An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Number of Results: 4 Search : permanent
permanent
  ماندگار   
mândegâr (#)

Fr.: permanent   

Lasting or remaining without essential change.

Permanent, from M.Fr. permanent, from L. permanentem "remaining," pr.p. of permanere "endure, continue, stay to the end," from per- "through" + manere "stay," cognate with Pers. mândan, as below; → gas.

permanent gas
  گاز ِ ماندگار   
gâz-e mândegâr

Fr.: gaz permanent   

Gas which cannot be liquefied by pressure alone; gas above its critical temperature.

permanent; → gas.

permanent magnet
  آهنربای ِ ماندگار   
âhanrobâ-ye mândegâr

Fr.: aimant permanent   

A piece of magnetic material which, having been → magnetized, retains a substantial proportion of its → magnetization indefinitely. In permanent magnets the magnetic field is generated by the internal structure of the material itself. Atoms and crystals constituting materials are made up of electrons and atomic nuclei. Both the nucleus and the electrons themselves act like little magnets. There is also a magnetic field generated by the orbits of the electrons as they move about the nucleus. So the magnetic fields of permanent magnets are the sums of the nuclear spins, the electron spins and the orbits of the electrons themselves. In many materials, the magnetic fields are pointing in all sorts of random directions and cancel each other out and there is no permanent magnetism. But in certain materials, called → ferromagnets, all the spins and the orbits of the electrons will line up, causing the materials to become magnetic. Many permanent magnets are created by exposing the magnetic material to a very strong external magnetic field. Once the external magnetic field is removed, the treated magnetic material is now converted into a permanent magnet. Overheating a permanent magnet causes the magnet's atoms to vibrate violently and disrupt the alignment of the atomic domains and their dipoles. Once cooled, the domains will not realign as before on their own and will structurally become a temporary magnet (MagLab Dictionary).

permanent; → magnet.

permanent memory
  برم ِ ماندگار   
barm-e mândegâr

Fr.: mémoire permanente   

Storage capacity which does not depend on a continuous supply of power, e.g. disks, magnetic tapes, etc.

permanent; → memory.