Absorption and dispersion studies of thermally evaporated nanocrytallite structure ZnIn2Se4thin films

2009 ◽  
Vol 45 (3) ◽  
pp. 30601 ◽  
Author(s):  
H. M. Zeyada ◽  
M. S. Aziz ◽  
A. S. Behairy
Author(s):  
Muhammad Ali Abbas ◽  
Luuk van Dijk ◽  
Khalil Eslami Jahromi ◽  
Mohammadreza Nematollahi ◽  
Frans J. M. Harren ◽  
...  

Geophysics ◽  
2016 ◽  
Vol 81 (5) ◽  
pp. S317-S331 ◽  
Author(s):  
Jianfeng Zhang ◽  
Zhengwei Li ◽  
Linong Liu ◽  
Jin Wang ◽  
Jincheng Xu

We have improved the so-called deabsorption prestack time migration (PSTM) by introducing a dip-angle domain stationary-phase implementation. Deabsorption PSTM compensates absorption and dispersion via an actual wave propagation path using effective [Formula: see text] parameters that are obtained during migration. However, noises induced by the compensation degrade the resolution gained and deabsorption PSTM requires more computational effort than conventional PSTM. Our stationary-phase implementation improves deabsorption PSTM through the determination of an optimal migration aperture based on an estimate of the Fresnel zone. This significantly attenuates the noises and reduces the computational cost of 3D deabsorption PSTM. We have estimated the 2D Fresnel zone in terms of two dip angles through building a pair of 1D migrated dip-angle gathers using PSTM. Our stationary-phase QPSTM (deabsorption PSTM) was implemented as a two-stage process. First, we used conventional PSTM to obtain the Fresnel zones. Then, we performed deabsorption PSTM with the Fresnel-zone-based optimized migration aperture. We applied stationary-phase QPSTM to a 3D field data. Comparison with synthetic seismogram generated from well log data validates the resolution enhancements.


2010 ◽  
Vol 19 (03) ◽  
pp. 427-436
Author(s):  
A. MENDOZA-GARCÍA ◽  
A. ROMERO-DEPABLOS ◽  
M. A. ORTEGA ◽  
J. L. PAZ ◽  
L. ECHEVARRÍA

We have developed an analytical method to describe the optical properties of nanoparticles, whose results are in agreement with the observed experimental behavior according to the size of the nanoparticle under analysis. Our considerations to describe plasmonic absorption and dispersion are based on the combination of the two-level molecular system and the two-dimensional quantum box models. Employing the optical stochastic Bloch equations, we have determined the system's coherence, from which we have calculated expressions for the absorption coefficient and refractive index. The innovation of this methodology is that it allows us to take into account the solvent environment, which induce quantum effects not considered by classical treatments.


1946 ◽  
Vol 19 (4) ◽  
pp. 1085-1087
Author(s):  
Pierre Girard ◽  
Paul Abadie

Abstract The spectra which were studied lie within the region of hertzian frequencies, and can be represented either by dispersion curves showing the dielectric constant of the substance as a function of the frequency (or wave length λ), or by absorption curves showing the loss angle as a function of this frequency. These two types of curves represent the same phenomenon, i.e., orientation of the dipolar molecules in the alternating electric field, in accordance with the theory of Debye. The spectra and their interpretation depend chiefly on whether the molecules are crystalloid with relatively small and similar dimensions, or are colloidal, with large and unequal dimensions. In the first case, the spectra gives evidence chiefly on the form of the molecules and their structural features. Dilution in a nonpolar solvent shows for certain dipolar compounds, e.g., alcohol, considerable deformations, which differ according to the solvent. In the case of colloids, e.g., rubber, which has a permanent moment, the spectra and the meaning of these spectra are far different. In this case the spectra indicate that the absorption and dispersion values in the hertzian region are closely related to the micellar constitution, i.e., to the different types of micelles, to their size, and to the proportion of each type.


1989 ◽  
Vol 38 (10) ◽  
pp. 1601
Author(s):  
ZHANG WEI-PING ◽  
TAN WEI-HAN

2021 ◽  
pp. 4-11
Author(s):  
V. N. Danilov

On the basis of modelling an acoustic path of the angle beam probe with a reflector as a side drilled hole influence of two factors resulting to quasiband of acoustic axis of the angle beam probe is shown, first of which is connected to change of amplitude echo signal owing to attenuation of a shear wave in the environment due to absorption and dispersion, and the second factor – with change of amplitude owing to a divergence of wave fronts radiated and received elastic waves. Influence of the first factor is increased with growth of attenuation and depth of reflector, and the second – on increase of distance up to a reflector practically does not depend. Quantitative estimations have revealed a ratio of influence of both factors on size of a angle quasiband of acoustic axis on value of factor of attenuation of shear waves. Reduction of an angle quasidand with increase of radius piezoplate of the angle beam probe is shown at constant operation frequency, that is at narrowing the directivity characteristic of the probe.


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