Analysis of the elastic scattering of protons from 12C nuclei had been performed within the framework of both the optical model and single folding model at different proton energies;17, 30.3, 40, 49.48 and 61.4 MeV. W...Analysis of the elastic scattering of protons from 12C nuclei had been performed within the framework of both the optical model and single folding model at different proton energies;17, 30.3, 40, 49.48 and 61.4 MeV. We have obtained the global potential parameters which could fairly reproduce the experimental data for p+12C elastic scattering at the aforementioned energies. The radial and energy dependence of the real and imaginary parts of the potential were calculated. Good agreement between experimental data and theoretical predictions in the whole angular range was obtained using both phenomenological approach (Optical Model), and semi-microscopic approach (Single Folding). In single folding calculations, the real part of the potential was calculated from a more fundamental basis by the folding method in which the NN interaction VNN(r), is folded into the density of the target nuclei and supplemented with a phenomenological imaginary potential. The obtained normalization factor Nr is in the range of 0.75 - 0.9.展开更多
Recently measured thermal conductivity in single-walled carbon nanotube ropes in the temperature range 8 - 350 K has been explained using an anisotropic dynamical model which not only takes into account the quasi two-...Recently measured thermal conductivity in single-walled carbon nanotube ropes in the temperature range 8 - 350 K has been explained using an anisotropic dynamical model which not only takes into account the quasi two-dimensional nature of the folded graphene sheets that forms the nanotubes, but also the intertube coupling, in addition to the phonon frequency and dimensionality dependent relaxation time of phonon-phonon scattering and interaction.展开更多
In this Let ter,a single scattering turbulence model in a narrow beam case for ultraviolet(UV)communication is proposed based on the division of the effective scattering volume.This model takes the variation of atmosp...In this Let ter,a single scattering turbulence model in a narrow beam case for ultraviolet(UV)communication is proposed based on the division of the effective scattering volume.This model takes the variation of atmospheric scattering,absorption,and turbulence in different paths into account.Meanwhile,the applicable transceiver configurations of this model are provided by analyzing path loss error caused by the single scattering assumption in the UV channel.Furthermore,we investigate the effect of turbulence on the probability density function of the arriving power in both coplanar and non-coplanar scenarios.The averaging effect of multipath propagation on the arriving power's fluctuations is presented.Then,the bit-error-rate performance is also studied.This work provides an efficient way for UV turbulence channel estimation.展开更多
Due to the presence of turbid media, such as microdust and water vapor in the environment, outdoor pictures taken under hazy weather circumstances are typically degraded. To enhance the quality of such images, this wo...Due to the presence of turbid media, such as microdust and water vapor in the environment, outdoor pictures taken under hazy weather circumstances are typically degraded. To enhance the quality of such images, this work proposes a new hybrid λ2-λ0 penalty model for image dehazing. This model performs a weighted fusion of two distinct transmission maps, generated by imposing λ2 and λ0 norm penalties on the approximate regression coefficients of the transmission map. This approach effectively balances the sparsity and smoothness associated with the λ0 and λ2 norms, thereby optimizing the transmittance map. Specifically, when the λ2 norm is penalized in the model, an updated guided image is obtained after implementing λ0 penalty. The resulting optimization problem is effectively solved using the least square method and the alternating direction algorithm. The dehazing framework combines the advantages of λ2 and λ0 norms, enhancing sparse and smoothness, resulting in higher quality images with clearer details and preserved edges.展开更多
We proposed a method to estimate single scattering albedo of winter wheat over the North China Plain with AMSR-E passive microwave imagery. The relationships of single scattering albedo and optical depth between 6. 92...We proposed a method to estimate single scattering albedo of winter wheat over the North China Plain with AMSR-E passive microwave imagery. The relationships of single scattering albedo and optical depth between 6. 925 GHz and 10. 65 GHz were derived from simulations. To retrieve the single scattering albedo,the relationships were combined with the physical expressions of microwave vegetation indices derived from the first-order parameterized emission model. Comparisons with normalized difference vegetation index( NDVI) obtained from daily MODIS reflectance product showed that the variations in winter wheat single scattering albedo were similar to those of winter wheat NDVI. However,several differences were observed. NDVI showed saturation from the heading stage to the milky stage of winter wheat,whereas single scattering albedo remained sensitive to the growth of winter wheat. Single scattering albedo offers certain advantages in reflecting the growth status of winter wheat.展开更多
A physical model of ke V electron scattering in multi-layer medium and a Monte Carlo simulation method proposed by the authors have been successfully applied to theoretical calculation on the emission of backscattered...A physical model of ke V electron scattering in multi-layer medium and a Monte Carlo simulation method proposed by the authors have been successfully applied to theoretical calculation on the emission of backscattered electron, X-ray quantitative analysis in multi-layer films and the energy deposition of electron beam exposure.The model is based on the 'equal number of steps and variational step length' con-cept. In the model, when an electron comes from one medium into another, the scattering number of the electron in the 'new' medium is considered as N-n,展开更多
文摘Analysis of the elastic scattering of protons from 12C nuclei had been performed within the framework of both the optical model and single folding model at different proton energies;17, 30.3, 40, 49.48 and 61.4 MeV. We have obtained the global potential parameters which could fairly reproduce the experimental data for p+12C elastic scattering at the aforementioned energies. The radial and energy dependence of the real and imaginary parts of the potential were calculated. Good agreement between experimental data and theoretical predictions in the whole angular range was obtained using both phenomenological approach (Optical Model), and semi-microscopic approach (Single Folding). In single folding calculations, the real part of the potential was calculated from a more fundamental basis by the folding method in which the NN interaction VNN(r), is folded into the density of the target nuclei and supplemented with a phenomenological imaginary potential. The obtained normalization factor Nr is in the range of 0.75 - 0.9.
文摘Recently measured thermal conductivity in single-walled carbon nanotube ropes in the temperature range 8 - 350 K has been explained using an anisotropic dynamical model which not only takes into account the quasi two-dimensional nature of the folded graphene sheets that forms the nanotubes, but also the intertube coupling, in addition to the phonon frequency and dimensionality dependent relaxation time of phonon-phonon scattering and interaction.
基金the Basic Research Program of Shenzhen(No.JCYJ20170412171744267)。
文摘In this Let ter,a single scattering turbulence model in a narrow beam case for ultraviolet(UV)communication is proposed based on the division of the effective scattering volume.This model takes the variation of atmospheric scattering,absorption,and turbulence in different paths into account.Meanwhile,the applicable transceiver configurations of this model are provided by analyzing path loss error caused by the single scattering assumption in the UV channel.Furthermore,we investigate the effect of turbulence on the probability density function of the arriving power in both coplanar and non-coplanar scenarios.The averaging effect of multipath propagation on the arriving power's fluctuations is presented.Then,the bit-error-rate performance is also studied.This work provides an efficient way for UV turbulence channel estimation.
文摘Due to the presence of turbid media, such as microdust and water vapor in the environment, outdoor pictures taken under hazy weather circumstances are typically degraded. To enhance the quality of such images, this work proposes a new hybrid λ2-λ0 penalty model for image dehazing. This model performs a weighted fusion of two distinct transmission maps, generated by imposing λ2 and λ0 norm penalties on the approximate regression coefficients of the transmission map. This approach effectively balances the sparsity and smoothness associated with the λ0 and λ2 norms, thereby optimizing the transmittance map. Specifically, when the λ2 norm is penalized in the model, an updated guided image is obtained after implementing λ0 penalty. The resulting optimization problem is effectively solved using the least square method and the alternating direction algorithm. The dehazing framework combines the advantages of λ2 and λ0 norms, enhancing sparse and smoothness, resulting in higher quality images with clearer details and preserved edges.
基金National Natural Science Foundation of China(No.41171259)National Basic Research Program of China(973 Program)(No.2013CB733406)
文摘We proposed a method to estimate single scattering albedo of winter wheat over the North China Plain with AMSR-E passive microwave imagery. The relationships of single scattering albedo and optical depth between 6. 925 GHz and 10. 65 GHz were derived from simulations. To retrieve the single scattering albedo,the relationships were combined with the physical expressions of microwave vegetation indices derived from the first-order parameterized emission model. Comparisons with normalized difference vegetation index( NDVI) obtained from daily MODIS reflectance product showed that the variations in winter wheat single scattering albedo were similar to those of winter wheat NDVI. However,several differences were observed. NDVI showed saturation from the heading stage to the milky stage of winter wheat,whereas single scattering albedo remained sensitive to the growth of winter wheat. Single scattering albedo offers certain advantages in reflecting the growth status of winter wheat.
基金Project supported by the National Natural Science Foundation of China
文摘A physical model of ke V electron scattering in multi-layer medium and a Monte Carlo simulation method proposed by the authors have been successfully applied to theoretical calculation on the emission of backscattered electron, X-ray quantitative analysis in multi-layer films and the energy deposition of electron beam exposure.The model is based on the 'equal number of steps and variational step length' con-cept. In the model, when an electron comes from one medium into another, the scattering number of the electron in the 'new' medium is considered as N-n,
