Relativistic effects of mixed vector-scalar-pseudoscalar potentials for fermions in 1+1 dimensions

The problem of fermions in the presence of a pseudoscalar plus a mixing of vector and scalar potentials which have equal or opposite signs is investigated. We explore all the possible signs of the potentials and discuss their bound-state solutions for fermions and antifermions. The cases of mixed vector and scalar Poschl-Teller-like and pseudoscalar kink-like potentials, already analyzed in previous works, are obtained as particular cases.

Klein-Gordon particles in mixed vector-scalar inversely linear potentials

The problem of a spinless particle subject to a general mixing of vector and scalar inversely linear potentials in a two-dimensional world is analyzed. Exact bounded solutions are found in closed form by imposing boundary conditions on the eigenfunctions which ensure that the effective Hamiltonian is Hermitian for all the points of the space. The nonrelativistic limit of our results adds a new support to the conclusion that even-parity solutions to the nonrelativistic one-dimensional hydrogen atom do not exist. (c) 2005 Elsevier B.V. All rights reserved.

Confinement of fermions by mixed vector-scalar linear potentials in two-dimensional space-time

The problem of confinement of fermions in 1 + 1 dimensions is approached with a linear potential in the Dirac equation by considering a mixing of Lorentz vector and scalar couplings. Analytical bound-states solutions are obtained when the scalar coupling is of sufficient intensity compared to the vector coupling. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Bound states of the Duffin-Kemmer-Petiau equation with a mixed minimal-nonminimal vector cusp potential

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In vitro antibacterial action of Tetraclean, MTAD and five experimental irrigation solutions

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nonautonomous mixed mKdV-sinh-Gordon hierarchy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A class of mixed integrable models

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Structural studies on lead-cadmium fluoride solid solutions

(1-x)PbF2-(x)CdF2 solid solutions (with 0.1 less than or equal to x less than or equal to 0.5) were obtained by hyper-quenching the melt. Structural characteristics have been studied by X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). A cubic solid solution was obtained in which the lattice parameter decreases with increasing CdF2 content. High anionic disorder was evidenced from EXAFS investigations, whereas cations remain in the FCC arrangement. Pb L-3-edge EXAFS results illustrate clearly the occurrence of CdxPb1-xF2 mixed crystals by the introduction of Cd atoms in the second Pb coordination shell. (C) 2002 Elsevier B.V. B.V. All rights reserved.

On Duffin-Kemmer-Petiau particles with a mixed minimal-nonminimal vector coupling and the nondegenerate bound-states for the one-dimensional inversely linear background

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Spectrophotometric study of binary and ternary systems involving metal ions and benzylidenepyruvates: Equilibria in aqueous solutions

The protonation of 4-dimethylaminobenzylidenepyruvate (DMBP) and 2-chloro-4-dimethylaminobenzylidenepyruvate (2-CI-DMBP) and their complex formation with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pb(II), Cd(II) and Al(III) have been studied by potentiometric and spectrophotometric methods at 25 °C and ionic strength 0.500 M, held with sodium perchlorate. The stability order found for 1 :1 complexes of both ligands is Al(III) > Cu(II) > Pb(II) > Ni(II) > Zn(II) > Co(II) > Cd(II) > Mn(II). The stability changes move in the same direction as the pKa of the ligands. The results are compared with literature values reported for metal ion pyruvate systems. Thermodynamic stabilities of ternary complexes formed in Cu(II)-B-L- systems, where B = 2,2′-bipyridyl (bipy), ethylenediamine or glycinate and L = DMBP or 2-CI-DMBP, were also determined. The Cu(bipy)L+ species are more stable than would be expected on purely statistical grounds. The importance of the :t system associated with bipy on the enhanced stability of its mixed ligand complexes is stressed. Analytical applications of the investigated ligands are outlined.

On the regularization of mixed complementarity problems

A variational inequality problem (VIP) satisfying a constraint qualification can be reduced to a mixed complementarity problem (MCP). Monotonicity of the VIP implies that the MCP is also monotone. Introducing regularizing perturbations, a sequence of strictly monotone mixed complementarity problems is generated. It is shown that, if the original problem is solvable, the sequence of computable inexact solutions of the strictly monotone MCP's is bounded and every accumulation point is a solution. Under an additional condition on the precision used for solving each subproblem, the sequence converges to the minimum norm solution of the MCP. Copyright © 2000 by Marcel Dekker, Inc.

On the solution of bounded and unbounded mixed complementarity problems

A reformulation of the bounded mixed complementarity problem is introduced. It is proved that the level sets of the objective function are bounded and, under reasonable assumptions, stationary points coincide with solutions of the original variational inequality problem. Therefore, standard minimization algorithms applied to the new reformulation must succeed. This result is applied to the compactification of unbounded mixed complementarity problems. © 2001 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint, a member of the Taylor & Francis Group.

Adhesion of real seal to human root dentin treated with different solutions

The aim of this study was to evaluate the effects of different irrigants on sealer-dentin bond strength when using Real Seal. Thirty single-rooted teeth were divided into 3 groups. In one group, the teeth were irrigated with 3 mL of 2.5% NaOCl after each file change, flushed with 17% EDTA for 3 min and finally rinsed with 3 mL of 2.5% NaOCl. In the other two groups, rinse with NaOCl was replaced with 2% chlorhexidine gluconate (CHX) and 0.9% saline, respectively. Each root was sectioned transversally into apical, middle and coronal thirds to obtain 2-mm-thick slices. Each slice was filled with Real Seal and Resilon. Push-out test was used to analyze bond strength and failure modes were classified as adhesive, cohesive or mixed, according to SEM observations. The push-out test did not reveal any statistically significant difference (p>0.05) between the irrigants. However, the groups exhibited significantly different (p<0.05) bond strengths in terms of the root canal third. Higher bond strength was observed at the apical third when compared with coronal third, while middle third presented intermediary values. Fifteen specimens were analyzed by SEM (5 per group). Eleven specimens exhibited adhesive failures (5 in saline, 4 in NaOCl and 2 in CHX group); 2 cohesive failures were observed in the CHX group, and 1 mixed failure each was observed in the CHX and NaOCl groups. The tested irrigants did not influence the bond strength of Resilon and Real Seal to dentin. The apical third exhibited higher mean bond strengths and adhesive failures were predominant.

Bilevel approach for optimal location and contract pricing of distributed generation in radial distribution systems using mixed-integer linear programming

In this study, a novel approach for the optimal location and contract pricing of distributed generation (DG) is presented. Such an approach is designed for a market environment in which the distribution company (DisCo) can buy energy either from the wholesale energy market or from the DG units within its network. The location and contract pricing of DG is determined by the interaction between the DisCo and the owner of the distributed generators. The DisCo intends to minimise the payments incurred in meeting the expected demand, whereas the owner of the DG intends to maximise the profits obtained from the energy sold to the DisCo. This two-agent relationship is modelled in a bilevel scheme. The upper-level optimisation is for determining the allocation and contract prices of the DG units, whereas the lower-level optimisation is for modelling the reaction of the DisCo. The bilevel programming problem is turned into an equivalent single-level mixed-integer linear optimisation problem using duality properties, which is then solved using commercially available software. Results show the robustness and efficiency of the proposed model compared with other existing models. As regards to contract pricing, the proposed approach allowed to find better solutions than those reported in previous works. © The Institution of Engineering and Technology 2013.

Scattering and bound states of fermions in a mixed vector-scalar smooth step potential

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)