157,159Tm基态附近性质的研究

利用可变转动惯量的三轴粒子-转子模型研究了^157,159Tm低激发正宇称态的性质,理论值和实验值比较好的符合表明¹⁵⁷Tm和¹⁵⁹Tm是三轴形变核,指出实验还给出了¹⁵⁷Tm另一条激发转动带.     

Influence of inertia,topography and gravity on transient axisymmetric thin‐film flow

This study examines theoretically the development of early transients for axisymmetric flow of a thin film over a stationary cylindrical substrate of arbitrary shape. The fluid is assumed to emerge from an annular tube as it is driven by a pressure gradient maintained inside the annulus, and/or by gravity in the axial direction. The interplay between inertia, annulus aspect ratio, substrate topography and gravity is particularly emphasized. Initial conditions are found to have a drastic effect on the ensuing flow. The flow is governed by the thin‐film equations of the ‘boundary‐layer’ type, which are solved by expanding the flow field in terms of orthonormal modes in the radial direction. The formulation is validated upon comparison with the similarity solution of Watson (J. Fluid Mech 1964; 20 :481) leading to an excellent agreement when only 2–3 modes are included. The wave and flow structure are examined for high and low inertia. It is found that low‐inertia fluids tend to accumulate near the annulus exit, exhibiting a standing wave that grows with time. This behaviour clearly illustrates the difficulty faced with coating high‐viscosity fluids. The annulus aspect is found to be influential only when inertia is significant; there is less flow resistance for a film over a cylinder of smaller diameter. For high inertia, the free surface evolves similarly to two‐dimensional flow. The substrate topography is found to have a significant effect on transient behaviour, but this effect depends strongly on inertia. It is observed that the flow of a high‐inertia fluid over a step‐down exhibits the formation of a secondary wave that moves upstream of the primary wave. Gravity is found to help the film (coating) flow by halting or prohibiting the wave growth. The initial film profile and velocity distribution dictate whether the fluid will flow downstream or accumulate near the annulus exit. Copyright © 2004 John Wiley & Sons, Ltd.     

Blocking Effect and Moments of Inertia of K = 1/2 Rotational Band in 171Yb

The K = 1/2 rotational band in 171yb is investigated using the particle number conserving (PNC) method for treating the cranked shell model with monopole and quadrupole pairing interactions. The experimental moments of inertia of 171 Yb [521]1/2 (signature α = 1/2) are reproduced well by the PNC calculation, in which no free parameter is involved. The difference in the contribution to the moment of inertia between protons and neutrons is mainly due to the blocking effect of neutron normal orbitals. The ω variation of the occupation probability of each cranked orbital and the contribution to the moment of inertia from each major shell and from each cranked orbital are investigated.     

A≈190质量区奇A核超形变带的系统研究

利用包括多体相互作用和具有SO(5)(或SU(5))对称性的对转动对称微扰的超对称模型方法,对A≈190质量区奇A核的超形变转动带进行系统的研究,无论是E2跃迁γ射线能谱,还是动力学转动惯量都得到与实验结果很好定量符合的结果.这表明,超对称方法不仅可以很好地描述超形变带的整体性质,还可以很好地描述超形变带的ΔI=4分岔和全同带等奇异现象.     

超形变奇-奇核194Tl中的双堵塞效应

采用处理含有对力的推转壳模型的粒子数守恒方法研究了A～190区奇奇核194Tl中6条超形变带. 计算结果与实验符合得非常好. 根据我们的PNC计算结果,分别指定了194Tl的6条超形变带的组态,详细分析了质子和中子的堵塞效应对转动惯量的影响. 转动惯量随转动频率的变化主要来源于高N闯入壳(对中子N=7,对质子N=6)的贡献,而其他大壳对转动惯量的贡献基本上不随转动频率变化.     

Equations of motion for a (non‐linear) scalar field model as derived from the field equations

The problem of derivation of the equations of motion from the field equations is considered. Einstein's field equations have a specific analytical form: They are linear in the second order derivatives and quadratic in the first order derivatives of the field variables. We utilize this particular form and propose a novel algorithm for the derivation of the equations of motion from the field equations. It is based on the condition of the balance between the singular terms of the field equation. We apply the algorithm to a non‐linear Lorentz invariant scalar field model. We show that it results in the Newton law of attraction between the singularities of the field moved on approximately geodesic curves. The algorithm is applicable to the N‐body problem of the Lorentz invariant field equations.     

超变形转动带的自旋指定与实验测定的比较

按照转动带自旋指定的3种方案,分析了A～190区偶偶核中已测到的超变形带. 对于¹⁹⁴Hg(1)和¹⁹⁴Pb(1),分析给出的自旋指定与实验值完全一致. 有理由认为,其它10条超变形带的自旋指定也是可信的,否则要重新审查现有的转动谱理论,而这些理论对于正常形变核转动带已证明是完全正确的.     

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．     

Ignoring heat inertia impairs accuracy of determination of activation energy in thermal analysis

This paper critically analyzes the traditional method of kinetic determination of activation energy by sectioning the recorded differential thermal analysis peak area. This procedure is incorrect because it misses the impact of thermal inertia, which changes the shape of the peak's base line from straight to s-shape. This effect has been known since the Newton cooling law, but the resulting errors persist to be interwoven into all the kinetic methods based on nonisothermal thermoanalytical measurements. Relating to calorimetry, it is necessary here because heat inertia has become a standard part of heat determination via using the Tian historical equation. The role and impact of heat inertia is discussed and analyzed in detail.