Abstract:The expansion of the reaction products of detonating cylindrical charges is presented and analyzed with regard to the radial and axial mean velocities and the real expansion velocities as a function of time and distance.

Abstract:Ａ multiple electromagnetic particle velocity gauge was designed to study the shock initiation processes of HMX and TATB based explosives. The measured particle velocity profiles show the growth from an input shock to a detonation. The results tested by shock trackers indicate that the run distance to detonation of the TATB based explosive under 14.9 GPa impact load is about 5.05 mm.

Abstract:3,6-diamino-1,2,4,5-tetrazine (DATZ) was synthesized from 3,6-bis(3,5-dimethyl-pyrazol-1-yl)-1,2,4,5-tetrazine (BT) with a yield of 95.3%,DATZ was oxidized with peroxyformic acid to give a high-nitrogen energetic compound 3,6-diamino-1,2,4,5-tetrazine-1,4-dioxide (DATZO₂) with a yield of 60.2%. The structures of both DATZ and DATZO₂ are identified and characterized by IR,NMR,DSC,MS,elemental analysis and melting point test etc. Moreover,the effects of reaction conditions on the yield of DATZO₂ were studied, and the optimum reaction conditions are DATZ 1.12 g (0.01 mol),methane acid 200 ml and hydrogen peroxide 4 ml, reaction time 1 h and reaction temperature 25 ℃.

Abstract:Tetraacetyldibenzylhexaazaisowurtzitane (TADBIW) is the cheapest nitrolysis substrate for synthesizing hexanitrohexaazaisowurtzitane (HNIW). The process of crystal transformation of HNIW during nitrolysis is studied. Results show that α-HNIW is obtained from nitrolysis at high temperature, and it can be transformed into γ-HNIW gradually，the crystal transformation can be completed within 3 h at 70-７５　℃ and speeded up by the additon of γ-HNIW crystal seeds in the nitrolysis system.

Abstract:5-Aminotetrazole was synthesized from dicyandiamide and sodium azide in water with zinc bromide as catalyst. The effects of reactant molar ratio, catalyst consumption, temperature and reaction time on the reaction were discussed. The experimental results show that when the molar ratio of sodium azide to dicyandiamide is 1∶1.6 and catalyst consumption of sodium azide to zinc bromide is 1∶0.3, the reaction temperature is 75-85 ℃ and the reaction time is 5.5 h, the yield of 5-aminotetrazole reaches 83.6%. ZnBr_２ is a good catalyst to synthesize 5-aminotetrazole.

Abstract:The RbDNBF (rubidium 7-hydroxy-4, 6-dinitro-5,7-dihydrobenzofuroxanide) is synthesized by reacting sodium salt of DNBF and rubidium nitrate solution. The molecule structure is characterized by IR and the thermal decomposition process is studied by DSC and TG-DTG. The sensitivity properties of RbDNBF are tested by various sensitivity apparatus. The results demonstrate that the bulk density of RbDNBF is higher than that of KDNBF(Potassium 7-hydroxy-4,6-dinitro-5,7-dihydrobenzofuroxanide) and the free-flowing property is also better than that of KDNBF. From 189 ℃ to 236 ℃, the thermal decomposition process occurs with the peak temperature at 210 ℃. The mass percent of solid residue is up to 25%. The sensitivity results show that the sensitivity properties of RbDNBF are equivalent with that of KDNBF.

Abstract:A molecular structure of propyl-nitrate is calculated by using ab initio calculation method. The calculation results indicate that NO₂ radical is fallen away more easily. The delay time of shock ignition is determined by using the method, i.e. intermediate product of the most early emergence for the loaded propyl-nitrate is determined at first with spectrometer, the emergence of intermediate product of NO₂ for propyl-nitrate after shock ignition is always the most early. The monochrometer is adjusted to 463 nm wave length of NO₂, and the time of arriving for shock wave is measured with gauge. The delay time of shock ignition for propyl-nitrate is determined. The delay time determined by the method is closer than that of by using photo-electric diode whose peak wave length is about 800 nm. The measurement results show that the emergence of intermediate product of O for propyl-nitrate after shock ignition is different,and radiation intensity for the radicals is also different. The emergence times for O,NO₂,CO,C₂,CH,CO₂,H₂O radicals is obtained after the shock wave enters into the propyl-nitrate. The emergence time of NO₂ radical is the most early. The method combined the theory with the experiment may obviously decrease tests to determine shock ignition time.

Abstract:TATB based polymer bonded explosive (PBX) was studied by positron annihilation lifetime spectra (PALS) before and after heat treatment. The effect of heat treatment on the microstructure of TATB based PBX was analyzed. The results show that the component of positron annihilation lifetime τ₂ is related to the micropores in PBX. After heat treatment, τ₂ increases while its intensity decreases significantly. Therefore, the dimension of pores in PBX increases while the number of pores decreases after heat treatment.

Abstract:RDX molding powder is prepared by water slurry. The effect of technical process on the coating RDX with polymer solution is studied. The effect of each factor was studied by the sensitivity and particle size. The desensitizing agent and polymer were added as mixture, vacuum pump was used to drive remain solvent in the process and sound result was obtained. Material adding rate,temperature,agitating rate,the secondary addition of ethyl acetate were the main factors affecting the preparation quality and sensitivity of the molding powder. Optimized parameters are obtained: reaction temperature 63 ℃ , agitating rate 300 r·min^-1, adding rate 0.06 mL·s^-1, the weight ratio of ethyl acetate added in the second time and polymer 4∶1. The order of factors affecting preparation quality and sensitivity of molding powder is as follows: secondary addition of ethyl acetate, agitating rate, temperature, material adding rate. Furthermore, secondary addition of ethyl acetate is the most important factor to affect the packing quality and particle size of the product.

Abstract:Ammonium nitrate is modified by adding anti-explosion agent to reduce its impact sensitivity. According to thermal decomposition of AN and hot-spot theory, six chemical materials such as ZnO,(NH2)2CO,Na2HPO4,camphor, Mg2(OH)2CO3,Na2CO3,NH4NO3 were selected as components of anti-explosion agents. Modified AN were prepared by adding these chemical materials to formulate industrial explosives. The impact sensitivity of these explosives at drop height of 65 cm with 10 kg drop hammer was tested. Results show that comparing with the pure explosion in which has no additive, when 5% anti-explosion agent ZnO/Na2HPO4/Mg2(OH)2CO3=33/34/33 are added in system, the impact sensitivity can be decreased from 88% to 24% and the impact sensitivity also declines with the decrease of hardness and stacked density of modified AN. The same result can be obtained by slow crystallization method.

Abstract:When potassium picrate (KP) and KClO₄ are dissolved in water, the solution obtained is bright yellow for the former and colorless for the latter in appearance. With the help of this characteristic, the content of KP in KP-KClO₄ ignition composition is determined by spectrophotometry analysis. The determining conditions is discussed, and the relationship between the absorbance and the concentration of KP is also studied. Results show that the uncertainty and the inaccuracy of the experimental data are 0.2% and 1.3%，respectively, which indicate that the method of determining the content of KP in KP-KClO₄ ignition composition is convenient and feasible for the system.

Abstract:Through modifying proportions of potassium nitrate, sulfur, phenolophthalein and potassium hydrate, formula of charcoal-free black powder is optimized by replacing charcoal with reactant of phenolphthalein and potassium hydrate. Properties between ordinary black powder and charcoal-free powder are compared, including mechanical sensitivity, static eletricity sensitivity, thermal decomposition process and output capacity.The results indicate that the mechanical sensitivity, static electricity sensibility and ignition temperature of charcoal-free black powder is lower than that of ordinary black powder, and the safety ability, working capacity and output stability of charcoal-free black powder is higher than that of ordinary black powder.

Abstract:The relationship between slow cook-off behaviour and thermal decomposition characteristics of NEPE propellant and HTPB propellant was analyzed by simultaneous differential scanning calorimetry and thermogravimetry (DSC-TG), scanning electronic microscope（SEM）and slow cook-off test. A porous state generated in the decomposition of ammonium perchlorate（AP）at low temperature is the main reason causing HTPB propellant reacting violently in the slow cook-off test. The energy released by nitrates at lower temperature enables NEPE propellant to ignite before AP and HMX begin to decompose, which show that NEPE propellant has a milder reaction in slow cook-off test.

Abstract:The effect of lead carbonate (PbCO₃) on the combustion characteristics and thermal decomposition behavior of ammonium dinitramide (ADN) is investigated by burning rate measurement, DSC and TG techniques. Results show that the burning rate of ADN+5% PbCO₃+0.2% paraffin system is higher than that of ADN+0.2% paraffin system in the pressure range of 3-12 MPa, and PbCO₃ enables mesa combustion effect of ADN+0.2% paraffin system to disappear. TG and DSC curves of ADN and ADN+5% PbCO₃ system indicate that the initial decomposition temperature of ADN can be decreased by the addition of PbCO₃. Kinetic analysis for DSC data show that the apparent activation energy of thermal decomposition of ADN decreases when 5% PbCO₃ is added into ADN. Moreover, both combustion characteristics and surface-melting layers of ADN mixtures are considered to be correlative.

Abstract:The effect of oxidizers (HNIW, AP and HMX) and binders (BAMO, GAP, PET and HTPB) on energy characteristics of the AN-based propellants is investigated by the least free energy method. Results show that high energy compound HNIW to increase energy level of the AN-based propellants is always not higher than that of other two oxidizers. The amplitude of HNIW to increase the specific impulse of the AN-based propellants is higher than that of HMX, and less than that of AP when the content of binder is equal to 15%,however the amplitude of HNIW to increase the specific impulse of the AN-based propellants is higher than that of HMX and AP when the content of binder is equal to 5%. Non-energetic binders benefit increasing energy of the AN-based propellants in lower content （＜12%）binder system, but energetic binders benefit increasing energy of the AN-based propellants in higher content（＞13%）binder system. GAP is more beneficial to increasing energy better than BAMO, and every binder all exists a optimum addition amount.

Abstract:The chemical methods of recycling the sulfuric hydrazine with a form of salt from the high concentration wastewater and purifying the low concentration wastewater by Cu^２＋-H_２Ｏ_２ catalytic oxidizing are proposed. The first domestic mobile equipment is developed to purify wastewater containing hydrazine and recover hydrazine. The operational parameters of recovering sulfuric hydrazine is determined, and the important factors such as temperature, concentrated sulfuric acid addition and pH value in reaction are studied. Furthermore, the fundamental principle, the key technique and the operational condition is introduced. The results show that the system works with stable condition and high availability, and the average recovery rate of sulfuric hydrazine reaches 90% over, the treated wastewater is up to the national disposal standard.

Abstract:The study on the formulation and the influence factors to the property of copper-base IR interfering smoke agent as well as measurement results of the property are described. The results show that the smoke agent with excellent interfering capacity on mid-IR and far-IR, has better screening effect on visible lights and laser. Moreover, this smoke agent has some other characteristics i.e. large loading density,better insulation,better performance enduring high and low temperature,better compatible and stable performance.

Abstract:The traditional smoke theory considers that the smoke particles will sedimentate due to gravity after forming of smoke screen, and then the particles reach a final sedimentation velocity thanks to the effect of air-resistance and buoyancy, and the equation can be solved by the Stokes pellet resistance theory and often used to analyze the performance of smoke. In this paper, through outfield experimental research and theory analysis, the Stokes final sedimentation velocity formula is not demonstrated to adapt to analyzing performance of smoke.

Abstract:The suppressive effect of multi-layer wire mesh structure on the combustible gas explosion is studied. Two new important concepts, critical quenching value and critical quenching pressure difference are proposed. Both flame propagation speed and pressure difference are considered to describe the explosion suppression result. Critical quenching value is used to determine the suppression capability of the suppressive structure. The relationship among critical quenching value, critical quenching pressure difference and geometrical parameter of suppressive structure of multi-layer wire mesh is studied. And the empirical formula of the relationship is obtained. With the increase of geometrical parameter（n·M·d）, critical quenching pressure difference and critical quenching value increase, moreover,the quenching capability is improved.

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