The high-pressure behavior of wurtzite AlN nanowires is studied up to 51.1 GPa by in situ angle dispersive X-ray diffraction using synchrotron radiation source and a diamond anvil cell. With increasing pressure up to 24.9 GPa, the wurtzite-to-rocksalt phase transition was observed. The rocksalt phase is quenched after a complete pressure release. The axial ratio c/a of the wurtzite AlN nanowires decreases linearly with increasing pressure. The unique wire-like structure in AlN nanowires results in the high pressure behavior being different from that of the bulk and nanocrystal AlN.

Thermodynamic and transport properties of CO₂-expanded methanol system and CO₂-expanded ethanol system, as well as the diffusivities of p-chloronitrobenzene/CO₂-expanded methanol system and benzonitrile/CO₂-expanded ethanol system were modeled with molecular dynamics simulation method. The density data obtained in CO₂-expanded methanol system are slightly higher than the experimental ones, while that achieved from CO₂-expanded ethanol system are very close to the experimental results. Simulation results show that the volume of methanol or ethanol solutions can be expanded significantly by CO₂. When the mole fraction of CO₂ reaches 50%, the volume swelling of the solution is 100%. In addition, the diffusion coefficients of CO₂, methanol, ethanol, p-chloronitrobenzene and benzonitrile were simulated, in which p-chloronitrobenzene and benzonitrile are similar to experimental data. Finally, viscosities of two expanded liquids are correlated by their diffusion coefficients, which is in agreement with the calculated results of modified Wilke-Chang equation.

The significance and difficulty of the multi-position measuring were analyzed when understanding and interpreting the wave signals measured in impact dynamic experiments. By combining the Lagrange inverse analysis with the Hopkinson pressure bar technique, a new method was proposed, which substantially resolves the problem of measuring simultaneously both stress wave and particle velocity at a Lagrange position in impact tests. When the particle velocity wave signals at n (n≥3) Lagrange positions are measured, by using this new method, the dynamic stress-strain curves at n Lagrange positions of specimen can be determined and interpreted. The feasibility and validity of this new method was consistently confirmed by numerical tests for two viscoelastic materials (PMMA and cement mortar).

In an ultra-high pressure water jet cutting system, the micro jewel nozzle has important influences on the machining efficiency. Cavitation inside the jewel orifice affects the jet formation directly and is a crucial reason for the nozzle wear. By simulating the cavitation flow in the orifice at pressure within 400 MPa, the jet formation process in the nozzle was expounded. The influence of pressure, the aspect ratio and the inlet shape of orifice on the cavitation and jet were also analyzed. At the same time, an experiment was carried out to study the nozzle wear. The results show that the cavitation region in orifice reduces along the nozzle axis with the increasing of the aspect ratio. Moreover, the cavitation region can reach the nozzle outlet when the aspect ratio is smaller than a certain value. At this condition, the jet initial diameter is smaller than the orifice diameter and increases with the increase of pressure. The orifice inlet with a streamline design can effectively restrict the cavitation development. The wear in the jewel orifice inlet due to the cavitation and water erosion is much more severe than in the outlet and is more serious under higher operating pressure. Accordingly, it is useful to select a appropriate aspect ratio for reducing the erosion in the nozzle.

Medium-chain fatty acids (MCFA) nano-liposome was prepared and characterized by means of high pressure microfluidization (HPM), sonication and microfiltration, respectively. The average diameter, encapsulated efficiency and stability were investigated after treatment with different pressures and passes number. The results indicated that MCFA liposome prepared by HPM exhibited the smallest average diameter, the largest encapsulated efficiency and the best stability. The smallest average diameter of MCFA liposome could be achieved after a treatment of 6 passes at 120 MPa, with a value of (73.9±10.2) nm, while the encapsulated efficiency was (52.20±9.57)%. The largest encapsulated efficiency of (70.64±11.25)% and loaded efficiency of (9.42±0.83)% were obtained when treated 4 passes at 120 MPa, with an average diameter value of (78.9±21.5) nm. After being treated 4 passes, MCFA liposome exhibited the best stability, with a coefficient value of 0.999 0±3.695 1.

Aluminum bronze was treated at 5 GPa and 750 ℃ for 15 min, after that its electric conductivity, thermal diffusion coefficient, heat capacity, and thermal conductivity between 25 and 600 ℃ were measured. Combining these data with the microstructure images, the effects of high pressure heat treatment on the thermal physical properties of aluminum bronze were investigated. The results showed that high pressure heat treatment can increase the thermal diffusion coefficient and decrease the heat capacity of aluminum bronze. Furthermore, the thermal conductivity of aluminum bronze after high pressure heat treatment increases with increasing temperature until 400 ℃, and then starts to decrease. Analysis shows that this is because the high pressure heat treatment makes the microstructures of aluminum bronze alloy change.

To verify the three current international views on the generating condition of over-detonation during gaseous deflagration-to-detonation transition (DDT), the DDT process of gaseous hydrogen-oxygen mixture was experimentally studied by using pressure sensors. The whole pressure histories of gaseous DDT from detonation to DDT and then to stable detonation were obtained. The experimental results showed that the generation of DDT requires certain physico-chemical conditions, and for certain initial pressure conditions, the transformation time (or distance) decreases firstly and then increases with increasing concentration of hydrogen. The peak pressure in over-detonation is about 1.5~2 times as much as that in the stable detonation.

Using Lagrange analysis method for high explosives, a simple detonation reaction rate model of explosive PBX-9502 was proposed. With this model, the longitudinal structure of detonation reaction zone of explosive PBX-9502 was obtained. By Comparing with experimental results and calculated results of ignition and growth model, it shows that current model has good feasibility and validity for the longitudinal structure of detonation reaction zone of PBX-9502.

The blast shock wave pressure and the bubble pulse period of RS211, HL-1, HL-2 and TNT explosives were measured, and then the peak pressure, shock wave impulse, shock wave energy and bubble energy were obtained. The experimental results showed that in the studied range, the shock wave energies and the bubble energies of the three aluminized explosives were about 1.20~1.35 and 1.50~2.30 times more than TNT explosive, respectively. The analysis results indicated that the aluminum powder added to explosives can enhance underwater explosion power of the explosives.

Numerical simulations of tungsten long rod penetrating into confined ceramic target was carried out by inserting the constitutive models of ceramic and metal in the SPH/FEM coupling method. The penetration pattern was reproduced and the property of anti-penetration of ceramic targets was discussed. The computational results for different impact velocities were compared with the experiments. The penetration depths of computations are in good agreement with the experiments and so that the coupling method is validated.