scholarly journals Nano-Phase KNa(Si6Al2)O16 in Adularia: A New Member in the Alkali Feldspar Series with Ordered K–Na Distribution

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 649
Author(s):  
Huifang Xu ◽  
Shiyun Jin ◽  
Seungyeol Lee ◽  
Franklin Hobbs
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dft Calculation ◽  
Alkali Feldspar ◽  
Interface Energy ◽  
Slow Cooling ◽  
Functional Theory ◽  
Intermediate Composition ◽  
Host Rocks ◽  
Alkali Feldspars

Alkali feldspars with diffuse reflections that violate C-centering symmetry were reported in Na-bearing adularia, orthoclase and microcline. TEM results indicate elongated nano-precipitates with intermediate composition of KNa(Si6Al2)O16 cause the diffuse reflections. Density functional theory (DFT) calculation indicates ordered distribution of K and Na atoms in the nano-phase with Pa symmetry. K and Na atoms are slightly off special positions for K atoms in the orthoclase structure. Formation of the intermediate nano-phase may lower the interface energy between the nano-phase and the host orthoclase. Previously reported P21/a symmetry was resulted from an artifact of overlapped diffraction spots from the nano-precipitates (Pa) and host orthoclase (C2/m). Adularia, orthoclase and microcline with the Pa nano-precipitates indicate very slow cooling of their host rocks at low temperature.

Effect of Solute Ta on Grain Refinement of Al-7Si-0.3Mg Based Alloys

2022 ◽  
Vol 327 ◽  
pp. 54-64
Author(s):  
Ivo Spacil ◽  
David Holec ◽  
Peter Schumacher ◽  
Jiehua Li
Keyword(s):  
Grain Refinement ◽  
Density Functional ◽  
Dft Calculation ◽  
Interface Energy ◽  
Special Focus ◽  
Grain Refiner ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Sandwich Configuration ◽  
Scanning Electron

Different Ta concentrations together with stochiometric grain refiner (Al-2.2Ti-1B) in Al-Si-Mg based alloys were investigated with the aim to elucidate grain refinement mechanisms. Post-solidification microstructure was characterised using optical microscopy and scanning electron microscopy (SEM), with a special focus on the Ta-rich layer (more likely to be Al3Ta) on the basal planes (0001) of TiB2. A significant grain refinement was observed by using the solute Ta together with stochiometric grain refiner (Al-2.2Ti-1B). In order to further elucidate the formation of Ta-rich layer on the basal planes (0001) of TiB2, the Density Functional Theory (DFT) calculation were also performed to determine the interface energies of different interfaces and sandwich configurations, including Al (111), Al3Ti (112) and Al3Ta (112) at the interface of TiB2 basal plane (0001). It was found that the interface energy for Ti-terminated TiB2 at the interface throughout all configurations involved in this paper is lower than that for B-terminated TiB2, indicating that Ti-terminated TiB2 is more favourable. It was also found that the Al3Ta configuration yields the same interface energies as the Al3Ti configuration. Furthermore, the interface energy of the sandwich configuration also shows nearly identical values along the TiB2 // Al3Ti and TiB2 // Al3Ta interface energy, strongly indicating that the solute Ti can be fully replaced by the solute Ta.

scholarly journals Do two oxidants (ferric-peroxo and ferryl-oxo species) act in the biosynthesis of estrogens? A DFT calculation

RSC Advances ◽  
2018 ◽  
Vol 8 (27) ◽  
pp. 15196-15201 ◽  
Author(s):  
Xiang-Yun Wang ◽  
Hui-Min Yan ◽  
Yan-Li Han ◽  
Zhu-Xia Zhang ◽  
Xiao-Yun Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dft Calculation ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Two Oxidants ◽  
Ferric Peroxo

Density functional theory calculations were performed in order to reveal the mysterious catalytic step of the biosynthesis of estrogens.

Spin Alignment Studies on the Muon-Site Determination in La2CuO4

2020 ◽  
Vol 860 ◽  
pp. 154-159
Author(s):  
Muhammad Redo Ramadhan ◽  
Irwan Ramli ◽  
Dita Puspita Sari ◽  
Budhy Kurniawan ◽  
Azwar Manaf ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Potential Distribution ◽  
Density Functional ◽  
Dft Calculation ◽  
Minimum Energy ◽  
Point Dipole ◽  
Spin Alignment ◽  
Functional Theory ◽  
Muon Site ◽  
Insulating Gap

Here we report spin-alignment contributions to muon coordinate calculated utilizing density functional theory (DFT) calculation. We estimated four different antiferromagnetic (AF) spin alignments in La2CuO4. We observed small changes by adjusting spin configurations in DFT calculations. Cu-spin value of 0.61 µB is constant in all calculations. The insulating gap of 1.9 eV is unchanged in all configurations. Muon coordinate was defined as the most minimum energy in atomic potential distribution. By assuming that Cu-spin is a point dipole for each atom, internal fields for muon were calculated and compared to known experimental results.

WORK FUNCTION OF BORON CARBIDE: A DFT CALCULATION

2012 ◽  
Vol 19 (04) ◽  
pp. 1250040 ◽  
Author(s):  
CHUNSHAN HE ◽  
ZHIBING LI ◽  
WEILIANG WANG
Keyword(s):  
Density Functional Theory ◽  
Boron Carbide ◽  
Work Function ◽  
Density Functional ◽  
Dft Calculation ◽  
Slab Model ◽  
Functional Theory ◽  
Work Functions

The work functions of (001) and (00-1) surfaces of B4C are investigated with density functional theory and symmetry slab model. These two surfaces are found to be almost nonpolarized and their work functions are 5.15 eV and 5.46 eV, respectively.

Luminescence and density functional theory (DFT) calculation of undoped nitridosilicate phosphors for light-emitting diodes

2012 ◽  
Vol 22 (12) ◽  
pp. 5828 ◽  
Author(s):  
Chiao-Wen Yeh ◽  
Yun-Ping Liu ◽  
Zhi Ren Xiao ◽  
Yin-Kuo Wang ◽  
Shu-Fen Hu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dft Calculation ◽  
Light Emitting Diodes ◽  
Functional Theory ◽  
Light Emitting

scholarly journals Electronic Properties of Ethylene Glycol and Styrene Glycol: DFT Calculation

2021 ◽  
Vol 9 (8) ◽  
pp. 3040-3045
Author(s):  
Mahnaz Fatima
Keyword(s):  
Density Functional Theory ◽  
Ethylene Glycol ◽  
Charge Density ◽  
Density Functional ◽  
Dft Calculation ◽  
Theoretical Study ◽  
Density Of State ◽  
Functional Theory ◽  
Computational Program ◽  
State Charge

Abstract: In this paper we worked on a theoretical study of Ethylene glycol and styrene glycol Which is based on density functional theory, implement in computational program SIESTA with use of general gradient approximation (GGA) of Perdew, Burke and Emzerhof (PBE) scheme for an account of exchange co-relation effect to obtain density of state , projected density of state and charge density. Keywords: Density functional theory, SIESTA, Density of state .Projected density of state ,charge density .

DFT Calculation for Oxidation Reaction of SiC(0001)

2019 ◽  
Vol 963 ◽  
pp. 208-212
Author(s):  
Tomoya Ono
Keyword(s):  
Density Functional Theory ◽  
Oxidation Reaction ◽  
Density Functional ◽  
Dft Calculation ◽  
Density Functional Theory Calculation ◽  
Oxygen Molecule ◽  
Functional Theory ◽  
Theory Calculation

The reaction-limiting process for the oxidation of SiC(0001) was investigated by density functional theory calculation. I found that the oxygen molecule insertion to the interfacial SiC bonds is the limiting process and the barrier is 3.21 eV. It is also found that the CO detachment is not limiting process because the barrier becomes small when the interfacial C atom is surrounded by three O atoms.

Sign in / Sign up

Export Citation Format

Share Document