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高次谐波辐射发射特性研究

物理学报 2008年第7期57卷 4091-4098页

作者：葛愉成北京大学技术物理系和核物理与核技术国家重点实验室北京100871

报告由不同脉冲宽度(半高宽,FWHM)和不同载波-包络相位(CEP,Φ)的激光产生的高次谐波辐射能量输出时间特性即发射特性的研究结果.计算表明,由宽度为几个周期的激光产生的高次谐波辐射的截止能量明显低于由无限长脉冲宽度激光产生的截止... 详细信息

报告由不同脉冲宽度(半高宽,FWHM)和不同载波-包络相位(CEP,Φ)的激光产生的高次谐波辐射能量输出时间特性即发射特性的研究结果.计算表明,由宽度为几个周期的激光产生的高次谐波辐射的截止能量明显低于由无限长脉冲宽度激光产生的截止能量ωmax=3.17Up+Ip(其中ωmax为光子角频率,Up和Ip分别为激光有质动力势和原子的电离能).例如,由两周期(FWHM),Φ=15°的激光产生的高次谐波辐射的截止能量为ωmax=2.90Up+Ip,此时发射特性单脉冲(即分布单脉冲)具有最大的能量带宽0.86Up.脉冲中心位置的载波相位和时间宽度分别为0.94rad(弧度)和1.29rad.而该激光脉冲在Φ=-75°时能产生截止能量为ωmax=2.70Up+Ip,最大能量带宽为0.70Up的双分布脉冲,其中心位置分别为-0.58rad和2.43rad,宽度分别为1.22rad和1.33rad.随着激光脉冲宽度的增加,分布单脉冲的能量带宽比时间宽度下降得更快.对于一定宽度的激光脉冲,所产生的分布单脉冲的能量带宽和时间宽度的CEP依赖性显示出180°的周期结构.利用这个有趣的特点,在实验上可以通过调节CEP来选择分布脉冲的能量参数,也可用来定位和控制阿秒脉冲的时间参数.理论分析指出,只要选择合适的阿秒X射线能量带宽,CEP不稳定性对于光电子谱和测量结果的影响将大为降低,甚至在最大程度上消除这种影响.这些研究结果不仅有助于在物理上深入了解高次谐波辐射的动力学过程,而且对于进一步在实验上优化和选择阿秒单脉冲和双脉冲具有重要的参考和指导意义.

关键词：高次谐波产生鞍点方法谐波发射特性分布脉冲

Effective photon mass in nuclear matter and finite nuclei

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Effective photon mass in nuclear matter and finite nuclei

CCAST“不稳定核反应”研讨会

作者： Bao-Xi Sun, Xiao-Fu Lu, Peng-Nian Shen, En-Guang Zhao Institute of High Energy physics. The Chinese Academy of Sciences, P.O.Box 918(4), Beijing 100039. china Institute of theoretical physics, The Chinese Academy of Sciences, Beijing 100080, china Department of physics, Sichuan University, Chengdu 610064, china. Center of theoretical nuclear physics. national laboratory of heavy ion accelerator,lanzhou 73.000, china Department of physics, Tsinghua University, Beijing 100084, china and china Center of Advanced Science and Technology (World laboratory), Beijing 100080, china

＜正＞ Electromagnetic field in nuclear matter and nuclei are studied In the nuclear matter,because theexpectation value of the electric charge density operator is not zero,different in vacuum,the U（1）local gauge symmetry of electric charge is spontaneously broken and consequently,the photon gainsan effective mass through the Higgs mechanism An alternative way to study the effective mass of

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The L-shell ionization of Ho and Os induced by electron impact

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Chinese Science Bulletin 2006年第16期51卷 1929-1933页

作者： WU Zhangwen, GOU Chengjun, YANG Dailun, PENG Xiufeng, HE Fuqing & LUO Zhengming Key laboratory for Radiation physics and Technology of the Education Ministry of china Institute of nuclear Science and Technology, Sichuan University, Chengdu 610064, china *** Key laboratory for Radiation physics and Technology of the Education Ministry of china

The electron-induced L-shell X-ray par- tial production cross sections, total production cross sections and mean ionization cross sections for Ho and Os have been measured as functions of electron energies from near threshold up to 36 keV by using a thin target with thick substrate technique. The influ- ence of the electrons reflected from the substrate was corrected by using the electron transport biparti- tion model. Also, the corrected measured results were compared with theoretical predictions proposed by Gryzinski and McGuire.

关键词：钬锇电子冲击电离 X射线

Sum rules on quantum hadrodynamics

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Sum rules on quantum hadrodynamics

CCAST“不稳定核反应”研讨会

作者： Bao-Xi Sun, Xiao-Fu Lu, Peng-Nian Shen, En-Guang Zhao Institute of High Energy physics, The Chinese Academy of Sciences. P.O.Box 918(4), Beijing 100039, china Institute of theoretical physics, The Chinese Academy of Sciences, Beijing 100080. china Department of physics, Sichuan University, Chengdu 610064, china Center of theoretical nuclear physics, national laboratory of heavy ion accelerator.lanzhou 73.000. china Department of physics. Tsinghua University. Beijing 100084. china china Center of Advanced Science and Technology(World laboratory). Beijing 100080,china

＜正＞ A new method,sum rules on quantum hadrodynaznics,is developed to solve thenuclear many—body *** differences between this method and the relativis-tic Hartree—Fock approximation are *** theory with off-shell p...

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Study of light unstable nuclei via direact reactions

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Study of light unstable nuclei via direact reactions

International Conference on nuclear Structure physics

作者： Yanlin Ye School of physics and MOE key laboratory of heavy ion physics Peking University Beijing 100871 china

＜正＞Since the exotic properties of the unstable nuclei are mostly determined by a few weakly bound valence nucleons, the direct nuclear reaction, which are sensible to the surface distribution of the nuclear matter and especially to the valence nucleons, should be an appropriate tool to study the structure and property of exotic unstable nuclei.

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Measurement of Neutron Capture Cross Section for ^(180)Hf

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Chinese journal of nuclear physics 1997年第2期19卷 110-114页

作者： Chen Jinxiang Shi Zhaomin Tang Guoyou Zhang Guohui Institute of heavy ion physics,Peking University,Beijing 100871Lu Hanlin Han Xiaogang Huang Xiaolong china Institute of Atomic Energy,P.O.Box 275(3),Beijing 102413 北京大学重离子物理所北京中国原子能科学院北京

The neutron capture cross section for 180Hf relative to the 197Au（n,γ）198Au reaction ismeasured at neutron energies of 0.52,1.10 and 1.60 MeV using the activation *** of the products are measured with a high resolution HPGe detector gamma ray *** errors of the measured results are 5%～6%.Our results have a good agreementwith those of other authors within *** sections for the reaction are calculated withUNF code and recommended data are also given.

关键词： 100Hf 198Au Neutron capture cross section Activition method

heavy ion reactions around the Coulomb barrier

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中国科学：物理学、力学、天文学英文版 2011年第S1期54卷 6-13页

作者： ZHANG HuanQiao1, LIN ChengJian1, JIA HuiMing1, ZHANG ChunLei1,2, ZHANG GaoLong1,3, YANG Feng1, LIU ZuHua1, AN GuangPeng1, WU ZhenDong1, XU XinXing1 & JIA Fei1 1 china Institute of Atomic Energy, P. O. Box 275(10), Beijing 102413, china 2 Particle Astrophysics Center, Institute of High Energy physics, Chinese Academy of Sciences, Beijing 100039, china 3 School of physics and nuclear Energy Engineering, Beihang University, Beijing 100191, china 1. china Institute of Atomic Energy P. O. Box 275(10) Beijing 102413 China2. Particle Astrophysics Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100039 China3. School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China

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.

关键词： fusion-fission quasi-fission fusion hindrance fusion enhancement surface diffuseness parameter exotic nuclei

Relativistic mean-field approximation with density-dependent screening meson masses in nuclear matter

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Relativistic mean-field approximation with density-dependent...

CCAST“不稳定核反应”研讨会

作者： Bao-Xi Sun, Xiao-Fu Lu, Peng-Nian Shen, En-Guang Zhao Institute of High Energy physics, The Chinese Academy of Sciences, P.O.Box 918(4). Beijing 100039. china Institute of theoretical physics. The Chinese Academy of Sciences. Beijing 100080. china Department of physics. Sichuan University. Chengdu 610064. china Center of theoretical nuclear physics. national laboratory of heavy ion accelerator.lanzhou 73.000. china Department of physics. Tsinghua University. Beijing 100084. china china Center of Advanced Science and Technology (World laboratory). Beijing 100080.china

＜正＞ The self-energies of virtual a. w and neutral p mesons with zero time-space momentum are calculated in the relativistic mean-field approximation, then a rel-ativistic mean-field model with density-dependent screening meson masses is built. In this model, the nonlinear seif-coupling terms of mesons are not required.

关键词：

Evaluation and Calculation of Activation Cross Sections for 158,159Tb(n,2n), (n,3n), (n,γ) and (n,x) Reactions Below 20 MeV

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中国核科技报告 1997年第S2期 78-88页

作者： Yu Baosheng Han Yinlu Gao Lan (china nuclear Data Center, CIAE)Shi Zhaomin Tang Guoyou(Institute of heavy ion physics, Peking University)

IntroductionTb is a rare-earth element. Its activation cross section is a good indicator for nuclear science and technology applications. However, the evaluated data are very scarce in several nuclear data libraries. ... 详细信息

关键词： Evaluation and Calculation of Activation Cross Sections for n,x Reactions Below 20 MeV n,2n Tb and