Abstract:Products of slow thermal decomposition and fast therlnal explosion of α-Pb(N3)2 were detected by a time-flight mass spectrometer.Different mechanisms of these two reactions vvere determined.In slow thermal decomposition of -Pb(N3)2 ,the first step is excitation of ther π-electron in azide ion to form an azide radical.Then nitrogen gas is formed through bimolecular decomposition of azide radicals,which is the ratecontrolling step in the whole process.In thermal explosion of α-Pb(N3)2 products are nitrogen atom and nitrogen molecule.Formed from simultaneous breakdown fo π-and ó boud in-N3,because of the high energy released in the reaction system.
Yu Tong-chang , Yin Meng-chao , Wang Jian-ling
Abstract:A large adiabatic detonation calorimeter has been designed to determine detonation heat of explosives.The maximuaii tested sample is 50g with shell,which can be detonated in vacuum or in nitrogen atmosphere, The detonation heat (△Hdet) of more than 20 high explosives was determined.The results indicated that for composite explosives,there was a linear accumulative relationship between heat of detonation and its composition,and the former could be calculated from the latter.
Hu Dong , Wang Yong-guo , Lu Hong-bin , Sun zhu-mei
Abstract:The behaviour of deflagration and detonation was studied,for the gaseous mixture of nitromethane and oxygen by means of pressure gaufe and photodetection techniques in an explosion shock tube. It was found that the deflagration (ordetonation) pressure and velocitv increased fluctuantlv with the increase of nitromethane content in the gaseous mixture,The humps formed here from are obviouslv different from the upside down“U”curve of general explosion mixtures. Furthermore,a strong detonation could occur on the end plate of the explosion tube after reflection of the wead deflagration wave in the ignited gaseous mixture.The detonation pressure on the end plate is about 45MPa.CHO,OH radical emission excited by detonation are 10 times greater than that excited by deflagration.
Zhang Tong-lai , Hu Rong-zu , Li Fu-ping
Abstract:Two-point method was established to determine the non-isothermal reaction kinetic parameters of energetic materials by using four parameters from two characteristic points on the non-isothermaI DSC curve. Two peak indexes Hw and τw were defined to judge the non-isothermaI DSC curve of energetic materials.It was found that only when these indexes coincided with the conditions of 0.1≤Hw≤1.0 and 1.8×1O-2≤τm≤9.8× 1O-2,the peak could be treated with kinetics methods. Some empiric judgements were given for chosen the most probable mechanism function and the reasonable kinetics parameters.A typical computation example was listed to compare the two-point method with those commonly used in kinetics.
Jin Shao-hua , Li Wen , Song Quan-cai , Wang Wen-bin
Abstract:The influence of DDT-inhibitor(FPA)on the explosion percentage of polyurethane-bonded-RDX(PU-RDX) under impact,the inhibiting effect on explosion reaction and the quantity of sample residue after reaction were studied.The results demonstrated that the existence of FPA decreases the posslbility of explosion propagation and increases the sample residue after reaction.
Abstract:The route and the optium reaction conditions in two-step synthes of hexanitrostilbene(HNS)are described,where TNT is used as raw material and hexanitrobibenyl(HNBB)is an intermediate.The effect of solvents on the reaction result is discussed as well.
Zhang Zhen-yu , Huan Shi , Lu Fang-yun , Zhu Wen-hui
Abstract:The viscoplastic collapse mechanism of hot-spot formation in pressed porous TNT charges was studied.Amodel was proposed and numerically calculated based on the viscoplastic motion and induced heat of the media around cavities due to the meIting effect.The resuIts showed that in moIten region near the boundary of cavities with different dimensions the temperature was kept near the meIting point, and the existence of the molten region ensured a heat layer with a certain depth under the shock pressure with amplitude of about 3 GPa.Due to the enlargement of molten region during the collapse of cavities,the yield stress tended to zero and viscoplativity was very small in the molten region,these factors may result in a high velocity of cavity boundary collapse,therefore on the close stage of cavity the fluid-dynamics mechanism of ignition must be considered for these samples from large granular,while the melt remarkably decreased the sensitivity of ignition for these samples from fine granular.
Abstract:A review is made with 14 references on the concept of single electron transfer which is progressively accepted in organic chemistry , specially in the radical chain nucleophilic substitution reaction. The concept of single electron transfer is used as an example to elucidate the reaction mechanism of aromatic nitration.
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Editorial Board of Chinese Journal of Energetic Materials
Vol. , No.,
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