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磁场对通电导体有磁场力的作用 ,而电流实际上是运动的电荷 ,由此自然想到磁场是否对运动电荷有作用 .为了检验这个问题 ,我们利用黑白电视机来做一些实验 .打开黑白电视机 ,小心取下显像管 ,让同学们认识电子枪和荧光屏 .电子枪是由阴极和阳极组成的 ,通电可以发射电子 ,电子束打到荧光屏上某点 ,该点发光 .拿去磁环和偏转线圈 ,拔掉行扫描电压线和场扫描电压线 .给电视通上电流 ,电子枪被点亮 ,发射电子 ,电子束不受到其它的作用力 ,沿直线打在荧光屏上 ,荧光屏中央出现一个亮点 .取一个U型磁铁 ,让显像管的颈部处于U型磁铁匀强磁场里 ,… 相似文献
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本综述首先较为系统地介绍了近代光子学的一个重要分支——纳米等离子激元学(nanoplasmonics)中有关基础概念的物理、光学背景及推动该学科的演绎发展脉络. 这包括由在平滑界面上的光学表面波(optical surface wave)从物理上导出表面等离子激元(surface plasmon polariton, SPP)的概念, 再由粗糙表面及较大金属颗粒对SPP的影响, 引出线度远小于光波长的纳米金属颗粒与光电磁波的相互作用的结果: 本地表面等离子激元(localized surface plasmon polariton)的存在, 亦即纳米等离子激元学的基础. 在简介了纳米等离子激元学器件系统如何在诸多领域突破了传统光学的束缚, 演绎开辟出了近代光学研究的许多特异的新领域后, 特别关注了近期迅速发展并引起越来越多关注的可调制的纳米等离子激元学(tuneable nanoplasmonics)器件的领域. 液晶材料在光学响应方面特有的可调制特性, 使其在纳米等离子激元学器件的调制中成为一个具有非常实用意义的探索方向. 本综述介绍了这方面研究的最新进展, 并对存在的挑战及可能的发展方向等也进行了相应的探讨. 相似文献
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1为什么有极少数的电视机关机后荧光屏上会有暗斑? 夜晚,打开电视机,在工作一段时间之后,关闭电视机电源及室内的灯光,在黑暗的背景下,有极少数的电视机荧光屏上会出现不规则的暗斑. 相似文献
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自从液晶被发现之后,便有众多的科学家对它展开了兴趣盎然和富有成效的研究,曾有过几十年的兴盛历史.可是,在二战以后,这种研究工作却几乎停止下来.究其原因,主要是人们认为液晶是个无用之物.到了60年代则又出现转机,这是因为人们发现液晶具有灵敏的显示功能,应用它可以制造各种显示器件.现在,由于技术上的需要,液晶研究工作正在全世界迅猛发展.液晶显示与一般显示的主要区别在于:液晶本身不发光,而是利用它在电场作用下产生各种电光效应,以调制环境光,从而达到显示的目的. 相似文献
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从液晶显示到液晶生物膜理论:软凝聚态物理在交叉学科发展中的创新机遇 总被引:1,自引:0,他引:1
世界之交,物理学正在与化学、材料科学、生命科学等相互交叉形成新的学科,凝聚态物理为例,在传统的固体物理以外,最近几年又诞生了一门新学科--软件体物理、或称为复杂流体,液晶 物质凝聚态的重要研究对象,60年代发展起来的液晶显示技术与70年代创立的液晶生物膜理论,充分显示了软凝聚态物理在21世纪的信息与生命科学时代将发挥重要的基础学科作用,是科学技术富于创新发展的领域。 相似文献
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本文介绍了交流薄膜电致发光高清晰度平板电视和显示器的发展历史,根据ACTFEL器件的特殊性能,分析了其应用于高清晰度平板电视的优势,综述了ACTFEL平板电视的彩色化进展和主要方案。 相似文献
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简述了脉冲管制冷机研究现状和存在的问题 ,介绍了低温中心建立的脉冲管制冷机动态参数实验系统。通过对一典型脉冲管制冷机的动态参数的实验数据测量 ,分析了动态压力和质量流量之间的振幅和相位关系 ,首次在实验中发现了存在于脉冲管制冷机内部的直流现象 (DC-Flow)。指出该直流分量是脉冲管制冷机的一种损失 ,揭示了多路旁通进气方式可减小直流损失 ,提高脉冲管制冷机的效率。并从理论上分析了产生直流现象的根本原因 ,给出了直流分量的具体数值和大小。 相似文献
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John Scupham 《Contemporary Physics》2013,54(3):236-241
Television can be used in the service of informal education, or more formally in schools and colleges. This article deals with the educational problems raised by the latter use. Those problems will only be solved when scientists in general take the medium seriously enough to master its techniques of communication and to co-operate in assessing its impact. Its powers and limitations, which are not basically different from those of film, can already be discerned in broad outline. The ways in which it is being developed in different countries depend not only on the qualities of the medium but on their differing educational systems. In this country the emphasis is on the help which television can give to the teacher at all levels rather than on the possibility of replacing him. The nature of that help must be determined in the light of educational purposes. 相似文献
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Recently the block-diagonalization of Dirac-operators was investigated from a mathematical point of view in the one-particle
case [14]. We extend this result to the N-particle case. This leads to a perturbative realization of the Furry picture in the N-particle two-spinor space.
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Madelung showed how the complex Schrödinger equation can be rewritten in terms of two real equations, one for the phase and one for the amplitude of the complex wave function, where both equations are not independent of each other, but coupled. Although these equations formally look like classical hydrodynamic equations, they contain all the information about the quantum system. Concerning the quantum mechanical uncertainties of position and momentum, however, this is not so obvious at first sight. We show how these uncertainties are related to the phase and amplitude of the wave function in position and momentum space and, particularly, that the contribution from the phase essentially depends on the position–momentum correlations. This will be illustrated explicitly using generalized coherent states as examples. 相似文献
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Hirose A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1978,6(1):21-23
Landau damping factor is obtained from actual physical process based on wave-particle interaction following the treatments of Dawson. 相似文献
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J. J. Rehr 《Foundations of Physics》2003,33(12):1735-1742
The Golden rule expression for x-ray absorption spectra (XAS) is typically calculated within a one-particle (quasiparticle) approximation and generally leads to good agreement between theory and experiment. The fact that a quasiparticle approximation works fairly well is surprising, since it neglects satellite excitations and intrinsic losses due to a suddenly created core-hole. The resolution of this paradox requires physics beyond the independent particle approximation. This is discussed here using an effective Green's function formulation based on a quasi-boson model that takes interference between inelastic losses into account. This approach shows that inelastic excitations such as multi-electron excitations tend to be suppressed, and that the XAS is given by a broadened quasiparticle particle approximation, together with weak satellite structure and edge singularity effects. 相似文献