In order to investigate the propagation characteristics and thermal shock dynamics of multiple explosive sources gas explosion in complex roadways, numerical simulations were conducted using the Fluent software under three types of dual explosive sources arrangements in the H-type tunnel, including the same side, opposite positions, and diagonal positions. It was found that, after the two explosive sources in the tunnel were ignited simultaneously, its prodromic shock wave propagated along the unburned area of the tunnel. When the two shock waves encountered, the pressure superimposed while the impulse canceled out, and the propagation of flame was blocked by the pressure superposition area, resulting in a slowdown or reversal of the speed. Compared to the single source explosion, the dual explosive sources led to a higher pressure in specific areas such as contact lane, center of bifurcation, and sidewalls. Extreme pressure zones occur at the closed end of the roadway under same-side and diagonal arrangement conditions and at the center of the bifurcation under the opposite arrangement condition.

Recently, a large number of theoretical and experimental studies have reported the emergence of a new sp³ clathrate XB₃C₃, where X represents different metal doping elements. The potential high-temperature superconducting materials have been discovered. New-typical cage material with both strong covalent and superconducting properties has important scientific research significance. In recent years, Ac discovered as the first element of the actinide series, AcH₁₀ has a superconducting transition temperature (T_c) of 251 K, making it a potential room temperature superconductor. Therefore, in this article, first principles density functional theory is used to explore the crystal structure, lattice dynamics, electronic properties, and superconducting properties of AcB₃C₃, AcB₂C₄, and AcB₄C₂ doped with Ac elements based on the cage structures of XB₃C₃, XB₂C₄, and XB₄C₂. Research has found that AcB₂C₄ is difficult to synthesize within the 0–200 GPa range, and AcB₃C₃ exhibits an indirect bandgap semiconductor with a bandgap width of approximately 1.154 eV at atmospheric pressure. Based on the mechanical stability criterion, it can be inferred that AcB₃C₃ and AcB₄C₂ are brittle materials with high hardness and stiffness that are elastically stable. At the same time, AcB₄C₂ exhibits superconducting properties at ambient pressure, with T_c reaching 1.565 K. It has been observed that as pressure increases, the T_c value exhibits a trend of initially decreasing and then increasing. The superconducting mechanism is mainly influenced by intermediate-frequencies phonons, which then shift to the combination of low-frequencies and intermediate-frequencies phonons. This study provides guidance for the experimental synthesis of cage type compound superconducting materials and provides new ideas for exploring superconducting materials with high superconducting transition temperature.

Rare-earth metal superhydrides have attracted much attention because of their high-temperature superconductivity. Since experimental measurements can only determine the structures of rare-earth metal atoms in the superhydrides, first-principles calculations have become an important complementary method for a comprehensive understanding on their structures and physical properties. In this work, the elasticity, lattice dynamics and proton dynamics properties of face-centered cubic CeH₉ and CeH₁₀ with different hydrogen contents but the same Ce lattice structure are investigated comparatively by first-principles calculations. The low hydrogen content is found to favor the elastic and phonon stabilization of face-centered cubic cerium superhydrides expanding to low pressures. At 100–140 GPa, CeH₉ and CeH₁₀ do not have significant proton diffusion at room temperature, but fully transform into the superionic state at 1500 K with diffusion coefficients of 1.6×10⁻⁴−1.2×10⁻⁴ cm²/s and 1.9×10⁻⁴−1.5×10⁻⁴ cm²/s; the diffusion coefficient is positively correlated with temperature and hydrogen content, but negatively correlated with pressure. The findings on the laws of pressure, temperature and hydrogen content affecting the structure and dynamics of cerium superhydrides are obtained, which can be used as a reference for the study of other superhydrides.

In this work, we have performed extensive swarm-intelligence structures searching simulations on the RbBSi compounds within the pressure range from 0 to 100 GPa. We have proposed three different phases of RbBSi, of which the stability, the electronic structure and the potential superconductivity were calculated by first-principles calculations. All predicted phases are thermodynamically and dynamically stable within the studied pressure range. The bands of the three phases crossing the Fermi level indicate the structures are all metallic. In addition, P4/nmm-RbBSi is a superconductor with T_c of 14.4 K at ambient pressure. This work extends the understanding and potential application of alkali metal boron-silicide compounds in the field of superconductor.

Using first principles density functional theory calculations, the crystal structure, electronic properties, and superconductivity characteristics of the ternary hydride Y-Si-H system under high pressure were investigated. The study revealed the existence of thermodynamically stable phases, including YSiH₇, YSiH₉, YSi₂H₁₂, and YSiH₁₈, and thermodynamically metastable phases, namely YSi₂H₁₃, YSi₂H₁₄, and Y₂SiH₁₇. Electronic properties calculations showed that YSiH₇ is insulator and YSi₂H₁₃ is semiconductor, while the remaining hydrides exhibit metallic properties. Superconducting transition temperatures (T_c) were estimated using the McMillan equation, with YSi₂H₁₂ hosting the highest T_c of 43.5 K at 100 GPa. The dynamic stable pressure of YSi₂H₁₄ can be reduced to 40 GPa, and its T_c is 23.8 K which is twice the highest T_c among binary Y-Si compounds, indicating that introducing H atom into Y-Si system can effectively increase the superconducting transition temperature. Y₂SiH₁₇ exhibits a T_c of 35.8 K at 100 GPa. Spectral function and electron-phonon coupling calculations suggested that in YSi₂H₁₄ and Y₂SiH₁₇, in addition to the H-induced superconductivity from mid-frequency vibrations, low-frequency vibrations of Y also play a significant role for superconductivity.

Since the discovery of 4.2 K superconductivity in mercury, the search for room-temperature superconductivity has been a hot topic in the field of condensed matter physics. In recent years, scientists have discovered a series of high-temperature superconductivity, represented by covalent H₃S (superconducting transition temperature T_c=203 K) and ionic LaH₁₀ (T_c=250 K) and CaH₆ (T_c=215 K) under high pressures. These works have successively broken superconducting temperature records, opening a new era in search for room-temperature superconductivity in hydrogen-rich compounds. This paper focuses on the progress of theoretical prediction, experimental synthesis, and characterization in binary and ternary hydrogen-rich superconductors with high critical temperature under high pressure. Furthermore, it addresses the challenges and potential avenues in the quest for room-temperature superconductors in hydrogen-rich compounds.

The copper-based rare-earth perovskites La_1–xNd_xCuO₃(0≤x≤1) have been synthesized in the two-stage Walker-type high-pressure apparatus. The refined crystal structure results revealed that La_1–xNd_xCuO₃ (0≤x≤0.4) adopts a rhombohedral structure with the space group $R\overline 3 c $. When 0.5≤x≤0.7, a mixed phase with both $R\overline 3 c $ rhombohedral and Pnma orthorhombic structures was observed in the system. With a further increase in Nd³⁺ doping, the system exhibits a single Pnma orthorhombic phase when x=0.8, 0.9 and 1. A comprehensive structural phase diagram of La_1–xNd_xCuO₃ (0≤x≤1) was established in this study, providing a new material platform for investigating the magnetic properties, metal-insulator transitions, and other physical property evolutions in rare-earth 3d transition metal oxides.

We present a theoretical approach for predicting the electron configuration, polymorph, synthesis condition, and physical properties of complex magnetic double perovskite compounds. Our method is reasonable and computationally efficient, allowing us to identify an antiferromagnetic (AFM) metallic material, namely Mn₂FeOsO₆, with a high AFM Néel transition temperature (T_N). Through extensive analysis, we demonstrate that Mn₂FeOsO₆ possesses a high density of states near the Fermi level and an AFM configuration, resulting in a zero total magnetic moment. Our findings suggest that the expected T_N of Mn₂FeOsO₆ is as high as 680 K, representing a potential breakthrough in the field of spintronics. We have also constructed a sophisticated magnetic model for this material, and obtained a reasonably reliable magnetic excitation spectrum potentially comparable with neutron scattering spectra. This theoretical approach provides synthesis conditions that are consistent with many synthesized double perovskite compounds in experiments, and it holds promise for the prediction of other complex magnetic configurations. Our study may play a key role in the big data prediction of novel double perovskite materials.

In order to explore the influence of CO₂ and porous materials on methane explosion characteristics, the 100 mm×100 mm×1000 mm explosion pipeline was independently designed. The influence of porosity of different porous materials and CO₂ injection pressure on methane explosion flame structure, flame propagation velocity and explosion overpressure were examined. The results show that: the porous material has two opposite effects on flame wave attenuation and promotion. When the porosity of the porous material is 10 and 20 PPI, it fails to resist the explosion, but when the porosity is 40 PPI, the explosion resistance is evident. CO₂ jet pressure has a certain effect on explosion resistance. When the porous material is 10 and 20 PPI, the peak flame velocity decreases gradually with an increase in CO₂ jet pressure, the maximum attenuation rate is 13.64%, and the maximum attenuation rate of the peak explosion overpressure is 52.83%. According to the variations of flame velocity and pressure, the porosity of the porous material is 40 PPI, and the CO₂ jet pressure is 0.4 MPa, the explosion suppression effect is the optimal.

The electrical explosion of metal bridge foil is a key physical process in many fields, e.g. electric guns and slapper detonator. Due to the complexity of material properties, dynamic processes, and effects of geometric configurations, a large amount of earlier theoretical simulations used simplified physical models. In this paper, a three-dimensional electromagnetic-thermal-mechanical model was established. which was a full physical model describing the early behavior of explosive foil. The early thermal expansion process of the explosive foil under large current loading was simulated, and the evolution of magnetic field, current, temperature, expansion speed of the foil was analyzed. The phenomena of angular and linear current diffusions induced by the configuration and the resistivity were observed in the simulation. The temperature distribution in the bridge region obtained from the simulation is qualitatively consistent with experiment and simulation results of literature.