A two-dimensional(2D)organic-inorganic hybrid perovskite(OIHP)material is considered as a promising candidate for a long-term stable photodetector owing to its outstanding phase and environmental stability.Herein,we d...A two-dimensional(2D)organic-inorganic hybrid perovskite(OIHP)material is considered as a promising candidate for a long-term stable photodetector owing to its outstanding phase and environmental stability.Herein,we demonstrate a perovskite photodiode based on the DJ phase 2D perovskite(PDA)(MA)_(n-1)Pb_(n)I_(3n+1)(where PDA is 1,3-propylenediamine,MA is methylamine,nominal n=4).The best-performance device exhibits a high detectivity of 4.57×10^(11) Jones,a responsivity of 0.25 A·W^(-1) at 480 nm,a low dark current density of 9.60×10^(-4) mA cm^(-2),and a remarkable on/off ratio of 3.10×10^(5).The unencapsulated device can maintain 95%of the initial photocurrent density after 90 days under an ambient atmosphere with relative humidity(RH)of 65%,demonstrating its improved stability than the 3D counterpart.The excellent stability of the photodiode based on 2D perovskite promises its bright commercial application ftiture.展开更多
A two-step fringing field dielectrophoretic assembly method for carbon nanotube thin film transistors （CNT-TFTs） fabrication was demonstrated. Densely aligned CNT arrays were assembled at the source and drain electr...A two-step fringing field dielectrophoretic assembly method for carbon nanotube thin film transistors （CNT-TFTs） fabrication was demonstrated. Densely aligned CNT arrays were assembled at the source and drain electrodes sequentially which form a cascade structure of the aligned CNT arrays. The cascade structure reduces the possibility of percolating metallic pathways in the channel, which is beneficial to device performance. In this way, both high on/off current ratio Ion/loft （up to 107） and high out-put current density （8.5μA/μm） were obtained in short channel length （1-2.5μm） CNT-TFTs. The reported CNT assem- bling strategy is site selective and highly efficient, which can be scaled up to large size substrates and leads to high throughput of CNT-TFTs fabrication.展开更多
In order to study component matching which exists in off-design situation at the initial design stage of turbine engine,by establishing performance analysis model of low bypass ratio mixed flow turbofan engine and com...In order to study component matching which exists in off-design situation at the initial design stage of turbine engine,by establishing performance analysis model of low bypass ratio mixed flow turbofan engine and components characteristic data,and by applying Newton-Raphson method to solve the nonlinear equations of offdesign points in flying envelop,the factors which affect matching between engine components are studied.The results show that low pressure turbine(LPT)must not operate in a critical condition,and the partial derivative(slope)of pressure ratio to similitude mass flow ratio of working point in LPT characteristic map affects the stability of engine.The smaller the slope is,the more stable the engine is.In addition,the engine is more stable when the fan characteristic map is steep.展开更多
基金Supported by the National Natural Science Foundation of China(No.U1605241)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR116)the Natural Science Foundation of Fujian Province for Distinguished Young Scholars(No.2019J06023)。
文摘A two-dimensional(2D)organic-inorganic hybrid perovskite(OIHP)material is considered as a promising candidate for a long-term stable photodetector owing to its outstanding phase and environmental stability.Herein,we demonstrate a perovskite photodiode based on the DJ phase 2D perovskite(PDA)(MA)_(n-1)Pb_(n)I_(3n+1)(where PDA is 1,3-propylenediamine,MA is methylamine,nominal n=4).The best-performance device exhibits a high detectivity of 4.57×10^(11) Jones,a responsivity of 0.25 A·W^(-1) at 480 nm,a low dark current density of 9.60×10^(-4) mA cm^(-2),and a remarkable on/off ratio of 3.10×10^(5).The unencapsulated device can maintain 95%of the initial photocurrent density after 90 days under an ambient atmosphere with relative humidity(RH)of 65%,demonstrating its improved stability than the 3D counterpart.The excellent stability of the photodiode based on 2D perovskite promises its bright commercial application ftiture.
文摘A two-step fringing field dielectrophoretic assembly method for carbon nanotube thin film transistors （CNT-TFTs） fabrication was demonstrated. Densely aligned CNT arrays were assembled at the source and drain electrodes sequentially which form a cascade structure of the aligned CNT arrays. The cascade structure reduces the possibility of percolating metallic pathways in the channel, which is beneficial to device performance. In this way, both high on/off current ratio Ion/loft （up to 107） and high out-put current density （8.5μA/μm） were obtained in short channel length （1-2.5μm） CNT-TFTs. The reported CNT assem- bling strategy is site selective and highly efficient, which can be scaled up to large size substrates and leads to high throughput of CNT-TFTs fabrication.
基金supported in part by the Fundamental Research Funds for the Central Universities(No.NZ2016103)
文摘In order to study component matching which exists in off-design situation at the initial design stage of turbine engine,by establishing performance analysis model of low bypass ratio mixed flow turbofan engine and components characteristic data,and by applying Newton-Raphson method to solve the nonlinear equations of offdesign points in flying envelop,the factors which affect matching between engine components are studied.The results show that low pressure turbine(LPT)must not operate in a critical condition,and the partial derivative(slope)of pressure ratio to similitude mass flow ratio of working point in LPT characteristic map affects the stability of engine.The smaller the slope is,the more stable the engine is.In addition,the engine is more stable when the fan characteristic map is steep.
