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A positronic brain is a fictional technological device, originally conceived by science fiction writer Isaac Asimov. [ 1 ] [ 2 ] It functions as a central processing unit (CPU) for robots , and, in some unspecified way, provides them with a form of consciousness recognizable to humans .
The positron or antielectron is the particle with an electric charge of +1e, a spin of 1/2 (the same as the electron), and the same mass as an electron.It is the antiparticle (antimatter counterpart) of the electron.
Mach number A dimensionless quantity representing the ratio of the speed of an object moving through a fluid to the local speed of sound. Mach's principle The proposition that the existence of absolute rotation (the distinction of local inertial frames vs. rotating reference frames) is determined by the large-scale distribution of matter. machine
Meaning SI unit of measure alpha: alpha particle: angular acceleration: radian per second squared (rad/s 2) fine-structure constant: unitless beta: velocity in terms of the speed of light c: unitless beta particle: gamma: Lorentz factor: unitless photon: gamma ray: shear strain: radian
According to physicist Philip Warren Anderson, the use of the term "condensed matter" to designate a field of study was coined by him and Volker Heine, when they changed the name of their group at the Cavendish Laboratories, Cambridge, from Solid state theory to Theory of Condensed Matter in 1967, [10] as they felt it better included their interest in liquids, nuclear matter, and so on.
It has a mean lifetime of 0.12 ns and decays preferentially into two gamma rays with energy of 511 keV each (in the center-of-mass frame). Para-positronium can decay into any even number of photons (2, 4, 6, ...), but the probability quickly decreases with the number: the branching ratio for decay into 4 photons is 1.439(2) × 10 −6. [1]
Ionic conductivity (denoted by λ) is a measure of a substance's tendency towards ionic conduction. Ionic conduction is the movement of ions . The phenomenon is observed in solids and solutions.
As , where is the scattering cross section for electrons and holes at a scattering center and is a thermal average (Boltzmann statistics) over all electron or hole velocities in the lower conduction band or upper valence band, temperature dependence of the mobility can be determined. In here, the following definition for the scattering cross ...