To develop new energy enhancement energetic materials with great combustion performance and thermal stability,two kinds of ternary thermite,Al/Fe_(2)O_(3)/CuO and Al/Fe_(2)O_(3)/Bi_(2)O_(3),were prepared and analyzed ...To develop new energy enhancement energetic materials with great combustion performance and thermal stability,two kinds of ternary thermite,Al/Fe_(2)O_(3)/CuO and Al/Fe_(2)O_(3)/Bi_(2)O_(3),were prepared and analyzed via mechanical ball milling.The samples were characterized by SEM,XRD,TG-DSC,constant volume and constant pressure combustion experiments.The first exothermic peaks of Al/Fe_(2)O_(3)/CuO and Al/Fe_(2)O_(3)/Bi_(2)O_(3) appear at 579°C and 564.5°C,respectively.The corresponding activation energies are similar.The corresponding mechanism functions are set as G(a) = [-ln(1-a)]^(3/4) and G(a) =[-ln(1-a)]2/3,respectively,which belong to the Avrami-Erofeev equation.Al/Fe_(2)O_(3)/CuO has better thermal safety.For small dose samples,its critical temperature of thermal explosion is 121.05°C higher than that of Al/Fe_(2)O_(3)/Bi_(2)O_(3).During combustion,the flame of Al/Fe_(2)O_(3)/CuO is spherical,and the main products are FeAl_(2)O_(4) and Cu.The flame of Al/Fe_(2)O_(3)/Bi_(2)O_(3)is jet-like,and the main products are Al_(2)O_(3),Bi and Fe.Al/Fe_(2)O_(3)/Bi_(2)O_(3)has better ignition and gas production performance.Its average ignition energy is 4.2 J lower than that of Al/Fe_(2)O_(3)/CuO.Its average step-up rate is 28.29 MPa/s,which is much higher than 6.84 MPa/s of Al/Fe_(2)O_(3)/CuO.This paper provides a reference for studying the thermal safety and combustion performance of ternary thermite.展开更多
Fluoropolymers get increasing attention in energetic materials application due to the high fluorine content.To explore the effect of poly(vinylidene fluoride-co-hexafluoropropylene)(P(VDF-HFP))on Al/MnO_(2) nanothermi...Fluoropolymers get increasing attention in energetic materials application due to the high fluorine content.To explore the effect of poly(vinylidene fluoride-co-hexafluoropropylene)(P(VDF-HFP))on Al/MnO_(2) nanothermite,the samples with different contents are prepared and characterized by SEM,TGDSC,XRD,and their ignition and combustion behavior are tested and recorded.The results show that P(VDF-HFP)as an energetic binder can combine the nanothermite components together,even exist in the gaps.The integrity of energetic materials has been improved.Thermal analysis shows that the addition of P(VDF-HFP)greatly changes the thermal reaction processes,and the exothermic peaks appear early,but the utilization of fuel and oxidizer is not efficient from the XRD results.Furthermore,the appropriate addition of P(VDF-HFP)can directly reduce the ignition energy threshold and increase the combustion time,which is necessary for the potential ignition charge application.The possible reasons for above phenomena are discussed and analyzed.This research provides a reference for improvement of thermitebased ignition charge formulation.展开更多
The p21 activated kinase 4(PAK4) is serine/threonine protein kinase that is critical for cancer progression.Guided by X-ray crystallography and structure-based optimization,we report a novel subseries of C-3-substitut...The p21 activated kinase 4(PAK4) is serine/threonine protein kinase that is critical for cancer progression.Guided by X-ray crystallography and structure-based optimization,we report a novel subseries of C-3-substituted 6-ethynyl-1 H-indole derivatives that display high potential and specificity towards group Ⅱ PAKs.Among these inhibitors,compound 55 exhibited excellent inhibitory activity and kinase selectivity,displayed superior anti-migratory and anti-invasive properties against the lung cancer cell line A549 and the melanoma cell line B16.Compound 55 exhibited potent in vivo antitumor metastatic efficacy,with over 80% and 90% inhibition of lung metastasis in A549 or B16-BL6 lung metastasis models,respectively.Further mechanistic studies demonstrated that compound 55 mitigated TGF-β1-induced epithelial-mesenchymal transition(EMT).展开更多
基金supported by the National Natural Science Foundation of China, project number: 51704302the Natural Science Foundation of Shaanxi Province, China, project number: Grant No.2020JC-50。
文摘To develop new energy enhancement energetic materials with great combustion performance and thermal stability,two kinds of ternary thermite,Al/Fe_(2)O_(3)/CuO and Al/Fe_(2)O_(3)/Bi_(2)O_(3),were prepared and analyzed via mechanical ball milling.The samples were characterized by SEM,XRD,TG-DSC,constant volume and constant pressure combustion experiments.The first exothermic peaks of Al/Fe_(2)O_(3)/CuO and Al/Fe_(2)O_(3)/Bi_(2)O_(3) appear at 579°C and 564.5°C,respectively.The corresponding activation energies are similar.The corresponding mechanism functions are set as G(a) = [-ln(1-a)]^(3/4) and G(a) =[-ln(1-a)]2/3,respectively,which belong to the Avrami-Erofeev equation.Al/Fe_(2)O_(3)/CuO has better thermal safety.For small dose samples,its critical temperature of thermal explosion is 121.05°C higher than that of Al/Fe_(2)O_(3)/Bi_(2)O_(3).During combustion,the flame of Al/Fe_(2)O_(3)/CuO is spherical,and the main products are FeAl_(2)O_(4) and Cu.The flame of Al/Fe_(2)O_(3)/Bi_(2)O_(3)is jet-like,and the main products are Al_(2)O_(3),Bi and Fe.Al/Fe_(2)O_(3)/Bi_(2)O_(3)has better ignition and gas production performance.Its average ignition energy is 4.2 J lower than that of Al/Fe_(2)O_(3)/CuO.Its average step-up rate is 28.29 MPa/s,which is much higher than 6.84 MPa/s of Al/Fe_(2)O_(3)/CuO.This paper provides a reference for studying the thermal safety and combustion performance of ternary thermite.
基金This work was supported by the National Natural Science Foundation,project no.51704302was also supported by China Scholarship Council,no.201903170086.
文摘Fluoropolymers get increasing attention in energetic materials application due to the high fluorine content.To explore the effect of poly(vinylidene fluoride-co-hexafluoropropylene)(P(VDF-HFP))on Al/MnO_(2) nanothermite,the samples with different contents are prepared and characterized by SEM,TGDSC,XRD,and their ignition and combustion behavior are tested and recorded.The results show that P(VDF-HFP)as an energetic binder can combine the nanothermite components together,even exist in the gaps.The integrity of energetic materials has been improved.Thermal analysis shows that the addition of P(VDF-HFP)greatly changes the thermal reaction processes,and the exothermic peaks appear early,but the utilization of fuel and oxidizer is not efficient from the XRD results.Furthermore,the appropriate addition of P(VDF-HFP)can directly reduce the ignition energy threshold and increase the combustion time,which is necessary for the potential ignition charge application.The possible reasons for above phenomena are discussed and analyzed.This research provides a reference for improvement of thermitebased ignition charge formulation.
基金supported by National Natural Science Foundation of China (Grant Nos.81230077,81872729 and 22077086)Overseas Expertise Introduction Project for Discipline Innovation (Grant No.D20029,China)Program for Innovative Talents of Higher Education of Liaoning (2012520005,China)。
文摘The p21 activated kinase 4(PAK4) is serine/threonine protein kinase that is critical for cancer progression.Guided by X-ray crystallography and structure-based optimization,we report a novel subseries of C-3-substituted 6-ethynyl-1 H-indole derivatives that display high potential and specificity towards group Ⅱ PAKs.Among these inhibitors,compound 55 exhibited excellent inhibitory activity and kinase selectivity,displayed superior anti-migratory and anti-invasive properties against the lung cancer cell line A549 and the melanoma cell line B16.Compound 55 exhibited potent in vivo antitumor metastatic efficacy,with over 80% and 90% inhibition of lung metastasis in A549 or B16-BL6 lung metastasis models,respectively.Further mechanistic studies demonstrated that compound 55 mitigated TGF-β1-induced epithelial-mesenchymal transition(EMT).
