Search results for "T wave"
showing 10 items of 94 documents
Extraction and fusion of spectral parameters for face recognition
2011
This is the copy of journal's version originally published in Proc. SPIE 7877: http://spie.org/x10.xml?WT.svl=tn7. Reprinted with permission of SPIE. Many methods have been developed in image processing for face recognition, especially in recent years with the increase of biometric technologies. However, most of these techniques are used on grayscale images acquired in the visible range of the electromagnetic spectrum. The aims of our study are to improve existing tools and to develop new methods for face recognition. The techniques used take advantage of the different spectral ranges, the visible, optical infrared and thermal infrared, by either combining them or analyzing them separately …
Design of compensated multiport waveguide junctions considering mechanization effects
2015
Abstract A new tool for the rigorous and efficient design of compensated multiport waveguide junctions, considering the mechanization effects due to low-cost manufacture techniques, is presented. Several new designs for a great variety of key components, present in modern microwave and millimetre-wave equipment, are proposed taking into account the introduction of rounded corners in the rectangular waveguide access ports. The new implemented tool permits to control and compensate for the potential degradation of the wide-band performance of such components prior to their fabrication, thus achieving an optimal design. All the presented results have been successfully validated by comparing th…
Gamma-ray burst afterglow light curves from realistic density profiles
2011
The afterglow emission that follows gamma-ray bursts (GRBs) contains valuable information about the circumburst medium and, therefore, about the GRB progenitor. Theoretical studies of GRB blast waves, however, are often limited to simple density profiles for the external medium (mostly constant density and power-law R^{-k} ones). We argue that a large fraction of long-duration GRBs should take place in massive stellar clusters where the circumburst medium is much more complicated. As a case study, we simulate the propagation of a GRB blast wave in a medium shaped by the collision of the winds of O and Wolf-Rayet stars, the typical distance of which is d /sim 0.1 - 1 pc. Assuming a spherical…
Wave propagation in optical systems
1974
The intensity distribution in the image space of an optical system, due to an arbitrary object, is calculated by solving the problem of the propagation of a monochromatic light wave through the system. The system is assumed to be cylindrically symmetric with an arbitrary number of spherical surfaces. Analytic techniques based on the principle of stationary phase are used, and several advantages over ray-tracing techniques are obtained.
Initial state dependence of a quantum-resonance ratchet
2016
We demonstrate quantum resonance ratchets created with Bose-Einstein condensates exposed to pulses of an off-resonant standing light wave. We show how some of the basic properties of the ratchets are controllable through the creation of different initial states of the system. In particular, our results prove that through an appropriate choice of initial state it is possible to reduce the extent to which the ratchet state changes with respect to time. We develop a simple theory to explain our results and indicate how ratchets might be used as part of a matter wave interferometer or quantum-random walk experiment.
Rigidity and Dynamics of Random Spring Networks
1996
The static and dynamic elastic properties of two-dimensional random networks composed of Hookean springs are analyzed. These networks are proved to be nonrigid with respect to small deformations, and the floppy mode ratio is calculated exactly. The vibrational spectrum is shown to consist only of zero-frequency and localized modes. The exponential decay of the amplitude and velocity of the transient wave front are shown to be exactly described by a quasi-one-dimensional model of noninteracting paths of propagation.
Radiation resonant transmission and reflection by a thin layer of an anisotropic plasma
2005
The possibility of radiation resonant transmission and reflection by a thin layer of a plasma possessing an anisotropic electron velocity distribution strongly elongated in the direction of the incident wave polarization is established.
Thermal solitons along wires with flux-limited lateral exchange
2021
We obtain some exact solutions in the context of solitons, for heat conduction with inertia along a cylinder whose heat exchange with the environment is a non-linear function of the difference of temperatures of the cylinder and the environment, due to a flux-limiter behavior of the exchange. We study the consequences of heat transfer and information transfer along the wire, and we compare the situation with analogous solitons found in nonlinear lateral radiative exchange studied in some previous papers. We also find further exact solutions in terms of Weierstrass elliptic functions for the sake of completeness.
Applications of near-field optics to the characterization of optoelectronics components
1997
In the race towards purely optical communications, the necessity of producing integrated components is linked to the requirement for the precise characteriza-tion of optoelectronic components. Near-field detection techniques meet this requirement, AFM (Atomic Force Microscopy), for instance, can provide the topography of a given sample. In conjunction with these new tools, several different kinds of near-field optical microscopes (NFOM) have appeared. They enable the characteriza-tion of the components with a resolution better than that imposed by the Rayleigh criterion. This is primarily due to the fact that they are sensitive to the evanescent waves. This document presents several areas r…
S-matrix formulation of mesoscopic systems and evanescent modes.
2009
The Landauer-Butikker formalism is an important formalism to study mesoscopic systems. Its validity for linear transport is well established theoretically as well as experimentally. Akkermans et al [Phys. Rev. Lett. {\bf 66}, 76 (1991)] had shown that the formalism can be extended to study thermodynamic properties like persistent currents. It was earlier verified for simple one dimensional systems. We study this formula very carefully and conclude that it requires reinterpretation in quasi one dimension. This is essentially because of the presence of evanescent modes in quasi one dimension.