Results 1 to 10 of about 493,297 (123)

Helium Emissions Observed in Ground-Based Spectra of Solar Prominences [PDF]

, 2012
The only prominent line of singly ionized helium in the visible spectral range, helium-II 4686 A, is observed together with the helium-I 5015 A singlet and the helium-I 4471 A triplet line in solar prominences.
Bianda, Michele, Ramelli, Renzo, Stellmacher, Goetz, Wiehr, Eberhard   +3 more
core   +2 more sources

Cavitation pressure in liquid helium [PDF]

, 2001
Recent experiments have suggested that, at low enough temperature, the homogeneous nucleation of bubbles occurs in liquid helium near the calculated spinodal limit. This was done in pure superfluid helium 4 and in pure normal liquid helium 3. However, in
B. M. Abraham, B. M. Abraham, C. E. Campbell, D. M. Jezek, F. Caupin, F. Caupin, F. Caupin, F. Dalfovo, G. H. Bauer, G. W. Waters, H. J. Maris, H. J. Maris, H. Lambaré, J. A. Nissen, J. Boronat, J. C. Wheatley, J. Casulleras, J. Wilks, K. Dransfeld, Lord Rayleigh, M. A. Solis, M. Guilleumas, M. Guilleumas, M. Kollar, M. P. Bertinat, P. Roche, S. Balibar, S. Balibar, S. Balibar, S. N. Burmistrov, W. H. Press, X. Chavanne   +31 more
core   +3 more sources

Electric-field-induced helium-helium resonances

Physical Review A, 2019
The tunability of the helium-helium interaction through an external electric field is investigated. For a static external field, electric-field induced resonances and associated electric-field induced bound states are calculated for the $^4$He-$^4$He, $^3$He-$^4$He, and $^3$He-$^3$He systems. Qualitative agreement is found with the literature for the $^
Guan, Qingze, Blume, Doerte
openaire   +3 more sources

The helium trimer with soft-core potentials [PDF]

, 2011
The helium trimer is studied using two- and three-body soft-core potentials. Realistic helium-helium potentials present an extremely strong short-range repulsion and support a single, very shallow, bound state.
A. Kievsky, A. Kievsky, A.K. Motovilov, A.R. Holt, A.R. Janzen, B.D. Esry, C. Romero-Redondo, C. Romero-Redondo, E. Garrido, E. Nielsen, E. Nielsen, E.A. Kolganova, E.A. Kolganova, F. Luo, F.E. Harris, H. Suno, J. Stecher von, K.T. Tang, M. Jeziorska, M. Lewerenz, M.V. Zhukov, P. Barletta, P. Barletta, P. Barletta, P. Barletta, R. Grisenti, R.A. Aziz, R.A. Aziz, T. Korona, V. Efimov, V. Efimov, V. Roudnev, W. Cencek, W. Schoellkopf, W. Schollkopf   +34 more
core   +3 more sources

Rb*He_n exciplexes in solid 4_He [PDF]

, 2006
We report the observation of emission spectra from Rb*He_n exciplexes in solid 4He. Two different excitation channels were experimentally identified, viz., exciplex formation via laser excitation to the atomic 5P3/2 and to the 5P1/2 levels.
Hofer, A., Moroshkin, P., Nettels, D., Ulzega, S., Weis, A.   +4 more
core   +2 more sources

The Hottest Horizontal-Branch Stars in omega Centauri - Late Hot Flasher vs. Helium Enrichment

, 2007
UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars.
Bono, G., Calamida, A., Dreizler, S., Lanz, T., Moehler, S., Monelli, M., Nonino, M., Sweigart, A. V.   +7 more
core   +2 more sources

Can R CrB stars form from the merger of two helium white dwarfs?

, 2012
Due to orbital decay by gravitational-wave radiation, some close-binary helium white dwarfs are expected to merge within a Hubble time. The immediate merger products are believed to be helium-rich sdO stars, essentially helium main-sequence stars.
Benz, Brown, C. Simon Jeffery, Clayton, Clayton, Cropper, Dinger, Evans, Guerrero, Han, Iben, Jeffery, Jeffery, Kilic, Kilic, Longland, Longland, Lorén-Aguilar, Nelemans, Nelemans, Paczyński, Pakmor, Pandey, Pandey, Paxton, Rebassa-Mansergas, Saio, Saio, Trimble, Warner, Webbink, Weiss, Xianfei Zhang, Yoon, Zhang   +34 more
core   +1 more source

Resistor monitors transfer of liquid helium [PDF]

, 1966
Large resistance change of a carbon resistor at the liquid helium temperature distinguishes between the transfer of liquid helium and gaseous helium into a closed Dewar.
Hesketh, W. D.
core   +1 more source

Rare Helium-Bearing Compound FeO2He Stabilized at Deep-Earth Conditions

, 2018
There is compelling geochemical evidence for primordial helium trapped in Earth’s lower mantle, but the origin and nature of the helium source remain elusive due to scarce knowledge on viable helium-bearing compounds that are extremely rare.
Chen, Changfeng, Feng, Xiaolei, Li, Hefei, Liu, Hanyu, Lu, Cheng, Lv, Jian, Ma, Yanming, Redferm, Simon A. T., Zhang, Jurong   +8 more
core   +1 more source

Free-energy model for fluid helium at high density [PDF]

, 2004
We present a semi-analytical free-energy model aimed at characterizing the thermodynamic properties of dense fluid helium, from the low-density atomic phase to the high-density fully ionized regime. The model is based on a free-energy minimization method
Christophe Winisdoerffer, G. Chabrier, Gilles Chabrier, L. Landau   +3 more
core   +2 more sources