[en] The magnetoresistance (MR) of bulk graphite with different particle sizes is investigated. The MR of the graphite decreases with the particle size decreases. The graphite with micro-sized particles has a positive MR and exhibits positive linear field dependence of MR at about 50 K, whereas the graphite with particle size of 30.2 nm has a negative MR and exhibits negative linear field dependence of MR at about 25 K. The possible mechanism for the MR of graphite can be partially understood using ordinary MR theory, weak localization theory and diffuse scattering theory

[en] A large positive magnetoresistance (MR) has been found in micro-sized Ni_x-C_1-x granular composites. Ni₂₀-C₈₀ composite has the largest MR of 44.1% and 138.5% at room temperature and 5 K under a magnetic field of 5 T, respectively. The magnetic field dependence of the MR can be approximately described as MR∝Bⁿ, and the value of n is determined by the Ni concentration and temperature, ranging from 1/4 to 3/2. It is found that every Ni_x-C_1-x specimen under study has a linear field dependence of the positive MR at a special temperature. The possible mechanism for the positive MR of Ni_x-C_1-x composites has been discussed

[en] Positive magnetoresistance (MR) has been found in Co_x-C_1-x composites (x=10, 20, 30 and 60 wt%) with an average particle size of 23.5 μm. The composite shows a linear field dependence of the MR at higher magnetic fields (3 T< B<8 T) with no saturation of the MR even at B=8 T at room temperature. Among the Co_x-C_1-x composites, Co₁₀-C₉₀ has the largest MR value of 58.9% at room temperature with B=8 T and the MR value of 105.6% at a temperature of 5 K with B=5 T. The possible mechanism for the positive MR is discussed

[en] A large positive magnetoresistance (MR) has been found in micro-sized Fe_x-C_1-x composites. At a magnetic field of 5 T, the Fe_0.2-C_0.8 composite has the largest MR, 53.8% and 190% at room temperature and at 5 K, respectively. The magnetic field dependence of the MR can be described approximately as MR∝Bⁿ, and the value of exponent n is determined by the Fe weight concentration and temperature, ranging from 1/4 to 6/4. It appears that Fe_x-C_1-x has a linear field dependence of the positive MR at different temperatures. The possible mechanism for the positive MR is discussed

[en] Considering the carbon nanotubes' (CNTs) orientation distribution a new model of effective thermal conductivity of CNTs-based composites is presented. Based on Maxwell theory, the formulae of calculating effective thermal conductivity of CNTs-based composites are given. The theoretical results on the effective thermal conductivity of CNTs/oil and CNTs/decene suspensions are in good agreement with the experimental data. The model is valid for the transport properties of the CNTs-based composites