中子和带电粒子光学势

叙述了中子与质子的光学模型势、存在的问题及研究的新课题．同时还涉及到核数据的应用等方面． The opticle potential for neutrons and charged particles,there existed problems,new research topic are described.The application on the nuclear data is also involved.     

A Fractal Model for the Effective Thermal Conductivity of Granular Flow with Non—uniform Particles

The equipartition of energy applied in binary mixture of granular flow is extended to granular flow with non-uniform particles.Based on the fractal characteristic of granular flow with non-uniform particles as well as energy equipartition,a fractal velocity distribution function and a fractal model of effective thermal conductivity are derived.Thermal conduction resulted from motions of particles in the granular flow,as well as the effect of fractal dimension on effective thermal conductivity,is discussed.     

Determining Optimum Conditions for Measuring by Gamma-ray Backscattering

The paper is concerned on the calculation of the optimal thickness of measured material from the point of view of measurement error. The minimum relative error of a measurement is determined as a function of the gamma radiaiton linear attenuation coefficient and the thickness of the material used. Various types of fluctuations are considered and attention is paid to the background detected in the same arrangement without measured material. The results are summarized into simple figures. The conclusion is made that the optimal thickness increases with poorer quality of the measuring instrument.     

用积分方程方法决定胶粒之间的空耗势

用硬球模中性胶体粒子 ,数值求解双组分Ornstein Zernike积分方程 (当大的中性胶体粒子的浓度为零时 ) ,用来决定悬浮在溶剂 (用小的硬球模拟 )中两个胶粒之间的空耗势 .所预言的空耗势与文献的模拟数据和实验数据能很好地符合 .研究发现 ,基于空耗势的有效一组分Hansen Verlet一相相变标准完全不能预言双组分系统的液 固相变 .讨论了导致这种现象的原因 :Hansen Verlet一相相变标准不能自地处理有效一组分系统中固相与液相的体积能     

Pair Interaction Potential of Particles for Two‐Component Plasma

In this work the semiclassical potential for plasma particles pair interactions, which takes into account the diffraction effects due to the uncertainty principle in two‐component plasma (the region of temperatures 10⁴K < T < 10⁸K and densities 10²¹cm^–3 < n ≤ 10²⁴cm^–3), was proposed. The values of this potential were numerically calculated and an interpolation formula was obtained (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

MgB2颗粒超导体临界电流的温度特性研究

通过制备MgB2/MgO超导复合材料,获得了典型的MgB2弱连接颗粒超导体,并测量了该样品在不同温度下的Ⅰ-Ⅴ特性曲线.在Ⅰ-Ⅴ曲线中,我们发现:当电流超过临界电流时,电压随着电流先是缓慢的增长,在电流升到一定值时,电压有一个很陡的突变.我们对这一变化进行了研究,认为这是由于MgO杂质使MgB2的晶界效应增强所引起的.该样品的临界电流和温度的关系满足:jc(T)∝(1-T/Tc)1/3,利用三维Josephson结网络系统的渗流模型进行计算发现,当颗粒超导系统处于非均匀状态时,临界电流和温度满足关系式jc(T)∝(1-T/Tc)4/3,这一结果和我们的实验符合的非常好.     

Sedimentation of Brownian Particles in a Gravitational Potential

The settling of a Brownian particle in a semi-infinite fluid bounded by a bottom plane is studied on the basis of Smoluchowski's exact solution of the equation describing diffusion in the gravitational potential. Expressions are derived for the mean height and the variance of height at some time after starting at an initial height. These quantities show interesting behavior as a function of time. It is shown that for certain initial heights the Boltzmann entropy does not increase steadily. It increases at first but then decreases to its equilibrium value.     

正弦平方势与带电粒子的准沟道辐射

在经典力学框架内,描述了带电粒子自发辐射的频谱分布与辐射频率;利用正弦平方势讨论了带电粒子准沟道辐射,指出了准沟道辐射与系统的旋转周期解相联系;分析了系统的相平面特征和准沟道粒子进入混沌的可能途径. In the general case the spectral distribution and the radiation frequency are derived for the spontaneous radiation of charged particles. The quasichanneling radiation is described by using a sine square potential, and point out that the quasichanneling radiation is related directly to the rotation periodic solution; The properties of the phase plane and the possible model approaching to chaos for the system is analyzed.     

Clusterization of Stochastically Wandering Particles in Potential Fields

Computer models belonging to the class of models of growth controlled by a gradient are investigated. A theoretical approach to the construction of model algorithms of this class allows us to obtain a wide variety of clusters with different structures, including fractal ones. A consideration of gradient increments to the potential leads to the formation of vertical, nonbranching, and insulated clusters corresponding to a long-range potential with large gradient.     

Multiple Reflections for Classical Particles Moving under the Influence of a Time-Dependent Potential Well

We study the dynamics of classical particles confined in a time-dependent potential well. The dynamics of each particle is described by a two-dimensional nonlinear discrete mapping for the variables energy en and phase ϕn of the periodic moving well. We obtain the phase space and show that it contains periodic islands, chaotic sea, and invariant spanning curves. We find the elliptic and hyperbolic fixed points and discuss a numerical method to obtain them. We study the dispersion of the initial conditions after a single iteration. This study allows finding regions where multiple reflections occur. Multiple reflections happen when a particle does not have enough energy to exit the potential well and is trapped inside it, suffering several reflections until it has enough energy to exit. We also show deformations in regions with multiple reflection, but the area remains constant when we change the control parameter NC. Finally, we show some structures that appear in the e0e1 plane by using density plots.     

Zeta Functions for the Spectrum of the Non-Commutative Harmonic Oscillators

This paper investigates the spectral zeta function of the non-commutative harmonic oscillator studied in [PW1, 2]. It is shown, as one of the basic analytic properties, that the spectral zeta function is extended to a meromorphic function in the whole complex plane with a simple pole at s=1, and further that it has a zero at all non-positive even integers, i.e. at s=0 and at those negative even integers where the Riemann zeta function has the so-called trivial zeros. As a by-product of the study, both the upper and the lower bounds are also given for the first eigenvalue of the non-commutative harmonic oscillator.Work in part supported by Grant-in Aid for Scientific Research (B) No. 16340038, Japan Society for the promotion of ScienceWork in part supported by Grant-in Aid for Scientific Research (B) No. 15340012, Japan Society for the promotion of Science     

Non-ergodicity of Two Particles Interacting via a Smooth Potential

We examine two point particles interacting via a smooth Lennard-Jones-type potential of finite range on a two-dimensional torus. We find situations under which this system contains a stable, elliptic periodic orbit and hence is not ergodic. This result is in contrast to the case of hard spheres interacting via inelastic collision, which are always ergodic for two particles, are conjectured to be ergodic for arbitrarily many particles, and can never contain elliptic periodic orbits.     

Hierarchy of the Selberg Zeta Functions

We introduce a Selberg type zeta function of two variables which interpolates several higher Selberg zeta functions. The analytic continuation, the functional equation and the determinant expression of this function via the Laplacian on a Riemann surface are obtained.Mathematics Subject Classifications (2000). Primary 11M36, Secondary 33B15     

Analytic Surgery of the Zeta Function

In this paper we study the asymptotic behavior (in the sense of meromorphic functions) of the zeta function of a Laplace-type operator on a closed manifold when the underlying manifold is stretched in the direction normal to a dividing hypersurface, separating the manifold into two manifolds with infinite cylindrical ends. We also study the related problem on a manifold with boundary as the manifold is stretched in the direction normal to its boundary, forming a manifold with an infinite cylindrical end. Such singular deformations fall under the category of “analytic surgery”, developed originally by Hassell (Comm Anal Geom 6:255–289, 1998), Hassell et al. (Comm Anal Geom 3:115–222, 1995) and Mazzeo and Melrose (Geom Funct Anal 5:14–75, 1995) in the context of eta invariants and determinants.     

Transportation of Two Coupled Particles in an Asymmetric Saw-Tooth Potential

Based on a simple model,we theoretically show the transport behaviors of two harmonically coupled Brownian particles in an asymmetric saw-tooth potential with two slopes.The coupled particles are subject to stochastic fluctuations.It is found that when the equilibrium distance of the coupled particles is between the two slopes of the potential,the transport direction of the coupled particles will be reversed with a certain harmonic coupling strength.This current reversal can be easily understood with the near rigid approximation,where the two coupled particles can be regarded as a single particle in an effective potential.Compared with the original saw-tooth potential,the asymmetry of the effective potential could be reversed when the equilibrium distance is between the two slopes of the original potential,which results in the current reversal.     

星载电子设备浪涌电流抑制以及浪涌电流的测试方法

介绍了一种可用于星载开关电源的浪涌电流抑制电路;该电路在设备供电正线上串连P沟道MOSFET管,其栅源电压受专门设计的RC网络控制;通过调节外围的阻容器件改变栅源电压的上升速率,就可以实现浪涌电流抑制;试验结果表明,该电路可以将启动电流抑制在额定输入电流的1.5倍,或不大于2 A,且持续时间不大于5 ms,上升斜率不大于10⁶A/s;该电路已经被广泛应用于各类星载设备中,设备运行稳定可靠;同时对星载设备浪涌电流的形成原理以及测试方法进行了介绍。     

The Influence of Magnetic Field on Electrokinetic Potential of Colloidal Particles

Russian Physics Journal - The influence of a magnetic field on the electrokinetic potential of colloidal particles in a water flow oversaturated with deposited salts is reported. For the first...