The free surface velocity profile of AD95 ceramic target was measured through laser interferometry under one-dimensional plane strain shock compression.Whether failure wave happened and its relationship with material property were discussed by the analysis of velocity profile characteristic.In an impact stress range from 4.4 to 7.3 GPa (σ_HEL is about 5.5 GPa), the free surface velocity profile has no appearance of reload signal, which means that there is no appearance of seriously damaged and fragmentized interface as that observed in glass and rock, like a failure wave.The analysis about the free surface velocity profile indicates that the calculated characterizing time difference is regularly less than the experimental value, and the rising foreland has a dispersive property even though the loading stress is less than σ_HEL.These findings demonstrate that, to some extent, AD95 ceramics might have produced a certain weak compressive damage at the low-stress region.The fracture toughness is a significant ingredient that affects the failure wave phenomena.Materials with relatively lower fracture toughness are prone to form microcracks extension, connection and finally lead to the serious breakage and shatter into pieces, which means the appearance of failure wave.

Axial compression on stainless steel spherical shells was performed under different loading styles by quasi-static tests, and the deformation energy of spherical shell was calculated.The stress distribution was observed through the photo elastic experiment so as to analyze the deformation model of hemispherical shell under static load.It can be seen that, the maximum stress occur near the loading point at the beginning, and extends outward in a circular form with the compression depth increases, eventually larger stresses distribute near polygon vertex, loading point and the region between them.It's also simulated by ABAQUS software to analysis the influence of loading method and hemispherical shell size on deformation mode.The result shows:The ability to resist deformation of spherical shell decreases along with the R/t increase; under flat nosed compression, the contact force of spherical shell decreases after reaching the peak, but it doesn't under other loadings; the increasing ratio of contact force is only related with thickness, but not with radius.

Changing the distribution of the thermal couple, a new experimental assembly, which is stable at extremely high temperatures, has been developed for the cubic press.Test experiments showed that at 5 GPa, this new experimental assembly can be stable at 1 600, 1 800 and 2 000 ℃ for more than 48 hours, about 30 h and about 10 h, respectively.Additionally, the temperature gradient in the new experimental assembly is very low:at 1 454 ℃, it is about 27 ℃/mm in the 4 mm long central part of the graphite heater.Long stable duration at extremely high temperatures and low temperature gradient make this new experimetal assembly suitable for the high-pressure experimentation in Geosciences.

We measured the electrical impedance spectra of two amphibole eclogite samples collected from Shangnan county of Shanxi province at 1.0 GPa within the frequency range of 10^-1-10⁶ Hz.The results indicate that the complex impedance depends on the frequency and temperature.At a given temperature, the modulus of complex impedance decreases with the increasing frequency, and the phase angle first decreases and then increases with the increasing frequency.At a given frequency, the modulus decreases with the increasing temperature and the phase angle increases with the increasing temperature.The range of electrical conductivity value of amphibole eclogite is 10^-6-1 S/m, and the relationship between conductivity and temperature can be fitted by Arrhenius relation.The activation enthalpies derived are 33-58 kJ/mol at low temperature and 108-163 kJ/mol at high temperature, respectively.The conduction mechanism of amphibole eclogite is likely related to the electron hopping between Fe²⁺ and Fe³⁺.

Using first-principles which base on density functional theory, systematacially research on the electronic structure and lattice dynamics of ternary intermetallic compounds CaAlSi under high pressure was conducted.The ternary intermetallic compounds CaAlSi has six angles honeycomb structure similar with MgB₂, except that Ca atom replaces the position of Mg atom, Al atom and Si atom occupy the position of B atom disorderly.According to calculations on energy band and three-dimensional Fermi surface, we discover that energy band experiences electron topological changes nearby CaAlSi fermi surface under pressure.The pressure can lead to electronic topology structure phase change.The lattice dynamics of the CaAlSi are studied under pressure.The investigation shows that optical branchs soften along the A-L-H line and phonon modes harden under pressure.It indicates that the structure of the intermetallic compound is unstable under pressure, and a new structure may be found in the case of increasing pressue.

Using a plane-wave pseudo-potential density functional theory method, the equilibrium and elastic properties of fcc and bcc ZrN structures under different pressures were studied.The relationship between enthalpy and pressure of fcc and bcc structures was also investigated, and their relative stability was discussed.From the analysis of the relationship between the total energy, enthalpy with pressure, elastic properties and the phonon spectra, conclusion is found that transformation from the fcc structural phase to bcc structural phase occurs at 205-235 GPa.

Within the framework of hydrodynamic-elastoplastic model, equations were established to characterize the response behaviors of aluminum foam under explosive impact.In order to solve the equations, the equations were transformed into discrete Lagrange difference forms in uniform grid.The numerical calculation method was programmed and applied to one-dimensional numerical calculation of underwater explosion and shock response of Al foam in the water.A good agreement is achieved between the numerical calculation, experiment data and results simulated by LS-DYNA-3D, which varified the feasibility of the proposed methodologies to be applied to describe the behaviors of Al foam under explosive impact.The thickness of foam material shell has great impact on the pressure field of underwater explosion.

Dust explosion experiments were carried out in a 5 L closed cylindrical vessel using cornstarch dispersed with compressed air and ignited by high-voltage spark, for further study of the factors which affect the dust explosion parameters.With different dispersion pressure, the influence of ignition delay time on the pressure parameters of dust explosion was studied, and the experimental results were analyzed theoretically.The results show that the influence of ignition delay time on explosion pressure and rise rate of pressure is significant, a critical value of dispersion pressure is found.When dispersion pressure is higher than the critical pressure, there is an optimum ignition delay time, making the explosion pressure and pressure rise rate maximal.With the increasing of dispersion pressure, the optimum ignition delay time decreases.When dispersion pressure is lower than the critical pressure, the pressure of dust explosion rises as the ignition delay time increases.

"Ablation mode" laser propulsion works on the counterforce generated during the interaction between high-power laser and propellant carried by thruster.The structural geometry of the nozzle of "ablation mode" laser propulsion thruster has important influence on the propulsion performance.The effect of nozzle length L on propulsion performance was carried out by experiment and numerical simulation.Experimental results indicate that both the momentum coupling coefficient and the specific impulse increase as L increases, but the increasing tendency of momentum coupling coefficient slows down with the increase of L.Considering the effects of both propulsion parameters and weight of thruster, the formula of optimal length of nozzle is derived with the largest velocity increment of the thruster.The thrust-time curves and impulse-time curves are obtained by numerical study using software FLUENT.The simulation results agree with the experimental results.

In allusion to the question of damage assessment for KE-Rod penetration on target, a single-impact damage index model was proposed based on numerical results of KE-Rod penetration on target with different rod-angles(varying from -60° to 90° by step of 30°) and velocity-angles (varying from 0° to 75° by step of 15°) using finite element method.Results show that the damage index increases with velocity-angle in general, but when the velocity-angel is 60° or 30°, the damage index reaches maximum while the rod-angel is the same.The result of simulation for vertical penetration is in good agreement with the experimental data, and the error is 4.06%, which validates the feasibility of the scheme.

20 L spherical explosion tank is one of the standard devices used to test the dust explosion characteristics parameters.The motion law of dust particle in closed space is useful for the study of the best ignition delay time in dust explosion.The dust flow process in 20 L spherical tank was investigated by numerical simulation based on computational fluid mechanics theory.The dispersion condition of aluminite particle of different sizes was monitored, and the particle subsidence times of different sizes were compared.It is shown that the particle subsidence time decreases as the particle size increases.When the particle size is bigger than a certain degree, the dust will not disperse in the closed space.

There is not a widely recognized theory which can explain the heat transfer of subcooled pool boiling under high pressure, so the mechanism of heat transfer of subcooled pool boiling is not clear.In order to disclosure the physical mechanisms of heat transfer for the subcooled nucleate pool boiling and obtain the relation between the bubble departure frequency and active cavity radius, the functions of heat transfer were analyzed according to the distribution of active cavity on boiling surfaces.A mathematical model was derived based on statistical treatment for the subcooled nucleate pool boiling heat transfer under high pressure.The proposed model for the heat flux of the subcooled nucleate pool boiling heat transfer is found to be a function of wall superheat, liquid subcooling, active cavity size, the contact angle and physical properties of fluid.No additional or new empirical constant is introduced.Comparing the model predictions with the existing experimental data, an excellent agreement between the model predictions and experimental data is found for different liquid subcoolings.The validity of the mathematical model for the subcooled nucleate pool boiling is thus verified.The analytical model reveals the physical principles of the heat transfer of subcooled pool boiling.

The existing reactive flow Lagrange analysis methods are still inadequate to solve the particle velocity history from a series of gauges embedded in material.Based on this point, a new Lagrange analysis method combined the inverse analysis with self-consistent examination was presented.The theoretical accuracy of this method can achieve that the M-order partial derivative of the stress equals zero, and the self-consistent examination is satisfied.Besides, this method is applied to process the experimental data of the light gas gun.Comparing results of this method, experimental data and the traditional inverse analysis results, it turns out that this method not only makes the particle-line function reflecting the behavior of various physical quantities along the particle-line, but also reduces the accidental error of the particle-line.

As the unknown nature of mechanism of projectile penetrating the concrete target and the complexity of the mechanical properties of concrete, the projectile penetration concrete can be seen as a gray process.The establishment of methods and processes about the gray simulation and prediction model GM (1, n) were described.Through the gray model GM (1, n), the simulation and prediction of penetration depth of projectile penetrating the concrete target can be achieved.The calculation results show that the model simulation and prediction of projectile penetration depth of concrete penetration is feasible, the result is valid, with a smaller amount of calculation.

A one-dimensional model of lattice physical mechanics was built up to study the atomic thermal vibration in a constant volume state.According to the lattice dynamics model, An equation of state of solids which is similar to the Mie-Grüneisen's, was deduced absolutely from vibration mechanics.The mechanical implication of thermal pressure was ascertained, that thermal pressure was the average value of thermal vibration force in time domain.The relationship between Grüneisen parameter and thermal vibration frequency shows that the Grüneisen parameter of a real solid corelates with its crystal structure.The differential expression between Grüneisen parameter derivated from a simple cubic crystal and cold pressure was obtained, which agrees with the D-M relation.

The effect of raw material characteristics (Peach varieties) on the texture of canned yellow peach processed by high hydrostatic pressure (HHP) and thermal treatment was investigated.The results show that different varieties have no significant influence on the hardness of canned yellow peach processed by HHP, while the hardness of canned yellow peach processed by thermal treatment decrease significantly and the syrup viscosity has a marked increase.Canned yellow peaches of "Senkelin" varieties get the highest hardness and the best texture after processed by HHP and thermal treatment.The microscopic structure analysis indicate that different varieties of yellow peach processed by HHP have no significant effect on the cell morphology and the cells keep the original shapes.With heat treatment, the cell shape changes greatly; the cell deformes and shows no regular shape; the cell gap is significantly increased.The canned yellow peach can be kept in good texture by HHP, which makes HHP has a more extensive adaptability compared with heat treatment.

We investigated the use of high hydrostatic pressure (HHP) processing for shucking abalone (Haliotis discus hannai Ino) and the changes in physical properties of HHP-shucked abalone.The results show that HHP is a very effective method for abalone shucking.Under the treatments of 200 MPa/1 min and 300 MPa/0 min, the yields of HHP-shucked samples increase by 18% and 16% respectively, and the shucking time saves 69% and 72% respectively compared with the manual shucking samples.Moreover, the counts of total aerobic bacteria (TAB) of HHP-shucked abalone reduce significantly to 270-350 cfu/g from 2.2×10³ cfu/g.Compared to the control, the moisture of HHP shucking samples significantly increases, however the changes in pH are not obvious.The samples treated by HHP shucking become more light, green and yellow.With the increasing of treatment pressure and time, the hardness of HHP shucking samples shows increase trend, while the springiness decreases.Based on the research results, it indicates that the optimum shucking condition that causes minimal changes in adductor muscle of abalone appearance is 300 MPa/0 min.

High hydrostatic pressure(HHP) of 300, 450, 600 MPa was applied on waxy corn starch as a physical modification.The effects of high hydrostatic pressure on gelatinization and retrogradation properties of waxy corn starch were investigated.The appearance and particle size of the granules were studied by micro-polariscopy, scanning electron microscopy and laser diffraction instrument.Combining X-diffraction and DSC spectrum, the change from crystal to non-crystal was confirmed.A compressing effect on HHP treated starch at 300 MPa was proved by the decreased granule diameter, the strengthened H-OH stretching in the infrared spectra and a slightly increased in onset temperature, peak temperature, and enthalpy of gelatinization; For HHP treated starch at 450 MPa, the starch gelatinization was observed by light microscopy, FTIR spectra and confirmed by DSC analysis.The birefringence of granules disappeared, the bands weakened in the infrared spectra, and onset temperature, peak temperature, and enthalpy of gelatinization decreased sharply.In contrast, the retrogradation of HHP treated starch at 600 MPa was observed, which was illustrated by the reappearance of birefringence in granules and the biphasic gelatinization endotherms.The results prove that the granules under high hydrostatic pressure processing experience "3 development stages" including compressing, disappearance of crystalline structure and recrystallization after granule disintegration.