Ляпунов直接方法在液体表面张力不稳定问题中的应用

本文应用连续系统的直接方法对于旋转液体柱,柱形液体环和柱面内外液体膜等各种情形下表面张力不稳定问题作了统一的处理,得到这些情形下旋转运动稳定的充要条件。     

子空间迭代法计算振型导数

本文采用子空间迭代法在计算结构频率和振型的同时计算振型导数．     

摩擦振动停点的一般解

摩擦振动停点的一般解邓桂昌，杭庆平（扬州大学师范学院物理系，扬州２２５００２）１．引言质量为ｍ的物块，被一弹性系数为ｋ的弹簧系住，弹簧的另一端固定，把ｍ从弹簧的原长拉开一段距离ｘ＿０后无初速地放手，让其在摩擦系数为μ的水平面上振动，求最后停点ｘｆ的最...     

高斯型非均匀应力对铁磁薄膜磁化性质的影响

采用Monte-Carlo方法研究了高斯型非均匀应力对的铁磁薄膜磁化性质的影响.结果表明: 与易轴平行的拉应力和与易轴垂直的压应力能够增大系统的矫顽场, 而与易轴平行的压应力和与易轴垂直的拉应力则会减小系统的矫顽场.在矫顽场增大(减小)的同时, 系统还伴随着剩磁及其矩形度的增大(减小).更有意义的是, 在与易轴平行的压应力或与易轴垂直的拉应力作用下, 在应力的集中区域会出现“易轴旋转”的现象. 这种产生“易轴旋转”的应力集中区域的范围强烈地依赖于应力的强度和分布宽度. 关键词： 铁磁薄膜 非均匀应力 Monte-Carlo方法 磁滞回线     

液体燃烧热的测定

文章从燃烧热测定的方法原理,实验操作,数据处理和应用的角度,探讨了液体样品燃烧热测定方法.取一定量的标准试样,置于氧弹中,向氧弹中充入过量的氧气,再将氧弹置于一定量的水中,让试样在氧弹中燃烧,释放的热量被水吸收,准确测定水的升温值,在一定温度下,吸收热量的水以及水中各个器件所构成的量热体系的热容量是一个常数,然后将样品与已知热值且不易挥化的液体混合后一并装入封闭的聚乙烯燃烧杯中,利用得到的仪器热容量,按相同的实验操作方法,利用自编的数据处理系统计算出液体样品的燃烧热.此法准确、简便、实用,用于日常检测工作.     

多束激光球靶耦合中能量沉积的均匀性

采用Skupsky理论作为讨论能量沉积均匀问题的基础。把不均匀性σnms分解为两个因子的乘积：一个因子取决于激光系统的几何配置：另一个因子取决于单束激光形成的能量沉积分布。按照几何光学的光路方程，追踪激光在靶球等离子体中的轨迹，计算激光在光路轨迹上的能量沉积（通过逆韧致吸收机制），求得激光在靶球上能量沉积的空间分布，并在此基础上进行能量沉积的均匀性研究。     

ON THE SPH-DISTRIBUTION CLASS

Following up Neuts‘ idea, the SPH-distribution class associated with bounded Q matrices for infinite Markov chains is defined. The main result in this paper is to characterize the SPH class through the derivatives of the distribution functions. Based on the characterization theorem, closure properties, the expansion, uniform approximation,and the matrix representations of the SPH class are also discussed by the derivatives of the distribution functions at origin.Key words Phase type distribution, absorbing Markov chain, operator theory, SPH- distribution, properties     

牛顿环实验综述

17世纪初,物理学家牛顿在考察肥皂泡及其它薄膜干涉现象时,把一个玻璃三棱镜压在一个曲率已知的透镜上。偶然发现了干涉圆环,并对此进行了实验观测和研究。迄今,牛顿环干涉实验以装置简单、操作方便、物理图象明显等优点在对大中学生进行技能训练的物理实验中得到广泛采用。本文根据自己的实践经验和多年的教学体会,对这一典型实验进行较全面的总结、分析和探讨。     

Detection of a Physical Difference between the CDM Halos in Simulation and in Nature

Numerical simulation is an important tool that is helpful for us to understand the process of structure formation in the universe. However, many simulation results of cold dark matter （CDM） halos on a small scale are inconsistent with observations： the central density profile is too cuspy and there are too many substructures, Here we point out that both the problems may be connected with a hitherto unrecognized bias in the simulated halos. Although CDM halos in nature and in simulation are both virialized systems of collisionless CDM particles, gravitational encounter cannot be neglected in the simulated halos because they contain many fewer particles. We demonstrate this by two numerical experiments, showing that there is a difference on the microcosmic scale between the natural and simulated halos. The simulated halo is more akin to globular clusters where gravitational encounter is known to lead to such drastic phenomena as core collapse. Such an artificial core collapse process appears to link the two problems together in the bottom-up scenario of structure formation in the ACDM universe. The discovery of this bias also has implications on the applicability of the Jeans theorem in galactic dynamics.