为了应对车载毫米波雷达大斜视成像困难的问题,本文提出一种改进的极坐标格式算法(Polar Format Algorithm,PFA)对条带车载毫米波雷达斜视回波进行基于子孔径拼接的成像。该算法从条带数据与聚束数据的特点出发,将全孔径回波划分为子孔...为了应对车载毫米波雷达大斜视成像困难的问题,本文提出一种改进的极坐标格式算法(Polar Format Algorithm,PFA)对条带车载毫米波雷达斜视回波进行基于子孔径拼接的成像。该算法从条带数据与聚束数据的特点出发,将全孔径回波划分为子孔径,利用PFA处理子孔径数据。由于PFA存在波前弯曲误差,子图像不能直接拼接,因此对每一幅子图像进行几何失真校正。同时,以重叠子孔径的划分方式保证成像结果的高分辨率。最后截取子图像进行拼接得到条带SAR成像结果。所提方法解决了车载毫米波雷达大斜视情况下两维耦合严重的问题。通过对点目标和实测数据的仿真与分析验证了所提方法的有效性。展开更多
This research provides a comprehensive analysis of the health impacts of Per- and Polyfluoroalkyl Substances (PFAS) through an integration of epidemiological and toxicological studies. The study identifies significant...This research provides a comprehensive analysis of the health impacts of Per- and Polyfluoroalkyl Substances (PFAS) through an integration of epidemiological and toxicological studies. The study identifies significant correlations between PFAS exposure and adverse health outcomes, including thyroid dysfunction, elevated cholesterol levels, and increased risk of specific cancers. Utilizing a mixed-methods approach, the research combines a systematic review and meta-analysis of recent literature with in vitro and in vivo toxicological experiments. The epidemiological analysis reveals increased risks of thyroid dysfunction, cholesterol elevation, and certain cancers among PFAS-exposed individuals. Toxicological findings further corroborate these results, showing dose-dependent cytotoxic effects in human cell lines and endocrine disruption in rodent models. The study emphasizes the importance of regulatory measures to mitigate PFAS exposure and the urgent need for more comprehensive research into their long-term effects. The integration of epidemiological and toxicological data underscores the significant health risks posed by PFAS, highlighting the necessity of immediate action to limit exposure and develop safer alternatives.展开更多
文摘为了应对车载毫米波雷达大斜视成像困难的问题,本文提出一种改进的极坐标格式算法(Polar Format Algorithm,PFA)对条带车载毫米波雷达斜视回波进行基于子孔径拼接的成像。该算法从条带数据与聚束数据的特点出发,将全孔径回波划分为子孔径,利用PFA处理子孔径数据。由于PFA存在波前弯曲误差,子图像不能直接拼接,因此对每一幅子图像进行几何失真校正。同时,以重叠子孔径的划分方式保证成像结果的高分辨率。最后截取子图像进行拼接得到条带SAR成像结果。所提方法解决了车载毫米波雷达大斜视情况下两维耦合严重的问题。通过对点目标和实测数据的仿真与分析验证了所提方法的有效性。
文摘This research provides a comprehensive analysis of the health impacts of Per- and Polyfluoroalkyl Substances (PFAS) through an integration of epidemiological and toxicological studies. The study identifies significant correlations between PFAS exposure and adverse health outcomes, including thyroid dysfunction, elevated cholesterol levels, and increased risk of specific cancers. Utilizing a mixed-methods approach, the research combines a systematic review and meta-analysis of recent literature with in vitro and in vivo toxicological experiments. The epidemiological analysis reveals increased risks of thyroid dysfunction, cholesterol elevation, and certain cancers among PFAS-exposed individuals. Toxicological findings further corroborate these results, showing dose-dependent cytotoxic effects in human cell lines and endocrine disruption in rodent models. The study emphasizes the importance of regulatory measures to mitigate PFAS exposure and the urgent need for more comprehensive research into their long-term effects. The integration of epidemiological and toxicological data underscores the significant health risks posed by PFAS, highlighting the necessity of immediate action to limit exposure and develop safer alternatives.
