Helium vessel. Container holding liquid helium,a substance used as a refrigerant in low temperature research; gaseous helium is also liquified when large amounts are being transported. Helium liquifies at -268.9 degrees Celsius (C) and must be cooled to -272.2 C at a pressure of 25 atmospheres before it will solidify; these temperatures are only just above absolute zero (- 273.18 C). If liquid helium is cooled to -270.98 C it greatly changes its properties and is known as Helium II. Helium II has a high thermal conductivity,no internal temperature differences and zero viscosity. The main source of helium is natural gas,in which it is an impurity | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Winters, Charles D. |
Taille de l’image : | 2516 px × 3582 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : |
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