Contrast measurements

Sensitive to lighting conditions degradation in storage contrast measurement from film subject to significant errors... 

We have developed another bench for the measurement of the contrast value. Contrast measurement have been carried out on the MMA fabricated by Texas Instrument, in order to establish the test procedure (Zamkotsian et al., 2002a Zamkotsian et al., 2003). We can address several parameters in our experiment, as the size of the source, its location with respect to the micro-elements, the wavelength, and the input and output pupil size. In order to measure the contrast, the micro-mirrors are tilted between the ON position (towards the spectrograph) or the OFF position (towards a light trap). Contrast exceeding 400 has been measured for a 10° ON/OFF angle. Effects of object position on the micro-mirrors and contrast reduction when the exit pupil size is increasing have also been revealed. 

Figure 4. The fringe contrasts measure the resemblance (cross-correlation) of the two mixed fields, (right).

Figure 18. ISTROG Interferometer. The high improvement on the accuracy of contrast measurements with such devices mainly results from the efficient spatial filtering and the spatial stability of the recombining assembly.

Sensitivity and Contrast Measurements. Imagewise exposure of films of the various copolymers containing from 5-10% triphenylsulfonium hexafluoroantimo-nate to UV light at 254 nm resulted in the crosslinking of the exposed areas as shown in Figure 4. 

By contrast, measurement of pATR = 4.7 for the Fe(CO)3-cooordinated cyclo-hexadienyl cation 44 (Scheme 26) indicates a 107-fold more favorable equilibrium constant for carbocation formation than for the uncoordinated cation.197 However, a more dramatic effect of coordination is to render nucleophilic reaction with water more favorable than loss of a proton. A pXa = 9 can be estimated by computing the energy differences between coordinated and uncoordinated benzene and coordinated cyclohexadiene. This compares with the value of —24.5 for the uncoordinated cyclohexadienyl cation. The large difference must reflect the unfavorable effect of Fe(CO)3 coordination on benzene, an effect analogous to that found by Mayr for Fe (CO)3 coordination on the tropylium ion.196 As expected, both the coordinated cyclohexadienyl and tropylium ions are highly stereoselective toward exo attack by water. 

Determination of several atmospheric oxidant species is critical to understanding gaseous and aqueous processes leading to acidic deposition. Hydrogen peroxide has a high Henry s Law solubility and must be measured in gaseous and aqueous atmospheric samples to better understand wet deposition processes. In contrast, measurements of ozone and peroxyacyl nitrates (PANs) (and probably alkyl hydroperoxides and peracids) usually need to be made only in the gas phase due to their low aqueous solubility (14). 

Just as the reflectance and transmittance measurements can be used in one database, contrast measurements can also be applied to a single database (or even combined with reflectance and transmission measurements for the calibration of the database). In this case the two measurements that would be combined are the over white and over black measurements. Typically this technique is applied to coatings and printing inks on paper or screen inks on textiles (white and black cloth). 

U-series nuclide activities can be measured directly by detection of their emitted nuclear particles, e.g., alpha particle counting by solid-state detectors (Ivanovich and Harmon, 1992). In contrast, measurements by mass-spectrometry do not require waiting for Nature to take its course. Atoms of the sample are ionized and accelerated so that charged particles of the nuclides themselves can be measured by Faraday cups or electron multipliers (see Goldstein and Stirling, 2003). Mass-spectrometry is hence a more rapid technique. Typically mass-spectrometry measurements take tens of minutes to hours, while counting methods require days to weeks. 

In contrast measurements of carbon Is electron binding energies in several hydrocarbons yielded a rather narrow range of chemical shifts. For instance, one cannot make a distinction between the carbon atoms of neopentane and those of benzene because their Is binding energies are virtually the same (290.4 eV). Ethane... 

VESUVIO measurements on Nhi) [Karlsson 1999] and polystyrene [Karls-son 2003 (b)], also show ratios of 77 to heavier atom cross sections which are independent of angle. In contrast measurements on Formvar [Chatzidimitriou-Dreismann 2003 (a)], shown in Fig. 6, give a marked fall off in the H to heavy atom cross section ratio as the scattering angle and hence q is increased. Measurements on NbH [Karlsson 1999] have an even stronger angular dependence. Thus no single 7 value can explain anomalies observed in different samples. 

The nondestructive nature of MRI makes it ideal to study the microstructure at the various stages of ceramics processing. For example, Tj contrast measurement is used to discriminate between crystalline, amorphous, and highly plasticized binder materials to... 

In the absence of molybdenum, the blank dehydrated zeolites showed no CO hydrogenation activity even up to 400°C. In contrast, measurable quantities of aliphatic hydrocarbons were detected over the molybdenum-zeolite catalysts at 300°C and above. Figs. 1-2 show the time dependence of CO conversion over MOii g HY and Mo g CsY at 300°C. The conversion and product distribution were dependent on the reaction conditions, a typical set of results is illustrated in Table 1. The molybdenum-zeolites prepared by adsorption and decomposition of Mo(C0)g resembled closely the alumina-supported molybdenum catalysts prepared by decomposing Mo(C0)g on alumina (ref. 13). The results obtained presently could not match the figures reported by Brenner et aK (ref. 8), but this could be due to the significant differences in the reaction conditions used by the above authors. However, a comparison with the silica-molybdena catalyst (prepared by impregnation of ammonium molybdate) clearly indicates that the molybdenum-zeolites were more active on per molybdenum basis. The improved activity is due to the presence of zerovalent molybdenum (for LaY and HY, residual zerovalent molybdenum were responsible for the activity). 

In contrast to the Hake and Stewart (1977) study, Altmaim et al. (1990) found a statistically significant (p<0.05) increase in latency of pattern reversal visual-evoked potentials in 10 male volunteers exposed to tetrachloroethylene at 50 ppm for 4 hours/day for 4 days, relative to 12 subjects exposed at 10 ppm. No effects on brainstem auditory-evoked potentials were noted. Tests of visual contrast measured in a few individuals showed a tendency for loss of contrast in the low and intermediate spatial frequencies at 50 ppm. In this study, measurements were also completed the day before exposure so each individual served as his own control. The 10-ppm group was considered the control group, and this concentration was used because it is well above the odor threshold of tetrachloroethylene so that there was at least an attempt to blind the subjects to the exposure concentrations. Blood tetrachloroethylene concentrations were measured before, in the middle, and at the end of each day s exposure, and an association between the effect on pattern reversal visual-evoked potentials and blood tetrachloroethylene concentrations was observed (p<0.03). The lack of effect on flash visual-evoked potentials in the Hake and Stewart (1977) study at concentrations up to 100 ppm compared to an effect on pattern reversal visual-evoked potentials at 50 ppm in the Altmann et al. (1990) study may reflect the greater inter- and intrasubject variability of waveforms for flash visual-evoked potentials (Otto et al. 1988). 

The pressures calculated using the above approaches generally use the linear (Airy) theory and expect the pore pressure response to be in phase with the surface waves. This is in agreement with what has been measured for sandy bottoms. In contrast, measurements made by Hirst and Richards (1978) showed that bottom pressures can be much larger than predicted by linear theory for soft clayey bottoms. In Sections 9.6.3.1 and 9.6.S.2 the case of a rigid seabed (i.e., sandy bottom) will be considered first followed by the case of a deformable seabed (i.e., soft clayey bottom). 

The past few years have seen a maJcM- advance in quantitative measurements on noble gas atom reactions. Such studies divide into two major groups, dqxnding on whether the total rate of removal of the excited noble gas atom or the rate of a specific reaction channel is being measure. Up till now, the form technique has given the more reliable results in that it is possible to work under pseudo-first-order conditions with an excess of quenching agent, so that only relative excited atom concentrations are required. In contrast, measurement of the rates of specific channels requires in general the absolute rate of appearance of the [ oducts and the absolute concentration of excited atoms, both of which measurements are subject to systematic errors. 

Die = differential interference contrast. Measurement conditions, see Figure 24.4. (Adapted with permission from [15]. Copyright 2012, American Chemical Society.)... 

Needless to say, the embedded impedance for a single element is by far the simplest of the three types of impedance to implement. You only need a single connector at one element in the middle of the array, while all the others are terminated by resistors that can be either soldered in place or simply printed. In contrast, measurements of the scan impedance may require a connector or equivalent at each element, and, most importantly, we must be able to apply voltages at each terminal and be able to control these voltages in phase as well as amplitude. 

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