CALCULATION OF THE EFFECTIVE MOMENT OF INERTIA OF FISSIONING NUCLEI AT SADDLE POINT

The effective moment of inertia,charge density distributions of the fissioning nucleus ¹⁷⁰Yb and ²⁵⁴Fm at saddle point are calculated by using the continuous medium model with variable densities.     

ANGULAR DISTRIBUTIONS OF FISSION FRAGMENTS AND THE SHAPES OF THE SADDLE POINT OF COMPOUND NUCLEI

We have measured the angular distributions of fission fragments for a series of compound nuclei formed in the bombardment of ¹⁶⁹Tm, ¹⁷⁵Lu, ¹⁸¹Ta, ¹⁹⁷Au, ²⁰⁹Bi, ²³²Th and ²³⁸U by 78 MeV ¹²C ions and in the bombardment of natural lead by 96.6, 92.2, 88.1, 79.0 and 75.6 MeV ¹⁴N ions with mica track detectors. All the measured angular distributions can be fitted by the theoretical formula given by Halpern and Strutinski. The effective moments of inertia of the fissioning nuclei at the saddle point are derived from the angular distribution anisotropies. A comparison is made for the shapes of experimental saddle point with the theoretical predictions by the liquid drop model.     

裂变碎块角分布与鞍点结构

从Jacob和Wick所推导的具有自旋粒子的散射矩阵元一般表示式出发,采用适当近似后,分析了中子引起Th²³⁰,Th²³²,U²³⁴,U²³⁶,U²³⁸裂变的阈能附近碎块角分布的实验数据。分析结果说明:1)阈能附近碎块角分布可以用裂变是通过鞍点上少数转动带(每一带具有确定的宇称)来解释;2)这些转动带与Nilsson的渐近能谱图所预言的基本上一致。同时利用对称裂变鞍点比非对称裂变鞍点高的观点,讨论了裂变碎块角分布各向异性与质量比之间的关系。     

MICROSCOPIC CALCULATION OF THE INERTIA IN HEAVY NUCLEI

A realistic calculation of the inertia for ²³⁶U fisson based on the linear response theory is presented, in which the single particle states are provided by Nilsson model. The dependence of the nuclear inertia M_δiδi on the collective variables δ₂, δ₄ is studied at the range of certain nuclear temperature (0—1 MeV). The pairing effect and the shell effect on the nuclear inertia are discussed. The calculated results show a very prominent structure at level crossing points and when acrossing the critical temperature.     

THE MOMENT OF INERTIA IN THE INTERACTING BOSON-FERMION MODEL

For a system described by the interacting boson-fermion model (IBFM),we construct the intrinsic states and study the moment of inertia of deformed odd-A nuclei in terms of the selfconsistent cranking calculation.An approximate analytic method for the energy spectrum is presented in the general cases where the IBFM Hamiltonian does not have dynamical symmetry.The rationality of this method is also discussed by taking ^153,155,157Eu isotopes as examples.     

旋转带电球体的转动惯量

对均匀带电球体绕其自身的对称轴作变角速度旋转产生的磁场和感应电场求解，之后计算了这球体对该轴的转动惯量。     

刚体绕任意轴转动惯量的简便计算

利用微元求和的方法给出几种刚体对于过质心任意轴的转动惯量公式，并由此引出转动惯量与刚体几何对称性的联系，以及与转动惯量有关的几何形体等价性的一些结果．     

原子核的转动惯量和gR因子

基于Inglis的推转模型(cranking model),我们利用Nilsson波函数对原子核转动惯量及集体运动g_R,因子作了仔细的计算,计算结果相当满意,无论在数值上,或是随不同原子核的变化,以及随不同激发带的变化上都和实验结果相近。其原因可能是由于选择了一个较恰当的、含有强自旋轨道耦合的轴对称自洽场。     

用扭摆法测定物体转动惯量

本文简要地介绍了我校工科物理实验引进德国实验设备，用扭摆测定物体转动惯量的仪器装置和方法     

极化子有效质量与温度的关系

本文计及离子晶格的原子结构,用紧束缚法导出了极化子的自陷能和有效质量,给出了有效质量与温度的关系。 关键词：     

气垫导轨在刚体转动惯量测定实验中的应用

本文介绍了一种测量刚体转动惯量的新方法。即把气垫导轨和刚体转动仪结合起来来测量刚体的转动惯量,使传统的气垫导轨实验和刚体转动惯量测定实验得以更新,提高了实验测量的精度,拓展了实验内容。     

Frankel激子的有效质量与温度的关系

本文计及离子晶格的原子结构,用紧束缚方法导出了Frankel激子的有效质量与温度的关系。 关键词：     

刚体惯量主轴与其上任一点的惯量主轴之关系

刚体的惯量主轴与惯量主轴上任一点的惯量主轴之间的关系问题，一般的力学、理论力学教科书大多没有提及，本文就此问题作了一些研究讨论．     

SURFACE ENERGIES OF ATOMIC NUCLEI AND THE MASS OF THE SCALAR MESON

Assuming that the nuclear binding is dominated by a real scalar meson field,the mass of this meson is calculated to be 472 MeV from the nuclear surface tension coeffici-ent,by Thomas-Fermi method and Van der Waals approximation.The agreement between this value and the mass of a chief scalar meson in the OBEP theory of nuclear force indicates that a more serious investigation of above assumption should be valuable.     

DEPENDENCE OF PHASE TRANSITION ON THE MASS NUMBER OF HOT NUCLEI

The dependence of phase transition,associated with the disassembly of hot nuclei,on the mass number of hot nuclei is investigated.By studying six hot nuclei ranging from ⁵⁶Ni* to ²³⁸U*,we find that in the curves of excitation energy of hot nuclei vs.Thermodynamic temperature T(E*) of ⁶³Cu* and heavier ones there are always two temperature plateaus,but in T(E*) of ⁵⁶Ni the first temperature plateau (at lower excitation energy) shrinks into a kink.     

含成层杂质的复合媒质的电导性质

本文用瑞利模型研究含成层杂质的复合媒质的直流电导性质,推导了适用于此类复合媒质的广义瑞利恒等式,并定义系统的有效电导率。对于具有立方对称性的系统,给出复合媒质有效电导率的解析计算公式。 关键词：     

利用刚体转动惯量实验仪验证转动定律的设计

介绍了设计性实验“利用刚体转动惯量实验仪验证转动定律”.该实验要求学生理解刚体动力学原理;利用实验室现有的仪器,对刚体转动惯量实验仪进行改装;提出新的实验原理,可以对阻力矩进行估测,利用该实验装置验证刚体定轴转动定律.     

用霍尔开关测量刚体转动惯量实验中的时间变量

本文使用集成霍尔开关传感器改进刚体转动实验，计算刚体转动惯量和摩擦力矩，提高了测量精度。     

源具有质量多极矩的静态引力场稳定性研究

通过对具有质量多极矩的静态黑洞视界附近的Hawking辐射的研究,发现这类黑洞的存在将违背黑洞热力学定律.对这类引力场进行线性微扰,发现在尘埃物质扰动下,这类黑洞是不稳定的.故宇宙中可能不存在具有质量多极矩的静态黑洞. 关键词：     

Serret—Frenet公式与质点的空间曲线运动

用自然坐标系中空间曲线上活动三标架的Serret—Frenet公式,指出了一本理论力学教学参考书中的一个错误,表明质点在做空间曲线运动时公式dn^/dt=-θ·τ^不再成立,最后用Darboux矢量及转动系在静止系中的变化率公式阐明其运动学意义.