共查询到20条相似文献,搜索用时 125 毫秒
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超导电力技术具有诸多优势和良好的应用前景,世界范围内已完成多个超导电力装置的研发和示范应用。一根360m/10kA高温超导直流输电电缆(10kA超导电缆)的研制已经完成并成功实现并网示范运行。文中介绍了10kA超导电缆主要结构参数,讨论了超导电缆损耗源,重点分析了10kA超导电缆终端、低温杜瓦管和通电导体的损耗情况,终端电流引线是超导电缆热损耗最主要来源。10kA稳态运行条件下的损耗测试情况表明,低温液氮闭合循环系统满足10kA超导电缆冷却要求,其自身低温损耗为1600W左右,与分析结论基本吻合。 相似文献
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本文利用全电流超导隧道结电子模拟器研究了dc与rf电流激励超导隧道结 .在固定rf激励频率和阻尾的条件下 ,随着rf激励幅度增加 ,初步观察到了系统的周期、次谐波和混沌解的无穷尽序列现象 . 相似文献
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We study a new class of nonlinear cooperative phenomena that occur when light propagates in direct-gap semiconductors. The
nonlinearity here is due to a process, first discussed by A. L. Ivanov, L. V. Keldysh, and V. V. Panashchenko, in which two
excitons are bound into a biexciton by virtue of their Coulomb interaction. For the geometry of a ring cavity, we derive a
system of nonlinear differential equations describing the dynamical evolution of coherent excitons, photons, and biexcitons.
For the time-independent case we arrive at the equation of state of optical bistability theory, and this equation is found
to differ considerably from the equations of state in the two-level atom model and in the exciton region of the spectrum.
We examine the stability of the steady states and determine the switchover times between the optical bistability branches.
We also show that in the unstable sections of the equation of state, nonlinear periodic and chaotic self-pulsations may arise,
with limit cycles and strange attractors being created in the phase space of the system. The scenario for the transition to
the dynamical chaos mode is found. A computer experiment is used to study the dynamic optical bistability. Finally, we discuss
the possibility of detecting these phenomena in experiments.
Zh. éksp. Teor. Fiz. 112, 1778–1790 (November 1997) 相似文献
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The critical state in granular superconductors is studied using two mathematical models: systems of differential equations for the gauge-invariant phase difference and a simplified model that is described by a system of coupled mappings and in many cases is equivalent to the standard models used for studying self-organized criticality. It is shown that the critical state of granular superconductors is self-organized in all cases studied. In addition, it is shown that the models employed are essentially equivalent, i.e., they demonstrate not only the same critical behavior, but they also lead to the same noncritical phenomena. The first demonstration of the existence of self-organized criticality in a system of nonlinear differential equations and its equivalence to self-organized criticality in standard models is given in this paper. 相似文献
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On precise center stable manifold theorems for certain reaction–diffusion and Klein–Gordon equations
We consider positive, radial and exponentially decaying steady state solutions of the general reaction–diffusion and Klein–Gordon type equations and present an explicit construction of infinite-dimensional invariant manifolds in the vicinity of these solutions. The result is a precise stable manifold theorem for the reaction–diffusion equation and a precise center-stable manifold theorem for the Klein–Gordon equation, which include the co-dimension of the manifolds and the decay rates for even perturbations. 相似文献
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In this paper multiple delay feedback control (MDFC) with different
and independent delay times is shown to be an efficient method for
stabilizing fixed points in finite-dimensional dynamical systems.
Whether MDFC can be applied to infinite-dimensional systems has been
an open question. In this paper we find that for infinite-dimensional
systems modelled by delay differential equations, MDFC works well for
stabilizing (unstable) steady states in long-, moderate- and
short-time delay regions, in particular for the hyperchaotic case. 相似文献
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V. I. Ponomarenko M. D. Prokhorov A. S. Karavaev B. P. Bezruchko 《Journal of Experimental and Theoretical Physics》2005,100(3):457-467
Methods for reconstructing a delay differential equation from the time series of an observable quantity are proposed for various classes of time-delay systems. The methods rely on knowledge of the distributions of extrema of the time series of observed oscillations and projection of the infinite-dimensional phase spaces of time-delay systems onto special low-dimensional subspaces. The effectiveness of the proposed methods is demonstrated by reconstructing delay differential equations from their chaotic solutions, including those corrupted by noise, and by constructing models of real time-delay systems from chaotic time series. 相似文献
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Electrodynamic phenomena related to vortices in superconductors have been studied since their prediction by Abrikosov, and seem to hold no fundamental mysteries. However, most of the effects are treated separately, with no guiding principles.We demonstrate that the relativistic vortex worldsheet in spacetime is the object that naturally conveys all electric and magnetic information, for which we obtain simple and concise equations. Breaking Lorentz invariance leads to down-to-earth Abrikosov vortices, and special limits of these equations include for instance dynamic Meissner screening and the AC Josephson relation. On a deeper level, we explore the electrodynamics of two-form sources in the absence of electric monopoles, in which the electromagnetic field strength itself acquires the characteristics of a gauge field. This novel framework leaves room for unexpected surprises. 相似文献
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Heng-Mei Li Shuai Wang Zhen Wang Xue-Fen Xu 《International Journal of Theoretical Physics》2014,53(3):830-836
According to operator-sum representation theory, we have identified infinite-dimensional Kraus operators for describing a thermal channel with self-Kerr interaction after directly solving the corresponding master equation by virtue of thermo entangled state. Then we also prove in detail that Kraus operators hold the normalization. As an example, we exactly calculate the evolving result of a chaotic field in the thermal environment with the Kerr medium and find that the chaotic field evolves into a new chaotic field unaffected by the coupling factor with the Kerr medium. 相似文献
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This is a review article on the boson method in superconductivity. It covers derivations of the basic equations in the boson method and applications of these equations to the magnetic properties of type II superconductors and to the Josephson phenomena. 相似文献