Search results for "Dispersion"

Practical design rules for single-channel ultra high-speed dense dispersion management telecommunication systems

2009

International audience; In this work, we establish some efficient and practical design rules for the implementation of single-channel ultra-high speed (>160-Gbit/s) telecommunication systems based on dense dispersion management. Moreover, we analyze some of actual implementation issues such as slope compensation scenario, junction losses, polarization mode dispersion and chromatic dispersion fluctuations.

Sul perché le descrizioni dipendono dalle intenzioni progettuali. Possibili letture dei territori della dispersione

2008

Secchi (1996) afferma che descrivere e interpretare sono operazioni altamente selettive che concorrono alla costruzione del progetto. Altresì Vettoretto (!994) ribadisce la non neutralità di tali operazioni che rivelano, invece, le "intenzioni" progettuali. Il saggio raccoglie alcune descrizioni/interpretazioni elaborate sulla dispersione insediativa che mettono in luce i differenti approcci progettuali degli autori.

Vanadium Carbide Dissolution during Austenitisation of a Model Microalloyed FeCV Steel

2005

High performance commercial micro alloyed steels contain elements such as vanadium, which leads to a fine dispersion of vanadium carbide precipitates. The precipitation state, in terms of volume fraction and size distribution, plays a significant role in final mechanical properties of the material. Different austenitisation heat treatments were performed on a model ternary alloy FeCV. Precipitation states were characterised combining different experimental techniques. TEM was used to identify the chemical composition of observed precipitates. ICP mass spectroscopy was performed to measure the volume fraction of precipitates. The size distribution was studied by SEM. Results are characterist…

Technology Diffusion, Worker Mobility and the Returns to Skill

2015

In this paper I illustrate how the diffusion across firms of a skill-neutral technology leads to a skill-biased impact on the economy. The model identifies (i) differences in inter-firm mobility between skill groups, (ii) productivity dispersion across firms within industries, and (iii) differences in wages between small and large firms as key determinants of the skill premium. Calibrated to match differences in inter-firm mobility between skill groups and rising productivity dispersion across firms, the model ascribes one-third of the sharp increase in the skill premium in U.S. manufacturing from 1977 to 1997 to skill-neutral technical progress and the technology diffusion process itself. …

Interpreting and modelling field data for wastewater dispersion into sea through dimensional analysis

2008

Assessment of protection treatments for carbonatic stone using nanocomposite coatings

2020

In this paper the effect of the application of four kinds of polymer dispersions containing nanoparticles, used as protectives, on two type of carbonatic lithotypes, White Noto and Comiso stone, is reported. The study was conducted by analysing the contribution of each component of the system. After the structural characterization of the coating itself, the performance of those colloidal systems has been studied upon application on the calcarenites, preferring non-invasive techniques and microdestructive techniques. Effect of the nanoparticles presence on hydrorepellency and roughness of the stone surface and on chromatic changes has also been considered. The tests conducted have proven tha…

Fast relaxation phenomena and slow mode in extended thermodynamics of superfluids

2003

A macroscopic monofluid model of liquid helium II which is based on extended thermodynamics was formulated in previous works, both in the presence and in the absence of dissipative phenomena. In all these studies, the time evolution of the nonequilibrium stress tensor was neglected, putting the relaxation times @t"0 and @t"2 of the nonequilibrium pressure and of the stress deviator equal to zero. In this work, the time evolution of these fields is not neglected and the complete model with 14 fields is studied, in the linear approximation. The propagation of waves is studied and a dispersion relation of degree 14 is obtained. The solutions of this equation are carried out, perturbing the sol…

Resonant Beam Steering and Carpet Cloaking Using an Acoustic Transformational Metascreen

2018

International audience; We invoke the Huygens principle to derive dispersion characteristics of acoustic transformational meta-surfaces that can deflect parallel wavefronts in a desired direction. We also propose a dual-Lorentz resonator whose aperture fields can be tuned by geometrical changes to implement a particular phase with unity reflection coefficient. The proposed metascreen is designed by our arranging slightly detuned Lorentz cavities that generate the necessary interference to compensate for the incident wavefronts. Since a complete 0-2 pi range of the reflection phase is achieved, the metascreen can steer a beam across the full horizon. Moreover, since the proposed dual resonat…

Modeling propagation for high-power cylindrical microwave applicators

2001

In this letter, the dispersion characteristics and energy configurations of a cylindrical partially filled waveguide or lossy multilayered rod shielded by a metallic enclosure are presented for several modes. These parameters are obtained by a numerical simulation based on the residues theory. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 192–195, 2001.

Broadband telecom to mid-infrared supercontinuum generation in a dispersion-engineered silicon germanium waveguide.

2015

We demonstrate broadband supercontinuum generation (SCG) in a dispersion-engineered silicon-germanium waveguide. The 3 cm long waveguide is pumped by femtosecond pulses at 2.4 μm, and the generated supercontinuum extends from 1.45 to 2.79 μm (at the −30  dB point). The broadening is mainly driven by the generation of a dispersive wave in the 1.5–1.8 μm region and soliton fission. The SCG was modeled numerically, and excellent agreement with the experimental results was obtained.