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Relation between Luminescence and Electronic Surface Characteristics in p-type Porous Silicon
(1997)Measurements of photoluminescence, electronic surface states and effective surface area, at various stages of the anodization process, are presented. The results show a behavior different from that observed on n-type porous Si. -
Phototransport Properties of a-SiC:H Alloys
(1995)We report a study of the mobility-lifetime products of the two charge carriers in a-SiC:H alloys. The measurements were carried out as a function of the carbon concentration and the temperature. An analysis, relying on the ... -
Vacuum treatment to stabilize oxidation at low temperature region in porous silicon
(2020)Oxidation in porous silicon is studied for as-etched samples and samples subjected to high vacuum at room temperature. Attenuated Total Reflectance (ATR) measurements in infrared spectroscopy for temperatures ranging from ... -
Pressure dependence of ferroelectric quantum critical fluctuation
(2019-12-13)Phase transitions to a long-range-ordered state driven by a softened phonon mode are ubiquitous across condensed matter physics, but the evolution of such a mode as the system is tuned to or from the transition has never ... -
Exact solution of an ekpyrotic fluid and a primordial magnetic field in an anisotropic cosmological space-time of Petrov D
(2017)This document obtained and analyzed an exact solution of an ekpyrotic fluid (P = 5/3 µ) and a primordial magnetic field, so that the latter does not induce currents or electric fields. It is determined that the main role, ... -
Exact Solutions of a Chaplygin Gas in an Anisotropic Space-Time of Petrov D
(2017)This document obtains two exact solutions to the anisotropic spacetime of Petrov D by using the model of a perfect fluid. These solutions represent a scenario of a universe in which the pressure P and the energetic density ... -
A study of a coronal hole associated with a large filament eruption
(2017)We report the results of a detailed study of an equatorial coronal hole and a dimming region related to the eruptions of a nearby large filament and subsequent coronal mass ejections (CMEs). The dynamic eruptions of the ... -
Do Magnetic Fields Destroy Black Hole Accretion Disk g-Modes?
(2015-08-04)Diskoseismology, the theoretical study of normal-mode oscillations in geometrically thin, optically thick accretion disks, is a strong candidate for explaining some quasi-periodic oscillations in the power spectra of many ... -
Study of oxide bands in p-type porous silicon layers
(2019)The interest in developing fast and reliable chemical and biochemical sensors in an inexpensive way is something that has attracted a lot of efforts in the last decades. One of the potential material candidates is ... -
Quantum Ferroelectric Instabilities in Superconducting SrTiO3
(2018)We examine the effects of strain and cation substitution on the superconducting phase of polar semiconductors near a ferroelectric quantum phase transition with a model that combines a strong coupling theory of ... -
Negative Thermal Expansion in Open Perovskites near the Precipice of Structural Stability
(2018)Negative thermal expansion (NTE) describes the anomalous propensity of materials to shrink when heated. Since its discovery, the NTE effect has been found in a wide variety of materials with an array of magnetic, electronic ... -
The Hubble Constant and the Deceleration Parameter in Anisotropic Cosmological Spaces of Petrov type D
(2016-11)In this paper the Hubble parameter and the deceleration parameter are analyzed for a group of anisotropic homogeneous solutions of the Petrov type-D. It is obtained that for the said set of solutions can be constructed a ... -
Cosmological Exact Solutions Set of a Perfect Fluid in an Anisotropic Space-Time in Petrov Type D
(2016-06)In this document a set of exact solutions is obtained by using the model of a perfect fluid on an homogeneous and anisotropic space-time that belongs to (Local Rotational Symmetry) Petrov’s type D. This solutions represent ... -
The gigaelectronvolt counterpart of ver j2019+407 in the northern shell of the supernova remnant g78.2+2.1 (γ cygni)
(2016-07)Analysis of gamma-ray emission from the supernova remnant G78.2+2.1 (γ Cygni) with 7.2 years of cumulative data from the Fermi Large Area Telescope shows a distinct hard, bright, and extended component to the north of the ... -
(Hydro)climatological studies of climate change and variability in Central America
(2018-06-26)This is the presentation of Hugo Hidalgo at the CORDEX Central America and South America Training Workshop on Downscaling Techniques, in La Paz, Bolivia, June 25 to 27, 2018. -
Search for gamma-ray emission from star-forming galaxies with Fermi LAT
(2016-08)Recent studies have found a positive correlation between the star-formation rate of galaxies and their gamma-ray luminosity. Galaxies with a high star-formation rate are expected to produce a large amount of high-energy ... -
Irreversibility of mechanical and hydrodynamic instabilities
(2017-12-01)The literature on dynamical systems has, for the most part, considered self-oscillators (i.e., systems capable of generating and maintaining a periodic motion at the expense of an external energy source with no corresponding ... -
Observed Changes (1970-1999) in Extreme Hydroclimatic Events in Central America
(2018-04-20)Previous studies have shown that most of Central America has been experiencing warming trends during the last 30-50 years, while precipitation annual totals have not changed much. Warming alone can exacerbate the effects ... -
Interaction of a quantum field with a rotating heat bath
(2018-08-01)The linear coupling of a rotating heat bath to a quantum field is studied in the framework of the Markovian master equation for the field's non-unitary time evolution. The bath's rotation induces population inversion for ...
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