2,468 research outputs found

    Calculation of d- and q-axis inductances of PM brushless ac machines accounting for Skew

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    A hybrid two-dimensional (2-D) finite-element/analytical technique is described for predicting the d-axis and q-axis inductances of permanent magnet (PM) brushless ac machines, with due account for the influence of skew. Predicted inductances are compared with measured values for two machines having identical stators, which are skewed by one slot-pitch, but which have different rotor topologies, one having surface-mounted magnets and the other having interior magnets

    Online optimal flux-weakening control of permanent-magnet brushless AC drives

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    An enhanced online optimal control strategy, which maximizes the flux-weakening performance of a brushless AC motor, is described, and applied to motors having different rotor topologies: interior (radial or circumferential), inset, and surface-mounted magnet. It enables the maximum inherent power capability of a brushless AC motor to be achieved independent of any variation in its parameters, and facilitates maximum efficiency over the entire speed range. It also results in good transient dynamic performance, since it is coupled with feedforward vector control based on optimal current profiles

    Quasinormal modes and hidden conformal symmetry in the Reissner-Nordstrom black hole

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    It is shown that the scalar wave equation in the near-horizon limit respects a hidden SL(2,R) invariance in the Reissner-Nordstrom (RN) black hole spacetimes. We use the SL(2,R) symmetry to determine algebraically the purely imaginary quasinormal frequencies of the RN black hole. We confirm that these are exactly quasinormal modes of scalar perturbation around the near-extremal black hole.Comment: 17 pages, 1 figure, version to appear in EPJ

    Environmentally Conscious Manufacturing Through Total Cost Management

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    Total Cost Management (TCM) is a business paradigm for managing all company resources and the activities that consume those resources with a focus on stimulating and managing improvements. We address the theoretical approach of TCM to environmental sustainability and present a practical case of using costing approaches to evaluate the sustainability of the manufacture of a recycled product.  Decision aids, the QFD matrix, B2B e-commerce, allowable costs, and market-based pricing are employed to demonstrate that companies can apply the TCM model to integrate environmental policy as an essential component of corporate strategy to achieve and maintain competitive superiority

    The absence of the Kerr black hole in the Ho\v{r}ava-Lifshitz gravity

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    We show that the Kerr metric does not exist as a fully rotating black hole solution to the modified Ho\v{r}ava-Lifshitz (HL) gravity with ΛW=0\Lambda_W=0 and λ=1\lambda=1 case. We perform it by showing that the Kerr metric does not satisfy full equations derived from the modified HL gravity.Comment: 35 pages, no figure

    Diffuse interstitial and multiple cavitary lung lesions due to Talaromyces marneffei infection in a non-HIV patient

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    AbstractA 57-year-old man presented with unproductive cough and dyspnea for 6 months in Fujian Province, China. His misuse of a large amount of steroids (accumulated dose equivalent to 3530 mg prednisolone) resulted in Talaromyces marneffei infection. Chest computed tomographic scan revealed diffuse interstitial and multiple cavitary lung lesions. Treatment with amphotericin B combined with itraconazole resulted in total recovery, with marked regression of lung lesions

    Signature inversion -- manifestation of drift of the rotational axis in triaxial nuclei

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    A possible scheme of realizing shell model calculations for heavy nuclei is based on a deformed basis and the projection technique. Here we present a new development for odd-odd nuclei, in which one starts with triaxially-deformed multi-quasi-particle configurations, builds the shell-model space through exact three-dimensional angular-momentum-projection, and diagonalizes a two-body Hamiltonian in this space. The model enables us to study the old problem of signature inversion from a different view. With an excellent reproduction of the experimental data in the mass-130 region, the results tend to interpret the phenomenon as a manifestation of dynamical drift of the rotational axis with presence of axial asymmetry in these nuclei.Comment: 10 pages, 5 figure

    Two charged strangeonium-like structures observable in the Y(2175)→ϕ(1020)π+π−Y(2175) \to \phi(1020)\pi^{+} \pi^{-} process

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    Via the Initial Single Pion Emission (ISPE) mechanism, we study the ϕ(1020)π+\phi(1020)\pi^{+} invariant mass spectrum distribution of Y(2175)→ϕ(1020)π+π−Y(2175) \to \phi(1020)\pi^{+} \pi^{-}. Our calculation indicates there exist a sharp peak structure (Zs1+Z_{s1}^+) close to the KKˉ∗K\bar{K}^\ast threshold and a broad structure (Zs2+Z_{s2}^+) near the K∗Kˉ∗K^\ast\bar{K}^\ast threshold. In addition, we also investigate the ϕ(1680)→ϕ(1020)π+π−\phi(1680) \to \phi(1020)\pi^{+} \pi^{-} process due to the ISPE mechanism, where a sharp peak around the KKˉ∗K\bar{K}^\ast threshold appears in the ϕ(1020)π+\phi(1020)\pi^{+} invariant mass spectrum distribution. We suggest to carry out the search for these charged strangeonium-like structures in future experiment, especially Belle II, Super-B and BESIII.Comment: 7 pages, 5 figures. Accepted by Eur. Phys. J.
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