نتایج جستجو برای: diffusion theory

تعداد نتایج: 931990  

Journal: :Applied optics 2004
Sébastien Massenot Jean-Luc Kaiser Raymond Chevallier Yvon Renotte

Local and nonlocal models for the diffusion of photopolymers are applied to the dynamic formation of transmission gratings recorded in photopolymers and holographic polymer-dispersed liquid crystals (H-PDLCs). We retrieve the main parameters of H-PDLCs (refractive-index modulation and diffusion coefficient) by combining a solution of the one-dimensional diffusion equation and the rigorous coupl...

Journal: :Journal of the American Chemical Society 2008
Shao-Chun Li Zhenrong Zhang Daniel Sheppard Bruce D Kay J M White Yingge Du Igor Lyubinetsky Graeme Henkelman Zdenek Dohnálek

The combined experimental and theoretical study of intrinsic hydrogen diffusion on bridge-bonded oxygen (BBO) rows of TiO 2(110) is presented. Sequences of isothermal scanning tunneling microscopy images demonstrate a complex behavior of hydrogen formed by water dissociation on BBO vacancies. Different diffusion rates are observed for the two hydrogens in the original geminate OH pair suggestin...

2016
Peiyu Ren Yancang Li Huiping Song Jian Tan

Supply chain network enables the enterprises to achieve the purpose of knowledge diffusion complementary. Based on the complex network theory, using the method of combining qualitative analysis and model deduction, we established a knowledge diffusion network model that view staff of supply chain as network node, discussed the mechanism of knowledge diffusion, analysed the main control paramete...

2017
Xiaoying Qi

This article argues that the diffusion of concepts and theories from one culture or society to another requires the active engagement of a category of agents which I identify as ‘intellectual entrepreneurs’. Two historically contrasting cases of the transmission of ideas are examined in order to explain the processes whereby alien concepts are diffused across cultures. Foreign ideas and concept...

Journal: :Psychological review 1987
R Ratcliff

The account given by the diffusion model (Ratcliff, 1985) of the relation between positive and negative responses has been criticized by Proctor, who argues that the diffusion model provides no theory of criterion setting and that it violates psychophysical principles. In reply, I argue that psychophysical principles are not violated and that a quantitative theory of criterion placement is curr...

2006
S. H. Lam

The derivation of the multicomponent diffusion law is revisited. Following Furry Am. J. Phys. 16, 63 1948 , Williams Am. J. Phys. 26, 467 1958 ; Combustion Theory, 2nd ed. Benjamin/ Cummings , Menlo Park, CA,1985 heuristically rederived the classical kinetic theory results using macroscopic equations, and pointed out that the dynamics of the mixture fluid had been assumed inviscid. This paper g...

2015
Bi-Cheng Zhou Shun-Li Shang Yi Wang Zi-Kui Liu

Diffusion coefficients of alloying elements in Mg are critical for the development of new Mg alloys for lightweight applications. Here we present the data set of the temperature-dependent dilute tracer diffusion coefficients for 47 substitutional alloying elements in hexagonal closed packed (hcp) Mg calculated from first-principles calculations based on density functional theory (DFT) by combin...

2006
Juan Luis Vázquez

We review some topics in the mathematical theory of nonlinear diffusion. Attention is focused on the porous medium equation and the fast diffusion equation, including logarithmic diffusion. Special features are the existence of free boundaries, the limited regularity of the solutions and the peculiar asymptotic laws for porous medium flows, while for fast diffusions we find the phenomena of fin...

Journal: :The Journal of chemical physics 2009
Sergio Alonso Markus Bär Raymond Kapral

An effective medium theory that can be used to calculate effective diffusion and reaction rate coefficients in random heterogeneous reaction-diffusion systems is described. The predictions of the theory are compared with simulations of spatially distributed media with different types of heterogeneity. The magnitude of the front velocity in bistable media is used to gauge the accuracy of the the...

2002
S. SHAO

We study a family of diffusion models for risk reserves which account for the investment income earned and for the inflation experienced on claim amounts. After we defined the process of the conditional probability of ruin over finite time and imposed the appropriate boundary conditions, classical results from the theory of diffusion processes turn the stochastic differential equation to a spec...

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