Search results for "BAND"
showing 10 items of 2610 documents
Alocucion de ... Pio ... VI tenida en el Consistorio secreto dia 13 de Noviembre 1775 de la preciosa muerte de Jacinto Castañeda español i Vicente …
1775
Corren exemplars sense port., que comencen amb una carta introductòria de Fr. Francisco Ruiz, Provincial de la Província d'Aragó i que inclouen, al verso de la p. 11, una oració del dit Provincial Escut xil. de Pius VI en les dues port. enfrentades Sign.: [ ]8 Notes a peu de pàg Reclams Doble port., en llatí i en castellà, i text bilingüe a dues col.: llatí i castellà
Reference-Plane Invariant Method for Measuring Electromagnetic Parameters of Materials
2010
This paper presents a simple and effective wideband method for the determination of material properties, such as the complex index of refraction and the complex permittivity and permeability. The method is explicit (non-iterative) and reference-plane invariant: it uses a certain combination of scattering parameters in conjunction with group-velocity data. This technique can be used to characterize both dielectric and magnetic materials. The proposed method is verified experimentally within a frequency range between 2 to 18 GHz on polytetrafluoroethylene and polyvinylchloride samples. A comprehensive error and stability analysis reveals that, similar to other methods based on transmission/re…
Improvement of the P/E window in nanocrystal memories by the use of high-k materials in the control dielectric
2005
Abstract In this paper nanocrystals memories program curves are shown and their saturation points (steady state condition) can be observed. We present a model that relates the voltage shift at the steady state ( Δ V T ss ) to the gate program voltage (VG). Starting from a good agreement between experimental data and simulations for nanocrystals memory cells with a conventional dielectric structure (SiO2), we present the estimated values of the Δ V T ss vs VG for different control stacks. Our investigation shows an improvement if a material with a high dielectric constant and a small conduction band-offset with respect to the SiO2, is placed between two SiO2 layers when the first of them is …
Zero permeability and zero permittivity band gaps in 1D metamaterial photonic crystals
2007
We consider layered heterostructures combining ordinary positive index materials and dispersive metamaterials. We show that these structures can exhibit a new type of photonic gap around frequencies where either the magnetic permeability \mu or the electric permittivity \epsilon of the metamaterial is zero. Although the interface of a semi-infinite medium with zero refractive index (a condition attained either when \mu= 0 or when \epsilon= 0) is known to give full reflectivity for all incident polarizations, here we show that a gap corresponding to \mu = 0 occurs only for TE polarized waves, whereas a gap corresponding to \epsilon = 0 occurs only for TM polarized waves. These band gaps are …
Elargissement jurisprudentiel du domaine d'application de la responsabilité pénale des personnes morales
2003
International audience
Desigualdades de género y formación profesional : elecciones, abandono y expectativas.
2020
Este artículo tiene como objetivo analizar las desigualdades de género con relación a las motivaciones escolares a la hora de escoger un ciclo formativo de grado medio, las motivaciones del abandono femenino y las expectativas para después de la formación profesional. Se parte del contexto sociohistórico e institucional de la formación profesional en España, del marco teórico de las elecciones escolares y de la perspectiva de género en la segregación laboral y educativa. A través del análisis del discurso de 12 jóvenes entrevistadas, se ha podido comprobar la persistencia de las desigualdades de género en la formación profesional, en las elecciones y las motivaciones y también se han encont…
Syndrome profiles in alcoholism and panic disorder with or without agoraphobia
2002
It is proposed that alcoholism and panic disorder/agoraphobia demonstrate in part common genetic and environmental origins. Shared subthreshold symptom patterns in the parents' generation could confirm the proposed genetic role in alcoholism and panic disorder/agoraphobia, even if the parents do not fulfil the diagnostic criteria for a primary psychiatric diagnosis. This is the first family study of exploratively analyzing subthreshold symptoms in both disorders. The authors investigated families with panic disorder/agoraphobia and/or alcoholism with the Munich-Composite International Diagnostic Interview (M-CIDI). We documented the diagnoses according to Diagnostic and Statistical Manual o…
Electronic structure and optical properties of CdTe rock-salt high pressure phase
2003
This paper reports on optical absorption and reflectance measurements in thin CdTe samples up to 15 GPa. All studied samples become virtually opaque at the pressure transition between the zinc-blende and rock-salt phases (3.9 GPa). As pressure increases up to 10 GPa, a relative transparency region is observed between 1.2 eV and 2.4 eV, whose high energy edge shifts to higher photon energies. Above 10 GPa the transparency region gradually shrinks and disappears at about 11 GPa. The low energy side of the absorption spectrum is attributed to free carrier absorption, as electronic structure calculations show that rock-salt CdTe is a semimetal or a low gap semiconductor. Band filling effects lo…
Pressure and temperature dependence of the band-gap in CdTe
2003
In this paper we report on isothermal compression measurements (up to 5 GPa and 500 K) of the optical absorption edge of 1 μm epitaxial layers of CdTe growth by metalorganic chemical vapor deposition (MOCVD) on GaS substrates. The isothermal blue shift under pressure of the direct energy gap (Γ v 15 → Γ c 1 ) in the zinc-blende phase is about 7.1 × 10 -2 eV GPa -1 and is found to be independent of temperature within the experimental errors. The isobaric red shift in the stability range of the zinc-blende phase is about -3.76 × 10 -4 eV K -1 . Regarding the phase transitions, no discontinuity in the energy gap has been found in the narrow pressure range where the cinnabar phase can be presen…
Tuning the band gap of PbCrO4 through high-pressure: Evidence of wide-to-narrow semiconductor transitions
2014
The electronic transport properties and optical properties of lead(II) chromate (PbCrO4) have been studied at high pressure by means of resistivity, Hall-effect, and optical-absorption measurements. Band-structure first-principle calculations have been also performed. We found that the low-pressure phase is a direct band-gap semiconductor (Eg = 2.3 eV) that shows a high resistivity. At 3.5 GPa, associated to a structural phase transition, a band-gap collapse takes place, becoming Eg = 1.8 eV. At the same pressure the resistivity suddenly decreases due to an increase of the carrier concentration. In the HP phase, PbCrO4 behaves as an n-type semiconductor, with a donor level probably associat…