Imidazoles are widely used as curing agents and accelerators for fabricating crosslinked epoxy materials applied in electrical and electronic fields.However,the intrinsic chemical structure of imidazole derivatives wo...Imidazoles are widely used as curing agents and accelerators for fabricating crosslinked epoxy materials applied in electrical and electronic fields.However,the intrinsic chemical structure of imidazole derivatives would greatly influence the polymerisation process,and further change the electrical properties,which was not emphasised.To achieve an in-depth understanding,commonly used imidazole only containing pyridine-type nitrogen and imidazole with both pyridine and pyrrole-type nitrogen were selected in this study.Electrical properties including dielectric properties,volume resistivity,breakdown strength,and especially energy storage performances were systematically investigated.We figured out that higher breakdown strength,glass transition temperature,and lower dielectric loss can be achieved with imidazole containing pyrrole-type nitrogen.Structure-induced curing mechanism diversity and the generated differences in polymer network were highlighted.With the capability to incorporate into the polymer network,the dielectric constant/loss of epoxy cured by imidazole containing pyrrole-type nitrogen is less sensitive with variation in concentration and a high breakdown strength of 577.9 MV/m was achieved.On the contrary,conspicuous decrease in the breakdown strength and increase in dielectric loss of the epoxy cured by imidazole only containing pyridine-type nitrogen were observed,especially at high concentration.Moreover,we also found that the epoxy can be fabricated into films with an attractive energy storage density/efficiency of 1.1 J/cm^(3)/97%@200 MV/m,which is twice of the commercial dielectric polypropylene film under the same electric field.展开更多
High electron mobility transistors(HEMT) have the potential to be used as high-sensitivity and realtime biosensors. HEMT biosensors have great market prospects. For the application of HEMT biosensors, the electric pro...High electron mobility transistors(HEMT) have the potential to be used as high-sensitivity and realtime biosensors. HEMT biosensors have great market prospects. For the application of HEMT biosensors, the electric properties consistency of the inter-chip performance have an important influence on the stability and repeatability of the detection. In this research, we fabricated GaAs/AlGaAs HEMT biosensors of different epitaxial structures and device structures to study the electric properties consistency. We study the relationship between channel size and consistency. We investigated the distribution of device current with location on 2 inch GaAs wafer. Based on the studies, the optimal device of a GaAs HEMT biosensor is an A-type epitaxial structure, and a U-type device structure, L = 40μm, W= 200 μm.展开更多
基金Young Talent Recruiting Plans of Xi'an Jiaotong University,Grant/Award Number:DQ6J015State Key Laboratory of Electrical Insulation and Power Equipment,Grant/Award Numbers:NO.EIPE21202,NO.EIPE21205,No.EIPE21315。
文摘Imidazoles are widely used as curing agents and accelerators for fabricating crosslinked epoxy materials applied in electrical and electronic fields.However,the intrinsic chemical structure of imidazole derivatives would greatly influence the polymerisation process,and further change the electrical properties,which was not emphasised.To achieve an in-depth understanding,commonly used imidazole only containing pyridine-type nitrogen and imidazole with both pyridine and pyrrole-type nitrogen were selected in this study.Electrical properties including dielectric properties,volume resistivity,breakdown strength,and especially energy storage performances were systematically investigated.We figured out that higher breakdown strength,glass transition temperature,and lower dielectric loss can be achieved with imidazole containing pyrrole-type nitrogen.Structure-induced curing mechanism diversity and the generated differences in polymer network were highlighted.With the capability to incorporate into the polymer network,the dielectric constant/loss of epoxy cured by imidazole containing pyrrole-type nitrogen is less sensitive with variation in concentration and a high breakdown strength of 577.9 MV/m was achieved.On the contrary,conspicuous decrease in the breakdown strength and increase in dielectric loss of the epoxy cured by imidazole only containing pyridine-type nitrogen were observed,especially at high concentration.Moreover,we also found that the epoxy can be fabricated into films with an attractive energy storage density/efficiency of 1.1 J/cm^(3)/97%@200 MV/m,which is twice of the commercial dielectric polypropylene film under the same electric field.
基金Project supported by the National Key Research and Development Program of China(No.2017YFB0405400)the Open Research Fund Program of the State Key Laboratory of Virology of China(No.2017IOV002)+1 种基金the National Natural Science Foundation of China(Nos.61274049,61404130,61574140)the Shenzhen Science and Technology Innovation Commission(No.JSGG20160608100922614)
文摘High electron mobility transistors(HEMT) have the potential to be used as high-sensitivity and realtime biosensors. HEMT biosensors have great market prospects. For the application of HEMT biosensors, the electric properties consistency of the inter-chip performance have an important influence on the stability and repeatability of the detection. In this research, we fabricated GaAs/AlGaAs HEMT biosensors of different epitaxial structures and device structures to study the electric properties consistency. We study the relationship between channel size and consistency. We investigated the distribution of device current with location on 2 inch GaAs wafer. Based on the studies, the optimal device of a GaAs HEMT biosensor is an A-type epitaxial structure, and a U-type device structure, L = 40μm, W= 200 μm.
