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1.
李增花  左维  陆广成 《中国物理》2004,13(11):1848-1853
The properties of hot asymmetric nuclear matter are studied in the framework of the finite temperature Brueckner-Hartree-Fock theory that is extended to include the contribution of microscopic three-body forces. We give the variation of the critical temperature with the asymmetry parameter and show the effect brought by this three-body repulsive potential on the value of the critical asymmetry of the phase transition for asymmetric nuclear matter. Owing to the additional repulsion provided by three-body forces, this value decreases. In addition, the domain of mechanical instability for hot nuclear matter is also indicated, which gradually shrinks with increasing asymmetry and temperature.  相似文献   
2.
Based on the difference between the Ferm/distributions at zero temperature and at the finite temperature, we introduce the temperature-dependent three-body force (TBF) into the microscopic finite-temperature Brueckner-Hartree-Fock theory (FTBHF). In terms of the meson-exchange current approach, i.e. the one boson exchange (OBE) approximation, the exchange of four important mesons π, ρ, σ and ω axe considered. Using the FTBHF theory including TBF, we describe the critical temperature of the liquid-gas phase transition for symmetric nuclear matter and discuss its change trend with the increasing asymmetry parameter. Compared to the result excluding TBF, the value of the critical temperature turns out to be smaller.  相似文献   
3.
Based on the facility of the Shanghai Laser Electron Gamma Source (SLEGS), the transmutation for nuclear wastes such as 137Cs and 129I is investigated. It is found that nuclear waste can be transmuted efficiently via photonuclear reaction triggered by gamma photons generated from Compton backscattering between CO2 laser photons and 3.5 GeV electrons. The nuclear activities of 137Cs and 129I are evaluated and compared with the results of transmutation triggered by bremsstrahlung gamma photons driven by ultra intense laser. Due to the better character of gamma photon spectrum as well as the high brightness of gamma photons, the transmutation rate of Compton backscattering method is much higher than that of the bremsstrahlung method.  相似文献   
4.
李增花  陆广成  左维 《中国物理 C》2003,27(12):1084-1088
利用Brueckner Hartree Fock和BCS理论方法,计算了β稳定中子星物质中处于1S0 态的质子和中子的对关联能隙,着重研究和讨论了三体核力的影响.结果表明三体核力对β稳定中子星物质中1S0态中子超流性的影响相对较小,但对1S0态质子超流性具有重要影响,而且其效应随核子数密度增大而迅速增强.三体核力的主要作用是强烈地抑制了高密度β稳定中子星物质中的1S0态质子超流性.  相似文献   
5.
利用Brueckner-Hartree-Fock和BCS理论方法,计算了非对称核物质中处于1S0态的质子和中子的对关联能隙,着重研究和讨论了能隙的同位旋依赖性和三体核力的影响.结果表明:随核物质的同位旋非对称度增大,中子1S0态超流相存在的密度范围逐渐缩小而且对关联能隙峰值稍有升高;质子1S0态超流相存在的密度范围迅速扩大而且对关联能隙峰值显著降低.三体核力对非对称核物质中1S0态中子超流性及其同位旋依赖性的影响相对较小,但对1S0态质子超流性具有重要影响,而且其效应随核子数密度增大而迅速增强.三体核力的主要作用是强烈地抑制了具有高非对称度的核物质中高密度区域的1S0态质子超流性,导致质子超流相存在的密度范围显著缩小.  相似文献   
6.
激光具有高强度、 高极化度等优异的性能。 用激光束轰击高能电子束就可以产生高强度、 高极化度的γ射线束。 上海激光电子γ源就是上海同步辐射装置上的这样一条束线站。 预计可以获得能量范围为1—22 MeV的准单色、 高强度(109—1011 s-1)和高极化度(线极化或圆极化)的γ射线束。 介绍了这条束线站目前的进展情况。 Shanghai Laser Electron Gamma Source (SLEGS) is a high intensity,short pulse and compact γ ray source which is based on inverse Compton scattering via interaction between pulsed high power laser beams and picosecond relativistic electron bunches. One of the attractive features of the laser Compton scattering is the easy control of polarization of the produced high energy photons that duplicates polarization of the applied laser beam. The γ ray with energy up to 22 MeV and intensity of 109—1011s 1 are expected to be produced by Compton backscattering of CO2 laser photons on the 3.5 GeV electrons bunches in the Shanghai Synchrotron Radiation Facility (SSRF). In this communication, we report same simulation results and the progressing status of SLEGS.  相似文献   
7.
The temperature dependent width of the fission fragment distributions was simulated in the Langevin equation by taking two-parameter exponential form of the fission fragment mass variance at scission point for each fission event. The result can reproduce experimental data well, and it permits to make reliable estimate for unmeasured product yields near symmetry fission.  相似文献   
8.
以有限温度Brueckner-Hartree-Fock(BHF)方法为基础,利用质量算子的空穴线展开,计算了不同温度和密度下的核物质中单核子势和核子有效质量,特别是研究和讨论了基态关联效应和三体核力贡献对热核物质中单核子势的影响. 研究表明,基态关联和三体核力对单核子势的密度和温度依赖性均有重要影响. 基态关联导致的重排修正具有排斥性,大大减弱了低动量区域单核子势的吸引性,而且基态关联效应对单核子势的贡献随密度增大而增强,随温度升高而减弱. 三体核力对基态关联的影响是导致单核子势中重排项贡献减小. 在高密 关键词: 有限温度BHF方法 质量算子空穴线展开 重排修正 单核子势 有效质量  相似文献   
9.
左维  陆广成  李增花  罗培燕 《中国物理 C》2005,29(11):1061-1066
通过引入微观三体核力, 扩展了有限温度Brueckner-Hartree-Fock方法. 利用这一扩展的理论模型, 研究了热核物质的状态方程和液气相变现象并计算了临界温度, 讨论了三体核力对液气相变临界点性质的影响并与Dirac-Brueckner-Hartree-Fock方法的理论预言进行了比较. 结果表明:三体核力对热核物质状态方程提供一个随密度和温度增大而增强的排斥贡献, 而且三体核力的排斥效应导致热核物质液气相变的临界温度明显降低.  相似文献   
10.
左维  陆广成  李增花  罗培燕 《中国物理 C》2005,29(12):1162-1166
在包含三体核力的有限温度Brueckner-Hartree-Fock理论方法基础上, 利用质量算子的空穴线展开, 研究了热核物质中基态关联所导致的对单核子势的重排修正项的密度和温度依赖性, 并讨论了三体核力对重排项的影响. 结果表明:单核子势的重排项贡献具有较强的密度和温度相关性, 重排项贡献随密度增加而增强并随温度升高而减弱. 在计算中引入三体核力会在一定程度上抑制基态空穴关联 效应, 从而导致单核子势的重排项贡献减小, 而且三体核力对重排项贡献的影响随密度增大而增强.  相似文献   
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