A series of plate impact experiments were conducted for soda-lime glass specimens on a one-stage gas gun in order to investigate the so-called failure wave phenomena under different impact velocities. In each shot, four pieces of specimens with different thicknesses are impacted simultaneously and the longitudinal stress histories at the backing surfaces of each of them are measured by manganin piezo-resistive stress sensors. Hence, the failure wave trajectory under a certain dynamic loading can be obtained by only one shot. Then the formation and propagation of the failure wave under different shock conditions can be obtained by changing impact velocities. The results show that the delay time for the failure wave to initiate decreases with the magnitude of impact loads, while correspondingly the failure wave velocity increases. In the end, the elastic statistical crack model is applied to describe the fracture mechanism of the soda-lime glass under shock loading and several plate impacts under different conditions are simulated by the LS-DYNA finite element program. The simulated results of the transverse stress and free surface particle velocity histories can be used to describe the failure wave phenomenon, and the trajectories obtained by simulation are compatible with experimental measurements.

A newly designed configuration based on an electric gun (namely two-stage electric gun) was used to launch metallic flyer, and dimension of ∅10 mm×0.5 mm, ∅10 mm×0.3 mm aluminum flyers can be accelerated to 300 m/s and 500 m/s, respectively. Using the two-stage electric gun, dynamic response of Zr-based amorphous alloy was investigated under planar impact and good results were obtained. This work extended the capability of electric gun to contain wider range of planer flyer velocity (0.1-10 km/s) and loading strain rates (10⁵-10⁶ s^-1), and it may be helpful to planer-impact experiments.

Material experiments were performed to identify dynamic constitutive model parameters for steel core of 7.62 mm×39 mm bullets and N-1 high-strength steel. Highly detailed FE model of the projectile and steel target plate was built up. The J-C fracture rule for the target plate was modified and implemented with LS-DYNA. The process of N-1 steel being impacted by steel core projectile was simulated with the modified fracture rule. Adiabatic shear behavior and the size of plug from the target plate are predicted accurately. Ballistic limit velocity simulation agrees well with experimental result. In this way, the unreasonable tensile failure within steel target and the underestimation of plug size predicted based on original J-C fracture rule are overcome.

The three-dimensional deformation and instability of high-density spherical bubble induced by incident shock wave and its reflected wave were studied numerically by using large eddy simulation method. The computational model was validated by the experimental results. The emphasis was placed on the interaction of reflected shock wave with the deformed high-density bubble. The formation and three-dimensional instability of vortex rings were discussed. The results show that the high-density spherical bubble can form the vortex rings with the different rotating directions along the streamwise direction induced by incident and reflected shock waves due to the baroclinic effect. The vortex rings induced by reflected shock wave have the less strength, and therefore are more likely unstable, and even can form a complicated small-scale structure dominated by the streamwise vortices.

In order to protect spacecraft against space debris impacts, it is a feasible direction to develop the shield with high strength fiber materials. The damage analysis of hypervelocity impact on high strength fiber woven is a key issue in the design of the space debris shielding, and the main content in the analysis of the dynamic behavior of materials in the hyper pressure condition. Woven of basalt fiber is one of the high strength ceramic materials concerned in recent years. The aim of this study was to study the residual velocity of aluminum projectiles at hypervelocity impact on woven of basalt-fibers. High velocity impact tests were carried out by the two-stage light gas gun facilities. The law of the velocity loss was researched according to the X-rays imaging of the projectile fragments. The residual velocity equations of aluminum projectiles were fitted from the hypervelocity impact experimental data. The study of the residual velocity equations is beneficial to the analysis of impact energy consumption of woven of basalt-fibers to aluminum projectiles.

The inactivation kinetics of β-glucosidase in blackberry were investigated at high hydrostatic pressure (300-600 MPa) combined with moderate temperature (35-55 ℃). Analysis of the obtained kinetic data revealed a dual-effect of combined pressure-temperature inactivation: the first one, designated as an instantaneous pressure kill value (IPK), which depended on temperatures and pressures, but was independent of treatment time; and the second one, a labile and stable fraction of β-glucosidase from blackberry are present and the inactivation kinetics of β-glucosidase by high hydrostatic pressure combined with temperatures are adequately described by the two-fraction model. The kinetic rate constants K_L and K_S of labile and stable fractions are 2.777 and 0.047 min^-1, and the decimal reduction times D_L and D_S are 0.83 and 49.1 min at 400 MPa and 55 ℃. T_Z representing the needs of temperature increase for a 90% reduction of the D value and the activation energy E_a of the labile fraction at 400 MPa are 23.36 ℃ and 81.95 kJ/mol, p_Z representing the needs of pressure increase for a 90% reduction of the D value and the activation volume V_a at 45 ℃ are 1 111 MPa and -5.02 cm³/mol.

The underwater explosion near field shock waves propagation process of aluminized explosive HLZY-1 were observed by SJZ-30 and GSJ-15 high speed streak cameras. The explosives were initiated at the end surface, the side and the center. The streak curves of near field shock waves were digitized, and the pressure attenuation curves of shock wave were achieved. The experimental results indicate that the initiation mode has great effect on the original magnitude and the attenuation of near field shock waves peak pressure, which can provide some reference for design of warheads of underwater weapon and the evaluation of destroy efficiency.

Axisymmetric unit cell model calculations are used to study void growth in a material containing a periodic array of spherical voids under different loading rate rates. Numerical results show that: (1) Micro-inertia is found to have a strong stabilizing effect on void growth process; (2) The growth rate of void increases with the square root of mean stress; (3) Accounting for micro-inertia effect on void growth and percolation stress relaxation during the void-coalescence process, a simple dynamic damage evolution model is proposed for elastic-rigid-perfectly plastic materials; (4) By using of the proposed model the spall tests on copper under different impact velocities are simulated, and the numerical predictions are in good agreement with the experimental measurements, verifying the model applicability.

The minimum ignition energy is one of the important properties to estimate the fatalness of combustible gases. To get a theoretical value of minimum ignition, a physical model of spark ignition of the combustible gases was established, and a minimum ignition energy prediction method of combustible mixtures through a numerical analysis was given. The critical temperature and minimum ignition energy of methane-air mixture during spark ignition process were obtained. The results shows that MIE of methane-air has a U-shaped relationship to concentrations, and the MIE of premixed gas under concentration of 8.5% is 0.39 mJ, which agrees well with the experimental value.

Cr or Ti is coated on diamond surface by magnetron sputtering, and diamond with active metal coating/copper composite materials is sintered under high temperature and high pressure. The experimental results show that the introduction of active metals enhances the bond strength between diamond and copper, reduces the thermal boundary resistance and improves the thermal conductivity of diamond/copper composite materials. In addition, the experiments indicate that the thermalconductivity of the composites decreases with increasing diamond content and the reducing grain size of diamond. This phenomenon is attributed to the thermal boundary-resistance. The thermal conductivity of diamond/copper composite materials can be increased by increasing the grain size of diamond and improving the interface of diamond and copper.

Concrete is a widely used composite. The study of dynamic performance and anti-penetration effects on concrete is dependent on the numerical simulation, and the HJC model is often used in numerical simulations. On the basis of introduction about HJC model, parameter sensitivity analysis on HJC model by LS-DYNA numerical simulations is studied in the paper. There are five parameters (f_c, p_lock, A, B and N) are sensitive. According to the sensitivity parameters, it can improve the accuracy and quality of numerical simulation and the reasonable test methods and arrangements for testing chosen.

Using a two-stage light gas gun and shock recovery technique, a series of experiments up to 40-65 GPa were carried out on the nitrogen-rich material of precursor g-C₃N₄. The powder X-ray diffractions (XRD) of recovered samples showed that the precursor g-C₃N₄ was stable under 51 GPa pressure, while only a new crystalline phase β-C₃N₄ was obtained during 51-65 GPa pressure. The results confirm that β-C₃N₄ can be synthesized directly from precursor g-C₃N₄. This paper is significant for the study of synthesizing pure superhard carbon nitrides.

In some types of plasma, there did not exist an electrode or reference point. The electrode or reference point was needed when applying a bias voltage to a Langmuir probe. To acquire the characteristic parameters of transient plasma generated by hypervelocity impact, diagnostic system was established. The new electrostatic probe diagnostic system utilizing the double-Langmuir probe was given, in which no voltage and frequency sweep was required. This method can measure electron temperature and electron density as a function of time. This new instrument was based on a double-channel circuit, the current and voltage spectra were obtained from the probe synchronously by a digital oscilloscope. The aim of this work was to apply the double-Langmuir probe diagnostic system to time-dependent plasmas generated by 2024-T4 aluminum projectile hypervelocity impact 2024-T4 aluminum target.

The quasi-static and dynamic compression tests for Hf_44.5Cu₂₇Ni_13.5Ti₅Al₁₀ metallic glass were done by MTS810 and split Hopkinson pressure bar (SHPB) in the range of strain rate of 10^—4-10³ s^—1. The compressive stress-strain curves were obtained under varied strain rate and the fracture morphologies were studied by scanning electron microscopy. The experimental results show that the Hf_44.5Cu₂₇Ni_13.5Ti₅Al₁₀ metallic glsaa does not have the strain rate sensitivity under quasi-static compression. The dimple structure and periodic corrugations with about 60 nm spacing can be observed at the fracture surfaces which consist of radical zone and fan-shaped zone. Under dynamic compression, the yield strength rapidly declines with rise of strain rate, the metallic glass has the strain rate sensitivity. The fracture surfaces show floccule structure with vein-like patterns. Further observation reveals that dynamic compression fracture surfaces exist three fracture morphology: branch-like patterns, vein-like patterns and molten agglomerates.

A phase transition concerning lithium aluminate oxide (LiAl₅O₈) was observed. High pressure synchrotron radiation X-ray diffraction was used to explore its structure in a diamond anvil cell up to 47.0 GPa. We found the two phases are coexisted over a very large pressure range in the experiments. According to the analysis on the dynamic change of diffraction peaks with the increasing of pressure and the data reduction using indexed program, a new high-pressure phase of LiAl₅O₈ was identified at pressure below 45.0 GPa. This new phase has potentially a orthorhombic structure with a=0.995 9 nm, b=0.644 7 nm, c=0.333 4 nm and the space group of Pmm2.

As a novel non-thermal food processing technology, high hydrostatic pressure (HHP) is showing broad application in food industry. Compared to traditional technologies, this technology exhibits significant advantages in the retention of food quality, inactivation of microorganisms and enzymes. In this review, based on the comprehensive analysis, regulation of sub-lethal cells' membrane, genetic and structural components, metabolism under HHP treatment and a majority of sub-lethal food microorganisms general responses when exposed to some stresses are reviewed, and the stress response of sub-lethal food microorganisms exposed to HHP is discussed in this paper.

Using detonation-driven flyer, the samples of C₆₀ were shock loaded. For toluene extraction, the soot was examined by high performance liquid chromatography (HPLC). The results showed that most of C₆₀ was decomposed, a small part was changed into polymer, high fullerene, endohedral and other carbon cluster under shock wave high temperature high pressure. Under the shock waves of different intensity, the influence of the temperature and pressure on the decomposition and polymerization of C₆₀ were studied. The destruction mechanism of C₆₀ and the formation of the polymer of C₆₀ were also discussed.

In-situ high-pressure Raman study of the gypsum was carried out from 0 to 35 GPa with a diamond anvil cell (DAC). The authors determined the pressure dependences of the Raman bands of gypsum. A new Raman peak 1 012 cm^-1 in the stretching vibration of range is found at pressure of about 4.5 GPa, and its intensity is shown to strengthen with increasing pressure. So we can determine the occurrence of pressure-induced phase transition near 4.5 GPa.