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Mechanistic Insights into the Synthesis of Fully Condensed Polyhedral Octaphenylsilsesquioxane

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Chinese Journal of Chemistry 2019年第10期37卷 1051-1056页

作者： Zhao-Lu Qin Rong-jie Yang Wen-Chao Zhang qing-jie jiao National Engineering Research Center of Flame Retardant Materials School of MaterialsBeijing Institute of TechnologyBeijing 100081China School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

A comprehensive study on the efficient one-pot synthesis of polyhedral octaphenylsilsesquioxane (OPS) is reported via the hydrolytic condensation of phenyltrimethoxysilane (PTMS) in the presence of basic catalyst to investigate the specific synthesis *** synthetic reactions are monitored with real time infrared (RTIR) *** RTIR coupled with 29Si nuclear magnetic resonance spectroscopy (NMR) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) are used to monitor the reactions and identify the intermediary species during the *** rapid hydrolysis of PTMS is detected by *** to previous reports,the ladder-like structured species are identified as intermediates during the reaction *** is suggested that formation of caged T8OPS is realized through the chain break and rearrangement of the ladder-like ***,a scheme from hydrolysis of the PTMS to formation of the OPS is provided.

关键词： spectroscopy. mechanism. reaction.

Effect of the microporous structure of ammonium perchlorate on thermal behaviour and combustion characteristics

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Defence Technology（防务技术） 2022年第7期18卷 1156-1166页

作者： Hai-jun Zhang Jian-xin Nie Gang-ling jiao Xing Xu Xue-yong Guo Shi Yan qing-jie jiao State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Naval Research Institute of PLA Beijing100161China The Sixth Institute 601 Branch of China Aeronautical Science and Technology CorporationHohhot010076China

Ammonium perchlorate(AP)is the component with the highest content in composite propellants,and it plays a crucial role in propellant *** view of the effects of low-temperature AP thermal decomposition on thermal safety and combustion characteristics,porous ammonium perchlorate(PAP)samples with different mass losses were first prepared by thermal convection heating,and the structures were characterized and ***,the effects of decomposition degree on the thermal decomposition characteristics of PAP were studied by ***,the combustion characteristics of AP/Al binary mixtures were tested with high-speed photography and in a sealed *** results showed that low-temperature decomposition of AP resulted in formation of porous structures for AP *** pores first appeared near the surfaces of the particles and began from multiple points at the same *** pores increased in size to approximately 5 mm and then expanded,and finally,the AP particles were full of *** partial decomposition,the crystal structure of AP remained unchanged,but the low and high decomposition temperatures decreased *** decomposition rate *** to the porous structure of PAP,the combustion rate of the AP/Al system increased obviously with increasing decomposition of *** relationship between the combustion rate and the mass loss was approximately linear under open conditions,and it was exponential for a high-pressure environment.A computational model of the combustion process for the AP/Al binary system was established to explain the effects of pore structure and pressure on the combustion process.

关键词： Microporous structure Ammonium perchlorate Thermal behavior Porosity Combustion characteristics

Novel aluminum-based fuel:Facile preparation to improve thermal reactions

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Defence Technology（防务技术） 2022年第10期18卷 1852-1862页

作者： Fa-yang Guan Hui Ren Wan-jun Zhao Xin-zhou Wu qing-jie jiao State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

To improve the thermal properties of aluminum(Al)in the energetic system,a coated structure with ammonium perchlorate(AP)was prepared by a facile *** N,N-Dimethylformamide(DMF)was chosen as an ideal solvent based on heterogeneous nucleation theory and molecular dynamics *** coated structure could enlarge the contact area and improve the reaction environment to enhance the thermal *** addition of AP could accelerate oxidation temperature of Al with around 17.5°*** the heat release of 85@15 composition rises to 26.13 k J/g and the reaction degree is97.6%with higher peak pressure(254.6 k Pa)and rise rate(1.397 MPa/s).An ideal ratio with 15 wt%AP was probed *** high energy laser-induced shockwave experiment was utilized to simulate the reaction behavior in hot *** the larger activated mixture of coated powder could release more energy to promote the growth of shockwave with higher speed up to 518.7±55.9 m/*** conclusion,85@15 composition is expected to be applied in energetic system as a novel metal fuel.

关键词： Aluminum-based fuel Heterogeneous nucleation Molecular dynamics simulation Thermal reaction High energy laser-induced shockwave experiment

Effects of Al/O on pressure properties of confined explosion from aluminized explosives

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Defence Technology（防务技术） 2017年第6期13卷 428-433页

作者： Xiao-yu DUAN Xue-yong GUO qing-jie jiao Jing-yuan ZHANG qing-ming ZHANG Beijing Institute of Technology BeijingChina

Pressure histories were tested in a 500-L chamber to identify the pressure load in confined explosion from aluminized explosives. Different aluminized explosives with Al/O, ranging from 0.25 to 1.23, were used. The recorded pressure curves could express the reflection of initial shock wave and the after burning combustion of aluminum. As there is no objective way to gain quasi-static pressure(P_(QS)),method of multipoint averaging was used in smoothing the original pressure curves to gain the P_(QS). The P_(QS),rising time of pressure(t_(QS)) which stands for the duration of the initial reflected shock wave, and attenuation coefficient(ω) which stands for the supportive effects of the combustion of aluminum to the P_(QS) are used to characterize the pressure load in the confined explosion from aluminized explosives. The research results showed that the Al/O significantly affected the three characteristic quantities. With the increase of Al/O, the P_(QS) increased at first and decreased later, gaining maximum at Al/O=0.99; the t_(QS)sustained growth and the ω decreased at first and increased later, gaining minimum at AI/O=0.99.

关键词： Aluminized explosives Al/O Confined explosion Characteristic parameters

Structural response of aluminum core–shell particles in detonation environment

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Chinese Physics B 2019年第8期28卷 387-392页

作者： qing-jie jiao Qiu-Shi Wang Jian-Xin Nie Hong-Bo Pei State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China China Academy of Engineering Physics Institute of Fluid PhysicsMianyang 621900China

Natural aluminum particles have the core-shell *** structure response refers to the mechanical behavior of the aluminum particle structure caused by external *** dynamic behavior of the structural response of aluminum core-shell particles before combustion is of great importance for the aluminum powder burning mechanism and its *** this paper,an aluminum particle combustion experiment in a detonation environment is conducted and analyzed;the breakage factors of aluminum particles shell in detonation environment are *** experiment results show that the aluminum particle burns in a gaseous state and condenses into a sub-micron particle *** calculation and simulation demonstrate that the rupture of aluminum particle shell in the detonation environment is mainly caused by the impact of the detonation *** detonation wave impacts the aluminum particles,resulting in shell cracking,and due to the shrinkage-expansion of the aluminum core and stripping of the detonation product,the cracked shell is fractured and peeled with the aluminum reacting with the detonation product.

关键词： aluminum core-shell particles structural response aluminum combustion aluminized explosives

The properties of Sn-Zn-Al-La fusible alloy for mitigation devices of solid propellant rocket motors

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Defence Technology（防务技术） 2022年第9期18卷 1688-1696页

作者： Zi-ting Wei Nan Li Jian-xin Nie Jia-hao Liang Xue-yong Guo Shi Yan Tao Zhang qing-jie jiao State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

The Al and La elements are added to the Sn9Zn alloy to obtain the fusible alloy for the mitigation devices of solid propellant rocket motors. Differential scanning calorimetry(DSC), metallographic analysis,scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), tensile testing and fracture analysis were used to study the effect of Al and La elements on the microstructure, melting characteristics, and mechanical properties of the Sn9Zn alloy. Whether the fusible diaphragm can effectively relieve pressure was investigated by the hydrostatic pressure at high-temperature test. Experimental results show that the melting point of the Sn9Zn-0.8Al0·2La and Sn9Zn-3Al0·2La fusible alloys can meet the predetermined working temperature of ventilation. The mechanical properties of those are more than 35% higher than that of the Sn9Zn alloy at-50°C-70°C, and the mechanical strength is reduced by 80% at 175°C. It is proven by the hydrostatic pressure at high-temperature test that the fusible diaphragm can relieve pressure effectively and can be used for the design of the mitigation devices of solid propellant rocket motors.

关键词： Mitigation devices Solid propellant rocket motors Sn9Zn Al element La element Hydrostatic pressure at high-temperature test

Studies on aluminum powder combustion in detonation environment

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Chinese Physics B 2022年第4期31卷 426-435页

作者： Jian-Xin Nie Run-Zhe Kan qing-jie jiao Qiu-Shi Wang Xue-Yong Guo Shi Yan State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

The combustion mechanism of aluminum particles in a detonation environment characterized by high temperature(in unit 10^(3)K),high pressure(in unit GPa),and high-speed motion(in units km/s)was studied,and a combustion model of the aluminum particles in detonation environment was *** on this model,a combustion control equation for aluminum particles in detonation environment was *** can be seen from the control equation that the burning time of aluminum particle is mainly affected by the particle size,system temperature,and diffusion *** calculation result shows that a higher system temperature,larger diffusion coefficient,and smaller particle size lead to a faster burn rate and shorter burning time for aluminum *** considering the particle size distribution characteristics of aluminum powder,the application of the combustion control equation was extended from single aluminum particles to nonuniform aluminum powder,and the calculated time corresponding to the peak burn rate of aluminum powder was in good agreement with the experimental electrical conductivity *** equation can quantitatively describe the combustion behavior of aluminum powder in different detonation environments and provides technical means for quantitative calculation of the aluminum powder combustion process in detonation environment.

关键词： aluminum particle combustion model aluminum powder burn rate equation burning time

Learning Scalable Task Assignment with Imperative-Priori Conflict Resolution in Multi-UAV Adversarial Swarm Defense Problem

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Journal of Systems Science & Complexity 2024年第1期37卷 369-388页

作者： ZHAO Zhixin CHEN jie XIN Bin LI Li jiao Keming ZHENG Yifan School of Electronics and Information Engineering Tongji UniversityShanghai 201804China Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghai 201804China School of Automation Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Autonomous Intelligent Unmanned Systems Beijing 100081China Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghai 201804China.

The multi-UAV adversary swarm defense(MUASD)problem is to defend a static base against an adversary UAV swarm by a defensive UAV *** the problem into task assignment and low-level interception strategies is a widely used ***-based approaches for task assignment are a promising *** studies on learning-based methods generally assume decentralized decision-making architecture,which is not beneficial for conflict *** contrast,centralized decision-making architecture is beneficial for conflict resolution while it is often detrimental to *** achieve scalability and conflict resolution simultaneously,inspired by a self-attention-based task assignment method for sensor target coverage problem,a scalable centralized assignment method based on self-attention mechanism together with a defender-attacker pairwise observation preprocessing(DAP-SelfAtt)is ***,an imperative-priori conflict resolution(IPCR)mechanism is proposed to achieve conflict-free ***,the IPCR mechanism is parallelized to enable efficient *** validate the algorithm,a variant of proximal policy optimization algorithm(PPO)is employed for training in scenarios of various *** experimental results show that the proposed algorithm not only achieves conflict-free task assignment but also maintains scalability,and significantly improve the success rate of defense.

关键词： Conflict resolution reinforcement learning scalability task assignment.

High-Superelasticity NiTi Shape Memory Alloy by Directed Energy Deposition-Arc and Solution Heat Treatment

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 132-144页

作者： Junyi Ma Lin Yu qing Yang jie Liu Lei Yang State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430070China School of Transportation and Logistics Engineering Wuhan University of TechnologyWuhan430074China

Directed energy deposition-arc(DED-Arc)technology has the advantages of simple equipment,low manufacturing cost and high deposition rate,while the use of DED-Arc has problems of microstructure inhomogeneity,position dependence of macroscopic mechanical properties and ***,it is necessary to carry out a subsequent heat treatment to improve its microstructure uniformity,mechanical properties and *** this investigation,the DED-Arc 15-layer NiTi alloy thin-walled parts with the solution treatment at different process parameters were studied to analyze the effects of solution heat treatment on microstructure,phase composition,phase transformation,microhardness,tensile and *** temperature range of solution treatment is 800-1050℃,and the treatment time range is 1-5.5 *** results show that after solution treatment at 800℃/1 h,the content of precipitated phase decreases,the grain is refined,the microhardness increases,and the mechanical properties in the 0°direction are *** strain recovery rate after 10 tensile cycles has increased from 37.13%(as-built)to 49.25%(solid solution treatment).This research provides an effective post treatment method for high-performance DED-Arc NiTi shape memory alloys.

关键词： Directed energy deposition-arc(DED-Arc) Cold metal transfer(CMT) NiTi shape memory alloys Microstructure Phase transformation Solution heat treatment