Search results for "RAM"
showing 10 items of 35643 documents
Signal processing in photonic crystals and nanostructures
2006
International audience; Optical devices employing photonic crystals and novel nanostructure materials may exhibit useful properties for applications to all-optical signal processing. In this work we analyze as a first example four-wave mixing of polarized beams in photonic crystal fibers. We show that by properly tuning the pump wavelength and the linear dispersion properties of the fiber one may obtain broadband parametric amplification and frequency conversion. Next we consider the in-line periodic amplification of short optical pulses by means of quantum-dot semiconductor optical amplifiers. We show by numerical simulations that pattern-free amplification of a 40 Gbit/s soliton signal at…
Donor-π-acceptors containing the 10-(1,3-dithiol-2-ylidene)anthracene unit for dye-sensitized solar cells
2012
Two donor-acceptor molecular tweezers incorporating the 10-(1,3-dithiol-2-ylidene)anthracene unit as donor group and two cyanoacrylic units as accepting/anchoring groups are reported as metal-free sensitizers for dye-sensitized solar cells. By changing the phenyl spacer with 3,4-ethylenedioxythiophene (EDOT) units, the absorption spectrum of the sensitizer is red-shifted with a corresponding increase in the molar absorptivity. Density functional calculations confirmed the intramolecular charge-transfer nature of the lowest-energy absorption bands. The new dyes are highly distorted from planarity and are bound to the TiO(2) surface through the two anchoring groups in a unidentate binding for…
Synthesis, Optical, and Morphological Studies of ZnO Powders and Thin Films Fabricated by Wet Chemical Methods
2020
Zinc oxide nanoparticles were prepared from Zn5(CO3)2(OH)6 precursor, capped with poly(vinylpyrrolidone) (PVP), and annealed at 600 °
Influence of PDA Coating on the Structural, Optical and Surface Properties of ZnO Nanostructures
2020
Polydopamine (PDA) is a new biocompatible material, which has prospects in biomedical and sensor applications. Due to functional groups, it can host wide range of biomolecules. ZnO nanostructures are well known templates for optical sensors and biosensors. The combination of ZnO and PDA results in a change of optical properties of ZnO&ndash
Comparison between unrestricted dynamic shakedown design and a new probabilistic approach for structures under seismic loadings
2014
The paper concerns a study related to the comparison between two different approaches utilized for the formulation of an optimal shakedown design problem for elastic plastic frame structures subjected to a combination of fixed and seismic loading. The first formulation utilizes the unrestricted dynamic shakedown theory, while the second one is based on a new probabilistic approach. The comparison is effected in terms of mathematical formulations, in terms of adopted loading models and in terms of numerical results. The performed applications are related to plane steel frames.
Models and algorithms for berth allocation problems in port terminals
2017
Seaports play a key role in maritime commerce and the global market economy. Goods of different kinds are carried in specialized vessels whose handling requires ad hoc port facilities. Port terminals comprise the quays, infrastructures, and services dedicated to handling the inbound and outbound cargo carried on vessels. Increasing seaborne trade and ever-greater competition between port terminals to attract more traffic have prompted new studies aimed at improving their quality of service while reducing costs. Most terminals implement operational planning to achieve more efficient usage of resources, and this poses new combinatorial optimization problems which have attracted increasing att…
Fundamentos de Optimización Matemática en Economía
1999
La optimización matemática es un área dentro de las matemáticas que se encarga de la elección de la mejor alternativa de entre las posibles para un problema formulado en términos matemáticos. Este área de las matemáticas es muy amplia, debido a la diversidad de situaciones que se pueden plantear y a las distintas maneras de enfocar la resolución del problema. El presente texto, en la medida que pretende ser una herramienta para el análisis económico, se centra en la programación no lineal y en los métodos analíticos de resolución de esos problemas. Por tanto, el objetivo es proporcionar al lector los conocimientos básicos y avanzados de optimización matemática que destacan por su aplicabili…
Fotogrammetrijas metode mikrofosīliju 3D modeļu izveidei
2019
Ješkins J. 2019. Fotogrammetrijas metode mikrofosīliju 3D modeļu izveidei. Maģistra darbs. Pētījuma mērķis ir izstrādāt mikrofosīliju 3D rekonstrukcijas metodi, izmantojot fotogrammetrijas principu. Autors piedāvā inovatīvu 3D modeļu izveides metodi, pielietojot attēlu iegūšanu ar optiskās mikroskopijas palīdzību un attēlu fotogrammetrisko apstrādi. Izstrādātā metode ir aprobēta uz dažāda vecuma, izmēra, minerālā un ķīmiskā sastāva mikrofosīlijām, un tiek rekomendēta kā alternatīva esošajām metodēm. Izstrādāta metode var tikt pielietota zinātniskiem nolūkiem pētnieku komandās, kurām nav pieejamas citas, komplicētas un dārgas metodes 3D rekonstrukciju veikšanai. Pētījuma diskusijā autors pie…
An Oral History of Programming Practices: Gender and Age Dynamics and Digital (Dis)Engagement Among Computer Programmers in Finland
2015
Since the 1980s, educational policies in many countries have aimed at improving the computer literacy and programming competencies of the population. Over the same period, the possibilities that people have seen regarding programming and everyday programming practices have emerged as an area of strong interest within historical scholarship. The paper contributes to these discussions by drawing on techniques of oral history to focus on programming hobbies and practices in Finland. Examining data from a massive survey of computer hobbyists (N = 1,453) and their recollections about personal computer use (largely during the 1980s), the paper gathers new information on what leads to people’s pur…
Scheda 397. Anello con monogramma a croce
2008
scheda scientifica di anello in bronzo con monogramma a croce inciso sul castone, sec. VI-IX d. C., Museo Archeologico di Palermo