In the light of fractal geometry theory, the characteristics of coal's electric parameters (including dielectric constant, alternating conductivity, dielectric loss angle tangent and electric polarization constant...In the light of fractal geometry theory, the characteristics of coal's electric parameters (including dielectric constant, alternating conductivity, dielectric loss angle tangent and electric polarization constant) were studied by using literature data. The results are shown that the electrical properties of coal have fractal characteristic. The fractal dimensions of dielectric, alternating conductivity, dielectric loss angle tangent were obtained, and are relative to the content of pyrite sulfur, heat and ash content of coal.展开更多
Dielectric properties offerrite ceramics have been less reported than their magnetic properties.Ourrecent study indicated that ferrite ceramics with very low dielectric loss tangent can be developed byusing appropriat...Dielectric properties offerrite ceramics have been less reported than their magnetic properties.Ourrecent study indicated that ferrite ceramics with very low dielectric loss tangent can be developed byusing appropriate sintering aids,together with the optimization of other sintering parameters suchas sintering temperature and time duration.Among various candidates of sintering aids,Bi_(2)O_(3)isthe most promising one.It is important to find that the optimized concentration of sintering aid forfull densification is not sufficient to achieve lowest dielectric loss tangent.This short review was aimed to summarize the understanding in microstructural evolution,grain growth,densificationand dielectric properties offerrite ceramics as a function of sintering aid concentration and sinteringparameters,which could be used as a guidance to develop ferrite ceramics with low dielectric losstangents for various applications.展开更多
基金Supported by Key Project of Chinese National Programs for Fundamental Research Development(973 Project 2005CB221502)
文摘In the light of fractal geometry theory, the characteristics of coal's electric parameters (including dielectric constant, alternating conductivity, dielectric loss angle tangent and electric polarization constant) were studied by using literature data. The results are shown that the electrical properties of coal have fractal characteristic. The fractal dimensions of dielectric, alternating conductivity, dielectric loss angle tangent were obtained, and are relative to the content of pyrite sulfur, heat and ash content of coal.
文摘Dielectric properties offerrite ceramics have been less reported than their magnetic properties.Ourrecent study indicated that ferrite ceramics with very low dielectric loss tangent can be developed byusing appropriate sintering aids,together with the optimization of other sintering parameters suchas sintering temperature and time duration.Among various candidates of sintering aids,Bi_(2)O_(3)isthe most promising one.It is important to find that the optimized concentration of sintering aid forfull densification is not sufficient to achieve lowest dielectric loss tangent.This short review was aimed to summarize the understanding in microstructural evolution,grain growth,densificationand dielectric properties offerrite ceramics as a function of sintering aid concentration and sinteringparameters,which could be used as a guidance to develop ferrite ceramics with low dielectric losstangents for various applications.
