We present an accurate spectral integral method(SIM)for the analyses of scattering from multiple circular perfect electric conductor(PEC)cylinders.It solves the coupled surface integral equations by using the Fourier ...We present an accurate spectral integral method(SIM)for the analyses of scattering from multiple circular perfect electric conductor(PEC)cylinders.It solves the coupled surface integral equations by using the Fourier series and addition theorem to decouple the system.The SIM has exponential convergence so that the error decreases exponentially with the sample density on the surfaces,and requires only about 2–3 points per wavelength(PPW)to reach engineering accuracy defined as higher than 99%accuracy(or with an error smaller than 1%).Numerical results demonstrate that the SIM is much more accurate and efficient than the method of moments(MoM),and thus can be potentially used as the exact radiation boundary condition in the finite element and spectral element methods.展开更多
In order to study how to reliably perform quantitative tritium and helium analyses in thin film samples using enhanced proton backscattering （EPBS）, several EPBS spectra for some samples consisting of non-RBS light ...In order to study how to reliably perform quantitative tritium and helium analyses in thin film samples using enhanced proton backscattering （EPBS）, several EPBS spectra for some samples consisting of non-RBS light elements （i.e., T, 4He, 12C, 16O, natsi）, medium and heavy elements have been measured and analyzed using analytical SIMNRA and Monte Carlo-based CORTEO codes. The non-RBS cross sections needed in the CORTEO code are taken from the ENDF/B-Ⅶ database and the calculations of SigmaCalc code and are incorporated into the CORTEO code. All non-RBS cross section data over the entire proton incident energy-scattering angle plane are obtained by interpolation. It is quantitatively observed that in EPBS analysis the multiple and plural scattering effects have little impact on the energy spectra for light elements and the RBS cross sections of light elements can be used in the SIMNRA code for dual scattering calculations. It is also observed that the results given by the CORTEO code are higher than the results of the SIMNRA code in the low energy part of EPBS spectra, and are in better agreement with the experimental data. Tritium and helium analyses in thin film samples using EPBS can be performed reliably when the multiple and plural scattering contributions are completely accounted.展开更多
The mixture of water cloud droplets with black carbon impurities is modeled by external and internal mixing models.The internal mixing model is modeled with a two-layered sphere（water cloud droplets containing black ...The mixture of water cloud droplets with black carbon impurities is modeled by external and internal mixing models.The internal mixing model is modeled with a two-layered sphere（water cloud droplets containing black carbon（BC） inclusions）,and the single scattering and absorption characteristics are calculated at the visible wavelength of 0.55 μm by using the Lorenz-Mie theory.The external mixing model is developed assuming that the same amount of BC particles are mixed with the water droplets externally.The multiple scattering characteristics are computed by using the Monte Carlo method.The results show that when the size of the BC aerosol is small,the reflection intensity of the internal mixing model is bigger than that of the external mixing model.However,if the size of the BC aerosol is big,the absorption of the internal mixing model will be larger than that of the external mixing model.展开更多
文摘We present an accurate spectral integral method(SIM)for the analyses of scattering from multiple circular perfect electric conductor(PEC)cylinders.It solves the coupled surface integral equations by using the Fourier series and addition theorem to decouple the system.The SIM has exponential convergence so that the error decreases exponentially with the sample density on the surfaces,and requires only about 2–3 points per wavelength(PPW)to reach engineering accuracy defined as higher than 99%accuracy(or with an error smaller than 1%).Numerical results demonstrate that the SIM is much more accurate and efficient than the method of moments(MoM),and thus can be potentially used as the exact radiation boundary condition in the finite element and spectral element methods.
基金Supported by Chinese National Fusion Project for ITER(2009GB106004)National Natural Science Foundation of China(11175123)China Academy of Engineering Physics
文摘In order to study how to reliably perform quantitative tritium and helium analyses in thin film samples using enhanced proton backscattering （EPBS）, several EPBS spectra for some samples consisting of non-RBS light elements （i.e., T, 4He, 12C, 16O, natsi）, medium and heavy elements have been measured and analyzed using analytical SIMNRA and Monte Carlo-based CORTEO codes. The non-RBS cross sections needed in the CORTEO code are taken from the ENDF/B-Ⅶ database and the calculations of SigmaCalc code and are incorporated into the CORTEO code. All non-RBS cross section data over the entire proton incident energy-scattering angle plane are obtained by interpolation. It is quantitatively observed that in EPBS analysis the multiple and plural scattering effects have little impact on the energy spectra for light elements and the RBS cross sections of light elements can be used in the SIMNRA code for dual scattering calculations. It is also observed that the results given by the CORTEO code are higher than the results of the SIMNRA code in the low energy part of EPBS spectra, and are in better agreement with the experimental data. Tritium and helium analyses in thin film samples using EPBS can be performed reliably when the multiple and plural scattering contributions are completely accounted.
基金Project supported by the Natural Science Foundation of Shandong Province,China (Grant No. ZR2009AQ013)
文摘The mixture of water cloud droplets with black carbon impurities is modeled by external and internal mixing models.The internal mixing model is modeled with a two-layered sphere（water cloud droplets containing black carbon（BC） inclusions）,and the single scattering and absorption characteristics are calculated at the visible wavelength of 0.55 μm by using the Lorenz-Mie theory.The external mixing model is developed assuming that the same amount of BC particles are mixed with the water droplets externally.The multiple scattering characteristics are computed by using the Monte Carlo method.The results show that when the size of the BC aerosol is small,the reflection intensity of the internal mixing model is bigger than that of the external mixing model.However,if the size of the BC aerosol is big,the absorption of the internal mixing model will be larger than that of the external mixing model.
