利用演示 讲好电容器

电容器是电气设备中的重要元件之一,它在电子技术和电工技术中有着重要的应用.它的主要参数是容量、耐压及误差等级,它的导电特性是通交流电隔直流电.要使学生能理解这些内容,仅凭老师的讲述是不够的,因此要充分利用演示来讲好电容器.1　用演示引入新课讲课开始时,让学生观察课     

电容器串、并联的演示实验

在"电容器串、并联"教学中,由于缺少仪器,教师只在黑板上进行讲解,学生死记硬背.概念抽象,难以理解.至于电容器极板上电荷积累多少,电容的多少,极板间的距离的大小,极板面积的大小,又看不见,摸不着,只能靠抽象的记忆.学生学得费劲.为此,我分别采用了音乐集成电路和小灯泡在同一块示教板上进行演示实验教学,充分发挥学生的视觉与听觉的作用,间接地衡量出电容器极板上积累电荷的多少,增强了学生的感性认识,提高了教学效果.     

平行板电容器演示实验装置的改进

介绍一种具有干燥、照明和充电系统的演示实验装置，该装置使平行板电容器在演示时能保持所带电荷基本不变。     

关于电容器的一组演示实验

在高中物理电容器的教学中,我们设计并安排了一组用大型示教万用电表组装的电容器演示实验。该实验取材容易、效果明显,能使学生加深对电容概念和物理意义的理解,增强对电容器串、并联时总电容改变的感性认识。一、演示装置装置如图所示。G、V表是目前学校中常用的大型示教万用电表(苏州电表厂出     

就地取材 做好演示实验

演示实验的内容和方法有很大灵活性,在充分发挥现有仪器演示的前提下,还应就地取材,设计与制作一些新的演示实验.用简单的器材做实验使学生感受到物理就在自己身边,物理学并不神秘,从而调动学生的积极性,主动性,养成实验习惯,培养实验技能,发展创造精神,现举几例:1　演示静摩擦     

怎样做好静电演示实验

静电学是电学教学的开始，许多电学的基本概念需要从这里建立：由于静电学的内容比较抽象，很需要我们做一些直观的演示。但是，有些实验，有时却不能很好地演示出来，例如玻璃棒不能很好地带电，起电机不能起电，仪器上保持不住所带的电荷等等，产生这些现象的原因主要是由于静电实验有一个共同的特点，就是“高电压，微电荷”。     

“平行板电容器的电容”演示实验探讨

分析了“平行板电容器的电容”演示实验中与静电计指针偏转变化量有关的因素。     

加强课堂演示实验提高课堂教学效果

课堂演示实验对于说明物理现象,讲清物理原理具有重要作用.目前中学物理教师越来越重视课堂的演示实验,其目的在于使学生对物理现象有清晰的了解,启发思维活动,提高学习兴趣.教育家叶圣陶说"学习一门学科,兴趣是非常重要的,因为它是学习动机诸因素中最活跃、最直接的因素."因此,我们应尽可能地多做一些演示实验.然而,如果单纯依靠现成的仪器是远远满足不了教学需要的.为此,我们自制或改进了演示仪器,在制作教具和设计演示实验时,要做到以下几方面.     

磁性液体磁悬浮原理演示实验研究

基于磁性液体的Bernoulli方程推导了磁性液体中非磁性物体所受的磁悬浮力,通过演示实验研究了2种磁性液体对不同密度非磁性物体的磁悬浮情况．磁性液体中非磁性物体所受的磁悬浮力受磁性液体的磁化率、磁场强度、磁场梯度的影响．相同条件下,随磁场强度和磁场梯度增强,M FP-1磁性液体分别在不同电流时将6种非磁性双锥体浮起,当电流达到3．00 A时,还出现了Rosensweig尖峰;MFP-2磁性液体的磁化率小于MFP-1磁性液体,仅浮起了聚氟乙烯、玻璃、铝双锥体．随着电流增大,中心磁场梯度较强,边缘磁场梯度较弱,出现非磁性双锥体向侧壁移动现象．     

Potato starch-based activated carbon spheres as electrode material for electrochemical capacitor

Potato starch-based activated carbon spheres (PACS) were prepared from potato starch by stabilization, carbonization followed by activation with KOH. The obtained PACS are hollow and retain the original morphology of potato starch with decrease in size, as shown by scanning electron microscopy. Modification of textural properties of the PACS was achieved by varying the carbonization temperature and the ratio of KOH/PCS. The results of N₂ adsorption isotherms indicate that the samples prepared are mainly microporous. The electrochemical behaviors of the hollow PACS were studied by galvanostatic charge-discharge, cyclic voltammetry, and impedance spectroscopy. The results indicate that high specific capacitance of 335 F/g is obtained at current density 50 mA/g for PACS with specific surface area 2342 m²/g. Only a slight decrease in capacitance, to 314 F/g, was observed when the current density increases to 1000 mA/g, indicating a stable electrochemical property.     

利用磁钢与铝质硬币演示楞次定律

利用磁钢和硬币设计了操作简易的磁学演示实验,通过磁钢对铝镁合金制成的硬币的作用力的研究,有助于学生理解楞次定律.     

Performance evaluation of polyacrylamide/silver composite as electrode material in electrochemical capacitor

In this research, polyacrylamide/Ag composite is synthesized and used as an electrode in an electrochemical capacitor (EC). The characterization of the composite is performed by X-ray diffraction, scanning electron microscopy, and cyclic voltammetry methods. The electrochemical characterization is conducted in an electrolytic solution of KOH and an electrolytic solution of Na₂SO₄. The capacitance of the polyacrylamide/Ag composite is associated mainly with the reduction/oxidation of Ag. The specific capacitance of the EC using the KOH electrolyte is 950 Fg^?1, which is better than the capacitance in the Na₂SO₄ electrolyte. This behavior is explained by the respective physical characteristics of the two electrolytes.     

热声致冷效应演示实验

基于热声致冷原理,利用自制的热声堆,采用常见的材料和仪器,设计了扬声器驱动热声致冷实验演示装置.以空气作工质,在无冷却措施的情况下,系统运行200 s后,实现了13℃的降温及25℃的温跨.     

气体栓塞演示实验

利用自制实验装置直观地演示了水在细管中流动，若有气泡存在时产生的气体栓现象。     

Improved asymmetric electrochemical capacitor using Zn-Co co-doped Ni(OH)2 positive electrode material

The performance of Ni-foam pasted Ni(OH)₂ prepared from co-precipitated Ni(OH)₂ with Zinc (Zn) and Cobalt (Co) as the positive electrode active material of an asymmetric electrochemical capacitor (EC) is studied for the enhancement of the capacitor’s specific energy and power densities. A co-precipitated Ni(OH)₂/activated carbon (AC) composite material and AC were used as a positive and negative electrode material. The AC in the positive electrode is used as an electrolyte reservoir to reduce ionic diffusion resistance regardless of charge/discharge current density. In addition, the simultaneous presence of Zn and Co ions in the Ni(OH)₂ layer improves the efficiency of the active material and reduces the resistance of the unit cell. It was observed that through the effects of the additives in the positive electrode, the asymmetric EC exhibits a high energy density with 35.7 Wh/kg, based on the active material. Furthermore, the energy density decreasing behavior at a high discharge current density was retarded. PACS 81.20.Ev; 73.40.Mr; 66.30.Pa; 66.30.Dn     

半导体制冷演示实验

研制了可用于物理教学演示的半导体制冷演示仪，半导体制冷器是纯固体制冷源，既能制冷又能制热，体积小，重量轻，使用方便，无污染，有广泛的应用前景，本仪器着重演示半导体制冷的优点。     

声波干涉演示实验的探讨

从波的叠加原理和波的干涉条件出发对纵波的干涉问题进行了分析，在此基础上对声波干涉实验的关键、方法及注意事项做了讨论。     

3D偏振演示实验

剖析了3D立体效果的形成原理,设计了3D演示实验装置.通过光偏振技术、透镜成像规律以及视觉暂留现象的运用,演示了3D立体效果形成过程.