核反应过程中的核温度参量

结合我们以往的研究工作，对核温度的测量原理，测量方法及各种方法的可靠性，存在的问题等进行了一些讨论，尤其对核反应中核温度参量与核反应中的轻粒子的发射谱，粒子非稳态相对布居及同位素产额的依赖关系进行了一些分析和讨论     

核温度测量与粒子能量的关系

提取了30MeV/u ⁴⁰Ar+natAg反应中后角出射的同位素(^6,7Li,^3,4He)产额比温度为5MeV.观察到这一同位素产额比温度随阈值能量E_cut/A的增加而逐渐由5MeV上升到6MeV.为进一步研究这一变化关系,用Monte Carlo方法模拟了热核蒸发粒子的过程,表明随粒子能量的增加,发射该能量粒子的发射源平均温度也在增加.说明高温热核发射高能量粒子的几率大.     

30MeV/u 40Ar+112,124Sn反应中的同位素产额比与核温度

系统研究了30MeV/u^40Ar ^112,124Sn反应中的轻粒子同位素产额比随角度和初始激发能的变化关系,对于两个反应体系,均观察到3He/^4He和^6Ni/^7Li的产额比随角度的增加而增加,^6He/^4He和^8Li/^7Li随角度的增加而减少,统计发射的运动学效应不能完全符合实验结果,各种单同位素产额比与靶核的N／Z比有关,表现出同位旋效应,而由双同位素比提取的核温度几乎没有靶核相关性。     

46.2MeV/u 12C+64Ni、58Ni反应中发射的轻粒子和复杂碎片

用光二极管读出的CsI(Tl)闪烁探测器和多叠层硅望远镜,测量了46.2MeV/u ¹²C引起各种靶⁶⁴Ni、⁵⁸Ni、¹²C、¹⁹⁷Au、²⁰⁹Bi反应中所发射的轻粒子和中等质量碎片,这些探测器对轻粒子和中等质量碎片有很好的能量分辨和质量分辨.单举的能谱用运动源模型进行了分析,对各种靶在不同角度的中等质量碎片的产额进行了比较.由单举数据推出同位素产额比随靶质量变化的系统性,讨论了N/Z自由度的平衡.     

30MeV/u 40Ar引起的反应中核温度参数的提取

利用同位素产额比方法,提取了30MeV/u ⁴⁰Ar轰击⁵⁸Ni,⁶⁴Ni和¹¹⁵In的反应中中等质量碎片(IMFs:3≤Z≤8)的发射体的核温度参数,给出了“表观”温度与一些物理量的依赖关系以及对边馈(side-feeding)效应的影响进行修正后的温度参数. 并就此进行了简单的讨论.     

轻入射粒子核反应系统的核势研究

从核与核作用的弹性散射出,收集各种能量和各种反应系统的光学模型参数和反应截面,分析有效核力作用,给出势能分布;并与常见的几种核势的描述方式比较,发现轻入射粒子系统的核势存在系统偏离,用亲近势的形式进行了重新拟合.     

核反应能谱的中段连续谱研究之一:裂解-聚合反应机制的贡献

本文介绍了裂解-聚合反应机制对核反应能谱的中段连续谱的贡献.这个反应机制认为炮弹在靶核势场中经历了裂解及与靶核聚合两步过程.本文给出了一个处理裂解-聚合机制的有限程计算的理论方法.并把这一理论应用于α粒子轰击重不同的靶核的一系列核反应.理论与实验的比较证实裂解与聚合反应机制是对中段连续谱的主要贡献.     

30MeV/u40Ar+112,124Sn反应中的同位素产额比与核温度

系统研究了30MeV/u ⁴⁰Ar+^112,124Sn反应中的轻粒子同位素产额比随角度和初始激发能的变化关系.对于两个反应体系,均观察到³He/⁴He和⁶Li/⁷Li的产额比随角度的增加而增加,⁶He/⁴He和⁸Li/⁷Li随角度的增加而减小.统计发射的运动学效应不能完全符合实验结果.各种单同位素产额比与靶核的N/Z比有关,表现出同位旋效应,而由双同位素比提取的核温度几乎没有靶核相关性.     

MEND程序中能谱的计算方法

给出了在中能区(≤250MeV)多次粒子发射过程中计算各种出射轻粒子及各种反冲核之能谱的方法,指出它的计算效率远高于(两个数量级以上)传统方法,并给出了两个算例.     

核壳纳米结构壳中Yb离子对稀土上转换发光温度特性的影响

采用油酸盐法分别制备出均匀的上转换发光裸核纳米粒子及其包覆具有不同Yb³⁺浓度掺杂的NaYF₄:Yb³⁺,Er³⁺核壳纳米结构的上转换纳米粒子。在不同温度下(90~450 K),研究分析了在壳中掺杂不同浓度Yb³⁺的NaYF₄:Yb³⁺,Er³⁺@NaYF₄:x%Yb³⁺核壳纳米体系的上转换发光特性。结果表明:在NaYF₄:Yb³⁺,Er³⁺上转换体系中,惰性壳中的525 nm(²H_11/2 →⁴I_15/2)发射峰呈现出与活性壳中不一样的趋势。壳层中掺杂的Yb³⁺通过声子对纳米粒子内部发光与表面及外界之间的相互作用起到了重要的"桥"连作用。     

Extraction of Nuclear Matter Properties from Nuclear Masses by a Model of Equation of State

The extraction of nuclear matter properties from measured nuclear masses is investigated in the energy density functional formalism of nuclei.It is shown that the volume energy a1 and the nuclear incompressibility Ko depend essentially on μ_nN + μ_pZ - 2E_N,whereas the symmetry energy J and the density symmetry coefficient L as well as symmetry incompressibility Ks depend essentially on μ_n - μ_p,where μ_p ＝μp - ∂E_c/∂Z,μ_n and μ_p are the neutron and proton chemical potentials respectively,E_N the nuclear energy,and E_c the Coulomb energy.The obtained symmetry energy is J ＝ 28.5 MeV,while other coefficients are uncertain within ranges depending on the model of nuclear equation of state.     

Extraction of Nuclear Matter Properties from Nuclear Masses by a Model of Equation of State

The extraction of nuclear matter properties from measured nuclear masses is investigated in the energy density functional formalism of nuclei.It is shown that the volume energy a1 and the nuclear incompressibility Ko depend essentially on μnN - - pZ - 2EN,whereas the symmetry energy J and the density symmetry coefficient L as well as symmetry incompressibility Ks depend essentially on μn - μp,where μp ＝μp - Ec/ Z,μn and μp are the neutron and proton chemical potentials respectively,EN the nuclear energy,and Ec the Coulomb energy.The obtained symmetry energy is J ＝ 28.5 MeV,while other coefficients are uncertain within ranges depending on the model of nuclear equation of state.``     

Anomalous Ortho-to-Para Ratio of Nuclear Spin Isomers of H2O at Low Temperatures

A theoretical model proposed for nuclear spin isomers of H₂O molecules located inside the C₆₀ fullerene explains an anomalously high stability of ortho-H₂O isomers detected in the experiments reported in [B. Meier et al., Nature Commun. 6, 8112 (2015)] at a temperature of T = 5 K.

     

Compression Properties of Finite Nuclear Matter at Zero and Finite Temperatures with the Skyrme Force SKM

By taking into account the finite-size effect rationally in the framework of the Hartree-Fock theory, compression properties at zero and finite temperatures of finite nuclear matter are investigated with the Skyrme force SKM^*. Energies of the isoscalar giant monopole resonance of nuclei at zero temperature calculated are found to be in agreement with experimental and empirical values.     

The Excitation Temperatures of Nonmetal Atoms and the OH Temperatures in Microwave-Induced Plasma

Abstract

The excitation temperatures of nonmetal atoms and the OH molecule temperatures have been measured in argon MIP, operating under atmospheric pressure at different experimental conditions. Atoms of Ar I, P I and H have been used as thermometric species. The rotational and vibrational temperatures have been obtained from the OH A²Σ⁺ - X²? band spectra. The ^SR₂₁ ratational lines have been used for the first time for the temperature measurements. The energy distributions observed here are discussed.     

27Al+27Al耗散反应中间双核系统的核温度

从²⁷Al+²⁷Al耗散反应产物的激发函数中提取能量相干宽度Г,再求出双核系统的核温度T,并用相干转动的概念进行以合与解释.     

Extraction of Nuclear Temperature in 27Al+27Al Dissipative Collision

Energy coherence widths of the dissipative products in the collision ²⁷Al+²⁷Al are extracted from measurement of the excitation functions. Then, the nuclear temperature T of the intermediate dinuclear system are determined, and discussed by using a concept of coherence rotation.     

Temperatures from rotational-vibrational raman Q-branches

An iterative, least-squares analysis scheme, based on the differential of the intensity, dI = dτ?I/?τ + d? ?I/?? has been developed for obtaining the temperature θ = 1/τ and density ? from a set of rotational-vibrational Raman, Q-branch intensities. Spectral locations that cover the maximum variation in ?I/?τ were determined from a set of computed intensities and derivatives. The results for the Stokes (anti-Stokes) bands indicate for temperatures less than 2100K (2700K) that the maximum extent of ?I/?τ can be spanned by recording intensities only in the first two vibrational bands, v(1-0) and v(2-1) and, due to the multivalued nature of ?I/?τ, equally spaced values for ?I/?τ can be obtained only by programming the spectrometer to select an appropriate set of non-uniformly spaced passbands.     

Temperatures in a hollow-catmode discharge

Rotational and vibrational temperatures of He, O₂. and CO₂have been examined in carbon and molybdenum cathodes as functions of pressure and discharge current. The rotational temperature is strongly dependent on the conditions. The rotational temperatures of CO⁺, N ₂ ⁺ , C₂, CN, and OH are identical in simultaneous measurements.     

核数据和核模型方法

简要介绍了国际上发展中的核科学和技术及其应用对微观核数据的需求和核数据理论计算中现有标准程序的基本情况,并做了相应的分析和比对 .同时也简要介绍了国际上核数据理论计算中模型方法研究的新进展.Developing nuclear data needs towards to sustainable development on fission reactor design and many nuclear applications out the field of fission reactor technology that are growing economic significance and that have substantial data requirements are introduced. International standard codes used in nuclear data evaluation and calculation are presented and compared with each other. Generally speaking, three rather wide groups of nuclear reaction models used usually are also described...