485 research outputs found

    Superposition in nonlinear wave and evolution equations

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    Real and bounded elliptic solutions suitable for applying the Khare-Sukhatme superposition procedure are presented and used to generate superposition solutions of the generalized modified Kadomtsev-Petviashvili equation (gmKPE) and the nonlinear cubic-quintic Schroedinger equation (NLCQSE).Comment: submitted to International Journal of Theoretical Physics, 23 pages, 2 figures, style change

    Study of the 12C+12C fusion reactions near the Gamow energy

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    The fusion reactions 12C(12C,a)20Ne and 12C(12C,p)23Na have been studied from E = 2.10 to 4.75 MeV by gamma-ray spectroscopy using a C target with ultra-low hydrogen contamination. The deduced astrophysical S(E)* factor exhibits new resonances at E <= 3.0 MeV, in particular a strong resonance at E = 2.14 MeV, which lies at the high-energy tail of the Gamow peak. The resonance increases the present non-resonant reaction rate of the alpha channel by a factor of 5 near T = 8x10^8 K. Due to the resonance structure, extrapolation to the Gamow energy E_G = 1.5 MeV is quite uncertain. An experimental approach based on an underground accelerator placed in a salt mine in combination with a high efficiency detection setup could provide data over the full E_G energy range.Comment: 4 Pages, 4 figures, accepted for publication in Phys. Rev. Let

    Algebraic totality, towards completeness

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    Finiteness spaces constitute a categorical model of Linear Logic (LL) whose objects can be seen as linearly topologised spaces, (a class of topological vector spaces introduced by Lefschetz in 1942) and morphisms as continuous linear maps. First, we recall definitions of finiteness spaces and describe their basic properties deduced from the general theory of linearly topologised spaces. Then we give an interpretation of LL based on linear algebra. Second, thanks to separation properties, we can introduce an algebraic notion of totality candidate in the framework of linearly topologised spaces: a totality candidate is a closed affine subspace which does not contain 0. We show that finiteness spaces with totality candidates constitute a model of classical LL. Finally, we give a barycentric simply typed lambda-calculus, with booleans B{\mathcal{B}} and a conditional operator, which can be interpreted in this model. We prove completeness at type BnB{\mathcal{B}}^n\to{\mathcal{B}} for every n by an algebraic method

    K^+ production in baryon-baryon and heavy-ion collisions

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    Kaon production cross sections in nucleon-nucleon, nucleon-delta and delta-delta interactions are studied in a boson exchange model. For the latter two interactions, the exchanged pion can be on-mass shell, only contributions due to a virtual pion are included via the Peierls method by taking into account the finite delta width. With these cross sections and also those for pion-baryon interactions, subthreshold kaon production from heavy ion collisions is studied in the relativistic transport model.Comment: to appear in Phys. Rev.

    Mixing Bandt-Pompe and Lempel-Ziv approaches: another way to analyze the complexity of continuous-states sequences

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    In this paper, we propose to mix the approach underlying Bandt-Pompe permutation entropy with Lempel-Ziv complexity, to design what we call Lempel-Ziv permutation complexity. The principle consists of two steps: (i) transformation of a continuous-state series that is intrinsically multivariate or arises from embedding into a sequence of permutation vectors, where the components are the positions of the components of the initial vector when re-arranged; (ii) performing the Lempel-Ziv complexity for this series of `symbols', as part of a discrete finite-size alphabet. On the one hand, the permutation entropy of Bandt-Pompe aims at the study of the entropy of such a sequence; i.e., the entropy of patterns in a sequence (e.g., local increases or decreases). On the other hand, the Lempel-Ziv complexity of a discrete-state sequence aims at the study of the temporal organization of the symbols (i.e., the rate of compressibility of the sequence). Thus, the Lempel-Ziv permutation complexity aims to take advantage of both of these methods. The potential from such a combined approach - of a permutation procedure and a complexity analysis - is evaluated through the illustration of some simulated data and some real data. In both cases, we compare the individual approaches and the combined approach.Comment: 30 pages, 4 figure

    Модернизация технологического процесса на газораспределительной станции Барабинского линейного производственного управления

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    Выпускная квалификационная работа содержит 160 страницы машинописного текста, 29 таблиц, 27 рисунков, 1 список использованных источников из 18 наименований, 9 приложений. Объектом исследования является газораспределительная станция. Цель работы – разработка автоматизированной системы управления ГРС с использованием ПЛК, на основе выбранной SCADA-системы. В данном отчете описан производственный процесс на газораспределительной станции Барабинского ЛПУМГ, а также выявлены производственные проблемы и даны рекомендации для совершенствования системы контроля и управления этого процесса.Final qualifying work contains 160 pages of typewritten text, 29 tables, 27 figures, 1 list of references from 18 names, 9 applications. The object of research is a gas distribution station. The purpose of work - development of automated gas distribution station control system using PLC, based on the selected SCADA-system. This report describes a manufacturing process at a gas distribution station Baraba LPUMG and identified production problems and recommendations for improving the monitoring and management of this process

    Exploring language as the “in-between”

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    Assuming a performative notion of language, this contribution addresses how language functions as a symbolic means and asks for its function for the dialogical self. In accordance with a non-individualistic notion, individuals are related to each other within and by virtue of an in-between. This in-between is called “spacetime of language”: a dynamic evolving across time, perceived as linguistic forms with their chronotopology and the positionings of the performers (self as-whom to other as-whom). With respect to the linguistic forms, the specificity of language functioning is described by Bühler’s term of displacement. The effect of displacement is to generate sharedness by inducing a movement the partners follow, going beyond their actual, sensitive contact. Symbolic displacement, expanding Bühler’s notion, is particularly interesting with regard to the dialogical self: it permits the social construction of several perspectives on self, other, and reality—positions and voices informing the self’s performances

    Effects of Compression and Collective Expansion on Particle Emission from Central Heavy-Ion Reactions

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    Conditions under which compression occurs and collective expansion develops in energetic reactions of heavy nuclei, are analyzed, together with their effects on emitted light baryons and pions. Within transport simulations, it is shown that shock fronts perpendicular to beam axis form in head-on reactions. The fronts separate hot compressed matter from normal. As impact parameter increases, the angle of inclination of the fronts relative to beam axis decreases, and in-between the fronts a weak tangential discontinuity develops. Hot matter exposed to the vacuum in directions perpendicular to shock motion (and parallel to fronts), starts to expand sideways, early within reactions. Expansion in the direction of shock motion follows after the shocks propagate through nuclei, but due to the delay does not acquire same strength. Expansion affects angular distributions, mean-energy components, shapes of spectra and mean energies of different particles emitted into any one direction, and further particle yields. Both the expansion and a collective motion associated with the weak discontinuity, affect the magnitude of sideward flow within reaction plane. Differences in mean particle energy components in and out of the reaction plane in semicentral collisions, depend sensitively on the relative magnitude of shock speed in normal matter and speed of sound in hot matter.Comment: 71 pages, 33 figures (available on request), report MSUCL-94

    Exclusive Photoproduction of Large Momentum-Transfer K and K* Mesons

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    The reactions gamma p -> K+ Lambda and gamma p -> K* Lambda are analyzed within perturbative QCD, allowing for diquarks as quasi-elementary constituents of baryons. The diquark-model parameters and the quark-diquark distribution amplitudes of proton and Lambda are taken from previous investigations of electromagnetic baryon form factors and Compton-scattering off protons. Unpolarized differential cross sections and polarization observables are computed for different choices of the K and K* distribution amplitudes. The asymptotic form of the K distribution amplitude (proportional to x1 x2) is found to provide a satisfactory description of the K photoproduction data.Comment: 32 pages, 7 figures available as tared, compressed and uuencoded PS-file
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