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排序方式: 共有294条查询结果,搜索用时 15 毫秒
281.
282.
The optical transmission properties of a one-dimensional Drude model photonic crystal are investigated. The linear wave propagation is studied by the transfer matrix method. Using a delta-function approximation a nonlinear 2-d map is obtained and used to explore the global transmission properties of nonlinear wave propagation in this system. Inclusion of a frequency-dependent refractive index represented by the Drude model results in a considerable modification of the characteristics of the linear and nonlinear wave propagation of the one-dimensional photonic crystal. 相似文献
283.
284.
J.E. Macías-Díaz 《Wave Motion》2011,48(1):13-23
The nonlinear processes of supratransmission and infratransmission are employed here in order to show numerically that binary information may be transmitted into (2 + 1)-dimensional, continuous Frenkel-Kontorova media spatially defined on a square, by perturbing harmonically two adjacent boundaries by means of Neumann conditions. The presence of these nonlinear phenomena is established numerically through a computational method that preserves the positivity of the energy operators, and that consistently approximates the solution of the model, the local energy density, the total energy and its dissipation; the existence of a region of bistability where two regimes coexist (conducting and insulating) is established as a corollary. The transmission of binary information is accomplished by fixing a frequency in the forbidden band-gap of the system, and modulating the amplitude of the signals as the sum of a seed (whose amplitude oscillates sinusoidally between the supratransmission and infratransmission thresholds) and small, positive, constant perturbations associated to nonzero bits. Our simulations show that a reliable transmission of information is indeed feasible. 相似文献
285.
Zhiping Wang 《Journal of luminescence》2011,131(11):2404-2408
The optical bistability and multistability in an Er3+-doped ZrF4-BaF2-LaF3-AlF3-NaF optical fiber inside a ring cavity are investigated. The underlying mechanism shows some new characteristics that other schemes do not have. Thus, it may provide some new possibilities for technological applications in optoelectronics and quantum information science. 相似文献
286.
Manuel Souto Dayana C. Morales Judith Guasch Imma Ratera Concepció Rovira Anna Painelli Jaume Veciana 《Journal of Physical Organic Chemistry》2014,27(6):465-469
A comparative analysis of the physicochemical properties of different donor–acceptor dyads, based on a perchlorotriphenylmethyl radical acceptor subunit linked through a vinylene π‐bridge to ferrocene derivatives (1–3) or a tetrathiafulvalene (4) donor subunit, is presented. Intramolecular electron transfer and charge delocalization of these donor–acceptor dyads are discussed on the basis of data obtained in solution by cyclic voltammetry, UV–Vis near‐infrared, and electron spin resonance spectroscopies. Bistability in the crystalline phase is also discussed on the basis of the results provided by X‐ray diffraction analysis and temperature‐dependent Mössbauer spectra. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
287.
Aprahamian I Olsen JC Trabolsi A Stoddart JF 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(13):3889-3895
The template-directed synthesis of a bistable tripodal [4]rotaxane, which has cyclobis(paraquat-p-phenylene) (CBPQT4+) as the pi-electron-deficient rings, and tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene units as the pairs of pi-electron-rich recognition sites located on all three legs of the tripodal dumbbell, is described. The chemical and electrochemical oxidation of the [4]rotaxane and its tripodal dumbbell have allowed us to unravel an unprecedented TTF.+ radical cation dimerization. In fact, two types of TTF dimers, namely, the radical cation dimer [TTF.+]2 and the mixed-valence one [(TTF)2].+, have been observed at room temperature for the tripodal dumbbell, whereas, in the case of the [4]rotaxane, only the radical cation dimer [TTF.+]2 is formed. This anomaly can be explained if it is accepted that most of the neutral TTF units in the [4]rotaxane are encircled by CBPQT4+ rings, which renders the formation of the mixed-valence dimer [(TTF)2].+ highly unfavorable. 相似文献
288.
Noticeable positive Doppler effect on optical bistability in an N-type active Raman gain atomic system
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We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity.It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region,which has been known as the positive Doppler effect on optical bistability.In addition,we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type. 相似文献
289.
Controllable optical bistability of Bose-Einstein condensate in an optical cavity with a Kerr medium
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We study the optical bistability for a Bose-Einstein condensate of atoms in a driven optical cavity with a Kerr medium. We find that both the threshold point of optical bistability transition and the width of optical bistability hysteresis can be controlled by appropriately adjusting the Kerr interaction between the photons. In particular, we show that the optical bistability will disappear when the Kerr interaction exceeds a critical value. 相似文献
290.