Experimental procedure angles

These values make it evident that the contact angles must be observed rather carefliUy to obtain a value close to 90°. The following experimental procedure is practical to obtain good stabiUty. A container with the particles is placed on the bottom of an ofl-filled vessel with parallel walls, and a drop of the aqueous phase is placed on the powder. The shape of the droplet decides the action to be taken. 

Of course the structural changes represented in Table 1 are much more complex than the simple bond angle plus electronic effect analysis reveals. For example, solvation of the carbene may depend on the details of its structure, and solvation undoubtedly influences chemical and physical properties (Langan et al., 1984). Nonetheless, it is possible to develop a good grasp of the most important properties of aromatic carbenes from the simple considerations described above. Before we proceed to examine these relationships in more detail, the carbene properties of interest must be identified, and the experimental procedures available for measurement of these properties must be critically considered. 

The nonlinearity of the sample was analyzed using the experimental procedure described in Section 3.3 The polarization of the fundamental beam of a YAG laser was continuously varied by means of a quarter waveplate, and the intensity of the second-harmonic signal was measured as a function of the rotation angle of the quarter waveplate. The obtained polarization pattern were then fitted to Eq. (42), which yields the relative values of the expansion coefficients /, g, and h. The experimental results for the transmitted, glass-side-incidence, s-polarizcd signal are shown in Figure 9.20. 

Once the log modulus curve has been adequately fitted by an approximate transfer function G(J ), the phase angle of G( a) is compared with the experimental phase-angle curve. The difference is usually the contribution of deadtime. The procedure is illustrated in Fig. 14.2. 

The experimental procedures of BET, TGA, and XRD have been described in detail elsewhere [8]. The interlayer d-spacing from XRD pattern is determined by the angle of ((X)l) reflection. For the measurement of ion-exchange capacity, SO mg of sample was suspended with 10 cm of NaCl solution (0.1 N), and the pH values were measured with addition of NaOH solution (0.1 N) to obtain the potentiometric titration curve at rocnn temperature. 

We developed an experimental procedure that can be applied to highly viscous polymer blends. In the DSM micro-extruder [6], polymers are blended in the melt, at the desired temperature and pressure, and injected into a small capillary tube which is immediately sealed with a floating plug. This capillary cell is placed in a small window autoclave and a laser beam enters the capillary cell at the lens-shaped bottom end. The intensity of the light scattered by the polymer system is recorded at two scattering angles (as a function of pressure and temperature). 

The experimental procedure is considerably simplified by the modern equipment currently available. Most of the measurements were carried out at a scattering angle of 90° and evaluated by application of the classical Debye equation22, 31, 96),... 

Pore structure analysis methods based upon realistic disordered microstructures may be classified into two types. In one approach, the experimental procedures used to fabricate the material are reproduced, to the greatest extent possible, via molecular simulation, and the resulting amorphous material structure is then statistically analyzed to obtain the desired structural information. In the other approach, adsorbent structural data (e.g., smaU-angle neutron scattering) is used to construct a model disordered porous structure that is statistically consistent with the experimental measurements. As in the first approach, molecular simulations can then be carried out using the derived model structure to obtain the structural characteristics of the original adsorbent. 

For softer, rubbery polymers, a different experimental procedure gives better results. For these experiments we have measured directly the penetration distance of a tiny weighted probe into the cross-sectioned surface of polymer samples. For this purpose we have made use of a Perkin-Elmer Thermomechanical Analyzer equipped with a tip modified to be small enough to provide measurements of the desired resolution. (We are currently using a conical diamond phonograph needle having a tip angle of 60°.)... 

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