45,154 research outputs found

    Finite-Dimensional Representations of the Quantum Superalgebra Uq_{q}[gl(2/2)]: I. Typical representations at generic qq

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    In the present paper we construct all typical finite-dimensional representations of the quantum Lie superalgebra Uq[gl(2/2)]U_{q}[gl(2/2)] at generic deformation parameter qq. As in the non-deformed case the finite-dimensional Uq[gl(2/2)]U_{q}[gl(2/2)]-module WqW^{q} obtained is irreducible and can be decomposed into finite-dimensional irreducible Uq[gl(2)gl(2)]U_{q}[gl(2)\oplus gl(2)]-submodules VkqV^{q}_{k}Comment: published version. Some formulae are rewritten in more compact for

    Anomalous Aharonov-Bohm conductance oscillations from topological insulator surface states

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    We study transport properties of a topological insulator nanowire when a magnetic field is applied along its length. We predict that with strong surface disorder, a characteristic signature of the band topology is revealed in Aharonov Bohm (AB) oscillations of the conductance. These oscillations have a component with anomalous period Φ0=hc/e\Phi_0=hc/e, and with conductance maxima at odd multiples of 12Φ0\frac12\Phi_0, i.e. when the AB phase for surface electrons is π\pi. This is intimately connected to the band topology and a surface curvature induced Berry phase, special to topological insulator surfaces. We discuss similarities and differences from recent experiments on Bi2_2Se3_3 nanoribbons, and optimal conditions for observing this effect.Comment: 7 pages, 2 figure

    A new root-knot nematode, Meloidogyne moensi n. sp. (Nematoda : Meloidogynidae), parasitizing Robusta coffee from Western Highlands, Vietnam

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    A new root-knot nematode, parasitizing Robusta coffee in Dak Lak Province, Western Highlands of Vietnam, is described as Meloidogyne moensi n. sp. Morphological and molecular analyses demonstrated that this species differs clearly from other previously described root-knot nematodes. Morphologically, the new species is characterized by a swollen body of females with a small posterior protuberance that elongated from ovoid to saccate; perineal patterns with smooth striae, continuous and low dorsal arch; lateral lines marked as a faint space or linear depression at junction of the dorsal and ventral striate; distinct phasmids; perivulval region free of striae; visible and wide tail terminus surrounding by concentric circles of striae; medial lips of females in dumbbell-shaped and slightly raised above lateral lips; female stylet is normally straight with posteriorly sloping stylet knobs; lip region of second stage juvenile (J2) is not annulated; medial lips and labial disc of J2 formed dumbbell shape; lateral lips are large and triangular; tail of J2 is conoid with rounded unstriated tail tip; distinct phasmids and hyaline; dilated rectum. Meloidogyne moensi n. sp. is most similar to M. africana, M. ottersoni by prominent posterior protuberance. Results of molecular analysis of rDNA sequences including the D2-D3 expansion regions of 28S rDNA, COI, and partial COII/16S rRNA of mitochondrial DNA support for the new species status

    Simulation of decelerating landing approaches on an externally blown flap STOL transport airplane

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    A fixed-base simulator program was conducted to define the problems and methods for solution associated with performing decelerating landing approaches on a representative STOL transport having a high wing and equipped with an external-flow jet flap in combination with four high-bypass-ratio fan-jet engines. Real-time digital simulation techniques were used. The computer was programed with equations of motion for six degrees of freedom and the aerodynamic inputs were based on measured wind-tunnel data. The pilot's task was to capture the localizer and the glide slope and to maintain them as closely as possible while decelerating from an initial airspeed of 140 knots to a final airspeed of 75 knots, while under IFR conditions

    Finite-Dimensional Representations of the Quantum Superalgebra Uq_{q}[gl(2/2)]: II. Nontypical representations at generic qq

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    The construction approach proposed in the previous paper Ref. 1 allows us there and in the present paper to construct at generic deformation parameter qq all finite--dimensional representations of the quantum Lie superalgebra Uq[gl(2/2)]U_{q}[gl(2/2)]. The finite--dimensional Uq[gl(2/2)]U_{q}[gl(2/2)]-modules WqW^{q} constructed in Ref. 1 are either irreducible or indecomposible. If a module WqW^{q} is indecomposible, i.e. when the condition (4.41) in Ref. 1 does not hold, there exists an invariant maximal submodule of WqW^{q}, to say IkqI_{k}^{q}, such that the factor-representation in the factor-module Wq/IkqW^{q}/I_{k}^{q} is irreducible and called nontypical. Here, in this paper, indecomposible representations and nontypical finite--dimensional representations of the quantum Lie superalgebra Uq[gl(2/2)]U_{q}[gl(2/2)] are considered and classified as their module structures are analized and the matrix elements of all nontypical representations are written down explicitly.Comment: Latex file, 49 page

    Wind-tunnel free-flight investigation of a model of a forward-swept-wing fighter configuration

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    A wind-tunnel free-flight investigation was conducted to study the dynamic stability characteristics of a model of a forward-swept-wing fighter-airplane configuration at high angles of attack. Various other wind-tunnel techniques employed in the study included static- and dynamic- (forced-oscillation) force tests, free-to-roll tests, and flow-visualization tests. A unique facet of the study was the extreme level of static pitch instability (in excess of negative 32-percent static margin) inherent in the airframe design which precluded free-flight testing without stability augmentation in pitch. Results are presented which emphasize the high-angle-of-attack aerodynamics and the vehicle-component contributions to these characteristics. The effects of these aerodynamic characteristics on the high-angle-of-attack flying qualities of the configuration are discussed in terms of results of the wind-tunnel free-flight tests
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