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Journal articles on the topic 'Zener Theory'

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Published: 6 September 2023

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1

Tsai, Ping-Kun, Cheng-Han Li, Chia-Chun Lai, Ko-Jung Huang, and Ching-Wei Cheng. "Approximation Solution for the Zener Impact Theory." Mathematics 9, no. 18 (September 10, 2021): 2222. http://dx.doi.org/10.3390/math9182222.

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Collisions can be classified as completely elastic or inelastic. Collision mechanics theory has gradually developed from elastic to inelastic collision theories. Based on the Hertz elastic collision contact theory and Zener inelastic collision theory model, we derive and explain the Hertz and Zener collision theory model equations in detail in this study and establish the Zener inelastic collision theory, which is a simple and fast calculation of the approximate solution to the nonlinear differential equations of motion. We propose an approximate formula to obtain the Zener nonlinear differential equation of motion in a simple manner. The approximate solution determines the relevant values of the collision force, material displacement, velocity, and contact time.
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2

Abbruzzese, Giuseppe Carlo, and Massimiliano Buccioni. "Theory of Grain Growth in the Presence of Atoms Drag Effects." Materials Science Forum 558-559 (October 2007): 1005–12. http://dx.doi.org/10.4028/www.scientific.net/msf.558-559.1005.

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The statistical model of grain growth is able to predict the effect of Zener drag on the grain size distribution evolution and on grain growth kinetics [1, 2]. This paper, in the same framework, will treat the case of atoms drag on grain boundary movement. The mechanism by which atoms drag operates is significantly different by that of Zener. The corresponding peculiar features will result in a specific grain size distribution evolution with considerable change of grain growth kinetics and distribution shape from that of normal grain growth case as a function of the intensity of the pinning conditions.
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3

Amos, A. T., S. G. Davison, and K. W. Sulston. "Rosen-Zener approximation in surface-ion scattering theory." Physics Letters A 118, no. 9 (November 1986): 471–74. http://dx.doi.org/10.1016/0375-9601(86)90754-1.

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4

Carlo, A. Di, and P. Vogl. "Theory of Zener tunnelling and Stark ladders in semiconductors." Semiconductor Science and Technology 9, no. 5S (May 1, 1994): 497–99. http://dx.doi.org/10.1088/0268-1242/9/5s/026.

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5

Park, K. W., J. Kim, J. Seo, S. Moon, K. Jeong, and K. An. "Entropic comparison of Landau–Zener and Demkov interactions in the phase space of a quadrupole billiard." Chaos: An Interdisciplinary Journal of Nonlinear Science 32, no. 10 (October 2022): 103101. http://dx.doi.org/10.1063/5.0101495.

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We investigate two types of avoided crossings in a chaotic billiard within the framework of information theory. The Shannon entropy in the phase space for the Landau–Zener interaction increases as the center of the avoided crossing is approached, whereas for the Demkov interaction, the Shannon entropy decreases as the center of avoided crossing is passed by with an increase in the deformation parameter. This feature can provide a new indicator for scar formation. In addition, it is found that the Fisher information of the Landau–Zener interaction is significantly larger than that of the Demkov interaction.
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6

Liu, Xu, and Stewart Greenhalgh. "Fitting viscoelastic mechanical models to seismic attenuation and velocity dispersion observations and applications to full waveform modelling." Geophysical Journal International 219, no. 3 (August 30, 2019): 1741–56. http://dx.doi.org/10.1093/gji/ggz395.

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SUMMARY The Cole–Cole mechanical model can match a simple seismic attenuation curve over a broad frequency range, but it is not a suitable model for replicating complicated seismic attenuation dispersion curves which exhibit multiple peaks or display pronounced asymmetry. In this case, we use the General Fractional Zener (GFZ) Model, which comprises multiple Cole–Cole elements, to approximate the attenuation observations. The observations here represent the arbitrary (frequency-dependent) dispersion behaviour from actual measurements (phase velocities and/or dissipation factors) or from some physical dissipation mechanism(s) such as local induced fluid flow in effective Biot theory. The key parameters of these viscoelastic models, which include the stress and strain relaxation times and the fractional derivative orders, are determined with a simulated annealing method. Instead of searching for the relaxation times directly, we search for the Zener peak attenuation points and corresponding frequencies, each of which corresponds to a pair of relaxation times. We show that just two fractional Zener elements can sometimes provide a satisfactory approximation to the observations over the entire frequency range. A simple deterministic method is developed to extract the parameters of the single element Zener model using phase velocity observations. As a special case of the GFZ model, we found and proved the constancy of the width of the attenuation curves at the half maximum amplitude point (FWHM) for all Zener models which is critical to the design of reasonable observation frequencies. We stress and demonstrate that ignoring the frequency-dependence of Q may result in significant discrepancies of calculated waveforms with observed or predicted values.
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7

Di Carlo, Aldo, P. Vogl, and W. Pötz. "Theory of Zener tunneling and Wannier-Stark states in semiconductors." Physical Review B 50, no. 12 (September 15, 1994): 8358–77. http://dx.doi.org/10.1103/physrevb.50.8358.

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8

Zhang, Guang-ming, Hong Chen, and Xiang Wu. "A Perturbation Theory of Zener Transitions in Dissipative Driven Systems." Communications in Theoretical Physics 14, no. 3 (October 1990): 267–74. http://dx.doi.org/10.1088/0253-6102/14/3/267.

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9

San Martín, David, Francisca García Caballero, Carlos Capdevila, and Carlos García de Andrés. "Discussion on the Rate Controlling Process of Coarsening of Niobium Carbonitrides in a Niobium Microalloyed Steel." Materials Science Forum 500-501 (November 2005): 703–10. http://dx.doi.org/10.4028/www.scientific.net/msf.500-501.703.

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Austenite grain growth in microalloyed steels is governed by the coarsening of fine precipitates present at grain boundaries below the grain coarsening temperature. Zener model is widely used in metals to describe the pinning effect of second phase particles precipitated in the matrix. In this work it has been discussed whether grain boundary or volume diffusion is the rate controlling process for the coarsening of the niobium carbonitrides. Calculations on austenite grain growth kinetics, obtained coupling Zener theory and both rate controlling processes of precipitate coarsening, have been compared against experimental austenite grain size results under nonisothermal heating conditions. In this sense, it has been concluded that the coarsening of niobium carbonitrides is mainly controlled by volume diffusion of Nb in austenite.
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10

Zhu, Chaoyuan, and Hiroki Nakamura. "Semiclassical theory of multi-channel curve crossing problems: Landau-Zener case." Journal of Chemical Physics 106, no. 7 (February 15, 1997): 2599–611. http://dx.doi.org/10.1063/1.473364.

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11

Yurovsky, V. A., and A. Ben-Reuven. "Incomplete optical shielding in cold atom traps: three-dimensional Landau-Zener theory." Physical Review A 55, no. 5 (May 1, 1997): 3772–79. http://dx.doi.org/10.1103/physreva.55.3772.

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12

Pacheco-Sánchez, J. H., S. Castillo, H. Luna-García, and O. Novaro. "Landau–Zener theory for avoided crossings applied to the gallium–silane reactions." International Journal of Quantum Chemistry 107, no. 15 (2007): 3053–60. http://dx.doi.org/10.1002/qua.21487.

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13

ZHEN, YIN. "DYNAMIC THEORY OF ELECTRON TRANSFER PROCESS." Modern Physics Letters B 02, no. 05 (June 1988): 743–52. http://dx.doi.org/10.1142/s0217984988000448.

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Based on time-dependent Hartree-Fork approximation, we have developed a new technique for dealing with non-adiabatic electron transfer process and also obtained the formula for finding consistently the effective adiabatic parameter and the transition probability. Comparing to Landau-Zener theory our results indicate that the transition probability is greatly influenced by the coupling between the electron and the heat-bath. As the initial state of the electron is in the ground state, interaction between the electron and the heat-bath reduces the transition probability between the electron states. This can be explained that the transition probability from covalent to ionic state in a solute reaction system goes down due to the influence of the solvent. As the initial state of the electron is in the excited state, the coupling to the heat-bath acts to enhance the transition probability between the electron states. This can elucidate that desorption probability decreases in the process of the electron stimulated desorption in virtue of the heat-bath.
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14

Filippov, Sergey N. "Quantum dynamics intervened by repeated nonselective measurements." International Journal of Quantum Information 15, no. 08 (December 2017): 1740027. http://dx.doi.org/10.1142/s0219749917400275.

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We derive the theory of open quantum system dynamics intervened by a series of nonselective measurements. We analyze the cases of time-independent and time-dependent Hamiltonian dynamics between the measurements and find the approximate master equation in the stroboscopic limit. We also consider a situation, in which the measurement basis changes in time, and illustrate it by nonselective measurements in the basis of diabatic states of the Landau–Zener model.
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15

Marino, J., Y. E. Shchadilova, M. Schleier-Smith, and E. A. Demler. "Spectrum, Landau–Zener theory and driven-dissipative dynamics of a staircase of photons." New Journal of Physics 21, no. 1 (January 9, 2019): 013009. http://dx.doi.org/10.1088/1367-2630/aaf825.

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16

Kleinert, P. "Theory of Zener-phonon resonances in the transport of two-band semiconductor superlattices." Journal of Physics: Condensed Matter 12, no. 39 (September 14, 2000): 8467–73. http://dx.doi.org/10.1088/0953-8984/12/39/309.

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17

Kleinert, P., and V. V. Bryksin. "Theory of Zener-photon resonances in the transport of two-band semiconductor superlattices." Journal of Physics: Condensed Matter 13, no. 13 (March 15, 2001): 3157–67. http://dx.doi.org/10.1088/0953-8984/13/13/324.

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18

Freed, A. D., and K. P. Walker. "Steady-State and Transient Zener Parameters in Viscoplasticity: Drag Strength Versus Yield Strength." Applied Mechanics Reviews 43, no. 5S (May 1, 1990): S328—S337. http://dx.doi.org/10.1115/1.3120836.

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A hypothesis is put forth which enables the viscoplastician to formulate a theory of viscoplasticity that reduces, in closed form, to the classical theory of creep. This hypothesis is applied to a variety of drag and yield strength models. Because of two theoretical restrictions that are a consequence of this hypothesis, three different yield strength models and one drag strength model are shown to be theoretically admissible. One of these yield strength models is selected as being the most appropriate representation for isotropic hardening.
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19

IONESCU, MARIUS, LIGIA MUNTEANU, VETURIA CHIROIU, VALERICA MOSNEGUTU, DAN DUMITRIU, and IULIAN GIRIP. "Ricci soliton equation with application to a coupled pendula." Romanian Journal of Technical Sciences - Applied Mechanics 68, no. 1 (April 29, 2023): 59–79. http://dx.doi.org/10.59277/rjts-am.2023.1.04.

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The Ricci equation and the soliton solutions are obtained in this paper for two coupled pendula in order to optimise its locomotion and structure. The robot is swinging repeatedly like a rope with successive movement steps along a mobile support. The cnoidal theory and a genetic algorithm are used to solve the problem via the Ricci solitons and the pseudospherical reduction of the rheological Zener equations. The Bäcklund transform is applied to Ricci equation to generate pseudo-spherical surfaces.
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20

Ranjbaran, Arash, Mohammad Reza Khoshravan, and Mahsa Kharazi. "Analysis of Buckling of Sandwich Plates with Viscoelastic Core Using Layerwise Theory." Applied Mechanics and Materials 798 (October 2015): 462–69. http://dx.doi.org/10.4028/www.scientific.net/amm.798.462.

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Sandwich plates are one of the important components in construction of engineering and especially aerospace structures. In this paper, buckling analysis of sandwich plates was investigated experimentally and analytically using layerwise theory. The sandwich plate was rectangular and made of two composite laminates as skins and a viscoelastic core. The formulation was based on the first order shear deformation theory and the Rayleigh-Ritz method was used for approximating and determining the displacement field. The behavior of viscoelastic material modeled using Zener three-element model. The results obtained from layerwise theory compared with experimental results and showed good agreement. This study demonstrated that, layerwise theory could describe buckling behavior of sandwich plates with high accuracy and represents more realistic and acceptable description of behavior of the plates with much less computational cost.
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21

Buccioni, Massimiliano, and Giuseppe Carlo Abbruzzese. "Microstructure Instability during Particle and Solute Inhibited Grain Growth." Materials Science Forum 715-716 (April 2012): 528. http://dx.doi.org/10.4028/www.scientific.net/msf.715-716.528.

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Grain growth processes in real polycrystalline materials are mostly characterized by the presence of restraining forces, originating, among others, from second phase particles dispersion (Zener drag) or solute atoms segregating at the grain boundaries (solute drag). Both the restraining mechanisms were introduced in the framework of the statistical theory of grain growth, showing their peculiar effects on kinetics and on grain size distribution evolution [1,2,. The present work moves from the previous results and gives a further clarification of pseudo-steady state kinetics occurring under particular solute drag inhibition intensity and will discuss it in comparison with grain growth stagnation conditions produced by Zener drag. In case of second phase particle inhibiting grain growth, the normal case in real systems is the time and temperature dependence of the inhibition intensity due to the evolution of precipitates (e.g. Ostwald ripening. Such evolutions of inhibition, which typically drops with increasing temperature, can cause microstructure instabilities like abnormal grain growth or secondary recrystallization. It is thus introduced in the model a time-temperature depending inhibition drop, which influences both kinetics and grain size distribution evolution. Conditions for the onset of particular effects like abnormal grain growth are assessed and discussed.
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22

DIETL, TOMASZ. "DILUTED FERROMAGNETIC SEMICONDUCTORS — ORIGIN OF MAGNETIC ORDERING AND SPIN-TRANSPORT PROPERTIES." International Journal of Modern Physics B 22, no. 01n02 (January 20, 2008): 104–5. http://dx.doi.org/10.1142/s0217979208046116.

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In the first hour of the lecture the present understanding of the origin of exchange interaction and mechanisms leading to ferromagnetic order in diluted magnetic semiconductors will be presented.1 The lecture will start by discussing energy positions of relevant open magnetic shells, including the correlation energy and excitations within the magnetic ions. The origin and magnitude of sp–d exchange interactions will then be described. This will be followed by presenting the physics of indirect exchange interactions between localized spins contrasting magnetic characteristics in the absence and in the presence of free carriers. The Zener and RKKY models of ferromagnetism will be introduced and the role of confinement, dimensionality, and spin-orbit interaction in determining properties of the ferromagnetic phase will be outlined. The second lecture will be devoted to theory of spin transport in layered structures of diluted ferromagnetic semiconductors, emphasizing the issues important for perspective spintronics devices. A recently developed theory,2 which combines a multi-orbital empirical tight-binding approach with a Landauer–Büttiker formalism will be presented. In contrast to the standard kp method, this theory describes properly the interfaces and inversion symmetry breaking as well as the band dispersion in the entire Brillouin zone, so that the essential for the spin-dependent transport Rashba and Dresselhaus terms as well as the tunneling via k points away from the zone center are taken into account. The applicability of this model for the description of tunneling magnetoresistance (TMR), resonant tunneling spectra, spin-current polarization in Esaki-Zener diodes, and domain-wall resistance will be presented. Note from Publisher: This article contains the abstract only.
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23

Freundlich, Jan. "Transient vibrations of a fractional Zener viscoelastic cantilever beam with a tip mass." Meccanica 56, no. 8 (May 3, 2021): 1971–88. http://dx.doi.org/10.1007/s11012-021-01365-9.

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AbstractThe presented work concerns the kinematically excited transient vibrations of a cantilever beam with a mass element fixed to its free end. The Euler–Bernoulli beam theory and the fractional Zener model of the beam material are assumed. A fractional Caputo derivative is used to formulate a viscoelastic material law. A characteristic equation, modal frequencies, eigenfunction and orthogonality conditions are achieved for the beam considered. The equations of motion of the system are solved numerically. A numerical solution of a multi-term fractional differential equation is obtained by means of a conversion to a mixed system of ordinary and fractional differential equations, each of the order of $$0 < \gamma \le 1$$ 0 < γ ≤ 1 . The transient time histories of the beam vibrations during the passage through resonance are calculated. A comparison between the beam responses obtained with a fractional and an integer viscoelastic material model is presented. The calculations performed reveal that use of the fractional damping affects on the time histories of the system. The calculated beam responses show that for some values of the order of the fractional derivative $$\gamma$$ γ , the amplitudes occurring in the area of the second resonance are greater than those obtained in the area of the first resonance, which does not occur in the case of the integer order of the fractional derivative. Moreover, an evaluation is made of the difference between the results obtained for the calculations using the fractional Zener model and the fractional Kelvin model. It is shown that for some physical beam parameters, the calculation results obtained using both models are virtually the same for both models, which means that the the simpler, fractional Kelvin–Voigt material can be used instead of the fractional Zener material model. This simplifies the solution and decreases the time needed to make the numerical calculations.
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24

Jiang, Yanyu, Qianchu Zhang, and Boris Katsnelson. "Mode coupling in a coastal wedge due to quasi-crossing of range-dependent modal eigenvalues." JASA Express Letters 3, no. 1 (January 2023): 016001. http://dx.doi.org/10.1121/10.0016782.

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A specific mechanism of mode coupling in a waveguide propagation is studied when two range-dependent eigenvalues approach each other. This phenomenon is analogous to the so-called quasi-crossing of states in atomic physics (Landau–Zener theory). It is considered for the sound wave propagation in a coastal wedge in the presence of a sound-speed profile. The change in mode composition and the corresponding spatial variability of the sound field are analyzed by using modes coupling equations and the parabolic equation with a field decomposition over adiabatic modes, respectively.
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25

Ait Ichou, M., H. El Amri, and A. Ezziani. "Mathematical modeling of wave propagation in viscoelastic media with the fractional Zener model." Mathematical Modeling and Computing 8, no. 4 (2021): 601–15. http://dx.doi.org/10.23939/mmc2021.04.601.

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The question of interest for the presented study is the mathematical modeling of wave propagation in dissipative media. The generalized fractional Zener model in the case of dimension d (d=1,2,3) is considered. This work is devoted to the mathematical analysis of such model: existence and uniqueness of the strong and weak solution and energy decay result which guarantees the wave dissipation. The existence of the weak solution is shown using a priori estimates for solutions which are also presented.
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26

Zhu, Chaoyuan, and Hiroki Nakamura. "Theory of nonadiabatic transition for general two‐state curve crossing problems. II. Landau–Zener case." Journal of Chemical Physics 102, no. 19 (May 15, 1995): 7448–61. http://dx.doi.org/10.1063/1.469057.

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27

Agbasi, C., F. Mir, and S. Banerjee. "Modified Zener Theory to Accurately Predict Impact Force Histories for Soft Impactors Employing Spiral Sensing." Experimental Mechanics 57, no. 9 (July 26, 2017): 1435–44. http://dx.doi.org/10.1007/s11340-017-0316-9.

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28

Soufen, Carlos Alberto, Marcelo Capella de Campos, Carlos Alberto Fonzar Pintão, and Momotaro Imaizumi. "Study of Elastic Properies of Ti3Al Intermetallic Compound Using the Ab Initio Calculation." Materials Science Forum 805 (September 2014): 690–93. http://dx.doi.org/10.4028/www.scientific.net/msf.805.690.

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The elastic properties of a Ti3Al intermetallic compound were studied using full potential (FP LAPW ) with the APW+lo method. The FP-LAPW is among the most accurate band structure calculations currently available and is based on the density functional theory with general gradient approximation for the exchange and correlation potential. This method provides the structural properties of the ground state as bulk modulus, equilibrium lattice parameter, and equilibrium minimum energy, and the elastic properties as shear modulus, young modulus, Zener coefficient (anisotropy), and Poisson coefficient. The calculated elastic properties are coherent with the elastic properties of the material.
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29

Aryshenskii, Evgenii, Jurgen Hirsch, Alexander Drits, Sergey Konovalov, Vladimir Aryshenskii, and Maksim Tepterev. "Texture Development in Aluminum Alloys with High Magnesium Content." Metals 12, no. 5 (April 24, 2022): 723. http://dx.doi.org/10.3390/met12050723.

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The evolution of texture in the AlMg6Mn0.7 (1565 ch) alloy throughout the entire cycle of its thermomechanical treatment has been studied. Using this alloy as an example, a new way is shown to control the texture development, which is applicable to alloys with high magnesium content. An integrated approach is applied, including optical and electron microscopy, as well as X-ray diffraction analysis, the determination of mechanical properties and texture modeling using algorithms of the crystallographic plasticity theory. All stages of the thermomechanical treatment have been studied, namely the development of the deformation structure out of the as-cast structure in the reversing hot-rolling stand, continuous hot rolling, cold rolling and final recrystallization annealing. The study showed that second phase particles are the main source of recrystallization nuclei at all stages of high temperature thermomechanical treatment. The importance of these particles increases when the Zener-Hollomon parameter increases. To obtain the maximum possible proportion of a random texture, thermomechanical processing must be carried out at high Zener-Hollomon parameters. However, the temperature should not interfere with the complete recrystallization process at the same time. After cold rolling and recrystallization annealing at temperatures equal or greater than 350 °C, a large proportion of random texture is formed, and the properties of the metal are almost isotropic.
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30

Wang, Xu, Liang Chen, and Peter Schiavone. "Uniformity of stresses inside a non-elliptical inhomogeneity interacting with a mode III crack." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 474, no. 2218 (October 2018): 20180304. http://dx.doi.org/10.1098/rspa.2018.0304.

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Using conformal mapping techniques and the theory of Cauchy singular integral equations, we prove that it is possible to maintain a uniform internal stress field inside a non-elliptical elastic inhomogeneity embedded in an infinite matrix subjected to uniform remote stress despite the fact that the inhomogeneity interacts with a finite mode III crack. The crack can be modelled either as a Griffith crack or as a Zener–Stroh crack. Our analysis further indicates that the existence of the crack plays a key role in influencing the shape of the corresponding inhomogeneity but not the internal uniform stress field inside the inhomogeneity. Numerical examples are presented to demonstrate the solution.
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31

Carcione, José M., Hans B. Helle, and Anthony F. Gangi. "Theory of borehole stability when drilling through salt formations." GEOPHYSICS 71, no. 3 (May 2006): F31—F47. http://dx.doi.org/10.1190/1.2195447.

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We present a mathematical analysis of borehole stability when drilling through rock salt. First, we consider an elastic transversely isotropic medium and find the optimal mud weight as a function of the vertical overburden and horizontal tectonic stresses. Then, the Zener and Maxwell mechanical models are used to model the effects of transient and steady-state creep flow, respectively, in isotropic media. Under certain conditions such as the absence of dilatational anelasticity, the Burger model can be used to describe the steady-state flow, including transient creep effects. The type of creep is regulated by critical octahedral-stress values that depend on temperature and pressure. A typical drilling results in conditions of plane strain, whose solution is given by Kirsch’s equations. In this case, the borehole is subject to minimum and maximum horizontal stresses, which differ from the vertical stress. The analysis provides expressions for the shape of the borehole-cross section, the borehole-wall closure time, and the optimal mud weight to avoid wall collapse or expansion. It is shown that an anisotropic state of tectonic stress may require mud pressures exceeding the overburden stress and that the calculation should consider the joint optimization of the shape and area of the borehole cross section.
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32

Muñoz-Andrade, J. D. "Effect of quantum mechanics and relativistic frequency parameter on hot deformation behaviour of CoCrFeMnNiC0.5 high entropy Alloy." Journal of Physics: Conference Series 2307, no. 1 (September 1, 2022): 012050. http://dx.doi.org/10.1088/1742-6596/2307/1/012050.

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Abstract In the present investigation, a comparative study is carried out between the effect of the frequency parameter suggested by Zener-Hollomon (Z) and the effect of quantum mechanics and relativistic frequency parameter formulated by Muñoz-Andrade (M) on hot deformation behavior of CoCrFeMnNiC0.5 high entropy alloy (HEA), in the temperature range between 973 K and 1273 K and in the strain rate range between 0.001 and 1 s -1. The crucial findings denote that at strain of ε=0.8, the frequency parameter M increased when the temperature and the strain rate increased. Moreover, the nature wavelength (λ) associated with the frequency parameter M is reduced as the temperature and the strain rate are increased. This natural wavelength λ of CoCrFeMnNiC0.5 HEA development during the thermomechanical conditions applied in the present study are in the range between 0.346μm and 0.509μm. Such values are in a closed agreement with the width of the microbands (MBs) produced inside of grains. These MBs are considered as the dominant mechanism inside of crystals during the microstructural evolution related with the phenomenology and mechanics of discontinuous dynamic recrystallization in this HEA. These findings associated with the Muñoz-Andrade frequency parameter M, fully coincide with the Big Bang theory. Nevertheless, the findings associated with the Zener-Hollomon parameter Z, do not obey the Big-Bang theory. For example, the frequency parameter Z at the same deformation (ε=0.8) and thermomechanical conditions decreased as the temperature and the strain rate are increased. Additionally, the wavelength λ associated with the frequency parameter Z is in the range between 162μm and 1630μm, where such values does not coincide with the width of the MBs produced inside of grains during hot deformation of this CoCrFeMnNiC0.5 HEA.
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33

Чирков, П. В., A. A. Мирзоев, and Д. А. Мирзаев. "Молекулярно-динамическое моделирование влияния кремния на упорядочение углерода в решетке мартенсита." Письма в журнал технической физики 44, no. 3 (2018): 9. http://dx.doi.org/10.21883/pjtf.2018.03.45573.16980.

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AbstractThe results of computer simulation of the influence of silicon impurities on the degree of tetragonality and on the interaction of carbon atoms in the body-centered cubic (BCC) lattice of iron by the molecular-dynamics method are reported. The influence of silicon on the martensite-lattice parameters has been established, as well as the dependence of the deformation interaction parameter λ_0 determining the critical temperature of the BCC–BCT (body-centered tetragonal) transition on the silicon concentration, is calculated on the basis of the Zener–Khachaturyan theory of ordering. It is found that the λ_0 parameter decreases by 18% from 5.2 to 4.2 eV/atom upon an increase in the silicon content up to 10 at %.
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34

Rathod, Nikita, S. D. Gupta, Sanjeev K. Gupta, and Prafulla K. Jha. "First-Principles Study of Structural, Electronic, Elastic, Phonon, and Thermodynamical Properties of the Niobium Carbide." Solid State Phenomena 171 (May 2011): 67–77. http://dx.doi.org/10.4028/www.scientific.net/ssp.171.67.

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A detailed theoretical study of structural, electronic and vibrational properties of niobium carbide are carried out in rocksalt phase using the density functional theory implemented in ABINIT code. The calculated structural parameters like lattice constant and bulk modulus agree well with the available data. The Zener anisotropy factor (A), Poison's ratio (v), Young’s modulus (Y) and shear modulus (C’) are also presented. The electronic band structure and density of states are presented and discussed in light of bonding nature in NbC. The band structure indicates its metallic nature. The calculated phonon dispersion curves show that the NbC in rocksalt phase has all positive phonons throughout the Brillouin zone. The thermodynamical properties are also presented and discussed.
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35

Belaïd, Marouane, Stéphane Fontaine, Ali El Hafidi, Papa Benoît Piezel, and Papa Birame Gning. "Prediction of Dissipative Properties of Flax Fibers Reinforced Laminates by Vibration Analysis." Applied Mechanics and Materials 822 (January 2016): 411–17. http://dx.doi.org/10.4028/www.scientific.net/amm.822.411.

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This study proposes an experimental-numeric method to identify the viscoelastic properties of flax fibres reinforced composite laminate (flax/epoxide). The used method consists in identifying the evolutions of both loss factor and stiffness when vibrational frequency changes. In this way, several free-free symmetrically guided beams are excited on a dynamic range of 10 to 4000 Hz with sweep sine excitation focused around the 4-first’s modes. Fractional derivative Zener model is used to identify the on-axis ply complex moduli and describe the laminate dissipative linear behavior with the classical laminate theory. Results obtained on a quasi-isotropic laminate show that this model adequately predicts the vibrational behavior of the tested laminates.
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36

IAFRATE, G. J., J. P. REYNOLDS, J. HE, and J. B. KRIEGER. "BLOCH ELECTRON DYNAMICS IN SPATIALLY HOMOGENEOUS ELECTRIC FIELDS." International Journal of High Speed Electronics and Systems 09, no. 01 (March 1998): 223–50. http://dx.doi.org/10.1142/s0129156498000117.

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The theory of Bloch electron dynamics in spatially homogeneous electric fields of arbitrary strength and time dependence is presented. In the formalism, the electric field is described through the use of the vector potential, and the instantaneous eigenstates of the Hamiltonian are used as basis stated to depict the Bloch dynamics and quantum properties. This approach leads to a natural indication of high- and low-filed limits, and allows for the inclusion of general band-structure effects and multiband coupling in the quantum dynamics. A variety of dc electric field effects, such as Bloch oscillations, Zener tunneling, and localization, and ac electric field effects, such as interband absorption, and phonon-assisted transport, will be discussed.
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37

Jensen, Barbara, and Kevin L. Jensen. "The Quantum Mechanical Extension of the Drude Zener Theory and the Optical Constants of an Alpha Semiconductor." Journal of Computational and Theoretical Nanoscience 6, no. 8 (August 1, 2009): 1770–88. http://dx.doi.org/10.1166/jctn.2009.1242.

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38

Cohen, Boiko, Pavel Leiderman, and Dan Huppert. "Unusual Temperature Dependence of Proton Transfer 3. Classical Kramers' Theory versus the Landau−Zener Curve-Crossing Formulation." Journal of Physical Chemistry A 107, no. 9 (March 2003): 1433–40. http://dx.doi.org/10.1021/jp026415j.

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39

Aaronson, H. I., G. R. Purdy, D. V. Malakhov, and W. T. Reynolds. "Tests of the zener theory of the incomplete transformation phenomenon in Fe-C-Mo and related alloys." Scripta Materialia 44, no. 10 (May 2001): 2425–30. http://dx.doi.org/10.1016/s1359-6462(01)00916-2.

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40

Kaur, Milanpreet, Ravinder Singh Sawhney, and Derick Engles. "Electron transport in doped fullerene molecular junctions." International Journal of Computational Materials Science and Engineering 06, no. 02 (June 2017): 1750019. http://dx.doi.org/10.1142/s2047684117500191.

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The effect of doping on the electron transport of molecular junctions is analyzed in this paper. The doped fullerene molecules are stringed to two semi-infinite gold electrodes and analyzed at equilibrium and nonequilibrium conditions of these device configurations. The contemplation is done using nonequilibrium Green’s function (NEGF)-density functional theory (DFT) to evaluate its density of states (DOS), transmission coefficient, molecular orbitals, electron density, charge transfer, current, and conductance. We conclude from the elucidated results that Au–C[Formula: see text]Li4–Au and Au–C[Formula: see text]Ne4–Au devices behave as an ordinary p–n junction diode and a Zener diode, respectively. Moreover, these doped fullerene molecules do not lose their metallic nature when sandwiched between the pair of gold electrodes.
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41

Erden Gulebaglan, Sinem, and Emel Kilit Dogan. "A comparison study of the structural electronic, elastic and lattice dynamic properties of ZrInAu and ZrSnPt." Zeitschrift für Naturforschung A 76, no. 6 (April 12, 2021): 559–67. http://dx.doi.org/10.1515/zna-2021-0014.

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Abstract To estimate the structural, electronic, elastic and dynamic properties of ZrInAu and ZrSnPt compounds, the density functional theory within the general gradient approximation was used. The computed lattice parameters, bulk modulus and the derivation of bulk modulus with respect to pressure were displayed and compared with the theoretical result. The indirect band gap for ZrInAu was found to be 0.48 eV, and for ZrSnPt the indirect band gap was found as 1.01 eV. Elastic stiffness constants, bulk, shear and Young’s module, Poisson’s coefficients and Zener anisotropy factor are calculated. Elastic properties showed that the ZrSnPt compound is more durable than the ZrInAu compound. Phonon distribution curves and density of states were investigated using a density functional perturbation theory. Both ZrInAu and ZrSnPt compounds were demonstrated to be dynamically stable. The results of this study were obtained for the first time in the literature. These results will make an important contribution to the literature.
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42

Brown, Thomas S., Shukai Du, Hasan Eruslu, and Francisco-Javier Sayas. "Analysis of models for viscoelastic wave propagation." Applied Mathematics and Nonlinear Sciences 3, no. 1 (March 9, 2018): 55–96. http://dx.doi.org/10.21042/amns.2018.1.00006.

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AbstractWe consider the problem of waves propagating in a viscoelastic solid. For the material properties of the solid we consider both classical and fractional differentiation in time versions of the Zener, Maxwell, and Voigt models, where the coupling of different models within the same solid are covered as well. Stability of each model is investigated in the Laplace domain, and these are then translated to time-domain estimates. With the use of semigroup theory, some time-domain results are also given which avoid using the Laplace transform and give sharper estimates. We take the time to develop and explain the theory necessary to understand the relation between the equations we solve in the Laplace domain and those in the time-domain which are written using the language of causal tempered distributions. Finally we offer some numerical experiments that highlight some of the differences between the models and how different parameters effect the results.
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43

Zhu, Hui, N. E. Mastorakis, and Qingquan Lei. "Systems Theory: Simulation Analysis of Space Charge Generation Mechanisms in Transformer Oil under High Electric Field." International Journal of Circuits, Systems and Signal Processing 15 (January 19, 2021): 23–32. http://dx.doi.org/10.46300/9106.2021.15.3.

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Simulation analysis plays an important role in Systems Theory nowadays. In order to reveal the mechanism of space charge injection and generation in the process of liquid dielectric breakdown, the discharge of transformer oil between needle-plane electrodes under high electric field is studied. Based on the 2-D hydrodynamic model and Poisson equation of electric field, the system simulation model of oil discharge by different charge generation mechanism is established, based on which the inception and propagation process of discharge is simulated by COMSOL. By system simulation, the temporal and spatial distribution of the electric field intensity, space charge density, electric potential and temperature of transformer oil is obtained and deeply analyzed. The simulation results prove that the space charge generated by metal field emission and ionic disassociation are neither of the major factor for streamer formation in transformer oil, while the Zener molecular ionization and impact ionization are the major factors. Our research improves the understanding of the inception, propagation and breakdown process for discharge in transformer oil, and also the ionization mechanism in the liquid dielectric
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44

Wang, Enjiang, José M. Carcione, and Jing Ba. "Wave simulation in double-porosity media based on the Biot-Rayleigh theory." GEOPHYSICS 84, no. 4 (July 1, 2019): WA11—WA21. http://dx.doi.org/10.1190/geo2018-0575.1.

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We have developed a numerical algorithm for simulation of wave propagation in double-porosity media, where the pore space is saturated with a single fluid. Spherical inclusions embedded in a background medium oscillate to yield attenuation by mode conversion from fast P-wave energy to slow P-wave energy (mesoscopic or wave-induced fluid-flow loss). The theory is based on the Biot theory of poroelasticity and the Rayleigh model of bubble oscillations. The differential equation of the Biot-Rayleigh variable is approximated with the Zener mechanical model, which results in a memory-variable viscoelastic equation. These approximations are required to model mesoscopic losses arising from conversion of the fast P-wave energy to slow diffusive modes. The model predicts a relaxation peak in the seismic band, depending on the diameter of the patches, to model the attenuation level observed in rocks. The wavefield is obtained with a grid method based on the Fourier differential operator and a second-order time-integration algorithm. Because the presence of two slow quasistatic modes makes the differential equations stiff, a time-splitting integration algorithm is used to solve the stiff part analytically. The modeling has spectral accuracy in the calculation of the spatial derivatives.
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45

Whaley, P. W. "A Mathematical Model for Internal Friction and Local Fatigue Damage Based on Populations of Yielding Microelements." Journal of Vibration and Acoustics 109, no. 2 (April 1, 1987): 201–6. http://dx.doi.org/10.1115/1.3269415.

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A mathematical model for internal friction and fatigue damage based on populations of yielding microelements is described. Using two parameters, the model accounts for amplitude dependence of material damping. For low excitation levels the Zener theory of thermoelasticity is reproduced. The significance of this new damping model is that fatigue damage due to local accumulations of microplastic deformation is quantified. The entropy production is defined by expressing the second law of thermodynamics for irreversible processes as an equality, and quantifying local accumulations of microplastic strain energy as the source of irreversibility. A critical entropy threshold is defined in terms of the local microplastic strain energy density of local failure. The hypothesis is offered that local fatigue damage leading to crack nucleation occurs by exceeding the critical entropy threshold.
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46

Lazopoulos, Anastassios K., and Dimitrios Karaoulanis. "On Λ-Fractional Viscoelastic Models." Axioms 10, no. 1 (February 20, 2021): 22. http://dx.doi.org/10.3390/axioms10010022.

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Λ-Fractional Derivative (Λ-FD) is a new groundbreaking Fractional Derivative (FD) introduced recently in mechanics. This derivative, along with Λ-Transform (Λ-T), provides a reliable alternative to fractional differential equations’ current solving. To put it straightforwardly, Λ-Fractional Derivative might be the only authentic non-local derivative that exists. In the present article, Λ-Fractional Derivative is used to describe the phenomenon of viscoelasticity, while the whole methodology is demonstrated meticulously. The fractional viscoelastic Zener model is studied, for relaxation as well as for creep. Interesting results are extracted and compared to other methodologies showing the value of the pre-mentioned method.
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47

Ivins, Erik R., Lambert Caron, Surendra Adhikari, and Eric Larour. "Notes on a compressible extended Burgers model of rheology." Geophysical Journal International 228, no. 3 (October 30, 2021): 1975–91. http://dx.doi.org/10.1093/gji/ggab452.

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SUMMARY Constitutive theory for viscoelasticity has broad application to solid mantle or ice deformations driven by tides, surface mass variations, and post-seismic flow. Geophysical models using higher order viscoelasticity can better accommodate geodetic observations than lower-order theory, typically provided by tensor versions of Maxwell, 4-parameter Burgers or standard linear (Zener) rheology. We derive, for the first time, a mathematical description of a compressible version of the extended Burgers material (EBM) model paradigm which has a distribution function of relaxation spectra. The latter model is often used for parametrizing high temperature background transient responses in the rock physics and mechanics laboratory setting and have demonstrated application to low frequency seismic wave attenuation. A new generalization of this practical anelastic model is presented and applied to the glacial isostatic adjustment momentum equations, thus providing useful guidance for generating initial-value boundary problem-solving software for quite general coding strategies. The solutions for the vertical motion response to a suddenly imposed surface load reveal a short-term transience of substantial amplitude.
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48

Wu, Feng, and Yuan Ping. "Combining Landau–Zener theory and kinetic Monte Carlo sampling for small polaron mobility of doped BiVO4 from first-principles." Journal of Materials Chemistry A 6, no. 41 (2018): 20025–36. http://dx.doi.org/10.1039/c8ta07437b.

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49

TAILLEUX, RÉMI, and JAMES C. McWILLIAMS. "Energy propagation of long extratropical Rossby waves over slowly varying zonal topography." Journal of Fluid Mechanics 473 (December 10, 2002): 295–319. http://dx.doi.org/10.1017/s0022112002002422.

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In classical WKB theory the only way wave energy density, as a surrogate for wave action density, can increase or decrease along a ray is as a result of the ray focusing or widening. This occurs when the group velocity is divergent. There are particular regions, however, where the wave can resonantly exchange action with another wave mode with approximately the same wavenumbers; a situation known as Landau–Zener transition, mode conversion, linear (adiabatic) resonance, etc. This effect invalidates locally the underlying assumption of WKB theory that no scattering of energy occurs between WKB wave modes. In this paper this effect is investigated theoretically for free long baroclinic Rossby waves in a two-layer planetary geostrophic model of the ocean with a purely zonal topography, here taken as a Gaussian ridge. The waves are excited along the east coast by an unspecified wavemaker at a fixed frequency ω. In the computation considered, mode conversion is found to occur principally near the ridge’s top and on the eastern flank. The predictions of mode conversion theory are tested against the results of direct numerical simulations. This shows excellent agreement, both for the locations of mode conversion points, and for the amplitude of the transmitted and converted WKB wave modes.
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50

Craus, M. L., N. Cornei, and T. L. To. "Low-Doped La0.54Ho0.11Sr0.35Mn1-XVxO3 Manganites: Vanadium Influence on Transport Phenomena and Magnetic Properties." Solid State Phenomena 190 (June 2012): 85–88. http://dx.doi.org/10.4028/www.scientific.net/ssp.190.85.

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Transport phenomena in manganites (ABO3), and indirectly the transition temperature from metallic to insulator state (TMI), can be controlled by hole doping and the average ionic size at A positions (). In agreement with Zener theory, the strength of double exchange is determined by the Mn-O length (dMnO) and Mn-O-Mn angles () of the Mn-O-Mn bonds. We will investigate the influence of substitution of Mn with V on the crystalline structure and transport characteristics in La0.54Ho0.11Sr0.35Mn1-xVxO3 manganites. The samples were prepared by sol-gel method to improve the purity and homogeneity of the samples. By XRD it was established that the samples contain only ABO3 perovskite phases, except the samples with x0.1. The resistance of the samples vs temperature was determined by four probes method. The specific magnetization was obtained by using a Foner type magnetometer, working at 1.4 T, between 77 and 400 K.
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