screw-cone-like Zn_(2)GeO_(4)-ZnO particles with a base diameter of approximately 400 nm and a height of 400–800 nm or so were successfully synthesised by combustion oxidation of zinc and germanium powder at 960℃.No...screw-cone-like Zn_(2)GeO_(4)-ZnO particles with a base diameter of approximately 400 nm and a height of 400–800 nm or so were successfully synthesised by combustion oxidation of zinc and germanium powder at 960℃.No catalyst or carrier gases were used.XRD and SEM analyses reveal that Zn_(2)GeO_(4) and ZnO grew to parasitic crystals evenly in interaction with each other.EDS images exhibit the homogeneity of the distribution of Ge and Zn.The formation mechanism is discussed and attributed to the unique growth process of the screw-cone-like Zn_(2)GeO_(4)-ZnO particles and its vapour-solid(VS)growth mechanism.In addition,the Zn_(2)GeO_(4)-ZnO particles could tune the energy level structure of nano-tetrapod ZnO,which leads to the emission peak redshift from 376 nm to 435 nm and enhances the light emission intensity in the visible light region.展开更多
The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at hig...The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at high temperature,which is dependent on the temperature by data-mining.The result shows that the permittivity and loss tangent obtained by data-mining are well consistent with the measured ones.The high-temperature permittivity can be well predicted for SiO2/SiO2 by the as-proposed model and the data-mining method.展开更多
We synthesize composite systems of multi-wall carbon nanotubes(MWCNTs)/SiO_(2) by using the sol−gel method.The dielectric properties of the systems with different-concentration MWCNTs are studied.In our MWCNTs/SiO_(2)...We synthesize composite systems of multi-wall carbon nanotubes(MWCNTs)/SiO_(2) by using the sol−gel method.The dielectric properties of the systems with different-concentration MWCNTs are studied.In our MWCNTs/SiO_(2) inorganic systems,the twin−percolation phenomenon exists when the concentrations of MWCNTs are 5–10%and 15–20%.The permittivity and conductivity have jumping changes.The twin−percolation phenomenon is attributed to the special transfer mechanism of MWCNTs in the system,determined by hopping and migrating electrons.Variations of dielectric properties and conductance of the MWCNTs/SiO_(2) systems are conformed to the percolation theory.The special percolation phenomenon and electric properties of MWCNTs/SiO_(2) can help us comprehend the conductivity mechanism of the MWCNTs/SiO2 systems effectively,and promote the development of a high performance function composite system.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 50872159,50972014 , 51272110.
文摘screw-cone-like Zn_(2)GeO_(4)-ZnO particles with a base diameter of approximately 400 nm and a height of 400–800 nm or so were successfully synthesised by combustion oxidation of zinc and germanium powder at 960℃.No catalyst or carrier gases were used.XRD and SEM analyses reveal that Zn_(2)GeO_(4) and ZnO grew to parasitic crystals evenly in interaction with each other.EDS images exhibit the homogeneity of the distribution of Ge and Zn.The formation mechanism is discussed and attributed to the unique growth process of the screw-cone-like Zn_(2)GeO_(4)-ZnO particles and its vapour-solid(VS)growth mechanism.In addition,the Zn_(2)GeO_(4)-ZnO particles could tune the energy level structure of nano-tetrapod ZnO,which leads to the emission peak redshift from 376 nm to 435 nm and enhances the light emission intensity in the visible light region.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50872159,50972014,51072024 and 51132002.
文摘The high-temperature permittivity of quartz fibre-reinforced silicon dioxide (SiO2/SiO2 ) nano-composites is studied on the basis of the multi-scale theoretical model.We obtain the permittivity of the SiO2/SiO2 at high temperature,which is dependent on the temperature by data-mining.The result shows that the permittivity and loss tangent obtained by data-mining are well consistent with the measured ones.The high-temperature permittivity can be well predicted for SiO2/SiO2 by the as-proposed model and the data-mining method.
基金Supported by the National Natural Science Foundation of China under Grant Nos.50872159,50972014 and 51072024.
文摘We synthesize composite systems of multi-wall carbon nanotubes(MWCNTs)/SiO_(2) by using the sol−gel method.The dielectric properties of the systems with different-concentration MWCNTs are studied.In our MWCNTs/SiO_(2) inorganic systems,the twin−percolation phenomenon exists when the concentrations of MWCNTs are 5–10%and 15–20%.The permittivity and conductivity have jumping changes.The twin−percolation phenomenon is attributed to the special transfer mechanism of MWCNTs in the system,determined by hopping and migrating electrons.Variations of dielectric properties and conductance of the MWCNTs/SiO_(2) systems are conformed to the percolation theory.The special percolation phenomenon and electric properties of MWCNTs/SiO_(2) can help us comprehend the conductivity mechanism of the MWCNTs/SiO2 systems effectively,and promote the development of a high performance function composite system.
