Zhang Ming-Jian

Effective Shear Viscosity of Iron under Shock-Loading Condition

We combine the flyer-impact experiment and improve the finite difference method to solve whether the shear viscosity coefficient of shock iron is more reliable. We find that the numerical simulated profile agrees well with the measured one, from which the determined effective shear viscosity coefficients of shocked iron are 3000 ? 100 Pa?s and 4000 ? 100 Pa?s, respectively, at 103 GPa and 159 GPa. These values are more than 2000 ? 300 Pa?s of Li Y L et al.[Chin. Phys. Lett. 26 (2009) 038301] Our values are more reasonable because they are obtained from a comprehensive simulation for the full-shocked perturbation evolving process.

A High-Spectral-Resolution Laser Raman System and Its Application in Shock?Compressed Benzene

Raman measurements play an important role in examining the molecular changes associated with shock-induced structural and chemical changes in condensed materials. We combine a high spectra-resolution Raman system with a two-stage light gas gun to provide better quality data than the transient Raman system used previously. Representative measurements are presented for the shock compression of benzene. The high spectral resolution data have provided an insight into molecular changes that could not be obtained from time-resolved methods.

Multi-Shock Compression of Dense Hydrogen?Helium Mixture Beyond 100 GPa

A cryogenic target system for preparing the dense gaseous samples is established on a two-stage light-gas gun and is applied to study the equation of state of hydrogen?helium mixture at higher pressures and at high temperatures by means of the multi-shock technique. The recorded optical radiation signal clearly indicates the beginning moments of the third-, fourth-, sixth-, eighth-, and tenth-shock processes, which are in good agreement with the predictions of the Mansoori?Canfield?Ross variational perturbation theory up to the observed ultimate state of 104?GPa.

Electrical Resistivity of Silane Multiply Shock-Compressed to 106 GPa

The liquid silane sample, prepared by liquifying pure silane gas at 88.5 K, is multiply shock-compressed to 106 GPa by means of a two-stage light-gas gun and a coolant target system. Electrical resistivity is measured for fluid silane during the period of multi-shock compression in the pressure range from 63.5 GPa to 106 GPa. It is shown that the electrical resistivity reduces to the order of 10−3–10−4 ohmm after the second shock arrived, which is two orders higher than those of typical melt metals. Though the metallization transition could not be confirmed under the loading condition of our shock experiments, its resistivity drops sharply along with the pressure rise. The phenomenon might be caused by silane decomposed during the pressure loading, due to the fact that, above 100 GPa, we find that its resistivity is close to hydrogen under the same pressure.

Crystallization of water induced by fused quartz under shock compression

In this paper, we study the crystallization of water due to fused quartz effect under shock compression by a gas gun and light transmission tests. The experimental results indicate that at 1.28 GPa water rapid crystallizes when the water has come into direct contact with the quartz glass. On the contrary, freezing cannot occur within 2 μs, demonstrating that the observed phenomenon of the liquid-solid phase transition of water can be promoted by the fused quartz. The dynamics of the phase transition is also discussed in this paper.