Displacement effect

The term basic used with defines the hydroxyl ion s displacement of H2O in the primary coordination sphere of Cr(III). This displacement effectively... 

A chromatographic separation can be developed in three ways, by displacement development, by frontal analysis, and by elution development, the last being almost universally used in all analytical chromatography. Nevertheless, for the sake of completeness, and because in preparative chromatography (under certain conditions of mass overload) displacement effects occur to varying extents, all three development processes will be described. 

Dielectric loss The dielectric loss factor represents energy that is lost to the insulator as a result of its being subjected to alternating current (AC) fields. The effect is caused by the rotation of dipoles in the plastic structure and by the displacement effects in the plastic chain caused by the electrical fields. The frictional effects cause energy absorption and the effect is analogous to the mechanical hysteresis effects except that the motion of the material is field induced instead of mechanically induced. 

The problem of the separation of samples containing components of widely different polarities is difficult because of general elution. This can be solved by use of gradient elution. As has been observed, in TLC separation of plant extracts, gradient elution markedly improves the separation of spots owing to stronger displacement effects... 

Gerstner, J. A. and Cramer, S. M., Cation-exchange displacement chromatography of proteins with protamine displacers effect of salt-induced gradients, Biotechnol. Prog., 8, 540, 1992. 

Such displacement effects, although often very pronounced, have not yet been studied systematically. They will be the subject of the present paper. We will discuss the adsorption of polymer from a mixture of two solvents and we will see that in some cases drastic effects occur as a function of the mixture composition. Also, we explore some consequences and practical applications of displacement. It turns out that displacement studies not only increase our insight on the role of the solvent in polymer adsorption but can also be used to determine the segmental adsorption energy. So far, experimental data for this quantity were very scarce. Some illustrative experiments will be discussed briefly. 

Observation of displacement effects resulting from O-substitution, and use of standards, led to the assignment of the chemical structure of the polysaccharide of Neisseria meningitidis serogroup 29e, which consists of 2-acetamido-2-deoxy-D-galactosyl and partly acetylated 3-deoxy-D-manno-octulosylonic acid (KDO) residues.166 The 13C-n.m.r. spectrum of the O-deacetylated polymer (see Fig. 36,B) contained 15 signals out of the possible 16 expected from an alternating structure. Comparison of these resonances with those of the anomers of 2-aceta-... 

Use of zwitterions is an alternative approach that provides more effective mobilization of protein zones across a wide pH gradient.83 For example, cathodic mobilization with a low-pi zwitterion enables efficient mobilization of proteins with pis ranging from 4.65 to 9.60. The proposed mechanism for zwitterion mobilization couples a pH shift at the proximal end of the tube with a displacement effect at the distal end as the zwitterion forms an expanding zone within the gradient at its pi. Effective zwitterion mobilization depends on the selection of the appropriate mobilization reagent. 

The importance of the strength of tt complex adsorption on the reaction rate through the operation of displacement effects is further demonstrated by naphthalene randomization reactions. Naphthalene exchanges very slowly with deuterium oxide. That this is due to the displacement of water by normal naphthalene and not due to a toxic side reaction, such as polymerization, is shown in randomization experiments with mono a-deuterated naphthalene. Randomization is completed within 24 hours at 120°, whereas no significant deuteration occurs under the same reaction conditions with water. This result furnishes additional proof for the dissociative exchange mechanism. 

Keywords Hydrogen-bonded ferroelectrics Order/disorder-displacive effects ... 

In contrast, in Figure 10.3c, the minor component is less retained than the major one. The component present in large excess in the sample displaces the other component out of the stationary phase, and the displacement effect of the first component, at the front of the second component band is observed. The first component elutes from the column sooner as if it were injected separately on the column. 

On the assumption of a somewhat mobile double layer, electrostatic attraction between particles may occur, due to this displacement effect, even if the total net charge be not zero, i.e. coagulation may take place before the isoelectric point is reached. The data of Zsigmondy on gold particles, and of Powis Zeit. Phys. Ohem. Lxxxix 186, 1915) on oil particles, have indeed shown that the optimum point for precipitation is not actually at the isoelectric point, although in the case of gold, practically complete discharge of the double layer had to take place before coalescence. 

Therefore, it was by means of displacements in Space that the existence of the Land of the Fourth Dimension was first revealed to me. And, once again, I do not really know how to explain these displacements by just building upon current language, for that is one only constructed in three dimensions. I am, therefore, and despite my misgivings, forced to resort to crude imagery I must revert to ancient means of expression, to those once believed exclusive to Alchemy. I will employ these [alchemical] terms in order to describe a fact which is, nevertheless, quite simple. It will, nonetheless, not fail to amaze the reader, especially one scarcely familiar with the UNITY of a point of view which characterizes the Fourth Dimension. In same way that one resorts today to atomic theory in order to provide an adequate image of chemical combinations, so too must I resort to an analogous [alchemical] hypothesis in order to explain, however crudely, the nature of displacements effected within the Land of the Fourth Dimension. Here follows this imperfect [alchemical] explanation. 

Some of the basic experiments with UPD have been carried out with Ag onto Au (hkl).94 This is because the radii of Ag and Au atoms are almost the same, so that the interpretation does nothave to involve a steric displacement effect. Figure 7.143 shows the underpotential deposition of Ag on Au (100). The A and D marks on the figure denote a number of underpotential processes. Using STM to study this system indicates that at AE> 650 mV, a stable Ag surface is formed with normal interatomic distance. Between 200 < AE < 550 mV, stable domains exist, but now (see Fig. 7.144) they are expanded in respect to their interatomic distance and in comparison with those formed at AE > 650. 

Figure 3.4 (a) Disturbance stream function as a function of x caused by circulatory and displacement effects at y = 1.92, when the freestream vortex is at Xc = 5 // = 6 and c = 0.1545 (b) Pressure gradient at the same height for the case of (a) (c) Pressure gradient as a function of time at x = 5 and same height when the vortex is started from Xc = 1 and (d) variation of Falkner-Skan parameter m with x for the indicated time instants. 

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