翻訳と辞書 Words near each other ・ May 1968 tornado outbreak ・ May 1971 ・ May 1972 ・ May 1973 ・ May 1975 ・ May 1975 lunar eclipse ・ May 1976 lunar eclipse ・ Maxwellton Station, Nova Scotia ・ Maxwellton, Saskatchewan ・ Maxwelltown ・ Maxwelltown High School ・ Maxwell–Boltzmann ・ Maxwell–Boltzmann distribution ・ Maxwell–Boltzmann statistics ・ Maxwell–Jüttner distribution ・ Maxwell–Stefan diffusion ・ Maxwell–Wagner–Sillars polarization ・ Maxwelton ・ Maxwelton, Queensland ・ Maxwelton, Washington ・ Maxwelton, West Virginia ・ Maxworthy ・ Maxx ・ Maxx (band) ・ MAXX (brand) ・ Maxx (film) ・ MAXX Factor ・ Maxx Klaxon ・ Maxx Payne ・ Maxx Williams Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Maxwell–Stefan diffusion ： ウィキペディア英語版 Maxwell–Stefan diffusion The Maxwell–Stefan diffusion (or Stefan–Maxwell diffusion) is a model for describing diffusion in multicomponent systems. The equations that describe these transport processes have been developed independently and in parallel by James Clerk Maxwell〔J. C. Maxwell: ''On the dynamical theory of gases'', The Scientific Papers of J. C. Maxwell, 1965, 2, 26–78.〕 for dilute gases and Josef Stefan〔J. Stefan: ''Über das Gleichgewicht und Bewegung, insbesondere die Diffusion von Gemischen'', Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften Wien, 2te Abteilung a, 1871, 63, 63-124.〕 for fluids. The Maxwell–Stefan equation is : :$$ \frac = \nabla \ln a_i ==\sum_^_}(\vec v_j-\vec v_i)} ==\sum_^_}\left(\frac-\frac\right)} * ∇: vector differential operator * χ: Mole fraction * μ: Chemical potential * a: Activity * i, j: Indexes for component i and j * n: Number of components * $\backslash mathfrak\_$: Maxwell–Stefan-diffusion coefficient * $\backslash vec\; v\_i$: Diffusion velocity of component i * $c\_i$: Molar concentration of component i * c: Total molar concentration * $\backslash vec\; J\_i$: Flux of component i The equation assumes steady state, that is the absence of velocity gradients. The basic assumption of the theory is that a deviation from equilibrium between the molecular friction and thermodynamic interactions leads to the diffusion flux.〔S. Rehfeldt, J. Stichlmair: ''Measurement and calculation of multicomponent diffusion coefficients in liquids'', Fluid Phase Equilibria, 2007, 256, 99–104〕 The molecular friction between two components is proportional to their difference in speed and their mole fractions. In the simplest case, the gradient of chemical potential is the driving force of diffusion. For complex systems, such as electrolytic solutions, and other drivers, such as a pressure gradient, the equation must be expanded to include additional terms for interactions. A major disadvantage of the Maxwell–Stefan theory is that the diffusion coefficients, with the exception of the diffusion of dilute gases, do not correspond to the Fick's diffusion coefficients and are therefore not tabulated. Only the diffusion coefficients for the binary and ternary case can be determined with reasonable effort. In a multicomponent system, a set of approximate formulas exist to predict the Maxwell–Stefan-diffusion coefficient.〔 The Maxwell–Stefan theory is more comprehensive than the "classical" Fick's diffusion theory, as the former does not exclude the possibility of negative diffusion coefficients. It is possible to derive Fick's theory from the Maxwell–Stefan theory.〔 ==See also== *Pervaporation 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Maxwell–Stefan diffusion」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.