Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accident...Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.展开更多
OBJECTIVE AMPA-subtype iono⁃tropic glutamate receptors(iGluRs)mediate fast excitatory synaptic transmission in the mammali⁃an central nervous system(CNS).It plays the key role in many central nerves disorder such as e...OBJECTIVE AMPA-subtype iono⁃tropic glutamate receptors(iGluRs)mediate fast excitatory synaptic transmission in the mammali⁃an central nervous system(CNS).It plays the key role in many central nerves disorder such as epilepsy,depression and schizophrenia.Star⁃gazin(STZ,also named TARP-γ2),as the first TARPs found in CNS,potentiates AMPAR activity by attenuating deactivation and desensitization,enhancing recovery from desensitization,and facilitating agonist affinity and efficacy.However,it is still not fully understanding howγ-2 modu⁃late AMPAR gating.METHODS AND RESULTS The desensitization for different mutation of AMPAR andγ-2 was compared.It was shown that the electric attraction was involved in the interaction of AMPAR andγ-2.In addition,the interaction of KGK motif in ligand binding domain and pre-M1 chain of AMPAR and EX1 ofγ-2 modulate AMPAR opening and desensitization.Substitution of these charged residues had sur⁃prisingly effects on AMPAR desensitization kinet⁃ics.CONCLUSION The electric attraction has two impacts on the channels gating process the first destablizing the receptor closed state and enabling the channel opening,the second pro⁃moting the channels entering desensitization state upon the channel opening.展开更多
The desensitization of nitramine explosives while maintaining energetic performance is challenging.A highly efficient desensitizer is the key to solving the antinomy.This study focuses on using porous organic cages(PO...The desensitization of nitramine explosives while maintaining energetic performance is challenging.A highly efficient desensitizer is the key to solving the antinomy.This study focuses on using porous organic cages(POCs),specifically CC3 and RCC3,to desensitize RDX.By coating 0.1 wt%–5 wt%of POCs on RDX particles,a series of composite energetic materials were prepared.Characterization results show that POCs change the surface morphology of RDX,and there are interfacial interactions between them.The RDX@POCs composites exhibit enhanced stabilities in terms of heat,impact,friction,and electrostatic spark.For the RDX@RCC3-5%composite,the impact sensitivity(E_(IS)),friction sensitivity(E_(FS)),and electrostatic sensitivity(EES)were significantly reduced by 66.7%,68.8%,and 56.5%,respectively,while the detonation velocity decreased by merely 3.1%.These findings indicate that POCs,especially RCC3,are promising desensitizers for nitramine explosives,and their desensitization mechanisms likely involve barrier and buffering effects.The distinct desensitization behavior of RDX@RCC3 highlights the effectiveness of POCs in reducing the sensitivity of RDX without significantly compromising its energetic properties.展开更多
Carbon material is an important additive in energetic materials.Graphene is a monolayer carbon material in which carbon atoms are arranged in two-dimensional honeycomb structure,who has special optical,electrical,and ...Carbon material is an important additive in energetic materials.Graphene is a monolayer carbon material in which carbon atoms are arranged in two-dimensional honeycomb structure,who has special optical,electrical,and mechanical properties.Recently,the application of graphene-based composites in energetic materials has received extensive attention.This review mainly summarizes the applications of graphene and graphene-based nanomaterials in energetic materials.The effects of these materials on the thermal stability,sensitivity,mechanical property,ignition and combustion of energetic materials were discussed.Furthermore,the progress of functionalized modification of graphene has been summarized,including covalent bonding modification and doping modification.These studies show that graphenebased materials exhibit excellent performances and might emerge as promising candidate for energetic materials.展开更多
The interfacial interaction between HMX molecules and coating materials is the key to the safety performance of explosives and has received extensive attention.However,screening suitable coating agents to enhance the ...The interfacial interaction between HMX molecules and coating materials is the key to the safety performance of explosives and has received extensive attention.However,screening suitable coating agents to enhance the interfacial effect to obtain high-energy and low-sensitivity explosives has long been a major challenge.In this work,HMX-PEI/rGO/g-C_(3)N_(4)(HPrGC)composites were innovatively prepared by a multi-level coating strategy of two-dimensional graphite rGO and g-C_(3)N_(4).The g-C_(3)N_(4) used for desensitization has a richπ-conjugated system and shows outstanding ability in reducing friction sensitivity.The hierarchical structure of HPrGC formed by electrostatic self-assembly andπ-πstacking can effectively dissipate energy accumulation under heat and mechanical stimulation through structural evolution,thus exhibiting a prominent synergistic desensitization effect on HMX.The results show that rGO/gC_(3)N_(4) coating has no effect on the crystal structure and chemical structure of HMX.More importantly,the perfect combination of g-C_(3)N_(4) and rGO endows HPrGC with enhanced thermal stability and ideal mechanical sensitivity(IS:21 J,FS:216 N).Obviously,the new fabrication of HPrGC enriches the variety of desensitizer materials and helps to deepen the understanding of the interaction between explosives and coatings.展开更多
基金supported in part by the National Natural Science Foundation of China(No.22075146)。
文摘Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.
文摘OBJECTIVE AMPA-subtype iono⁃tropic glutamate receptors(iGluRs)mediate fast excitatory synaptic transmission in the mammali⁃an central nervous system(CNS).It plays the key role in many central nerves disorder such as epilepsy,depression and schizophrenia.Star⁃gazin(STZ,also named TARP-γ2),as the first TARPs found in CNS,potentiates AMPAR activity by attenuating deactivation and desensitization,enhancing recovery from desensitization,and facilitating agonist affinity and efficacy.However,it is still not fully understanding howγ-2 modu⁃late AMPAR gating.METHODS AND RESULTS The desensitization for different mutation of AMPAR andγ-2 was compared.It was shown that the electric attraction was involved in the interaction of AMPAR andγ-2.In addition,the interaction of KGK motif in ligand binding domain and pre-M1 chain of AMPAR and EX1 ofγ-2 modulate AMPAR opening and desensitization.Substitution of these charged residues had sur⁃prisingly effects on AMPAR desensitization kinet⁃ics.CONCLUSION The electric attraction has two impacts on the channels gating process the first destablizing the receptor closed state and enabling the channel opening,the second pro⁃moting the channels entering desensitization state upon the channel opening.
文摘The desensitization of nitramine explosives while maintaining energetic performance is challenging.A highly efficient desensitizer is the key to solving the antinomy.This study focuses on using porous organic cages(POCs),specifically CC3 and RCC3,to desensitize RDX.By coating 0.1 wt%–5 wt%of POCs on RDX particles,a series of composite energetic materials were prepared.Characterization results show that POCs change the surface morphology of RDX,and there are interfacial interactions between them.The RDX@POCs composites exhibit enhanced stabilities in terms of heat,impact,friction,and electrostatic spark.For the RDX@RCC3-5%composite,the impact sensitivity(E_(IS)),friction sensitivity(E_(FS)),and electrostatic sensitivity(EES)were significantly reduced by 66.7%,68.8%,and 56.5%,respectively,while the detonation velocity decreased by merely 3.1%.These findings indicate that POCs,especially RCC3,are promising desensitizers for nitramine explosives,and their desensitization mechanisms likely involve barrier and buffering effects.The distinct desensitization behavior of RDX@RCC3 highlights the effectiveness of POCs in reducing the sensitivity of RDX without significantly compromising its energetic properties.
基金funding support from Startup Foundation for Docotors of Yan’an University(Grant No.YAU205040372)Project of Science and Technology Office of Shaanxi Province(Grant No.2023-JC-QN-0152)。
文摘Carbon material is an important additive in energetic materials.Graphene is a monolayer carbon material in which carbon atoms are arranged in two-dimensional honeycomb structure,who has special optical,electrical,and mechanical properties.Recently,the application of graphene-based composites in energetic materials has received extensive attention.This review mainly summarizes the applications of graphene and graphene-based nanomaterials in energetic materials.The effects of these materials on the thermal stability,sensitivity,mechanical property,ignition and combustion of energetic materials were discussed.Furthermore,the progress of functionalized modification of graphene has been summarized,including covalent bonding modification and doping modification.These studies show that graphenebased materials exhibit excellent performances and might emerge as promising candidate for energetic materials.
基金the financial support from the National Natural Science Foundation of China (Grant No.51972278)the Open Project of the State Key Laboratory of Environment-friendly Energy Materials (Southwest University of Science and Technology,Grant No.20fksy16)。
文摘The interfacial interaction between HMX molecules and coating materials is the key to the safety performance of explosives and has received extensive attention.However,screening suitable coating agents to enhance the interfacial effect to obtain high-energy and low-sensitivity explosives has long been a major challenge.In this work,HMX-PEI/rGO/g-C_(3)N_(4)(HPrGC)composites were innovatively prepared by a multi-level coating strategy of two-dimensional graphite rGO and g-C_(3)N_(4).The g-C_(3)N_(4) used for desensitization has a richπ-conjugated system and shows outstanding ability in reducing friction sensitivity.The hierarchical structure of HPrGC formed by electrostatic self-assembly andπ-πstacking can effectively dissipate energy accumulation under heat and mechanical stimulation through structural evolution,thus exhibiting a prominent synergistic desensitization effect on HMX.The results show that rGO/gC_(3)N_(4) coating has no effect on the crystal structure and chemical structure of HMX.More importantly,the perfect combination of g-C_(3)N_(4) and rGO endows HPrGC with enhanced thermal stability and ideal mechanical sensitivity(IS:21 J,FS:216 N).Obviously,the new fabrication of HPrGC enriches the variety of desensitizer materials and helps to deepen the understanding of the interaction between explosives and coatings.
