82,212 research outputs found

    Complex Monge-Amp\`ere equations on quasi-projective varieties

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    We introduce generalized Monge-Amp\`ere capacities and use these to study complex Monge-Amp\`ere equations whose right-hand side is smooth outside a divisor. We prove, in many cases, that there exists a unique normalized solution which is smooth outside the divisor

    The viscoplasticity theory based on overstress applied to the modeling of a nickel base superalloy at 815 C

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    Short term strain rate change, creep and relaxation tests were performed in an MTS computer controlled servohydraulic testing machine. Aging and recovery were found to be insignificant for test times not exceeding 30 hrs. The material functions and constants of the theory were identified from results of strain rate change tests. Numerical integration of the theory for relaxation and creep tests showed good predictive capabilities of the viscoplasticity theory based on overstress

    De Sitter Bounces

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    By analytically continuing recently-found instantons, we construct time-dependent solutions of Einstein-Maxwell de Sitter gravity which smoothly bounce between two de Sitter phases. These deformations of de Sitter space undergo several stages in their time evolution. Four and five-dimensional de Sitter bounces can be lifted to non-singular time-dependent solutions of M-theory.Comment: Latex, 18 pages, 5 figure

    The Static Dielectric Constant of a Colloidal Suspension

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    We derive an expression for the static dielectric constant of the colloidal susp ensions based on the electrokinetic equations. The analysis assumes that the ions have the same diffusivity, and that the double layer is much thinner than the radius of curvature of the particles. It is shown that the dielectric increment of the double layer polarization mechanism is originated from the free energy stored in the salt concentration inhomogeniety. We also show that the dominant polarization charges in the theory are at the electrodes, rather than close to the particles.Comment: 15 pages, 1 figur

    Spectrum-generating Symmetries for BPS Solitons

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    We show that there exist nonlinearly realised duality symmetries that are independent of the standard supergravity global symmetries, and which provide active spectrum-generating symmetries for the fundamental BPS solitons. The additional ingredient, in any spacetime dimension, is a single scaling transformation that allows one to map between BPS solitons with different masses. Without the inclusion of this additional transformation, which is a symmetry of the classical equations of motion, but not the action, it is not possible to find a spectrum-generating symmetry. The necessity of including this scaling transformation highlights the vulnerability of duality multiplets to quantum anomalies. We argue that fundamental BPS solitons may be immune to this threat.Comment: References added. Latex, 29 page

    Dilatonic p-brane solitons

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    We find new 4-brane and 5-brane solitons in massive gauged D=6D=6, N=2N=2 and D=7D=7, N=1N=1 supergravities. In each case, the solutions preserve half of the original supersymmetry. These solutions make use of the metric and dilaton fields only. We also present more general dilatonic (D2)(D-2)-branes in DD dimensions.Comment: 9 pages, Latex, no figure
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