Five polymer bonded explosives(PBXs)with the base explosive epsilon-CL-20(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703,GAP,HTPB,PEG,and F_(...Five polymer bonded explosives(PBXs)with the base explosive epsilon-CL-20(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703,GAP,HTPB,PEG,and F_(2314))were constructed.Molecular dynamics(MD)method was employed to investigate their binding energies(E_(bind))< compatibility,safety,mechanical properties,and energetic properties.The information and rules were reported for choosing better binders and guiding formulation design of high energy density material(HEDM).According to the calculated binding energies,the ordering of compatibility and stability of the five PBXs was predicted as epsilon-CL-20/PEG < epsilon-CL-20/ Estane5703 ≈ epsilon-CL-20/GAP < epsilon-CL-20/HTPB < epsilon-CL-20/F_(2314).By pair correlation function g(r)analyses,hydrogen bonds and vdw are found to be the main interactions between the two components.The elasticity and isotropy of PBXs based epsilon-CL-20 can be obviously improved more than pure epsilon-CL-20 crystal.It is not by changing the molecular structures of epsilon-CL-20 for each binder to affect the sensitivity.The safety and energetic properties of these PBXs are mainly influenced by the thermal capability(C_p^(deg))and density(p)of binders,respectively.展开更多
管理层讨论与分析(Management’s Discussion and Analysis,MD&A)最早起源于美国,它既包括公司管理层对过去业绩的评价和讨论,也包括对会影响公司未来的重要事件、趋势和不确定性的讨论与分析, 是对以报表和数字为主的传统会计报表...管理层讨论与分析(Management’s Discussion and Analysis,MD&A)最早起源于美国,它既包括公司管理层对过去业绩的评价和讨论,也包括对会影响公司未来的重要事件、趋势和不确定性的讨论与分析, 是对以报表和数字为主的传统会计报表的一个重要发展。但是如何规范公司管理层却面临诸多问题。本文主要论述了对MD&A进行审计的必要性和困难、美国证券交易委员会和美国公认审计准则在MD&A披露审计方面的有关规定,以及美国MD&A的相关审计制度值得我国借鉴的方面。展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 10176012)the Important Foundation of China Academy of Engineering Physics (CAEP, 2004Z0503) and 973 Program of China
文摘Five polymer bonded explosives(PBXs)with the base explosive epsilon-CL-20(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703,GAP,HTPB,PEG,and F_(2314))were constructed.Molecular dynamics(MD)method was employed to investigate their binding energies(E_(bind))< compatibility,safety,mechanical properties,and energetic properties.The information and rules were reported for choosing better binders and guiding formulation design of high energy density material(HEDM).According to the calculated binding energies,the ordering of compatibility and stability of the five PBXs was predicted as epsilon-CL-20/PEG < epsilon-CL-20/ Estane5703 ≈ epsilon-CL-20/GAP < epsilon-CL-20/HTPB < epsilon-CL-20/F_(2314).By pair correlation function g(r)analyses,hydrogen bonds and vdw are found to be the main interactions between the two components.The elasticity and isotropy of PBXs based epsilon-CL-20 can be obviously improved more than pure epsilon-CL-20 crystal.It is not by changing the molecular structures of epsilon-CL-20 for each binder to affect the sensitivity.The safety and energetic properties of these PBXs are mainly influenced by the thermal capability(C_p^(deg))and density(p)of binders,respectively.
文摘管理层讨论与分析(Management’s Discussion and Analysis,MD&A)最早起源于美国,它既包括公司管理层对过去业绩的评价和讨论,也包括对会影响公司未来的重要事件、趋势和不确定性的讨论与分析, 是对以报表和数字为主的传统会计报表的一个重要发展。但是如何规范公司管理层却面临诸多问题。本文主要论述了对MD&A进行审计的必要性和困难、美国证券交易委员会和美国公认审计准则在MD&A披露审计方面的有关规定,以及美国MD&A的相关审计制度值得我国借鉴的方面。
