The GaAs material is a major semiconductor material,and it has high electron transfer rate and direct transition energy band structure.The devices and integrated circuits fabricated on the GaAs substrates have a lot o...The GaAs material is a major semiconductor material,and it has high electron transfer rate and direct transition energy band structure.The devices and integrated circuits fabricated on the GaAs substrates have a lot of advantages such as high speed information processing.Small perturbations in the manufacturing of GaAs materials can lead to defects.The defects in the GaAs materials can degrade the performance of materials.A new method is presented in this paper for detecting the micro-defects in GaAs materials by using time resolved emissions.In this method,the micro-defects in GaAs materials are detected by making use of the photon emission features of microdefects.The strength of the emitted photons from the micro-defects is increased by applying the electric current or the periodic pulse signals to GaAs materials.The singlephoton detector is used to detect the photon emissions of the micro-defects.The time resolved photon emissions and single-photon detection are used to record and compare the amounts of the emitted photons that come from the given regions of the normal GaAs materials and the defective GaAs materials.A lot of experimental results show that the micro-defects in the GaAs materials can be detected by using the method proposed in this paper.展开更多
This study aims to explore a method suitable for welding 7A52 high-strength aluminum alloy plates with continuously varying thicknesses and the causes of microscopic defects in welds in order to improve welding qualit...This study aims to explore a method suitable for welding 7A52 high-strength aluminum alloy plates with continuously varying thicknesses and the causes of microscopic defects in welds in order to improve welding quality.Comparative tests were conducted to analyze weld defects and deformation when welding the aluminum alloy plates with varying thicknesses at constant laser power.The laser power required for melting welds at varying-thickness positions was estimated.Weld defects and deformation when welding aluminum alloy plates with varying thicknesses at con-tinuous variable laser power were detected.The causes of microscopic weld defects during constant-power welding were analyzed.The welding defects and deformation and the welding quality were improved by welding aluminum alloy plates at continuous variable power.展开更多
基金supported by the National Natural Science Foundation of China (61072028)the Project of Department of Education of Guangdong Province (2012KJCX0040)Guangdong Province and Chinese Ministry of Education Cooperation Project of Industry,Education and Academy (2009B090300339)
文摘The GaAs material is a major semiconductor material,and it has high electron transfer rate and direct transition energy band structure.The devices and integrated circuits fabricated on the GaAs substrates have a lot of advantages such as high speed information processing.Small perturbations in the manufacturing of GaAs materials can lead to defects.The defects in the GaAs materials can degrade the performance of materials.A new method is presented in this paper for detecting the micro-defects in GaAs materials by using time resolved emissions.In this method,the micro-defects in GaAs materials are detected by making use of the photon emission features of microdefects.The strength of the emitted photons from the micro-defects is increased by applying the electric current or the periodic pulse signals to GaAs materials.The singlephoton detector is used to detect the photon emissions of the micro-defects.The time resolved photon emissions and single-photon detection are used to record and compare the amounts of the emitted photons that come from the given regions of the normal GaAs materials and the defective GaAs materials.A lot of experimental results show that the micro-defects in the GaAs materials can be detected by using the method proposed in this paper.
基金supported by the Guangxi College Youth Project Foundation(No.2023KY0913)Technology Project of Guizhou Province,Guizhou Science and Technology Cooper-ation Support Project Foundation[2020](No.2Y055)。
文摘This study aims to explore a method suitable for welding 7A52 high-strength aluminum alloy plates with continuously varying thicknesses and the causes of microscopic defects in welds in order to improve welding quality.Comparative tests were conducted to analyze weld defects and deformation when welding the aluminum alloy plates with varying thicknesses at constant laser power.The laser power required for melting welds at varying-thickness positions was estimated.Weld defects and deformation when welding aluminum alloy plates with varying thicknesses at con-tinuous variable laser power were detected.The causes of microscopic weld defects during constant-power welding were analyzed.The welding defects and deformation and the welding quality were improved by welding aluminum alloy plates at continuous variable power.
