fermi constant
41Hierarchy problem — In theoretical physics, a hierarchy problem occurs when the fundamental parameters (couplings or masses) of some Lagrangian are vastly different (usually larger) than the parameters measured by experiment. This can happen because measured… …
42Ohmic contact — An ohmic contact is a region on a semiconductor device that has been prepared so that the current voltage (I V) curve of the device is linear and symmetric. If the I V characteristic is non linear and asymmetric, the contact is not ohmic, but is… …
43Chandrasekhar limit — When a star starts running out of fuel, it usually cools off and collapses (possibly with a supernova) into one of three compact forms, depending on its total mass: a White Dwarf, a big lump of Carbon and Oxygen atoms, almost like one huge… …
44nature, philosophy of — Introduction the discipline that investigates substantive issues regarding the actual features of nature as a reality. The discussion here is divided into two parts: the philosophy of physics and the philosophy of biology. In this… …
45Chemical potential — Chemical potential, symbolized by μ, is a measure first described by the American engineer, chemist and mathematical physicist Josiah Willard Gibbs. It is the potential that a substance has to produce in order to alter a system.[1] In broadest… …
46List of eponyms — An eponym is a person (real or fictitious) from whom something is said to take its name. The word is back formed from eponymous , from the Greek eponymos meaning giving name . NOTOC Here is a list of eponyms:A B C D E F G H I–J K L–ZA* Achilles,… …
47SOLIDES (PHYSIQUE DES) — Ce qui différencie à première vue un solide des autres états de la matière (gaz, liquides, plasmas), c’est la résistance qu’il oppose à des forces mécaniques, sa tendance à garder un volume constant. De tout temps on s’est servi de cette… …
48particle accelerator — accelerator (def. 7). [1945 50] * * * Device that accelerates a beam of fast moving, electrically charged atoms (ions) or subatomic particles. Accelerators are used to study the structure of atomic nuclei (see atom) and the nature of subatomic… …
49Drake equation — This article is about Frank Drake s equation. For the Tub Ring music album, see Drake Equation (album). The Drake equation (sometimes called the Green Bank equation or the Green Bank Formula) is an equation used to estimate the number of… …
50Absolute zero — For other uses, see Absolute Zero (disambiguation). Absolute zero is the theoretical temperature at which entropy reaches its minimum value. The laws of thermodynamics state that absolute zero cannot be reached using only thermodynamic means. A… …
