Groove amplitude

The wavelength dependence in Eq. 14.13 can be used for experimental measurements of the surface and kinetic coefficients that constitute Bs. If an array of evenly spaced parallel grooves is introduced on a surface, the spacing dependence of the grooves amplitude-decay factor can be measured [6]. An analysis for flattening of an isotropic surface by bulk diffusion as in Fig. 3.7 is presented in Exercise 14.1. 

Groove amplitude In staggered groove designs, the distance the groove pattern oscillates about the central direction that the groove follows. It is... 

Anchor Pattern (Surface Profile)—the shape and amplitude of the profile of blast-cleaned or grooved steel, which influences the bond between metallic or paint films and the substrate. 

Due to the up-down symmetry usually assumed during relaxation of small amplitude modulations, we shall focus mostly on the upper half of the groove. 

Figure 8 Amplitude of the groove profile against t for Z, = 90a. The lifetime of the top terrace t can be determined from the local slope of the curve through interpolation.

Figure 8 shows the amplitude A (half the distance between top and bottom terrace, in units of layer spacing) of the surface profile as a function of t for a groove of wavelength L = 90a. The decay is slower than a simple exponential as in Mullins theory. From the function A t) one can estimate the lifetime of the top terrace t(t) using the formula,... 

Figure 9 Lifetime of the top terrace versus terrace width for grooves of different width and initial amplitude. The dashed line indicates a power law with an exponent 3. The solid line is a fit to Eq. (2.5). 

Figure 3.13 Variation of liquid penetration into a sinusoidal surface feature (Figure 3.12) with liquid contact angle [14]. Different curves are obtained for different groove dimensions peak-to-peak amplitude is indicated in nanometers next to each. (Reprinted with pramission. See Ref. 114]. 1993 American Chemical Society.)...

SRGs recorded with circularly polarized beams showed an even more interesting erasure behavior. The SRG can be erased by beams polarized parallel to the grooves and circularly polarized, as in the previous cases, but when erasing was tried with a beam polarized perpendicularly to the grating grooves an increase in diffraction efficiency and amplification of the surface modulation occurred (44% increase in the amplitude of the SRG, consistent with doubling of the diffraction efficiency). 

If there is clearance between a tube and its support, large amplitude tube motion can wear a groove in the tube at a support, in particular if the baffles are thin or harder than the tubes or there is a large baffle-to-tube clearance (baffle damage). 

Note For equal amplitudes Ak = Ao the time-dependent intensity l t) in (6.9) corresponds exactly to the spatial intensity distribution l x) of light diffracted by a grating with A grooves that are illuminated by a plane wave. One has to replace by the phase difference (j) between neighboring interfering partial waves, see (4.28) in Vol. 1, Sect. 4.1.3 and compare Fig. 4.21 in Vol. 1 and Fig. 6.9. 

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