There is a remarkable temperature gradient in the sample cell in the pulse transmission experimental setup on a multi-anvil high pressure apparatus. The elastic wave velocity was corrected by combination of experiment, theory analysis, and computation in terms of the experimental data on temperature distribution in the sample and the linear decrease of temperature dependence of elastic wave velocities in rocks at a given temperature range. The experimental v_P in amphibolite was corrected by this method and compared with the v_P without correction: the absolute correction value turned greater as the temperature increased; at 530 ℃, the greatest correction of velocities in the sample X and sample Y were up to -0.270 km/s and -0.118 km/s with the decreases of 3.3% and 1.5%, respectively. This method improves the accuracy of v_P measurement in high pressure and temperature experiments, which is useful to interpret geophysical data by combining the experimental results.

By statistical thermodynamics methods and CHEQ code, the concentrations of carbon in the system of graphite-water were calculated at 5.5~7.7 GPa and 1000~2900 K. Relation between the concentration of carbon in water and the pressure was mainly studied. Results could be summarised as follows: (1) At a fixed pressure, there is a definite down-limit and a up-limit of temperature, between them the concentration difference of graphite and diamond in water ΔX(C) is positive; (2) Under a definite pressure, there is a maximum of the concentration difference of graphite and diamond in water. Both of the maximum of ΔX(C) and the temperature, which make ΔX(C) maximum, increase with the increase of the pressure remarkably.

In this paper, the possibility of synthesizing the boron-carbon-nitride (B-C-N) compound by water catalyst has been investigated. The micro-crystal mixture of graphite and hexagonal boron nitride (hBN) was obtained by ball-milling. Under the temperature of 800~1500 ℃ and the pressure of 6.1 GPa, this mixture reacted with water. By XRD and XPS, we analyzed the reaction products of the mixture with water, and found that the recrystallizing graphite formed and the crystallinity of graphite increased gradually when temperature increased, but recrystallizing hexagonal boron nitride (hBN) and cubic boron nitride (cBN) were not found. When the ball-milling was not sufficient, the XRD spectra peak of the micro-crystal mixture of graphite and hexagonal boron nitride (hBN) had not been widened sufficiently. The crystal of graphite and cubic boron nitride (cBN) were found, but the B-C-N crystal was not found.

The propagation of shock-induced phase boundary in a material undergoing irreversible phase transition was studied theoretically using a model based on simple-mixture rule. It was found that along with the decay of the phase boundary, the functionally graded material (FGM) formed in the mixed-phase region. Such FGMs are composed of original phase and product phase, and the composition and physical properties are changing continuously with the coordinate without apparent macro-interfaces between two phases. The effect of stress boundary conditions of impact loading on the grade and range of the FGM region was investigated in detail with a numerical method. Finally, the possibility of producing FGMs with impact method was proposed and the limit of this method has been discussed.

The numerical simulation of the shock wave induced by intense proton beams were presented in this paper, the energy deposition process of the intense proton beams in Al were simulated by Monte Carlo method, and the coupled mechanical process induced by the energy deposition were simulated by use of one dimensional fluid-elastic-plastic model. Some results such as the energy deposition profile of the intense proton beams and the evolution of the induced shock wave were obtained.

Seeds of two rice (Oryza sativa L.) cultivars, Yuexiangzhan and Yuefengzhan, were soaked for 10 h, and then were treated by 75 MPa high hydrostatic pressure for 12 h. Germination rates decreased to 85.6% (Yuexiangzhan) and 83.4% (Yuefengzhan) relative to the untreated, and seedling rates were only 24.6% (Yuexiangzhan) and 21.9% (Yuefengzhan). Plant growth was inhibited in both treated cultivars during the early growth stage of seedling, but could exceed that of the contrast after sowing of 35 d. The seedlings of the treated and untreated were transplanted in the field after sowing of 35 d. Photosynthetic characteristics were compared between the treated and untreated during flag leaf development (55~130 d after sowing). The average values of net photosynthetic rate (P_n) and apparent quantum yield (AQY) in treated cultivars increased by 9.2% and 12.4% (Yuexiangzhan), 5.7% and 17.4% (Yuefengzhan), relative to the untreated, respectively. The total average photosynthetic pigment content was higher in both treated cultivars than their untreated during different growth stage. During leaf senescence, both F_v/F_m and pigment content decreased slowly or lately in two treated cultivars than the untreated. Consequently, the biomass and grain yield increased by 8%~27% and 7.6%~14% in both treated cultivars. Several mutated strains with different morphological and yield characteristics could be selected from treated rice plants. The results suggested that high hydrostatic pressure treatment is possible served as a new method of breeding in the future.

In this paper, the shear fracture performances of LY12 aluminum cylinder were studied under explosive loading. The recovered fragments showed shear characteristics. The fracture surface formed along the maximum shear stress curves. SEM images of the recovered fragments illustrate that the fracture surfaces have undergone friction. The adiabatic shear bands and microcracks all initiate near the inside wall and develop along the maximum shear stress curves to the outside wall of the cylinder. The histories of stress and strain from numerical calculations indicate the adiabatic shear bands initiate more easily near the inside of cylinder than in other zones, which corresponds to the results of metallographic analysis.

The temperature rise near explosive welding interface is caused by explosive adiabatic compression and abnormal deformation energy deposition. Through the calculation of temperature rise, the melting criterion was given, and the thickness of melted layer near explosive welding interface was estimated.

It is well known that Li₃N, Mg₃N₂ and Ca₃N₂ are catalysts for cBN synthesis under high temperature and high pressure. We discovered that they could also act as catalysts for hBN formation at high temperature and normal pressure. It is confirmed that, from a series comparative experiments, each of them has catalysts effect only on melting condition, the catalytic order for hBN formation is Li₃N>Mg₃N₂Ca₃N₂, which is similar to that for cBN synthesis. The suggestion that a catalyst for hBN formation may also be a catalyst for cBN synthesis may be reliable.

Diamond nucleation improved by negative bias-enhanced technology on Si (100) substrate has been investigated on a microwave plasma enhanced chemical vapor deposition (MPCVD) apparatus using a gas mixture of methane and hydrogen. The results show that the bias voltage has a significant effect on the uniformity of the nucleation density and the concentration of the methane mainly relevant to the nucleation time. There is an obvious brim effect of the nucleation when the size of the silicon substrate is less than that of the Mo substrate holder. The nucleation density of the side is higher than that of the center on the substrate when the bias voltage is lower than -150 V. The nucleation density of the side decrease significantly with the bias voltage when the bias voltage is lower than -150 V. There are nearly no nuclei on the side of silicon when the bias voltage is -200 V. This effect may be contributed to the electron emission of the diamond on Mo substrate holder. The concentration of the methane has little effect on the nucleation density at a fixed bias voltage. Increasing the methane concentration is useful for decreasing the nucleation time.