The fusion excitation functions for 12 colliding systems with 96≤Z_(1)Z_(2)≤608 are analyzed using coupled-channel(CC)calculations based on the M3Y double-folding(DF)potential supplemented with a repulsive potential...The fusion excitation functions for 12 colliding systems with 96≤Z_(1)Z_(2)≤608 are analyzed using coupled-channel(CC)calculations based on the M3Y double-folding(DF)potential supplemented with a repulsive potential that takes into account the incompressibility of the nuclear matter.We also applied the polarization effects of hot nuclear matter(PEHNM)on the calculations of the bare nucleus-nucleus interaction potential within the framework of the modified density-dependent Seyler-Blanchard(SB)approach in the T^(2)approximation.Our results reveal that we obtain a nice description of the experimental data of different fusion systems when we use the present theoretical approach to calculate the energy-dependent values of the fusion cross sections.In this paper,the influence of the PEHNM on the surface diffuseness parameter of the Woods-Saxon(WS)potential is also studied.In order to reach this goal,we extract the corresponding values of this parameter based on the modified form of the DF potential(M3Y+Repulsion+polarization).We find that the extracted values are located in a range between a=0.61 and 0.80 fm at different incident energies.It seems that the polarization effects of hot nuclear matter play a key role in describing the abnormally large values of the nuclear potential diffusenesses in the heavy-ion fusion reactions.Additionally,the regular decreasing trend for the diffuseness parameter of the nucleus-nucleus potential with the increase in the bombarding energies is also observed.展开更多
The main purpose of this work is to study doping level effects on a silicon PV cell under both moderate light concentration and normal illumination. This study also aims to compare the doping level effects under the b...The main purpose of this work is to study doping level effects on a silicon PV cell under both moderate light concentration and normal illumination. This study also aims to compare the doping level effects under the both illumination modes. The results show for both illumination modes that diffusion parameters decrease with increasing doping level. These results are in agreement with the studies of the current and the voltage which showed for the two illumination modes that doping level increase leads to a decrease in current density and an increase in voltage. It also emerges for the two illumination modes and for the doping range 10<sup>13</sup> cm<sup>-3</sup> - 10<sup>16</sup> cm<sup>-3</sup>, a decrease of maximum power and conversion efficiency. The results also show that decrease of diffusion parameters is faster under moderate concentration in comparison with normal illumination. These results predict a greater variation rate of the current, the voltage, the maximum power and the conversion efficiency under moderate concentration compared to normal illumination. Contrary to diffusion parameters study, the results show higher variation rates of parameters under normal illumination. This is explained by the fact that under moderate concentration, carriers density is close to doping level: the cell is then in high injection condition. Consequently, under moderate concentration, carriers density is less sensitive to doping level variations. The study confirms that carriers density variation with the doping level is weak under the moderate concentration compared to normal illumination.展开更多
Corner stall predictions are important and difficult in axial compressors.However,all of the prediction models have proved to be ineffective for advanced compressor blades,which tend to use the combined sweep and dihe...Corner stall predictions are important and difficult in axial compressors.However,all of the prediction models have proved to be ineffective for advanced compressor blades,which tend to use the combined sweep and dihedral.As for the prediction parameter DL,although it effectively modeled the effects of the adverse pressure gradient and secondary flow,it failed to predict the corner stall of curved blades because the model failed to consider the intersection of the boundary layer at the corner region.In this paper,the shape factor gradientψof the boundary layer at the corner region was investigated by numerically studying specially shaped expansion pipes under different adverse pressure gradients.The improved prediction parameter DJ was presented based on the model of ψ and the circumferential pressure gradient ζ.A comparison of the critical range of the prediction parameters DL and DJ was investigated using the NACA65 cascade database,which was established by a numerical method.Then,the stall criterion was validated according to the experimental results of various test facilities with different blade geometries and experimental conditions.The results show that the improved prediction parameter is able to predict the corner separation/stall flows and is in good agreement with the experimental results for axial compressors with three-dimensional designed blades.展开更多
Proeutectoid ferrite with carbon content xo precipitating from austenite in a multicomponent steel at temperature T is supposed to be equivalent to proeutectoid ferrite with the same carbon content precipitating from...Proeutectoid ferrite with carbon content xo precipitating from austenite in a multicomponent steel at temperature T is supposed to be equivalent to proeutectoid ferrite with the same carbon content precipitating from austenite in Fe-C binary system at temperature T'.is described as the temperature difference of proeutectiod ferrite formation, and can be calculated from the Fe-X diagrams and the equilibrium temperature A3. By introducing Tf and basing on the thermodynamic model for Fe-C binary alloy, the driving force for phase transformation from austenite to proeutectoid ferrite in multicomponent steels has been successfully calculated. Through the Johnson-Mehl equation and using the data hem known TTT diagrams, the relationship between the chemical composition and the intedecial edenly packeter as well as activation energy for proeutectoid ferrite formation can be calculated. The starting curves of proeutectoid ferritic transformation calculated in this way in some hypo-proeutectoid structural steels agree well with the erperimental data.展开更多
Parameter estimation plays a critical role for the application and development of S-shaped growth model in the agricultural sciences and others.In this paper,a modified particle swarm optimization algorithm based on t...Parameter estimation plays a critical role for the application and development of S-shaped growth model in the agricultural sciences and others.In this paper,a modified particle swarm optimization algorithm based on the diffusion phenomenon（DPPSO） was employed to estimate the parameters for this model.Under the sense of least squares,the parameter estimation problem of S-shaped growth model,taking the Gompertz and Logistic models for example,is transformed into a multi-dimensional function optimization problem.The results show that the DPPSO algorithm can effectively estimate the parameters of the S-shaped growth model.展开更多
In this paper the meteorological background for the formation of plume from the forest fire in Northeast China on 7—8 May 1987 is stated.The long-range instantaneous diffusion parameters are calculated by using the s...In this paper the meteorological background for the formation of plume from the forest fire in Northeast China on 7—8 May 1987 is stated.The long-range instantaneous diffusion parameters are calculated by using the satellite photograph of the plumes with visible length ranging from 100 to over 500 kin.The results of cal- culation show that the relations between instantaneous diffusion parameter and travel time(up to 60000 sec.) obey the law of linear or 3/2 power.In addition,heat release from the fire on May 7—8 estimated by puff rising formula can meet,in respect to the order of magnitude,the value gained on the field survey.展开更多
The angular distributions of fission fragments for the 32S+184W reaction near Coulomb barrier energies are measured.The ex perimental fission excitation function is obtained.The measured fission cross sections are dec...The angular distributions of fission fragments for the 32S+184W reaction near Coulomb barrier energies are measured.The ex perimental fission excitation function is obtained.The measured fission cross sections are decomposed into fusion-fission,quasi-fission and fast fission contributions by the dinuclear system(DNS)model.The hindrance to completing fusion both at small and large collision energies is explained.The fusion excitation functions of 32S+90,96Zr in an energy range from above to below the Coulomb barrier are measured and analyzed within a semi-classical model.The obvious effect of positive Q-value multi-neutron transfers on the sub-barrier fusion enhancement is observed in the 32S+96Zr system.In addition,the excitation functions of quasi-elastic scattering at a backward angle have been measured with high precision for the systems of 16O+208Pb,196Pt,184W,and 154,152Sm at energies well below the Coulomb barrier.Considering the deformed coupling effects,the extracted diffuseness parameters are close to the values extracted from the systematic analysis of elastic and inelastic scattering data.The elastic scattering angular distribution of 17F+12C at 60 MeV is measured and calculated by using the continuum-discretized coupled-channels(CDCC)approach.It is found that the diffuseness parameter of the real part of core-target potential has to be increased by 20%to reproduce the experimental result,which corresponds to an increment of potential depth at the surface re gion.The breakup cross section and the coupling between breakup and elastic scattering are small.展开更多
文摘The fusion excitation functions for 12 colliding systems with 96≤Z_(1)Z_(2)≤608 are analyzed using coupled-channel(CC)calculations based on the M3Y double-folding(DF)potential supplemented with a repulsive potential that takes into account the incompressibility of the nuclear matter.We also applied the polarization effects of hot nuclear matter(PEHNM)on the calculations of the bare nucleus-nucleus interaction potential within the framework of the modified density-dependent Seyler-Blanchard(SB)approach in the T^(2)approximation.Our results reveal that we obtain a nice description of the experimental data of different fusion systems when we use the present theoretical approach to calculate the energy-dependent values of the fusion cross sections.In this paper,the influence of the PEHNM on the surface diffuseness parameter of the Woods-Saxon(WS)potential is also studied.In order to reach this goal,we extract the corresponding values of this parameter based on the modified form of the DF potential(M3Y+Repulsion+polarization).We find that the extracted values are located in a range between a=0.61 and 0.80 fm at different incident energies.It seems that the polarization effects of hot nuclear matter play a key role in describing the abnormally large values of the nuclear potential diffusenesses in the heavy-ion fusion reactions.Additionally,the regular decreasing trend for the diffuseness parameter of the nucleus-nucleus potential with the increase in the bombarding energies is also observed.
文摘The main purpose of this work is to study doping level effects on a silicon PV cell under both moderate light concentration and normal illumination. This study also aims to compare the doping level effects under the both illumination modes. The results show for both illumination modes that diffusion parameters decrease with increasing doping level. These results are in agreement with the studies of the current and the voltage which showed for the two illumination modes that doping level increase leads to a decrease in current density and an increase in voltage. It also emerges for the two illumination modes and for the doping range 10<sup>13</sup> cm<sup>-3</sup> - 10<sup>16</sup> cm<sup>-3</sup>, a decrease of maximum power and conversion efficiency. The results also show that decrease of diffusion parameters is faster under moderate concentration in comparison with normal illumination. These results predict a greater variation rate of the current, the voltage, the maximum power and the conversion efficiency under moderate concentration compared to normal illumination. Contrary to diffusion parameters study, the results show higher variation rates of parameters under normal illumination. This is explained by the fact that under moderate concentration, carriers density is close to doping level: the cell is then in high injection condition. Consequently, under moderate concentration, carriers density is less sensitive to doping level variations. The study confirms that carriers density variation with the doping level is weak under the moderate concentration compared to normal illumination.
基金supported by the National Natural Science Foundation of China (No. 51676015)
文摘Corner stall predictions are important and difficult in axial compressors.However,all of the prediction models have proved to be ineffective for advanced compressor blades,which tend to use the combined sweep and dihedral.As for the prediction parameter DL,although it effectively modeled the effects of the adverse pressure gradient and secondary flow,it failed to predict the corner stall of curved blades because the model failed to consider the intersection of the boundary layer at the corner region.In this paper,the shape factor gradientψof the boundary layer at the corner region was investigated by numerically studying specially shaped expansion pipes under different adverse pressure gradients.The improved prediction parameter DJ was presented based on the model of ψ and the circumferential pressure gradient ζ.A comparison of the critical range of the prediction parameters DL and DJ was investigated using the NACA65 cascade database,which was established by a numerical method.Then,the stall criterion was validated according to the experimental results of various test facilities with different blade geometries and experimental conditions.The results show that the improved prediction parameter is able to predict the corner separation/stall flows and is in good agreement with the experimental results for axial compressors with three-dimensional designed blades.
文摘Proeutectoid ferrite with carbon content xo precipitating from austenite in a multicomponent steel at temperature T is supposed to be equivalent to proeutectoid ferrite with the same carbon content precipitating from austenite in Fe-C binary system at temperature T'.is described as the temperature difference of proeutectiod ferrite formation, and can be calculated from the Fe-X diagrams and the equilibrium temperature A3. By introducing Tf and basing on the thermodynamic model for Fe-C binary alloy, the driving force for phase transformation from austenite to proeutectoid ferrite in multicomponent steels has been successfully calculated. Through the Johnson-Mehl equation and using the data hem known TTT diagrams, the relationship between the chemical composition and the intedecial edenly packeter as well as activation energy for proeutectoid ferrite formation can be calculated. The starting curves of proeutectoid ferritic transformation calculated in this way in some hypo-proeutectoid structural steels agree well with the erperimental data.
基金Supported by the National Natural Science Foundation of China (61070009)the National Science and Technology Support Plan (2012BAH25F02)+2 种基金the Project of Jingdezhen Science and Technology Bureau (2011-1-47)the National Natural Science Foundation of Jiangxi Province (2009GZS0065)the Youth Science Foundation of Jiangxi Provincial Department of Education (GJJ12514)
文摘Parameter estimation plays a critical role for the application and development of S-shaped growth model in the agricultural sciences and others.In this paper,a modified particle swarm optimization algorithm based on the diffusion phenomenon（DPPSO） was employed to estimate the parameters for this model.Under the sense of least squares,the parameter estimation problem of S-shaped growth model,taking the Gompertz and Logistic models for example,is transformed into a multi-dimensional function optimization problem.The results show that the DPPSO algorithm can effectively estimate the parameters of the S-shaped growth model.
文摘In this paper the meteorological background for the formation of plume from the forest fire in Northeast China on 7—8 May 1987 is stated.The long-range instantaneous diffusion parameters are calculated by using the satellite photograph of the plumes with visible length ranging from 100 to over 500 kin.The results of cal- culation show that the relations between instantaneous diffusion parameter and travel time(up to 60000 sec.) obey the law of linear or 3/2 power.In addition,heat release from the fire on May 7—8 estimated by puff rising formula can meet,in respect to the order of magnitude,the value gained on the field survey.
基金supported by the National Natural Science Foundation of China(Grant Nos.10575134,10675169 and 10735100)the Major State Basic Research Developing Program(Grant No.2007CB815003)
文摘The angular distributions of fission fragments for the 32S+184W reaction near Coulomb barrier energies are measured.The ex perimental fission excitation function is obtained.The measured fission cross sections are decomposed into fusion-fission,quasi-fission and fast fission contributions by the dinuclear system(DNS)model.The hindrance to completing fusion both at small and large collision energies is explained.The fusion excitation functions of 32S+90,96Zr in an energy range from above to below the Coulomb barrier are measured and analyzed within a semi-classical model.The obvious effect of positive Q-value multi-neutron transfers on the sub-barrier fusion enhancement is observed in the 32S+96Zr system.In addition,the excitation functions of quasi-elastic scattering at a backward angle have been measured with high precision for the systems of 16O+208Pb,196Pt,184W,and 154,152Sm at energies well below the Coulomb barrier.Considering the deformed coupling effects,the extracted diffuseness parameters are close to the values extracted from the systematic analysis of elastic and inelastic scattering data.The elastic scattering angular distribution of 17F+12C at 60 MeV is measured and calculated by using the continuum-discretized coupled-channels(CDCC)approach.It is found that the diffuseness parameter of the real part of core-target potential has to be increased by 20%to reproduce the experimental result,which corresponds to an increment of potential depth at the surface re gion.The breakup cross section and the coupling between breakup and elastic scattering are small.
