Angstrom units, definition

Angstrom units, definition, 128 Anthracene, carcinogenic activity, 45 Anthracenedihydrodiols, synthesis, 45 Arylnitrones, reaction mechanism, 363f... 

Angles, diffraction, table, for various common jmonochromators, 318-327 Angstrom (A), definition, 307 Angstroms, conversion from kX units to, 7, 307... 

Angstrom unit (A), definition, 307 Antimony, determination by x-ray emission spectrography, 328 in silicate, determination by absorption-edge method, 140 in solution, determination by absorption-edge method, 140 Aperture, relative, of x-ray optical system, 113... 

The numerical values of most physical quantities are expressed in terms of units. The distance between two points, for example, can be specified by the number of meters (or feet, Angstroms, etc.). Similarly, time cap be expressed in seconds, days or, say, years. However, the number of days per year varies from one year to another. The quantities, distance (length) and time, as well as mass, are usually chosen to be primary quantities. In terms of them Newton s second law for the force on an object, can be written as force = mass, distance/(time)2. The definition of the primary quantities allows dimensional expressions to be written, such as [force] — MLT-2 in the present example. Note, however, that in everyday life one speaks of the weight of an object (or a person). Of course the weight is not the mass, but rather the force acting on the object by the acceleration due to gravity [acceleration] = LT 2. 

Table 8 Definition of the two-body increments for Zn and Cd, at the experimental lattice parameters. The distances are given both in angstroms and in units of a, the lattice parameter. Also given are the number of hexagonal planes connected by this increment for example, the increment (1-7) connects atoms in plane 1 and plane 3 at a distance of the lattice parameter c... 

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