Results 21 to 30 of about 52,754 (240)

Inhomogeneous Big-Bang Nucleosynthesis in Light of Recent Observations [PDF]

open access: yes, 1998
We consider inhomogeneous big bang nucleosynthesis in light of the present observational situation. Different observations of He-4 and D disagree with each other, and depending on which set of observations one uses, the estimated primordial He-4 ...
Kainulainen, K.   +2 more
core   +2 more sources

Hydrogen Tunneling in Stoichiometric and Catalytic Reactions involving Transition Metals

open access: yesChemCatChem, Volume 15, Issue 24, December 19, 2023., 2023
An overview on the importance of the participation of hydrogen tunneling in E−H bond activation reactions (E=C, O, Si…) mediated by transition metals is presented. Understanding when hydrogen tunneling occurs can be a powerful tool for designing new catalysts to perform challenging reactions.
Jon M. Matxain, Miguel A. Huertos
wiley   +1 more source

Núcleos exóticos e síntese dos elementos químicos

open access: yesQuímica Nova, 2012
We have around ninety chemical elements available in nature, which were produced mainly by nuclear reactions inside stars. The fusion reactions are the main synthesis process which generates the light and intermediate masses elements.
Nilton Teruya, Sérgio Barbosa Duarte
doaj   +1 more source

Impact of AGB Stars on the Chemical Evolution of Neutron-Capture Elements

open access: yesUniverse, 2022
In this review, we discuss the impact of s-process nucleosynthesis in asymptotic giant branch stars on the enrichment of heavy elements. We review the main steps made on this subject in the last 40 years and discuss the importance of modelling the ...
Gabriele Cescutti, Francesca Matteucci
doaj   +1 more source

A Proposal for a Low‐Frequency Axion Search in the 1–2 μ$\umu$ eV Range and Below with the BabyIAXO Magnet

open access: yesAnnalen der Physik, Volume 535, Issue 12, December 2023., 2023
This article describes the implementation of low‐frequency axion haloscope setups inside the future BabyIAXO magnet. The RADES proposal has a potential sensitivity to the axion‐photon coupling down to values corresponding to the KSVZ model, in the mass range between 1 and 2 μ$\umu$eV.
Saiyd Ahyoune   +29 more
wiley   +1 more source

The NuGrid AGB Evolution and Nucleosynthesis Data Set

open access: yesUniverse, 2022
Asymptotic Giant Branch (AGB) stars play a key role in the chemical evolution of galaxies. These stars are the fundamental stellar site for the production of light elements such as C, N and F, and half of the elements heavier than Fe via the slow neutron
Umberto Battino   +4 more
doaj   +1 more source

Kinetics of the tautomerization of thioimidic acids R−C(SH)NH → R−C(S)NH2: For R = H, F, HO, CN, NC, H2N, HC(O), HC(S), HC≡ C, CH3, CF3, H2C=CH, HOCH2, H2NCH2,CH3C(O), C2H5, (CH3)2CH, C6H5

open access: yesInternational Journal of Chemical Kinetics, Volume 55, Issue 11, Page 731-742, November 2023., 2023
Abstract The kinetics of the tautomerization of thio‐imidic acids RC(SH)NH were determined at low (50–300 K) and high (500–1500 K) temperatures as R was varied to encompass mono‐ and diatomic species H, F, HO, NC, CN through H2N, HC(O), HC(S), HC≡ C, H3C, F3C, HOCH2, H2C=CH, CH3C(O), H2NCH2 and including ethyl, isopropyl and phenyl groups. The presence
Judith Würmel, John M. Simmie
wiley   +1 more source

Structure formation cosmic rays: Identifying observational constraints [PDF]

open access: yesSerbian Astronomical Journal, 2005
Shocks that arise from baryonic in-fall and merger events during the structure formation are believed to be a source of cosmic rays. These "structure formation cosmic rays" (SFCRs) would essentially be primordial in composition, namely, mostly made of ...
Prodanović T., Fields B.D.
doaj   +1 more source

General relativistic effects on neutrino-driven wind from young, hot neutron star and the r-process nucleosynthesis [PDF]

open access: yes, 1999
Neutrino-driven wind from young hot neutron star, which is formed by supernova explosion, is the most promising candidate site for r-process nucleosynthesis.
Hideyuki Tagoshi   +9 more
core   +2 more sources

Ar+ ArH+ Reactive Collisions of Astrophysical Interest: The Case of 36Ar

open access: yesChemPhysChem, Volume 24, Issue 20, October 17, 2023., 2023
A complete theoretical investigation of the 36Ar+36ArH+ reactive collision involving the most abundant Argon isotope in the interstellar medium. Abstract The reactive collision between 36Ar and the 36ArH+ species has been investigated by means of quantum mechanical (QM), quasiclassical trajectories (QCT) and statistical quantum mechanical (SQM ...
María Judit Montes de Oca‐Estévez   +5 more
wiley   +1 more source

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