浅谈用等效原理处理复杂运动问题

在研究物体运动时,经常遇到一些复杂的运动,有的是运动过程复杂,有的是运动轨迹比较特殊,觉得无从下手.如果能将分段的运动过程整合成单一的运动过程,将复杂的过程变成一个简洁的过程,将曲线运动等效为直线运动来处理,就可以使复杂问题简单化,使复杂运动简单化.下面通过具体实例来阐述之.     

对实物粒子使原子能级跃迁问题的商榷

某杂志中一篇关于原子能级跃迁的文章中,指出:若用电子等实物粒子作用在原子上,则原子跃迁是通过与实物粒子碰撞传递能量而实现,即只要人射实物粒子的能量E≥△E,均可使原子跃迁.此种说法笔者认为是片面的.     

塞曼效应实验中等高共轴调节问题探讨

借助带水准仪和三角支架的十字线激光器准确快捷调节塞曼效应实验系统中各光学元件等高共轴,观察到清晰的塞曼分裂图像,准确测量笔型汞灯处的磁场强度大小,大大减小了实验误差。     

Pre-Asymptotic Analysis of the Scattering Problem

JETP Letters - The pre-asymptotic analysis of the multichannel scattering problem for particles with an arbitrary spin and short-range interactions has been presented. The complete operator-valued...     

一道中考实验题的答案分析及教学启示

[题目]如图,在"观察水的沸腾"实验中 (1)水在沸腾时,温度计示数如图所示,此时水的沸点为____℃,表明当时的大气压强要比一个标准大气压____.     

Collision Index and Stability of Elliptic Relative Equilibria in Planar {n}-body Problem

In this article, we construct three new holomorphic vertex operator algebras of central charge 24 using the \({\mathbb{Z}_{2}}\)-orbifold construction associated to inner automorphisms. Their weight one subspaces have the Lie algebra structures D_7,3A_3,1G_2,1, E_7,3A_5,1, and \({A_{8,3}A_{2,1}^2}\). In addition, we discuss the constructions of holomorphic vertex operator algebras with Lie algebras A_5,6C_2,3A_1,2 and \({D_{6,5}A_{1,1}^2}\) from holomorphic vertex operator algebras with Lie algebras C_5,3G_2,2A_1,1 and \({A_{4,5}^2}\), respectively.     

光谱分析中空白与检出限的讨论

空白、检出限是分析化学中两个基本概念。本文拟从痕量分析的要求出发，以理论与实验数据结合的方式对几种空白及它们对检出限的影响进行了讨论。     

Analysis and Discussion About How to Determine the Variatiotnal Parameters in the Variational-Cumulant Expansion

Four methods of determining the variational parameter in the varia tional-cumulant expansion (VCE) are studied on the 2-dimensional Ising model. A comparison with the exact result shows that the main-variation method is the best one at low temperature, the completevariational method is better than others at high temperature, the accumulation-point method is the best one to approximate the intermediate coupling region, and each of the methods is analyzed from the original formulas or conjectures. Some suggestions are given in order to get optimal results. The VCE is also analyzed Gom a point of view of symmetry breaking for the first time.     

Majorana Solutions to the Two-Electron Problem

The two-electron atom is the simplest nontrivial quantum system not amenable to exact solutions. Today, its relevance in the development of quantum mechanics and its pedagogical value within the realm of atomic physics are widely recognized. In this work, an historical review of the known different methods and results devised to study such a problem is presented, with an emphasis to the calculations of the ground state energy of helium. Then we discuss several, related, unpublished results obtained around the same years by Ettore Majorana, which remained unknown till recent times. Among them a general variant of the variational method appears to be particularly interesting, even for current research in atomic and nuclear physics: it takes directly into account, already in the trial wavefunction, the action of the full Hamiltonian operator of a given quantum system. Further relevant contributions, specialized to the two-electron problem, include the introduction of the remarkable concept of an effective nuclear charge different for the two electrons (thus generalizing previous known results) and an application of the perturbative method, where the atomic number Z was treated effectively as a continuous variable. Finally a survey of results, relevant mainly for pedagogical reasons, is given; in particular we focus on simple broad range estimates of the helium ionization potential, obtained by suitable choices for the wavefunction, as well as on a simple alternative to Hylleraas’ method, which led Majorana to first order calculations comparable in accuracy with well-known order 11 results derived, in turn, by Hylleraas.     

The Sensitivity Analysis for the Flow Past Obstacles Problem with Respect to the Reynolds Number

In this paper, numerical sensitivity analysis with respect to the Reynolds number for the flow past obstacle problem is presented. To carry out such analysis, at each time step, we need to solve the incompressible Navier-Stokes equations on irregular domains twice, one for the primary variables; the other is for the sensitivity variables with homogeneous boundary conditions. The Navier-Stokes solver is the augmented immersed interface method for Navier-Stokes equations on irregular domains. One of the most important contributions of this paper is that our analysis can predict the critical Reynolds number at which the vortex shading begins to develop in the wake of the obstacle. Some interesting experiments are shown to illustrate how the critical Reynolds number varies with different geometric settings.