Lamellar single crystals of poly (L-lactic acid) (PLLA) were prepared from its dilute xylene solutions under 500 MPa by an isothermal crystallization method.Their morphology and structural features were characterized by transmission electron microscopy, raman and infrared spectra.The results show that the single crystals of PLLA grown under high pressure are only α-type crystal structure, and their average size is larger than those obtained under atmospheric conditions.Under high pressure, crystal nucleus on different sides have different growth rates, leading to the formation of asymmetric rhombic lozenge.It is found that high pressure has induced conformational distribution change of the PLLA single crystal.Furthermore, during the PLLA crystal growth period, high pressure induction is favorable for promoting the nucleus number and depressing the grown of PLLA crystal.

The line-image VISAR was applied in a detonation experiment, in which a flyer with Zigzag trenches was driven by a divergent detonation wave.The free surface velocity of a 12 mm-long line on the flyer was obtained, and the velocity distribution on the free surface was also recorded at 1, 3, 5 μs after the free surface started moving.Finally, the experimental model was simulated using LS-DYNA program, the results are in good agree with the experimental results, which prove the potential of Line-Image VISAR in heterogeneous experiment.

Experimental and numerical simulation researches were presented on dynamical behaviors of cylindrical shell structure affected by lateral explosion loading.Impact experiments of explosion loading caused by cylindrical TNT charge on the Q235 steel cylindrical shells with different wall-thicknesses were carried out.The deformation modes of cylindrical shells were analyzed under explosion conditions with different charges and stuctures.These deformation modes include local dent mode(Mode Ⅰ), coupling of local dent and whole bending mode (Mode Ⅱ), whole strcture collapse mode (Mode Ⅲ) and coupling of local perforation and whole strcture collapse mode (Mode Ⅳ).By means of the finite element computer code LS-DYNA, the nonlinear dynamic response process of the cylindrical shells subjected to explosion loading were numerically simulated with Lagrangian-Eulerian coupling method.The deformation process of the cylindrical shells and the final modes were described.The numerical simulation results are in good agreement with experimental data.The results provide a reference for the classification of explosion damage and the design of explosion-resisting structures.

This paper describes the formulation of the complete equation of state (EOS) for several materials, based on two universal EOS, proposed by Vinet et al, as well as Parsafar & Mason.And we discussed the formulation of the EOS from the thermal mechanics state expressed by thermal-pressure coefficient and specific heat coefficient.Finally, we fitted the obtained EOS with those obtained shock wave data from references by linear fitting method.The calculated shock Hugoniot state from the obtained two complete EOS are compared with shock Hugoniot data, and good agreements are showed.

This paper introduces an IMEX (implicit-explicit) Additive Runge-Kutta method, which was applied to resolve the stiff source term into the stiff part and non-stiff part, and the stiff part was solved implicitly while the non-stiff part was handled explicitly.The numerical calculation of the gas-phase detonation show that the method can deal with the stiff problems caused by the source term, accurate capture the discontinuity and description of the structure of the Mach reflection, meanwhile the features of cellular pattern agree well with the experimental results.

The pressure-induced structure transformation and lattice parameters of lanthanide mononitrides were investigated using first-principles calculations based on density function theory.The effect of the 4f electrons spin polarization on the pressure-induced phase transition for lanthanide mononitrides was analyzed.The results show that 4f electrons spin polarization produces a tremendous influence on the pressure-induced structural transformation for GaN, TbN, DyN, HoN and ErN, while the effect is quite small for other lanthanide mononitrides.

In order to study the penetration ability of the ceramic composite target, a damage factor is proposed to characterize the radial damage of the material in the cracked zone in the cavity expansion theory (CET).Based on the CET of ceramic with damage factor and the CET of metal, the composite target composed of a ceramic tile and a semi-infinite metallic substrate is theoretically modeled.In this model, the effects of the finite lateral boundary are ignored by assuming that the lateral dimension is infinite.Depending on the property of the penetrator-target interface to the ceramic-metal interface, 4 distinct possibilities arise.The stress state and target resistance of each possibility are calculated respectively.The conclusion shows that:(1) the pressure-shear coefficient in the comminuted zone has an obvious effect on the penetration property of the ceramic, while the tensile strength and compressive strength have a little effect on it; (2) when the composite target is approximated as an infinite target, the relative size of different zones and the cavity expansion pressure are not affected.

Aluminum fiber explosive containing explosive and aluminum fiber which is made from pure aluminum is a novel non-ideal explosive.Pressure-time curves of aluminium fiber explosive at different positions were measured by underwater explosion experiments.The peak pressure, impulse, shock wave energy and bubble energy were obtained by analyzing the pressure-time curves.Pressure-time curves can be described by exponential and hyperbolic function at distinct stages.The fitting effect of bubble oscillation curve using normal distribution function is not ideal.That specific bubble energy is 52%-58% of the explosion energy, which shows the effect of adding fiber.The explosive energy declines to 75%-85% of the explosion heat because of the imperfect reaction and crushing energy cost of Al fiber.

Ballistic experiments and numerical simulation were adopted to analyze the anti-penetration performance of double hardness explosively welded steel/aluminum plates penetrated vertically by a spherical projectile.A 14.5 mm diameter smoothbore gun was used to launch the spherical steel projectile with a diameter of 6 mm, and the finite element code LS-DYNA3D with the coupling algorithm of finite element and smoothed particle hydrodynamics (FE-SPH) was applied to simulate the penetration process.The effects of thickness and strength of the explosively welded plates on the anti-penetration performance and damage mechanism were analyzed.The results show that the damage mechanism of the steel front layer is shearing and plugging and that of the aluminum rear layer is prolonging deformation.For a two-layer steel/aluminum plate, the anti-penetration performance is the worst when the thickness ratio of steel and aluminum plate is about 2/3.The numerical simulation results are well agreed with the experimental ones, so the FE-SPH method can predict the anti-penetration performance of two-layer explosively welded plates well.

By using plate impact and laser interferometer techniques, the refractive index of shocked LiF single crystal and its window correction at 1 550 nm wavelength were studied.The shock pressure in the LiF sample ranges from 38 to 124 GPa.The present results extend the refractive indexes of LiF single crystal at 1 550 nm, and give a linear LiF window correction relation at 1 550 nm below 124 GPa.The results provide an important reference for data analysis of window-mounted DPS (Doppler pin system) velocity measurement in shock experiment.

According to the logistic regression model based on statistical analysis, the experiments on the minimum ignition energy of different concentrations of nicotinic acid dust-air mixtures have been conducted in the Mike 3 tube by the calculation method of the minimum ignition energy of dust cloud which represented by probability, the volume of Mike 3 tube is 1.28 L.Utilizing SPSS software, the minimum ignition energy of various concentrations of nicotinic acid dust cloud when the ignition probabilities are 10% and 50% has been calculated.The results show that the minimum ignition energy of nicotinic acid dust cloud has a tendency to first decrease and then increase with increasing concentrations, finally maintain at a certain energy range.Compared with other standard calculations, the viewpoint of ignition as a statistical phenomenon appears to be more consistent with the test data in engineering, it can also meet the needs of different production environments for security control.

In order to obtain the size-control method of nanostructured ceria during the process of detonation synthesis, the nanostructured ceria powder was synthesized by detonation method with emulsion explosives, and the effects on the detonation velocity of emulsion explosive and the diameter of nanostructured ceria particles exerted by the droplets size of hydrate phase in emulsion matrix were studied.The emulsion matrix was characterized with scanning electron microscope (SEM) and its corresponding nanostructured ceria was characterized with transmission electron microscope (TEM), X-ray diffraction (XRD) and laser particle analyzer.The results indicate that the droplets size of hydrate phase in emulsion matrix affects the detonation velocity of emulsion explosives and the diameter of nanostructured ceria particles significantly.It is beneficial to achieve nanostructured ceria with small diameter and uniform size by decreasing the droplets size of hydrate phase in emulsion matrix.

Using split Hopkinson compression-shear bar, the friction coefficients between GO-924 explosive and three materials including aluminum alloy, rubber, and GO-924 explosive itself were investigated under different shock loading conditions.The results show that the rules of the 3 friction coefficient curves are different.For aluminum alloy, the friction coefficient varies between 0.166 and 0.176 and is independent of impact speed; for rubber, the friction coefficient increases steadily and is sensitive to impact speed; the friction coefficient between explosives increases at first and then decreases, which is likely to relate to explosive damage.

High-current pulsed electron beam (HCPEB) with different pulses was utilized to irradiate AISI 304L stainless steel.The surface microstructures of the irradiated samples were characterized in detail.In particular, the corrosion behaviors of the stainless steel surface with and without HCPEB treatment were evaluated.The experimental results show that the corrosion resistance of the stainless steel after HCPEB treatment is remarkably improved compared with the original sample.Beside the surface purification effect of eliminating impurities due to the crater eruption, the formation of dense surface passive layer, which effectively inhibits the pitting events, is also an important mechanism for the improvement of corrosion resistance of the irradiated materials.Transmission electron microscopy (TEM) observations suggest that a large amount of supersaturated vacancy defects combined with abundant line and planar defects are introduced when the material surface is subjected to the HCPEB irradiation.Furthermore, the agglomerations of the vacancy defects result in the formation of the vacancy cluster defects, such as vacancy dislocation loops and stacking fault tetrahedra (SFTs).Those structural defects in the irradiated surface layer promote the formation of a thick and dense surface passive layer.It prevents corrosive anionic species from passing through the surface oxidation layer and delays the corrosion process, resulting in the improvement of corrosion performance of the irradiated materials.

The heats of formation (HOFs) of a series of nitrocellulose (NC) were calculated by using density functional theory (DFT) and designed isodesmic reaction at B3LYP/6-311G^** and B3P86/6-311G^** levels.The results show that the difference between the values of HOFs of a series of NC calculated by these two methods is acceptable.The negative HOFs have relationship with the number of O—NO₂ bonds instead of their positions.Bond dissociation energies (BDEs) of O—NO₂ bond were also obtained at B3LYP/6-311G^** level.It is deduced that BDEs of O—NO₂ depend on the numbers of O—NO₂ bond rather than the nitrogen content of NC.The detonation velocities and pressures were predicted on the basis of Kamlet formula.It can be concluded that the detonation velocity and pressure will decrease with the increase of the number of O—NO₂ bonds.

In order to acquire the influence of warhead shell materials on fragments forming, 4 kinds of material, such as 82 steel, 50SiMnVB steel, 40CrMnSiB steel, 30CrMnSiNi2A steel, were studied to form fragments, using fragment warhead design software.The change laws of fragments scattering angle, initial velocity and mass distribution were obtained, and the fragment mass distribution was researched by experiment.It is found that, various alloy steels have similar almost the same influence on the fragments scattering angle and initial velocity, and have same diversification regular pattern along the warhead axial.Specially, the fragments scattering angle decreases at first and then increases, and its maximum initial velocity appears at the place about 72.5% of warhead length.But various alloy steel has very different influences on fragmens mass distribution.With materials ultimate tensile strength increasing and fracture toughness decreasing, the warhead damage extent improves and total fragments number increases by 39.3%.

In order to investigate the the influence of modified soluble soybean polysaccharides (MSSPS) on physicochemical properties of rice starch (RS), soluble soybean polysaccharides (SSPS) were modified by dynamic high pressure microfluidization at 80, 120 and 170 MPa, respectively.Different mass fractions (5.0%, 7.5%, 10.0%, 20.0% and 0) of these MSSPS and SSPS were added into RS.The experimental results are as follows:The swelling power, solubility and clarity of RS samples after adding MSSPS were increased compared to that of SSPS groups; the solubility and clarity of RS with addition of MSSPS were significantly affected by modified pressure, when the pressure reached 120 MPa, the solubility significantly increased (P < 0.05); the clarity of RS with addition of 5.0% MSSPS treated by 170 MPa was 6.1%, which was 33% higher than RS; the syneresis and hardness of RS decreased (P < 0.05) as the addition amount or modified pressure of MSSPS increases, which indicated that MSSPS could improve freeze-thaw stability and texture quality such as hardness during the storage of RS.The RS sample with addition of MSSPS retrograded for 7 d at 4 ℃ appeared to cause a thickening of matrix walls, and an increase in pore size and number of honeycomb texture, which demonstrated by microscopic structure that MSSPS inhibits syneresis and improves the freeze-thaw stability.These results show that MSSPS has a significant influence on the physicochemical properties of RS, and MSSPS can improve the appearance acceptation and texture quality of RS by increasing its freeze-thaw stability and clarity.

Liposomes have proven to be promising carriers for their special structure and characterization, and can be widely used in pharmacy and cosmetics.Supercritical reverse phase evaporation (SRPE) is a new technique for preparing liposomes with supercritical fluid instead of organic solvent.The process has characteristic of simple and high coating ratio for water-soluble substances.The technique was used to prepare liposomes with water soluble glucose, and the effects of the process parameters on the particle size and the coating ratio of liposomes were investigated in detail.The liposomes with an average volume diameter of 290-330 nm were successfully prepared by this technique and the coating ratio for water-soluble glucose was as high as 41.3%.It is confirmed that the temperature, pressure and equilibrium time have great effects on the particle size and the coating ratio.As the pressure increased from 10 to 30 MPa, the particle size first decreased remarkably and then kept approximately constant, while the coating ratio gradually increased to 25.7%-27.5% and then gradually decreased; as the temperature increased from 35 to 65 ℃, the particle size decreased obviously to its minimum value and then gradually increased, while the coating ratio increased all along, even to 41.3%.With the equilibrium time increasing from 15 to 45 min, the particle size kept relatively stable, while the coating ratio increased remarkably; when the equilibrium time exceeded 45 min, the particle size increased remarkably, while the coating ratio decreased remarkably.

Effects of high hydrostatic pressure (550 MPa/5 min/ambient temperature), thermal process (90 ℃/1 min) and high temperature with short time (110 ℃/8.6 s) treatment on the quality of cloudy and clear strawberry juice were investigated.The viscosity, pectin, cloud and cloudy stability of cloudy juice showed no significant change after HHP treatment, while those of TP and HTST juice significantly decreased.Ascorbic acid in HHP cloudy and clear juice reduced by 11.09% and 13.59%, and it decresaed by 7.75% and 10.73% in juices treated by HHP combined with blanching.The loss rates of ascorbic acid in TP and HTST-treated cloudy and clear juice are higher, which are 28.86%-38.89% and 20.38%-29.02%, respectivity.Monomeric and polymeric anthocyanins, total phenols, DPPH and FRAP in HHP cloudy and clear juice well retain.The monomeric anthocyanins and antioxidant activity of juices treated by TP and HTST significantly decrease, while the PC and PPC significantly increase, and total phenols do not change.The color parameters includingL^*, a^*, b^*, C^*and h_ab exhibite no significant change, and the L^* and a^* values of TP and HTST juices significantly decrease.