Fitting the experimental data into the general effective media (GEM) equation, a theoretical percolation curve was gained. A mathematical model was proposed which is based on the GEM equation and the dilution effect of filler volume fraction due to thermal volume expansion.

This process has potential to excellent performance PTCR. By research on the relation between resistivity and metal volume fraction of composites, it is concluded that Ni particles and (Ba,Sr)TiO3 particles are even distributed in composites which resistance pattern is series & parallel one and agrees with GEM equation.

The electrical conductivity of v2o3-polymer composites were studied by examining the dependence of resistivity(conductivity)on the volume fraction of v2o3.The experimental data(ρm vs Φ)were fitted using computer to GEM equation to a satisfactory accuracy.

It is concluded by GEM equation that the total resistance of the composite made of metal particles and ceramic particles almost agree with the series and parallel circuit rule, which can be calculated from the e-quation,.

Fitting the experimental data into the general effective media (GEM) equation, a theoretical percolation curve was gained. A mathematical model was proposed which is based on the GEM equation and the dilution effect of filler volume fraction due to thermal volume expansion.

This process has potential to excellent performance PTCR. By research on the relation between resistivity and metal volume fraction of composites, it is concluded that Ni particles and (Ba,Sr)TiO3 particles are even distributed in composites which resistance pattern is series & parallel one and agrees with GEM equation.

The electrical conductivity of v2o3-polymer composites were studied by examining the dependence of resistivity(conductivity)on the volume fraction of v2o3.The experimental data(ρm vs Φ)were fitted using computer to GEM equation to a satisfactory accuracy.

It is concluded by GEM equation that the total resistance of the composite made of metal particles and ceramic particles almost agree with the series and parallel circuit rule, which can be calculated from the e-quation,.

AC impedance spectroscopy was used to evaluate the DC conductivity of Portland cement mortar and silica fume containing cement mortar with single sized graphite as aggregate.

quantitative analysis on the PTC effect of metal-ceramic composites is made with theeffective media theory. By the general effective media(GEM) equation for metal-ceramic twophase system,the conductivity of the composite medium(σm)as a function of the conductivi-ty of the two phases(σ1 and σh)is derived and found to be in fairly good agreement with thatobtained experimentally and other relevant dat.

Preliminary models, also based on the GEM equation, are used to describe the positive temperature coefficient of resistivity (PTC) and the piezoresistivity (uniaxial pressure) of the composite when the composition is near the percolation threshold.

The experimental data (ρm versus φ) were fitted (using a computer program) to the GEM equation with satisfactory accuracy.

The experimental data can be well fitted to the GEM equation.

The ac conductivity of silicon-polyester resin composites is found to be best fitted using the two exponent phenomenological percolation equation (TEPPE) (formerly known as the general effective media (GEM) equation).

The two fitting parameters in the GEM equation are rh and k.

The electrical conductivity of v2o3-polymer composites were studied by examining the dependence of resistivity(conductivity)on the volume fraction of v2o3.The experimental data(ρm vs Φ)were fitted using computer to GEM equation to a satisfactory accuracy. The critical volume fration Φ c and other parameters,t,σh and σ1 evaluted by fitting,and LΦ and Lf,calculated after fitting were analysed by taking into account the geometry,the orientation and the arrangement of two components.The physical meanings of LΦ,Lf...

The electrical conductivity of v2o3-polymer composites were studied by examining the dependence of resistivity(conductivity)on the volume fraction of v2o3.The experimental data(ρm vs Φ)were fitted using computer to GEM equation to a satisfactory accuracy. The critical volume fration Φ c and other parameters,t,σh and σ1 evaluted by fitting,and LΦ and Lf,calculated after fitting were analysed by taking into account the geometry,the orientation and the arrangement of two components.The physical meanings of LΦ,Lf and t were further illustrated on the basis of their definitions.

quantitative analysis on the PTC effect of metal-ceramic composites is made with theeffective media theory.By the general effective media(GEM) equation for metal-ceramic twophase system,the conductivity of the composite medium(σm)as a function of the conductivi-ty of the two phases(σ1 and σh)is derived and found to be in fairly good agreement with thatobtained experimentally and other relevant dat.

AC impedance spectroscopy was used to evaluate the DC conductivity of Portland cement mortar and silica fume containing cement mortar with single sized graphite as aggregate. The experimental conductivity against aggregate volume fraction data were fitted accurately to GEM equation with two percolation morphology parameters, critical aggregate volume fraction φ hc and an exponent t , which are 0.38 and 1.48～1.68 respectively. The fitted critical volume fraction differs from that deduced from the...

AC impedance spectroscopy was used to evaluate the DC conductivity of Portland cement mortar and silica fume containing cement mortar with single sized graphite as aggregate. The experimental conductivity against aggregate volume fraction data were fitted accurately to GEM equation with two percolation morphology parameters, critical aggregate volume fraction φ hc and an exponent t , which are 0.38 and 1.48～1.68 respectively. The fitted critical volume fraction differs from that deduced from the site percolation threshold, and the exponent is hydration time dependent. It is concluded that the partial wetting of aggregate particles by cement paste and the existence of transition zone are responsible for the effect on these two GEM equation parameters.