为解决传统故障树(fault tree analysis, FTA)分析中建树困难、过于庞大和定性分析复杂的问题,提出了一种基于元动作全故障模式与改进二元决策图的故障树分析方法。首先,根据元动作全故障模式分析方法找出关键故障模式;其次,针对关键故...为解决传统故障树(fault tree analysis, FTA)分析中建树困难、过于庞大和定性分析复杂的问题,提出了一种基于元动作全故障模式与改进二元决策图的故障树分析方法。首先,根据元动作全故障模式分析方法找出关键故障模式;其次,针对关键故障模式,按照故障模式-参数-结构-原因的原则来查找基本原因,从而得到关键故障模式的故障树;再次,采用改进的二元决策图(binary decision graph, BDG)对建立的故障树进行定性分析,得到最小割集,并通过定量计算得到各底事件的相对概率重要度,找到关键的故障原因,为机电产品的设计和改进提供参考依据;最后,以三级行星齿轮减速器为例进行基于元动作的故障树分析,并与传统的故障树分析方法进行比较。最终结果验证了所述方法的适用性和有效性,提高了机电产品故障分析的通用性和分析效率。展开更多
The microstructure of computer generated nanocrystalline coppers is simulated by using molecular dynamics with Finnis-Sinclair potential,analysed by means of radial distribution functions,coordination number,atomic en...The microstructure of computer generated nanocrystalline coppers is simulated by using molecular dynamics with Finnis-Sinclair potential,analysed by means of radial distribution functions,coordination number,atomic energy and local crystalline order.The influence of the grain size on the nanocrystalline structure is studied.The results reveal that as the grain size is reduced,the grain boundary shows no significant structural difference,but the grain interior becomes more disordered,and their structural difference diminishes gradually;however,the density and the atomic average energy of the grain boundary present different tendencies from those of the grain interior.展开更多
The temperature behaviour of an Al bicrystal with surfaces consisting of (110) and (111) crystals is simulated using molecular dynamics. The result shows that the (110) crystal losses its crystalline order at 820K, wh...The temperature behaviour of an Al bicrystal with surfaces consisting of (110) and (111) crystals is simulated using molecular dynamics. The result shows that the (110) crystal losses its crystalline order at 820K, whereas the disorder does not propagate through the (111) crystal at this temperature. Instead, some disordered atoms are recrystallized into the (111) crystal and the initial grain boundary changes into a stable order-disorder interface. Thus, it was discovered that at a temperature near its melting point, the (111) crystal grew and obstructed the propagation of disorder. Such an obstruction is helpfulfor understanding melting.展开更多
Using an intense visible laser pulse to excite the liquid-filled waveguide with a long gain length,we have observed a new stimulated-scattering with super-broadened spectral width(500cm^(-1))in addition to the sharp l...Using an intense visible laser pulse to excite the liquid-filled waveguide with a long gain length,we have observed a new stimulated-scattering with super-broadened spectral width(500cm^(-1))in addition to the sharp lines of SRS of the benzene or carbon-disulfide which is used as a filling liquid.展开更多
文摘The microstructure of computer generated nanocrystalline coppers is simulated by using molecular dynamics with Finnis-Sinclair potential,analysed by means of radial distribution functions,coordination number,atomic energy and local crystalline order.The influence of the grain size on the nanocrystalline structure is studied.The results reveal that as the grain size is reduced,the grain boundary shows no significant structural difference,but the grain interior becomes more disordered,and their structural difference diminishes gradually;however,the density and the atomic average energy of the grain boundary present different tendencies from those of the grain interior.
基金Supported by the National Natural Science Foundation of China under Grant No.19772066.
文摘The temperature behaviour of an Al bicrystal with surfaces consisting of (110) and (111) crystals is simulated using molecular dynamics. The result shows that the (110) crystal losses its crystalline order at 820K, whereas the disorder does not propagate through the (111) crystal at this temperature. Instead, some disordered atoms are recrystallized into the (111) crystal and the initial grain boundary changes into a stable order-disorder interface. Thus, it was discovered that at a temperature near its melting point, the (111) crystal grew and obstructed the propagation of disorder. Such an obstruction is helpfulfor understanding melting.
文摘Using an intense visible laser pulse to excite the liquid-filled waveguide with a long gain length,we have observed a new stimulated-scattering with super-broadened spectral width(500cm^(-1))in addition to the sharp lines of SRS of the benzene or carbon-disulfide which is used as a filling liquid.
