Room temperature ionic liquid, which is viewed as a kind of super green solvent, has broad application prospect in industrial production.In this paper, the intrinsic relationship between the condensed structures and properties of room temperature ionic liquids under high pressure has been reviewed in detail.Furthermore, the mechanism of crystallization of room temperature ionic liquids is elucidated.Those fundamental researches will contribute to the application of room temperature ionic liquids.Based on the recent progress in the studies of room temperature ionic liquids, the relationship between the condensed structures and properties, potential application and development prospect under high pressure are highlighted, which may facilitate the research and application of room temperature ionic liquid in the future.

Heat conduction property of minerals and rocks at high temperature and high pressure is important information to understand the dynamic mechanism, temperature distribution and the thermal evolution history of the Earth.Measurements of the thermal diffusivity of minerals and rocks at high temperature and high pressure have important significance in earth science.However, the domestic research in this field has not started.A device for measurement of thermal diffusivity at high temperature and high pressure has been developed using an YJ-3000t multi-anvil press.The thermal diffusivity of basalt is determined at 0.5 GPa, 2.0 GPa and 20-500 ℃.The extrapolations of experimental results on basalt to atmospheric pressure are in good agreement with results from LFA427 laser-flash apparatus.It shows that the present setup can be used to measure the thermal diffusivity of rocks at high temperature and high pressure.

The first principle method based on the density functional theory is applied to study the equation of state of Au.The ground state calculation shows that the LDA (local-density approximation) potential is a more accurate exchange-correlation potential.The equation of state of Au over the density and temperature range of 9.3-42.0 g/cm³ and 1 000-50 000 K is obtained by the first principle molecular dynamics method, and the Hugoniot curve is also calculated and compared with the results of experiments and other theories.The theoretical calculations agree well with the experimental ones.

The results of split Hopkinson pressure bar (SHPB) and quasi-static compression tests for aluminum foam at different strain rates and temperatures are used to explore its constitutive relation.It is revealed that there is a coupling of the temperature effect and the strain rate effect, namely the higher the temperature is, the more significant the strain rate effect of the aluminum foam is.In the framework of Sherwood and Frost constitutive relation, with appropriate correction of the strain rate sensitivity coefficient considering the coupling effects between temperature and strain rate, a constitutive equation of aluminum foam is proposed.The results show that the revised constitutive equation can fit the experimental results well in the density, temperature and strain rate ranges considered.

Theory predicts that B-C-N compounds may exist in many structural forms and have excellent physical properties.Synthesis of such materials is attracting the attentions of scientists.A two-stage light-gas gun and the corresponding shock-recovery technology were applied to explore the synthesis conditions of B-C-N compound of new phase structures under 40 GPa pressure.XRD (X-ray diffraction), HRTEM (high-resolution transmission electron microscopy), ED (electron diffraction) and XPS (X-ray photoelectron spectroscopy) analysis show that all three precursors with different atomic ratio of B, C and N can generate a new dense phase of B-C-N compound under strong shock loading of 40 GPa.Single crystals of 60 nm are directly observed in the recovery sample.The new B-C-N compound of such structure has not been reported in the literature before.Therefore, this discovery is of significance for exploring new structures of B-C-N compounds and the synthesis conditions in future; meanwhile, a new structure of B-C-N compound is waiting to be studied by theoretical researchers.

Using a self-designed measuring device, the argon density has been measured at 300 K for pressure lower than 60 MPa.The second and third virial coefficients are obtained by fitting the experimental data, and the new parameters of Lennard-Jones potential are derived from the experimental virial coefficients.Furthermore, the temperature-dependent virial coefficients are calculated by these new potential parameters.The calculated densities from these virial equations are compared with other experiments and empirical equation of states for determining the application range of the present equation.

The physical processes, including input and output pressures of explosive, reaction zone propagation caused by low amplitude shock, are tested by PVDF gauge and high-speed photography.The shock propagation image and the course of input pressure in explosive with different attenuator thickness are gained.According to the results, the law of pressure variation and characteristics of reaction zone propagation in explosive under low amplitude shock are analyzed.Furthermore, some safety questions are discussed such as the relation of shock increase and power ability and the effect of confinement on reaction increase and leak.

To evaluate the hazard of combined gaseous epoxypropane-aluminum dust explosions, a 5 L spherical exploding device was used to measure the lower limit of explosion densities of aluminum dust in aluminum dust-air mixtures and gaseous epoxypropane-aluminum dust-air hybrid mixtures, and gaseous epoxypropane in gaseous epoxypropane-air mixtures.The results show that the existence of gas epoxypropane can reduce the lower limit of explosion density of the hybrid mixtures, and enlarge the rate of pressure rise of the hybrid mixtures; at low aluminum dust concentration, the maximum overpressures rise due to the existence of gaseous epoxypropane, and then fall with increasing aluminum dust concentration.

Flame front with high temperature is one of the most main hazardous factors during indoor deflagration accidents of natural gas.Spread range of flame front reflects the hazardous region and the severity of this kind of accidents in a great degree.Combined with one indoor natural gas deflagration accident, the indoor natural gas deflagration processes under different gas concentrations, especially the spread range of flame, were studied deeply by virtue of computational fluid dynamics technology.The results show that gas concentration takes great influence on spread range of flame.The higher the gas concentration, the greater the spread range of flame.The reason of the above conclusions is that the movement and diffusion of unburned fuel induced by precursor shockwave and turbulence promote further spread of flame and enlargement of flame region.

A high-velocity earth-penetrating structural projectile is designed, and experiments of projectiles with mass of 0.15 and 1.5 kg and impact velocity ranging from 1 030 to 1 630 m/s are carried out.The projectile structural response, mass loss and critical survival velocity for projectile in high-velocity condition are discussed.The results show that the three failure mode of projectile in high velocity penetration condition are head eroding plus parietal ablation, bending/tail crushing, and structure crushing, and the head eroding and mass loss increase with impact velocity.

For special requirements of penetrating multi-layer steel target, a design of explosively formed projectile (EFP) and its experimental study have been carried out.A compressed EFP assembly with a 60 mm diameter of liner has been designed using the curved variable thickness liner design.The shape and velocity of the EFP when penetrating through the multi-layer steel target were measured with X-ray photography.According to the experimental results, the EFP shows the characteristics of moderate speed, good compactness and small length-radius ratio.In the process of penetrating multi-layer steel target, the EFP has stable performance, and smash phenomenon does not exist.The experimental results show that it can penetrate through the six-layer steel target with thickness of 6 mm and spacing of 2 m.

Aimed at the requirement of large hole diameter and deep penetration depth of tandem warhead precursor charge, by using LS-DYNA finite element software and orthogonal optimal design method, the influence law of the liner and foam structural parameters of K-charge on the formation of the shaped jet was studied.The relatively high tip velocity was gained, when the liner curvature radius was selected within a range between 90 and 110 mm, and the eccentricity was taken between 35 and 40 mm.The influence sequence of the structural parameters, including eccentricity, curvature radius, thickness, foam diameter, opening angle, and cone angle, on the jet formation indexes (tip velocity, tip and tail velocity difference) was obtained, and the optimal combination of K-charge structural parameters was acquired.The X-ray imaging and steel penetration experiments were also carried out.The experimental results show that the penetration depth and hole diameter reach 3.73 and 0.36 times of charge diameter, respectively, and the penetration hole is relatively homogenous.The simulation results are in good agreement with the experimental results, which provides a reference for the further study of tandem shaped charge technique.

In order to solve the problem about fast perforation of hunk fraise with enough depth and width, a new tandem shaped charge structure is proposed, which is composed of two same structure of EFP (explosively formed projectile) shaped charge.Using finite element software LS-DYNA3D, the forming process of this new structure and the effect of delay time on the forming process of tandem EFP are simulated and analyzed.On this basis, an experiment for tandem EFP penetrating 45 steel target is conducted.The results show that the tandem EFP charge can make full use of the penetration capabilities of two shaped charge, and the penetration effect is greatly improved.

While testing the strength of a rescue cabin under blasting, the door and other special structures of the underground coal mine rescue cabin are usually simplified to shorten the time of calculation.When the rescue cabin is attacked by blasting, the large deformation or failure frequently occurred in those structures.In order to simulate the dynamic response of these special structures without increasing the calculation time, a numerical method based on LS-DYNA named Link-Interface is studied.The cabin door and reinforced ribs are calculated in detail by this method.The results show that as the peak pressure of blast loading is 1.5 MPa, the largest deformation appears at the middle of cabin door, and its maximum displacement diminishes exponentially with pressure rise time.Circumferential ribs play more important role in reducing the surface displacement and increasing the strength of the cabin than axial ribs.The results can provide a certain theoretical basis for designing and testing an underground coal mine rescue cabin.

In order to reflect the temperature rise process on the sliding electrical contact interface exactly, a numerical model of imperfect electrical contact (ImPEC) during hypervelocity sliding in electromagnetic railgun is developed.The model is implemented with finite difference method, and the thermal effect of contact resistance is simulated.The results show that more heat is generated on the contact interface due to the ImPEC.With the increasing of the thickness of the contact layer, the temperature rise on the contact interface becomes higher.Due to the velocity skin effect, the heat generated by the contact resistance is mainly concentrated at the trailing region of the interface.Furthermore, the calculated temperature is significantly influenced by the thermal conductivity and the shape of the input current.The results provide a theoretical basis for estimating the material state of sliding interface and predicting the contact transition.

In order to study the dispersion of solid particle under the loading of shock tube, a numerical simulation of the dispersion of quartz sand with a mass of 5 g and different diameters of 2.00-3.00 mm, 0.80-1.10 mm and 0.42 mm respectively was carried out by means of DPM (dispersion phase model) of FLUENT.For the particles in the center of the quartz sand cloud during the dispersion, the average velocity and the average displacement along the loading direction were obtained.The numerical simulation results have a good agreement with the experimental results.Compared with the experimental results, the simulation result is slightly larger, probably because the dissipation energy on the sieve is ignored in the numerical simulation and the paper film of shock tube is considered to be ruptured instantaneously in the assumption.

An experimental testing technique with light screens is developed to measure the velocity and distribution of warhead fragments, especially small fragments.The basic theory and main principle of the light screens were discussed, and dynamic experiments were designed and carried out to test the velocity and distribution of warhead fragments by the light screens.Experimental results show that the light screens can accurately measure the velocity and distribution of the warhead fragments with a dimension of 5 mm.

According to the dynamic characteristics of a new capacitive high bore pressure tester, which is decided by the vibration characteristics of the pressure tester shell subjected to pressure, the dynamic model of the tester shell under external pressure was established, and the dynamic properties of the tester shell were studied.The calculation results show that the first vibration frequency of shell radial vibration is above 75 kHz, and the frequency spectrum of the bore pressure is below 5 kHz.Consequently, the influence of shell vibration on the test precision of bore pressure can be ignored.

The objective of this work was to study the effects of fermentation with lactic acid bacteria and dynamic high pressure microfluidization (DHPM) on physicochemical properties of dietary fiber in soybean residue.The results showed that fermentation and DHPM produced an increase of soluble dietary fiber (SDF) and a decrease of insoluble dietary fiber (IDF), and raised the SDF/IDF ratio to 1/2.6.They both modified hydration properties and oil holding capacity greatly, but did not affect cation exchange capacity significantly.The sample showed a lower bile acid binding capacity after fermentation, but a higher capacity after DHPM treatment.Therefore, fermentation with lactic acid bacteria and DHPM could be considered as good methods to improve the functionality of dietary fiber in soybean residue.

The qualities changes of carrot juice treated by high hydrostatic pressure (HHP, 600 MPa, 5 min) and thermal process (95 ℃, 5 min), as well as in storage at 4 and 27 ℃, were studied.The results show that L, a, b and ΔE increase significantly (P < 0.05) after thermal process, botha value and ΔE of HHP treated sample increase significantly (P < 0.05), while forL and b value, there are no significant change (P > 0.05).In the storage period, L, a, and b increase while ΔE decreases.There are no significant changes in pH value, total soluble solid content and turbidity after HHP or thermal treatment.The total soluble solid content increases, the turbidity decreases, while pH value does not change significantly in the storage period.Carrot juice is closer to Newtonian fluid after HHP treatment, and the flow behavior indexn of thermal treated carrot juice increases first and then decreases during storage.The concentrations of α- and β-carotene do not change after treatment while decrease significantly (P < 0.05) in the storage.The antioxidant activity of carrot juice increases significantly (P < 0.05) after treatment.The PSD (particle size distribution) parameter does not change significantly (P > 0.05) after treatment, while new particle appears in carrot juice during storage.