A Dynamic Model of III-V Ternary Semiconductor Alloys in the Epitaxial Growth

1994 ◽  
Vol 340 ◽  
Author(s):  
Bing-Lin Gu ◽  
Jing-Zhi Yu ◽  
Xiao Hu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Dynamic Model ◽  
Ground State ◽  
Wave Method ◽  
Semiconductor Alloys ◽  
Concentration Wave ◽  
Surface Layers ◽  
Ordered Structures ◽  
Effective Interactions ◽  
Ternary Semiconductor ◽  
The Difference

ABSTRACTA concentration wave method for several interpenetrating Bravais sublattices is presented by considering the intralayer and interlayer effective interactions and the difference between the surface layers and the deeper layers in III – V alloys. The ground state ordered structures of ternary III – V semiconductor alloys are deduced and a dynamic model is established.

THE ANGULAR MOMENTUM DEPENDENT CALCULATION OF THE GROUND STATE ENERGY OF LIQUID 3He

2005 ◽  
Vol 19 (30) ◽  
pp. 1793-1802 ◽  
Author(s):  
M. MODARRES
Keyword(s):  
Angular Momentum ◽  
Ground State Energy ◽  
Ground State ◽  
Correlation Functions ◽  
State Energy ◽  
Interatomic Potentials ◽  
Channel Correlation ◽  
P Waves ◽  
Effective Interactions ◽  
Three Body

We investigate the possible angular momentum, l, dependence of the ground state energy of normal liquid 3 He . The method of lowest order constrained variational (LOCV) which includes the three-body cluster energy and normalization constraint (LOCVE) is used with angular momentum dependent two-body correlation functions. A functional minimization is performed with respect to each l-channel correlation function. It is shown that this dependence increases the binding energy of liquid 3 He by 8% with respect to calculations without angular momentum dependent correlation functions. The l=0 state has completely different behavior with respect to other l-channels. It is also found that the main contribution from potential energy comes from the l=1 state (p-waves) and the effect of l≥11 is less than about 0.1%. The effective interactions and two-body correlations in different channels are being discussed. Finally we conclude that this l-dependence can be verified experimentally by looking into the magnetization properties of liquid helium 3 and interatomic potentials.

Robust Control of the Elastodynamic Vibrations of a Flexible Rotor System With Discontinuous Friction

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Mansour Karkoub
Keyword(s):  
Dynamic Model ◽  
Design Process ◽  
Nonlinear Models ◽  
Control Design ◽  
Rotor System ◽  
Control Technique ◽  
Flexible Rotor ◽  
Highly Nonlinear ◽  
Modeling Errors ◽  
The Difference

The work presented here deals with the control of a flexible rotor system using the μ-synthesis control technique. This technique allows for the inclusion of modeling errors in the control design process in terms of uncertainty weights. The dynamic model of the rotor system, which includes discontinuous friction, is highly nonlinear and has to be linearized around an operating point in order to use μ-synthesis. The difference between the linear and nonlinear models is characterized in terms of uncertainty weights and included in the control design process. The designed controller is robust to uncertainty in the dynamic model, spillover, actuator uncertainty, and noise. The theoretical findings of the μ-synthesis control design are validated through simulations and the results are presented and discussed here.

Mutual Passivation in Dilute GaNxAs1-x Alloys

2005 ◽  
Vol 864 ◽  
Author(s):  
K. M. Yu ◽  
W. Walukiewicz ◽  
J. Wu ◽  
D. E. Mars ◽  
M. A. Scarpulla ◽  
...  
Keyword(s):  
Nearest Neighbor ◽  
Diffusion Length ◽  
Average Distance ◽  
Alloy System ◽  
Group Iv ◽  
Semiconductor Alloys ◽  
Drastic Reduction ◽  
Free Electron Concentration ◽  
Ternary Semiconductor ◽  
Good Agreement

AbstractThe dilute GaNxAs1-x alloys (with x up to 0.05) have exhibited many unusual properties as compared to the conventional binary and ternary semiconductor alloys. We report on a new effect in the GaNxAs1-x alloy system in which electrically active substitutional group IV donors and isoelectronic N atoms passivate each other's activity. This mutual passivation occurs in dilute GaNxAs1-x doped with group IV donors through the formation of nearest neighbor IVGa- NAs pairs when the samples are annealed under conditions such that the diffusion length of the donors is greater than or equal to the average distance between donor and N atoms. The passivation of the shallow donors and the NAs atoms is manifested in a drastic reduction in the free electron concentration and, simultaneously, an increase in the fundamental bandgap. This mutual passivation effect is demonstrated in both Si and Ge doped GaNxAs1-x alloys. Analytical calculations of the passivation process based on Ga vacancy mediated diffusion show good agreement with the experimental results.

Basic Theory of Simplified Dynamic Model for Spherical Tank Considering Swinging Effect

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Yuan Lü ◽  
Jiangang Sun ◽  
Zongguang Sun ◽  
Lifu Cui ◽  
Zhen Wang
Keyword(s):  
Dynamic Model ◽  
Shear Force ◽  
Velocity Potential ◽  
Fluid Pressure ◽  
Site Conditions ◽  
Base Shear ◽  
Site Condition ◽  
Spherical Tank ◽  
Overturning Moment ◽  
The Difference

Abstract Consider the swinging effect of spherical tank, the theory of velocity potential is adopted, and a reasonable potential function is derived according to the boundary conditions. Further, the dynamic fluid pressure, the wave height of the liquid, the shear force and the overturning moment at the bottom of the spherical tank is calculated, and a simplified dynamic model of spherical tank considering liquid sloshing and swinging effect was constructed. The seismic response was studied and compared with the results without considering the swing effect. The results show that: for Ι, II site conditions, base shear force and overturning moment of considering the swing effect is slightly smaller than when nonconsidering and the difference rate between the two is very small. III–IV site conditions, each condition value of considering the swing effect is larger than when nonconsidering and the difference rate between the two is relatively large. Aseismic design of spherical tank and the influence of swing effect should be considered if the site condition is III and IV, and if site I and II, they can be ignored.

COLLECTIVE EXCITATIONS IN SEMICONDUCTOR AND GRAPHENE BILAYERS IN HIGH MAGNETIC FIELD

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2851-2855
Author(s):  
VERONIKA BISTI
Keyword(s):  
Magnetic Field ◽  
Charge Density ◽  
Ground State ◽  
Asymmetry Parameter ◽  
Filling Factor ◽  
Electron System ◽  
Collective Excitations ◽  
Graphene Layers ◽  
Space Symmetry ◽  
The Difference

The effect of space symmetry on magnetoplasmon charge density and spin-density excitations in a weakly tunnel coupled bilayer electron system at the filling factor ν = 4 is considered. The optic magnetoplasmon energy as well as the energy of intralayer magnetoexciton is not affected by space symmetry. Three other collective magnetoplasmon modes as well as three magnetoexciton modes are determined by relations between the asymmetry parameter, tunnel parameter, and the difference in energies of intralayer and interlayer magnetoexcitons. The charge-density excitations in bilayer graphene at the filling-factor ν ≪ 1 are considered. The presence of small asymmetry of graphene layers is taken into account. It is demonstarted that the magnetoplasmon energy depends on the bilayer ground state.

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