Modifications of Electron States,Magnetization, and Persistent Current in a Quantum Dot by Controlled Curvature

The thin‐layer quantization procedure is used to study the physical implications due to curvature effects on a quantum dot in the presence of an external magnetic field. Among the various physical implications due to the curvature of the system, the absence of the $m=0$ state is the most relevant one. This absence affects the Fermi energy and consequently the thermodynamic properties of the system. In the absence of magnetic fields, it is verified that the rotational symmetry in the lateral confinement is preserved in the electronic states of the system and its degeneracy concerning the harmonicity of the confining potential is broken. In the presence of a magnetic field, however, the energies of the electronic states in a quantum dot with curvature are greater than those obtained for a quantum dot in a flat space, and the profile of degeneracy changes when the field is varied. It is shown that the curvature of the surface modifies the number of subbands occupied in the Fermi energy. In the study of both magnetization and persistent currents, it is observed that Aharonov–Bohm‐type oscillations are present, whereas de Haas–van Alphen‐type oscillations are not well defined.     

Effect of curvature on interfacial segregation: Electronic contribution to the point defect/interface binding energy

The electronic contribution to the driving force for segregation to a curved interface between a cylindrical fiber of insulator embedded in a metal matrix is calculated. The solute/curved-interface binding energy is shown to vary as the inverse of the radius of curvature of the interface in the limit of a small radius. This result implies that the propensity for segregation of curved interfaces is larger than that of planar interfaces.     

Radiation from a Charge Supported in a Gravitational Field

We examine whether a charge supported statically in a gravitational field radiates, and find the answer to this question to be positive. Based on our earlier results we find that the important condition for the creation of radiation is the existence of a relative acceleration between the charge and its electric field, where such an acceleration causes the curving of the electric field and the creation of a stress force due to this curvature. This stress force is the reaction force, which creates the radiation. Later we find that this condition do exist for a charge supported statically in a gravitational field, where the electric field of the charge falls in the gravitational field, it curves, and the stress force raised in this curved field, creates electromagnetic radiation.     

有间隙弯叶片近壁面静压分布对叶栅气动性能的影响

对具有叶顶间隙的直叶栅、正弯叶栅和反弯叶棚的近壁画静压和出口流场进行了测量，实验结果发现：叶片正弯减小了叶顶中后部的横向压力梯度，削弱了泄漏流与端壁横流及其相互作用，使下游流动损失明显降低；叶片反弯也削弱了泄漏流动，但下游流动损失比其它两套叶栅大．     

Dirac Equation from the Hamiltonian and the Case With a Gravitational Field

Starting from an interpretation of the classical-quantum correspondence, we derive the Dirac equation by factorizing the algebraic relation satisfied by the classical Hamiltonian, before applying the correspondence. This derivation applies in the same form to a free particle, to one in an electromagnetic field, and to one subjected to geodesic motion in a static metric, and leads to the same, usual form of the Dirac equation—in special coordinates. To use the equation in the static-gravitational case, we need to rewrite it in more general coordinates. This can be done only if the usual, spinor transformation of the wave function is replaced by the 4-vector transformation. We show that the latter also makes the flat-spacetime Dirac equation Lorentz-covariant, although the Dirac matrices are not invariant. Because the equation itself is left unchanged in the flat case, the 4-vector transformation does not alter the main physical consequences of that equation in that case. However, the equation derived in the static-gravitational case is not equivalent to the standard (Fock-Weyl) gravitational extension of the Dirac equation.     

新的圆柱壳剪切屈曲方法及实验分析

提出用两块曲板、简易的夹具及普通万能试验机来进行半径Ｒ≥１０００ｍｍ的圆柱壳剪切屈曲实验．解决了使用单块曲板实验剪流合力不易通过剪力中心的难题．也避免了使用薄壁圆筒或封闭筒体扭转方案的一些缺点．实验结果与有限元计算分析以及国外成熟结果比较，符合良好．     

曲线边界差分方程研究

近代传热工程的研究,不仅丰富了解析解法,而且使数值解法得到了迅速发展。其中有限差分法和有限单元法,是处理较复杂传热问题的有力工具。第一部分介绍两维Taylor级数展开,说明建立曲线边界节点差分方程式的数学方法。第二部分为推荐的简便实用方法,着重描述曲线边界控制体的各种取法,以及应注意的几条原则。第三部分详细列出了予测两维稳定导热温度场的解题步骤,使差分方程式的数学推导和物理概念密切结合起来。最后引用较精确的有限单元法计算实例的结果,证实介绍的简便方法计算结果是较准确的.     

The n-Wave Procedure and Dimensional Regularization for the Scalar Field in a Homogeneous Isotropic Space

We obtain expressions for the vacuum expectations of the energy–momentum tensor of the scalar field with an arbitrary coupling to the curvature in an N-dimensional homogeneous isotropic space for the vacuum determined by diagonalization of the Hamiltonian. We generalize the n-wave procedure to N-dimensional homogeneous isotropic space–time. Using the dimensional regularization, we investigate the geometric structure of the terms subtracted from the vacuum energy–momentum tensor in accordance with the n-wave procedure. We show that the geometric structures of the first three subtractions in the n-wave procedure and in the effective action method coincide. We show that all the subtractions in the n-wave procedure in a four- and five-dimensional homogeneous isotropic space correspond to a renormalization of the coupling constants of the bare gravitational Lagrangian.     

进口附面层厚度对弯叶片扩压叶栅损失的影响

本文通过人工加厚叶栅进口附面层厚度，考察了叶搬进口附面层厚度对弯叶片扩压叶栅损失的影响．实验结果表明，进口附面层厚度增加时，叶栅两端区二次流增强，叶栅损失增大．采用正弯曲叶片在参考进口附面层状态和人工加厚附面层时均未得到叶栅损失的降低，而反弯曲叶栅损失的降低出现在参考进口附面层状态下．     

NONMONOTONE CURVED SEARCH METHODS FOR UNCONSTRAINED OPTIMIZATION

In this paper two nonmonolone curved search (NCS) algorithms fur unconstrained optimization are presented. The NCS algorithms possess both a global convergence properly and a quadratic rale of convergence. Some numerical results are also reported which show that the NCS algorithn is superior to the usual curved search (UCS)aIgorithm for typical lest problems.