Uniformity correction

In the detector image P the ratio of the systematic effects is around 3-6 %. After the uniformity correction this ratio is now of 1-2 %. For the case of the detector image P which undergoes the deconvolution process directly, the ratio is very important around 25-45 %. The action of the correction itself with the deconvolution process reduces it to 5-6 %. 

Berne and Pecora s text [16] is sometimes incorrectly cited as asserting that eq 12 is uniformly correct for light-scattering spectra. The analysis in Berne and Pecora [16] correctly obtains eq 12. However, this analysis refers the special case of a system in which particle displacements are governed by the simple Langevin equation. In these s tems, particle displacements in successive moments are uncorrelated. However, in a viscoelastic system, the polymer solution has a memory particle displacements in successive moments are no longer uncorrelated. With respect to probes in polymer solutions, Berne and Pecora s analysis is only applicable at times mtich longer than any viscoelastic relaxation times. 

Figure 1.67 shows a schematic of a simple, but effective set-up for cryoscopy, the method for the measurement of the freezing point lowering. Cryoscopy is perhaps the easiest of the molar mass determinations. The main prerequisites are a good temperature control and uniformity, corrections for the common supercooling observed on crystallization, and the usual extrapolation to infinite dilution. The thermodynamic equations are derived in Sect. 2.2.5, together with the equations needed for the ebulliometry. 

FIGURE 27,9 Uniformity correction. Nonuniformilies in the field that remain after spatial linearity correction are corrected from the acqnisition of a high count reference flood image. In many cameras, the field uniformity degrades when the energy window is not centered on the photopeak. 

An elementary approach frequently used for estimating the increase in the average path length consists of applying a uniform correction factor to all macroscopic cross sections to account for the effective reduction in density due to the presence of the holes. On this basis, it is easy to show that the corrected diffusion length Lh (with holes) is related to the diffu-... 

Here, F(x, y) is the correction factor for a pixel at position x, y. In the simplest case, F(x, y) would be cos" ( ), but it could be the theoretical projected solid angle for a pixel at position x, y, or an empirical function that we can adjust to get the best fit - the most uniform corrected output. We can use any appropriate correction that is acceptable to the customer. 

Identification of a molecule known in the laboratory is usually unambiguous because of the uniqueness of the highly precise transition frequencies. However, before frequencies detected in the interstellar medium can be compared with laboratory frequencies they must be corrected for the Doppler effect (see Section 2.3.2) due to the motion of the clouds. In Sagittarius B2 the molecules are found to be travelling fairly uniformly with a velocity of... 

Solvents. Solvents in house paints serve several essential purposes. They keep the binder dispersed or dissolved and the pigments dispersed in an easy-to-use state. Solvents allow the paint to be appHed in the correct thickness and uniformity, and evaporate from the paint film after the paint is apphed. Solvent choice is limited mainly to a solvent that is compatible with the binder system and that has the desked evaporation rate and toxicity profile. The volatility or evaporation rate of a solvent determines to a large extent the open-time and dry-time properties of a paint (6). 

Guidelines for uniform density and dot gain limits have been estabHshed. These criteria ate the standards used to control the press. A densitometer is used to measure these standards and measurements ate made on sheets removed as the press is mnning. The operator then uses these measurements to guide press adjustments, primarily ink flows, to correct the printed result to standard (8). 

At least one of the preparer giUs wiU incorporate autoleveling. After the thickness of the feed sUvers is sensed, adjustments to the speed of the dehvery toUets ate automaticaUy made to correct deviations from the desired average. The aim is to achieve as high a degree of uniformity as possible in the shvets at the entry to the comb. 

The adhesive-coated veneers are then stacked in the correct order (thickness and number of pHes) to make the desired product and sent to a cold press. The pressure appHed by the cold press assures uniform adhesive distribution across the pHes and fliU adhesion later. From the cold press the assembly is moved to a hot press. The hot presses have up to 50 openings between steam heated plates. Depending on the thickness of the plywood being manufactured, one or more (up to three) layers of uncured plywood assembHes are loaded into each opening. The press is closed and pressure of 1.2—1.38 MPa (175—200 psi) and temperatures of 110—166°C are appHed for the period of time needed to cure the adhesive. The cured plywood panels are removed... 

Class B direct dyes have poor leveling power and exhaustion must be brought about by controlled salt addition. If these dyes are not taken up uniformly in the initial stages it is extremely difficult to correct the urdevelness. They are dyes that have medium—high affinity and poor diffusion. In their apphcation the cellulose is entered into a dyebath containing ordy dye. The salt is added gradually and portionwise as the temperature is increased and possibly the final additions made after the dyebath has come to the bod. 

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