在导弹类金属-介质复合目标电磁散射特性求解过程中,采用常规迭代求解方法存在难以收敛以及内迭代边界积分区域重复求解的问题。针对该问题,在传统有限元边界积分区域分解法(finite element boundary integral domain decomposition met...在导弹类金属-介质复合目标电磁散射特性求解过程中,采用常规迭代求解方法存在难以收敛以及内迭代边界积分区域重复求解的问题。针对该问题,在传统有限元边界积分区域分解法(finite element boundary integral domain decomposition method,FE-BI-DDM)的基础上,采用了更为灵活的多区多求解器的方法(multi domain multi solver method,MDMSM)。该方法对导弹类金属-介质复合目标中难以收敛的金属区域,使用快速直接求逆的方法求解,由于可以使用独立的网格模型进行电磁建模,避免了内迭代部分的模型重复建立过程,从而大幅减少了整体模型求解时间。实验结果表明:所提方法可以在相同计算精度的条件下,以不过多增加内存空间为前提,大幅缩短了导弹类目标的金属-介质复合模型的电磁求解时间。该方法为开展导弹类目标特性分析提供了一条可行的技术途径。展开更多
Direct demodulation method(DDM) was applied to reconstruct γ-ray spectra. Boosted Richardson-Lucy iteration was introduced into DDM. Monte Carlo method(here GEANT 4) was proposed to calibrate response function and es...Direct demodulation method(DDM) was applied to reconstruct γ-ray spectra. Boosted Richardson-Lucy iteration was introduced into DDM. Monte Carlo method(here GEANT 4) was proposed to calibrate response function and establish response matrix. First, gauss function was regarded as total energy peak. Spectra line was simulated with nine gauss functions. And afterwards DDM was applied to reconstruct the simulated spectra line and determine peak positions and areas. Compared with original spectra, for case that peak position interval was about 1/3 full width half maximum(FWHM), the error of rebuilding peak position was 2 channels. The rest of peaks could be searched accurately. The relative errors of all peaks' area were less than 4%. Then, three key factors, including noise, background, response matrix, were discussed. Finally, DDM was applied to calibrate the field NaI gamma spectrometer. The errors of U, Th, K were less than 5%. Comprehensive studies have shown that it is feasible to reconstruct gamma-ray spectra with DDM. DDM can significantly pseudo-improve energy resolution of gamma spectrometer, effectively decompose doublets whose peak potential interval is1/3 FHWM, and accurately search peak and calculate areas. DDM can restrain noise strongly but is greatly influenced by background. And DDM can improve the accuracy of qualitative and quantitative analysis in combination with the conventional spectrum analysis method.展开更多
文摘在导弹类金属-介质复合目标电磁散射特性求解过程中,采用常规迭代求解方法存在难以收敛以及内迭代边界积分区域重复求解的问题。针对该问题,在传统有限元边界积分区域分解法(finite element boundary integral domain decomposition method,FE-BI-DDM)的基础上,采用了更为灵活的多区多求解器的方法(multi domain multi solver method,MDMSM)。该方法对导弹类金属-介质复合目标中难以收敛的金属区域,使用快速直接求逆的方法求解,由于可以使用独立的网格模型进行电磁建模,避免了内迭代部分的模型重复建立过程,从而大幅减少了整体模型求解时间。实验结果表明:所提方法可以在相同计算精度的条件下,以不过多增加内存空间为前提,大幅缩短了导弹类目标的金属-介质复合模型的电磁求解时间。该方法为开展导弹类目标特性分析提供了一条可行的技术途径。
基金Supported by National Science Foundation for Distinguished Young Scholars(No.41025015)Natural Science Foundation of China(No.41274130)+1 种基金Sichuan Youth Science and Technology Innovation Team(No.2011JTD0013)Sichuan Province Science and Technology Support Plan(No.2013FZ0022)
文摘Direct demodulation method(DDM) was applied to reconstruct γ-ray spectra. Boosted Richardson-Lucy iteration was introduced into DDM. Monte Carlo method(here GEANT 4) was proposed to calibrate response function and establish response matrix. First, gauss function was regarded as total energy peak. Spectra line was simulated with nine gauss functions. And afterwards DDM was applied to reconstruct the simulated spectra line and determine peak positions and areas. Compared with original spectra, for case that peak position interval was about 1/3 full width half maximum(FWHM), the error of rebuilding peak position was 2 channels. The rest of peaks could be searched accurately. The relative errors of all peaks' area were less than 4%. Then, three key factors, including noise, background, response matrix, were discussed. Finally, DDM was applied to calibrate the field NaI gamma spectrometer. The errors of U, Th, K were less than 5%. Comprehensive studies have shown that it is feasible to reconstruct gamma-ray spectra with DDM. DDM can significantly pseudo-improve energy resolution of gamma spectrometer, effectively decompose doublets whose peak potential interval is1/3 FHWM, and accurately search peak and calculate areas. DDM can restrain noise strongly but is greatly influenced by background. And DDM can improve the accuracy of qualitative and quantitative analysis in combination with the conventional spectrum analysis method.
