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大型天线近场测量的研究
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作者 秦顺友 毛乃宏 林海 《无线电通信技术》 北大核心 1990年第2期10-13,共4页
本文运用了Jacobi-Bessel级数展开法对近场测量数据进行处理,推算出天线的远场方向图,给出了计算步骤和测量概要,最后,用1.5米反射面天线作为模拟天线,获得其近场数据,由此推出天线的远场方向图,并且和实测结果进行了比较.在确定大的和... 本文运用了Jacobi-Bessel级数展开法对近场测量数据进行处理,推算出天线的远场方向图,给出了计算步骤和测量概要,最后,用1.5米反射面天线作为模拟天线,获得其近场数据,由此推出天线的远场方向图,并且和实测结果进行了比较.在确定大的和对地球引力敏感的空间天线远场方向图时,讨论了极平面构形在机械和电性能上的独特优点. 展开更多
关键词 天线 航空天线 近声测量
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Asymptotic Formulas for Thermography Based Recovery of Anomalies
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作者 Habib Ammari Anastasia Kozhemyak Darko Volkov 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2009年第1期18-42,共25页
We start from a realistic half space then use to develop a mathematical asymptotic model for thermal imaging, which we analysis well suited for the design of reconstruction algorithms. We seek to reconstruct thermal a... We start from a realistic half space then use to develop a mathematical asymptotic model for thermal imaging, which we analysis well suited for the design of reconstruction algorithms. We seek to reconstruct thermal anomalies only through their rough features. With this way our proposed algorithms are stable against measurement noise and geometry perturbations. Based on rigorous asymptotic estimates, we first obtain an approximation for the temperature profile which we then use to design noniterative detection algorithms. We show on numerical simulations evidence that they are accurate and robust. Moreover, we provide a mathematical model for ultrasonic temperature imaging, which is an important technique in cancerous tissue ablation therapy. 展开更多
关键词 THERMOGRAPHY imaging asymptotic formulas small anomalies direct imaging algorithms half-space problem.
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