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A delta ray is a secondary electron with enough energy to escape a significant distance away from the primary radiation beam and produce further ionization. [ 1 ] : 25 The term is sometimes used to describe any recoil particle caused by secondary ionization .
The delta function was introduced by physicist Paul Dirac, and has since been applied routinely in physics and engineering to model point masses and instantaneous impulses. It is called the delta function because it is a continuous analogue of the Kronecker delta function, which is usually defined on a discrete domain and takes values 0 and 1.
The Kramers–Heisenberg dispersion formula is an expression for the cross section for scattering of a photon by an atomic electron.It was derived before the advent of quantum mechanics by Hendrik Kramers and Werner Heisenberg in 1925, [1] based on the correspondence principle applied to the classical dispersion formula for light.
The delta potential is the potential = (), where δ(x) is the Dirac delta function. It is called a delta potential well if λ is negative, and a delta potential barrier if λ is positive. The delta has been defined to occur at the origin for simplicity; a shift in the delta function's argument does not change any of the following results.
Limits of the model as the lattice spacing is sent to zero (and various limits are taken for variables appearing in the theory) describes integrable field theories, both non-relativistic such as the nonlinear Schrödinger equation, and relativistic, such as the sigma model, the sigma model (which is also a principal chiral model) and the sine ...
Shannon–Weaver model of communication [86] The Shannon–Weaver model is another early and influential model of communication. [10] [32] [87] It is a linear transmission model that was published in 1948 and describes communication as the interaction of five basic components: a source, a transmitter, a channel, a receiver, and a destination.
To achieve high signal-to-noise ratio, delta modulation must use oversampling techniques, that is, the analog signal is sampled at a rate several times higher than the Nyquist rate. Derived forms of delta modulation are continuously variable slope delta modulation, delta-sigma modulation, and differential modulation.
In quantum mechanics, the particle in a one-dimensional lattice is a problem that occurs in the model of a periodic crystal lattice.The potential is caused by ions in the periodic structure of the crystal creating an electromagnetic field so electrons are subject to a regular potential inside the lattice.