Calculation of the Specific Heats for the Ⅱ—Ⅲ and Ⅱ—Ⅳ Phase transitions in NH4I

This study gives our calculation for the specific heats CVI due to an Ising model using the observed Cp data for the Ⅱ-Ⅲ and Ⅱ-VI phase transitions in NH4I.By fitting to the CP data we determine the values of the critical exponent for the pressure of 0.14GPa(Ⅱ-Ⅲ phase transition)and for the pressures of 0.75,1.35and 1.97 GPa (II-IV phase transition)in NH4I.Our exponent values values are close to the predicted values of the specific heat in a three-dimensional Ising model.Our calculated CVI are in good agreement with the experimental CP for NH4I in most cases.     

Numerical Calculation and Analysis of Track Etching Process

Heavy ion irradiated polymers can be chemically etched to form track membrane with pores in the micro and sub-micro ranges. It has been reported that pore growth during etching can be related to track structures. A latent track has a track core inside and a track halo surrounding the track core. By single track etching it is observed that etching in the track core is much faster than in the track halo where the etching rate is even lower tlian that of bulk material. For multi-track etching, no such stages can be seen by the conductance measurements.     

Elimination of Spiral Waves and Competition between Travelling Wave Impulses and Spiral Waves

The interaction between travelling wave impulses and spiral waves is studied and the results of their competition are related to the exciting period. From the results, it is known that the formation and development of spiral waves in cardiac tissue depend on the period by which the travelling wave impulses are excited. A method is proposed to eliminate spiral waves, which is easily operated.     

例说“特殊”情形的特殊价值

存在于数学知识中的“特殊”情形,例如数学知识中一些特殊的存在形式、特殊的表达方式,某些定理或性质存在的一些特殊条件以及解决问题过程中的一些特殊方法等等,在学生的数学学习中都起到了重要的教育作用,不少“特殊”甚至还是理解数学知识,乃至最终解决问题的关键所在.1. 数学认识过程的切入点我们可以看到,在数学学习中,一个概念的产生、某一规律的形成,经常是从一些特殊的情形开始,通过分析、归纳、猜想与演绎等各种方法得到完成的,这是数学重要的思想方法———归纳推理,著名数学家高斯就曾说过,他的许多结论都是依赖归纳法而发现…     

《电子技术基础》课程教学的几点思考

《电子技术基础》是学好其他专业课程的基础,它研究电子元器件和电子电路在各种领域的应用,它的发展水平直接影响着各行各业的发展,因此,应帮助学生学好本课程．1联系实际激发学生学习的主动性兴趣是学习的动力,因此在学习之初就必须激发学生的学习兴趣,消除厌学畏难的心理．如在绪论课,给学生介绍日常生活息息相关的电子产品,如电视机、手机、DVD等,同时介绍电子技术在自动控制中的重要性,让学生了解其实用性,激发学习兴趣．再如,在     

谈山脉隆起的极限高度

自从2005年我国地质部门发布了对珠穆郎玛峰的最新测量高度为8844.43米之后,在一些期刊上相继见到有关于从地质力学角度讨论山到底可能"长"到多高的文章,并有断言:9000米是山的极限高度.笔者读后对其核心论述初觉不妥,既而经查阅资料后再研究,形成了颇不同的观点.     

ROMBERG方法的改进

本文研究了全部根构成一个等比数列的多项式的性质，并将所得的结果用到数值积分的Ｒｏｍｂｅｒｇ方法＾「１」，得到了相应遥改进。     

特殊化方法的教育教学功能

所谓特殊化方法 ,就是从问题的特性入手 ,考察合乎条件的特殊情形 (如特殊值、特例、特殊位置及特殊图形 ) ,从中探索、归纳出解决问题的方法和思路的思维方法 .以往 ,我们对特殊化方法的教学 ,较多的是把它当作一种对付选择题和填空题的有效手段或特殊技巧看待 ,而对于其深层次的教学功能 ,挖掘得不多 .然而 ,在 2 0 0 0年全国高考数学试卷中 ,无论是选择题、填空题的处理 ,还是综合性大题的解答 ,特殊化方法都发挥着令人耳目一新的作用 .所以 ,鉴于当前高考对数学思想和方法的考查更加明确、更加成熟 ,笔者认为很有必要挖掘这一方法的教育…     

sl玻色子体系在U(2l+1)O(2l+2)过渡区的严格解

利用无穷维李代数方法得到了相互作用sl玻色子体系在U( 2l+ 1 ) O( 2l+ 2 )过渡区的能谱和波函数的严格解 .给出了该系统Bethe假定方程的数值解法 .     

Sound Field Calculations of Elliptical Pistons by the Superposition of Two—Dimensional Gaussian Beams

We present an alternative approach to calculate the sound field of ultrasonic transducers.The distribution function of sources is expanded into the superposition of a series of two-dimensional Gaussian functions.The corresponding radiated sound field is expressed as the superposition of these two-dimensional Gaussian beams and is then reduced to the computation of these simple functions.This treatment does not require the condition that the shape of the source is of circular axial symmetry.A numerical example is presented for the uniform elliptical piston transducer and this is in good agreement with the results given by complicated computation.