The hollow microsphere/aluminum alloy composites was fabricated by press infiltration. The dynamic compression behavior of the composites was investigated by using split Hopkinson pressure bar (SHPB). The microstructure of the specimen after compression was characterized by scanning electron microscopy, and the damage patterns of the hollow microsphere was primarily studied. A single-cell model of the composites was established, and the dynamic compression process of the single-cell was simulated by using the LS-DYNA explicit finite element software. With dynamic loading, mechanical behavior of hollow microsphere/aluminum alloy composites showed three typical stages: elastic deformation, plastic collapse and densification. With the increasing of the decrement, the hollow microsphere appeared cracks along the meridians, gradually transitioned into the fragmentation of the equator, and eventually collapsed.

In order to improve the quality and prolong the shelf-life of vegetables, the effect of high hydrostatic pressure on pasteurization and quality of vegetables was systematically analyzed and assessed by taking white turnip, lettuce and potato as experimental materials. The results were as follows: The bactericidal effect did not change significantly after treatment of 600 MPa for 5 min. The hardness and resilience of HHP-treated vegetables increased significantly, and Vc content of potato, lettuce and white turnip increased respectively by 49.4%, 17.0% and 23.3%, while ΔE decreased as compared to those with thermal treatment. Sensory evaluation showed that vegetables treated with high hydrostatic pressure were similar to fresh vegetables in color, smell, taste and shape. Therefore, high hydrostatic pressure technology can achieve ideal effects in sterilization, and maintain the quality of vegetables.

This paper describes the coupler reciprocity method and free-field reciprocity method used for standard hydrophones calibration in the frequency range of 20 Hz to 200 kHz at 10 MPa hydrostatic pressure, and the coupler reciprocity calibration facility working in the frequency from 20 Hz to 3.15 kHz and free-field reciprocity calibration facility working in the frequency from 3.15 kHz to 200 kHz was established on these methods. Standard hydrophones RHC14 and RHS30 were calibrated separately using these facilities, and their sensitivities at 10 MPa hydrostatic pressure was presented. Analyze of measurement uncertainties proved that the expand uncertainty (at k=2) of coupler reciprocity calibration facility was 0.5 dB, and free-field reciprocity calibration facility was 0.7 dB (below 100 kHz) or 0.9 dB (100 kHz to 200 kHz). The construction of these facilities and capabilities sets the test foundation for deep-diving underwater sound devices.

Voronoi method was adopted to establish the micro-geometry model of polycrystalline copper which can reflect the irregularities of grain geometric shape and grain boundaries. The Tie-Break model was used to reflect the binding characteristics of grain boundary. Then the grains deformation and thermal deposition behavior under explosive dynamic loading were studied from the microscopic view recur to LS-DYNA nonlinear finite element program. Finally, the possibility of grain refining was anslyzed by high pressure melting point theory and grain growth theory, and the analysis was proved qualitatively by experimental results. The results show that it is feasible to research grain and grain boundary deformation mechanisms as well as the heat deposition for the shock compressed polycrystalline copper by the numerical simulation method built in this work. Stress concentration is easy to form on the grain boundaries, plastic deformation and temperature rise on the grain boundaries are greater than those of the grain interior. The temperature rise caused by the macro-adiabatic compression and the micro-plastic deformation does not cause grain growth.

Electronic structures and optical properties of oxygen atom adsorbed on GaAs surface have been calculated by using the first-principle based on density functional theory. The results show that the presence of O shifts the energy band to the deep part, with impurity level composed of As 4p and Ga 4p and Tamm surface caused by the splitting of As 4s and Ga 4s appearing in the forbidden band. Adsorption of O changes the distribution of d state and sp state electrons. The existence of O improves the defects in lattice-periodicity and changes the transition of electrons, resulting in the change in optical properties.

A physical criterion of dynamic tensile fracture has been introduced, based on the knowledge of the micro-mechanism and the measurement of the damage evolution. The physical criterion has suggested two critical damage parameters, named as the critical void coalescence damage D_l and the critical fracturing damage D_f. These two parameters are associated with a damage function model and a percolation-softening function, by which the fracture process is characterized as that the damage slowly increases in a linear manner from the initial state (D=D₀) to the void linkage state (D=D_l), then changes to a nonlinear growth and rapidly approaches to the critical fracturing state (D=D_f), while a final step catastrophically leads to the complete fracture state (D=1.0). Experimental measurements and numerical simulations for both of the plate impact and the cylindrical tube have verified that these two parameters (D_l and D_f) physically constrain the dynamic tensile fracture and may be considered as the intrinsic material constant. Application of this physical criterion for the prediction of dynamic tensile fracture under intricate loading and for complex geometrical system has been discussed.

For investigating kinetic behavior of pressure induced phase transitions, it is the most expected to combine high time-resolved diagnostic probes with the precise compression techniques. In fact, an indirect way in large volume press is compare characterization results of recovered samples with their experienced conditions including pressure, temperature and time. As a typical example, relationship between p-T conditions and time for diamond nucleation in C-H-O system is discussed by previous experimental data, demonstrated that extending loading time under HP/HT is propitious to form high pressure stable phase. In contrast, some meta-stable phases, such as bulk amorphous sulfur, metallic glasses and amorphous polymers etc., were obtained by rapid compression process. The results indicated that many substances can show the kinetic features of phase transition in the scale of compression rate from 1 GPa to 1 TPa/s. The kinetic phase diagrams with three dimensions (pressure, temperature and time) could be established through both of the static or rapid compression experiments.

Academician JING Fu-Qian pioneered two new fields of shock wave physics research in China at the end of the 1980s, that are shock wave physics applied to the Earth science and to the Space science and technology, called go up to the sky and go into the Earth. Academician JING Fu-Qian led us to carry out the only one Major scientific project of high pressure Geosciences-Study on the physical properties under high temperature and high pressure for materials in the important boundaries of the Earth's interior, he also directed the research of hypervelocity impact and protection against space debris impact in China. The recent research advances of shock wave physics applied to the frontier and hot spots of the Earth sciences in China were introduced in great detail and reviewed, including (1) the phase stability, equation of state, sound velocities, and thermo-elasticity of the Earth's lower mantle dominant minerals (Mg, Fe)SiO₃ perovskite and MgO-FeO system;(2) the possible mineralogical composition of the lower mantle;(3) the high pressure melting curve of Fe and Fe-O-S system;(4) constrained the light element in the Earth's outer core from the equation of state, sound velocities of Fe-O-S system;(5) the possible mineralogical interpretations of the seismic velocity anomaly in the lower mantle and core-mantle boundary;(6) Near Earth Object impact hazard and defense response. The current problems were emphasized and the new research trends were prospected. The authors dedicated this paper to commemorate the 1st anniversary of Academician JING Fu-Qian passed away.

High pressure can cause rearrangement of atoms in microstructure, and arouses reconfigurations of electronic states, which often brings new materials and new properties. The rich and colorful new phenomena and properties in the typical molecule system have been observed under high pressure. Studies of these new phases and behaviors in typical molecular system under high pressure are very important and significative. Two types of substance, i.e.elementary crystals and small-molecule compounds, are investigated thoroughly on structures and properties under high pressure, and demonstrate various features. In the elementary crystals, such as pressure-induced phase transition and metallization in I₂ (solid iodine) and N₂ (polymeric nitrogen), and in the small-molecule compounds, such as the hydrogen-bond and halogen-bond interactions in crystalline iodoform and bromoform under high pressure, the effects from dihydrogen bonds in ammonia borane which determining the complex dynamics behavior of rotations of the NH₃ and BH₃ groups under high pressure, etc.are discussed deeply. The distinct behaviors of molecular dissociation, reconstruction of crystal structures, and pressure-induced metallization in the typical small-molecule system under high pressure are very different from the ones at ambient conditions. Exploration of the typical small-molecule crystals under high pressure provides an important way to discover the new structures, new materials and new physical phenomena and properties.

The theoretical calculation on thermal conductivity of explosive is still one problem. We presented our developed two calculation methods for thermal conductivity of explosive. The first one is based on atomic motion equation. We derived the formulations of thermal flux in system and thermal conductivity of system. It is suitable to calculate the thermal conductivity in different directions. The second one is based on the phonon-phonon dispersion model and Debye model. This method can effectively calculate the thermal conductivity under pressure. Using these two methods, we have calculated the thermal conductivity of HMX under pressure, and deeply analyzed the factors which affect the thermal conductivity of HMX.