Tin and lead beads are chosen to conduct the high velocity impact experiments with an explosive plane wave generator. The impact velocity is about 2 km/s. A metallurgic picture of the recovered specimen shows that there are four bands along the interfaces between tin and lead. The width across the bands is about 60~80 μm. The SEM examination discloses that these bands are the mass mixing regions of tin and lead. The dynamic diffusion coefficient of the experiments is 0.9 cm²/s, which is much higher than that at quasi-static case. A discrete element simulation (DEM) demonstrates the process and mechanisms of the observed mass mixing for Pb-Sn beads under shock loading at meso-scale qualitatively.

The extent and crystal structure of the solid solution based on Ca₂Pr₂Cu₅O₁₀ were studied by X-ray diffraction combined with Rietveld structure refinement. According to the principle of valence neutralization and the disappearing-phase method, in the Ca-rich region (i.e. Ca/Pr>1) the composition of solid solution can be expressed as the general stoichiometry Ca_2+xPr_2-xCu₅O₁₀, and in the Pr-rich region (i.e. Ca/Pr<1) as Ca_1.7Pr_2.2Cu₅O₁₀、Ca_1.4Pr_2.4Cu₅O₁₀, i.e., the solid solubility of the Ca₂Pr₂Cu₅O₁₀-based solid solution can be determined as from Ca_2.4Pr_1.6Cu₅O₁₀ to Ca_1.4Pr_2.4Cu₅O₁₀. The crystal structure of Ca₂Pr₂Cu₅O₁₀ based solid solution is an incommensurate phase based on the orthorhombic NaCuO₂-type subcell. The lattice parameters of Ca_2.4Pr_1.6Cu₅O₁₀ subcell are a₀=0.28246 (7) nm, b₀=0.63693 (1) nm, c₀=1.06794 (1) nm, and its orthorhombic superstructure is with a=5a₀, b=b₀, c=5c₀. The Ca_2.4Pr_1.6Cu₅O₁₀ structure is also determined by using a monoclinic supercell with space group P2₁/c, Z=4, a=5a₀, b=b₀, c=c₀/sinβ and β=104.79 ° or 136.60 °, V=5 a₀b₀ c₀. In the structure of the solid solution based on Ca₂Pr₂Cu₅O₁₀, the mutual substitution between Pr and Ca is possible in some bound. Furthermore, they are distributed disorderly in the structure.

The effect of preparation pressure on the structural, magnetic and electronic properties has been investigated for nanostructured bulk samples of La_2/3Sr_1/3MnO₃. The results show that the grain size decreases and magnetoresistance varies with preparation pressure growth. Low-field magnetoresistance weakens in the whole experimental temperature range when preparation pressure increases, which can mainly attribute to strong-link grain boundaries of samples under high preparation pressure. And high-field magnetoresistance gradually becomes stronger at T<200 K, however becomes weaker at T>200 K with the increase of preparation pressure, which can mainly due to the change of grain size caused by preparation pressure.

By solving the two-dimensional Euler equations coupled with the chemistry, a numerical simulation of transient detonation process induced by flame for H₂-O₂-N₂ mixture was performed, and a detailed chemical mechanism for H₂-O₂-N₂ system, which included 19 element reactions and 9 species, was involved. A splitting operator method was used to treat separately the hydrodynamical process and chemical process in the detonation simulation. The TVD scheme was used to capture the detonation wave and the Gear algorithm was used to solve the chemical reaction. The calculated results show that combustion rate of flame can be accelerated and lead to the occurrence of detonation when the initial mole fraction ratio of the mixture is H₂∶O₂∶N₂=0.4∶0.4∶0.2 and the initial nondimensional temperature is T/T₀=5.3, the detonation wave can be propagated steadily with the detonation velocity of 2300 m/s. The reflection of the detonation wave can be observed. In addition, the variations of species concentrations and temperature behind the detonation wave were also discussed in order to understand the inherent structure behind the detonation wave.

All spacecraft in low orbit are subject to hypervelocity impacts by meteoroids and space debris. These impacts can damage spacecraft flight-critical systems, which can in turn lead to catastrophic failure of the spacecraft. In order to ensure the astronauts safety and spacecraft normal operation, the design of meteoroids and space debris protection configuration become an important problem of spacecraft design. The numerical simulations of debris cloud produced by projectile hypervelocity impact on bumper at normal and oblique angles have been carried out using the SPH (smoothed particle hydrodynamics) technique of AUTODYN hydro-codes in this paper. The results using two and three-dimensional simulations are given. The effect of bumper thickness, projectile shape, impact velocity and material models etc. on debris cloud has been investigated. The simulation results are compared with experimental results, and the simulated debris cloud shapes and debris cloud characteristic points velocity are consistent very well with experimental results.

The mechanisms of solid cobalt diffusion, molten cobalt infiltration and two wave-like cobalt peaks movement through diamond layer during the sintering process were discussed theoretically according to the experiment data. Results show that the solid cobalt diffusion coefficient under 5.8 GPa and at 1300 ℃ is about 1.6×10^-7 cm²/s, which is almost the mean value between the solid cobalt diffusion coefficient (3×10^-10 cm²/s) at the same temperature under atmospheric pressure and the liquid cobalt diffusion coefficient (5×10^-5 cm²/s) under 5.8 GPa and at 1300℃. It also shows that the infiltration time of molten cobalt through diamond layer for diamond grain size 10 μm and 1 μm are about 0.5 s and 28 s respectively, and the moving velocity of the two wave-like cobalt peaks were about 50 μm/s and 100 μm/s, respectively.

The mixture is as a randomly distributed component grains in three-dimensional meshes. The shock compression behavior of mixtures is simulated numerically by using the 3D thermodynamics finite element method. We have studied the course of tendency to the thermodynamic equilibrium, the characteristic time of temperature equilibrium, the characteristic time of pressure equilibrium and the equilibrium state of mixture following the shock compression and found the relation between the characteristic time of temperature equilibrium and the square of the grain dimension of mixture and the linear relation between the characteristic time of pressure equilibrium and the grain dimension. The shock compression behaviors of some alloys are simulated numerically, and the results are compared with the fraction volume model of EOS, the superposition principle of the first shock Hugoniot, and the experimental results. Except for the shock temperature, the results are in good agreement with each other. The fraction volume model and the superposition principle cannot yield reasonable shock temperatures, but the numerical simulation method does.

The relation between the survivors of micro-organisms and the processing pressure and the pulse pressure processing was investigated in UHP treatment to watermelon juice. And species of baroduric bacteria were discriminated. Processing pressure is between the atmosphire pressure and 500 MPa, and the pressurized duration 10 min in this experiment. Results show that under the ambient temperature (30 ℃) and pressure equal to or above 400 MPa the number of natural microflora, yeast, mold and coliform bacteria meets the requirement of National Food Hygienic Standard of China. When the times of pulse pressure processing increases, the survivors of micro-organisms decreases. Gram positive bacteria are the main part, ≈70%, of the survived bacteria, and the rests are the Gram negative bacteria and molds.

We have studied the equation of state (EOS) of aluminium by using energy dispersive synchrotron radiation X-ray diffraction technique at room temperature under in situ pressures up to 21.5 GPa. The data were fitted to Murnaghan equation of state and gave the bulk modulus and its first order derivative of aluminum: B₀=(77±2) GPa, B₀′=4.8±0.3. We attributed the small deviation of our result from those in the literature to the nonhydrostatic effects caused by the pressure transmitting medium NaCl. Yet we have not found any convincing evidence for a phase transformation in the experimental pressure range.

As a pressure gauge, Ruby is the most common and wildly used mineral for determining pressure in DAC experiments, but it has difficulty in such an experiment that simultaneously contains high temperature and water. Quartz is a new mineral proposed recently as a pressure gauge and it can be used with the system containing water, however it is limited at the pressure p<2.0 GPa and the temperature T<600 ℃. On the other hand, equation of state (EOS) of material is much reliable for determining the pressure in the experimental studies with DAC, but it is inconvenient and limited by the condition of instrument. For example, EOS of water is useful if the system is aqueous solution and no mineral can be used as a pressure gauge in order to avoid any interaction. Therefore, comments and suggestions have been addressed in this manuscript.