Angle definitions

Euler angles, definition of 84 Exchange rate O 31 Extrusion 142... 

Name, Symbol radian, rad-(plane angle) Definition The radian is the plane angle between two radii of a circle which cuts off, on the circumference, an arc equal in length to the radius. 

The bases are in syn or anti orientation. The orientation of the base relative to the sugar moiety is defined by torsion angle x which is constrained by steric interactions, and by the anomeric effect. The main conformations are referred to as syn and anti (see Fig. 17.5). In syn, j X is close to 0° (sp for torsion angle definition, see Box 13.3 Fig. 13.12), and the base is I oriented "above the ribose ring causing steric interactions which in the anti conformation with x close to 180° (ap) are avoided. The anti conformation is therefore preferred and is the j only form observed in double-helical DNA and RNA. An exception is the left-handed Z-DNA with alternating purine/pyrimidine nucleotide sequence where the purines are in the syn conformation. 

Fig. 3.3.4 Geometry and angle definition for mechanical sample spinning, n denotes the orientation of a crystallite in the spinner or the preferential axis of the sample. Adapted firom [Harl] with permission from the American Institute of Physics.

Dihedral angle definition. The dihedral angle of atoms A,B,C,D is shown as (A) a positive angle by counter-clockwise rotation of the B-A bond about the B-C bond ... 

As previously stated, there are two units in this class the radian, symbol rad, the SI unit of the quantity plane angle and the steradian, symbol sr, the SI unit of the quantity solid angle. Definitions of these units are given in Appendix A. 

According to Fresnel, the relationship between the intensity of the reflected light /, and the intensity of the incident light /q involves the angle of incidence a and the angle of refraction p (for angle definitions, see Figure 15-1) ... 

With the restriction of harmonicity (Equation 9.118) and the equivalence (Equation 9.119) between pulsations, the phase angle definition in Equation 9.85 can now be written as... 

Spreading-angle definition. (From Krum, A., Thermal Management Handbook, Electronic Packaging and Interconnection Series, Eds., Krum, A. and Sergent, ]., New York McGraw-FHU, 1998. chap. 5. With permission.)... 

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