Search results for "Indrica"

<title>Eye model with controllable lens scattering</title>

2001

A model of human eye for experiments in vision research has been developed using PLZT ceramics. This ``artificial eye{''} allows to simulate light scattering caused by cataract in the eye lens. Light scattering of a composite eye lens of the model depends on the electric field applied to a transparent electrooptic PLZT ceramics plate that is attached directly to the lens. The image degradation in such a model eye at various degrees of scattering is studied observing and recording the contrast of images on the ``retinal plane{''} created by standard test objects with different spatial frequency or by a He-Ne laser source passing a diffractive transparent placed before the eye.

First principles modeling of 3d-metal doped three-layer fluorite-structured TiO2 (4,4) nanotube to be used for photocatalytic hydrogen production

2017

This study has been supported by the EC ERA.Net RUS Plus project No. 237 WATERSPLIT, Russian Basic Research Foundation No. 16-53-76019, and additionally by the IMIS2 Program (Latvia). The authors are also indebted to R. A. Evarestov and O. Lisovski for stimulating discussions as well as to A. Chesnokov for technical assistance.

EP-1166: DVHs evaluation for vmat-imrt planning in cylindrical phantom DELTA4

2013

Analysis of a Parabolic Cross-Diffusion Semiconductor Model with Electron-Hole Scattering

2007

The global-in-time existence of non-negative solutions to a parabolic strongly coupled system with mixed Dirichlet–Neumann boundary conditions is shown. The system describes the time evolution of the electron and hole densities in a semiconductor when electron-hole scattering is taken into account. The parabolic equations are coupled to the Poisson equation for the electrostatic potential. Written in the quasi-Fermi potential variables, the diffusion matrix of the parabolic system contains strong cross-diffusion terms and is only positive semi-definite such that the problem is formally of degenerate type. The existence proof is based on the study of a fully discretized version of the system…

Comparison of different methods for evaluating the transmission function of a two-stage cylindrical mirror analizer in XPS applications

2007

Three different evaluations of the energy dependence of the transmission-detection function of a two-stage cylindrical electron analyzer have been obtained by resorting to three established procedures. Their relative merits have been tested as follows. First they have been used to correct raw XPS spectra of clean Cu, Ag and Au surfaces. Next, the secondary electron background has been subtracted using Tougaard's method. Finally, the primary electron spectra so obtained have been reanalyzed by peak area measurement in the frame of the modern formalism for quantitative XPS analysis. Ideally a constant residual value should thus be obtained. The variability of these residuals with peak energy …

Simulations with Smoothed Particles Confirm Stationary Shocks in Accretion Flows onto Black Holes

1994

We present the results of time dependent numerical simulations of the accretion of gas onto Schartzschild black holes. We find that stable shocks are a common feature for flows of inviscid gas accreting with small angular momentum per unit mass. We used the Smoothed Particles Hydrodynamics tecnique, expressed into cylindrical coordinates to exploit the axial symmetry of the problem. For the case of 1-Dimensional axis-symmetric simulations we find that the shock location is exactly at the position predicted by the stationary analysis developed by Chakrabarti. We solve also the ambiguity related to the two possible shock positions: only the outer shock is stable. The case of 2-Dimensional axi…

Potential and energy of some spheroidal charge distributions with azimuthal symmetry

1989

Abstract The Poisson equation is solved for three types of spheroidal charge distributions with azimuthal symmetry, namely, those depending on one cartesian coordinate, on the radial cylindrical coordinate and on the radial spherical coordinate. The energy of such distributions is found for the case of power functions of these coordinates and it has been normalized, computed and plotted for some low values of the exponent.

X-rays from protostellar jets: emission from continuous flows

2006

Recently X-ray emission from protostellar jets has been detected with both XMM-Newton and Chandra satellites, but the physical mechanism which can give rise to this emission is still unclear. We performed an extensive exploration of a wide space of the main parameters influencing the jet/ambient interaction. Aims include: 1) to constrain the jet/ambient interaction regimes leading to the X-ray emission observed in Herbig-Haro objects in terms of the emission by a shock forming at the interaction front between a continuous supersonic jet and the surrounding medium; 2) to derive detailed predictions to be compared with optical and X-ray observations of protostellar jets; 3) to get insight int…

Monte Carlo simulations of the 2d-Ising model in the geometry of a long stripe

2011

Abstract The two-dimensional Ising model in the geometry of a long stripe can be regarded as a model system for the study of nanopores. As a quasi-one-dimensional system, it also exhibits a rather interesting “phase behavior”: At low temperatures the stripe is either filled with “liquid” or “gas” and “densities” are similar to those in the bulk. When we approach a “pseudo-critical point” (below the critical point of the bulk) at which the correlation length becomes comparable to the length of the stripe, several interfaces emerge and the systems contains multiple “liquid” and “gas” domains. The transition depends on the size of the stripe and occurs at lower temperatures for larger stripes.…

Comparaison de la mesure des déformations de fantômes de l’aorte à partir d’image obtenues par IRM et stéréovision

2015

International audience; The study of the wall strain distribution could be helpful to improve the decision criterion for surgery of aortic aneurysm. Recently, numerical simulations can complete the data obtained from imaging measurement in order to develop reliable models. However, the used medical imaging tools are not experimentally validated, in metrological point of view. The aim of this study focused on accuracy and reliability of measurement obtained from kinetic MR sequences. The measures of deformations from MRI were compare to those obtained from stereovision system. Cylindrical phantom of silicone material similar to arterial behavior simulated a symmetric aneurysm was designed. A…