共查询到20条相似文献,搜索用时 62 毫秒
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弦振动实验装置的改进刘全跃(皖南医学院芜湖241001)一、问题的提出弦振动研究实验是普通物理实验的一个基本内容,通过这个实验可加深对横波的产生、传播以及所形成驻波的理解,并可学会一种测量频率的方法——驻波法,实验中常用的振源是电动音叉;然而传统的弦... 相似文献
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振动弦的“色散”实验研究 总被引:1,自引:1,他引:0
研究了有界弦横向强迫振动时弦上波速的色散现象.实验测量结果表明:由弦的张力和线密度决定的弦上的波速(T/ρ)~1/2不一定是常量,在一定的条件下,弦的波速会随着弦驻波的波长长度(弦长)改变而变化. 相似文献
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一、问题的提出“弦振动的研究”,是普通物理力学实验中的一个基本实验。在杨述武等编著的《普通物理实验这》(力学、热学部分)教材中,根据一年级学生的数理基础,给出了简单的实验原理和计算公式。但该实验中所出现的一些物理现象却反映了更深的物理内涵。如在弦长一定,半波数愈少,则驻波的波腹将愈大(此时音叉对弦的策动并没改变)。再如思考题:在弦的长度、线密度和弦可张力 相似文献
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A. H. Taub 《General Relativity and Gravitation》1979,10(12):1009-1009
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Ugeda MM Fernández-Torre D Brihuega I Pou P Martínez-Galera AJ Pérez R Gómez-Rodríguez JM 《Physical review letters》2011,107(11):116803
Understanding the coupling of graphene with its local environment is critical to be able to integrate it in tomorrow's electronic devices. Here we show how the presence of a metallic substrate affects the properties of an atomically tailored graphene layer. We have deliberately introduced single carbon vacancies on a graphene monolayer grown on a Pt(111) surface and investigated its impact in the electronic, structural, and magnetic properties of the graphene layer. Our low temperature scanning tunneling microscopy studies, complemented by density functional theory, show the existence of a broad electronic resonance above the Fermi energy associated with the vacancies. Vacancy sites become reactive leading to an increase of the coupling between the graphene layer and the metal substrate at these points; this gives rise to a rapid decay of the localized state and the quenching of the magnetic moment associated with carbon vacancies in freestanding graphene layers. 相似文献
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We study the relation between the centro-affine geometry of star-shaped planar curves and the projective geometry of parametrized maps into RP1. We show that projectivization induces a map between differential invariants and a bi-Poisson map between Hamiltonian structures. We also show that a Hamiltonian evolution equation for closed star-shaped planar curves, discovered by Pinkall, has the Schwarzian KdV equation as its projectivization. (For both flows, the curvature evolves by the KdV equation.) Using algebro-geometric methods and the relation of group-based moving frames to AKNS-type representations, we construct examples of closed solutions of Pinkall’s flow associated with periodic finite-gap KdV potentials. 相似文献
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《Surface science》1986,171(1):103-110
Cl2 layers adsorbed on Grafoil have been investigated by X-ray diffraction between 78 and 285 K. Mono- and submonolayers crystallize in a parallelogram lauttce, incommensurate with the (001) graphite surfaces, the molecules oriented almost perpendicular to the surface. The structure is closely related to that of the (001) planes of three-dimensional solid chlorine. For coverages above the monolayer completion bulk crystalization sets in. 相似文献
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In this note we use some of the results of [3] to derive a general duality theorem for the cohomologies of foliated structures on a manifold. The result is applied to the special case of a symplectic manifold M on which the foliation is given by a complex polarization F in the sense of geometric quantization. We obtain, for example, a rigorous proof of the fact that for a smooth function ƒ on M whose Hamiltonian vector field leaves F invariant, the spectrum of the corresponding prequantization operator v(ƒ) coincides with the spectrum of its transpose, under the above duality. This latter result was obtained by Simms in [12] under certain hypotheses. Proofs of the validity of those hypotheses are now available in the literature; cf. [3] and [7]. 相似文献
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Valfells A. Verboncoeur J.P. Lau Y.Y. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(3):529-536
Analyzes the effects of space charge shielding on the steady state of a multipactor discharge on a dielectric. Analytic methods are used to obtain an exact function for the potential in the discharge, assuming a Maxwellian distribution of emitted electrons. An equation for the amount of power deposited on the dielectric by the multipactoring electrons, for a given saturation level, is given. A simple method for obtaining the saturation level, for a given material, is obtained 相似文献
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Kopeikin SM 《Physical review letters》2007,98(22):229001; discussion 229002