32 research outputs found

    Theoretical investigation on the possibility of preparing left-handed materials in metallic magnetic granular composites

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    We investigate the possibility of preparing left-handed materials in metallic magnetic granular composites. Based on the effective medium approximation, we show that by incorporating metallic magnetic nanoparticles into an appropriate insulating matrix and controlling the directions of magnetization of metallic magnetic components and their volume fraction, it may be possible to prepare a composite medium of low eddy current loss which is left-handed for electromagnetic waves propagating in some special direction and polarization in a frequency region near the ferromagnetic resonance frequency. This composite may be easier to make on an industrial scale. In addition, its physical properties may be easily tuned by rotating the magnetization locally.Comment: 5 figure

    Electron energy loss and induced photon emission in photonic crystals

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    The interaction of a fast electron with a photonic crystal is investigated by solving the Maxwell equations exactly for the external field provided by the electron in the presence of the crystal. The energy loss is obtained from the retarding force exerted on the electron by the induced electric field. The features of the energy loss spectra are shown to be related to the photonic band structure of the crystal. Two different regimes are discussed: for small lattice constants aa relative to the wavelength of the associated electron excitations λ\lambda, an effective medium theory can be used to describe the material; however, for a∌λa\sim\lambda the photonic band structure plays an important role. Special attention is paid to the frequency gap regions in the latter case.Comment: 12 pages, 7 figure

    The normalisation of drug supply: The social<i>supply</i>of drugs as the “other side” of the history of normalisation

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    Aims: Describes how the relative normalisation of recreational drug use in the UK has been productive of, and fused with, the relatively normalised and non-commercial social supply of recreational drugs. Methods: Semi-structured interviews with 60 social suppliers of recreational drugs in two studies (involving a student population n = 30 and general population sample n = 30). Respondents were recruited via purposive snowball sampling and local advertising. Findings: Both samples provided strong evidence of the normalised supply of recreational drugs in micro-sites of friendship and close social networks. Many social suppliers described “drift” into social supply and normalised use was suggested to be productive of supply relationships that both suppliers and consumers regard as something less than “real” dealing in order to reinforce their preconceptions of themselves as relatively non-deviant. Some evidence for a broader acceptance of social supply is also presented. Conclusions: The fairly recent context of relative normalisation of recreational drug use has coalesced with the social supply of recreational drugs in micro-sites of use and exchange whereby a range of “social” supply acts (sometimes even involving large amounts of drugs/money) have become accepted as something closer to gift-giving or friendship exchange dynamics within social networks rather than dealing proper. To some degree, there is increasing sensitivity to this within the criminal justice system

    A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership

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    Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Experimental progress in positronium laser physics

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    Compilação atualizada das espécies de morcegos (Chiroptera) para a AmazÎnia Brasileira

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    Thermoplasmonics in Thin Metal Films

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