Thick vs. Thin Samples

In many problems of trace analysis, the scatter mass limits the performance of the X-ray energy spectrometer in thick samples. Since the backseat ter 

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FIGURE 2. The absorbance at 508 nm vs. time for four thin films of the polyurethane synthesized by equation 3. Only the sample exposed to both light and air degraded. The absorbance at 508 nm is characteristic of the metal-metal bond. The differences in absorbance at time = 0 are due to different thicknesses of the various samples. 

Fig. 21. a Local d75 volume fraction (1—4>) as a function of depth z ( points and the thick solid line), determined for the h86/d75 blend monolayer with 30%h86 following 46 h of annealing at 86 °C [145]. The thin solid line corresponds to the non-annealed sample with identical bulk composition. The hatched area marks the h86 surface excess z. The inset marks the h86 bulk compositions <)> for which z was determined. Solid curve in the inset denotes binodal, determined previously [91] and described by %=(0.547/T-8X10"5)(l-0.217c])). b Segregation isotherm data (corresponding to T=72 °C (O) and T=86 °C ( )) plotted as normalized surface excess z w - )] vs normalized bulk volume fraction Solid lines are generated by Eq. 44 to fit the data. Dashed horizontal lines are normalized surface excess values for the bulk phase enriched at the surface to the compositions < >s such that (c))2-())s)/(<[)2—c])1)= 10%, 5%, and 1%, respectively... 

Figure 8.7 Change in transmittance (upper part) and deflection angle variation (lower part) of a lithiated nickel oxide thin-film electrode following a cathodic insertion run at constant voltage (V= 1.1 vs Li). The vertical bar corresponds to a stress variation of 1 GPa. Sample thickness 2000A. Reference and counter-electrodes Li metal foils. Electrolyte iM LiC104-PC. From [26] by permission of Elsevier Science Publishers, Amsterdam.

The mechanical properties of the layered composites were tested on a custom-made thin film tensile strength tester (McAllister Inc.) recording the displacement and applied force by using pieces cut from ((PEI/PAA)(PEI/SWNT)5)6 and ((PEI/PAA)(PEI/SWNT)5)8 free-standing films. The tester was calibrated on similar pieces made from cellulose acetate membranes and Nylon threads. ((PEI/PAA)(PEI/SWNT)5)6 and ((PEI/PAA)(PEI/SWNT)5)8 samples had an average TEM thickness of 0.75 and 1.0 /um, respectively. Their typical stress (ct) vs strain (e) curves differed quite markedly from stretching curves seen previously... 

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