Non-Linear and Time-Dependent Diffusion of Gold in Amorphous Silicon.

1991 ◽  
Vol 235 ◽  
Author(s):  
A. V. Wagner ◽  
D. T. Wu ◽  
F. Spaepen
Keyword(s):  
Diffusion Coefficient ◽  
Amorphous Silicon ◽  
Concentration Profile ◽  
Master Curve ◽  
Activation Enthalpy ◽  
Time Dependent ◽  
Second Moment ◽  
Non Linear

ABSTRACTBy performing scaling experiments [1] and examining the evolution of the spatial second moment of the concentration profile, it was shown that the diffusion coefficient of gold in amorphous silicon is both concentration and time dependent. The second moment curves for different temperature anneals can be scaled to a master curve using a factor with an activation enthalpy of 2.0 eV.

scholarly journals Time-Dependent Diffusion Coefficients for Chaotic Advection due to Fluctuations of Convective Rolls

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 99 ◽  
Author(s):  
Kazuma Yamanaka ◽  
Takayuki Narumi ◽  
Megumi Hashiguchi ◽  
Hirotaka Okabe ◽  
Kazuhiro Hara ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Liquid Crystals ◽  
Diffusion Coefficients ◽  
Coarse Graining ◽  
Chaotic Advection ◽  
Time Dependent ◽  
Local Order ◽  
Weak Turbulence ◽  
Normal Diffusion ◽  
Convective Rolls

The properties of chaotic advection arising from defect turbulence, that is, weak turbulence in the electroconvection of nematic liquid crystals, were experimentally investigated. Defect turbulence is a phenomenon in which fluctuations of convective rolls arise and are globally disturbed while maintaining convective rolls locally. The time-dependent diffusion coefficient, as measured from the motion of a tagged particle driven by the turbulence, was used to clarify the dependence of the type of diffusion on coarse-graining time. The results showed that, as coarse-graining time increases, the type of diffusion changes from superdiffusion → subdiffusion → normal diffusion. The change in diffusive properties over the observed timescale reflects the coexistence of local order and global disorder in the defect turbulence.

Time dependent diffusion coefficient in a disordered medium

1996 ◽  
Vol 104 (1) ◽  
pp. 206-209 ◽  
Author(s):  
Thomas M. de Swiet ◽  
Pabitra N. Sen
Keyword(s):  
Diffusion Coefficient ◽  
Time Dependent ◽  
Disordered Medium

A Mechanism of Polycrystallization in Fully Lamellar Ti-48Al-8Nb Single Crystal Alloy Aged at Elevated Temperatures

2002 ◽  
Vol 753 ◽  
Author(s):  
Yukinori Yamamoto ◽  
Masao Takeyama ◽  
Takashi Matsuo
Keyword(s):  
Growth Rate ◽  
Diffusion Coefficient ◽  
Single Crystal ◽  
Grain Growth ◽  
Elevated Temperatures ◽  
Volume Diffusion ◽  
Activation Enthalpy ◽  
Lamellar Microstructure ◽  
Aged Sample ◽  
Fully Lamellar

ABSTRACTPolycrystallization mechanism of a fully lamellar microstructure during aging at 1473 and 1273 K has been examined using Ti-48Al-8Nb fully lamellar single crystal, which consists mostly of γ/γ interfaces (variant, perfect-twin and pseudo-twin boundaries). After a certain period of aging, a few γ grains are formed within the lamellae and the lamellar microstructure collapses rapidly to become a γ grained microstructure at both temperatures. An EBSP analysis for aged sample revealed that most of the grains follow the orientation of variant domains in the lamellar microstructure. A kinetic analysis of the grain growth during aging revealed that the activation enthalpy of the growth rate is estimated to be 390 kJ/mol, which is very close to that for volume diffusion coefficient of Al and Nb in γ-TiAl. Based on the results, it is concluded that the formation of the grains is attributed to coarsening of variant domains within the lamellar plates and coalescence of the same variant domains across the lamellae, leading to a γ grained microstructure following the orientation of variant domains. These reactions also make the number of the variant domains decrease during aging, which remains only two variant domains with perfect-twin relationship.

Non-Linear Proportional Default Model with Time-Dependent Variable for Retail Loan

2009 ◽  
Vol 29 (11) ◽  
pp. 60-66 ◽  
Author(s):  
Jian-gang PENG ◽  
Zhang-fei LI ◽  
Zhi-hua LV ◽  
Hong-wei ZHOU
Keyword(s):  
Time Dependent ◽  
Default Model ◽  
Non Linear
Sign in / Sign up

Export Citation Format

Share Document