Epitaxial Growth in Dislocation-Free Strained Alloy Films

2002 ◽  
Vol 715 ◽  
Author(s):  
Zhi-Feng Huang ◽  
Rashmi C. Desai
Keyword(s):  
Deposition Rate ◽  
Elastic Moduli ◽  
Composition Dependence ◽  
Critical Thickness ◽  
Lattice Misfit ◽  
Misfit Strain ◽  
Joint Stability ◽  
Alloy Films ◽  
The Stability ◽  
Stability Results

AbstractThe morphological and compositional instabilities in the heteroepitaxial strained alloy films have attracted intense interest from both experimentalists and theorists. To understand the mechanisms and properties for the generation of instabilities, we have developed a nonequilibrium, continuum model for the dislocation-free and coherent film systems. The early evolution processes of surface pro.les for both growing and postdeposition (non-growing) thin alloy films are studied through a linear stability analysis. We consider the coupling between top surface of the film and the underlying bulk, as well as the combination and interplay of different elastic effects. These e.ects are caused by filmsubstrate lattice misfit, composition dependence of film lattice constant (compositional stress), and composition dependence of both Young's and shear elastic moduli. The interplay of these factors as well as the growth temperature and deposition rate leads to rich and complicated stability results. For both the growing.lm and non-growing alloy free surface, we determine the stability conditions and diagrams for the system. These show the joint stability or instability for film morphology and compositional pro.les, as well as the asymmetry between tensile and compressive layers. The kinetic critical thickness for the onset of instability during.lm growth is also calculated, and its scaling behavior with respect to misfit strain and deposition rate determined. Our results have implications for real alloy growth systems such as SiGe and InGaAs, which agree with qualitative trends seen in recent experimental observations.

An analysis of the transport properties and mechanical stability of rapidly solidified Al-Sb alloy

2015 ◽  
Vol 10 (2) ◽  
pp. 2663-2681
Author(s):  
Rizk El- Sayed ◽  
Mustafa Kamal ◽  
Abu-Bakr El-Bediwi ◽  
Qutaiba Rasheed Solaiman
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Melt Spinning ◽  
Elastic Moduli ◽  
Mechanical Stability ◽  
Microstructural Analysis ◽  
Alloy System ◽  
Antimony Content ◽  
The Stability ◽  
Rapidly Solidified

The structure of a series of AlSb alloys prepared by melt spinning have been studied in the as melt–spun ribbons  as a function of antimony content .The stability  of these structures has  been  related to that of the transport and mechanical properties of the alloy ribbons. Microstructural analysis was performed and it was found that only Al and AlSb phases formed for different composition.  The electrical, thermal and the stability of the mechanical properties are related indirectly through the influence of the antimony content. The results are interpreted in terms of the phase change occurring to alloy system. Electrical resistivity, thermal conductivity, elastic moduli and the values of microhardness are found to be more sensitive than the internal friction to the phase changes. 

scholarly journals Analysis of dengue model with fractal-fractional Caputo–Fabrizio operator

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Fatmawati ◽  
Muhammad Altaf Khan ◽  
Cicik Alfiniyah ◽  
Ebraheem Alzahrani
Keyword(s):  
Statistical Data ◽  
Dengue Infection ◽  
Fractional Operator ◽  
Novel Approach ◽  
Reduction Number ◽  
Best Fitting ◽  
The Stability ◽  
Parameter Values ◽  
Graphical Illustration ◽  
Stability Results

AbstractIn this work, we study the dengue dynamics with fractal-factional Caputo–Fabrizio operator. We employ real statistical data of dengue infection cases of East Java, Indonesia, from 2018 and parameterize the dengue model. The estimated basic reduction number for this dataset is $\mathcal{R}_{0}\approx2.2020$ R 0 ≈ 2.2020 . We briefly show the stability results of the model for the case when the basic reproduction number is $\mathcal{R}_{0} <1$ R 0 < 1 . We apply the fractal-fractional operator in the framework of Caputo–Fabrizio to the model and present its numerical solution by using a novel approach. The parameter values estimated for the model are used to compare with fractal-fractional operator, and we suggest that the fractal-fractional operator provides the best fitting for real cases of dengue infection when varying the values of both operators’ orders. We suggest some more graphical illustration for the model variables with various orders of fractal and fractional.

scholarly journals Boundary Stabilization of a Semilinear Wave Equation with Variable Coefficients under the Time-Varying and Nonlinear Feedback

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Bei Gong ◽  
Xiaopeng Zhao
Keyword(s):  
Wave Equation ◽  
Riemannian Geometry ◽  
Nonlinear Term ◽  
Variable Coefficients ◽  
Time Varying ◽  
Nonlinear Feedback ◽  
Boundary Stabilization ◽  
Semilinear Wave Equation ◽  
The Stability ◽  
Stability Results

We study the boundary stabilization of a semilinear wave equation with variable coefficients under the time-varying and nonlinear feedback. By the Riemannian geometry methods, we obtain the stability results of the system under suitable assumptions of the bound of the time-varying term and the nonlinearity of the nonlinear term.

Thermal Stability of Strained InGaAs/GaAs Single Quantum Wells

1989 ◽  
Vol 160 ◽  
Author(s):  
B. Elman ◽  
Emil S. Koteles ◽  
P. Melman ◽  
C.A. Armiento ◽  
C. Jagannath
Keyword(s):  
Thermal Stability ◽  
Quantum Wells ◽  
Molecular Beam ◽  
Critical Thickness ◽  
Single Quantum ◽  
Furnace Annealing ◽  
Low Dislocation Density ◽  
The Stability ◽  
Thermal Stability Of ◽  
Low Temperature Photoluminescence

AbstractWe present a study of the structural stability of InGaAs/GaAs strained single quantum wells (SQW) grown with a variety of indium compositions and with well widths close to critical thickness values. The samples were grown by molecular beam epitaxy and were subjected to furnace annealing as well as ion implantation followed by rapid thermal annealing. Changes in low temperature photoluminescence linewidths were used to evaluate the stability of strained SQWs. We observed both strain relief, in wide SQWs and strain recovery, in higher indium composition narrow quantum wells which were partially relaxed (low dislocation density) as-grown.

scholarly journals On the probabilistic stability of some functional equations

2013 ◽  
Vol 29 (1) ◽  
pp. 125-132
Author(s):  
CLAUDIA ZAHARIA ◽  
◽  
DOREL MIHET ◽  
Keyword(s):  
Fixed Point ◽  
Functional Equations ◽  
Fixed Point Theory ◽  
Point Theory ◽  
Quadratic Functional ◽  
Normed Spaces ◽  
Stability Of Functional Equations ◽  
The Stability ◽  
Stability Results

We establish stability results concerning the additive and quadratic functional equations in complete Menger ϕ-normed spaces by using fixed point theory. As particular cases, some theorems regarding the stability of functional equations in β - normed and quasi-normed spaces are obtained.

Electrocaloric Effect of (110) Oriented KNbO3 Film

2021 ◽  
Vol 21 (10) ◽  
pp. 5247-5252
Author(s):  
MinYa Jin ◽  
JianHua Qiu ◽  
ZhiHui Chen ◽  
XiuQin Wang ◽  
NingYi Yuan ◽  
...  
Keyword(s):  
Electric Field ◽  
Thermodynamic Equilibrium ◽  
Thermodynamic Potential ◽  
Room Temperature ◽  
Misfit Strain ◽  
Equilibrium Conditions ◽  
Electrocaloric Effect ◽  
Phase Map ◽  
The Stability

The room temperature electrocaloric effect is researched for (110) oriented KNbO3 film based on Landau-Devonshire theory. The phase map with different ferroelectric states is built at room temperature with the considerations of thermodynamic equilibrium conditions and minimum of thermodynamic potential. Five ferroelectric structural phases are obtained theoretically. The negative in-plane misfit strains are conducive to form the tetragonal c phase and the positive strains are in favor of the stability of tetragonal a1 and a2 phases. The electrocaloric effect relies on both misfit strain and electric field. Moreover, large electrocaloric effect is achieved in the orthorhombic phases.

scholarly journals On Cauchy’s Interlacing Theorem and the Stability of a Class of Linear Discrete Aggregation Models Under Eventual Linear Output Feedback Controls

Symmetry ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 712 ◽  
Author(s):  
Manuel De la Sen
Keyword(s):  
Dynamic System ◽  
Output Feedback ◽  
Iteration Step ◽  
Stability And Convergence ◽  
Feedback Controls ◽  
Time Aggregation ◽  
The Stability ◽  
The Given ◽  
Stability Results

This paper links the celebrated Cauchy’s interlacing theorem of eigenvalues for partitioned updated sequences of Hermitian matrices with stability and convergence problems and results of related sequences of matrices. The results are also applied to sequences of factorizations of semidefinite matrices with their complex conjugates ones to obtain sufficiency-type stability results for the factors in those factorizations. Some extensions are given for parallel characterizations of convergent sequences of matrices. In both cases, the updated information has a Hermitian structure, in particular, a symmetric structure occurs if the involved vector and matrices are complex. These results rely on the relation of stable matrices and convergent matrices (those ones being intuitively stable in a discrete context). An epidemic model involving a clustering structure is discussed in light of the given results. Finally, an application is given for a discrete-time aggregation dynamic system where an aggregated subsystem is incorporated into the whole system at each iteration step. The whole aggregation system and the sequence of aggregated subsystems are assumed to be controlled via linear-output feedback. The characterization of the aggregation dynamic system linked to the updating dynamics through the iteration procedure implies that such a system is, generally, time-varying.

Complexity factor for dynamical spherically symmetric fluid distributions in f(R) gravity

2019 ◽  
Vol 16 (11) ◽  
pp. 1950170
Author(s):  
H. Nazar ◽  
G. Abbas
Keyword(s):  
Physical Nature ◽  
The Self ◽  
Fluid Distribution ◽  
Spherically Symmetric ◽  
Static Case ◽  
System Configuration ◽  
Prior Investigation ◽  
Text Model ◽  
The Stability ◽  
Stability Results

In this study, we analyze the complexity factor that is extended up to the dynamical spherically symmetric non-static case with anisotropic dissipative self-gravitating fluid distribution in context of [Formula: see text] theory of gravity. For this evaluation we choose the particular [Formula: see text] model that signifies the physical nature of the self-gravitating system. The proposed work discusses not only the complexity factor of the structure of the fluid distribution, but also defines the minimization rate of complexity of the pattern of evolution. Here, first we have applied similar approach for obtaining the structure scalar [Formula: see text] of the complexity factor as used for in the static case, and next we have described explicitly the dissipative and non-dissipative cases by assuming the simplest pattern of evolution (homologous condition). It has been found that the system configuration fulfills the vanishing condition of complexity factor and emerging homologously, corresponds to a energy density homogeneity, shearfree and geodesic, isotropic in pressure. Moreover, we define the stability results for the vanishing complexity factor condition. Finally, we would like to mention that these results are satisfying the prior investigation about complexity factor in General Relativity (GR) by setting [Formula: see text].

Development of Microemulsions Containing Carthamus tinctorius Extract for 5α-Reductase Inhibition

2019 ◽  
Vol 819 ◽  
pp. 92-97
Author(s):  
Sitthiphong Soradech ◽  
Khaunnapa Panapong ◽  
Surada Soonthornsatitwong ◽  
Somkamol Manchun ◽  
Sirinan Tubtimted ◽  
...  
Keyword(s):  
Transdermal Delivery ◽  
Reductase Activity ◽  
Skin Permeation ◽  
Carthamus Tinctorius ◽  
Permeation Rate ◽  
Du145 Cells ◽  
Thai Medicinal Plants ◽  
The Stability ◽  
Stability Results

The purpose of this study was to develop micromeulsion consisting of Carthamus tinctorius floret extract (CT) as an ingredient to inhibit 5α-reductase activity. CT was extracted using a simple maceration technique with ethanol and inhibition of 5α-reductase activities was determined. Solutions of 2% CT extract were loaded into four microemulsion (ME) formulas (F1, F2, F3 and F4) and investigated for their physical properties, skin permeation and stability. Results showed that crude CT extract had no toxic effects on DU145 cells at concentrations of 0.0001-1.0 mg/mL. For reduction of 5α-reductase activities, concentration of CT extract at 0.05 mg/mL exhibited highest 5-reductase type-1 inhibition activity on the DU-145 cell line at 89.96% of the control, higher than standard finasteride (31.39%) and dutasteride (38.58%). The results indicated that a thermodynamically stable microemulsion improved the stability and permeation rate of CT extract. Among the ME formula, F3 was most appropriate for ME formulation with highest permeation rate and good stability during 30 days of storage. Therefore, using nanotechnology for stable transdermal delivery systems of bioactive compounds from Thai medicinal plants is one approach to improve skin and hair follicle permeation.

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