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51.
We study information processing in populations of boolean networks with evolving connectivity and systematically explore the interplay between the learning capability, robustness, the network topology, and the task complexity. We solve a long-standing open question and find computationally that, for large system sizes N, adaptive information processing drives the networks to a critical connectivity K(c)=2. For finite size networks, the connectivity approaches the critical value with a power law of the system size N. We show that network learning and generalization are optimized near criticality, given that the task complexity and the amount of information provided surpass threshold values. Both random and evolved networks exhibit maximal topological diversity near K(c). We hypothesize that this diversity supports efficient exploration and robustness of solutions. Also reflected in our observation is that the variance of the fitness values is maximal in critical network populations. Finally, we discuss implications of our results for determining the optimal topology of adaptive dynamical networks that solve computational tasks. 相似文献
52.
We report a narrow-linewidth, tunable, gain-switched Cr:ZnSe laser operating between 2255 and 2455 nm. The spectral width of the laser was reduced from 125 nm to 0.3 nm by using injection seeding. Seeding was achieved with a second tunable CW Cr:ZnSe laser. The output wavelength was varied by tuning the wavelength of the seed laser. The seeded oscillator produced as high as 157 μJ pulses with 598 μJ incident pump pulse energy at a repetition rate of 1 kHz. The slope efficiency was determined to be 26%. 相似文献
53.
Silvia Todros Arturo N. Natali Giuseppe Pace Vito Di Noto 《Journal of Polymer Science.Polymer Physics》2014,52(5):409-418
The effect of steam on chemical structure and mechanical properties of renewable poly(ether‐block‐amide)s (PEBAs) is investigated by different characterization techniques, i.e. FT‐IR, TGA, DSC, DMA, and BES. Steam sterilization is a mandatory process for materials used in medical applications. This process, employed during clinical practice and replicated in this study, affects polymer structure and morphology. Steam induces an increase of polyamide (PA) crystallinity in PEBAs with a majority of PA domains, due to the conformational transition from α‐helix to parallel and anti‐parallel β‐sheet, with stronger hydrogen bonding. In PEBAs with longer polyether (PE) blocks, steam induces an increase of random PA domains and the formation of a more extended hydrogen bonding network between ether and amide moieties of the two segments. As a consequence of these microdomain conformational variations, relevant changes occur in molecular relaxations as demonstrated by DMA and BES results. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 409–418 相似文献
54.
N. Antoine-Vincent F. Natali D. Byrne P. Disseix A. Vasson J. Leymarie F. Semond J. Massies 《Superlattices and Microstructures》2004,36(4-6):599
In a recent publication [N. Antoine-Vincent, F. Natali, D. Byrne, A. Vasson, P. Disseix, J. Leymarie, M. Leroux, F. Semond, J. Massies, Phys. Rev. B 68 (2003) 153313], we have highlighted for the first time the exciton–photon strong coupling in a GaN-based microcavity and obtained a Rabi splitting of 31 meV persistent at 77 K. Our aim is now to study the feasibility of GaN-based microcavities for which the strong coupling regime would be maintained at room temperature. A complex heterostructure containing GaN/AlGaN quantum wells (QWs) is investigated by photoreflectivity and reflectivity at 5 K. The QW thickness is 3 nm and the Al composition and thickness of the barriers are respectively 0.11 and 10 nm. From the modeling of the experimental spectra, the values of the oscillator strength, the energy and the broadening parameter of the QW fundamental transition are determined; the broadening is found to be relatively weak (15 meV). Simulations of microcavities containing QWs have then been performed including this set of parameters: a theoretical Rabi splitting of 34 meV is obtained at 5 K. Considering an additional broadening induced by the increase of the temperature (23 meV), the strong coupling regime could be maintained theoretically at room temperature in such a structure. This is due to the low value of the inhomogeneous broadening related to the QW transition which is lower than in bulk GaN. The influence of the QW number and the nature of the Bragg mirror on the Rabi splitting is then discussed in realistic structures. 相似文献
55.
H. Cobbaert P. R. Hobson R. Arnold J. L. Bailly J. F. Balland M. Barth J. H. Bartley M. Boratav F. W. Bullock M. Callichio M. Coupland H. Drevermann B. G. Duff O. Erriquez M. J. Esten D. Geiregat K. Geissler F. Grard V. P. Henri A. Herve F. F. Heymann J. Hrubec D. C. Imrie E. Johannsson J. Kesteman P. Lecoq G. J. Lush G. Maurer M. t. Muciaccia S. Natali S. Nuzzo G. Neuhofer P. Olivier R. Roosen F. Ruggieri A. Taurok S. P. K. Tavernier M. C. Touboul A. M. Touchard O. R. Williams 《Zeitschrift fur Physik C Particles and Fields》1987,36(4):577-591
In the first holographic bubble chamber experiment — the HOBC experiment — we have accumulated a total of 40000 holograms with particle interactions. We have determined the total charm pair cross section inpN collisions to be 23.3 ?7.7 +10 μb and 3.6 ?1.7 +2.3 μb for 360 and 200 GeV/c incident protons respectively. We have assumed a linear dependence of the cross section on the atomic number of the target. This experiment has demonstrated the feasibility of holographic recording in small bubble chambers. Assuming that the charm cross section can be described by the standard QCD factorized expression with gluon fusion and quark-antiquark annihilation, we have used our measured charm cross sections with other measurements to determine the effective charmed quark mass to be 1.8 ?0.35 +0.25 GeV/c2. TheK factor, which describes the importance of the higher order corrections, is calculated to be 9.8 ?6.9 +12.5 (See noted added in proof.) 相似文献
56.
Fbio M. Amorin Natali Ademir Pastor Ferreira 《Journal of Mathematical Analysis and Applications》2008,347(2):428-441
In the present paper we show some results concerning the orbital stability of dnoidal standing wave solutions and orbital instability of cnoidal standing wave solutions to the following Klein–Gordon equation:
utt−uxx+u−|u|2u=0.