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.

Two different W interlay/substrate bonding interfaces for the adhesion of diamond film deposited on WC-Co substrate were investigated using bias enhancing nucleation method, in microwave plasma enhanced chemical vapor deposition (MWCVD) device. The results indicate that hydrogen plasma decarburization, W interlayer sputtering, recarburization with negative biasing induce chemical reaction bonding interface formed between the W interlayer and the substrate. Recarburized W interlayer in the initial diamond deposition strongly adhere to WC grains on the surface of WC-Co substrate, and consequently improved the adhesion of diamond film on WC-Co substrate. This pretreatment improved the adhesion of diamond film more obvious, compared with sputtering W interlayer directly on the substrate, in which physical bonding interlayer formed. Carburization with high negative biasing can improve the roughness of the substrate surface, and consequently improve the effect of mechanical interlock. The nucleation density was increased by negative biasing and therefore improved the contact area between the diamond film and the substrate, consequently improved the adhesion of diamond film on WC-Co substrate.

Yb film sensor was fabricated by vacuum evaporation technique, and its performance has been studied under the longitudinal quasi-static loading in the range of 1 GPa. The comparison of two group Yb film sensors, one is unheated treatment and the other is heat treatment at 300 ℃ for 1 h in vacuum, indicates that the piezoresistance coefficient of the heated film is larger than not only the unheated, but also the Yb foils. With the analyses of SEM and electric performance, it is discovered that heat treatment helps to grow crystal, decrease the film resistivity and improve the piezoresistance coefficient. XRD analysis reveals that pressure may promote the growth of Yb crystals. Also, after treatment by pressure (≈1 GPa) Yb film sensors are easy to fabricate and have stable performance, which may have extensive usage in industry.

During the launch of hypervelocity projectile in the two-stage light gas gun, the remanent gas in target chamber and the pushing gas that leaks through the projectile might disturb the physical measurement of target sample. In this paper quartz gauges were used to detect whether the influence of such gases is in existence and how much it is. Our results show that the precursor gas exists indeed accompanied with the shoot of two-stage light gas gun, but its pressure is only about 10^-2 GPa in amplitude and could not produce obvious influence to the usual high pressure experiments.

The novel superconducting homologous series CuBa₂Ca_n-1Cu_nO_2n+2+δ (i.e., Cu-12(n-1)n) have been introduced. The compounds can be synthesized only under high pressure high temperature so far. The physical properties of Cu-12(n-1)n are briefly compared with other high T_c superconductors, while the advantages of the Cu-12(n-1)n superconductors in terms of simple composition, higher T_c and better high temperature high magnetic field properties are stressed.