Combined effect of exciton–exciton and exciton–phonon interaction on crystal's dielectric properties

1982 ◽  
Vol 60 (12) ◽  
pp. 1838-1845 ◽  
Author(s):  
D. Mirjanić ◽  
U. Luburić-Kozmidis ◽  
M. M. Marinković ◽  
B. S. Tošić
Keyword(s):  
Dielectric Properties ◽  
Molecular Crystals ◽  
Wavelength Region ◽  
Combined Effect ◽  
The Other ◽  
Green Functions ◽  
Phonon Interaction ◽  
Double Peak ◽  
Exciton Interaction ◽  
Order Of Magnitude

The two-time temperature Green functions method is used to investigate the combined effect of the exciton–exciton and the exciton–phonon interactions on the dielectric properties of the molecular crystals. It is shown that those effects are of the same order of magnitude. The most interesting result is nevertheless the appearance of a double peak in the region ω < ωexciton whereby the narrow peak is due to the exciton–phonon interaction whereas the other, located in the longer wavelength region, is due to the exciton–exciton interaction. The possible further generalization of the results obtained is also discussed.

Electron and phonon Green functions in a one-dimensional model

1969 ◽  
Vol 47 (22) ◽  
pp. 2475-2486 ◽  
Author(s):  
Dennis Dunn
Keyword(s):  
Dielectric Properties ◽  
Green Functions ◽  
External Fields ◽  
Dimensional Model ◽  
Phonon Interaction ◽  
Fermion Model ◽  
One Dimensional ◽  
Electron Phonon Interaction ◽  
Luttinger Model ◽  
General Response

We consider a one-dimensional fermion model which is similar to the Luttinger model and which also includes an electron-phonon interaction. We show that in this model the electron, phonon, and plasmon Green functions can all be determined exactly.We examine the dielectric properties of the system and also the more general response of the system to arbitrary external fields and we show that the response is strictly linear in these fields.

Comparison of the Potency of 8-L-Arginine, 8-D-Arginine and 8-D-Homoarginine Vasopressin Analogs with Substituted Phenylalanine in Position 2

1994 ◽  
Vol 59 (6) ◽  
pp. 1439-1450 ◽  
Author(s):  
Miroslava Žertová ◽  
Jiřina Slaninová ◽  
Zdenko Procházka
Keyword(s):  
Amino Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Basic Amino Acid ◽  
The Other ◽  
Side Chain ◽  
Inhibitory Potency ◽  
Phase Synthesis ◽  
Other Hand ◽  
Order Of Magnitude

An analysis of the uterotonic potencies of all analogs having substituted L- or D-tyrosine or -phenylalanine in position 2 and L-arginine, D-arginine or D-homoarginine in position 8 was made. The series of analogs already published was completed by the solid phase synthesis of ten new analogs having L- or D-Phe, L- or D-Phe(2-Et), L- or D-Phe(2,4,6-triMe) or D-Tyr(Me) in position 2 and either L- or D-arginine in position 8. All newly synthesized analogs were found to be uterotonic inhibitors. Deamination increases both the agonistic and antagonistic potency. In the case of phenylalanine analogs the change of configuration from L to D in position 2 enhances the uterotonic inhibition for more than 1 order of magnitude. The L to D change in position 8 enhances the inhibitory potency negligibly. Prolongation of the side chain of the D-basic amino acid in position 8 seems to decrease slightly the inhibitory potency if there is L-substituted amino acid in position 2. On the other hand there is a tendency to the increase of the inhibitory potency if there is D-substituted amino acid in position 2.

Epitaxial Growth and Anisotropic Dielectric Properties of La-Doped Bi4Ti3O12 Thin Films

2007 ◽  
Vol 124-126 ◽  
pp. 177-180
Author(s):  
Jang Sik Lee ◽  
Q.X. Jia
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Bottom Electrode ◽  
Dielectric Constants ◽  
The Other ◽  
Field Range ◽  
Anisotropic Dielectric ◽  
Dielectric Nonlinearity ◽  
La Doped

To investigate the anisotropic dielectric properties of layer-structured bismuth-based ferroelectrics along different crystal directions, we fabricate devices along different crystal orientations using highly c-axis oriented Bi3.25La0.75Ti3O12 (BLT) thin films on (001) LaAlO3 (LAO) substrates. Experimental results have shown that the dielectric properties of the BLT films are highly anisotropic along different crystal directions. The dielectric constants (1MHz at 300 K) are 358 and 160 along [100] and [110], respectively. Dielectric nonlinearity is also detected along these crystal directions. On the other hand, a much smaller dielectric constant and no detectable dielectric nonlinearity in a field range of 0-200 kV/cm are observed for films along [001] when c-axis oriented SRO is used as the bottom electrode.

scholarly journals On the 2PN Periastron Precession of the Double Pulsar PSR J0737–3039A/B

Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 443
Author(s):  
Lorenzo Iorio
Keyword(s):  
General Relativity ◽  
Present Author ◽  
Moment Of Inertia ◽  
The Other ◽  
Orbital Elements ◽  
Binary Pulsars ◽  
Orbital Phase ◽  
Order Of Magnitude ◽  
General Relativistic ◽  
The Moment

One of the post-Keplerian (PK) parameters determined in timing analyses of several binary pulsars is the fractional periastron advance per orbit kPK. Along with other PK parameters, it is used in testing general relativity once it is translated into the periastron precession ω˙PK. It was recently remarked that the periastron ω of PSR J0737–3039A/B may be used to measure/constrain the moment of inertia of A through the extraction of the general relativistic Lense–Thirring precession ω˙LT,A≃−0.00060∘yr−1 from the experimentally determined periastron rate ω˙obs provided that the other post-Newtonian (PN) contributions to ω˙exp can be accurately modeled. Among them, the 2PN seems to be of the same order of magnitude of ω˙LT,A. An analytical expression of the total 2PN periastron precession ω˙2PN in terms of the osculating Keplerian orbital elements, valid not only for binary pulsars, is provided, thereby elucidating the subtleties implied in correctly calculating it from k1PN+k2PN and correcting some past errors by the present author. The formula for ω˙2PN is demonstrated to be equivalent to that obtainable from k1PN+k2PN by Damour and Schäfer expressed in the Damour–Deruelle (DD) parameterization. ω˙2PN actually depends on the initial orbital phase, hidden in the DD picture, so that −0.00080∘yr−1≤ω˙2PN≤−0.00045∘yr−1. A recently released prediction of ω˙2PN for PSR J0737–3039A/B is discussed.

scholarly journals Многократное изменение электрон-фононного взаимодействия в квантовых ямах с диэлектрически различными барьерами

2022 ◽  
Vol 56 (1) ◽  
pp. 101
Author(s):  
А.Ю. Маслов ◽  
О.В. Прошина
Keyword(s):  
Quantum Wells ◽  
Charged Particles ◽  
Strong Interactions ◽  
Asymmetric Structure ◽  
Optical Phonons ◽  
Phonon Modes ◽  
Phonon Interaction ◽  
Barrier Materials ◽  
Electron Phonon Interaction ◽  
Order Of Magnitude

Abstract The specific features of the interaction of charged particles with polar optical phonons have been studied theoretically for quantum wells with the barriers that are asymmetric in their dielectric properties. It is shown that the interaction with interface phonon modes makes the greatest contribution in narrow quantum wells. The parameters of the electron-phonon interaction were found for the cases of different values of the phonon frequencies in the barrier materials. It turned out that a significant (by almost an order of magnitude) change in the parameters of the electron-phonon interaction can occur in such structures. This makes it possible, in principle, to trace the transition from weak to strong interactions in quantum wells of the same type but with different compositions of barrier materials. The conditions are found under which an enhancement of the electron-phonon interaction is possible in an asymmetric structure in comparison with a symmetric one with the barriers of the same composition.

scholarly journals A.C conductivity and dielectric properties of (PVA/ PEO) blends doped with MWCNTs

2019 ◽  
Vol 14 (30) ◽  
pp. 64-72
Author(s):  
Ahmad A. Hasan
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Properties ◽  
The Other ◽  
Poly Vinyl Alcohol ◽  
Conductivity Measurements ◽  
Frequency Range ◽  
Maximum Value ◽  
Multi Walled Carbon Nanotube ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

A.C electrical conductivity and dielectric properties for poly(vinyl alcohol) (PVA) /poly (ethylene oxide) (PEO) blends undopedand doped with multi-walled carbon nanotube (MWCNTs) withdifferent concentrations (1, and 3 wt %) in the frequency range(25x103 - 5x106 Hz) were investigated. Samples of (PVA/PEO)blends undoped and doped with MWCNTs were prepared usingcasting technique. The electrical conductivity measurements showedthat σA.C is frequency dependent and obey the relation σA.C =Aωs forundoped and doped blends with 1% MWCNTs, while it is frequencyindependent with increases of MWCNTs content to 3%. Theexponent s showed proceeding increase with the increase of PEOratio (≥50%) for undoped blends samples, while s value for dopedblends exhibits to change in different manner, i.e. s increases andreach maximum value at 50/50 PVA/PEO, then decreases forresidual doped blends samples with 1% MWCNTs on the other handthe exponent s decrease and reach minimum value at 50/50PVA/PEO for samples doped with 3% MWCNTs, then return toincrease. The results explained in different terms.

Effect of bromine deficiency on the lattice dynamics and dielectric properties of alpha-phase diisopropylammonium bromide molecular crystals

2018 ◽  
Vol 113 ◽  
pp. 82-85 ◽  
Author(s):  
Ahmad Alsaad ◽  
Chris M. Marin ◽  
Nabil Alaqtash ◽  
Hsien-Wen Chao ◽  
Tsun-Hsu Chang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Lattice Dynamics ◽  
Molecular Crystals ◽  
Alpha Phase

Evaluation of the Service Performance of Ships

2005 ◽  
Vol 42 (04) ◽  
pp. 177-183
Author(s):  
Poul Andersen ◽  
Anne-Sophie Borrod ◽  
Hervé Blanchot
Keyword(s):  
Input Data ◽  
High Efficiency ◽  
Service Performance ◽  
The Other ◽  
Simple Method ◽  
Propulsive Efficiency ◽  
Order Of Magnitude ◽  
Time Periods

A simple method has been established for the evaluation of the service performance of ships. Input data are easily collected daily on board and transformed to a well-defined condition that makes possible the comparison between ships, for instance, sister ships, and between different time periods of voyages for the same ship. The procedure has been applied to two ships that are identical, with the only exception that one has a conventional propeller, whereas the other one is fitted with a high-efficiency propeller of the KAPPEL type. The results are obtained from a period of 2 years steaming for both vessels. They clearly confirm the increase of propulsive efficiency obtained with the KAPPEL propeller in the order of magnitude of 4%.

scholarly journals The Near-Synchronous Polar Candidate V4633 Sgr (Nova Sagittarii 1998)

2004 ◽  
Vol 190 ◽  
pp. 176-177
Author(s):  
Y. Lipkin ◽  
E. M. Leibowitz
Keyword(s):  
Angular Momentum ◽  
Momentum Transfer ◽  
White Dwarf ◽  
Moment Of Inertia ◽  
The Other ◽  
Angular Momentum Transfer ◽  
Classical Nova ◽  
Order Of Magnitude ◽  
Photometric Monitoring ◽  
The Moment

AbstractThe classical nova V4633 Sgr (1998) exhibits two photometric periodicities. The shorter period (P1=3.01 hr) is stable, while the other one, longer by ~2.5%, has decreased monotonically since shortly after the nova eruption, with Ṗ2 ≈ –10−6 (Lipkin et al. 2001).Here we report on results of photometric monitoring of the star in 2001 and 2002. During our observations, the longer period decreased more, and in 2002 it was only 1.8% longer than P1 The decrease rate (Ṗ2) in 2001-2002 was an order of magnitude smaller than in 1998-2000.These new results support the Near-Synchronous Polar classification which was suggested for V4633 Sgr (Lipkin et al. 2001). In this model, the longer period of V4633 Sgr is the spin of the white dwarf, and its variation since 1998 reflects changes in the moment of inertia of the white dwarf, and angular momentum transfer in the system following the nova eruption.

scholarly journals Topological susceptibility with a single light quark flavour

2018 ◽  
Vol 175 ◽  
pp. 14017 ◽  
Author(s):  
Julien Frison ◽  
Ryuichiro Kitano ◽  
Norikazu Yamada
Keyword(s):  
Quark Mass ◽  
Continuum Limit ◽  
Light Quark ◽  
The Other ◽  
Theoretical Argument ◽  
Up Quark ◽  
Order Of Magnitude ◽  
Quark Flavour ◽  
Definition Of ◽  
The Continuum

One of the historical suggestions to tackle the strong CP problem is to take the up quark mass to zero while keeping md finite. The θ angle is then supposed to become irrelevant, i.e. the topological susceptibility vanishes. However, the definition of the quark mass is scheme-dependent and identifying the mu = 0 point is not trivial, in particular with Wilson-like fermions. More specifically, up to our knowledge there is no theoretical argument guaranteeing that the topological susceptibility exactly vanishes when the PCAC mass does. We will present our recent progresses on the empirical check of this property using Nf = 1 + 2 flavours of clover fermions, where the lightest fermion is tuned very close to [see formula in PDF] and the mass of the other two is kept of the order of magnitude of the physical ms. This choice is indeed expected to amplify any unknown non-perturbative effect caused by mu ≠ md. The simulation is repeated for several βs and those results, although preliminary, give a hint about what happens in the continuum limit.

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