A New Kinetic Model for The Nucleation and Growth of Self-Interstitial Clusters in Silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
Christophe J. Ortiz ◽  
Daniel Mathiot
Keyword(s):  
Kinetic Model ◽  
Inverse Modeling ◽  
Nucleation And Growth ◽  
Experimental Results ◽  
Physical Parameters ◽  
Formation Energies ◽  
Good Agreement

ABSTRACTA model for nucleation and growth of {311} defects is proposed on the basis of thermodynamic and kinetic considerations. Simulated results are discussed and compared to experimental results found in the literature. According to our model it is found that formation energies of self-interstitial clusters depends on the local interstitial supersaturation. Physical parameters extracted from experimental results by inverse modeling are in good agreement with recent values published in the literature.

Determination of the limits of stable combustion at high supersonic flow velocities in a channel

2010 ◽  
Vol 3 (2) ◽  
pp. 47-60
Author(s):  
Alexey V. Starov
Keyword(s):  
Paper Analysis ◽  
Measurement Methods ◽  
Experimental Results ◽  
Physical Parameters ◽  
Supersonic Speed ◽  
Combustion Limits ◽  
Criterial Description ◽  
Selection Of ◽  
Good Agreement

In this paper, analysis of existing methods application of criterial description of ignition conditions and combustion break-out for summarizing of experimental results is carried out. Experimental results are obtained at investigations of hydrogen combustion in combustor with high supersonic speed of airflow. For these conditions selection of several criterions was substantiated and they have a good agreement with new experimental results. At the same time complexity of determination of experimental physical parameters, which are included in criterions, do not allow confidently to apply them for prediction of steady-state combustion limits. Therefore further accumulation of experimental data and development of measurement methods are necessary for accurate criterions obtaining.

Simulation of Dynamic Recrystallization for Ti-6.5Al-3.5Mo-1.5Zr-0.3Si Alloy in β Processed Using Cellular Automaton

2013 ◽  
Vol 634-638 ◽  
pp. 1781-1785
Author(s):  
Ke Lu Wang ◽  
Shi Qiang Lu ◽  
Xin Li ◽  
Xian Juan Dong
Keyword(s):  
Dynamic Recrystallization ◽  
Cellular Automaton ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
True Strain ◽  
Nucleation And Growth ◽  
Experimental Results ◽  
Physically Based ◽  
Good Agreement

The cellular automaton (CA) method coupling fundamental metallurgical principles was used to simulate the dynamic recrystallization (DRX) behavior of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy in β processed. Using physically based rules for the simulation of nucleation and growth phenomena of dynamically recrystallized grains. The effects of hot deformation temperature and true strain on the DRX characteristic of the alloy during β processed was studied, and the results compared with experiments. The predictions show very good agreement with the experimental results for the alloy.

Prediction of Silicide Formation Sequence from the Principle of the Largest Free Energy Degradation Rate

1993 ◽  
Vol 311 ◽  
Author(s):  
Lin Zhang ◽  
Douglas G. Ivey
Keyword(s):  
Free Energy ◽  
Kinetic Model ◽  
Degradation Rate ◽  
Diffusion Flux ◽  
Experimental Results ◽  
Silicide Formation ◽  
Change Rate ◽  
Energy Degradation ◽  
Generalized Kinetic Model ◽  
Good Agreement

ABSTRACTRecently, a generalized kinetic model for silicide formation has been developed and a principle of the largest free energy degradation rate (largest FEDR) has been proposed. Free energy change rate as a function of diffusion flux has been derived from the kinetic model so that the principle can be justified not only for first phase formation but also for the subsequent processes. Silicide formation sequence predictions, from the model and the FEDR principle, for 15 metal-Si systems have shown very good agreement with the experimental results reported in the literature. In this paper, a brief introduction to the model and the principle is given, followed by examples of the predictions for several metal-Si systems and comparison with experimental results.

scholarly journals Optimization of EDM Parameters for Production of Biomedical Materials

2021 ◽  
Vol 7 (2) ◽  
pp. 1-8
Author(s):  
Mukesh Kumar Rakesh ◽  
Dr. Syed Faisal Ahmed
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Solution ◽  
Literature Survey ◽  
Experimental Results ◽  
Physical Parameters ◽  
The Finite Element Method ◽  
Critical Areas ◽  
Cylindrical Cup ◽  
Good Agreement

The finite element method (FEM) is used for simulating complex intricate shapes of industrial sheet forming operation. Effective physical parameters, as well as the numerical solution, influence the parameters of this phenomenon and its numerical prediction of results. In this study, to investigate the influence of different embossing patterns and embossing depths on the critical areas appearing during deep-drawn of a cylindrical cup. The numerical results are found from the literature survey to be in good agreement with the experimental results and accurate thinning distributions had been predict.

New Semi-Empirical Method for Alloys

1992 ◽  
Vol 278 ◽  
Author(s):  
Guillermo Bozzolo ◽  
John Ferrante
Keyword(s):  
Defect Formation ◽  
Empirical Method ◽  
Experimental Results ◽  
New Method ◽  
Surface Energies ◽  
Computational Simplicity ◽  
Alloy Properties ◽  
Semi Empirical ◽  
Formation Energies ◽  
Good Agreement

AbstractWe introduce a new semi-empirical method for calculating alloy properties. The method Is based on the concepts of equivalent crystal theory of defect formation energies in elemental solids. With this new method we predict heats of formation, lattice parameters, surface energies, segregation senergies and other properties of several binary alloys of fcc (Cu, NI, Ag, Au, Al, Fe, Pd and Pt) and bcc (Cr, Mo, Fe, V) elements. The method is characterized for its extreme computational simplicity and good agreement with experimental results. Several applications of the method are discussed.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

Nitrate and chloride formation in chloramination

1994 ◽  
Vol 30 (9) ◽  
pp. 101-110
Author(s):  
V. Diyamandoglu
Keyword(s):  
Kinetic Model ◽  
Analytical Method ◽  
Kinetic Data ◽  
Experimental Results ◽  
Mass Balances ◽  
Time Profiles ◽  
Slow Decay ◽  
Concentration Time ◽  
End Products ◽  
Chlorine Residuals

The formation of nitrate and chloride as end-products of chloramination (combined chlorination) was investigated at pH ranging between 6.9 and 9.6 at 25°C. The experimental results comprised concentration-time profiles of combined chlorine residuals along with nitrate and chloride. Nitrite, if present, was always below the detectibility limit of the analytical method used (25 ppb). Mass balances on chlorine species depicted that chloride formed during the slow decay of combined chlorine residuals does not account for all the chlorine lost. This substantiates the formation of other reaction end-products which are yet to be identified. A kinetic model for chloramination is proposed based on the kinetic data obtained in this study.

The study of acoustic scattering from a single sound-permeable sphere

2018 ◽  
Vol 13 (4) ◽  
pp. 79-91 ◽  
Author(s):  
E.Sh. Nasibullaeva
Keyword(s):  
Speed Of Sound ◽  
Numerical Technique ◽  
Acoustic Scattering ◽  
Computer Time ◽  
Physical Parameters ◽  
Fast Method ◽  
Scattering Field ◽  
Permeable Sphere ◽  
Test Verification ◽  
Good Agreement

The paper presents a generalized mathematical model and numerical investigation of the problem of acoustic scattering from a single sound-permeable sphere during the passage of two types of waves - spherical from a monopole radiation source and a plane one. In solving the Helmholtz equation, a numerical technique based on the fast method of multipoles is used, which allows achieving high accuracy of the results obtained at the lowest cost of computer time. The calculations are compared with known experimental data and a good agreement is obtained. The formulas for calculating the main characteristic of the scattering field (the total scattering cross section) for a sound-permeable sphere are generalized. The effect on this characteristic of the physical parameters of media outside and inside the sphere, such as the density and speed of sound, is shown. A numerical parametric analysis of the pressure distribution around a single sound-permeable sphere for different values of the wave radius, density, and speed of sound of the outer and inner medium of the sphere is carried out. The obtained results will later be used for test verification calculations for the numerical solution of the generalized problem of acoustic scattering of a set of sound-permeable spheres (coaxial or arbitrarily located in space).

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

Sign in / Sign up

Export Citation Format

Share Document