The thermoelectric properties of PbTe nanoparticles were studied from ambient pressure to 0.8 GPa by using self-built set-up. The electrical conductivity increased while Seebeck coefficient decreased with loading pressure and these properties can be recovered after pressure released. Moreover, Seebeck coefficient is extremely high, up to 565 μV/K at ambient pressure. At 0.8 GPa, the electrical conductivity enhances four times, the power factor adds three times and Seebeck coefficient is only reduced by 20% comparing with those at ambient pressure. These results indicate that high pressure can improve the thermoelectric properties of PbTe nanoparticle. The contracted Femi-energy is also calculated based on the First Principle under high pressure from 0.4 to 4.0 GPa. The calculated values agree well with experimental data.

Dynamic Brazilian test of plastic-bonded explosives was investigated by split Hopkinson pressure bar (SHPB). The tensile strengths of three PBXs were acquired under different strain rates. The evolution of crack on sample surface was captured using high-speed camera. The strain field was calculated by digital speckle correlation method before samples occured to crack. The simulation on dynamic Brazilian test was performed using discrete element method, and the simulation model considering meso-structure was acquired. The simulation results show the produce and evolution process of damage and crack, and the simulation results are in accordance with the experimental results.

A loading test by explosive rods to simulate mechanical effects of pulsed X-ray was numerically simulated by fluid-structure interaction method. The 2-D numerical model including a cylindrical shell, two layers of rubbers, nineteen explosive rods and a layer of air was built. Therein, the two rubber materials were described by Ogden hyperelastic models, the explosive rods and their explosion product were described by High Explosive Burn model and JWL equation of state, and the air was described by polynomial equation of state. The numerical simulation was performed by the multi-material ALE method. The physical images, load transmission and structural responses were obtained. The results show that, in the loading test of 265 mm cylindrical shell by 19 explosive rods to simulate a cosine-distributed load induced by X-ray, the stress responses at typical locations are basically equivalent. Furthermore, the additive two rubber layers can affect the response characteristics of the shells, and tightly glued interactions can distort the structural responses of shells with small mass and/or low stiffness.

Steel plates are widely used to construct resistant structures, and a lot of literature report on the ballistic resistance of metallic monolithic target. However, few reports can be found for double-layered target (DLT), especially the one with large gap space. Experimental study was conducted on the DLTs of both in contact (I-DLT) and with 200 mm gap space (S-DLT) by using a gas gun to fire blunt projectiles. Each DLT was made of two A3 steel plates with the thickness of 5 mm. From the experiments, initial-residual velocity curves were obtained. The experimental observations are as follows. Firstly, both configurations of DLT suffer from shear plugging. Secondly, the ballistic limit of I-DLT is 1.92 times of that of 5 mm thick monolithic target. Thirdly, the ballistic resistance of S-DLT yield to large divergence. The large divergence, according to the high speed photograph and the recovered targets, is caused by the two classical different trajectory statuses of the projectile after perforation of the first plate. Fourthly, there are two ballistic limits for S-DLT. Finally, the ballistic limit of I-DLT is close to or greater than that of S-DLT. Parallel numerical simulations were conducted by ABAQUS/EXPLICIT, and the experimental phenomena and results were well predicted.

The initial yield behavior of Alporas closed-cell aluminium foams with relative density 8.5% under biaxial loading has been experimentally investigated using the Arcan apparatus and the universal testing machine (INSTRON 5544). The experimental yield surfaces measured from biaxial experiments are compared with various proposed phenomenological yield surface models. The comparison result indicates that the experimental data are consistent with both Miller and Deshpande and Fleck criteria. Biaxial experiments have been carried out on aluminium foams at various loading velocities to study the effect of strain rate on the initial yield surface. The results showed that the initial yield stresses of Alporas closed-cell aluminium foams are not sensitive to the equivalent strain rate ranged from 7.0×10^-3 s^-1 to 1.0×10^-1 s^-1.

According to characteristic of secondary debris, initial models of secondary debris are built. The models of secondary debris are classified as three patterns. The first patten is that the projectile is not fragmentated. The second patten is that the projectile is not entirely fragmentated. The third patten is that the projectile is entirely fragmentated. The secondary debris deceleration process is analyzed based on hydrodynamics theory and gas-solid two phase flow theory. The computational model of secondary debris deceleration is built. The computational results are consistent with numerical results very well. The model of secondary debris deceleration is validated.

We synthesized La_0.3Sr_0.7CrO₃ Mott compound by using high pressure and high temperature sintering method; and studied the crystal structure and magnetic properties. It is shown that La_0.3Sr_0.7CrO₃ adopts a cubic perovskite structure at room temperature. Above 170 K La_0.3Sr_0.7CrO₃ is paramagnetism with the χ(T) curve being fitted by Curie-Weiss law, while a spin glass transition was found in La_0.3Sr_0.7CrO₃ below 20.7 K.

Blowout is one of the most serious accidents of gas wells during drilling. To investigate leakage and dispersion of gas blowout and to provide scientific guidance for on-site emergency response, it is necessary to identify what model should be used to describe the leakage source. Leakage source model of gas blowout was theoretically analyzed by fluid dynamics and aerodynamics, and was also numerically demonstrated by computational fluid dynamics. Distributions of temperature, static pressure and Mach number were obtained from simulation based on theoretical analysis. These numerical results agree well with both theoretical results and related experimental results done by other researchers. The present study shows that leakage source of gas blowout during drilling stage can be characterized by model of choked flow and gas blowout can be recognized as under-expanded jet flow.

Using LS-DYNA simulation software, we studied the relationship of the EFP's damaging ability with the penetration incidence angle of explosively formed projectile (EFP). It was found that, with the incidence angle changing from 0° to 40°, the depth of vertical penetration of EFP reduced 34.2%, and the pore size of openings increased 18.2%. During the penetration, the head velocity of EFP changed as lines with time, and with the incidence angle increasing, the head velocity of EFP decreased more quickly. At first, the depth of vertical penetration of EFP changed as lines with time, then it showed slow upward trend. The relationship between penetration parameters and time was consistent under different penetration incidence angles. Based on 0° penetration theory of EFP and oblique penetration theory of rod projectile, according to fitting curve of simulation, the correction formula of depth of vertical penetration of EFP and angle was obtained.

According to the theries of explosion mechanics and rock fracture dynamics mechanics, we found that the slits location shear stress of the complex ligamented charge holders is about 1.59 times of that of the conventional ligamented charge holders. The finite element software ANSYS10.0/LS-DYNA was employed to numerically compare the blasting effects of three kinds of seam cartridge, and it was found that the blasting effect of the complex ligamented charge holders is the best. Through comparing the effective plastic strain in the slits direction and vertical slits direction of the complex ligamented charge holders, we obtained that the effective plastic strain is the slits direction is 2.93 times of that in the vertical slits direction. After companing the pressure of surrounding rock in the far zone, we observed that the blasting pressure in the far zone of the complex ligamented charge holders is the lowest, which may lead to the minimum degree of injury to the surrounding rock and full use of the energy.