Cooling versus slowing

Figure 28. Fluorescence decays and double exponential fits corresponding to the 20S cm"1 bands in the (from top to bottom) vlb = 1237, 1241, 1246,1249, and 1332 cm-1 spectra of jet-cooled c-stilbene. Given in the figure are the best-fit parameters for both the fast and slow lifetimes, and the ratio (F/S) of preexponential factors of fast versus slow fluorescence. All decays were obtained with R = 3.2 A. 

In the region where magnetic effects must be considered, a resistivity study on CeHj+ c (0 < X < 0.01) by Vajda et al. (1990) shows that the appearance of low-temperature anomalies related to magnetic transitions depends on whether the system is cooled slowly enough for ordering to occur. Both heavy-fermion and Kondo-lattice behaviors are inferred from the low-temperature results (T<20K) and a close competition between magnetic order and the Kondo effect is revealed by data from quenched versus slow-cooled samples. 

Single crystals of RbsNbgOFig can be grown successfully by dissolving the prepared compound in a 20-30% HF solution at increased temperature and subsequent slow cooling of the solution down to room temperature. The solubility of RbgNbjOFjg in 20% HF solution versus the temperature of the solution is given in Fig. 7. 

Figure 5 Resistivity of Nd2Cu04 xFx versus temperature, (a) x 0 sample made in air at 900°C. (b) x=0 sample reduced at 890°C under 60 ppm 02N2 (c) x 0.1 fluorinated sample after initial firing in dry air at 900°C. (d) x=0.18 sample reduced 890°C in flowing N2 containing 60 ppm 02 and cooled at 300°C/hr (slow cooling replaces annealing step).

Fig. 10. Modulus versus draw ratio for a variety of quenched (open symbols) and slow-cooled (solid symbols) LPE samples drawn at 75 °C...

Figure 3.7 The critical temperature, Tc, is determined as the maximum point of the plot (phase diagram) of Tp versus (p2, also called the cloud point curve or the precipitation curve. Tp is the temperature at which detectable turbidity can first be observed visually upon slow cooling (1-2°C per 10 min).

FIGURE 4.7 Effect of cooling rate on and the glassy volume. Shown is free volume versus temperature for (a) slow cooling and (b) faster cooling. Solid lines represent equilibrium, from a stepwise reduction of temperature. Dashed lines depict schematically the trend of experimental behavior. (Adapted from Vleeshouwers [1993].)... 

Figure 2.11 Volume versus temperature relationship for the cooling process of a glassy polymer a slow densification occurs at service temperature, Tg, below Tg.

The only down sides of cooled CCD cameras have been their relatively slow read-out rate (typically 0.5-1.0 million pixels/sec) and their relatively high cost. For most cell biological applications, the slow read-out rate is not a consideration. For example, in most immunofluorescence applications the camera exposure time is longer than the camera read-out time (typical exposure times of 1-10 sec versus read-out times of 1-2 sec). Cooled CCD camera read-out rates have been entirely adequate for our time-resolved, two-component, three-dimensional recordings of the short mitoses of Drosophila early embryos (Paddy et ai, 1996). However, researchers following very rapid cell phenomena in situ. 

CPE-2. As mentioned above, dynamic mechanical properties of thermotropic LC polyesters become reproducable and stable after heating to the temperature of the high-temperature tan 8 maximum and slow cooling back to room temperature. Therefore, the plots of E and tan 8 versus temperature considered below were obtained with CPE-2 fibers heated to 200°C and cooled at 5 °C/min. 

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