Search results for "lcsh:P"
showing 10 items of 4419 documents
Hacia una propuesta metodológica para el estudio de la atenuación fónica en Es.Var.Atenuación
2017
espanolEl proyecto Es.Var.Atenuacion se interesa por el estudio de la atenuacion pragmatica a nivel linguistico, estructural, enunciativo y situacional, en corpus discursivos del espanol, a fin de reconocer las posibles estrategias atenuantes de un acto comunicativo. Para llevar a cabo el analisis se parte de una ficha de trabajo (Briz y Albelda, 2013. Una propuesta teorica y metodologica para el analisis de la atenuacion linguistica en espanol y portugues. La base de un proyecto comun (ES. POR.ATENUACION). Onomazein, 28, pp. 288–319; Albelda, Briz, Cestero, Kotwica y Villalba, 2014. Ficha metodologica para el analisis pragmatico de la atenuacion en corpus discursivos del espanol. (ES.POR.A…
Historia de las madres en occidente: repensar la maternidad
2005
El objetivo del presente trabajo es profundizar sobre la historia de la concepción de la maternidad, enmarcándola como un proceso evolutivo y vital propio del desarrollo psicobiológico humano, pero con características diferentes en cada etapa histórica. Ser madre en la especie humana excede el hecho biológico y tiene un significado a nivel social, cultural, histórico y psicológico. Dos fenómenos han influído fuertemente a partir de la segunda mitad del Siglo XX - en la historia de la maternidad: los estados de bienestar,-especialmente en los países desarrollados- y el crecimiento de las ciencias biológicas en relación a la posibilidad a planificar los nacimientos. La maternidad recorre el c…
Validación del Autoconcepto Forma 5 en Universitarios Peruanos: Una Herramienta para la Psicología Positiva
2015
ResumenEl autoconcepto, aunque central en la psicología tradicional, ha cobrado importancia recientemente en el contexto de la psicología positiva. El Autoconcepto Forma 5 (AF5) es una medida muy utilizada en el contexto hispanohablante. Sin embargo, no existen estudios sobre sus propiedades psicométricas más allá de la fiabilidad en población peruana. El objetivo es presentar las propiedades psicométricas de la escala multidimensional AF5 en universitarios peruanos. Se recogió una muestra de 527 estudiantes universitarios. La encuesta incluyó, además del AF5, medidas de esperanza disposicional y satisfacción con la vida. Se llevó a cabo un análisis factorial confirmatorio para evaluar la v…
A half-metallic half-Heusler alloy having the largest atomic-like magnetic moment at optimized lattice constant
2016
For half-Heusler alloys, the general formula is XYZ, where X can be a transition or alkali metal element, Y is another transition metal element, typically Mn or Cr, and Z is a group IV element or a pnicitide. The atomic arrangements within a unit-cell show three configurations. Before this study, most of the predictions of half-metallic properties of half-Heusler alloys at the lattice constants differing from their optimized lattice constant. Based on the electropositivity of X and electronegativity of Z for half-Heusler alloys, we found that one of the configurations of LiCrS exhibits half-metallic properties at its optimized lattice constant of 5.803Å, and has the maximum atomic-like magn…
Determination of fine magnetic structure of magnetic multilayer with quasi antiferromagnetic layer by using polarized neutron reflectivity analysis
2020
We carried out polarized neutron reflectivity (PNR) analysis to determine the fine magnetic structure of magnetic multilayers with quasi-antiferromagnetic (quasi-AFM) layers realized by 90-deg coupling using two Co90Fe10 layers, and quantitatively evaluated the magnetization of quasi-AFM layers. Two types of samples with different buffer layers, Ru buffer and a NiFeCr buffer, were investigated and the average angles between the respective magnetization of the two Co90Fe10 layers were estimated to be +/− 39 degrees and +/− 53 degrees. In addition, less roughness was found in the NiFeCr buffer sample resulting stronger 90-deg coupling. A perfect quasi-AFM is expected to be realized by a flat …
Ptychographic imaging and micromagnetic modeling of thermal melting of nanoscale magnetic domains in antidot lattices
2020
CA extern Antidot lattices are potential candidates to act as bit patterned media for data storage as they are able to trap nanoscale magnetic domains between two adjacent holes. Here, we demonstrate the combination of micromagnetic modeling and x-ray microscopy. Detailed simulation of these systems can only be achieved by micromagnetic modeling that takes thermal effects into account. For this purpose, a Landau-Lifshitz-Bloch approach is used here. The calculated melting of magnetic domains within the antidot lattice is reproduced experimentally by x-ray microscopy. Furthermore, we compare conventional scanning transmission x-ray microscopy with resolution enhanced ptychography. Hence, we …
Outstanding nonlinear optical properties of methylammonium- and Cs-PbX3 (X = Br, I, and Br–I) perovskites: Polycrystalline thin films and nanoparticl…
2019
Metal Halide Perovskites (MHPs) have arisen as promising materials to construct cost-effective photovoltaic and light emission devices. The study of nonlinear optical properties of MHPs is necessary to get similar success in nonlinear photonic devices, which is practically absent in the literature. The determination of the third order nonlinear coefficients is typically done by the Z-scan technique, which is limited by the scattering of polycrystalline thin films. In this work, we have studied nonlinear optical properties of polycrystalline CH3NH3PbX3 (MAPbX3) thin films and colloidal CsPbX3 nanoparticles with three different bandgaps (X3 = I3, Br3, and Br1.5I1.5). Their bright generation o…
On the solution of a parabolic PDE involving a gas flow through a semi-infinite porous medium
2021
Abstract Taking as start point the parabolic partial differential equation with the respective initial and boundary conditions, the present research focuses onto the flow of a sample of waste-water derived from a standard/conventional dyeing process. In terms of a highly prioritized concern, meaning environment decontamination and protection, in order to remove the dyes from the waste waters, photocatalyses like ZnO or TiO2 nanoparticles were formulated, due to their high surface energy which makes them extremely reactive and attractive. According to the basics of ideal fluid, the key point is the gas flow through an ideal porous pipe consisting of nanoparticles bound one to each other, for…
Effect of nanostructure layout on spin pumping phenomena in antiferromagnet/nonmagnetic metal/ferromagnet multilayered stacks
2017
In this work we focus on magnetic relaxation in Mn80Ir20(12 nm)/Cu(6 nm)/Py(dF) antiferromagnet/Cu/ferromagnet (AFM/Cu/FM) multilayers with different thickness of the ferromagnetic permalloy layer. An effective FM-AFM interaction mediated via the conduction electrons in the nonmagnetic Cu spacer – the spin-pumping effect – is detected as an increase in the linewidth of the ferromagnetic resonance (FMR) spectra and a shift of the resonant magnetic field. We further find experimentally that the spin-pumping-induced contribution to the linewidth is inversely proportional to the thickness of the Py layer. We show that this thickness dependence likely originates from the dissipative dynamics of …
Dynamics of quantum discord of two coupled spin-1/2’s subjected to time-dependent magnetic fields
2019
Abstract We describe the dynamics of quantum discord of two interacting spin-1/2’s subjected to controllable time-dependent magnetic fields. The exact time evolution of discord is given for various input mixed states consisting of classical mixtures of two Bell states. The quantum discord manifests a complex oscillatory behaviour in time and is compared with that of quantum entanglement, measured by concurrence. The interplay of the action of the time-dependent magnetic fields and the spin-coupling mechanism in the occurrence and evolution of quantum correlations is examined in detail.