Quasi-one-dimensional system as a high-temperature superconductor

It is well-known that quasi-one-dimensional superconductors suffer from the pairing fluctuations that significantly reduce the superconducting temperature or even completely suppress any coherent behavior. Here we demonstrate that a coupling to a robust pair condensate changes the situation dramatically. In this case the quasi-one-dimensional system can be a high temperature superconductor governed by the proximity to the Lifshitz transition at which the Fermi level approaches the lower edge of the single-particle spectrum.Comment: 5 pages, 1 figur

COMPARATIVE ANALYSIS OF THE EFFICIENCY OF THERMAL SYSTEMS BUILT WITH REFLECTIVE INSULATORS WITH AND WITHOUT VACUUM

The use of reflective surfaces functioning as thermal insulators has grown significantly over the years. Reflective thermal insulators are materials that have several characteristics such as low emissivity, low absorptivity and high reflectivity in the infrared spectrum. The use of these materials has grown very much lately, since they contain several important radioactive properties that minimize the heat loss of thermal systems and cooling systems that are used to block the heat on the roof of buildings. A system made of three surfaces of 430 stainless steel mirror was built to analyze the influence of reflective surfaces as a way to reduce the heat loss and thereby conserve the energy of a thermal system. The system was analyzed both with and without the presence of vacuum, and then compared with a system that contained glass wool between the stainless steel mirror walls, since this insulator is considered resistive and also broadly used around the world in thermal systems. The reflectivity and emissivity of the surfaces used were also measured in this experiment. A type K thermocouple was fixed on the wall of the system to obtain the temperature of the stainless steel mirror surfaces and to analyze the thermal behavior of each configuration used. The results showed an efficiency of 13% when the reflective surfaces were used to minimize the heat loss of the thermal system. However, the system with vacuum had the best outcome, a 60% efficiency. Both of these were compared to the system made of glass wool as a thermal insulator

Guandu Petrolina.

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Declínio e morte de plantas de videira.

Introdução. Aspectos da etiologia, taxonomia e biologia de agentes causadores. Sintomas. Disseminação. Parasitismo, sobrevivência e ambiente. Controle.bitstream/item/83248/1/doc082.pd

Custos de formação e manutenção de jardins clonais de cajueiro anão precoce.

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Fertilidade de ovelhas cíclicas submetidas à sincronização do estro utilizando implantes intravaginais (CIDR) novos ou reutilizados.

Edição dos Resumos XXII Reunião Anual da Sociedade Brasileira de Tecnologia de Embriões, Guarujá, SP, 2008

Electron localization by a magnetic vortex

We study the problem of an electron in two dimensions in the presence of a magnetic vortex with a step-like profile. Dependending on the values of the effective mass and gyromagnetic factor of the electron, it may be trapped by the vortex. The bound state spectrum is obtained numerically, and some limiting cases are treated analytically.Comment: 8 pages, latex, 4 figure

Two-dimensional electron gas in a uniform magnetic field in the presence of a delta-impurity

The density of states and the Hall conductivity of a two-dimensional electron gas in a uniform magnetic field and in the presence of a delta impurity are exactly calculated using elementary field theoretic techniques. Although these results are not new, our treatment is explicitly gauge-invariant, and can be easily adapted to other problems involving a delta potential.Comment: 12+1 pages, 1 ps figure, REVTEX. Corrigendum adde