Abstract:Molecular simulation technique was used to study the interaction between HMX and AP molecules. The solubility of AP in dimethyl sulfoxide (DMSO) was determined by weighing method. The solubilities of HMX in pure DMSO solvent and different concentration DMSO solutions of AP were obtained using high performance liquid chromatography (HPLC). The ternary phase diagram of HMX/AP/DMSO at 26 ℃ and normal pressure was obtained through fitting solubility data. Based on the HMX/AP/DMSO ternary phase diagram, the HMX/AP co-crystal was prepared by solvent/non-solvent method and was characterized by scanning electronic microscope (SEM) and powder x-ray diffraction (PXRD). Results show that the morphology of HMX/AP co-crystal is regular long strip and different from the original crystals (HMX, AP). The solubility of HMX/AP co-crystal in water is only 0.034 g/100 mL.

Abstract:The crystallization technology conditions of preparing the Reduced Sensitivity RDX (RS-RDX) by direct nitrolysis of 1, 3, 5, 7-tetraazatricyclo[3.3.1.1^{3, 7}] decane (HA) at the presence of 1-methyl-imidazole nitrate (ionic salt) were studied. The effects of stirring speed, crystallization temperature, amount of ionic salt, and dropping rate of water on the crystalline form of RDX were investigated. The morphology and sensitivity of RDX crystals were analyzed and characterized by scanning electron microscopy (SEM), and impact sensitivity test. The results show that the optimal crystallization technology conditions are the molar ratio of 1-methyl-imidazole nitrate and HA is 0.015, and stirring speed 800 r·min^-1, dropping rate of water 1 drop/40 s, crystallization process temperature 10~70 ℃. The RDX obtained under the optimum conditions is uniform with regular shape like octahedron, and the explosion probability is 17% according to the standardization method of GJB772A-1997-601.1.

Abstract:The green nitrating reaction process of epichlorohydrin (ECH) with dinitrogen pentoxide(N₂O₅) was studied. The effects of catalyst type, reaction temperature, reaction time and solvent on the nitrating process of preparing 3-chloro-1, 2-propylene glycol dinitrate were investigated. Results show that H-ZSM-5 catalyst has good catalytic properties. Under the optimum reaction conditions of H-ZSM-5 as catalyst, dichloromethane as solvent, the reaction temperature 15 ℃, reaction time 6 hours and N₂O₅/ECH molar ratio 1.1:1.0, the conversion of ECH is 100%.The selectivity and yield of 3-chloro-1, 2-propylene glycol dinitrate are 98.0%.

Abstract:A new refining process of 2,6-diamino-3,5-dinitropyridie-1-oxide(ANPyO) was investigated including acylation, recrystallization and deprotection procedures. The influence of different processing conditions on product purity, particle size distribution, impact sensitivity, friction sensitivity and micro-structure were studied and compared with that of refining method with CF₃COOH. Results show that the optimal conditions of new refining method are as following: DMF as solvent for the recrystallization of the intermediate (2,6-diacetamino-3,5-dinitropyridine-1-oxide) and ammonia as the amination agent and amination temperature 50 ℃. Under the conditions, ANPyO was prepared with yield of 90.5%, and the purity of 99.5%. Its properties were characterized with pH of 6.3, melting point of 355 ℃, vacuum stability of 0.01 mL·g^-1, impact sensitivity of 257 cm, friction sensitivity of 2%.

Abstract:4,4′-Bis-1,2,4-triazole (2, BTr) was synthesized from N,N-dimethylformamide azine dihyfrrochloride (1) and 4-amino-1,2,4-triazole in toluene as solvent. The structure of BTr was characterized by ¹H NMR, IR, MS and element analysis. The single crystal of BTr was also cultivated successfully and determined by a X-ray single crystal diffractometer. The effect of reaction solvent, molar ratio, time and temperature on the yield of BTr were investigated. Results show that using toluene as reaction slovent, the optimal conditions of preparation are as follow: molar ratio of 1 to 4-amino-1,2,4-triazole 1:1.2, time 8 h, temperature 110 ℃, the yield is 86.4%. And the crystal of title compound is orthorhombic system, space group Pnma with crystal parameters of a=0.69712(14) nm, b=0.74045(15) nm, c=1.1156(2) nm, V=0.5759(2) nm³, Z=4, D_c=1.570 g·cm^-3, F(000)=280, R₁=0.043, ωR₂=0.1222. The two triazole rings in BTr are vertical to each other, and that should be beneficial to the stability of the molecule due to the least steric hindrance..

Abstract:The absorption spectra of TATB, in the frequency range of 0.2-2.5 THz, were measured by terahertz time-domain spectroscop, and the experimental results show that the characteristic peaks of TATB are located in 1.65 THz and 2.22 THz. The theoretical simulation by density functional theory(DFT) shows that the characteristic peaks of TATB are located in 1.2 THz and 1.65 THz. The experimental results agree with the theoretical calculation results, which show that TATB has distinct characteristic absorption peaks in the frequency range of 0.2-2.5 THz.

Abstract:The 2,2-dinitropropyl acrylate-vinyl acetate (DNPA-VAc) copolymer was synthesized by the free radical polymerization in ethyl acetate using azobisiosbutyronitrile as initiator. The effects of molar ratio of monomers, initiator concentration and time on copolymerization were investigated. The structure and properties of DNPA-VAc copolymer were also characterized by FTIR, ¹H NMR, DSC and TG measurements. Results show that the copolymer is obtained with the yield of 72% under conditions of DNPA and VAc molar ratio of 3:1 at 80 ℃ within 8 hours. The glass transition temperature and thermal decomposition peak temperature of the DNPA-VAc copolymer is 59.7 ℃ and 259.1 ℃. It is compatible with RDX and HMX, and thermal stable.

Abstract:4,5-Bis(1H-tetrazol-5-yl)-1H-imidazole(H₃BTI) is a high-nitrogen azole compound which may be suitable as ingredient for low signal propellant and gas generator. The synthetic technology of H₃BTI was optimized with the yield of 94.6% as following: the molar ratio of 4,5-dicyanoimidazole, sodium azide and ammonium chloride, 2.2:2.2:1, solvent DMF, reaction temperature 90 ℃, and reaction time 8 h. The thermal behavior and non-isothermal decomposition kinetics of H₃BTI were studied with DSC and TG/DTG method. Results show that the kinetic parameters of thermal decomposition reaction, are the activation energy and pre-exponential factor are 197.62 kJ·mol^-1 and 16.16, respectively, and the critical temperature of thermal explosion of H₃BTI is 556.38 K, which indicates that H₃BTI has better thermal stability than that of RDX, and activation entropy, activation enthalpy and activation Gibbs free energy of the thermal decomposition are 35.72 J·mol^-1·K^-1, 193.66 kJ·mol^-1 and 173.33 kJ·mol^-1, respectively.

Abstract:The synthesis of 3,6-dinitropyrazolo[4,3-c]pyrazole(DNPP) was optimized at 100 g level with total yield increase from 9.3% to 17.9%. The structures of intermediates and DNPP were confirmed by IR, ¹H NMR, ¹³C NMR, elemental analysis and MS. The mechanism and safety of cyclization and reduction one pot method were discussed. Freezing crystallization technics, instead of extractive technics, which could avoid organic reagant and shorten operation process, was used to post-process 4-diazonium-3,5-dimethylpyrazole, increasing the yield from 77.0% to 86.1%. The single crystal of DNPP·H₂O was obtained in the water system. The crystal of DNPP·H₂O belongs to monoclinic system, space group P2(1)/c, cell parameters: a=0.3480(4) nm, b=1.4134(16) nm, c=0.9027(11) nm, α=90°, β =94.327(16)°, γ=90°, V=0.4427(9) nm³, Z=4, D_c=1.756 g·cm^-3, μ=0.164 mm^-1, F(000)=240, R₁=0.0503, wR₂=0.1391.

Abstract:The unsymmetric dimethyl hydrazine (UDMH) wastewater was degraded by the microwave (MW) enhanced Fenton, and the effect factors, such as MW power, dosage of H₂O₂, pH, Fe²⁺:H₂O₂ molar ratio on wastewater treatment were studied. The best degradation conditions were determined by the orthogonal experiment. Results show that, the chemical oxygen demand(COD) removal rate could be 98.4% on condition that MW power is 280 W, H₂O₂ (68.5 g·L^-1) dosage 4.0 mL, pH 4.0, Fe²⁺:H₂O₂ molar ratio 1:16 and reaction time 8.0 min.

Abstract:In order to investigate the characteristics of the acoustic radiation induced by the interaction between high-temperature particles (Al₂O₃) and water from the underwater combustion of pyrotechnic composition, the bubble dynamic model was deduced based on heat transfer, mass transfer theory. The bubble radius and its growth velocity were calculated, and the bubble radius calculated and the literature results were compared also. Results show that with the high temperature particle continuous cooling, although bubble radius increases constantly, growth rate becomes slowly, and the calculated results agree well with literature.

Abstract:Aiming at the combustion destabilization during the depressurization of base bleed projectile when propelled out of gun muzzle, a 2D-axisymmetric unsteady model for the combustion flow field of AP/HTPB base bleed propellant was established. The flow field characteristics in base bleed simulator under transient pressure-release were obtained through numerical simulation. Results show that in the pressure-release process, the parameters such as the pressure, the density and the temperature in the combustion chamber decrease quickly along the axial direction, the gas flow rate rises rapidly, and the gradients of various parameters gradually decrease. As a result of the base bleed propellant gas ejecting into the chamber, the density decreases along the radial direction, whereas the temperature increases on the contrary. The calculated pressure varying with time in the combustion chamber agrees well with the experimental data.

Abstract:The ANSYS parametric design language was used to established the mesoscale representative volume element(RVE) model to estimate effective elastic properties including elastic modulus and Poisson′s ratio of explosive B. Results show that the calculated results agree with that from the literature. The influence of particle size distribution on effective elastic properties was also studied, and it can be inferred that the model can predict the effective elastic properties without the particle distribution, and the error between the calculation results and the experimental results is less than 10%.

Abstract:In order to optimize the NMR assignment of 3, 4-dinitrofurazanfuroxan (DNTF), a combination of experimental NMR and computational GIAO-NMR techniques was utilized to distinguish the chemical shifts of ¹³C and ¹⁵N. One dimensional (1D) ¹³C and ¹⁵N NMR analyses were performed using DMSO-d₆, acetone-d₆ and CDCl₃ as solvent. All signals of DNTF were found in DMSO-d₆. In the ¹³C NMR, the chemical shifts were assigned by 2D INADEQUATE NMR experiment. Based on the geometry of DNTF optimized at the DFT-B3LYP/6-311+G(2d, p) level by using Guassian 09 program, the ¹³C and ¹⁵N NMR chemical shifts were calculated by GIAO method at different level, which agree with experimental data. Results show that the electro-withdrawing effect of the O(22) in furoxan cycle leads to large ¹³C chemical shift changes of C(9) and C(13), and makes C(9) appear in higher field than C(13).

Abstract:Cycloaddition reaction HN₃ + NH₂CN → 5-AT has been theoretically investigated by B3LYP, QCISD and MP2 methods with 6-311+G^*basis set. The solvent effects on the geometries, reaction path properties, energies, thermodynamic, and kinetic characters in four solvents (carbon tetrachloride, dimethylsulfoxide, aceton, and water) have been studied by using self-consistent reaction field (SCRF) approach with the polarizable continuum model (PCM). Results show that effects of solvent on the geometric characters and reaction path properties are negligible. The equilibrium constant in dimethylsulfoxide solvent is the largest, so the reaction easier occurred spontaneously in dimethylsulfoxide solvent thermodynamically. The rate constant in the solvents is smaller kinetically than that in gas phase, and 300 to 350 K is the most feasible temperature to the reaction.

Abstract:The mechanical properties of RDX and HMX crystals were investigated by using molecular dynamics simulation method. The fracture properties of the crystals were analyzed with impact test, laser diffraction size analyzer and scanning electron microscope. The results show that the calculated elastic constants and modulus of HMX crystals are higher than those of RDX crystals. The ductibility of RDX crystals is better than that of HMX crystals.Under the same impact condition, both the plastic deformation and fragmentation appear in crystals. The plastic deformation is preponderant in RDX crystals, and the fragmentation is preponderant in HMX crystals and their fracture is much more severe. The molecular dynamics simulation on the mechanical property for different explosive crystals is accuracy and reliability.

Abstract:Tensile mechanical properties of HMX based brittle explosives were investigated by Brazilian test with arc compress head and LVDT, and the difference between the results of the Brazilian test and single-axis tensile test was also analyzed by the t check method. For the brittle PBX-HMX, results show that PBX-HMX′s break strength and break strain tested by arc compress head Brazilian test are very close to that of the single-axis tensile method when the radius ratio of sample to the arc compress head is 1:1.35. Then, mechanical properties of three kinds of casting explosive were obtained at ratio of 1:1.35 by arc compress head Brazilian. The mechanical properties of casting explosive tested by two methods show the same trend and are very close too. So the arc compress head Brazilian test can be used to determinate the tensile mechanical properties of PBX. Howere, the t check analysis shows that there are still some differences between the two methods, the arc compress head Brazilian test can not replace tensile method completely.

Abstract:Influence of different ratios of 1,3,5-trinitrohexahydrotriazine(RDX) to 3,4-bisnitrofurazan-furoxan(DNTF) on the mechanical properties of DNTF/RDX composite modified double-base(CMDB) propellant (DNTF/RDX-CMDB, DFR propellant) was studied by uniaxial tensile test, charpy impact test and dynamic mechanical analyzer.The tensile strength (σ_m), elongation at the maximum stress(ε_m) and impact strength(a_K) of DFR propellant at -40 ℃ were obtained. The dynamical characteristics (viscoelastic coefficients C₁^g) of β -relaxation was acquired by WLF equation according to the "Time-Temperature" equivalence principle. The effect of plasticizer content on the various mechanical properties and change rule of σ_m and ε_m were analyzed, showing that a good correlation between σ_m, ε_m, a_K at low temperature and plasticizer content. The plasticizer content reducing, C₁^g increasing, "free volume of side group of NC molecule" decreasing make the mechanical performances (σ_m and ε_m) worsen.

Abstract:Plasma initiation is an advanced initiating technique that ensures intrinsic safety and high reliability of the initiator, small-scale bridge foils is a promising energy exchange element for future low energy plasma initiating device. The thermal-electrical performance of small-scale copper bridge foils was simulated using finite element method. Results show that higher temperature acceleration occurs at the corners of the bridge, and then the generated ohmic heat will diffuse all over the bridge. While the energy excitation is identical, the time to melt temperature at the center of the bridge will decrease as the bridge width decreases. Furthermore, when the period of the pulse current remains constant, time to melt temperature will increase as the charge voltage decreases till the bridge cannot reach melt temperature.

Abstract:In order to investigate the effects of binder component on the creep properties of TATB-based polymer bonded explosive (PBX), tensile creep properties, compressive creep properties and three-point bending creep behavior of TATB-based PBX were studied by electronic universal testing machine and dynamic mechanical analyzer, respectively. Results showed that creep resistance performance was improved by the addition of reinforcing agent (styrene copolymer) with high glass transition temperature and high mechanical strength. The creep strain of modified formulation was decreased, creep failure time prolonged. The creep damage time of original formulation obtained by 50 ℃/3 MPa tensile creep, 70 ℃/10 MPa compressive creep and 70 ℃/6 MPa three-point bending creep tests were 14, 12.7, 12 min, respectively. However, modified formulation did not rupture under the same conditions. Based on time-temperature superposition principle, the master curves of TATB-based PBX and its modified formulation were obtained at reference temperature of 60 ℃. Compared with original formulation, the creep compliance master curves of modified formulation shifted downward and the creep resistance performance was enhanced.

Abstract:In order to enhance damage effectiveness of the circumferential Multiple Linear Explosively Formed Penetrator (MLEFP) charge, the influence of the liner curvature radius on the formation of circumferential MLEFP was studied through ANSYS/LS-DYNA. By statistic analysis of the formed assembly Linear Explosively Formed Penetrator (LEFP), the regulation of the liner curvature radius influence to the formation of circumferential MLEFP and the appropriate relatives among parameters were found. Result shows that the circumferential MLEFP warhead can form the linear explosive shaped projectile with a certain speed on four directions to realize circumferential damage and has a certain effect on dealing with armored vehicle and missile under explosive loading. While the ratio of the liner curvature radius and caliber from 0.6 to 0.8, the speed of LEFP formed by the circumferential MLEFP warhead is higher, and the entire kinetic energy is larger, the assembly damage effectiveness is better.

Abstract:In order to study the effects of surrounding humidity on the constant-volume combustion characteristics of winding combustible cartridge case (CCC), the hygroscopic properties of winding CCC were studied by weighing method and the samples saturated in different humidity were tested by a closed-bomb test. The results show that the winding CCC has a better hygroscopic ability.The higher the relative humidity, the stronger the hygroscopic ability. When the relative humidity is 89.0%, the amount of absorption is about 2.89%.Under the condition of loading density of 0.20 g·cm^-3, with increasing the relative humidity, the burning rate of cartridge significantly reduces, and the combustion ending time extends from 2.40 ms to 3.30 ms, the maximum pressure decreases from 189.75 MPa to 174.32 MPa, the impetus decreases from 756.62 kJ·kg^-1 to 649.33 kJ·kg^-1 and the covolume increases from 1.01 L·kg^-1 to 1.30 L·kg^-1.

Abstract:The combustion performance of gun propellants containing FOX-7 at low pressure was studied by quenched burning tests and closed bomb tests. Results show that the pressure exponent reduces with increasing of the content of FOX-7 in propellant, and consecutive melted layer on propellants surface formes during combustion process. It restrains the deflagration of RDX, and the combustion consistency of propellant better, which is helpful for the stable combustion of propellant at low pressure. Impact test results indicate that with the increasing of FOX-7 content in formula, impact strength of propellants improves significantly.

Abstract:Laser-driven miniflyer system is characterized by high precision control in time, prompt initiation, anti EMI and reliable initiation, which meets the requirements of modern initiators. Due to low transmission and utilization efficiency of laser, it′s difficult to apply this system in practice. The velocity of laser-driven flyer in explosive detonation is predicted and the necessity of improving efficiency is put forward. Two key technologies in improving energy efficiency are highlighted and reviewed, including transmission through fibers and coupling with multi-flyer. It must be solved for realizing miniaturized, practical and engineered initiation system of laser-driven flyer to select proper optic fiber, enhance fiber damage resistance, design proper fiber transmission channel, optimize laser parameters, improve structure of multi-flyer, and determine the thickness of each layer.

Abstract:The methods of promoting the ignition and combustion of boron particles were summarized and reviewed, including selection of amorphous boron with appropriate particle size, improvement of the environment temperature and pressure, addition of some substances such as fluoride and water vapor in the atmosphere, coating of boron particles and modification of additives. The mechanisms of various promotion method were explained. The present problems and technical approach needed of solving these problems in promoting the ignition and combustion of boron particles were analyzed and presented with 19 references.

Abstract:The energy release characteristics and damage mode of explosion in confined space were analyzed. The research on the internal explosion effect was reviewed from the 6 aspects of the shock wave characteristics, thermal effect, quasi-static pressure, dynamic response of structural, numerical simulation and explosive synthetic power evaluation. The roof lift facility should be established and strengthen the study on multiple kill element coupling effect on damage of target. The roof lift displacement and quasi-static pressure bring into system of internal weapons power evaluation.

Abstract:

Abstract:By using cyclopent-2-enone as starting material, dimethyl cubane-1, 4-dicarboxylate was synthesized with total yield of 0.7% and purity of 99% via substitution, addition, elimination, Diels-Alder reaction, cycloaddition, Favorskii rearrangement and esterification. The catalyst of esterification was strong acidic cation exchange resin. With the catalyst loading of 2%, it could be used repeatedly three times. The structure of dimethyl cubane-1, 4-dicarboxylate and dicyclopentadienone were characterized by IR, ¹H NMR, ¹³C NMR, MS, and elemental analysis.

Abstract:

Abstract:

Abstract:

Abstract:

Abstract:

Abstract: