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Wyszukujesz frazę "82.33.Pt" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Mechanochemistry and the Other Branches of Chemistry: Similarities and Differences
Autorzy:
Takacs, L.
Powiązania:
https://bibliotekanauki.pl/articles/1489940.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
82.33.Pt
82.30.-b
Opis:
It is argued that mechanical action can induce a unique chemical reaction, if enough mechanical energy is concentrated in the bonds involved in the process to bypass the activation energy. This can happen at crack tips, at the core of dislocations, or at the asperities of colliding or sliding surfaces. A mechanical reaction is always complex, as the macroscopic work is distributed among many possible reaction sites. In comparison, an elementary photochemical reaction is induced by a single photon, while thermochemical reactions rely on the accidental concentration of energy by thermal fluctuations. The paper also compares mechanochemical synthesis in a ball mill with reactions under well-defined loading conditions and mechanochemical experiments carried out on the molecular scale. Closer interaction among those branches of mechanochemistry is urged.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 711-714
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
What Is Unique About Mechanochemical Reactions?
Autorzy:
Takacs, L.
Powiązania:
https://bibliotekanauki.pl/articles/1383095.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
82.33.Pt
82.30.-b
Opis:
Mechanochemical reactions can provide compounds, phases, and microstructures that are essentially different from the products of ordinary reactions. In this paper, the origin of this uniqueness is discussed in light of the recent advances of the field. It is claimed that the local availability of large batches of energy, well above kT, is the key feature of mechanochemical reactions. As a consequence, reactions that cannot occur thermally become possible, similarly to the reactions induced by the energy of photons in photochemistry. However, the situation is more complex, as macroscopic deformation affects many defect sites simultaneously. The direction of the mechanical load relative to the orientation of a molecule or the crystallographic axes of a solid can be important. Many mechanochemical reactions of organic compounds take place at low milling energy that is not sufficient to break primary bonds, but the gentle mechanical grinding can influence the relative position of macromolecules, leading to the formation of unique cocrystals and compounds. In inorganic systems, unusual products form due to forced mixing and the high defect density generated by intense milling.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 1040-1043
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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