94Zr的中子谱因子可用于研究93Zr(n,γ)94Zr直接辐射俘获反应的激发函数和天体物理反应率,对研究s-过程的核合成有重要意义。现有的94Zr中子谱因子实验结果仍存在较大的差异。本工作在北京HI-13串列加速器Q3D磁谱仪上测量了12C+94Zr、13...94Zr的中子谱因子可用于研究93Zr(n,γ)94Zr直接辐射俘获反应的激发函数和天体物理反应率,对研究s-过程的核合成有重要意义。现有的94Zr中子谱因子实验结果仍存在较大的差异。本工作在北京HI-13串列加速器Q3D磁谱仪上测量了12C+94Zr、13C+94Zr弹性散射反应及94Zr(12C,13C)93Zr单中子转移反应的角分布。通过对弹性散射角分布的仔细分析,拟合出了入射道和出射道的光学势参数,并结合扭曲波玻恩近似(Distorted wave Born approximation,DWBA)理论对转移反应的微分截面进行了理论分析,提取出94Zr的中子谱因子为2.60±0.20。展开更多
A modified distorted-wave Born approximation （DWBA） method is used to calculate the triple differential cross sections （TDCSs） in a coplanar asymmetric geometry for the electron impact single ionization of a He （...A modified distorted-wave Born approximation （DWBA） method is used to calculate the triple differential cross sections （TDCSs） in a coplanar asymmetric geometry for the electron impact single ionization of a He （ls2） atom at intermediate and lower energies. The post-collision interaction and the polarization effect in （e, 2e） collisions of helium are considered in the calculations. The polarization potentials from the damping method and density functional theory （DFT） are compared. Theoretical results are compared with the recent experimental data.展开更多
The excitation function and angular distributions for the ^16O+^20Ne system have been explained using the distorted wave Born approximation (DWBA) calculations. The real and imaginary Woods Saxon optical potentials ar...The excitation function and angular distributions for the ^16O+^20Ne system have been explained using the distorted wave Born approximation (DWBA) calculations. The real and imaginary Woods Saxon optical potentials are assumed to be energy-dependent. The gross resonant structures observed in the ^20Ne(^16O,^16O)^20 Ne excitation function are well described by the present DWBA calculations. Although the elastic and elastic-transfer analyses introduce a qualitative description of the experimental data, the coherent sum of the two reaction processes exhibit a much better result for both forward and large-angle data.展开更多
Angular distributions have been measured for the elastic and inelastic scattering and one-nucle-on transfer of 88.0 MeV <sup>16</sup>O on <sup>116</sup>Sn.Coupled-channels calculations have bee...Angular distributions have been measured for the elastic and inelastic scattering and one-nucle-on transfer of 88.0 MeV <sup>16</sup>O on <sup>116</sup>Sn.Coupled-channels calculations have been performed for the elasticand inelastic scattering,and DWBA treatment for one-proton stripping(<sup>16</sup>O,<sup>15</sup>N),and one-neutron pick-up(<sup>16</sup>O,<sup>17</sup>O)reactions.Tne results compared with the previous 64 MeV ones show energy dependence inthe optical potentials and also in the normalization factors with the spectroscopic factors preserving consis-tent in DWBA analysis,which might relate to the threshold anomaly phenomena.展开更多
A method for calculating multistep direct reactions for both continuum anddiscrete levels is proposed.The energy-angle correction scattering kernel is adopted forcontinuum and discrete levels in the semiclassical appr...A method for calculating multistep direct reactions for both continuum anddiscrete levels is proposed.The energy-angle correction scattering kernel is adopted forcontinuum and discrete levels in the semiclassical approach,in which the angular mo-mentum and parity conservations are considered.The Legendre coefficients of the angu-lar distributions are calculated based on one-step distorted wave Born approximation instead of nucleon-nucleon scattering expressions in nuclear matter.The calculateddiscrete level neutron angular distributions of <sup>11</sup>B（p,n<sub>0</sub>）<sup>11</sup>C reaction and the cross sec-tions of<sup>11</sup>B（p,n<sub>0</sub>）<sup>11</sup>C and <sup>11</sup>B（p,n）<sup>11</sup>C reactions reproduce the experimental data reason-ably.This approach can also be used for composite particle emissions.展开更多
The microscopic DWBA was used to calculate the inelastic neutron scattering on <sup>11</sup>B to 2.14MeV excited state and some energy dependent parameters were used to improve the calculation.The inte-gra...The microscopic DWBA was used to calculate the inelastic neutron scattering on <sup>11</sup>B to 2.14MeV excited state and some energy dependent parameters were used to improve the calculation.The inte-grated inelastic cross sections and the angular distributions of the <sup>11</sup>B（n,n′）<sup>11</sup>B*（2.14 MeV excitedstate）were given for the incident neutrons whose energy varies from 7.54 MeV to 20.0 MeV.Resultswere also given for the experimental blank data.展开更多
The microscopic DWBA was used to calculate the inelastic neutron scatteringon <sup>12</sup>C to 4.44 MeV excited state and some energy dependent parameters were used toimprove the calculation.The inelastic...The microscopic DWBA was used to calculate the inelastic neutron scatteringon <sup>12</sup>C to 4.44 MeV excited state and some energy dependent parameters were used toimprove the calculation.The inelastic integrated cross sections and the angular distribu-tions of <sup>12</sup>C（n,n’）<sup>12</sup>C 4.44 MeV excited state were given for the incident neutron whoseenergy varies from 7.0 MeV to 20.0 MeV.Results were also given for the experimentalblank data.展开更多
The differential cross sections of <sup>42</sup>Ca（p,α）<sup>39</sup>K with <sup>39</sup>K in （3/2）<sup>+</sup> and （1/2）<sup>+</sup> states at E<su...The differential cross sections of <sup>42</sup>Ca（p,α）<sup>39</sup>K with <sup>39</sup>K in （3/2）<sup>+</sup> and （1/2）<sup>+</sup> states at E<sub>p</sub>=20.0 MeV are measured and analyzed by using microscopic DWBA calculation.The realpotential is calculated via density dependent realistic nuclear force in a double-folding procedurewhereas the imaginary potential is expressed in terms of Fourier-Bessel functions.An improvedcalculation is obtained and analyzed to understand the absolute amplitude problem.展开更多
Hybrid wavelength-division-multiplexing(WDM)/time-division-multiplexing(TDM) ethernet passive optical networks(EPONs) can achieve low per-subscriber cost and scalability to increase the number of subscribers. This pap...Hybrid wavelength-division-multiplexing(WDM)/time-division-multiplexing(TDM) ethernet passive optical networks(EPONs) can achieve low per-subscriber cost and scalability to increase the number of subscribers. This paper discusses dynamic wavelength and bandwidth allocation(DWBA) algorithm in hybrid WDM/TDM EPONs.Based on the correlation structure of the variable bit rate(VBR) video traffic,we propose a quality-ofservice (QoS) supported DWBA using adaptive linear traffic prediction.Wavelength and timeslot are allocated dynamically by optical line terminal(OLT) to all optical network units(ONUs) based on the bandwidth requests and the guaranteed service level agreements(SLA) of all ONUs.Mean square error of the predicted average arriving rate of compound video traffic during waiting period is minimized through Wiener-Hopf equation.Simulation results show that the DWBA-adaptive-linear-prediction(DWBA-ALP) algorithm can significantly improve the QoS performances in terms of low delay and high bandwidth utilization.展开更多
文摘94Zr的中子谱因子可用于研究93Zr(n,γ)94Zr直接辐射俘获反应的激发函数和天体物理反应率,对研究s-过程的核合成有重要意义。现有的94Zr中子谱因子实验结果仍存在较大的差异。本工作在北京HI-13串列加速器Q3D磁谱仪上测量了12C+94Zr、13C+94Zr弹性散射反应及94Zr(12C,13C)93Zr单中子转移反应的角分布。通过对弹性散射角分布的仔细分析,拟合出了入射道和出射道的光学势参数,并结合扭曲波玻恩近似(Distorted wave Born approximation,DWBA)理论对转移反应的微分截面进行了理论分析,提取出94Zr的中子谱因子为2.60±0.20。
文摘A modified distorted-wave Born approximation （DWBA） method is used to calculate the triple differential cross sections （TDCSs） in a coplanar asymmetric geometry for the electron impact single ionization of a He （ls2） atom at intermediate and lower energies. The post-collision interaction and the polarization effect in （e, 2e） collisions of helium are considered in the calculations. The polarization potentials from the damping method and density functional theory （DFT） are compared. Theoretical results are compared with the recent experimental data.
文摘The excitation function and angular distributions for the ^16O+^20Ne system have been explained using the distorted wave Born approximation (DWBA) calculations. The real and imaginary Woods Saxon optical potentials are assumed to be energy-dependent. The gross resonant structures observed in the ^20Ne(^16O,^16O)^20 Ne excitation function are well described by the present DWBA calculations. Although the elastic and elastic-transfer analyses introduce a qualitative description of the experimental data, the coherent sum of the two reaction processes exhibit a much better result for both forward and large-angle data.
基金①The project supported by the Nuclear Science Foundation of China
文摘Angular distributions have been measured for the elastic and inelastic scattering and one-nucle-on transfer of 88.0 MeV <sup>16</sup>O on <sup>116</sup>Sn.Coupled-channels calculations have been performed for the elasticand inelastic scattering,and DWBA treatment for one-proton stripping(<sup>16</sup>O,<sup>15</sup>N),and one-neutron pick-up(<sup>16</sup>O,<sup>17</sup>O)reactions.Tne results compared with the previous 64 MeV ones show energy dependence inthe optical potentials and also in the normalization factors with the spectroscopic factors preserving consis-tent in DWBA analysis,which might relate to the threshold anomaly phenomena.
文摘A method for calculating multistep direct reactions for both continuum anddiscrete levels is proposed.The energy-angle correction scattering kernel is adopted forcontinuum and discrete levels in the semiclassical approach,in which the angular mo-mentum and parity conservations are considered.The Legendre coefficients of the angu-lar distributions are calculated based on one-step distorted wave Born approximation instead of nucleon-nucleon scattering expressions in nuclear matter.The calculateddiscrete level neutron angular distributions of <sup>11</sup>B（p,n<sub>0</sub>）<sup>11</sup>C reaction and the cross sec-tions of<sup>11</sup>B（p,n<sub>0</sub>）<sup>11</sup>C and <sup>11</sup>B（p,n）<sup>11</sup>C reactions reproduce the experimental data reason-ably.This approach can also be used for composite particle emissions.
文摘The microscopic DWBA was used to calculate the inelastic neutron scattering on <sup>11</sup>B to 2.14MeV excited state and some energy dependent parameters were used to improve the calculation.The inte-grated inelastic cross sections and the angular distributions of the <sup>11</sup>B（n,n′）<sup>11</sup>B*（2.14 MeV excitedstate）were given for the incident neutrons whose energy varies from 7.54 MeV to 20.0 MeV.Resultswere also given for the experimental blank data.
文摘The microscopic DWBA was used to calculate the inelastic neutron scatteringon <sup>12</sup>C to 4.44 MeV excited state and some energy dependent parameters were used toimprove the calculation.The inelastic integrated cross sections and the angular distribu-tions of <sup>12</sup>C（n,n’）<sup>12</sup>C 4.44 MeV excited state were given for the incident neutron whoseenergy varies from 7.0 MeV to 20.0 MeV.Results were also given for the experimentalblank data.
文摘The differential cross sections of <sup>42</sup>Ca（p,α）<sup>39</sup>K with <sup>39</sup>K in （3/2）<sup>+</sup> and （1/2）<sup>+</sup> states at E<sub>p</sub>=20.0 MeV are measured and analyzed by using microscopic DWBA calculation.The realpotential is calculated via density dependent realistic nuclear force in a double-folding procedurewhereas the imaginary potential is expressed in terms of Fourier-Bessel functions.An improvedcalculation is obtained and analyzed to understand the absolute amplitude problem.
文摘Hybrid wavelength-division-multiplexing(WDM)/time-division-multiplexing(TDM) ethernet passive optical networks(EPONs) can achieve low per-subscriber cost and scalability to increase the number of subscribers. This paper discusses dynamic wavelength and bandwidth allocation(DWBA) algorithm in hybrid WDM/TDM EPONs.Based on the correlation structure of the variable bit rate(VBR) video traffic,we propose a quality-ofservice (QoS) supported DWBA using adaptive linear traffic prediction.Wavelength and timeslot are allocated dynamically by optical line terminal(OLT) to all optical network units(ONUs) based on the bandwidth requests and the guaranteed service level agreements(SLA) of all ONUs.Mean square error of the predicted average arriving rate of compound video traffic during waiting period is minimized through Wiener-Hopf equation.Simulation results show that the DWBA-adaptive-linear-prediction(DWBA-ALP) algorithm can significantly improve the QoS performances in terms of low delay and high bandwidth utilization.
