## RADIUS

Because of the broad support and the ubiquitous nature of the **RADIUS** protocol, it is often used by ISPs and enterprises to manage access to the Internet or internal networks , wireless networks , and integrated e-mail services. These networks may incorporate modems , DSL , access points

**wikipedia.org**| 2011/9/21 8:35:11

## Radius

In classical geometry , a **radius** of a circle or sphere is any line segment from its center or axis of symmetry to its perimeter . By extension, the **radius** of a circle or sphere is the length of any such segment, which is half the diameter . [ 1 ] If the object does not have an obvious

**wikipedia.org**| 2011/5/25 17:36:06

## Ionic radius

nucleus; consequently, the other electrons are more strongly attracted to the nucleus, and the **radius** of the atom gets smaller. Likewise, when an electron is added to an atom, forming an anion, the added electron shields the other electrons from the nucleus, with the result that the size of

**wikipedia.org**| 2011/6/6 10:15:53

## Bohr radius

The Bohr **radius** is a physical constant , approximately equal to the most probable distance between the proton and electron in a hydrogen atom in its ground state . It is named after Niels Bohr , due to its role in the Bohr model of an atom. The precise definition of the Bohr **radius** is

**wikipedia.org**| 2011/7/27 10:14:09

## Einstein radius

The Einstein **radius** is the **radius** of an Einstein ring , and is a characteristic angle for gravitational lensing in general, as typical distances between images in gravitational lensing are of the order of the Einstein **radius** . [ edit ] Derivation The geometry of gravitational lenses

**wikipedia.org**| 2011/4/27 21:40:06

## Stokes radius

The Stokes **radius** , Stokes-Einstein **radius** , or hydrodynamic **radius** R H , named after George Gabriel Stokes , is not the effective **radius** of a hydrated molecule in solution as often mentioned. Rather it is the **radius** of a hard sphere that diffuses at the same rate as the molecule. The

**wikipedia.org**| 2010/9/26 12:34:34

## Spectral radius

In mathematics , the spectral **radius** of a square matrix or a bounded linear operator is the supremum among the absolute values of the elements in its spectrum , which is sometimes denoted by ρ(·). Contents 1 Matrices 2 Theorem (Gelfand's formula, 1941) 3 Bounded linear

**wikipedia.org**| 2011/9/3 20:57:08

## Atomic radius

The atomic **radius** of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the nucleus to the boundary of the surrounding cloud of electrons . Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions

**wikipedia.org**| 2011/8/30 1:53:43