Search results for "Solid"
showing 10 items of 3575 documents
Ge quantum well plasmon-enhanced quantum confined Stark effect modulator
2014
ABSTRACTWe theoretically and experimentally investigate a novel modulation concept on silicon (Si) based on the combination of quantum confinement and plasmon enhancement effects. We experimentally study the suitability of Ge/SiGe quantum wells (QWs) on Si as the active material for a plasmon-enhanced optical modulator. We demonstrate that in QW structures absorption and modulation of light with transverse magnetic (TM) polarization are greatly enhanced due to favorable selection rules. Later, we theoretically study the plasmon propagation at the metal-Ge/SiGe QW interface. We design a novel Ge/SiGe QW structure that allows maximized overlap between the plasmonic mode and the underlying Ge/…
Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition.
2013
A study of transmittance and photoluminescence spectra on the growth of oxygen-rich ultra-thin ZnO films prepared by atomic layer deposition is reported. The structural transition from an amorphous to a polycrystalline state is observed upon increasing the thickness. The unusual behavior of the energy gap with thickness reflected by optical properties is attributed to the improvement of the crystalline structure resulting from a decreasing concentration of point defects at the growth of grains. The spectra of UV and visible photoluminescence emissions correspond to transitions near the band-edge and defect-related transitions. Additional emissions were observed from band-tail states near th…
Effects of non-tracking solar collector orientation on energy production : photovoltaic systems
2012
Abstract: This Master's thesis proposes a new method for calculating the optimum tilt and orientation angle of a fitted solar collector. In addition to using geographical data, this method takes into account the radiation data and weather statistics of prospective locations. This makes the calculations valid not only for certain latitudes, but also for certain radiation and weather conditions. Calculations were done by estimating the energy production of a given solar array using a sequence of different tilt angles and orientation angles. Special attention was given to shaded solar arrays and arrays made up of photovoltaic modules. Specific radiation and weather data was used for both locat…
Innovative Approaches for Light-Emitting Electrochemical Cells
2023
El uso de nuevos materiales, como las moléculas emisoras de luz o los polímeros transportadores de iones, tiene una importancia fundamental a la hora de mejorar la vida útil o de conseguir altos niveles de luminancia en dispositivos de tipo LEC. Al mismo tiempo, los avances más recientes han llevado a la tecnología LED y OLED a una nueva clase de dispositivos con propiedades atractivas, como la flexibilidad o la transparencia, desarrollo que se ha llevado a cabo de forma muy limitada en los LECs. Teniendo esto en cuenta, el trabajo de esta Tesis se centró en la implementación de nuevos materiales, en particular nuevos emisores iTMC y un polímero conductor iónico, y el diseño y fabricación d…
4,4'-[Thiophene-2,5-diylbis(ethyne-2,1-diyl)]dibenzonitrile
2008
In the solid state, the title compound, C(22)H(10)N(2)S, forms centrosymmetric dimers by pairs of non-classical C-H⋯S hydrogen bonds linking approximately coplanar mol-ecules. The benzene ring involved in this inter-action makes a dihedral angle of only 7.21 (16)° with the thio-phene ring, while the other benzene ring is twisted somewhat out of the plane, with a dihedral angle of 39.58 (9)°. The hydrogen-bonded dimers stack on top of each other with an inter-planar spacing of 3.44 Å. C-H⋯N hydrogen bonds link together stacks that run in approximately perpendicular directions. Each mol-ecule thus inter-acts with 12 adjacent mol-ecules, five of them approaching closer than the sum of the van …
Ideas for using GeoGebra and Origami in Teaching Regular Polyhedrons Lessons
2018
The approach of combining GeoGebra and origami is well accepted among students in the school "Petro Kuzmjak" where it is used to teach geometry lessons. This article elaborates on how to introduce students (upper elementary and high school students, age 14-18) to Platonic solids and their properties through combination of GeoGebra and origami activities. Some of the important mathematical concepts related to these well-known geometrical solids can be explained to students applying hands-on activities along with educational software. peerReviewed
New experimental tools for the characterization of highly overconsolidated clayey materials in unsaturated conditions
2010
This chapter presents some of the experimental facilities that have recently been developed at the EPFL Soil Mechanics Group. Three apparatuses operating in non-isothermal conditions are described in detail: a sorption bench for determining water retention curves, an oedometric cell for analyzing volumetric responses under high vertical loads, and a triaxial cell designed for extreme loading conditions.
Statistical analyses on the essential oil of italian coriander (coriandrum sativum L.) fruits of different ages and origins
2002
Thirty-one samples of Coriandrum sativum L. fruits, of different origin, year of cultivation (harvest) and crop management systems were subjected to volatile component analysis by combining Head Space Solid Phase Microextraction (HS-SPME) with GC/MS. In order to determine the importance of the major sources of volatile variability, some statistical analyses, including Cluster Analysis (CA) and Principal Component Analysis (PCA), were performed on the obtained data. The compounds, which gave the main contribution to the partition and classification of the original data, were α-pinene, p-cymene, γ-terpinene and linalool. The age of the fruits, which ranged from 1–16 years, seemed to generate …
UV filters: From sunscreens to human body and the environment
2007
Recognition of the harmful effects of ultraviolet (UV) radiation on the skin has triggered development of organic chemicals (commonly referred as UV filters) that can absorb UV radiation and attenuate the negative effects of sunlight exposure. Depending on the properties and the intended degree of protection, a wide array of combinations is being marketed as delivering protection against most kinds of UV-induced skin damage. However, some UV filters have dermatological implications, so maximum applicable concentrations have been established. To monitor to what extent commercial products comply with the mandatory limits, several analytical methods have been used for their determination in co…
Il progetto di Giuseppe Patricolo per il restauro ottocentesco del “soffitto monumentale”
2020
Lo studio esamina il cantiere di restauro del soffitto monumentale di palazzo Chiaramonte, riconoscendolo come un episodio importante per Palermo e per la lunga storia delle trasformazioni del palazzo trecentesco, una storia di scoperte, collaborazioni e progetti di restauro che costituiscono il contributo essenziale per la comprensione del valore monumentale del soffitto ligneo decorato. Nel 1886 Camillo Boito visita Palermo come componente di una commissione governativa, composta anche da Felice Bernabei, Alfredo D’Andrade e Francesco Bongioannini e si pronuncia sull’annosa questione dei ripristini del palazzo Chiaromonte, sostenendo fortemente la candidatura di Giuseppe Patricolo come pr…