Focusing effect

As in conventional IEF, the high resolving power of CIEF depends upon the focusing effect of the technique. At steady state, the ampholytes form a stable pH gradient within which proteins become focused at the positions where their net charges are zero, i.e., where pH = pi. Diffusion of a protein toward the anode (positive electrode) will result in the acquisition of positive charge, and the... 

Douglas DJ, French JB (1992) Collisional focusing effects in radio frequency quadropoles. J Am Soc Mass Spectrom 3 398-407... 

EXAFS data at the Co and Al K edges for Co Al - Cl LDHs were consistent with an ordered array of cations for n = 2,3 and 4. In each case the Al has a second coordination shell of 6 Co ions and the Co has a second shell of 6/n Al and (6-6/ ) Co next nearest neighbors [46]. The peaks arising from the focusing effect are still observed in the Co K edge EXAFS of the material showing that the cobalt cations in the layers remain ahgned. 

In the structure A, the transverse profile of the initial pulse varies behind the junction due to the self-focusing effect. In the nonlinear waveguide of the structure, a fraction of an initial pulse power is emitted from the guiding region (Fig. 19). 

Behind the junction, power of the field propagating within the core increases due to the self-focusing effect, while the pulse duration at the waveguide axis decreases. In the quasi-static approximation, this effect does not depend on the initial pulse duration. Total losses vary with power at the pulse peak similar to the case of stationary wave propagation in the structure A, i.e. they increase with the power (Fig.21, compare with Fig.l 1). 

It is seen that longitudinal dependences of the variation in the pulse duration plotted for 2 of the same modulus but different signs are approximately symmetrical with respect to the curve obtained in the quasistatic approximation. Hence, at normal GVD, the pulse duration is shorter than the initial one as a result of the self-focusing effect until, owing to GVD, this duration continuously increases to its initial value (denoted by asterisks) and then exceeds it. The size of the region within which the pulse compression is observed at decreases with increasing 2 - In turn,... 

The relative decrease Atq of the pulse duration depends approximately linearly on when 2 < 0 (Fig.31). For 2 > 0, at high powers (e.g. ppeak > 2 in Fig.31), the relative increase of the pulse duration is also almost linear. In this case, such propagation is possible when the pulse duration virtually does not depend on the power of the initial beam. This might result from a balance between the self-focusing effect which decreases the pulse duration (dashed line in Fig.31) and the normal GVD effect which broadens the pulse. 

Ocean. The former is estimated to have a surface area the size of Texas. The focusing effect of the Kuroshio Current on the density of plastics collected in plankton net tows is shown in Figure 28.35. In some locations, particle densities are greater than that of the local zooplankton. High concentrations have also been reported on the seabed near industrialized areas such as the Mediterranean and the North Seas. In 2000, the volume of litter estimated to be residing on the seabed of the North Sea was 600,000 m. ... 

Many modern spectroscopes employ the diffraction grating instead of the prism. In the concave grating spectroscope, developed by Rowland, the collimating lens and telescope or camera objective are unnecessary because of the focusing effect of the grating itself. See Fig, 2,... 

Figure 14.9 Top view of the sectors, or the hills and valleys, in a sector-focused cyclotrons. In (a) the concept of strong vertical focusing at the transition regions, edges, of the sectors is shown for straight sectors. A larger focusing effect is obtained hy spiraling the sectors as shown in (b). Note that the particles travel counterclockwise in this figure.

Figure 14.12 Net focusing effect on a diverging charged particle beam from the combination of a converging and diverging pair of magnetic quadrupole lenses. The key feature of the doublet is that the particles move along paths that are closer to the optical axis in the defocusing element of the pair. (From Harvey, 1964.)...

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