4,409 research outputs found

    S-dual Amplitude and D3-Brane Couplings

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    Recently, it has been observed that the IIB scattering amplitudes are compatible with the standard rules of S-duality. Inspired by this observation, we will find the tree-level S-matrix elements of one Ramond-Ramond and three open strings by imposing this symmetry on the tree-level S-matrix elements of one Kalb-Ramond and three open strings. We also find a SL(2, R) invariant form of the D3-brane effective action containing four gauge fields with derivative corrections that was derived from one-loop level four-point amplitude. Using the expansion of the nonlinear SL(2, R) invariant structures, we find the action with derivative corrections at the level of more gauge fieldsComment: 18 page

    On circular Bragg regimes in ellipsometry spectra of ambichiral sculptured thin films

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    The generalized ellipsometry formalism is used for a right handed ambichiral sculptured thin film.The amplitude ratios and phase differences of this structure are extracted from the amplitude transmission ratios. The results showed that the circular Bragg regimes appear with abruptly changes in ellipsometry spectrum as wavelength, where the selective circular transmission is maximized.Comment: 3 figures. arXiv admin note: substantial text overlap with arXiv:1206.042

    Optical properties of gyrotropic polygonal chiral thin films

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    The optical response of gyrotropic and non-gyrotropic dielectric polygonal chiral thin films were investigated using transfer matrix method. The influence of gyrotropy factor, porosity and incident angle of light on Bragg regimes, selective reflection and transmission were reported. The results revealed that the Fabry-Perot oscillations were affected by gyrotropy factor and porosity of polygonal chiral thin films.Comment: 10 figure

    On optical rotation and selective transmission in ambichiral sculptured thin films

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    The optical rotation and selective transmission spectrum of ambichiral sculptured thin films using transfer matrix method have been calculated. The results of optical modeling showed that optical characteristics ambichiral sculptured thin films are the same as chiral sculptured thin films in lower angular rotations. In higher angular rotations appear two circular Bragg regimes. The primary at shorter wavelengths reflects LCP light and the secondary at longer wavelengths reflects RCP light. The optical properties of ambichiral sculptured thin films with twist and layer defects as spectral holes in circular Bragg regimes have been reported.Comment: 9 pages,3 figure

    Using physiological measures in conjunction with other UX approaches for better understanding of the player's gameplay experiences

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    The goal of video games is to challenge and entertain the players. Successful video games deliver experience that impact players on a level of arousal. Therefore undertaking a user experience (UX) study is crucial to ensure that a game achieves both critical and financial success. However, traditional usability methods (observation, subjective reporting, questionnaire, and interview) have a number of limitations on game user research. In this study we capture player's physiological measures during a gameplay session, to indicate micro-events that have caused changes in their body signals. At the post-gameplay interviews we ask participants to comment and describe their feelings on the selected events. The aim of this study is not to over-interpret physiological measures, but on using blips in measures to help identify key points in a game, which we then use to investigate further with the participant. This approach provides a method that can identify not only the negative user experience and usability issues but also the events which have a positive impact on player's experience.Comment: 15 Pages. This paper has been presented at Games Research Methods Seminar,8-9 April 2010,University of Tampere, Finlan

    T-dual RR couplings on D-branes from S-matrix elements

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    Using the linear T-dual ward identity associated with the NSNS gauge transformations, some RR couplings on Dp_p-branes have been found at order O(Ξ±β€²2)O(\alpha'^2). We examine the C(pβˆ’1)C^{(p-1)} couplings with the S-matrix elements of one RR, one graviton and one antisymmetric B-field vertex operators. We find the consistency of T-dual S-matrix elements and explicit results of scattering string amplitude and show that the string amplitude reproduces these couplings as well as some other couplings. This illustration is found for C(pβˆ’3)C^{(p-3)} couplings in the literature which is extended to the C(pβˆ’1)C^{(p-1)} couplings in this paper.Comment: 23 pages. V2: it appears in PR

    Optimal Trajectory-Planning of UAVs via B-Splines and Disjunctive Programming

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    This paper investigates an efficient algorithm for trajectory planning problem of autonomous unmanned aerial vehicles which fly over three-dimensional terrains. The proposed algorithm combines convex optimization with disjunctive programming and receding horizon concept, which has many advantages, such as a high computational speed. Disjunctive programming is applied in order to relax the non-convex constraints of the problem. Moreover, the B-spline curves are employed to represent the trajectories which should be generated in the optimization process

    Special Biserial Cluster-tilted Algebras

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    We give a complete description of all special biserial cluster-tilted algebras over a finite dimensional hereditary algebra H over an algebraically closed field K

    Characteristics of plasmonic at a metal /chiral sculptured thin film interface

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    The propagation of surface plasmon polariton at an interface of metallic thin film and chiral sculptured thin film theoretically has been investigated using the transfer matrix method in the Kretschman configuration. The optical absorption of structure as a function of polar incident angle for linear polarization P and S has been calculated at different structural parameters. The results show that exist multiple plasmon peaks for P-polarization, while there are the weak plasmon peaks when incident of light is S- polarized plane wave

    Surface plasmon resonance of two segmented Au Cu nanowires in polycarbonate template

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    Two segmented gold copper nanowires were grown inside the pores of polycarbonate track (PCT) etched membranes from two separate solutions by electrodeposition method. Optical absorption spectra of two segmented Au Cu nanowires in PCT template were shown a surface plasmon- polariton peak appeared at about 900 nm for incident angle of theta = 65 degrees but for theta= 0 there are not any peaks in spectra
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