In vitro experimental set-up is an important tool for investigating abdominal aortic aneurysm (AAA). Accurate reproduction of the physiological pulsatile flow waveform in the abdominal aorta at various anatomic locati...In vitro experimental set-up is an important tool for investigating abdominal aortic aneurysm (AAA). Accurate reproduction of the physiological pulsatile flow waveform in the abdominal aorta at various anatomic locations is an important component of these experimental methods. The objective of this study is to establish an experimental set-up to generate a physiological pulsatile flow for in vitro simulations of the abdominal aorta. The physiological flow was established by a computer-controlled peristaltic pump and the flow field in a circular straight pipe is measured under pulsatile flow conditions by a 2-dimensional particle image velocimetry system (2D-PIV). Experimental results show that the in vitro experimental set-up provides a flow with a period of 2 s, a reasonable cross-sectional velocity distribution and an approximate inlet velocity profile that is close to the human abdominal aorta.展开更多
设计并开发了一种DSP（digital signal processor）控制的全桥移相零电压DC—DC变换器实验装置。该实验装置以全桥DC—DC变换器为基础，采用移相PWM（pulse width modulation）控制技术，以DSP为控制器，实现各主功率管的零电压开关。...设计并开发了一种DSP（digital signal processor）控制的全桥移相零电压DC—DC变换器实验装置。该实验装置以全桥DC—DC变换器为基础，采用移相PWM（pulse width modulation）控制技术，以DSP为控制器，实现各主功率管的零电压开关。分析了变换器的工作原理及系统设计方案。该实验装置具有技术先进、设计合理、安全可靠、操作简便等优点。在实验教学中学生反映良好，收到了较好的教学效果。展开更多
文摘In vitro experimental set-up is an important tool for investigating abdominal aortic aneurysm (AAA). Accurate reproduction of the physiological pulsatile flow waveform in the abdominal aorta at various anatomic locations is an important component of these experimental methods. The objective of this study is to establish an experimental set-up to generate a physiological pulsatile flow for in vitro simulations of the abdominal aorta. The physiological flow was established by a computer-controlled peristaltic pump and the flow field in a circular straight pipe is measured under pulsatile flow conditions by a 2-dimensional particle image velocimetry system (2D-PIV). Experimental results show that the in vitro experimental set-up provides a flow with a period of 2 s, a reasonable cross-sectional velocity distribution and an approximate inlet velocity profile that is close to the human abdominal aorta.
文摘设计并开发了一种DSP（digital signal processor）控制的全桥移相零电压DC—DC变换器实验装置。该实验装置以全桥DC—DC变换器为基础，采用移相PWM（pulse width modulation）控制技术，以DSP为控制器，实现各主功率管的零电压开关。分析了变换器的工作原理及系统设计方案。该实验装置具有技术先进、设计合理、安全可靠、操作简便等优点。在实验教学中学生反映良好，收到了较好的教学效果。
