature and high temperature regions show different behaviour of specific heat. Carbon nanotubes are also displaying a very interesting lattice transport depending on the tube diameter, with high thermal conductivities for small diameters.

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, and automation by adding a sorbent to the extract to remove matrix contaminants. Recently, DSPE has been successfully used to purify liquid samples and extracts [ 16–19 ]. Here, single-walled carbon nanotubes (SWNTs) were prepared by an arc discharge

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Journal of Thermal Analysis and Calorimetry
Authors:
A. Andreescu
,
Adriana Savin
,
Rozina Steigmann
,
Nicoleta Iftimie
,
E. Mamut
, and
R. Grimberg

Abstract  

This paper presents a model for evaluation of effective thermal conductivity for the composites with carbon nanotubes (CNT) having log-normal function of distribution of CNT, with direct effect over depolarization factor. The CNT are considered having cylindrical shape with L/d ratio very high. The model parameters are calculated in function of the data from literature. The influence of volume fraction of reinforced materials, of the aspect ratio of the particles included and of the ratio of the two thermal conductivities is presented.

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Abstract  

Pyrolytic decomposition of acetylene over the surface of nickel-, cobalt- and iron-containing ordered mesoporous MCM-41 silicas has been studied. Catalytically active matrices have been prepared by chemisorption of volatile metal acetylacetonate complexes on the silica surface. Reduction of the supported metal-containing compounds was carried out in hydrogen or acetylene atmosphere. Acetylene is used not only as a source of carbon in synthesis of the nanostructures but also as a reagent capable of reducing metal ions in the surface chemical compounds. Formation of carbon nanotubes and nanofibers is shown to depend on the pyrolysis conditions.

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Abstract  

Carbon nanotubes (CNTs) were synthesized using a chemical vapour deposition (CVD) method. The properties of CNTs before and after vacuum annealing treatment were studied using scanning electron microscopy (SEM), scanning tunneling microscopy/spectroscopy (STM/STS) and thermogravimetric analysis (TG). Field emission characteristics of the raw and vacuum heated (up to 650C) carbon nanotube films (CNTFs) were measured in a diode system. Emissive properties of the CNTFs depend on an annealing process during which structural changes in the nanotube walls take place. The structural changes, related to saturation of dangling bonds, influence a rate of oxidation process and also improve the emissive field properties.

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Journal of Thermal Analysis and Calorimetry
Authors:
Eudes Lorençon
,
Rodrigo G. Lacerda
,
Luiz O. Ladeira
,
Rodrigo R. Resende
,
André S. Ferlauto
,
Ulf Schuchardt
, and
Rochel M. Lago

Introduction Carbon nanotubes (CNTs) have been intensely investigated due to their unique chemical, mechanical, and electrical behavior. The inherent properties of CNTs make them versatile supports for metallic nanoparticles

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, the multi-wall carbon nanotube (MWNT) and the single-wall carbon nanotube (SWNT). A SWNT is a graphene sheet rolled into a cylinder with typical diameter on the order of 1.4 nm. However, a MWNT consists of several concentric cylinders with diameters

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Journal of Thermal Analysis and Calorimetry
Authors:
F. Xu
,
L. Sun
,
J. Zhang
,
Y. Qi
,
L. Yang
,
H. Ru
,
C. Wang
,
X. Meng
,
X. Lan
,
Q. Jiao
, and
F. Huang

Abstract  

Heat capacities of the carbon nanotubes (CNTs) with different sizes have been measured by modulated temperature differential scanning calorimetry (MDSC) and reported for the first time. The results indicated the values of C p increased with shortening length of CNTs when the diameters of CNTs were between 60 and 100 nm. However, the values of C p of CNTs were not affected by their diameter when the lengths of CNTs were 1–2 um, or not affected by the length of CNTs when their diameters were below 10 nm. The thermal stabilities of the CNTs have been studied by TG-DTG-DSC. The results of TG-DTG showed that thermal stabilities of CNTs were enhanced with their diameters increase. With lengths increase, the thermal stabilities of CNTs increased when their diameters were between 60 and 100 nm, but there is a slight decrease when their diameters were less than 60 nm. The further DSC analyses showed both released heat and T onset increased with the increase of CNTs diameters, which confirms the consistency of the results from both TG-DTG and DSC on CNTs thermal stability.

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fracture toughness, is trying to be solved by adding carbon nanotubes (CNT). This is expected to improve the mechanical and thermal behaviour of the epoxy resins, increasing also their electrical conductivity [ 1 – 3 ]. However, in the last years, it was

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single-walled carbon nanotubes (SWCNTs) characterization since their discovery in 1993 by Iijima [ 8 ]. It has been widely used to study the stability of SWCNT in an inert (e.g., Ar, N 2 ) or oxidizing atmosphere (e.g., O 2 , CO 2 ) at different

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