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基于DDS技术的LFM信号产生与FPGA实现 被引量:6
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作者 谭德勇 陆聪 +1 位作者 杨维明 卫春芳 《计算机测量与控制》 2019年第11期275-279,共5页
在分析线性调频(LFM)信号的时频特性和基于直接数字频率合成器(DDS)技术信号产生原理的基础上,选择ALTERA公司的Cyclone II系列的FPGA芯片EP2C70F896C6FPGA,采用ROM查找表技术,利用QuartusII系统提供的PLL锁相环IP核设计系统时钟,设计... 在分析线性调频(LFM)信号的时频特性和基于直接数字频率合成器(DDS)技术信号产生原理的基础上,选择ALTERA公司的Cyclone II系列的FPGA芯片EP2C70F896C6FPGA,采用ROM查找表技术,利用QuartusII系统提供的PLL锁相环IP核设计系统时钟,设计产生带宽B=10 MHz、时宽T=2.5μs的LFM信号;通过调用Modelsim仿真工具进行RTL仿真验证,FPGA电路仿真的结果与MATLAB仿真结果相符。 展开更多
关键词 DDS技术 LFM信号 FPGA实现
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IL-1β regulates the mouse Fas ligand expression in corneal endothelial cells
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作者 ZHANG Jie Yang Ke +2 位作者 tan deyong ZENG JunYing Alan FINE 《Chinese Science Bulletin》 SCIE EI CAS 2007年第16期2210-2215,共6页
Constitutively expressed Fas ligand (FasL) in several distinct epithelial cell types appears to protect tissues by inducing apoptosis of Fas+ immune cells during inflammatory reactions. To study the rela-tionship of F... Constitutively expressed Fas ligand (FasL) in several distinct epithelial cell types appears to protect tissues by inducing apoptosis of Fas+ immune cells during inflammatory reactions. To study the rela-tionship of FasL and inflammation process in cornea,we examined the effects of inflammatory cytokine IL-1β on the FasL production,expression and cytotoxic function in corneal endothelial cells. In this paper,we demonstrate that IL-1β inhibits the FasL production and expression in corneal endothelial cells. The promoter activities of FasL in these cells are reduced by IL-1β in a dose-dependent manner. Finally,we also find that IL-1β block the cytotoxic effects of FasL derived from corneal endothelial cells to the Fas+ target cells. These data support the view that FasL derived from corneal endothelial cells modulate inflammation within cornea. 展开更多
关键词 FAS配体 角膜内皮细胞 基因表达 IL-1Β 大鼠 动物实验
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