1,590 research outputs found

    SDL: A Surface Description Language

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    A new interpreted language specifically designed for surface grid generation is introduced. Many unique aspects of the language are discussed, including the farray, vector, curve, and surface data types and the operators used to manipulate them. Custom subroutine libraries written in the language are used to easily build surface grids for generic missile shapes

    Heavy fermion superconductivity in the filled skutterudite compound PrOs4_4Sb12_{12}

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    The filled skutterudite compound \PrOsSb{} has been found to exhibit superconductivity with a critical temperature Tc=1.85T_\mathrm{c} = 1.85 K that develops out of a heavy Fermi liquid with an effective mass m50mem^{*} \approx 50 m_\mathrm{e}. The current experimental situation regarding the heavy fermion state, the superconducting state, and a high field, low temperature phase that is apparently associated with magnetic or quadrupolar order in \PrOsSb{} is briefly reviewed herein.Comment: 4 pages, 2 figures, presented at the LT23 23rd International Conference on Low Temperature Physics, Hiroshima, Japa

    Toward optimal multi-objective models of network security: Survey

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    Information security is an important aspect of a successful business today. However, financial difficulties and budget cuts create a problem of selecting appropriate security measures and keeping networked systems up and running. Economic models proposed in the literature do not address the challenging problem of security countermeasure selection. We have made a classification of security models, which can be used to harden a system in a cost effective manner based on the methodologies used. In addition, we have specified the challenges of the simplified risk assessment approaches used in the economic models and have made recommendations how the challenges can be addressed in order to support decision makers

    Impurity induced density of states and residual transport in nonunitary superconductors

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    We obtain general expressions for the residual density of states, electrical conductivity and thermal conductivity for non-unitary superconductors due to impurity scattering. We apply the results to the so-called `B phase' of PrOs4Sb12, which we describe using a non-unitary gap function derived from symmetry considerations. The conductivity tensor has inequivalent diagonal components due to off-axis nodal positions which may be detectable in experiments.Comment: 8 pages, 1 figur

    Anomalous Paramagnetic Magnetization in Mixed State of CeCoIn5_5 single crystals

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    Magnetization and torque measurements were performed on CeCoIn5_5 single crystals to study the mixed-state thermodynamics. These measurements allow the determination of both paramagnetic and vortex responses in the mixed-state magnetization. The paramagnetic magnetization is suppressed in the mixed state with the spin susceptibility increasing with increasing magnetic field. The dependence of spin susceptibility on magnetic field is due to the fact that heavy electrons contribute both to superconductivity and paramagnetism and a large Zeeman effect exists in this system. No anomaly in the vortex response was found within the investigated temperature and field range

    Superconductivity, magnetic order, and quadrupolar order in the filled skutterudite system Pr1x_{1-x}Ndx_{x}Os4_4Sb12_{12}

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    Superconductivity, magnetic order, and quadrupolar order have been investigated in the filled skutterudite system Pr1x_{1-x}Ndx_{x}Os4_4Sb12_{12} as a function of composition xx in magnetic fields up to 9 tesla and at temperatures between 50 mK and 10 K. Electrical resistivity measurements indicate that the high field ordered phase (HFOP), which has been identified with antiferroquadruoplar order, persists to xx \sim 0.5. The superconducting critical temperature TcT_c of PrOs4_4Sb12_{12} is depressed linearly with Nd concentration to xx \sim 0.55, whereas the Curie temperature TFMT_{FM} of NdOs4_4Sb12_{12} is depressed linearly with Pr composition to (1x1-x) \sim 0.45. In the superconducting region, the upper critical field Hc2(x,0)H_{c2}(x,0) is depressed quadratically with xx in the range 0 << xx \lesssim 0.3, exhibits a kink at xx \approx 0.3, and then decreases linearly with xx in the range 0.3 \lesssim xx \lesssim 0.6. The behavior of Hc2(x,0)H_{c2}(x,0) appears to be due to pair breaking caused by the applied magnetic field and the exhange field associated with the polarization of the Nd magnetic moments, in the superconducting state. From magnetic susceptibility measurements, the correlations between the Nd moments in the superconducting state appear to change from ferromagnetic in the range 0.3 \lesssim xx \lesssim 0.6 to antiferromagnetic in the range 0 << xx \lesssim 0.3. Specific heat measurements on a sample with xx == 0.45 indicate that magnetic order occurs in the superconducting state, as is also inferred from the depression of Hc2(x,0)H_{c2}(x,0) with xx.Comment: 7 pages, 7 figures, currently submitted to Phys. Rev.

    Automatic Integral Reduction for Higher Order Perturbative Calculations

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    We present a program for the reduction of large systems of integrals to master integrals. The algorithm was first proposed by Laporta; in this paper, we implement it in MAPLE. We also develop two new features which keep the size of intermediate expressions relatively small throughout the calculation. The program requires modest input information from the user and can be used for generic calculations in perturbation theory.Comment: 23 page
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