Symmetrical impact experiments for single crystal LiF were conduced at two-stage light-gas gun with a VISAR diagnostic. Longitudinal and bulk sound velocities, and unloading path of LiF were obtained up to 79.1 GPa shock pressure. Experimental results indicate a good linearity between the Lagrangian longitudinal sound velocity and the particle velocity. There is no evidence of shock-induced melting or phase transition for LiF in the present pressure range. The LiF unloading path and velocity profiles show a clear transformation from the elastic release to the plastic unloading.

The fractural surfaces of the compression tested specimens have been observed by scanning electron microscope (SEM). Microstructure fractural characteristics of three energetic materials under compressive loading at different strain rates are obtained. Based on the material composition, the fractural mechanisms of the PBX and Comp. B under the loading are discussed, respectively, which attempts to explain differences of the fractural characteristics between the two explosives.

Shock behavior of silicon nitride ceramic was investigated by using a one-stage light gas gun facility. A new technique is developed to measure the spall characteristics of materials with embedded electro-magnetic particle velocity gauges in the sample. This method measures the particle velocity profiles inner the sample and particularly, the gauge located behind the spalling plane will disclose clearly the message of spallation of the sample, which differs from the usual methods such as VISAR and manganin gauge. By this method, we obtained experimentally the spall strength of silicon nitride ceramic of density 3.12 g/cm³ as 0.73 GPa, which fit the data of Nahme et al. The scab thickness was almost equal to the flyer thickness in the experiments, since the symmetry impact was used. The experimental results indicate that the particle velocity gauge method can be used to study the spllation behavior of non-electromagnetism materials. Since we used three gauges in one shot to record velocity profiles at different locations, so the Hugoniot data up to 3.6 GPa (as in elastic range) was also obtained.

At room temperature and up to 13 GPa, in situ energy dispersive X-ray diffraction measurements for a natural cassiterite, collected from Gejiu tin deposits, Yunnan, were performed by using diamond anvil cell instrument with synchrotron radiation at BSRF. The results show that cassiterite is stable up to 13 GPa and its parameters of unit-cell decrease with increasing pressure. On the other hand, the parameters of unit-cell we calculated are bigger than these of former experiments with synthetical cassiterite. According to Birch equation of state, K_T(0)=228 GPa. For natural cassiterite crystal, it is believed that Zr replacing to Sn may be the reason for expansion of unit-cell.

The detonation cellular structures caused by C₅~C₆ cloud fuel mixtures are studied under the initial atmospheric pressure and room temperature by improved soot foil technique. Sharp cellular patterns are obtained. Meanwhile, the effect of equivalence ratio and initiation energy on the detonation cell size are also discussed respectively. The experimental results show that the detonation cell size of C₅~C₆ increases almost linearly with the increase of the equivalence ratio, but the detonation cell size increases first then decreases with the increase of the initiation energy. Moreover, when the initiation energy gets high enough, the fine structures in cellular structures are observed.

Rice seeds (Oryza sativa L. cv. Yuexiangzhan) were soaked for 10 h or not soaked, then exposed to 75 MPa high hydrostatic pressure (HHP) for 12 h. The seeds treated by HHP and their control were sowed in the field. Activities of antioxidative enzymes (SOD, AsA-POD) in the leaves, Rubisco content, F_v/F_m and Φ_PSⅡ were measured to evaluate the effect of HHP on the growth and development of rice. Results indicated that HHP inhibited the increasing of pigment and protein content in the early growth stage (12 d). Activities of antioxidative enzymes were lower than that of the control at the moment. With days after sowing increasing, the content of pigment and protein in the treatment were higher than that of the control (Yuexiangzhan). Antioxidative ability of rice treated by HHP was stronger than that of the control at the 32th days after sowing. The content of Rubisco, including Rubisco large subunit and Rubisco small subunit, was higher in the treated rice than that of the control at the natural low temperature.F_v/F_m and Φ_PSⅡ of treatment and control decreased at noon but can recover at evening, and recovery of treatment was better than that of the control. These results suggested that difference in growth between the treatment and control was due to the effect of HHP on the activities of antioxidative enzymes of rice possibly. Furthermore, HHP may enhance rice's resistance to low temperature.

Using the wheat seed of Yumai No. 18 as material, the effect of high pressure on seed germination and seedling growth of wheat was preliminary studied, and seedling growth of wheat that treated under 95 MPa pressure in various time was investigated. Results showed that, in 50~95 MPa pressure, all vacuum-packed seeds could not germinate; the germination of seeds that packed in water was inhibited significantly; the germination power and germination rate of seeds soaked for 6 h and packed in water were slightly inhibited. These indicated that water could alleviate the harm of high pressure to wheat seed. The average seedling height and seedling fresh weight of wheat seeds treated by 95 MPa pressure in various time both exceed CK.

Campbell's experimental studies of behaviors of initiation and after-initiation for homogeneous explosives were introduced and analyzed, but initiation conditions were not dealt with. Campbell's experimental results showed that detonation originated at the gap-explosive interface some microseconds of induction time later after the shock entered the nitromethane (NM). In other words, detonation is initiated by shock not instantaneously but directly (namely, not to pass through other processes, such as deflagration). The experimental data were newly treated, then they showed obviously that after initiation of detonation in NM the net detonation velocity is less than the normal detonation velocity. The experimental values of induction time decrease from 3.06 μs to 0.705 μs if the efficient pressures of shock wave increase from 8.82 GPa to 12.14 GPa. The two-phase repulsive-translation (A, m) equation of state was used to describe states of detonation product, and formularies of estimating induction time were derived newly and strictly from the thermal initiation theory. The calculated values of induction time estimated by the new formularies decrease from 248 μs to 0.99 μs if the efficient pressures of shock wave change in the same region. The calculated values of induction time are markedly higher than the experimental values. Thus this indicates that the thermal initiation theory is not applicable to describe the behaviors of shock initiation of NM. The cause is that the explanation of behaviors of shock initiation for homogeneous explosives with the thermal initiation theory does not accord with microscopic motion image of substance. Therefore, the thermal initiation theory is not the applicable one to describe behaviors of shock initiation for homogeneous explosives.

Brittle materials can be pulverized near the tip of the penetrator under high-velocity impact. This paper considers the pulverization of brittle materials and divides the target into the pulverized, cracked and elastic regions, and derived the cavity expansion pressure, viz. target resistance R_t of A-T model (modified hydrodynamic model) based on static cylindrical cavity expansion theory. The influences of the pressure-shear coefficient on R_t and stress fields are discussed. The depth of penetration is calculated using A-T model for a tungsten long rod impacting brittle target at 1.5~4.5 km/s. The calculated results of this model are compared with the experimental data and the results of other models.

The Linear relationship between shock wave velocity D and particle velocity u is very important to obtain high pressure equation of state and dynamic properties of materials under shock loading. In this paper, the least absolute value method is adopted to fit the D-u line of several kinds of materials, and comparing with the generally accepted least square method. Results show that for the experimental data which scatter small (e.g., non-porous samples), the two methods obtain almost the same results; but for the experimental data which scatter large (e.g., porous samples), the two methods obtain different results. Anyway, the least absolute value method has small average absolute error than the least square method. The reason of the different result between the two methods was addressed.