共查询到20条相似文献,搜索用时 750 毫秒
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The band selectivity of crystal-like structures is evaluated. A high-selectivity electromagnetic crystal is offered and studied. 相似文献
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The main goal of the paper is to give a short review on neutrino electromagnetic properties. In the introductory part of the paper a summary on what we really know about neutrinos is given: we discuss the basics of neutrino mass and mixing as well as the phenomenology of neutrino oscillations. This is important for the following discussion on neutrino electromagnetic properties that starts with a derivation of the neutrino electromagnetic vertex function in the most general form, that follows from the requirement of Lorentz invariance, for both the Dirac and Majorana cases. Then, the problem of the neutrino form factor definition and calculation within gauge models is considered. In particular, we discuss the neutrino electric charge form factor and charge radius, dipole magnetic and electric and anapole form factors. Available experimental constraints on neutrino electromagnetic properties are also discussed, and the recently obtained experimental limits on neutrino magnetic moments are reviewed. The most important neutrino electromagnetic processes involving a direct neutrino coupling with photons (such as neutrino radiative decay, neutrino Cherenkov radiation, spin light of neutrino and plasmon decay into neutrino-antineutrino pair in media) and neutrino resonant spin-flavor precession in a magnetic field are discussed at the end of the paper. 相似文献
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采用了窄带和超宽谱高功率微波源,在微波暗室和开阔试验场地中建立了多个典型波段的微波辐射场;并利用辐射场测量系统,对多种测试样片和屏蔽室模型试验样片的屏蔽效能进行了试验。结果表明:当测试窗样片厚度(屏蔽室模型试验样片壁厚)大于30 mm时,对窄带高功率微波的屏蔽效能可达到80 dB以上,对超宽谱高功率微波的屏蔽效能可达到50 dB以上。该特种电磁材料可广泛应用于三级屏蔽要求的工程中,当周围的电磁环境以窄带微波为主时,可谨慎应用于屏蔽要求较高的防护工程中。 相似文献
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针对半导体器件、电路、电子系统的高功率微波效应,提出了一套全新的多层次多物理场协同计算方法。该算法基于半导体器件的物理结构模型,联立并求解由电磁场、半导体物理和热力学方程构成的多物理场方程组,实现了器件级高功率微波效应的仿真;通过器件多物理场仿真和电路仿真的协同计算完成电路级效应仿真;最后进行电路效应和电磁环境的协同计算,获取由多个电路、外壳封装、孔缝和线缆等组成的电子系统的高功率微波效应数据。介绍了该算法的原理和流程,以商业PIN二极管为例,计算了该器件及组成限幅器电路的温度效应、正向恢复特性、半封闭腔体内空间微波辐射等效应,通过与实验测试的对比验证了算法的正确性,同时对效应现象给出了物理机理解释。 相似文献
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M. I. Faingol'd 《Radiophysics and Quantum Electronics》1979,22(5):364-371
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Marek Demianski 《Foundations of Physics》1986,16(2):187-190
A static, spherically symmetric, and asymptotically flat solution of coupled Einstein-Born-Infeld equations is presented. When the internal mass of the system is zero the resulting space-time is regular and describes static electromagnetic geon. 相似文献
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N. P. Khvorostenko 《Russian Physics Journal》1992,35(3):223-227
A hypothesis for the possibility of longitudinal electromagnetic waves in arbitrary media is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 24–29, March, 1992. 相似文献
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M. Hayakawa 《Radiophysics and Quantum Electronics》1994,37(6):464-467
The terrestrial electromagnetic noise environment in the frequency range from ULF to VLF/ELF is reviewed mainly on the basis of our latest results, and important new findings are described.The University of Electro-Communications, Tokyo, Japan. Published in Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 6, pp. 720–726, June, 1994. 相似文献
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A null-plane current commutator algebra, abstracted from a fermion theory, is shown to satisfy the Pagels condition for finite electromagnetic self-masses of hadrons. 相似文献
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J. J. M. Verbaarschot P. J. Brussaard 《Zeitschrift für Physik A Hadrons and Nuclei》1985,321(1):125-135
In this paper the distribution of electromagnetic transition amplitudes 〈W′∥O∥W〉 is described in terms of fluctuations about a gaussian secular variation (as a function of initial and final energies) according to the Porter-Thomas assumption. Explicit formulas are derived both for the case (i) that∑ w ′¦〈W′∥O∥W〉¦2 is replaced by its local average and (ii) that∑ W ′¦〈W′∥O∥W〉¦2 is treated as a stochastic variable showing a χ d 2 -distribution. The resulting distribution function appears to possess a monomial tail. Comparisons with shell-model results are made. 相似文献
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Lerosey G de Rosny J Tourin A Derode A Montaldo G Fink M 《Physical review letters》2004,92(19):193904
We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-micros electromagnetic pulse at a central frequency of 2.45 GHz in a high-Q cavity. Another antenna records the strongly reverberated signal. The time-reversed wave is built and transmitted back by the same antenna acting now as a time-reversal mirror. The wave is found to converge to its initial source and is compressed in time. The quality of focusing is determined by the frequency bandwidth and the spectral correlations of the field within the cavity. 相似文献
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将一个轻质强磁铁圆片贴在一枚螺钉的钉帽上,使顶尖悬挂于电池正极.再将一根导线的一端连到电池负极,另一端与磁铁侧面形成滑动接触.连成回路后,螺钉与磁铁片将绕自身轴开始旋转,这样就构成了一个最简易的电动机模型.本文讨论了这种电动机的原理,给出了该电动机转子角速度随时间变化规律的理论分析,讨论了相关因素的影响,并给出了实验验证. 相似文献
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A. N. Oraevskii 《Journal of Russian Laser Research》1989,10(2):157-176
Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow. Translated from Preprint No. 232 of the Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow, 1988. 相似文献
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