Solid angle is much, much farther away. The solid angle subtended by the complete ()-dimensional spherical surface of the unit sphere in -dimensional Euclidean space can be defined in any number of dimensions . One often needs this solid angle factor in calculations with spherical symmetry. It is given by the formula where is the gamma function. When is an integer, the gamma function can be computed explicitly. It follows that This gives the expected results of 4 steradians for the 3D sphere bounded by a surface of area and 2 radians for the 2D circle bounded by a circumference of length
Vapor–liquid–solid method the metal droplet). More specifically, Δµ is the difference between the chemical potential of the depositing species (Si in the above example) in the vapor and solid whisker phase. Δµ is the initial difference proceeding whisker growth (when formula_7), while formula_8 is the atomic volume of Si and formula_9 the specific free energy of the wire surface. Examination of the above equation, indeed reveals that small diameters (formula_10100 nm) exhibit small driving forces for whisker growth while large wire diameters exhibit large driving forces. Involves the removal of material from metal-containing solid targets by irradiating the surface with high-powered (~100