35,933 research outputs found

    How to select combination operators for fuzzy expert systems using CRI

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    A method to select combination operators for fuzzy expert systems using the Compositional Rule of Inference (CRI) is proposed. First, fuzzy inference processes based on CRI are classified into three categories in terms of their inference results: the Expansion Type Inference, the Reduction Type Inference, and Other Type Inferences. Further, implication operators under Sup-T composition are classified as the Expansion Type Operator, the Reduction Type Operator, and the Other Type Operators. Finally, the combination of rules or their consequences is investigated for inference processes based on CRI

    QCD description of backward vector meson hard electroproduction

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    We consider backward vector meson exclusive electroproduction off nucleons in the framework of collinear QCD factorization. Nucleon to vector meson transition distribution amplitudes arise as building blocks for the corresponding factorized amplitudes. In the near-backward kinematics, the suggested factorization mechanism results in the dominance of the transverse cross section of vector meson production (σTσL\sigma_T \gg \sigma_L) and in the characteristic 1/Q81/Q^8-scaling behavior of the cross section. We evaluate nucleon to vector meson TDAs in the cross-channel nucleon exchange model and present estimates of the differential cross section for backward ρ0\rho^0, ω\omega and ϕ\phi meson production off protons. The resulting cross sections are shown to be measurable in the forthcoming JLab@12 GeV experiments.Comment: 37 pages, 8 figures, 1 tabl

    Nucleon-to-pion transition distribution amplitudes and backward electroproduction of pions

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    Baryon to meson transition distribution amplitudes (TDAs), non-diagonal matrix elements of the nonlocal three quark operator between a nucleon and a meson state, extend the concept of generalized parton distributions. These non-perturbative objects which encode the information on three quark correlations inside the nucleon may be accessed experimentally in backward meson electroproduction reactions. We suggest a general framework for modelling nucleon to pion (pi N) TDAs employing the spectral representation for pi N TDAs in terms of quadruple distributions. The factorized Ansatz for quadruple distributions with input from the soft-pion theorem for pi N TDAs is proposed. It is to be complemented with a D-term like contribution from the nucleon exchange in the cross channel. We present our estimates of the unpolarized cross section and of the transverse target single spin asymmetry for backward pion electroproduction within the QCD collinear factorization approach in which the non-perturbative part of the amplitude involves pi N TDAs. The cross section is sizable enough to be studied in high luminosity experiments such as J-lab@12GeV and EIC.Comment: proceedings of QNP 2012, Sixth International Conference on Quarks and Nuclear Physics, April 16-20, 2012, Ecole Polytechnique, Palaiseau, Franc

    One Hour of Chemical Demonstrations

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    This article describes a diverse set of chemistry demonstrations especially selected to encourage student interaction and to be easily transported. The demonstrations may be presented at a level that can be tailored to any audience– from very young children to high school students planning careers in science. An ideal environment is a small classroom with 20-30 students where everyone can take part in the discussion. Once the chemicals are prepared, the collection of demonstrations takes about ten minutes to set-up, and one hour (or less) to perform. Very little is needed at the visiting site, no more than a table and a pitcher of water. A single electrical outlet is useful, but not essential. In Table 2 th

    The power of VNA-driven quasi-optics to sense group molecular action in condensed phase systems

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    © © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC, UK) for generous support (EP/1014845)

    Quantum phase transitions in the quasi-periodic kicked rotor

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    We present a microscopic theory of transport in quasi-periodically driven environments (`kicked rotors'), as realized in recent atom optic experiments. We find that the behavior of these systems depends sensitively on the value of Planck's constant h~\tilde h: for irrational values of h~/(4π)\tilde h/(4\pi) they fall into the universality class of disordered electronic systems and we derive the microscopic theory of the ensuing localization phenomena. In contrast, for rational values the rotor-Anderson insulator acquires an infinite (static) conductivity and turns into a `super-metal'. Signatures of the corresponding metal/super-metal transition are discussed.Comment: 4 pages, 1 figure, 1 tabl
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