The graphite ore from Australia is a sort of the low-grade and fine-scaled graphite ore. On the basis of the optimum rough grinding fineness, an open and a closed circuit tests were conducted which consist of one rougher, one scavenging, then four-time-regrinding and five-time-cleaning to the rough concentrate, one grinding and scavenging to the mixture of middling1~3, and the middling4~6 returned to the rougher, cleaning1 and cleaning2 respectively. Taking the kerosene, pine oil, lime as flotation reagents, the concentrate with grade improvement from 12.78% to 90.5% was achieved through the routine flotation method, as the flotation recovery rate reached to 92.46%.

\par We present a formulation and implementation of the DFT+\textit{U} method within the framework of linear combination of numerical atomic orbitals (NAO). Our implementation not only enables single-point total energy and electronic-structure calculations but also provides access to atomic forces and stresses, hence allowing for full structure relaxations of periodic systems. Furthermore, our implementation allows one to deal with non-collinear spin texture, with the spin-orbit coupling (SOC) effect treated self-consistently. The key aspect behind our implementation is a suitable definition of the correlated subspace when multiple atomic orbitals with the same angular momentum are used, and this is addressed via the ``Mullken charge projector" constructed in terms of the first (most localized) atomic orbital within the $d/f$ angular momentum channel. The important Hubbard $U$ and Hund $J$ parameters can be estimated from a screened Coulomb potential of the Yukawa type, with the screening parameter either chosen semi-empirically or determined from the Thomas-Fermi screening model. Benchmark calculations are performed for four late transition metal monoxide bulk systems, i.e., MnO, FeO, CoO, and NiO, and for the 5$d$-electron compounds IrO$_2$. For the former type of systems, we check the performance of our DFT+$U$ implementation for calculating band gaps, magnetic moments, electronic band structures, as well as forces and stresses; for the latter, the efficacy of our DFT+$U$+SOC implementation is assessed. Systematic comparisons with available experimental results, and especially with the results from other implementation schemes are carried out, which demonstrate the validity of our NAO-based DFT+$U$ formalism and implementation.

The combination of density functional theory with dynamical mean-field theory (DFT+DMFT) has become a powerful first-principles approach to tackle strongly correlated materials in condensed matter physics. The wide use of this approach relies on robust and easy-to-use implementations, and its implementation in various numerical frameworks will increase its applicability on the one hand and help crosscheck the validity of the obtained results on the other. In this work, we develop a formalism within the linear combination of numerical atomic orbital (NAO) basis set framework, which allows for merging of NAO-based DFT codes with DMFT quantum impurity solvers. The formalism is implemented by interfacing two NAO-based DFT codes with three DMFT impurity solvers, and its validity is testified by benchmark calculations for a wide range of strongly correlated materials, including 3d transition metal compounds, lanthanides, and actinides. Our work not only enables DFT+DMFT calculations using popular and rapidly developing NAO-based DFT code packages but also facilitates the combination of more advanced beyond-DFT methodologies available in these codes with the DMFT machinery.

Using first-principles calculations, we studied the dissolution and diffusion behaviors of H/He atom in perfect fcc-Fe and vacancy capture multiple H/He atoms meachanism in fcc-Fe. The calculation results show that H/He atom prefers to occupy octahedral site, and they diffused along octahedral site-tetrahedral site-octahedral site in perfect fcc-Fe. Inside vacancy, H atom prefers to occupy octahedral site, while He atom prefers to occupy the vacancy center. The exist of H/He atom would decrease the vacancy formation energy. According to capture energies, a vacancy can trap five H atoms in fcc-Fe, but more He atoms can be accommodated even when the number of He atoms reaches sixteen. Therefore, the result provides an important theoretical basis to research the mechanism of hydrogen and helium embrittlement.