DC-Bias-Superposition Characteristics of Ni0.4Zn0.2Mn0.4Fe2O4 Nanopowders Synthesized by Auto-Combustion

Ni0.4Zn0.2Mn0.4Fe2O4 nanopowders were prepared by auto-combustion method. The as-synthesized powders were characterized using X-ray diffraction (XRD) and thermo-gravimetric-differential thermal analysis (TG-DTA), and the powders were densified at different temperatures 400 degrees C, 500 degrees C, 600 degrees C and 700 degrees C/4 hrs using conventional sintering method. The sintered samples were characterized by XRD and transmission electron microscope (TEM). The bulk densities of the samples were increased with an increase of sintering temperature. The grain sizes of all the samples vary in between 18 nm to 30 nm. The hysteresis loops show high saturation magnetization and low coercivity, indicates that it is a soft material. The incremental permeability (permeability with magnetic field superposition) was influenced by both Delta M and H-c. A sample with higher initial permeability and favoured the attainment of a higher incremental permeability. The Q-factor was mainly determined by the sintered density and microstructure. To summarize, a uniform and dense microstructure with relatively small average grain size is favourable for obtaining better dc-bias-superposition characteristics, including permeability and Q-factor.

One pot auto-ignition based synthesis of novel Sr2CeO4: Ho3+ nanophosphor for photoluminescent applications

Ho3+ (0.25-7 mol%) doped Sr2CeO4 nanophosphors were synthesized by solution combustion method using urea as fuel. The structural properties of the nanophosphors were investigated by powder X-ray diffraction studies (PXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. UV-Visible and photoluminescence (PL) spectroscopic techniques were used for analysing the optical properties of the nanoparticles. PXRD and TEM results revealed the formation of Sr2CeO4: Ho3+ nanocrystalline particles with orthorhombic crystal structure. From the UV-Vis studies the optical band gap energy found to decrease from 5.9 to 5.74 eV with increase in dopant concentration. The PL spectra exhibit the broad excitation band from 200 to 400 nm which concurs well with the commercial near UV LED. The PL spectra vary with the dopant content due to energy transfer from the host to the activator. In this present work we demonstrate that color tuning of phosphor can be achieved by merely varying the Ho3+ ions concentration. The CIE and CCT chromaticity coordinates suggests Sr2CeO4: Ho3+ nanophosphors may be potentially applicable as promising single - phased phosphors for lighting applications. (C) 2015 Elsevier B.V. All rights reserved.

Un caso de auto-reescritura : El astrólogo fingido de Calderón

Resumen: La pulcra edición de la Segunda parte de comedias de Pedro Calderón de la Barca por Santiago Fernández Mosquera (Biblioteca Castro, 2007) y la reciente tesis de Fernando Rodríguez-Gallego (2009) sobre las dos versiones de El astrólogo fingido (Zaragoza, 1632 y Madrid, 1637) obligan hoy a una revisión de uno de los casos, tan frecuentes en la producción del dramaturgo madrileño, de reescritura —con miras esta vez a la publicación impresa— de una de sus obras. El examen se centrará, más allá de consideraciones formales y estéticas, en la valoración del alcance ético de las profundas transformaciones sufridas por el personaje del primer protagonista, el falso astrólogo, don Diego de Luna, así como en el análisis de las dos versiones del desenlace.

Criação de uma justiça auto-sustentável no Brasil

Consultoria Legislativa - Área I - Direito Constitucional, Eleitoral, Municipal, Direito Administrativo, Processo Legislativo e Poder Judiciário.