Abstract:In order to investigate the effect of aggregation structure on the properties of hexanitrohexaazaisowurtzitane/octogen （CL?20/HMX） co?crystal， the droplet confined crystallization was used to prepare spherical CL?20/HMX co?crystal. The morphology and structure of the samples were characterized by field emission scanning electron microscopy （FE?SEM）， X?ray powder diffraction （XRD） and fourier transform infrared spectroscopy （FT?IR）. The properties of the samples were analyzed by thermal analysis， sensitivity and combustion tests. The results show that the spherical CL?20/HMX co?crystal was successfully prepared by this method. The diameter of the spherical CL?20/HMX co?crystal is 1.3-1.85 mm， the hollow ratio is about 40%， and the specific surface area is 6.890 m2·g-1. The exothermic peak temperature of spherical CL?20/HMX co?crystal is located at 245.8 ℃ ， the thermal decomposition activation energy （463.02 kJ?mol-1） and the critical temperature of thermal explosion （241.28 ℃） are higher than those of flake CL?20/HMX co?crystal， exhibiting the excellent thermal stability of spherical CL?20/HMX. The impact sensitivity is better than that of raw material and flake CL?20/HMX co?crystal， and the friction sensitivity falls between raw CL?20 and HMX， but lower than that of flake CL?20/HMX co?crystal. The ignition delay time is less than 8 ms and the combustion is efficient and stable， while the flake CL?20/HMX co?crystal， raw materials and their physical mixture exhibit flameless combustion.The construction of millimeter?sized hollow spheres for CL?20/HMX co?crystal has significantly improved the thermal stability，sensibility and combustion performances.

Abstract:A lateral annular slit charge was proposed in order to improve cutting effect in hard rock tuunels. Firstly， the blasting effects of the charge were analyzed theoretically. Then， the distributions of blasting strain and blasting crack after the charge blasting were studied through the model experiments. Finally， field tests were implemented to explore the applied efficacy of the charge. Results showed that the lateral annular slit charge could induce an energy accumulation effect at the slit position， which results in the rock mass at the slit position being subjected to stronger blasting loads and thus having stronger crack propagation ability. The lateral annular slit tube could reduce the blasting strain in the non-slit direction and increase the blasting strain in the slit direction. The strain distribution characteristic proves the energy accumulation phenomenon in the slit direction of the lateral annular slit charge. According to the macroscopic crack propagation， the crack propagation ability of lateral annular slit charge in the slit direction has been significantly improved. Compared with conventional column charge cutting blasting technique， the lateral annular slit charge cutting blasting technique could improve drivage efficiency and reduce cost in hard rock tunnels， which verifys that the lateral annular slit charge is preferred in hard rock tunnel cutting blasting.

Abstract:Using droplet microfluidics technology， an aqueous solution of the active agent at a concentration of 0.5% was used as the continuous phase， and an ethyl acetate solution of DAAF was employed as the dispersed phase. DAAF/F2602 composite microspheres were prepared by fluid-focused microchanneling. The effects of two-phase flow rate ratio， concentration of dispersed phase， and type of active agent on particle morphology， particle size， and roundness of DAAF/F2602 composite microspheres were investigated. The optimal process conditions， including a suspension concentration of 4%， a two-phase flow rate ratio of 16∶1 and an active agent of CTAB， were obtained and compared with the aqueous suspension method. The results show that the DAAF crystalline shape of the samples obtained from two preparation methods are unchanged， the impact sensitivity is higher than 100 J， and the friction sensitivity is 0% and the friction sensibility are more than 360 N， indicating that the two samples have good safety performance. Among them， the particle sizes of DAAF/F2602 composite microspheres which obtained by the droplet microfluidization method were in the range of 20.22 to 53.85 μm， which were smaller than that obtained by the aqueous suspension method （121-356 μm）.Furthermore， the particle sizes distribution was observed to be more uniform. Thethermal decomposition exhibited a delayed peak temperature by 6.45 ℃， and the activation energy was increased by 6.12 kJ·mol^-1， which lead to improved thermal stability. The cone angle generated by the stacking of DAAF/F2602 composite microspheres which obtained by the droplet microfluidization method， is 34°. This angle is smaller than that of composite particles obtained by the water suspension method （40°）， which indicate better dispersion property.

Abstract:In order to characterize the mechanical response of double-base propellant， the viscoelastic properties and constitutive model of double base propellant were studied. Firstly， the viscoelastic properties of double-base propellant were investigated by tensile， compression and stress relaxation experiments with an observation of fracture surface. Then， a hyperelastic-viscoelastic model of double base propellant was established based on the Reduced Polynomial（N=5） model and Prony series. The parameters of the developed model were obtained by the experimental data. Finally， the hyperelastic-viscoelastic model of double base propellant was verified. The relatively error between the results of the simulation calculated by the hyperelastic model and the experiment for uniaxial tensile stress-strain is less than 5.01%. The relatively error between the results of simulation and experiment for stress relaxation is less than 6.49%. The developed hyperelastic-viscoelastic constitutive model of double-base propellant can well describe the mechanical properties of double base propellant， which provides a significant method for the research of mechanical properties of propellant.

Abstract:In order to understand the effect of initial free cavity on the violence of confined octogen （HMX）-based PBX-3 in slow cook-off， the weak restricted test setup was designed with initial free cavity volume ratios of 1.0% and 7.4%， respectively， referring to Sandia instrumented thermal ignition（SITI）. The confined HMX-based PBX-3 explosives were heated at the same rate in slow cook-off tests. The temperatures of different locations at the center plane of explosive and shell surface were acquired using small-sized K type thermocouples， the shell velocity after thermal explosion was measured using the heat-resistant probe of photonic-Doppler-velocimeter（PDV）， and the wreckage of test setup was recycled in the slow cook-off chamber. The results show that the confined PBX-3 explosives are ignited in the center region for the same restricted strength and heating process， no matter with the initial free cavity volume. When the initial free cavity volume ratio is 1.0%， the shell surface temperature and the overall temperature of the explosive are higher when thermal explosion occurs， the shell accelerates faster and the maximum velocity is higher after thermal explosion， the wreckage fragments of test setup are smaller， and the reaction violence is higher. It is analyzed when the initial free cavity volume ratio is 1.0%， the stress of explosive is larger before thermal explosion， resulting in more serious damage. When thermal ignition occurs at the center of the explosive， the larger thermal stress causes a higher pressure induced by the gas accumulation， and the burning rate of explosive is higher. The high-temperature gas generated by the combustion is easier to enter the microcracks， resulting in stronger convective burning， faster pressure growth rate and more violent reaction.

Abstract:The matrix explosives in cast explosives are molten when being ignited under thermal stimulation， thus the hot gas released by reaction expands and reacts in liquid explosives in the physical form of bubble clouds. Considering the scale distribution and activated developing mechanism of burning-bubble clouds， a regulation model for the evolution of burning-bubble clouds after ignition of cast explosives is established. This model well reflected the dependence of reaction evolution and final reaction violence on intrinsic burning rate， shell confinement strength， charging structure size， reserved air-gap volume and pressure relief venting area. Furthermore， the flexibility of this model was verified by comparing the calculated results with the experimental data. Results show that with the increase of shell confinement strength and charge size， the self-sustaining enhanced combustion and reaction violence level increase. Moreover， with the combined design of pressure relief structure venting threshold and pressure relief venting area， the reaction violence of the charge is controlled. Under the charging condition in this paper， when the ratio of pressure relief venting area to shell surface area is up to 8.6‰， the charge reaction violence level is controlled as burning. This work provides a theoretical basis for the thermal safety design and reaction violence evaluation of explosives.

Abstract:To improve the stability of aluminum hydride （AlH₃）， three kinds of embedded-coated AlH₃@Al@xAP（AHAPs） energetic composite particles were prepared by the combination of using acoustic resonance and spray drying technology. The mass ratios of AlH₃@Al and AP were 9∶1（AHAPs-10%）， 7∶3（AHAPs-30%）， and 1∶1（AHAPs-50%）， respectively. The morphologies and structures of the AHAPs and their condensed combustion products were characterized by SEM， EDS， and XRD. The thermal reactivity and stability of the prepared samples were comparatively studied by TG-DSC analysis and vacuum stability tester （VST）. Results show that AHAPs energetic composite particles could not only improve the stability of AlH₃ but also promote the decomposition of AP. With the increase of AP content， the initial decomposition temperatures of AlH₃ are increased by 8.5-11 ℃， and the peak temperature at high-temperature decomposition stage of AP is decreased by about 80 ℃. Compared with the total decomposition time of pure AlH₃（1006 min）， the decomposition time of AHAPs-50% composite particles extend to 1518 min， which corresponds to a 50.9% increment. In addition， the reaction heat of embedded-coated composite particles AlH₃@Al/63.5% AP reaches 9125.6 J·g^-1， which is 1054.1 J·g^-1 higher than that of mechanically mixed samples， and the particle sizes of the condensed combustion products appear to be finer， indicating that their combustion become more complete and the combustion efficiency is greatly enhanced.

Abstract:In order to explore the droplet ignition characteristics of a new type of hydroxylamine nitrate（HAN）-based liquid propellant EMP-01， a droplet electric ignition experimental platform was built by placing the droplet in a hemispherical groove and inserting the electrode. The electrical ignition characteristics of EMP-01 droplets under the conditions of droplet diameter of 6.5 mm， electrode spacing of 0.5 mm and voltage loading rate of 86.31 V·s^-1 were studied， and the ignition delay time under this condition was determined. At the same time， the variation law of droplet ignition delay time and combustion process was also studied within 34.20-246.37 V·s^-1 under the condition of constant droplet diameter and electrode spacing. The results show that the droplet separation of EMP-01 undergoes three stages： heating， thermal decomposition and combustion， and there is a periodic expansion and contraction process in the thermal decomposition stage. When the voltage loading rate is 34.20 V·s^-1， the EMP-01 droplet cannot be successfully ignited； When the voltage loading rate is 49.49-246.37 V·s^-1， the ignition delay time decreases gradually with the increase of voltage loading rate， but with the increase of voltage loading rate， the decrease rate of ignition delay time gradually slows down.

Abstract:Limited by the size of model test chamber， the reflection wave generated by explosion load on the boundary of test chamber would inevitably affect the expected results in the centrifugal tests of underwater explosion. Therefore，reducing the boundary effect will substantially restore the actual test situation and improve the test accuracy. Numerical simulation on centrifuge model test of underwater explosion was conducted based on the Coupled-Eulerian-Lagrangian（CEL） method，. Through comparing experimental results with theoretical results and analyzing mesh sizes of 1， 2， 4， 6， 8 and 10 mm， the reliability of the numerical model was verified. Based on that， the shock wave propagation characteristics in centrifuge tests of underwater explosion with boundary energy absorbing materials of rubber and foam （thicknesses of 5， 10， 15 and 20 mm） were compared， and the mechanism of wave absorption and energy dissipation was analyzed. The results show that the Euler mesh size of 2 mm could balance the calculation efficiency and accuracy of calculation results. Laying rubber or foam materials on the inner wall of the model chamber could effectively reduce the reflection effect of underwater explosion shock waves. The rubber material is more effective in shock wave absorption than the foam material for the condition of 5 mm thickness. However， with the increase of material thickness， the foam material has a better absorption effect than rubber. Both rubber and foam materials have a certain inhibitory effect on low-frequency signals of shock waves， but the inhibitory effect on high-frequency signals is weak.

Abstract:To study the jet formation and failure characteristics of penetrating concrete and rock targets of shaped charge with large barrier， the jet formation by using X-ray cinematography and static armor-piercing into concrete and rock targets were carried out. Meanwhile， the evolution process of detonation wave， the rod jet formation of shaped charge with large barrier and penetration process of concrete and rock targets are simulated by ANSYS/AUTODYN software. Combined with the experimental results， the penetration damage characteristics of the shaped charge rod jet to concrete and rock targets were analyzed. Results show that the Lee-Tarver equation of state can accurately describe the propagation process of the internal detonation wave， and the maximum error of forming jet parameters （projectile length， jet length， jet head velocity and jet diameter） is 12.8% compared with the test. The continuous rod-like jet with large aspect ratio can be formed after detonation of the shaped charge with large barrier. There are obvious craters in the penetrated concrete and rock targets， and the jet has no obvious reaming effect during the penetrating concrete process. The penetration depth and hole diameter of the penetrated concrete target are 46.7% and 48.1% larger than those of rock target in the test. However， the surface of the rock target is seriously damaged and the crater area is larger. Compared with the concrete target， cracks in rock target are continuously generated and developed significantly in the process of jet penetrating and the length and width of cracks formed are larger than those of concrete targets. The damage range around the rock target penetration channel is larger， and the internal damage of the target is serious.

Abstract:Refined 3-nitro-1，2，4-triazol-5-one （NTO） product were prepared by spray drying technology to improve the morphology and reduce the particle size. Acetone was used as the experimental solvent. The effects to inlet temperature， inlet flow rate， feed rate and precursor mass concentration on the morphology and particle size of the refined NTO were investigated， and the optimal spray drying process parameters was selected. The surface morphology， molecular structure and thermal stability of refined NTO products were characterized by scanning electron microscopy （SEM）， X-ray diffraction （XRD） and fourier transform infrared spectroscopy （FT-IR）， and synchronous thermal analyzer （TG-DSC）. The results show that the sphere-like NTO with good morphological， stable crystal structure， narrow particle size distribution range and an average particle size of 1.2 μm can be obtained when the inlet temperature is 60 ℃， the inlet gas flow rate is 357 L·h^-1， the feed rate is 3 mL·min^-1， the NTO precursor concentration is 16.57 mg·mL^-1. Compared with the feedstock， the thermal decomposition activation energy of the refined NTO was enhanced by 41.7 kJ·mol^-1， and the thermal explosion critical temperature was increased by 10.4 ℃， which has better thermal stability.

Abstract:In order to obtain super thermite with spherical core-shell structure for 3D printing of energetic materials， Al_2#@CuO and Al_2#@Bi₂O₃ super thermites possessing highly spherical core-shell structure were prepared by spray granulation method for directly coating solid particles. The influence of construction parameters （particle size ratio and solid content） on particle size of super thermite was studied by using NanoMeasure statistical software. The spherical core-shell structure was characterized by scanning electron microscopy and X-ray diffraction. The flowability of super thermite was characterized using the angle of repose method. The ignition characteristics were observed using high-speed cameras. The results show that two types of super thermite possessing highly spherical core-shell structure were prepared using construction parameters of solid content 25%， 2# aluminum powder， and nano metal oxide （CuO， Bi₂O₃） particle size. The structure was an ideal spherical core-shell structure， with an average particle size of about 40 μm. The average thickness of the shell is 7.79 μm （Al_2#@CuO-25%）， 10.47 μm（Al_2#@Bi₂O₃-25%）. Compared with the mechanically mixed sample， the flowability of super thermite with spherical core-shell structure displays a great improvement. The angle of repose of Al/CuO system reduces from 48.8° to 22.9°， and the angle of repose of Al/Bi₂O₃ system decreases from 37.3° to 16.6°. The combustion time of Al_2#@CuO super thermite with spherical core-shell structure increases from 100 ms to about 0.9 s， indicating that microstructure variation has an impact on its combustion characteristics.

Abstract:To study the safety of pulse excitation of hot bridge wire EED， we established a numerical model for the temperature rise of the hot bridge wire EED， and the ignition criterion of hot bridge wire EED was obtained. Based on the above， we designed the calculation procedure for the critical ignition current of the hot bridge wire EED and revealed the influence of single pulse and pulse train current excitation parameters on the critical ignition current of hot bridge wire EED. The results showed that under single pulse excitation and when the pulse width was less than 5 μs， the ignition energy of the hot bridge wire EED was fixed， which suggested that the bridge wire-reagent system was in an adiabatic state. So the ignition state was related to the energy input to the bridge wire. However， when the pulse width was greater than 15 ms， the critical ignition current of the hot bridge wire EED was fixed. So the ignition state was related to the electric power of the bridge wire. Another difference was that under narrow pulse train current excitation， the time constant of the curve for critical ignition current with repetition period was independent of the pulse width. Furthermore， when the repetition period was greater than 1.25 ms， the bridge wire-reagent system exhibited no thermal accumulation effect， and the critical ignition current was the same as the single pulse current excitation. However， when the repetition period was lower than 1.25 ms， the bridge wire-reagent system exhibited the thermal accumulation effect， which resulted in rapid decrease of the critical ignition current as the repetition period decreased.

Abstract:To search green， low-toxicity lead-free primary explosive， a new tetrazole derivative ligand 1H-5-acylhydrazide tetrazole （TZCA） and its complex Ni（TZCA）₂（ClO₄）₂ （ECCs-1） were synthesized by hydrazinolysis and coordination reactions using ethyl 1H-tetrazole-5-carboxylate as the raw material. The molecular structure and thermal decomposition properties of the title complex were tested by X-ray single crystal diffraction， IR diffraction， NMR， elemental analysis， thermogravimetric and simultaneous thermal analyzers. The heat of combustion of ECCs-1 was tested by oxygen bomb calorimetry and its energy parameters were predicted based on Hess law and K-J equation. Sensitivities of ECCs-1 were tested by BAM test methods. The results show that the density of TZCA is 1.83 g·cm^-3， monoclinic crystal system， C2/c space group， the stacking mode is V-staggered stacking. The density of ECCs-1 powder is 1.90 g·cm^-3， impact sensitivity is 17 J， friction sensitivity is 72 N， thermal decomposition temperature is 336 ℃， activation energy of the thermal decomposition reaction is 183.3 kJ·mol^-1， thermal explosion critical temperature is 309.8 ℃， activation entropy is 46.745 J·K^-1·mol^-1， and the activation enthalpy is 178.563 kJ·mol^-1. The hot baking and lead plate tests both show that ECCs-1 has a good detonation performance.

Abstract:In order to explore the effect of biodiesel on the thermal decomposition characteristics and vibration resistance of on-site mixed emulsion explosives， the microscopic structure， thermal decomposition characteristics and vibration resistance of the matrix samples of on-site mixed emulsion explosives with biodiesel as the oil phase material were studied by laser particle size analyzer， optical microscope， synchronous thermal analysis technology， vibration experiment and water dissolution method， in which the mass contents of biodiesel were 0%， 1%， 2% and 3%， respectively. The results show that the average particle size of the on-site mixed emulsion explosive matrix samples with biodiesel is smaller， the uniformity of the internal phase particles is better， and the average particle size and dispersion index are reduced by 12.9% and 38.0% respectively， compared with the sample without biodiesel. When the mass content of biodiesel in the sample is 3%， the initial temperature， peak temperature and activation energy of the decomposition reaction are reduced by 5.8%， 3.7% and 12.3%， respectively， compared with the in-situ mixed emulsion explosive matrix sample without biodiesel， indicating that the thermal stability is reduced. The anti-vibration performance of the on-site mixed emulsion explosive matrix sample with 3% biodiesel is the worst. The dissolution loss rate increases from 0.117% to 0.313% after 6 vibration periods， and the crystallization phenomenon appears after 4 vibration periods. The on-site mixed emulsion explosive matrix sample with 1% biodiesel has the best anti-vibration performance. After 6 vibration periods， the dissolution rate increases from 0.070% to 0.197%， and no crystallization occurs. When the content of biodiese is 1%， the average particle size of the internal phase is small， the distribution uniformity is good， the thermal safety is high and the vibration resistance is the best.

Abstract:To study the fuel dispersion and detonation process at a falling speed of 1000 m·s^-1， a computational simulation model of fuel dispersion detonation was established， and the static fuel dispersion and cloud detonation experimental results were used as numerical methods to verify the results. Results show that under the condition of a falling speed of 1000 m·s^-1， the distribution of cloud shape and concentration field with time and space is obtained by numerical simulation. The cloud shape is roughly fan-shaped， and the concentration gradually decreases with distance， and finally reaches a stable distribution. The radial radius of the cloud can reach 2.24 m. The law of the cloud detonation process and the influence of the detonation pressure field and temperature field are obtained. After initiation， the arc-shaped wave front is formed and diffuses outward， and the temperature and pressure continue to decay. The numerical simulation results are consistent with the experiments， which provide a new way for the safety design of the high-falling velocity cloud explosion weapon system.

Abstract:In order to explore the processing parameters for the continuous production of double-based spherical propellants with particle sizes in the range of hundred microns， a Co-axial flowing microfluidic installation was used to process the dispersed phase of a 10 % double-based propellant solution and prepare the double-based spherical propellants with a controllable particle size in the range of 400-700 μm. The effects of two-phase flow ratio（Q_c/Q_d） and chip size on the morphology and particle size of double-based spherical propellants were investigated. Moreover， the morphology， particle size distribution， and constant volume combustion performance of samples were characterized using scanning electron microscopy， optical microscope， and closed bomb test，respectively. Results show that， the median particle size （D₅₀） of the samples prepared into the same type of chip increases first and then decreases with the decrease of two-phase flow ratio. As the internal diameter of the continuous phase or the dispersed phase channel increases， the D₅₀ of the samples obtained at the same two-phase flow ratio increases successively. When the internal diameter of the continuous phase and the dispersed phase channels are 2 and 0.85 mm， and the two-phase flow ratio is 200.00， the resultant sample displays high monodispersity， smooth surfaces， dense inside， regular spherical shapes （average sphericity φ_K=0.949） and narrow size distribution （span=0.09）. Its D₅₀ is 539.94 μm， and the average particle density is 1.601 g·cm^-3. In the closed bomb test， the pressure-time curve shows that the samples with two varied packing densities （Δ₁=0.12 g·cm^-3， Δ₂=0.20 g·cm^-3） can burn stably， and the dynamic vivacity-relative pressure curve follows the regressive burning law of the dense spherical propellants.

Abstract:To explore low sensitivity and environmental-friendly energetic combustion catalysts， three new energetic copper complexes， ［Cu（NH₃）₄（DN）₂］， ［Cu（IMI）₄（DN）₂］， ［Cu（ATO）₄］（DN）₂ were synthesized. Ammonium dinitramide （ADN） was used as a precursor to prepare dinitramide acid （HDN） by ion exchange reaction， and the resultant solution reacted with basic copper（Ⅱ） carbonate continually to produce copper（Ⅱ） dinitramide， which reacted further with nitrogen-rich ligands （ammonia， imidazole， 4-amino-1，2，4-triazole-5-one）. The structures of the three complexes were characterized accurately by X-ray single crystal diffraction， infrared spectroscopy and elemental analysis. Their thermal stability， hygroscopicity， sensitivities toward impact （IS）， friction （FS） and electrostatic discharge （ESD） were investigated. Furthermore， the effect of ［Cu（IMI）₄（DN）₂］ towards the burning rate of propellants were performed. Results show that the thermal stability of three complexes can meet the application requirement of solid propellants， and the initial decomposition temperatures are all higher than 140 ℃. The hygroscopicity of the complexes were improved obviously， which could be as low as 2%-5% of the precursor ADN. ［Cu（IMI）₄（DN）₂］ has the lowest sensitivity （IS 28.6 J， FS 0%， ESD 185 mJ） of the three complexes. With 4% of ［Cu（IMI）₄（DN）₂］， the burning rate of the basic formula propellants was increased by 27.7%， which was expected to be used as low sensitivity burning rate catalyst in high burning rate solid propellants.

Abstract:In order to achieve the high safety of ignition device and micro package volume， a MEMS ignition device has been designed with a double-layer barrier electro-thermal safety and arming device in this work. The device is of three core components including an igniter， a safety and arming device， and an ignition powder， all of which are assembled linearly within an overall size of Φ10 mm×3.3 mm. The S&A device has a double-layer structure with bistable function. The frontend initiator， which is fabricated on a ceramic circuit board， is a NiCr bridge foil to be covered with an Al/CuO energetic film. The two pads from the circuit board lead the bridge foil electrode to the backend device， there by reducing the package volume of the sequence. BPN is selected as the ignition powder in the device. According to the safety and arming function test， the ignition device can prevent the igniter from lighting the ignition powder in safety condition， when the size of the Al/CuO is set to Φ800 μm×30 μm. Otherwise， the BPN ignition powder can be ignited in arming condition.

Abstract:The planar thin film transducer chip was designed with longitudinally integrated PN junction structure diode， and integrated through microelectronics technology for excellent security performance and high integration characteristics. Each of three different-sized chips with 1.0 mm×1.0 mm，1.5 mm×1.5 mm and 2.0 mm×4.0 mm， were designed under four breakdown voltages of 8， 18， 28， 34 V， and two kinds of resistance ，3 Ω and 4 Ω. The ignition tests were carried out on the integrated chip to study the impact of the integrated structure on the burst performance of the transducer. Results from the static electricity of these chips show that the larger the size of the integrated thin film chip is， the stronger the antistatic ability， the greater the resistance in the bridge area of the chip， and the more vulnerable to electrostatic interference are. The electrostatic protection performance of designed chip can reach 500 pF/500 Ω/25 kV. The smaller the breakdown voltage is， the greater the bypass current capacity， the greater the impact on the burst performance of the transducer， and the greater the breakdown voltage， but the smaller the electrostatic protection effect are on the energy converter. For initiating explosive devices to be ignited under 33 μF/16 V， the integrated chip with an 18V breakdown voltage should be selected. Therefore， when the integrated thin film chip is applied， it is necessary to select an appropriate breakdown voltage according to the working voltage of the transducer for both a protection against static interference and a necessary avoidance in failure of its normal function.

Abstract:The polymorphic transformation （PT） and control technology of hexanitrohexaazaisowurtzitane （CL‍-20） has been a hot area of research in energetic materials， which is also the key issue must be addressed to promote its application. In order to further understand the PT characteristics and mechanism of ε‍-CL‍-20 with different crystallization characteristics， the PT laws and isothermal PT kinetics of ε‍-CL‍-20 were studied based on in‍-situ X‍-ray powder diffraction （XRD） technology. The effect of surface and internal defects on the ε→γ PT behavior of CL‍-20 was discussed. The isothermal PT kinetics of ε‍-CL‍-20 with different crystallization characteristics was analyzed and the related parameters were calculated. The results show that temperature is the dominant factor affecting the solid‍-solid PT of ε‍-CL‍-20. For the conventional particle ε‍-CL‍-20， with the increase of internal and surface defects in the crystal， the initial temperature of PT decreases and the PT rate increases. Compared with 100 μm CL‍-20， ultrafine （0.5-1 μm） ε‍-CL‍-20 has higher starting temperature of PT， but its PT rate is also faster. The abnormal PT behavior of ultrafine ε‍-CL‍-20 is explained from the two‍-sidedness of crystal defects. When CL‍-20 undergoes ε→γ PT under thermal stimulation， both the surface and internal defects of the crystal have an induction effect on the PT process， and the γ crystal preferentially nucleates at the defects such as vacancies， impurities or dislocations with low nucleation barrier on the ε‍-CL‍-20 crystal， and then gradually grows up at these positions.

Abstract:In order to explore new energetic material with both good thermal stability and high safety performance， 4，8-di（2，4，6-trinitro-3，5-diaminophenyl）difurazanopyrazine （NADFP） was synthesized by substitution reaction using 1-chloro-2，4，6-trinitro-3，5-diaminobenzene and 4H，8H-difurazanopyrazine as raw materials. Its structure was characterized by nuclear magnetic resonance （¹H and ¹³C spectrum）， infrared spectroscopy and element analysis. The single crystal of NADFP·DMF was obtained by solvent evaporation method， and the crystal structure was determined by single crystal X-ray diffraction. Results show that NADFP·DMF belongs to monoclinic system， space group P2₁/c， a=7.854（3） Å， b=18.466（6） Å， c=11.093（3） Å， ρ=1.640 g·cm^-3. The inter-/intramolecular interactions were calculated by Hirshfeld surfaces analysis with hydrogen bond interactions accounting for 53.5%. The thermal behavior of NADFP was studied by DSC and TG/DTG methods， which show that its decomposition peaks are 337.2 ℃ and 368.8 ℃. The theoretical detonation performances and mechanical sensitivities of NADFP were investigated. The measured density is 1.81 g·cm^-3， the solid formation enthalpy is 827.1 kJ·mol^-1， the calculated detonation velocity and pressure are 7968 m·s^-1 and 36.0 GPa， respectively. The impact sensitivity is above 40 J， and the friction sensitivity is above 360 N. The overall performance of NADFP is obviously better than that of traditional heat-resistant explosive 2，2′，4，4′，6，6′-hexanitrostilbene.

Abstract:Aiming at the problems that the crystallization methods （evaporation， antisolvent and cooling， etc.） of the conventional explosive are difficult to accurately control the uniformity of supersaturation and the low solvent recovery rate， an organic solvent nanofiltration（OSN） membrane crystallization apparatus based on pressure-driven and cross-flow filtration was designed and used to study the membrane crystallization process of 1，3，5，7-tetranitro-1，3，5，7-tetrazacyclooctane（HMX）. The effects of key process parameters （temperature and pressure） on the crystal morphology and particle size were discussed， and the crystal morphology and structure were compared with those of evaporative crystallization. The HMX crystals after recrystallization by both methods were characterized by scanning electron microscopy（SEM），X-ray powder diffractometer（XRD） and thermogravimetric-differential scanning calorimeter（TG-DSC）. The long-term operational stability of the nanofiltration membrane was further investigated， and the solvent recovered by permeation was used to re-crystallize. Results show that by the optimal control of temperature and pressure， the membrane crystallization process can obtain β-phase HMX with narrow particle size distribution （coefficient of variation < 46%）， high crystal density （ρ_avg=1.8997-1.9004 g·cm^-3） and excellent thermal stability. Compared with evaporation crystallization， the supersaturation control in the membrane crystallization process is easier to operate， and the prepared crystal morphology is more uniform. After repeated use， the rejection of HMX molecules in the solvent still remained above 92%， showing a good permeation selectivity stability. The β-phase HMX crystals with an median particle size of 34.92 μm and a coefficient of variation of 37.22% can still be prepared by membrane crystallization using permeation-recovered solvent， indicating that this technology can realize the efficient recovery and reuse of the crystallization solvent.

Abstract:In order to explore the effects of explosive environments on the oxidation and combustion of aluminum nanoparticles （ANP）， the mechanisms of high temperature combustion of ANP in nitroglycerin （NG）， 1，3，5-trinitro-1，3，5-triazine （RDX） and 1，3，5-triamino-2，4，6-trinitrobenzene （TATB） environments under different heating methods were studied by molecular dynamics simulation. The results show that the oxidation capacity of NG， RDX and TATB to ANP reduces in order， and the different explosive environments have different effects on the microscopic mechanism of combustion. As the oxidizability of explosive environment becomes weaker， the degree of ANP crack weakens at rapid heating， and with the oxidation becomes slower， the main coordination number of Al atom in final formed Al cluster decreases from 7 in NG environment to 6 in TATB environment. Besides， the dissociated Al atoms from ANP form some large Al clusters with about 100 atoms in the TATB environment， which also inhibits the oxidation of ANP. There is little difference on the number of Al clusters between different explosive environments at programmed heating. However， the number of Al clusters formed after ANP cracks is less as the oxidizability of the explosive environments decreases at constant heating and adiabatic heating. The number of Al clusters continues to increase in a short time thereafter due to the reason that the small Al clusters are less likely to agglomerate in a weakly oxidizing environment. ANP in NG environment mainly reacts with the oxygen-containing products decomposed from explosives， and the formed Al clusters are oxidized more completely. Nevertheless， ANP could react with N₂， CN and other oxygen-free products in RDX and TATB environments， which leads to the formation of Al clusters containing C， H and N atoms， and thus the oxidation of Al clusters is not complete.