关于“声波干涉”的演示实验

全日制十年高中物理上册,第八章机械振动和机械波中,在讲述了“波的干涉”后,得到“一切波都能发生干涉。干涉是波特有的现象。”的重要结论。这个结论说明,干涉是波特有的现象,有无干涉现象是判定是否是波动的重要标志。一般在教学中仅做水波干涉的演示实验。通过一个实验要得到这个重要结论,学     

几个课堂演示实验的小改进

1波(机械波)的干涉实验.旧式的波的干涉演示实验仪，用水作为介质，相间的加强区域和减弱区域在振子附近还能看出一些，但稍远一些此实验现象就不明显了．新式的波的干涉实验仪通过镜像放大，效果明显，但发波槽内产生的两列波很不明显，会产生似事先设计好的多媒体演示的感觉．     

演示实验改进二则

演示实验改进二则莫滨（南京市红光中学，２１００１２）水波波源的改进中学物理教学中，利用水波演示波的性质的装置一般都不太理想．波源的间距一般不可调，振幅和频率也不可调，尤其是不能演示不同频率、不同振幅的两个或多个波并存的实验．本文介绍一种简便易行的发波...     

基于声振动的机械波干涉与衍射实验

应用手机Frequency Sound Generator软件提供单频率声波,通过音响将声波振动放大,再借助水波,将干涉与衍射现象可视化,再通过改变相关变量,对机械波干涉的条件进行验证.     

用旋转三角形法判定横波的有关问题

横波在介质中传播时，判定波的传播方向或质点的振动方向，是机械波教学中的一个难点．在教学中如引导学生使用旋转三角形法，能直观、准确、迅速地得到判定，较好地解决了这个教学难点．１旋转三角形判定方法机械波是机械振动在介质中的传播过程．根据振动在介质中的传播...     

水波折射实验的解释

新教材中“波的反射和折射”一节中，关于水波折射实验，同学们难以理解．本文就此作粗浅的解释．     

基于光学投影的智能化水波演示仪

利用频闪光的水波投影设计制作了智能化水波演示装置,增强了水波的各种典型现象的演示效果,利用单片机使波动现象可控可调、持续稳定.使用该装置测量了表面张力波的波速与表面活性剂的关系、波速与波长的关系.     

向列液晶中的指向波研究

本文介绍了一种新的机械波──向列液晶中的指向波的观察方法，它的机理和科学价值，国内外有关研究的评述，最近的研究进展以及尚待进一步研究的问题．     

国外学生对机械波理解的研究

通过对国外物理教育工作者关于学生对机械波理解的研究的介绍，概述在这些研究中所观察到的学生的困难，包括学生在波的传播（包括绳波和声波）、波的数学表述、波的叠加上的具体困难，了解学生对机械波基本概念的掌握情况，对我国的物理教学有一定的借鉴作用。     

多普勒效应及其应用

生活中会有这样的经验：火车急速离去时,汽笛声调会低沉下去;而迎面驶来,声调则变高,这种现象物理上称之为多普勒效应,它是波动现象特有的规律． 简言之,多普勒效应可以这样表述：当波源和观察者存在相对运动时,观察者接收到的波的频率会偏离波动本来的频率,相向运动,频率就升高;相背运动,频率则降低,而且相对运动速度越大,这种频率偏移也越大,电磁波,机械波都会产生多普勒效应,下面是准确的表示公式． 对于机械波,设波动的传播速度为ｕ,波动的固有频率为ｆ．当波源以速度ｖ相对观察者运动时,则接收者接收到波的频率ｆ会…     

Wave Mechanics or Wave Statistical Mechanics

By comparison between equations of motion of geometrical optics and that of classical statistical mechanics, this paper finds that there should be an analogy between geometrical optics and classical statistical mechanics instead of geometrical mechanics and classical mechanics. Furthermore, by comparison between the classical limit of quantum mechanics and classical statistical mechanics, it finds that classical limit of quantum mechanics is classical statistical mechanics not classical mechanics, hence it demonstrates that quantum mechanics is a natural generalization of classical statistical mechanics instead of classical mechanics. Thence quantum mechanics in its true appearance is a wave statistical mechanics instead of a wave mechanics.     

Constrained Wave Equations and Wave Maps

In this paper we establish that wave maps can be obtained by a penalization method if the initial data is well prepared. When the data is not well prepared, we prove that the solution of the penalized equation converges weakly to the solution of the system of coupled equations obtained in [11] by a multi-scale formal analysis. In particular, the interaction between the rapid normal oscillations and the tangential motions creates a new term in the limit system whose well-posedness is proved by using the Nash-Moser Implicit Function Theorem. The first author is funded in part by NSF DMS 0203485.The second author is funded in part by NSF DMS 0101969.     

Wave Mechanics or Wave Statistical Mechanics

By comparison between equations of motion of geometrical optics and that of classical statistical mechanics, this paper finds that there should be an analogy between geometrical optics and classical statistical mechanics instead of geometrical mechanics and classical mechanics. Furthermore, by comparison between the classical limit of quantum mechanics and classical statistical mechanics, it finds that classical limit of quantum mechanics is classical statistical mechanics not classical mechanics, hence it demonstrates that quantum mechanics is a natural generalization of classical statistical mechanics instead of classical mechanics. Thence quantum mechanics in its true appearance is a wave statistical mechanics instead of a wave mechanics.     

关于热声压缩机原理的讨论

回顾了驻波、行波热声机械的发展历史 ,分析了行波与驻波热声压缩机的优缺点。介绍行波驻波混合型热声压缩机的工作原理及结构 ,指出了今后研究的重点和方向。     

Study of Novel Slow Wave Circuit for Miniaturized Millimeter Wave Helical Traveling Wave Tube

Two kinds of novel helical slow wave circuit, supported by Chemical Vapor Deposition (CVD) diamond, are presented. They are applying in miniaturized millimeter wave helical traveling wave tube. Cold test characteristic of these circuits are simulated by MAFIA code. Higher performances are achieved with smaller size, compared with conventional circuit supported by BeO rods. The nonlinear analysis is implemented by Beam and Wave Interaction (BWI) module, which is a part of TWTCAD Integrated Framework. Results have been found to be consistent with the expectation. It should be wider apply in microwave and millimeter wave vacuum electronic devices.     

Wave Relations

The wave equation (free boson) problem is studied from the viewpoint of the relations on the symplectic manifolds associated to the boundary induced by solutions. Unexpectedly, there is still something to say about this simple, well-studied problem. In particular, boundaries which do not allow for a meaningful Hamiltonian evolution are not problematic from the viewpoint of relations. In the two-dimensional Minkowski case, these relations are shown to be Lagrangian. This result is then extended to a wide class of metrics and is conjectured to be true also in higher dimensions for nice enough metrics. A counterexample where the relation is not Lagrangian is provided by the Misner space.     

光纤中声波导布里渊散射声波对斯托克斯波的影响

利用全矢量有限元法模拟了单模光纤中声波导布里渊散射R0,m和TR2,m声波模式对斯托克斯波增益、相位调制和双折射的影响.研究结果表明:当布里渊频移与R0,8和TR2,10声波频率相同时,斯托克斯波的增益最大,且增益随泵浦功率的增大而增大;R0,1、TR2,1、TR2,5、TR2,7和TR2,10声波模式对斯托克斯波相位调制较大,且相位调制随泵浦功率的增大呈线性增大,其中TR2,m模对斯托克斯波相位调制比R0,m模大;TR2,1、TR2,5、TR2,7、TR2,10声波模式对斯托克斯波产生较为明显的附加双折射,且附加双折射程度随着泵浦功率的增加呈线性增大.     

Solitary Wave and Wave Front as Viewed From Curvature

The solitary wave and wave front are two important behaviors of nonlinear evolution equations. Geometrically, solitary wave and wave front are all plane curve. In this paper, they can be represented in terms of curvature c(s), which varies with arc length s. For solitary wave when s → ±∞, then its curvature c(s) approaches zero, and when s=0, the curvature c(s) reaches its maximum. For wave front, when s → ±∞, then its curvature c(s) approaches zero, and when s=0, the curvature c(s) is still zero, but c'(s) ≠ 0. That is, s=0 is a turning point. When c(s) is given, the variance at some point (x,y) in stream line with arc length s satisfies a 2-order linear variable-coefficient ordinary differential equation. From this equation, it can be determined qualitatively whether the given curvature is a solitary wave or wave front.