The shortcomings of oil-immersed transformer solid insulation like low high-temperature resistance of the insulation paper and the uneven distribution of electric field caused by the large difference of dielectric con...The shortcomings of oil-immersed transformer solid insulation like low high-temperature resistance of the insulation paper and the uneven distribution of electric field caused by the large difference of dielectric constants between insulation paper and transformer oil,restricted the development of transformer with smaller size and larger capacity.In view of this situation and the transformer’s demand for the dielectric physicochemical and mechanical property of insulation material,polycarbonate,polyester film and polyphenylene sulfide with high high-temperature resistance were chosen for the comparison analysis in this paper We did the 300-day thermal aging experiment on four samples in transformer oil under different aging temperatures of90°C,110°C and 130°C,then analyzed the changes of their dielectric properties.The experiment results are as follows;the permittivity and dielectric dissipation factor of the three polymer materials are apparently smaller than those of the paper both before and after 300-day aging;the volume resistivity and partial discharge inception voltage of the three materials are higher than those of the paper both before and after aging;and the breakdown field strength of polycarbonate is higher than that of the paper both before and after aging,while that of polyester film and polyphenylene sulfide are slightly lower than that of the paper.展开更多
The application of antimony sulfide(Sb_(2)S_(3))has been limited mainly to the energy storage and photoelectric conversion fields.However,in this work,the application of Sb_(2)S_(3) is extended to the field of electro...The application of antimony sulfide(Sb_(2)S_(3))has been limited mainly to the energy storage and photoelectric conversion fields.However,in this work,the application of Sb_(2)S_(3) is extended to the field of electromagnetic(EM)wave absorption for the first time.High-permittivity Sb_(2)S_(3) singlecrystal nanorods were prepared successfully and exhibited excellent performance,with a low reflection loss of -65.9 dB(13.0 GHz,3.8 mm)and an ultra-wide effective absorption bandwidth of 9.5 GHz(8.5-18.0 GHz,4.1 mm).After excluding the general absorption mechanisms,including conductive losses,interfacial polarization,and dipole polarization,the distinctive single-crystal volume polarization affected by shape anisotropy was proposed.This work not only meets the challenge of a single-component dielectric material design but also introduces a new concept for construction of efficient dielectric EM wave absorption material.展开更多
We reported the dielectric properties of CaCu3Ti4O12 in the temperature range from room temperature to 800℃ and the frequency range from 20 Hz to 10 MHz.Apart from the widely reported dielectric anomaly occurring aro...We reported the dielectric properties of CaCu3Ti4O12 in the temperature range from room temperature to 800℃ and the frequency range from 20 Hz to 10 MHz.Apart from the widely reported dielectric anomaly occurring around 200℃,three additional dielectric anomalies were found.The new anomalies are very sensitive to electrode sintering conditions and annealing atmospheres,indicating that they are dependent not only on the electrode-sample contact but also on oxygen vacancies.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.50977025)
文摘The shortcomings of oil-immersed transformer solid insulation like low high-temperature resistance of the insulation paper and the uneven distribution of electric field caused by the large difference of dielectric constants between insulation paper and transformer oil,restricted the development of transformer with smaller size and larger capacity.In view of this situation and the transformer’s demand for the dielectric physicochemical and mechanical property of insulation material,polycarbonate,polyester film and polyphenylene sulfide with high high-temperature resistance were chosen for the comparison analysis in this paper We did the 300-day thermal aging experiment on four samples in transformer oil under different aging temperatures of90°C,110°C and 130°C,then analyzed the changes of their dielectric properties.The experiment results are as follows;the permittivity and dielectric dissipation factor of the three polymer materials are apparently smaller than those of the paper both before and after 300-day aging;the volume resistivity and partial discharge inception voltage of the three materials are higher than those of the paper both before and after aging;and the breakdown field strength of polycarbonate is higher than that of the paper both before and after aging,while that of polyester film and polyphenylene sulfide are slightly lower than that of the paper.
基金supported by the National Natural Science Foundation of China(51572157,21902085,and 51702188)the Natural Science Foundation of Shandong Province(ZR2019QF012)+1 种基金the Fundamental Research Funds for the Central Universities(2018JC046)Young Scholars Program of Shandong University(2018WLJH25)。
文摘The application of antimony sulfide(Sb_(2)S_(3))has been limited mainly to the energy storage and photoelectric conversion fields.However,in this work,the application of Sb_(2)S_(3) is extended to the field of electromagnetic(EM)wave absorption for the first time.High-permittivity Sb_(2)S_(3) singlecrystal nanorods were prepared successfully and exhibited excellent performance,with a low reflection loss of -65.9 dB(13.0 GHz,3.8 mm)and an ultra-wide effective absorption bandwidth of 9.5 GHz(8.5-18.0 GHz,4.1 mm).After excluding the general absorption mechanisms,including conductive losses,interfacial polarization,and dipole polarization,the distinctive single-crystal volume polarization affected by shape anisotropy was proposed.This work not only meets the challenge of a single-component dielectric material design but also introduces a new concept for construction of efficient dielectric EM wave absorption material.
基金supported by the National Natural Science Foundation of China(11074001)
文摘We reported the dielectric properties of CaCu3Ti4O12 in the temperature range from room temperature to 800℃ and the frequency range from 20 Hz to 10 MHz.Apart from the widely reported dielectric anomaly occurring around 200℃,three additional dielectric anomalies were found.The new anomalies are very sensitive to electrode sintering conditions and annealing atmospheres,indicating that they are dependent not only on the electrode-sample contact but also on oxygen vacancies.
