Abstract:Based on the experimental perforation of projectile impacting stiffened plate, numerical simulations were conducted to study the failure pattern of target, projectile trajectory and the anti-perforation capability of target. The results show that stiffeners enhance the strength and rigidity of target, and change the whole structure capability and the failure pattern of target. For the single stiffened plate, single stiffened plate with "T" sectioned stiffener and cross stiffened plate, the increase of limit penetration velocity for different stiffeners and projectiles is 35%~80%. The maximum deflexion angle of projectile is 35°~40°.

Abstract:Damage enhanced materials were used to improve damage efficiency of fragments antiaircraft weapons. A kind of damage enhanced fragments (DEF) containing Al/PTFE with dimension of Φ10 mm×10 mm was designed and prepared. Damage performance experiments show that damage enhance fragments attack targets not only by kinetic energy,but also by combined damages such as exploding,overpressure, high temperature,and setting fire etc. The results show that the designed damage enhance fragments have remarkably higher damage performances than steel fragments with the same dimensions,and its potential chemical energy is 12.4 times as high as its kinetic energy.

Abstract:In order to study the boundary pressure of charge hole in warhead and the effects of the relative hole bulk on the temperature in hole, a model of charge hole was established by ANSYS software, and transformation characteristic of the hole was simulated with solid-liquid coupling method of LS-DYNA. The transformation process of hole under loading was studied as well. Results show that, with loading rates increasing, the relative bulk of hole lessens and the boundary pressure of the hole increases. However, when the load is up to the maximal load and maintained, their change is slow.

Abstract:3,5-Dinitropyrazole ammonium salt was synthesized with 3-nitropyrazole asprimary substance by nitration and rearrangement. Their structures were confirmed by IR, NMR, MS and elemental analysis. Reaction condition was optimized by HPLC and TLC. The optimization reaction temperature was 147 ℃, reaction time was 77 h and the conversion was 96.5%. Dinitropyrazole ammonium salt was directly gained by ammonia gas neutralization.

Abstract:3-Amino-4-nitrofurazan(ANF) was successfully synthesized from 3,4-diamino-furazan(DAF) by an improved method. In the synthesis,oxalic acid was employed with sodium tungstate as a cocatalyst instead of sulfuric acid,and 30% H₂O₂ was employed as the oxider instead of 50% H₂O₂. The effects of reaction temperature,reaction time and quantity of catalyst on the conversion of DAF to ANF was studied by orthogonal design. The optimal reaction conditions were obtained as follows: reaction temperature 30 ℃,reaction time 6 h,the mole ratio of cocatalyst to DAF 1：1. The conversion of DAF was about 33.70% under the optimal reaction conditions.

Abstract:The ordinary RDX was recrystallized in dimethyl sulfoxide (DMSO) solvent with Twin-80 crystal modifier to improve its morphology and reduce its sensitivity. Optical microscopy and density-bottle were utilized to analyze RDX sample before and after recrystallization,the results show that apparent density of recrystallized RDX is increased by 0.007 g·cm^-3 and the recrystallized RDX has more regular and smooth crystal morphology. The recrystallized RDX and ordinary RDX were used respectively in the same cast PBX formula. The shock sensitivity of the two formula was compared by small scale gap test (SSGT) equipment,the results show that recrystallized RDX formula has 25% lower shock sensitivity than ordinary RDX formula.

Abstract:In order to improve the purity of RDX in nano-structured explosive by eliminating bacterial cellulose(BC),enzymatic hydrolysis was adopted. The effects of explosive on enzymatic hydrolysis of BC,such as enzyme concentration,hydrolysis time and temperature were investigated. The results show that RDX inhibits enzymatic hydrolysis of BC and hydrolysis degree of BC(HDBC) varies with enzyme concentration,hydrolysis temperature and time; HDBC increases with the increase of enzyme concentration and hydrolysis time at 45 ℃,50 ℃ and 55 ℃; the best temperature of enzymatic hydrolysis for BC is around 50 ℃.

Abstract:To improve the stability and consistency of base bleed unit while the projectile was out of the gun muzzle, the characteristics of transient combustion of composite base bleed charge was studied by using a semi-closed bomb to simulate a abrupt depressurization and a high speed digital video camera to record the phenomena of combustion. The pressure of combustion chamber in semi-closed bomb was controlled to vary from 20 MPa to 90 MPa, and the velocity of depressurization from 1.2×10³ MPa·s^-1 to 6×10³ MPa·s^-1. The results show that there are three kinds of combustion characteristics, e.g. reignition,extinguishment and critical case, when pressure and depressurization rate change. The depressurization rate and the pressure before depressurization are key factors influencing the combustion of base bleed charge. The analysis indicates that the cornbustion of base bleed charge is in the critical zone between extinguishment and reignition when the base bleed projectile is just out of the gun muzzle.

Abstract:The object of the research are explosive properties of the pyrotechnic composite consist of fine grade magnesium-aluminium powder (PAM) and highly dispersed polytetrafluorethylene (PTFE). The composite reveals high resistance to all mechanical and thermal impulses and is extremely sensitive to hot sparks and open fire. The burning rate of the composition changes from 1 cm·s^-1 to 100 m·s^-1 along with decreasing its density. Charges of the composition with density below 1 g·cm^-3 burn so violently, that the phenomena is similar to explosion. Charges with density above 1.1 g·cm^-3 burn relatively rapidly and stably. The main part of the paper concerns the pressure impulses in the air generated during high-rate burning of the composition of bulk density. The nature of the generated pressure impulse is not that of a typical shock wave. A rise of pressure over the distance from the point of explosion to the maximum value lasts 50-100 milliseconds, while for shock waves this factor is less than a microsecond for equivalent charges. The methods of initiation of the composition influence the shape and parameters of the pressure impulse. The explanation of the nature of great changes of the composition burning rate has been proposed. The effect described in the paper was used for evaluation of explosive pressure resistance of industrial doors and windows.

Abstract:A energy-increased desensitized propellant was obtained by dipping of nitroglycerine and addition of fire-retardant polyester materials into 11/7 single-base propellant. The tests were carried out in an ignition apparatus and a closed bomb. The results of ignition test show that ignition delay time of the energy-increased propellant decreases from 5.8 ms to 4.1 ms, while that of the energy-increased desensitized propellant increases from 5.8 ms to 45.5 ms. The results of the closed bomb show that combustion time of the original single-base propellant is 9.5 ms,the energy-increased propellant is 8.5 ms,and the energy-increased desensitized propellant is 10.86 ms,respectively. The energy-increased desensitized propellant has very progressive combustion properties.

Abstract:New green primary explosive bis-furoxano-nitrophenol potassium salt (KBFNP) were synthesized from bis-uroxano-nitroanisole (BFNA) and potassium carbonate. Its purity, morphology and structure were analyzed by high performance liquid chromatography, digital microscope, FT-IR spectra, and elemental analysis. The heat property and explosive property were also studied. The results show that KBFNP has a potential application in replacement of lead styphnate and mini-impulse system because of its good ignition and gas-making capability.

Abstract:To describe the randomicity and uncertainty of engineering tests′ result, Test Information Entropy was presented. The similarities and differences between Test Information Entropy and usual information entropy were discussed on the aspects of purpose, requirement, basic model and mathematical tool, etc. Furthermore, the Test Information Entropy of high reliability product with zero-failure was given. Two application examples of Test Information Entropy show that it is feasible for application of Test Information Entropy.

Abstract:To assess the high reliability of initiating explosive device with small samples, the test design plan with small samples for initiating explosive devices was studied. Based on test information entropy, a new test design method was put forward. With this method, reliability of No.54 stab detonator which is used in head kindling organ of H/DR131 fuze was assessed. Twenty-two products were tested on the stress level of 4.5 cm and all fire. The assessment result is in agreement with the test result with 1800 samples. The product meets the reliability requirements with reliability of 0.999 at the confidence level of 0.90.

Abstract:In order to improve the extinction performance of red phosphorus smoke to 10.6 μm laser emission,the extinction coefficients of nanometer alumina aerosols, red phosphorus smoke and their combined smoke to 10.6 μm laser emission were tested in a middle smoke chamber. Results show that, under the air relative humidity of 40%,the extinction coefficients of nanometer alumina aerosols, red phosphorus smoke and their combined smoke to 10.6 μm laser emission with incident power of 1W are 0.222 m²·g^－１,0.298 m²·g^－１ and 0.449 m²·g^－１, respectively. It indicates that nanometer alumina combined with red phosphorus smoke improves the diffusion performance of nanometer alumina remarkably, and the extinction coefficient of the combined smoke enhances by 50.7% than that of red phosphorus.

Abstract:The availability and accuracy of molecular force fields limit their application scope. In this work, a first principle and all-atom force field for 1,3,3-trinitroazetidine (TNAZ) was developed based on the TEAM method. The valence parameters and atomic partial charges were derived by fitting to ab initio data. The van der Waals (VDW) parameters were taken from the literature and optimized using experimental densities and vaporization enthalpies of liquids. In order to validate the force field, the properties of TNAZ in gas, solid and liquid states were calculated. It has been shown that the force field is highly accurate in predicting the above properties, which include molecular structures, vibration frequencies, liquid densities, vaporization enthalpies, crystal structures, and lattice energies. The isobaric and isotherm curves of the condensed phases were calculated. The isobaric curves can be partitioned into three regions. The volume of crystalline TNAZ at 300 K is about 13% smaller than that at 400 K, which is consistent with the experimental observation. The volume of crystalline TNAZ is reduced by about 28% when the system is compressed under 10 GPa pressure and 300 K, which is consistent with other theoretical predictions.

Abstract:In this paper molecular dynamics (MD) simulation was applied to validate COMPASS force field for HMX. The crystal parameters of β-HMX crystal under atmospheric pressure and at seven different temperatures from 205 to 385 K were then calculated with MD simulation using NPT ensemble for β-HMX (4×2×3) primary simulation cell. Both linear coefficients of thermal expansion (CTEs) in the crystal a,b and c directions and volume CTEs were obtained using linear correlation method. These theoretical calculation results are in agreement with the previous experimental and theoretical data.

Abstract:The eight kinds of descriptors were calculated by Gaussian98 and Cerius2 program packages on the basis of structure-properties, such as electron and space of substance. The descriptors include the dipole, the energy of the highest occupied molecular orbital(E_HOMO）, the energy of the lowest virtual molecular orbital（E_LUMO）, molecular total energy(E), rotable bonds, the bond length of the weakest R—NO₂, Hbond donor and midpoint potential(V_mid). The relationships between the densities of aromatic explosives and the eight kinds of descriptors were established by QSPR method in Cerius2 program package, and the correlative coefficient was 0.909. The average errors between the prediced and experimental densities were 3.33 and 2.94 percent in the training set constituted by 30 compounds and the predicting set constituted by 15 compounds separately.

Abstract:The non-isothermal crystallization of 3,4-dinitrofurazanofuroxan (DNTF) in octalzydro-1,3,5,7-tetranitro-1,3,5,7-trtrazocine (HMX) was researched by differential scanning calorimetry. Several kinetics models were used to investigate the crystallization behavior of DNTF and the obtained results were compared. The results show that HMX can reduce the super-cooling degree of DNTF and eliminate self-heating of DNTF crystallization. The crystallization kinetics exponent n was obtained from Avrami equation and the mechanism function g(α) was determined. The active energy of non-isothermal crystallization kinetics parameter of DNTF were obtained from Kissinger equation. Furthermore, Ozawa exponent m and temperature function F(T) were obtained from Avrami-Ozawa equation. The results also show that the non-isothermal crystallization process of DNTF can be preferably described by Avrami-Ozawa equation.

Abstract:Supposing the Frank-Kamenetskii parameter δ as stochastic variable of normal distribution, the thermal sensitivity probability density function of energetic materials was worked out, by the application of the probability density formula of monotone function, and the thermal safety degree of energetic materials was calculated. The results show that: the thermal sensitivity of energetic materials is not a normal distribution, but a kind of new probability density function decided by geometric factors (the characteristic measurement of reactant and geometric shape of reactant) and chemical factors (quantity of reaction heat, activation energy, density, frequency factor, and thermal conductivity), the value of safety degree is decided by the sensitivity distribution function.

Abstract:The model predicting the detonation velocity of explosives was founded on the back propagation (BP) neural-network (BP neural-network has been trained by a hybrid genetic algorithm which based on elitist model algorithm and adaptive crossover mutation), the three-dimension data modeling, molecular weight, oxygen balance and charge density of explosives. The detonation velocity of some explosives were predicted by using the ameliorative BP neural network model. The forecast results indicate that the predicted values by using this model approaches the experimental volues in literature. The absolute errors are ±7%. And there are some analogies between the relative parameters (including the molecular, oxygen balance and charge density of explosives) and the detonation velocity of explosives. The results also show that the yield model has high predicting accuracy. It is a novel method for predicting and estimating the detonation velocity of new explosives.

Abstract:Geometrical structures of furoxan monomer and dimers were optimized at the B3LYP/6-31++G^** level. It is found that the planar structure of sub molecule is not changed in the process of forming a dimer. Based on the frequency vibration results,it can be speculated that the π-π conjugation in the structure has influence on the C—H stretching. Consequently,the C—H stretching exhibits some red shifts and its intensity is strengthened. The ²ρ at bond critical points(BCP) of C—H bonds are negative,contrary to those of O…H and N…H hydrogen bonds. It indicates that the O…H and N…H hydrogen bonds (HB) are accord with the common HB features. The capability of the dimers to concentrate electrons at BCP of C—H bonds enhanced. The recently developed aymptotically corrected symmetry-adapted perturbation theory,combined with density functional theory,was used to study the contributions of intermolecular interaction energy of furoxan as a simple model. The electrostatic energies of dimer Ⅰ and dimer Ⅱ are -30.10 kJ·mol^－１ and -37.36 kJ·mol^－１ respectively,which are equal to the total energies. It directly reflects that the HB interaction of furoxan is dominated by electrostatic energy.

Abstract:The surface physicochemical properties of hydroxyl terminated polybutadiene (HTPB) were studied by means of inverse gas chromatography（IGC）. The dispersive component of the surface free energy of HTPB, as well as the total surface free energy decreases as the temperature increases. Compared with the polyethylene， HTPB has higher surface free energy because there are some hydroxyl groups on the surface of the HTPB molecule. While the proton donor and the proton acceptor components increase with the increase of the temperature, the proton donor one is more sensitive to the temperature and increases more rapidly. The results show that HTPB has higher dispersive component and shows stronger Brnsted acidity.

Abstract:To prove the validity of molecular simulation technique,Synthia and Blends modules in Accelrys Materials Studio were used to simulate steric hindrance parameter, Young′s modulus,zero-shear viscosity and activation energy for viscous flow,surface energy, and Flory-Huggins interaction parameter of the nitrate esters for polyester,polyether and polybutadiene type polyurethane binder. The simulation data are consistent with the reported experimental results and can supply references for designing new propellant binder.

Abstract:Solubility of hexanitrohexaazaisowurzitane （HNIW） and its changes with temperature in three kinds of different concentrations of nitric acid were measured.The process of crystal transition from α, γ-HNIW to ε-HNIW in nitrate acid was studied. ε-HNIW with different crystal quality were obtained by changing concentration of HNO₃, temperature of adding crystal seeds, stirring rate. ε-HNIW is obtained in 90% nitric acid when the temperature of adding crystal seeds is in the range of 34-40 ℃ . Its yield and purity is over 98%，99% respectively, and acid number is below 2‰ (as HNO₃).

Abstract:Thermal decomposition of two kinds of hexanitrohexaazaisowurtzitane（HNIW）particles (230 μm,40 μm) were studied by TG-MS. The isothermal decomposition residues of HNIW with larger particle (230 μm) were researched by FTIR spectra and elemental analysis. The results in the non-isothermal decomposition show that there are two steps for HNIW with larger particle and only one step for HNIW with small particle, the main products are NO,N₂O,CO₂, a small amount of NO₂ and C₂N₂H₂. Isothermal decomposition products of HNIW with large particle at 204 ℃ are same as in the first step of the non-isothermal decomposition. The average molecular formulas of the residues at 204 ℃ for 10 minutes and 60 minutes are C₃H_4.5N_5.5O,C₂H₄N₂O. The total of isothermal decomposition reaction at 204 ℃ is C₆H₆N₁₂O₁₂=6NO+N₂O+2CO₂+2HCN+C₂H₄N₂O.

Abstract:A simple formula of estimating the standard hydrous enthalpy of cation and anion,Δ_hH^θ_m(M^n±) was presented. The errors between calculated and reported values of Δ_hH^θ_m(M^n±) was within 8%. The standard enthalpies of formation of cations and anions with known Δ_hH^θ_m(M^n±) and Δ_fH^θ_m(M^n±,aq,∞) or Δ_fH^θ_m(M^n±,g), Δ_fH^θ_m(M^n±,g) or Δ_fH^θ_m(M^n±,aq,∞) were estimated by the formula established.

Abstract:In order to study the relationship between the structures and sensitivities of energetic coordination compounds,the enthalpies of solution of ［Mn(CHZ)₃］(NO₃)₂ and ［Mn(CHZ)₃］(ClO₄)₂ in deionized water were measured by a Setaram C80Ⅱ microcalorimeter at 298.15 K. The standard molar enthalpies of solution were obtained to be 91.13 kJ·mol^-1 for ［Mn(CHZ)₃］(NO₃)₂ and 87.09 kJ·mol^-1 for ［Mn(CHZ)3］(ClO4)2. Their lattice energy were calculated farther as ［Mn(CHZ)₃］(NO₃)₂ being 1737.36 kJ·mol^-1 and ［Mn(CHZ)₃］(ClO₄)₂ being 1485.36 kJ·mol^-1 through Kapustinskii formula,and the thermochemistry radius of ［Mn(CHZ)₃］ ²⁺ was obtained to be 2.12Å. The relationship between lattice energy and impact sensitivity or friction sensitivity was discussed. The more the lattice energy is,the lower the sensitivity is. ［Mn(CHZ)₃］(NO₃)₂ is more insensitive than ［Mn(CHZ)₃］(ClO₄)₂.

Abstract:The integrated Fenton and Fenton-like processes to improve the degradation efficiency were reviewed. Ultrasound and microwave assisted advanced oxidation processes for decontamination of organic wastewater were described. The transition metal ions in the wastewater or oxides in the clay, zero valent iron, fly ash, etc, could be used as the alternative catalysts for Fe²⁺ and generate hydroxyl radical to degrade the energetic compounds. The competitive purification process in cost for energetic material wastewater could be developed by integrated processes and enhanced Fenton processes.

Abstract:Some key techniques of measuring propellants and explosives by temperature-dependent FTIR were summarized. And the sample preparation techniques for different objects and goals, spectra analysis of phase transition and reaction process, and data processing on kinetic study were also discussed.

Abstract:

Abstract:

Abstract:

Abstract: