A numerical simulation method for calculation of the three-stage light-gas gun impacts on launch flier to hypervelocity is presented. Based on multi-fluid volume of fraction (VOF) and parabolic piecewise method (PPM), a multi-fluid parabolic piecewise method (MFPPM) shock wave physics code is developed to calculate the experimental hypervelocity launchers. To verify and validate our code of MFPPM, some experimental hypervelocity launchers from Sandia National Laboratories are simulated, and the numerical results of flier velocity are excellent in agreement with that experiment (the maximal relative error is 1.07%). Experiment and simulation results of our experiment on the three-stage light-gas gun are given (the maximal relative error is 1.04%). To satisfy well of the high-pressure equation of state (EOS) data measurement, an improved design model from the computation is presented.

PbMoO₄, with high acousto-optic figure of merit, low acoustic loss and nicer acoustic impedance matching, has received much attention because of applications as acousto-optic deflector, modulator, adjustable filter, suface acoustic wave devices and great potential to act as an effective low-temperature scintillator for nuclear instrumental applications. In this study, in-situ Raman spectrum of PbMoO₄ was measured in a diamond anvil cell (DAC). The electrical conductivity measurement of PbMoO₄ was performed at different pressure and temperature. All Raman peaks disappeared at 12.5 GPa, which indicated that the PbMoO₄ experienced gradually the crystal to amorphous transition between 10.8 GPa and 12.5 GPa. Upon decompresstion from 26.5 GPa to 9.4 GPa a broad Raman peak occurred at a low frequency, while the peak of 858 cm^-1 occured at 2.4 GPa again, thus suggesting that the PbMoO₄ crystal was gradually recovered from the amorphous state. Above 10.8 GPa, the electrical conductivity of PbMoO₄ increased obviously with increasing temperature and pressure.

Using argon as a pressure medium, the phase transitions of monoclinic-structured ZrO₂ under high-pressure and high-temperature have been investigated by means of in-situ Raman spectra method and a laser-heated diamond anvil cell (DAC). At room temperature, the baddeleyite-type ZrO₂ begins to transform to a new phase at 3.4 GPa, Raman bands from the new phase become prominent at 10.4 GPa, and this new high-pressure structure retains up to 15.3 GPa, the highest pressure before heated. The new phase has been identified as Pbca phase. Raman spectrum of Pbca phase is presented for the first time based on our experiments. At pressure of 15.3 GPa the Pbca phase was heated by YAG laser to about 1 000~1 500 ℃, and then it transforms to a PbCl₂ phase. This phase is stable up to 23 GPa, the highest pressure in this study.

The Einstein model to consider thermal effect in universal equations of state (UEOS) is modified. It is proposed that the zero-point vibration term should be deleted in a thermal UEOS, and the parameters can not be directly taken as experimental data at a reference temperature, V_R, B_R, B′_R and , but their values at absolute zero temperature, V₀, B₀, B′₀ and . An approach is proposed to solve V₀, B₀, B′₀ and from V_R, B_R, B′_R and . The approaches are applied to three typical universal EOSs, including the Baonza, mMNH and Vinet EOSs. The numerical results show that the solved values of parameters are almost identical for different EOSs. And the thermo-physical properties predicted through different EOSs are almost identical at zero and low-pressure conditions, once the same approach and input experimental data are used to solve parameters. It is concluded that the prediction of thermo-physical properties at zero and low-pressure conditions cannot be taken as the criteria to judge the applicability of a universal EOS.

Using synchrotron radiation and diamond anvil cell (DAC) in high pressure research station of Beijing Synchrotron Radiation Facility (BSRF), energy dispersive X-ray powder diffraction (EDXD) of the natural enstatite collected from Damapin in Hebei Province, have been in situ measured under room temperature and high pressure (0~31.64 GPa) conditions. Then the unit-cell parameters of sample and their changes versus pressure have been acquired using the UnitCell software. Furthermore, basing on Murnaghan equation of state (EOS), bulk modulus K_T(0)=172 GPa, compression coefficient, and p-V equation of state of natural enstatite have been obtained. The experiment data show that compression coefficient have distinct anisotropy for the three crystallographic axis. This result is consistent with the anisotropy of elastic velocity of orthopyroxene.

Phase evolution (PH) of Zr₄₁Ti₁₄Cu_12.5Ni₁₀Be_22.5 bulk metallic glass (BMG) prepared by shock-wave quenching has been studied under high-temperature and high-pressure using in situ synchrotron radiation energy-dispersive X-ray diffraction. The results show that the primarily precipitated phase is Zr₂Be₁₇ at applied pressures, but the subsequent PH processes are different. The crystallization temperature increases with pressure, but with a sudden drop at about 6.0 GPa. Compared with experimental results of the BMG prepared by water quenching, it can be concluded that crystallization temperature of the BMGs prepared by shock-wave quenching and water quenching all drop at the same pressure region, at which their PHs are different from those of other pressures. The different PHs and the drop of crystallization temperature may be attributed to that the BMG possesses different atomic configuration at different pressures.

Silicone rubber is a macromolecule polymer, and can suffer a large deformation. The silicone rubber specimens are tested at a series of strain rates by modified Split Hopkinson Pressure Bar (SHPB) techniques. Based on the experimental data, a constitutive model of the silicone rubber is built up based on Ogden strain energy functions. An interesting phenomenon-localized damage cycle, so called lag circle-shows up in the tested specimen under high strain-rates loading. The diameters of the damage cycle are associated with strain-rate and specimen's size. A formulation about the relations between the diameter and the strain-rate, specimen's size is presented.

Hexagonal boron carbonitrogen (h-BCN) crystal was synthesized from the mixture of boron powder and CNH compound prepared by pyrolysis of Melamine (C₃H₃N₃) under high temperature (1 400~1 500 ℃) and high pressure (5.0~5.5 GPa). X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to determine the product chemical composition and characterization. The results show that the product has composition of B_0.18C_0.66N_0.16(near BC₄N) and atomic-level hybrid. X-ray diffraction analysis indicates that the powder has hexagonal network structure. Scanning electron microscopy result suggests that h-BCN crystal morphology are mainly hexagonal flaky and the diameter is about 1 μm, thickness 200 nm.

The structural, elastic, electronic and optical properties of CdO under high pressure were studied by plane wave pseudo-potential method which based on the density functional theory. The generalized gradient approximation and local density approximation were used to describe the exchange-correlation potential. Comparing the lattice constants and bulk modules between experimental and computational, we can find the calculated results by local density approximation are well agreement with the experimental values. Under high pressure, the conduction bands of two structures have a shift tendency to higher energy, and the valence bands have a shift tendency to lower energy. We analyze the optical properties about the two structures associate with the partial density of states and the shifting of energy levels under high pressure.

Pure titanate nanotubes and titanate nanotubes doped with Eu³⁺ ions were synthesized by hydrothermal method. In this process, the preparation of nanotubes is synchronously finished by doping with Eu³⁺ ions. The morphology, structure, thermal stability and luminescence property of titanate nanotubes were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), and photoluminescence instrument. The results show that the method is simple, stable and high-yield. The structure of the nanotube could be approximately indexed by (H, Na)₂Ti₃O₇ or (H, Na)₂(Ti, Eu)₃O₇. Treatment of high temperature will bring into big changes to structures of titanate nanotubes. When the calcine temperature is higher than 450 ℃, tubulous structure of titanate nanotube was destroyed and transformed into structure of anatase phase. Sample of TNT-Eu shows strong luminescence property. There exist three peaks (393.5 nm, 593 nm, 614 nm) in its luminescence spectrum which are associated to ⁵D₀-⁷F₁ and ⁵D₀-⁷F₂ Eu³⁺ electronic transition respectively.