Abstract:Using 3,5-dichloropyridazine as starting material, 3,5-diamino-4,6-dinitropyridazine-1-oxide（DADNPO）and a new energetic compound 3,5-diamino-4-nitropyridazine-1-oxide（DANPO）were synthesized by substitution, oxidation, nitration and amination reactions. The structure of products and their intermediates were characterized by IR spectra, ¹H NMR, ¹³C NMR and elemental analysis. The effects of nitrification conditions on the purity and yield of nitrification were studied. The results show that the best nitration reagent of synthesized 3,5-dimethoxy-4,6-dinitropyridazine-1-oxide is nitric acid and sulfuric acid, the reaction temperature is 50~55 ℃, and the reaction time is 15 h. The detonation properties of DADNPO and DANPO were calculated by Gaussian 09 program and Kamlet-Jacobs formula. The results show that the detonation velocities are 8.486 km·s^-1and 7.224 km·s^-1, and the detonation pressures are 30.2 GPa and 23.09 GPa, respectively. Meanwhile, the thermal behaviors of two compounds were studied with differential scanning calorimetry (DSC). The exothermic decomposition peak temperatures of DADNPO and DANPO are 244.4 ℃ and 325.2 ℃ respectively, indicating that DANPO has better thermal stability than DADNPO.

Abstract:6-((2H-tetrazol-5-yl)-amino)-1,2,4,5-tetrazin-3(2H)-one (TATzO) was synthesized and characterized by FT-IR, elemental analysis, ¹H NMR and ¹³C NMR and single crystal X-ray diffraction. The single crystal structure solution indicates that a hydrate forms (TATzO·H₂O) and it crystallizes in the orthorhombic Pnma space group with a density of 1.730 g·cm^-3 at 296 K. The thermal behavior and thermal decomposition kinetic of TATzO·H₂O were studied by differential scanning calorimetry (DSC) and thermogravimetry-derivative thermogravimetry (TG-DTG) methods. The thermal decomposition peak temperature is determined to be 230.46°C, indicating a similar thermal stability to cyclotrimethylenetrinitramine (RDX). The apparent activation energies (E) and pre-exponential constant (A) of the compound are 169.03 kJ·mol^-1 and 15.65 s^-1, respectively. The thermal ignition temperature (T_be) and the critical temperature of thermal explosion (T_bp) is 213.75℃ and 223.03℃，respectively. The enthalpy of formation was theoretically calculated by Gaussian 03, and the detonation velocity (D) and detonation pressure (p) were calculated by the Kamlet-Jacobs (K-J) equation. The obtained D and p are 7757m·s^-1 and 25.74 GPa, respectively. The impact sensitivity is larger than 24 J.

Abstract:A new compound N-(6-hexanol)-2-methoxy-8-nitroazophenyl carbazole(HMNAC) was synthesized by electrophilic substitution reaction and post-azo-coupling reaction,and the structure of HMNAC was characterized by IR,¹H NMR and ¹³C NMR. The molecular structure of HMNAC was optimized at the B3LYP/6-31G(d) level. Single point energy was calculated at the MP2/6-31G(d) level. The relative energy E_R between cis-trans isomers of HMNAC was found to be 52.43 kJ·mol^-1. The third-order nonlinear optical properties of HMNAC were studied by Z-scan technique under nanosecond excitation at 532 nm. Closed-aperture curve has revealed that HMNAC has self-defocusing effect. Open-aperture curve indicated that both saturated absorption and reverse saturated absorption exist in HMNAC. The second-order hyperpolarizability γ of HMNAC was 2.59×10^-29 esu,and the figure of merits(FOMs) reached 1.5.

Abstract:1²,5²-difluoro-1⁴,1⁶,3⁴,3⁶,5⁴,5⁶,7⁴,7⁶-octanitro-2,4,6,8-tetraoxa-1,3,5,7(1,3)-tetrabenzenacyclooctaphane (ZXC-20) was synthesized from 2,3,4-trifluoro-nitrobenzene by nitration, cyclization and nitration. The single crystal of ZXC-20·EtOH was obtained by solvent evaporation method, and its single crystal structure was characterized by X-ray single crystal diffraction. The density of the compound was determined by automatic densitometer. The thermal decomposition temperature of ZXC-20 were recorded on a differential scanning calorimeter (DSC). The detonation parameters such as detonation velocity and detonation pressure of ZXC-20 were calculated by EXPLO5 v6.01. The results show that the crystal belongs to P-1 space group. Its cell parameters are a =10.620(6) Å, b =10.641(6) Å, c=16.549(12) Å, V=1524.5(16) ų, Z=2, F(000)=788.0. The actual density of ZXC-20 is 1.912 g·cm^-3 at 298 K. The thermal decomposition temperature is 333.76 ºC. The crystal belongs to P-1 space group. The theoretical detonation velocity and theoretical detonation pressure of ZXC-20 are 8070 m·s^-1 and 29.5 GPa, respectively, which are better than TATB. ZXC-20 is a potential fluorine-containing heat-resistant explosive.

Abstract:In order to improve the safety performances of ammonium perchlorate-based molecular perovskite ((H₂dabco)[NH₄(ClO₄)₃], DAP), DAP with micro/nano particles were prepared by ball milling. The morphology and structure of the as-obtained samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy (Raman). Thermal decomposition and impact sensitivity was investigated by thermo-gravimetric analysis-differential scanning calorimetry(TG-DSC) and GJB770B-2005 explosion probability method, respectively. The DAP obtained by ball-milling were micro/nano with ellipsoidal particles of 0.5-10 μm, which had relatively smooth surface and good phase stability. The peak temperature of thermal decomposition of micro/nano DAP was 370.6 ℃, which obviously decreased as compared with raw DAP(385.4 ℃). Futhermore, the impact sensitivity of micro/nano DAP(28%) was much lower than that of raw DAP (56%).

Abstract:The three-dimensional nanostructured and degradable polyhemiaminal aerogel (PHA) was used as template to induce the in situ crystallization of 1,1-diamino-2,2-dinitroethylene (FOX-7) by evaporation crystallization method. The FOX-7 with three-dimensional nanostructure (nano-FOX-7) was prepared after the degradation of the PHA in dilute sulfuric acid (10%). The purity of nano-FOX-7 was determined to be 99% by high performance liquid chromatography (HPLC), indicating that the template was almost completely removed. The morphology, phase, structure and thermal properties of the samples were characterized. Detemplated nano-FOX-7 preserved three-dimensional nano structure of PHA. The average size of nano-FOX-7 crystal particle was 83.68 nm. Owing to the special micro-nano structure, the peak temperature of phase transition and first thermal decomposition temperature for nano-FOX-7 was delayed by 11.3 °C and 21.3 °C, respectively. Compared with raw FOX-7, the thermal decomposition of nano-FOX-7 almost completely took at exothermal profile with peak of 291.0 °C. The enthalpy of the thermal decomposition increased from 1309 J·g^-1 (raw FOX-7) to 1421 J·g^-1 (nano-FOX-7), together with 31.6% increase of the apparent activation energy (from 408.80 kJ·mol^-1 to 537.42 kJ·mol^-1), which explained the remarkable improvement of the energy release efficiency and thermal stability for the nanostructure FOX-7.

Abstract:In order to solve the problems of irregular crystal morphology and uneven particle size distribution of 1,1-diamino-2,2-dinitroethylene (FOX-7) obtained by direct synthesis. Solubility, supersolubility and cooling crystallization kinetics of FOX-7 in V(N,N-dimethylformamide)∶V(water)=7∶3 binary system were determined by laser dynamic method and intermittent dynamic method respectively.Results show that the solubility equation of FOX-7 in the above system is . There is a granularity-independent growth model during cooling crystallization.In the nucleation rate and growth rate equation, the supersaturation ratio S index are respectively 0.61 and 0.45, the suspension density M_T index is 2.30, and the stirring strength ω_r index is 0.22.

Abstract:To explore the influence of ordinary hexogen (RDX) and high density spherical RDX on the properties of cast explosives, the crystal morphology, thermal stability and mechanical sensitivity of the two kinds of explosives were evaluated by scanning electron microscopy(SEM), differential scanning calorimeter(DSC) and etc. Taking typical casting formulation as an example, the influence of RDX type on slurry viscosity, density of cylinders, detonation velocity and shockwave sensitivity was discussed. Results show that high density spherical RDX has smooth surface, few crystal defects and high sphericity. The apparent activation energy and enthalpy of activation of high density spherical RDX is 10.79 kJ·mol^-1 and 10.81 kJ·mol^-1 higher than that of ordinary RDX. The impact and friction sensitivity of high density spherical RDX is 20% and 8% lower than that of ordinary RDX. Comparing with ordinary RDX, the high density spherical RDX-based cast formulation shows 41%-45% and 10%-14% decrease in the slurry viscosity and shockwave sensitivity, together with 0.6%-3.9% and 1%-3% increase in the density of cylinders and detonation velocity, respectively showing a better process properties, detonation properties and safety properties.

Abstract:The effects of mass fraction and particle size of 1,1-diamino-2,2-dinitroethylene(FOX-7),different composite combustion catalysts with lead, copper and carbon on the combustion performance of nitrocellulose (NC)/trimethylotethane reinitiate(TMETN） low-insensitive and smokeless composite modified double base(CMDB) propellant with screw extrusion process were investigated by means of strand burner method. The results shown that the burning rate of CMDB propellant is first rise and then descend with the addition of FOX-7. When the FOX-7 content is 25%,the burning rate of CMDB propellant rised from 5.87 mm·s^-1 to 14.90 mm·s^-1 at 10 MPa, and when the content of FOX-7 increases from 25% to 30%, the burning rate decreased from 14.90 mm·s^-1 to 12.78 mm·s^-1 at 10 MPa. The pressure exponent of burning rate between 6-16 MPa decrease from 0.97 to 0.60 as the mass fraction of FOX-7 in the formulation increased from 5 % to 30 %. When the FOX-7 be replaced by finer particles FOX-7 with the same mass, the burning rate decreased 1.16 mm·s^-1 at 10 MPa, while the pressure exponent of burning rate between 6-14 MPa increased. The burning rate of propellant with addition of β-Pb/β-Cu/CB combustion catalyst increases from 14.90 mm·s^-1 to 18.65 mm·s^-1 at 10 MPa, while the pressure exponent of burning rate between 6-16 MPa decrease from 0.63 to 0.35, which compared with the referenced formulation (no combustion catalyst).

Abstract:To improve the mechanical property of single-based propellant with high nitrogen content, nitrocellulose/2,4-dinitrotoluen/diphenylamine(NC/DNT/DPA), 3% dimethylsulfoxide(DMSO), N,N-dimethylformamide(DMF), cyclohexanone, cyclohexane, chloromethane, ethyl acetateandbutyl acetate were added to alcohol ketone respectively to form ternary mixed solvent, plasticizing high-nitrogen nitrocellulose and obtaining the corresponding single-based propellant. The microstructure of single-based propellant samples were observed by scanning electron microscopy, and the mechanical properties were tested by universal material testing machine and beam impact testing machine. In addition,the energy of single-based propellant samples were studied by closed bomb test. Results show that when the auxiliary solvents are added, the mechanical properties of the high-nitrogen single-based propellant samples are improved. The compressive strength of the sample with 3% butyl acetate at low temperature (-40 ℃), normal temperature (20 ℃) and high temperature (50 ℃) increases by 15.7%, 4.3% and 17.7%, and the impact strength increases by 26.9%, 96.9% and 170.0%, respectively. The addition of the auxiliary solvent has little effect on the combustion of single-based propellant. And compared with the basic single-based propellant, the gunpowder force of the single-based propellant samples prepared by the ternary mixed solvent has a small decrease.

Abstract:In order to improve the performance of burning progressivity and low temperature sensitive coefficient effect of high-energy azidonitramine gun propellant, three insensitive high-energy azidonitramine gun propellants was prepared by the two-stepprocess with polymer composite materials plugging and energetic composite materials desensitization” (called plugged and insensitive gun propellant in this study), whose inner hole was blocked by polymer composite materials and surface was desensitized. The energetic and static combustion performance of plugged and insensitive gun propellant was investigated by heat of explosion and closed-bomb tests. Results show that compared with the untreated gun propellant, with the increase of the content of plugged and insensitive materials, the heat of explosion of three types of plugged and insensitive gun propellants (WCBF-1/18, WCBF-2/18, WCBF-3/18) decrease by 2.6%, 3.6%, 4.3%, and P_r values increase from 0.471 to 0.552, 0.563, 0.576 respectively. The average absolute values of temperature coefficient of relative combustion activity at high temperature for three types of plugged and insensitive gun propellants WCBF-1/18, WCBF-2/18, WCBF-3/18 are 2.87%, 1.89%, 1.56%, respectively, which are all lower than that of untreated gun propellant, it shows that the low temperature sensitivity coefficient effect in the high and normal temperature ranges for plugged and insensitive gun propellant can be improved.

Abstract:To study the physical mechanism of the premature-combustion phenomenon in the FAE explosion process, propylene oxide was used as the FAE explosion fuel. Based on the theory of fluid mechanics, numerical simulation software ANSYS was used to simulate the fuel dispersion process of a 2 kg FAE device. The results show that the central charge has a significant impact on the premature-combustion behaviour. After the detonation of central charge, high temperature and high pressure are generated to promote the fuel dispersion. Due to the mechanism of heat conduction and thermal radiation, the temperature field and the pressure field also exist in the FAE cloud field formed by the fuel dispersion. Premature-combustion occurs when the temperature and concentration density of the FAE cloud field meet critical conditions. Numerical simulation indicates that the location of the premature-combustion approxiamtely locates near the top of the FAE device, and the premature-combustion time is concentrated within 1~5 ms after the fuel begins to disperse.

Abstract:In order to explore the process of aerosol cloud formation caused by explosive dispersive stimulant in divided structure, firstly, a test sample grenade with divided charge structure was designed .Secondly,the principle sample bomb was divided into two types: ground explosion and air explosion under static conditions.The formation and movement of aerosol cloud during the process of explosive dispersive o-chlorobenzylidene malononitrile(CS) irritant agent were studied by using high-speed photography technology,and the variation rules of diameter,,radial velocity and diffusion height of aerosol cloud group with time were obtained,the results of ground explosion and air explosion dispersion tests being different. Finally,through the theoretical analysis of irritant aerosol cloud movement process driven by explosion, the mathematical model of velocity is established which agrees with the experimental results.Results showed that in both ground and air explosions ,the general rules of the explosive dispersive CS irritant agent process of the divided structure are basically consistent,which can be divided into radial acceleration stage,deceleration stage,turbulence stage and diffusion stage. The cloud parameters at the end of the first two stages can provide the initial conditions for predicting the effective area of explosive tear gas and estimating the power range.The maximum velocity of ground explosion is 1495 m·s^-1 at 0.7 ms, and that of air explosion is 1697 m·s^-1 at 0.3 ms.Compared to an air explosion, for an ground explosion, the shockwave produces reflection superposition on the cement ground, which is conductive to the diffusion of the radial movement of the flow field and particles, and the ground explosive dispersive cloud group has a larger diameter,while the axial diffusion height is small.

Abstract:Different types of equipments are installed in the warship cabins according to their functions. However, present research of cabin internal blast damage mainly focuses on the effects of damage elements on vacant cabin, and the effects of the equipments installed in the cabin are seldomly considered. By using the finite element software LS-DYNA, three types of rib-reinforced cabin models, including the one installed with no equipment, the one with one equipment, and the one with two equipments, were built. The analysis of the damage of cabin structure and equipments caused by the internal blast of warhead charge and the comparative analysis of the influence of equipments on the damage effect were conducted. The comparative analysis results show that, because of the obstruction of the equipments, different arrangements of equipments affect the internal flow field distribution of shock waves in a cabin and convergence of shock waves in corners, reduce the maximum overpressure value and change its location, which finally lead to the change of the cabin structure′s damage process .

Abstract:In order to explore the interaction between the optimal technologic conditions and influencing factors of high gravity-enhanced heterogeneous catalytic ozonation for phenol mineralization, response surface methodology (RSM) was used to optimize the experiment. According to the principle of Box-Behnken Design （BBD） center combination design, four-factor and three-level experiments were designed. The effect of high gravity factor (β), initial pH, liquid flow rate (Q_L), ozone concentration (C_O3) on the mineralized phenol wastewater was investigated. The mathematical model of the technology was established and the optimized technologic parameters were determined. Results show that there is an extremely significant interaction between β and initial pH, and a significant interaction between β and Q_L. The optimal technologic parameters are as follows: β is 60, initial pH 5.47, C_O3 62.5 mg·L^-1, and Q_L 89.95 L·h^-1. The predicted value is 91.54%, 0.97% (<2%) higher than the measured value. It can be concluded that the obtained secondary mathematical model for the phenol mineralization via high gravity-enhanced heterogeneous catalytic ozonation has a good reliability for the optimization of technologic conditions and prediction of mineralization rate of phenol wastewater. In addition, the coupling between high gravity technology and heterogeneous catalytic ozonation technology is beneficial to the formation of OH radical, which reacts with organics, from the rapid decomposition of ozone in liquid phase. Thus, the phenol mineralization via high gravity-enhanced heterogeneous catalytic ozonation follows OH mechanism, and the phenol wastewater could be completely mineralized within 30 min.

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