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Wyszukujesz frazę "Li, Qinghua" wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
First-principles calculations of electronic structure of rhodochrosite with impurity
Autorzy:
He, Guichun
Li, Kun
Guo, Tengbo
Li, Shaoping
Huang, Chaojun
Zeng, Qinghua
Powiązania:
https://bibliotekanauki.pl/articles/1449610.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rhodochrosite
first principles calculations
electronic structure
density of states
Opis:
The electronic structure of rhodochrosite containing impurity defects is studied by using the first principles density functional theory. The energy band structure, density of states and electronic distribution are calculated for rhodochrosite crystal models with various impurities (e.g., Cu, Ca, Mg, Zn, Fe). This paper discusses the effects of such defects on the electronic structure of rhodochrosite. The calculation results show that the impurity defects have a great impact on the surface electrical properties of rhodochrosite. For example, Ca and Mg impurities reduce the semiconductor width of rhodochrosite. Both Ca and Mg atoms in orbital bonding act as electron donors in which Ca3p and Mg2p orbits provide electrons while O2p orbits receive electrons. Moreover, the more number of valence electrons of Mn is the weaker covalent interaction between Mn and O atoms will be. Meanwhile, decrease of the total energy of rhodochrosite, makes the structure more stable. When Fe, Zn and Cu impurities are contained, the forbidden gap becomes narrower, which improves the conductivity of rhodochrosite. In addition, impurity bands will be formed in the 3d orbits of rhodochrosite as shown in its density of states, and the number of electrons in 3d orbits will increase. This weakens the covalence of O atoms, decreases the population values of O-Mn, increases the bond length, and enhances the ionicity of O-Mn bonds. The impurity of all defects considered in this study have shown an improved conductivity of rhodochrosite, and increased hole concentration of Mn atoms, which will be of great benefit to the adsorption of anionic collectors and enhance the electrochemical properties for rhodochrosite flotation process.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 195-203
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue Behavior of MIG-Welded 7N01-T4 Aluminum Alloy with Different V-Groove Angles
Autorzy:
Ma, Zhongwei
Li, Qinghua
Ma, Lin
He, Zhaokun
Liang, Zhimin
Powiązania:
https://bibliotekanauki.pl/articles/351758.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
7N01-T4 aluminum alloy
MIG welding
V-groove angle
fatigue
fracture
Opis:
7N01-T4 aluminum alloy was welded by metal inert gas welding and the influence of V-groove angle on joint fatigue properties was investigated. The results indicate that the volume of fusion zone (FZ) and the grains in FZ become small when the groove angle decreases to 50° from 70°. Most pores distribute at the FZ edge and fewer pores are formed in the small angle joint. The fatigue crack mainly initiates at the transition region between the weld passes due to the pore concentration. The small angle contributes to increasing joint fatigue properties, especially at the low stress level. The fatigue strength of 50° joint is 103.06 MPa which is 15.3% higher than that of 70° joint.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 4; 1577-1584
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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