Search results for "Dispersion."

Structural studies of dielectric polymer nanocomposites

2013

A constant need for the development of new and superior materials is always present; for example, a better electrical insulator would enable more efficient use of electrical power. Polymeric nanocomposites, i.e. nanodielectrics, are thought to have unique electrical properties. The basic chemical constitution of a material alone fails to provide an understanding of how desired properties of a material originate or predict the long term behavior of a material. We need to define the structure behind the functionality of a material. To do that, the structure of the material must be studied on several scales. This research was part of the Finnish Funding Agency for Technology and Innovation (TE…

Computational Structures and SAPT Interaction Energies of HXeSH···H2Y (Y=O or S) Complexes

2018

Ab initio calculations of the structures, vibrational spectra and supermolecular and symmetry-adapted perturbation theory (SAPT) interaction energies of the HXeOH and HXeSH complexes with H2O and H2S molecules are presented. Two minima already reported in the literature were reproduced and ten new ones were found together with some transition states. All complexes show blue shift in Xe&ndash

Measurement of nonlinear and chromatic dispersion parameters of optical fibers using modulation instability

2006

International audience; We present a simple method for the measurement of Kerr, second- and third-order dispersion coefficients in optical fibers using power and dispersion dependences of modulation instability near the zero-dispersion wavelength. We also complete the analysis by the accurate determination of the zero-dispersion wavelength of the fiber using the phase-matched four wave mixing process which occurs near this specific wavelength.

Measurement of the soliton number in guiding media through continuum generation.

2020

No general approach is available yet to measure directly the ratio between chromatic dispersion and the nonlinear coefficient, and hence the soliton number for a given optical pulse, in an arbitrary guiding medium. Here we solve this problem using continuum generation. We experimentally demonstrate our method in polarization-maintaining and single-mode fibers with positive and negative chromatic dispersion. Our technique also offers new opportunities to determine the chromatic dispersion of guiding media over a broad spectral range while pumping at a fixed wavelength. (C) 2020 Optical Society of America

Simultaneous polarization attraction and Raman amplification of a light beam in optical fibers

2012

International audience; In this paper, we demonstrate that it is possible to combine both Raman amplification and polarization attraction of a signal wave in a single optical fiber by means of a counterpropagating scheme. Experiments were performed near 1550 nm in a continuous wave regime and by means of a 10 Gbit ∕ s return-to-zero signal injected in a 20 kmlong low polarization mode dispersion optical fiber. Complete repolarization and 6.7 dB amplification of the signal wave was achieved by injecting a 850 mW, 1480 nm counterpropagating polarized pump wave.

Estimating the safety performance function for urban unsignalized four-legged one-way intersections in Palermo, Italy

2014

Abstract Starting from consideration that urban intersections are sites with promise for safety and operational improvements, the paper describes the steps taken to develop a crash predictive model for estimating the safety performance of urban unsignalized intersections located in Palermo, Italy. The focus is on unsignalized four-legged one-way intersections widespread in Italian downtowns. The sample considered in the study consist of 92 intersections in Palermo, Italy. For the study were collected crashes occurred in the sites during the years 2006-2012, geometric design and functional characteristics and traffic flow. Results showed that data were overdispersed and NB1 distributed. In o…

Tra reale e virtuale: problematiche pedagogiche. Seminari e conversazioni

2009

Consumers' privacy, selling of information, and security in digital markets

2019

La era digital se caracteriza por la gran producción de datos (algunos de ellos de naturaleza privada) a gran escala. La vulnerabilidad y la exposición está ocurriendo a un ritmo sin precedentes, produciendo grandes incentivos económicos para los propietarios de estos datos. Sin embargo, los proveedores de dichos datos, que a menudo son consumidores de contenido gratuito en plataformas digitales, están comenzando a desarrollar problemas de privacidad y, por lo tanto, conducen a la consiguiente reducción de la confianza en los mercados digitales. El objetivo principal de esta tesis es analizar la privacidad desde una perspectiva informativa y fuente de ineficiencias en el mercado. Además, la…

Diffusione del punteruolo rosso delle palme a Palermo a tre anni dalla sua introduzione.

2009

L’orientamento nel primo biennio di un istituto professionale

2017

L’intervento mirava a verificare se, integrando l’azione della scuola, che è un’agenzia educativa formale, con quella di agenzie formative non formali che operano nello stesso territorio dell’Istituto professionale coinvolto nella ricerca, si abbassava il tasso di dispersione scolastica nel primo biennio. Al termine delle nuove iniziative educative realizzate, dal confronto con i risultati degli anni precedenti, si è notato un aumento dei voti in matematica e in lingua italiana, una diminuzione delle assenze e dei ritardi all’ingresso e un aumento dei contatti tra genitori e insegnanti. The intervention was aimed to verify whether the integration of school action (being school a formal educ…