SELF-CONSISTENT APPROACH TO THE DIFFUSION INDUCED BY A CENTRIFUGAL FIELD IN CONDENSED MATTER - SEDIMENTATION
SELF-CONSISTENT APPROACH TO THE DIFFUSION INDUCED BY A CENTRIFUGAL FIELD IN CONDENSED MATTER - SEDIMENTATION
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DOI：
10.1103/physreva.38.4149
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发表时间：
1988-10-15
影响因子：
2.9
通讯作者：
MASHIMO, T
中科院分区：
文献类型：
--
作者：
MASHIMO, T
本文提出了一种Lamm沉降方程的自洽方法，用于描述双组分凝聚体系中离心（或重力）场引起的扩散，特别是对于高溶质浓度或高离心场。在这种方法中，诱导扩散的驱动力通过引入引起浮力的周围混合物（溶剂和溶质）的有效质量来表示。它自洽地表示为浓度的函数，而不是Lamm方程中的常数值。该理论建立在非平衡态热力学和能斯特-爱因斯坦关系的基础上，考虑了浓度变化的影响。由此产生的扩散方程的非线性形式，而不是线性的Lamm方程。通过求解非线性扩散方程，得到了平衡状态下的浓度分布。结果表明，非线性效应是显着的增加，无论是在溶质浓度或在离心力场。
A self-consistent approach to the Lamm sedimentation equation is proposed for describing the diffusion induced by a centrifugal (or gravitational) field in a two-component condensed system, particularly for a high solute concentration or a high centrifugal field. In this approach, the driving force inducing the diffusion is expressed by introduction of the effective mass of the surrounding mixture (solvent and solutes) which causes the buoyant force. It is self-consistently represented as a function of concentration in place of the constant value in the Lamm equation. The theory is constructed on the basis of nonequilibrium thermodynamics and the Nernst-Einstein relation considering the effect of concentration change. The resulting diffusion equation is presented in a nonlinear form instead of the linear one of the Lamm equation. The concentration profile in equilibrium state is found by solving the nonlinear diffusion equation. It is shown that the nonlinear effect is significant with increase either in the solute concentration or in the centrifugal field.