Abstract:A new shock initiation measuring system is developed with the reverse-impact method， in which the explosive sample was driven by a gas gun and impacted the LiF window at a certain speed. The photonic Doppler velocimetry （PDV） was used to measure the interfacial particle velocity profile between the explosive sample and the LiF window. This measuring system has higher accuracy （3%）， higher time resolution （5 ns） and lower requirement of explosive samples than previous shock initiation measuring methods. Moreover， to explore the effect of aluminum powder， the shock initiation characteristics of three RDX-based aluminized explosives （RDX/Al） with different contents of aluminum powder （0， 15% and 30%） were investigated by this measuring system. The experimental data indicates that with the same impacting speed， the shock initiation reaction growth becomes slower with a higher content of aluminum powder. The interfacial particle velocity of the RDX-based aluminized explosive with 30% aluminum powder requires more time to arrive at a peak value， which is 47% longer than that of the RDX explosive. The aluminum powder makes the shock sensitivity significantly decrease and it plays a dilute role in explosive energy during the shock initiation process of aluminized explosives.

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:To investigate the temperature effects on fracture behavior of HMX-based polymer bonded explosives （PBX） under quasi-static loading， the digital image correlation method （DICM） and crack propagation gauge （CPG） testing system were used in quasi-static fracture tests of the semi-circular bending （SCB）. The fracture characteristics， fracture resistance， damage tolerance and crack unstable propagation rate of HMX-based PBX at different temperatures （25 to 65 ℃） were studied. The results show that with the increase of temperature， the fracture characteristics of HMX-based PBX gradually transform from brittle fracture to ductile fracture， the fracture toughness which indicates the crack initiation resistance significantly decreases， and the damage tolerance is slightly improved. Under the brittle fracture condition of SCB， the crack unstable propagation rate shows a slow-fast-slow law on the propagation path， with a maximum rate of about 370 m·s^-1. The increase in temperature leads to some reduction in the crack unstable propagation rate.

Abstract:In order to study the relationship between impact sensitivity （IS） and molecular structure of nitrogen-rich energetic ionic salts，the configuration optimization and quantum chemical parameter calculation of 21 kinds of energetic ionic salts were carried out at the M06-2X/6-311++G（3df，3pd） level， in which the energy of the highest occupied molecular orbital （E_HOMO）， the energy of the lowest unoccupied molecular orbital （E_LUMO）， the total dipole moment （μ）， the polarizability （α）， the oxygen balance （OB）， the Nuclear Independent Chemical Shift （NICS）， the available free space （ΔV）， the variance of electrostatic potential value on the van der Waals molecular surface （σ²）， the ionization potential （I） and the electron affinity （A） were used as descriptors. The quantitative structure-property relationship study （QSPR） between these descriptors and IS， with the correlation coefficient and root-mean-square error were 0.98 and 0.11， respectively， was built by principal component analysis （PCA） combined with support vector machine （SVM）. The QSPR was used to predict the IS of six newly designed nitrogen-rich energetic ion salts. It is found that the impact sensitivity of the three energetic ion salts （17-35 J） designed based on bis-heterocycle-substituted 1，2，3-triazole （HTANFT） is higher than that of the traditional explosive TNT （15 J）， which indicates that the three energetic ion salts designed based on HTANFT are potential ideal insensitive energetic materials.

Abstract:To figure out the coating mechanism of polymer bonded explosives （PBXs） prepared by spray drying and the effects of binders types and contents on the performance of PBXs， refined 1，1-diamino-2，2-dinitroethylene （FOX-7） and FOX-7 based PBXs with different binder types and contents were prepared by spray drying at the presence of poly ester urethane elastomer （Estane 5703）， fluororesin （F₂₃₁₄）， fluorine rubber （F₂₆₀₂） and acrylic rubber （ACM） as binders， respectively. The surface morphology， crystalline states ， thermal decomposition properties and impact sensitivity of the samples were characterized by field emission scanning electron microscopy （FE-SEM）， X-ray diffractometer （XRD）， differential scanning calorimeter （DSC） and impact sensitivity instrument， respectively. The results indicated that the crystalline state of the resulting samples was α-type. The FOX-7 based PBXs composited by Estane 5703 had the best sphericity， surface smoothness and mechanical safety， while the apparent activation energy decreased by 10.61%. The PBXs composited by F₂₆₀₂ exhibits satisfactory thermal stability. Both binders can effectively reduce the impact sensitivity of FOX-7. When the compounded binders containing Estane 5703 and F₂₆₀₂ at the mass ratio of 4∶1 content was 3%-5%， the surface of FOX-7-based PBXs particles is smooth and the adhesive effect is attractive. When the compounded binder content was 5%， the resulting FOX-7-based PBXs possess excellent safety performance. The compositing structure and desensitization mechanism of binders in PBXs obtained by spray drying were analyzed from the microscopic morphology of FOX-7 in molten state. And the comparative analysis of impact sensitivity， atomic ratio of surface elements and chemical state changes between refined FOX-7 and resulting PBXs was carried out to verify them.

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:In order to treat the acidic washing water in the industrial production， heterogeneous photo-fenton degradation-blowing off is proposed. Firstly， the magnetic catalyst Fe²⁺-Fe₃O₄@AC was prepared by coprecipitation-impregnation. Then，the degradation of NTO in the washing water （about 4 g·L^-1） with system （UV/Fe²⁺-Fe₃O₄@AC/H₂O₂） was studied. pH， addition of H₂O₂ and catalyst concentration were screened to obtain the best conditions. Five repeated experiments were carried out to study the catalyst stability. The importance of conditions， free radical quenching experiment and the EPR spectrum results were studied to speculate on a possible degradation mechanism. In the process of degradation under optimal conditions and blowing off， the change of COD and NH₃-N were recorded.The results show that this system can degrade NTO efficiently. When pH is 2， n_H2O2∶n_NTO is 5 and catalyst concentration is 1 g·L^-1， 99% of NTO can be removed in 150 min. The catalyst has good stability and the NTO removal rate can still reach 82% after 5 cycles. The removal rate of COD and NH₃-N are both 99% after degradation and blowing-off.·OH and ·O₂^- make a contribution to degradation and ·OH plays a major role.

Abstract:Triazole-based energetic compound is a new class of energetic materials with the features of high heat of formation， high nitrogen content and good thermal stability. In this paper， the latest research achievements on synthesis of more than 40 series of energetic compounds based on mono-triazole， bis-triazole， pyrazole-triazole， oxadiazole-triazole and tetrazole-triazole were reviewed， and the performances of some compounds were introduced in detail. It is showed that designing new triazole-based energetic compounds based on structure-performance relationship and balancing energy and safety are the effective strategy to develop high energy and insensitive energetic compounds. On this basis， design and synthesis of cage triazole-based energetic compounds are the promising developing direction. The application study of existing triazole-based energetic compounds with outstanding overall performance is proposed.

Abstract:The introduction of fluorodinitromethyl group into energetic molecules can not only improve oxygen balance， density and explosive performance， but also increase thermal decomposition temperature and reduce sensitivity. The construction of energetic compounds containing fluorodinitromethyl groups has become a hot research topic in the field of high energy dense and insensitive materials. By reviewing the energetic compounds containing fluorodinitromethyl groups in the past two decades， we analyzed and compared the molecular structures， summarized the synthesis methods of fluorodinitromethyl-containing compounds， physicochemical and explosive properties of these compounds， providing some references for the molecular design and synthesis of novel fluorodinitromethyl substituted compounds.