1,832 research outputs found

    The Solution of the Relativistic Schrodinger Equation for the δ\delta'-Function Potential in 1-dimension Using Cutoff Regularization

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    We study the relativistic version of Schr\"odinger equation for a point particle in 1-d with potential of the first derivative of the delta function. The momentum cutoff regularization is used to study the bound state and scattering states. The initial calculations show that the reciprocal of the bare coupling constant is ultra-violet divergent, and the resultant expression cannot be renormalized in the usual sense. Therefore a general procedure has been developed to derive different physical properties of the system. The procedure is used first on the non-relativistic case for the purpose of clarification and comparisons. The results from the relativistic case show that this system behaves exactly like the delta function potential, which means it also shares the same features with quantum field theories, like being asymptotically free, and in the massless limit, it undergoes dimensional transmutation and it possesses an infrared conformal fixed point.Comment: 32 pages, 5 figure

    Functionalized crystalline polyactones as toughners for thermosetting resins

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    A crystalline polylactone is produced having reactive acrylate end groups. When incorporated into a thermosetting resin which includes reactive C.dbd.CH.sub.2 sites, the present functionalized polylactone acts as a toughener, greatly increasing the impact resistance of the final cured product. Also disclosed are carboxyl-bearing polylactones as tougheners for epoxy resin systems

    Relationship of sea level muon charge ratio to primary composition including nuclear target effects

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    The discrepancy between the muon charge ratio observed at low energies and that calculated using pp data is removed by including nuclear target effects. Calculations at high energies show that the primary iron spectrum is expected to change slope from 2 to 2.2 to 2.4 to 2.5 for energies approx. 4 x 10 to the 3 GeV/nucleon if scaling features continue to the highest energies

    Degradation of Polymeric Biomaterials

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    Environmental and processing factors affecting the biostability of medical devices made from traditionally stable polymers, such as isotactic polypropylene (PP) and ultrahigh molecular weight polyethylene (UHMW-PE) , were analyzed and their undesirable degradation was related to performance of typical medical devices. Among the critical phenomena determining the biological performance of UHMW-PE and PP devices are oxidation during melt-processing and the propensity of the polymer chains to radiolyse and radio-oxidize. Polyesters and their biomedical devices , which can be designed to degrade predictably, are addressed with some focus on the less obvious determinants of performance

    Fate of Accidental Symmetries of the Relativistic Hydrogen Atom in a Spherical Cavity

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    The non-relativistic hydrogen atom enjoys an accidental SO(4)SO(4) symmetry, that enlarges the rotational SO(3)SO(3) symmetry, by extending the angular momentum algebra with the Runge-Lenz vector. In the relativistic hydrogen atom the accidental symmetry is partially lifted. Due to the Johnson-Lippmann operator, which commutes with the Dirac Hamiltonian, some degeneracy remains. When the non-relativistic hydrogen atom is put in a spherical cavity of radius RR with perfectly reflecting Robin boundary conditions, characterized by a self-adjoint extension parameter γ\gamma, in general the accidental SO(4)SO(4) symmetry is lifted. However, for R=(l+1)(l+2)aR = (l+1)(l+2) a (where aa is the Bohr radius and ll is the orbital angular momentum) some degeneracy remains when γ=\gamma = \infty or γ=2R\gamma = \frac{2}{R}. In the relativistic case, we consider the most general spherically and parity invariant boundary condition, which is characterized by a self-adjoint extension parameter. In this case, the remnant accidental symmetry is always lifted in a finite volume. We also investigate the accidental symmetry in the context of the Pauli equation, which sheds light on the proper non-relativistic treatment including spin. In that case, again some degeneracy remains for specific values of RR and γ\gamma.Comment: 27 pages, 7 figure

    Degradation of Polymeric Biomaterials

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    Environmental and processing factors affecting the biostability of medical devices made from traditionally stable polymers, such as isotactic polypropylene (PP) and ultrahigh molecular weight polyethylene (UHMW-PE) , were analyzed and their undesirable degradation was related to performance of typical medical devices. Among the critical phenomena determining the biological performance of UHMW-PE and PP devices are oxidation during melt-processing and the propensity of the polymer chains to radiolyse and radio-oxidize. Polyesters and their biomedical devices , which can be designed to degrade predictably, are addressed with some focus on the less obvious determinants of performance
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