Cross of isocline

In contrast to the fibrous and well-oriented polysaccharides (such as cellulose and chitin), amylose in its natural state is found only in more-or-less spherical starch granules. Amylose is the minor constituent of most starches, and is a linear polymer of a-D-(l—>4)-linked D-glucose residues. The birefringence of starch grains was already well known at the turn of the century, and the cross of isocline pattern between crossed Nicols was interpreted in terms of radially arranged crystallites. Later,... 

Figure 9.14 The cross of isocline. The cross forms an angle with the polarizer axis (P-P). The same angle is formed py the cross and the analyzer axis (A-A). This is the extinction angle x- The intersection of the long axis of the particle with the stream line also gives rise to the same angle. However, the former relationship is utilized to measure x-...

The isoclines divide the phase plane into regions of different signs of the time dependencies of p and rj, as is indicated in Figure 9 in a log—log representation. Consequently, any trajectory can cross the isocline rj only horizontally and in the direction of decreasing p, and it can cross the isocline t]2 only vertically in the direction of increasing tj. Further, rj2 crosses the line rj = 0 at the maximum p = 1/Vb, and both isoclines approach the final point (0,1) with the same slope. 

Circular Polariscope - The isoclinic lines can be removed if crossed quarter wave plates are placed on either side of the test cell but between the polarizers with the incident polarization at an angle of 0 = 45 to either of the quarter wave plate axes, with the second quarter wave plate axes perpendicular to the first as shown in the optical section of Fig. 8. This configuration is called a circular polariscope. The necessary fluid handling and high voltage systems are also shown in Fig. 8, specifically for Kerr electro-optic field mapping measurements in highly purified water. 

Bands of equal d will be black in monochromatic light. They are coloured in white light, with the exception of the zero-order band, which is black. These are the isochromatics and are related to the magnitude of the principal refractive indices. Bands of equal are always black and move if the polarizer and analyzer are rotated in the crossed position. These bands are related to the direction of the principal refractive indices and are the isoclinics. 

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