Scan velocity

Displacement of 15-pm polystyrene beads as a function of either constant scanning velocity or constant laser power. 

Fig. 7.3.5 Plasma scan from a healthy individual (a) and from an individual with porphyria var-iegata (b). Scanning velocity 200 nm/min, range 500-700. Emission maximum at 627 nm indicated by an arrow...

FT-IR spectrometers have interferometers with scanning velocities enabling the collection of tens of spectra per second at a spectral resolution of 8 cnr1 or less. With faster data collection capabilities, FT-IR spectroscopy can be used to monitor and observe dynamic gas-phase processes. To observe such a process, interferograms are sequentially collected and stored in the memory of the system. The interferograms are then processed at the end of the data acquisition. The result of this operation is a three-dimensional data cube where each vertical slice of the cube is the spectrum for a time slice in the experiment equal to the interferogram acquisition time. 

Sensitivity is improved in GB-A-2094548. The length of the detector element or the magnitudes of the bias and scan velocity are selected so that the time taken to scan the detector element from one end to a read-out region is greater than the lifetime of the photocarriers generated in the element. 

The phenomenon has been studied by Gao and Sonin [16] and it has been shown that the cross-sectional area and apparent contact angle of a printed bead is a function of the substrate temperature and the print-scan velocity. A quantitative analysis of jet-printed phase change materials was reported by Schiaffino and Sonin [17] for isothermal conditions. The results showed that the contact angles for the printed drops could be varied as a function of the substrate temperature. By adjusting the substrate temperature and the scanning speed, the feature size and print quality can be adjusted without having to modify the substrate surface energy. 

Electrical current via mechanical contact Electrical tunnelling current Scan velocity Maugis parameter Thermal conductivity... 

Once all imaging parameters are set, data can be acquired and captured. It is important to note that the data may depend on the actual settings (force, scan velocity, feedback loop quality, etc.) therefore, one should note these parameters independently. The data displayed on the screen is typically planefitted to be readable (in case the sample plane does not coincide with the horizontal x, y = 0, 0 plane of the scanner, the image would appear tilted and flat surfaces would appear in saturated colors compare also Sect. 2.2.7). A line-by-line planefit is most often utilized. Here, the data of each captured scan line is normalized by subtracting a first order polynomial fit from the particular line. The captured data, however, should be captured without planefit in order to facilitate meaningful analysis at a later stage (Sect. 2.2.7). 

Accordingly rapid changes in optical frequencies are transformed to lower frequencies, where they can be measured with the normal detector systems. For a wavelength of 400 nm or a frequency of 25000 s-1 and a scanning velocity of 0.08 cm/s the frequency becomes 2 kHz. 

FIGURE 18.3 Schematic of the variation of T with scanning velocity and beam shape [18]. 

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