Instrumental transfer width

The significance of instrument band width and modulation transfer function was discussed in connection with Equation (3) to characterize the roughness of nominally smooth surfaces. The mechanical (stylus) profilometer has a nonlinear response, and, strictly speaking, has no modulation transfer function because of this. The smallest spatial wavelength which the instrument can resolve, 4nin> given in terms of the stylus radius rand the amplitude aoi the structure as... 

The width and shape of the energy loss peaks in HREELS are usually completely determined by the relatively poor instrumental resolution. This means that no information can be obtained from HREELS about such interesting chemical physics questions as vibrational energy transfer, since the influence of the time scale and mechanism of vibrational excitations at surfaces on the lifetimes, and therefore the line widths and shapes, is swamped. (Adsorbates on surfaces have intrinsic vibra-... 

Although the power spectral density contains information about the surface roughness, it is often convenient to describe the surface roughness in terms of a single number or quantity. The most commonly used surface-finish parameter is the root-mean-squared (rms) roughness a. The rms roughness is given in terms of the instrument s band width and modulation transfer function, M(p, q) as... 

Different values of will result if the integral limits (i.e., band width) or modulation transfer function in the integral change. All surface characterization instruments have a band width and modulation transfer function. If rms roughness values for the same surface obtained using different instruments are to be compared, optimally the band widths and modulation transfer functions would be the same they should at least be known. In the case of isotropic surface structure, the spatial frequencies p and q are identical, and a single spatial frequency (/>) or spatial wavelength d= /p) is used to describe the lateral dimension of structure of the sample. 

Infrared spectra of the unfilled and filled copolymers were measured using a Perkin-Elmer model 1700 FTIR spectrometer. The 13C CP/MAS NMR measurements were conducted on a Bruker 300 instrument operating at 75.51 MHz. The samples were rotated with a spectra width of 40.0 Hz, the CP time was 5 ms. l3C lI distortionless enhancement by polarization transfer (DEPT) technique was applied for analysis of monomers. The process was performed at 75.51 MHz, rotated with a spectral width of 0.75 Hz and a CP time of 15 ms. Atomic force microscopy measurements were carried out using a Nanoscope Ilia controlled Dimension 3000 AFM (Digital Instrument, Santa Barbara, CA). 

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