7,165 research outputs found

    On the Fourier transform of the characteristic functions of domains with C1C^1 -smooth boundary

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    We consider domains D⊆RnD\subseteq\mathbb R^n with C1C^1 -smooth boundary and study the following question: when the Fourier transform 1D^\hat{1_D} of the characteristic function 1D1_D belongs to Lp(Rn)L^p(\mathbb R^n)?Comment: added two references; added footnotes on pages 6 and 1

    Three-point correlation function of a scalar mixed by an almost smooth random velocity field

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    We demonstrate that if the exponent γ\gamma that measures non-smoothness of the velocity field is small then the isotropic zero modes of the scalar's triple correlation function have the scaling exponents proportional to γ\sqrt{\gamma}. Therefore, zero modes are subleading with respect to the forced solution that has normal scaling with the exponent γ\gamma.Comment: 13 pages, RevTeX 3.

    Solving the two-center nuclear shell-model problem with arbitrarily-orientated deformed potentials

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    A general new technique to solve the two-center problem with arbitrarily-orientated deformed realistic potentials is demonstrated, which is based on the powerful potential separable expansion method. As an example, molecular single-particle spectra for 12^{12}C + 12^{12}C →\to 24^{24}Mg are calculated using deformed Woods-Saxon potentials. These clearly show that non-axial symmetric configurations play a crucial role in molecular resonances observed in reaction processes for this system at low energy

    Strong effect of weak diffusion on scalar turbulence at large scales

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    Passive scalar turbulence forced steadily is characterized by the velocity correlation scale, LL, injection scale, ll, and diffusive scale, rdr_d. The scales are well separated if the diffusivity is small, rd≪l,Lr_d\ll l,L, and one normally says that effects of diffusion are confined to smaller scales, r≪rdr\ll r_d. However, if the velocity is single scale one finds that a weak dependence of the scalar correlations on the molecular diffusivity persists to even larger scales, e.g. l≫r≫rdl\gg r\gg r_d \cite{95BCKL}. We consider the case of L≫lL\gg l and report a counter-intuitive result -- the emergence of a new range of large scales, L≫r≫l2/rdL\gg r\gg l^2/r_d, where the diffusivity shows a strong effect on scalar correlations.Comment: 4 pages, 1 figure, submitted to Physics of Fluid
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