Surface charge effect

Survey capability with ppm detection limits, not affected by surface charging effects complete elemental coverage survey microanalysis of contaminated areas, chemical failure analysis... 

In above sections the main attention has been paid to adsorption-caused change in electrophysical characteristics of semiconductor adsorbent caused by surface charging effects. However, as it was mentioned in section 1.6, the change in electrophysical characteristics of such adsorbents can be caused by other mechanisms, e.g. by direct interaction of absorbate with the surface defects provided (as in the case of oxide adsorbents) by superstoichiometric atoms of metals and oxygen... 

Besides the experimental data mentioned above, the kinetic dependencies of oxide adsorption of various metals are also of great interest. These dependencies have been evaluated on the basis of the variation of sensitive element (film of zinc oxide) conductivity using tiie sensor method. The deduced dependencies and their experimental verification proved that for small occupation of the film surface by metal atoms the Boltzman statistics can be used to perform calculations concerning conductivity electrons of semiconductors, disregarding the surface charge effect as well as the effect of aggregation of adsorbed atoms in theoretical description of adsorption and ionization of adsorbed metal atoms. Considering the equilibrium vapour method, the study [32] shows that... 

Seelig, A., Allegrini, P. R. and Seelig, J. (1988). Partitioning of local anesthetics into membranes surface charge effects monitored by the phospholipid head-group, Biochim. Biophys. Acta, 939, 267-276. 

The exponential term can be thought of as a surface activity coefficient (Dzombak and Morel, 1990) that corrects the apparent acidity constants for surface charge effects. 

Hegde S, Babu SV. Study of surface charge effects on oxide and nitride planarization using alumina/ceria mixed abrasive slurries. Electrochem Solid State Lett 2004 7(12) G316-G318. 

The influence of metal oxide derived membrane material with regard to permeability and solute rejection was first reported by Vernon Ballou et al. [42,43] in the early 70s concerning mesoporous glass membranes. Filtration of sodium chloride and urea was studied with porous glass membranes in close-end capillary form, to determine the effect of pressure, temperature and concentration variations on lifetime rejection and flux characteristics. In this work experiments were considered as hyperfiltration (reverse osmosis) due to the high pressure applied to the membranes, 40 to 120 atm. In fact, results reproduced in Table 12.3 show that these membranes do not behave as h)qjerfiltra-tion membranes but as membranes with intermediate performances between ultra- and nanofiltration in which surface charge effect of metal oxide material plays an important role in solute rejection. 

Newcombe G. (1994). Activated carbon and soluble humic substances adsorption, desorption, and surface charge effects. J. Colloid Interface Sci., 164, 452-62. 

Goloub, T.P. et al.. Adsorption of cationic surfactants on silica. Surface charge effects, Langmuir, 12, 3188, 1996. 

S. Alila, S. Boufi, and M.N. Belgacem, "Adsorption of a Cationic Surfactant onto Cellulosic Fibers I. Surface Charge Effects", Langmuir, Vol. 21, pp. 8106-8113,2005. 

Alloways, B.J., 1995. Heavy Metals in Soils, Blackie Academic Professional, London, UK. Appel, C., Ma, L., 2002. Concentration, pH, and surface charge effects on cadmium and lead sorption in three tropical soils. J. Envir. Qual. 31, 581-589. 

Surface Charge Effects on Charge Transfer Reaction Rates... 

It is interesting to note that, historically, protein played the favorite role in attempts to understand the functional dynamics of cellular metabolism and membrane physiology. Once the functional importance of the lipid component of membranes was recognized, most of the initial experimental effort was aimed at hydrophobic effects. However, it is now recognized that surface charge effects associated with membrane phospholipids have been shown to profoundly affect enzymatic activity and influence the action of various hormones, vitamins, and drugs. 

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