Experimental windows

Lines in Figure 30.12 were drawn with parameters obtained when fitting data with Equation 30.3. It is fairly obvious that, outside the experimental window, data would not necessarily conform to such a simple model, which in addition cannot meet the inflection at 100% strain. All results were nevertheless fitted with the model essentially because correlation coefficient were excellent, thus meaning that the essential features of G versus strain dependence are conveniently captured through fit parameters. Furthermore any data can be recalculated with confidence within the experimental strain range with an implicit correction for experimental scatter. Results are given in Table 30.1 note that 1/A values are given instead of A. 

As shown by the dashed curves in Figure 30.16, fitting 1.0 Hz results with Equation 30.4 yields plateau values, which likely have no physical meaning, with respect to 0.5 Hz data. However, fit parameters of this equation (as given in Table 30.2) allow the slope to be calculated at any strain within the experimental window. It follows that the slope at a given strain, for instance 200%,... 

The electronic spectrum reveals at least two states that should be observed, provided the experimental window is enlarged beyond the 2000-6000 A region. 

Excited states of hydrocarbon molecules often undergo nondissociative transformation, although dissociative transformation is not unknown. In the liquid phase, these excited states are either formed directly or, more often, indirectly by electron-ion or ion-ion recombination. In the latter case, the ultimate fate (e.g., light emission) will be delayed, which offers an experimental window for discrimination. A similar situation exists in liquid argon (and probably other liquefied rare gases), where it has been estimated that -20% of the excitons obtained under high-energy irradiation are formed directly and the rest by recombination (Kubota et al., 1976). 

Recently, modem ultrafast spectroscopic methods have opened a new experimental window on the molecular dynamics of water, examining the OH-stretch dynamics for the experimentally convenient aqueous system of HOD diluted in D2O using ultrafast infrared (IR) [1-6], IR-Raman [7], or photon echo [8] spectroscopy. 

Figure 1. Diagram of the intensity / (W/cm2) vs. duration of laser pulse tp(s) with various regimes of interaction of the laser pulse with a condensed medium being indicated very qualitatively. At high-intensity and high-energy fluence 4> = rpI optical damage of the medium occurs. Coherent interaction takes place for subpicosecond pulses with tp < Ti, tivr. For low-eneigy fluence (4> < 0.001 J/cm2) the efficiency of laser excitation of molecules is very low (linear interaction range). As a result the experimental window for coherent control occupies the restricted area of this approximate diagram with flexible border lines.

Fig. 16 Sketch of the hypothetic variation of the miscibility gap with increasing chemical charge density (experimental window indicated by rectangle)...

The use of this time-temperature equivalence allows one to obtain "master curves" at a reference temperature, which enlarges considerably the experimental window. For glass-forming materials such as polystyrene, polymethylmetacrylate, polycarbonate, polymerists describe the shift factor aj in terms of the WLF equation ... 

The shear damping function obtained from transient experiments remains unchanged whatever the shear rate is in the experimental window, so that one may assume that it is not shear-rate dependent. More surprising is the large discrepancy between the results between the two methods, wherein the step... 

WW model correspond to parameters which are not physically reasonable and stable as regards to variations in the experimental window (see Table 4). 

The HH model fits correctly experimental anisotropies in all the temperature range explored (—55 °C/80 °C). But the long time loss term rapidly faUs far off the experimental window when the temperature is decreased, and its characteristic time X2 could be determined with a reasonable precision only above 40 °C. In the range 40 °C/80 °C, the ratio does not seem to vary significantly, and remains rather high ( 30). If one accepts the separation of the OACF into a one-dimension... 

Table 5. Best fit parameters obtained when different models are fitted to the anisotropy of PBAPB at 62.7 C using different experimental windows 1 0 ns — 55ns 2 1.3ns — 55ns 3 3.2ns — 55 ns 4 0 ns — 37 ns 5 0 ns — 17 ns...

The Effect of Polymer Heterogeneity on the Enthalpy. The kinetics of the isotropic-smectic phase transition were studied for two of the polymers HPX-C9 and HPX-C11, and in Figure 8 a summary of the calorimetric data for the former is presented. The behaviour of the HPX-C11 polymer was similar. Two processes are in fact revealed by these data (a) at high temperatures (7 471.9 K) the two processes have approximately the same induction time and rate and are therefore not resolved, (b) at intermediate temperatures (468.9heat evolved in the slower process is 30-50% of that evolved in the more rapid process. There is a tendency for an increase in Ah0 for the slow process with increasing temperature for HPX-C9, Ah0 was equal to 13 kJ/kg at 468.9 K and 20kJ/kg at 470.9 K. The same trend was observed for HPX-C11. (c) at low temperatures (TS467.9 K), the slower process was much retarded and not observed within the experimental window. 

It is a common practice to use the thickness of the deposited film divided by the deposition time to represent the deposition rate. This is in principle incorrect. The reaction rate in the heterogeneous kinetic rate theory should be expressed in terms of moles/sec cm2 or in similar units. Only when it is verified that there are no density and/or compositional changes in the experimental window of interest can one exchange the reaction rate in moles/sec cm2 by the deposition rate in nm/sec. The determination of the deposition rate, however, needs some further clarification. 

By changing the diffusion time it is possible to find an experimental window that allows for calculations of structure-related diffusion. During shorter diffusion times, the effect of dimensionality and cormectivity is small and it is possible to perform calculations in two dimensions without losing too much information. However, during long diffusion times, the effect of dimensionality and connectivity increases and a three-dimensional description of the microstructure is needed. 

The polarized emission spectra and the apparatus response (recorded at emission wavelength) were sampled with a 0.12 ns channel width by the single-photon counting technique. Thanks to the stability of the pulses, the short-time limit of the experimental window is about 0.1 ns. The upper limit, imposed by the repetition rate of the pulses and the lifetime of the dye, is 2 ns. 

The experimental window of the batch experiments is shown in Table 2. 

Contrary to the expectations the atomization pressure has no effect on the size of the primary particles within the experimental window. The relatively low bulk density and the appearance of the punctured particles suggest that the particles are hollow. 

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