The influence of Co, W and Ti on stress-rupture lives of a Ni-Cr-AI-Mo-Ta-Co-W-Ti single crystal nickel-base superalloy has been investigated using a L9 (34) orthogonal array design (OAD) by statistical analysis. ...The influence of Co, W and Ti on stress-rupture lives of a Ni-Cr-AI-Mo-Ta-Co-W-Ti single crystal nickel-base superalloy has been investigated using a L9 (34) orthogonal array design (OAD) by statistical analysis. At a selected composition range, Ti content was the most important factor to the effect of the stress-rupture lives and then followed by Co content. W content had the minimum effect on stress-rupture lives. The optimal alloy should contain 10 wt pct Co, 8 wt pct W and zero Ti. The optimized alloy also had good microstructural stability during thermal exposure at 870℃ for 500 h.展开更多
为消除场致发射电推力器(Field emission electric propulsion,FEEP)羽流发散角度过大给推进器寿命和可靠性带来的不利影响,研究了聚焦电极阵列空间位置对羽流聚焦效果的影响,并通过正交试验法给出了最优电极分布。通过数值仿真对FEEP...为消除场致发射电推力器(Field emission electric propulsion,FEEP)羽流发散角度过大给推进器寿命和可靠性带来的不利影响,研究了聚焦电极阵列空间位置对羽流聚焦效果的影响,并通过正交试验法给出了最优电极分布。通过数值仿真对FEEP的离子运动过程建模,采用正交试验方法电极阵列进行研究,关注其在不同空间位置下的聚焦效果,得到了离子出射半角分布和推力大小。结果表明,聚焦极的位置决定了羽流的聚焦效果,其次是提取极和加速极;聚焦极径向距离发射极1600μm,且提取极径向和轴向坐标为(800μm,500μm)时能得到最优的聚焦效果。本文验证了正交试验方法在聚焦电极阵列设计上的可行性,同时还为聚焦电极阵列设计提供了有效的分析方法和设计策略。展开更多
为降低企业推行JIT(Just In Time)的风险和成本,探讨了影响JIT系统性能的相关因素,运用中间变量建立了JIT系统的仿真模型;采用正交试验设计法选择仿真的优化因子,不仅考虑了因子对系统性能的影响,同时考虑了其经济性;结合企业实例,对JI...为降低企业推行JIT(Just In Time)的风险和成本,探讨了影响JIT系统性能的相关因素,运用中间变量建立了JIT系统的仿真模型;采用正交试验设计法选择仿真的优化因子,不仅考虑了因子对系统性能的影响,同时考虑了其经济性;结合企业实例,对JIT系统不同阶段优化方向的选择问题进行了进一步的探讨。展开更多
基金This work was supported by the National Natural Science Foundation of China under grand No.50474058.
文摘The influence of Co, W and Ti on stress-rupture lives of a Ni-Cr-AI-Mo-Ta-Co-W-Ti single crystal nickel-base superalloy has been investigated using a L9 (34) orthogonal array design (OAD) by statistical analysis. At a selected composition range, Ti content was the most important factor to the effect of the stress-rupture lives and then followed by Co content. W content had the minimum effect on stress-rupture lives. The optimal alloy should contain 10 wt pct Co, 8 wt pct W and zero Ti. The optimized alloy also had good microstructural stability during thermal exposure at 870℃ for 500 h.
文摘为消除场致发射电推力器(Field emission electric propulsion,FEEP)羽流发散角度过大给推进器寿命和可靠性带来的不利影响,研究了聚焦电极阵列空间位置对羽流聚焦效果的影响,并通过正交试验法给出了最优电极分布。通过数值仿真对FEEP的离子运动过程建模,采用正交试验方法电极阵列进行研究,关注其在不同空间位置下的聚焦效果,得到了离子出射半角分布和推力大小。结果表明,聚焦极的位置决定了羽流的聚焦效果,其次是提取极和加速极;聚焦极径向距离发射极1600μm,且提取极径向和轴向坐标为(800μm,500μm)时能得到最优的聚焦效果。本文验证了正交试验方法在聚焦电极阵列设计上的可行性,同时还为聚焦电极阵列设计提供了有效的分析方法和设计策略。
文摘为降低企业推行JIT(Just In Time)的风险和成本,探讨了影响JIT系统性能的相关因素,运用中间变量建立了JIT系统的仿真模型;采用正交试验设计法选择仿真的优化因子,不仅考虑了因子对系统性能的影响,同时考虑了其经济性;结合企业实例,对JIT系统不同阶段优化方向的选择问题进行了进一步的探讨。