Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This charact...Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This characteristic holds significant implications in the realm of novel satellite propulsion.Introducing a fraction of the electrical energy into energetic ionic liquid fuels,the thermal decomposition process is facilitated by reducing the apparent activation energy required,and electrical energy can trigger the electrochemical decomposition of ionic liquids,presenting a promising approach to enhance combustion efficiency and energy release.This study applied an external voltage during the thermal decomposition of 1-ethyl-3-methylimidazole nitrate([EMIm]NO_(3)),revealing the effective alteration of the activation energy of[EMIm]NO_(3).The pyrolysis,electrochemical decomposition,and electron assisted enhancement products were identified through Thermogravimetry-Differential scanning calorimetry-Fourier transform infrared-Mass spectrometry(TG-DSC-FTIR-MS)and gas chromatography(GC)analyses,elucidating the degradation mechanism of[EMIm]NO_(3).Furthermore,an external voltage was introduced during the combustion of[EMIm]NO_(3),demonstrating the impact of voltage on the combustion process.展开更多
MgH_(2),TiH_(2),and ZrH_(2) are three typical metal hydrides that have been gradually applied to composite explosives and propellants as additives in recent years.To evaluate ignition sensitivity and explosion severit...MgH_(2),TiH_(2),and ZrH_(2) are three typical metal hydrides that have been gradually applied to composite explosives and propellants as additives in recent years.To evaluate ignition sensitivity and explosion severity,the Hartmann device and spherical pressure vessel were used to test ignition energy and explosion pressure,respectively.The results showed that the ignition sensitivity of ZrH_(2),TiH_(2) and MgH_(2) gradually increased.When the concentration of MgH_(2) is 83.0 g/m^(3) in Hartmann device,the ignition energy attained a minimum of 10.0 mJ.The explosion pressure of MgH_(2) were 1.44 times and 1.76 times that of TiH_(2) and ZrH_(2),respectively,and the explosion pressure rising rate were 3.97 times and 9.96 times that of TiH_(2) and ZrH_(2),respectively,through the spherical pressure vessel.It indicated that the reaction reactivity and reaction rate of MgH_(2) were higher than that of TiH_(2) and ZrH_(2).In addition,to conduct in edepth theoretical analysis of ignition sensitivity and explosion severity,gas production and combustion heat per unit mass of ZrH_(2),TiH_(2) and MgH_(2) were tested by mercury manometer and oxygen bomb calorimetry.The experimental results revealed that MgH_(2) had a relatively high gas production per unit mass(5.15 mL/g),while TiH_(2) and ZrH_(2) both had a gas production of less than 2.0 mL/g.Their thermal stability gradually increased,leading to a gradual increase in ignition energy.Furthermore,compared with theoretical combustion heat,the combustion ratio of MgH_(2),TiH_(2) and ZrH_(2) was more than 96.0%,with combustion heat value of 29.96,20.94 and 12.22 MJ/kg,respectively,which was consistent with the explosion pressure and explosion severity test results.展开更多
To study the influence of B4C particle size on the microstructure and damping capacities of(B_(4)C+Ti)/Mg composites,in situ reactive infiltration technique was utilized to prepare Mg-matrix composites.The microstruct...To study the influence of B4C particle size on the microstructure and damping capacities of(B_(4)C+Ti)/Mg composites,in situ reactive infiltration technique was utilized to prepare Mg-matrix composites.The microstructure,produced phases and damping capacities of the composites prepared with different particle size of B4C were characterized and analyzed.The results show that the reaction between B4C and Ti tends to be more complete when finer B_(4)C particle was used to prepare the composites.But the microstructure of the as-prepared composites is more homogenous when B4C and Ti have similar particle size.The strain-dependent damping capacities of(B_(4)C+Ti)/Mg composites improve gradually with the increase of strain amplitude,and composites prepared with coarser B4C particles tend to have higher damping capacities.The temperature-dependent damping capacities improve with increasing the measuring temperatures,and the kind of damping capacities of the composites prepared with 5mm B4C are inferior to those of coarser particles.The dominant damping mechanism for the strain-damping capacity is dislocation damping and plastic zone damping,while that for the temperature-damping capacity is interface damping or grain boundary damping.展开更多
The pyrolysis of cyclohexane,methylcyclohexane,and ethylcyclohexane have been studied behind reflected shock waves at pressures of 5 and10 bar and at temperatures of 930-1550 K for 0.05%fuel diluted by Argon.A single-...The pyrolysis of cyclohexane,methylcyclohexane,and ethylcyclohexane have been studied behind reflected shock waves at pressures of 5 and10 bar and at temperatures of 930-1550 K for 0.05%fuel diluted by Argon.A single-pulse shock tube(SPST)is used to perform the pyrolysis experiments at reaction times varying from 1.65 to 1.74 ms.Major products are obtained and quantified using gas chromatography analysis.A flame ionization detector and a thermal conductivity detector are used for species identification and quantification.Kinetic modeling has been performed using several detailed and lumped chemical kinetic mechanisms.Differences in modeling results among the kinetic models are described.Reaction path analysis and sensitivity analysis are performed to determine the important reactions controlling fuel pyrolysis and their influence on the predicted concentrations of reactant and product species profiles.The present work provides new fundamental knowledge in understating pyrolysis characteristics of cyclohexane compounds and additional data set for detailed kinetic mechanism development.展开更多
Polymer bonded explosives(PBXs)have high energy density,excellent mechanical properties and better thermal stability.In this study,droplet microfluidic technology was used to successfully prepare HMX/TATB microspheres...Polymer bonded explosives(PBXs)have high energy density,excellent mechanical properties and better thermal stability.In this study,droplet microfluidic technology was used to successfully prepare HMX/TATB microspheres.The effects of different binder types and binder concentrations on the morphology of the microspheres were studied,and results proved that NC/GAP(1:4)provides particles a regular spherical morphology and good dispersion.Subsequently,the influence of the concentration of the dispersed phase and the flow rate of the continuous phase on the particle size distribution of the microspheres was fully studied.The microspheres had narrow particle size distribution and high spherical shape.Under optimized process conditions,HMX/TATB microspheres were prepared and compared with the physical mixtures.The X-ray diffraction,differential scanning calorimetry,flow properties,bulk density,and mechanical sensitivity of the samples were also studied.Results showed that the crystal form of the microspheres remains unchanged,and the binder maintains good compatibility with explosives.In addition,the fluidity,bulk density,real density and safety performance of the microspheres are remarkably better than the physical mixture.This study provides a new method for preparing PBX with narrow particle size distribution,high spherical shape,excellent dispersion and high bulk density.展开更多
Transient electronics is a versatile tool that finds applications in various fields,including medical biology,environmental protection,and data information security.In the context of data protection,the traditional pa...Transient electronics is a versatile tool that finds applications in various fields,including medical biology,environmental protection,and data information security.In the context of data protection,the traditional passive degradation transient mode is being replaced by the active destruction mode,which features a short self-destruction time and provides greater resistance to recovery.This article presents an overview of recent progress in transient electronics,assessing the benefits and suitability of varying transient mechanisms.The article also analyses the influence of transient electronics on military security while emphasizing the advantages of implementing energetic materials.Besides,the article introduces energetic transient devices and evaluates their ability to support the autonomous operation of transient electronic devices.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52206165)。
文摘Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This characteristic holds significant implications in the realm of novel satellite propulsion.Introducing a fraction of the electrical energy into energetic ionic liquid fuels,the thermal decomposition process is facilitated by reducing the apparent activation energy required,and electrical energy can trigger the electrochemical decomposition of ionic liquids,presenting a promising approach to enhance combustion efficiency and energy release.This study applied an external voltage during the thermal decomposition of 1-ethyl-3-methylimidazole nitrate([EMIm]NO_(3)),revealing the effective alteration of the activation energy of[EMIm]NO_(3).The pyrolysis,electrochemical decomposition,and electron assisted enhancement products were identified through Thermogravimetry-Differential scanning calorimetry-Fourier transform infrared-Mass spectrometry(TG-DSC-FTIR-MS)and gas chromatography(GC)analyses,elucidating the degradation mechanism of[EMIm]NO_(3).Furthermore,an external voltage was introduced during the combustion of[EMIm]NO_(3),demonstrating the impact of voltage on the combustion process.
基金This work was greatly supported by the Natural Science Foundation of China(11802272)the Open Research Fund Program of Science and Technology on Aerospace Chemical Power Laboratory(STACPL220181B01).
文摘MgH_(2),TiH_(2),and ZrH_(2) are three typical metal hydrides that have been gradually applied to composite explosives and propellants as additives in recent years.To evaluate ignition sensitivity and explosion severity,the Hartmann device and spherical pressure vessel were used to test ignition energy and explosion pressure,respectively.The results showed that the ignition sensitivity of ZrH_(2),TiH_(2) and MgH_(2) gradually increased.When the concentration of MgH_(2) is 83.0 g/m^(3) in Hartmann device,the ignition energy attained a minimum of 10.0 mJ.The explosion pressure of MgH_(2) were 1.44 times and 1.76 times that of TiH_(2) and ZrH_(2),respectively,and the explosion pressure rising rate were 3.97 times and 9.96 times that of TiH_(2) and ZrH_(2),respectively,through the spherical pressure vessel.It indicated that the reaction reactivity and reaction rate of MgH_(2) were higher than that of TiH_(2) and ZrH_(2).In addition,to conduct in edepth theoretical analysis of ignition sensitivity and explosion severity,gas production and combustion heat per unit mass of ZrH_(2),TiH_(2) and MgH_(2) were tested by mercury manometer and oxygen bomb calorimetry.The experimental results revealed that MgH_(2) had a relatively high gas production per unit mass(5.15 mL/g),while TiH_(2) and ZrH_(2) both had a gas production of less than 2.0 mL/g.Their thermal stability gradually increased,leading to a gradual increase in ignition energy.Furthermore,compared with theoretical combustion heat,the combustion ratio of MgH_(2),TiH_(2) and ZrH_(2) was more than 96.0%,with combustion heat value of 29.96,20.94 and 12.22 MJ/kg,respectively,which was consistent with the explosion pressure and explosion severity test results.
基金Project(51901095)supported by the National Natural Science Foundation of China。
文摘To study the influence of B4C particle size on the microstructure and damping capacities of(B_(4)C+Ti)/Mg composites,in situ reactive infiltration technique was utilized to prepare Mg-matrix composites.The microstructure,produced phases and damping capacities of the composites prepared with different particle size of B4C were characterized and analyzed.The results show that the reaction between B4C and Ti tends to be more complete when finer B_(4)C particle was used to prepare the composites.But the microstructure of the as-prepared composites is more homogenous when B4C and Ti have similar particle size.The strain-dependent damping capacities of(B_(4)C+Ti)/Mg composites improve gradually with the increase of strain amplitude,and composites prepared with coarser B4C particles tend to have higher damping capacities.The temperature-dependent damping capacities improve with increasing the measuring temperatures,and the kind of damping capacities of the composites prepared with 5mm B4C are inferior to those of coarser particles.The dominant damping mechanism for the strain-damping capacity is dislocation damping and plastic zone damping,while that for the temperature-damping capacity is interface damping or grain boundary damping.
文摘The pyrolysis of cyclohexane,methylcyclohexane,and ethylcyclohexane have been studied behind reflected shock waves at pressures of 5 and10 bar and at temperatures of 930-1550 K for 0.05%fuel diluted by Argon.A single-pulse shock tube(SPST)is used to perform the pyrolysis experiments at reaction times varying from 1.65 to 1.74 ms.Major products are obtained and quantified using gas chromatography analysis.A flame ionization detector and a thermal conductivity detector are used for species identification and quantification.Kinetic modeling has been performed using several detailed and lumped chemical kinetic mechanisms.Differences in modeling results among the kinetic models are described.Reaction path analysis and sensitivity analysis are performed to determine the important reactions controlling fuel pyrolysis and their influence on the predicted concentrations of reactant and product species profiles.The present work provides new fundamental knowledge in understating pyrolysis characteristics of cyclohexane compounds and additional data set for detailed kinetic mechanism development.
基金supported by the National Natural Science Foundation of China(No.22005275)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(STIP,No.2019L0584)the Advantage Disciplines Climbing Plan of Shanxi Province.
文摘Polymer bonded explosives(PBXs)have high energy density,excellent mechanical properties and better thermal stability.In this study,droplet microfluidic technology was used to successfully prepare HMX/TATB microspheres.The effects of different binder types and binder concentrations on the morphology of the microspheres were studied,and results proved that NC/GAP(1:4)provides particles a regular spherical morphology and good dispersion.Subsequently,the influence of the concentration of the dispersed phase and the flow rate of the continuous phase on the particle size distribution of the microspheres was fully studied.The microspheres had narrow particle size distribution and high spherical shape.Under optimized process conditions,HMX/TATB microspheres were prepared and compared with the physical mixtures.The X-ray diffraction,differential scanning calorimetry,flow properties,bulk density,and mechanical sensitivity of the samples were also studied.Results showed that the crystal form of the microspheres remains unchanged,and the binder maintains good compatibility with explosives.In addition,the fluidity,bulk density,real density and safety performance of the microspheres are remarkably better than the physical mixture.This study provides a new method for preparing PBX with narrow particle size distribution,high spherical shape,excellent dispersion and high bulk density.
基金supported by the National Natural Science Foun-dation of China(Grant No.52206165)Key R&D Projects in Sichuan Province(Grant No.2022YFG0219)。
文摘Transient electronics is a versatile tool that finds applications in various fields,including medical biology,environmental protection,and data information security.In the context of data protection,the traditional passive degradation transient mode is being replaced by the active destruction mode,which features a short self-destruction time and provides greater resistance to recovery.This article presents an overview of recent progress in transient electronics,assessing the benefits and suitability of varying transient mechanisms.The article also analyses the influence of transient electronics on military security while emphasizing the advantages of implementing energetic materials.Besides,the article introduces energetic transient devices and evaluates their ability to support the autonomous operation of transient electronic devices.
