Thermite films are typical energetic materials(EMs)and have great value in initiating explosive devices.However,research in thermite film preparation is far behind that of research in thermite powders.Electrophoretic ...Thermite films are typical energetic materials(EMs)and have great value in initiating explosive devices.However,research in thermite film preparation is far behind that of research in thermite powders.Electrophoretic deposition(EPD)is an emerging,rapid coating method for film fabrication,including of energetic composite films.In this work,a polytetrafluoroethylene(PTFE)/Al/CuO organic-inorganic hybrid energetic film was successfully obtained using the above method for the first time.The addition of lithocholic acid as a surfactant into the electroplating suspension enabled PTFE to be charged.The combustion and energy release were analyzed by means of a high-speed camera and differential scanning calorimetery(DSC).It was found that the combustion process and energy release of PTFE/Al/CuO were much better than that of Al/CuO.The main reason for the excellent combustion performance of the hybrid PTFE/Al/CuO system was that the oxidability of PTFE accelerated the redox reaction between Al and CuO.The prepared PTFE/Al/CuO film was also employed as ignition material to fire a B-KNO_3 explosive successfully,indicating considerable potential for use as an ignition material in micro-ignitors.This study sheds light on the preparation of fluoropolymer-containing organic-inorganic hybrid energetic films by one-step electrophoretic deposition.展开更多
With the development of two-stage munitions(a precursor shaped charge(SC)and a following kinetic energy projectile)to attack the hard concrete targets,as well as the increasing applications of ultra-high performance c...With the development of two-stage munitions(a precursor shaped charge(SC)and a following kinetic energy projectile)to attack the hard concrete targets,as well as the increasing applications of ultra-high performance concrete(UHPC)in both civil and military protective structures,a comparative study on the impact performance of SC formed jet on UHPC target is performed experimentally and numerically at present.Firstly,a series of jet penetration/perforation test on the UHPC,45# steel and UHPC/45# steel composite targets are conducted.By assessing the penetration depth and borehole(crater and tunnel)diameter,the influences of target material and configuration as well as the standoff distance of SC on the impact performance of jet are experimentally discussed.Then,by adopting the 2 D multi-material Arbitrary Lagrange-Euler(ALE)algorithm,Fluid-Structure Interaction(FSI)method and erosion algorithm implemented in the finite element code LS-DYNA,the formation and impact performance of jet in the present test are well reproduced.Finally,based on the validated numerical algorithms,constitutive models and the corresponding parameters,the influences of target material(UHPC,NSC and 45# steel),standoff distance,target configuration(stacked and spaced)and weight efficiency on the impact performance of jet are further discussed.The derived conclusions could provide helpful references for evaluating the ballistic performance of jet and designing the protective structures.展开更多
背景:胸腰椎骨折是最常见的脊柱骨折,中青年的胸腰椎骨折多由较大的外力造成,传统的长节段固定目前已被短节段的跨伤椎固定所取代,但是短节段固定易造成伤椎椎体高度的丢失,采用5钉三椎体固定近年逐渐成为主流的修复方式。目的:探讨后...背景:胸腰椎骨折是最常见的脊柱骨折,中青年的胸腰椎骨折多由较大的外力造成,传统的长节段固定目前已被短节段的跨伤椎固定所取代,但是短节段固定易造成伤椎椎体高度的丢失,采用5钉三椎体固定近年逐渐成为主流的修复方式。目的:探讨后路经伤椎一侧置钉联合短节段5钉内固定治疗不稳定型胸腰椎骨折的疗效。方法:回顾性分析徐州医科大学附属医院2012年1月至2015年12月采用后路经伤椎一侧置钉联合短节段5钉内固定治疗单节段胸腰椎骨折并获得1年以上随访的43例患者,根据术前、术后以及末次随访时的X射线片测量Cobb角,计算伤椎椎体前缘高度比值,观察内固定有无断裂、脱出,同时观察手术时间、出血量,采用目测类比评分评价术前术后疼痛。结果与结论:(1)43例患者均顺利完成手术,手术时间为60-125 min,平均80 mim;术中出血为50-400 m L,平均160 m L;(2)与术前相比,术后2周及末次随访时的伤椎椎体前缘高度比值均显著增大(t=10.15,9.57,P<0.05);末次随访时伤椎椎体前缘高度比值与术后2周相比,差异无显著性意义(t=0.42,P>0.05);(3)与术前相比,术后2周及末次随访时的Cobb角均显著减小(t=8.46,7.81,P<0.05);末次随访时的Cobb角与术后2周相比差异无显著性意义(t=0.93,P>0.05);(4)术后2周的目测类比评分显著低于术前(P<0.05);(5)所有患者均未发生内固定物断裂、脱出等并发症;(6)经伤椎一侧置钉联合短节段5钉内固定治疗不稳定型胸腰椎骨折可减小Cobb角,重建伤椎椎体前缘高度,且并发症较少,临床结果令人满意。展开更多
基金supported by National Natural Science Foundation of China(No.21905032)Natural Science Foundation of the Higher Education Institutions of Anhui Province(No.KJ2019A0687,No.KJ2016A503)+2 种基金High-level Humanities and Social Science Award Cultivation Project of Chaohu University and Innovation(No.kj20zkjp01,No.kj20xqyx02)Entrepreneurship Training Program for Students of National and school level(No.202010380014,X202010380013)Chaohu University for the Start-Up grant(No.KYQD-201907)。
文摘Thermite films are typical energetic materials(EMs)and have great value in initiating explosive devices.However,research in thermite film preparation is far behind that of research in thermite powders.Electrophoretic deposition(EPD)is an emerging,rapid coating method for film fabrication,including of energetic composite films.In this work,a polytetrafluoroethylene(PTFE)/Al/CuO organic-inorganic hybrid energetic film was successfully obtained using the above method for the first time.The addition of lithocholic acid as a surfactant into the electroplating suspension enabled PTFE to be charged.The combustion and energy release were analyzed by means of a high-speed camera and differential scanning calorimetery(DSC).It was found that the combustion process and energy release of PTFE/Al/CuO were much better than that of Al/CuO.The main reason for the excellent combustion performance of the hybrid PTFE/Al/CuO system was that the oxidability of PTFE accelerated the redox reaction between Al and CuO.The prepared PTFE/Al/CuO film was also employed as ignition material to fire a B-KNO_3 explosive successfully,indicating considerable potential for use as an ignition material in micro-ignitors.This study sheds light on the preparation of fluoropolymer-containing organic-inorganic hybrid energetic films by one-step electrophoretic deposition.
基金supported by the National Natural Science Foundation of China (51438003,51878507)
文摘With the development of two-stage munitions(a precursor shaped charge(SC)and a following kinetic energy projectile)to attack the hard concrete targets,as well as the increasing applications of ultra-high performance concrete(UHPC)in both civil and military protective structures,a comparative study on the impact performance of SC formed jet on UHPC target is performed experimentally and numerically at present.Firstly,a series of jet penetration/perforation test on the UHPC,45# steel and UHPC/45# steel composite targets are conducted.By assessing the penetration depth and borehole(crater and tunnel)diameter,the influences of target material and configuration as well as the standoff distance of SC on the impact performance of jet are experimentally discussed.Then,by adopting the 2 D multi-material Arbitrary Lagrange-Euler(ALE)algorithm,Fluid-Structure Interaction(FSI)method and erosion algorithm implemented in the finite element code LS-DYNA,the formation and impact performance of jet in the present test are well reproduced.Finally,based on the validated numerical algorithms,constitutive models and the corresponding parameters,the influences of target material(UHPC,NSC and 45# steel),standoff distance,target configuration(stacked and spaced)and weight efficiency on the impact performance of jet are further discussed.The derived conclusions could provide helpful references for evaluating the ballistic performance of jet and designing the protective structures.
文摘背景:胸腰椎骨折是最常见的脊柱骨折,中青年的胸腰椎骨折多由较大的外力造成,传统的长节段固定目前已被短节段的跨伤椎固定所取代,但是短节段固定易造成伤椎椎体高度的丢失,采用5钉三椎体固定近年逐渐成为主流的修复方式。目的:探讨后路经伤椎一侧置钉联合短节段5钉内固定治疗不稳定型胸腰椎骨折的疗效。方法:回顾性分析徐州医科大学附属医院2012年1月至2015年12月采用后路经伤椎一侧置钉联合短节段5钉内固定治疗单节段胸腰椎骨折并获得1年以上随访的43例患者,根据术前、术后以及末次随访时的X射线片测量Cobb角,计算伤椎椎体前缘高度比值,观察内固定有无断裂、脱出,同时观察手术时间、出血量,采用目测类比评分评价术前术后疼痛。结果与结论:(1)43例患者均顺利完成手术,手术时间为60-125 min,平均80 mim;术中出血为50-400 m L,平均160 m L;(2)与术前相比,术后2周及末次随访时的伤椎椎体前缘高度比值均显著增大(t=10.15,9.57,P<0.05);末次随访时伤椎椎体前缘高度比值与术后2周相比,差异无显著性意义(t=0.42,P>0.05);(3)与术前相比,术后2周及末次随访时的Cobb角均显著减小(t=8.46,7.81,P<0.05);末次随访时的Cobb角与术后2周相比差异无显著性意义(t=0.93,P>0.05);(4)术后2周的目测类比评分显著低于术前(P<0.05);(5)所有患者均未发生内固定物断裂、脱出等并发症;(6)经伤椎一侧置钉联合短节段5钉内固定治疗不稳定型胸腰椎骨折可减小Cobb角,重建伤椎椎体前缘高度,且并发症较少,临床结果令人满意。
