منابع مشابه
HELIUM , SOLID 1 Helium , Solid
Helium was first solidified at the famous Kamerlingh Onnes low-temperature physics laboratories in Leiden by W. H. Keesom [1] on June 25, 1926. The initial experiments by Sir Francis Simon at Oxford University and by Keesom and their collaborators focused on the melting curve, the specific heat, and the thermal conductivity of solid helium as a test of our early understanding of solids. These m...
متن کاملThe ionization of helium by neutral helium atoms.
A method is described for investigating the ionization produced in helium by collisions between quasi-stationary atoms—that is, atoms possessing only thermal velocities—and a beam of neutral helium atoms with kinetic energy less than 100 eV. Ionization is shown to begin when the kinetic energy of the bombarding atoms is twice as great as the minimum kinetic energy which electrons must possess i...
متن کاملThe Dynamics and Helium Distribution in Hydrogen-helium Fluid Planets
In the preceding paper (Paper I) we discussed the thermodynamic and microscopic transport properties of hydrogen-helium fluid mixtures. These results are used in the present paper for a semiquantitative analysis of the thermal and compositional history of an evolving hydrogenhelium planet such as Jupiter or Saturn. First, the evolution of a homogeneous planet with no first-order phase transitio...
متن کاملFine structure of helium and light helium-like ions
Calculational results are presented for the fine-structure splitting of the 2P state of helium and helium-like ions with the nuclear charge Z up to 10. Theoretical predictions are in agreement with the latest experimental results for the helium fine-structure intervals as well as with the most of the experimental data available for light helium-like ions. Comparing the theoretical value of the ...
متن کاملAlkali-helium snowball complexes formed on helium nanodroplets.
We systematically investigate the formation and stability of snowballs formed by femtosecond photoionization of small alkali clusters bound to helium nanodroplets. For all studied alkali species Ak = (Na,K,Rb,Cs) we observe the formation of snowballs Ak(+)He(N) when multiply doping the droplets. Fragmentation of clusters Ak(N) upon ionization appears to enhance snowball formation. In the case o...
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ژورنال
عنوان ژورنال: Nature
سال: 1895
ISSN: 0028-0836,1476-4687
DOI: 10.1038/051586a0