演示物体微小形变的简易装置

高一物理(甲种本)课本14页,图1—10所示是演示微小形变的装置,这一装置是利用光在均匀媒质中的直线传播和平面镜组对光线的两次反射即“光杠杆的放大作用”原理制成的。用这套装置进行实验操作需要局部遮光的房间或暗室,平行光源等器材,使用起来比较麻烦。我们设计了一种操作简便的实验装置,现介绍如下。一、实验器材和组装 1.器材垫木两块,长木板(80×9.5     

物体做曲线运动时瞬时速度方向的演示实验

曲线运动第一节有两个重点：一是曲线运动的条件；二是曲线运动的瞬时速度方向．对于理论的落实，往往采用实验进行验证．下面是笔者对物体做曲线运动时瞬时速度方向如何确定所设计的两个演示实验．     

利用无线DIS创新演示固体微小形变

利用无线DIS实验平台为演示固体微小形变提供新思路,演示结果明显、直观,有效凸显现代信息技术与物理教学的深度融合.     

教学实验与演示仪器信息

湘潭大学物理系研制生产一种弧立波仪是采用微机技术，可以正弦、三角形电振动驱动液槽用来产生双曲正割波形，组结波形非传播弧立波的实验仪器，可用于开设理代物理实验或演示实验，进行对弧立波形成条件、弧波相互作用、弧波对物体的相互作用、液体特性对弧波的影响等实验研究。     

高中物理演示实验教学改革初探

物理学是一门以观察和实验为基础的科学．课堂演示实验是中学物理实验教学的重要组成部分，它不仅是建立物理概念、理解和掌握物理知识和规律不可缺少的环节，还能培养学生的观察能力、思维能力、探索精神以及良好的学习方法，同时演示实验在培养学生的物理兴趣、活跃课堂气氛等方面都发挥了巨大作用。     

将建构主义思想引入物理演示实验教学

物理演示实验可以将抽象的概念形象化，使物理规律直观化．通过演示实验，将那些很难想象和理解的物理规律多次重复地展现在学生眼前，使物理规律得到反复的实验验证，从而让学生体验、感受到物理学理论、概念、规律的深刻含义，加深和拓展对物理内容的理解，了解其应用．这种区别于讲课、习题课和普通物理实验的教学方式，对提高学生的科学技术素质，培养学生观察能力、手脑并用能力、理论联系实际能力等方面，都起着无可替代的作用．按照国家大学物理教学指导委员会下发的最新《大学物理教学大纲》的要求，大学物理教学总学时中20％的学时应在演示实验室中完成．也就是说，物理演示实验应该从单一的传统的课堂辅助教学形式，转化、发展为有利于基础科学教育的演示实验课。     

频闪技术及物理演示实验

早在1964年电子闪光摄影技术就被美国哈罗德·艾杰顿发明应用。现在国内频闪仪器也开始生产，近三年来我们物理演示数学中也采用该技术以显示动态变化的物理过程．引导学生仔细观察物体运动规律，得到了很好的效果。     

巧用杠杆原理,演示微小变化

1 利用二次放大装置，演示金属的热胀冷缩现象。金属的热胀冷缩现象，人眼难以清楚地观察到．若设计一个如图1所示的实验装置，则可显著地提高演示效果，激发学生兴趣，培养学生创新意识．     

测定物体长度微小变化量的实验装置

测定物体长度微小变化量的实验装置李东平，戴玉萍（吉林职业师范学院长春１３００５２）１．引言假定长为Ｌ，截面积为Ｓ的均匀金属丝，在受到沿长度方向的外力Ｆ的作用下伸长δＬ，根据胡克定律，在弹性限度内该金属的杨氏模量为如果某一金属棒的长度为Ｌ０，由于温度改...     

Effects of Slight Plastic Deformation on Magnetic Properties and Giant Magnetoimpedance of FeCoCrSiB Amorphous Ribbons

Slight plastic deformation of 0 to 1% by cold rolling is proposed as a treatment which may modify the responses of magnetoimpedance （MI） sensor with an amorphous ribbon used as a sensitive element. The dependence of the magnetic properties of melt spun Fe3Co67Cr3Si15B12 amorphous ribbons and their MI responses in the initial state and after slight plastic deformation on the value of the deformation were comparatively analysed. The shape of the hysteresis loops shows a clear correlation with the value of the deformation. The variations of the total impedance, the real and the imaginary components, are measured for the current intensity of 1.S mA for the frequency of lO MHz. Slight plastic deformation affects both real and imaginary components and allows a control of the shape of the MI curves in a small field in a range usually used in biomedical applications. The proposed deformation treatments can be useful for the construction of the MI sensitive elements with a new type of the responses.     

Small Deformation Measurements of Diffuse Objects: Phase Stepping by Frequency Drift of a He-Ne Laser

We describe a simple phase-stepping speckle interferometer with large path difference, in which phase modulation is achieved by thermal frequency drift of the He-Ne light source. This system is easy to set up, requires no specialised components, is immune from the effects of piezo actuator hysteresis, and is capable of producing phase maps in which the noise is less than 1/20λ.Presented at 1996 International Workshop on Interferometry (IWI ‘96), August 27-29, Saitama, Japan.     

Slight disorder effects in two dimensional photonic crystal structures

In the actual manufacturing process of photonic crystal structure, unavoidable error can generate slight disorder which may influence the performance of photonic crystal based device. In this work, randomly distributional disorders are applied to the air holes in the photonic crystal structure. Based on this, we investigate the influence of the slight disorder on the photonic crystal band structure and the performance of photonic crystal based devices (waveguide and slab cavity). The studies indicate that the slight disorder provides small influence on the band structure of the photonic crystal. But, the random disorder in photonic crystal waveguide may increase transmission loss obviously when the wavelength of the light and the distribution of disorder break the balance of multiple interferences. Also, the slight disorder can reduce the Q factor of the photonic crystal cavity at a certain degree. The studies may provide some useful guides for further photonic crystal device research.     

三光路结构的调频连续波重采样测距方法

调频重采样是一种绝对测距技术。这种方法采用的光源波长随时间变化,形成一束宽光谱激光。激光在各时刻的波长通过辅助干涉装置进行测量,并对其中频率间隔相同的部分进行重采样,使调频测距系统具有较大的线性光谱带宽,较高的分辨率及精度。在实际测量过程中,测量装置本身及待测物都容易受到振动的影响,导致待测距离及辅助光纤长度发生变化,引入测距误差。针对这个问题,分析了振动对重采样测量结果产生的误差:(1)待测物的移动引入一个多普勒频移分量;(2)辅助光纤的振动使重采样频率也发生变化。为了弥补这两种误差,提出了一种三光路结构的补偿方法,在辅助光路中,使用一种光路结构简单小巧,且测量速度更快的全光纤马赫泽德干涉仪等效代替光谱仪,实时的监测信号光的瞬时频率。在测量光部分,在测量光路中引入两个部分反射镜产生两路补偿光信号,并通过FFT算法产生频谱。频谱的三个峰值分别与三路信号相对应。通过测量信号与其中一路补偿信号的峰值相减即可补偿多普勒误差,通过两路补偿信号的频率差与相对距离的比值即可得出实际的辅助光纤长度。实验证明,传统的重采样测距方法精度为23.6μm,三光路测距方法的精度可达到11μm,可见这种方法能够对系统的振动误差进行有效补偿。     

The Picard Groupoid in Deformation Quantization

In this Letter we give an overview on recent developments in representation theory of star product algebras. In particular, we relate the *-representation theory of *-algebras over rings C = R(i) with an ordered ring R and i²=?1 to the *-representation theory of *-algebras over and point out some properties of the Picard groupoid corresponding to the notion of strong Morita equivalence. Some Morita invariants are interpreted as arising from actions of this groupoid     

The Picard Groupoid in Deformation Quantization

In this Letter we give an overview on recent developments in representation theory of star product algebras. In particular, we relate the *-representation theory of *-algebras over rings C = R(i) with an ordered ring R and i²=–1 to the *-representation theory of *-algebras over and point out some properties of the Picard groupoid corresponding to the notion of strong Morita equivalence. Some Morita invariants are interpreted as arising from actions of this groupoid     

声音通过空气传播的实验演示

初二物理教材在演示声音通过空气传播的实验中采用了一对共振音叉装置(图1)．“敲响右边的音叉，左边完全相同的音叉也会发声，并且把泡沫塑料球弹起．”实践表明效果不是很理想，因为共振音叉发生共振时振幅甚微，即便是第一排的学生也很难明显听到左边音叉的声音和清楚地看到小球     

The Burst Time Duration in Micropillar Deformation

Plastic flow of single crystal micropillars proceeds through a sequence of intermittent burst slips. The burst time durations are investigated based on an extended theoretical model which incorporates the observed power-law distribution of burst sizes in compression experiments of micropillars. The results show that the burst time durations exhibit a powerlaw behavior with an exponential cutoff, suggesting the same scaling behaviors as the burst sizes. In addition, the predicted scaling exponent is found to converge to a value of -1.6. It is demonstrated that our results are consistent with the experimental data.     

基于运动目标尺寸检测的实时图像处理与显示

运动目标尺寸实时检测与显示是运动图像检测和应用视觉研究领域的一个重要课题,而图像处理则是其核心内容;文章针对采集到的图像进行一系列的处理,最终实时显示图像并获得运动目标的尺寸等信息;首先针对采集图像时电子设备的不稳定性和检测模块的不一致性,进行中值滤波和增益校正同时将处理图像实时显示出来;然后对其整体图像进行分割与二值化、角点检测和边缘拟合处理,获得目标的尺寸信息;最后利用VC++将整体处理图像及尺寸信息显示出来,以便于图像理解和模式识别;实验证明,文章提出的算法、软件的设计很好地滤除不相关的目标,保存感兴趣目标,具有良好的实时性、精确性,能够满足当代工业检测设备中的要求。     

The Integrability of Lie-invariant Geometric Objects Generated by Ideals in the Grassmann Algebra

Abstract

We investigate closed ideals in the Grassmann algebra serving as bases of Lie-invariant geometric objects studied before by E.Cartan. Especially, the E.Cartan theory is enlarged for Lax integrable nonlinear dynamical systems to be treated in the frame work of the Wahlquist Estabrook prolongation structures on jet-manifolds and Cartan-Ehresmann connection theory on fibered spaces. General structure of integrable one-forms augmenting the two-forms associated with a closed ideal in the Grassmann algebra is studied in great detail. An effective Maurer-Cartan one-forms construction is suggested that is very useful for applications. As an example of application the developed Lie-invariant geometric object theory for the Burgers nonlinear dynamical system is considered having given rise to finding an explicit form of the associated Lax type representation.