Migration laws

Equivalent Diffusion and Migration Laws for Electron Hopping Between Fixed Sites... 

According to the previous research on gas flow regularity, the migration law follows Darcy s law, that is. Laminar Elow—(Sun Peide, 1988). 

Saveant JM. Electron hopping between fixed sites equivalent diffusion and migration laws. J Electtoanal Chem 1986 201 211-213. 

Independent migration law analychem The law that each ion in a conductiometric titration contributes a definite amount to the total conductance, irrespective of the nature of the other ions in the electrolyte.. in-da pen-dont mT gra-shan, 16 Index of unsaturation org chem A numerical value that represents the number of rings or double bonds in a molecule a triple bond is considered to have the numerical value of 2. in.deks 3v lan.sach-a ra-shan ... 

Faraday s law (p. 496) galvanostat (p. 464) glass electrode (p. 477) hanging mercury drop electrode (p. 509) hydrodynamic voltammetry (p. 513) indicator electrode (p. 462) ionophore (p. 482) ion-selective electrode (p. 475) liquid-based ion-selective electrode (p. 482) liquid junction potential (p. 470) mass transport (p. 511) mediator (p. 500) membrane potential (p. 475) migration (p. 512) nonfaradaic current (p. 512)... 

Most of the surfaces that require repellent treatments are not smooth but contain capillaries into which a Hquid can migrate, even though the advancing contact angle of the Hquid on the surface is >0°. The law for the movement of Hquids into an idealized capillary is given by the equation ... 

Each ion has its own characteristic mobiUty. The total conductivity of the electrolyte is the sum of the conductivities of the positive and negative ions. This is known as Kohlrausch s Law of Independent Migration of Ions. 

Anions and cations exist in water. They migrate in an electric field and thus carry a current. Ohm s Law is applicable ... 

The factor B = D/RT is the mobility and contains the diffusion coefficient D, the gas constant R, and the absolute temperature T. The equation includes a diffusion and a migration term. Correspondingly Eq. (2-23) gives the first diffusion law for Zj = 0 and Ohm s Law for grad /i, = 0. For transfer across a phase boundary ... 

Of particular interest in the usage of polymers is the permeability of a gas, vapour or liquid through a film. Permeation is a three-part process and involves solution of small molecules in polymer, migration or diffusion through the polymer according to the concentration gradient, and emergence of the small particle at the outer surface. Hence permeability is the product of solubility and diffusion and it is possible to write, where the solubility obeys Henry s law,... 

Law enforcement agencies even use cyanoacrylates to obtain fingerprints on irregularly shaped objects and porous surfaces [39]. They first place the objeet to be tested in a tank with warmed ethyl cyanoaerylate. The ECA vapor migrates onto... 

For strong electrolytes the molar conductivity increases as the dilution is increased, but it appears to approach a limiting value known as the molar conductivity at infinite dilution. The quantity A00 can be determined by graphical extrapolation for dilute solutions of strong electrolytes. For weak electrolytes the extrapolation method cannot be used for the determination of Ax but it may be calculated from the molar conductivities at infinite dilution of the respective ions, use being made of the Law of Independent Migration of Ions . At infinite dilution the ions are independent of each other, and each contributes its part of the total conductivity, thus ... 

In the classical theory of conductivity of electrolyte solutions, independent ionic migration is assumed. However, in real solutions the mobilities Uj and molar conductivities Xj of the individual ions depend on the total solution concentration, a situation which, for instance, is reflected in Kohhausch s square-root law. The values of said quantities also depend on the identities of the other ions. All these observations point to an influence of ion-ion interaction on the migration of the ions in solution. 

The conductivity of solid salts and oxides was first investigated by M. Faraday in 1833. It was not yet known at that time that the nature of conduction in solid salts is different from that in metals. A number of fundamental studies were performed between 1914 and 1927 by Carl Tubandt in Germany and from 1923 onward by Abram Ioffe and co-workers in Russia. These studies demonstrated that a mechanism of ionic migration in the lattice over macroscopic distances is involved. It was shown that during current flow in such a solid electrolyte, electrochemical changes obeying Faraday s laws occur at the metal-electrolyte interface. 

In very thin (nanometer) films, where the potential gradient may exceed 10 V/m, another mechanism of ion migration is observed, which involves periodic jumps of ions between equilibrium positions, hi this case, the rate of migration is not proportional to the potential gradient but obeys the exponential law... 

The possibility of active transport of substances across membranes had first been pointed out in the middle of the nineteenth century by the physiologist Emil Heinrich du Bois-Reymond, a German of Swiss descent. The ability to accomplish active transport of ions and uncharged molecules in the direction of increasing electrochemical potentials is one of the most important features of cell membrane function. The law of independent ionic migration as a rule is violated in active transport. 

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