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Abstract:For the ignition reliability of the semiconductor bridge miniaturization, the electrical explosive process of composite semiconductor bridge (SCB) with different charging voltages under 22 μF were studied by high-speed digital oscilloscope. The electrical explosive performance of composite SCB was compared with that of polycrystalline silicon SCB. Results show that before erupting, the electrical explosive process of composite SCB is in accordance with that of polycrystalline silicon SCB basically, and after erupting, especially at the high voltage, the current of composite SCB decreases, and is lower than that of polycrystalline silicon SCB. The time of the erupting of composite SCB is longer than that slightly. The energy acted on the plasma of composite SCB is a little larger than that of polycrystalline silicon SCB, and the energy acted on the plasma of compound SCB increases more than that of polycrystalline silicon SCB in 3 μs after erupting, so the ignition reliability of composite SCB is better than that of compsite SCB. The primary cause, which results in the differences above, is the metallic film on composite SCB.

Abstract:7-Azidofurazano[3, 4-b]tetrazolo[1, 2-d]pyrazine(AzFTP) and 7-aminofurazano[3, 4-b]tetrazolo[1, 2-d]pyrazine (AmFTP) were synthesized using 5, 6-dichlorofurazano[3, 4-b]pyrazine as starting material, via azidation and amination reaction. The single crystal of AmFTP was firstly cultivated and tested by single-crystal X-ray diffraction. The crystal belongs to orthorhombic system, space group P2₁2₁2₁ with crystal parameters a=0.7117(18) nm, b=0.8088(2) nm, c=1.1871(8) nm, V=0.6833(3) nm³, Z=4, D_c=1.732 g·cm^-3, μ=0.138 mm^-1, F(000)=360, R₁=0.0376, wR₂=0.0988. Thermal properties of target compounds were studied using differential scanning calorimetry(DSC) and thermogravimetric(TG). Results show that AmFTP has better thermal stability than AzFTP.

Abstract:3, 4-Bis(3-nitrofurazan-4-oxy)furazan (1) was synthesized from 3, 4-diaminofurazan by Caro′s acid oxidation, hydrolysis, neutralization and substituent reactions, and its structure was characterized by IR, NMR, elemental analysis, and X-ray single-crystal diffraction analysis. The crystal belongs to the monoclinic system, space group P2₁/c with a=15.256(3)Å, b=11.579(3)Å, c=14.981(3)Å, β=117.624(4)°, M_r=328.14, V=2344.7(9)ų, Z=8, D_c=1.859 g·cm^-3, F(000)=1312, μ=0.177 mm^-1, S=1.012, the final R=0.0433 and wR=0.0987. X-ray single-crystal diffraction analysis indicate that compound 1 crystallizes in two crystallographic independent host molecules with different conformation and several intermolecular interactions among oxygen atoms and nitrogen atoms lead to a high density. The thermal behavior of compound 1 was studied by TG-DTG and DSC techniques. Results show that it melts at 72.9 ℃ and is highly exothermic from 245 ℃ to 346 ℃.

Abstract:Molecularly imprinted polymer (MIP) microspheres were prepared via precipitation polymerization with hexanitrohexaazaisowurtzitane(CL-20) as template, acrylamide as functional monomer, trimethylolpropane triacrylate as crosslinking agent, acetonitrile as solvent and porogen and 2, 2-azobisisobutyronitrile (AIBN) as initiatives using molecularly imprinted technology (MIT). The optimum synthetic conditions were obtained as follow: the molar ratio of the template, functional monomer and crosslinking agent was 1:7:20 and the experiment temperature was 60 ℃. The synthesized polymer microspheres are regularly spheres and their diameter is about 1 μm. The interaction between the CL-20 and the function monomer was determined by UV-visible adsorption spectrum, and the microstructures of CL-20/MIP and NMIP were observed by scanning electron microscope (SEM). Results show that the CL-20 interacts with the functional monomers, and CL-20/MIP microspheres have good sphericity and are independent to each other, while a certain degree of reunion phenomenon is found in the NMIP microspheres. The recognition capability studied by equilibrium binding experiment show that the equilibrium binding capacity of the microspheres is 14.02 mg·g^-1 in CL-20/alcohol solution with the concentration of 0.4 mmol·L^-1, while the binding capacity of NMIP is 6.77 mg·g^-1. The amounts of RDX and TNT adsorbed by CL-20-MIP in selective binding experiments is 6.98 mg·g^-1 and 8.46 mg·g^-1, respectively, indicating MIP possesse recognition property of CL-20. The adsorption thermodynamics shows that CL-20-MIP and NMIP have good adsorption property and are accord with Freundlich adsorption isotherm. Studies of adsorption kinetics show that the adsorption of CL-20-MIP can simulate by pseudo-first order and pseudo-second order kinetics models, but the latter equation is better.

Abstract:The technology for synthesizing 2, 6-diamino-3, 5-dinitropyrazine-l-oxide (LLM-105) was studied by oxidation of 2, 6-diamino-3, 5-dinitropyrazine(ANPZ) on kilogram scale. The yield of LLM-105 is 98.3% and its purity 96.4%. The dosage of trifluoroacetic acid (TFA) is reduced. The structure of LLM-105 was characterized by IR, elemental analysis, ¹H NMR and MS. The recovery technology of TFA mother solution was studied by neutralization, acidification and distillation on kilogram scale. The recovery of TFA is 85.1% and its purity 99.8%. Using the recovery TFA for the oxidation reaction of ANPZ, the yield of LLM-105 can be 97.8%. The factors affecting the oxidation reaction were discussed. The optimum technology parameters of the oxidation reaction are: m(ANPZ):V(H₂O₂)=1:1.8, m(ANPZ): V (TFA) =1:5, reaction temperature 25~30 ℃, reaction time 14 h.The optimum technology parameter of recycling of TFA is m(TFA):V(H₂SO₄)=1:1.0.

Abstract:Pentacyclo[5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane(PCU) is a compound with potential application in high energy density caged hydrocarbon compounds. PCU as a high-energy additive can enhance the energy level of the liquid hydrocarbon fuel. The results show PCU has a combustion heat 44.5 MJ·kg^-1 and is insensitive to impact and friction. The physico-chemical properties of blending fuel which is composed of aviation kerosene RP-3 and PCU were studied. Results show that the saturated solution of mass fraction of PCU in kerosene RP-3 at 25 ℃ reaches 44.6%. When mass fraction of PCU in the blending fuel reaches 25%, in comparison with pure aviation kerosene RP-3, the density and volumetric heat content of the blending fuel increase by 7.8% and 9.5%, respectively, the flash point of the blending fuel increases from 48 ℃ to 49 ℃, and the freezing point of the blending fuel decreases from -59 ℃ to -62 ℃. The viscosity of the blending fuel at -40 ℃ is between 6.99 mm²·s^-1 and 13.64 mm²·s^-1. The blending fuel with 10% PCU can perform smooth ignition and stable combustion on a scram jet direct-connect test facility. PCU makes the supersonic combustion pressure of aviation kerosene RP-3 increase from 327 kPa to 339 kPa.

Abstract:The energy characteristics of high energy solid propellants based on the block copolymer (BAMO/AMMO) of 3, 3′-bis (azidomethyl) oxetane (BAMO) and 3-azidomethyl-3-methyloxetane(AMMO) (BAMO/AMMO) as binder were calculated by "Energy Calculation Star (ECS)" code. The influence of different plasticizers (diazidopentane (DIANP), glucidyl azide polymer (GAP) and butyl nitrooxy ethyl nitramine (BuNENA)), oxidants (ammonium perchlorate(AP), hexanitroxaazasowurtzitane(CL-20), furazan compounds(3, 4-dinitrofurazanfuroxan(DNTF), dinitroazodifuroxan(DNAF) and diazidoazofuroxan(DAAOF)), and high energy fuels (aluminium (Al) powder and aluminum trihydride (AlH₃)) on the energy characteristic parameters(specific impulse(I _sp), combustion temperature (T_c) and oxygen coefficient (φ), etc.) of BAMO/AMMO based propellants were studied. Results show that I _sp of propellant plasticized with Bu-NENA is greater than that of BAMO/AMMO based propellants plasticized by DIANP or GAP. With replacing AP by CL-20 gradually in propellant plasticized by Bu-NENA, the T_c of BAMO/AMMO/BuNENA based propellant shows a trend of increase early and decrease then. When the content of CL-20 is more than 55%, the I _sp of propellant remains the same and increases to maximum. When AP was replaced by CL-20 entirely, the value of I _sp is declined. The substitution of DNAF for CL-20 makes the I _sp of propellant enhance from 2723.71 N·s·kg^-1 to 2798.00 N·s·kg^-1. When Al powder and CL-20 are replaced by AlH₃ and the value of φ of system is increased, the energy of propellant is sharply increased.

Abstract:The effects of energetic imidazoles lead salt (E-Pb) content and E-Pb-carbon black composite on the combustion performances (burning rate, pressure exponent, combustion flame structure, etc.) for RDX-CMDB propellant were studied. The reasons affecting the combustion behaviors of RDX-CMDB propellant by the energetic catalyst and inert catalyst were analyzed. Results show that the combustion performances of the RDX-CMDB propellant with energetic catalyst are better than those of the RDX CMDB propellant with inert catalyst. The burning rate at 10 MPa increases from 11.74 mm·s^-1 for the propellant without catalyst to 25.36 mm·s^-1 for the propellant with E-Pb catalyst and the burning rate of the propellant increases with increasing the content of energetic catalyst. When the energetic lead salt and carbon black are matched, the catalytic effect of the propellant is better. When the mass ratio of carbon black and energetic lead salt is 1.5:0.25, a burning platform appears over the wide pressure ranging from 4 to 17 MPa and the pressure exponent n is less than 0.25.The effects of energetic lead salt on the combustion flame structure, thickness of dark space, number of bright spots on the combustion surface, etc. for propellant have certain regularities.

Abstract:To solve the cracks in the pressing process of RDX-based PBX(polymer bonded explosive), the influence of pressing temperature, cooling rate and heating rate on quality of Φ60 mm×60 mm RDX-based PBX were studied with ultrasonic, X-ray, and density detection. Results show that the number of cracks in the PBX diminish or eliminate when the cooling temperature is higher than 45 ℃, and the cooling and heating rates are less than 5 ℃·h^-1 in compaction process. Moreover, increasing pressing temperature improves the machining and pressing quality of the PBX.

Abstract:To investigate the fracture characteristics of ammonium perchlorate (AP) grains with different sizes within explosive substrate, three kinds of AP/HTPB samples were prepared using three kinds of AP grains with intermediate diameter of 6-8 μm, 30 μm and 300 μm. The samples were damaged by drop hammer impact loading. The samples after impact test were reclaimed and the fracture feature of AP grains was studied using scanning electron microscope (SEM).The fracture characteristics of AP grains with different sizes within explosive substrate under drop hammer impact loading were analyzed. Results show that after impact loading, lots of brittle ruptures of AP grains in three kinds of samples occurr, the shear bands can be seen in some samples, and the bigger the particles, the worse the fracture. The sizes of AP grains after fracture are between 10-100 μm, and the minimum size is less than 10 μm. Combined the shear band theory, the AP rupture characteristic and the rupture size of AP, ones can deduce that under drop hammer impact loading, the brittle ruptures of AP grains take place because of the shear effect of the sample inside, and the fracture size feature of the AP grains is similar to that of the shear bands in shear phenomena of materials.

Abstract:To characterize the fragmentation degree of propellant charge quantitatively, the concepts of dynamic vivacity ratio and initial dynamic vivacity ratio (IDVR) were introduced. The dynamic vivacity ratio, which is the ratio of burning surface area of fragmented propellant charge to the corresponding not-fragmented propellants charges, and IDVR, which is the ratio of burning surface area of fragmented propellant charge to the corresponding not-fragmented propellants charges at the initial time were deduced using the gas state equations of the closed bomb. The close bomb tests were done with three kinds of petal propellants with 19 holes and different lengths of 13.6 mm, 10 mm and 5 mm. The p -tcurves of the propellants with different lengths were obtained. The IDVR of the corresponding propellants was gained by processing the p-t curves. The initial surface area of propellants with different lengths was obtained via calculation based on the geometrical shape, and then the IDVRs of the propellants were obtained. Results show that the IDVRs′ results of tests are close to the calculated values, showing that the IDVR of the propellant can denote the fragmentation degree of fragmented propellant charge quantitatively.

Abstract:The launch safety of RDX-based aluminized explosive(R-Al explosive) was studied by 400 kg large drop hammer experiment and one-stage light-gas gun experiment. The stress-time curves of the explosive charge were obtained under the two different experimental conditions. Comparison of the launch safety of R-Al explosive and casting Comp.B was carried out. Results show that the ignition of R-Al explosive does not occur under the conditions of loading stress of 1.47 GPa and loading time of 3.04 ms for large drop hammer and loading stress of 660 MPa and loading time of 41 μs for one-stage light-gas gun. The ignition of casting Comp.B does occur under the conditions of loading stress of 840 MPa, loading time of 2.10 ms for large drop hammer and loading stress of 394 MPa, loading time of 40 μs for one-stage light-gas gun, revealing that the launch safety of R-Al explosive is better than that of casting Comp.B.

Abstract:The combustion gas temperature measurement system of rocket motor was established after temperature measurement principle utilizing Alexandrite effect was introduced, and the influences of the engine diameter and the heat loss on the axis temperature of combustion chamber were studied by numerical simulation. The combustion gas temperatures of three composite propellants with 1%, 9%, 17% aluminum at atmosphere(0.1 MPa), combustion chamber and nozzle exit with the motor working pressure of 5 MPa were measured. Results show that the engine diameter and the heat loss have little effect on the axis temperature of combustion chamber. The experimental combustion gas temperatures at atmosphere are 2857, 3109 K and 3284 K respectively, and the theoretical combustion gas temperatures are 2712, 2891 K and 3049 K, which demonstrates that with the increasing of aluminum content, the experimental and theoretical values all increase. The measured combustion gas temperature at nozzle exit is 2200 K, which agree with 2278 K through theoretical calculation. The measured gas temperature at combustion chamber are 2300 K and 2450 K, considerably lower than the theoretical values of 3190 K and 3450 K, which is probably because of the transparent glass window contaminated by combustion gas during engine working process. In order to accurately measure the gas temperature of rocket engine, the temperature measurement system must be further improved.

Abstract:With an ultra performance liquid chromatography (UPLC), a method for simultaneous determination was established for fourteen nitrophenol residues including 2, 4, 6-trinitrophenol [picric acid (PA)], 2, 4, 6-trinitroresorcinol [styphnic acid (TNR)] and 2, 4, 6-trinitrophloglucinol (TNPG) remained in soil and ground sediment of production areas of energetic materials. The sample extraction was completed in one procedure via a modified QuEChERS(quick, easy, cheap, effective, rugged, safe) pretreatment method. The samples were purified by C18 and graphitized carbon black (GCB). Fourteen nitrophenol compounds were separated by an Accucore PFP (2.1 mm×150 mm i.d., 2.6 μm)column, and the radiant elution was employed with a mobile phase consisting of acetonitrile and 0.02 mol·L^-1 ammonium acetate buffer solution, and 0.1% formic acid, a solvent flow rate of 0.3 mL·min^-1 and an injection volume of 5 μL. Fourteen nitrophenol compounds were identified at 220 nm. Results show that fourteen nitrophenol samples were linear in the concentration range of 0.2-50 mg·L^-1 with linear correlation coefficient ofof 0.9985-0.9995. The detection limits of the components were 0.04-0.06 mg·L^-1, and the average recoveries are 81.3%-105.7% with relative standard deviations of 3.6%-5.9%. Fourteen nitrophenol compounds were separated within 22 min. The established method can be applied to the rapid determination of nitrophenols residues in soil with good repeatability and precision.

Abstract:A high performance liquid chromatography (HPLC) to analyze main ingredient hexanitrostilbene (HNS) and the main impurity hexanitrobibenzyl (HNBB) was established. The method was carried out on a Hypersil ODS2 column (250 mm×4.6 mm, 5 μm) using acetonitrile-water (56/44, V/V) as the mobile phase at a flow rate of 0.70 mL·min^-1, and determined by a UV-visible detector at the wavelength of 226 nm. The column temperature was 25 ℃ and the injection volume was 10 μL. Results show that under the optimized chromatographic conditions, the calibration curves of HNS and HNBB have good linearity within the mass concentrations of 5-100 mg·L^-1 and 2-50 mg·L^-1, and the linear correlation coefficient r is greater than 0.999. The detection limits for HNS and HNBB were 0.60 mg·L^-1 and 0.31 mg·L^-1, respectively, and the quantification limits for the two were 2.00 mg·L^-1 and 1.02 mg·L^-1. The spiked recoveries are 99.60%-100.39% with the relative standard deviations (RSDs) between 1.63% and 2.07%. The method has wide linear range, high sensitivity and good reproducibility, and the results are accurate and reliable. The method can be used for the determination of the related substances in the product of HNS, and can meet the demand of the analysis of actual samples.

Abstract:In order to improve the design reliability of a retracting actuator, the reliability was analyzed and obtained by NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) software based on the stress-strength interference theory, and the sensitivity and importance analysis on random variables which affect the design reliability were also done. Results show that the design reliability of the acuator is 0.99999999986, and the relative error between the test value is 1.3E-10, which is acceptable in engineering. The parameters that have relatively greater effect on the reliability orderes in degree as following diameter of shear pin, active area of output pressure, gunpowder impetus and density of detonator output charge. The consistency of these parameters should be guaranteed in material selection and product processing.

Abstract:The progress on combustion catalysts of solid propellants in recent years was reviewed. The characteristics and development direction of combustion catalysts, such as metal, metallic oxide, composite metallic oxide, organo-metallic compounds, energetic catalyst and new carbon materials as well as the application investigation of quantum chemical calculation in combustion catalysts were summarized. It can be seen that the combustion catalysts have been developed from common single catalysts to nano-composite ones and from inert catalysts to energetic ones. Quantum chemical calculation can be used to study the catalytic mechanism, predict and calculate the structure and property of catalysts, and guide the synthesis of combustion catalysts and their applications. Considering that green environment protection is the theme of social development and the energetic catalysts possess dual advantages of energy and nanometer, investigation of the design and synthesis of green and insensitive composite energetic catalysts through quantum chemical calculation shall become the research focus of combustion catalysts in the future.

Abstract:The single-wall carbon nanotubes functional modified with tetrazoly groups(SWCNTs-CN₄) was firstly prepared by diazo-reaction on the wall of SWCNTs, and was characterized. Attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy show that the tetrazolyl groups are introduced to the surface of SWCNTs by covalent bond and hold the structure of five-ring. X-ray photoelectron spectroscopy (XPS) indicates that the N on the SWCNTs-CN₄ is about 14.8%. The ratio of tetrazolyl groups to carbon atoms of SWCNTs-CN₄ is about 4.9/100 by XPS calculation.

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